Surface Contamination Measurement and Control by Nondestructive Techniques

1985 ◽  
Vol 28 (6) ◽  
pp. 30-32
Author(s):  
Arvind Arora
Keyword(s):  
Electron Emission ◽  
Printed Circuit Boards ◽  
Thickness Measurement ◽  
Circuit Boards ◽  
Limited Data ◽  
Disk Lubricant ◽  
Wafer Processing ◽  
A New Technique ◽  
And Control ◽  
Measurement And Control

This paper presents a new technique to measure thin layer contamination on the surface of a material. The technique uses low wavelength ultraviolet irradiation to generate optically stimulated electron emission, also known as photo electron emission, which can be used to evaluate surface cleanliness or surface chemical state. Limited data is presented to show application of this technique to wafer processing, disk lubricant thickness measurement and quality control of printed circuit boards.

scholarly journals Biodismantling, a Novel Application of Bioleaching in Recycling of Electronic Wastes

Recycling ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 22
Author(s):  
Benjamin Monneron-Enaud ◽  
Oliver Wiche ◽  
Michael Schlömann
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Boards ◽  
Raw Materials ◽  
Iron Sulfate ◽  
Circuit Boards ◽  
Copper Leaching ◽  
Valuable Metals ◽  
A New Technique ◽  
Abiotic Controls ◽  
Processing Steps

Electronic components (EC) from waste electrical and electronic equipment (WEEE) such as resistors, capacitors, diodes and integrated circuits are a subassembly of printed circuit boards (PCB). They contain a variety of economically valuable elements e.g., tantalum, palladium, gold, and rare earth elements. However, until recently there has been no systematic dismantling and recycling of the EC to satisfy the demand for raw materials. A problem connected with the recycling of the EC is the removal of the components (dismantling) in order to recover the elements in later processing steps. The aim of the present study was to develop a new technique of dismantling using bioleaching technology to lower costs and environmental impact. In triplicate batch experiments, used PCBs were treated by bioleaching using an iron-oxidizing mixed culture largely dominated by Acidithiobacillus ferrooxidans strains supplemented with 20 mM ferrous iron sulfate at pH 1.8 and 30 °C for 20 days. Abiotic controls were treated by similar conditions in two different variations: 20 mM of Fe2+ and 15 mM of Fe3+. After 20 days, successful dismantling was obtained in both the bioleaching and the Fe3+ control batch. The control with Fe2+ did not show a significant effect. The bioleaching condition presented a lower rate of dismantling which can partially be explained by a constantly higher redox potential leading to a competition of solder leaching and copper leaching from the printed copper wires. The results showed that biodismantling—dismantling using bioleaching—is possible and can be a new unit operation of the recycling process to maximize the recovery of valuable metals from PCBs.

Applications of In Situ Ellipsometry in RTP Temperature Measurement and Process Control

1991 ◽  
Vol 224 ◽  
Author(s):  
Hisham Z. Massoud ◽  
Ronald K. Sampson ◽  
Kevin A. Conrad ◽  
Yao-Zhi Hu ◽  
Eugene A. Irene
Keyword(s):  
Temperature Dependence ◽  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Index Of Refraction ◽  
Strong Temperature Dependence ◽  
Heating And Cooling ◽  
Wafer Processing ◽  
And Control ◽  
Measurement And Control

AbstractThe applications of in situ automated ellipsometry in the measurement and control of temperature in rapid-thermal processing (RTP) equipment are investigated. This technique relies on the accurate measurement of the index of refraction of a wafer using ellipsometry and the strong temperature dependence of the index of refraction to determine the wafer temperature. In principle, this technique is not limited to silicon wafer processing and could be applied to any surface whose index of refraction has a strong and well known temperature dependence. This technique is non-invasive, non-contact, fast, accurate, compatible with ultraclean processing, and lends itself to monitoring the dynamic heating and cooling cycles encountered in rapid-thermal processing.

scholarly journals Projeto experimental de uma placa de condicionamento de sinal para um sensor de corrente diferencial tipo Bobina de Rogowski

ForScience ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. e00797
Author(s):  
Débora Debiaze de Paula ◽  
Andreyna Sárila Ramos Ferreira ◽  
Paulo Jefferson Dias de Oliveira Evald ◽  
Cláudio Dornelles Mello Júnior ◽  
Rodrigo Zelir Azzolin
Keyword(s):  
Printed Circuit Boards ◽  
Rogowski Coil ◽  
Current Measurement ◽  
Measured Quantity ◽  
Circuit Boards ◽  
Signal Conditioning ◽  
Coil Current ◽  
Experimental Project ◽  
And Control ◽  
Physical Quantities

Realizar a medição de grandezas físicas, tais como corrente e tensão, com precisão é de fundamental importância na área da instrumentação para automação, visto que tais medições geralmente realimentam controladores em malha fechada. De modo geral, os sinais aquisitados são de baixa intensidade. Assim, é indispensável o uso de placas de condicionamento de sinal para converter a grandeza medida em uma forma adequada aos sistemas de processamento de dados e controle. Dessa forma, a principal contribuição deste trabalho é apresentar uma metodologia para elaboração de um sistema de condicionamento de sinais para leitura de corrente, por meio de um sensor do tipo Bobina de Rogowski. Assim, espera-se que, como resultado deste trabalho, qualquer pessoa consiga reproduzir o sistema de medição bem como as placas de circuito impresso apresentadas neste documento para a correta medição de corrente. Além disso, também são apresentados, de forma didática, os passos matemáticos que atendam as especificações do projeto de instrumentação proposto. Palavras-chave: Condicionamento de sinal. Bobina de Rogowski. Medição de corrente. Instrumentação.   Experimental project of a signal conditioning plate for a Rogowski coil differential current sensor Abstract Measurement of physical quantities, such as current and voltage, with precision is of fundamental importance in the area of instrumentation for automation, since such measurements generally feedback closed loop controllers. In general, the signals acquired have low intensity. Thus, it is essential to use signal conditioning plates to convert the measured quantity into a form suitable for data processing and control systems. Thus, the main contribution of this work is to present a methodology for the elaboration of a signal conditioning system for current reading, in a didactic way. It is expected that, as a result of this work, anyone can reproduce the measurement system, as well as the printed circuit boards presented in this document for correct current measurement. In addition, the mathematical steps that meet the specifications of the proposed instrumentation project are also presented in a didactic way. Keywords: Signal conditioning. Rogowski coil. Current measurement. Instrumentation.

Hot Wall Isothermal RTP for Gate Oxide Growth and Nitridation

2000 ◽  
Vol 611 ◽  
Author(s):  
Allan Laser ◽  
Christopher Ratliff ◽  
Jack Yao ◽  
Jeff Bailey ◽  
Jean-Claude Passefort ◽  
...  
Keyword(s):  
Low Cost ◽  
Gate Oxide ◽  
Thermal Systems ◽  
High Quality ◽  
Gate Oxides ◽  
Processing Module ◽  
Wafer Processing ◽  
And Control ◽  
Measurement And Control ◽  
New System

ABSTRACTA new system that incorporates many benefits of large batch furnaces (high quality films, growth of wet and dry oxides, chlorine capability, and low cost) into a single wafer processing module has been developed at SVG Thermal Systems. The problems associated with wafer temperature measurement and control in traditional lamp based RTP systems are avoided by utilizing a hot wall isothermal processing chamber. Unique fixturing is used to minimize thermal stress on the wafer during ramping. High quality gate oxides ranging in thickness from 20Å to 40Å have been grown in this system using both wet and dry oxidation ambients, with and without chlorine. Thin oxides grown in dry oxygen had 1-sigma uniformities in the range of 0.72-0.95%, while oxides grown in oxygen/HCl (1-3%) had uniformities of 0.80%. Steam grown oxides demonstrated growth rates of 100Å/min at 900°C and uniformities of 0.62%. Dry oxides annealed in NO and N2O had peak nitrogen incorporation levels ranging from 0.5 to 5.1 atomic percent depending on anneal ambient, temperature and time.

GMR- AND GMI-BASED SYSTEMS FOR NONDESTRUCTIVE EVALUATION OF PRINTED CIRCUIT BOARD

2007 ◽  
Vol 16 (06) ◽  
pp. 847-857 ◽  
Author(s):  
IBRAHIM ELSHAFIEY ◽  
ASHRAF MOHRA
Keyword(s):  
Nondestructive Evaluation ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
High Sensitivity ◽  
Circuit Board ◽  
Manufacturing Cost ◽  
Circuit Boards ◽  
Printed Circuit ◽  
A New Technique ◽  
Processing Techniques

Advances in magnetoresistive type sensors provide a new technique for nondestructive evaluation of metal structures. Giant magnetoresistive and giant magnetoimpedance sensors provide high sensitivity and reduced size with GMI sensors also adding capabilities of high frequency range of measurements. Being produced with thin film processing techniques, the manufacturing cost of these sensors is low. An example is considered of detecting defects in printed circuit boards. System details and experimental results are provided. Computational modeling validation is introduced based on finite element as well as method of moments analysis.

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