Plasma Etching of Variable-Aperture Recesses With Selective Deposition
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Solution Overview
Problem
Existing etching methods struggle to achieve uniform etching rates in regions with different aperture dimensions on semiconductor substrates, leading to inconsistencies in trench formation.
Innovation Solution
An etching method using a plasma processing apparatus that involves forming a deposition film in recesses with different opening dimensions using specific processing gases, followed by etching the silicon-containing film using a second set of processing gases, with controlled temperature and pressure settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used on regions with different aperture dimensions, then the etching process can be completed, but the etching rates become non-uniform across different regions
Solution Approach 1:
The patent applies local quality by forming a deposition film selectively in the first recess (larger aperture) before etching. This creates a localized modification that compensates for the differences in aperture dimensions, allowing both the first recess and second recess (smaller aperture) to achieve uniform etching rates. The deposition film is formed only where needed (in the larger recess) to balance the etching characteristics across different regions.
Solution Approach 2:
The patent changes physical parameters (temperature and pressure) during the deposition process. The substrate temperature is maintained at 0°C or lower, and the chamber pressure is set higher during deposition than during etching. These parameter changes control the deposition characteristics to form a film that compensates for aperture dimension differences, thereby achieving uniform etching rates across regions with varying aperture sizes.
2Manufacturing precision
If masks with varying aperture dimensions are used to form trenches, then different trench depths can be achieved, but consistency in trench formation becomes difficult
Solution Approach 1:
The patent applies preliminary action by forming a deposition film in the first recess before the etching process. This pre-treatment modifies the surface characteristics of the larger recess, creating conditions that will result in uniform etching rates when the actual etching occurs. By performing this preparatory step, the patent ensures that subsequent etching of both recesses proceeds at consistent rates, improving trench formation consistency.
3Manufacturing precision
If the substrate temperature is lowered to 0°C or lower during deposition, then the deposition film can be formed with controlled properties, but the process complexity increases
Solution Approach 1:
The patent deliberately changes the temperature parameter to 0°C or lower during the deposition process. This parameter change enables precise control over the deposition film properties, ensuring that the film forms with characteristics that will compensate for aperture dimension differences. The controlled temperature allows for reproducible film formation, which is essential for achieving uniform etching rates across different regions.
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 method ensures uniform etching rates across regions with varying aperture dimensions, improving the consistency and precision of trench formation on semiconductor substrates.
Implementation Method 1
etching the silicon-containing film in the first recess and the second recess using plasma generated from a second processing gas within the chamber
Implementation Method 2
etched using plasma generated from a second processing gas
Implementation Method 3
forming a deposition film at least in the first recess using plasma generated from a first processing gas within the chamber
Implementation Method 4
forming a deposition film using plasma generated from a first processing gas
Data Source
AI summary
An etching method is provided. The method comprises: (a) preparing a substrate on a substrate support within a chamber, the substrate comprising a silicon-containing film having a first recess and a second recess with a smaller opening dimension than the first recess, and a mask formed on the silicon-containing film, the mask having openings that expose the first recess and the second recess; (b) forming a deposition film at least in the first recess using plasma generated from a first processing gas, wherein the first processing gas includes at least one gas selected from a group consisting of C3F6, C4F6, C4F8, isopropyl alcohol (IPA) gas, C3H2F4, and C4H2F6; and (c) etching the silicon-containing film in the first recess and the second recess using plasma generated from a second processing gas.