Metrology System for Substrate Stress and Deformation Measurement
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Solution Overview
Problem
Conventional lithography processes struggle to effectively measure and correct localized deformations in semiconductor substrates, which can lead to device yield issues and performance variations due to film stress and topography variations between layers, especially as critical dimensions shrink.
Innovation Solution
A metrology system that uses a laser source to emit a light beam, split into sub-beams by a beam displacing device and polarizer, to create an interference pattern on a recording device, allowing for the detection and analysis of substrate surface slope and curvature, enabling precise measurement and correction of localized deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithography processes are used with substrate clamping, then global curvature effects are minimized, but localized curvature variations cannot be effectively reduced
Solution Approach 1:
The patent divides the measurement system into multiple derivative modules (e.g., X-derivative module and Y-derivative module) that independently measure curvature in different directions. This segmentation allows targeted correction of localized curvature variations in specific regions and orientations, overcoming the limitation of conventional global clamping methods.
Solution Approach 2:
The patent implements local quality control by using multiple derivative modules to measure and correct curvature at different locations and orientations across the substrate. Each module provides localized measurement data that enables region-specific correction, rather than applying uniform global constraints.
2Measurement precision
If multiple derivative modules are added to measure localized curvature, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent designs derivative modules that can be configured to measure curvature in different directions (X, Y, and diagonal orientations) using the same basic module architecture. This multi-functionality allows a single module design to serve multiple measurement purposes, reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent measures curvature derivatives in multiple dimensional orientations (X-direction, Y-direction, and diagonal directions) to comprehensively characterize localized curvature variations. By adding directional dimensions to the measurement capability, the system achieves complete curvature mapping without requiring exponentially more complex apparatus.
3Productivity
If critical dimensions are reduced for next-generation devices, then device density increases, but sensitivity to film stress and topography variations increases
Solution Approach 1:
The patent performs curvature measurement and analysis using multiple derivative modules before lithographic processing. This preliminary measurement allows identification and correction of localized curvature variations and film stress issues before they affect the lithography process, ensuring that subsequent high-precision patterning is performed on a uniformly flat substrate surface.
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 system provides accurate measurement of substrate deformation, enabling effective correction and improving device yield by reducing localized curvature and stress variations, essential for reliable production of next-generation semiconductor devices with smaller feature sizes.
Implementation Method 1
a first polarizer that is positioned between the first displacing device and the first recording device, wherein the first polarizer is configured to cause the two or more sub-light beams provided from the first displacing device to form an interference pattern on the detection surface of the first recording device
Implementation Method 2
a first beam displacing device adapted to cause a portion of the light beam received from the beam splitter to be split into two or more sub-light beams that are displaced a distance apart from each other
Implementation Method 3
a first polarizer that is positioned between the first displacing device and the first recording device, wherein the first polarizer is configured to cause the two or more sub-light beams provided from the first displacing device to form an interference pattern
Data Source
AI summary
Embodiments of the disclosure provide a metrology system. In one example, a metrology system includes a laser source adapted to transmit a light beam, a lens adapted to receive at least a portion of the light beam from the laser source, a first beam splitter positioned to receive at least the portion of the light beam passing through the lens, a first beam displacing device adapted to cause a portion of the light beam received from the beam splitter to be split into two or more sub-light beams a first recording device having a detection surface, and a first polarizer that is positioned between the first displacing device and the first recording device, wherein the first polarizer is configured to cause the two or more sub-light beams provided from the first displacing device to form an interference pattern on the detection surface of the first recording device.