PE-CVD Apparatus Circumferential Pumping Gap Design
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Solution Overview
Problem
Current plasma enhanced chemical vapour deposition (PE-CVD) processes face reduced throughput due to lengthy clean times caused by uneven deposition thicknesses on internal chamber surfaces, particularly evident in silicon nitride deposition at low temperatures, leading to higher costs of ownership.
Innovation Solution
The PE-CVD apparatus features a chamber design with a circumferential pumping channel, substrate support, gas inlets, and upper and lower ceramic elements that define wider second circumferential pumping gaps to enhance gas conductance, reducing pressure differentials and promoting more even deposition, thereby reducing clean times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ceramic spacers are used to limit gas conduction and achieve radial flow, then uniform deposition across the wafer is improved, but clean time increases due to uneven deposition on chamber surfaces
Solution Approach 1:
The invention changes the geometric parameters of the pumping gaps - specifically making the second pumping gap wider than the first pumping gap. This parameter modification alters the gas flow distribution and deposition pattern, reducing the unevenness that causes long clean times while maintaining acceptable wafer deposition uniformity
Solution Approach 2:
The pumping system is segmented into multiple pumping gaps (first and second pumping gaps) with different widths. This segmentation allows different regions of the chamber to have different gas conductance characteristics, optimizing both deposition uniformity and reducing material buildup on chamber surfaces
2Shape
If small pumping gaps are used to reduce gas conductance, then radial flow is achieved, but deposition uniformity deteriorates
Solution Approach 1:
The invention introduces asymmetric pumping gap widths - the second pumping gap is deliberately made wider than the first pumping gap. This asymmetric design creates a non-uniform gas flow distribution that compensates for the radial flow limitations, improving deposition uniformity across the wafer 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 design results in significantly reduced clean times from 720 to 130 seconds, improving throughput and maintaining film properties comparable to prior art, with even deposition patterns and favorable dielectric film properties.
Implementation Method 1
a plasma production device for producing a plasma in the chamber
Implementation Method 2
the upper element is spaced apart from the substrate support to confine the plasma and to define a first circumferential pumping gap... the upper and lower elements are radially spaced apart to define a second circumferential pumping gap
Implementation Method 3
plasma enhanced chemical vapour deposition (PE-CVD)
Data Source
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AI summary
According to the invention there is provided a plasma-enhanced chemical vapour deposition (PE-CVD) apparatus comprising: a chamber comprising a circumferential pumping channel; a substrate support disposed within the chamber; one or more gas inlets for introducing gas into the chamber; a plasma production device for producing a plasma in the chamber; and an upper and a lower element positioned in the chamber; wherein: the upper element is spaced apart from the substrate support to confine the plasma and to define a first circumferential pumping gap, and the upper element acts as a radially inward wall of the circumferential pumping channel; and the upper and lower elements are radially spaced apart to define a second circumferential pumping gap which acts as an entrance to the circumferential pumping channel, in which the second circumferential pumping gap is wider than the first circumferential pumping gap.