Charged Particle Beam Writing Position Displacement Correction
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to increased issues with position displacement due to charging phenomena in electron beam writing, where conventional methods for correcting charge-induced position displacement are inadequate, particularly in the context of double patterning techniques, and existing solutions like charge dissipation layers are costly and inefficient.
Innovation Solution
A charged particle beam writing apparatus and method that calculates and corrects position displacement by using a charge amount distribution, charge decay amount, and charge decay time constant, performing convolution with a response function to accurately adjust for position displacement caused by charge decay, thereby eliminating the need for charge dissipation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a charge dissipation layer is formed on the resist layer to prevent charging, then position displacement due to charging is reduced, but manufacturing cost increases due to additional equipment and process steps
Solution Approach 1:
The patent replaces the mechanical/chemical approach of forming a charge dissipation layer with a computational approach using a position displacement correction amount calculation unit. This unit calculates correction amounts based on charged particle beam irradiation amount distribution and charge decay characteristics, then applies these corrections to writing positions without requiring additional physical layers or equipment.
Solution Approach 2:
The patent introduces a position displacement correction amount calculation unit as an intermediary computational layer between the beam irradiation process and the final pattern writing. This unit mediates by calculating and applying position corrections based on charge decay models, eliminating the need for direct physical intervention through charge dissipation layers.
2Manufacturing precision
If conventional position displacement correction methods are used, then some charging effects are addressed, but position displacement due to charge decay is not adequately corrected, leading to insufficient pattern position accuracy
Solution Approach 1:
The patent performs preliminary calculation of position displacement correction amounts before actual pattern writing. The calculation unit pre-calculates correction values based on expected beam irradiation distribution and charge decay characteristics, then applies these pre-computed corrections to ensure accurate pattern positioning from the start.
Solution Approach 2:
The patent implements a feedback mechanism where the position displacement correction amount calculation unit continuously monitors and adjusts correction amounts based on charge decay characteristics and beam irradiation amount distribution. This feedback loop ensures that position corrections accurately compensate for charge decay effects throughout the writing process.
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 allows for precise correction of position displacement due to charge decay, improving pattern position accuracy without the need for additional equipment, thus reducing manufacturing costs and enhancing the precision of semiconductor device patterning.
Implementation Method 1
When a target workpiece, such as a mask, to which a resist film is applied, is irradiated by an electron beam, the irradiated position and its periphery may have been charged with the electron beam previously irradiated.
Implementation Method 2
The position displacement caused by this charging phenomenon has not been conventionally regarded as a problem in the variable-shaped type electron beam pattern writing apparatus.
Implementation Method 3
there exist position displacement caused by charge which does not change temporally and position displacement caused by charge which decays as time passes
Data Source
AI summary
A charged particle beam writing apparatus includes a charge amount distribution calculation unit configured to calculate a charge amount distribution which is charged by irradiation of a charged particle beam onto a writing region of a target workpiece, by using a charge decay amount and a charge decay time constant both of which depend on a pattern area density, a position displacement amount distribution calculation unit configured to calculate a position displacement amount of each writing position due to charge amounts of the charge amount distribution by performing convolution of each charge amount of the charge amount distribution with a response function, and a writing unit configured to write a pattern on the each writing position where the position displacement amount has been corrected, using a charged particle beam.