Micromirror Actuator Control Using Shared Signal Amplifier
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Solution Overview
Problem
The existing methods for driving micromirrors in microlithographic projection exposure apparatuses require multiple actuators and signal amplifiers, leading to increased complexity and hardware outlay, which complicates the precise control of tilt angles and illumination angle distribution in illumination systems.
Innovation Solution
A method and device that utilize three actuators to tilt a micromirror about two axes, where one actuator's control signal is set to a constant value, reducing the number of signal amplifiers needed by determining control signals such that one actuator receives a constant signal, allowing for simpler actuator driving and reduced hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple actuators and signal amplifiers are used to control micromirror tilt angles, then the precision of mirror alignment is improved, but the device complexity and hardware outlay increase
Solution Approach 1:
The patent combines the functions of multiple signal amplifiers into a single shared signal amplifier that serves all three actuators. The control signals for tilting the micromirror about two axes are generated by this single amplifier, eliminating the need for multiple separate amplifiers and reducing hardware complexity while maintaining precise control capability
Solution Approach 2:
The single signal amplifier is designed to universally control all three actuators through a multiplexer system. The amplifier can dynamically switch between different actuators based on which one requires adjustment at any given moment, making it a multi-functional device that replaces what would traditionally require multiple dedicated amplifiers
2Adaptability or versatility
If three actuators are used to tilt micromirror about two axes, then the adaptability of illumination settings is improved, but the number of signal amplifiers increases
Solution Approach 1:
The patent merges the signal amplification functions into a single shared amplifier that serves all three actuators. By using a multiplexer to route control signals from this single amplifier to the appropriate actuator, the system maintains the adaptability provided by three actuators while reducing the quantity of amplifiers from three to one
Solution Approach 2:
The multiplexer acts as an intermediary device that connects the single signal amplifier to all three actuators. It dynamically routes the control signal to the appropriate actuator based on which one needs adjustment, enabling a single amplifier to effectively control multiple actuators without requiring direct connections to each
3Adaptability or versatility
If more signal amplifiers are used, then the control range of micromirror tilt angles is improved, but the switching speed between illumination settings decreases
Solution Approach 1:
The system dynamically assigns control of different actuators to the single signal amplifier based on real-time requirements. The multiplexer rapidly switches between actuators as needed, allowing the system to maintain full control range while achieving faster switching between illumination settings by eliminating the inertia and coordination delays associated with multiple independent amplifiers
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 reduces the number of signal amplifiers required, simplifies the control and regulation of micromirror tilt angles, and enables faster switching between illumination settings, enhancing the precision and efficiency of illumination angle distribution adjustments.
Implementation Method 1
When a voltage is applied between a control electrode and the mating electrode, an attractive force action is created between them owing to electrostatic attraction
Data Source
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AI summary
A micromirror (24) of a micromirror array (22) in an illumination system (10) of a microlithographic projection exposure apparatus can be tilted through a respective tilt angle (αx, αy) about two tilt axes (x, y). The micromirror (24) is assigned three actuators (E1, E2, E3) which can respectively be driven by control signals (U1, U2, U3) in order to tilt the micromirror (24) about the two tilt axes (x, y). Two control variables (SGx, SGy) are specified, each of which is assigned to one tilt axis (x, y) and which are both assigned to unperturbed tilt angles (αx, αy). For any desired combinations of the two control variables (SGx, SGy), as a function of the two control variables (SGx, SGy), one (E1) of the three actuators is selected and its control signal (U1) is set to a constant value, in particular zero. The control signals (U1, U2, U3) are determined so that, when the control signals (U1, U2, U3) are applied to the other two actuators (E2, E3), the micromirror (24) adopts the unperturbed tilt angles (αx, αy) as a function of the two control variables (SGx, SGy).