Measurement System for Micro-Device Overlay Accuracy
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Solution Overview
Problem
Current micro-device manufacturing processes face challenges in achieving high overlay accuracy due to distortion from processes like resist coating, developing, etching, and CMP, which requires increasing the number of alignment marks without compromising throughput, especially in twin-stage exposure apparatuses.
Innovation Solution
A measurement system comprising multiple measurement devices and a controller that acquires position information of multiple marks on substrates before and after exposure and developing, allowing for precise alignment and exposure with an energy beam, enhancing overlay accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of alignment marks is increased to improve overlay accuracy, then measurement precision is improved, but the measurement time increases and throughput decreases
Solution Approach 1:
The wafer surface is divided into multiple measurement regions, with each region containing a subset of alignment marks. The system sequentially measures marks in different regions rather than attempting to measure all marks simultaneously, enabling comprehensive measurement of numerous marks while maintaining throughput by processing marks in segmented batches across multiple regions
Solution Approach 2:
The system transitions from measuring all marks at once to measuring marks across multiple spatial dimensions and time steps. By distributing mark measurement across different measurement regions and temporal sequences, the system achieves high overlay accuracy through comprehensive mark sampling without the throughput penalty of simultaneous measurement of all marks
2Manufacturing precision
If measurement is performed after substrate processing to capture distortion, then manufacturing precision is improved, but the total processing time increases
Solution Approach 1:
Alignment marks are formed on the wafer before the substrate undergoes distortion-inducing processing steps. This preliminary formation of marks enables subsequent measurement of distortion effects after processing, allowing the system to capture manufacturing precision data without requiring mark formation after time-consuming processing steps
Solution Approach 2:
The system dynamically schedules measurement operations at optimal points in the processing sequence. By performing mark measurement after substrate processing to capture distortion, but using pre-formed marks, the system adapts the measurement timing to the processing workflow, improving manufacturing precision measurement without proportionally increasing total processing time
Data Source
AI summary
A measurement system to be used in a micro-device manufacturing line is equipped with: a plurality of measurement devices which performs measurement processing on each substrate; and a controller that can control the plurality of measurement devices, and the plurality of measurement devices includes at least one first measurement device which acquires position information of a plurality of marks formed on a substrate.