Pumping Liner Aperture Segmentation for CVD Film Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chemical vapor deposition (CVD) processes face challenges in achieving uniform film thickness across a wafer due to inconsistent gas removal rates from the deposition chamber, leading to variations in film thickness and uniformity.
Innovation Solution
A pumping liner with an annular body and an array of liner apertures, where the radius of each aperture is less than 4.5 millimeters and the cumulative aperture area is less than 1,200 square millimeters, is used to facilitate a more uniform and controlled gas removal, promoting consistent exposure of the wafer to the precursor and resulting in a uniform thin film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional pumping liner with larger apertures is used, then gas removal rate is improved, but film thickness uniformity deteriorates
Solution Approach 1:
The pumping liner is segmented into multiple small apertures (at least 10, with radius less than 4.5mm each) rather than using a single large aperture or few large apertures. This segmentation distributes the gas removal function across many small openings, preventing localized high-velocity gas flows that would cause non-uniform precursor distribution and film thickness variations across the wafer surface.
Solution Approach 2:
The aperture distribution is optimized with specific spacing (center-to-center distance of at least 6mm) and size constraints (radius less than 4.5mm) to create locally uniform gas removal characteristics across different regions of the pumping liner. This ensures consistent gas velocity and precursor distribution throughout the deposition chamber, achieving uniform film thickness while maintaining adequate gas removal rate.
2Productivity
If gas removal rate is increased, then deposition efficiency is improved, but film thickness control deteriorates
Solution Approach 1:
By dividing the gas removal function into at least 10 separate small apertures, the system maintains high overall gas removal efficiency while preventing localized gas flow dominance. Each small aperture removes gas at a controlled rate, and the cumulative effect of multiple apertures achieves high deposition efficiency without creating the thickness control problems associated with fewer, larger apertures.
Solution Approach 2:
The aperture parameters (radius less than 4.5mm, center-to-center spacing of at least 6mm) are specifically optimized to balance gas removal rate with film thickness control. These parameter changes enable the system to achieve both high productivity and precise thickness control by controlling the velocity and distribution of gas flows during deposition.
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 solution ensures a more predictable and uniform film thickness across the wafer, enhancing the performance of semiconductor devices by constraining gas flow and reducing thickness gradients, thereby improving the uniformity and consistency of the thin film formed.
Implementation Method 1
a pumping liner having an annular body and an array of liner apertures defined within and penetrating through the annular body
Implementation Method 2
Chemical vapor deposition (CVD), wherein a wafer is positioned within a deposition chamber defined within a CVD assembly. A precursor is introduced into the deposition chamber to expose a surface of the wafer to the precursor and thereby form a material on the surface of the wafer
Data Source
AI summary
One or more pumping liners are provided for use in chemical vapor deposition (CVD). A pumping liner encircles a deposition chamber within which a wafer is placed and into which a precursor is introduced to form a thin film on a surface of the wafer. The pumping liner regulates a rate and uniformity at which a gas is removed from the deposition chamber, which in turn affects a duration or degree to which different portions of the wafer are exposed to the precursor. Controlling exposure of the wafer to the precursor promotes uniformity of the film formed on the wafer as well an ability to regulate the thickness of the film formed on the wafer. In an embodiment, a pumping liner has at least one of relatively small liner apertures, an increased number of liner apertures or a non-uniform distribution of liner apertures within a body of the pumping liner.