Sample Stage Lift Layout for Stable Plasma and Exhaust Flow
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Solution Overview
Problem
The existing plasma processing apparatus, as described in PTL 1, faces issues with deteriorated exhaust conductance and processing uniformity due to the expansion of the vacuum vessel volume and the sliding of radio frequency power supply cables, which changes impedance and affects plasma stability.
Innovation Solution
The plasma processing apparatus is designed with drive actuators positioned outside the vacuum vessel, connected to the sample stage via arms, which allows for vertical movement of the sample stage without expanding the vacuum vessel volume. Additionally, the radio frequency power supply cables are routed along the arms to maintain a constant spatial distance, preventing impedance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the actuator assembly is installed above the vacuum pump in a flow module and the vacuum pump and substrate support assembly are arranged coaxially, then the substrate support assembly can be moved vertically, but the volume of the vacuum vessel is expanded and exhaust conductance deteriorates
Solution Approach 1:
The actuator assembly is extracted from the vacuum vessel and installed on the outer periphery of the processing chamber. This separates the actuator from the vacuum environment, allowing it to drive the substrate support assembly vertically through a transmission mechanism (bellows and transmission mechanism) without occupying space inside the vacuum vessel, thus maintaining compact vacuum vessel volume while enabling vertical movement.
Solution Approach 2:
A transmission mechanism consisting of bellows and a transmission mechanism is introduced as an intermediary between the external actuator assembly and the substrate support assembly. This intermediary transmits the vertical driving force from the actuator through the vacuum chamber wall and internal structure to the substrate support assembly, enabling vertical movement without direct installation of the actuator inside the vacuum vessel.
2Use of energy by moving object
If the cable of the radio frequency power supply system is connected through the back surface of the substrate support assembly and moves with vertical movement, then power can be supplied to the moving assembly, but the cable slides and impedance changes causing plasma processing uniformity to deteriorate
Solution Approach 1:
The radio frequency cable connection is extracted from the moving substrate support assembly and relocated to the stationary actuator assembly. The cable is connected to the actuator assembly which remains stationary on the outer periphery of the processing chamber, eliminating cable sliding and impedance changes while still enabling power transmission to the moving substrate support assembly through the transmission mechanism.
Solution Approach 2:
The cable routing is predetermined and fixed at the stationary actuator assembly position before the substrate support assembly begins vertical movement. The cable is预先 arranged to connect to the stationary actuator rather than moving with the substrate support assembly, preventing impedance changes caused by sliding during operation.
Data Source
AI summary
Provided is a plasma processing apparatus that improves exhaust conductance in a vacuum vessel and generates stable plasma. The plasma processing apparatus has a plurality of drive actuators disposed outside the vacuum vessel, and the drive actuators and an outer peripheral portion of the bottom surface of a sample stage are connected to each other by a plurality of arms. The sample stage is driven upwards and downwards by driving the arms upwards and downwards using the drive actuators. Cables and the arms connected to the sample stage for power supply are vertically arranged in parallel, sliding of the cables is suppressed by performing a wiring route of the cables along the arms, and the volume of the vacuum vessel occupied by a sample stage unit is reduced.