ESD Systems.com ESD Technical Newsletter - ESD CORNER - January 2000

ESD CORNER

ESD Systems.com ESD Technical Newsletter
Issue 1, January 2000: Volume 3
Reference: http://www.esdsystems.com/newsletters/v3issue1.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

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IN THIS ISSUE:
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· HOT TIP of the MONTH (CDM)

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

· NEPCON WEST (VISIT US)

· ESD Q&A CORNER (Standards)

· PRODUCT UPDATES (Mini Monitor)

· Dr. ZAP (ANSI/ESD S20.20)

HOT TIP of the MONTH (CDM)
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When developing or reviewing your ESD Control Plan, make sure you’ve included the Charge Device Model (CDM) into the program. Most plans only consider the Human Body Model (HBM) and neglect the CDM which can compromise your program. Considerations to anything the ESDS electronic devices come into contact with should be reviewed, such as: packaging; bins; tubes; trays; slides; foam; automated handlers; sorters; etc. Review of the standards may be helpful (ESD STM5.1, ESD DS5.3.1, and ANSI/ESD S20.20)

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/

NEPCON WEST

Visit ESD Systems.com at this years NEPCON West at the Anaheim Convention Center in California this February 29^th – March 2^nd at Booth 5708 which is right at the front door in Hall C.

NEPCON West, Opens the door to a world of innovative solutions and makes it easy to find the products, services and information you need. The world's most important electronic manufacturing event has leading suppliers from around the globe, a world-class conference, exciting special events and more. If you want to be a leader in today's highly competitive global electronics market; you have to be there.

For general questions or comments on about any NEPCON event, please contact Customer Service via e-mail, telephone (800-467-5656), or FAX (203-840-9656). For technical questions or comments on the web site, please send e-mail to the NEPCON Webmaster at webmaster@nepcon.reedexpo.com.

ESD Q&A CORNER
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The following questions and answers were selected from our FAQ WEB Page: http://www.esdsystems.com/question.html concerning Questions about Standards.

Q1: We want to test our floor but do not know the test range it should be in to pass. Can you give me some guide lines for testing our flooring? - Anonymous, Clear Lake, WI

A1: The ESD Association’s standard ANSI/ESD S20.20, (Protection of Electrical and Electronic Parts, Assemblies and Equipment), which references standard ANSI/ESD-S7.1, (Resistive Characterization of Materials - Floor Materials), Item # 36026, recommends that the floor resistance be less than 1x10^9 ohms when tested with an approved megohmeter at 100 volts and with two 5 lb ESD test probes placed 3 feet apart. Our megohmeter, Item # 41273, can test within this range and includes the proper 5 lb probes for testing.

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Q2: What are the guidelines for acceptable resistance range limits for ESD wrist straps/footwear? Are these ranges dependent upon types of devices being worked on? - Anonymous, Skaneateles Falls, NY

A2: The ranges of wrist strap testers (testing a wrist strap systems continuity) according to the ESD S1.1-1998 is less 10 Megohms. For additional operator safety, the industry uses 1 megohm resistors in series with the wrists straps ground path closest to the operator (usually at the snap/buckle interface). Therefore the complete range that we set our units 750 kilohms to 10 Megohms (ESD Systems.com combo tester unit, Item # for is 41201), refer to tech brief #ps-2057 found at - http://www.esdsystems.com/pdf/ps-2057.pdf.

For footwear, this is company dependent, but we factory set our standard footwear testers between 750 kilohms and 100 Megohms. There are variations on the high, e.g., 10 Megohms to 1 gigohm, but is application or internal program dependent.

Summary:

Ranges for testing wrist straps and footwear for ESD control in the semiconductor/electronic assembly is:

750 kilohm < Wrist Strap < 10 megohm
750 kilohm < Foot Wear < 100 megohm

There is movement from the ANSI/ESD S20.20 standard to change this to less then 35 megohm for either wrist straps or a foot wear-flooring system.

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Q3: Which directives for ESD secure products are recommended for the latest & greatest (up to date) approval?
- Is EN100015 the "hottest" norm?
- Can this approval include today’s approvals, is this norm "better"?
- Anonymous, Oslo, Norway

A3: The ESD Association, out of Rome, New York, USA, has taken on a leadership role in defining standards, test methods, standard practices and advisories for ESD control. Most of their standards are ANSI approved as well. They have just revised the MIL-STD-1686 into the standard ANSI/ESD S20.20.

There is a white paper that may help you with more info on ESD Standards located at: http://esdsystems.com/whitepapers/wp_standards.asp

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PRODUCT UPDATES (NEW!)
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Workstation Continuous Mini Monitor - ESD Systems.com Model 41122

real-time monitoring of an ESD workstation and wrist strap

· is a compact unit

· real-time monitoring of an ESD workstation including wrist strap, mat, and cords.

· Red and green LEDs indicate grounding status

· Can be used with any brand of industry standard single-wire wrist straps

· True 100% continuous monitoring, no pulsed current

· cannot be fooled

· There are no false alarms

· no pulsed current that can cause skin irritation

For additional information contact ESD Systems.com at (508) 485-7390, fax (800) 805-5665 or visit our website: http//www.esdsystems.com

Dr. ZAP
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Topic: Differences between ANSI/ESD S20.20 and EIA-625
NOTE: Receive your free copy of this standard from: http://esda.org/pdf_files/s2020std.pdf

Having reviewed the ANSI/ESD S20.20 standard v. the EAI-625. Here are some of the obvious differences:

(Note: If this table is not formatted, please check out our HTML version at: http://www.esdsystems.com/newsletters/v3issue1.htm for your convenience)

ANSI/ESD S20.20 standard v. the EAI-625
Area	EIA-625	S20.20	Notes
Static Generating Sources (Insulators)	£ ±200 volts to be within 12”	³ 2K volts keep at a min. 12”	ESDA performed updated field studies
Auditing frequency	Tables 2 and 3 list item check frequency	6.1.3.1 Compliance Verification Plan Requirement recommends that the frequency of verification checks should be based on the control item usage, its durability and associated risk of failure
Humidity	RH at 40%	30% < RH < 70%
Auditing Body	Requires ESD Coordinator/team for compliance verification	Recommends use of external audits for verification compliance
Work Surface (General)	Recommends dissipative, not conductive	No statement (see notes)	20.20’s Forward, part C, recommends dissipative
Work Surface (specific)	³ 1.0x10⁵ to < 1.0x10⁹ohms	< 1.0x10⁹ ohms (no lower limit)	No lower limit was set to allow stainless steel (cleanroom) worksurfaces to comply even though the worksuface’s committee disagrees
Floor (General)	Table 1 states - needed only when workers are mobile or workstations utilize floor grounding methods.	Section 6.2.2.2 states ESD protective flooring, used with approved footwear, may be used as an alternative to the wrist strap system for standing operations.	625 is a requirement, 20.20 is a recommendation
Floor (specific)	1.0x10⁵ £ to < 1.0x10⁹	< 1.0x10⁹	Suggested lower limit in 625 is for safety
Footwear (General)	Wear two	No statement
Footwear (specific)	2.5x10⁵ £ to £ 1.0x10⁹ohms for 120 volts	< 1.0x10⁹ ohms	UL approves footwear with a minimum resistance of 1x10⁶ ohms
Floor / Footwear System	Not covered	< 3.5x10⁷ ohms or < 100 volts charge generation	First time a standard ties the floor and footwear together
Wrist Strap System	> 2.5x10⁵ to < 1.0x10⁷ ohms for 120 volts	< 3.5x10⁷ ohms	UL approves wrist strap systems with a minimum resistance of 1x10⁶ ohms
Smocks	£ ±200 volts	10⁵ £ to £ 10¹¹ ohms
Ionizers	< ±35 volts balance	< ±50 volts offset voltage	Both reference ANSI EOS/ESD S3.1

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

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