Charged-Particle Beam Drawing Apparatus Pressure Control
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Solution Overview
Problem
The challenge in maintaining consistent pressure within a charged-particle-beam drawing apparatus, such as an electron-beam drawing apparatus, is exacerbated by fluctuations in cleaning gas supply, leading to defocusing of the electron optical system and deterioration of drawing accuracy due to beam drift caused by contamination and pressure variations.
Innovation Solution
A drawing apparatus with a cleaning gas generator, a compensation gas introduction system, and a valve controller that adjusts the supply of cleaning gas and compensation gas (like inert gases or oxygen) to maintain a predetermined pressure, using first and second valves to ensure stable operation even when the cleaning gas supply is interrupted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cleaning gas is supplied to suppress contamination, then drawing accuracy is improved, but pressure fluctuations cause defocusing of the electron optical system
Solution Approach 1:
A pressure control valve is introduced as an intermediary component between the cleaning gas supply and the drawing chamber. This valve mediates the gas flow to maintain stable pressure while still allowing cleaning gas to reach the drawing part, thus preventing both pressure fluctuations and contamination accumulation.
Solution Approach 2:
A pressure gauge provides real-time feedback on the pressure within the drawing part to the valve controller. The controller adjusts the pressure control valve based on this feedback to maintain pressure within a predetermined range, ensuring stable electron optical system operation while enabling continuous cleaning gas supply.
2Reliability
If cleaning gas supply is increased to eliminate contamination, then beam drift is reduced, but pressure control becomes difficult
Solution Approach 1:
The pressure control valve serves as a mediator that decouples the cleaning gas supply rate from the actual pressure in the drawing chamber. It allows high cleaning gas flow rates to suppress contamination and stabilize the beam, while simultaneously regulating the pressure to remain within acceptable limits for easy operation.
Solution Approach 2:
The system dynamically adjusts the valve opening degree parameter based on pressure gauge readings to maintain pressure within a predetermined range. This parameter adjustment enables the system to handle variable cleaning gas supply conditions while maintaining stable pressure and beam operation.
3Object-affected harmful factors
If cleaning gas generator stops due to abnormality, then safety is improved, but pressure reduction causes defocusing
Solution Approach 1:
The pressure control valve is pre-configured to respond automatically to pressure changes. When the cleaning gas generator stops and pressure begins to drop, the valve adjusts in advance to maintain pressure stability, preventing defocusing before it occurs and ensuring continuous drawing accuracy even during generator abnormalities.
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 solution effectively maintains the pressure within a predetermined range, reducing defocusing and improving drawing accuracy by controlling the gas supply dynamically, making it easier to manage beam stability and accuracy without complex electron beam control mechanisms.
Implementation Method 1
cleaning gas is introduced into an electron-beam drawing apparatus and ozone or radicals is caused to react with contamination and change the contamination to volatile gas
Implementation Method 2
ozone or radicals is caused to react with contamination and change the contamination to volatile gas
Implementation Method 3
An irradiated electron beam (or diffused electrons thereof) reacts with the gas described above and contamination is formed on the surfaces of components of an electron optical system
Implementation Method 4
If charges are accumulated on the contamination, an electric field is generated due to a difference in the quantity of accumulated charges and the irradiated electron beam is deflected by the electric field
Implementation Method 5
the irradiated electron beam is deflected by the electric field. As a result, the irradiation position of the electron beam fluctuates
Data Source
AI summary
A drawing apparatus includes: a drawing part; a cleaning-gas generator; a first valve between the cleaning-gas generator and the drawing part and adjusting a supply amount of gas to the drawing part; a first pressure gauge measuring a pressure in the drawing part; a compensation-gas introducing part introducing compensation-gas to be supplied between the cleaning-gas generator and the first valve; a second valve between the compensation-gas introducing part and the first valve and adjusting a supply amount of the compensation-gas; and a valve controller controlling the first and second valves, wherein the valve controller controls the first valve to supply the cleaning-gas at a predetermined flow rate to the drawing part and controls the second valve to cause a pressure in the drawing part to be a predetermined pressure when the first pressure gauge detects a pressure reduction due to a reduction in a supply flow rate of the cleaning-gas.