Slotted Substrate for Micro-Component Adhesive Bonding

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Solution Overview

Problem

Existing methods for attaching micro-components to substrates in integrated circuit and opto-electronic assemblies face challenges in achieving precise alignment and maintaining adhesive quality over time, particularly due to environmental changes, and struggle with controlling the thin bond line thickness and adhesive flow, limiting post-placement adjustments.

Innovation Solution

The use of slotted configurations on the substrate surface allows for precise adhesive application and retention, enabling self-centering alignment and controlled curing of micro-components, with optional channels for overflow adhesive containment and localized heating to manage adhesive viscosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thin bond line is used to improve lifetime stability, then the adhesive attachment quality improves, but the adhesive flow control becomes difficult due to friction-based restriction in the molecular flow regime

Engineering Contradiction:
Improvelifetime stabilityVSAvoidadhesive flow control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The bonding surface is segmented into multiple discrete bonding sites rather than a continuous large-area bond. This segmentation reduces the total adhesive volume required and minimizes friction-based flow restriction, enabling better control of adhesive flow while maintaining thin bond lines for improved lifetime stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive bonding characteristics are optimized locally at each bonding site rather than uniformly across the entire assembly. Each bonding site can have controlled adhesive application and curing conditions, allowing precise flow control and alignment adjustment while maintaining thin bond lines for reliability.

Inventive Principle:
Principle #3Local quality

2Reliability

If a thin bond line is used to improve lifetime stability, then the adhesive attachment quality improves, but the post-placement adjustment capability is limited

Engineering Contradiction:
Improvelifetime stabilityVSAvoidpost-placement adjustment
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The bonding process is made dynamic by allowing post-placement adjustment capability. The adhesive remains adjustable for a controlled period after application, enabling alignment refinements even with thin bond lines, before final curing locks the position for long-term stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Alignment adjustments are performed preliminarily during the adjustable period before final curing. This preliminary action allows optimization of component positioning while the adhesive is still pliable, ensuring both precise alignment and long-term stability once cured.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If multiple components are placed in close proximity, then the assembly density improves, but the adhesive flow control becomes difficult due to limited space for wick-stop trenches

Engineering Contradiction:
Improveassembly densityVSAvoidadhesive flow control
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The bonding area is segmented into multiple discrete bonding sites, each with its own controlled adhesive application. This eliminates the need for extensive wick-stop trenches between components, allowing high assembly density while maintaining precise adhesive flow control at each site.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Adhesive flow control is achieved by transitioning from planar wick-stop trenches to vertical or three-dimensional containment structures at each bonding site. This dimensional change allows effective adhesive containment in limited horizontal space, enabling close component placement without sacrificing flow control.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 ensures accurate and stable attachment of micro-components with thin bond lines, reducing surface friction and enhancing joint strength while allowing for precise alignment and adjustment, even in environments subject to temperature and humidity variations.

Implementation Method 1

The well defined by the walls is filled with an adhesive material system, such as epoxy

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

reducing surface friction and allowing for the formation of thin bond lines

Methodology Applied
Scientific EffectFriction reduction: Friction

Implementation Method 3

localized heating to manage adhesive viscosity

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP2507830B1Slotted configuration for optimized placement of micro-components using adhesive bonding
Publication Date: 2021.04.21 CISCO TECHNOLOGY INC
  • EP2507830B1 patent drawingFigure 1
  • EP2507830B1 patent drawingFigure 2~3
  • EP2507830B1 patent drawingFigure 4~5

AI summary

An arrangement for improving adhesive attachment of micro-components in an assembly utilizes a plurality of parallel-disposed slots formed in the top surface of the substrate used to support the micro-components. The slots are used to control the flow and "shape" of an adhesive "dot" so as to quickly and accurately attach a micro- component to the surface of a substrate. The slots are formed (preferably, etched) in the surface of the substrate in a manner that lends itself to reproducible accuracy from one substrate to another. Other slots ("channels") may be formed in conjunction with the bonding slots so that extraneous adhesive material will flow into these channels and not spread into unwanted areas.