Stress Analysis for Bendable Electronic Module Under Thermal-Hygroscopic Complex Loads

Key Words: Bendable Electronic Module(유연성전자모듈), Thermal and Hygroscopic Loading(열·습도복합하중), Autoclave Test(오토클레이브시험)초록: 이동용전자기기에적용가능한유연성전자모듈이롤투롤공정에의해개발되었다. 개발된전자모듈은모듈내의폴리이미드층이유연성기판역할을하고그사이에동선과이방성도전필름과박막실리콘칩과모듈의봉지재역할을하는접착재료로구성된다. 개발된유연성전자모듈의신뢰성을평가하기위하여일련의인증시험을수행하였다. 시험수행결과열·습도복합하중조건인오토클레이브시험후에시편모듈내에박리가발생하였다. 오토클레이브시험에서열과습기가유연성전자모듈에어떤응력을발생시키는지를범용유한요소프로그램으로연구하였다. 열·흡습복합하중조건에서열과흡습에의한영향을분리하여상대적으로평가해보기위하여오토클레이브조건중온도조건에해당하는121°C 온도조건만을적용하여해석을별도수행하고두결과를비교하였다. 또한비교해석결과를바탕으로유연성전자모듈의고장메커니즘을추정하였다.Abstract: A bendable electronic module is developed. In this module, thin silicon electronic chips areembedded in a polymer-based encapsulating adhesive between flexible copper-clad polyimide layers. Duringthe qualification test of a harshly thermal-hygroscopic complex loading condition, delaminations occur insidethe module layers. A finite element model is developed for the module. To investigate the effect ofhygroscopic stress on delamination, the results of the thermal and thermal-hygroscopic loads are compared.The analysis results reveal that the hygroscopic effect more strongly affects delamination than does thethermal effect. The potential failure mechanisms of the module are investigated based on the stress analysis.