Substrate Positioning Error Correction in Plasma Processing
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Solution Overview
Problem
In substrate processing, positional errors during wafer transfer in plasma etching and CVD processes lead to inaccurate substrate placement, potential damage, and difficulties in analyzing process data, due to errors in driving systems and deformation of equipment under vacuum conditions, and existing detection methods are inadequate for correcting these errors.
Innovation Solution
A substrate processing apparatus with a detecting head that optically detects the outer periphery of the substrate and placing table to calculate positional errors and correct the substrate's position, using a driving mechanism to move the detecting head between detection and evacuation positions, and issuing warnings for positional errors outside an allowable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a carrying apparatus is used to transfer substrates in a multi-chamber system, then substrate transfer capability is improved, but positional accuracy deteriorates due to error accumulation from driving system stretch and chamber deformation under vacuum
Solution Approach 1:
The patent applies preliminary action by detecting the substrate position and calculating positional errors before the substrate is placed on the placing table. The system performs detection and correction operations in advance during the transfer process, allowing the substrate to be repositioned accurately before final placement, thereby preventing the accumulation of transfer errors from affecting the final positioning accuracy
Solution Approach 2:
The patent implements feedback by using a detecting head to continuously monitor the substrate position during transfer, calculating the deviation from the target position, and using this information to correct the substrate position. This closed-loop feedback mechanism compensates for the positional errors that accumulate in multi-chamber systems, maintaining high positioning accuracy despite the complexity of the transfer process
2Productivity
If substrate position is not corrected, then processing speed is maintained, but substrate damage risk increases due to improper mounting on the placing table
Solution Approach 1:
The system performs position detection and correction as a preliminary action before the substrate is mounted on the placing table. By detecting the substrate position during transfer and calculating the positional error in advance, the system can correct the position before final placement, ensuring reliable mounting without requiring rework or causing damage later in the process
Solution Approach 2:
The patent replaces purely mechanical transfer mechanisms with an optical detection and calculation system that provides real-time position feedback. This substitution allows for non-contact position measurement and intelligent correction, improving mounting reliability without adding mechanical complexity that would slow down the transfer process
3Measurement precision
If a detecting head is installed in the processing vessel, then substrate position detection capability is improved, but device complexity increases
Solution Approach 1:
The detecting head is designed with multi-functionality, serving both as a position detection device and as part of the overall control system architecture. The same detecting head structure is used across different chambers and positions, providing a universal solution that reduces overall system complexity despite the added detection capability. The detecting head integrates multiple functions including optical detection, signal processing, and communication with the central control system
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
Ensures accurate substrate placement, prevents damage from improper mounting, and enhances data analysis by correcting positional errors, reducing the risk of substrate loss during transfer and maintaining equipment integrity.
Implementation Method 1
a detecting head adapted to optically detect the outer periphery of the substrate
Data Source
AI summary
A substrate processing apparatus is provided, which can place a substrate in a correct position, even though a positional error occurs between the substrate carried in a processing vessel and a placing table. This substrate processing apparatus can take a necessary action immediately against a positional error of the substrate generated when the substrate is separated from the placing table after completion of a process. The plasma apparatus 1 includes a processing vessel 11, lifting pins 34 provided in the processing vessel 11, and a detecting head 22. A wafer W is carried into the processing vessel 11 from the exterior of the processing vessel 11 by using a carrying apparatus 6, and is stopped in a transferring position above the lifting pins 34. Thereafter, the detecting head 22 is moved from an evacuation position to a detection position, so as to obtain positional error information between a current position in which the wafer W is currently held and a programmed position in which the transfer of the wafer W is to be carried out. Based on the positional error information, the transferring position of the wafer W is corrected by using the carrying apparatus 6, such that an amount of the positional error between the current position W and the programmed position is within an allowable range.