Low-k Dielectric Layer Etching With Nitrogen Plasma

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Solution Overview

Problem

The existing semiconductor fabrication processes face challenges in removing target layers without forming by-products that adversely affect the electrical properties of the layers and the overall electronic device.

Innovation Solution

A method involving the use of a nitrogen plasma to remove a portion of a low dielectric constant (low-k) layer in a semiconductor structure, where the nitrogen plasma is chemically unreactive with the low-k layer, thereby minimizing by-product formation and maintaining the dielectric constant and electrical resistance of the layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional plasma bombardment process is used to remove the target layer, then the removal efficiency is improved, but by-products are formed that adversely affect electrical properties

Engineering Contradiction:

Improveremoval efficiencyVSAvoidby-product formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent uses nitrogen plasma as an inert environment for etching the low-k dielectric layer. Nitrogen is chemically unreactive with the low-k material, preventing oxidation and by-product formation while maintaining effective removal of the dielectric layer through physical sputtering and ion bombardment mechanisms.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent changes the chemical composition parameter of the plasma from oxygen-based (reactive) to nitrogen-based (inert). This parameter change transforms the etching mechanism from chemical reaction-dominated to physical sputtering-dominated, eliminating harmful by-products while preserving the low-k material's electrical properties.

Inventive Principle:

Principle #35Parameter changes

2Speed

If oxygen plasma is used for etching the low-k layer, then the etching speed is improved, but oxidation occurs that alters dielectric constant and electrical resistance

Engineering Contradiction:

Improveetching speedVSAvoiddielectric constant stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

Nitrogen plasma provides an inert atmosphere during etching that prevents oxidation of the low-k dielectric layer. The inert nitrogen environment allows for controlled removal of material without chemical reactions that would alter the dielectric constant or electrical resistance, maintaining compositional stability throughout the etching process.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

Nitrogen acts as an intermediary medium that facilitates the etching process without directly reacting with the low-k material. The nitrogen plasma transfers momentum and energy through ion bombardment to remove material while the nitrogen atoms themselves remain chemically inert, serving as a mediator between the plasma source and the dielectric layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of substance

If conventional etching methods are used, then material removal is achieved, but electrical properties of the low-k layer deteriorate

Engineering Contradiction:

Improvematerial removalVSAvoidelectrical properties

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The nitrogen plasma environment enables material removal through physical sputtering mechanisms while preventing chemical reactions that would degrade electrical properties. The inert nitrogen atmosphere protects the low-k layer's molecular structure and bonding, preserving its dielectric constant and electrical resistance despite significant material removal.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent replaces chemical reaction mechanisms with physical sputtering mechanisms for material removal. Instead of using reactive plasma that chemically alters the material, the nitrogen plasma uses ion bombardment and momentum transfer to physically eject atoms from the low-k layer, maintaining electrical properties while achieving effective removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively removes the desired portion of the low-k layer without altering its dielectric constant or electrical resistance, thereby improving the performance and manufacturing efficiency of the semiconductor structure.

Implementation Method 1

providing a nitrogen plasma to collide with the portion of the first dielectric layer

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

The target layer is at least partially removed by the bombardment

Methodology Applied

Scientific EffectPhysical bombardment: Ion Beam

Data Source

PatentUS12205825B2Method of preparing semiconductor structure having low dielectric constant layer

Publication Date: 2025.01.21 NAN YA TECH

AI summary

The present application provides a method of preparing a semiconductor structure. The method includes providing a conductive film; disposing a barrier layer over the conductive film; disposing a first dielectric layer over the barrier layer; disposing a patterned hard mask over the first dielectric layer; and removing a portion of the first dielectric layer exposed through the patterned hard mask, wherein the removal of the portion of the first dielectric layer includes providing a nitrogen plasma to collide with the portion of the first dielectric layer.