Multi-beam Writing Apparatus Defective Beam Compensation
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Solution Overview
Problem
In multi-beam writing techniques for semiconductor manufacturing, the presence of continuous ON beams (defective beams) leads to uncontrollable irradiation errors and increased complexity in dose control, particularly due to the difficulty in managing continuous ON beams during standby times and the need for extensive blanking mechanisms.
Innovation Solution
A method is introduced where the irradiation region is divided into small regions, and an offset dose is calculated to account for defective beams, allowing for precise control of irradiation time using a common blanking mechanism, even with defective beams always ON, by switching beams during each pass and adjusting irradiation times accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple exposure is performed to handle continuous ON beams, then defective beams can be managed, but irradiation time error increases and dose control precision deteriorates
Solution Approach 1:
The patent introduces a standby dose calculation that performs preliminary compensation for continuous ON beams. By calculating the standby dose in advance based on the number of beams and exposure times, the system compensates for defective beams before actual irradiation occurs, eliminating irradiation time errors without requiring multiple exposure attempts.
Solution Approach 2:
The patent changes the dosimetry parameter by introducing a standby dose component that is added to the normal beam dose. This parameter change allows the system to account for continuous ON beams mathematically rather than through repeated physical exposures, maintaining dose precision while handling defective beams.
2Reliability
If two-stage blanking devices are arranged to block continuous ON beams, then defective beams can be controlled, but device structure becomes complicated and large
Solution Approach 1:
The patent replaces the mechanical two-stage blanking device with a computational dosimetry system. Instead of using additional physical blanking mechanisms, the system uses a standby dose calculation that mathematically compensates for continuous ON beams, thereby controlling defective beams without increasing device complexity or size.
3Manufacturing precision
If individual blanking mechanisms are arranged for each beam, then dose control can be performed, but apparatus structure becomes complex when number of beams increases
Solution Approach 1:
The patent introduces a universal standby dose calculation that applies to all beams simultaneously. This single computational mechanism replaces the need for individual blanking control mechanisms for each beam, maintaining individual dose control precision while significantly reducing apparatus complexity as the number of beams increases.
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 enables accurate control of irradiation time and dose distribution, reducing errors and simplifying the apparatus structure by using a single common blanking mechanism, thereby enhancing the precision and efficiency of multi-beam writing.
Implementation Method 1
a multi charged particle beam writing method includes: calculating an offset dose to irradiate all of a plurality of small regions
Data Source
AI summary
A multi charged particle beam writing method includes calculating an offset dose to irradiate all the small regions by multiplying one beam dose equivalent to a maximum irradiation time of multi-beams of each pass in multiple writing by a maximum number of defective beams being always ON to irradiate one of the small regions; calculating an incident dose, in addition to the offset dose, for each of the small regions; and performing multiple writing, using multi-beams including a defective beam being always ON, such that a beam of a total dose, between the incident dose and the offset dose, irradiates a corresponding small region for each small region, while switching a beam for each pass of the multiple writing, and controlling an irradiation time equivalent to the offset dose by a common blanking mechanism collectively blanking-controlling the multi-beams.