Polysilicon Resistance Stabilization via Nitride Barrier

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Solution Overview

Problem

In semiconductor devices, polysilicon resistance bodies and gate electrodes experience variations in resistance values and threshold voltages due to hydrogen and water release from interlayer insulation films during fabrication, limiting the design freedom for metal interconnection patterns and stability of transistor characteristics.

Innovation Solution

A semiconductor device with a polysilicon pattern covered by a metal interconnection layer pattern, where the interconnection layer is coated with silicon nitride films on its surfaces, allowing for controlled resistance values and increased design freedom by varying the nitride film thicknesses and coverage areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If metal interconnection layer pattern is formed directly on polysilicon pattern, then design freedom is improved, but resistance value stability deteriorates due to hydrogen release from interlayer insulation film

Engineering Contradiction:

Improvedesign freedomVSAvoidresistance value stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A nitride film is introduced as an intermediary layer between the metal interconnection layer pattern and the polysilicon pattern. This nitride film acts as a barrier to prevent hydrogen released from the interlayer insulation film from reaching the polysilicon pattern, thereby maintaining resistance value stability while allowing direct formation of metal interconnection patterns on polysilicon structures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The nitride film is formed in advance before depositing the metal interconnection layer pattern. This preliminary action creates a protective barrier that prevents subsequent hydrogen diffusion from affecting the polysilicon pattern, enabling design freedom without compromising stability

Inventive Principle:

Principle #10Preliminary action

2Productivity

If polysilicon pattern is covered with metal interconnection layer, then device integration is improved, but threshold voltage control deteriorates due to hydrogen diffusion

Engineering Contradiction:

Improvedevice integrationVSAvoidthreshold voltage control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The nitride film serves as a protective intermediary that prevents hydrogen from the interlayer insulation film from diffusing to the polysilicon gate electrode, thereby maintaining threshold voltage control precision while enabling device integration through metal interconnection formation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If interlayer insulation film is used for planarization, then manufacturing ease is improved, but resistance stability deteriorates due to hydrogen and water content in the film

Engineering Contradiction:

ImproveplanarizationVSAvoidresistance stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The nitride film acts as a barrier intermediary that blocks hydrogen and water molecules released from the interlayer insulation film from reaching the polysilicon pattern, thereby maintaining resistance stability while allowing the use of interlayer insulation film for planarization

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The hydrogen and water content in the interlayer insulation film, which is normally harmful, is managed by introducing the nitride film barrier that redirects or contains the released hydrogen, converting the potential harm into a controlled situation where planarization benefits are retained without resistance stability degradation

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 solution stabilizes the resistance values and threshold voltages of polysilicon patterns, enabling the free disposition of metal interconnection patterns and improving the controllability of polysilicon resistance bodies and transistors, regardless of impurity concentration levels.

Implementation Method 1

a metal interconnection layer pattern formed on the interlayer insulation film, wherein the metal interconnection layer pattern carries silicon nitride films respectively on top and bottom surfaces and sidewall surfaces thereof

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS7566607B2Semiconductor device and fabrication process thereof

Publication Date: 2009.07.28 NISSHINBO MICRO DEVICES INC

AI summary

A semiconductor device includes a semiconductor substrate, a polysilicon pattern formed on the semiconductor substrate via an insulation film, an interlayer insulation film formed on the semiconductor substrate so as to cover the polysilicon pattern, and a metal interconnection layer pattern formed on the interlayer insulation film, wherein the metal interconnection layer pattern carrying silicon nitride films respectively on a top surface, a bottom surface and sidewall surfaces thereof.