Graphene-Coated Package Substrate for Copper Oxidation Control
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Solution Overview
Problem
Conventional semiconductor package substrates face issues with oxide film formation due to copper exposure, leading to poor wire bonding strength and increased costs from precious metal plating or thick organic film coatings.
Innovation Solution
A semiconductor package substrate with a graphene layer as an antioxidant film, formed on a metal catalyst layer surrounding the die pad and lead portions, prevents oxidation and enhances bonding wire strength without the need for precious metal plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precious metal plating is performed to prevent oxide film formation, then oxidation resistance is improved, but manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent replaces expensive precious metal plating with a thin organic film coating that provides sufficient oxidation protection for the specific application period. This disposable-like approach uses a cost-effective material (organic film) instead of valuable materials (precious metals), significantly reducing manufacturing costs while maintaining adequate protection during the wire bonding process and initial operation period.
Solution Approach 2:
The patent optimizes the organic film thickness to a specific range (50-200 nm) that balances oxidation protection with wire bonding performance. By precisely controlling the film thickness parameter, the solution achieves sufficient antioxidant period without creating a thick barrier that would interfere with subsequent wire bonding or solder bump processes, thus simplifying the overall manufacturing process.
2Reliability
If thick organic film coating is performed to obtain antioxidant period, then oxidation resistance is improved, but wire bonding process becomes difficult
Solution Approach 1:
The patent precisely controls the organic film thickness within the range of 50-200 nm, which is thick enough to provide sufficient oxidation protection (antioxidant period) but thin enough to allow wire bonding and solder bump processes to proceed smoothly. This parameter optimization resolves the contradiction by finding the optimal thickness that satisfies both protection and processability requirements.
Solution Approach 2:
The organic film is applied selectively on specific regions of the semiconductor package substrate, particularly on areas requiring oxidation protection while maintaining wire bonding accessibility. This localized coating approach ensures that the film provides protection where needed without creating unnecessary barriers in bonding regions, facilitating smooth manufacturing processes.
3Device complexity
If no antioxidant film is applied, then manufacturing cost is reduced and process is simplified, but oxide film forms on copper substrate
Solution Approach 1:
The patent introduces a thin organic film as an intermediary layer between the copper substrate and the oxidizing environment. This intermediate film acts as a barrier that prevents direct contact between oxygen and the copper surface, thereby preventing oxide film formation without requiring complex precious metal plating processes. The organic film serves as a simple yet effective mediator that protects the substrate while maintaining process 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
The graphene layer effectively prevents oxidation, ensuring reliable bonding with a wire pull strength of 3.5 gf to 5 gf and reducing costs by eliminating the need for precious metal plating, while maintaining smooth bonding processes.
Implementation Method 1
forming a graphene layer on the metal catalyst layer
Implementation Method 2
metal catalyst layer arranged on the base substrate
Implementation Method 3
graphene layer as an antioxidant film... prevents the formation of the oxide film
Data Source
AI summary
The disclosure provides a semiconductor package substrate, a semiconductor package, and a method of manufacturing the semiconductor package substrate. An embodiment of the disclosure provides a semiconductor package substrate including a base substrate including a die pad portion and a lead portion, a metal catalyst layer arranged on the base substrate, and a graphene layer arranged on the metal catalyst layer.