Overlay Measurement via Two-Stage Regression Analysis
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to enhance the reliability and yield of semiconductor devices, particularly in overlay measurement processes, as devices become increasingly miniaturized and complex, requiring more accurate and reliable methods to ensure precise alignment and pattern formation across multiple layers.
Innovation Solution
A method involving the creation of overlay model functions through regression analysis to measure and compensate for overlay errors, using first-order and higher-order terms to improve alignment and pattern formation accuracy, thereby enhancing the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If overlay measurement is performed on miniaturized and highly integrated semiconductor devices, then device complexity increases, but measurement precision deteriorates
Solution Approach 1:
The overlay measurement process is segmented into two distinct stages: first-order overlay measurement using a first photoresist pattern, and second-order overlay measurement using a second photoresist pattern. This segmentation allows each measurement stage to focus on specific error components, improving overall measurement precision despite increasing device complexity
Solution Approach 2:
The invention introduces a temporal dimension to overlay measurement by performing measurements at two different stages of the manufacturing process (after first photoresist application and after second photoresist application). This multi-stage approach enables separation of different error sources that would be conflated in a single measurement, thereby maintaining precision as device complexity increases
2Ease of manufacture
If single-stage overlay measurement is used, then manufacturing process is simple, but overlay accuracy is insufficient
Solution Approach 1:
The overlay measurement process is divided into two sequential stages: first-order measurement after applying the first photoresist pattern, and second-order measurement after applying the second photoresist pattern. Each stage captures different aspects of overlay errors, enabling comprehensive error characterization and compensation that improves accuracy while maintaining manufacturing simplicity through systematic process segmentation
Solution Approach 2:
The first overlay measurement is performed as a preliminary action before the second photoresist pattern is applied. The results of this first measurement are used to generate compensation values that are applied during the second measurement stage, enabling progressive refinement of overlay accuracy without requiring complete process rework
Data Source
AI summary
A method of manufacturing a semiconductor device includes: providing a first photoresist pattern on a wafer; measuring an overlay of the first photoresist pattern; generating a first overlay model function by a first overlay regression analysis of the measured overlay; and generating a second overlay model function by a second overlay regression analysis of a difference between the measured overlay and the first overlay model function.