Substrate Support Heater Matrix for Real-Time Plasma Uniformity Control
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Solution Overview
Problem
Substrate processing systems face challenges in achieving uniform plasma and temperature distributions, leading to non-uniformities that affect the yield and quality of semiconductor wafers, particularly due to complexities in measuring and compensating for plasma and electrostatic chuck (ESC) non-uniformities in real-time.
Innovation Solution
The system employs a controller that uses matrix and multi-zone heaters to sense temperature distributions and heat flux, allowing for in-situ and real-time compensation of plasma and ESC non-uniformities by adjusting RF power, gas chemistry, flow rate, and thermal control settings, eliminating the need for complex calibration procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional plasma uniformity measurement methods are used, then plasma uniformity can be assessed, but complex calibration procedures and additional hardware are required
Solution Approach 1:
The matrix heater elements serve dual functions: they provide thermal control to the substrate and simultaneously act as sensors to measure plasma uniformity through resistance changes. This self-service approach eliminates the need for separate measurement hardware and complex calibration procedures, as the existing heater elements are repurposed for sensing without requiring additional calibration steps
Solution Approach 2:
The matrix heater elements are designed to perform multiple functions: thermal heating of the substrate and plasma uniformity sensing through resistance measurements. This multi-functionality consolidates what would traditionally require separate components into a single integrated system, reducing overall device complexity while maintaining measurement capability
2Productivity
If real-time plasma uniformity compensation is implemented, then yield and quality improve, but system complexity increases
Solution Approach 1:
The system implements real-time feedback by continuously monitoring plasma uniformity through heater resistance measurements and automatically adjusting process parameters (RF power, gas flow rates, heater power distribution) to compensate for non-uniformities. This closed-loop feedback mechanism enables dynamic compensation that improves yield and quality without requiring overly complex external control systems
Solution Approach 2:
The compensation mechanism works by dynamically changing process parameters based on measured plasma uniformity conditions. The controller adjusts RF power levels, gas flow rates, and heater power distribution to optimal values that compensate for detected non-uniformities, enabling real-time optimization through parameter modulation rather than complex structural changes
3Device complexity
If matrix heater elements are used for both heating and sensing, then additional hardware is eliminated, but measurement accuracy may be affected by thermal effects
Solution Approach 1:
The system performs preliminary measurements of heater resistance under known conditions to establish baseline characteristics and thermal response profiles. This preliminary characterization data is stored and used to compensate for thermal effects during actual plasma uniformity measurements, allowing the system to distinguish between resistance changes due to plasma heating and those due to thermal effects alone
Solution Approach 2:
The system replaces direct temperature measurement (which would require separate thermal sensors) with electrical resistance measurement of the heater elements. Since resistance changes are directly related to temperature changes in the heater elements, this electrical measurement approach substitutes for more complex thermal sensing while providing sufficient measurement precision for plasma uniformity assessment
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 enables real-time, closed-loop compensation, improving chamber-to-chamber and wafer-to-wafer matching, reducing variability, and enhancing yield by directly measuring plasma uniformity and heat flux without additional hardware, thus improving the overall performance and cost-effectiveness of substrate processing systems.
Implementation Method 1
The matrix heater includes a plurality of heater elements arranged in a matrix and is configured to control a temperature of the semiconductor substrate during processing
Implementation Method 2
The RF generator is configured to supply RF power to the processing chamber to generate plasma in the processing chamber
Implementation Method 3
determine first resistances of the plurality of heater elements; determine second resistances of the plurality of heater elements; determine uniformity of the plasma based on the first and second resistances
Data Source
AI summary
Systems and methods of the disclosure perform in situ sensing and real time compensation of various non-uniformities in substrate processing systems. A plasma non-uniformity is sensed by determining a temperature distribution across a matrix of a plurality of micro-heaters disposed in the substrate support. Alternatively, the plasma non-uniformity is sensed by determining heat flux through the substrate support using the matrix heaters and one or more heaters used to heat one or more zones of the substrate support. The plasma non-uniformity is compensated by adjusting one or more parameters such as power supplied to the matrix heaters, RF power supplied to generate plasma, chemistry and/or flow rate of gas or gases used to generate plasma, settings of thermal control units or chillers, and so on. Additionally, non-uniformities inherent in the substrate support are sensed using the zone and matrix heaters and are compensated by adjusting the one or more parameters.