BEOL Resistor Structure With High-Thermal-Conductivity Insulation

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Solution Overview

Problem

Back-end-of-line (BEOL) resistors in semiconductor integrated circuits face challenges with Joule heating due to poor thermal dissipation in low-k dielectric materials, leading to compromised chip performance, as current mitigation approaches affect overall performance.

Innovation Solution

A resistor structure is developed with a first layer of electrically insulating material having high thermal conductivity (≥100 W/m/K) and a band gap of ≥4 eV, such as aluminum-nitride (AlN), boron-nitride (BN), or diamond, directly adjacent to a second layer of resistive material, along with via contacts and metal lines to enhance thermal dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If BEOL resistors are used in semiconductor integrated circuits, then the resistors can be placed further from the substrate enabling advanced circuit design, but poor thermal dissipation occurs due to surrounding low-k dielectric materials

Engineering Contradiction:

Improvecircuit design flexibilityVSAvoidthermal dissipation

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent introduces an intermediary material layer between the resistive material and the low-k dielectric environment. This intermediary layer has high thermal conductivity (≥100 W/m/K) and acts as a thermal mediator to conduct heat away from the resistor, resolving the thermal dissipation problem while maintaining the BEOL configuration flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the thermal conductivity parameter of the dielectric material surrounding the resistor by using materials with specifically controlled thermal conductivity values (first layer ≥100 W/m/K, second layer ≥20 W/m/K). This parameter change enables effective heat dissipation while maintaining the electrical insulation and structural requirements of the BEOL resistor configuration.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If high thermal conductivity materials are used to improve thermal dissipation, then Joule heating is reduced, but the material must also maintain high electrical insulation properties

Engineering Contradiction:

Improvethermal dissipationVSAvoidelectrical insulation

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent employs composite material structures where the first dielectric layer and second dielectric layer are composed of materials that simultaneously provide both high thermal conductivity and high electrical insulation. The resistive material is sandwiched between these two dielectric layers, creating a composite structure that resolves the contradiction between thermal management and electrical insulation requirements.

Inventive Principle:

Principle #40Composite materials

3Temperature

If conventional mitigation approaches are used (limiting current, setting exclusion zones, derating electromigration), then thermal dissipation is improved, but overall semiconductor chip performance is compromised

Engineering Contradiction:

Improvethermal dissipationVSAvoidchip performance

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent segments the dielectric structure into multiple layers with different thermal conductivity characteristics. The first dielectric layer directly adjacent to the resistive material has high thermal conductivity (≥100 W/m/K) for efficient heat extraction, while the second dielectric layer provides additional insulation and structural support. This segmentation allows effective thermal management without compromising chip performance.

Inventive Principle:

Principle #1Segmentation

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

The solution effectively mitigates Joule heating by improving thermal dissipation, reducing the risk of resistor failure and maintaining chip performance, while allowing for efficient electrical current flow.

Implementation Method 1

thermal conductivity of the first layer is equal to or larger than 100 W/m/K

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a first layer of electrically insulating material has a band gap equal to or larger than 4 eV

Methodology Applied

Scientific EffectBand gap insulation: Dielectric

Implementation Method 3

Joule heating caused by the BEOL resistors

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20230361158A1Resistor structure in integrated circuit

Publication Date: 2023.11.09 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments of present invention provide a resistor structure. The resistor structure includes a first layer of electrically insulating material; and a second layer of resistive material directly adjacent to the first layer, wherein thermal conductivity of the first layer is equal to or larger than 100 W/m/K. In one embodiment, the first layer of electrically insulating material has a band gap equal to or larger than 4 eV and is selected from a group consisting of aluminum-nitride (AlN), boron-nitride (BN), and diamond (C).