Photomask Substrate Processing Control for Overlay Error Correction
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Solution Overview
Problem
Existing substrate processing technologies face challenges in accurately correcting overlay errors between circuit patterns on wafers due to constraints imposed by pre-existing flaws or hazes on photomasks, limiting the ability to adjust applied stress and transmittance effectively.
Innovation Solution
A substrate processing control apparatus that includes a position information acquiring module and a position determining module to precisely control the formation of pixels on a photomask substrate, allowing for adjustment of stress and transmittance by specifying positions in both the X-Y plane and Z-direction, thereby enabling more flexible correction of overlay errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flaws or hazes are formed in the substrate to correct overlay error, then overlay error correction capability is improved, but the ability to form additional flaws or hazes at already processed positions is constrained
Solution Approach 1:
The patent introduces the Z-direction (depth dimension) in addition to the conventional X-Y plane for pixel formation. By specifying positions in three-dimensional space (X, Y, Z), the system can form pixels at different depths within the substrate, enabling multiple correction layers without interfering with each other. This dimensional expansion resolves the constraint where only single-layer corrections were possible at each X-Y position.
Solution Approach 2:
The patent implements a nested structure where multiple pixel layers are formed at different Z-depths within the same substrate volume. Inner pixels are formed at deeper Z positions while outer pixels are at shallower positions, allowing hierarchical arrangement of correction elements. This nesting enables cumulative correction capability where each layer contributes to overall overlay error correction without blocking previous corrections.
2Manufacturing precision
If multiple pixels are formed at the same X-Y position, then correction precision is improved, but existing pixels may be damaged
Solution Approach 1:
By utilizing the Z-direction for position differentiation, the system can form multiple pixels at the same X-Y coordinates but at different depths. The position specifying unit distinguishes between pixels using three-dimensional coordinates (X, Y, Z), allowing safe formation of multiple pixels at overlapping planar positions without collision or damage to existing pixels.
3Device complexity
If the position specifying unit only controls X-Y plane positions, then device complexity is reduced, but the ability to control stress and transmittance precisely is limited
Solution Approach 1:
The position specifying unit is enhanced to handle three-dimensional position specification (X, Y, Z) instead of only two-dimensional. This additional dimensional control enables precise positioning of pixels in depth, allowing independent adjustment of stress and transmittance properties at different Z-levels while maintaining overall system manageability through systematic coordinate-based control.
Data Source
AI summary
In one embodiment, a substrate processing control apparatus includes a position information acquiring module configured to acquire information about a position of a first pattern that is formed in a substrate for a photomask to change an applied stress to the substrate or a transmittance of the substrate. The apparatus further includes a position determining module configured to determine, in accordance with the information about the position of the first pattern, a position of a second pattern to be formed in the substrate to change the applied stress to the substrate or the transmittance of the substrate.