Electroless Ni Plating on Au Pads via Pd Catalyst
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Solution Overview
Problem
Existing methods struggle to form electrolessly-plated Ni films on Au electrode pads, leading to low productivity and high costs due to the chemical stability of Au, which makes it difficult for Pd to deposit and form Ni films, necessitating the use of electroplating.
Innovation Solution
A method involving degreasing, etching, pre-dipping, and applying a Pd catalyst at specific temperatures to increase Au reactivity, allowing for the stable deposition of Ni films through electroless plating, thereby forming a semiconductor substrate with electrolessly-plated Ni, Pd, or Au films on Au electrode pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroplating is used to plate Ni on Au electrode pads, then Ni plating can be achieved, but productivity decreases and costs increase due to photoprocessing requirements and individual pad treatment
Solution Approach 1:
The patent replaces the electroplating process (which requires electrical current application, photoprocessing, and individual pad treatment) with an electroless plating process. This substitution eliminates the need for complex electrical equipment, photoprocessing steps, and wiring infrastructure, thereby significantly improving productivity while maintaining reliable Ni plating formation on Au electrode pads.
2Productivity
If electroless Ni plating is attempted on Au electrode pads using conventional methods, then costs and complexity are reduced, but plating fails due to Au's chemical stability preventing Pd deposition
Solution Approach 1:
The patent changes the chemical parameters of the plating solution by introducing specific complexing agents and adjusting solution composition to create conditions where Pd can deposit on Au despite Au's inherent chemical stability. This parameter modification enables the electroless Ni plating process to work effectively on Au electrode pads, achieving both high productivity and reliable film formation.
3Device complexity
If Pd catalyst treatment is applied at room temperature, then process simplicity is maintained, but Pd deposition on Au is insufficient leading to incomplete Ni film formation
Solution Approach 1:
The patent modifies the temperature parameter of the Pd catalyst treatment process, raising it from room temperature to an optimized elevated temperature range. This parameter change enhances Pd deposition efficiency on Au electrode pads without significantly increasing process complexity, as it simply requires temperature control during the existing treatment step, thereby ensuring complete and reliable Ni film formation.
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 enhances productivity and reduces costs by enabling stable electroless Ni plating on Au pads, eliminating the need for electroplating and improving the manufacturing efficiency of semiconductor substrates.
Implementation Method 1
applying a Pd catalyst at specific temperatures to increase Au reactivity, allowing for the stable deposition of Ni films through electroless plating
Implementation Method 2
stable deposition of Ni films through electroless plating
Data Source
AI summary
A semiconductor substrate has, on an Au electrode pad, an electrolessly-plated Ni film/an electrolessly-plated Pd film/an electrolessly-plated Au film or an electrolessly-plated Ni film/an electrolessly-plated Au film and a method of manufacturing the semiconductor substrate by the steps indicated in (1) to (6) below: (1) a degreasing step; (2) an etching step; (3) a pre-dipping step; (4) a Pd catalyst application step; (5) an electroless Ni plating step; (6) an electroless Pd plating step and electroless Au plating step or an electroless Au plating step.