Dummy Substrate Geometry for Cleaning Wafer Support Edges
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in uniformly cleaning the substrate support, leading to film deposition on non-contacting and contacting surfaces, and the outer peripheral portion of the substrate support, which can generate particles due to incomplete cleaning.
Innovation Solution
A substrate processing apparatus is designed with a dummy substrate configuration where the outer peripheral portion is out of contact with the substrate placing surface, allowing for efficient cleaning using a cleaning gas that targets the non-contacting and contacting surfaces, including a modified dummy substrate with varying thickness and through-holes to enhance cleaning efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dummy substrate of the same shape as the product substrate is placed on the substrate placing surface for cleaning, then the cleaning process can be performed, but it is difficult to remove the film deposited on the outer peripheral portion of the substrate contacting surface
Solution Approach 1:
The dummy substrate is designed with an asymmetric structure where the back surface has a larger diameter than the front surface, creating an overhanging outer peripheral portion. This asymmetric geometry allows the cleaning gas to access and remove film deposits from the outer peripheral portion of the substrate contacting surface that would otherwise be blocked by a conventional symmetric dummy substrate.
Solution Approach 2:
The invention introduces a vertical dimension difference between the front and back surfaces of the dummy substrate. By making the back surface larger than the front surface, the cleaning gas can flow underneath the overhanging portion to reach the outer peripheral area of the substrate contacting surface, adding a new spatial dimension for cleaning access.
2Reliability
If the outer peripheral portion of the substrate contacting surface is not completely blocked from process gas, then film may be gradually deposited, but uniform cleaning becomes excessive on the substrate contacting surface
Solution Approach 1:
The dummy substrate design creates different cleaning conditions for different regions: the central portion of the substrate contacting surface is blocked from cleaning gas by the dummy substrate body, preventing excessive cleaning, while the outer peripheral portion is exposed to cleaning gas through the overhanging structure, enabling targeted film removal where needed.
3Object-affected harmful factors
If the film is deposited on the outer peripheral portion of the substrate contacting surface, then particles may be generated, but the cleaning process cannot effectively remove it with a conventional dummy substrate
Solution Approach 1:
The dummy substrate replicates the shape of the product substrate on the front surface to block process gas and prevent film deposition on the substrate contacting surface during normal operation. However, the back surface extends beyond the front surface to create a cleaning-specific geometry that enables removal of film from the outer peripheral portion, combining the functions of process protection and cleaning enhancement.
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 effectively removes film deposits on the outer peripheral portion of the substrate support, preventing excessive cleaning and particle generation, thereby extending the substrate support's replacement period and maintaining processing quality.
Implementation Method 1
when the film is formed on the product substrate, the film is also deposited on an exposed portion (which is not in contact with the product substrate) of a surface of the substrate support
Data Source
AI summary
There is provided a technique capable of cleaning a film deposited on an outer peripheral portion of a substrate placing surface of a substrate support. According to one aspect thereof, a substrate processing apparatus includes: a process chamber where a product substrate is processed; a substrate support provided in the process chamber and provided with a substrate placing surface whereon the product substrate is placed; a process gas supplier wherethrough a process gas is supplied into the process chamber while the product substrate being placed on the substrate placing surface; and a cleaning gas supplier wherethrough a cleaning gas is supplied into the process chamber while a dummy substrate being placed on the substrate placing surface. An outer peripheral portion of the dummy substrate is out of contact with the substrate placing surface in a state where the dummy substrate is placed on the substrate placing surface.