Mask Pattern Layout for Uniform Process Conversion

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Solution Overview

Problem

In lithography processes, variations in the cross-section shape of resist patterns lead to non-uniformity in the dimensions of processing films, affecting the uniformity and precision of semiconductor device manufacturing.

Innovation Solution

A layout method for mask patterns involves dividing the layout region into units and arranging main patterns and sub-patterns such that the distribution of exposure light attenuation differs across the divided regions, allowing for the adjustment of taper angles and process conversion differences through the strategic placement of sub-resolution assist features (SRAF) to achieve uniform process conversion differences in the processed pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sub patterns are arranged to adjust taper angles and process conversion differences, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improveuniformity of process conversion differencesVSAvoidcomplexity of mask pattern layout

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The layout region of the mask pattern is divided into multiple divided layout regions, and sub patterns are selectively arranged in specific divided regions to adjust local taper angles and process conversion differences. This segmentation approach applies complexity only where needed rather than uniformly across the entire mask pattern.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sub patterns are arranged in specific divided layout regions where process conversion differences need adjustment, rather than uniformly across the entire mask. This creates local variations in pattern density to control local taper angles and process conversion differences, improving manufacturing precision without requiring global complexity.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If sub patterns are added to resolve exposure light attenuation variations, then manufacturing precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improveuniformity of process conversion differencesVSAvoidease of mask pattern fabrication

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The mask pattern layout is segmented into divided regions based on exposure light attenuation characteristics. Sub patterns are added only in regions requiring correction, making the manufacturing process more systematic and manageable rather than requiring complex adjustments across the entire mask.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The layout region is pre-divided into multiple regions and sub patterns are pre-arranged in specific divided regions before exposure. This preliminary arrangement of sub patterns in strategic locations compensates for exposure light attenuation variations in advance, simplifying the overall manufacturing process by preventing rather than correcting defects.

Inventive Principle:

Principle #10Preliminary action

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 reduces variations in process conversion differences at the edge positions of the processed pattern without altering the dimensions of the resist pattern, enhancing the uniformity and precision of semiconductor device manufacturing.

Implementation Method 1

a main pattern H resolved by exposure light EL and arranging sub patterns HS not resolved by the exposure light EL outside the main pattern H

Methodology Applied

Scientific EffectPhotoresist exposure: Photopolymerisation

Data Source

PatentUS10120275B2Layout method of mask pattern, manufacturing method of a semiconductor device and exposure mask

Publication Date: 2018.11.06 KIOXIA CORP

AI summary

According to one embodiment, a layout region of a mask pattern is divided into N (N is an integer of 2 or larger) units, a main pattern resolved by exposure light is arranged and sub patterns not resolved by the exposure light are arranged outside the main pattern such that distributions of attenuation amount of the exposure light in the divided layout regions are different.