Base Material Consideration for High Speed Printed Circuit Boards

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Over the years,the EU RoHS restriction and lead-free capability is the hottest environmental protection subject. In technology trends,signal integrity performance gets more critical based upon today’s higher signal transmission speed demand in every field of applications such as computer CPU and GPU chipset levels,system operation frequency and a variety of communication bus and cables like PCI express,SATA II and AGP bus for computer systems. Signal communication speed will shift from 1-5 Gbps range up to 5-10Gbps depending on applications. In order to meet lead-free requirements and severe processes conditions with good signal integrity performance,the laminate material will play a more and more critical and sensitive role in the system.
From consumer products to high-end applications,there is a need for certain electrical and thermal performance; it is essential to meet those requirements with cost effectiveness. As a base material supplier,we will hereby discuss material design and factors that influence signal integrity,including epoxy and hardener,resin chemical construction,laminate ply-up construction,amount of resin content,fabric weaving density,moisture pick-up and environment factors etc. for a massive mainstream application and low loss application under the hypothesis of lead-free capability.

Author(s)
Eric Liao
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

A Study of 0201’s and Tombstoning in Lead-Free Systems,Phase II Comparison of Final Finishes and Solder Paste Formulations

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Tombstoning,the phenomena where a chip component stands up on one end during the reflow cycle,is well-documented and understood in tin-lead systems. It is reported to occur more frequently in lead-free systems,and smaller components are at greater risk than larger ones. A comprehensive DOE was undertaken to characterize tombstoning of 0201 components in different metallurgical solder systems. Factors included pad geometry,board finish,stencil geometry,solder paste type,print and placement offsets,and reflow profile and atmosphere. The experiment was divided into two phases; the results of Phase II are analyzed and reviewed in this document.

Author(s)
Paul Neathway,Andrew Butterfield,Quyen Chu,Nick Tokotch,Robert Haddick,Jean-Marc Peallat,Chrys Shea,Prashant Chouta
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Broadband Printing – A Paradigm

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The SMT industry is going through a challenging phase of assembling miniature components,such as micro BGA,0.3mm CSP and 01005 passives onto Printed Circuit Boards (PCB). This effort is primarily driven by the cell phone and other hand held device industries due to consumer demand for smaller devices with more functionality. Other industries,such as those that supply the defense and those in medical electronics,among others,are also expected to start using such miniature components in the near future. Because these miniature components require solder deposits that are significantly smaller per pad than other components that will reside on the same circuit board,such as QFPs,PLCC’s,there arises a challenge in SMT assembly to satisfactorily deposit solder paste for all components on the PCB.
As such,a term has arisen in the industry that has lately been used to describe this “one size fits all” process; that term is “Broadband Printing”. Broadband Printing refers to a robust printing process that provides stable process parameters that can print from the smallest to the largest pad in a single assembly with equally satisfactory results.
This paper presents the analysis from a recent printing study employing a test vehicle that includes components such as 01005s to QFPs. In a recent publication,part of this study was presented focusing on 01005 printing only. This printing process was determined to be suitable for 01005s assembly and also analyzed based on statistical capability. The current paper will present the results from additional detailed analysis to determine if this process has the capability to provide sufficient solder paste deposits for larger components located on the same test board. In the future,the SMT industry may always look towards “Broadband Printing” as an alternative to dual stencil or stepped stencil printing technologies in order to meet the needs of both small and large components.

Author(s)
Arun S. Ramasubramanian,Daryl Santos,Rita Mohanty
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Lean Kitting: A Case Study

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Kitting is the first step in printed circuit board assembly. It is initiated well in advance of actual production start to be able to prepare and deliver the kit on time. Kitting involves gathering of parts needed for a particular assembly from the stockroom and issuing the kit to the manufacturing line at the right time and in the right quantity. This paper discusses kitting,describes ways to eliminate waste in different phases of kitting,and illustrates lean kitting using a case study conducted in a major contract manufacturer site.

Author(s)
Ranko Vujosevic,Larry Hausman-Cohen,Jose A. Ramirez,Srinivasan Venkataraman
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Calculating Total Cost of Ownership in Electronics Manufacturing

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Total cost of ownership is a financial estimate designed to help consumers and enterprise managers assess direct and indirect costs commonly related to software or hardware. It is a form of full cost accounting. However,in the world of electronics manufacturing are there any standardized,generally applicable values and guidelines that apply to the determination of the cost-of-ownership of SMT equipment,or software that manufacturers can refer to in order to make decisions that will carry them through the future?
This presentation takes a comprehensive look at the many factors to be considered when purchasing equipment such as purchase price,value retention,operating costs,output quality,ease-of-use,availability,and real performance. We will also discuss the total costs of ownership directly related to the factory flow of projects and processes and,thus,profitability. We will pay special attention to the extent to which the individual factors are truly relevant for the cost-of-ownership computation.
Based on this analysis,the presentation will cover typical COO examples in various manufacturing environments ranging from high-volume to mid-volume and low-volume environments in low-cost and high-cost countries. The presentation will introduce newly developed COO tools that let you make exact and objective COO computations in the electronics industry.
In particular,the presentation will shine light on the question to what extent placement costs have a significant impact on the overall manufacturing costs. It will also do away with some myths and assumptions around cost-of-ownership in electronics manufacturing.

Author(s)
Robert Alexander Gray
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Design Environment ROI: How Design Teams On a Budget Can Build a Best in Class Design Environment

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Design workflow is the core to your design team?s competitive advantage; it?s the conduit by which you turn your team?s expertise and ideas into manufacturable products. And yet,all engineering teams face the challenge of maximizing their productivity within limited financial resources. How can the less-capitalized teams develop a design workflow that competes with the highly-capitalized teams? Simple: open tools.
In this session,we present business examples from both market research and from direct experience with customers and supply chain partners. From these examples,we quantify the impact of some of the key elements of a design flow based on currently available open tools:
- SDK availability
- User Interface throughput
- All free tools are the same (or are they?)
- Blurring steps in the design phase
- Moving DFM upstream for designers
And also report on areas where open distribution tools may NOT be the right choice:
- High performance signal design
- High end design

Author(s)
Nolan Johnson
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Uniformity of Nickel Plating Thickness in High Aspect Ratio Plated Through Holes

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Nickel plating is often used on PWBs to increase wear resistance and to prevent diffusion between copper and other plated metals. The nickel plating is often present in through holes as well as on the surface,such as when the entire PWB panel is nickel/gold plated or when press fit pins are used for assembly. When the plated through holes are evaluated by microsectioning,it often becomes apparent that the nickel plating is not uniform. It tends to be much thinner in the middle of the hole than on the surface of the board,and may not meet minimum thickness requirements. This paper will evaluate the effect of various plating parameters and chemical additives on through hole plating uniformity. Data will be presented comparing direct current and pulse plating. This paper will also evaluate how the addition of chemical additives to increase throwing power affects the intrinsic stress and grain structure of the nickel. Tests include plating PWBs having through holes of varying diameters and aspect ratios with nickel in thicknesses up to 100 mils. Nickel thickness and uniformity are evaluated both by microsection and X-ray fluorescence measurement techniques.

Author(s)
David M. Lee,Frank I. Collins,Ann E. Dietrich,John T. Folkerts,Walter A. Johnston,Richard J Saunders
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Processing High Density Interconnects: Selecting the Best Option for Via Fill Applications

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With the increased use of High Density Interconnects in printed wiring boards (PWB) there is a critical need for reliable methods to completely fill through hole and blind vias. Complete filling of the vias is often necessary to prevent solution entrapment or failures during thermal cycling. For double sided and multilayer printed wiring boards,complete filling of through holes and blind vias include the use of conductive and non-conductive polymeric ceramic filled paste materials,and the occasional use of liquid photoimageable soldermasks (for partial via filling) For blind vias at n-1,superfilling of the via with copper plating is also gaining acceptance in the market place. In addition,methods to fill buried vias include the use of filling with resin during lamination or the use of the polymeric pastes described above. Blind vias within a sublam can be filled via copper plating as well. The best option depends upon via diameter,via depth,productivity and reliability requirements. In recent years plating of microvias and using ceramic-filled plugging paste for buried vias has gained popularity. The purpose of this paper is to discuss the applications,advantages and disadvantages of each option and offer guidelines for selection of the process that will best suit the needs of the board manufacturer. Applications involving copper electroplating and ceramic plugging pastes will be discussed in detail. We will evaluate thermal stability of the vias using Interconnect Stress Testing (IST).

Author(s)
Michael Carano,Bill Bowerman,Lee Burger
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Development of Micro Drill Bit for Drilling Environment-Friendly PCBs

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Currently environment-friendly PCBs (including lead-free assembly compatible PCB and halogen-free PCB) become popular in PCB industry to meet the requirements of environmental protection. Correspondingly,as a fundamental manufacturing process in PCB fabrication,mechanical drilling has to be innovated. A new type of drill bit is developed to provide solutions for drilling environment-friendly PCBs.
Worldwide PCB and micro drill bit manufacturing industry are briefly reviewed first. Challenges of drilling environment-friendly PCBs are described and the objective of this study is covered. Then key design points including helix angle design,primary face angle design and helix groove shape optimization are presented. The influential mechanism of drill bit key parameters on its rigidity,strength,debris evacuation capability is investigated. Helix angle,helix groove shapes and primary face angle are optimized to ensure sufficient cutting edge strength and excellent wear-resistant capacity. Finally,experiments are conducted to verify the performances of micro drill bit with optimized parameters. Experimental results confirm that a micro drill bit with small helix angle and primary face angle as well as optimized helix groove shape is beneficial to drilling environment-friendly PCBs.

Author(s)
Lianyu Fu,Fan Yang
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008

Tools & Methods for Lean Production Management in EA

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Lean manufacturing is far from a new concept,and many within the Electronics Assembly (EA) industry are already familiar with the principles and concepts behind it. However,in spite of widespread understanding,the percentage that actually “Live Lean” within EA tends to be far less.
If “Lean” offers such a compelling business advantage,one must critically ask why it has not yet been adopted widely and successfully to date in the “Leading Edge” EA industry? Fortunately today,several technologies and tools available to the EA industry offer new possibilities to realize a major impact as never before.
The intention of this conference paper is to examine some of the new developments in Lean Production Management in EA. Included is a brief look into Lean Production Management concepts such as the coordinating the “Value Stream” supplying products according to customer demand. Lean Production Management can be viewed as “real-time execution-based scheduling” and can keep the factory activity in perfect synchronization with minimum effort.
For high-mix EA operations this paper will also introduce “capacity-driven” beside the “inventory-driven” methods whereby supplying processes are triggered to produce the next item needed when capacity becomes available in downstream processes.
An important consideration of Lean Production Management is effective control of material levels and WIP (Work In Process). Using various methods for tracking and control provides the ability to highlight “Hidden” problems,and with visibility – further enables one in continuous improvement of the production system.
This paper considers tools and technologies available to assist in institutionalizing Lean Production Management. A discussion of a case study is included.

Author(s)
Tuan Nguyen,Vern Harrison
Resource Type
Technical Paper
Event
IPC APEX EXPO 2008