Reliability of a stretchable interconnect utilizing terminated, in-plane meandered copper conductor

2013 ◽  
Vol 53 (7) ◽  
pp. 956-963 ◽  
Author(s):  
M. Jablonski ◽  
F. Bossuyt ◽  
J. Vanfleteren ◽  
T. Vervust ◽  
H. de Vries
Keyword(s):  
Copper Conductor ◽  
Stretchable Interconnect

A Low Firing Temperature Copper Conductor for use on an Aluminum Metal Compatible Dielectric in LED Thermal Substrate Applications

2012 ◽  
Vol 2012 (1) ◽  
pp. 001178-001184 ◽  
Author(s):  
Samson Shahbazi ◽  
Steve Grabey ◽  
Ryan Persons
Keyword(s):  
Thick Film ◽  
Firing Temperature ◽  
Copper Foil ◽  
Performance Testing ◽  
Base Layer ◽  
Reliability Testing ◽  
Metal Base ◽  
Copper Base ◽  
Copper Conductor ◽  
Polymer Dielectric

One of the most important contributing factors in the long life of LEDs (Light Emitting Diode) is keeping them cool, i.e., lowering the junction temperature, which can get as high as 150 °C. One way to accomplish this when building a circuit containing many LED packages is to use a thermal substrate. The majority of High Power/High Brightness (HP/HB) LED thermal circuits manufactured today are based on Metal Core Printed Circuit Board (MCPCB) technology. The MCPCB system consists of a copper foil, polymer dielectric layer and either an aluminum or copper base layer that are laminated together. The process of making MCPCB is a subtractive process, where most of the copper foil is removed. The copper foil is etched to create a circuit layer, the polymer dielectric provides the insulation between the copper foil and the metal base, and the aluminum or copper base provides thermal dissipation. The thick film copper paste discussed in this document is processed using an additive process, like screening printing, where the copper conductor is deposited only in the chosen area. The copper thick film paste is screen printed to create a circuit design on top of a thick film dielectric (insulated area) layer which is also printed on a metal base layer. The selective deposition allows for less material usage, and potentially lower overall cost as well as improved thermal performance with inclusion of thermal vias. This paper discusses the results of a newly developed lead (Pb) and cadmium (Cd) free low firing temperature (580–600°C) copper thick film conductor paste on top of a low temperature firing dielectric paste. This study includes evaluations based on SEM photos, solderability, leach resistance, and initial and long term adhesions using SAC 305 solder and RMA flux. There are many different applications for HP/HB LED circuits, from general lighting to street lighting to automotive lighting and more. All of them have varying degrees of performance testing requirement. To try to cover as much of the reliability testing as possible we have included tests such as thermal aging (150°C), thermal cycling from −50 to+150°C, as well as 85°C/85% RH reliability testing under bias.

Experimental Investigation of Fatigue Performance of a 300 mm2 Copper Power Conductor

2013 ◽  
Author(s):  
Fachri P. Nasution ◽  
Svein Sævik ◽  
Stig Berge
Keyword(s):  
Fatigue Strength ◽  
Cross Section ◽  
Fatigue Crack Initiation ◽  
Fatigue Performance ◽  
Power Cables ◽  
Floating Structure ◽  
Copper Conductor ◽  
Sea Bed ◽  
Full Cross Section ◽  
The Waves

Electrical power cables are used in conjunction with floating units for provision of energy to installations on the sea bed, power from land to the floater, or export of power from a wind turbine to land. Power cables that are linked to a floating unit are subjected to fatigue loading from the waves and due to the movement of the vessel in the waves. Fatigue strength needs to be verified for design. Fatigue performance of a 300 mm2 stranded copper conductor was investigated. The experimental work included fatigue tests of individual wires and full cross section conductors including unlubricated and lubricated conductors. Individual wires from different layers were tested in tension-tension mode with stress ratio R = 0.1. Full cross-section conductors were tested in cyclic reversed bending with constant tension at ends, simulating the loading at the top end of a conductor hanging off a floating structure through a bellmouth. The objective of this paper is experimental assessment of the fatigue strength of a 300 mm2 copper conductor and to investigation of the mechanisms of fatigue crack initiation and growth in individual wires. At the time of submission the test program was still in progress, and conclusions are tentative only. An updated paper with complete results will be published at a later stage.

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