Technical Library | 2021-11-16 22:17:27.0
Ultrasonics, coupled with an aqueous detergent process that cleans at below 43ºC, may be best suited for fine-pitch SMT screens and stencils. Aqueous detergents clean more effectively than solvents, with little or no environmental impact. Because of the environmental concerns driving today's technology decisions, the once simple decision of selecting a stencil cleaning process is now clouded with different chemicals, different cleaning machines and various types of solder paste, all with specific environmental, health and safety related issues and regulations.
Technical Library | 2009-01-21 23:16:14.0
This paper describes a new approach to drying circuit board assemblies that significantly reduces the cost of ownership of an aqueous cleaning system. Drying performance is increased through a hybrid drying process that reduces energy input, exhaust requirements and sound levels. The combination of high temperature blow-off and convection brings the flexibility to tailor drying performance to fit the product's drying requirements.
Technical Library | 2000-06-21 17:55:59.0
There was once a time when precision cleaning required minimal thought. Just about anything that was dirty could be placed inside a vapor degreaser and emerge clean and dry in a matter of minutes. Today, precision cleaning decisions are seemingly endless with ever-changing environmental regulations, user safety issues and product compatibility concerns. Technologies range from spray-in-atmosphere to ultrasonics to spray under immersion using aqueous, solvent or semiaqueous chemistries. Which method works and with what chemistry? Will the process be safe or even allowed by the regulating agencies?
Technical Library | 2009-09-30 23:12:29.0
Being involved in the electronics assembly industry for more than 23 years, specifically in the field of defluxing and cleanliness testing, I have seen my share of environmental regulations. Long before the debate over lead-free alloys, there was the Montreal Protocol.
Technical Library | 2009-03-19 20:23:54.0
Over the past several years, post-reflow defluxing of circuit assemblies has gained in popularity. Microminiaturization of components and boards, combined with higher expected reliability and increased product liability, have contributed to the prominence of defluxing. Lead-free solder paste - with its higher reflow temperatures and negative effects on flux - increase the likelihood of post-reflow defluxing to increase a product's reliability and aesthetic appearance.
Technical Library | 2009-07-29 16:33:01.0
While the origin of the phrase "may you live in interesting times" is widely disputed, the fact that we indeed live in an interesting time is certainly not. While record bank failures and declines in stock values, only rivaled by the Depression era, wreak havoc on consumer confidence, the economic trickle-down effect translates to reductions in production output and ultimately the consolidation of many industries, including electronic assembly.
Technical Library | 2009-08-19 18:13:59.0
There are several advantages to using a contract assembler. One of which is maintaining the ability to dictate desired results. Therefore, how those results are achieved becomes someone else's concern. When you combine this with the fact that many contract assemblers are not accustomed to saying "no," you become a witness to the birth of innovation.
Technical Library | 2019-07-17 17:56:34.0
The increased demand for electronic devices in recent years has led to an extensive research in the field to meet the requirements of the industry. Electrolytic copper has been an important technology in the fabrication of PCBs and semiconductors. Aqueous sulfuric acid baths are explored for filling or building up with copper structures like blind micro vias (BMV), trenches, through holes (TH), and pillar bumps. As circuit miniaturization continues, developing a process that simultaneously fills vias and plates TH with various sizes and aspect ratios, while minimizing the surface copper thickness is critical. Filling BMV and plating TH at the same time, presents great difficulties for the PCB manufactures. The conventional copper plating processes that provide good via fill and leveling of the deposit tend to worsen the throwing power (TP) of the electroplating bath. TP is defined as the ratio of the deposit copper thickness in the center of the through hole to its thickness at the surface. In this paper an optimization of recently developed innovative, one step acid copper plating technology for filling vias with a minimal surface thickness and plating through holes is presented.
Technical Library | 2016-10-24 15:14:23.0
Biosensors – a new Sensor Type from IST AG What are Biosensors? A biosensor is a device capable of detecting a certain substance or analyte with high specificity. Examples of such analytes are glucose, lactate, glutamine and glutamate. Most biosensors measure the concentration of an analyte in an aqueous solution, usually producing an electrical signal, which is proportional to the analyte’s concentration in its measuring range. An enzymatic biosensor comprises an enzyme, which recognizes and reacts with the target analyte generating a chemical signal, a transducer, which produces a physical signal out of that chemical one, and an electronic amplifier, which conditions and amplifies the signal. Biosensors allow the analysis in complex biological media. The detection of a large number of compounds is of great relevance not only for scientific research but also for process control in the chemical and food industry. It is also indispensable in the health care field for the diagnosis and treatment of diseases and monitoring of illnesses. The pharmaceutical and biotechnology industries greatly desire frequent to continuous analysis of biological media. Such analyses are conducted with the aid of analytical instruments like HPLC systems, which, although robust and reliable, are expensive and have a limited suitability for online operation. For this reason, the acquisition of Jobst Technologies GmbH positions IST AG as a key provider of high-performance and reliable online biosensors.
Technical Library | 2018-05-09 22:15:29.0
Creep corrosion on printed circuit boards (PCBs) is the corrosion of copper metallization and the spreading of the copper corrosion products across the PCB surfaces to the extent that they may electrically short circuit neighboring features on the PCB. The iNEMI technical subcommittee on creep corrosion has developed a flowers-of-sulfur (FOS) based test that is sufficiently well developed for consideration as an industry standard qualification test for creep corrosion. This paper will address the important question of how relative humidity affects creep corrosion. A creep corrosion tendency that is inversely proportional to relative humidity may allow data center administrators to eliminate creep corrosion simply by controlling the relative humidity in the data center,thus, avoiding the high cost of gas-phase filtration of gaseous contamination. The creep corrosion relative humidity dependence will be studied using a modified version of the iNEMI FOS test chamber. The design modification allows the achievement of relative humidity as low as 15% in the presence of the chlorine-releasing bleach aqueous solution. The paper will report on the dependence of creep corrosion on humidity in the 15 to 80% relative humidity range by testing ENIG (gold on electroless nickel), ImAg (immersion silver) and OSP (organic surface preservative) finished PCBs, soldered with organic acid flux.
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