MEMS Extendable Wiring for LED Chip Mounting

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Solution Overview

Problem

Conventional LED chip mounting and wire bonding processes are time-consuming and require expensive equipment, necessitating an efficient method for mounting multiple LED chips as a group while maintaining electrical connectivity.

Innovation Solution

The use of MEMS technology to form extendable metal wiring lines in a spring shape, which can be expanded or contracted to connect LED chips, eliminating the need for individual pick-and-place mounting and wire bonding processes, and allowing for flexible placement on various substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If individual LED chips are mounted using pick-and-place process, then precise placement can be achieved, but the mounting time increases and expensive equipment is required

Engineering Contradiction:
Improveplacement precisionVSAvoidmounting time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

Multiple LED chips are pre-mounted on a common carrier in a grid array pattern before being transferred to the final substrate. This combines multiple individual mounting operations into a single group transfer operation, reducing total mounting time and equipment requirements while maintaining precise placement through the structured carrier design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

LED chips are pre-positioned on a carrier substrate before the final mounting step. This preliminary arrangement allows for efficient batch processing and reduces the complexity of individual chip placement, achieving both time savings and placement accuracy through pre-organized arrays

Inventive Principle:
Principle #10Preliminary action

2Reliability

If wire bonding is performed to electrically connect LED chips, then reliable electrical connectivity is achieved, but the process becomes time consuming

Engineering Contradiction:
Improveelectrical connectivityVSAvoidconnection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Multiple LED chips are electrically connected through conductive traces formed on the carrier substrate during the pre-assembly stage. This merges multiple individual wire bonding operations into a single trace formation process, significantly reducing connection time while maintaining reliable electrical connectivity through the integrated circuit patterns

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Traditional mechanical wire bonding is replaced with conductive trace patterns formed on the substrate. This substitution eliminates the need for individual wire bonding operations while achieving reliable electrical connections through printed circuit board traces or metallization layers, dramatically reducing process time

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If rigid wiring lines are used to connect LED chips, then structural stability is maintained, but the wiring lines may be damaged during mounting or usage

Engineering Contradiction:
Improvestructural stabilityVSAvoidwiring line integrity
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent employs flexible conductive traces or thin film interconnects instead of rigid wiring lines. These flexible connections can accommodate mechanical stress and deformation during mounting and usage, preventing wire damage while maintaining electrical connectivity through the flexible conductor paths

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The wiring structure is designed with flexible elements that can dynamically adapt to mechanical stresses. The conductive traces are configured to flex and deform elastically during mounting operations and thermal expansion, maintaining structural stability while preventing permanent damage to the wiring lines

Inventive Principle:
Principle #15Dynamics

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 significantly reduces the time and cost associated with LED chip mounting and wire bonding, enabling efficient and flexible electrical connectivity of multiple LED chips on a substrate without damaging the wiring lines, and accommodating different size requirements.

Implementation Method 1

The bonding wires connecting the LED chips are made into a plurality of extendable metal wiring lines configured in a parallel direction, which can be made in a spring shape

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The extendable nature of the extendable metal wiring lines allows increasing and/or decreasing of the distance between the connected LED chips without the extendable metal wiring line being damaged or broken off during usage or mounting

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3471141B1Using MEMS fabrication incorporating into LED device mounting and assembly
Publication Date: 2021.07.21 ENNOSTAR CORP
  • EP3471141B1 patent drawingFigure 1~4
  • EP3471141B1 patent drawingFigure 5~7
  • EP3471141B1 patent drawingFigure 8~10

AI summary

LED chip packaging assembly that facilitates an integrated method for mounting LED chips as a group to be pre-wired to be electrically connected to each other through a pattern of extendable metal wiring lines is provided. LED chips which are electrically connected to each other through extendable metal wiring lines, replace pick and place mounting and the wire bonding processes of the LED chips, respectively. Wafer level MEMS technology is utilized to form parallel wiring lines suspended and connected to various contact pads. Bonding wires connecting the LED chips are made into horizontally arranged extendable metal wiring lines which can be in a spring shape, and allowing for expanding and contracting of the distance between the connected LED chips. A tape is further provided to be bonded to the LED chips, and extended in size to enlarge distance between the LED chips to exceed the one or more prearranged distances.