Contactless Temperature Sensor Gas Cushion Workpiece
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Solution Overview
Problem
Traditional temperature sensors for semiconductor workpieces face challenges in accurately measuring temperature without contacting the workpiece, as infrared sensors struggle with emissivity variations and silicon's transparency, while contact sensors risk contamination and damage.
Innovation Solution
A contactless temperature sensor using a gas cushion to separate from the workpiece, with a thermally conductive puck and gas tube configuration that allows angular compliance and minimizes physical contact, utilizing a thermocouple for accurate temperature measurement without contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact sensor is used to measure workpiece temperature, then temperature measurement accuracy is improved, but workpiece contamination and surface damage occur
Solution Approach 1:
The patent introduces a gas cushion as an intermediary medium between the temperature sensor and the workpiece. The sensor puck is positioned close to the workpiece surface without direct contact, with gas molecules filling the gap to enable thermal conduction. This intermediary allows temperature measurement while preventing contamination and surface damage that would occur with direct contact sensors.
Solution Approach 2:
The patent employs a pneumatic principle by using a gas cushion (typically nitrogen or inert gas) to maintain separation between the sensor and workpiece. The gas is introduced into the space between the puck and workpiece surface, creating a pressurized cushion that enables thermal coupling while maintaining physical separation. This pneumatic approach prevents mechanical contact issues while preserving thermal measurement capability.
2Measurement precision
If the sensor is positioned close to the workpiece for accurate measurement, then temperature measurement accuracy is improved, but direct contact causing contamination occurs
Solution Approach 1:
The gas cushion acts as a mediator that enables thermal energy transfer from the workpiece to the sensor puck without allowing physical contact. The sensor can be positioned within micrometers of the workpiece surface for accurate measurement, while the gas layer prevents particle generation and contamination that would result from direct mechanical contact between the sensor and workpiece surfaces.
3Measurement precision
If a metallic contact sensor is used, then temperature measurement is achieved, but thermal conduction causes workpiece damage and particle generation
Solution Approach 1:
The patent replaces the traditional mechanical contact-based temperature sensing system with a contactless pneumatic thermal conduction system. Instead of relying on direct mechanical contact between metallic sensor elements and the workpiece, the system uses gas molecule collisions to transfer thermal energy. This substitution eliminates the mechanical damage and particle generation associated with hard metallic contacts while maintaining temperature measurement capability.
Solution Approach 2:
The system uses a pneumatic gas cushion to replace metallic mechanical contact for temperature sensing. The gas (typically nitrogen or inert gas at controlled pressure) serves as the thermal conduction medium, allowing heat transfer from the workpiece to the sensor puck without the workpiece damage and particle generation that occur with metallic contact sensors. The gas pressure is controlled to optimize thermal coupling while preventing contact.
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 sensor accurately measures workpiece temperature within 10°C without contacting it, preventing contamination and maintaining high accuracy, while being economical and capable of operating in various temperature ranges.
Implementation Method 1
This gas provides a cushion between the top surface of the puck and the underside of the workpiece and conducts heat from the workpiece to the puck.
Data Source
AI summary
A contactless temperature sensor for measuring the temperature of a workpiece is disclosed. The contactless temperature sensor uses a cushion of gas to separate the bottom surface of the workpiece from the top surface of the temperature sensor. The contactless temperature sensor includes a puck having a conduit therethrough. The conduit has a first portion having a first diameter, and a second portion having a second, narrower diameter. A gas tube rests in the first portion of the conduit, disposed proximate the bottom surface of the puck. Since the puck is not affixed to the gas tube, angular compliance may be achieved between the workpiece and the puck. Gas passes through the second portion and to the top surface of the puck. This gas provides a cushion between the top surface of the puck and the underside of the workpiece and conducts heat from the workpiece to the puck.