Plasma Etching Endpoint Detection and Recipe Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The stability and reproducibility of etching processing in plasma processing apparatuses are compromised due to variations in processing conditions and inaccurate end-point judgment, especially when processing multiple wafers, leading to inconsistent machining dimensions and configurations.
Innovation Solution
A plasma processing apparatus and method that adjust processing conditions based on the elapsed time until termination of subsequent etching steps, using light-emission detection to judge the end-point of etching processing and modify recipes for subsequent wafers, ensuring stable and reproducible etching performance by accounting for chamber environment changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant set recipe is used for etching processing of multiple wafers, then processing efficiency is maintained, but machining result variation increases due to outer disturbances
Solution Approach 1:
The patent implements feedback control by detecting the actual etching end-point timing and using this information to adjust processing conditions for subsequent wafers. The system monitors light emission intensity during etching, compares it with reference values to determine end-point timing, and feeds this information back to modify the recipe for the next wafer, thereby compensating for variations caused by outer disturbances and maintaining consistent machining results across multiple wafers.
2Measurement precision
If end-point judgment is made using light-emission detection, then etching termination timing can be determined, but machining accuracy is insufficient when processing films with difficult end-point judgment
Solution Approach 1:
The patent addresses the limitation of light-emission detection for difficult-to-judge films by changing the detection parameter from light emission intensity to etching time duration. By measuring how long it takes to reach the end-point (time from start to end-point detection), the system can accurately determine processing completion even for films where light emission characteristics are not distinct, thereby improving machining accuracy for such materials.
3Productivity
If multiple wafers are processed continuously, then productivity increases, but chamber environment variations cause deviation in after-processing dimension and configuration
Solution Approach 1:
The patent applies preliminary action by adjusting the processing recipe for the next wafer in advance, based on end-point timing data from the previous wafer. Before processing the next wafer, the system calculates the necessary recipe modifications (such as etching time or power adjustments) and pre-configures the optimized parameters, ensuring that even as chamber environment changes during continuous processing, each subsequent wafer receives appropriately adjusted conditions to maintain dimensional accuracy.
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 stability and reproducibility of etching processing by reducing variations in machining dimensions and improving the accuracy of the entire film structure, even when processing multiple wafers with varying chamber conditions.
Implementation Method 1
plasma discharge is generated under a reduced-pressure condition. Moreover, radicals or ions, which are generated within this plasma, are caused to react with the wafer surface
Implementation Method 2
the judgment on the end point of the etching processing is made by detecting a phenomenon which is specific to the development of the etching processing from the light-emission within the plasma generated inside the processing chamber
Data Source
AI summary
A plasma processing apparatus for applying an etching processing to a wafer by using at least two steps of the etching processing which operate with plasma formed within a pressure-reduced processing chamber, the wafer being located within the processing chamber inside a vacuum vessel, and having a mask on a silicon-composed substrate and a film structure, the film structure including processing-target films located under the mask, wherein the plasma processing apparatus is equipped with a function for processing another different wafer in such a manner that a processing condition at a precedent-stage step of the two steps of the etching processing in the processing of the different wafer is adjusted based on a result obtained by detecting a time which has elapsed until termination of a subsequent-stage step of the two steps of the etching processing.