Über die Autorin bzw. den Autor

Octavian Iordache obtained his PhD in chemical engineering from the Polytechnic Institute of Bucharest and a diploma in mathematics from the University of Bucharest. He was a professor of chemical engineering and has conducted research at several universities in Europe and North America. He is with a Montreal-based start up company involved with Research, Development, Test and Evaluation (RDT&E) activities. His research and teaching pertains to the domains of transport phenomena, chemical reaction engineering, material science, stochastic processes and statistics. He has authored 8 books and over 100 papers.

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Developments in science and in technology have led to a dramatic increase in the complexity of industrial systems. Studying, designing, building and controlling such complex systems will be a central challenge for engineers in the coming years. Design of experiments (DOE) is a systematic approach for investigating systems and processes. This book presents a new approach - evolvable design - which is a modern way for replacing pre-programmed and fixed problem-solving methods.
Divided into 5 clear parts, the book begins with an introduction to standard quality methods and the technology in standard electric circuits. The second part looks at evolvable designs of experiments (EDOE) in further detail before providing numerous examples of how to apply the proposed methodology in a series of real-life case studies in the third part. The fourth part is given over to evolvability and relates EDOE methods to evolvable circuits, before summarizing all the methods and applications in a final part. Although these case studies are taken from the printed circuits industry, the methods are equally applicable to other fields of engineering. A valuable reference for system engineering scientists in industry and for electrical and chemical engineers.
Developments in science and in technology have led to a dramatic increase in the complexity of industrial systems. Studying, designing, building and controlling such complex systems will be a central challenge for engineers in the coming years. Design of experiments (DOE) is a systematic approach for investigating systems and processes. This book presents a new approach - evolvable design - which is a modern way for replacing pre-programmed and fixed problem-solving methods.
Divided into 5 clear parts, the book begins with an introduction to standard quality methods and the technology in standard electric circuits. The second part looks at evolvable designs of experiments (EDOE) in further detail before providing numerous examples of how to apply the proposed methodology in a series of real-life case studies in the third part. The fourth part is given over to evolvability and relates EDOE methods to evolvable circuits, before summarizing all the methods and applications in a final part. Although these case studies are taken from the printed circuits industry, the methods are equally applicable to other fields of engineering. A valuable reference for system engineering scientists in industry and for electrical and chemical engineers.

Aus dem Klappentext

Developments in science and in technology have led to a dramatic increase in the complexity of industrial systems. Studying, designing, building and controlling such complex systems will be a central challenge for engineers in the coming years. Design of experiments (DOE) is a systematic approach for investigating systems and processes. This book presents a new approach - evolvable design - which is a modern way for replacing pre-programmed and fixed problem-solving methods.
Divided into 5 clear parts, the book begins with an introduction to standard quality methods and the technology in standard electric circuits. The second part looks at evolvable designs of experiments (EDOE) in further detail before providing numerous examples of how to apply the proposed methodology in a series of real-life case studies in the third part. The fourth part is given over to evolvability and relates EDOE methods to evolvable circuits, before summarizing all the methods and applications in a final part. Although these case studies are taken from the printed circuits industry, the methods are equally applicable to other fields of engineering. A valuable reference for system engineering scientists in industry and for electrical and chemical engineers.
Developments in science and in technology have led to a dramatic increase in the complexity of industrial systems. Studying, designing, building and controlling such complex systems will be a central challenge for engineers in the coming years. Design of experiments (DOE) is a systematic approach for investigating systems and processes. This book presents a new approach - evolvable design - which is a modern way for replacing pre-programmed and fixed problem-solving methods.
Divided into 5 clear parts, the book begins with an introduction to standard quality methods and the technology in standard electric circuits. The second part looks at evolvable designs of experiments (EDOE) in further detail before providing numerous examples of how to apply the proposed methodology in a series of real-life case studies in the third part. The fourth part is given over to evolvability and relates EDOE methods to evolvable circuits, before summarizing all the methods and applications in a final part. Although these case studies are taken from the printed circuits industry, the methods are equally applicable to other fields of engineering. A valuable reference for system engineering scientists in industry and for electrical and chemical engineers.

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Evolvable Designs of Experiments

John Wiley & Sons

Chapter One

1.1 Technology Presentation

Printed circuit boards (PCBs) and printed circuit board assembly (PCBA) case studies serve to illustrate the new design of experiment (DOE) methodology discussed in this book. The PCB is an essential part of the electronic circuit packaging system that interconnects the electronic components for specific tasks. The PCB provides the mechanical support and the necessary connections between the components attached.

The modern PCBs should be smaller, highly integrated, and should have faster operating speed, higher power ranges, and higher reliability.

PCBs are categorized in several ways according to

• Layer count

• Substrate

• Additive or subtractive technology

• Rigidity or flexibility.

According to layer count, the PCBs are classified into three main categories:

• Multilayer PCB

• Double-sided PCB

• Single-sided PCB.

PCBs are also categorized by substrates or base materials into three classes:

• Rigid PCB

• Flexible

• Rigid–flex.

Rigid PCBs are the most common type of PCBs especially when used to interconnect components. Flexible circuits are manufactured on polyimide and polyester substrates that remain flexible at finished thickness. They allow 3D movements. Rigid–flex boards are assembly of rigid and flexible boards laminated together during the manufacturing process.

The most common manufacturing method is based on subtractive processing in which the metal is selectively removed from a PCB, and what remains forms the conductive circuit.

Additive processing refers to a process whereby the circuit is formed by selectively plating metal on a substrate to create a circuit layer. Hybrid methods referred to as partially additive and semiadditive are essentially subtractive methods.

The main constituents of a standard PCB are the copper foil, electroplated on titanium or stainless steel, and the dielectric prepreg, consisting of resin, which may or may not be reinforced with glass fibers, woven or nonwoven, or filaments, or other inert fillers. The prepreg is manufactured by permeating woven glass fabric with a solution of epoxy resin and then passing it through a heat treatment that removes the solvent and partially cures the resin, taking it from the nonreacted stage to the "B-stage," partially cured. Prepreg, that is, "B-stage" with different fabric weaves, different resin systems, and different resin/glass ratios, is accessible. Despite their variety, all the PCBs are basically composed of conductors, dielectrics, and vias. This generic structure determines the few basic steps that are common to most PCB fabrications: materials preparation, inner-layer processing, laminate preparation and lamination, drilling, making conductive holes, imaging, developing, electroplating, etching, solder mask (SM) application, surface finish application, and routing and testing (Coombs, 1996).

1.2 Inner-Layer Processing

In inner-layer processing stage, each layer is processed in a printed circuit structure by resist or film application, imaging, and developing, followed by copper etching and resist stripping. To ensure adhesion between the layers and the additional prepreg layers, all layers are chemically treated by oxidation, to black or red oxide, by application of thin coats of metallic base with bonding properties, such as tin complex compounds or even by the creation of specific topography by inhibited acid treatment.

1.3 Materials Preparation

The core material is sheared to panel size and then cleaned mechanically, chemically, or by combination of both.

Mechanical scrubbing methods include abrasive brush scrubbing and aluminum oxide scrubbing. Brush scrubbing removes a thin layer of surface copper but can produce a surface noncompatible with fine-line circuit design. Aluminum oxide produces a favorable surface for photoresist application.

Chemical cleaning is accomplished in spray chambers with agents such as potassium persulfates. Supplementary steps may include mild oxidizers.

1.4 Lamination

The lamination process involves two distinct yet linked operations:

• Layup

• Lamination.

The layup is referred to as "building up the book." The material is chosen and sized taking into account the expected lifetime of the assembled board.

During the lamination process, the thin-core inner layers are subjected to heat and pressure and compressed into a laminated panel. Prepreg or B-stage sheets are slipped between the layers to bind the layers together.

In this stage, the objective is to form the layup consisting of sheets of copper foil separated by two or more plies of prepreg. This brings the resin to a new stage, sometimes designated as the "C-stage," which corresponds to a more complete cure. The lamination is done under vacuum to remove volatiles as the B-stage cures. The resulting raw board is cleaned and sized.

Sequential lamination is a technology that takes several multilayered circuits and laminates them together to produce one or more multilayered boards. In sequential lamination technology, the panels are drilled and another lamination step takes place for the outer layers. When a design includes different types of vias, it typically requires a set of sequential lamination and electroplating cycles.

1.5 Drilling

The purpose of through-hole drilling PCB is twofold:

• To produce an opening through the board that will permit a subsequent process to form an electrical connection between top, bottom, and internal conductor pathways.

• To permit through the board component mounting with structural integrity and precision of location.

There are critical points to take into account for drilling operation: the alignment between the inner layers and between the inner and outer layers, the drill geometry correlation, speed, and material with smear formation control, the sidewalls integrity, and the removal of residue. The multilayered board may include different types of vias, for instance,

• Through holes

• Buried via

• Blind via.

Buried via is drilled through inner layers and does not exit to either outer layer. Blind via starts at one surface layer but terminates before it penetrates all layers. The blind via is a through hole connecting the surface to one of the internal layers. For some electrical connections, the mechanical drilling was replaced by laser ablation, allowing different sizes of blind via holes in the external layers of the board. Adequate cleaning methods such as mechanical, chemical, or plasma etching follow the drilling. A nonconventional method to make well-defined blind vias in outer layers is to apply the image on the external monomer layer, the photodefinable dielectric that is polymerized by exposure and by blind via emptied as a result of developing. Such materials can be made conductive using specific methods.

The drilling or ablation causes smearing or residues of epoxy resin on the inside of the holes. Aggressive chemicals remove these imperfections.

Hole cleaning refers to a process called desmear and to the closely related process ofetchback. Desmear removes the melted resinsmears that result fromthe frictionof the drill cutting through the...