Silicide-Interfaced X-ray Shield Grating for Adhesion

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Solution Overview

Problem

Existing X-ray shield gratings for Talbot interferometers face issues with adhesion between metal and silicon substrates, leading to potential separation under physical forces, particularly due to metal deposition methods that result in reduced film stress and connection breakdown.

Innovation Solution

The use of silicide layers to enhance adhesion between silicon substrates and metal structures, where silicide layers are formed at the interface to improve bonding, and electroplating is employed to deposit metal within recessed portions of the substrate, ensuring strong connections and high aspect ratios for effective X-ray shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If metal is deposited by plating in recessed portions formed in a silicon substrate, then the shield portions can block X-ray radiation effectively, but the adhesion between metal and silicon substrate is reduced leading to connection breakdown

Engineering Contradiction:
ImproveX-ray radiation blockingVSAvoidadhesion between metal and silicon substrate
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a silicide layer as an intermediary between the metal shield portions and the silicon substrate. This silicide layer forms through in-situ reaction during the plating process, creating a gradient transition zone that improves adhesion. The silicide layer acts as a mediator that chemically bonds to both the metal and silicon, preventing direct metal-silicon contact that causes adhesion failure and connection breakdown under physical forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the shield portions have high aspect ratio to block X-ray radiation, then the shielding efficiency is improved, but the connection between bottom of recessed portion and metal is more prone to breaking

Engineering Contradiction:
ImproveX-ray radiation blocking efficiencyVSAvoidconnection strength at bottom of recessed portion
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent changes the chemical and physical parameters at the interface between metal and silicon by forming a silicide layer. This creates a gradual transition in material properties from metal to silicon, reducing stress concentration and improving mechanical strength. The in-situ formation process also creates a metallurgical bond that is stronger than conventional deposited interfaces, preventing connection breakdown even in high aspect ratio structures.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If metal is deposited to achieve high aspect ratio shield portions, then X-ray shielding performance is improved, but film stress is produced reducing adhesion

Engineering Contradiction:
ImproveX-ray radiation blockingVSAvoidfilm stress in metal layer
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The silicide layer serves as a stress-absorbing intermediary between the metal and silicon substrate. During the in-situ plating process, the silicide forms gradually, accommodating and distributing the film stress that develops as metal deposits in the recessed portions. This gradient structure prevents stress concentration at the metal-silicon interface, maintaining adhesion even when achieving high aspect ratios necessary for effective X-ray shielding.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 proposed solution significantly enhances the adhesion between silicon and metal components, preventing separation under physical forces and achieving high X-ray shielding efficiency with improved aspect ratios, effectively blocking 80% or more of incident X-ray radiation.

Implementation Method 1

silicide layers formed at the interfaces between the bottoms of the recessed portions and the metal layers

Methodology Applied
Scientific EffectSilicide formation: Chemical Bonding

Implementation Method 2

electroplating is employed to deposit metal within recessed portions of the substrate

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 3

metal having a high X-ray absorptance are used for nondestructive inspection, medical practice and the like

Methodology Applied
Scientific EffectX-ray absorption: Absorption (EM radiation)

Data Source

PatentEP3614398B1X-ray shield grating, method for manufacturing the same, and talbot interferometer
Publication Date: 2024.06.19 CANON KK
  • EP3614398B1 patent drawingFigure 1A~1B
  • EP3614398B1 patent drawingFigure 2A~2C
  • EP3614398B1 patent drawingFigure 3A~3D

AI summary

A structure includes a silicon substrate (1) having a plurality of recessed portions (2), each having a bottom (3) and a side wall (7), silicide layers (4), one each in contact with the bottoms of the recessed portions, and a metal structure (5) including metal portions, one each disposed in the recessed portions and in contact with the silicide layers. The silicide layers are electrically connected to each other through the silicon substrate.