Mask Layer Etching to Reduce Metal Line Wiggling

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Solution Overview

Problem

The increasing down-scaling of integrated circuits leads to high aspect ratio stacking in photo patterning techniques, resulting in poor wiggling resistance during pattern transfer to an amorphous silicon substrate, causing line wiggling and pattern defects.

Innovation Solution

The method involves reducing the height-to-width aspect ratio of a pattern layer used to define the mask layer, resulting in a mask layer with less line wiggle, which is then transferred to subsequent layers to produce metal lines with reduced wiggle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high aspect ratio stacking is used in photo patterning techniques, then layer integration density is improved, but line wiggling resistance deteriorates

Engineering Contradiction:

Improvelayer integration densityVSAvoidline wiggling resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The mask layer is divided into multiple discrete openings rather than continuous patterns, allowing each opening to be independently optimized for etching stability. This segmentation prevents line wiggling by breaking up long continuous lines into separate, controlled features that maintain aspect ratio benefits without the wiggling problem.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent modifies the geometric parameters of the mask layer openings, specifically controlling the width and spacing to optimize the aspect ratio. By adjusting these parameters, the etching process achieves stable pattern transfer without line wiggling, resolving the contradiction between high aspect ratio benefits and wiggling resistance.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If pattern transfer is performed on amorphous silicon substrate, then device functionality is improved, but pattern defects increase due to line wiggling

Engineering Contradiction:

Improvedevice functionalityVSAvoidpattern transfer accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The mask layer is prepared in advance with pre-defined openings that account for the specific etching characteristics of amorphous silicon. This preliminary structuring ensures that when etching occurs, the pattern transfers accurately without line wiggling, preventing defects before they occur during the actual pattern transfer process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mask layer serves as an intermediary structure between the photo patterning step and the final metal interconnect pattern. By carefully designing this intermediate layer with appropriate opening geometries, it mediates the transfer process to eliminate line wiggling while maintaining compatibility with amorphous silicon substrate etching.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12322651B2Etching to reduce line wiggling

Publication Date: 2025.06.03 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for reducing wiggling in a line includes forming a first patterning layer over a metal feature and depositing a first mask layer over the first patterning layer. The first mask layer is patterned to form a first set of one or more openings therein and then thinned. The pattern of the first mask layer is transferred to the first patterning layer to form a second set of one or more openings therein. The first patterning layer is etched to widen the second set of one or more openings. The first patterning layer may be comprised of silicon or an oxide material. The openings in the first patterning layer may be widened while a mask layer is over the first patterning layer.