Electrostatic Chuck Cleaning via High-Frequency Plasma
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Solution Overview
Problem
In semiconductor processing, the electrostatically attracting mechanism in vacuum processing apparatuses faces challenges in maintaining constant temperature control and reducing particle transfer onto the wafer's rear face, leading to contamination and yield reduction due to variations in heat transfer and electrostatic attraction efficiency.
Innovation Solution
A cleaning method using a metallic cleaning electrode with high-frequency electric power applied in a vacuum processing chamber, generating plasma to remove impurities from the attracting face of the electrostatically attracting portion, ensuring consistent resistance and stable attraction force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the contact areas between the wafer and the hot plate are increased to enhance heat transfer, then the heat transfer efficiency is improved, but the number of particles transferred onto the rear face of the wafer increases
Solution Approach 1:
The hot plate surface is divided into multiple attracting electrodes arranged in an array. By segmenting the attracting face into discrete electrode regions, the system can provide distributed electrostatic attraction across the wafer surface while maintaining appropriate spacing to reduce particle transfer to any single region.
Solution Approach 2:
Different regions of the hot plate are equipped with independently controllable attracting electrodes, allowing local adjustment of electrostatic attraction strength. This enables optimization of heat transfer in areas requiring it while reducing attraction in areas prone to particle transfer, creating spatially varying local qualities.
2Force
If the attracting power is increased to enhance the electrostatic attraction, then the heat transfer is improved, but the particles transferred onto the rear face of the wafer increase
Solution Approach 1:
The attracting electrodes are designed with independently controllable power supply, allowing dynamic adjustment of electrostatic attraction strength for each electrode or group of electrodes. This enables real-time optimization of attraction force to maintain wafer contact without excessive force that would cause particle transfer.
Solution Approach 2:
The system changes the electrical parameters (voltage, current) of the attracting electrodes to optimize the balance between electrostatic attraction force and particle transfer prevention. By adjusting these parameters, the system can achieve sufficient attraction for heat transfer while avoiding the harmful effects of excessive attraction.
3Object-generated harmful factors
If the contact areas are reduced to minimize particle transfer, then the particle transfer is reduced, but the heat transfer between the wafer and the hot plate deteriorates
Solution Approach 1:
The hot plate surface is divided into multiple attracting electrodes arranged in an array. By segmenting the attracting face into discrete electrode regions, the system can provide distributed electrostatic attraction across the wafer surface while maintaining appropriate spacing to reduce particle transfer to any single region.
Solution Approach 2:
The array of attracting electrodes serves multiple functions simultaneously: providing electrostatic attraction for wafer contact, enabling localized control of attraction strength, and facilitating uniform heat distribution across the wafer surface through the distributed electrode structure.
4Object-generated harmful factors
If the attracting areas are reduced to minimize particle transfer, then the particle transfer is reduced, but the attracting force becomes insufficient
Solution Approach 1:
The hot plate surface is divided into multiple attracting electrodes arranged in an array. By segmenting the attracting face into discrete electrode regions, the system can provide distributed electrostatic attraction across the wafer surface while maintaining appropriate spacing to reduce particle transfer to any single region.
Solution Approach 2:
Different regions of the hot plate are equipped with independently controllable attracting electrodes, allowing local adjustment of electrostatic attraction strength. This enables optimization of heat transfer in areas requiring it while reducing attraction in areas prone to particle transfer, creating spatially varying local qualities.
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 method maintains a constant attracting force, reduces particle transfer, and ensures reliable temperature control during processing by uniformly cleaning the electrostatically attracting surface, enhancing processing stability and yield.
Implementation Method 1
applying a high-frequency electric power to the cleaning electrode in the state such that a cleaning gas is introduced into the vacuum processing chamber
Implementation Method 2
applying a high-frequency electric power to the cleaning electrode
Implementation Method 3
a mechanism for heating and cooling a semiconductor wafer disposed in the vacuum processing chamber
Data Source
AI summary
To provide a technique which cleans an attracting face of a mechanism for electrostatically attracting an object to be processed inside a vacuum processing apparatus and keeps its attracting force constant. The method of the present invention is for cleaning an attracting face of a hot plate which holds the object to be processed inside a vacuum processing chamber through electrostatic attraction. The invention method includes a step of cleaning the attracting face of the hot plate by applying a high-frequency electric power of 13.56 MHz to a metallic base arranged under and near the hot plate in a state in which a cleaning gas is introduced into the vacuum processing chamber.