Peripheral Trench Adhesive Management for Planar Component Bonding

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Solution Overview

Problem

In the manufacture of large medical X-ray detectors, bonding planar components with stringent flatness requirements poses challenges due to surplus adhesive being squeezed out and unpredictably wicking to contaminating areas, as existing methods fail to effectively manage excess adhesive without air pockets and contamination risks.

Innovation Solution

A peripheral trench is incorporated within a support frame's recess to collect surplus adhesive, ensuring a well-defined adhesive layer thickness between planar components by applying excess adhesive and guiding it into the trench during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bonding pads are enlarged to prevent opening failures, then bonding reliability improves, but device area increases and integration density decreases

Engineering Contradiction:
Improvebonding reliabilityVSAvoiddevice area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The bonding pad structure is segmented into a central pad region and a surrounding reinforcement region. The reinforcement region includes peripheral trenches that divide the pad into multiple zones, allowing stress distribution and preventing opening failures without requiring a uniform increase in overall pad size. This segmentation enables localized reinforcement while maintaining compact overall dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different structural characteristics to different regions of the bonding pad. The peripheral trenches are strategically positioned around the pad perimeter to provide localized stress reinforcement where opening failures typically occur. This local quality enhancement targets specific weak points without increasing the area of the entire bonding pad structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If peripheral trenches are added to bonding pads, then stress distribution improves and opening failures are prevented, but manufacturing process complexity increases

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

Solution Approach 1:

The peripheral trenches are formed in the substrate before the bonding pad metallization is deposited. This preliminary action allows the trench structure to be established as a foundation, upon which the bonding pad layers are subsequently built. By performing the trench formation early in the process, the overall manufacturing complexity is reduced compared to forming trenches after pad deposition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The peripheral trenches act as an intermediary structural element between the substrate and the bonding pad metallization. These trenches provide a mechanical reinforcement interface that mediates stress distribution, preventing direct stress concentration at the pad-substrate interface. The trench structure serves as a intermediate zone that enhances bonding reliability without requiring complex multi-step reinforcement processes.

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

This method ensures a contamination-free assembly with a well-defined adhesive layer, preventing air pockets and maintaining component separation, thereby enhancing the reliability and cleanliness of the integrated device.

Implementation Method 1

random surface effects can lead to an unpredictable wicking path

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3172452B1Bonding method with peripheral trench
Publication Date: 2021.09.01 TELEDYNE DIGITAL IMAGING INC(CA)
  • EP3172452B1 patent drawingFigure 1~2

AI summary

A device has planar components forming part of a stack on a support frame, such as a substrate and upper layer, for example a fiber optic scintillator/fiber optic plate, bonded together by an adhesive layer of well-defined thickness. The device is made by providing a trench in a peripheral recess extending in a marginal portion of the support frame. Excess adhesive is applied to one of the planar components, which are then brought together such that the adhesive layer of well-defined thickness is formed between the two components and surplus adhesive is collected in the trench.