Horizontal MEMS-IC Integration Using Monocrystalline Silicon

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Solution Overview

Problem

Current methods for co-integrating MEMS/NEMS with integrated circuits, such as the 'intermediate-CMOS' approach, restrict the choice of materials for MEMS structures and pose challenges in thermal management and stress optimization, limiting the performance and integration density of the devices.

Innovation Solution

A method where MEMS structures are integrated substantially 'horizontally' within the integrated circuit, using materials and layers from the CMOS process, such as semiconductor-based layers, for encapsulation, allowing for the use of monocrystalline silicon and enabling advanced microelectronic technologies without damaging the MEMS during production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the 'intermediate-CMOS' approach is used for co-integration, then the N/MEMS can be produced close to the CMOS circuit, but the choice of materials for N/MEMS structures is restricted and thermal budget constraints limit the production options

Engineering Contradiction:
Improveintegration densityVSAvoidmaterial choice
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The substrate is divided into a first portion for N/MEMS production and a second portion for CMOS circuit production, allowing independent material selection and process optimization for each component type while maintaining physical integration on the same substrate

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from vertical integration (stacking N/MEMS above CMOS) to horizontal integration (placing N/MEMS and CMOS side-by-side on the same substrate plane), enabling independent material selection while maintaining close integration for signal routing

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If N/MEMS structures are produced using metallic interconnection layers, then integration with CMOS is achieved, but residual stresses and high coefficients of thermal expansion degrade N/MEMS reliability

Engineering Contradiction:
Improveintegration processVSAvoidN/MEMS reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter from metallic interconnection layers to semiconductor-based layers (such as silicon) for N/MEMS structures, fundamentally altering the thermal and mechanical properties to reduce thermal expansion coefficients and residual stresses while maintaining CMOS compatibility through standard semiconductor fabrication processes

Inventive Principle:
Principle #35Parameter changes

3Reliability

If additional encapsulation steps are added to protect N/MEMS, then reliability against contaminants is improved, but manufacturing costs and process complexity increase

Engineering Contradiction:
Improveprotection against contaminantsVSAvoidencapsulation process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the N/MEMS encapsulation function with the CMOS circuit production process by using the same semiconductor-based layers and fabrication steps for both components, eliminating the need for separate encapsulation processes while maintaining protection and reducing overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The semiconductor-based layers serve multiple functions simultaneously: they form the structural basis for N/MEMS devices, provide encapsulation protection, and enable CMOS circuit fabrication, replacing the need for separate dedicated encapsulation layers and processes

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2215006B1Device with encapsulated integrated circuit and a n/MEMS and method for production
Publication Date: 2014.10.08 STMICROELECTRONICS (CROLLES 2) SAS
  • EP2215006B1 patent drawingFigure 1
  • EP2215006B1 patent drawingFigure 2A~2B
  • EP2215006B1 patent drawingFigure 2C~2D

AI summary

The invention relates to a method for production of a device (100), comprising at least one integrated circuit (104) and at least one N/MEMS (122), comprising at least the following steps: production of the N/MEMS in at least one upper layer (116) arranged at least above a first section of a substrate (120), production of the integrated circuit in a second section of the substrate and/or in a semiconductor layer arranged at least above the second section of the substrate and further comprising the production of a cover (124) encapsulating the N/MEMS from at least one layer used for the production of a grid (114) in the integrated circuit and/or for the production of at least one electrical contact(128, 130, 132, 134) of the integrated circuit.