Tuesday, August 02, 2005

>> My company would like to implement an ESD program because we handle
>> electronic repair parts for our semiconductor capital equipment.
>> 1. Would you recommend having different levels of protection for
>> components in different HBM classes?
>> 2. We do not manufacture the parts and do not receive any technical spec.
>> sheets to determine which parts are ESD sensitive. How would you
>> recommend we go about determining which type of parts, in our list of
>> thousands of repair parts, are susceptible to ESD damage?
>> Creating a comprehensive list of parts or even types of parts seems
>> daunting, especially without convenient access to the technical
>> specification sheets.

Normally I would not recommend having diferent levels of ESD program unless there were highly different requirements in some areas, for example < 100V HBM parts handled in a specific area.

It can be very difficult to get ESD data. There is some generic information in our on-line ESD Guide .

You can assume that almost any semiconductor device, or pcb containing such a device, is ESD susceptible. The usual approach is to implement an 100V HBM ESD control program which would cover almost everything. However if you handle more sensitive parts, you need to identify these and may need very stringent handling measures.


Duban Michel said...

Usual normalization document IEC 61340 -5-1/2 or ANSI ESD S20.20 are available for ESD sensitive components with sensitivity not less than 100 V in HBM (Human Body Model).
For technology using manual cabling the HBM risk is the most important. For components with ESD HBM sensitivity not less 100 V, the protection by classic method given in normalization documents is absolutely necessary and must be taking in place
However, there are three other ESD risks
CDM (Charge Device Model),
MM (Machine Model)
FIM (Field Induce Model)

These risks are present in all production modes, but in some production mode they become more present and if the person are well grounded, the HBM risk can nearly disappear, and the other degradation modes become the most important.
For example:
In semiconductor elaboration, it seems that the FIM is the most important (Presence of charges and breakdown) on components or masks.
In cabling of dices, the presence of charges and the contact of tool (usually grounded) can give an ESD in CDM.
Coaxial Cable can be charged and if the shielding is not before grounded, when you connect the cable a MM ESD can appear.
If the HBM is relatively well known and information can be obtained from the components manufacturers (we must insist !...) it is not so easy for the other degradation mode but it seems the manufacturers now have more information and can give them.

As Said M. Albert Wallash (an American, very sympatic, ESD Expert) the ESD can be expressed like that:
ESD = Q + M

The ESD risk can be eliminated if one of member of the equation is eliminated or limited.

The technical ESD management can be summarized by:
Charge limitation and ESD protection.

Charge limitation:
Eliminated all insulating materials, grounding all conductive materials, .... use .ionisation (with low off-set).....and so on.....
ESD Protection:
Suppress too conductive materials, Suppress metal contact.

Metal contact is defined, by Albert Wallash as an electrical contact with impedance < 10 K ohm.
The implementation of an ESD program Management can take into account the IEC 61 340 -5-1 /2can be facilitated by two reference documents I like. Both are American documents.
The first one is a very short and easy document:
Protection of Electrical and electronic Parts, assemblies and equipment
In about 10 pages, it gives the basic rules to implement an ESD management program and its limits an data on associated documentation. This document is free of charge on the ESD Association Internet site
The second one is:
ESD Program Management, A realistic Approach to continuous Measurable improvement in static Control, Theodore Dangelmayer.
Ted Dangelmayer was responsible for managing ESD program at Lucent Technologies. now he works as ESD expert and has his Internet site.

michel DUBAN said...

Few months ago, I found a document, D1348, on JPL Internet site.
This document gives the ESD rules for protection of components with a sensitivity of 20 Volts.
As the components become more and more sensitive this document should be very interesting.