Double-Lined Through-Glass Vias for CTE Stress Buffering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of through-glass vias (TGVs) in glass cores is challenged by significant CTE mismatch-induced stresses between glass and metal materials, leading to potential cracking and degradation due to thermal cycling, which compromises the structural integrity of glass cores.
Innovation Solution
Implementing double liners in TGVs, with a first liner having a higher modulus and lower CTE in contact with glass and a second liner with a lower modulus and higher CTE, to act as a buffer layer and reduce stress, thereby mitigating CTE mismatch-induced stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-glass vias (TGVs) filled with metals are used in glass cores, then electrical connectivity and thermal management are improved, but glass is highly susceptible to damage due to mechanical and thermal stresses from CTE mismatch
Solution Approach 1:
A liner material is introduced as an intermediary layer between the glass core and the metal fill in TGVs. This liner has a CTE that is lower than the metal but higher than the glass, creating a gradient that reduces the stress concentration at the glass-metal interface. The liner acts as a buffer that absorbs thermal expansion differences, preventing crack initiation and propagation in the glass core while maintaining electrical connectivity.
2Strength
If glass cores are used instead of organic resin-based cores, then rigidity, thermal properties, and electrical insulation are improved, but glass is highly susceptible to damage due to mechanical and thermal stresses
Solution Approach 1:
The CTE parameter of the TGV structure is modified by introducing a liner layer with intermediate thermal expansion properties. This changes the overall thermal expansion behavior of the TGV, making it more compatible with the glass core and reducing thermal stress during temperature cycling. The liner's specific CTE value is selected to optimize the stress distribution between glass and metal components.
3Productivity
If multiple IC dies are integrated in a single IC package, then capacity and functionality are increased, but package warpage occurs due to out of plane deformation from materials with different material properties
Solution Approach 1:
The liner is applied locally at the TGV interfaces where stress concentration occurs, rather than throughout the entire package structure. This localized modification addresses the warpage issue at critical stress points while maintaining the overall package design and integration capacity. The liner's presence at the glass-metal interface locally compensates for CTE mismatch, reducing differential expansion that causes warpage.
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
The use of double liners in TGVs reduces stress on glass cores, enhancing the structural integrity and reliability of microelectronic assemblies, allowing for reliable integration of multiple layers with reduced warpage and increased design flexibility.
Implementation Method 1
significant CTE mismatch-induced stresses between glass and metal materials, leading to potential cracking and degradation due to thermal cycling
Data Source
AI summary
A microelectronic assembly according to an embodiment of the present disclosure may include a glass core (e.g., a layer of glass or a glass structure) having a first face and a second face opposite the first face; a through-glass via (TGV) in the layer of glass, the TGV extending from the first face towards the second face and comprising a conductive material; a first liner in the TGV, between the conductive material and the layer of glass; and a second liner in the TGV, between the conductive material and the layer of glass, wherein the first liner is between the layer of glass and the second liner, and wherein a modulus of the first liner is higher than a modulus of the second liner.