Technical Library | 2012-08-23 21:06:35.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. Tetrabromobisphenol-A (TBBPA) is the predominant flame retardant used in rigid FR-4 printed wiring boards (PWB). In this application, the TBBPA is fully reacted into the epoxy res
Technical Library | 2022-03-16 19:48:18.0
Dendrites, Electrochemical Migration (ECM) and parasitic leakage, are usually caused by process related contamination. For example, excess flux, poor handling, extraneous solder, fibers, to name a few. One does not normally relate these fails with environmental causes. However, creep corrosion is a mechanism by which electronic products fail in application, primarily related to sulfur pollution present in the air.1 The sulfur reacts with exposed silver, and to a lesser extent, exposed copper. This paper will explore various aspects of the creep corrosion chemical reaction
Technical Library | 2014-08-19 16:07:15.0
Warpage management consists of planning, measuring, analyzing, sharing, and reacting to data related to the surface shapes of electronics components as they change throughout the reflow assembly process. Leading semiconductor manufacturers have had warpage management systems in place for ten years or more, mainly because microchip package warpage must be understood and compensated for in order to attain high assembly yields. Similarly, newer device architectures such as package-on-package and system-on-a-chip are sensitive to warpage-related assembly issues, and companies involved in the manufacture and assembly of these devices tend to have the most advanced warpage management programs.
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 | 2019-09-19 00:28:48.0
The symbiotic relationship between solder masks and selective finishes is not new. The soldermask application is one of the key considerations to ensure a successful application of a selective finish. The selective finish is the final chemical step of the PCB manufacturing process, this is when the panels are at their most valuable and are unfortunately not re-workable. Imperfections are not tolerated, even if they are wholly cosmetic. Quality issues often manifest themselves in the form of a 'ping pong' conversation between the fabricators, the soldermask suppliers and the selective finish suppliers. Without tangible evidence these discussions are difficult to resolve and the selective finish process is usually regarded as responsible. This paper will focus on the chemical characteristics and use them to predict or identify potential issues before they occur rather than specifically name 'critical' soldermasks. It is also the intention of this paper to address the potential of a soldermask to react to common yield hiking practices like UV bumping and oven curing. It is hoped that this awareness will help fabricators to ensure maximum yields by asking the right questions. 'Critical’ soldermasks impact all selective finishes. In this paper, practical experience using immersion tin will be used to highlight the relationship between 'critical' soldermasks and some of the issues seen in the field. The paper will include a novel approach to identify re-deposited volatiles after the reflow.
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