The Studys of Adhesion and Contact Thermal Resistance of TIM1

As the filler between the flip chip and lid, thermal interface material (TIM1) plays a role in heat dissipation to maintain the good performance of chips, lower power during operation. However, as the performance of the device itself continues to improve, in order to maintain reliability, the design demands for packaging materials such as TIM1 are increasing accordingly. Through the observation and analysis of TIM1 after working for a long time, the failure of the material is often due to the separation between the TIM1 and the chip or lid, which indicates that the interface interaction of the designed TIM1, that is, the adhesion is weak. Such problems can lead to a huge thermal resistance so that the thermal performance of TIM1 will be affected. In addition to the thermal resistance resulted from material failure, the contact thermal resistance of TIMl also can defeat its ability of thermal transport. Herein, the adhesion and contact thermal resistance of TIM1 are studied. In order to learn the term of contact thermal resistance, two types thermal testing method, laser flash and photo-thermal radiation are proposed. The research result shows that the adhesion has negative correlation with contact thermal resistance, two proposed method can work for the contact thermal resistance measurement. A method is probably to be used to improve the quality of TIM1 that is introducing adhesion promoter into it to enhance the adhesion at interface and defeat contact thermal resistance simultaneously.