Semiconductor Wafer Developer Dispensing for Alignment Mark Exposure

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Solution Overview

Problem

Existing methods for exposing alignment marks in semiconductor manufacturing are inadequate due to material layers covering the marks, leading to misalignment issues during photolithography.

Innovation Solution

A processing apparatus and method that uses a nozzle to apply a developer over specific regions of the semiconductor wafer, rotating the wafer to position the nozzle over alignment marks, allowing for precise exposure and removal of material layers covering the marks, thereby ensuring accurate alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If material layers are deposited on alignment marks during photolithography, then the wafer structure is built up, but the alignment marks become covered or blurred causing misalignment

Engineering Contradiction:

Improvealignment precisionVSAvoidmaterial layer coverage on alignment marks

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the wafer surface into two distinct zones: a first region containing the alignment marks that remains free of material layers, and a second region where material layers are deposited for device fabrication. This spatial segmentation allows alignment marks to remain visible and precise while still enabling material deposition elsewhere on the wafer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different surface properties to different regions of the wafer. The first region containing alignment marks is maintained with a specific surface property that prevents material layer adhesion, while the second region has properties that allow material deposition. This local differentiation ensures alignment marks remain uncovered while enabling fabrication in other areas.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If developer is applied over the entire wafer surface to expose alignment marks, then alignment marks are uncovered, but developer usage is excessive and hazardous waste increases

Engineering Contradiction:

Improvealignment mark exposureVSAvoiddeveloper consumption

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies developer selectively only to the first region containing alignment marks, rather than flooding the entire wafer surface. This localized application is enabled by the hydrophobic coating on the second region that repels the aqueous developer solution, causing it to remain confined to the first region where alignment marks are located.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a hydrophobic coating as an intermediary substance on the second region of the wafer. This coating acts as a barrier that prevents developer from spreading to areas where it is not needed, thereby reducing overall developer consumption and hazardous waste while still allowing complete exposure of alignment marks in the first region.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If material layers are removed from alignment marks, then alignment precision is improved, but additional processing steps are required

Engineering Contradiction:

Improvealignment mark visibilityVSAvoidprocessing steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies a hydrophobic coating to the second region of the wafer before any material layer deposition or photolithography steps. This preliminary action creates a permanent boundary that prevents material layers from forming on alignment marks in the first region, eliminating the need for subsequent removal steps and simplifying the overall process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of material layer deposition into a benefit by using the deposition process itself to define region boundaries. The hydrophobic coating causes material layers to naturally form only in the second region, and causes developer to naturally confine to the first region during photolithography, thereby achieving alignment mark exposure without additional removal steps.

Inventive Principle:

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

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 uncovers alignment marks, enabling precise alignment during photolithography, reduces developer usage by 80%, and enhances processing efficiency, minimizing hazardous waste and extending tool capacity.

Implementation Method 1

dispensing developer over the semiconductor wafer relative to alignment marks formed on the semiconductor wafer

Methodology Applied

Scientific EffectDispensing:

Implementation Method 2

rotating the semiconductor wafer by a dispensing rotation angle

Methodology Applied

Scientific EffectRotation:

Data Source

PatentUS9941131B1Method for applying developer on semiconductor wafer

Publication Date: 2018.04.10 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for applying developer over a semiconductor wafer is provided. The method includes moving a nozzle over the center of the semiconductor wafer. The nozzle extends across the semiconductor wafer. The method also includes rotating the semiconductor wafer by a dispensing rotation angle that is less than 180 degrees. The method further includes dispensing developer over the semiconductor wafer relative to alignment marks formed on the semiconductor wafer while the semiconductor wafer is rotated by the dispensing rotation angle.