Chip Electrode Confining Groove for Reliable Micro LED Bonding
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Solution Overview
Problem
Conventional chip bonding techniques using conductive adhesives face challenges in maintaining electrical connection, especially for micro LEDs, as conductive particles can flow with the resin, reducing the bonding area and leading to connection failures due to the smaller size of the chip's electrodes.
Innovation Solution
Incorporating confining walls around the electrodes' grooves to prevent conductive particles from being displaced by the adhesive during bonding, ensuring stable electrical connection by confining at least one conductive particle within the groove, thereby maintaining contact between the chip and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the chip size is reduced to achieve smaller device dimensions, then the device can be miniaturized, but the bonding area of electrodes is reduced leading to poor electrical connection
Solution Approach 1:
The electrode surface is segmented into multiple regions: a bonding area for adhesive application and a confining groove structure that divides the electrode into a body portion and a rim portion. This segmentation allows the limited electrode area to be functionally optimized for both bonding and electrical connection purposes.
Solution Approach 2:
The invention transitions from a planar electrode surface to a three-dimensional structure by adding vertical confining walls that form grooves. This dimensional change creates confined spaces that trap conductive particles, effectively increasing the functional bonding area without increasing the chip's planar footprint.
2Reliability
If conductive adhesive is used to achieve electrical connection, then electrical conductivity is provided, but conductive particles flow with the resin during bonding reducing connection reliability
Solution Approach 1:
The confining groove structure is pre-formed on the electrode surface before bonding occurs. This preliminary structure creates physical barriers that anticipate and prevent the harmful flow of conductive particles during the bonding process, ensuring particles remain in designated bonding areas.
Solution Approach 2:
The invention utilizes the natural flow特性 of the resin during bonding to fill the confining grooves, which in turn traps and secures the conductive particles in position. The resin's flowability, which initially causes particle displacement, is converted into a beneficial force that pushes particles into and holds them within the confining grooves.
Data Source
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AI summary
A microchip (200) is electrically connected to a substrate (100) to become a chip package, preferably for LED. A chip (200) of the package includes a body (210) and at least one electrode (220, 230) which is disposed and exposed on a surface of the body (210). The electrode (220, 230) includes a confining groove (221, 231) and a confining wall. (222, 232) The confining wall (222, 232) is peripherally located around the confining groove (221, 231) and provided to confine at least one conductive particle (310, 320) of an adhesive (300) in the confining groove (221, 231). The electrode of the chip (200) is electrically connected to a bonding pad (110, 120) of a substrate (200) via the conductive particle (310, 320) confined in the confining groove (221,231).