Warpage Release Layer Structure for CTE-Matched Chip Packaging
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Solution Overview
Problem
The challenge in forming reliable chip packages lies in the decreasing feature sizes of semiconductor dies and package components, such as interposer substrates, which complicates the bonding process and increases the risk of warpage due to coefficient of thermal expansion (CTE) mismatches.
Innovation Solution
A warpage release layer structure is formed over the interposer substrate, comprising organic material layers in direct contact with the semiconductor dies and high CTE material layers formed over these organic layers. This structure mitigates CTE mismatches between the semiconductor dies and the interposer substrate, reducing warpage during thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If feature sizes of semiconductor dies and package components are decreased, then integration density is improved, but warpage risk increases due to CTE mismatches
Solution Approach 1:
The patent introduces a warpage release layer structure as an intermediary component between the semiconductor die and the interposer substrate. This layer has a coefficient of thermal expansion (CTE) specifically designed to match that of the semiconductor die, serving as a thermal expansion mediator that reduces stress and prevents warpage during thermal processing and operation.
Solution Approach 2:
The patent changes the CTE parameter of the intermediate layer to match the semiconductor die's CTE. By selecting materials and configuring the layer structure (single layer or multi-layer) with appropriate CTE values, the thermal expansion characteristics of the package structure are modified to reduce differential expansion and resulting warpage.
2Reliability
If warpage release layer structure is added to mitigate CTE mismatches, then package warpage is reduced, but device complexity increases
Solution Approach 1:
The warpage release layer is applied locally only where needed - specifically between the semiconductor die and the interposer substrate - rather than throughout the entire package structure. This targeted approach addresses the CTE mismatch problem at its source while minimizing additional complexity in other parts of the package.
Solution Approach 2:
The warpage release layer structure can be implemented as a composite material system, either as a single layer with specific CTE properties or as multiple layers with different materials and thicknesses. This composite approach allows tuning of the overall CTE to match the semiconductor die while maintaining structural integrity and minimizing added complexity.
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 warpage release layer structure effectively reduces package warpage by compensating for CTE differences, thereby improving the performance and quality of the chip package structure and increasing the process window for flux-dipping and flip chip bonding.
Implementation Method 1
mitigates CTE mismatches between the semiconductor dies and the interposer substrate, reducing warpage during thermal processes
Data Source
AI summary
A chip package structure is provided. The chip package structure includes a first semiconductor die bonded over an interposer substrate and a warpage release layer structure. The chip package structure also includes a first organic material layer covering an upper surface of the first semiconductor die; and a first metal layer covering an upper surface of the first organic material layer. The first metal layer has a planar shape that is the same as a planar shape of the first semiconductor die, as viewed in a top-view perspective.