Shower Head Alumite Coating for Film Thickness Uniformity
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Solution Overview
Problem
In film-forming processes for semiconductor wafers using ALD or CVD, fluctuations in heat reflectance of the shower head lead to inconsistent film thicknesses due to repeated exposure to film-forming and cleaning processes, affecting the reactivity and uniformity of the TiN film deposition.
Innovation Solution
A non-porous alumite coating is applied to the shower head to stabilize its heat reflectance, ensuring consistent film thickness by alleviating changes in heat reflectance and maintaining uniformity across multiple film-forming processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the shower head is made of metal without coating, then the structure is simple and easy to manufacture, but the heat reflectance fluctuates during repeated film-forming and cleaning processes
Solution Approach 1:
The shower head is constructed as a composite structure with a metal base material and a non-porous alumite coating layer. This composite design combines the structural strength of metal with the stable thermal properties of the alumite coating, resolving the contradiction between structural simplicity and heat reflectance stability.
Solution Approach 2:
The invention changes the surface properties of the shower head by applying an alumite coating, which fundamentally alters the thermal and chemical parameters of the surface. This parameter change stabilizes heat reflectance and prevents degradation during repeated processing cycles.
2Reliability
If the shower head is exposed to repeated cleaning gas processes, then the cleaning function is achieved, but the heat reflectance and film thickness uniformity deteriorate
Solution Approach 1:
The alumite coating is applied in advance to the shower head before it undergoes repeated cleaning processes. This preliminary protective action prevents the metal substrate from degrading during subsequent cleaning operations, thereby maintaining heat reflectance stability and film thickness consistency throughout the service life.
Solution Approach 2:
The non-porous alumite coating acts as an intermediary layer between the metal shower head and the cleaning gas. This intermediate layer protects the metal substrate from direct exposure to aggressive cleaning chemicals, preserving the shower head's thermal properties over extended service life.
3Stability of the object's composition
If a porous coating is applied to the shower head, then the surface area increases for better gas distribution, but the heat reflectance stability decreases due to absorption effects
Solution Approach 1:
The invention deliberately avoids using porous materials for the coating, instead selecting a non-porous alumite coating. This choice prioritizes heat reflectance stability over increased gas distribution surface area, as the non-porous structure prevents absorption effects that would destabilize thermal properties.
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 non-porous coating stabilizes the heat reflectance of the shower head, resulting in consistent TiN film thicknesses across multiple wafers, enhancing the uniformity and reactivity of the film-forming process, and preventing fluctuations in film thickness even after repeated cycles.
Implementation Method 1
a fluctuation in a heat reflectance in the shower head when the film-forming gas is supplied to each of the plurality of substrates is alleviated
Implementation Method 2
heat reflectance of the shower head... stabilizes the heat reflectance... resulting in consistent TiN film thicknesses
Implementation Method 3
a stage provided within the vacuum container and configured to heat the substrate mounted on the stage
Implementation Method 4
a gas process such as an atomic layer deposition (ALD) or chemical vapor deposition (CVD)-based film formation is performed on a semiconductor wafer
Implementation Method 5
a cleaning gas supply part configured to supply a cleaning gas into the vacuum container to clean the interior of the vacuum container
Data Source
AI summary
An apparatus includes: a vacuum container having a vacuum atmosphere for a film forming process on each substrate; a stage for heating the substrate mounted thereon; a shower head including a facing portion that faces the stage and ejection ports opened in the facing portion, which supplies a film-forming gas to the substrate through the ports so as to form a film on the substrate; a cleaning gas supply part for supplying a cleaning gas into the container to clean the interior of the container in a state where no substrate is accommodated in the container while the film forming process is applied on the each of the plurality of substrates; and a non-porous coating film for covering a base material constituting the shower head at least in the facing portion to form a surface of the shower head when the film-forming gas is supplied to each substrate.