Wafer Centering Feedback Control for Uniform Edge Etching
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Solution Overview
Problem
The uniformity of edge etching width in semiconductor wafer processing is not adequately controlled, leading to defects and yield loss due to unstable wafer placement and edge contamination, which affects the manufacturing yield of integrated circuits.
Innovation Solution
A wafer centering adjustment apparatus and method that includes a wafer centering system and a wafer edge cleaning effect detection system to measure and correct offset data, ensuring the wafer center aligns with the adsorption platform, and a closed-loop control mechanism to guarantee uniform edge etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wafer placement position depends on transmission position without active centering control, then the device structure remains simple, but the concentricity between wafer and bearing platform cannot be guaranteed, leading to non-uniform edge etching width
Solution Approach 1:
The patent applies preliminary action by performing wafer centering adjustment before the etching process. The centering system measures and corrects the wafer position relative to the bearing platform center in advance, ensuring proper alignment before edge etching begins. This prevents non-uniform etching width that would result from transmission deviations.
Solution Approach 2:
The patent implements feedback control by using a detection system to measure the actual position of the wafer center relative to the bearing platform center. The measured offset information is fed back to the centering adjustment mechanism, which then corrects the position. This closed-loop feedback ensures high concentricity despite variations in transmission positioning.
2Productivity
If edge etching is performed without precise centering control, then the processing speed remains high, but the edge etching width uniformity deteriorates, affecting manufacturing yield
Solution Approach 1:
The system performs preliminary centering adjustment before edge etching to establish proper alignment. By correcting the wafer position in advance relative to the bearing platform, the system ensures that the etching process will produce uniform edge width without requiring slow, iterative adjustments during etching itself.
Solution Approach 2:
The detection system measures the wafer center position and provides feedback to the centering adjustment mechanism. This feedback control enables rapid correction of positioning errors, allowing the system to maintain high processing speed while achieving uniform edge etching width through automated real-time adjustments.
Data Source
AI summary
A wafer centering adjustment method, comprising: before a wafer (4) is etched, a wafer centering system (1) confirms whether the center of the wafer (4) coincides with the center of the first adsorption platform (3), and if not, the wafer centering system (1) corrects the position of the wafer (4). After the etching of the wafer (4) is completed, a wafer edge cleaning effect detection system (2) confirms whether the center of the wafer (4) coincides with the center of the first adsorption platform (3) during the process of etching, and obtains the second offset data. The wafer edge cleaning effect detection system (2) feeds back the second offset data to the wafer centering system (1). Before etching the next wafer, the wafer centering system (1) obtains the first offset data and preforms correction firstly, and then makes a secondary correction to the position of the wafer according to the second offset data obtained after the previous wafer is etched, thereby realizing a closed-loop control of the centering adjustment apparatus. In addition, the degree of coincidence between the center of the wafer and the center of the first adsorption platform is greatly improved by means of the secondary correction, thereby effectively guaranteeing the uniformity of the edge etching width of the wafer.