Exposure Apparatus Resist Tilt Correction Shift Compensation
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Solution Overview
Problem
Conventional semiconductor exposure techniques face challenges in achieving high accuracy due to tilt corrections in wafer tables, leading to shift errors during exposure, especially when dealing with thick resist layers and varying wafer surface tilts, which affect alignment and overlay precision.
Innovation Solution
An exposure apparatus and method that utilize an off-axis alignment detection system to measure the distance and tilt of the resist surface relative to the alignment mark, calculating a correction value to adjust the table position and correct for shift errors, ensuring accurate alignment and exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tilt correction is performed to reduce the tilt of the resist surface during exposure, then the flatness and exposure quality are improved, but a shift error occurs between the alignment position and the actual exposure position
Solution Approach 1:
The system performs alignment measurement before tilt correction, records the alignment mark position, then performs tilt correction for exposure. The recorded alignment position is used to calculate the shift error and compensate for it during exposure, ensuring both alignment accuracy and exposure quality are maintained
Solution Approach 2:
The system uses the alignment measurement data as feedback to calculate the shift error caused by tilt correction, and applies this feedback to adjust the exposure position, creating a closed-loop control system that maintains accuracy throughout the process
2Length of moving object
If the distance from the alignment mark to the resist surface is large, then the tilt of the resist surface increases, but the alignment accuracy degrades due to the tilt
Solution Approach 1:
The system changes the measurement parameters by recording not only the position of the alignment mark but also the tilt angle of the resist surface. This additional parameter information allows for calculation and compensation of the shift error, maintaining alignment accuracy even when the distance is large
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 enables high-accuracy exposure by precisely correcting shift errors, improving overlay accuracy and reducing manufacturing costs by maintaining the flatness of substrates and minimizing additional processing steps.
Implementation Method 1
as has been reported conventionally, in a measurement technique such as an interferometer, a shift occurs in position to be exposed
Data Source
AI summary
An exposure apparatus exposes a resist on a substrate to light via an optical system. The exposure apparatus includes: a table configured to position the substrate at an exposure position upon holding the substrate; an obtaining unit configured to obtain a distance from an alignment mark formed on the substrate to a resist surface, and a tilt of the resist surface; and a control unit configured to calculate a correction value for correcting a shift in exposure position, that occurs upon tilt correction of the table, so as to reduce the tilt of the resist surface, using the distance and the tilt, and control a position of the table in accordance with the correction value.