Clam Shell Two-Pin Wafer Holder for Low-Stress Metal Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing wafer holders used in metal plating processes often result in wafer breakage and scrap due to misalignment and excessive stress caused by multiple contact pins, leading to high voltage arcing and reverse plating issues, which are not effectively addressed by increasing the number of pin contacts.
Innovation Solution
A clam shell two-pin wafer holder design with a hinge connecting the base and lid, featuring two diagonally positioned contact pins that align with corresponding contact points on the wafer, reducing stress and improving alignment control during the plating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If four contact pins are used in the holder, then current delivery to the wafer is achieved, but wafer breakage and misalignment occur due to excessive stress and alignment difficulty
Solution Approach 1:
The patent extracts two contact pins from the four-pin holder configuration, reducing the number of pins from four to two. This reduction eliminates excessive stress on the wafer while maintaining sufficient current delivery capability through the remaining two pins positioned at opposite corners of the wafer
Solution Approach 2:
The patent segments the holder into two main components: a base piece with a wafer supporting surface and a lid piece with contact pins. This segmentation allows independent optimization of each component - the base provides stable wafer support while the lid provides controlled current delivery through fewer pins
2Reliability
If four contact pins are used in the holder, then current delivery to the wafer is achieved, but alignment challenges occur during clamping
Solution Approach 1:
The patent positions the two contact pins at diagonally opposite corners of the wafer rather than at adjacent corners or symmetrically distributed positions. This asymmetric diagonal placement creates natural alignment references that simplify the alignment process during clamping while maintaining electrical connectivity
Solution Approach 2:
The patent merges the alignment function and electrical contact function into the same two pin locations. The diagonally positioned pins serve dual purposes: they provide structural alignment references during clamping and simultaneously deliver current to the wafer, eliminating the need for separate alignment mechanisms
3Reliability
If multiple contact pins are used, then current delivery is achieved, but high voltage arcing and reverse plating scrap occur
Solution Approach 1:
The patent removes two contact pins from the holder, reducing the total from four to two. This extraction eliminates potential sources of misalignment and arcing while maintaining sufficient current delivery capability through the remaining two properly positioned pins
Solution Approach 2:
The patent changes the spatial parameters of the contact pins by positioning them at diagonally opposite corners rather than adjacent corners. This parameter change optimizes the electrical field distribution, reducing arcing and reverse plating issues while maintaining effective current delivery
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 two-pin configuration reduces wafer breakage and scrap by 70%, increases die yield by 0.2%, and allows for better pin placement and alignment, minimizing electrical shorts and ergonomic challenges, while also enabling die recovery from previously obscured areas.
Implementation Method 1
Metal electroplating is accomplished by delivering current to the metallized contact points 152 and 254 of a wafer surface (seed metal) through the four contact pins 122, acting as conductors pressed against the contact points of the wafer
Implementation Method 2
the metal pins 122 of the holder top piece 120 must be aligned with the four contact points 152 of the wafer after the wafer has been placed in the base piece 112 of the holder 100
Implementation Method 3
A single hinge pivotally connects the lid to the base, the hinge primarily aligning the two contact pins with two corresponding contact points on a wafer when the lid is closed against the base
Implementation Method 4
The base piece 110 and the top piece 120 are clamped together with four clamps 140 around a circumference of the holder 100
Data Source
AI summary
A clam shell wafer holder includes a base and a lid pivotally connected with the base by an integral hinge. The base includes a rotatable wafer support, and the lid includes a universal frame and a pin holder attachment spaced inwardly from the frame. Only two contact pins are formed in a wafer-facing surface of the pin holder attachment. The contact pins are manually aligned with and contact two points on a wafer when the lid is closed against the base. A method for holding a wafer for plating is provided using the disclosed holder apparatus.