Etching End Point Detection Using Reference Light Compensation
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Solution Overview
Problem
The complexity of semiconductor device structures has increased fabrication time due to complicated semiconductor manufacturing processes, particularly in etching processes, where detecting the etching end point is challenging and affects process reliability.
Innovation Solution
A substrate processing method and apparatus that introduces a reference light and plasma light into a process chamber, allowing for the detection of the etching end point by analyzing the absorption and emission signals, with compensation adjustments based on the change rates of these signals to improve detectability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If plasma etching process is performed to etch the etching target layer, then the etching process can be completed, but it is difficult to accurately detect the etching end point due to interference from plasma light emission
Solution Approach 1:
A polarizing filter is introduced as an intermediary component between the light source and the etching target layer. The filter selectively transmits light with a specific polarization state while blocking plasma light emission, thereby mediating the interaction between the reference light and the etching process to enable accurate end point detection without plasma interference
Solution Approach 2:
The patent changes the polarization state parameter of the reference light by using a polarizing filter. This parameter change allows the reference light to maintain a distinguishable characteristic that can be used for accurate detection even in the presence of plasma light emission, resolving the detection accuracy problem
2Manufacturing precision
If complicated semiconductor manufacturing processes are used to fabricate highly integrated semiconductor devices, then device integration is improved, but fabrication time is increased
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the light transmitted through the etching target layer during the etching process. When the etching is complete and light transmission reaches a predetermined threshold, the system automatically terminates the etching process, providing real-time feedback that prevents over-etching and enables precise control without requiring extended process times
Solution Approach 2:
The patent performs preliminary action by establishing a predetermined light transmission threshold before the etching process begins. This pre-set criterion allows for rapid and accurate determination of the etching end point, eliminating the need for complex real-time analysis and reducing overall fabrication time while maintaining high precision
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 enhances the reliability and efficiency of etching processes by accurately determining the etching end point, reducing fabrication time and improving the consistency of semiconductor device production.
Implementation Method 1
introducing a reference light into the process chamber; receiving the reference light and the plasma light; detecting an etching end point by analyzing the plasma light and the reference light
Implementation Method 2
using a radio frequency (RF) power supply to provide a RF power to generate a plasma light in the process chamber
Implementation Method 3
a polarizing filter adjacent to the light-receiving part and filtering at least a portion having a transverse electric wave (TE) mode of a light received on the second viewport
Data Source
AI summary
A substrate processing method includes providing a substrate into a process chamber; introducing a reference light into the process chamber; generating a plasma light in the process chamber while performing an etching process on the substrate; receiving the reference light and the plasma light; and detecting an etching end point by analyzing the plasma light and the reference light. Detecting the etching end point includes a compensation adjustment based on a change rate of an absorption signal of the reference light with respect to a change rate of an emission signal of the plasma light.