Wiring Substrate Copper Alloy Adhesive Layer Delamination Prevention
Solution Overview
Problem
In multi-layer wiring substrates, such as interposers, the adhesion between copper wiring layers and electrode layers is compromised due to differences in thermal expansion coefficients, leading to potential delamination and loss of electrical connection when subjected to thermal loads.
Innovation Solution
A copper alloy layer is introduced between the electrode and wiring layers, with a tin layer forming convex and concave sections on the electrode surface to enhance adhesion, and a titanium layer is applied over the oxide layer to maintain adhesion with the oxide layer, preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a titanium adhesive layer is formed between the wiring layer and electrode layer to improve adhesion, then the adhesion property between layers is improved, but the thermal expansion mismatch still causes delamination under thermal loads
Solution Approach 1:
The patent changes the material parameter of the adhesive layer from pure titanium to a copper-containing adhesive layer. This material substitution addresses the thermal expansion mismatch issue because copper has a thermal expansion coefficient closer to that of the copper wiring layer and copper electrode, reducing differential thermal stress and preventing delamination while maintaining adhesion.
2Reliability
If a multi-layer structure with adhesive layers is used to ensure electrical connection, then the electrical connectivity is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent merges the adhesive layer formation with the existing copper plating process. The copper-containing adhesive layer is formed using the same electroplating equipment and process that forms the copper wiring and electrode layers, eliminating the need for separate adhesive layer deposition equipment and processes. This integration maintains electrical connection reliability while reducing manufacturing complexity.
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 configuration ensures a stable connection between the electrode and wiring layers while maintaining adhesion between the oxide and titanium layers, preventing delamination and ensuring reliable electrical contact.
Implementation Method 1
a tin layer forming convex and concave sections on the electrode surface to enhance adhesion
Implementation Method 2
a titanium layer is applied over the oxide layer to maintain adhesion with the oxide layer, preventing delamination
Data Source
AI summary
A wiring substrate includes a wiring layer made of copper, an electrode layer made of copper, and an insulating layer arranged adjacent to the electrode layer. The wiring layer is stacked on the electrode layer and the insulating layer. The insulating layer and the wiring layer are stacked with an adhesive layer interposed between the insulating layer and the wiring layer. The electrode layer and the wiring layer are stacked with a copper alloy layer formed adjacent to the adhesive layer and interposed between the electrode layer and the wiring layer.