the most common problem in correctly bonding Btech’s thermoplastic ACF is to make sure that the thermoplastic resin reaches the correct bonding temperature.  During process development the best method is to use a fine wire thermocouple buried or attached to the adhesive film.

For example, a SUSS MicroTek FC150 flip chip bonder was used to bond a die to a PCB (0.013″ thick) with TP-2 (150C resin bonding temperature).  When the PCB was placed on a 165C hot plate it took 12 seconds to reach 150C on the bonding surface.  FC150 bonding trials were conducted with 190C bond head, 165C work stage, 50 psi for 15 seconds…but without an attached thermocouple there was no way to tell if the resin reached 150C.  It did not reach 150C and the resulting poor bond did not make any electrical connections.

Much shorter bond times for die/PCB either need the PCB surface to be pre-heated or the TP-2 to already be laminated to the PCB prior to final bonding.

We plan to post test results of various applications, bonding trials using different equipment and processes, and tips on how to determine if your bonding process is producing a good bond with the proper Z-axis conductivity and mechanical properties.

We welcome your questions and comments about your own experience with our highly electrically and thermally conductive thermoplastic adhesive films.