Microlithography Mask With Extended Pattern Areas
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Solution Overview
Problem
Conventional microlithography scanning exposure methods suffer from low throughput due to inefficient radiation usage and prolonged scanning operations, as the reticle masking blades are often closed after each exposure, leading to significant light loss and incomplete exposure of substrate areas.
Innovation Solution
A novel mask design for microlithography with extended patterned areas and a modified scanning exposure method that allows for continuous exposure of multiple substrate areas in a single scanning operation, utilizing a reticle-masking device that remains open to maximize radiation usage and split the exposure of substrate areas across multiple scanning directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the reticle masking blades are closed after each exposure, then the exposure precision is improved, but the light loss increases and throughput decreases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the reticle masking blades in an open state before the scanning operation begins. This allows the radiation to continuously illuminate the patterned area throughout the entire scanning process, eliminating the need to close and reopen blades during exposure. The blades remain open as a preliminary prepared state, enabling continuous light transmission and maximizing radiation usage efficiency.
2Manufacturing precision
If the reticle masking blades are closed after each exposure, then the exposure precision is improved, but the throughput decreases
Solution Approach 1:
The patent implements continuity of useful action by maintaining the reticle masking blades in a continuously open state during the entire scanning operation. This eliminates interruptions in the exposure process, allowing the radiation to continuously illuminate and expose the substrate areas throughout the scanning motion. The useful action of exposing the substrate continues without interruption, thereby maximizing throughput while maintaining precision.
3Productivity
If the entire pattern is exposed in a single scanning operation, then the throughput is improved, but the radiation usage efficiency decreases due to light loss
Solution Approach 1:
The patent applies dynamics by making the reticle masking blades movable and controllable throughout the scanning operation. The blades are dynamically positioned to remain open during the entire exposure process, adapting to the continuous motion of the scanning system. This dynamic configuration allows the system to optimize both throughput and radiation usage efficiency by eliminating unnecessary blade movements that would cause light loss.
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 significantly increases throughput by allowing more efficient use of radiation, ensuring uniform exposure of substrate areas with reduced light loss and enabling partial exposure of areas in one scanning operation, followed by complementary exposure in subsequent operations, thereby enhancing the overall efficiency of the microlithography process.
Implementation Method 1
The radiation modified by the pattern passes through the projection objective, which forms an image of the pattern in the image plane of the projection objective
Data Source
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Figure 3~3C
AI summary
A mask for microlithography comprises a substrate (SUB); a first pattern area (PA1) on the substrate, the first pattern area comprising a first pattern (PAT1) extending over a first length (L1) in a mask scanning direction and a first width (W1) in a direction perpendicular to the mask scan direction; and a second pattern area (PA2) on the substrate adjacent to the first pattern area in the mask scanning direction, the second pattern area comprising a second pattern (PAT2) extending over a second length (L2) in the mask scanning direction and a second width (W2) identical to the first width in the direction perpendicular to the mask scan direction. The second length (L2) is smaller than the first length (L1) and the second pattern is identical to a corresponding portion of the first pattern, where the corresponding portion is offset relative to the second pattern by the first length (L1) in the mask scan direction and has a length (CPL) identical to the second length (L2). Scanning exposure methods with increased throughput are possible when this type of mask is used.