Optical Temperature Measurement Subsystem for Semiconductor Processing
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Solution Overview
Problem
Existing in-situ temperature measurement systems for semiconductor processing chambers are limited by their temperature range, durability, and ability to measure fine spatial details, leading to potential damage and incomplete temperature mapping, which can result in patterning errors and contamination.
Innovation Solution
A non-contact optical temperature measurement subsystem that uses a light source to emit excitation light towards a substrate within the process chamber and a photosensitive array to detect response light, allowing for real-time temperature measurement across a wide temperature range without venting the chamber, using methods like bandgap energy or phosphor thermometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metrology devices with on-board electronics are positioned directly within the process chamber for temperature measurement, then temperature data can be obtained, but the devices are limited by temperature range and durability, leading to potential damage
Solution Approach 1:
The patent extracts the electronics (power source, processor, memory) from the process chamber environment and places them outside the chamber. Only the optical components (light source, photosensitive array) remain inside, eliminating temperature constraints on electronics while maintaining measurement capability through optical methods.
Solution Approach 2:
The patent replaces contact-based electronic temperature sensors with non-contact optical temperature measurement. The optical system uses light interaction with the substrate to determine temperature without physical contact, avoiding the temperature limitations of electronic components.
2Measurement precision
If metrology devices are brought into the process chamber for temperature measurement, then in-situ temperature data can be obtained, but the chamber must be vented and the device removed for future analysis
Solution Approach 1:
The patent enables continuous temperature measurement without interruption to the semiconductor fabrication process. The optical measurement system operates continuously while the chamber maintains vacuum, eliminating the need to vent and retrieve devices for data analysis.
Solution Approach 2:
The patent uses optical radiation as an intermediary to transfer temperature information from the substrate to detectors outside the chamber. This intermediary approach allows measurement without direct electronic contact, eliminating the need to breach chamber integrity.
3Measurement precision
If typical in-situ measurement systems are used, then temperature data can be stored in on-board memory, but the systems are limited in ability to measure fine spatial details
Solution Approach 1:
The patent segments the measurement system into optical components inside the chamber and electronics outside. The photosensitive array captures spatially-resolved optical signals from different regions of the substrate, enabling fine spatial detail measurement without complex in-chamber electronics.
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
Enables robust, real-time temperature measurement across a wide range, preventing damage and contamination, while providing detailed spatial temperature distributions, thus improving the accuracy of semiconductor fabrication processes.
Implementation Method 1
a photosensitive array to receive a response light reflected or emitted by the substrate
Implementation Method 2
An optical lens may be mounted on the chamber body between the light source and the substrate to diverge the excitation light into a wide beam spot
Implementation Method 3
The optical lens can converge the response light returning from the substrate to the photo sensitive array
Implementation Method 4
The optical temperature measurement subsystem can measure the temperature of the substrate using a bandgap energy method
Implementation Method 5
the substrate may have a core layer coated by a phosphorescent coating to luminesce response light when irradiated by excitation light
Data Source
AI summary
Embodiments include processing equipment. A processing system having an optical temperature measurement subsystem is described. In an example, the optical temperature measurement subsystem includes a light source to direct an excitation light into a process chamber, and a photosensitive array to detect a response light received from the process chamber. The detected light can be monitored to determine a temperature of a substrate mounted within the process chamber. Other embodiments are also described and claimed.