Wafer-Level Microelectronic Assembly for Thermal Imagers

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Solution Overview

Problem

Current thermal far-infrared and infrared imagers require complex and costly individual production processes for their components, leading to larger sizes and higher costs, and lack efficient integration methods for sensor chips and evaluation circuits.

Innovation Solution

The production of microelectronic component arrangements at the wafer level, integrating sensor chips and evaluation circuits with lenses and vacuum structures to reduce scattering and enhance sensitivity, while allowing for compact designs and cost-effective manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If individual components are produced separately using complex production processes, then manufacturing precision can be maintained, but device complexity and production cost increase

Engineering Contradiction:
Improvecomponent precisionVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the production of the sensor chip, evaluation circuit, and lens into a single integrated component arrangement manufactured at wafer level. This integration eliminates the need for separate production processes and subsequent assembly steps, thereby reducing device complexity while maintaining manufacturing precision through unified fabrication processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor chip is designed to perform multiple functions: it contains both the sensor element for detecting infrared radiation and the evaluation circuit for processing the detected signals. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure while maintaining high manufacturing precision through integrated wafer-level production.

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

2Ease of manufacture

If components are manufactured separately and assembled, then manufacturing flexibility is maintained, but production time and cost increase

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidproduction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The sensor chip, evaluation circuit, and lens are manufactured together as an integrated assembly at wafer level, eliminating multiple separate production steps and assembly operations. This merging of manufacturing processes significantly improves productivity by producing complete functional units in a single production cycle, while maintaining ease of manufacture through standardized wafer fabrication techniques.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a vacuum is created between lens and sensor chip, then sensitivity is improved by reducing scattering, but manufacturing complexity increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidvacuum structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The vacuum structure is integrated into the component arrangement as an inherent feature rather than a separate system. The sensor chip, evaluation circuit, and lens are manufactured together with the vacuum environment built-in during wafer-level production, eliminating the need for complex external vacuum systems while maintaining high detection sensitivity through reduced radiation scattering.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If wafer level integration is implemented, then production cost and time are reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improveproduction efficiencyVSAvoidintegration precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

All components are manufactured together at wafer level in an integrated process, which inherently controls precision through unified fabrication. This approach improves productivity by eliminating separate production and assembly steps, while maintaining high integration precision through consistent wafer-level manufacturing processes that ensure accurate positioning and alignment of all components.

Inventive Principle:
Principle #5Merging (Combining)

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 compact, cost-effective thermal chip scale imagers with improved sensitivity and reduced scattering, facilitating easier integration and smaller form factors, while maintaining high thermal decoupling and efficient radiation detection.

Implementation Method 1

A vacuum is created between the lens and the sensor chip. This reduces the scattering of infrared and/or far-infrared radiation.

Methodology Applied
Scientific EffectScattering reduction in vacuum: Vacuum

Implementation Method 2

the sensor chip includes a metal mirror. This allows the IR or FIR radiation to be reflected efficiently.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The vacuum can be kept constant, for example, by direct silicon bonding between the sensor chip and the lens.

Methodology Applied
Scientific EffectSilicon bonding: Welding

Data Source

PatentEP3342147B1Microelectronic component assembly, system having a microelectronic component assembly, and corresponding production method for a microelectronic component assembly
Publication Date: 2020.04.22 ROBERT BOSCH GMBH
  • EP3342147B1 patent drawingFigure 1~2
  • EP3342147B1 patent drawingFigure 3a~3b
  • EP3342147B1 patent drawingFigure 3c~4

AI summary

The invention relates to a microelectronic component assembly (100) having a sensor chip (1) for recording thermographic images. The sensor chip (1) has a front side (VS), a back side (RS), and a lateral surface (SF), which connects the front side (VS) to the back side (RS). The microelectronic component assembly (100) also comprises at least one evaluating circuit (A1), wherein the at least one evaluating circuit (A1) is in contact with the sensor chip (1) at least in some regions on the back side (RS) and/or the lateral surface (SF) of the sensor chip (1), and a lens, wherein the lens (L1) is arranged on the front side (VS) of the sensor chip (1) and covers the sensor chip (1), wherein the lateral surface (SF) of the sensor chip (1) and/or a lateral surface (SA) of the evaluating circuit (A1) and a lateral surface (SL) of the lens (L1) have traces of mechanical removal at least in some regions.