Electron Beam Lithography Device Using Individual Blankers
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Solution Overview
Problem
The existing electron beam lithography BAA system faces issues with inefficiency due to multiple beam exposure leading to unnecessary time consumption, difficulty in recognizing erroneous shots, and insufficient pattern accuracy, primarily because the beams trace in a single direction and have varying sharpness between scanning and non-scanning directions, and maintaining high beam position accuracy is challenging.
Innovation Solution
An electron beam lithography method utilizing a device with an electron gun, shielding plates, individual blankers, a whole blanker, and a deflector to control and deflect individual element beams stepwise, allowing for precise ON/OFF control based on bitmap data generated from pattern data, optimizing beam position and reducing unnecessary exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple individual element beams are used to scan continuously in one direction, then lithography coverage is improved, but drawing time increases due to unnecessary multiple exposure of identical patterns
Solution Approach 1:
The patent segments the beam scanning process into independent shot units, where each shot exposes a complete pattern at a fixed position. The shielding plate divides the electron beam into multiple individual element beams that are turned ON/OFF individually by blankers. This segmentation allows the system to expose complete patterns in discrete shots rather than continuously scanning the same pattern multiple times, thereby reducing unnecessary exposure time while maintaining full lithography coverage.
Solution Approach 2:
The patent performs preliminary positioning by deflecting the electron beam to predetermined shot positions using deflectors before exposure. The control unit determines optimal shot positions and patterns in advance, and the shielding plate and blankers are pre-configured to enable selective beam emission at these positions. This preliminary action eliminates the need for continuous scanning during exposure, allowing the system to jump directly to required positions and reduce overall drawing time.
2Area of stationary object
If identical beams trace in the scanning direction, then pattern coverage is achieved, but pattern accuracy deteriorates due to varying beam sharpness between scanning and non-scanning directions
Solution Approach 1:
The patent inverts the conventional scanning approach by fixing the beam at predetermined positions and using the shielding plate to selectively emit individual element beams only where needed. Instead of moving the beam continuously across the substrate, the system positions the beam once per shot and uses the blankers to control which beams are emitted. This inversion eliminates the directional sharpness variation problem because the beam does not trace through the substrate in a scanning motion, thereby improving pattern accuracy while maintaining full coverage.
Solution Approach 2:
The patent applies local quality control by using the shielding plate with selectively opened apertures to emit individual element beams only at specific locations required by the pattern. The blankers control the ON/OFF state of each individual beam independently, allowing precise local exposure. This local quality approach ensures that each exposed region receives the appropriate beam characteristics without being affected by scanning-induced sharpness variations, thereby improving overall pattern accuracy.
3Productivity
If continuous scanning is performed in one direction, then lithography efficiency is improved, but beam position accuracy deteriorates due to difficulty in maintaining high accuracy during scanning
Solution Approach 1:
The patent employs periodic action by dividing the lithography process into discrete shots with predetermined positions and patterns. Each shot represents a periodic cycle where the beam is deflected to a specific position, held steady for exposure, then moved to the next position. This periodic structure replaces continuous scanning, allowing the system to maintain high beam position accuracy at each shot position while achieving overall high productivity through efficient multi-beam exposure at multiple locations.
Solution Approach 2:
The patent implements feedback control by using deflectors to precisely position the electron beam at predetermined shot positions. The control unit monitors and adjusts the beam position to ensure high accuracy at each shot location. This feedback mechanism allows the system to maintain high beam position accuracy without continuous scanning, as the deflectors can quickly and accurately reposition the beam between shots based on predetermined coordinates.
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 results in a high-accuracy and high-speed electron beam lithography process by minimizing unnecessary exposure and improving pattern accuracy through precise beam control and reduced beam position errors.
Implementation Method 1
an electron gun which emits an electron beam in a Z-axis direction
Implementation Method 2
a shielding plate having a plurality of openings arranged in X and Y directions at a predetermined arrangement pitch, the shielding plate obtaining a plurality of individual element beams having a beam size which is restricted to a size of the opening from the electron beam
Implementation Method 3
a plurality of individual blankers configured to turn the plurality of individual element beams obtained by the shielding plate ON/OFF individually
Implementation Method 4
a whole blanker configured to turn the plurality of individual element beams emitted from the plurality of individual blankers ON/OFF as a whole
Implementation Method 5
a deflector which deflects the plurality of individual element beams having passed through the plurality of individual blankers and the whole blanker as a whole by every predetermined pitch, so as to scan the plurality of individual element beams stepwise with respect to the specimen
Data Source
AI summary
A high-accuracy and high-speed lithographic pattern is acquired by forming a square lattice matrix beam group with an interval which is an integral multiple of a beam size in a two-dimensional plane, switching on and off the mesh of a device to be drawn by a bitmap signal, forming a desired beam shape, deflecting the beam to a necessary position, and radiating a beam with a whole blanker being opened after the beam state is stabilized. On and off signals and a vector scan signal of each beam are provided, and the whole blanker is released after the beam is stabilized, and thus high-accuracy and high-speed lithography is performed with a small amount of data. When the total number of shots exceeds a constant value, the pattern data are modified and high-speed lithography is achieved. A semiconductor reversed bias p-n junction technique is preferably used for an individual blanker electrode.