3M™ Thermally Conductive Adhesive Tape 8940 / 8943 Product Information Sheet 11.04.2007 Supersedes Version 01.10.2005 Product Description 3MTM Thermally Conductive Adhesive Tapes 8940 / 8943 are designed to provide an efficient heat transfer path between heat generating components and heat sinks or other cooling devices. The tapes consist of a carrier, highly loaded with thermally conductive fillers, coated on either one side (3MTM 8943) or both sides (3MTM 8940) with a high temperature resistance acrylic pressure sensitive adhesive. The specialized construction securely bonds the heat generating components to heat sinks and offer both, good thermal conductivity and excellent electrical insulation properties. Product Construction 3M 8940 Color Carrier Adhesive type Tape type Tape Thickness Liner Thickness 3M 8943 Beige Filled Copolymer Modified Acrylic Adhesive Double coated Single coated 0.170 mm 0.190mm 0,075 mm The film liner is a double sided siliconized Polyester Film with a differential release system. Typical Applications 1 Applications requiring good thermal transfer and thin bonding. Typical applications are assembling of power devices as bare dies in chip on board technique or flip chip assemblies with a directly mounted heat sink. The tape performance properties have been primarily adapted to fit thermal requirements in applications such as Engine Control Units bonding, ABS Systems, High power LED’s, and other electronic increased power devices. 3M™ Thermally Conductive Adhesive Tapes 8940 / 8943 Typical Properties and Performance Characteristics Thermal Properties Note: The following technical information for 3MTM Thermally Conductive Tape 8940 / 8943 should be considered representative or typical only and should not be used for specification purposes. Test Thermal Conductivity at 25 °C Coefficient of Thermal Expansion (-40 to 150°C) Value 0,9 140 E -06 Test Method ASTM D 5470 TMA Unit Value 8940 8943 Test Method kV kV/mm Ω*cm 10.3 9.8 55 52 2,5 x 1013 IEC 60243-1 IEC 60243-1 ASTM D257 Unit Value Test Method 20 min dwell time at room temp. 24 h dwell time room temp. at 150 °C N/cm N/cm N/cm 5,0 6,0 4,9 AFERA 5001 AFERA 5001 AFERA 5001 at 180 °C N/cm 2,4 AFERA 5001 20 min dwell time at room temp. 24 h dwell time room temp. After 24 h @ 150 °C After 24 h @ - 40 °C MPa MPa MPa MPa 5,3 9,0 6,8 9,0 ASTM D 1002 ASTM D 1002 Test Electrical Properties Breakdown Voltage typical value * Dielectric Strength typical value * Volume Resistivity * Average value (not for specification purposes) Test Mechanical Properties 90° Peel Adhesion to Aluminium Substrate (AlMg3; Ra: 0,48 µm; Rz: )µm) Overlap Shear Unit W/m*K mm/°C ASTM D 1002 ASTM D 1002 Holding Power 1000 g load @ room temp. 500 g load @ 70 °C Minutes Minutes 10000+ 10000+ AFERA 4012 AFERA 4012 Tensile strength Tensile Strength Elongation at break N/mm² % 6-7 80-120 EN ISO 527-2 EN ISO 527-2 Liner properties Liner release cN/25,4 mm 15 FINAT TM3 Temperature Performance Thermal Stability 225 °C Dwell @ 60 min (Tape was applied between a glass and an aluminium panel) Solder Reflow process according to JEDEC J-STD-020C (Level 1) Continuous Operating Temperature Range Visual No Change 3M Visual Test in process - 40 up to 150 3M °C 3M 2/4 3M™ Thermally Conductive Adhesive Tapes 8940 / 8943 Thermal Resistance Properties Test Thermal Gravimetric Analysis * Mass loss at 200 °C Mass loss at 150 °C after 4 h Flame Class: Unit Value % % Test Method 3M < 0,2 < 0,3 UL 94 V-0, File E253171, Flame rating applies to adhesive film (3MTM Thermally conductive Tape 8940) bonded to 3.0 mm minimum thickness aluminium on one side and 0.86 mm minimum thickness FR-4 laminate on other side. Application Guidelines 1.) Substrate surfaces should be clean and dry prior to tape application. Isopropyl alcohol (isopropanol) applied with a lint-free wipe or swab should be adequate for removing surface contamination such as dust or finger prints. Do not use “denatured alcohol” or glass cleaners which often contain oily components. Allow the surface to dry for several minutes before applying the tape. More aggressive solvents (such as acetone, methyl ethyl ketone (MEK) or heptane) may be required to remove heavier contamination (grease, machine oils, solder flux, etc.) but should be followed by a final isopropanol wipe as described above. Note: Be sure to read and follow the manufacturers’ precautions and directions when using primers and solvents. 2) Apply the tape to one substrate at a modest angle with the use of a squeegee, rubber roller pressure to help reduce the possibility of air entrapment under the tape during its application. The liner can be removed after positioning the tape onto the first substrate. 3) Assemble the part by applying compression to the substrates to ensure a good wetting of the substrate surfaces with the tape. Proper application of pressure (amount of pressure, time applied, temperature applied) will depend upon design of the parts. The preferred pressure at room temperature is a minimum of 1 kg/cm2 for 5 seconds. For fragile parts lower pressure may be needed. Rigid substrates are more difficult to bond without air entrapment as most rigid parts are not flat. Flexible substrates can be bonded to rigid or flexible parts with much less concern about air entrapment because one of the flexible substrates can conform to the other substrate. Shelf Life Product shelf life is 2 years from date of manufacture when stored at room temperature conditions 22°C and 50% r.h. in the products original packaging. 3/4 3M™ Thermally Conductive Adhesive Tapes 8940 / 8943 Important Notice All statements, technical information and recommendations herein are based on tests we believe to be reliable, but the accuracy or completeness thereof is not guaranteed. User is responsible for determining whether the 3M product is fit for a particular purpose and suitable for user’s method of application. Please remember that many factors can affect the use and performance of a 3M product in a particular application. The materials to be bonded with the product, the surface preparation of those materials, the product selected for use, the conditions in which the product is used, and the time and environmental conditions in which the product is expected to perform are among the many factors that can affect the use and performance of a 3M product. Given the variety of factors that can affect the use and performance of a 3M product, some of which are uniquely within the user’s knowledge and control, it is essential that the user evaluate the 3M product to determine whether it is fit for a particular purpose and suitable for the user’s method of application. All questions of liability relating to the 3M product are governed by the terms of the sale subject, where applicable, to the prevailing law. 3M is a registered trademark of 3M Company. 3 3M Deutschland GmbH Electronics Markets and Materials Division Carl-Schurz-Straße 1, 41453 Neuss Telefon 0 21 31 / 14 33 30 Telefax 0 21 31 / 14 38 17 Gedruckt auf chlorfrei gebleichtem Papier 4/4