Infrared Detector Vacuum Cavity Packaging With Fewer Substrates

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Solution Overview

Problem

Existing methods for manufacturing detection devices for electromagnetic radiation in the infrared range require complex assembly of multiple substrates, leading to increased manufacturing complexity and cost.

Innovation Solution

A method that uses a single substrate for the detection structure, side wall, and cover, eliminating the need for a third substrate, and allows for a thin, optimized cover and annular side wall configuration with a sacrificial material and barrier layers for improved sealing and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If three different substrates are assembled together to form detection devices with thermally isolated structures, then the sensitivity of the detection device is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple substrates into a single substrate. The detection structure, side wall, and cover are all provided by the second substrate alone, eliminating the need for separate third substrate assembly. This integration maintains thermal isolation benefits while significantly simplifying the manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The second substrate is designed to serve multiple functions simultaneously: it provides the detection structure, forms the side wall through sacrificial material removal, and creates the cover. This multi-functional design eliminates the need for dedicated separate components for each function, reducing assembly steps.

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

2Reliability

If three different substrates are assembled together to provide thermal insulation, then the thermal isolation of the detection structure is improved, but the number of manufacturing steps increases

Engineering Contradiction:
Improvethermal isolationVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The sacrificial material is deposited and structured in advance on the second substrate before bonding to the first substrate. This preliminary action allows the cavity formation and thermal isolation structure to be prepared beforehand, eliminating the need for complex post-assembly steps and improving manufacturing efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sacrificial material acts as an intermediary element that enables cavity formation. It is deposited, patterned, and removed in a controlled sequence to create the vacuum cavity for thermal isolation, simplifying the overall manufacturing process compared to direct cavity formation methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a thin cover is provided to optimize transmission rate, then the sensitivity is improved, but the sealing and vacuum integrity become more difficult to maintain

Engineering Contradiction:
Improvetransmission rateVSAvoidvacuum integrity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection structure is nested within the cavity formed by the side wall and cover. This nested configuration allows the thin cover to be properly supported and sealed within the cavity structure, maintaining both the thinness for optimal transmission and the sealing integrity for vacuum maintenance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cover is implemented as a thin film structure that provides optimal electromagnetic radiation transmission while being integrated into the cavity. The thin film design, combined with the cavity confinement, maintains vacuum integrity despite the reduced thickness.

Inventive Principle:
Principle #30Flexible shells and thin films

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 simplifies the manufacturing process, reduces costs, and enhances the sensitivity of the detection device by optimizing the transmission rate of electromagnetic radiation while maintaining good sealing and vacuum integrity.

Implementation Method 1

house the detection structures of these devices in a cavity under at least primary vacuum

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

the structures are then thermally isolated from the rest of the device by means of connection arms

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Implementation Method 3

detection of electromagnetic radiation such as electromagnetic radiation whose wavelength is included in the infrared range

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP3441734B1Method for manufacturing a detection device having two substrates and such a detection device
Publication Date: 2024.03.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3441734B1 patent drawingFigure 1~2A
  • EP3441734B1 patent drawingFigure 2B~2C
  • EP3441734B1 patent drawingFigure 2D~3

AI summary

The invention relates to a method for manufacturing an electromagnetic radiation detection device (1). The method comprises the steps of: providing a first substrate (400) comprising a readout circuit (340), at least two first contact pads (343, 344), and at least one first annular bonding element (345) surrounding the first contact pads (343, 344); providing a second substrate comprising a hood (210), an annular side wall forming with the hood (210) a cavity filled with sacrificial material, and a detection structure (100) housed in said cavity. The method further comprises the steps of bonding the second substrate (200) to the first substrate (400); creating at least one opening (212) in the second substrate (200); selectively removing the sacrificial material; and closing said opening (212) under at least a primary vacuum.