Plasma Processing Optical Branching for OES Isolation
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Solution Overview
Problem
Conventional plasma processing techniques for semiconductor devices fail to accurately isolate variations in plasma light and inner wall surface states, leading to contamination and reduced yield due to variations in plasma characteristics and surface roughness, which affect nanometer-level processing accuracy and productivity.
Innovation Solution
A plasma processing apparatus with a configuration that includes a first window for plasma light emission, an external light source, an optical absorbing unit, and an optical branching unit to separate and accurately detect OES data from plasma light and inner wall surface variations, allowing for precise adjustment of processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If consecutive wafer processing is performed to improve productivity, then the number of processed wafers increases, but the inner wall surface accumulates deposits and roughness increases, causing plasma characteristic variations that reduce manufacturing precision
Solution Approach 1:
The system continuously monitors the inner wall surface state using optical detection (OES) and feeds this information back to adjust plasma processing parameters in real-time, compensating for surface degradation effects and maintaining processing precision throughout extended production runs
Solution Approach 2:
The system dynamically adjusts plasma processing parameters such as power, pressure, and gas flow rates based on detected inner wall surface conditions, adapting the process to compensate for accumulating deposits and surface roughness changes
2Reliability
If conventional OES monitoring is used to detect plasma state, then plasma characteristics can be monitored, but the detection accuracy is compromised because plasma light is affected by inner wall surface variations, reducing measurement precision
Solution Approach 1:
The system introduces an intermediary detection mechanism that separately measures the inner wall surface optical properties and uses this information to correct or compensate for surface-induced distortions in the plasma light detection, thereby recovering measurement accuracy
Solution Approach 2:
The optical detection system is segmented into separate measurement channels: one for plasma light detection and another for inner wall surface state detection, allowing independent analysis and correction of surface effects on plasma measurements
3Productivity
If the inner wall surface accumulates deposits and roughness increases, then productivity can be maintained, but shards and particles form and contaminate the wafer, reducing yield and manufacturing precision
Solution Approach 1:
The system performs preliminary detection of inner wall surface conditions using optical monitoring and takes preventive actions by adjusting processing parameters before severe contamination and particle formation occur, maintaining clean processing environments throughout extended production
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 configuration enables highly accurate detection and adjustment of plasma processing conditions, improving yield by isolating plasma light and inner wall surface variations, thereby maintaining nanometer-level processing accuracy and reducing contamination.
Implementation Method 1
an optical branching unit disposed between the light source and the first window, and having a plurality of optical ports including a first optical port for a first optical path, a second optical port for a second optical path, and a third optical port of a third optical path of light, the first optical path and the second optical path of light being branched from light emitted by the light source
Implementation Method 2
a spectroscopic (hereinafter, referred to as OES: Optical Emission Spectroscopy) monitor, which acquires a spectrum of plasma light
Implementation Method 3
an optical absorbing unit disposed outside of the processing chamber opposite to the first window in which external light emitted from the light source passing through the processing chamber is received and absorbed
Data Source
AI summary
A plasma apparatus of processing a wafer disposed in a processing chamber using plasma includes one window, another window, a light receiving unit, a light source, and an optical branching unit which is disposed between the light source and the other window, branches light emitted by the light source to an optical path toward the processing chamber and an optical path in other direction, and reflects light in the processing chamber from the other window, and a detection unit which detects the light having been emitted from the plasma and received by the light receiving unit using one branched light and other branched and reflected light. The apparatus processes the wafer according to a condition for the processing which is adjusted based on a result of the detection.