Ashable Hardmask Structure for Precise Conductive Layer Patterning

Solution Overview

Problem

In semiconductor manufacturing, the wiggling of patterned features/lines in semiconductor structures is a significant issue, particularly at sub-100 nm scales, which affects the accuracy and precision of feature/line patterns.

Innovation Solution

A hardmask structure is developed, comprising a first ashable hardmask layer with a modulus greater than 130 GPa, a first anti-reflection coating, and a second ashable hardmask layer. This structure is used to form a patterned conductive layer by etching, providing excellent etching selectivity and reducing wiggling issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a hardmask structure is used for patterning conductive layers, then etching selectivity is improved, but wiggling of patterned features occurs reducing manufacturing precision

Engineering Contradiction:

Improvepattern transfer accuracyVSAvoidwiggling of patterned features

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The hardmask structure is divided into multiple layers: a bottom ashable hardmask layer with high modulus (>130 GPa) for etching selectivity, and a top ashable hardmask layer with lower modulus for pattern transfer. This segmentation allows each layer to perform its specific function optimally without compromising the other, resolving the wiggling issue while maintaining etching selectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the hardmask structure have different mechanical properties. The bottom layer is designed with high modulus to provide structural support and prevent wiggling during etching, while the top layer has lower modulus to facilitate accurate pattern transfer. This local differentiation of material properties solves the contradiction between etching selectivity and pattern accuracy.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If the modulus of the bottom hardmask layer is increased to improve etching selectivity, then pattern transfer accuracy is improved, but compressive stress increases causing wiggling

Engineering Contradiction:

Improvepattern transfer accuracyVSAvoidcompressive stress in hardmask layer

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

The hardmask structure is divided into multiple layers: a bottom ashable hardmask layer with high modulus (>130 GPa) for etching selectivity, and a top ashable hardmask layer with lower modulus for pattern transfer. This segmentation allows each layer to perform its specific function optimally without compromising the other, resolving the wiggling issue while maintaining etching selectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the hardmask structure have different mechanical properties. The bottom layer is designed with high modulus to provide structural support and prevent wiggling during etching, while the top layer has lower modulus to facilitate accurate pattern transfer. This local differentiation of material properties solves the contradiction between etching selectivity and pattern accuracy.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12272565B2Method for preparing semiconductor structure

Publication Date: 2025.04.08 NAN YA TECH

AI summary

The present disclosure provides a method for preparing a semiconductor structure using the hardmask structure. The method includes forming a conductive layer on a substrate; forming a first ashable hardmask layer on the conductive layer; forming a first anti-reflection coating on the first ashable hardmask layer; forming a second ashable hardmask layer on the first anti-reflection coating, wherein a modulus of the first ashable hardmask layer is greater than a modulus of the second ashable hardmask layer; etching the first ashable hardmask layer, the first anti-reflection coating, and the second ashable hardmask layer to transfer a first pattern to at least the first ashable hardmask layer; and etching the conductive layer according to the first ashable hardmask layer to form a patterned conductive layer.