Electrostatic Chucking for Plasma Processing Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processing methods for semiconductor wafers face issues with surface abrasion and contamination due to thermal expansion, leading to inefficient heat transfer and degradation in temperature control, which affects the productivity and quality of the plasma processing.
Innovation Solution
A plasma processing apparatus with a dielectric film on the sample stage, where a part of the sample is initially heated and then electro-statically chucked, reducing abrasion and damage by controlling the electrostatic chucking area and using helium gas for improved heat transfer, allowing for precise temperature control and reduced contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the sample is electro-statically chucked to the sample stage for heating, then the heat transfer efficiency is improved, but the surface abrasion and contamination increase due to thermal expansion
Solution Approach 1:
The electrostatic chucking is divided into two distinct phases: a first electrostatic chucking phase during heating where the sample is held at a first potential, and a second electrostatic chucking phase during processing where the sample is held at a second potential. This segmentation allows optimization of each phase independently - stronger chucking force during heating to maintain contact and heat transfer, and reduced chucking force during processing to minimize abrasion and contamination.
2Reliability
If the electrostatic chucking force is increased to improve heat transfer, then the temperature control is improved, but the surface abrasion and damage increase
Solution Approach 1:
The electrostatic chucking force is made dynamic rather than static. The control unit adjusts the electrostatic potential between the sample and sample stage based on the processing phase. During the heating phase, a higher potential difference is applied to increase chucking force and improve heat transfer reliability. During the plasma processing phase, the potential difference is reduced to minimize chucking force and protect surface integrity. This dynamic adjustment resolves the contradiction between reliable temperature control and surface protection.
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 enhances the efficiency of heat transfer and reduces surface abrasion, leading to improved temperature control and increased productivity in plasma processing by minimizing the generation of fine particles and maintaining the surface integrity of the sample stage.
Implementation Method 1
heat transfer gas such as helium is injected into the gap spaces between the lower surface of the sample and the upper surface of the sample stage
Implementation Method 2
heat transfer gas such as helium is injected into the gap spaces between the lower surface of the sample and the upper surface of the sample stage
Implementation Method 3
the sample is electro-statically chucked to the upper surface of the sample stage
Data Source
AI summary
In a plasma processing apparatus including a processing room disposed in a vacuum vessel, a sample stage located in the processing room, a dielectric film disposed on the top surface of the sample stage and serving as the sample mounting surface of the sample stage, and a plurality of electrodes embedded in the dielectric film for chucking the sample to the dielectric film when supplied with electric power, a part of the sample is chucked by supplying electric power to at least one of the electrodes while the sample is mounted on the sample stage; the sample is heated up to a predetermined temperature; a larger part of the sample is chucked by supplying electric power to the other of the electrodes; and the processing of the sample using the plasma is initiated.