Electrostatic Chuck Temperature Sensing With Shared ADC Switching
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Solution Overview
Problem
As the number of zones in a plasma processing apparatus increases to finely control substrate temperature, the number of temperature sensors and components required for temperature measurement also increases, leading to a difficulty in managing the increased complexity and components.
Innovation Solution
The plasma processing apparatus incorporates a configuration where multiple temperature sensors are connected in parallel to a common signal line and ground line, with switches controlling the connection to a single analog-to-digital converter, reducing the number of required components and enabling efficient temperature measurement in a time division manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of zones is increased to finely control substrate temperature, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
Multiple temperature sensors are connected in parallel to a single analog-to-digital converter, merging multiple measurement channels into one conversion unit. This reduces the number of ADC components needed while maintaining the capability to measure temperatures across multiple zones for precise control
Solution Approach 2:
Switches control the connection of temperature sensors to the ADC in a time-division manner, periodically connecting different sensors to the same converter. This allows sequential measurement of multiple zones using a single ADC, reducing overall device complexity while preserving fine temperature control capability
2Measurement precision
If the number of temperature sensors is increased to measure multiple zones, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple temperature sensors are merged into a single measurement system by connecting them in parallel to one analog-to-digital converter. This consolidation reduces the number of ADC components while maintaining the ability to precisely measure temperatures in multiple zones through time-division multiplexing
Solution Approach 2:
A single analog-to-digital converter is designed to serve multiple temperature sensors through time-division switching. This universal ADC handles measurements from all zones sequentially, eliminating the need for dedicated ADCs for each sensor and reducing overall system complexity while maintaining measurement precision
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber, a base disposed in the plasma processing chamber, an electrostatic chuck disposed on the base, a first heater electrode layer disposed in the electrostatic chuck, a second heater electrode layer disposed in the electrostatic chuck at a position different from the first heater electrode layer in a plan view, a first temperature sensor configured to measure a temperature of the first heater electrode layer, a second temperature sensor configured to measure a temperature of the second heater electrode layer, a signal line electrically connected to the first temperature sensor and the second temperature sensor, a ground (GND) line electrically connected to the first temperature sensor and the second temperature sensor, and a signal detector electrically connected to the signal line and the GND line.