Charged Particle Beam Lithography Block Division Strategy
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Solution Overview
Problem
Conventional charged particle beam lithography methods face inefficiencies in pattern area density calculation and proximity effect correction due to variations in calculation time across blocks of different sizes, leading to suboptimal processing times.
Innovation Solution
A charged particle beam lithography apparatus and method that divides the pattern forming area into non-uniform first block areas for equal shot distribution and uniform second block areas for proximity effect correction, using area density and dose calculations to optimize beam dosing for efficient pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the chip area is divided into calculation areas (blocks) of the same size to perform proximity effect correction calculation for each block, then the correction calculation can be performed systematically, but the calculation time varies significantly for each block because the number of shots varies from block to block
Solution Approach 1:
The patent divides the chip area into multiple calculation areas (blocks) for systematic proximity effect correction calculation. Each block is further divided into small mesh areas to enable efficient computation of pattern area density and correction coefficients, resolving the contradiction between systematic correction and calculation time variation.
2Loss of time
If the block size is changed to make the number of shots contained in each block substantially equal, then the calculation time for pattern area density can be made substantially equal, but the proximity effect correction calculation becomes inefficient due to variations in calculation time for each block
Solution Approach 1:
The patent dynamically adjusts block sizes to balance two requirements: making the number of shots per block substantially equal for efficient pattern area density calculation, while maintaining block sizes that optimize proximity effect correction calculation efficiency. This dynamic sizing resolves the contradiction between calculation time equality and correction efficiency.
3Manufacturing precision
If conventional proximity effect correction calculation is performed with equal-sized blocks, then the correction can be applied uniformly, but the overall processing time increases due to inefficient shot distribution across blocks
Solution Approach 1:
The patent changes the parameter of block size from uniform to non-uniform, where block sizes are adjusted based on the number of shots they contain. This parameter change enables both efficient proximity effect correction calculation and optimized processing speed by balancing shot distribution across blocks.
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 efficient pattern area density and proximity effect correction calculations by balancing shot distribution and block size, reducing variations in calculation time and enabling high-speed processing of large datasets.
Implementation Method 1
an electron beam 330 that has passed through the opening 411 after being irradiated from a charged particle source 430
Implementation Method 2
The electron beam 330 that passed through the opening 411 after being irradiated from a charged particle source 430 is deflected by a deflector
Data Source
AI summary
A charged particle beam lithography apparatus includes a first block area divider configured to divide a pattern forming area into a plurality of first block areas in order to make a number of shots when forming a pattern substantially equal; an area density calculator configured to calculate, using a plurality of small areas obtained by virtually dividing the pattern forming area into mesh areas of a predetermined size smaller than all of the first block areas, a pattern area density of each small area positioned therein for each of the first block areas; a second block area divider configured to re-divide the pattern forming area divided into the plurality of first block areas into a plurality of second block areas of a uniform size, which is larger than the small area; a corrected dose calculator configured to calculate, using the pattern area density of each small area, a proximity effect-corrected dose in each corresponding small area positioned inside the second block area for each of the second block areas; a beam dose calculator configured to calculate, using the proximity effect-corrected dose of each small area, a beam dose of a charged particle beam in each corresponding small area; and a pattern generator configured to form a predetermined pattern on a target object by irradiating a charged particle beam of the beam dose calculated for each of the small areas.