3D Package Spacer Adhesion and Thickness Reduction
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Solution Overview
Problem
Conventional three-dimensional packages face issues with weak adhesion between silicon spacers and molding compounds due to material differences, leading to interface splitting during thermal cycles and increased thickness, which affects the 'light, thin, short, and small' package requirements.
Innovation Solution
The use of silicon as the material for both the spacer and the second chip enhances adhesion strength, and the elimination of the second molding compound between the spacer and the second chip prevents interface splitting and reduces package thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon spacer is bonded with a molding compound, then the package structure is formed, but the adhesion is weak due to material differences causing interface splitting during thermal cycles
Solution Approach 1:
The patent applies homogeneity by making the spacer and the chip it bonds to the same material (silicon). This eliminates the material mismatch between different substances, ensuring uniform thermal expansion coefficients and compatible bonding characteristics, thereby preventing interface splitting during thermal cycling while maintaining strong adhesion.
2Reliability
If a second molding compound is used to encapsulate the spacer and second chip, then the package is protected, but the overall thickness increases
Solution Approach 1:
The patent extracts and eliminates the second molding compound from the package structure. By removing this redundant encapsulation layer, the invention reduces the overall package thickness while still providing adequate protection through the first molding compound and the integrated spacer-chip assembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures strong adhesion and prevents interface splitting during thermal cycles, resulting in a thinner three-dimensional package that meets the 'light, thin, short, and small' design goals.
Implementation Method 1
the adhesion is not strong. When a thermal cycle test (TCT) is performed, the bonding interface between the spacer 18 and the second molding compound 17 may easily split
Data Source
AI summary
The present invention relates to a three-dimensional package and method of making the same. The package includes a first substrate, a first chip, a second substrate, a second chip, a spacer, and a first molding compound. The first chip is electrically connected to the first substrate. The second substrate is electrically connected to the first substrate. The second chip is electrically connected to the second substrate. One end of the spacer is attached to the first chip, and the other end of the spacer is attached to the second chip. The first molding compound encapsulates the first substrate, the first chip, the second substrate, the second chip, and the spacer. In the present invention, the adhesion between the spacer and the second chip is enhanced, and the overall thickness of the three-dimensional package is reduced.