Exposure Tolerance Estimation for Semiconductor Devices
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Solution Overview
Problem
In photolithography, there is a challenge in estimating exposure tolerance reliably due to variations in pattern dimensions caused by differences in exposure conditions, even when using the same mask pattern, which affects the robustness and accuracy of semiconductor device manufacturing.
Innovation Solution
An exposure tolerance estimation method is developed that involves setting multiple regions on a substrate, forming patterns using an exposure mask with varying exposure conditions, measuring pattern dimensions, selecting a region with an intermediate exposure level, and calculating the exposure tolerance based on the relationship between exposure conditions and dimensions to suppress in-plane variations and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exposure is performed using the same mask pattern under different exposure conditions, then pattern dimensions vary, but this variation reduces exposure tolerance estimation reliability
Solution Approach 1:
The substrate surface is divided into multiple regions, and exposure is performed on each region under different exposure conditions. By segmenting the measurement across multiple regions rather than relying on a single region, the patent reduces the impact of local variations and improves the reliability of exposure tolerance estimation while maintaining pattern dimension accuracy.
2Reliability
If multiple regions are measured to improve reliability, then measurement time increases, but this reduces productivity
Solution Approach 1:
The patent performs exposure on multiple regions simultaneously in advance, and then selects representative regions for detailed measurement. This preliminary action of creating multiple exposed regions allows for more reliable estimation without requiring exhaustive measurement of all regions, thus maintaining productivity while improving reliability.
3Reliability
If exposure conditions are varied to assess tolerance, then process complexity increases, but this worsens device complexity
Solution Approach 1:
The patent systematically varies exposure parameters (such as exposure amount, focus position, or illumination conditions) across different regions to assess exposure tolerance. By using controlled parameter changes rather than complex process modifications, the patent achieves robust tolerance assessment while minimizing increases in overall device and process complexity.
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 method improves the reliability of exposure tolerance estimation and pattern dimension accuracy, reducing the influence of substrate variations and ensuring higher precision in semiconductor device manufacturing by selecting suitable regions and averaging exposure relationships.
Implementation Method 1
In photolithography used in manufacturing a semiconductor device etc., a difference occurs in the dimensions of a pattern on completion due to a difference in exposure conditions
Data Source
AI summary
According to one embodiment, an exposure tolerance estimation method is disclosed. The method can include setting a plurality of regions along a first surface of a substrate. The method can form a plurality of patterns for estimation by performing exposure on each of the regions using at least three levels of exposure condition using an exposure mask. The method can measure dimensions of the patterns for estimation and find relationships between the exposure condition and the dimensions. The method can select a first region from the regions. In the first region, a first dimension of a first pattern for estimation formed by exposure using a first exposure condition of an intermediate level out of the at least three levels falls within a previously set range. In addition, the method can calculate an exposure tolerance from a relationship between the first exposure condition and the first dimension.