Reticle Layout Rotation for Higher Mask Field Utilization
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Solution Overview
Problem
Current semiconductor integrated circuit manufacturing processes face inefficiencies in optical lithography due to suboptimal mask field utilization, leading to increased shot numbers and reduced exposure efficiency during wafer substrate processing.
Innovation Solution
The method involves determining and adjusting the relative orientation between the device pattern and the mask field of the exposure tool based on mask field utilization, which includes rotating the reticle and wafer substrate to maximize mask field utilization, thereby enhancing exposure efficiency by increasing the exposed area per shot and reducing the number of exposure shots required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional mask field orientation is used without optimization, then the manufacturing process is simple, but the mask field utilization is low leading to increased shot numbers
Solution Approach 1:
The patent applies preliminary action by pre-calculating and determining the optimal relative orientation between the device pattern and mask field before the actual lithography process. The system computes the optimal orientation angle that maximizes mask field utilization, allowing the exposure tool to be configured in advance for maximum efficiency. This pre-planning step eliminates the need for trial-and-error adjustments during production, thereby improving exposure efficiency without adding operational complexity.
Solution Approach 2:
The patent implements parameter changes by optimizing the orientation angle parameter between the device pattern and mask field. By varying this angular parameter to find the optimal value that maximizes mask field utilization, the system achieves higher productivity. The orientation angle becomes a controllable parameter that can be adjusted to improve exposure efficiency, directly addressing the contradiction between productivity and process complexity.
2Area of stationary object
If more exposure shots are used to cover the wafer substrate, then the complete coverage is achieved, but the exposure time and manufacturing cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the mask field utilization through appropriate orientation selection. By changing the relative orientation parameter between device pattern and mask field, the system maximizes the effective exposed area in each shot. This parameter optimization reduces the total number of shots required to cover the entire wafer substrate, thereby reducing exposure time and addressing the time loss issue.
3Productivity
If the mask field utilization is low, then the exposure process is simpler, but the number of shots required increases reducing efficiency
Solution Approach 1:
The patent implements self-service by creating a system that automatically determines the optimal orientation without requiring manual intervention or complex external optimization processes. The exposure tool system itself performs the calculation and determination of the optimal relative orientation between device pattern and mask field, making the system self-optimizing. This automated approach improves productivity by reducing shot numbers while keeping the complexity contained within the system's own control mechanisms.
Data Source
AI summary
A method includes receiving a device design layout and a scribe line design layout surrounding the device design layout. The device design layout and the scribe line design layout are rotated in different directions. An optical proximity correction (OPC) process is performed on the rotated device design layout and the rotated scribe line design layout. A reticle includes the device design layout and the scribe line design layout is formed after performing the OPC process.