Glass Interposer Bridge With Self-Aligned TGVs for Simpler Packaging
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Solution Overview
Problem
As the number of interconnect bridges in microelectronic assemblies increases, the cost and yield of embedding them suffer due to high cumulative Bump Thickness Variation (BTV) and complexity in approaches like silicon bridges within glass interposers, which require precise cavity drilling and encapsulation, especially with non-flat surfaces.
Innovation Solution
The solution involves an interconnect bridge with through glass vias (TGVs) that eliminates the need for cavity creation, allowing for a simpler architecture and solderless attachment by pressing the bridge onto the underlying buildup layer, using a glass material with TGVs extending across the bridge layer to connect conductive structures between buildup layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If silicon bridge structures with cavities are used for advanced interconnect regimes, then signal routing capability is improved, but manufacturing complexity and cost increase due to precise cavity drilling and encapsulation requirements
Solution Approach 1:
The invention extracts and eliminates the cavity structure from the interconnect bridge design. Instead of embedding the bridge in a cavity formed in the buildup layer, the bridge is formed as a standalone structure with through-glass vias that extend through its entire thickness, removing the need for complex cavity drilling and encapsulation processes while maintaining signal routing functionality
Solution Approach 2:
The invention inverts the traditional approach by forming the interconnect bridge first and then creating through-glass vias through it, rather than forming cavities in the buildup layer and then embedding bridges. This reversal of the process sequence simplifies manufacturing by eliminating the need for precise cavity alignment and encapsulation
2Adaptability or versatility
If multiple interconnect bridges are embedded in the package substrate, then bandwidth density is improved, but yield decreases due to high cumulative Bump Thickness Variation
Solution Approach 1:
The invention removes the cavity encapsulation step that contributes to Bump Thickness Variation. By forming through-glass vias that extend through the bridge structure itself rather than embedding bridges in cavities, the cumulative thickness variation is reduced, improving yield when multiple bridges are used to achieve high bandwidth density
3Strength
If cavity drilling and encapsulation are performed for interconnect bridge embedding, then structural support is improved, but alignment precision requirements increase
Solution Approach 1:
The invention inverts the process by forming the bridge structure first and then creating through-glass vias through it, rather than forming cavities first and embedding bridges. This eliminates the need for precise alignment between cavities and bridges, as the vias are formed through the bridge itself using photolithography and etching processes that provide inherent alignment
Solution Approach 2:
The through-glass via structure serves itself by extending through the entire bridge thickness and providing both electrical connection and structural support. The via walls provide mechanical reinforcement to the bridge structure, eliminating the need for separate cavity encapsulation for structural support
Data Source
AI summary
A microelectronic structure, a semiconductor package including the structure, an IC device assembly including the structure, and a method of making the structure. The microelectronic structure includes: a first buildup layer and a second buildup layer including respective first and second electrically conductive structures; and a bridge layer including a glass material extending across a width thereof, the bridge layer between the first buildup layer and the second buildup layer and comprising: an interconnect bridge including third electrically conductive structures coupling a first set of the first electrically conductive structures to a second set of the first electrically conductive structures. Through glass vias (TGVs) extending from a top surface to a bottom surface of the bridge layer, the TGVs coupling a third set of the first electrically conductive structures to at least some of the second electrically conductive structures.