Antireflective Coating for Via Formation in Semiconductor Interconnections

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Solution Overview

Problem

Via miss defects occur during the patterning of low-K dielectric layers in interconnection structures, leading to incomplete or absent vias, which affect the yield and reliability of electrical connections in semiconductor manufacturing.

Innovation Solution

The method involves forming an antireflective coating on the dielectric layer to reduce lithographic light reflection, using a second mask to pattern through holes, and filling these holes with conductive material, thereby preventing photoresist residue and ensuring complete penetration of vias through the dielectric layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mask layer is used to pattern the low-K dielectric layer, then the through holes can be formed, but via miss defects occur due to photoresist residue from lithographic light reflection

Engineering Contradiction:

Improvevia formation completenessVSAvoidelectrical connection reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

An antireflective coating layer is introduced as an intermediary between the mask layer and the low-K dielectric layer. This coating specifically addresses the lithographic light reflection problem by absorbing excess light, preventing photoresist residue formation, and ensuring complete via penetration without compromising the electrical connection reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The antireflective coating is applied in advance before the photolithography patterning step. This preliminary action prevents the formation of photoresist residue by eliminating light reflection issues before they can affect the via formation process, thereby ensuring complete via penetration and improving manufacturing precision

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If photoresist residue remains in the through hole pattern, then incomplete vias are formed, but yield of the interconnection structure decreases

Engineering Contradiction:

Improvevia penetration completenessVSAvoidinterconnection structure yield

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The antireflective coating serves as a mediator that eliminates the root cause of photoresist residue by absorbing lithographic light. This ensures complete via penetration and eliminates via miss defects, directly improving the yield of the interconnection structure by preventing defective devices

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of lithographic light reflection (which causes photoresist residue) into a benefit by using the antireflective coating to absorb the excess light. This transforms a process defect into a controlled parameter, ensuring complete via formation and improving overall manufacturing yield

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances the yield of interconnection structures by preventing photoresist residue and ensuring complete formation of vias, thereby improving the reliability of electrical connections in semiconductor devices.

Implementation Method 1

forming an antireflective coating on the dielectric layer... wherein the antireflective coating significantly reduces lithographic light reflection to avoid photoresist residue

Methodology Applied

Scientific EffectLight reflection reduction: Anti-Reflective Coating

Data Source

PatentUS9190317B2Interconnection structures and fabrication method thereof

Publication Date: 2015.11.17 SEMICON MFG INT (SHANGHAI) CORP

AI summary

A method is provided for fabricating an interconnection structure. The method includes providing a substrate having certain semiconductor devices, a metal layer electrically connecting with the semiconductor devices, and a barrier layer on the metal layer. The method also includes forming a dielectric layer on the substrate; and forming an antireflective coating on the dielectric layer. Further, the method includes forming a second mask having a first pattern corresponding to a through hole in the dielectric layer, wherein the antireflective coating significantly reduces lithographic light reflection to avoid photoresist residue in the first pattern; and forming a through hole by etching the dielectric layer and the antireflective coating covering the dielectric layer using the second mask as an etching mask. Further, the method also includes forming a via by filling the through hole with a conductive material.