Redistribution Pad Opening Structure to Prevent Insulation Peeling
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Solution Overview
Problem
Existing semiconductor packages and wiring substrates face issues with peeling or detachment of the outer insulation layer from the interconnection pad, leading to crack initiation or propagation at the inner insulation layer, which reduces reliability and increases defects.
Innovation Solution
The semiconductor package and wiring substrate include a redistribution portion with an interconnection pad that has a first region and a second region outside the first region with an opening, and an outer insulation layer that covers the second region and fills at least a part of the opening, enhancing adhesion and preventing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer insulation layer covers the edge region of the pad in a solder mask defined structure, then the adhesion force between the pad and the insulation layer is improved, but the insulation layer may be easily peeled from the pad and cracks may be initiated
Solution Approach 1:
The interconnection pad is divided into a first region and a second region, with the outer insulation layer covering only the second region. This segmentation allows the pad to maintain electrical functionality in the first region while providing insulation and stress relief in the second region, preventing peeling at the insulation layer edges.
Solution Approach 2:
The outer insulation layer is selectively applied to cover the edge region (second region) of the pad rather than the entire pad surface. This local quality approach provides insulation where needed at the edges while leaving the central first region exposed for electrical connection, optimizing both adhesion and peeling resistance.
2Stress or pressure
If the outer insulation layer covers the edge region of the pad, then resistance to stress applied to the pad is improved, but peeling and crack initiation occur at the insulation layer
Solution Approach 1:
The pad structure is segmented into a first region (exposed) and a second region (covered by outer insulation layer). This segmentation allows stress to be distributed and absorbed at the edges where the insulation layer is present, while the exposed first region maintains electrical functionality without being constrained by the insulation layer, preventing crack initiation.
Solution Approach 2:
The outer insulation layer acts as an intermediary element that provides stress resistance at the pad edges. By covering only the second region (edge region) and not the entire pad, it mediates between the need for stress resistance and the need to prevent peeling and cracking, allowing stress absorption without compromising reliability.
Data Source
AI summary
A semiconductor package according to an embodiment includes a semiconductor chip, and a redistribution portion electrically connected to the semiconductor chip. The redistribution portion includes an inner insulation layer, an interconnection pad, and an outer insulation layer. The interconnection pad is on the inner insulation layer and includes a first region and a second region outside the first region and having an opening. The outer insulation layer includes a first portion on the second region of the interconnection pad and a second portion filling at least a part of the opening.