Thin Glass Core Panels With Local Thinning for Fine-Pitch IC Packaging
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Solution Overview
Problem
Existing IC packaging technologies face challenges in scaling feature sizes below 5 μm and enabling larger substrate sizes due to limitations in package substrate materials, particularly in transitioning from fiberglass resin cores to glass cores, which require thinner glass cores to reduce conductive via depth and increase lateral pitch.
Innovation Solution
A method involving patterning recesses in glass cores, thinning specific regions, and building up metallization features to create a thin glass core substrate, allowing for reduced feature sizes and increased density of conductive vias, using techniques such as laser-assisted etching and semi-additive processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If glass core thickness is reduced, then via depth is reduced and lateral pitch can be scaled down, but glass core mechanical strength and panel integrity are compromised
Solution Approach 1:
The patent applies local quality by creating a non-uniform glass core structure with different thickness regions: a first thickness in the center region and a second greater thickness at the periphery. This allows the central region to support fine-pitch vias while the peripheral region provides mechanical strength and structural integrity to the entire panel.
Solution Approach 2:
The glass core is segmented into functionally distinct regions based on thickness: a thinned central region for high-density via formation and a thicker peripheral region for structural support. This segmentation resolves the contradiction by assigning different thickness characteristics to different functional zones within the same glass core.
2Productivity
If glass core thickness is reduced, then conductive via depth is reduced and density increased, but panel reconstitution and handling become difficult
Solution Approach 1:
The patent implements local quality through selective thickness reduction, maintaining thin glass in the via formation region for high via density while preserving greater thickness at edges and periphery for easier panel handling, reconstitution, and mechanical support during manufacturing processes.
3Quantity of substance
If feature sizes are scaled down below 5 μm, then I/O count and density are increased, but manufacturing precision and control become more challenging
Solution Approach 1:
The patent applies parameter changes by modifying the glass core thickness parameter to enable finer feature formation. The thinned central region allows for precise formation of sub-5 μm features and high-density vias, while the overall glass core dimensions and peripheral thickness remain optimized for manufacturing handling and precision control.
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
Enables the fabrication of IC packages with conductive vias at pitches less than 1 μm and supports larger substrate sizes, enhancing electrical connectivity and mechanical strength while maintaining panel integrity.
Implementation Method 1
laser-assisted etching
Data Source
AI summary
Thin glass cores for integrated circuit (IC) packages. Recesses in a glass core may be selectively etched into a frontside and/or backside of the glass core to locally reduce the thickness of glass. A dielectric material may be applied over the glass to backfill the recesses. The glass may then be further thinned from a same side as the recess to reduce the thickness of regions outside of the recesses. Alternatively, the glass may then be further thinned from a side of the glass opposite the recess to reduce the thickness of regions outside of the recesses and also remove the lesser thickness of glass remaining at the location of the recess. Panels comprising the thin glass core may then be built-up with routing metallization and assembled with IC die.