Electrostatic Chuck Electrode Segmentation for Wafer Dechucking
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Solution Overview
Problem
In next-generation CMC processes, the increased wafer temperature leads to enhanced residual adsorption forces, causing wafer cracking during dechucking due to the Johnson-Rahbek Effect, resulting in prolonged dechucking times and reduced productivity.
Innovation Solution
A plasma process apparatus with a junction portion formed between the focus ring and electrostatic chuck using a ductile material for improved heat transfer efficiency, low adhesiveness, and excellent heat resistance, along with independently controlled electrodes to prevent wafer damage during dechucking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer temperature is increased to improve selection ratio in CMC process, then the process effectiveness is improved, but the residual adsorption force increases causing wafer cracking during dechucking
Solution Approach 1:
The electrostatic chuck is divided into multiple independently controllable electrode regions. During dechucking, different electrode regions are deactivated in sequence to gradually reduce the holding force, preventing sudden release that causes wafer cracking while maintaining the high temperature process conditions needed for selection ratio.
Solution Approach 2:
The electrostatic chuck transitions from a static holding state to a dynamic dechucking state by sequentially controlling multiple electrode regions. This dynamic approach allows the holding force to be gradually reduced and redistributed, preventing wafer damage during the transition from process to dechucking mode.
2Object-affected harmful factors
If dechucking staffs are added and adjusted to reduce residual adsorption force, then wafer cracking is prevented, but the dechucking time increases to about 350 seconds
Solution Approach 1:
Instead of using multiple separate dechucking staffs that sequentially handle the wafer, the electrostatic chuck itself is segmented into multiple electrode regions that can be independently controlled. This allows the dechucking function to be integrated into the existing chuck structure, eliminating the need for additional staff operations and reducing dechucking time while still preventing wafer cracking through controlled force distribution.
Solution Approach 2:
The electrostatic chuck performs the dechucking function itself by sequentially deactivating its own electrode regions, eliminating the need for external dechucking staff. The chuck automatically manages the release of the wafer through programmed electrode control, significantly reducing the dechucking time from 350 seconds to a much shorter duration.
3Device complexity
If a single electrode structure is used in the electrostatic chuck, then the structure is simple, but the wafer cannot be dechucked uniformly causing damage
Solution Approach 1:
The electrostatic chuck employs multiple electrode regions arranged in a segmented pattern rather than a single continuous electrode. Each electrode region can be independently controlled, allowing uniform dechucking across the wafer surface by sequentially activating or deactivating different regions, thus maintaining wafer integrity during the release process.
4Device complexity
If the focus ring is directly attached to the electrostatic chuck, then the joining structure is simple, but the heat transfer efficiency is insufficient at high temperatures
Solution Approach 1:
A junction portion with composite structure is provided between the focus ring and the electrostatic chuck. This junction portion includes a first portion and a second portion with different material properties, where the second portion has higher thermal conductivity than the first portion. This composite structure improves heat transfer efficiency from the electrostatic chuck to the focus ring while maintaining a relatively simple overall joining structure.
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
The solution reduces dechucking time, enhances process efficiency, and maintains joining reliability at high temperatures, preventing wafer damage and improving productivity.
Implementation Method 1
an electrostatic chuck which supports a wafer inside the chamber
Implementation Method 2
a plurality of cooling gas supply lines which penetrates the electrostatic chuck in a third direction perpendicular to the first and second directions and is configured to provide a cooling gas to the wafer
Implementation Method 3
a junction portion disposed between the first portion of the electrostatic chuck and the focus ring
Data Source
AI summary
A plasma process apparatus includes a chamber in which a plasma process is performed, an electrostatic chuck which supports a wafer inside the chamber and comprises a first portion and a second portion disposed on the first portion, a first electrode disposed inside the electrostatic chuck, a second electrode which is spaced apart from the first electrode inside the electrostatic chuck, surrounds the first electrode in a plane defined by the first direction and a second direction perpendicular to the first direction, and is disposed on the same plane as the first electrode, a power supply configured to apply a voltage to each of the first electrode and the second electrode, a plurality of cooling gas supply lines which penetrates the electrostatic chuck in a third direction perpendicular to the first and second directions and is configured to provide a cooling gas to the wafer.