Multi-beam Exposure Clock Period Segmentation
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Solution Overview
Problem
As the number of beams in multi-beam writing increases, it becomes difficult to define the required irradiation time using N-bit control circuits, leading to increased data transmission amounts and reduced throughput due to the need for multiple exposures with fewer bits.
Innovation Solution
The method involves setting multiple clock periods with at least one different clock period for each exposure, allowing for controlled irradiation times across multiple exposures, reducing the need for high-bit control circuits and minimizing data transmission by dividing irradiation time into common steps shared among all beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of beams in multi-beam writing increases, then writing throughput is improved, but it becomes difficult to define required irradiation time using N-bit control circuits
Solution Approach 1:
The patent segments the irradiation time control into multiple exposure steps, where each step uses a common clock period for all beams. This divides the original single high-bit control requirement into multiple lower-bit control operations, reducing the bit width needed for control circuits while maintaining precise irradiation time definition across increased beam counts
Solution Approach 2:
The patent implements a universal clock period that is commonly shared across all beams for each exposure step. This common timing mechanism allows the same control logic to be applied to all beams simultaneously, reducing the need for individual high-bit counters for each beam and enabling scalable control as beam count increases
2Measurement precision
If N-bit control circuits are used for each beam, then irradiation time can be precisely controlled, but data transmission amount increases
Solution Approach 1:
The patent segments precise irradiation time control into multiple exposure steps with common clock periods. Instead of transmitting full high-bit irradiation time data for each beam in a single operation, the system divides control into sequential steps with lower-bit requirements, reducing total data transmission while accumulating precise timing control
Solution Approach 2:
The patent changes the timing parameter from individual high-bit irradiation time values per beam to common clock period values shared across all beams for each exposure step. This parameter transformation reduces the data representation requirements while maintaining the ability to define precise irradiation times through the combination of multiple steps
3Measurement precision
If the number of bits in control circuit increases, then irradiation time can be defined more precisely, but circuit size increases
Solution Approach 1:
The patent segments high-bit irradiation time control into multiple exposure steps using lower-bit common clock period controls. This segmentation allows precise irradiation time definition to be achieved through sequential operations with smaller circuits, avoiding the need for large high-bit counters in each beam control path
Solution Approach 2:
The patent employs universal common clock period control circuits that serve all beams simultaneously. This shared control infrastructure reduces the total circuit area compared to having individual high-bit control circuits for each beam, as the same timing logic is reused across all beams for each exposure step
Data Source
AI summary
A multi charged particle beam exposing method includes setting, in multiple exposures by a plurality of shots of each beam of multi-beams where the plurality of shots continuously irradiate a same irradiation position, a plurality of clock periods including at least one different clock period where the plurality of clock periods individually control an irradiation time of each beam of the multi-beams such that a clock period of at least one exposure processing differs from clock periods of other exposure processing, and exposing respective corresponding irradiation positions on a target object with the multi-beams by controlling, in each exposure processing of the multiple exposures, the irradiation time in exposure processing concerned using a clock period which has been set in the plurality of clock periods including the at least one different clock period.