Roughened Silver Plating Adhesion to Sealing Resin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrates for mounting semiconductor elements face challenges in achieving high adhesion to sealing resin while maintaining a thin plating layer thickness and reducing production costs and time, as conventional methods require thick undercoat plating layers or roughening of noble metal layers, which increase costs and lower productivity.
Innovation Solution
A substrate with columnar terminal portions composed of plating layers featuring a roughened silver plating layer with acicular projections as the outermost layer, where the silver plating layer has a specific crystal structure with a high proportion of a particular crystal direction, enhancing adhesion to sealing resin without the need for thick undercoat layers or costly noble metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick undercoat plating layer is used to enhance adhesion to sealing resin, then adhesion strength is improved, but total plating layer thickness increases and production cost increases
Solution Approach 1:
The invention changes the crystal structure parameters of the silver plating layer by controlling the plating conditions (temperature, current density, bath composition) to obtain a specific crystal orientation where the (100) plane predominates. This parameter change in crystal structure creates acicular projections on the surface that dramatically improve adhesion to sealing resin without requiring increased plating thickness
Solution Approach 2:
The invention creates local quality differences on the silver plating surface by forming acicular projections through controlled crystal growth. These localized protruding structures concentrate adhesion points and provide mechanical interlocking with the sealing resin, achieving high adhesion strength while maintaining thin overall plating thickness
2Strength
If a roughened noble metal layer is used to increase adhesion to sealing resin, then adhesion strength is improved, but production cost increases due to noble metal usage
Solution Approach 1:
The invention replaces expensive noble metals (such as gold or platinum) with a much cheaper silver plating layer. By controlling the crystal structure of silver to form acicular projections, the invention achieves adhesion performance comparable to or exceeding that of noble metals, while dramatically reducing material cost
Solution Approach 2:
The invention changes the physical and chemical parameters of the silver plating process (temperature, current density, bath additives) to control crystal growth and form acicular projections. This parameter optimization allows silver to achieve adhesion properties previously only attainable with expensive noble metals
3Ease of manufacture
If conventional plating methods are used to form smooth silver plating layer, then production process is simple, but adhesion to sealing resin is insufficient
Solution Approach 1:
The invention modifies plating parameters (increasing temperature to 50-80°C, optimizing current density to 3-10 A/dm², adjusting silver ion concentration to 1-10 g/L) to control crystal growth kinetics. These parameter changes transform the plating process from producing smooth surfaces to producing surfaces with acicular projections, dramatically improving adhesion while remaining a straightforward electroplating process
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 substrate achieves remarkable adhesion to sealing resin, reduces processing costs, and minimizes the total thickness of plating layers, while improving productivity by using a thin and smooth undercoat layer and a silver plating layer with acicular projections formed through a specific crystal structure.
Implementation Method 1
columnar terminal portions composed only of plating layers including a silver plating formed as an outermost plating
Implementation Method 2
the roughened silver plating layer has a crystal structure in which the crystal direction <100> occupies a largest proportion among the crystal directions <100>, <110> and <111>
Data Source
AI summary
A substrate for mounting a semiconductor element thereon includes a metal plate and columnar terminal portions composed only of plating layers and formed on one-side surface of the metal plate. The columnar terminal portions include, as an outermost plating layer, a roughened silver plating layer having acicular projections. The roughened silver plating layer has a crystal structure in which the crystal direction <101> occupies a largest proportion among the crystal directions <001>, <111> and <101>. The substrate for mounting a semiconductor element thereon can be manufactured with improved productivity owing to reduction in cost and operation time, and achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer, which are to serve as terminals and the like, to be thin.