Glass Core TGV Structure Without Buffer-Layer Current Pinch
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Solution Overview
Problem
The use of glass cores in electronic packages with through glass vias (TGVs) is limited by the narrow via extension through the buffer layer, which restricts current flow and reduces power density due to the narrower geometry, creating a current pinch point.
Innovation Solution
The implementation of wider vias through the buffer layers, matching the width of the TGVs, eliminates the current pinch point by aligning the via centerlines with the TGVs and using a single patterning process to maintain equal widths, thereby enhancing electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a buffer layer is added to enable copper deposition on glass core, then copper deposition is enabled and stress is mitigated, but the via width is reduced creating a current pinch point
Solution Approach 1:
The via structure is segmented into multiple portions: a first portion through the buffer layer with width equal to the TGV, a second portion through the glass core matching the TGV width, and a third portion through the buffer layer also matching the TGV width. This segmentation ensures each segment maintains optimal current carrying capacity while the buffer layer still enables copper deposition.
Solution Approach 2:
The via width parameter is changed from the conventional narrowed geometry to a uniform width that matches the TGV diameter throughout all portions. This parameter change eliminates the current pinch point while maintaining the buffer layer's functionality for copper deposition and stress mitigation.
2Ease of manufacture
If the via extension is narrower than the TGV to fit through the buffer layer, then the via can pass through the buffer layer, but the maximum current is limited
Solution Approach 1:
The via is divided into distinct segments (first, second, and third portions) where each segment's dimensions are optimized for its specific function. The first and third portions through the buffer layer maintain TGV-matching width for current capacity, while the structure remains manufacturable through standard patterning processes.
Solution Approach 2:
The critical parameter change is maintaining the via width equal to the TGV diameter throughout all buffer layer portions, rather than reducing it. This parameter change directly increases power density by eliminating current restriction while preserving manufacturability.
3Reliability
If the via width is maintained equal to TGV width through buffer layers, then current flow is improved, but manufacturing complexity increases
Solution Approach 1:
The via structure serves multiple functions simultaneously: it provides electrical connection through the glass core, maintains optimal current carrying capacity through uniform width, and interfaces properly with buffer layers for copper deposition. The single patterning process creates all via portions in one operation, reducing manufacturing steps despite the multi-functional requirements.
Solution Approach 2:
The via maintains homogeneous width throughout all portions (first, second, and third portions) equal to the TGV diameter. This homogeneity simplifies the patterning process as it requires maintaining a constant width specification, and eliminates the need for complex width transitions or tapers that would increase manufacturing complexity.
Data Source
AI summary
Embodiments disclosed herein include package substrates. In an embodiment, the package substrate comprises a core, where the core comprises glass. In an embodiment, a first layer is under the core, a second layer is over the core, and a via is through the core, the first layer, and the second layer. In an embodiment a width of the via through the core is equal to a width of the via through the first layer and the second layer. In an embodiment, the package substrate further comprises a first pad under the via, and a second pad over the via.