Spectral Feature Selection Using Rotary Optics for Fast Lithography Tuning

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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

VSEngineering 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

Engineering Contradiction:

Improveadjustment speedVSAvoidactuation system complexity

Core Design Contradiction:

SpeedVSDevice complexity

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 faster adjustment speeds while maintaining controllable precision through electronic control signals, resolving the contradiction between speed improvement and system complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from linear displacement to rotational angle, using rotary stepper motors to precisely control the orientation of refractive optical elements. This parameter transformation enables rapid adjustments through angular positioning while maintaining manufacturing precision through the stepped rotation mechanism.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If conventional actuators are used, then the device is easier to manufacture, but the precision of spectral feature control is insufficient

Engineering Contradiction:

Improvespectral feature control precisionVSAvoidactuator manufacturing

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes conventional actuators with rotary stepper motors that offer precise angular positioning capability. These motors provide controlled rotational movement to adjust refractive optical elements, enabling precise spectral feature control through electronic stepping mechanisms while maintaining relatively straightforward manufacturing processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If rapid adjustments are implemented during scanning, then the productivity increases, but the system complexity increases

Engineering Contradiction:

Improvelithography process efficiencyVSAvoidcontrol system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment capabilities where refractive optical elements can be rapidly repositioned during the scanning process using rotary stepper motors. This dynamic control enables real-time spectral feature adjustments that increase lithography productivity by adapting to changing process requirements without requiring complete system redesign.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent creates a multi-functional actuation system where rotary stepper motors serve both positioning and spectral control functions. This universal approach allows a single actuation mechanism to handle multiple control tasks, increasing productivity while limiting the growth of system complexity through functional integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 the pulsed light beam

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

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

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12124053B2Spectral feature control apparatus

Publication Date: 2024.10.22 CYMER INC

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.