In-Plane Distortion Prediction via Out-of-Plane Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in predicting and mitigating in-plane distortions of substrates, which can lead to errors in lithographic patterning and other downstream applications due to elastic deformations caused by processing steps and thickness variations.
Innovation Solution
A system and method that measures out-of-plane distortions of substrates in an unchucked state using a substrate geometry measurement tool, applies a two-dimensional plate model to determine effective surface film stress, and calculates in-plane distortions in a chucked state, allowing for adjustments to process or metrology tools to minimize distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If process steps and thickness variations are applied to a wafer, then semiconductor devices are fabricated, but elastic deformations cause in-plane and out-of-plane distortions leading to overlay errors
Solution Approach 1:
The system performs preliminary measurement of out-of-plane distortions on the wafer before it enters the lithography process. By measuring the wafer shape in an unchucked state using a substrate geometry measurement tool, the system can predict the in-plane distortions that will occur during processing and pre-compensate for them, thereby preventing overlay errors before they occur
Solution Approach 2:
The system implements a feedback mechanism where measured out-of-plane distortion data is fed into a prediction model that estimates in-plane distortions. This feedback loop allows the system to continuously monitor and adjust for wafer deformations, enabling real-time correction of overlay parameters to maintain manufacturing precision
2Manufacturing precision
If out-of-plane distortions are measured in an unchucked state, then in-plane distortions can be predicted, but additional measurement and calculation steps are required
Solution Approach 1:
The system introduces a two-dimensional plate model as an intermediary between the measured out-of-plane distortions and the predicted in-plane distortions. This mathematical model acts as a mediator that translates the measured wafer shape data into predictions of in-plane deformations, simplifying the complex relationship between different types of distortions while maintaining prediction accuracy
Solution Approach 2:
The system replaces direct mechanical measurement of in-plane distortions (which would require complex in-situ measurement equipment during lithography) with a computational approach. By using a prediction model based on out-of-plane measurements and plate theory, the system substitutes a simpler measurement system with a computational prediction system that achieves the same goal of characterizing in-plane distortions
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 prediction and reduction of in-plane distortions, thereby improving the precision of semiconductor fabrication by providing real-time feedback and feedforward adjustments to maintain uniformity and flatness, reducing overlay errors.
Implementation Method 1
the various process steps applied to a wafer required during device fabrication as well as thickness variations may result in elastic deformation of the wafer
Implementation Method 2
A substrate geometry measurement tool is disclosed configured to measure out-of-plane distortions of the substrate in an unchucked state
Data Source
AI summary
The determination of in-plane distortions of a substrate includes measuring one or more out-of-plane distortions of the substrate in an unchucked state, determining an effective film stress of a film on the substrate in the unchucked state based on the measured out-of-plane distortions of the substrate in the unchucked state, determining in-plane distortions of the substrate in a chucked state based on the effective film stress of the film on the substrate in the unchucked state and adjusting at least one of a process tool or an overlay tool based on at least one of the measured out-of-plane distortions or the determined in-plane distortions.