Precision Mask Alignment With Pneumatic Deformation Feedback

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Solution Overview

Problem

Current lithography machine control systems face inefficiencies due to slow transmission speeds, increased workload on host computers, and reduced alignment efficiency, necessitating a higher precision control system for accurate, quick, and stable mask correction and alignment.

Innovation Solution

An intelligent correction device control system is developed, featuring a sixteen-way pneumatic fine-tuning mask deformation control subsystem with a PLC controller, air pressure output control, and force detection feedback, along with an alignment subsystem using an eight-way image acquisition CCD camera and industrial Ethernet communication for precise mask deformation control and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If USB serial port or Ethernet port transmission is used for image processing, then the control system can acquire images, but the transmission speed is slow and processing efficiency is reduced

Engineering Contradiction:
Improvetransmission speedVSAvoidprocessing efficiency
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The control system is segmented into a host computer control system and an independent automatic control system. The automatic control system handles real-time image acquisition and mask deformation control, while the host computer handles high-level decision making. This segmentation allows parallel processing and eliminates the bottleneck of serial communication between image acquisition and processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An automatic control system acts as an intermediary between the image acquisition devices and the host computer. This intermediary system processes images locally and controls the mask deformation in real-time, reducing the communication burden on the host computer and enabling faster response times.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If all image processing operations are completed by the host computer control system, then centralized control is achieved, but the workload of the host computer increases and processing speed decreases

Engineering Contradiction:
Improvecentralized controlVSAvoidprocessing time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The control functions are segmented between the host computer and the automatic control system. The host computer performs high-level control and monitoring, while the automatic control system handles time-critical image processing and mask adjustment operations. This division reduces the host computer's workload while maintaining centralized oversight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The automatic control system is designed to autonomously perform image processing and mask deformation control without requiring constant host computer intervention. It independently processes acquired images, determines alignment corrections, and actuates the mask positioning mechanisms, enabling self-service operation that reduces processing time.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If conventional control systems are used for mask alignment and correction, then basic functionality is provided, but alignment efficiency and precision are insufficient

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system implements closed-loop feedback control where the automatic control system continuously monitors mask position through image acquisition, compares it with the desired position, and automatically adjusts the mask deformation to correct alignment errors. This feedback mechanism enables both high precision and efficient alignment operations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces manual mechanical alignment operations with an automated control system that uses image processing and electronic control to adjust mask position. This substitution eliminates manual intervention, improves measurement precision through digital image analysis, and increases alignment efficiency through automated decision-making and actuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves high precision mask deformation control and alignment, improving efficiency and accuracy by utilizing closed-loop feedback control and high-speed image processing, thereby enhancing the overall performance of the lithography process.

Implementation Method 1

a sixteen-way cylinder and a sixteen-way electro-pneumatic proportional valve; the sixteen-way cylinder is configured to output the force deforming the mask

Methodology Applied
Scientific EffectPneumatics: Pascal's Law

Implementation Method 2

a sixteen-way force sensor configured to acquire the force value of the mask deformation

Methodology Applied
Scientific EffectForce detection: Force

Implementation Method 3

a pressure sensor configured to acquire an air pressure in a connection air pipe of the sixteen-way air cylinder

Methodology Applied
Scientific EffectPressure measurement: Pressure Increase

Implementation Method 4

compare the force value of the mask deformation with an output force set value, and generate a first control feedback quantity, so as to adjust a force deforming the mask

Methodology Applied
Scientific EffectFeedback control: Feedback

Implementation Method 5

the PLC controller subsystem is further configured to compare the air pressure with a preset air pressure value, and generate a second control feedback quantity

Methodology Applied
Scientific EffectPressure comparison control: Pressure Increase

Data Source

PatentEP4134750B1Intelligent correction device control system for super-resolution photolithography precision mask
Publication Date: 2025.06.11 INST OF OPTICS & ELECTRONICS CHINESE ACAD OF SCI
  • EP4134750B1 patent drawingFigure 1
  • EP4134750B1 patent drawingFigure 2
  • EP4134750B1 patent drawingFigure 3

AI summary

Provided is an intelligent correction device control system for a super-resolution lithography precision mask, including: a sixteen-way pneumatic fine-tuning mask deformation control subsystem configured to deform a mask, detect a force value of a mask deformation, compare the force value of the mask deformation with an output force set value, and generate a first control feedback quantity to adjust a force deforming the mask, so as to control a deformation quantity of the mask; and an alignment subsystem configured to acquire images of the mask and a substrate, and adjust a position between the mask and the substrate according to the images, so as to align the mask with the substrate. A desired precise mask deformation control may be achieved through a joint control to various subsystems by the control system. Compared with the existing implementation methods, the steps are simpler and the control system is more economically implemented. PCIe channels and independent graphics cards are used in the control system to transmit and process an alignment image signal, thereby improving an efficiency of the subsystems, so that the system may achieve a mask deformation control and alignment more quickly and more accurately.