Reaction Tube Ceiling Design for Uniform Gas Flow

Solution Overview

Problem

Conventional reaction tubes exhibit non-uniform gas distribution in the top region due to a dome-shaped upper tubular portion, leading to stagnant gas and non-uniform film formation on substrates during semiconductor processing.

Innovation Solution

A cylindrical reaction tube with a ceiling portion having a substantially flat top inner surface and a thicker sidewall than the cylindrical portion, along with a process gas supply system and plasma generator, ensures uniform gas distribution and improved film uniformity by controlling gas flow and plasma excitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a dome-shaped upper tubular portion is used in the reaction tube, then the structural integrity is improved, but the gas distribution uniformity in the top region deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidgas distribution uniformity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The reaction tube is divided into two distinct portions: a cylindrical portion with uniform diameter and a ceiling portion with a thicker sidewall. This segmentation allows each portion to serve its specific function - the cylindrical portion ensures uniform gas flow, while the ceiling portion provides enhanced structural support at the top region.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ceiling portion is designed with a locally thicker sidewall compared to the cylindrical portion. This local quality enhancement provides additional structural strength specifically where needed at the top region, without affecting the gas flow characteristics in the cylindrical portion. The thicker sidewall maintains structural integrity while the overall cylindrical shape preserves gas distribution uniformity.

Inventive Principle:

Principle #3Local quality

2Strength

If a dome-shaped upper tubular portion is used in the reaction tube, then the structural integrity is improved, but the film uniformity across substrates deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidfilm uniformity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The reaction tube is divided into two distinct portions: a cylindrical portion with uniform diameter and a ceiling portion with a thicker sidewall. This segmentation allows each portion to serve its specific function - the cylindrical portion ensures uniform gas flow, while the ceiling portion provides enhanced structural support at the top region.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ceiling portion is designed with a locally thicker sidewall compared to the cylindrical portion. This local quality enhancement provides additional structural strength specifically where needed at the top region, without affecting the gas flow characteristics in the cylindrical portion. The thicker sidewall maintains structural integrity while the overall cylindrical shape preserves gas distribution uniformity.

Inventive Principle:

Principle #3Local quality

3Strength

If a thicker sidewall is used in the ceiling portion, then the structural strength at the top region is improved, but the device complexity increases

Engineering Contradiction:

Improvestructural strength at top regionVSAvoidreaction tube structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The ceiling portion is designed with a locally thicker sidewall compared to the cylindrical portion. This local quality enhancement provides additional structural strength specifically where needed at the top region, without affecting the gas flow characteristics in the cylindrical portion. The thicker sidewall maintains structural integrity while the overall cylindrical shape preserves gas distribution uniformity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ceiling portion features a curved top surface that transitions smoothly from the cylindrical portion. This curved design provides structural strength through geometric optimization, distributing stresses evenly without requiring additional complex support structures. The smooth transition maintains gas flow uniformity while enhancing structural integrity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances gas flow uniformity and film uniformity across substrate surfaces, reducing non-uniformity and improving processing efficiency in semiconductor device manufacturing.

Implementation Method 1

a plasma generator including an electrode in the buffer chamber; and a control unit configured to control the process gas supply system and the plasma generator to process the plurality of substrates by plasma-exciting the process gas

Methodology Applied

Scientific EffectPlasma excitation: Plasma

Data Source

PatentUS9263269B2Reaction tube, substrate processing apparatus and method of manufacturing semiconductor device

Publication Date: 2016.02.16 KOKUSAI DENKI KK

AI summary

Provided are a reaction tube, a substrate processing apparatus, and a method of manufacturing a semiconductor device capable of suppressing a non-uniform distribution of a gas in a top region to improve the flow of the gas and film uniformity within and between substrate surfaces. The reaction tube has a cylindrical shape, accommodates a plurality of substrates stacked therein, and includes a cylindrical portion and a ceiling portion covering an upper end portion of the cylindrical portion, the ceiling portion having a substantially flat top inner surface. A thickness of a sidewall of the ceiling portion is greater than that of a sidewall of the cylindrical portion.