Semiconductor Chip Adhesive Layer for Cavity-Free Gap Filling
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Solution Overview
Problem
The challenge in semiconductor packaging is the formation of cavities due to incomplete filling of the gap between the wiring substrate and the die attach film, leading to high pressure and potential damage from moisture expansion during heat treatments, which affects the reliability of the package.
Innovation Solution
A semiconductor device design that incorporates an adhesive layer with multiple resin types of varying molecular weights and filler concentrations, allowing for the formation of a secondary adhesive layer to fill gaps and reduce pressure within the package, thereby preventing damage during heat treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a die attach film is used to stack semiconductor chips, then chip stacking is achieved, but cavities form due to incomplete gap filling
Solution Approach 1:
The adhesive layer is segmented into multiple resin types with different molecular weights, allowing the lower molecular weight resin to flow into and fill the gap between substrate and die attach film, while the higher molecular weight resin provides structural support. This segmentation enables both complete gap filling and structural integrity.
Solution Approach 2:
The invention changes the parameter of resin molecular weight distribution in the adhesive layer, using a combination of resins with different molecular weights. This parameter change allows the adhesive material to exhibit both flowability (for gap filling) and structural strength (for chip support) simultaneously.
2Reliability
If cavities are present in the package, then moisture expansion pressure damages the package during heat treatment, but eliminating cavities requires complete gap filling
Solution Approach 1:
The gap filling action is performed preliminarily during the adhesive layer formation process itself. The lower molecular weight resin automatically flows into the gap before heat treatment, preventing cavity formation in advance and eliminating the need for separate gap filling operations.
Solution Approach 2:
The adhesive layer uses a composite material system combining resins of different molecular weights. This composite structure enables the material to simultaneously achieve complete gap filling (improving reliability) and maintain structural integrity, resolving the contradiction between reliability and manufacturing precision.
3Manufacturing precision
If the adhesive layer uses multiple resin types with different molecular weights, then gap filling improves, but device complexity increases
Solution Approach 1:
Multiple resin types with different molecular weights are merged into a single adhesive layer formulation. This combining approach achieves complete gap filling through the lower molecular weight resin's flowability while maintaining relatively simple processing, as all resins are applied together in one step rather than requiring multiple separate operations.
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
The solution effectively reduces the size of cavities and enhances the reliability of the semiconductor package by minimizing pressure-induced damage during heat treatments, improving the package's moisture absorption reflow reliability.
Implementation Method 1
The first adhesive layer is provided above a first surface of the substrate and includes a plurality of types of resins having different molecular weights and a filler
Data Source
AI summary
A semiconductor device includes a substrate, a first adhesive layer, a first semiconductor chip, and a second adhesive layer. The first adhesive layer is provided above a first surface of the substrate and includes a plurality of types of resins having different molecular weights and a filler. The first semiconductor chip is provided above the first adhesive layer. The second adhesive layer is provided in at least a part of a first region between the substrate and the first adhesive layer, and the second adhesive layer includes at least one type of resins among the plurality of types of resins having a molecular weight smaller than a molecular weight of other types of resins among the plurality of types of resins, and a filler having a lower concentration than that of the first adhesive layer.