Dual Gas Supply System for Uniform Substrate Processing

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Solution Overview

Problem

In semiconductor processing, especially during UV irradiation, conventional gas supply methods from the side walls of a reaction chamber lead to temperature and byproduct concentration gradients, causing non-uniform processing and contamination due to gas stagnation at the center.

Innovation Solution

A method involving a dual gas supply system where a first gas flows as a main stream from one side of the substrate to the opposite side, and a second gas flows as auxiliary streams from other sides to join the main stream, creating a conductance gradient that maintains uniform temperature and byproduct concentration across the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gas is supplied from side walls to form laminar flow over the substrate, then gas can be supplied without a showerhead, but temperature gradient and byproduct concentration gradient are created causing non-uniform processing

Engineering Contradiction:

Improvegas supply capability without showerheadVSAvoidprocessing uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The gas supply system is segmented into multiple independent gas supply units distributed at different locations (upstream side, downstream side, and sides) of the reaction chamber. Each unit supplies gas independently to create multiple flow streams that combine to form a flow rate gradient, allowing uniform processing without requiring a showerhead structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the reaction chamber are provided with different gas supply characteristics. The upstream side, downstream side, and side walls each have dedicated gas supply units with optimized flow rates and directions. This local differentiation creates a flow rate gradient that compensates for the long gas runway, maintaining uniform temperature and byproduct concentration across the substrate.

Inventive Principle:

Principle #3Local quality

2Temperature

If gas flow is increased to improve cooling effect, then substrate temperature can be reduced, but gas flow becomes centralized at the center causing temperature non-uniformity and byproduct accumulation

Engineering Contradiction:

Improvesubstrate cooling effectVSAvoidtemperature uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The gas supply is segmented into multiple distributed units rather than a single centralized source. By having gas supply units at the upstream side, downstream side, and sides of the reaction chamber, the cooling effect is distributed across the substrate surface. This segmentation prevents gas flow centralization at the center while maintaining effective cooling, ensuring uniform temperature distribution even at higher total gas flow rates.

Inventive Principle:

Principle #1Segmentation

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 approach ensures a substantially constant temperature and byproduct concentration along the substrate, preventing contamination and improving processing uniformity even at higher gas flow rates.

Implementation Method 1

supplying a first gas from a first side of the reaction chamber to a second side of the reaction chamber opposite to the first side so that the first gas travels, in a main stream from a first side of the substrate to a second side of the substrate opposite to the first side, over the substrate

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

supplying a second gas from sides of the reaction chamber other than the first side of the reaction chamber toward the main stream so that the second gas travels, from sides of the substrate other than the first side in a downstream direction of the main stream, over the substrate

Methodology Applied

Scientific EffectMixing:

Implementation Method 3

the first gas for cooling the substrate flows over the substrate from the first side of the substrate to the second side of the substrate opposite to the first side along the main stream, and the second gas for cooling the substrate flows over the substrate from sides other than the first side of the substrate toward the main stream along auxiliary streams

Methodology Applied

Scientific EffectHeat transfer:

Data Source

PatentUS8664627B1Method for supplying gas with flow rate gradient over substrate

Publication Date: 2014.03.04 ASM IP HLDG BV

AI summary

A method for supplying gas over a substrate in a reaction chamber wherein a substrate is placed on a pedestal, includes: supplying a first gas from a first side of the reaction chamber to a second side of the reaction chamber opposite to the first side; and adding a second gas to the first gas from sides of the reaction chamber other than the first side of the reaction chamber so that the second gas travels from sides of the substrate other than the first side in a downstream direction.