Masking Layer for Selective Capping in Semiconductor Devices

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Solution Overview

Problem

Current semiconductor devices face challenges in inhibiting electromigration and reducing capacitance in electrically conductive regions, as existing capping layers either allow unacceptable current leakage or increase resistance, and traditional dielectric barrier layers do not effectively adhere to conductive regions.

Innovation Solution

A masking layer is formed on the dielectric region to prevent the formation of capping layer material on or in the dielectric region, allowing for the selection of materials and processes that enhance adhesion to conductive regions without increasing resistance, and enabling the use of porous dielectric materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a capping layer is formed on electrically conductive regions to inhibit electromigration, then reliability is improved, but current leakage may occur between conductive regions

Engineering Contradiction:

Improveelectromigration inhibitionVSAvoidcurrent leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the capping layer formation process into two distinct layers: a first capping layer in direct contact with the electrically conductive regions that provides electromigration inhibition, and a second capping layer that prevents current leakage between regions. This segmentation allows each layer to specialize in one function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first capping layer acts as an intermediary between the electrically conductive regions and the second capping layer. It provides the necessary adhesion and electromigration protection while allowing the second capping layer to form a continuous barrier against current leakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a dielectric barrier layer is used to prevent current leakage, then current leakage is reduced, but adhesion to conductive regions is poor

Engineering Contradiction:

Improvecurrent leakage preventionVSAvoidadhesion to conductive regions

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent separates the adhesion function from the current leakage prevention function by using two distinct capping layers. The first capping layer is specifically designed to adhere to the electrically conductive regions, while the second capping layer provides the current leakage barrier, eliminating the need for a separate dielectric barrier layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the capping structure are assigned different properties: the first capping layer has high adhesion quality for contact with conductive regions, while the second capping layer has high insulation quality for preventing current leakage. This local differentiation optimizes both functions simultaneously.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If traditional dielectric barrier layers are used, then current leakage is controlled, but capacitance increases

Engineering Contradiction:

Improvecurrent leakage controlVSAvoidcapacitance

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent discards the traditional dielectric barrier layer approach and recovers the current leakage prevention function through a second capping layer formed of the same or similar material as the first capping layer. This eliminates the need for additional dielectric materials that would increase capacitance.

Inventive Principle:

Principle #34Discarding and recovering

4Reliability

If capping layer materials are selected to enhance adhesion to conductive regions, then reliability is improved, but resistance increases

Engineering Contradiction:

Improveadhesion enhancementVSAvoidresistance increase

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent divides the capping structure into two layers where the first capping layer uses materials optimized for adhesion and electromigration protection, while the second capping layer provides current leakage prevention. This segmentation allows the conductive regions to maintain low resistance while still achieving reliable adhesion and protection.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8343866B2Formation of a masking layer on a dielectric region to facilitate formation of a capping layer on electrically conductive regions separated by the dielectric region

Publication Date: 2013.01.01 INTERMOLECULAR INC

AI summary

A masking layer is formed on a dielectric region of an electronic device so that, during subsequent formation of a capping layer on electrically conductive regions the masking layer inhibits formation of capping layer material on the dielectric region. The capping layer can be formed selectively on the electrically conductive regions or non-selectively; in either case, capping layer material formed over the dielectric region can subsequently be removed, thus ensuring that capping layer material is formed only on the electrically conductive regions. Silane-based materials, such as silane-based SAMs, can be used to form the masking layer. The capping layer can be formed of an electrically conductive, a semiconductor material, or an electrically insulative material, and can be formed using any appropriate process, including conventional deposition processes such as electroless deposition, chemical vapor deposition, physical vapor deposition or atomic layer deposition.