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Article
Publication date: 1 April 1987

A.L.M. Angstenberger

Multilayer boards for high‐speed digital applications are no longer solely substrates for the electrical interconnections needed but play an active role regarding the overall…

Abstract

Multilayer boards for high‐speed digital applications are no longer solely substrates for the electrical interconnections needed but play an active role regarding the overall performance of electronic assemblies. In the general part of this paper all the important parameters regarding achievable impedances and their tolerances are discussed in detail. The second part is concerned with the practical realisation of Microwave Theory on a selected example of a high‐speed MLB.

Details

Circuit World, vol. 14 no. 1
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 1987

A. Angstenberger

Both the need for the introduction of automated optical inspection (AOI) systems in the PCB manufacturing process and the requirements, technically and on economic grounds, placed…

Abstract

Both the need for the introduction of automated optical inspection (AOI) systems in the PCB manufacturing process and the requirements, technically and on economic grounds, placed on such equipment are discussed in detail. Furthermore, emphasis is placed on the description of commonly used AOI concepts. The paper ends with a check list containing the most important questions concerning any system's capabilities.

Details

Circuit World, vol. 13 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 March 1994

A. Angstenberger

The paper describes in detail the basics of manufacturing printed circuits and all relevant interactions with the currently used methods of desmearing. A matrix proposes the…

Abstract

The paper describes in detail the basics of manufacturing printed circuits and all relevant interactions with the currently used methods of desmearing. A matrix proposes the optimal method to choose depending on the given needs of an application. The first part discusses the general layup of printed circuits, the commonly used sequences of manufacturing, different types of construction and, of most importance to the desmear processes, the polymeric nature of widely used laminates. Single processes of the through‐plating sequence, as well as the consequences of desmearing for subsequent assembly operations, are highlighted. An overview of currently used methods of desmearing is given with respect to commonly used process parameters as well as the basics of the relevant chemical reactions. The second part of the paper focuses on selection of the optimal desmear method, depending on the nature of the material for a given application, namely the different polymers utilised in rigid, rigid‐flex and microwave circuits. The paper ends with a survey of practical ways to monitor the process capability of any desmear process.

Details

Circuit World, vol. 20 no. 4
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 January 1994

Morton International Inc. have purchased Hoechst AG's printed circuit materials business including their Ozatec dry film and liquid primary imaging photoresists, Ozatec liquid…

Abstract

Morton International Inc. have purchased Hoechst AG's printed circuit materials business including their Ozatec dry film and liquid primary imaging photoresists, Ozatec liquid photoimageable solder masks and related process equipment. Concurrently, Hoechst and its US subsidiary Hoechst Celanese Corporation purchased Morton's semiconductor photoresist business. Completion of these transactions was effective from 4 August 1993.

Details

Circuit World, vol. 20 no. 2
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 February 1985

A. Angstenberger

Today's and, to a greater extent, tomorrow's technologies in the Printed Circuit Industry need — besides very stringent challenges on quality — a very careful, precise and cost…

Abstract

Today's and, to a greater extent, tomorrow's technologies in the Printed Circuit Industry need — besides very stringent challenges on quality — a very careful, precise and cost effective selection of valuable materials and sophisticated techniques in order to achieve optimal relationships between the costs and benefits of each technology. A survey of materials, their costs, technical requirements and also of alternative methods is given — today's and tomorrow's state‐of‐the‐art.

Details

Circuit World, vol. 11 no. 3
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 March 1986

A. Angstenberger

The general section of the paper discusses in detail the demands of SMD‐Technology on Printed Circuit Boards, namely dimensional, thermal, electrical and chemical requirements on…

Abstract

The general section of the paper discusses in detail the demands of SMD‐Technology on Printed Circuit Boards, namely dimensional, thermal, electrical and chemical requirements on both substrates and finished PCBs, besides characteristic features of the production process and the overall performance of the assembly. The second part is concerned with a survey of materials and methods suitable for the needs of SMT printed circuitry. Emphasis is laid on appropriate substrates, thermal management of assemblies and PCBs for high speed/high frequency applications

Details

Circuit World, vol. 12 no. 4
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 January 1985

This event, organised by the Institute of Metal Finishing, will take place at The Post House Hotel, Leicester, on 20 March 1985. The Conference language will be English and…

Abstract

This event, organised by the Institute of Metal Finishing, will take place at The Post House Hotel, Leicester, on 20 March 1985. The Conference language will be English and details of the technical programme are as follows:

Details

Circuit World, vol. 11 no. 2
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 8 February 2011

Andrew J. Cobley, Lindsay Edgar, Martin Goosey, Rod Kellner and Timothy J. Mason

Previous studies have proven that, under optimised ultrasonic conditions, a range of materials used in electronic manufacturing can be sonochemically surface modified using benign…

Abstract

Purpose

Previous studies have proven that, under optimised ultrasonic conditions, a range of materials used in electronic manufacturing can be sonochemically surface modified using benign solutions at low temperature. The purpose of this paper is to focus on a specific process, namely, the desmearing of through holes in printed circuit boards (PCB). The objective was to determine whether the introduction of low frequency ultrasound (20 kHz) to the “etch” stage of a standard “swell and etch” desmear system could enable reduced temperature processing and the use of less chemistry in the permanganate solution.

Design/methodology/approach

The study was divided into three main stages. In the first “screening” phase, the effect of ultrasound in the etch solution was studied by measuring the weight loss after desmear on a PCB laminate material (Isola 370HR). Factors such as etch temperature and concentration of permanganate (including permanganate‐free) were varied. In stage 2, confirmatory runs were carried out on the most promising conditions from the screening work and through holes in a four‐layer multi‐layer board (MLB) were assessed for smear removal using a scanning electron microscope (SEM). Finally, a four‐layer MLB was desmeared through the most promising ultrasonic process and then metallized at a PCB manufacturer. Thermal shock testing was subsequently carried out and sections from the board assessed for inter‐connection defects (ICDs).

Findings

The initial screening study indicated that, whenever ultrasound was used in the etch stage of the desmear process, significantly higher weight loss was achieved compared to a standard “silent” process. This effect was most pronounced when permanganate was removed from the etch solution and, in this situation, weight loss could be an order of magnitude higher than the silent equivalent. Further testing on through holes suggested that smear‐free inner‐layers could only be guaranteed if permanganate was present in the etch solution but that ultrasound again improved smear removal. Final testing under semi‐production conditions confirmed that, if ultrasound was employed in the etch part of the desmear process, then a reduction in processing temperature from 85°C to 60°C could be achieved and the permanganate concentration halved (65 to 33 g/L) whilst still achieving ICD‐free boards.

Originality/value

The paper indicates the feasibility of using ultrasound to reduce temperatures and chemical concentrations used in the permanganate etch solution, whilst still producing through holes with no ICDs.

Details

Circuit World, vol. 37 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 April 1984

J.D.C. Hemsley, a Director of OMI International Corporation's manufacturing and marketing business in the UK, has been elected President of The Institute of Metal Finishing for a

Abstract

J.D.C. Hemsley, a Director of OMI International Corporation's manufacturing and marketing business in the UK, has been elected President of The Institute of Metal Finishing for a two‐year term commencing July 1984.

Details

Circuit World, vol. 11 no. 1
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 1 April 1987

Lorna Cullen

In this second part of the report on Printed Circuit World Convention IV held at the Tokyo Prince Hotel, Tokyo, from 3–5 June 1987, a general synopsis of the content of the papers…

Abstract

In this second part of the report on Printed Circuit World Convention IV held at the Tokyo Prince Hotel, Tokyo, from 3–5 June 1987, a general synopsis of the content of the papers presented in the eighteen technical sessions will be given. As three sessions were run in parallel throughout the 2½‐day conference, and therefore not all presentations were heard by those reporting on the technical programme, a number of them have been briefly summarised from the Convention Proceedings.

Details

Circuit World, vol. 14 no. 1
Type: Research Article
ISSN: 0305-6120

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