Electrostatic Chuck Thermal Uniformity Control
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Solution Overview
Problem
Existing electrostatic chucks in semiconductor manufacturing exhibit thermal non-uniformity due to manufacturing variations, which can lead to significant spatial temperature variations across the wafer, affecting the precision of etching processes and the formation of structures on silicon chips.
Innovation Solution
A thermal performance measurement system is developed, comprising a chamber, a base to support the wafer chuck, a heater, and an infrared imaging system to measure the temperature of the chuck, allowing for precise control and calibration of the thermal performance by adjusting coolant flow and heater zones to achieve uniform temperature profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling is used to remove plasma power heat from the chuck, then thermal uniformity is improved, but manufacturing variations cause spatial temperature variations across the wafer
Solution Approach 1:
The patent applies local quality by dividing the chuck into multiple independently controlled heater zones that can be adjusted to compensate for local thermal non-uniformities caused by manufacturing variations. Each zone can be independently controlled to achieve uniform temperature distribution across the wafer surface despite variations in cooling plate thermal resistance.
Solution Approach 2:
The patent implements feedback control by measuring the actual temperature distribution across the chuck surface and using this information to adjust the heater zones accordingly. This closed-loop control system compensates for manufacturing variations in the cooling plate and achieves the desired thermal uniformity.
2Adaptability or versatility
If independently controlled heaters in multiple zones are used, then process window is widened, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the heater system into multiple independent zones that can be controlled separately. This allows different regions of the chuck to be heated to different temperatures, enabling compensation for thermal non-uniformities and providing flexibility for various plasma processing conditions.
Solution Approach 2:
Each heater zone is independently controlled to provide local temperature adjustment, allowing the system to adapt to different process requirements and compensate for local thermal variations without requiring complex global control mechanisms.
3Manufacturing precision
If thermal performance measurement and control is implemented, then etch rate uniformity is improved, but measurement and control complexity increases
Solution Approach 1:
The patent implements feedback control by measuring the actual temperature distribution across the chuck surface and using this information to adjust the heater zones accordingly. This closed-loop control system compensates for manufacturing variations in the cooling plate and achieves the desired thermal uniformity.
Solution Approach 2:
The patent replaces complex mechanical temperature control mechanisms with an optical measurement system (infrared camera) that non-contactly measures temperature distribution. This substitution simplifies the control system while achieving precise thermal uniformity through electronic control of heater zones.
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 system significantly improves thermal uniformity across the wafer chuck, enabling more precise temperature control and uniform etch rates, allowing for the formation of smaller structures on silicon chips by compensating for manufacturing defects and variations in thermal resistance.
Implementation Method 1
an infrared imaging system to measure the temperature of the chuck while the chuck is heated
Implementation Method 2
a heater to heat the chuck
Data Source
AI summary
An apparatus and method are described for measuring the thermal performance of a wafer chuck, such as an electrostatic chuck. In one example, the apparatus ha a chamber, a base to support a wafer chuck in the chamber, a heater to heat the chuck, a window through the exterior of the chamber, and an infrared imaging system to measure the temperature of the chuck while the chuck is heated.