Adjustment Lens for Photolithography Image Size Control
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Solution Overview
Problem
Existing photolithography projection systems face challenges in accurately controlling the relative image size of a projected substrate pattern due to environmental changes and the complexity of coordinating multiple lens groups, which can lead to image blurring and deterioration.
Innovation Solution
A photolithography apparatus with a projection system that uses a single adjustment lens movable along its optical axis, positioned such that the apparent mask pattern appears at a distance twice the focal length of the lens, allowing for precise control of image size without significantly affecting the image plane position, thereby simplifying and robustifying the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple lens groups are used to control magnification, then the image size control capability is improved, but the system complexity increases and manufacturing precision requirements become more stringent
Solution Approach 1:
The patent extracts the magnification control function from the complex multi-lens group system and implements it using a single movable lens. This simplifies the projection system by removing unnecessary lens groups while maintaining the essential image size adjustment capability through the movement of one lens along the optical axis.
Solution Approach 2:
The single movable lens in the patent performs multiple functions: it controls magnification, maintains image plane position, and ensures telecentricity. This universal lens replaces what would traditionally require multiple specialized lens groups, reducing system complexity while preserving adaptability.
2Adaptability or versatility
If multiple lens groups are positioned symmetrically about a stop, then magnification control is achieved, but the system becomes sensitive to temperature fluctuations and manufacturing variations
Solution Approach 1:
The patent removes the vulnerable multi-lens group configuration and retains only the essential magnification control function through a single movable lens. This eliminates the sensitivity to temperature fluctuations and manufacturing variations that arise from having multiple lens groups that must maintain precise relative positions.
Solution Approach 2:
The patent changes the control parameter from the relative positions of multiple lens groups to the position of a single lens along the optical axis. This single-parameter control system is inherently more stable and less sensitive to environmental changes and manufacturing tolerances.
3Adaptability or versatility
If lens groups are moved to adjust magnification, then image size control is improved, but the image plane position shifts causing blurring
Solution Approach 1:
The patent implements a dynamic system where a single lens moves along the optical axis to adjust magnification while maintaining the image plane position. The lens can be positioned at specific locations (including twice the focal length from the mask) to achieve different magnifications without shifting the image plane, thus avoiding blurring.
Solution Approach 2:
The patent changes the control approach by using the position of a single lens relative to the mask and image plane. By positioning the lens at specific distances (such as twice the focal length), the system achieves magnification control while maintaining sharp focus, eliminating the blurring problem associated with traditional multi-lens group adjustments.
4Adaptability or versatility
If symmetric lens groups are used, then magnification adjustment is possible, but the manufacturing precision requirements increase due to the need for identical lens groups
Solution Approach 1:
The patent extracts the magnification control function from the pair of symmetric lens groups and implements it with a single lens. This eliminates the need to manufacture and assemble identical lens groups, significantly easing the manufacturing process while maintaining full magnification adjustment capability through the movement of the single lens.
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 accurate and versatile control of the relative image size with minimal influence on the image plane, reducing the need for complex adjustments and manufacturing identical lens groups, resulting in a more robust and compact projection system.
Implementation Method 1
The projection system comprises an adjustment lens moveable in a range encompassing a central position for controlling a relative image size of the projected substrate pattern by a relative position of the adjustment lens
Data Source
AI summary
The present disclosure concerns a photolithography apparatus (100) and method for controlling relative image size (S1/S0) of a projected substrate pattern (W). A projection system (10) is arranged for projecting an image of a mask pattern (M) as the substrate pattern (W) onto a substrate (6), wherein the projection system (10) comprises an adjustment lens (13) moveable in a range (Xmin,Xmax) encompassing a central position (X0) for controlling a relative image size (S1/S0). The projection system (10) is arranged to project the mask pattern (M) onto the adjustment lens (13) such that, when the adjustment lens (13) is positioned at the central position (X0), an apparent mask pattern (M′) from a point of view of the adjustment lens (13) appears to be at a distance (2*F) from the adjustment lens (13) that is twice a focal length (F) of the adjustment lens (13).