Scanning Exposure Wavelength Control for Wafer Magnification and Focus
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Solution Overview
Problem
Chromatic aberration in semiconductor exposure apparatuses due to wide spectrum line widths of KrF and ArF excimer laser beams leads to resolving power decrease, necessitating a method to narrow the spectrum line width and correct magnification and focus positional shifts during scanning exposure.
Innovation Solution
An electronic device manufacturing method involving scanning exposure with a pulse laser beam, where magnification and focus position are determined based on wafer height and pattern measurements, allowing for precise control of the laser beam's wavelength and focus to achieve an allowable critical dimension (CD) value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module is provided in the laser resonator to narrow the spectrum line width, then chromatic aberration is reduced and resolving power is improved, but device complexity increases
Solution Approach 1:
The patent changes the wavelength parameter of the laser beam dynamically during scanning exposure. By adjusting the wavelength to compensate for magnification changes and focus position shifts, the system achieves high resolving power without requiring additional line narrowing modules, thus avoiding increased device complexity
Solution Approach 2:
The patent replaces the mechanical/optical line narrowing module with a wavelength control system. Instead of using physical components to narrow the spectrum, the system uses wavelength adjustment to achieve the same effect of reducing chromatic aberration and improving resolving power
2Manufacturing precision
If wavelength is changed to correct magnification and focus position, then manufacturing precision is improved, but control complexity increases
Solution Approach 1:
The patent implements a feedback control system where the wavelength is adjusted based on measured magnification and focus position. The system continuously monitors these parameters and adjusts the wavelength accordingly to maintain accurate pattern formation, achieving high manufacturing precision through closed-loop control
Solution Approach 2:
The patent performs preliminary measurement of magnification and focus position before exposure. By determining these parameters in advance and pre-calculating the required wavelength adjustments, the system simplifies the control process during actual exposure while maintaining high manufacturing precision
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
Enhances resolving power by correcting magnification and focus positional shifts, ensuring accurate pattern formation on semiconductor wafers, thereby improving overlay accuracy and critical dimension control.
Implementation Method 1
generating, by the laser apparatus, the pulse laser beam that has the target wavelength for each pulse
Data Source
AI summary
An electronic device manufacturing method according to an aspect of the present disclosure includes determining magnification in a scanning width direction based on a pattern formed in a scanning field of a wafer; measuring a wafer height at points in the scanning field and determining an average value of the wafer height in the scanning width direction; determining a wavelength range of a pulse laser beam in which an allowable CD value is obtained in a case of a focus position based on the average value of the wafer height; determining a first wavelength of the pulse laser beam at which the determined magnification is obtained and determining a target wavelength based on the wavelength range and the first wavelength; outputting a pulse laser beam controlled to have the target wavelength for each pulse; and performing exposure of the scanning field of the wafer to the pulse laser beam.