Wafer Temperature Verification via Deposition Thickness in Etch Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Maintaining consistent wafer temperatures during semiconductor processing is challenging, as temperature variations can significantly affect etch feature dimensions, and existing methods using thermocouple wafers are expensive and prone to contamination.
Innovation Solution
A method involving the deposition of a layer on a blank wafer within an etch chamber, measuring its thickness to calculate surface temperature accuracy, and compensating the etch chamber accordingly, allowing for precise temperature calibration without the need for expensive thermocouple wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouple wafers are used for temperature measurement, then temperature accuracy can be verified, but the cost increases and contamination risk increases
Solution Approach 1:
The patent replaces expensive thermocouple wafers with inexpensive silicon wafers that are deposited upon once and then discarded. The deposition chamber uses standard silicon wafers as substrates, which are much cheaper than thermocouple-equipped wafers. After a single deposition process, these wafers are discarded rather than reused, eliminating contamination risks while maintaining cost-effectiveness.
Solution Approach 2:
The patent introduces a deposition process as an intermediary method to indirectly measure wafer temperature. Instead of directly measuring temperature with thermocouples, the system deposits a known thickness of material on the wafer and uses the deposition rate (which is temperature-dependent) to calculate the actual wafer temperature. This intermediary deposition step provides temperature verification without requiring thermocouple wafers.
2Measurement precision
If thermocouple wafers are used for temperature measurement, then temperature accuracy can be verified, but the cost increases
Solution Approach 1:
The patent replaces expensive thermocouple wafers with inexpensive silicon wafers that are deposited upon once and then discarded. The deposition chamber uses standard silicon wafers as substrates, which are much cheaper than thermocouple-equipped wafers. After a single deposition process, these wafers are discarded rather than reused, eliminating contamination risks while maintaining cost-effectiveness.
Solution Approach 2:
The patent creates a simplified copy of the temperature measurement function. Instead of using complex thermocouple wafers, it uses a simple deposition process on standard wafers to create a measurable record (deposited layer thickness) that correlates to temperature. This copying approach achieves temperature verification through a much simpler, cheaper mechanism.
3Device complexity
If deposition rate is used to determine temperature, then temperature calibration becomes simpler and more consistent, but requires establishing correlation between deposition rate and temperature
Solution Approach 1:
The patent performs preliminary calibration by depositing known thicknesses of material at known temperatures to establish the correlation between deposition rate and temperature. This calibration data is stored and used for future temperature measurements. By doing this preliminary work, the actual temperature verification process becomes simple and consistent, requiring only measurement of deposited thickness and reference to the calibration curve.
Solution Approach 2:
The patent implements a feedback mechanism where the measured deposition thickness is compared against the calibrated deposition rate vs. temperature relationship. This feedback allows the system to determine actual wafer temperature during processing and provide corrective action if temperature deviations are detected, making the calibration process both simple and self-correcting.
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
This approach provides reliable, consistent, and stable temperature calibration, reducing errors and costs by using a simpler process with blank wafers, and demonstrates a systematic correlation between deposition rate and temperature, enabling precise temperature control across multiple etching chambers.
Implementation Method 1
A layer is deposited over the wafer... providing a deposition gas, forming the deposition gas into a deposition plasma
Implementation Method 2
a systematic correlation between deposition rate and temperature
Data Source
AI summary
A blank wafer is placed in an etch chamber. A layer is deposited over the blank wafer, comprising providing a deposition gas, forming the deposition gas into a deposition plasma, and stopping the deposition gas. The blank wafer with the deposited layer is removed from the etch chamber. The thickness of the deposited layer is measured. Wafer temperature accuracy is calculated from the measured thickness of the deposited layer. The etch chamber is compensated according to the calculated wafer temperature accuracy. A wafer with an etch layer over the wafer and a patterned mask over the etch layer is placed into the etch chamber. The etch layer is etched in the etch chamber.