Wafer Processing Mist Control via Continuous Gas Flow

Solution Overview

Problem

In wafer processing techniques involving mist supply, the cessation of gas flow at the end of a processing step leads to mist drifting in the furnace, causing unintended changes in the wafer surface state, which is difficult to control to a desired state.

Innovation Solution

A wafer processing apparatus that includes a furnace, a gas supplying device, a mist supplying device, and a controller to manage the flow of gas and mist. The controller stops the mist supply while continuing gas flow to prevent mist from drifting and adhering to the wafer surface, ensuring controlled surface state transitions between processing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If gas flow is stopped at the end of processing step, then energy consumption is reduced, but mist drifts in furnace causing uncontrolled wafer surface changes

Engineering Contradiction:

Improveenergy consumptionVSAvoidwafer surface state control

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The gas flow is maintained in advance during the transition period between processing steps to prevent mist from drifting onto the wafer surface. This preliminary action of keeping gas flow ensures that when mist supply stops, any remaining mist is immediately flushed out, preventing uncontrolled surface changes before the next processing step begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gas flow continues uninterrupted during the transition from one processing step to the next, maintaining a continuous protective action. The gas flow serves dual purposes: during processing it transports mist to the wafer, and during transition it flushes out remaining mist to prevent contamination, ensuring continuous control over wafer surface state.

Inventive Principle:

Principle #20Continuity of useful action

2Productivity

If mist supply is stopped immediately at end of processing step, then processing time is reduced, but wafer surface state becomes uncontrolled due to mist drift

Engineering Contradiction:

Improveprocessing speedVSAvoidwafer surface state control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The gas flow is maintained in advance during the transition period between processing steps to prevent mist from drifting onto the wafer surface. This preliminary action of keeping gas flow ensures that when mist supply stops, any remaining mist is immediately flushed out, preventing uncontrolled surface changes before the next processing step begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gas flow acts as an intermediary between mist supply and wafer surface during the transition period. It mediates by carrying away any remaining mist particles after mist supply stops, preventing direct contact between mist and wafer surface, thus controlling the surface state while allowing rapid transition.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If gas flow continues after mist supply stops, then mist drift is prevented, but energy consumption increases

Engineering Contradiction:

Improvewafer surface state controlVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The gas flow is maintained in advance during the transition period between processing steps to prevent mist from drifting onto the wafer surface. This preliminary action of keeping gas flow ensures that when mist supply stops, any remaining mist is immediately flushed out, preventing uncontrolled surface changes before the next processing step begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The gas flow operates in distinct periods: during processing steps it transports mist to the wafer, and during transition periods between steps it flushes out remaining mist. This periodic operation optimizes energy consumption by maintaining gas flow only when necessary for either mist transport or surface protection, rather than continuously.

Inventive Principle:

Principle #19Periodic action

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 effectively suppresses surface state changes at the end of processing, allowing for precise control of the wafer surface state by maintaining gas flow to flush out mist, thereby preventing unwanted adhesion and ensuring consistent processing conditions.

Implementation Method 1

controlling the gas supplying device to keep supplying the gas into the furnace

Methodology Applied

Scientific EffectGas flow: Convection

Data Source

PatentUS11699600B2Wafer processing apparatus and method for processing wafer

Publication Date: 2023.07.11 DENSO CORP

AI summary

A wafer processing apparatus is configured to process a wafer by supplying mist to a surface of the wafer. The wafer processing apparatus includes a furnace in which the wafer is disposed, a gas supplying device configured to supply gas into the furnace, a mist supplying device configured to supply the mist into the furnace, and a controller. The controller is configured to execute a processing step by controlling the gas supplying device and the mist supplying device to supply the gas and the mist into the furnace, respectively. The controller is further configured to control the mist supplying device to stop supplying the mist into the furnace while controlling the gas supplying device to keep supplying the gas into the furnace when the processing step ends.