Spectral Feature Selection with Stepper-Driven Refractive Optics
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Solution Overview
Problem
In semiconductor lithography, precise control of spectral features like bandwidth and wavelength of light beams is crucial for achieving accurate minimum feature sizes, but existing systems lack the necessary speed and precision for rapid adjustments during the scanning process.
Innovation Solution
The implementation of a spectral feature selection apparatus with a dispersive optical element and refractive optical elements, actuated by rapid rotary stepper motors, allows for precise rotation and adjustment of refractive optical elements to change the bandwidth and wavelength of pulsed light beams, enabling rapid and fine-tuned control of spectral features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional actuation systems are used to adjust refractive optical elements, then the system structure is simpler, but the speed and precision of spectral feature adjustments are insufficient
Solution Approach 1:
The patent replaces conventional mechanical actuation systems with rotary stepper motors that drive refractive optical elements through precise rotational steps. This substitution enables rapid positioning (improving speed) while maintaining controllable complexity through digital control signals. The stepper motor's shaft rotates parallel to the optical element's rotation axis, providing precise angular control without complex mechanical linkages.
Solution Approach 2:
The patent changes the operational parameters of the actuation system by using stepper motors that can be controlled through electrical signals rather than manual mechanical adjustment. This allows for programmable speed and precision control, enabling rapid spectral feature adjustments while the system complexity is managed through electronic control rather than mechanical complexity.
2Manufacturing precision
If manual adjustment methods are used for spectral features, then the device complexity is lower, but the precision of bandwidth and wavelength control is insufficient
Solution Approach 1:
The patent substitutes manual mechanical adjustment with electronically controlled rotary stepper motors. The motor shaft rotates parallel to the rotation axis of refractive optical elements, enabling precise angular positioning through digital step control. This provides high precision spectral feature control while managing system complexity through electronic rather than mechanical means.
Solution Approach 2:
The patent implements feedback control where the control system receives signals from detectors that measure the actual spectral features (bandwidth and wavelength) and compares them with target values. The control system then adjusts the stepper motor positions accordingly, achieving high precision control through closed-loop feedback while managing complexity through automated control algorithms.
3Productivity
If rapid adjustments of spectral features are implemented, then the productivity of lithography process improves, but the stability of optical system may be compromised
Solution Approach 1:
The patent makes the optical system dynamic by enabling rapid adjustment of spectral features through stepper motor actuation. The refractive optical elements can be rotated to different positions to change bandwidth and wavelength on demand, allowing the system to adapt quickly to different lithography requirements while maintaining stability through controlled, precise positioning rather than fixed static configuration.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and pre-positioning the refractive optical elements to the required configurations before the lithography exposure process begins. The control system receives target spectral feature parameters and pre-adjusts the optical elements accordingly, enabling rapid productivity improvement while maintaining system stability during the actual exposure process through minimal disturbances.
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 solution enables rapid and precise adjustments to the bandwidth and wavelength of light beams, allowing for more accurate control of feature sizes on semiconductor wafers, improving the efficiency and precision of the lithography process.
Implementation Method 1
a dispersive optical element arranged to interact with a pulsed light beam produced by a pulsed optical source
Implementation Method 2
three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and the pulsed optical source
Data Source
AI summary
A spectral feature selection apparatus includes a dispersive optical element arranged to interact with a pulsed light beam; three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and a pulsed optical source; and one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam. At least one of the actuation systems is a rapid actuation system that includes a rapid actuator configured to rotate its associated refractive optical element about a rotation axis. The rapid actuator includes a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element.