Optical Absorption Sensing for Vacuum Boron Clean Endpoints
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Solution Overview
Problem
Current semiconductor processing systems lack effective methods for detecting boron-containing compounds, such as boron trifluoride, under vacuum or near vacuum conditions, leading to potential under-cleaning or over-cleaning, which affects substrate contamination and process uniformity.
Innovation Solution
An optical absorption sensor is integrated downstream of the semiconductor processing chamber to measure boron-containing compounds, operating under vacuum conditions and capable of detecting extremely low levels of boron-containing compounds, ensuring accurate detection and optimizing the cleaning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional detection methods are used for boron-containing compounds, then detection is possible under atmospheric pressure, but detection under vacuum or near vacuum conditions is ineffective
Solution Approach 1:
The patent applies parameter changes by modifying the detection method to operate under vacuum conditions. The optical absorption sensor is specifically designed to detect boron-containing compounds at vacuum operating pressures, transitioning from atmospheric pressure detection to vacuum-compatible detection. This enables reliable measurement during semiconductor cleaning processes without requiring atmospheric pressure environments.
2Productivity
If cleaning process continues without precise detection, then process time is reduced, but under-cleaning or over-cleaning occurs affecting substrate contamination
Solution Approach 1:
The patent implements feedback control by using the optical absorption sensor to continuously monitor boron-containing compound levels during the cleaning process. The sensor provides real-time concentration data that feeds back to control the cleaning process termination. This enables precise endpoint detection, preventing both under-cleaning (insufficient removal) and over-cleaning (excessive processing), thereby improving manufacturing precision while maintaining productivity.
3Measurement precision
If optical absorption sensor is added to detect boron-containing compounds, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent uses an elongate optical cell as an intermediary component to enhance detection precision. The optical cell provides a controlled measurement environment with defined optical paths, allowing the sensor to detect boron-containing compounds at extremely low concentrations (1-900,000 ppm). This intermediary structure enables high measurement precision while keeping the overall system configuration manageable by separating the detection function into a dedicated component.
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 optical absorption sensor effectively detects boron-containing compounds, preventing under-cleaning or over-cleaning, reducing contamination, improving substrate processing uniformity, and enhancing process productivity by providing precise end-point detection for cleaning processes.
Implementation Method 1
The optical absorption sensor may include an infrared detector and a light source disposed at opposing first end and second end of the elongate optical cell, respectively... light entering into the elongate optical cell through the optical window may include infrared radiation having a wavenumber ranging between about 400 cm−1 and about 3,000 c−1
Data Source
AI summary
Semiconductor processing systems and methods are disclosed. An exemplary semiconductor processing system may include a semiconductor processing chamber containing a solid boron deposit, a remote plasma unit disposed upstream of the semiconductor processing chamber, and an optical absorption sensor disposed downstream of the semiconductor processing chamber. The remote plasma unit may be configured to generate plasma effluents from a fluorine-containing precursor. The optical absorption sensor may be configured to measure within an outflow from the semiconductor processing chamber a level of a boron-containing compound produced via a reaction between at least a portion of the solid boron deposit and the plasma effluents flowed from the remote plasma unit into the semiconductor processing chamber.