Semiconductor Substrate Position Monitoring with Multi-Pitch Gratings
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Solution Overview
Problem
Accurate measurement and control of the positioning of semiconductor substrates during manufacturing processes, particularly in photolithography, are challenging due to the need for precise detection of positional attributes such as height and alignment, which are crucial for proper exposure to irradiating light.
Innovation Solution
An apparatus and method using gratings with different pitch slits to measure positional attributes by analyzing Moire patterns through multiple slits and triangulation, enhancing detection accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple grating reticles with different pitch slits are used to enhance measurement precision, then the detection accuracy of positional attributes is improved, but the device complexity increases
Solution Approach 1:
The optical system is segmented into multiple grating reticles, each with slits of different pitches. The first grating reticle has slits with a first pitch, the second grating reticle has slits with a second pitch, and the third grating reticle has slits with a third pitch. Each grating reticle processes a different spatial frequency component of the reflected light, enabling multi-scale measurement of positional attributes including height, tilt, and curvature of the semiconductor substrate.
Solution Approach 2:
The patent extends the measurement capability from single-dimensional height detection to multi-dimensional positional attribute detection by introducing grating reticles with different slit pitches. This dimensional expansion in the optical frequency domain allows simultaneous measurement of height, tilt angle, and surface curvature, transforming a single-parameter measurement system into a multi-parameter measurement system.
2Adaptability or versatility
If multiple grating reticles with different pitch slits are used to measure multiple positional attributes, then the versatility of the monitoring apparatus is improved, but the device complexity increases
Solution Approach 1:
The monitoring apparatus is designed with universal measurement capability by incorporating three grating reticles with different slit pitches. This configuration enables a single optical system to perform multiple measurement functions: height measurement, tilt angle measurement, and curvature measurement. The first grating reticle with pitch P1, second grating reticle with pitch P2, and third grating reticle with pitch P3 collectively provide comprehensive positional attribute detection, making the system universally applicable to various semiconductor substrate inspection requirements.
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
Enables precise measurement of positional attributes like height and alignment of semiconductor substrates, improving the accuracy and efficiency of semiconductor manufacturing processes.
Implementation Method 1
a light generator configured to generate light along a first optical path towards a semiconductor substrate disposed on a substrate stage in a processing chamber, wherein upon irradiating the semiconductor substrate, the light becomes reflected light along a second optical path away from the semiconductor substrate and towards the optical detector
Implementation Method 2
a first grating reticle disposed between the light generator and the semiconductor substrate, wherein the first grating reticle includes first slits having a first pitch and second slits having a second pitch different from the first pitch
Implementation Method 3
An apparatus and method using gratings with different pitch slits to measure positional attributes by analyzing Moire patterns through multiple slits and triangulation
Data Source
AI summary
An apparatus monitoring semiconductor manufacturing equipment includes an optical detector, a light generator generating light along an optical path towards a semiconductor substrate, a first grating reticle between the light generator and the semiconductor substrate and including first slits having a first pitch and second slits having a second pitch different from the first pitch, a second grating reticle between the semiconductor substrate and the optical detector and including third slits having a third pitch different from the first pitch and the second pitch, in which the optical detector determines a positional attribute of the semiconductor substrate in relation to a first pattern and a second pattern, the first pattern corresponds to a first portion of light sequentially passing through the first slits and the third slits, and the second pattern corresponds to a second portion of light sequentially passing through the second slits and the third slits.