Glass Core Package Substrates for Fine-Pitch Die Tiling
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Solution Overview
Problem
The handling of thin glass cores in electronic substrate manufacturing requires significant capital expenditure due to the need for retooling existing infrastructure, and existing bridge die architectures face challenges with high cumulative bump thickness variation and yield issues in fine die-to-die interconnections.
Innovation Solution
A glass core stitching process is employed, where the substrate is fabricated on a carrier, and a thin glass core is attached using a bond film followed by a self-aligned dry etch process, enabling monolithic FLI first and solderless monolithic bridge die face down architectures, reducing thickness and improving yield and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin glass core is used to enable fine die-to-die interconnections, then manufacturing precision and signal loss are improved, but handling difficulty and capital expenditure increase significantly
Solution Approach 1:
A release layer is introduced as an intermediary between the thin glass core and the carrier during fabrication. This release layer enables easy detachment of the thin glass core from the carrier after patterning, solving the handling difficulty without requiring new manufacturing infrastructure. The release layer acts as a temporary support that can be cleanly removed, allowing the thin glass core to be transferred to the substrate package.
2Productivity
If bridge die architecture is used for high-density interconnects, then integration density is improved, but cumulative bump thickness variation increases leading to lower yields
Solution Approach 1:
The patent changes the material parameter from conventional epoxy core to glass core, which has inherently lower total thickness variation (TTV). This material parameter change enables finer bump pitches (25 microns or lower) with reduced cumulative bump thickness variation, improving yield while maintaining high integration density through bridge die architecture.
3Ease of manufacture
If conventional epoxy core is used, then ease of manufacture is maintained, but signal loss and total thickness variation increase
Solution Approach 1:
The patent changes the core material from conventional epoxy to glass, exploiting the superior electrical properties of glass including lower dielectric loss and lower total thickness variation. This parameter change reduces signal losses for high-speed signals while maintaining manufacturing simplicity through the use of standard glass processing techniques on existing substrate manufacturing infrastructure.
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 allows for reduced capital expenditure, easier handling of thin glass cores, improved yield with reduced warpage, and lower total thickness variation, enhancing electrical performance by eliminating solder connections and enabling finer bump pitches.
Implementation Method 1
a bond film followed by a self-aligned dry etch process
Implementation Method 2
self-aligned dry etch process
Data Source
AI summary
Embodiments disclosed herein include a package substrate. In an embodiment, the package substrate comprises a core with a first surface and a second surface, where the core comprises glass. In an embodiment, a first via is through the core, where the first via comprise a conductive material, and a film over the first surface of the core, where the film is an adhesive. In an embodiment, a second via is through the film, where the second via comprises a conductive material, where the second via contacts the first via. In an embodiment, a centerline of the second via is aligned with a centerline of the first via. In an embodiment, a buildup layer is over the film.