Shifted Chip Stacking With Columnar Electrodes to Prevent Cracking
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Solution Overview
Problem
Semiconductor chips are prone to cracking when connecting the interconnect substrate and semiconductor chips with columnar electrodes.
Innovation Solution
Forming columnar electrodes on the interconnect substrate instead of the semiconductor chips, using materials like Cu or CuPd, and employing a shifted mounting technique for semiconductor chips with metal bumps and resin layers to stabilize the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connection methods are used to connect semiconductor chips to interconnect substrate, then the connection process is simple, but cracking occurs in semiconductor chips under thermal stress
Solution Approach 1:
The columnar electrodes are formed on the interconnect substrate before the semiconductor chips are mounted. This preliminary formation of electrodes allows for precise positioning and reduces stress concentration during subsequent thermal cycling, preventing cracking in the chips while maintaining a relatively simple overall process flow.
Solution Approach 2:
The molded resin layer acts as an intermediary material that fills the spaces between the columnar electrodes and semiconductor chips, providing mechanical support and stress distribution. This intermediary structure protects the chips from direct stress concentration at the connection points, thereby preventing cracking under thermal stress.
2Reliability
If columnar electrodes with molded resin layer are used to connect chips, then cracking is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The columnar electrodes and molded resin layer are integrated into a unified connection structure where the resin is formed to simultaneously fill spaces, secure electrodes, and protect chip joints. This merging of functions into a single manufacturing step (forming the molded resin layer) achieves reliable crack prevention without adding excessive process complexity.
Data Source
AI summary
A semiconductor device includes: an interconnect substrate including a plurality of interconnect layers; a first semiconductor chip disposed over the interconnect substrate; a second semiconductor chip disposed over the first semiconductor chip in a shifted manner and including a plurality of metal bumps on a surface of the second semiconductor chip facing the interconnect substrate; and a plurality of columnar electrodes connecting the interconnect structure to the metal bumps.