Terahertz Detection Element Oxide Layer Crack Prevention

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Solution Overview

Problem

Conventional terahertz-wave detection elements face challenges in achieving high spatial resolution and stability due to air bubbles in the joined parts, leading to defects and reduced detection efficiency.

Innovation Solution

A terahertz-wave detection element is manufactured using an electro-optic crystal layer and a supporting substrate joined by a resin layer, with an interposition oxide layer to prevent air bubbles, and dielectric multilayer films for reflection prevention and total reflection, ensuring high flatness and parallelism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electro-optic crystal is joined to the supporting substrate by resin adhesion without an interposition oxide layer, then the manufacturing process is simpler, but air bubbles are trapped in the joined part causing defects and reducing detection efficiency

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoiddetection efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

An interposition oxide layer is introduced between the electro-optic crystal and the supporting substrate during the resin adhesion process. This oxide layer acts as an intermediary that prevents air bubbles from being trapped in the joined part, thereby eliminating defects without complicating the manufacturing process. The oxide layer serves as a mediator that ensures reliable contact between the crystal and substrate while maintaining manufacturing simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the electro-optic crystal is made extremely thin to achieve high spatial resolution, then the diffraction influence is reduced, but the crystal becomes more susceptible to damage and manufacturing defects

Engineering Contradiction:
Improvespatial resolutionVSAvoidcrystal integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

An interposition oxide layer is applied to the electro-optic crystal before joining it to the supporting substrate. This oxide layer serves as a cushioning layer that protects the extremely thin crystal from damage during the joining process and subsequent handling. The oxide layer absorbs stress and prevents direct contact between the fragile crystal and the substrate, thereby maintaining crystal integrity while enabling the use of extremely thin crystals for high spatial resolution.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If air bubbles are present in the joined part between the electro-optic crystal and supporting substrate, then the manufacturing process is faster, but the spatial resolution and image quality are degraded

Engineering Contradiction:
Improvemanufacturing speedVSAvoidspatial resolution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The interposition oxide layer is applied in advance to the electro-optic crystal before the resin adhesion process. This preliminary action ensures that air bubbles are prevented from being trapped during joining, as the oxide layer creates a controlled interface that facilitates complete contact between the crystal and substrate. By performing this protective action beforehand, the manufacturing process maintains high speed while eliminating the defect-forming mechanism that would otherwise require additional inspection and rework steps.

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

The solution enables a crack-free terahertz-wave detection element with high spatial resolution, allowing for real-time observation of biological samples with improved image quality and reduced defects.

Implementation Method 1

there have been expected applications of the terahertz wave to an image diagnosis apparatus which non-destructively diagnoses (inspects) an object in order to utilize characteristics that photon energy is small and the frequency is higher than that of a microwave and a millimeter wave

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

sticking together a first mother substrate and a second mother substrate by an adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2899514B1Terahertz-wave detection element, production method therefor, joined body, and observation device
Publication Date: 2021.03.31 NGK INSULATORS LTD
  • EP2899514B1 patent drawingFigure 1
  • EP2899514B1 patent drawingFigure 2
  • EP2899514B1 patent drawingFigure 3

AI summary

The present invention provides a terahertz-wave detection element with high spatial resolution and suitably suppressing a crack occurrence. A method of manufacturing a terahertz-wave detection element capable of detecting a spatial intensity distribution that an incident terahertz wave has includes: an oxide formation step of forming an oxide layer on one main surface of a first substrate consisting of an electro-optic crystal in which a refractive index at an incident position of a terahertz wave changes in accordance with incident intensity of the terahertz wave; a joining step of joining the one main surface of the first substrate and a second substrate by an adhesive consisting of a thermosetting resin; a polishing step of thinning the first substrate of a joined body obtained by the joining step, to a thickness equal to or larger than 1 µm and equal to or smaller than 30 µm by polishing the first substrate; and a segmentation step of obtaining a large number of terahertz-wave detection elements by cutting the joined body into pieces of a predetermined element size. In the oxide formation step, the oxide layer is formed such that the first substrate becomes convex to a side of the one main surface by causing a tensile stress to act on the first substrate.