Charged Particle Beam Drawing Apparatus Stage Position Measurement
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Solution Overview
Problem
The accuracy of stage position measurement in charged particle beam drawing apparatuses is compromised due to vacuum vessel deformation caused by atmospheric pressure differences, leading to potential errors in pattern transfer during semiconductor manufacturing.
Innovation Solution
The apparatus incorporates a two-dimensional scale on the stage with an encoder head for precise position detection, and a support structure that maintains the encoder head's position relative to the scale even during vacuum conditions, preventing deformation-induced measurement errors by using a lid body and support body configuration that maintains pressure equality across the measurement system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser displacement measure is provided on the lateral side of the vacuum vessel to detect stage position, then stage position detection is enabled, but measurement accuracy deteriorates due to vacuum vessel deformation from atmospheric pressure differences
Solution Approach 1:
A transparent window is introduced as an intermediary component between the laser displacement measure and the stage. The window transmits laser beams while maintaining structural integrity under vacuum conditions, isolating the measurement system from pressure-induced deformations of the vacuum vessel walls.
Solution Approach 2:
The vacuum vessel is segmented into separate functional zones: a measurement zone containing the laser displacement measure and stage, and a vacuum zone containing the sample chamber. This segmentation allows the measurement components to operate in a stable pressure environment while the sample processing occurs in vacuum.
2Productivity
If the vacuum vessel is decompressed to create vacuum conditions for charged particle beam operation, then charged particle beam drawing is enabled, but the atmospheric pressure difference causes vacuum vessel deformation that compromises measurement accuracy
Solution Approach 1:
A transparent window serves as a mediator that allows laser beams to pass through while being positioned in a region less affected by vacuum-induced deformations. This enables simultaneous maintenance of vacuum conditions for charged particle beam operation and stable measurement conditions for position detection.
Solution Approach 2:
The measurement system is repositioned from the lateral side of the vacuum vessel to a location above or below the stage, utilizing a different spatial dimension. This dimensional change allows the measurement path to be established through regions of the vessel that experience minimal deformation under vacuum pressure differences.
3Device complexity
If the laser displacement measure is positioned on the lateral side of the vacuum vessel for compact design, then device compactness is improved, but the measurement accuracy deteriorates due to deformation-induced inclination of the measurement device
Solution Approach 1:
A transparent window is positioned between the laser displacement measure and the stage, serving as a stable reference surface that is less susceptible to deformation. This intermediary maintains the compact lateral positioning while providing a stable measurement interface that compensates for vessel wall deformations.
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 configuration ensures accurate stage position measurement and maintains drawing precision, while also facilitating easy maintenance of the encoder head, thus enhancing the overall reliability and efficiency of the charged particle beam drawing process.
Implementation Method 1
a laser displacement measure provided on the lateral side of the vacuum vessel
Data Source
AI summary
A charged particle beam drawing apparatus according to an embodiment includes; a vacuum vessel including a base plate; a stage provided in the vacuum vessel and supporting a sample; a stage movement mechanism provided in the vacuum vessel and moving the stage; a two-dimensional scale provided on a lower surface of the stage; a detection unit disposed under the two-dimensional scale and detecting a position of the stage by using the two-dimensional scale; and a support body supporting the detection unit.