Photomask Segmentation for Uniform Semiconductor Patterns

Solution Overview

Problem

Conventional pattern forming methods on semiconductor workpieces result in non-uniform minimum feature sizes, particularly at the edges, which affects electrical properties such as impedance matching and noise elimination.

Innovation Solution

A method involving a lithography process with a photomask having first and second apertures, where the second apertures are located between the border and the first apertures, followed by material filling and etching to form uniform second main features, which are used to create patterned features with consistent sizes, thereby improving edge uniformity and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional lithography process is used with standard photomask, then manufacturing process is simple, but minimum feature sizes are scattered especially at marginal area

Engineering Contradiction:

Improveuniformity of minimum feature sizesVSAvoidphotomask structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The photomask is divided into multiple regions with different aperture sizes. The first region contains first apertures for forming main features, while the second region contains second apertures for forming dummy features. This segmentation allows different areas of the photomask to serve different functions, improving uniformity of minimum feature sizes across the semiconductor workpiece, especially at marginal areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the photomask are designed with different aperture characteristics. The first apertures in the first region have specific size parameters for main feature formation, while the second apertures in the second region have different size parameters optimized for dummy feature formation. This local differentiation addresses the specific needs of different areas on the semiconductor workpiece.

Inventive Principle:

Principle #3Local quality

2Reliability

If conventional single-aperture photomask is used, then process is straightforward, but impedance matching process becomes ineffective due to scattered feature sizes

Engineering Contradiction:

Improveimpedance matching effectivenessVSAvoidmulti-region photomask structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The photomask is divided into multiple regions with different aperture sizes. The first region contains first apertures for forming main features, while the second region contains second apertures for forming dummy features. This segmentation allows different areas of the photomask to serve different functions, improving uniformity of minimum feature sizes across the semiconductor workpiece, especially at marginal areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the photomask are designed with different aperture characteristics. The first apertures in the first region have specific size parameters for main feature formation, while the second apertures in the second region have different size parameters optimized for dummy feature formation. This local differentiation addresses the specific needs of different areas on the semiconductor workpiece.

Inventive Principle:

Principle #3Local quality

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 method ensures uniformity of patterned features, enhancing impedance matching and noise elimination capabilities by forming consistent minimum feature sizes across the semiconductor workpiece, particularly at the edges.

Implementation Method 1

performing a lithography process on a photoresist film with a photomask having first apertures in a first mask region and second apertures in a second mask region to respectively form first main features and dummy features

Methodology Applied

Scientific EffectPhotoexposure: Photography

Implementation Method 2

exposing the photoresist film through the photomask, and forming the first main features and the dummy features by removing areas of the photoresist film exposed under the first apertures and the second apertures, respectively

Methodology Applied

Scientific EffectPhotolithography: Photography

Implementation Method 3

a substrate is etched to form patterned features by using the photoresist film having the second main features

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS9929019B2Patterns forming method

Publication Date: 2018.03.27 MICRON TECHNOLOGY INC

AI summary

A patterns forming method begins with performing a lithography process on a photoresist film with a photomask having first apertures in a first mask region and second apertures in a second mask region to respectively form first main features and dummy features, on which the second mask region is located between the border of the photomask and the first mask region, and a size of each of the first apertures is greater than a size of each of the second apertures. Subsequently, a material is filled into the first main features to respectively form second main features and into the dummy features to seal the dummy features. Then, a substrate is etched to form patterned features by using the photoresist film having the second main features.