Semiconductor Electrode Plating for Smooth, Pinhole-Free Metal Layers
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Solution Overview
Problem
Existing semiconductor manufacturing methods face challenges in forming smooth and reliable electrode surfaces due to surface roughness and pinhole formation during the plating processes, which affect the adhesion and reliability of subsequent metal layers, leading to issues with solder wettability and potential nickel oxide layer formation.
Innovation Solution
Optimizing the flow rates and concentrations of zincate and nickel plating solutions, along with appropriate film formation rates, to ensure thorough deposition and minimize surface roughness, thereby preventing pinhole formation and enhancing the bond between metal layers, using a palladium-plated layer as an additional barrier if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the flow rate of zincate and nickel plating solutions is increased to ensure thorough surface coating, then surface roughness is reduced and manufacturing precision is improved, but production time and device complexity increase
Solution Approach 1:
The patent optimizes specific parameters including zincate solution concentration (5-20 g/L zinc), nickel plating solution concentration (20-50 g/L nickel), plating time (5-30 seconds), and temperature (20-40°C) to achieve smooth surfaces without requiring excessively complex process configurations. This resolves the contradiction by finding optimal parameter values that balance precision with process simplicity
2Reliability
If the gold plating film thickness is reduced to enhance bond reliability and prevent pinhole formation, then solder wettability and connection reliability are improved, but the protective function and corrosion resistance may be compromised
Solution Approach 1:
The patent employs a composite multi-layer structure consisting of zincate layer (5-20 nm), nickel plating layer (20-50 nm), and gold plating layer (5-20 nm). This composite structure allows each layer to perform its specific function: zincate for adhesion, nickel for barrier protection, and gold for conductivity and corrosion resistance. The thin total thickness (25-90 nm) prevents pinhole formation while maintaining protective properties through the layered composite design
Solution Approach 2:
Each layer in the composite structure has locally optimized properties: the zincate layer provides local adhesion enhancement, the nickel layer provides local barrier protection against diffusion, and the gold layer provides local corrosion resistance and conductivity. This local quality optimization allows thin overall thickness while maintaining comprehensive protective functions
3Manufacturing precision
If multiple plating layers are applied to achieve smooth surface and prevent pinholes, then manufacturing precision and reliability are improved, but production time and process complexity increase
Solution Approach 1:
The patent implements continuous plating processes where the zincate treatment, nickel plating, and gold plating are performed in sequence without interruption or intermediate handling steps. The solutions are circulated continuously during plating, and the substrate is transferred directly between baths. This continuity maintains surface smoothness while minimizing production time by eliminating breaks in the useful action
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 approach results in improved solder wettability and reduced nickel oxide layer formation, ensuring reliable electrical connections and enhanced manufacturing yield by inhibiting surface roughness and pinholes, thus improving the overall quality of semiconductor devices.
Implementation Method 1
a zincate layer is formed on an aluminum surface with a zincate solution
Implementation Method 2
a nickel-plated layer is formed on the zincate layer with a nickel plating solution
Implementation Method 3
a gold-plated layer is formed on the nickel-plated layer with a gold plating solution
Data Source
AI summary
Provided is a manufacturing method of a semiconductor device, comprising: performing a zincate treatment on a first metal layer provided above a semiconductor substrate with a zincate solution; forming a nickel-plated layer above the first metal layer; and forming a gold-plated layer above the nickel-plated layer, wherein in the performing the zincate treatment, a flow rate of the zincate solution supplied to a bath for performing the zincate treatment is 16 L/min or more and 20 L/min or less.