Voice Coil Shutter for Photolithography Exposure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photolithography machines face challenges in achieving accurate exposure dose control, particularly at low doses, due to limited shutter movement speed and the need for optical attenuators, which result in reduced yield and inefficient light-source energy utilization.
Innovation Solution
A shutter device with two hinged aluminum blades driven by a large-torque voice coil motor, featuring a permanent magnet module and guide track assembly, and controlled by a method that optimizes current output for acceleration, deceleration, and holding phases to achieve a shorter exposure duty cycle and higher energy utilization, eliminating the need for optical attenuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a mechanical shutter is used to control exposure time, then exposure dose can be controlled, but the shutter movement speed is limited and the exposure duty cycle is long
Solution Approach 1:
The patent replaces the traditional mechanical shutter system with an acousto-optic modulator (AOM) that uses acoustic waves to diffract and control light. This substitution eliminates mechanical moving parts, enabling much faster switching speeds and shorter exposure duty cycles while maintaining precise exposure dose control through acoustic signal modulation.
2Use of energy by moving object
If optical attenuators are used to reduce exposure dose, then low dose exposure is achievable, but yield is reduced and light-source energy utilization is inefficient
Solution Approach 1:
The patent replaces optical attenuators with an acousto-optic modulator that controls light intensity through acoustic wave modulation rather than physical attenuation. This enables precise control of exposure dose without wasting light energy, improving both yield and light-source energy utilization efficiency by allowing more light to reach the substrate while maintaining accurate dose control.
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
The solution enables a minimum exposure duty cycle of 28.4 ms, tripled yield at low doses, and improved light-source energy utilization per unit time, with a minimum exposure dose of 80 mJ at 2500 mW/cm², while maintaining high accuracy and efficiency.
Implementation Method 1
a magnetic damping brake motor, for driving or braking the shutter driving arm
Implementation Method 2
a magnetic damping brake motor, for driving or braking the shutter driving arm
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed herein are a shutter device, a method of controlling the shutter device, a photolithography machine and a method of controlling an exposure dose thereof. The shutter device includes a light blocking unit and a voice coil motor (100). The voice coil motor (100) includes a permanent magnet module (110), a guide track assembly (120) and a coil assembly (130). The coil assembly (130) is arranged on the guide track assembly (120), and the permanent magnet module (110) is adapted to produce a magnetic field in the guide track assembly (120). The light blocking unit includes two shutter blades (200) both connecting to the coil assembly (130). When energized, the coil assembly (130) will produce a magnetic field having a direction same as or opposite to the direction of the magnetic field in the guide track assembly (120) so that the coil assembly (130) moves forward or backward along the guide track assembly (120) to drive the two shutter blades (200) to open or close. By directly connecting the coil assembly (130) in the voice coil motor (100) to the light blocking unit, an exposure duty cycle of the shutter blades (200) can be significantly shortened, thus increasing yield under low-dose exposure conditions as well as light-source energy utilization per unit time.