3m ? thermally conductive adhesive tape 8940 / 8943 product information sheet 11.04.2007 supersedes version 01.10.2005 product description 3m tm thermally conductive adhesive tapes 8940 / 8943 are designed to provide an efficient h eat transfer path between heat generating components and heat sink s or other cooling devices. the tapes consist of a carrier, hi ghly loaded with thermally conductive fillers, coated on either one side (3m tm 8943) or both sides (3m tm 8940) with a high temperature resist ance acrylic pressure sensitive adhesive. the specialized construction secu rely bonds the heat generating components to heat sinks and offer both, good thermal conductivity and excellent electrical insulation properties. product construction 3m 8940 3m 8943 color beige carrier filled copolymer adhesive type modified acrylic adhesive tape type double coated single coated tape thickness 0.190mm 0.170 mm liner thickness 0,075 mm the film liner is a double sided si liconized polyester film with a differential release system. typical applications applications requiring good ther mal transfer and thin bonding. typical applications are assembling of power devi ces 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 applicatio ns such as engine control units bonding, abs systems, high power led?s, and other electronic increased power devices. 1
3m ? thermally conductive adhesive tapes 8940 / 8943 2/4 typical properties and performance characteristics note: the following tech nical information for 3m tm thermally conductive tape 8940 / 8943 should be considere d representative or typical only and should not be used for specification purposes. thermal properties test unit value test method thermal conductivity at 25 c w/m*k 0,9 astm d 5470 coefficient of thermal expansion (-40 to 150c) mm/c 140 e -06 tma electrical properties test unit value 8940 8943 test method breakdown voltage typical value * kv 10.3 9.8 iec 60243-1 dielectric strength typical value * kv/mm 55 52 iec 60243-1 volume resistivity *cm 2,5 x 10 13 astm d257 * average value (not for specification purposes) mechanical properties test unit value test method 20 min dwell time at room temp. n/cm 5,0 afera 5001 24 h dwell time room temp. n/cm 6,0 afera 5001 at 150 c n/cm 4,9 afera 5001 90 peel adhesion to aluminium substrate (almg 3 ; r a : 0,48 m; r z : )m) at 180 c n/cm 2,4 afera 5001 overlap shear 20 min dwell time at room temp. mpa 5,3 astm d 1002 24 h dwell time room temp. mpa 9,0 astm d 1002 after 24 h @ 150 c mpa 6,8 astm d 1002 after 24 h @ - 40 c mpa 9,0 astm d 1002 holding power 1000 g load @ room temp. minutes 10000+ afera 4012 500 g load @ 70 c minutes 10000+ afera 4012 tensile strength tensile strength n/mm2 6-7 en iso 527-2 elongation at break % 80-120 en iso 527-2 liner properties liner release cn/25,4 mm 15 finat tm3 thermal stability 225 c dwell @ 60 min (tape was applied between a glass and an aluminium panel) visual no change 3m temperature performance solder reflow process according to jedec j-std-020c (level 1) visual test in process 3m continuous operating temperature range c - 40 up to 150 3m
3m ? thermally conductive adhesive tapes 8940 / 8943 3/4 thermal resistance properties test unit value test method thermal gravimetric analysis * mass loss at 200 c % < 0,2 mass loss at 150 c after 4 h % < 0,3 3m flame class: ul 94 v-0, file e253171, flame rating applies to adhesive film (3m tm 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 prio r 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 oi ly components. allow the surface to dry for several minutes before applying the tape. more aggressive solv ents (such as acetone, methyl ethyl ketone (mek) or heptane) may be requi red to remove heavie r 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 manufacture rs? precautions and directions when using primers and solvents. 2) apply the tape to one substr ate 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 pa rts. the preferred pressure at room temperature is a minimum of 1 kg/cm 2 for 5 seconds. for fragile pa rts 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 mu ch 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 ma nufacture when stored at room temperature conditions 22c and 50% r.h. in the products original packaging.
3m ? thermally conductive adhesive tapes 8940 / 8943 4/4 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 suita ble for user?s method of application. please remember that many factors can affect the use and perfor mance of a 3m product in a particular app lication. the materials to be bonded with the product, th e surface preparation of thos e materials, the product selected for use, the conditio ns in which the product is used, and the time and environmental conditions in which the product is expected to perform are among the many facto rs 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 pr oduct, 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 th e user?s method of application. all ques tions of liability relating to the 3m produ ct 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 an d materials division carl-schurz-stra?e 1, 41453 neuss telefon 0 21 31 / 14 33 30 telefax 0 21 31 / 14 38 17 gedruckt auf chlorfrei gebleichtem papier
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