Multi-Beam Sub-Array Correction for Accurate Pattern Writing
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Solution Overview
Problem
In multi-beam writing processes for semiconductor devices, the displacement of beam positions due to lens distortion complicates precise pattern formation, leading to increased maximum doses and reduced throughput due to the need for dose modulation between adjacent pixels.
Innovation Solution
A method that divides the multi-beam array into sub-arrays to calculate and correct for positional deviations, allowing for pattern shifting and dose adjustment in each sub-array to maintain accurate beam positioning and reduce irradiation time, thereby improving writing accuracy and throughput without increasing pixel doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dose modulation between adjacent pixels is used to correct beam position displacement, then writing accuracy is improved, but the maximum dose for pixels is increased and the multi-beam irradiation cycle is lengthened, degrading writing throughput
Solution Approach 1:
The patent divides the multi-beam array into multiple sub-arrays, where each sub-array is independently controlled with its own deflection units. This segmentation allows position correction to be applied locally to each sub-array without requiring global dose modulation, thereby maintaining writing accuracy while avoiding the throughput degradation caused by increased maximum doses and longer irradiation cycles.
2Manufacturing precision
If a large number of multi-beams with individual deflection units are provided to correct position displacement individually, then writing accuracy is improved, but device complexity increases
Solution Approach 1:
Instead of providing individual deflection units for each beam, the patent segments the beam array into sub-arrays and provides deflection units at the sub-array level. This reduces the number of deflection units required while still enabling position correction for each beam within its sub-array, thereby balancing writing accuracy with device complexity.
Solution Approach 2:
The patent merges the control of multiple beams into sub-array level control. By combining beams into sub-arrays and controlling them collectively with shared deflection units, the system reduces the total number of control elements while maintaining the ability to correct position displacements for individual beams through coordinated control of the sub-array.
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 enhances writing accuracy by correcting beam position displacements through pattern shifting and dose adjustments, maintaining high throughput while preventing throughput degradation and minimizing dose increases.
Implementation Method 1
The blanking aperture array has electrode pairs for individually deflecting the beams, and an opening for beam passage is formed between each electrode pair. Blanking control on a passing electron beam is performed by controlling the electrode pair (blanker) at the same potential or at different potentials.
Implementation Method 2
an electron beam discharged from an electron gun passes through a shaping aperture array having multiple openings, and forms a multi-beam (multiple electron beams)
Data Source
AI summary
In one embodiment, a multi-beam writing method is for irradiating each of pixels defined on a substrate, placed on a stage, with each beam of a multi-beam to form a pattern. The method includes obtaining a position correction amount of the pattern by each of a plurality of sub-arrays into which an array of the multi-beam is divided at least in a predetermined direction, based on the positional deviation amount of each beam of each of the sub-arrays, which obtained by dividing an array of the multi-beam at least in the predetermined direction, calculating an dose of the each beam irradiated to each pixel for shifting the position of the pattern drawn for each of the sub-arrays based on the position correction, and performing multi-writing using at least a portion of each two or more of the sub-arrays with the calculated dose.