Semiconductor Etch Residue Removal via Constant Liquid Substitution

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Solution Overview

Problem

The existing semiconductor manufacturing processes face challenges in minimizing pattern collapse during the drying of high aspect ratio features due to surface tension, particularly when using IPA, which can lead to the collapse of microfabricated device features etched into line and space patterns.

Innovation Solution

A method and apparatus for manufacturing semiconductor devices that involve a series of chemical liquid substitutions within a single processing chamber, starting with hydrofluoric acid for residue removal, followed by ultra-purified water, isopropyl alcohol, and finally dibutylether, before coating with polysilazane, all without a drying step, ensuring the workpiece remains constantly wet and reducing the risk of pattern collapse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If IPA drying is used to remove purified water from the wafer surface, then the drying process is effective, but high aspect ratio features may collapse due to surface tension

Engineering Contradiction:

Improvedrying effectivenessVSAvoidpattern collapse risk

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameter of surface tension by substituting IPA with a drying liquid having lower surface tension. This allows effective drying without the high surface tension forces that cause pattern collapse in high aspect ratio features.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a drying liquid as an intermediary substance that replaces IPA. This intermediary has the property of lower surface tension, acting as a mediator between the need for effective drying and the requirement to prevent pattern collapse.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple cleaning and drying steps are performed in separate chambers, then each process is optimized, but the number of processing steps increases

Engineering Contradiction:

Improveprocess optimizationVSAvoidnumber of processing steps

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple cleaning and drying processes into a single processing chamber. The cleaning liquid supply unit and drying liquid supply unit operate in the same chamber, combining what were previously separate steps into one integrated process, thereby reducing the total number of processing steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The processing chamber is designed to perform multiple functions: cleaning with cleaning liquid, rinsing with purified water, and drying with drying liquid. This multi-functional chamber replaces what would traditionally require multiple specialized chambers, improving productivity while maintaining process optimization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If different chemical liquids are used in the same chamber, then process integration is improved, but undesirable reactions between liquids may occur

Engineering Contradiction:

Improveprocess integrationVSAvoidundesirable reactions

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and separates the waste liquid containing mixed chemical substances from the processing chamber through a waste liquid collection unit. This removal prevents harmful reactions by taking out the potentially reactive mixture from the system after the cleaning and drying processes are complete.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent rapidly sequences the introduction of different chemical liquids (cleaning liquid, purified water, drying liquid) in a controlled manner, rushing through the potential reaction window by quickly transitioning from one liquid to the next, minimizing the time for undesirable reactions to occur.

Inventive Principle:

Principle #21Skipping (Rushing through)

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 pattern collapse in high aspect ratio features by maintaining a constant liquid presence, reducing the number of processing steps, and allowing for the use of different chemical liquids within the same chamber while ensuring separate waste collection to prevent undesirable reactions.

Implementation Method 1

cleaning etch residues residing between the etched patterns by a first chemical liquid

Methodology Applied

Scientific EffectChemical dissolution:

Implementation Method 2

IPA substitutes purified water on the wafer surface

Methodology Applied

Scientific EffectLiquid substitution:

Implementation Method 3

coating the workpiece structure rinsed by the rinse liquid with a coating liquid for formation of the insulating film

Methodology Applied

Scientific EffectChemical deposition: Deposition (physical)

Data Source

PatentUS9190262B2Method of manufacturing semiconductor device and apparatus for manufacturing semiconductor device

Publication Date: 2015.11.17 KIOXIA CORP

AI summary

A method of manufacturing a semiconductor device in which an insulating film is filled between patterns etched into a workpiece structure is disclosed. The method includes cleaning etch residues residing between the etched patterns by a first chemical liquid; rinsing the workpiece structure cleaned by the first chemical liquid by a rinse liquid; and coating the workpiece structure rinsed by the rinse liquid with a coating liquid for formation of the insulating film. The cleaning to the coating are carried out within the same processing chamber such that a liquid constantly exists between the patterns of the workpiece structure.