Semiconductor Pad Plating Layout for Small-Pad Gold Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electroless plating method for forming OPM electrodes in semiconductor devices often results in non-adhesion of the gold film on smaller pads like the kelvin and drain pads, leading to defective bonding and increased manufacturing costs due to the concentration of electrons on larger pads, such as the source pad, which reduces the supply to smaller pads and affects the reliability of the semiconductor device.
Innovation Solution
A semiconductor device manufacturing method involving the sequential formation of plating layers on pads using a sputtering method for seed layers and electrolytic plating for subsequent layers, where the uppermost surface of the source pad has a non-noble metal and the smaller pads have a noble metal plating layer, specifically copper, palladium, and gold, to improve adhesion and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electroless plating method is used to form OPM electrodes on all pads, then the number of manufacturing steps is reduced and manufacturing cost is decreased, but non-adhesion of the gold film occurs on smaller pads like kelvin and drain pads
Solution Approach 1:
The patent applies different plating methods to different pads based on their specific requirements. Larger pads (source pad) use electroless plating for cost efficiency, while smaller pads (kelvin and drain pads) use electrolytic plating to ensure adequate gold film adhesion. This local differentiation resolves the contradiction by optimizing each pad's plating process according to its area and adhesion needs.
Solution Approach 2:
The patent segments the pad group into two categories: larger pads and smaller pads. This segmentation allows the application of different plating methodologies tailored to each category's characteristics, preventing the uniform application of electroless plating that causes adhesion failures on small pads while maintaining its cost benefits on large pads.
2Ease of manufacture
If the electroless plating method is used to form OPM electrodes, then manufacturing cost is decreased, but non-adhesion of the gold film occurs leading to defective bonding
Solution Approach 1:
The patent implements local quality control by applying electrolytic plating specifically to smaller pads where adhesion is critical for bonding reliability, while using cost-effective electroless plating on larger pads. This targeted approach maintains overall cost efficiency while ensuring bonding quality where it matters most.
Solution Approach 2:
The patent changes the plating method parameter from electroless to electrolytic for smaller pads, fundamentally altering the deposition mechanism to provide better adhesion control. This parameter change enables reliable bonding on small pads without compromising the cost benefits of electroless plating on larger pads.
3Quantity of substance
If electrons are concentrated on the large source pad during plating, then the source pad receives sufficient plating material, but the smaller kelvin and drain pads receive insufficient electrons leading to non-adhesion
Solution Approach 1:
The patent addresses the uneven electron distribution by applying electrolytic plating to smaller pads, which provides controlled electron supply and better adhesion. This local intervention compensates for the electron concentration imbalance that occurs during electroless plating, ensuring adequate gold film formation on small pads without disrupting the overall plating process.
Solution Approach 2:
The patent introduces electrolytic plating as an intermediary process for smaller pads, acting as a mediator that ensures adequate electron supply and proper gold film adhesion. This intermediary approach bridges the gap caused by electron concentration on large pads, preventing adhesion failures on small pads.
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 the reliability of semiconductor devices by preventing non-adhesion of the gold film on smaller pads and reduces manufacturing costs by optimizing the plating process, thereby improving yield and reducing the need for costly noble metal usage on larger pads.
Implementation Method 1
A semiconductor device manufacturing method involving the sequential formation of plating layers on pads using a sputtering method for seed layers
Implementation Method 2
electrolytic plating for subsequent layers
Data Source
AI summary
An interlayer insulating film is formed on an upper surface of a semiconductor substrate. A source pad and a kelvin pad, a gate pad, and a drain pad each having a smaller plane area than a plane area of the source pad are formed on the interlayer insulating film. A first plating layer is formed on the source pad. A second plating layer is formed on each of the kelvin pad, the gate pad, and the drain pad. A material of an uppermost surface of the first plating layer is a metal other than a noble metal, and a material of an uppermost surface of the second plating layer is a noble metal.