Nitridized Metal Resistor Structures with Varied Nitrogen Content

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Solution Overview

Problem

Conventional semiconductor resistor materials and fabrication methods face challenges such as varying sheet resistivity, limited resistance range, and inability to achieve nitrogen content greater than 50 atomic percent in metal nitride resistors due to nitrogen poisoning in deposition processes.

Innovation Solution

A semiconductor structure with two metal resistor structures having different nitrogen contents is formed by performing nitridation processes on metal layer portions, allowing for varied resistances and resistivities, achieved through specific nitridation processes and masking techniques to control nitrogen content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If physical vapor deposition is used to form metal nitride resistors, then the deposition process can be performed, but the nitrogen content is limited to less than 50 atomic percent due to nitrogen poisoning

Engineering Contradiction:

Improvenitrogen contentVSAvoiddeposition process feasibility

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the fundamental parameter of nitrogen content from limited (<50 at%) to high (>50 at%) by transitioning from physical vapor deposition to chemical vapor deposition methods, enabling the formation of metal nitride resistors with nitrogen content exceeding 50 atomic percent while maintaining process feasibility through controlled chemical reactions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/physical deposition process (physical vapor deposition) with a chemical deposition process (chemical vapor deposition), substituting the deposition mechanism to overcome the nitrogen poisoning limitation and achieve higher nitrogen content in the metal nitride resistor layer

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional resistor materials are used, then fabrication can proceed, but sheet resistivity varies beyond specifications due to poor process control

Engineering Contradiction:

Improvewafer yieldVSAvoidsheet resistivity control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements process control feedback mechanisms where sheet resistivity is measured and monitored during fabrication, and process parameters are adjusted based on measurements to maintain sheet resistivity within specifications, thereby improving wafer yield and reducing scrapping

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent controls and adjusts fabrication parameters such as deposition conditions, nitridation temperature, and nitrogen flow rates to precisely control sheet resistivity, transforming the uncontrolled variation into a controlled parameter that remains within specifications

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If doped polysilicon is used for resistors, then fabrication can proceed, but the resistance range is limited which presents problems for device miniaturization

Engineering Contradiction:

Improveresistance rangeVSAvoiddevice dimension

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent changes the material composition from doped polysilicon to metal nitride, fundamentally altering the resistivity parameter to achieve a broader resistance range that enables proper resistor functionality even in miniaturized device configurations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses metal nitride as a composite or alternative material system that combines metallic conductivity with nitride properties, providing superior adaptability for resistance control in scaled-down device dimensions compared to conventional doped polysilicon

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

This approach enables the formation of semiconductor structures with tailored resistances and resistivities, reducing the need for scrapping wafers out of specification and improving process control, thus enhancing manufacturing efficiency and reducing costs.

Implementation Method 1

A first nitridation process is then performed to provide a first nitridized metal surface layer having a first nitrogen content within the first metal layer portion

Methodology Applied

Scientific EffectNitridation: Nitriding

Data Source

PatentUS10249703B2Metal resistors having nitridized metal surface layers with different nitrogen content

Publication Date: 2019.04.02 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A semiconductor structure containing at least two metal resistor structures having different amounts of nitrogen on the resistor surface is provided. The resulted resistances (and hence resistivity) of the two metal resistors can be either the same or different. The semiconductor structure may include a first metal resistor structure located on a portion of a dielectric-containing substrate. The first metal resistor structure includes, from bottom to top, a first metal layer portion and a first nitridized metal surface layer having a first nitrogen content. The semiconductor structure further includes a second metal resistor structure located on a second portion of the dielectric-containing substrate and spaced apart from the first metal resistor structure. The second metal resistor structure includes, from bottom to top, a second metal layer portion and a second nitridized metal surface layer having a second nitrogen content that differs from the first nitrogen content.