Substrate Turntable Etching Rate Control via Rotational Speed
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Solution Overview
Problem
Existing substrate processing methods face challenges in achieving precise control over etching conditions such as etching rate and surface roughness, particularly in filling concave-shaped patterns with high aspect ratios, leading to voids and defects in films deposited on semiconductor substrates.
Innovation Solution
A substrate processing apparatus and method utilizing a turntable within a process chamber, where etching and film deposition gases are supplied in a controlled manner, with the rotational speed of the turntable adjusting to manage etching conditions, ensuring precise control over etching rates and surface roughness by alternating between film deposition and etching steps in a single process chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the reaction gas is supplied to fill narrow spaces with high aspect ratios, then the film thickness increases in the upper end region, but the film becomes thin in the bottom part region, causing void formation
Solution Approach 1:
The patent applies periodic action by alternately performing film deposition steps and etching steps in a cyclic manner. The etching step removes material from the upper end region where excess film accumulates, while the film deposition step fills the bottom part region. This periodic alternation continues until the trench is fully filled without voids, achieving uniform film thickness throughout the high aspect ratio structure.
Solution Approach 2:
The patent uses preliminary action by performing preliminary etching steps before the final film deposition. The preliminary etching removes overhangs and protrusions that form during initial deposition, creating a more favorable geometry for subsequent film filling. This prepares the substrate surface in advance to enable uniform film deposition in narrow spaces.
2Manufacturing precision
If different apparatuses are used for film deposition and etch back processes, then the film can be deposited and overhangs removed, but the throughput decreases due to wafer conveyance time
Solution Approach 1:
The patent merges the film deposition process and the etching process into a single apparatus. The same substrate processing apparatus performs both the film deposition steps and the etching steps alternately, eliminating the need to convey wafers between different apparatuses. This integration maintains the precision of void prevention while significantly improving throughput by removing transport time.
Solution Approach 2:
The substrate processing apparatus is designed with multi-functionality, capable of performing both film deposition and etching operations. By making the apparatus universal, it can execute the entire fill-trench process including both constructive (deposition) and destructive (etching) steps, thereby eliminating idle transfer time and improving overall productivity.
3Speed
If the etching gas is supplied continuously, then the etching rate increases, but the surface roughness of the film increases
Solution Approach 1:
The patent applies periodic action to the etching process by alternating between etching steps and film deposition steps. During etching steps, etching gas is supplied at high flow rates to achieve high etching rates and remove overhangs. During film deposition steps, the etching gas supply is stopped or reduced. This periodic alternation allows high etching rates without permanent surface roughness, as the subsequent deposition step smooths the surface.
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 allows for improved control over etching conditions, reducing void formation and enhancing the quality of films deposited on substrates by optimizing the balance between film deposition and etching, thereby improving the throughput and quality of semiconductor processing.
Implementation Method 1
The turntable rotates to cause the substrate placed on the turntable to pass through the process area and the purge area once per revolution, respectively
Implementation Method 2
An etching gas is supplied into the process area... A film deposited on a surface of the substrate is etched when the substrate passes the process area
Implementation Method 3
a first reaction gas is absorbed on a surface of a substrate by supplying the first reaction gas to the substrate, and then the first gas adsorbed on the surface of the substrate is caused to react with a second reaction gas
Implementation Method 4
The purge gas is supplied into the purge area
Data Source
AI summary
A method of processing a substrate is provided. A substrate is placed on a turntable provided in a process chamber. The process chamber includes a process area for supplying an etching gas and a purge area for supplying a purge gas. The process area and the purge area are arranged along a rotational direction of the turntable and divided from each other. The etching gas is supplied into the process area. The purge gas is supplied into the purge area. The turntable rotates to cause the substrate placed on the turntable to pass through the process area and the purge area once per revolution, respectively. A film deposited on a surface of the substrate is etched when the substrate passes the process are. An etching rate of the etching or a surface roughness of the film is controlled by changing a rotational speed of the turntable.