Dynamic Alignment Beam Calibration in Plasma Processing
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Solution Overview
Problem
Existing dynamic alignment beam calibration techniques in plasma processing systems face challenges due to potential damage to end effectors and particle contamination, as well as inaccuracies resulting from calibrations performed at atmospheric pressure rather than vacuum conditions, leading to misalignment and decreased yield.
Innovation Solution
An optical imaging method is employed to determine the positional difference between the wafer center and the end effector-defined center, allowing for robot movement compensation to simulate a correctly centered wafer, eliminating the need for mechanical fixtures and enabling calibration under conditions similar to production, thus obtaining a reference dynamic alignment beam pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical fixtures are used to simulate a correctly centered wafer for calibration, then calibration can be performed, but the end effector may be damaged and particle contamination may occur
Solution Approach 1:
The patent replaces the mechanical fixture system with an optical imaging system. Instead of using physical fixtures to simulate a centered wafer, the system uses optical imaging to detect the actual position of the wafer relative to the end effector and calculates positional differences. This substitution eliminates mechanical contact that could damage the end effector or generate particles, while maintaining calibration accuracy through optical measurement.
Solution Approach 2:
The patent creates a virtual model of the correct wafer positioning by capturing optical images of the wafer and end effector, processing these images to determine center positions, and calculating the positional difference. This virtual representation allows calibration to be performed without physical fixtures, avoiding damage and contamination while achieving the same calibration objective.
2Productivity
If calibration is performed at atmospheric pressure, then calibration can be completed, but alignment accuracy decreases due to pressure differences from production conditions
Solution Approach 1:
The patent changes the pressure parameter from atmospheric to vacuum to match production conditions. By performing calibration in vacuum environment, the system ensures that the end effector, chuck, and wafer experience the same pressure conditions during both calibration and production, eliminating alignment errors caused by pressure-induced dimensional changes or positioning shifts.
Solution Approach 2:
The patent performs calibration in advance under the actual production conditions (vacuum pressure) rather than at atmospheric pressure. This preliminary action ensures that the reference DA beam pattern is established under the same environmental conditions that will be present during production, thereby improving the accuracy of subsequent wafer placement operations.
3Object-affected harmful factors
If optical imaging is used to determine positional difference, then end effector damage and particle contamination are avoided, but additional measurement and processing steps are required
Solution Approach 1:
The patent replaces complex mechanical fixture systems with an optical imaging and image processing system. Instead of requiring precise mechanical alignment fixtures, the system uses optical cameras to capture images, processes these images computationally to determine center positions, and calculates positional differences. This substitution reduces mechanical complexity while adding optical and computational elements that are less prone to damage and contamination.
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 ensures accurate dynamic alignment beam calibration without damaging the end effector and reduces particle contamination, providing precise wafer placement and improving production yield by simulating correct centering and calibrating under production-like conditions.
Implementation Method 1
acquire a positional difference, the positional difference being acquired by an optical imaging approach
Data Source
AI summary
A method for performing DA (Dynamic Alignment) beam calibration in a plasma processing system is provided. The method including acquiring a positional difference, the positional difference is acquired using an optical imaging approach. The optical imaging approach comprising of positioning the wafer on the end effector, taking a still image of the wafer on the end effector, processing the still image to ascertain the center of the wafer and an end effector-defined center defined by the end effector, and determining the positional difference between the center of the wafer and the end effector-defined center defined by the end effector. The method also includes centering a wafer with respect to an end effector by compensating for a positional difference between the wafer and the end effector with robot movement compensation. The method including moving the wafer and the end effector through DA beams associated with a plasma processing module. The method also includes obtaining a reference DA beam pattern by recording a break-and-make pattern of the DA beams. The break-and-make pattern occurring as the wafer and the end effector move through the DA beams.