Low-Temperature Wafer Chuck Assembly for Uniform Plasma Processing
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Solution Overview
Problem
The challenge in plasma processing is achieving spatially uniform processing of larger semiconductor wafers with smaller feature sizes, requiring precise temperature control and resistance to corrosive plasma environments, while existing technologies struggle with thermal uniformity and material compatibility.
Innovation Solution
A wafer chuck assembly with an electrically insulating puck, a conductive shaft, and a base, incorporating heat exchange channels and RF/DC voltage capabilities to stabilize temperature and clamp the workpiece, along with a conductive plate and diffuser system to generate and direct plasma uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conductive chuck is used to provide RF power for plasma generation, then plasma processing capability is improved, but thermal control becomes difficult and temperature uniformity deteriorates
Solution Approach 1:
The chuck is divided into multiple independent heating zones with separate RF coils, allowing each zone to be controlled independently for uniform temperature distribution across the wafer surface
Solution Approach 2:
The system uses independent RF power control for each heating zone, adjusting power parameters to achieve uniform thermal distribution while maintaining plasma generation capability
2Use of energy by moving object
If a conductive chuck is used for RF power delivery, then plasma ignition is improved, but thermal damage to the workpiece increases
Solution Approach 1:
The system dynamically adjusts RF power delivery in real-time based on temperature feedback from multiple sensors, preventing thermal accumulation and damage while maintaining plasma generation
Solution Approach 2:
Multiple temperature sensors provide feedback to the control system, which adjusts RF power delivery to maintain optimal temperature and prevent thermal damage to the workpiece
3Productivity
If larger wafers are processed to increase productivity, then output is improved, but achieving spatially uniform processing becomes more difficult
Solution Approach 1:
The chuck surface is divided into multiple heating zones that can be independently controlled, ensuring uniform temperature and processing conditions across larger wafer areas
Solution Approach 2:
The segmented heating system provides universal temperature control capability across different wafer sizes, maintaining processing uniformity whether processing small or large wafers
4Reliability
If traditional conductive materials are used for the chuck, then electrical conductivity is improved, but resistance to corrosive plasma environments deteriorates
Solution Approach 1:
The chuck uses composite construction with corrosion-resistant materials (such as ceramic or coated metal) combined with embedded RF coils, providing both plasma environment resistance and electrical conductivity for RF power delivery
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 solution ensures precise temperature control across the wafer, maintaining uniformity within a degree or less, and prevents thermal and corrosive damage, enabling effective plasma processing without material degradation.
Implementation Method 1
stabilizing temperature of a chuck by a heat exchange fluid through an inner puck element of the chuck
Implementation Method 2
providing a DC voltage differential across two spatially separated electrodes within the electrically insulating top surface, to clamp the workpiece to the chuck
Implementation Method 3
providing an RF voltage between a conductive plate beneath the chuck, and one or more walls of the chamber, to ignite a plasma from the process gases
Data Source
AI summary
A wafer chuck assembly includes a puck, a shaft and a base. The puck includes an electrically insulating material that defines a top surface of the puck; a plurality of electrodes are embedded within the electrically insulating material. The puck also includes an inner puck element that forms one or more channels for a heat exchange fluid, the inner puck element being in thermal communication with the electrically insulating material, and an electrically conductive plate disposed proximate to the inner puck element. The shaft includes an electrically conductive shaft housing that is electrically coupled with the plate, and a plurality of connectors, including electrical connectors for the electrodes. The base includes an electrically conductive base housing that is electrically coupled with the shaft housing, and an electrically insulating terminal block disposed within the base housing, the plurality of connectors passing through the terminal block.