Bonded Phase Change Switch and CMOS Circuit Integration

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Solution Overview

Problem

The integration of phase change switch devices with CMOS logic circuits poses challenges due to the need for specialized processing steps for phase change materials, which are not typically included in standard CMOS workflows.

Innovation Solution

The solution involves providing a phase change switch device on a first substrate and a semiconductor circuit on a second substrate, with the two portions being bonded together. This allows for optimized manufacturing of the phase change switch device and the use of standard CMOS processes for the semiconductor circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If phase change switch device and semiconductor circuit are integrated on the same substrate, then device complexity is reduced, but manufacturing precision deteriorates due to incompatible processing steps

Engineering Contradiction:
Improveintegration complexityVSAvoidprocessing compatibility
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The device is divided into two separate portions: a first portion containing the phase change switch device on a first substrate, and a second portion containing the semiconductor circuit on a second substrate. This segmentation allows each portion to be manufactured using optimized processes for its specific requirements, with the phase change material processed separately from the CMOS circuit, thereby resolving the contradiction between integration and manufacturing precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bonding interface acts as an intermediary between the first substrate and second substrate, enabling the connection of the phase change switch device portion with the semiconductor circuit portion. This intermediary approach allows the two different processing technologies to be combined without requiring full integration on a single substrate, maintaining manufacturing precision while achieving functional integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If specialized processing steps are added to standard CMOS workflow, then manufacturing precision for phase change materials improves, but device complexity increases

Engineering Contradiction:
Improvephase change material processingVSAvoidprocessing workflow complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The manufacturing process is segmented into separate workflow streams: one for the phase change switch device requiring specialized processing steps, and another for the semiconductor circuit using standard CMOS processes. By separating these workflows and manufacturing on different substrates, the complexity of the overall processing workflow is managed while maintaining high manufacturing precision for the phase change material.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If phase change switch device is manufactured separately on different substrate, then manufacturing precision improves, but device complexity increases due to bonding process

Engineering Contradiction:
Improveprocessing optimizationVSAvoidintegration process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bonding interface serves as an intermediary that connects the separately manufactured first portion and second portion. This approach allows each portion to be optimized for its specific manufacturing requirements while the bonding process provides a standardized method for integration, managing the complexity of separate manufacturing through a well-defined connection interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The first portion and second portion are prepared in advance with appropriate bonding interfaces and connection structures before the bonding process. This preliminary preparation ensures that when the bonding occurs, the integration process is streamlined and controlled, reducing the overall complexity despite the separate manufacturing approach.

Inventive Principle:
Principle #10Preliminary action

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 creation of high-performance RF switches with reduced parasitic capacitances and improved thermal management, addressing the integration challenges faced by existing technologies.

Implementation Method 1

Phase change switches use a phase change material (PCM) which typically exhibits a higher electric conductivity in a crystalline phase state than in an amorphous phase state. By changing the phase state of the phase change material, a switch device including such a material may be switched on and off.

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

to change the phase state from amorphous to crystalline, typically a heater is employed heating the phase change material causing crystallization

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

the heater is actuated in such a way that the temperature of the PCM is raised above the melt temperature (for example above about 600°C to 900°C) followed by a comparatively rapid cooldown which freezes the phase change material or at least a portion thereof into an amorphous state

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 4

the heater is actuated in such a way that the temperature of the phase change material is above its crystallization temperature, typically about 250°C, but below the melt temperature typically in a range of 600°C to 900°C

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 5

the first portion is bonded to the second portion

Methodology Applied
Scientific EffectBonding: Welding

Data Source

PatentEP4572592A1Device comprising phase change switch device and method for providing the same
Publication Date: 2025.06.18 INFINEON TECHNOLOGIES AG
  • EP4572592A1 patent drawingFigure 1~2
  • EP4572592A1 patent drawingFigure 3A~3B
  • EP4572592A1 patent drawingFigure 4

AI summary

A device is provided, comprising a first portion (21A-21C) having a phase change switch device on a first substrate and a second portion (20) having a semiconductor circuit on a second substrate. The first and second portions are bonded together.