Alignment Measurement Mark Structure for Semiconductor Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor processes face inefficiencies in alignment and measurement, where alignment patterns are limited to alignment only and do not serve additional purposes, and separate measurement steps can contaminate wafers with gas byproducts during photolithography, especially when measuring patterns on thick photoresist layers.
Innovation Solution
A structure for an alignment measurement mark comprising a first overlay mark and a second overlay mark, where the first overlay mark's projection is located on the periphery or inner side of the second overlay mark, allowing simultaneous alignment and measurement without generating gas byproducts, using an optical measurement method to improve efficiency and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate measurement process is performed using SEM in a vacuum cavity, then measurement precision is improved, but gas byproducts are generated that contaminate the wafer
Solution Approach 1:
The patent combines the alignment mark and measurement mark into a single integrated structure. The alignment mark serves dual purposes: it enables optical alignment between layers and simultaneously serves as the measurement target for critical dimension measurement. This merging eliminates the need for separate measurement processes that generate gas byproducts, while maintaining measurement precision through the integrated design.
Solution Approach 2:
The alignment mark is designed to perform multiple functions: it provides alignment references for photolithography processes and simultaneously serves as the measurement target for critical dimension analysis. This multi-functionality eliminates the need for separate measurement marks and processes, preventing wafer contamination while maintaining measurement capabilities.
2Manufacturing precision
If separate alignment and measurement processes are performed, then each process can be optimized independently, but productivity is reduced due to multiple process steps
Solution Approach 1:
The patent merges alignment and measurement functions into a single process step. The optical alignment system uses the same mark structure that will be used for measurement, allowing both alignment and measurement to be performed during the same photolithography process without requiring separate measurement steps, thereby improving productivity while maintaining precision.
Solution Approach 2:
The measurement mark is pre-integrated into the alignment mark structure during photolithography pattern formation. This preliminary integration ensures that the measurement target is already in place when alignment is performed, eliminating the need for subsequent measurement process steps and improving overall process efficiency.
Data Source
AI summary
The application provides a structure for an alignment measurement mark and a method for an alignment measurement, and includes a first overlay mark and a second overlay mark. The second overlay mark includes a pattern structure to be measured. A layer where the first overlay mark is located is adjacent to a layer where the second overlay mark is located. An orthographic projection of the first overlay mark onto the layer where the second overlay mark is located is located at an inner side of the second overlay mark, or an orthographic projection of the first overlay mark onto the layer where the second overlay mark is located is located at a periphery of the second overlay mark.