Charged Particle Beam Writing Stability
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Solution Overview
Problem
The accuracy of pattern writing in semiconductor manufacturing is compromised due to fluctuations in the electron beam trajectory caused by noise and magnetic field changes from operations like conveying and vacuum pump actuation, leading to errors in line width and exposure dose during the use of chemical amplification type resist.
Innovation Solution
A charged particle beam writing method that continues pattern writing on a target object without performing conveying operations during the writing process, unless the stop time is within the predicted pattern writing time, thereby minimizing the influence of external noise and maintaining accurate exposure dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conveying operations are performed during pattern writing, then productivity is improved through continuous operation, but manufacturing precision deteriorates due to electron beam trajectory fluctuations
Solution Approach 1:
The system performs shot amount correction in advance by calculating the correction value based on the writing speed and resist characteristics before completing the pattern writing. This preliminary correction compensates for the acid diffusion effect that occurs during the writing process, ensuring accurate line width without requiring interruption for conveying operations.
Solution Approach 2:
The system implements a feedback mechanism where the line width measurement results from test patterns are used to calculate shot amount correction values that are applied to subsequent production patterns. This closed-loop control ensures that despite continuous conveying operations, the final pattern accuracy meets specifications.
2Productivity
If conveying operations are performed during pattern writing, then productivity is improved, but measurement precision deteriorates due to magnetic field fluctuations
Solution Approach 1:
The patent separates the pattern writing function from the conveying function by performing shot amount correction based on predetermined writing speeds. This extraction allows the conveying system to operate independently without interfering with the electron beam trajectory, as the exposure parameters are pre-calculated to compensate for any potential fluctuations.
3Productivity
If pattern writing prediction time is extended to accommodate conveying operations, then productivity is improved, but manufacturing precision deteriorates due to increased acid diffusion
Solution Approach 1:
The system dynamically adjusts the shot amount (exposure dose) based on the writing speed and predicted writing time. By changing the exposure parameter in response to the writing conditions, the system compensates for acid diffusion effects that increase with longer writing times, maintaining line width accuracy even when conveying operations are performed during writing.
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 ensures consistent pattern writing accuracy by preventing external interference during the writing process, particularly when using chemical amplification type resist, by maintaining the electron beam's stability and adhering to the predicted writing time.
Implementation Method 1
a charged particle beam irradiation acid generator (generally known as a photo-acid generator) which releases and generates acid by irradiating a charged particle
Data Source
AI summary
A charged particle beam writing method includes writing a pattern on a first target object by using a charged particle beam in a writing apparatus; and conveying a second target object after having written the pattern on the first target object, wherein even though the second target object is arranged on any one of conveying paths including a carry-out port and a carry-in port of the writing apparatus, a conveying operation for the second target object is not performed during writing the pattern on the first target object.