User manual 3M ANISOTROPIC CONDUCTIVE FILM ADHESIVE 7313 TECH BULLETIN

[. . . ] Figure 1 shows the dynamic mechanical properties of ACF 7313. The storage modulus exhibits relatively stable values below the maximum use temperature (about 80°C). The crystalline melt temperature (where the modulus approaches a minimum value) is at about 115°C. Effective bonding requires that the bond-line temperature be high enough that the applied pressure is sufficient to achieve the necessary flow in the time allowed. [. . . ] Methods of tacking include: · Heating the film, for example with a hot-plate or infra-red lamp, and applying it to an unheated substrate. · Placing unheated film on a heated substrate, for example by placing the substrate on a hot-plate. · Placing unheated film on an unheated substrate and then heating both together, for example by feeding them through a heated laminator. Circuit Aligning The circuits must be brought in proper registration before bonding. This alignment step is normally performed using a camera and fixturing set-up or a microscope. Once the circuits are properly aligned they may require another tacking step to temporarily hold the assembly together. This tacking step can be performed in similar manner as the film tacking method described above. The circuits may not require this tacking step if the bonding equipment is designed to fixture the parts for both alignment and bonding operations. -2- Technical Bulletin Anisotropic Conductive Film Adhesive 7313 Bonding Process Development Thermode Bonding Constant Heat Bonder - Bond Profile Pressure Released Temperature Rise Time Bond Time Time -3- Figure 2. time for a constant-temperature thermode type bonder. Temperatures shown are measured in the adhesive bond-line using a higher thermode setpoint temperature. Thermode bonding, also referred to as hot-bar bonding, involves bringing a heated thermode into controlled-pressure contact with the previously aligned circuits to be bonded. This type of bonding is typical for bonding an interconnect circuit to a printed circuit board. Thermode bonders can utilize a constant temperature thermode or a pulsed-heat thermode with micro-processor-controlled variable temperature. Figure 2 shows an example of a temperature profile measured during the process of bonding a flex circuit to a printed circuit board using a constant-temperature thermode bonder. The bonding pressure is applied immediately at the start of the bond cycle, an continues uniformly throughout the bond cycle. The temperature rises quickly at first and then begins to level off. The temperature then slowly continuse to increase. Care must be taken to ensure that the maximum temperature is below the temperature at which the parts to be bonded could be damaged. The bond pressure is released after the full five seconds bond time is reached. When pressure is released with the adhesive at the peak temperature, the circuits may undergo slight separation before the adhesive cools below the recrystallization temperature. This may affect the mechanical and electrical performance. [. . . ] Please examine our entire line of conductive products for electronics at: www. 3m. com/electronicmaterials Product Use All statements, technical information and recommendations contained in this document are based upon tests or experience that 3M believes are reliable. However, many factors beyond 3M's control can affect the use and performance of a 3M product in a particular application, including the conditions under which the product is used and the time and environmental conditions in which the product is expected to perform. Since these factors 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. Warranty and Limited Remedy Unless stated otherwise in 3M's product literature, packaging inserts or product packaging for individual products, 3M warrants that each 3M product meets the applicable specifications at the time 3M ships the product. Individual products may have additional or different warranties as stated on product literature, package inserts or product packages. [. . . ]