Lift Pin Light Pipe for Substrate Temperature Measurement
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Solution Overview
Problem
In semiconductor manufacturing, measuring the temperature of a substrate during thermal processing is challenging due to overwhelming thermal energy from heat sources in the chamber, which interferes with the thermal energy emitted by the substrate.
Innovation Solution
A dual-function process chamber with an annular radiant source and lift pins equipped with light pipes that collect radiation emitted by the substrate, shielded from thermal noise, and coupled to thermal sensors via fiber optics, allowing for accurate temperature measurement by distinguishing substrate-emitted radiation from environmental noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal processing is performed in a chamber with heat sources, then thermal treatment of the substrate is achieved, but the thermal energy from heat sources overwhelms the thermal energy emitted by the substrate, making temperature measurement difficult
Solution Approach 1:
A light pipe is introduced as an intermediary component that physically connects the substrate surface to the sensor while being shielded from chamber heat sources. The light pipe collects photons emitted by the substrate and transports them to a sensor located outside the thermal environment, effectively mediating between the substrate and the measurement system while blocking thermal noise interference
Solution Approach 2:
The patent replaces conventional thermal measurement methods (which would directly measure thermal energy in the chamber) with optical detection. By detecting photons emitted by the substrate through the light pipe and converting optical signals to electrical signals, the system substitutes a mechanical/thermal measurement approach with an optical detection approach that is immune to chamber thermal noise
2Measurement precision
If a light pipe is used to collect substrate radiation, then temperature measurement capability is enabled, but the light pipe is exposed to thermal noise from chamber heat sources
Solution Approach 1:
A shield is introduced as an intermediary barrier between the light pipe and the chamber heat sources. The shield blocks thermal radiation from the chamber while allowing the light pipe to collect photons from the substrate, mediating between the measurement needs and the thermal environment
Solution Approach 2:
The sensor is extracted from the thermal chamber environment and placed outside through a vacuum feedthrough or optical port. The light pipe serves as a transmission medium that extracts the optical signal from the substrate while isolating the sensor from thermal noise, separating the measurement function from the thermal environment
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 precise temperature monitoring of substrates in noisy thermal processing environments, improving the accuracy and efficiency of thermal processing by isolating substrate thermal signals from environmental noise.
Implementation Method 1
One or more lift pins has a light pipe disposed therein to collect radiation emitted or transmitted by the substrate when the lift pin contacts the substrate surface
Implementation Method 2
The light pipe may be coupled to a thermal sensor by a conduit, such as a fiber optic
Data Source
AI summary
Disclosed are method and apparatus for treating a substrate. The apparatus is a dual-function process chamber that may perform both a material process and a thermal process on a substrate. The chamber has an annular radiant source disposed between a processing location and a transportation location of the chamber. Lift pins have length sufficient to maintain the substrate at the processing location while the substrate support is lowered below the radiant source plane to afford radiant heating of the substrate. One or more lift pins has a light pipe disposed therein to collect radiation emitted or transmitted by the substrate when the lift pin contacts the substrate surface.