Spin Etching Control for Wafer Radial Etch Distribution
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Solution Overview
Problem
Existing substrate processing methods struggle to precisely control the etching amount distribution in the diametrical direction during spin etching, especially at the central portion of the wafer, due to centrifugal forces and lack of precise control mechanisms.
Innovation Solution
A substrate processing method that involves etching a surface of the substrate by supplying an etching liquid while rotating the substrate and reciprocating the etching liquid supply in a diametrical direction. This method uses a prediction model based on learning data to predict the etching amount distribution, employing equations that account for rotation speed, scan speed, scan width, and non-discharge time to optimize etching conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spin etching is performed with conventional liquid supply methods, then the etching process can be completed, but the etching amount distribution in the diametrical direction cannot be precisely controlled
Solution Approach 1:
The patent applies the dynamics principle by making the liquid supply position movable instead of fixed. The liquid supply device reciprocates in the diametrical direction while the substrate rotates, creating dynamic control over where etching liquid is applied. This enables precise control of etching amount distribution by adjusting the reciprocation range and speed, directly resolving the contradiction between precision and operational simplicity.
Solution Approach 2:
The patent employs parameter changes by varying multiple process parameters including reciprocation speed, reciprocation range, rotation speed, and liquid supply rate. By independently controlling these parameters, the system can achieve desired etching amount distributions without complex mechanical structures, thus improving precision while maintaining ease of operation through software-controlled parameter adjustment.
2Manufacturing precision
If the liquid supply position is fixed during spin etching, then the apparatus structure is simple, but the etching amount at the central portion cannot be precisely controlled
Solution Approach 1:
The liquid supply mechanism is made dynamic by implementing reciprocation motion in the diametrical direction. This allows the liquid supply position to be precisely controlled during etching, enabling accurate control of etching amounts at the central portion and other regions without requiring complex multi-axis positioning systems, thus balancing precision with device simplicity.
Solution Approach 2:
The liquid supply device serves multiple functions: it supplies etching liquid, controls etching amount distribution through reciprocation, and can be positioned to treat different regions of the substrate. This multi-functionality achieves precise central portion control without adding separate specialized devices, reducing overall system complexity.
3Productivity
If trial-and-error methods are used to control etching amount distribution, then the process can be adjusted, but productivity is reduced due to repeated measurements and adjustments
Solution Approach 1:
The patent applies preliminary action by using prediction models to calculate optimal liquid supply conditions before actual etching. The system predicts etching amount distributions based on desired outcomes and determines the necessary reciprocation parameters in advance, eliminating the need for repeated trial-and-error measurements and significantly improving productivity while maintaining measurement precision through controlled prediction-verification cycles.
Solution Approach 2:
The system implements feedback by measuring actual etching amounts and using this information to refine prediction models. This feedback mechanism allows the system to learn from measurements rather than requiring repeated trial-and-error, improving both productivity and measurement precision by reducing the number of iterative adjustments needed.
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 method allows for accurate prediction and control of the etching amount distribution in the diametrical direction, improving the precision of surface shape control after etching and reducing the reliance on trial-and-error methods.
Implementation Method 1
existing substrate processing methods struggle to precisely control the etching amount distribution in the diametrical direction during spin etching, especially at the central portion of the wafer, due to centrifugal forces
Data Source
AI summary
Predicting of an etching amount distribution in a diametrical direction of an etching target includes: acquiring learning data including etching amount distribution when a surface of the etching target is etched under multiple different etching conditions; and predicting the etching amount distribution under prediction target etching conditions from following equations (1) to (6) by using the learning data.ERscan(R)=ERref(R)×Ratioscan(R)(1)Ratioscan(R)=b0×exp(b1×T+b2)+C(2)b0=f(S,V)(3)b1=f(S,V)(4)b2=f(S,V)(5)T=(L-R)/V(6)