Microelectronic Assembly With Mixed Wafer Bonding

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Solution Overview

Problem

Existing microelectronic component arrangements face challenges in miniaturization, particularly in 3D MEMS/IC integration for applications like miniaturized tire pressure monitoring systems, where achieving a compact and cost-effective stacked structure with multiple degrees of freedom is difficult due to the requirement for precise wafer/wafer bonding with same dimensions.

Innovation Solution

A microelectronic component assembly is achieved by stacking substrates with different integration degrees, utilizing a combination of wafer/wafer bonding and chip/wafer bonding processes, where substrates with digital, analog, and sensor components are bonded in a hermetically sealed frame, allowing for separate integration and encapsulation, and enabling the use of varying wafer sizes for efficient production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wafer/wafer bonding is used to stack substrates, then bonding reliability is improved, but manufacturing complexity increases due to the requirement for same wafer sizes and dimensions

Engineering Contradiction:
Improvebonding reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the substrate stacking process into two distinct bonding operations: first wafer/wafer bonding for initial substrate pairs with identical dimensions, then chip/wafer bonding for subsequent substrates with different dimensions. This segmentation allows each bonding type to operate under its optimal conditions, maintaining reliability while reducing overall manufacturing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first bonding substrate pairs with identical dimensions using wafer/wafer bonding before performing chip/wafer bonding on substrates with different dimensions. This preliminary bonding step creates stable intermediate structures that simplify subsequent bonding operations and reduce manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If substrates with different dimensions are bonded using traditional wafer/wafer bonding, then design flexibility is improved, but manufacturing precision deteriorates due to dimension mismatch

Engineering Contradiction:
Improvedesign flexibilityVSAvoidbonding precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the bonding process into two phases: first bonding substrates with identical dimensions (ensuring high precision), then bonding substrates with different dimensions using chip/wafer bonding (enabling design flexibility). This segmentation allows each phase to optimize for its specific requirement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different bonding methods for different substrate pairs: wafer/wafer bonding for substrates requiring high precision alignment, and chip/wafer bonding for substrates requiring dimensional adaptability. Each bonding location receives the appropriate method based on local requirements.

Inventive Principle:
Principle #3Local quality

3Reliability

If additional encapsulation is provided for MEMS components, then component protection is improved, but device complexity increases

Engineering Contradiction:
Improvecomponent protectionVSAvoidencapsulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the encapsulation function into the bonding frame structure itself. The bonding frame that connects substrates simultaneously serves as the encapsulation structure for MEMS components, eliminating the need for separate encapsulation layers and reducing device complexity while maintaining protection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bonding frame is designed with multi-functionality, serving both as a mechanical connection element for substrate bonding and as an encapsulation structure for protecting MEMS components. This universal structure reduces the total number of components and simplifies the overall device architecture.

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

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 results in a compact, cost-effective microelectronic component arrangement with multiple degrees of freedom, enabling miniaturization while reducing the need for additional encapsulation and allowing for the integration of diverse functionalities like digital, analog, and sensor components within a small lateral area.

Implementation Method 1

utilizing a combination of wafer/wafer bonding and chip/wafer bonding processes

Methodology Applied
Scientific EffectWafer/wafer bonding: Diffusion Welding

Implementation Method 2

utilizing a combination of wafer/wafer bonding and chip/wafer bonding processes

Methodology Applied
Scientific EffectChip/wafer bonding: Diffusion Welding

Implementation Method 3

bonded to the second substrate by means of a hermetically sealed bonding frame, as a result of which an encapsulation is formed

Methodology Applied
Scientific EffectHermetic sealing: Adhesive

Data Source

PatentEP3209600B1Microelectronic component assembly comprising a plurality of substrates, and corresponding method of production
Publication Date: 2019.11.06 ROBERT BOSCH GMBH
  • EP3209600B1 patent drawingFigure 1
  • EP3209600B1 patent drawingFigure 2a
  • EP3209600B1 patent drawingFigure 2b

AI summary

The invention relates to a microelectronic component assembly comprising a plurality of substrates, and a corresponding method of production. Said microelectronic component assembly comprising a plurality of substrates has a first substrate (C1), which is designed as a circuit substrate of a first level of integration, a second substrate (C2), which is designed as a circuit substrate of a second level of integration, and a third substrate (C3), which is designed as a MEMS sensor substrate and which is bonded onto the second substrate (C2). The second and the third substrate is bonded onto the first substrate (C1). The first level of integration is substantially higher than the second level of integration.