Profiled Thermode Recess Geometry for FlexIC Bonding
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Solution Overview
Problem
Thermodes used for connecting flexible integrated circuits (FlexICs) with conductive adhesive risk causing electrical shorting or damage due to conductive particles being pressed into the FlexIC's circuits, as they apply high pressure that can exceed the thickness of the adhesive, potentially puncturing the thin protective layer.
Innovation Solution
A thermode design featuring a tip with recessed contact surface portions and a supporting surface portion that can move relative to each other to apply heat and pressure, forming a bonding zone without pressing conductive particles into the FlexIC, with the recess providing space to prevent damage and ensure even heating, reducing the risk of electrical shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high pressure is applied by the thermode to squeeze the adhesive between the FlexIC and circuit, then the adhesive bonding is improved, but the conductive particles may be pressed into the FlexIC's circuits causing electrical shorting or damage
Solution Approach 1:
The thermode tip is designed with different local properties: a recessed region with reduced pressure application for areas overlying FlexIC circuitry, and elevated contact regions for applying pressure over adhesive areas. This spatial variation in pressure distribution allows strong bonding where needed while protecting sensitive circuits from particle intrusion.
Solution Approach 2:
The thermode tip surface is segmented into multiple zones with different pressure characteristics - recessed zones for circuit protection and elevated zones for bonding enhancement. This segmentation allows independent optimization of bonding strength and circuit protection in different spatial locations.
2Manufacturing precision
If the thermode applies sufficient pressure to make the adhesive thinner than the conductive particles, then proper bonding is achieved, but the thin protective layer of FlexIC may be punctured
Solution Approach 1:
The thermode incorporates a recessed region that locally reduces pressure application over areas corresponding to FlexIC circuitry and protective layers. This localized pressure reduction prevents puncture of the thin protective layer while elevated regions maintain sufficient pressure for proper adhesive bonding in appropriate areas.
3Ease of operation
If uniform pressure is applied across the entire thermode contact surface, then the bonding process is simple, but the conductive particles may be pressed into the FlexIC circuits
Solution Approach 1:
The thermode tip features a recessed region that creates a localized low-pressure zone over FlexIC circuitry areas, while elevated contact regions maintain higher pressure for bonding. This spatially differentiated pressure distribution is achieved through the physical geometry of the thermode tip itself, maintaining operational simplicity while preventing circuit damage.
4Temperature
If the thermode contact surface is flat, then heat distribution is efficient, but the conductive particles may be pressed into the FlexIC's thin protective layer
Solution Approach 1:
The thermode tip combines a generally flat configuration for efficient heat distribution with a localized recessed region that reduces pressure over areas corresponding to FlexIC circuitry. This allows maintained thermal contact for heating while creating a pressure relief zone that prevents particle intrusion into the protective layer.
Solution Approach 2:
The recessed region in the thermode tip introduces a curved or contoured surface feature that reduces contact pressure in specific areas. This curvature creates a pressure gradient that protects the FlexIC protective layer while maintaining overall thermal coupling through the predominantly flat thermode surface.
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 thermode effectively connects FlexICs and application circuits without damaging the flexible components, ensuring a secure bond while preventing conductive particles from puncturing the circuitry, thus maintaining the integrity of the electronic circuits.
Implementation Method 1
efficient heat transfer occurs and rapid heating of the component is possible
Implementation Method 2
localized heating is typically produced by direct resistance heating of the contact surface of the thermode
Data Source
AI summary
The invention relates to a thermode for connecting at least two components, comprising a tip having a body portion with at least two contact surface portions connected to and spaced apart from one another by a recess configured to receive a portion of one of the at least two components; and a support portion having at least one supporting surface portion configured to support a further component (being the other of the at least two components, wherein the contact surface portions and the supporting surface portion are configured to receive the at least two components between them and wherein one or both of the contact surface portions and the supporting surface portion are moveable relative to and towards one another to exert heat and/or pressure on the at least two components located between the contact surface portions and the supporting portion.