Charged Particle Beam Dose Correction for Resist Heating
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Solution Overview
Problem
Conventional charged particle beam writing methods fail to accurately correct for the heating effect caused by backscattered electrons, leading to significant correction errors in line width accuracy during semiconductor manufacturing, due to the lack of consideration for temperature influences from peripheral shots.
Innovation Solution
A method involving the writing of evaluation and peripheral patterns with varying settling times to isolate the heating effect, calculating a correlation parameter that defines the relationship between width dimension changes, temperature increases, and backscatter doses, allowing for precise dose correction of the charged particle beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of electron beam shots and dose are increased to reduce shot noise and pattern edge roughness, then line width accuracy is improved, but resist heating occurs resulting in degradation of line width accuracy
Solution Approach 1:
The patent applies preliminary action by calculating and applying heating correction in advance before the actual writing process. The correction values are pre-computed based on the writing pattern and conditions, allowing the system to compensate for resist heating effects before they occur during high-dose writing, thus maintaining line width accuracy without suffering from temperature degradation
Solution Approach 2:
The patent implements feedback by using measured line width data from test patterns to determine correction values for heating effects. This feedback loop allows the system to adjust and optimize the heating correction parameters based on actual writing results, ensuring that line width accuracy is maintained even when high doses are used to reduce shot noise
2Productivity
If conventional proximity effect correction is applied without considering temperature influences, then writing speed is maintained, but significant correction errors occur in line width accuracy
Solution Approach 1:
The patent merges proximity effect correction with heating correction into a unified correction framework. By combining these two correction mechanisms, the system maintains the efficiency of proximity effect correction while adding temperature compensation, thus achieving both high writing speed and accurate line width control without significant correction errors
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 effectively separates the dimensional changes caused by the heating effect from other factors, enabling accurate dose correction and improved line width accuracy in semiconductor manufacturing.
Implementation Method 1
the substrate overheats resulting in a phenomenon called 'resist heating' of changing the resist sensitivity
Implementation Method 2
calculating a temperature increase amount of a figure pattern which is increased due to heat transferred from another shot
Data Source
AI summary
A parameter acquiring method for dose correction of a charged particle beam includes writing evaluation patterns on a substrate coated with resist; writing, while varying writing condition, a peripheral pattern on a periphery of any different one of the evaluation patterns, after an ignorable time as to influence of resist temperature increase due to writing of an evaluation pattern concerned has passed; and calculating a parameter for defining correlation among a width dimension change amount of the evaluation pattern concerned, a temperature increase amount of the evaluation pattern concerned, and a backscatter dose reaching the evaluation pattern concerned, by using, under each writing condition, a width dimension of the evaluation pattern concerned, the temperature increase amount of the evaluation pattern concerned at each shot time, and the backscatter dose reaching the evaluation pattern concerned from each shot.