ESD CORNER

ESD Systems.com ESD Technical Newsletter
Issue 2, February 2000: Volume 3
Reference:
http://www.esdsystems.com/newsletters/v3issue2.htm

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Sender : ESD Systems.com, 19 Brigham Street, # 9, Marlboro, MA 01752-3170
Phone  : 508-485-7390
Fax      : 508-480-0257
E-mail : editor@esdsystems.com

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This is a free monthly newsletter, which specializes on issues in static control in the semiconductor/electronics workplace.

Need your own copy? Want to subscribe to this Newsletter? All you, or your colleague(s), need to do is simply fill out the subscription form at http://www.esdsystems.com/forms/esdmail.asp Let us know what you think. Tell us what you would like to see in future issues. Want to contribute articles or other related information to our Newsletter? Send your comments or contributions to the editor@esdsystems.com

We will have a new look next issue with color, images in an HTML e-mail format.

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IN THIS ISSUE:
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·        HOT TIP of the MONTH (ANSI/ESD-S20.20)

·        ESDA  NE Chapter's General Meeting (March 8, 2000)

·        ESD Q&A CORNER (Static Electricity)

·        PRODUCT UPDATES (Paddles)

·        Dr. ZAP (Static Electricity)



HOT TIP of the MONTH (CDM)
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 Receive your FREE copy of the new ESD Association’s standard, ANSI/ESD S20.20 from:

http://esda.org/pdf_files/s2020std.pdf,

 

also a Spanish version of this standard is available at:

http://www.esdsystems.com/techinfo/2020SPANISH.htm

 


ESDA  NE Chapter's General Meeting
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Date:    Wednesday, March 8, 2000

Time:   Registration 4:30 PM, Tour 5:00 – 6:30 PM

Location: Desco Industries, 90 Hudson Road, Canton, MA  02021, Ph: (781)821-8370

Topic:  Plant Tour of Desco Industries Canton Facility

Speakers:  Darryl Allen and Mike Malkasian, Floor Care and Bag Product Managers, Complimentary Admission and Refreshments, Your Colleagues are Welcome!

Plant tour includes introduction to ESD Control Floor Care Products and ESD Bags as well as a tour of DII’s Aqueous production and ESD Bag conversion processes.

 
For more information on this General Meeting, contact the
Northeast Chapter of the ESD Association, P.O. Box 394, Wilmington, MA 01887. Phone: 508-485-7390; Fax: 508-480-0257; e-mail: noreast@eosesd.org     Web Site: http://www.esdsystems.com/ne_esd/

 

ESD Q&A CORNER
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The following questions and answers were selected from our FAQ WEB Page: http://www.esdsystems.com/default.asp?PageNo=QANDAINDEX concerning Questions about Standards.

Q1: "Static electricity is NOT a build up of electrons".

As I see it protons & electrons are in balanced numbers in an atom. When charge separation tales place it is usually the electron that is moved from one surface (atom) to another. Using the example of a person walking across a carpeted floor - as they collect electrons they leave behind and equal and opposite charge on the atom that lost the electron but don't the electrons that are collected build up in the recipient? Otherwise how can varying levels of static charges be generated? - Bernard McTernan, Woolhope, UK


A1:
 Refer to: http://www.eskimo.com/~billb/redgreen.html
This article may clear a few things up. It is an imbalance of electrons….just semantics


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Q2:   "Electrons in metals move around and between the mass of atoms.."

Does this mean that on the surfaces the electrons are whizzing round in orbit but underneath the surface they are held in check by the protons? Or does it mean that throughout the metal the electrons are whizzing about but that they are not connected to any particular atom, so they move from end to end at random but always maintaining the balance with protons within any one atom? - Bernard McTernan, Woolhope, UK


A2:  
In general, metal atoms have what’s called a fair amount of valence electrons (an electron that belongs to the outermost shell of an atom) and they tend to be ‘free electrons’ (an electron that is not constrained to remain in a particular atom, and is therefore able to move in matter or in a vacuum when acted on by external electric or magnetic fields) hence making them good conductors. All molecules (grouping of atoms) want to be in a neutral state (electrically balanced). Metal molecules usually share their free electrons to obtain a balanced state.

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Q3:   (In describing antistatic bags) "A conductive (in the dissipative range) ...."

What does this mean? Is it that dissipative is a conductor of such an area that any charge will be conducted and spread across the whole width to the point where it does not pose a threat AND THAT THE CONDUCTOR IS NOT GROUNDED? - Bernard McTernan, Woolhope, UK


A3:   There are two definitions for conductive, In ESD control, conductive refers to the resistance of a material that is less than 1x10^4 ohms and dissipative being greater than 1x10^4 ohms. Conductive also has another definition, the ability to conduct free charges. By this definition, anything that is less than 1x10^11 ohms is considered conductive.

 
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Q4:   How does a static discharge damage a device?

Is it because the voltage discharged can burn out a track in the same way as trying to pass too much current through a fuse will burn it out. The fuse wire is essentially a resistor capable of carrying a certain amount of current (amps x volts) and if it's exceeded the wire heats up and very quickly burns out. Tracks in Integrated Circuits are now as thin as one micron (remember 1 micron is roughly one hundredth the thickness of a piece of copying paper) and so are similarly vulnerable to burn out if the current is too high? - Bernard McTernan, Woolhope, UK

A4:   It is not really a static discharge but an ESD event (an arc or large current pulse between two conductors). It is this large current that does the ESD damage.


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PRODUCT UPDATES (almost NEW!)
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ESD Training Paddles easily generate high static voltages

Ideal for Demonstrating Electrostatic Principles

·         ESD Systems.com’s training paddles are an excellent tool for training employees and demonstrating electrostatic principles.

·         Demonstrations include electric fields, field suppression, ionization, triboelectric generation, grounding, charge storage, capacitance, field induction, and electrical properties for both conductive and insulative materials.

·         This kit includes one acrylic and one aluminum paddle for optimum charge generation, both with insulative handles.

·         The 6” paddles are to be used in conjunction with a static field meter, ionization test kit, or charged plate analyzer.

Item #36080 is ideal for training, and we encourage you to give them a try!  For more information and experiments to perform with the paddles, request Tech Brief PS-2079.

 


Dr. ZAP
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Topic: Static Electricity

First a few good links to reviewing the static electricity phenomena:

What is static electricity?  "Static electricity" appears when two dissimilar materials are placed into intimate contact and then separated. This is a charge separation or an IMBALANCE between quantities of positive and negative particles. During contact electrification, it is usually only the negative electrons, which are moved. As negative particles are pulled away from the positive particles, equal and opposite areas of imbalance are created. In one place, you'll have more protons than electrons, and this spot will have an overall positive charge. Elsewhere you'll have more electrons than protons, for an overall negative charge. "Static electricity" exists whenever there are unequal amounts of positive and negative charged particles present. It doesn't matter whether the region of imbalance is still or is flowing; only the imbalance is important. All solid objects contain vast quantities of positive and negative particles whether the objects are electrified or not. When these quantities are not exactly equal and there is a tiny bit more positive than negative (or vice versa), we say that the object is "electrified" or "charged," and that "static electricity" exists. When the quantities are equal, we say the object is "neutral" or "uncharged." "Charged" and "uncharged" depends on the sum of opposite quantities. Since "static electricity" is actually an imbalance in the quantities of positive and negative, it is wrong to believe that the phenomena has anything to do with lack of motion, with being "static." In fact, "static electricity" can easily be made to move along conductive surfaces. When this happens, it continues to display all it's normal characteristics as it flows, so it does not stop being "static electricity" while it moves along very non-statically! In a high voltage electrical system, the wires can attract lint, raise hair, etc., even though there is a large current in the wires and all the charges are flowing. Last, when any electric circuit is broken and the charges stop flowing, they do not turn into "static electricity" and begin attracting lint, etc. A disconnected wire contains charges, which are not moving; yet, it contains no "static electricity!"

For more information on Static Electricity visit our Web Site at http://www.esdsystems.com or William J. Beaty’s page on electricity http://www.eskimo.com/~billb/ele-edu.html



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If you have any comments, suggestions or feedback about the above table, please send them directly to the editor@esdsystems.com, thanks.


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This is a free monthly newsletter, which specializes on issues in static control in the semiconductor/electronics workplace.

Need your own copy? Want to subscribe to this Newsletter? All you or your colleague(s) need to do is simply fill out the subscription form at
http://www.esdsystems.com/forms/esdmail.asp

This Newsletter is never sent unsolicited. To unsubscribe from this mailing, send an e-mail to ESD_Corner@esdsystems.com and put " UNSUBSCRIBE ESD_Newsletters" in the subject.

Let us know what you think. Tell us what you would like to see in future issues. Want to contribute articles or other related information to our Newsletter? Send your comments to the
editor@esdsystems.com

Copyright © Desco Industries, Inc. 2000

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