Two-Stage CVD Pressure Control for Uniform Coating

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Solution Overview

Problem

Existing CVD apparatus lack flexibility and suffer from uneven process gas distribution and pressure variations, leading to reduced coating quality and increased costs.

Innovation Solution

A CVD apparatus incorporating a pressure unit with a first pumping stage of liquid ring vacuum pumps and a second pumping stage of dry screw vacuum pumps, allowing for adjustable pressure control from 0.1 kPa to 90 kPa, and utilizing thermal energy for dissociation without plasma, combined with a pressure regulation system and valves to stabilize pressure curves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single pumping stage is used, then the device complexity is reduced, but the pressure operation range and flexibility are limited

Engineering Contradiction:

Improvepressure operation rangeVSAvoidpumping system structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pumping system is divided into two distinct pumping stages: a first pumping stage with a liquid ring vacuum pump for rough vacuum generation, and a second pumping stage with a dry screw vacuum pump for fine vacuum control. This segmentation allows each stage to be optimized for its specific pressure range, achieving a broad overall pressure operation range from 0.1 kPa to 90 kPa while maintaining manageable complexity through functional specialization.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If plasma is used for dissociation, then the dissociation efficiency is improved, but the pressure variations increase and coating quality decreases

Engineering Contradiction:

Improvecoating qualityVSAvoidpressure stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the plasma-based dissociation system with a thermally-driven dissociation system. Instead of using plasma to dissociate process gas molecules, the invention uses thermal energy from heated substrates and reactor walls to achieve dissociation. This substitution eliminates the pressure variations and instability associated with plasma generation, resulting in more stable pressure curves and improved coating quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If liquid ring vacuum pump is used alone, then the low pressure control is improved, but the delivery capacity is insufficient for high pressure ranges

Engineering Contradiction:

Improvepressure control precisionVSAvoiddelivery capacity

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

4Power

If dry screw vacuum pump is used alone, then the delivery capacity is improved, but the pressure control precision at low pressure ranges is insufficient

Engineering Contradiction:

Improvedelivery capacityVSAvoidpressure control precision

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

5Productivity

If uneven process gas distribution is present, then the gas flow rate increases, but the coating quality decreases due to inhomogeneous deposition

Engineering Contradiction:

Improvegas flow rateVSAvoidcoating uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements dynamic pressure control through the two-stage pumping system, allowing real-time adjustment of chamber pressure to optimize process gas distribution. The system can dynamically respond to changing gas flow conditions, maintaining uniform pressure distribution across the substrate surface even at high gas flow rates, thereby ensuring homogeneous coating deposition while preserving high productivity.

Inventive Principle:

Principle #15Dynamics

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

Enhances coating quality by ensuring homogeneous gas distribution and precise pressure control, reducing malfunctions and costs through improved pump reliability and efficiency.

Implementation Method 1

a first pumping stage having at least one liquid ring vacuum pump

Methodology Applied

Scientific EffectLiquid ring vacuum pump principle: Pump

Implementation Method 2

a second pumping stage having at least one dry screw vacuum pump

Methodology Applied

Scientific EffectScrew compressor principle: Pump

Implementation Method 3

CVD methods and apparatus commonly rely upon chemical reactions of chemical compounds contained in a process gas

Methodology Applied

Scientific EffectThermal dissociation: Thermolysis

Data Source

PatentUS20250207256A1Chemical vapor deposition apparatus

Publication Date: 2025.06.26 IHI BERNEX AG

AI summary

The present disclosure relates to a chemical vapor deposition apparatus for providing a surface of a substrate with a layer, the apparatus comprising: a reactor having a chamber for accommodating at least one substrate, a pressure unit configured to generate, in an inner portion of the chamber, a first predetermined pressure. The pressure unit comprises a first pumping stage having at least one liquid ring vacuum pump, and a second pumping stage having at least one dry screw vacuum pump.