Through-Glass Via Structure to Reduce Glass Core Cracking
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Solution Overview
Problem
The use of glass cores in package substrates for electronic devices can lead to stress concentration points due to differences in coefficients of thermal expansion (CTEs) between copper, glass, and buffer materials, resulting in defects such as cracking and delamination.
Innovation Solution
The implementation of through-glass vias (TGVs) with a specific structure, where the sidewall of the glass core contacts only the copper of the TGV and not the buffer material, reduces stress concentration points and prevents defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass cores are used in package substrates, then electrical coupling between devices is achieved, but stress concentration points occur due to CTE differences between copper, glass, and buffer materials
Solution Approach 1:
The patent introduces an intermediary structure (the specific TGV configuration where copper extends beyond glass surfaces) to mediate between materials with different CTEs. The copper conductive material acts as a buffer zone that absorbs thermal expansion differences, preventing direct stress transmission to the glass core and eliminating stress concentration points at interfaces.
Solution Approach 2:
The patent changes the geometric parameters of the TGV structure, specifically ensuring that copper conductive material extends beyond the glass core surfaces. This parameter modification alters the stress distribution pattern, moving stress concentration points away from the glass core to the copper regions, thereby protecting the glass from cracking.
2Ease of manufacture
If traditional TGV structures are used, then manufacturing is simplified, but defects such as cracking and delamination occur due to stress concentration
Solution Approach 1:
The patent modifies the dimensional parameters of the TGV structure, specifically the extension of copper beyond glass surfaces. This parameter change is integrated into the existing manufacturing process without requiring complex additional steps, maintaining ease of manufacture while achieving defect-free glass cores by eliminating stress concentration points.
3Device complexity
If copper, glass, and buffer materials are in direct contact, then device assembly is simplified, but cracking and delamination defects occur due to CTE mismatch
Solution Approach 1:
The patent uses copper conductive material as an intermediary between glass and buffer materials. The copper extends beyond the glass surfaces, creating a buffer zone that absorbs thermal expansion differences. This intermediary structure prevents direct contact between glass and buffer material at critical interfaces, eliminating stress concentration points while maintaining structural integrity.
Solution Approach 2:
The patent creates a composite material structure where copper, glass, and buffer materials are arranged in a specific configuration. The copper-conductive-material-and-glass-composite structure leverages the properties of each material: copper provides ductility to absorb thermal stress, glass provides electrical insulation and structural support, and buffer materials provide mechanical support. This composite arrangement reduces overall stress on the glass core.
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 effectively reduces the occurrence of defects in the glass core, enhancing the reliability and durability of the package substrate by minimizing stress-induced damage.
Implementation Method 1
differences in coefficients of thermal expansion (CTEs) between copper, glass, and buffer materials, resulting in defects such as cracking and delamination
Data Source
AI summary
Methods and apparatus to reduce cracking in glass cores are disclosed. An example apparatus includes a package substrate comprising a glass core having an opening extending between first and second surfaces of the glass core, the first surface opposite the second surface, and a conductive material, a first portion of the conductive material within the opening, a second portion of the conductive material protruding beyond the first surface of the glass core, a first surface of the first portion in continuity with a second surface of the second portion.