Centrifugal Wafer Processor Gas Flow Holding

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Solution Overview

Problem

Current wafer processing technologies face challenges in minimizing physical contact with the wafer during backside processing, leading to potential contamination and uneven processing results due to the use of mechanical seals or gas flows that may still reach the front side of the wafer.

Innovation Solution

A circulating gas system is used to create gas pressure and flow conditions that keep process fluids away from the front side of the wafer during backside processing, holding the wafer in place with minimal stress and reducing physical contact, thereby preventing contamination and ensuring uniform processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If mechanical seals or physical barriers are used to keep process fluids off the front side of the wafer, then the front side is protected from contamination, but the wafer is subjected to physical contact that may cause damage or particle generation

Engineering Contradiction:

Improvecontamination of front sideVSAvoidwafer damage risk

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces mechanical seals and physical barriers with a gas flow field that creates a virtual barrier. Gas flows are directed to form a protective curtain between the process fluids and the front side of the wafer, eliminating the need for mechanical contact while maintaining effective separation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses controlled gas flows to create pressure differentials and flow patterns that confine process fluids to the back side of the wafer. Gas nozzles deliver precisely controlled gas streams that form a protective barrier, using pneumatic principles to achieve separation without mechanical contact.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Object-affected harmful factors

If gas flows are used to confine process fluids to the back side, then the front side is protected from direct contact, but some process fluids still reach the front side

Engineering Contradiction:

Improveprocess fluid contact with front sideVSAvoidprocessing uniformity

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent implements different gas flow characteristics at different locations around the wafer. Gas flow rate, direction, and pressure are locally optimized to create effective barriers where needed while allowing proper processing in other areas, ensuring both protection and uniform processing.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system uses dynamic gas flow control that can be adjusted during processing. Gas flow rates and patterns are modifiable to adapt to different processing conditions, wafer positions, and fluid characteristics, maintaining effective separation throughout the dynamic processing cycle.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If the wafer is spun at high speed during back side processing, then process fluids are distributed evenly, but centrifugal forces may cause fluids to reach the front side

Engineering Contradiction:

Improvefluid distribution uniformityVSAvoidprocess fluid migration to front side

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses gas flow pressure and directional forces to counteract the centrifugal forces generated by wafer spinning. Gas nozzles deliver directed gas streams that create opposing forces to prevent process fluids from migrating toward the front side, balancing the centrifugal effects.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

Gas flows serve as an intermediary medium between the spinning wafer and the process fluids. The gas creates a protective interface that manages the interaction between centrifugal forces and fluid behavior, preventing direct fluid migration to the front side while maintaining processing effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 prevents process fluids from reaching the front side of the wafer, reducing the risk of damage and increasing wafer yield by minimizing physical contact and maintaining a clean environment, resulting in more usable device chips from each wafer.

Implementation Method 1

A circulating gas is provided on one side of the wafer. The circulating gas creates gas pressure and flow conditions that keep process fluids away from the front side

Methodology Applied

Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

The circulating gas creates gas pressure and flow conditions that keep process fluids away from the front side, during processing of the back side of the wafer

Methodology Applied

Scientific EffectGas flow: Convection

Data Source

PatentUS8104488B2Single side workpiece processing

Publication Date: 2012.01.31 APPLIED MATERIALS INC

AI summary

A centrifugal workpiece processor for processing semiconductor wafers and similar workpieces includes a head which holds and spins the workpiece. The head includes a rotor having a gas system. Gas or air is sprayed or jetted from inlets in the rotor to create a rotational gas flow. The rotational gas flow causes pressure conditions which hold the edges of a first side of the workpiece against an angled annular surface on the rotor. The rotor and the workpiece rotate together. Guide pins adjacent to a perimeter may help to align the workpiece with the rotor. Outlets through the rotor allow gas to flow out of the rotor.