Holed Plate for Uniform Gas Distribution in Semiconductor Deposition
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Solution Overview
Problem
Conventional vertical apparatuses for forming semiconductor devices exhibit non-uniform deposition rates across wafers, with those at the upper portion experiencing significantly lower deposition rates compared to central or lower portions, due to pressure gradients within the chamber.
Innovation Solution
The apparatus includes an inner tube surrounded by an outer tube, with a plate having through-holes that occupy 10 to 60% of the plate's area, allowing gas to flow uniformly and minimizing pressure gradients, ensuring even gas distribution across the wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vertical apparatus is used to simultaneously treat multiple wafers, then productivity is improved, but deposition uniformity deteriorates due to pressure gradients
Solution Approach 1:
The gas supply system is segmented into multiple zones using a plate with multiple holes distributed across its surface. This plate divides the gas flow into multiple streams that reach different radial positions of the wafers, ensuring uniform deposition across all wafers stacked vertically in the inner tube.
Solution Approach 2:
The plate structure provides different gas flow characteristics at different locations. By positioning the plate at a specific height and using holes of appropriate sizes and distributions, the gas flow is locally optimized to compensate for the pressure gradient effect, ensuring each wafer receives adequate gas supply regardless of its vertical position.
2Productivity
If gas flows vertically through the chamber, then deposition rate at central portion is improved, but deposition rate at edge portion deteriorates
Solution Approach 1:
The gas supply is segmented into multiple radial zones through the plate structure. The holes in the plate are positioned to create gas flow paths that reach both central and edge portions of the wafers, ensuring uniform deposition across the entire wafer surface by compensating for the radial pressure gradient.
3Manufacturing precision
If the plate area is increased to improve gas distribution, then pressure gradient compensation is improved, but gas flow rate to wafers deteriorates
Solution Approach 1:
The plate area ratio is optimized to a specific range (10-60% of the inner tube cross-sectional area) to balance two competing requirements: sufficient area to distribute pressure uniformly across the wafer stack, and sufficient open space to maintain adequate gas flow rate. This parameter optimization resolves the contradiction between pressure uniformity and gas flow rate.
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 configuration enhances deposition uniformity by increasing gas pressure at the upper portion and reducing variations, resulting in improved deposition rates and uniformity across all regions of the wafers.
Implementation Method 1
minimize pressure gradients in a plurality of regions inside the inner tube
Implementation Method 2
supplying gas such that the gas flows from a first portion of the inner tube toward a second portion of the inner tube uniformly over the surfaces of the plurality of wafers
Implementation Method 3
forming a thin film on a substrate of the wafer by supplying gas
Data Source
AI summary
An apparatus to form semiconductor devices includes an inner tube and an outer tube disposed to surround the inner tube. A plate is disposed at first open end of the inner tube to reduce variation between pressures at a first portion and a second portion inside the inner tube. The sum of areas of through-holes disposed on the plate is 10 to 60 percent of the entire area of the plate. The through-holes may include a first through-hole that is disposed at a central portion of the plate, and second through-holes disposed at an edge portion of the plate. The second through-holes are annularly arranged to surround the first through-hole.