Wiring Substrate Insulating Stopper for Copper Exposure
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Solution Overview
Problem
Conventional semiconductor integrated circuit devices face issues with hole depth variation during manufacturing, leading to incomplete exposure of copper connecting portions and increased manufacturing steps due to the need for polyimide films to prevent electrical continuity.
Innovation Solution
A wiring substrate with a conductive connecting portion and an insulating portion surrounding the connecting portion, which functions as a polishing stopper to ensure complete exposure and prevent electrical continuity, eliminating the need for polyimide films and reducing manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing methods are used with hole depth variation, then manufacturing process is simpler, but copper connecting portion exposure is incomplete and reliability decreases
Solution Approach 1:
An insulating film is formed in advance around the side surface of the hole before copper plating. This preliminary insulating structure ensures that even with hole depth variation, the copper connecting portion will be completely exposed during grinding without causing electrical continuity with the substrate, thus improving reliability while accommodating manufacturing precision variations.
Solution Approach 2:
The insulating film acts as an intermediary layer between the copper connecting portion and the substrate. It prevents direct electrical contact between the copper and substrate, eliminating the harmful effect of incomplete exposure and ensuring reliable electrical isolation even when grinding depth varies.
2Reliability
If polyimide films are added to prevent electrical continuity, then reliability improves, but manufacturing steps increase
Solution Approach 1:
The insulating film formation is merged with the existing copper connecting portion formation process. The same insulating film that provides electrical isolation also serves as a barrier during copper plating and grinding operations, combining multiple functions into a single structure and eliminating the need for separate polyimide film steps.
Solution Approach 2:
The insulating film performs multiple functions: it provides electrical isolation between copper and substrate, prevents copper diffusion during plating, and serves as a grinding stopper to control exposure depth. This multi-functionality eliminates the need for additional polyimide films, reducing manufacturing steps while maintaining reliability.
3Reliability
If excessive grinding is performed to ensure copper exposure, then connecting reliability improves, but substrate erosion and dishing increase
Solution Approach 1:
The insulating film is formed around the hole side surface before copper plating and grinding. During grinding, this insulating film acts as a protective barrier and depth reference, allowing the copper connecting portion to be completely exposed while preventing excessive substrate removal, thus maintaining surface quality.
Solution Approach 2:
The insulating film surrounding the hole provides a cushioning effect during grinding operations. It protects the substrate from excessive erosion and dishing by serving as a mechanical barrier and depth indicator, ensuring that grinding stops at the appropriate depth once the insulating film is removed.
Data Source
AI summary
There is provided a wiring substrate for connecting a mounting board on one surface thereof and mounting an integrated circuit chip on the opposite surface to the surface. The wiring substrate has a conductive connecting portion penetrating the substrate for connecting to at least a portion of a wiring layer of the integrated circuit chip, with the portion of a wiring layer formed on the substrate, and an insulating portion formed at a lateral side of the connecting portion for surrounding the connecting portion via a portion of the wiring substrate.