Selective Catalyst Deposition for Recess Metal Wiring

Solution Overview

Problem

Existing methods for forming metal wiring layers within substrate recesses often result in unwanted metal deposition outside the recess, requiring additional chemical mechanical polishing steps, which complicates the process and reduces efficiency.

Innovation Solution

A method involving the formation of a tungsten layer on the recess bottom surface, followed by a catalyst layer and adhesion layer specifically on the tungsten within the recess, using a plating process to deposit the metal wiring layer without forming these layers on the recess surface, thereby preventing external deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a metal wiring layer is formed by plating process on a substrate recess, then the metal wiring layer can be formed within the recess, but the metal wiring layer is also formed at the outside of the recess requiring additional chemical mechanical polishing

Engineering Contradiction:

Improveease of forming metal wiring layerVSAvoidprocess complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the catalyst layer selectively present only on the tungsten layer at the bottom of the recess, while absent from the insulating layer surfaces. This localized catalyst distribution ensures that plating occurs only where needed (within the recess) and prevents unwanted metal deposition outside the recess, eliminating the need for subsequent chemical mechanical polishing steps.

Inventive Principle:

Principle #3Local quality

2Productivity

If a metal wiring layer is formed by plating process on a substrate recess, then the metal wiring layer can be formed within the recess, but the portion formed outside the recess needs to be removed by chemical mechanical polishing

Engineering Contradiction:

Improveproduction efficiencyVSAvoidprocess time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent applies local quality by making the catalyst layer selectively present only on the tungsten layer at the bottom of the recess, while absent from the insulating layer surfaces. This localized catalyst distribution ensures that plating occurs only where needed (within the recess) and prevents unwanted metal deposition outside the recess, eliminating the need for subsequent chemical mechanical polishing steps.

Inventive Principle:

Principle #3Local quality

3Reliability

If Cu is used as conductive material and buried in recess with barrier layer and seed film by electroless Cu plating, then electrical connection is achieved, but wiring volume is reduced or voids are formed

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidwiring volume precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a tungsten layer as an intermediary between the insulating layer and the catalyst layer. The tungsten layer serves as a foundation that enables selective catalyst layer formation, which in turn enables precise plating control. This intermediary structure ensures complete and uniform metal wiring layer formation within the recess, preventing voids and ensuring accurate wiring volume without compromising electrical connection reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If Ni-based metal is buried in recess by electroless plating, then wiring layer is formed, but metal layer is formed at outside of recess requiring removal

Engineering Contradiction:

Improveease of forming wiring layerVSAvoidprocess complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies local quality by making the catalyst layer selectively present only on the tungsten layer at the bottom of the recess, while absent from the insulating layer surfaces. This localized catalyst distribution ensures that plating occurs only where needed (within the recess) and prevents unwanted metal deposition outside the recess, eliminating the need for subsequent chemical mechanical polishing steps.

Inventive Principle:

Principle #3Local quality

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 allows for the easy and simple formation of metal wiring layers within the recess without external deposition, simplifying the process and eliminating the need for chemical mechanical polishing, thus enhancing efficiency and reducing the risk of voids or reduced wiring volume.

Implementation Method 1

a tungsten layer is formed on a bottom surface of the recess

Methodology Applied

Scientific Effect:

Implementation Method 2

forming a catalyst layer on the tungsten layer on the bottom surface of the recess

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

forming a metal wiring layer on the catalyst layer within the recess by a plating process

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9653354B2Metal wiring layer forming method, metal wiring layer forming apparatus, and recording medium

Publication Date: 2017.05.16 TOKYO ELECTRON LTD

AI summary

A metal wiring layer can be formed within a recess of a substrate while suppressing the metal wiring layer from being formed at the outside of the recess. A metal wiring layer forming method includes forming a catalyst layer 5 formed of Pd on a tungsten layer W on a bottom surface 3a of the recess 3 of the substrate 2 without forming the catalyst layer 5 on a surface 3b of an insulating layer of the recess 3; and forming a Ni-based metal wiring layer 7 on the catalyst layer 5 of the recess 3.