Angled Nozzle Head for Photomask Photoresist Removal

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Solution Overview

Problem

The spin coating process for photomasks often results in the formation of photoresist edge beads and unwanted photoresist on the sides of photomasks, leading to defects in semiconductor wafer processing.

Innovation Solution

A photomask removal apparatus featuring nozzle heads with angled flow paths and vacuum ports, coupled with a solvent supply and vacuum pump, is used to efficiently remove photoresist from selective portions of the photomask, including the peripheral edges and sidewalls, while minimizing air pockets and splashing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If spin coating process is used to apply photoresist to photomask, then photoresist can be applied to the substrate, but photoresist edge beads form on the photomask leading to defects

Engineering Contradiction:

Improvephotoresist applicationVSAvoidphotoresist edge bead formation

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by using a solvent to pre-wet the photomask surface before photoresist application, and by providing a controlled environment in the process chamber. This preparation prevents edge bead formation during spin coating by ensuring uniform photoresist distribution from the start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces solvent as an intermediary substance that mediates between the photoresist and photomask surface. The solvent creates a controlled interface that prevents direct problematic interaction between photoresist and photomask, eliminating edge bead formation while maintaining ease of manufacture.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If photoresist is applied to photomask via spin coating, then photoresist coverage is achieved, but unwanted photoresist accumulates on the sides of photomask

Engineering Contradiction:

Improvephotoresist coverageVSAvoidphotoresist residue on sides

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful photoresist residue from the photomask sides using a solvent-based removal system. The solvent selectively dissolves and removes unwanted photoresist from the sides while preserving the functional photoresist pattern, thus eliminating the harmful effect while maintaining necessary coverage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful photoresist residue into a removable substance by introducing solvent that selectively dissolves the unwanted photoresist. The same photoresist application process that creates the problem also enables the solution, as the applied photoresist can be selectively removed where unwanted, transforming the harmful accumulation into a controllable and removable state.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If conventional photoresist removal method is used, then photoresist can be removed, but air pockets and splashing occur reducing removal efficiency

Engineering Contradiction:

Improvephotoresist removal efficiencyVSAvoidair pockets and splashing

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies pneumatic principles by using a vacuum environment in the process chamber to control the solvent application and photoresist removal process. The vacuum eliminates air pockets that would interfere with solvent contact and prevents splashing by controlling vapor pressure and fluid behavior, thereby improving removal efficiency while eliminating harmful effects.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

The apparatus effectively removes photoresist from photomasks, reducing defects in semiconductor processing by providing a uniform solvent stream and preventing unwanted photoresist residue, thereby enhancing the quality of subsequent wafer processing.

Implementation Method 1

a vacuum pump coupled to the vacuum port of the first nozzle head

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

the flow path in the nozzle increases in width at an angle from the orifice to the second side

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 3

the vacuum portion includes a vacuum port extending from the second side

Methodology Applied

Scientific EffectSuction: Suction

Data Source

PatentUS11675279B2Apparatus for removing photoresist off of photomask

Publication Date: 2023.06.13 APPLIED MATERIALS INC

AI summary

Embodiments of a photomask removal apparatus for removing photoresist off of a photomask are provided herein. In some embodiments, a nozzle head for removing photoresist off of a photomask includes: a nozzle portion having a first side and an opposing second side and a flow path extending from the first side to the second side, wherein the flow path includes an orifice disposed between the first side and the second side and a nozzle that extends from the orifice to a nozzle exit on the second side, and wherein the flow path in the nozzle increases in width at an angle from the orifice to the second side; and a vacuum portion coupled to the nozzle portion, wherein the vacuum portion includes a first side and an opposing second side that faces the nozzle exit, wherein the vacuum portion includes a vacuum port extending from the second side.