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ELECTROSTATIC DISCHARGE (ESD) PROCEDURE Page 1 of 15 QLT842 Rev B Jan 05, 2006 Supersedes : A U:\Doc-Ctrl\Procedur\QLT842B.doc PDPWBS APQP SR&ED Procedure Work Instruction Form No QLT842 201201 Subject: ESD Procedure Purpose: The purpose of this document is to define Flextronics Automotive Inc. standard for Electrostatic Discharge (ESD) control and is written in support of Flextronics Automotive Inc. objective to provide a safe assembly environment using accepted ESD practices Scope: This procedure sets out the minimum requirements for ESD control in Flextronics Automotive Inc. facility covering employees, contractors, visitors and customers. This document applies to activities that: manufacture, process, assemble, install, package, label, service, test, inspect or otherwise handle electrical or electronic parts, assemblies, and equipment susceptible to damage by electrostatic discharges greater than or equal to 100 volts Human Body Model. Responsibility: All Flextronics Automotive Inc. employees. 1.0 Safety Requirements All site safety regulations ARE APPLICABLE during the handling and testing of ESD sensitive parts and shall be observed. Work stations All conductive material must satisfy the electrical requirements of the specific sites Safety and Health manuals* and local electrical codes. Wrist Straps All ESD wrist strap cords must have a built-in one Meg ohm resistor. *Safety requirements, which may pertain to this standard, shall be specified and documented for each site. 2.0 ESD Control Program This document establishes the minimum Electrostatic discharge (ESD) precautionary requirements for handling, any ESD Sensitive (ESDS) assemblies and parts (individually or in bulk) and the associated tools or equipment used in the fabrication or building of these assemblies.

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Page 1: Subject: ESD Procedure - · PDF fileSubject: ESD Procedure ... The ESD audit checklist is the minimum requirement for the ESD control program where applicable. Scoring will be done

ELECTROSTATIC DISCHARGE (ESD)

PROCEDURE

Page 1 of 15

QLT842 Rev B Jan 05, 2006

Supersedes : A

U:\Doc-Ctrl\Procedur\QLT842B.doc

PDPWBS APQP SR&ED Procedure Work Instruction Form

No QLT842 201201

Subject: ESD Procedure

Purpose: The purpose of this document is to define Flextronics Automotive Inc. standard for

Electrostatic Discharge (ESD) control and is written in support of Flextronics Automotive Inc. objective to provide a safe assembly environment using accepted ESD practices

Scope: This procedure sets out the minimum requirements for ESD control in Flextronics Automotive

Inc. facility covering employees, contractors, visitors and customers. This document applies to activities that: manufacture, process, assemble, install, package, label, service, test, inspect or

otherwise handle electrical or electronic parts, assemblies, and equipment susceptible to damage

by electrostatic discharges greater than or equal to 100 volts Human Body Model.

Responsibility: All Flextronics Automotive Inc. employees.

1.0 Safety Requirements

All site safety regulations ARE APPLICABLE during the handling and testing of ESD sensitive parts

and shall be observed. Work stations – All conductive material must satisfy the electrical requirements of the specific sites

Safety and Health manuals* and local electrical codes.

Wrist Straps – All ESD wrist strap cords must have a built-in one Meg ohm resistor.

*Safety requirements, which may pertain to this standard, shall be specified and documented for each site.

2.0 ESD Control Program

This document establishes the minimum Electrostatic discharge (ESD) precautionary requirements for handling, any ESD Sensitive (ESDS) assemblies and parts (individually or in bulk) and the associated

tools or equipment used in the fabrication or building of these assemblies.

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2.0.1 ESD Control Program Requirements

Level of Protection: The intent of this program is to protect all ESDS items, which are sensitive to 100

volts or higher Human Body Model. ESD Devices that are more sensitive may require additional protection. Customer requirements relating to New Products shall consider levels of protection for all

ESDS items as applicable. Program Management and Product Engineering are responsible for

communicating this need to the ESD Coordinator

2.0.2 ESD Control Program Guidance

The primary objective of this Program is to provide continuous ESD protection. Electrostatic control and protection entails implementation of Program requirements during design, production, inspection,

test, storage, shipment, installation, use, maintenance, replacement, and repair functions.

2.1 ESD Control Program Administrative Requirements

2.1.1 ESD Control Program/Policy Guidelines

1. Always wear ESD Smocks and Safety Glasses in the manufacturing area.

2. Always wear ESD shoes/Shoe strap/Wrist strap on the manufacturing floor as designated

3. Daily Verify ESD shoes/Shoe strap/Wrist strap and Sign off against Operation Start up check

list Form #201201 as applicable. 4. Always ensure to be grounded when handlings ESDS devices.

5. Food, Beverages, Lunch boxes, Personal belongings (Purse, Sweaters/jackets, Combs/brushes,

Lotion bottles) strictly prohibited on the manufacturing floor. 6. SMT Magazines, Carts, Shelves, Table Mats and Equipments shall be grounded at all times in

the ESD controlled areas.

7. SMT Magazines shall not be stored on the floor with or with out WIP PCBs. 8. Dragging of Magazines on the floor is strictly prohibited.

9. Manufacturing floor and equipments must be kept clean at all time

10. Doors in ESD controlled areas shall be kept closed at all time for compliance with

HVAC controls. 11. Designated boundaries shall be clearly marked for ESD controlled areas.

12. Personnel and visitors are required as applicable to use wrist strap, heel straps, or conductive

shoes on the manufacturing floor. 13. ESD controlled areas will be measured in regularly scheduled audits by ESD Coordinator.

14. All work surfaces shall be grounded and static dissipative in the ESD controlled areas and their

grounding will be verified against an approved audit

15. Replace used ESD pink foam from black trays with new foam every six month.

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2.1.1.1 ESD Control Program Maintenance

Table 1 summarizes the actions (described in previous sections) that should be scheduled and regularly

performed to maintain an effective ESD control program.

Frequency Action Records (maintain min 90 days)

Daily Check wrist straps, heel straps,

and conductive shoes (see

sections 2.2.2 A & B)

Operation Start up check

list Form #201201

Weekly (or

as

determined by Engr.)

Verify workstation and table

grounding (see section 2.2.6 A)

5S audit

Monthly ESD self-audit (see section

2.1.3.1)

Checklist and written

verification of corrective

action(s)

Clean and test ionizers Preventive maintenance

(PM) log

Perform functional check of

wrist/heel strap testers

Preventive maintenance log

or self-audit checklist/record

Six months Replace used ESD pink foam

from black trays with new foam

Action item in shut down

meetings

Annually Calibrate wrist/footwear tester (see sections 2.2.6 b & C)

Maintain records per site

calibration procedure

Calibrate auditing equipment Maintain records per site

calibration procedure

ESD review training (see section

2.1.2) Attendance records

Course test results, if

applicable

Audit smocks (see section

2.2.2.C)

Log of test results and

corrective actions

Audit by corporate/site

coordinator (3rd

Party Audits)

Checklist and written

verification of corrective

action(s)

Table 1

Site ESD coordinator will be responsible for all ESD related records as outlined in Table 1 or each site

will be responsible for defining the requirements.

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2.1.2 Training Plan

All employees are required to complete ESD training before allowed access to ESD Control Areas. All new

employees are required to complete an ESD orientation before they begin work. It is recommended that all

employees who handle static sensitive parts/assemblies or who work in ESD control areas should receive an ESD control review course once a year. If the ESD compliance score fall below 85% as per the Flextronics

Automotive Inc. audit checklist the site will be required to retrain employees in the affected areas.

ESD non-compliances identified during the audits should be the part of the training process. The training

department or the supervisors will maintain the training record for all employees trained on ESD.

The site ESD Coordinator or his designate shall train and verify the competency of those who deliver

ESD training. Verification of competency shall be undertaken for the following -

a) Amendments to the corporate training material

b) Where the trainer has not been involved in ESD training for a period of 6 months c) Where there are changes in customer ESD requirements

2.1.3 Compliance Verification Plan

Audit activity is to be conducted in accordance with this document and under the general guidance of

the Site ESD Coordinator.

2.1.3.1 Program Coordination

Site ESD Program Coordinator or Quality Manager shall perform audits, and act as a focal point for

ESD problem resolution.

A. Site ESD Coordinator

Each site shall appoint an ESD Program Coordinator who is competent in ESD theory and practice. The ESD coordinator shall be responsible for ESD problem resolution, ESD compliance audits and

consultancy. It is recommended that the Site ESD coordinator audits the system quarterly or ensures that

the ESD system is included as part of the ISO/QS/TS audits.

B. Supervisor Responsibilities

Supervisors are responsible for ensuring that operators are issued the appropriate ESD protective

equipment for their job assignment, and that worn or damaged equipment is promptly replaced. Supervisors are responsible for verifying that all operators are performing the daily ESD wrist and heel

strap tests and for establishing and maintaining Startup check list.

Supervisors who leave an area of responsibility should ensure these records are transferred to the new area supervisor.

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C. Area/Building ESD Representative

Site ESD coordinator could be one group or person. As a minimum, the following audit schedule will be

conducted.

One monthly audit of designated area is to be done using the Flextronics Automotive Inc. ESD checklist; refer to Table 1 for details. Weekly Audits shall consist of a visual inspection of each static

protected work surface and surrounding area for the requirements as stated in this procedure. Audit

results should be logged along with any resulting corrective actions. The audit will be conducted as per Flextronics Automotive Inc. checklist. The ESD audit checklist is the

minimum requirement for the ESD control program where applicable. Scoring will be done as per the

following guidelines:

Score Compliance Level Action

0 No Plan, Procedure or compliance level is <= 80% Initiate Formal Corrective Action

0.5 If compliance is between 80% to 90% Revise Plan, procedure or conduct

awareness training

1 If compliance is >90% None

N/a Where no site specific requirements apply -

D. 3rd

Party Audits Third party audits shall be conducted on an annual basis. The audit will be done to verify ESD

compliance to Flextronics Automotive Inc. procedure and checklist. The results of the audit will be

shared with the Site Operation Manager.

2.2 ESD Control Program Technical Requirements

2.2.1 Grounding / Bonding Systems Guidance Grounding of workstations, carts, storage shelving and personnel is necessary (where applicable) to provide a constant and gradual discharge path for static energy so that it is never

allowed to build to levels that can damage electronics.

Appropriate methods for grounding include but not limited to:

A. 3rd

wire AC (Preferred Method) In most cases, the 3

rd wire AC equipment ground is the preferred ESD ground. When this is

impractical or not available to use, personnel should be bonded or electrically connected to a

conductive element of the ESD item or container using a wrist strap or other grounding system

to ensure that all elements are at the same electrical potential i.e., a wrist strap may be connected to a cart or chassis containing ESD items that are being worked on.

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Electrical power ground should be free of hazardous transient voltages, and regularly tested for continuity to ground. Caution: Connections to the electrical safety ground should only be made

by person knowledge about the power system being accessed.

B. Supporting Pillars

Supporting pillars in the buildings campus could be considered grounded. Any rigid, fixed,

metallic structure (e.g. copper air tubes) could also be considered ground, provided they are

connected to an unpainted section of a supporting pillar in such a way that the connections are reliable and tamper resistant. The pillars should be connected to the earth and regularly tested

for continuity to ground.

C. Copper Wire

The reference for ground could be a solid copper stake at least six feet long and 1/2” diameter

which has been driven into the earth. Brackets should be attached to the top of the stake so that cables can be securely fixed to the stake (see figure 1). Cables should always be connected to

the nearest, best ground source.

Coppergroundingcable

Groundedcoppertubing

Figure 1, Grounding Bracket

Ground reference sources and preferred grounding methods shall be defined and documented

for each site if necessary.

2.2.2 Personal Grounding

The required ESD protection for "ALL" employees is for each to wear an ESD smock together with heel straps/toe straps or ESD footwear (in ESD safe areas). Smocks shall be worn with at

least three of the front snaps closed. Smocks may be worn with sleeves rolled up providing that

the clothes underneath the smock do not protrude beyond the sleeve line and, in the case of

smocks which function through surface conductivity; there is a portion of sleeve in contact with the wearer’s skin. As a general rule, the wearer’s clothes should not be exposed to static

sensitive devices or assemblies.

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The person sponsoring the visitor is responsible for ensuring that they; are provided with all

required ESD protective equipment when the scope of the visit requires access to ESD sensitive

areas, that the visitor has ESD tested and passed the equipment, and that they comply with this procedure while being in a Flextronics Automotive Inc. facility.

A. Wrist Straps

A wrist strap is required for anyone handling ESD components or assemblies while seated,

regardless of heel grounding. (However, personnel exposed to greater than 500V should be considered a special case.) Wrist straps are to be tested at least daily, before handling ESD

sensitive items. Putting approved* lotion on the skin contact site and/or adjusting the strap may

help it to pass. If the strap still fails it must be replaced. After passing, each operator must sign off startup check list as applicable, which must be current and visible.

(*Note: Lotion approved for use in the manufacturing area must be free of silicone and lanolin,

and the bottle should be safe for use within an ESD control area, as appropriate. The local Engineering department and ESD coordinator should verify this.)

B. Heel Straps

Heel straps, or conductive shoes, may be used to ground personnel in areas where there are grounded conductive or dissipative floor mats, or where the floor's resistance to ground

measures between 104 and 109 ohms. The use of heel straps as additional (secondary) grounding devices to help drain static charge generated while walking is encouraged, and may

be required by area management. It is required that the personnel wear one heel strap at all

times – also if wearing ESD safe shoes the personnel does not necessary have to wear the heel strap. ESD shoes must have a visible tag or marking on the outside of the shoe to indicate that

they are ESD shoes

Conductive heel straps and shoes shall be tested before handling ESD items each day. Heel

straps and shoes that fail the test should be cleaned, adjusted, and retested. If the strap/footwear

still fails it must be replaced. After passing, each person must sign off startup check list if

applicable, which must be current and visible.

C. Smocks

Smocks must be worn in all manufacturing areas. They must be audited for effectiveness at least annually, and replaced as needed. Smocks may be checked for effectiveness in one of two

ways: (1) A surface resistivity meter may be used to check that the point to point resistance of

the fabric is within the dissipative range, (2) A charge is applied to the smock (using a charged plate analyzer) and then a field meter or static voltmeter is used to verify that the charge is

dissipated across the seams. ESD smocks shall, as a minimum, cover all personal garments

above the waste in accordance with JEDEC (625-A) requirements.

D. Floor Mats

Grounded, conductive or dissipative floor mats may be necessary in areas approved for

conductive footwear (see section 2.2.2 B). The mats should be cleaned as needed with an approved antistatic cleaner to prevent the buildup of non-conductive particles on the mats.

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2.2.3 Protected Area

A. Signs

Signs should be posted at all entrances to ESD control areas, and the boundaries of these areas

shall be clearly identified. The signs should identify the area as an ESD control area and display the JEDEC (Joint Electronic Device Engineering Council) susceptibility symbol.

Yellow or fluorescent orange-red is the preferred colors for ESD caution signs and labels.

JEDEC susceptibility symbol

Figure 2

B. Floor

The floor shall be kept clean at all time, magazines should not be on the floor with or without PCBs. Dragging the magazines on the floor will damage the floor and it’s resistance to the

ground. The recommended resistance to ground (RTG) of floors in an ESD control area should

be maintained between 104 and 109 ohms (using a 100V test voltage). This condition is mandatory if the floor is used to ground people or carts in the area. Recommended range for

newly installed floors the RTG should be between 104 and 106 ohms. C. Environment Whenever possible, relative humidity in an ESD control area shall be maintained to a minimum

of 30%. If the humidity within the production area falls below 30%, the site ESD Coordinator

shall assess if an increased ESD risk. Where this is considered to be likely, the site ESD Coordinator shall implement whatever measures are considered necessary to mitigate the

increased risk. The temperature shall be between 18C and 27C (64.4 degree Fahrenheit 80.6 degree Fahrenheit).

2.2.4 Packaging

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ESD protective packaging and package marking shall be in accordance with the contract, purchase order, drawing or other documentation. When the contract, purchase order, drawing or

other documentation does not define ESD protective packaging, the Site shall define ESD

protective packaging requirements for ESD items. Some of these types and techniques include low charge generating bags and wraps, air space, dissipative wrap, static shielding, conductive

shunts and the use of EMI/RFI shielding.

Packaging shall be defined for all material movement within Protected Areas, between job sites

and field service operations.

2.2.5 Marking

ESD assemblies and equipment containing ESD parts and assemblies should be marked with an ESD caution symbol as shown in Figure 2.

2.2.6 Equipment

A. Work Stations and Tables

Workstations and tables in an ESD control area must have static dissipative surfaces and should

be connected in parallel. Each workstation must have available wrist strap ground connections (two are recommended), preferably banana jack receptacles. Work surfaces should be cleaned

daily with an antistatic cleaner, and the resistance to ground should be maintained in the static

dissipative range. Surfaces and wrist strap grounding receptacles must be physically wired, in parallel, to the building ground source.

All tables and workstations within an ESD control area shall have the grounding electrically

verified and recorded monthly as determined by the site ESD Coordinator or management specified representative. (See section 2.1.3.1 C) This plan would be documented in the site-

tailoring document. Ground connections should have less than two ohms resistance.

B. Wrist Strap Tester Wrist strap testers or continuous monitors must be used to test the functionality of all wrist

straps. All testers must be calibrated annually. They should be set to accept on readings from

500,000 ohms to 35 Meg ohms resistance. A monthly functional check of each tester is a requirement.

The tester will be checked monthly for functionality the responsibility and authority lies with

the Site ESD coordinator. Please refer to Table 1.

C. Conductive Footwear Tester

Footwear testers must be used to test the functionality of all heel straps and conductive shoes.

All testers must be calibrated annually. They should be set to accept on readings from 500,000 ohms to 35 Meg ohms resistance. A monthly functional check of each tester is a requirement.

The tester will be checked monthly for functionality the responsibility and authority lies with

the Site ESD coordinator. Please refer to Table 1.

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D. Carts and Movable Racks Cart frames should be static dissipative or conductive. In the case of conductive carts, ESD

sensitive materials cannot come in direct contact with the cart. There should be bare metal or

cable connections between the shelves and supports to ensure a path to ground for each shelf. The carts must also be grounded (in areas with dissipative flooring, carts may be grounded by

means of an attached drag chain, or flat, braided cable, with at least two inches of its length in

contact with the floor).

E. Power Tools

Power tools, including soldering irons, need to be grounded (grounding to the local utility is

usually sufficient, but this determination should be made by the site Engineering dept.).

F. Air Ionizers

Air ionizers may be used to reduce the static charge on objects within the process area, which are chargeable to, or generate greater than 100 volts (as determined by Engineering). Ionizers

should be turned on at least 2-3 minutes before unprotected ESD sensitive items are handled

nearby, and should primarily be focused such that the ionized air surrounds the sensitive

devices.

Ionizers shall be cleaned and tested for functionality at least monthly. Air ionizers shall be

tested monthly for positive and negative decay and balance, and adjusted, if necessary, to ensure the final balance is below 30V and the decay times do not exceed 5 seconds each. Ionizers shall

be serialized and test data recorded by serial number. Ionizer test logs should include, at a

minimum: test date, decay time for a positive charge, decay time for a negative charge, final balance, notes of corrective action, and the initials of the person performing the tests. Self-

balancing ionizers, which do not require adjustment according to the manufacturer, need not be

tested monthly. However, should receive maintenance according to the manufacturer's

recommendations.

G. Topical Antistat

Topical antistatic treatment of chargeable objects may be used providing that its effectiveness is checked regularly (the recommended frequency is weekly) and renewed as needed. Caution:

Some topical antistatic chemicals will cause cracking of polycarbonate plastics.

H. Gloves and Finger Cots (Optional) To aid in contamination control and/or to handle hot (high temperature) ESD parts and/or cards,

static safe gloves or finger cots may be required. Their function, when and how they are to be

used shall be specified in the process routings. Note: Although it is desirable to have conductive or static dissipative gloves for static

protection purposes, other issues often force compromises in material selection. Some available

gloves are not conductive, but they do not generate static charges during normal use. Questions regarding various glove compositions should be directed to the Site ESD Coordinator.

I. Storage Bins

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All parts bins and containers used in any manufacturing process must be static dissipative or antistatic. Sensitive parts should remain in the original protective container if practical until

assembled.

J. Shelving and Cabinets

All shelving and cabinets used for storage of ESD components must provide a grounded surface

unless the parts remain fully enclosed within shielding-type packaging such as approved ESD

bags or original manufacturer’s packaging such as SMT reels and IC trays.

2.2.7 Handling

Direct handling of unprotected ESD sensitive (ESD) parts, assemblies, or products, shall only

be by grounded personnel within an ESD control area. Unprotected ESD items should not be

allowed to come in direct contact with grounded, conductive equipment housings or metal surfaces (for example, metal shelves and carts).

To move ESD parts or assemblies inside an ESD control area, use one of the following:

a. Static dissipative containers

b. Static shielding containers c. Conductive containers or board carriers

d. Grounded movable racks (see section 2.2.6 D)

Open containers and board carriers should be transported on grounded carts

A. Transportation

Off-Site: To move components and assemblies off-Site, use only closed static shielding containers (original, closed, vendor packaging is also acceptable). Antistatic packaging (for

example, DIP tubes) alone is not sufficient for this purpose. The containers should also be

labeled as containing static sensitive items.

Between Buildings On Site: To move components and assemblies between buildings (intra-site), use only closed static shielding containers, and ESD safe carts and/or in Faraday cage. (See sec

2.2.6.D). All ESD protection measures must be utilized and items must not be left unattended

while in transit Between ESD Control areas within Building: All ESD protection measures must be utilized and

items may not be left unattended while in transit

B. Static Generating Material All process essential insulators that have electrostatic fields that exceed 2,000 volts should be

kept at a minimum distance of 12 inches from ESD items. If these "static generators" are

essential to the effective operation of processes in the area, steps must be taken to minimize the risk the materials represent (see Table 2). Any signs posted at workstations shall be posted in

anti-static sheet protectors or plain paper. Ordinary plastic sheet protectors or document holders

should be avoided in an ESD safe area and in any case must not come within 12” of unprotected parts or assemblies.

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Methods for Minimizing ESD Risk of Process-Essential Static Generators*

Containment Methods/Options Static Generating Material Example

Remove from control area Excess boxes and packaging material,

Styrofoam

Replace with ESD-safe alternatives Tape, binders, page protectors, plastic bags

and boxes, foam

Apply Ionization (see section 2.2.6 F) Plastic connector packaging, plastic case-with-board assembly (e.g. mouse

assembly)

Separate from ESD items by at least

12 inches

Exterior packing foam (for outgoing

product)

Shield charge from ESD items Computer displays (VDT's)

May treat with topical antistatic Computer keyboards and monitor cases, plastic "windows" or "guards" on

machinery

*Note: A combination of methods may be required. The material types shown are examples;

individual static generators should be evaluated by engineering for the best ESD minimization

method(s) to use.

Table 2

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Records Retained for a period of one year.

Definitions Antistatic Material — material, which resists triboelectric charge generation (i.e. generating static charges by

rubbing or other type of contact). Antistatic materials are not static shielding (see Table 3).

Conductive Material — material with surface resistivity less than 105 ohms per square. Conductive material will

shield an object completely enclosed within it from a charge, will dissipate charges immediately, and must be grounded. Ungrounded conductive materials will accept/generate charge (see Table 3).

Decay Time — the time required to reduce the initial voltage, U1, of a charged material to a defined lower voltage

level, U2.

ESD — electrostatic discharge. A sudden transfer of electrostatic charge between objects at different potentials caused by direct contact or induced by an electrostatic field.

ESD Control Area — any area where unprotected static sensitive parts may be handled (see section 2.1).

ESD Model – Human Body Model (HBM) - Three-circuit models are used to analyze the effects of ESD. They are

“The Human Body Model” (HBM), “The Charged Device Model” (CDM) and “The Machine Model” (MM).

These models help determine the resistive ranges for safe static discharge.

People are a primary source of static charge accumulation. Hair, hair products, types of clothing and type of shoes

worn all affect the way the human body can collect and store a charge. Actions such as walking, sitting, or

handling a product can cause an ungrounded body to develop a significant static charge.

The Human Body Model (HBM) characterizes a static event resulting from a charged person discharging to a static

sensitive device. Typically, the human body senses (hear, see, feel) static discharges at levels above 3500 volts. We hear the POP! We see the SPARK! We feel the JOLT! At levels below 3500 volts, we cannot (through the

use of the body) detect when a static event occurs.

The charge that the human body is able to carry is sufficient to damage an ESD-sensitive component. The

damaging effects of electrostatic discharge are not always immediate and often difficult to detect. A card could be

damaged due to a static event and still pass in-circuit and functional tests! The safest practice to guard against

static discharge from people is personnel grounding.

ESD Sensitive (ESD) — Describes any device or assembly whose electrical characteristics or performance can be

altered by exposure to static electric charge or a discharge through its conductors.

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ELECTROSTATIC DISCHARGE (ESD)

PROCEDURE

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Faraday Cage — a closed conductive container, which provides ESD protection because all external charges are

distributed over its outside surface. No externally caused field is detectable inside a Faraday cage.

Ground — a conductor connected to the earth, and hence, used as a reference point for zero potential (“hard

ground”).

Insulative Material — material with a surface resistivity greater than or equal to 1012 ohms per square. Insulative material accepts/generates charges readily but will not dissipate a charge. The material cannot be grounded and is

not static shielding (see Table 3).

RTG — resistance to ground

Static Dissipative Material — material with a surface resistivity greater than or equal to 105 but less than 1012 ohms

per square; however, the preferred operating definition for non-packaging materials is >105 and <109 ohms per

square. Static dissipative material is not static shielding, will dissipate charges in a controlled manner and must be grounded. Ungrounded static dissipative materials will accept/generate charge (see Table 3).

Static Shielding Material — material with a conductive layer or surface. Containers made of static shielding material should completely enclose their contents and be able to be sealed. When a static shielding container is

closed, the conductive layer in the material forms a Faraday cage that does not allow an ESD or electrostatic field

to pass, penetrate or puncture through the material.

Surface Resistivity — a measure of the resistance of a material to electric current on its surface. It is the ratio of

direct current (dc) voltage to the current that passes across the surface of a material (expressed in ohms per square).

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ELECTROSTATIC DISCHARGE (ESD)

PROCEDURE

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Summary Table of Key Definitions

Conductive

Static

Dissipative

Static

Dissipative

(packaging

materials

only)

Anti-

static

Insulative

Surface resistivity

<105 Ohms/sq

>105 and <109

>105 and <1012

N/A

>1012

Resistance to ground

(RTG)

<105 Ohms/sq

>105 and <109

>105 and <1012

N/A

>1012

Must be grounded yes yes yes N/A N/A

Can't be grounded N/A N/A N/A N/A yes

Accepts/generates

charge

only if ungrounde

d

only if

ungrounded

only if

ungrounded

no yes

Dissipates charge yes,

immediately, if

grounded

yes,

controlled, if

grounded

yes,

controlled, if

grounded

N/A no

Static shielding yes if container

is closed

no no no no

Table 3 Attachments N/A

Ref. Documents ANSI/ESD S20.20-1999 ESD Association Std for the Development of an EDC program-

IPC/JEDEC J-STD-033 Standard for Handling, Packing, Shipping and Use of

Moisture/ Reflow Sensitive Surface Mount Devices.

JEDEC625-A Requirements for Handling Electrostatic-Discharge-Sensitive (ESDS) Devices

GOP 703038 Accessories Parts Management for SMT Lines

GOP 703039 Product Purging Procedure

Revision History:

Description of Change Date ECN# Originator Sign-off

Replaced log sheet with startup check list Jan 05, 2006 E06001 A. Hamid

Initial Release Oct09, 02 2360 A. Hamid