Substrate Holder Tilting for Edge Position Measurement Error Correction
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Solution Overview
Problem
Current methods for measuring the positions of structures on substrates are limited by systematic errors introduced by substrate topology and coordinate measuring machine geometry, leading to inaccuracies in edge measurement.
Innovation Solution
A method involving measuring positions in X, Y, and Z coordinates, tilting the substrate to adjust its position, and determining correction values based on deviations to minimize lateral position deviations, utilizing a coordinate measuring machine with a substrate holder that allows tilting and supports the substrate on three points defining a plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate is measured in a fixed position without tilting, then the measurement process is simple and fast, but systematic errors occur due to substrate topology and coordinate measuring machine geometry
Solution Approach 1:
The substrate holder is made tiltable about an axis parallel to the X/Y plane, allowing the substrate to be dynamically adjusted between a first position (flat measurement) and a second tilted position (topography measurement). This dynamic positioning enables the measurement system to adapt to different measurement requirements, resolving the contradiction between measurement simplicity and accuracy by providing multiple measurable states.
Solution Approach 2:
The invention introduces a rotational degree of freedom (tilting about an axis parallel to the X/Y plane) to the substrate holder. This adds a new dimension of movement beyond the standard X/Y translation, enabling the substrate to be positioned at different angles relative to the coordinate measuring machine. This dimensional expansion allows measurement of substrate topography and determination of correction values without compromising measurement simplicity.
2Measurement precision
If correction values are determined through multiple measurements at tilted and non-tilted positions, then measurement accuracy is improved, but the measurement time and process complexity increase
Solution Approach 1:
The substrate topography and systematic errors are measured and correction values are determined in advance, before the actual edge position measurements are performed. By pre-characterizing the substrate and holder geometry through measurements at different tilted positions, the correction values are established beforehand and can be applied to subsequent measurements, reducing the time required for each individual measurement while maintaining high accuracy.
Solution Approach 2:
The measurement system uses the substrate itself and its inherent topography to generate the correction values. By measuring the substrate at multiple positions and orientations, the system self-characterizes the systematic errors introduced by both the substrate topology and the coordinate measuring machine geometry, eliminating the need for external calibration standards or additional equipment.
Data Source
AI summary
A method for determining the lateral correction as a function of the substrate topology and/or the geometry of the substrate holder is disclosed. The substrate is placed on a measuring stage traversable in the X coordinate direction and Y coordinate direction, which carries the substrate to be measured. The substrate is supported on at least three support points which define a plane. An apparatus is provided for determining the position of a plurality of positions on the surface of the substrate in the in the X, Y and Z coordinate directions. The substrate is tiltable about an axis parallel to the X/Y plane, to enable the substrate to be measured in a tilted position.