Ramp VIA Anti-Reflection Structure for Accurate Trench Patterning

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Solution Overview

Problem

The reflection of light from sloped ramp VIAs during photoresist patterning leads to improper patterning and potential formation of trench metal bridges, affecting the adhesion and stress buffering in BEOL processes.

Innovation Solution

Incorporation of anti-reflection components, such as conical or pyramidal shaped silicon oxynitride, on ramp VIAs to absorb or deflect light, preventing reflection and ensuring accurate photoresist patterning, thereby avoiding trench metal bridges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If sloped ramp VIAs are used to increase surface adhesion to trench metal components, then adhesion is improved, but light reflection occurs during photoresist patterning leading to improper patterning

Engineering Contradiction:

ImproveadhesionVSAvoidpatterning accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

An anti-reflection component is introduced as an intermediary element positioned between the sloped ramp VIA and the photoresist layer. This component absorbs or scatters incident light, preventing it from reflecting off the sloped VIA surface onto the photoresist, thereby eliminating patterning defects while preserving the underlying adhesion benefits of the sloped structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sloped VIA structure inherently causes light reflection that harms patterning accuracy. The invention converts this harmful reflection issue into a benefit by deliberately adding an anti-reflection component that exploits the same sloped geometry to its advantage - the anti-reflection component is shaped to match and enhance the light-absorbing/scattering effect, turning the problematic light interaction into a controlled anti-reflection mechanism.

Inventive Principle:

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

2Strength

If sloped ramp VIAs are used to improve adhesion, then adhesion is improved, but trench metal bridges may form due to improper patterning

Engineering Contradiction:

ImproveadhesionVSAvoiddevice yield

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The anti-reflection component serves as a protective intermediary that prevents light-induced patterning errors during the trench metal formation process. By blocking the harmful light reflection path, it ensures that the photoresist pattern accurately defines the trench metal boundaries, preventing unintended metal bridge formation and improving device reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The anti-reflection component is formed on the sloped ramp VIA surface before the photoresist patterning step. This preliminary action prepares the surface by eliminating the light reflection problem in advance, ensuring that subsequent patterning operations proceed without defects that could lead to metal bridge formation.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If anti-reflection components are added to prevent light reflection, then patterning accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvepatterning accuracyVSAvoidstructure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The anti-reflection component is applied locally only to the critical sloped ramp VIA regions where light reflection causes patterning problems. Rather than modifying the entire device structure, the solution is localized to specific areas needing correction, minimizing the increase in overall device complexity while achieving the desired patterning improvement.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The anti-reflection component is formed using a composite material structure - typically a dielectric material deposited conformally on the sloped VIA surface. This composite approach combines the structural integrity of the underlying VIA with the optical properties of the dielectric layer, achieving anti-reflection functionality without requiring entirely new materials or complex multi-layer structures.

Inventive Principle:

Principle #40Composite materials

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

Enhances the adhesion of trench metal components and reduces the risk of short circuits by preventing improper patterning, improving device yield and performance.

Implementation Method 1

Incorporation of anti-reflection components, such as conical or pyramidal shaped silicon oxynitride, on ramp VIAs to absorb or deflect light, preventing reflection

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20250233014A1Semiconductor device structure and method of fabricating same

Publication Date: 2025.07.17 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device structure and method that utilizes anti-reflection components. The structure includes at least one ramp VIA formed in a VIA isolator layer, at least one anti-reflection component formed on the at least one ramp VIA. A trench isolator layer is formed on the at least one anti-reflection component, and a photoresist is selectively patterned on the trench isolator layer. The trench isolator layer and a portion of the at least one anti-reflection component is etched based upon the selectively patterned photoresist to form a trench metal component hole above the at least one ramp VIA. Thereafter, a trench metal component is formed in the trench metal component hole.