Single Masking Process for Substrate Hole Patterning

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Solution Overview

Problem

The existing methods for forming dense and fine patterns in semiconductor devices face challenges such as misalignment and printing defects due to the limitations of double masking techniques, and struggle with high aspect ratios, making it difficult to achieve precise and uniform features.

Innovation Solution

A single masking process is employed, where a photoresist layer with island portions and spacing is formed, trimmed to enlarge the spacing, and then filled with a second material layer, allowing for precise formation of patterned layers and contact holes with features down to less than 20 nm without misalignment or printing defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If double masking technique is used to form dense patterns with fine features, then the pattern density and fineness are improved, but misalignment and printing defects occur

Engineering Contradiction:

Improvepattern finenessVSAvoidalignment accuracy

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent merges multiple masking operations into a single masking process by forming a mandrel pattern first, then using it as a template to directly form the final contact hole pattern in one exposure step. This eliminates the misalignment issues inherent in sequential double masking while maintaining the ability to form dense, fine features through the self-aligned nature of the single-step process.

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If multiple-stacked mask layers are used to obtain fine patterns, then the pattern resolution is improved, but the aspect ratio increases

Engineering Contradiction:

Improvepattern resolutionVSAvoidaspect ratio

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of multiple mask layers by using a single mask layer with a specifically designed mandrel pattern. Instead of stacking multiple mask layers to achieve fine pattern resolution, the invention uses one mask layer where the mandrel portions serve as templates, eliminating the need for additional mask layers and thereby preventing the aspect ratio from increasing.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If single masking process is used to form patterns, then the alignment accuracy and process simplicity are improved, but the ability to form dense fine patterns is limited

Engineering Contradiction:

Improvealignment accuracyVSAvoidpattern density

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the single mask layer into distinct functional regions: mandrel portions that define the pattern geometry and spacing portions that allow etch access. This segmentation enables the single mask layer to simultaneously provide alignment accuracy (through the mandrel pattern) and form dense fine patterns (through the controlled spacing regions), resolving the contradiction between process simplicity and pattern density.

Inventive Principle:

Principle #1Segmentation

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 costs, increases precision, and enables the formation of uniform and fine patterns with reduced misalignment and printing defects, achieving precise contact holes with a half pitch of less than 20 nm.

Implementation Method 1

trimming the island portion to enlarge the spacing

Methodology Applied

Scientific EffectPhotoresist trimming:

Implementation Method 2

forming a second material layer filled in the enlarged spacing and surrounding the trimmed island portion

Methodology Applied

Scientific EffectMaterial deposition: Deposition (physical)

Implementation Method 3

removing the trimmed island portion to form a first opening passing through the second material layer

Methodology Applied

Scientific EffectPhotoresist removal:

Implementation Method 4

removing the exposed portion of the first material layer through the first opening to form a second opening in the first material layer

Methodology Applied

Scientific EffectMaterial etching:

Data Source

PatentUS10832910B2Methods of fabricating a device

Publication Date: 2020.11.10 MICRON TECHNOLOGY INC

AI summary

A method for processing a substrate is provided. The method comprises forming a patterned photoresist over a first material, the patterned photoresist comprising island portions and shaped spaces surrounding the island portions. An area of each of the island portions is reduced to enlarge the shaped spaces, which are filled with a second material. The island portions are removed to form first openings in the second material. Portions of the first material exposed through the first openings are removed to form second openings in the first material. Portions of a substrate exposed through the second openings are removed to form holes in the substrate. Methods of patterning a substrate and methods of forming a hole pattern in a substrate are also disclosed.