Stress-Compensated Glass Circuit Board Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge lies in achieving high dimensional stability and accuracy in circuit board substrates for miniaturized electronic components, particularly in display applications, where traditional materials like FR-4 and polyimide fail to meet the requirements due to thermal and mechanical instability, leading to issues like warpage, blisters, and delamination.
Innovation Solution
A layered structure comprising a glass or glass ceramic substrate with alternating conductive layers of copper and nickel, where the adhesion layer and seed layer are sputtered coatings, and the conductive layers are electroless plated, providing tensile and compressive stresses to compensate for residual stress, ensuring uniform thickness and adhesion without warpage or delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional substrate materials like FR-4 and polyimide are used, then ease of manufacture is maintained, but dimensional stability and thermal stability deteriorate, causing warpage, blisters, and delamination
Solution Approach 1:
The patent employs a composite layered structure consisting of glass substrate, adhesion layer, seed layer, and alternating conductive layers. This composite structure combines the dimensional stability of glass with the stress-compensating properties of alternating metal layers, resolving the contradiction between manufacturing ease and dimensional stability.
Solution Approach 2:
The patent changes the material parameters by selecting specific metal combinations (copper and nickel) with different stress characteristics. By controlling the thickness ratio and stress parameters of alternating layers, the system achieves overall stress neutrality, eliminating warpage while maintaining manufacturability.
2Stability of the object's composition
If glass or glass ceramic substrate is used, then thermal stability and dimensional stability are improved, but stress management becomes more difficult due to CTE mismatch
Solution Approach 1:
The patent applies local quality by creating alternating layers with different stress properties at specific locations. The copper layers provide compressive stress while nickel layers provide tensile stress, with each layer locally compensating for CTE mismatch effects, thereby managing overall stress without increasing device complexity.
Solution Approach 2:
By changing the thickness parameters of alternating conductive layers, the patent achieves stress balance. The specific thickness ratio between copper and nickel layers is optimized to compensate for CTE mismatch with the glass substrate, transforming the stress management challenge into a controllable parameter optimization problem.
3Reliability
If thick conductive layers are deposited to ensure electrical conductivity, then electrical conductivity is improved, but residual stress increases causing warpage and delamination
Solution Approach 1:
The patent segments the thick conductive layer into multiple thin alternating layers of copper and nickel. This segmentation allows the total conductive thickness to be maintained for electrical conductivity while distributing the stress across multiple interfaces, preventing cumulative stress buildup that would cause warpage or delamination.
Solution Approach 2:
The alternating copper-nickel structure creates a composite conductive system where the different metal materials compensate for each other's stress. This composite approach maintains the electrical conductivity of thick layers while eliminating the residual stress problems associated with single-material thick deposits.
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 solution provides a reliable, stress-free, and uniformly conductive layered structure for glass circuit boards, enhancing the reliability and scalability of electronic devices by minimizing warpage and defects, while maintaining high adhesion and electrical conductivity.
Implementation Method 1
The adhesion layer and the seed layer comprise sputtered coatings
Implementation Method 2
the first conductive layer and the second conductive layer comprise electroless plated coatings
Data Source
AI summary
A layered structure, an article such as circuit board including such a layered structure, and methods of making the same are provided. The layered structure includes a substrate comprising glass or glass ceramic, an adhesion layer disposed on the substrate, a seed layer disposed on the adhesion layer, a first conductive layer disposed on the seed layer, and a second conductive layer disposed on the first conductive layer. The seed layer includes a first metal material and has a first type of stress with respect to the substrate. The first conductive layer includes the first metal material and has a second type of stress with respect to the substrate. The second conductive layer includes a second metal material and has the first type of stress with respect to the substrate. The layered structure may further include additional pairs of alternating layers of the first and the second conductive layers.