EPO-TEK H20E silver-filled conductive epoxy H20E
Two-part 100 % solids silver-filled epoxy: silver powder (at least 60 % of Part A by weight) in an epoxy phenol novolac resin (30 to 60 % of Part A by weight), per the Part A SDS
Also known as EPO-TEK® H20E
EPO-TEK H20E is a two-component, 100 % solids silver-filled epoxy made by Epoxy Technology.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Conduct current
0.0004 Ohm-cm or less
Carry heat
2.5 W/mK
Hold a die
1475 psi lap shear
Survive heat
80 °C or higher
Recipe, share of the weight
- Ag at least 60 % of Part A by weight (SDS)Silver
- 30 to 60 % of Part A by weight (SDS)Epoxy phenol novolac resin
Best for
Die attach where a conductive, solder-free joint is needed: volume resistivity of 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, cured at 150 °C for 1 hour
Weakest at
Heat flow compared with solder: junction-to-case thermal resistance of 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the datasheet TO-18 test, and no outgassing value found
Risk at a glance
- People Moderate. Classed as a skin irritant and skin sensitiser in the Part…
- If it fails Moderate. Higher thermal resistance than solder in the die attach
- Corrosion Low. The cured adhesive loses 0.59 % of its weight at 200 °C and 1.67 % at 300 °C, per the datasheet TGA weight-loss rows.
Quick facts: H20E
| Property | Value | Basis |
|---|---|---|
| Density | 2.03 to 3.07 | 3 sourced values across conditions |
| Thermal conductivity | 2.5 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 31 to 158 10^-6 in/in/°C | 2 sourced values across conditions |
| Electrical resistivity | 0.000004 Ω·m | 1 sourced value |
| Maximum service temperature | 200 to 300 °C | 2 sourced values across conditions |
What is the density of EPO-TEK H20E silver-filled conductive epoxy?
EPO-TEK H20E silver-filled conductive epoxy has a density of 2.03 to 3.07. The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the thermal conductivity of EPO-TEK H20E silver-filled conductive epoxy?
EPO-TEK H20E silver-filled conductive epoxy has a thermal conductivity of 2.5 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of EPO-TEK H20E silver-filled conductive epoxy?
EPO-TEK H20E silver-filled conductive epoxy has a coefficient of thermal expansion of 31 to 158 10^-6 in/in/°C. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the maximum service temperature of EPO-TEK H20E silver-filled conductive epoxy?
EPO-TEK H20E silver-filled conductive epoxy has a maximum service temperature of 200 to 300 °C. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is EPO-TEK H20E silver-filled conductive epoxy used for?
Uses recorded in the sources include Semiconductor die attach to lead frames; Thermal management in microelectronic packages; Hybrid microelectronics with GaAs chips for radar.
Why it exists
EPO-TEK H20E is a silver-filled two-part epoxy for attaching chips and making electrical connections in microelectronics. Its datasheet (Rev. XIX, August 2024) gives a volume resistivity of 0.0004 Ohm-cm or less at 23 °C and a thermal conductivity of 2.5 W/mK by laser flash. Engineers choose it where a conductive joint is needed without solder, and the datasheet calls it a NASA approved low outgassing adhesive.
Where it's used
Semiconductor die attach
The datasheet says the adhesive attaches chips to lead frames and is compatible with 260 °C lead-free reflow and JEDEC Level I packaging requirements. It can be snap-cured in line or cured in a box oven.
Thermal management
The datasheet says it is used extensively for thermal management because of its high thermal conductivity, quoted as 2.5 W/mK by laser flash.
Hybrid microelectronics and radar
The datasheet says it is used with GaAs chips for microwave and radar applications up to 77 GHz. It is described as a comparable alternative to solder and eutectic die attach, with no more than 1-2 °C/watt difference in thermal resistance in most cases.
Low-outgassing electronics
The datasheet calls it a NASA approved low outgassing adhesive. No outgassing value (TML, CVCM or ASTM E595 result) was found in the sources we hold, so the claim is recorded without a number.
Recipe
Two-part 100 % solids silver-filled epoxy: silver powder (at least 60 % of Part A by weight) in an epoxy phenol novolac resin (30 to 60 % of Part A by weight), per the Part A SDS
EPO-TEK H20E is a two-component, 100 % solids epoxy filled with silver powder. Part A and Part B are mixed 1:1 by weight. The product is also sold as a single-component frozen syringe. The datasheets do not give the process used to make the filler or the resin.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Silver Ag | at least 60 % of Part A by weight (SDS) | Conductive filler. The datasheet gives a maximum particle size of 45 microns. |
| Epoxy phenol novolac resin | 30 to 60 % of Part A by weight (SDS) | The binder that holds the silver and cures into a solid. Part B is not characterised in the sources read. |
Weight shares are as printed in the sources.
What it can do
Conduct current
0.0004 Ohm-cm or less
measured
Volume resistivity is 0.0004 Ohm-cm or less at 23 °C after a 150 °C, 1-hour cure, per the 2024 datasheet. The datasheet marks the figure as a lot-acceptance test.
Carry heat
2.5 W/mK
measured
Thermal conductivity is 2.5 W/mK by laser flash. The same datasheet also prints 29 W/mK from thermal resistance data, and it does not reconcile the two values.
Hold a die
1475 psi lap shear
measured
Lap shear is 1475 psi at 23 °C. Die shear is 3556 psi (at least 10 kg) in the 2024 datasheet, and 1700 psi in the 2010 copy.
Survive heat
80 °C or higher
measured
Glass transition is 80 °C or higher in the dynamic test. The datasheet prints a degradation temperature of 425 °C and a suggested intermittent operating limit of below 300 °C.
How it compares
EPO-TEK H20E is an adhesive, not a solder, and the datasheet compares it with solder only for thermal resistance. In the TO-18 test it gives 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder, so solder has the lower thermal resistance in that test. It is an electrical conductor at 0.0004 Ohm-cm or less, a figure the datasheet does not compare with any solder. For material comparisons, the 2.5 W/mK laser-flash conductivity is the value to use.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | H20E |
|---|---|
| Thermal behavior and safety | |
| Thermal conductivity, laser flash | 2.5 W/mK2 |
| Thermal conductivity, from thermal resistance data | 29 W/mK3 |
| Lifetime and stability | |
| Pot life after mixingPrinted as 2.5 Days in the header table | 2.5 days |
| Physical and electrical | |
| Volume resistivity at 23 °C | < 4×10^-4 Ohm-cm1 |
| Shore D hardness | 75 Shore D7 |
| Temperature behavior | |
| Glass transition temperature, dynamic test | > 80 °C4 |
| Degradation temperature by TGAPrinted as Degradation Temp. (TGA) 425 °C | 425 °C |
| Other measurements | |
| Coefficient of thermal expansion, below Tg | 31 10^-6 in/in/°C5 |
| Coefficient of thermal expansion, above Tg | 158 10^-6 in/in/°C6 |
| Lap shear strength at 23 °C | 1475 psi8 |
| Die shear strength at 23 °C, 2024 revision (psi) | > 3556 psi9 |
| Die shear strength at 23 °C, 2024 revision (kg) | > 10 kg10 |
| Die shear strength at 23 °C, 2010 copyPrinted as > 5 Kg / 1,700 psi in the 2010 copy | > 1700 psi11 |
| Weight loss at 200 °C | 0.59 %12 |
| Weight loss at 250 °C | 1.09 %13 |
| Weight loss at 300 °C | 1.67 %14 |
| Suggested operating temperature, intermittent (2024 datasheet) | < 300 °C15 |
| Operating temperature, continuous (2010 copy) | < 200 °C16 |
| Minimum operating temperature (2010 copy) | > -55 °C17 |
| Storage modulus at 23 °C | 8.09×10^5 psi18 |
| Viscosity at 100 rpm and 23 °C | 2200 to 3200 cPs19 |
| Thixotropic index | 4.6 -20 |
| Maximum particle size of the filled product | < 45 microns21 |
| Specific gravity, Part A | 2.03 -22 |
| Specific gravity, Part B | 3.07 -23 |
| Specific gravity, frozen syringe | 2.67 -24 |
| Chloride ion content | 73 ppm25 |
| Sodium ion content | 2 ppm26 |
| Ammonium ion content | 98 ppm27 |
| Potassium ion content | 3 ppm28 |
Why choose it, and why not
Good for
- Electrical and thermal conduction in die attach: 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, per the 2024 datasheet.
- Solder-free attach with a 150 °C cure, compatible with 260 °C lead-free reflow according to the datasheet.
- Hybrid and optoelectronic die attach, including IR detectors, LED dies and GaAs chips for radar up to 77 GHz.
Watch out for
- Thermal resistance is higher than solder in the TO-18 test: 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W.
- The two datasheet revisions disagree on die shear (3556 psi against 1700 psi) and on continuous operating temperature (200 °C in the 2010 copy only).
- No outgassing value was found, so the NASA approval claim cannot be checked against a number in this profile.
- The frozen-syringe SDS lists more hazards than the Part A SDS, including H302 and H318.
EPO-TEK H20E is a silver-filled conductive die-attach epoxy with a volume resistivity of 0.0004 Ohm-cm or less and a thermal conductivity of 2.5 W/mK by laser flash, both from the 2024 datasheet. Its junction-to-case thermal resistance is higher than solder's in the datasheet test, and no outgassing value was found to back the NASA approval claim.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Other names and standards
The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.
| System | Codes |
|---|---|
| Trade name | EPO-TEK® H20E |
Cell-level benchmarks
Values for finished cells. These vary by manufacturer, so read the conditions in the notes.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Volume resistivity at 23 °C | Printed as ≤ 0.0004 Ohm-cm; the datasheet marks the test as made on a lot-acceptance basis | temperature 23 °Ccure 150 °C / 1 hourtest basis asterisked in the datasheet as a lot-acceptance test | — |
| 2 | Thermal conductivity, laser flash | Printed as 2.5 W/mK based on the standard method Laser Flash | method as printed Laser Flashcure 150 °C / 1 hour | — |
| 3 | Thermal conductivity, from thermal resistance data | Printed by the manufacturer as derived from thermal resistance data, not measured by laser flash; the datasheet does not reconcile it with the laser-flash value | basis derived from thermal resistance data with the printed formula R = L x K-1 x A-1 | Two thermal conductivities are printed for the same adhesive: 2.5 W/mK by laser flash and 29 W/mK from thermal resistance data. Use the laser-flash value for material comparisons. |
| 4 | Glass transition temperature, dynamic test | Printed as ≥ 80 °C; the datasheet marks the test as a lot-acceptance test | method as printed Dynamic cure 20 to 200 °C, ISO 25 min; ramp -10 to 200 °C at 20 °C/mincure 150 °C / 1 hour | — |
| 5 | Coefficient of thermal expansion, below Tg | Printed as 31 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made | region below Tgcure 150 °C / 1 hour | — |
| 6 | Coefficient of thermal expansion, above Tg | Printed as 158 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made | region above Tgcure 150 °C / 1 hour | — |
| 7 | Shore D hardness | Typical value printed on the datasheet; test standard and temperature not printed | cure 150 °C / 1 hourtest temperature not printed | — |
| 8 | Lap shear strength at 23 °C | Typical value printed on the datasheet; test standard not printed | temperature 23 °Ccure 150 °C / 1 hour | — |
| 9 | Die shear strength at 23 °C, 2024 revision (psi) | Printed as ≥ 10 Kg / 3,556 psi in the 2024 datasheet | temperature 23 °Crevision Rev. XIX, August 2024 | The 2010 copy prints a lower figure, > 5 Kg / 1,700 psi. The two revisions disagree and the datasheet gives no reason. |
| 10 | Die shear strength at 23 °C, 2024 revision (kg) | Printed as ≥ 10 Kg in the same row as the psi figure | temperature 23 °Crevision Rev. XIX, August 2024 | — |
| 11 | Die shear strength at 23 °C, 2010 copy | — | temperature 23 °Crevision Rev. XI, February 2010 copy | Lower than the 2024 figure of 3,556 psi; the revisions disagree and the datasheet gives no reason. |
| 12 | Weight loss at 200 °C | Printed as 0.59 % weight loss at 200 °C; hold time and atmosphere not printed | temperature 200 °Chold time not printed | — |
| 13 | Weight loss at 250 °C | Printed as 1.09 % weight loss at 250 °C; hold time and atmosphere not printed | temperature 250 °Chold time not printed | — |
| 14 | Weight loss at 300 °C | Printed as 1.67 % weight loss at 300 °C; hold time and atmosphere not printed | temperature 300 °Chold time not printed | — |
| 15 | Suggested operating temperature, intermittent (2024 datasheet) | Printed as < 300 °C (Intermittent); the datasheet says the data are a guide and not a specification | use intermittent | — |
| 16 | Operating temperature, continuous (2010 copy) | Printed as Continuous -55 to 200 °C in the 2010 copy; the 2024 datasheet prints no continuous limit | use continuous | — |
| 17 | Minimum operating temperature (2010 copy) | Printed as -55 °C for both continuous and intermittent operation in the 2010 copy | use continuous and intermittent | — |
| 18 | Storage modulus at 23 °C | Printed as 808,700 psi; a dynamic storage modulus, not the elastic (Young's) modulus | temperature 23 °C | — |
| 19 | Viscosity at 100 rpm and 23 °C | Printed as 2,200 to 3,200 cPs; the datasheet marks it as a lot-acceptance test | speed 100 rpmtemperature 23 °Cstate before cure | — |
| 20 | Thixotropic index | Printed as 4.6 in the 2024 datasheet; the 2010 copy prints 4.63 | speed not printed | — |
| 21 | Maximum particle size of the filled product | Printed as ≤ 45 microns; the datasheet marks it as a lot-acceptance test | basis maximum, as printed | — |
| 22 | Specific gravity, Part A | Printed in the header table; temperature not printed | part Part Atemperature not printed | — |
| 23 | Specific gravity, Part B | Printed in the header table; temperature not printed | part Part Btemperature not printed | — |
| 24 | Specific gravity, frozen syringe | Printed in the header table as Syringe 2.67; temperature not printed | form single-component frozen syringetemperature not printed | — |
| 25 | Chloride ion content | Printed in the Ion Content row; test method not printed | basis as printed; test method and cure state not stated | — |
| 26 | Sodium ion content | Printed in the Ion Content row; test method not printed | basis as printed; test method and cure state not stated | — |
| 27 | Ammonium ion content | Printed in the Ion Content row; test method not printed | basis as printed; test method and cure state not stated | — |
| 28 | Potassium ion content | Printed in the Ion Content row; test method not printed | basis as printed; test method and cure state not stated | — |
| 29 | Junction-to-case thermal resistance, H20E die attach | Printed as 6.7 to 7.0 °C/W for EPO-TEK H20E in the TO-18 test | package TO-18 with nickel-gold metallised 20 x 20 mil chipsbond line 2 mils thick | — |
| 30 | Junction-to-case thermal resistance, solder die attach (comparison) | Printed as 4.0 to 5.0 °C/W for solder in the same TO-18 test | package TO-18 with nickel-gold metallised 20 x 20 mil chipsattach solder, type not printedbond thickness not printed for solder | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Heating of the cured adhesive (thermal ageing) | low | The cured adhesive loses 0.59 % of its weight at 200 °C and 1.67 % at 300 °C, per the datasheet TGA weight-loss rows.1 |
| Ionic residue in the cured adhesive (chloride and ammonium) | low | The datasheet prints 73 ppm chloride and 98 ppm ammonium in the adhesive.2 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Heating of the cured adhesive (thermal ageing) | Epoxy Technology prints weight loss at 200, 250 and 300 °C and a degradation temperature of 425 °C. The datasheet gives no hold times, atmosphere or post-heat test results, so these figures are not a service-life or ageing result. | basis manufacturer weight-loss figures; hold time and atmosphere not printedcure 150 °C / 1 hour |
| 2 | Ionic residue in the cured adhesive (chloride and ammonium) | These are the only corrosion-related numbers printed. The datasheet gives no test method, no limit, and no test against metal pads, so the corrosion effect of these ions is not quantified here. | basis Ion Content row only; no corrosion test printed |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
Both SDSs read here classify the product as an irritant and a sensitiser, so gloves and eye protection apply. The syringe SDS lists two trade-secret ingredients that add eye and oral hazards.
- Skin
- Part A causes skin irritation (H315) and may cause an allergic skin reaction (H317). The SDS names neoprene, nitrile or butyl rubber gloves.
- Eyes
- The frozen-syringe SDS classes the product as causing serious eye damage (H318). Wear safety glasses.
- Dust
- Harmful dust may be released during cutting, milling or grinding of the material. Avoid breathing the dust.
- Environment
- Silver is very toxic to aquatic life (H400) and very toxic with long lasting effects (H410). Avoid release to the environment.
If a joint runs hot
This is a heat-flow limit rather than a hazard. In the datasheet TO-18 test the adhesive joint has a higher thermal resistance than solder.
- Adhesive
- Junction-to-case thermal resistance is 6.7 to 7.0 °C/W for H20E in the TO-18 test, with 20 x 20 mil chips and a 2 mil bond line.
- Solder
- The same test prints 4.0 to 5.0 °C/W for solder. A higher value means a larger temperature rise per watt.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Higher thermal resistance than solder in the die attachmoderate severity | Junction-to-case thermal test on TO-18 packages with 20 x 20 mil chips and a 2 mil bond lineEPO-TEK H20E measures 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the same test, so the adhesive joint gives a larger temperature rise per watt. |
| Performance change after repackaginglow severity | The material is moved into syringes, bi-paks, cartridges, pouches or other containersThe manufacturer says performance may differ from the datasheet and its warranty does not apply to repackaged product. |
| Uneven filler and non-uniform propertieslow severity | Filled material not stirred thoroughly before mixing or useThe datasheet says filled systems should be stirred thoroughly before mixing and before use; the effect on conductivity is not quantified in the sources read. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Nearby optics, sensors or contacts in a vacuum (not tested in the sources read) | Weight loss on heating (0.59 % at 200 °C) means volatile material leaves the cured adhesive. The datasheet does not name the volatiles or measure outgassing. |
Handling and storage
- Mix Part A and Part B 1:1 by weight and use within the 2.5 day pot life.
- Shelf life is one year at room temperature for the bulk product and one year at -40 °C for the frozen syringe.
- Wear suitable gloves (neoprene, nitrile or butyl rubber), safety glasses and protective clothing; ensure good ventilation and avoid breathing dust.
- Stir filled material thoroughly before mixing and before use, and keep containers closed when not in use.
- Do not repackage the material into other containers without accepting that the manufacturer's warranty does not apply.
Mitigations
- Cure at the recommended 150 °C for 1 hour. The datasheet warns that minimum alternative cures may not achieve the performance properties.
Supply and geography
How common the raw materials are and where they come from.
Silver (main filler)
- Top producers (2025)
- Mexico 24.2%, Peru 13.8%, China 13.1%, Chile 5.4%
- Critical mineral lists
- US: listed
- Recycling
- USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025 in the US, about 11 % of apparent consumption.
- Substitutes
- USGS: stainless steel, tantalum and titanium may replace silver in surgical pins and plates, and nonsilver batteries may replace silver batteries in some applications. No substitute for silver in conductive epoxy is named in the text read.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: epo-tek-h20e
spore_version: 0.2
family: conductive-epoxy
name: EPO-TEK H20E silver-filled conductive epoxy
abbreviation: H20E
role: Two-part silver-filled epoxy for electrically and thermally conductive die attach
category: electronics
type: solders
summary: |
EPO-TEK H20E is a two-component, 100 % solids silver-filled epoxy made by Epoxy Technology. Its datasheet (Rev. XIX, August 2024) gives a volume resistivity of 0.0004 Ohm-cm or less at 23 °C and a thermal conductivity of 2.5 W/mK by laser flash. The datasheet calls it a NASA approved low outgassing adhesive, but no outgassing number was found in any source we hold.
best_for: 'Die attach where a conductive, solder-free joint is needed: volume resistivity of 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, cured at 150 °C for 1 hour'
weakest_at: 'Heat flow compared with solder: junction-to-case thermal resistance of 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the datasheet TO-18 test, and no outgassing value found'
identity:
formula: 'Two-part 100 % solids silver-filled epoxy: silver powder (at least 60 % of Part A by weight) in an epoxy phenol novolac resin (30 to 60 % of Part A by weight), per the Part A SDS'
source: epotek-tds-2024
where: Title block and Product Description (two components, 100 % solids); SDS Part A Section 3.2 for composition
designations:
- system: Trade name
code: EPO-TEK® H20E
source: meridian-h20e-page
where: Product page title
tags:
environments: []
stresses: []
applications:
- electronics-and-chips
- thermal-control
- optics-and-cameras
properties:
- benchmark: electrical_resistivity
label: Volume resistivity at 23 °C
value: 0.0004
bound: upper
unit: Ohm-cm
scope: material
conditions:
temperature: 23 °C
cure: 150 °C / 1 hour
test_basis: asterisked in the datasheet as a lot-acceptance test
method: Printed as ≤ 0.0004 Ohm-cm; the datasheet marks the test as made on a lot-acceptance basis
status: ground
source: epotek-tds-2024
where: Typical Properties, Electrical and Thermal Properties, Volume Resistivity row
- benchmark: thermal_conductivity
label: Thermal conductivity, laser flash
value: 2.5
unit: W/mK
scope: material
conditions:
method_as_printed: Laser Flash
cure: 150 °C / 1 hour
method: Printed as 2.5 W/mK based on the standard method Laser Flash
status: ground
source: epotek-tds-2024
where: Typical Properties, Electrical and Thermal Properties, first Thermal Conductivity row
- benchmark: thermal_conductivity
label: Thermal conductivity, from thermal resistance data
value: 29
unit: W/mK
scope: material
conditions:
basis: derived from thermal resistance data with the printed formula R = L x K-1 x A-1
method: Printed by the manufacturer as derived from thermal resistance data, not measured by laser flash; the datasheet does not reconcile it with the laser-flash value
status: calculated
note: 'Two thermal conductivities are printed for the same adhesive: 2.5 W/mK by laser flash and 29 W/mK from thermal resistance data. Use the laser-flash value for material comparisons.'
source: epotek-tds-2024
where: Typical Properties, Electrical and Thermal Properties, second Thermal Conductivity row
- benchmark: thermal_resistance_junction_to_case
label: Junction-to-case thermal resistance, H20E die attach
value: 6.7
value_high: 7
bound: range
unit: °C/W
scope: cell
conditions:
package: TO-18 with nickel-gold metallised 20 x 20 mil chips
bond_line: 2 mils thick
method: Printed as 6.7 to 7.0 °C/W for EPO-TEK H20E in the TO-18 test
status: ground
source: epotek-tds-2024
where: Typical Properties, Thermal Resistance (Junction to Case) row, H20E line
- benchmark: thermal_resistance_junction_to_case
label: Junction-to-case thermal resistance, solder die attach (comparison)
value: 4
value_high: 5
bound: range
unit: °C/W
scope: cell
conditions:
package: TO-18 with nickel-gold metallised 20 x 20 mil chips
attach: solder, type not printed
bond_thickness: not printed for solder
method: Printed as 4.0 to 5.0 °C/W for solder in the same TO-18 test
status: ground
source: epotek-tds-2024
where: Typical Properties, Thermal Resistance (Junction to Case) row, Solder line
- benchmark: glass_transition_temperature
label: Glass transition temperature, dynamic test
value: 80
bound: lower
unit: °C
scope: material
conditions:
method_as_printed: Dynamic cure 20 to 200 °C, ISO 25 min; ramp -10 to 200 °C at 20 °C/min
cure: 150 °C / 1 hour
method: Printed as ≥ 80 °C; the datasheet marks the test as a lot-acceptance test
status: ground
source: epotek-tds-2024
where: Typical Properties, Glass Transition Temp. (Tg) row
- benchmark: cte
label: Coefficient of thermal expansion, below Tg
value: 31
unit: 10^-6 in/in/°C
scope: material
conditions:
region: below Tg
cure: 150 °C / 1 hour
method: Printed as 31 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made
status: ground
source: epotek-tds-2024
where: Typical Properties, Coefficient of Thermal Expansion, Below Tg row
- benchmark: cte
label: Coefficient of thermal expansion, above Tg
value: 158
unit: 10^-6 in/in/°C
scope: material
conditions:
region: above Tg
cure: 150 °C / 1 hour
method: Printed as 158 x 10-6 in/in/°C; the datasheet uses inch units, so no conversion was made
status: ground
source: epotek-tds-2024
where: Typical Properties, Coefficient of Thermal Expansion, Above Tg row
- benchmark: shore_d_hardness
label: Shore D hardness
value: 75
unit: Shore D
scope: material
conditions:
cure: 150 °C / 1 hour
test_temperature: not printed
method: Typical value printed on the datasheet; test standard and temperature not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Shore D Hardness row
- benchmark: lap_shear_strength
label: Lap shear strength at 23 °C
value: 1475
unit: psi
scope: material
conditions:
temperature: 23 °C
cure: 150 °C / 1 hour
method: Typical value printed on the datasheet; test standard not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Lap Shear @ 23°C row
- benchmark: die_shear_strength
label: Die shear strength at 23 °C, 2024 revision (psi)
value: 3556
bound: lower
unit: psi
scope: material
conditions:
temperature: 23 °C
revision: Rev. XIX, August 2024
method: Printed as ≥ 10 Kg / 3,556 psi in the 2024 datasheet
status: ground
note: The 2010 copy prints a lower figure, > 5 Kg / 1,700 psi. The two revisions disagree and the datasheet gives no reason.
source: epotek-tds-2024
where: Typical Properties, Die Shear @ 23°C row
- benchmark: die_shear_strength
label: Die shear strength at 23 °C, 2024 revision (kg)
value: 10
bound: lower
unit: kg
scope: material
conditions:
temperature: 23 °C
revision: Rev. XIX, August 2024
method: Printed as ≥ 10 Kg in the same row as the psi figure
status: ground
source: epotek-tds-2024
where: Typical Properties, Die Shear @ 23°C row
- benchmark: die_shear_strength
label: Die shear strength at 23 °C, 2010 copy
value: 1700
bound: lower
unit: psi
scope: material
conditions:
temperature: 23 °C
revision: Rev. XI, February 2010 copy
method: Printed as > 5 Kg / 1,700 psi in the 2010 copy
status: ground
note: Lower than the 2024 figure of 3,556 psi; the revisions disagree and the datasheet gives no reason.
source: tedpella-tn16014
where: Typical Properties, Die Shear Strength @ 23 °C row
- benchmark: degradation_temperature
label: Degradation temperature by TGA
value: 425
unit: °C
scope: material
conditions:
method_as_printed: TGA
cure: 150 °C / 1 hour
method: Printed as Degradation Temp. (TGA) 425 °C
status: ground
source: epotek-tds-2024
where: Typical Properties, Degradation Temp. (TGA) row
- benchmark: weight_loss
label: Weight loss at 200 °C
value: 0.59
unit: '%'
scope: material
conditions:
temperature: 200 °C
hold_time: not printed
method: Printed as 0.59 % weight loss at 200 °C; hold time and atmosphere not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Weight Loss, @ 200°C row
- benchmark: weight_loss
label: Weight loss at 250 °C
value: 1.09
unit: '%'
scope: material
conditions:
temperature: 250 °C
hold_time: not printed
method: Printed as 1.09 % weight loss at 250 °C; hold time and atmosphere not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Weight Loss, @ 250°C row
- benchmark: weight_loss
label: Weight loss at 300 °C
value: 1.67
unit: '%'
scope: material
conditions:
temperature: 300 °C
hold_time: not printed
method: Printed as 1.67 % weight loss at 300 °C; hold time and atmosphere not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Weight Loss, @ 300°C row
- benchmark: max_service_temp
label: Suggested operating temperature, intermittent (2024 datasheet)
value: 300
bound: upper
unit: °C
scope: material
conditions:
use: intermittent
method: Printed as < 300 °C (Intermittent); the datasheet says the data are a guide and not a specification
status: ground
source: epotek-tds-2024
where: Typical Properties, Suggested Operating Temperature row
- benchmark: max_service_temp
label: Operating temperature, continuous (2010 copy)
value: 200
bound: upper
unit: °C
scope: material
conditions:
use: continuous
method: Printed as Continuous -55 to 200 °C in the 2010 copy; the 2024 datasheet prints no continuous limit
status: ground
source: tedpella-tn16014
where: Typical Properties, Operating Temp row
- benchmark: min_service_temp
label: Minimum operating temperature (2010 copy)
value: -55
bound: lower
unit: °C
scope: material
conditions:
use: continuous and intermittent
method: Printed as -55 °C for both continuous and intermittent operation in the 2010 copy
status: ground
source: tedpella-tn16014
where: Typical Properties, Operating Temp row
- benchmark: storage_modulus
label: Storage modulus at 23 °C
value: 808700
unit: psi
scope: material
conditions:
temperature: 23 °C
method: Printed as 808,700 psi; a dynamic storage modulus, not the elastic (Young's) modulus
status: ground
source: epotek-tds-2024
where: Typical Properties, Storage Modulus @ 23°C row
- benchmark: viscosity
label: Viscosity at 100 rpm and 23 °C
value: 2200
value_high: 3200
bound: range
unit: cPs
scope: material
conditions:
speed: 100 rpm
temperature: 23 °C
state: before cure
method: Printed as 2,200 to 3,200 cPs; the datasheet marks it as a lot-acceptance test
status: ground
source: epotek-tds-2024
where: Physical Properties, Viscosity (23°C) @ 100 rpm row
- benchmark: thixotropic_index
label: Thixotropic index
value: 4.6
unit: '-'
scope: material
conditions:
speed: not printed
method: Printed as 4.6 in the 2024 datasheet; the 2010 copy prints 4.63
status: ground
source: epotek-tds-2024
where: Physical Properties, Thixotropic Index row
- benchmark: particle_size
label: Maximum particle size of the filled product
value: 45
bound: upper
unit: microns
scope: material
conditions:
basis: maximum, as printed
method: Printed as ≤ 45 microns; the datasheet marks it as a lot-acceptance test
status: ground
source: epotek-tds-2024
where: Physical Properties, Particle Size row
- benchmark: pot_life
label: Pot life after mixing
value: 2.5
unit: days
scope: material
conditions:
mix: Part A and Part B 1:1 by weight
temperature: not printed
method: Printed as 2.5 Days in the header table
status: ground
source: epotek-tds-2024
where: Header table, Pot Life row
- benchmark: specific_gravity
label: Specific gravity, Part A
value: 2.03
unit: '-'
scope: material
conditions:
part: Part A
temperature: not printed
method: Printed in the header table; temperature not printed
status: ground
source: epotek-tds-2024
where: Header table, Specific Gravity, Part A row
- benchmark: specific_gravity
label: Specific gravity, Part B
value: 3.07
unit: '-'
scope: material
conditions:
part: Part B
temperature: not printed
method: Printed in the header table; temperature not printed
status: ground
source: epotek-tds-2024
where: Header table, Specific Gravity, Part B row
- benchmark: specific_gravity
label: Specific gravity, frozen syringe
value: 2.67
unit: '-'
scope: material
conditions:
form: single-component frozen syringe
temperature: not printed
method: Printed in the header table as Syringe 2.67; temperature not printed
status: ground
source: epotek-tds-2024
where: Header table, Specific Gravity, Syringe row
- benchmark: chloride_ion_content
label: Chloride ion content
value: 73
unit: ppm
scope: material
conditions:
basis: as printed; test method and cure state not stated
method: Printed in the Ion Content row; test method not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Ion Content, Cl- row
- benchmark: sodium_ion_content
label: Sodium ion content
value: 2
unit: ppm
scope: material
conditions:
basis: as printed; test method and cure state not stated
method: Printed in the Ion Content row; test method not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Ion Content, Na+ row
- benchmark: ammonium_ion_content
label: Ammonium ion content
value: 98
unit: ppm
scope: material
conditions:
basis: as printed; test method and cure state not stated
method: Printed in the Ion Content row; test method not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Ion Content, NH4+ row
- benchmark: potassium_ion_content
label: Potassium ion content
value: 3
unit: ppm
scope: material
conditions:
basis: as printed; test method and cure state not stated
method: Printed in the Ion Content row; test method not printed
status: ground
source: epotek-tds-2024
where: Typical Properties, Ion Content, K+ row
corrosion:
- environment: Heating of the cured adhesive (thermal ageing)
headline: The cured adhesive loses 0.59 % of its weight at 200 °C and 1.67 % at 300 °C, per the datasheet TGA weight-loss rows.
effect: Epoxy Technology prints weight loss at 200, 250 and 300 °C and a degradation temperature of 425 °C. The datasheet gives no hold times, atmosphere or post-heat test results, so these figures are not a service-life or ageing result.
rating: low
conditions:
basis: manufacturer weight-loss figures; hold time and atmosphere not printed
cure: 150 °C / 1 hour
source: epotek-tds-2024
where: Typical Properties, Weight Loss and Degradation Temp. (TGA) rows
- environment: Ionic residue in the cured adhesive (chloride and ammonium)
headline: The datasheet prints 73 ppm chloride and 98 ppm ammonium in the adhesive.
effect: These are the only corrosion-related numbers printed. The datasheet gives no test method, no limit, and no test against metal pads, so the corrosion effect of these ions is not quantified here.
rating: low
conditions:
basis: Ion Content row only; no corrosion test printed
source: epotek-tds-2024
where: Typical Properties, Ion Content row
risks:
hazards:
- text: 'Part A SDS (GHS US, revision 1/30/2023): skin irritation (H315), may cause an allergic skin reaction (H317), very toxic to aquatic life (H400) and very toxic to aquatic life with long lasting effects (H410). Signal word Warning.'
ghs:
- H315
- H317
- H400
- H410
source: epotek-h20e-sds-partA
where: Sections 2.1 and 2.2
- text: Frozen syringe SDS (revision 1/26/2023) adds harmful if swallowed (H302) and causes serious eye damage (H318). Its trade-secret ingredients are a reactive diluent (H302, H318, H336) and a substituted imidazole (H301, H315, H318, H335), each at 1 to 5 %.
ghs:
- H301
- H302
- H315
- H317
- H318
- H335
- H336
- H400
- H410
source: epotek-h20e-sds-syringe
where: Sections 2.1, 2.2 and 3.2
- text: 'Part A SDS: harmful dust may be released during cutting, milling or grinding of the product. Silver is at least 60 % of Part A by weight (CAS 7440-22-4).'
ghs: []
source: epotek-h20e-sds-partA
where: Section 2.3 and Section 3.2
- text: PubChem record for bulk silver (CID 23954) lists H400 and H410 from ECHA C&L Inventory aggregated notifications, and lists H361f and H373 under Regulation (EC) No 1272/2008 for silver massive (particle diameter 1 mm or larger). The page states the sources differ. These entries describe bulk silver, not the silver flake in H20E; the Part A SDS above is the product-level source.
ghs:
- H400
- H410
- H361f
- H373
source: pubchem-silver-ghs
where: GHS Classification section, ECHA C&L Inventory and Regulation (EC) No 1272/2008 entries
- text: The Epoxy Technology Part A material safety data sheet issued 11/20/96, which is older than the 2023 Part A SDS, lists silver flake at 60 % by weight with CAS 7440-22-4. It gives HMIS ratings of HEALTH 2, FIRE 1 and REACTIVITY 1, which the manufacturer says are estimated.
ghs: []
source: epotek-msds-1996
where: Section II, Hazardous Ingredients; HMIS and ANSI rating lines
failure_risks:
- mode: Higher thermal resistance than solder in the die attach
trigger: Junction-to-case thermal test on TO-18 packages with 20 x 20 mil chips and a 2 mil bond line
consequence: EPO-TEK H20E measures 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder in the same test, so the adhesive joint gives a larger temperature rise per watt.
severity: moderate
source: epotek-tds-2024
where: Typical Properties, Thermal Resistance (Junction to Case) rows
- mode: Performance change after repackaging
trigger: The material is moved into syringes, bi-paks, cartridges, pouches or other containers
consequence: The manufacturer says performance may differ from the datasheet and its warranty does not apply to repackaged product.
severity: low
source: epotek-tds-2024
where: Notes at the top of the datasheet
- mode: Uneven filler and non-uniform properties
trigger: Filled material not stirred thoroughly before mixing or use
consequence: The datasheet says filled systems should be stirred thoroughly before mixing and before use; the effect on conductivity is not quantified in the sources read.
severity: low
source: epotek-tds-2024
where: Notes at the top of the datasheet
side_effects:
- text: Weight loss on heating (0.59 % at 200 °C) means volatile material leaves the cured adhesive. The datasheet does not name the volatiles or measure outgassing.
affects: Nearby optics, sensors or contacts in a vacuum (not tested in the sources read)
source: epotek-tds-2024
where: Typical Properties, Weight Loss rows
handling:
- text: Mix Part A and Part B 1:1 by weight and use within the 2.5 day pot life.
source: epotek-tds-2024
where: Header table, Mix Ratio and Pot Life rows
- text: Shelf life is one year at room temperature for the bulk product and one year at -40 °C for the frozen syringe.
source: epotek-tds-2024
where: Header table, Shelf Life rows
- text: Wear suitable gloves (neoprene, nitrile or butyl rubber), safety glasses and protective clothing; ensure good ventilation and avoid breathing dust.
source: epotek-h20e-sds-partA
where: Sections 7.1 and 8.2 to 8.3
- text: Stir filled material thoroughly before mixing and before use, and keep containers closed when not in use.
source: epotek-tds-2024
where: Notes at the top of the datasheet
- text: Do not repackage the material into other containers without accepting that the manufacturer's warranty does not apply.
source: epotek-tds-2024
where: Notes at the top of the datasheet
mitigations:
- text: Cure at the recommended 150 °C for 1 hour. The datasheet warns that minimum alternative cures may not achieve the performance properties.
source: epotek-tds-2024
where: Header table, Recommended Cure and Minimum Alternative Cure(s)
uses:
- application: electronics-and-chips
device: Semiconductor die attach to lead frames
example: Die-attaching chips to lead frames; compatible with Si and MEMS chips, 260 °C lead-free reflow and JEDEC Level I packaging requirements.
source: epotek-tds-2024
where: Suggested Applications, Semiconductor IC Packaging
- application: thermal-control
device: Thermal management in microelectronic packages
example: Used extensively for thermal management applications due to its high thermal conductivity, which the datasheet quotes as 2.5 W/mK by laser flash.
source: epotek-tds-2024
where: Product Description
- application: electronics-and-chips
device: Hybrid microelectronics with GaAs chips for radar
example: Used with GaAs chips for microwave and radar applications up to 77 GHz; a comparable alternative to solder and eutectic die attach, very commonly no more than 1-2 °C/watt difference in thermal resistance.
source: epotek-tds-2024
where: Suggested Applications, Hybrid Micro-electronics
- application: optics-and-cameras
device: IR-detector and LED die attach for optoelectronics
example: Die-attaching IR-detector chips onto PCBs or TO-can style headers, and die-attaching LED chips to substrates; adhesion to Ag, Au and Cu plated lead frames and PCBs.
source: epotek-tds-2024
where: Suggested Applications, Opto-Electronic Packaging Applications
- application: electronics-and-chips
device: Electronics where outgassing is limited (datasheet claim)
example: The datasheet lists it as a NASA approved low outgassing adhesive; no outgassing value (TML, CVCM or ASTM E595 result) was found in the sources we hold.
source: epotek-tds-2024
where: Suggested Applications, Hybrid Micro-electronics, NASA approved bullet
supply:
- subject: Silver (main filler)
demand: In 2025 about 25 % of estimated US silver use went to electrical and electronics, and about 3 % to brazing and solder (USGS).
producers:
- country: Mexico
share_percent: 24.2
year: 2025
- country: Peru
share_percent: 13.8
year: 2025
- country: China
share_percent: 13.1
year: 2025
- country: Chile
share_percent: 5.4
year: 2025
critical_lists:
- list: USGS 2025 Final List of Critical Minerals (silver added in 2025)
listed: true
recycling: 'USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025 in the US, about 11 % of apparent consumption.'
substitutes:
- 'USGS: stainless steel, tantalum and titanium may replace silver in surgical pins and plates, and nonsilver batteries may replace silver batteries in some applications. No substitute for silver in conductive epoxy is named in the text read.'
source: usgs-mcs2026-silver
where: Domestic Production and Use; World Mine Production and Reserves table, 2025e (world total 26,000 t; country shares calculated by Space Mushroom from tonnages); Recycling; Substitutes; Critical minerals paragraph
documents:
- title: EPO-TEK H20E Technical Data Sheet, Rev. XIX (August 2024), copy on UCSB Protowiki
type: datasheet
url: https://protowiki.oasis.ucsb.edu/images/d/d1/H20E_EPOTEK.pdf
year: 2024
- title: EPO-TEK H20E Technical Data Sheet, Rev. XI (February 2010), Ted Pella technote 16014
type: datasheet
url: https://www.tedpella.com/technote_html/16014%20TN.pdf
year: 2010
- title: EPO-TEK H20E PART A Safety Data Sheet, revision 1/30/2023, version 2.0
type: sds
url: https://products.meridianadhesives.com/storage/downloads/iloirhohcbjiie5mr06wik5ayj0uwpnr/h20e-sds.pdf
year: 2023
- title: EPO-TEK H20E PMF SYRINGE Safety Data Sheet, revision 1/26/2023, version 2.0
type: sds
url: https://products.meridianadhesives.com/storage/downloads/9lssjbek3koy3xueumgabqjinafza2ea/h20e-pmf-syringe.pdf
year: 2023
- title: USGS Mineral Commodity Summaries 2026, Silver
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
year: 2026
- title: PubChem compound record for silver (CID 23954), GHS Classification
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/Silver
- title: Epoxy Technology Part A Material Safety Data Sheet, issued 11/20/96 (older copy, University of Waterloo)
type: sds
url: https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/default/files/uploads/files/epo-tech_h20e.pdf
year: 1996
gaps:
- 'No outgassing value found: the datasheet states only ''NASA approved low outgassing adhesive''. The NASA outgassing database search page returned no H20E results when fetched, and a web search for a TML, CVCM or ASTM E595 figure could not be run in this session because the search limit was reached.'
- The Meridian product page is recorded only for the product name. Its certification wording was read through a summary, not verbatim, so no certification text is quoted.
- The Part B (hardener) safety data sheet was not read. Only the Part A SDS and the frozen-syringe SDS were read, so Part B hazard classes are not confirmed.
- No space-environment data (vacuum, radiation, thermal cycling, flight heritage) was read in this run.
- Dielectric constant and dielectric strength are not printed in the datasheets read.
- Moisture absorption and humidity ageing are not printed in the datasheets read.
- Adhesion or resistivity after thermal cycling is not printed in the datasheets read.
- The 2010 and 2024 datasheets disagree on die shear, operating temperature and cure schedule. Both values are recorded side by side; the datasheets give no reason.
- The 29 W/mK thermal conductivity is derived from thermal resistance data. The datasheet gives the formula but no measured inputs.
- Silver supply shares are calculated by Space Mushroom from USGS 2025e mine production tonnages; USGS prints no shares for this table. The EU critical raw materials list was not checked for silver in this run.
- Silver recycling and substitute text describes silver metal in general, not conductive epoxy.
- No freely licensed photograph or diagram of H20E was fetched, so the media block is omitted.
- 'Several property names are not in the canonical file and are used as snake_case names: thermal_resistance_junction_to_case, lap_shear_strength, die_shear_strength, shore_d_hardness, degradation_temperature, weight_loss, storage_modulus, thixotropic_index, particle_size, pot_life, specific_gravity, chloride_ion_content, sodium_ion_content, ammonium_ion_content, potassium_ion_content.'
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 32
unreachable: 1
caveats: 3
note: Read by an AI assistant on 2026-11-01 from the pages named in each entry. The NASA outgassing database search page returned no H20E results. The Meridian product page was read through a summary. Two datasheet revisions (2024 and 2010) disagree on die shear, operating temperature and cure schedule; both values are recorded.
story:
recipe:
line: EPO-TEK H20E is a two-component, 100 % solids epoxy filled with silver powder. Part A and Part B are mixed 1:1 by weight. The product is also sold as a single-component frozen syringe. The datasheets do not give the process used to make the filler or the resin.
parts:
- name: Silver
symbol: Ag
share_note: at least 60 % of Part A by weight (SDS)
role: Conductive filler. The datasheet gives a maximum particle size of 45 microns.
- name: Epoxy phenol novolac resin
share_note: 30 to 60 % of Part A by weight (SDS)
role: The binder that holds the silver and cures into a solid. Part B is not characterised in the sources read.
risk_groups:
- title: For people
level: 2
verdict: Classed as a skin irritant and skin sensitiser in the Part…
lead: Both SDSs read here classify the product as an irritant and a sensitiser, so gloves and eye protection apply. The syringe SDS lists two trade-secret ingredients that add eye and oral hazards.
points:
- label: Skin
line: Part A causes skin irritation (H315) and may cause an allergic skin reaction (H317). The SDS names neoprene, nitrile or butyl rubber gloves.
- label: Eyes
line: The frozen-syringe SDS classes the product as causing serious eye damage (H318). Wear safety glasses.
- label: Dust
line: Harmful dust may be released during cutting, milling or grinding of the material. Avoid breathing the dust.
- label: Environment
line: Silver is very toxic to aquatic life (H400) and very toxic with long lasting effects (H410). Avoid release to the environment.
- title: If a joint runs hot
lead: This is a heat-flow limit rather than a hazard. In the datasheet TO-18 test the adhesive joint has a higher thermal resistance than solder.
points:
- label: Adhesive
line: Junction-to-case thermal resistance is 6.7 to 7.0 °C/W for H20E in the TO-18 test, with 20 x 20 mil chips and a 2 mil bond line.
- label: Solder
line: The same test prints 4.0 to 5.0 °C/W for solder. A higher value means a larger temperature rise per watt.
why: EPO-TEK H20E is a silver-filled two-part epoxy for attaching chips and making electrical connections in microelectronics. Its datasheet (Rev. XIX, August 2024) gives a volume resistivity of 0.0004 Ohm-cm or less at 23 °C and a thermal conductivity of 2.5 W/mK by laser flash. Engineers choose it where a conductive joint is needed without solder, and the datasheet calls it a NASA approved low outgassing adhesive.
uses:
- where: Semiconductor die attach
line: The datasheet says the adhesive attaches chips to lead frames and is compatible with 260 °C lead-free reflow and JEDEC Level I packaging requirements. It can be snap-cured in line or cured in a box oven.
- where: Thermal management
line: The datasheet says it is used extensively for thermal management because of its high thermal conductivity, quoted as 2.5 W/mK by laser flash.
- where: Hybrid microelectronics and radar
line: The datasheet says it is used with GaAs chips for microwave and radar applications up to 77 GHz. It is described as a comparable alternative to solder and eutectic die attach, with no more than 1-2 °C/watt difference in thermal resistance in most cases.
- where: Low-outgassing electronics
line: The datasheet calls it a NASA approved low outgassing adhesive. No outgassing value (TML, CVCM or ASTM E595 result) was found in the sources we hold, so the claim is recorded without a number.
can_do:
- label: Conduct current
benchmark: electrical_resistivity
value: 0.0004 Ohm-cm or less
line: Volume resistivity is 0.0004 Ohm-cm or less at 23 °C after a 150 °C, 1-hour cure, per the 2024 datasheet. The datasheet marks the figure as a lot-acceptance test.
- label: Carry heat
benchmark: thermal_conductivity
value: 2.5 W/mK
line: Thermal conductivity is 2.5 W/mK by laser flash. The same datasheet also prints 29 W/mK from thermal resistance data, and it does not reconcile the two values.
- label: Hold a die
benchmark: lap_shear_strength
value: 1475 psi lap shear
line: Lap shear is 1475 psi at 23 °C. Die shear is 3556 psi (at least 10 kg) in the 2024 datasheet, and 1700 psi in the 2010 copy.
- label: Survive heat
benchmark: glass_transition_temperature
value: 80 °C or higher
line: Glass transition is 80 °C or higher in the dynamic test. The datasheet prints a degradation temperature of 425 °C and a suggested intermittent operating limit of below 300 °C.
compare: EPO-TEK H20E is an adhesive, not a solder, and the datasheet compares it with solder only for thermal resistance. In the TO-18 test it gives 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W for solder, so solder has the lower thermal resistance in that test. It is an electrical conductor at 0.0004 Ohm-cm or less, a figure the datasheet does not compare with any solder. For material comparisons, the 2.5 W/mK laser-flash conductivity is the value to use.
compare_rows:
- label: Volume resistivity
benchmark: electrical_resistivity
- label: Thermal conductivity
benchmark: thermal_conductivity
- label: Junction-to-case thermal resistance
benchmark: thermal_resistance_junction_to_case
handling:
- Mix Part A and Part B 1:1 by weight and use within the 2.5 day pot life.
- Store the bulk product at room temperature and the frozen syringe at -40 °C; both have a one-year shelf life.
- Cure at 150 °C for 1 hour. The datasheet warns that minimum alternative cures may not reach the printed performance.
- Stir filled material thoroughly before mixing and before use, and keep containers closed.
- Wear gloves, safety glasses and protective clothing, and avoid breathing dust (Part A SDS).
- Do not repackage the material without accepting that the manufacturer's warranty does not apply.
good_for:
- 'Electrical and thermal conduction in die attach: 0.0004 Ohm-cm or less and 2.5 W/mK by laser flash, per the 2024 datasheet.'
- Solder-free attach with a 150 °C cure, compatible with 260 °C lead-free reflow according to the datasheet.
- Hybrid and optoelectronic die attach, including IR detectors, LED dies and GaAs chips for radar up to 77 GHz.
watch_out:
- 'Thermal resistance is higher than solder in the TO-18 test: 6.7 to 7.0 °C/W against 4.0 to 5.0 °C/W.'
- The two datasheet revisions disagree on die shear (3556 psi against 1700 psi) and on continuous operating temperature (200 °C in the 2010 copy only).
- No outgassing value was found, so the NASA approval claim cannot be checked against a number in this profile.
- The frozen-syringe SDS lists more hazards than the Part A SDS, including H302 and H318.
verdict: EPO-TEK H20E is a silver-filled conductive die-attach epoxy with a volume resistivity of 0.0004 Ohm-cm or less and a thermal conductivity of 2.5 W/mK by laser flash, both from the 2024 datasheet. Its junction-to-case thermal resistance is higher than solder's in the datasheet test, and no outgassing value was found to back the NASA approval claim.
sources:
epotek-tds-2024:
title: EPO-TEK H20E Technical Data Sheet, Rev. XIX (August 2024)
id: Epoxy Technology, Inc. EPO-TEK H20E TDS, Rev. XIX, August 2024
url: https://protowiki.oasis.ucsb.edu/images/d/d1/H20E_EPOTEK.pdf
year: 2024
kind: datasheet
license: manufacturer datasheet, cited not reproduced
tedpella-tn16014:
title: EPO-TEK H20E Technical Data Sheet, Rev. XI (February 2010), Ted Pella technote 16014
id: Epoxy Technology, Inc. EPO-TEK H20E TDS, Rev. XI, February 2010 (copy)
url: https://www.tedpella.com/technote_html/16014%20TN.pdf
year: 2010
kind: datasheet
license: manufacturer datasheet copy, cited not reproduced
meridian-h20e-page:
title: EPO-TEK H20E product page, Meridian Adhesives
id: Meridian Adhesives product page, accessed 2026-11-01
url: https://meridianadhesives.com/products/epo-tek-h20e/
kind: web
license: distributor web page, linked not reproduced
epotek-h20e-sds-partA:
title: EPO-TEK H20E PART A Safety Data Sheet (version 2.0)
id: Revision 1/30/2023; issue 3/2/2022; version 2.0
url: https://products.meridianadhesives.com/storage/downloads/iloirhohcbjiie5mr06wik5ayj0uwpnr/h20e-sds.pdf
year: 2023
kind: datasheet
license: supplier SDS, linked not reproduced
epotek-h20e-sds-syringe:
title: EPO-TEK H20E PMF SYRINGE Safety Data Sheet (version 2.0)
id: Revision 1/26/2023; issue 3/2/2022; version 2.0
url: https://products.meridianadhesives.com/storage/downloads/9lssjbek3koy3xueumgabqjinafza2ea/h20e-pmf-syringe.pdf
year: 2023
kind: datasheet
license: supplier SDS, linked not reproduced
usgs-mcs2026-silver:
title: Mineral Commodity Summaries 2026, Silver
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
year: 2026
kind: report
license: public domain (USGS)
pubchem-silver-ghs:
title: PubChem compound record for silver (CID 23954), GHS Classification
id: PubChem CID 23954; CAS 7440-22-4
url: https://pubchem.ncbi.nlm.nih.gov/compound/Silver
kind: database
license: public database record, linked not reproduced
epotek-msds-1996:
title: Epoxy Technology Part A Material Safety Data Sheet, issued 11/20/96
id: Epoxy Technology Inc., Billerica MA; date issued 11/20/96
url: https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/default/files/uploads/files/epo-tech_h20e.pdf
year: 1996
kind: datasheet
license: manufacturer SDS copy, linked not reproduced
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| EPO-TEK H20E Technical Data Sheet, Rev. XIX (August 2024) | datasheet | 2024 | 46 values | |
| EPO-TEK H20E Technical Data Sheet, Rev. XI (February 2010), Ted Pella technote 16014 | datasheet | 2010 | 3 values | |
| EPO-TEK H20E product page, Meridian Adhesives | web | 0 values | ||
| EPO-TEK H20E PART A Safety Data Sheet (version 2.0) | datasheet | 2023 | 3 values | |
| EPO-TEK H20E PMF SYRINGE Safety Data Sheet (version 2.0) | datasheet | 2023 | 1 value | |
| Mineral Commodity Summaries 2026, Silver | report | 2026 | 1 value | |
| PubChem compound record for silver (CID 23954), GHS Classification | database | 1 value | ||
| Epoxy Technology Part A Material Safety Data Sheet, issued 11/20/96 | datasheet | 1996 | 1 value |
Updated