Rotation Axis Determination for Semiconductor Wafer Orientation Error
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Solution Overview
Problem
The existing methods for determining the orientation error of contact points on semiconductor wafers are time-consuming and costly due to the need for precise alignment and multiple rotational positions, which introduces inaccuracies and requires extensive pre-alignment.
Innovation Solution
Determining the axis of rotation of the substrate or substrate holding means before measuring contact point positions, allowing for the calculation of opposite positions in a second rotational position, thereby eliminating the need for pre-alignment and simplifying the process by using optical detection means and a reference labeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate is rotated by 180 degrees to determine orientation errors of contact points, then measurement accuracy is improved by canceling out optical detection inaccuracies, but the process time increases due to the need for pre-alignment in each rotational position
Solution Approach 1:
The axis of rotation is determined in advance before the substrate rotation takes place. This preliminary determination of the axis position allows the system to calculate where contact points will be located after rotation, eliminating the need for time-consuming pre-alignment operations in each rotational position while maintaining measurement accuracy
Solution Approach 2:
The invention introduces a calculation dimension by using the determined axis of rotation to compute the positions of contact points in the second rotational position. Instead of physically re-aligning the optical detection means, the system calculates the new positions based on the axis location, thereby eliminating the pre-alignment step while preserving measurement precision
2Measurement precision
If multiple rotational positions are used to detect contact point positions, then orientation error determination accuracy is improved, but device complexity increases due to the need for precise rotational positioning and pre-alignment mechanisms
Solution Approach 1:
The invention replaces the mechanical pre-alignment system with a calculation-based approach. Instead of using complex mechanical mechanisms to pre-align the optical detection means for each rotational position, the system determines the axis of rotation and calculates the contact point positions mathematically, thereby reducing device complexity while maintaining measurement accuracy
Solution Approach 2:
The axis of rotation serves as an intermediary element that mediates between the substrate and the optical detection means. By determining the axis position first, the system can use this intermediate information to calculate contact point positions without requiring complex mechanical pre-alignment mechanisms, thus reducing device complexity
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 significantly accelerates the determination of orientation errors by allowing the X-Y positions of contact points to be detected in a single rotation, reducing the time and cost associated with the process while ensuring precise alignment.
Implementation Method 1
detecting, in each case with optical positional detection means, a position of the axis of rotation
Data Source
AI summary
In a system having a substrate holding means for holding a substrate, wherein the substrate holding means is rotatable about an axis of rotation that is perpendicular to an X-Y coordinate system, a method for determining position of the axis of rotation in the X-Y coordinate system, comprising the steps of:providing a reference labeling on the substrate holding means or on the substrate;determining a first X-Y reference position RP of a reference labeling on the substrate holding means or on the substrate by means of optical positional detecting means that is fixed relative to the X-Y coordinate system,rotating the substrate holding means by a defined angle of rotation R around the axis of rotation,determining by means of said fixed optical positional detecting means a second X-Y reference position RP′ of the reference labeling that is changed by the rotation, andcalculating the X-Y position of the axis of rotation in the substrate.