Semiconductor Chip Peripheral Thickness Variation for Resin Filling
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Solution Overview
Problem
The reliability of joining between semiconductor chips in multi-chip WL-CSPs is compromised due to difficulties in thoroughly filling sealing resin with high viscosity into the gaps between the chips, leading to incomplete sealing and reduced performance.
Innovation Solution
The design involves a first semiconductor chip with a thinner outer peripheral area and a second semiconductor chip with a step structure, allowing the sealing resin to flow and fill the gap between them more effectively, ensuring complete coverage of the joining member and enhancing the reliability of the chip connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sealing resin with high viscosity is used to fill the gap between semiconductor chips, then the sealing strength is improved, but the filling completeness deteriorates
Solution Approach 1:
The second semiconductor chip is divided into two regions with different thicknesses: a first region (central area) with greater thickness and a second region (peripheral area) with smaller thickness. This segmentation creates varying gap widths between the chips, allowing the high-viscosity sealing resin to flow more effectively into the gap while maintaining adequate filling completeness.
Solution Approach 2:
Different regions of the second semiconductor chip are designed with different thicknesses to create local variations in gap width. The central region has a larger gap that facilitates resin flow, while the peripheral region has a smaller gap that ensures complete filling. This local quality differentiation resolves the contradiction between sealing strength and filling completeness.
2Volume of moving object
If the gap between semiconductor chips is reduced to improve packaging density, then the package size is reduced, but the sealing resin filling becomes more difficult
Solution Approach 1:
The chip structure is segmented into regions with different thicknesses, creating a non-uniform gap distribution. This allows the overall package size to remain compact while providing localized wider gaps that facilitate sealing resin filling, thus resolving the contradiction between small package size and ease of manufacturing.
Solution Approach 2:
Instead of uniformly reducing the gap width in two dimensions, the invention introduces a thickness dimension variation. By making the second chip thinner at its periphery, it creates a three-dimensional gap structure that facilitates resin flow while maintaining compact overall dimensions, thereby resolving the contradiction between package size and filling ease.
3Reliability
If the sealing resin is thoroughly filled into the gap to improve joining reliability, then the joining reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The thickness variation of the second semiconductor chip is predetermined during the chip fabrication process, before the sealing resin filling step. This preliminary action creates favorable conditions for resin flow, ensuring thorough filling and high joining reliability without requiring complex manufacturing processes during assembly.
Solution Approach 2:
The second semiconductor chip is designed with local quality differentiation through varying thickness in different regions. This structural feature passively guides the sealing resin flow, ensuring complete filling in critical areas without requiring complex manufacturing interventions, thus achieving high reliability with minimal manufacturing 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
This approach promotes thorough filling of the sealing resin into the gap, improving the reliability of the chip joining and reducing the risk of incomplete sealing, thereby enhancing the performance and longevity of the multi-chip WL-CSP.
Implementation Method 1
a sealing resin, which is respectively filled between the surface of the first semiconductor chip and the inner peripheral area, and between the surface of the first semiconductor chip and the outer peripheral area
Data Source
AI summary
Reliability of joining between semiconductor chips is improved by promoting filling of a sealing resin into a gap formed between the semiconductor chips.A semiconductor device includes: a first semiconductor chip, which has a plurality of first electrodes on a surface; a second semiconductor chip, which is disposed to be separated by a gap from the surface of the first semiconductor chip, and which includes an inner peripheral area that has a plurality of second electrodes connected to each of the first electrodes on a surface and an outer peripheral area that surrounds the inner peripheral area and has a thickness thinner than the thickness of the inner peripheral area; and a sealing resin, which is respectively filled between the surface of the first semiconductor chip and the inner peripheral area, and between the surface of the first semiconductor chip and the outer peripheral area.