Development of Build-up Dielectric Material that enables High Temp. Low Loss, High Fracture Toughness Advanced FC-BGA Substrates

Flip-chip BGA packaging utilizing organic build-up laminate substrates fabricated using semi-additive process are still commonly used for state-of-the-art IC devices such as CPUs, GPUs and ASICs. As IC devices become more advanced, FC-BGA packaging are also becoming more advanced pushing the development of advanced substrates. Some of the requirements are the needs for larger sized substrates with greater layer count to enable more routing lines and lower insertion loss performance even at elevated temperatures. However, enabling these challenges while maintaining high reliability, low cost and high substrate manufacturability yield is increasingly becoming more difficult and coupled with the increase in demand for advanced substrates have caused substrate shortages in recent years. To enable these challenges, while maintaining the need for high reliability, low cost, high manufacturing yields, improvement in materials that are major components of organic substrates, such as build-up dielectric materials, is necessary as these materials directly affects both signal integrity and reliability of the finished substrates. Thus, development of a new build-up dielectric material was attempted. Although, there are many trade-offs with regards to the material design of build-up dielectric material, by combining newly developed original resin with existing formulation technology, a material that enables low insertion loss even at elevated temperatures, have high fracture toughness, crack resistivity while maintaining good semi-additive process compatibility, thereby allowing good substrate manufacturability, was developed. In this paper, the material design philosophy as well as substrate level evaluation results such as insertion loss measurements and thermal shock reliability results are discussed.