Glass Core Substrate with Low-Phosphorus Nickel Plating
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Solution Overview
Problem
Glass core substrates used in semiconductor modules are prone to cracking due to high phosphorus content in nickel plating layers, which affects their durability and electrical characteristics.
Innovation Solution
A glass core substrate with a nickel plating layer having a phosphorus content of 5 mass% or less, where a titanium layer is disposed between the nickel plating layer and the glass plate, and a copper layer is between the titanium and nickel layers, to enhance adhesion and reduce cracking susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nickel plating layer with high phosphorus content is used, then adhesion is improved, but cracking susceptibility increases
Solution Approach 1:
The invention divides the adhesion function into two separate layers: a titanium layer that provides strong adhesion to glass and a nickel layer with low phosphorus content that provides electrical conductivity. This segmentation allows each layer to optimize its specific function without the trade-off present in high-phosphorus nickel layers, thereby reducing cracking susceptibility while maintaining adhesion.
Solution Approach 2:
The invention changes the phosphorus content parameter of the nickel plating layer from high (conventional) to low (5 mass% or less). This parameter change reduces the cracking susceptibility of the nickel layer while the titanium layer compensates for any adhesion loss, achieving both low cracking susceptibility and sufficient adhesion.
2Reliability
If a titanium layer and copper layer are added between nickel and glass, then adhesion is improved and cracking is reduced, but device complexity increases
Solution Approach 1:
The titanium layer serves multiple functions: it provides strong adhesion to the glass substrate, acts as a diffusion barrier, and contributes to electrical conductivity. The copper layer provides both electrical conductivity and acts as a stress relief layer. This multi-functionality reduces the need for additional specialized layers, thereby limiting the increase in device complexity.
Solution Approach 2:
The copper layer acts as an intermediary between the titanium layer and the low-phosphorus nickel layer, providing a transition zone that manages stress and facilitates both mechanical and electrical connection. This intermediary structure resolves the complexity issue by creating a functional buffer zone rather than directly connecting dissimilar materials.
3Reliability
If phosphorus content in nickel plating is reduced to 5 mass% or less, then cracking susceptibility is reduced, but adhesion may be compromised
Solution Approach 1:
The titanium layer serves as an intermediary that provides the strong adhesion to glass that the low-phosphorus nickel layer cannot provide on its own. This mediator allows the nickel layer to maintain low phosphorus content (reducing cracking) while the titanium layer ensures sufficient overall adhesion to the substrate.
Solution Approach 2:
The invention creates a composite plating structure combining titanium and nickel layers, where each material contributes its superior properties: titanium provides adhesion to glass and corrosion resistance, while low-phosphorus nickel provides electrical conductivity and reduced cracking susceptibility. This composite structure achieves properties neither material could provide alone.
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 modified glass core substrate is less prone to cracking and exhibits improved electrical characteristics, with the reduced phosphorus content in the nickel plating layers contributing to better adhesion and manufacturing efficiency.
Implementation Method 1
forming a titanium layer on a first main surface of the glass plate by sputtering or vapor phase deposition
Implementation Method 2
forming a titanium layer on a first main surface of the glass plate by sputtering or vapor phase deposition
Implementation Method 3
forming a copper layer on the titanium layer by sputtering
Implementation Method 4
forming a nickel plating layer with a phosphorus content of 5 mass% or less on at least a first main surface of a glass plate by electroless plating
Implementation Method 5
forming a copper plating layer to cover a portion of the nickel plating layer by electrolytic plating
Implementation Method 6
etching the other portion of the nickel plating layer by using an acid as an etching agent to form a conductor pattern
Data Source
Figure 1~2
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Figure 5~6
AI summary
There is provided a technique for making a glass core substrate which is less prone to cracking. A core substrate 1 of the present invention includes a glass plate 10 and a first conductor pattern 20 provided on a first main surface of the glass plate 10. The first conductor pattern 20 includes a first nickel plating layer 210 that is provided on the first main surface of the glass plate 10 and has a phosphorus content of 5 mass% or less and a first copper plating layer 22 that is provided on the first nickel plating layer 210.