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A Complete Solution to Microvia Metallization
The article describes the advantages using of a conductive polymer to metallize high density microvias and discusses the development and optimization of a vertical electrolytic copper process for both microvia filling and through-hole mellization of HDI boards. The combination of the two processes provides a complete solution by enabling the highest yields of microvia metallization and the lowest assembly solder joint voids for via-in-pad technologies.
From Printed Circuit Design & Manufacture, February 2007
A Solution to Reducing the Cost of Acid Zinc Plating
The article provides the results of a controlled test at a production plant, along with three case histories. Each clearly demonstrates the superiority of an innovative acid zinc chloride process (ENTHOBRITE CLZ-970) compared with a conventional zinc chloride process. In each case, ENTHOBRITE CLZ-970 was proven to achieve a significant reduction in metal usage of at least 20%, without compromising the OEM's zinc thickness requirements. Furthermore, production efficiency was achieved by a reduction in total plating time and/or an increase in capacity.
A Study of Planar Microvoiding in Pb-free Solder Joints
The DOE study conducted by a major OEM clearly demonstrates that the AlphaSTAR® immersion silver process is intrinsically resistant to cave and microvoid formation, while capable of overcoming copper surface variations.
From IPC Expo / APEX 2007 Technical Conference Proceedings
Chromium Rules: A Finishing Industry Challenge
Much has been written on regulations pertaining to chromium. The average person is often left a bit overwhelmed with lists, acronyms, acceptable levels, ad infinitum. We will attempt to summarize these regulations and offer opinions and insight on their potential affect on the metal finishing industry.
From Job Shop Technology.
Elimination of Immersion Silver Plating Defects
Based on the JPCA award-winning Enthone technical paper, "Root Cause Analysis and Elimination of Immersion Silver Plating Defects on PWBs through Process Optimization," the article details the "Ideal Process" versus other leading traditional silver processes. The article provides the results of a twelve-month survey conducted among some of the world’s leading users of immersion silver plating technology. The survey identifies six major technical reasons (“root causes”) for board failure or rejection, including: microvoids, galvanic attack, tarnishing, exposed copper, ionic contamination and poor solderability.Preventative measures to minimize or eliminate each of the six failure modes are provided
From CircuiTree, November 2006
End of the Road for Hexavalent Chromium
The article details new hex-chrome free coatings that enable automotive manufacturers to deliver environmentally sound products without sacrificing performance, quality, cost or safety. Such hex-chrome-free systems consisting of zinc and zinc alloys , specially formulated conversion coatings and topcoats, enable OEMs the ability to provide high performance products that meet the End of Life (ELV) Directive to minimize or eliminate hazardous substances. Authored by Linda Wing, Enthone Automotive Industry Manager
Automotive Engineering International, June 2004
ENPLATE Electroless Nickel
ENPLATE electroless nickels are chemical plating processes that autocatalytically deposit nickel alloyed with up to 12% by weight phosphorus.
ENPLATE Electroless Nickel Plating Process for Rigid Memory Disks
Most plating failures are the result of improper surface cleaning and/or activation. Successful plating is achieved when surface conditioning is given the same consideration as the electroless nickel process.
ENPLATE High Phosphorus Electroless Nickel
High phosphorus content (>10% by weight) ENPLATE electroless nickels are being used in a wide range of industrial applications because of the superior corrosion protection afforded by these coatings.
ENPLATE Nickel/PTFE
ENPLATE electroless nickel/Teflon coatings are a composite of electroless nickel phosphorus and polytetra-fluoroethylene (PTFE).
ENTHOX Conversion Coatings
Conversion coatings available from are a cost-effective method for enhancing the corrosion resistance of plated metal surfaces. They are particularly effective in preventing the formation of white corrosion products on the plated metal. Conversion coatings also are used successfully under paint to improve corrosion resistance. Processes are available for a broad range of industrial and automotive applications.
Environmental Challenges to Conventional PTH Metallization: A Time for Change?
The inability of PWB fabricators to meet the rapidly tightening global regulations will limit the expansion of plating facilities, the permitting of new facilities and will challenge the broader supply capacity. Despite this mounting pressure, the performance and reliability of the copper metallization system is even more critical, especially for the newer electronic devices sweeping the industry. So is there a conflict in these demands? Are there alternative green choices which will not only meet the OEM and EMS supply needs, but which will provide better performance and enable higher capability for the industry?
Presented at the HKPCA 2008 Technical Conference
Extending the Operating Life of Electroless Nickel by Chemical Means
Authored by Helmut Horsthemke and Stanley Zabrocky, the article details a revolutionary long life, high phosphorus electroless nickel technology. The article describes how the sulfur-free, pH self-regulating electroless nickel maintains internal compressive stress through 20 metal turnovers (MTO), while providing consistent deposit properties over an extended operating life without the use of expensive electrodialysis equipment, costly steady state operation (bleed and feed) or expensive chemical alternatives (e.g. nickel hypophosphite).
Metal Finishing, October 2004
Lead-free Solder Bumping and Its Challenges
The Electronics Industry is moving from tin-lead solders to lead-free solders. This movement impacts the following materials areas: soldering material, board finish and component finishes. Solder wafer bumping can be found under component finishes in the semiconductor packaging/flip chip application area. Historically, wafer bumping uses tin/lead solders regardless whether the solder balls are deposited by vapor phase, by stencil printing, by solder paste placement or by electroplating. What is of interest here is wafer bumping by electroplating, which is a relatively low cost alternative especially for fine pitch applications where other technologies face severe limitations. This paper focuses on a number of lead-free bump plating processes that are suitable to replace eutectic tin/lead bumping process. The technical challenges for developing such plating processes that are compatible with existing and n! ew photoresists are discussed. Materials properties as well as reliability characterizations of lead-free solder bumps are also presented. Enthone authors: I. S. Zavarine, Yun Zhang, J. Abys, et alia.
International Wafer Level Packaging Congress, October 2004, San Jose
Making Pulse Plating Work for PCB Metallization
The article details and electrolytic copper process for pulse plating reverse (PPR) applications. Specifically, the article describes waveform distortion, charging and discharging of the electric double layer, pulsating diffusion layer, micro- versus macro-profile and technology possibilities to be explored as the miniaturization of through-hole and microvia progresses. CircuiTree, September 2004.
Multifunctional Coatings in the Automotive Finishing Industry
New trends in finishing systems for automotive applications.
From Metal Finishing.
New, Highest Reliable Generation of PWB Surface Finishes for Lead-free Soldering and Future Applications
The paper details the next generation of OSP (ENTEK PLUS HT) and immersion silver (AlphaSTAR) technologies. OSPs and immersion silver provide lead-free, highly solderable, flat, coplanar surfaces that provide significant improvement in first-pass assembly yields versus HASL and other final finish alternatives. The paper clearly differentiates the benefits of using each finish based on assembly requirements and PWB design.EIPC Summer Conference, Stockholm, Sweden. June 2005.
Novel OSP Coatings for Lead-free Processes
The paper details Gas Chromatography-Mass Spectrum (GC/MS), Thermogravimetric Analysis (TGA), and X-ray Photoelectron Spectroscopy (XPS) results used to characterize the relative thermal properties of a novel high temperature (HT) resistant OSP coating (ENTEK PLUS HT).
From CircuiTree, March 2006
Oxide Replacement for High Temperature Application
The article,discusses the development of a new oxide replacement process specially engineered for high temperature, lead-free PWB assembly applications.
Based on statistically designed experiments, the article details how the new oxide replacement technology delivers a more resilient copper conversion coating versus standard oxide alternatives. This has shown improved bonding performance and greater stability at higher temperatures, thus improving its capability to meet more thermal excursions, e.g. assembly reflow cycles at >260°C, without failure. The article focuses on the development criteria and performance evaluation including data on peel strength, solder float and IR-reflow testing. Benchmarking is described against two standard oxide replacement products.
From Printed Circuit Design & Manufacture, May 2007
Palladium-free Direct Plate Technology for Plating on Plastics
The article details a method to electroplate directly onto non-conductive plastics. The revolutionary Enthone technology does not use precious metals to activate or electroless chemistries to produce the first conductive metallic layer. Instead, this process allows electrolytic nickel to plate directly onto the plastic substrate. This direct plate technology decreases the number of process steps, significantly reduces water consumption, eliminates chelates, and improves productivity.
Products Finishing, September 2005.
Palladium-free Direct Plate Technology for Plating on Plastics without Electroless Chemistries
Plating on plastics has traditionally been accomplished by use of tin/palladium colloidal-type activation systems with electroless chemistries. Although well understood, these processes can be costly and require extended process lines with high water consumption. This paper details a method to electroplate directly onto non-conductive plastics. This revolutionary technology does not use precious metals to activate or electroless chemistries to produce the first conductive metallic layer. Instead, this process allows electrolytic nickel to plate directly onto the plastic substrate. This direct plate technology decreases the number of process steps, significantly reduces water consumption, eliminates chelates, and improves productivity. Authored by Andreas Königshofen, Peter Pies and Brian Griffith.
SUR/FIN Conference, June 2004
Performance characteristics of conductive coatings for EMI control (PDF)
Conductive coatings can be compared in terms of shielding effectiveness when exposed to environmental tests, including thermal shock, temperature and humidity, and salt spray.
Peroxy-Sulfuric Oxide Replacements: A Pathway to Improved Technology for Fine Line Processes
Traditional reduced black oxide processes for inner layer bonding have been superseded by a newer generation of peroxide-sulfuric texturing processes. These lower cost processes, based on an organically controlled micro-etch, have proven to be simpler, faster, and more energy efficient. They have eliminated traditional problems such as: re-oxidation caused by baking and storage; high resistance shorts, and pink ring defects. However, the relentless trend of miniaturization and the inexorable pressures for cost reduction continue to push the envelope. Lower etch factors are necessary for controlled impedance and fine line applications, together with higher copper loadings for increased capacity. The paper describes the major challenges faced, and the resulting technical progression which has been achieved, to evolve the next generation of high performance process capable or meeting this target.
IPC Expo/APEX 2004 Technical Conference, Anaheim, CA
Plating Aluminum Wheels
Dayton Alloy Wheel combines electroless nickel with a decorative finish for corrosion resistance and good looks.
From Products Finishing.
Production Experience and Performance Characteristics of a Novel Immersion Silver
The paper presents the production experience of a novel immersion silver process (AlphaSTAR) in typical horizontal lines to demonstrate its robustness. In addition, several reliability issues known to common immersion silver process are discussed; including galvanic attack, solder joint strength and BGA solder joint integrity.
From IPC Expo/APEX Technical Conference, February 2006
PWB Creeping Corrosion Mechanism and Mitigation Strategy
Immersion Silver is being used widely for a broad variety of PWB applications. The introduction of electronics into increasingly harsh environments, in both the industrial and consumer arenas, has led to the relatively recent discovery of a corrosion phenomenon induced by exposure to humid, sulfur-bearing atmospheres. Referred to as Creeping Corrosion, this phenomenon is characterized by growth of copper sulfide crystals from copper features on the outer surfaces of the PWB. The paper details a special test method to reproduce Creeping Corrosion. DOE results from process experiments utilizing certain PWB fabrication approaches, and potential improvements for the mitigation of Creeping Corrosion are discussed.
SMTA International Conference, 2008
Replacements for Cadmium
Electroplated cadmium has for many decades played an important role as functional coating in many branches of industry and is particularly known as corrosion resistant finish for steel. However, the high degree of toxicity of cadmium metal and its compounds and the consequent danger to the environment have recently forced users to look for alternative coatings where ever possible.
Root Cause Analysis and Elimination of Immersion Silver Plating Defects on PWBs Through Process Optimization
The paper presents the results of a twelve-month survey conducted among some of the leading Asia users of immersion silver plating technology. With the critical need for low ppm defect capability on advanced high-density interconnection applications, this study focused on the most prevalent reasons for failure or rejection of a silver finish, including microvoids and galvanic attack.
From JPCA Show, May 2006
Selecting the Right Final Finish for RoHS Compliant PCBs
The article provides an overview of hot air solder leveling (HASL) final finish alternatives. Each alternative is differentiated by matching each coating's benefits to the specific assembly requirements and PWB design. The article positions immersion silver and high temperature OSPs as the leading, lead-free final finish alternatives. The author's demonstrate how both processes meet the manufacturer's goals for low cost and ease of use, as well as the assemblers demand for high first-pass yields and long term reliability in lead-free assembly.
Printed Circuit Design & Manufacture, March 2007
The Chemistry and Properties of a Newly Developed Immersion Silver Coating for PWB
To meet the emerging requirement of eliminating lead from electronics, the printed wiring board (PWB) industry is migrating from hot-air-leveled PbSn solder to alternative final finishes. A thin layer (2-3 microinches) of silver coating on copper has proven to be able to preserve PWB solderability for up to one year prior to assembly, and to withstand the higher temperature excursions encountered when using lead-free solders. As the demand for a thicker silver coating arises for certain applications with requirements beyond solderability, there is a need for an improved process that is capable of a wide range of coating thickness. This paper describes a new immersion silver process and the resulting coating properties in tarnish resistance, solderability, surface insulation resistance and electromigration resistance. Authored by Enthone: Yung-Herng Yau, Chonglun Fan, Chen Xu, Anthony Fiore, Karl Wengenroth and Joe Abys
IPC Expo/APEX 2004 Technical Conference, Anaheim, CA
The Effect of Via-in-pad Via-fill on Solder Joint Void Formation
E. Stafstrom, A. Singer, G. Echeverria, P.Chouta and J. McLenaghan. As components get smaller the only way to connect pads is through microvias (through layer connections) about 4 thousandths of an inch across....and if the vias are not formed correctly air or contaminants can "burp" into the solder joint and weaken it. A copper microvia fill process is detailed that reduces such bubbles (voids) to provide enhance solder joints and solderability. Awarded "Best Paper," at the 2003 IPC Annual Meeting (Minneapolis, MN).
Tin Whisker Growth – Substrate Effect Understanding CTE Mismatch and IMC Formation
Cookson Electronics received the 2004 Best Domestic Paper Award from the IPC Expo/APEX/Designers Summit Technical Program Committee for this
The paper was co-authored by Dr. Yun Zhang, Dr. Chonglun Fan, Dr. Chen Xu, Dr. Oscar Khaselev and Dr. Joseph Abys of Enthone. The paper discusses the relative contribution of stress generated from IMC and from CTE mismatch on various leadframe and connector substrates at both isothermal and temperature cycling conditions.
IPC Expo/APEX 2004 Technical Conference, Anaheim, CA