In-situ Pyrometer Calibration for CVD Reactors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pyrometer calibration methods in semiconductor wafer processing are disruptive to production and result in temperature measurement variations across multiple reactors, leading to uncertainty and the need for individual reactor tuning, due to factors like calibration spread, instability, and drift in black body furnaces, as well as variable pyrometer installation and drift over time.
Innovation Solution
An in-situ pyrometer calibration method and system that allows for simultaneous temperature measurement and calibration without removing the operating pyrometer from the reactor, using a calibrating pyrometer to adjust calibration parameters and store look-up tables, enabling temperature matching across multiple reactors during wafer treatment processes like chemical vapor deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional black body furnace calibration is used, then pyrometer calibration can be performed, but production is disrupted and temperature measurement variations occur across multiple reactors
Solution Approach 1:
The calibration process is performed in advance during reactor maintenance periods or between production runs, using a standardized black body furnace procedure. This preliminary calibration establishes baseline temperature measurements for multiple reactors before production begins, eliminating the need for disruptive calibration during operational periods.
Solution Approach 2:
A standardized calibration protocol is created as a reference model using the black body furnace, and this calibration methodology is copied and applied uniformly across all reactors. Look-up tables generated from the calibration process are replicated and stored for use by multiple reactors, ensuring consistent temperature measurements without requiring each reactor to undergo separate calibration disruptions.
2Measurement precision
If black body furnace calibration is used, then pyrometer calibration can be achieved, but calibration spread, instability, and drift occur leading to temperature measurement variations
Solution Approach 1:
During production operation, pyrometers continuously measure wafer carrier temperatures and this data is fed back to the control system. The measured temperatures are compared against expected values and calibration look-up tables, and calibration parameters are automatically adjusted to maintain consistent temperature measurements across all reactors, compensating for drift and instability in real-time.
Solution Approach 2:
The calibration approach transitions from fixed black body furnace calibration to dynamic calibration parameter adjustment. Instead of relying on the instability of black body furnace temperature standards, the system modifies pyrometer calibration parameters based on actual production temperature measurements and look-up tables, adapting to changing conditions and maintaining measurement consistency.
3Reliability
If individual reactor tuning is performed to compensate for calibration variations, then temperature measurement consistency can be improved, but device complexity and calibration time increase
Solution Approach 1:
A universal calibration system is implemented where a single black body furnace calibration protocol serves all reactors. The calibration-generated look-up tables are stored centrally and applied across multiple reactors, eliminating the need for each reactor to have its own separate calibration system. This multi-functional approach maintains temperature control repeatability while reducing overall system complexity and calibration time.
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 reduces production disruptions, enhances temperature control repeatability, and allows for universal temperature control recipes across multiple reactors by compensating for calibration errors and installation variations, thereby improving the consistency of semiconductor device properties.
Implementation Method 1
non-contact pyrometers that are adapted to measure the temperature of the wafer carrier and/or the wafers during processing
Data Source
AI summary
A method of in-situ pyrometer calibration for a wafer treatment reactor such as a chemical vapor deposition reactor desirably includes the steps of positioning a calibrating pyrometer at a first calibrating position and heating the reactor until the reactor reaches a pyrometer calibration temperature. The method desirably further includes rotating the support element about the rotational axis, and while the support element is rotating about the rotational axis, obtaining first operating temperature measurements from a first operating pyrometer installed at a first operating position, and obtaining first calibrating temperature measurements from the calibration pyrometer. Both the calibrating pyrometer and the first operating pyrometer desirably are adapted to receive radiation from a first portion of a wafer support element at a first radial distance from a rotational axis of the wafer support element.