Glass Package Substrate Stacks for Thermal Stress and Power Delivery
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Solution Overview
Problem
Glass core substrates in integrated circuit packages are prone to seware failures due to defects and thermal expansion mismatches, leading to crack propagation and mechanical instability, which affects signal transmission and power delivery.
Innovation Solution
Implementing multiple distinct glass cores with varying coefficients of thermal expansion (CTE) stacked together, along with a buffer material to absorb stress, and using power delivery interconnects like coaxial magnetic inductor loops and plated magnetic vias to enhance electrical pathways through the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass core substrates are used to provide higher PTH density and lower signal losses, then signal transmission quality is improved, but the substrate becomes prone to seware failures due to thermal expansion mismatches
Solution Approach 1:
The glass core substrate is divided into multiple glass layers with different coefficients of thermal expansion (CTE), creating a gradient structure. This segmentation allows each layer to accommodate different thermal stresses, preventing crack propagation while maintaining the overall structural integrity and signal transmission quality of the substrate.
2Device complexity
If single glass core is used to simplify structure, then manufacturing is easier, but thermal expansion mismatch causes stress concentration and crack propagation
Solution Approach 1:
Different glass layers are assigned different coefficients of thermal expansion to match the CTE of adjacent materials (e.g., PCB, IC chip, solder balls) at specific locations within the substrate. This local customization of material properties ensures thermal compatibility at each interface, distributing stress evenly and preventing crack initiation and propagation.
3Strength
If buffer material is added to absorb stress, then mechanical strength is improved, but device complexity increases
Solution Approach 1:
The substrate employs a composite structure combining multiple glass layers with different CTE values, eliminating the need for separate buffer materials. The gradient glass layering itself acts as the stress-absorbing mechanism, where each layer's thermal expansion properties are tailored to match adjacent materials, thereby absorbing thermal stress inherently while maintaining structural simplicity.
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 reduces stress-induced failures, improves mechanical strength, and maintains high signal integrity and power delivery efficiency by gradient thermal matching and advanced interconnect designs.
Implementation Method 1
a buffer material to absorb stress
Implementation Method 2
multiple distinct glass cores with varying coefficients of thermal expansion (CTE) stacked together
Data Source
AI summary
Systems, apparatus, articles of manufacture, and methods for power delivery through package substrates with stacks of glass layers having different coefficients of thermal expansion are disclosed. An example substrate for an integrated circuit package includes: a first glass layer having a first coefficient of thermal expansion (CTE); a second glass layer having a second CTE, the second CTE different from the first CTE; and a magnetic material lining a first wall of a first opening in the first glass layer and lining a second wall of a second opening in the second glass layer.