Lithography Scanner Critical Dimension Uniformity Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniform critical dimensions on integrated circuits, as existing methods struggle to accurately separate and correct for contributions from both the photolithography mask and scanner, leading to inconsistencies in wafer-level critical dimension uniformity.
Innovation Solution
A method and system that determine the contribution to wafer-level critical dimension distribution from both the photolithography mask and scanner by measuring light transmission across the mask, applying correction factors based on transmittance variations, and adjusting scanner parameters to improve uniformity, allowing for precise correction without direct wafer measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography system adjustments are made to reduce non-uniformity, then critical dimension uniformity improves, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent segments the wafer into multiple regions and measures critical dimensions at multiple locations within each region. This segmentation approach allows the system to identify local non-uniformity patterns and apply targeted corrections to specific scanner parameters, rather than applying blanket adjustments across the entire wafer, thus improving precision while managing complexity.
Solution Approach 2:
The patent performs preliminary measurements and analyses before actual photolithography production. By measuring critical dimensions on test wafers and analyzing the data to determine scanner signature and regional variations beforehand, the system can pre-calculate correction parameters that will be applied during production, improving uniformity without adding complexity to the production process itself.
2Measurement precision
If measurements are taken at multiple locations across the wafer to improve uniformity control, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent divides the wafer into multiple regions and selects specific measurement locations within each region based on predetermined patterns. This segmented approach ensures comprehensive coverage for accurate uniformity assessment while limiting the total number of measurement points to a manageable level, balancing precision with time efficiency.
Solution Approach 2:
The patent implements a measurement strategy that takes measurements at a sufficient number of locations to achieve the required precision for detecting non-uniformity patterns, but not necessarily at every possible location. This partial action approach provides adequate measurement data for correction purposes without the time cost of exhaustive measurement of every point on the wafer.
3Manufacturing precision
If scanner parameters are adjusted to correct non-uniformity, then critical dimension uniformity improves, but the adaptability to different photo masks decreases
Solution Approach 1:
The patent performs preliminary characterization of each photo mask's transmittance properties before photolithography runs. By measuring and storing mask-specific transmittance data in advance, the system can retrieve and apply mask-appropriate correction parameters during production, ensuring both high uniformity for each specific mask and adaptability across different mask types without requiring real-time adjustments.
Solution Approach 2:
The patent adjusts scanner parameters such as illumination dosage based on the specific photo mask being used. By varying these parameters according to mask transmittance characteristics, the system maintains optimal critical dimension uniformity for each mask type while preserving adaptability across different masks, rather than using fixed scanner settings that would compromise either uniformity or versatility.
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 approach enables accurate separation of mask and scanner contributions, enabling targeted improvements to either the mask or scanner, resulting in enhanced wafer-level critical dimension uniformity and improved semiconductor chip quality.
Implementation Method 1
measuring light transmission across the mask
Data Source
AI summary
A contribution to a wafer level critical dimension distribution from a scanner of a lithography system can be determined based on measured wafer level critical dimension uniformity distribution and a contribution to the wafer level critical dimension distribution from a photo mask. Light transmission (104) across the photo mask (162) can be measured, a transmittance variation distribution of the photo mask can be determined, and the contribution to the wafer level critical dimension distribution from the photo mask (162) can be determined (132) based on the transmittance variation distribution of the photo mask.