Foam-Embedded Mold Substrate for IC Warpage Control

The patent uses a composite mold material layer comprising a resin matrix combined with high modulus particles (such as silica, alumina, or glass beads) to achieve both mechanical support and moldability. The resin matrix provides flexibility and moldability while the dispersed high modulus particles provide the necessary mechanical strength and warpage control, resolving the contradiction between strength and ease of manufacture.

The patent changes the material parameters of the mold material layer by incorporating foam structures with controlled density and distribution. The foam structures modify the mechanical properties and stress distribution characteristics of the substrate, allowing for effective warpage control upon release without requiring excessive carrier thickness. The foam density and cell structure are optimized to balance mechanical support with stress release capabilities.

The patent implements local quality by strategically placing foam structures at specific locations within the mold material layer where warpage control is most needed. The foam structures are distributed non-uniformly, with higher density in regions prone to warpage and lower density in regions requiring flexibility. This localized approach provides effective warpage control without requiring additional stiffeners or dummy devices throughout the entire substrate.

The patent uses the composite mold material layer with foam structures to provide differential mechanical support beneath the embedded bridges. The foam structures are positioned to compensate for the CTE mismatch effects specifically in the bridge regions, allowing high interconnect density to be achieved while maintaining warpage control. The composite structure absorbs thermal expansion stresses that would otherwise cause bridge warpage.