Vertical Wafer Holder Structure for Notch-Tolerant CMP Transfer
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Solution Overview
Problem
The presence of notches on semiconductor wafers leads to unstable placement and skewing during Chemical Mechanical Planarization (CMP) processes, affecting subsequent wafer transfer and requiring accurate notch alignment, which complicates the handling and storage of wafers.
Innovation Solution
A standing wafer holder with a base unit featuring a first and second arc-shaped concave surface and corresponding acting surfaces that work together to support wafers vertically, allowing for stable placement and transfer without requiring precise notch alignment, and can be adjusted to accommodate different wafer sizes and specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wafers are placed horizontally in the holder, then the wafer placement space is increased, but the space utilization is reduced and robot arm operation becomes more difficult
Solution Approach 1:
The patent transitions from horizontal wafer placement to vertical placement by utilizing the vertical dimension. The holder is designed with arc-shaped concave surfaces that accommodate wafers in a vertical orientation, effectively using three-dimensional space more efficiently and facilitating robot arm access from the top.
Solution Approach 2:
The patent inverts the conventional horizontal placement approach by implementing vertical wafer placement. This inversion allows the robot arm to easily place and retrieve wafers from the top of the holder, improving operational efficiency and space utilization.
2Reliability
If wafers with notches are placed in conventional holders, then the notches cause unstable placement and skewing, but adjusting the holder to accommodate notches increases device complexity
Solution Approach 1:
The patent employs arc-shaped concave surfaces in the holder design that naturally accommodate the circular geometry of wafers with notches. The curved surfaces provide stable support without requiring precise alignment with the notch position, thereby maintaining placement stability while avoiding complex adjustment mechanisms.
Solution Approach 2:
The holder design incorporates asymmetric arc-shaped surfaces that can accommodate the asymmetric notch feature of wafers. The arc-shaped concave surfaces are designed to contact the wafer at multiple points, providing stable support regardless of the notch position, thus eliminating the need for complex alignment adjustments.
3Manufacturing precision
If the holder is designed to precisely locate notches, then wafer placement accuracy is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The arc-shaped concave surfaces are designed with radii that match the wafer curvature, allowing the holder to accommodate wafers with notches at various positions without requiring precise notch alignment. This curved surface design simplifies manufacturing compared to precision-machined features that would be needed to locate notches accurately.
Solution Approach 2:
The holder design creates a universal support structure that can accommodate wafers regardless of notch position or orientation. The arc-shaped surfaces provide multi-point contact that stabilizes the wafer without requiring the holder to be precisely adjusted for each wafer's specific notch location, thereby simplifying manufacturing while maintaining placement accuracy.
Data Source
AI summary
Disclosed is a standing wafer holder comprising at least one base unit which comprises first and second wafer seats. The first wafer seat top is provided with a first arc-shaped concave surface, a first acting surface is formed on a side, facing the second wafer seat, of the first wafer seat and corresponds to an area where the first arc-shaped concave surface is located, and the first acting surface is shaped like a left half of Y. The second wafer seat top is provided with a second arc-shaped concave surface, a second acting surface is formed on a side, facing the first wafer seat, of the second wafer seat and corresponds to an area where the second arc-shaped concave surface is located, and the second acting surface is shaped like a right half of Y. The first and second acting surfaces work together to support a wafer vertically.