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1 – 10 of 98
Article
Publication date: 1 May 2006

C. Hanumanth Rao, Jissy Varghese, A. Suresh and B.N. Baliga

Realising a solution for effective thermal management for high‐speed electronic packaging for spacecraft applications through dual metal core MLBs.

Abstract

Purpose

Realising a solution for effective thermal management for high‐speed electronic packaging for spacecraft applications through dual metal core MLBs.

Design/methodology/approach

Highlights fabrication issues and describes corrective actions.

Findings

Dual metal core MLBs can solve heat dissipation as well as CTE issues in high‐speed electronic packaging for spacecraft applications. Optimisation of the processes were done to sort out various problems encountered in the fabrication stages.

Originality/value

The paper projects the advantages of dual metal core MLBs over traditional heat sinks and centralized single metal core MLBs. It also helps in simplifying the fabrication processes to avoid the various bottlenecks observed.

Details

Circuit World, vol. 32 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 June 2015

Janusz Sitek, Aneta Araźna, Kamil Janeczek, Wojciech Stęplewski, Krzysztof Lipiec, Konrad Futera and Piotr Ciszewski

– The purpose of this paper is to evaluate the reliability of solder joints made on long FR-4 and metal core printed circuit boards using the accelerated thermal cycling.

Abstract

Purpose

The purpose of this paper is to evaluate the reliability of solder joints made on long FR-4 and metal core printed circuit boards using the accelerated thermal cycling.

Design/methodology/approach

Solder joints of diodes and resistors samples made on long FR-4 and aluminum (Al) core printed circuit boards were examined. Two kinds of solder pastes were used for the samples preparation. All samples were subjected to temperature aging cycles (−40°C – 3 hours/+85°C – 3 hours). Solder joints resistance, X-Ray inspection and metallographic cross-sections for samples as received and after 100, 500 and 1,000 hours of thermal cycles were utilized for solder joints assessment.

Findings

It was stated that 1,000 hours of thermal cycles were enough to show reliability problems in solder joints on long and/or AL core printed circuit board assembly (PCBA). The solder joints of R1206 components were the most sensitive reliability elements. The solder joints of LED diodes are more reliable than solder joints of R1206 resistors. Solder joints made on FR-4 substrate were about two times more reliable than ones on AL core substrate. Cracks in solder joints were the visible reason of solder joints failures.

Originality/value

The influence of thermal cycles on the reliability of solder joints on long, FR-4 and metal core printed circuit boards were presented. Findings from this paper can be used for planning of reliability trials during validation of reflow processes of products containing long or long metal core printed circuit boards (PCBs).

Details

Soldering & Surface Mount Technology, vol. 27 no. 3
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 2 August 2011

Jin Taek Kim, Cheul Ro Lee, Daesuk Kim and Byung Joon Baek

Thermal management under high heat flux is crucial to developing high‐power light‐emitting diode (LED) applications. The purpose of this paper is to propose an efficient thermal…

Abstract

Purpose

Thermal management under high heat flux is crucial to developing high‐power light‐emitting diode (LED) applications. The purpose of this paper is to propose an efficient thermal dissipation technique for an LED back light unit (BLU) system.

Design/methodology/approach

A typical BLU system includes an LED package (GaN on sapphire, cathode/anode, silicone encapsulant, resin plus phosphor) on a printed circuit board (PCB), a light guide panel, and an aluminum cover frame. The temperature distribution of this system has been simulated and the thermal behavior within a 3D model has been investigated using a commercial computational fluid dynamic code (FLUENT 6.3).

Findings

The authors examined the heat‐spreading effect of cover lengths ranging from 6 to 300 mm and also observed the effect of back cover thickness on the junction temperature and cover frame temperature and investigated the influence of the air gap between the package and the cover frame. Removing the air gap lowers the maximum temperature by about 6 percent. It was found that the addition of a copper layer covering the external surfaces of the LED chip enhanced the cooling efficiency. Finally, the maximum junction temperature can be decreased by more than 21 percent in the range of parameters considered by removing the air gap, adding a heat spreader, and using a thick cover frame.

Originality/value

In this paper, thermal management for efficient heat spreading through a typical BLU system without using any additional devices is investigated. Several parameters that increase the system's temperature are examined, and a combination of design features that attenuate the junction temperature is proposed.

Article
Publication date: 6 February 2017

Barbara Dziurdzia and Janusz Mikolajek

The purpose of this paper is to evaluate selected methods of reduction voidings in lead-free solder joints underneath thermal pads of light-emitting diodes (LEDs), using X-ray…

Abstract

Purpose

The purpose of this paper is to evaluate selected methods of reduction voidings in lead-free solder joints underneath thermal pads of light-emitting diodes (LEDs), using X-ray inspection and Six Sigma methodology.

Design/methodology/approach

On the basis of cause and effect diagram for solder voiding, the potential causes of voids and influence of process variables on void formation were found. Three process variables were chosen: the type of reflow soldering, vacuum incorporation and the type of solder paste. Samples of LEDs were mounted with convection and vapour phase reflow soldering. Vacuum was incorporated into vapour phase soldering. Two types of solder pastes OM338PT and LFS-216LT were used. Algorithm incorporated into X-ray inspection system enabled to calculate the statistical distribution of LED thermal pad coverage and to find the process capability index (Cpk) of applied soldering techniques.

Findings

The evaluation of selected soldering processes of LEDs in respect of their thermal pad coverage and statistical Cpk indices is presented. Vapour-phase soldering with vacuum is capable (Cpk > 1) for OM338PT and LFS-216LT paste. Convection reflow without vacuum with LFS-216LT paste is also capable (Cpk = 1.1). Other technological soldering processes require improvements. Vacuum improves radically the capability of a reflow soldering for an LED assembly. When vacuum is not accessible, some improvement of capability to a lower extent is possible by an application of void-free solder pastes.

Originality/value

Six Sigma statistical methodology combined with X-ray diagnosis was used to check whether applied methods of void reduction underneath LED thermal pads are capable processes.

Details

Soldering & Surface Mount Technology, vol. 29 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

Content available
Article
Publication date: 18 April 2008

82

Abstract

Details

Microelectronics International, vol. 25 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 February 1989

M. Forshaw

There is an increasing requirement for inspection of electronic components, assemblies and interconnections, and to meet this demand there are new developments in inspection…

Abstract

There is an increasing requirement for inspection of electronic components, assemblies and interconnections, and to meet this demand there are new developments in inspection techniques. None of the techniques is universally applicable, but many are capable of consistent and reliable results. This paper outlines the major techniques which are available and summarises their capabilities. The limitations on types of component and boards which may be examined are listed, and the difficulties of detecting some flaws with some techniques are highlighted and the reasons considered.

Details

Circuit World, vol. 15 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 October 2018

Fabio Santagata, Jianwen Sun, Elina Iervolino, Hongyu Yu, Fei Wang, Guoqi Zhang, P.M. Sarro and Guoyi Zhang

The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As…

Abstract

Purpose

The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As demonstrators, a smart lighting module and a sensor systems were successfully developed by using the fabrication and assembly process described in this paper.

Design/methodology/approach

The stacked module consists of multiple layers of silicon submounts which can be designed and fabricated in parallel. The 3D stacking design offers higher silicon efficiency and miniaturized package form factor. This platform consists of silicon submount design and fabrication, module packaging, system assembling and testing and analyzing.

Findings

In this paper, a smart light emitting diode system and sensor system will be described based on stacked silicon submount and 3D SiP technology. The integrated smart lighting module meets the optical requirements of general lighting applications. The developed SiP design is also implemented into the miniaturization of particular matter sensors and gas sensor detection system.

Originality/value

SiP has great potential of integrating multiple components into a single compact package, which has potential implementation in intelligent applications.

Details

Microelectronics International, vol. 35 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 April 1982

Francis J. Dance and John L. Wallace

For a full realisation of the packaging advantages of leadless ceramic chip carriers, these devices will be surface mounted on large area printed circuit boards. However, thermal…

Abstract

For a full realisation of the packaging advantages of leadless ceramic chip carriers, these devices will be surface mounted on large area printed circuit boards. However, thermal management and solder joint reliability concerns preclude the usage of conventional board materials and manufacturing processes in most high reliability applications. A new approach for achieving rugged, large area PCBs, incorporating thermal planes and the necessary thermal expansion match to chip carriers is described in this paper. The approach is based upon the use of a clad metal core substrate material fabricated from high conductivity copper and low thermal expansion rate Invar TM, a 36% nickel‐64% iron alloy. Mechanical, electrical and thermal properties of this clad metal are presented as well as techniques for adaption of PCB and porcelain/thick film technologies. Finally, other potential applications for this clad metal in the electronics industry are discussed.

Details

Circuit World, vol. 9 no. 1
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 2013

William Burr, Nick Pearne and Francesca Stern

The purpose of this paper is to a provide short introductory overview of metal in board (MiB) circuit technologies for use in thermal management applications.

Abstract

Purpose

The purpose of this paper is to a provide short introductory overview of metal in board (MiB) circuit technologies for use in thermal management applications.

Design/methodology/approach

The paper details the types of metal in printed circuit boards (PCBs) that are possible and the mix of key features each exhibits. These combinations offer a mix of capabilities in thermal management, current conduction, interconnect density, material usage and cost that can be chosen to suit a specific application. Examples of these board types and their uses are considered.

Findings

Metal core and insulated metal substrate (IMS) PCBs are categories of PCB technologies which provide enhanced thermal management and current carrying capability. MiB technologies are based on conventional printed circuit materials and processes. This gives MiB a range of thermal and current handling characteristics which are particularly suited to a number of key existing and emerging applications.

Research limitations/implications

Further research and development in materials, processes and designs will help broaden the applicability of these types of boards, enabling them to encompass even more thermal management applications.

Originality/value

The paper shows that with 15 different types of metal core and metal backed PCB technologies available to handle thermal dissipation in power electronics, there is one to suit almost every application. This current and emerging portfolio of MiB types offers solutions which can handle thermal loads associated with power densities from about 0.25 W/cm2 to 10‐15 W/cm2 and currents from 20 A up to approximately 1000 A.

Details

Circuit World, vol. 39 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 April 1982

P. Gregory

The evolution of epoxy glass fibre PCBs generally accepted by the industry has not produced major developments in laminate technology. Microminiaturisation of components, improved…

Abstract

The evolution of epoxy glass fibre PCBs generally accepted by the industry has not produced major developments in laminate technology. Microminiaturisation of components, improved packaging of ICs by chip carriers has made apparent that current laminates will be unable to meet interconnection needs and thermal dissipations. This paper discusses the thermal characteristics of alternative systems using metal cored boards and ceramic substrates.

Details

Circuit World, vol. 9 no. 1
Type: Research Article
ISSN: 0305-6120

1 – 10 of 98