Preheat Ring Flow Shaping for Uniform Epitaxial Wafer Deposition

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Solution Overview

Problem

Epitaxial chemical vapor deposition (CVD) processes suffer from non-uniform growth rates across the surface of semiconductor wafers due to variability in flow rates within the reactor, leading to degradation in wafer flatness and uniformity.

Innovation Solution

A preheat ring is positioned within the reaction chamber to heat and modify the process gas before it contacts the semiconductor wafer, featuring an annular disk and edge bars that adjust the velocity, direction, and flow rate of the gas to achieve uniform deposition profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional epitaxial CVD process is used without preheat ring modification, then the process is simple and cost-effective, but the growth rate uniformity across wafer surface deteriorates due to non-uniform flow rates

Engineering Contradiction:

Improvegrowth rate uniformityVSAvoidreactor structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The preheat ring is divided into multiple heating zones with independent temperature control, allowing each segment to be optimized for specific flow rate conditions at different radial positions. This segmentation enables precise local flow rate adjustment to compensate for non-uniformities across the wafer surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preheat ring modifies the process gas parameters (temperature, velocity, pressure) before the gas contacts the wafer. By adjusting these parameters radially across the preheat ring, the system compensates for non-uniform flow rates and achieves uniform growth rates across the wafer surface.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If preheat ring with edge bar is added to adjust flow rate uniformity, then growth rate uniformity improves, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvethickness profile uniformityVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The preheat ring serves multiple functions: heating the process gas, adjusting flow rate uniformity, and controlling gas distribution across the wafer surface. By combining these functions into a single component, the system achieves uniform thickness profiles without adding multiple separate devices, thereby controlling manufacturing cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The preheat ring acts as an intermediary device between the gas inlet and the wafer surface. It modifies the process gas characteristics (temperature, velocity, pressure distribution) to ensure uniform deposition, thereby achieving uniform thickness profiles without directly modifying the wafer or requiring complex post-processing.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If process gas flow rate is increased to improve deposition speed, then productivity increases, but flow rate non-uniformity worsens leading to poorer growth uniformity

Engineering Contradiction:

Improvedeposition speedVSAvoidgrowth rate uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The preheat ring provides dynamic control of process gas parameters, allowing the system to maintain optimal flow conditions at different radial positions. This dynamic adjustment enables high overall deposition speeds while maintaining uniform growth rates across the wafer surface by compensating for local flow variations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different radial zones of the preheat ring are optimized for local conditions, with each zone providing appropriate temperature and flow rate modifications for its specific region. This local quality approach allows high deposition speeds in high-flow areas while maintaining uniformity across the entire wafer surface.

Inventive Principle:

Principle #3Local quality

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 preheat ring enhances the uniformity of epitaxial CVD growth rates, resulting in semiconductor wafers with a uniform thickness profile and reduced operational costs by minimizing local deviations and material deposition non-uniformities.

Implementation Method 1

The preheat ring is positioned within the reaction chamber for heating the process gas prior to contacting the semiconductor wafer

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

adjusting at least one of a velocity and a direction of the process gas with the edge bar

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 3

introducing a vaporous silicon source gas, such as silane or a chlorinated silane, to the front surface of the wafer to deposit and grow an epitaxial layer of silicon

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS12503792B2Methods for manufacturing a semiconductor wafer using a preheat ring in a wafer reactor

Publication Date: 2025.12.23 GLOBALWAFERS CO LTD

AI summary

A method of manufacturing a semiconductor wafer in a reaction apparatus comprising channeling a process gas into a reaction chamber through the process gas inlet and heating the process gas with the preheat ring having an edge bar. The method also includes adjusting at least one of a velocity and a direction of the process gas with the edge bar, and depositing a layer on the semiconductor wafer with the process gas, wherein the edge bar facilitates forming a uniform thickness of the layer on the semiconductor wafer.