Substrate Film Removal Using Plasma Pretreatment for Uniform Etching
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Solution Overview
Problem
Current etching processes for semiconductor substrates, such as dry etch and wet etch, face challenges including substrate damage, by-product formation, uneven etching, and excessive etchant usage, with dry etch producing harmful by-products and wet etch leading to non-uniform etching and toxic waste.
Innovation Solution
A method and apparatus that involves a two-step process: first, a plasma treatment using a treatment gas in a plasma state to surface-treat the substrate without etching, followed by a liquid treatment with a fluorine-based etchant, where different amounts of treatment gas are applied to the central and edge areas to ensure uniform etching and minimize by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etch process is used to etch the substrate with higher accuracy, then manufacturing precision is improved, but harmful by-products are generated and substrate damage occurs
Solution Approach 1:
The etching process is divided into two distinct stages: a first etching process that removes the majority of the membrane with high precision, followed by a second etching process that completes the removal while minimizing by-products. This segmentation allows each stage to be optimized for its specific function, resolving the contradiction between precision and harmful by-product generation.
Solution Approach 2:
The patent changes the parameters of the etching process by adjusting the type and flow rate of process gas, plasma power, and pressure between the first and second etching processes. By optimizing these parameters in sequence, the system achieves high etching accuracy in the first stage while minimizing harmful by-products in the second stage.
2Productivity
If wet etch process is used to achieve higher etching speed and lower cost, then productivity is improved, but toxic waste is produced and uneven etching occurs
Solution Approach 1:
The patent replaces the wet chemical etching method with a plasma-based dry etching process. This substitution eliminates the need for liquid etchants that produce toxic waste, while maintaining high etching speed through optimized plasma parameters and process gas selection.
3Ease of operation
If wet etch process is used with rotating substrate to spread etchant, then ease of operation is improved, but uniformity of etching is degraded
Solution Approach 1:
The patent applies different process conditions to different regions of the substrate by controlling plasma distribution and process gas flow patterns. This ensures that each area of the substrate receives appropriate etching conditions, achieving uniform etching across the entire surface while maintaining operational simplicity.
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 minimizes substrate damage, reduces by-product formation, optimizes etchant usage, and achieves uniform etching across the substrate, enhancing etching efficiency and reducing the time and amount of treatment liquid required.
Implementation Method 1
performing pretreatment to surface-treat the film formed on the substrate using a treatment gas in a plasma state
Implementation Method 2
allowing ion particles contained in plasma to collide with the substrate
Implementation Method 3
an electromagnetic field is formed in the inner space of the chamber, and the electromagnetic field excites the process gas provided in the chamber into a plasma state
Data Source
AI summary
A method for processing a substrate includes providing the substrate, a film being formed on the substrate, performing pretreatment to surface-treat the film formed on the substrate using a treatment gas in a plasma state, and performing, after the pretreatment, liquid treatment to remove the film from the substrate by supplying a treatment liquid onto the substrate.