Wafer Temperature Sensor With Spiral Groove FBG Fiber
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Solution Overview
Problem
Existing methods for measuring wafer temperature in semiconductor manufacturing face challenges such as interference from electromagnetic waves, performance deterioration in low-temperature environments, and complexity and damage risks associated with multiple optical fibers for large-area temperature measurement.
Innovation Solution
A wafer temperature sensor system utilizing fiber Bragg gratings (FBG)-type optical fibers disposed in spiral grooves on bonded wafers, with a bonding adhesive of specific Young's modulus and room-temperature bonding to ensure precision and reduce damage, allowing for multiple temperature measurements with a small number of fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple optical fibers are used to measure temperature at multiple points on large-area substrates, then measurement coverage is improved, but device complexity and wafer damage risk increase
Solution Approach 1:
Multiple temperature measurement functions are merged into a single optical fiber through Fiber Bragg Grating (FBG) technology. The patent integrates multiple FBGs along the length of one optical fiber, each reflecting different wavelengths corresponding to different temperature measurement points. This allows simultaneous measurement of temperature at multiple locations on the wafer surface using a single fiber, eliminating the need for multiple separate fibers and their associated grooves.
Solution Approach 2:
The patent transitions from a spatial distribution of multiple fibers across the wafer surface to a wavelength-multiplexed approach within a single fiber. By encoding multiple measurement points along the optical path of one fiber and distinguishing them through wavelength separation, the system adds a spectral dimension to the measurement capability, effectively measuring multiple temperatures through one fiber without requiring multiple physical pathways.
2Measurement precision
If electronic components are inserted into the wafer for temperature measurement, then temperature measurement capability is improved, but reliability in low-temperature and humid environments deteriorates
Solution Approach 1:
The patent replaces electronic temperature sensing components with an optical-based measurement system. Instead of using electronic sensors, CPUs, and batteries that are susceptible to environmental damage, the system employs Fiber Bragg Gratings that utilize optical wavelength shifts to detect temperature changes. This optical approach eliminates the reliability issues associated with electronic components in low-temperature and high-humidity conditions, as optical fibers are inherently more robust in such environments.
3Measurement precision
If voltage-based temperature sensors are used during plasma processes, then temperature measurement is enabled, but measurement accuracy deteriorates due to electromagnetic wave interference
Solution Approach 1:
The patent substitutes voltage-based electrical measurement with optical measurement to eliminate interference from plasma electromagnetic waves. The Fiber Bragg Grating sensors detect temperature through changes in reflected optical wavelength, which are not affected by the high-frequency electromagnetic fields present during plasma etching and deposition processes. This optical measurement approach provides immunity to the electromagnetic interference that plagues conventional voltage-based sensors in plasma environments.
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 system effectively measures temperature at multiple points with reduced plasma interference and environmental sensitivity, maintaining consistency and precision across varying temperatures, while minimizing wafer damage and complexity.
Implementation Method 1
a fiber bragg gratings (FBG)-type optical fiber... the FBG-type optical fiber comprises a plurality of temperature measurement points in the spiral groove
Implementation Method 2
FBG optical fibers... measuring a temperature by inserting electronic components
Implementation Method 3
a bonding adhesive of specific Young's modulus... maintaining consistency and precision across varying temperatures
Implementation Method 4
the first wafer and the second wafer are bonded to each other... reduced plasma interference
Data Source
AI summary
A wafer temperature sensor includes a first wafer, a second wafer, and a fiber bragg gratings (FBG)-type optical fiber, wherein the first wafer and the second wafer are bonded to each other, wherein at least one of a bonding surface of the first wafer and a bonding surface of the second wafer comprises a spiral groove, wherein the FBG-type optical fiber is in the spiral groove, and wherein the FBG-type optical fiber comprises a plurality of temperature measurement points in the spiral groove.