PSN Service Manual for Antistatic Measures
Contents
1. for grounding When not grounded The cabinet and DC output terminal generate an AC voltage Surge destruction may occur because the surge filter in the power supply section does not occur Ground b For a measuring unit Unless specified otherwise connect a ground wire to the ground terminal When not grounded Do not ground the unit if the signaling system is grounded Measure the voltage to ground of the cabinet If the voltage is abnormal contact the person in charge of antistatic measures or the administrator for immediate action BD yround For high insulation type judge with 1 because the resistance cannot be measured 1 Check voltage to ground Limits on soldering iron Use an antistatic soldering iron of a high insulation type in the production process Measuring notes 1 Measure the voltage to ground because a soldering iron may have current leakage at the tip 2 If the tip is not grounded substitute 1 for the continuity check d For a solder absorber Measure a solder absorber in the same way as a soldering iron High insulation type Measure the voltage to ground General type Measure the voltage to ground Measure continuity with the ground Measuring notes High insulation solder absorbers are provided to prevent surge destruction To avoid the risks of surge destruction however check the voltage to ground at the absorbing tip Many solder absorbers are n2. 1 1 8m x 1 8m 280 000 20 m roll Selected jig GEX1002 Im x 1 8m 86 000 10 m roll Selected jig GDD1010 1 010 ST polyester Conductive tape Achilles IC tape 50W mm x 50L m 2 800 1 Conductive shoes Achilles ICM 2100 54 000 pairs case Power cord with three blade sockets Small equipment Continuity plate Stainless steel ground plate for mat 30mm x 100mm 2 500 20 case Ground wire for mat Ground plate with ground wire 4 000 10 case Total yen 33 710 The current service jacket will be used as antistatic clothes
3. storage Transport or store electrostatically sensitive parts under a charge free environment 4 Arrangement of work manuals etc Educate workers and make maintenance rules 2 3 Antistatic Repairing Benches and Scenes of Repairing Work Arranged repairing bench Repairer wearing antistatic working clothes and a wrist strap 3 Antistatic Measures for Service Bench Execute the actions of 3 1 to 3 8 securely to protect the PSN service bench from static electricity 3 1 Outlet Grounding Check See Section 4 Check grounding as explained in Section 4 B6 Be sure to use a power cord with three brade sockets when necessary 3 2 Antistatic Measures for Service Floor See Section 6 Lay a conductive floor mat under the repairing bench and floor for grounding When connecting floor mats lay a copper plate under the mats and seal the joints with conductive tape 3 3 Antistatic Measures for Repairing Bench See Section 5 Lay a conductive mat under the repairing bench and connect one end of the mat to the ground terminal of an outlet for grounding Attach a ground electrode to the conductive layer black side on the back of a conductive mat handled by the WP C For the ground electrode use a T shaped metal bracket available from DIY centers for wood working When securing the metal bracket on the mat use self locking pins for compact attachment Keep conductive mats clean because they become less effective
4. the mats Note The mats should be grounded at 5 m intervals C Using inter mat connection terminals made by Achilles Connection plate with backing Sticking to the low resistance conductive layer of the mat Conductive mat 1 Conductive mat 2 attached Adhesive backing already peeled Already stuck Before mat attachment D Using SUS inter mat connection electrode belt The SUS electrode belt is contacted with the low resistance conductive layer for continuity Low resistance conductive layer of the conductive mat Note Be careful about bad contact It is recommended to use self locking pins for joining E Mat surface joint treatment The mat surface joints are treated with conductive adhesive tape like the connection plates on the back Manufacturer Achilles Product Conductive tape Model ST polyester IC tape Price 2 800 8 Grounding of Measuring Instruments Jigs and Tools Note Unless specified otherwise equipment not grounded with a power cable 3P plug with ground shall be grounded through an added ground wire for physical protection electric shock prevention and prevention of surge destruction If the signaling system is grounded or different instructions are given in specifications this connection is not necessar because it causes an operational fault a For a DC power supply If the power cable has a 2P plug with no ground connect a dedicated ground wire
5. PSN Service Manual for Antistatic Measures Purpose To take measures for preventing electrostatic faults in semiconductor devices Scope Applicable to all PSN service points and local service points outside Japan November 8 2001 Created by ME Technical Support Group Service Support Department Pioneer Service Network Corporation With cooperation from Production Technology Development Section Production Technology Department VII MEC 1 Necessity of Antistatic Measures The electrostatic breakdown voltages of semiconductor devices are as low as shown in the table below Therefore the probability of damaging semiconductor devices by static electricity generated around human bodies or repairing benches is very high This manual summarizes the minimum antistatic measures necessary at the PSN repairing points with examples 1 1 Semiconductor Devices and Electrostatic Breakdown Voltages Breakdown voltage range V VMOS 30 to 1 800 MOS FET 100 to 200 GaAs FET 100 to 300 EPROM Below 100 V JFET 140 to 7 000 SAW 150 to 500 OP AMP 190 to 2 500 CMOS 250 to 3 000 Schottky Diods 300 to 2 500 Film Resistors 300 to 3 000 Bipolar Transistors 380 to 7 000 ECL 500 to 1 500 SCR 680 to 1 000 Schottky TTL 1 000 to 2 500 XM satellite tuner unit Below 10 V Pickup Below 30 V The breakdown electrostatic voltage of an IC depends on the IC type 1 2 Human Actions and Body Charged Potentials Body charged potential kV Walki
6. ased from an electric materials store into the ground 5 Taking Antistatic Measures on Service Bench Antistatic measures of service bench Measuring unit shelves The conductive floor mat Conductive mat installation range should be wide enough to cover the measuring unit shelves conductive mat repairing bench and chair Wall outlet with ground mp Check 100 V between these A terminals with a tester MT floor mat Same grounding as a conductive mat A on e ee es Banana terminal EO ee Conductive mat T shaped bracket available from DIY center Self locking pin No alligator clips Ground wire Hand strap with 1 M resistor 6 Installation of Conductive Mat 6 1 Conductive Mat Grounding Method Grounding helps a conductive mat eliminate a static potential To each mat be sure to attach electrodes and connect ground wires Electrodes should always be attached to the low resistance conductive layer 1 MW on the back of a conductive mat Top side High resistance conductive layer 100 MW max Black side Low resistance conductive layer 1 MW max Back side Ground Note Attachments to the high resistance conductive layer cannot eliminate a static potential effectively because of high resistance 6 2 Interval of Electrode Attachment to Conductive Mat Attach a connection electrode and connect a ground wire every 5 m unless specified otherwise although this depends
7. be put or removed 1 Appearance Self locking pins are added to reduce the contact resistance The ground wire had better be green or black but white here to prevent a catch The self locking pins to reduce the contact resistance are pierced from the back of the conductive mat and caulked 2 Connection The electrodes are ordinary T shaped brackets made by Doit 90 yen Three self locking pins are used for connection To protect the ground wires 1 Adding a vinyl tube Insert a marking tube into the terminal crimping section for convenience 2 Boring holes in the mat and bundling the wires with lock ties 3 Mat Use an electrostatic mat for a table A mat is either for a floor or a table A floor mat is rigid enough to withstand a load but will melt if touched with a soldering iron 4 Notes on use Always check 1 Since a human body changes resistance measure the value with a person seated 2 Resistance judgment criteria Protective resistance may be unnecessary but may be inserted when necessary because even the minimum value is about 500 kQ The maximum value is 100 MQ at present The values are the same as when shoes are used A system analyzer may indicate 100 MQ 3 Continuity failure Use a wrist strap instead 12 Prevention of Charging by Static Eliminator Effective for Charge Elimination in a Narrow Range Permanently polarized resin parts grill cover and other may be char
8. f a textile easily charged with a static potential chemical fiber or other 3 8 Antistatic Area Identify an antistatic area by color taping When entering an antistatic area prevent static electricity by using antistatic working clothes and conductive shoes 4 Grounding and AC Outlet 4 1 AC Outlet Check Before connection to a power outlet check potentials at the measuring points shown below Measuring instrument AC voltmeter multimeter Measuring point 1 Measuring point 3 Measuring point 2 terminal terminal a Three terminal outlet Ground terminal 4 2 Judgment of Measurement Results Vieasuring poston Contents of measurement Measured value and tolerance Power supply voltage check 100 VAC 1 Voltage between the and Tolerance 7 to 5 terminals Power supply voltage polarity and 100 VAC 2 grounding effects Tolerance 7 to 5 Voltage between the and terminals ower supply voltage polarity and g VAC grounding effects Voltage between the and terminals Tolerance 5 V or less Action taken for a result out of tolerance If a measurement result does not satisfy the corresponding tolerance there may be a wiring error or connection failure Take immediate action 4 3 Wall Outlet with No Ground 1 A power distributing board ground line or ferroconcrete building may be used for grounding 2 If 1 is not possible drive several ground bars purch
9. ged more than prescribed To prevent electrostatic problems neutralize the material potentials with a static eliminator Although there are many kinds of static eliminators an AC voltage applied type is recommended Reasons Since ions of both the positive and negative polarities are generated this type can be used for a charged object of any polarity The static elimination performance is high and an optimum one can be selected from many models in the market according to the charged object Ly E Blow position above the object p Em E la e i 12 1 Example of Static Elimination Fixed distance i _ 12 2 Notes on Using Static Eliminator a Be sure to ground the static eliminator Grounding supports static elimination and ensures safety at current leakage from inside where a high voltage is generated b Install the static eliminator at an appropriate effective distance The effective position is for blowing from above c Maintain performance by periodic maintenance Clean the emitter terminal at least once every six months and replace it if worn Clean the filter If the filter becomes dirty the blow rate goes down and the quantity of ion generation decreases Clean the filter at least once a month d Check the ion balance To confirm the effect of static elimination measure the charge voltage of an object first and check that the voltage goes down to near 0 V within several seconds of ion applicat
10. if their surfaces become dirty 3 4 Antistatic Measures for Measuring Instrument and Tools See Section 8 Connect the ground terminal on the back of a measuring unit on the bench to a ground terminal Be sure to use an antistatic soldering iron or solder eliminator of a high insulation type with grounding 3 5 Conductive Container for Parts and Tools See Section 9 Use a metallic container made of stainless steel or other for parts or tools with a conductive mat on the bench 3 6 Arrangement of Bench Keep the repairing bench free of unnecessary things on the works surface Keep plastic vinyl bags and other easily charged objects our of the way 3 7 Static Measures of Human Body 3 7 1 Using conductive shoes Use conductive shoes with conductive mats Keep conductive shoes clean because they become less effective if the soles become dirty 3 7 2 Using a wrist strap Be sure to attach a clip to the ground line securely Always attach a wrist strap to the skin Keep a wrist strap on during work Check a wrist strap for a line cut periodically Internal resistance 1 MW Using a seat mat Compared with a wrist strap an antistatic seat mat is easy to attach and almost as effective However an antistatic seat mat must be made by the user himeself herself See Section _ for how to make it 3 7 3 Repairer s clothes Wear antistatic working clothes for work For repairing do not wear clothes made o
11. ion 13 Measurement of Electrostatic Potential 1 For electrostatic potential measurements the following units are available Manufacturer Shishido Electrostatic Ltd Manufacturer Kasuga Electric Works Ltd Product Electrostatic potential measuring unit Product Digital low potential measuring unit Model Statiron DZ3 Model KSD 0202 Price 80 000 Price 83 300 14 Costs of Antistatic Measures for Service Bench Antistatic measures of service bench The antistatic measures for one bench costs the following Measuring caper Conductive mat Equipment About 34 000 yen Installation None if installed by customer The conductive floor mat installation range should be wide enough to cover the measuring unit shelves conductive mat repairing bench and chair Wall outlet with ground wie Conductive floor mat Same grounding as a conductive mat 1 eenmvan m m Check 100 V pane these i terminate aS with a testik 2 ae sees Conductive mat T shaped bracket available from DIY center No alligator clips Self locking pin Banana terminal Ground wire ODD Hand strap with 1 M resistor Approximate costs of antistatic measures per bench not including installation Purchase price Unit l Unit price Bench floor Expenses Unit of I P i E Mtii eee of bench XponseS purchase SKY 8W 2 0T x 1 820W mm
12. ng on a nylon carpet 2 0 to 2 5 Sneakers Shuffling on a nylon carpet gt 4 5 Sneakers Clothes Rising from a sofa 3 5 to 4 5 Rayon and cotton Taking off an acrylic sweater 4 5 to 5 0 Underwear Acrylic Clothes Rayon and cotton Taking off polyester working clothes 4 0 to 4 5 Folding an acrylic blanket 5 0 to 6 0 A human is a moving object that is charged with a static potential A little action or a friction with an insulator generates static electricity easily A human feels a discharge only if the charge level is within 2 to 3 kV 2 Basics of Antistatic Measures 2 1 Basic Concept of Antistatic Measures 1 No electrostatic generation Minimize the static electricity even if generated 2 No electrostatic charging Ground generated static electricity immediately to prevent retention 3 No electrostatic discharging Do not cause an electrostatic discharge at a specific place 4 Shielding Shield a device to avoid influences from an approaching charged article and generated static electricity 5 1 to 3 are methods of eliminating the causes of electrostatic faults and 4 is a method of guarding devices from electrostatic faults 2 2 Basic Rules of Antistatic Measures 1 Arrangement of working environment Minimize the static electricity even if generated 2 Grounding of human body Discharge a human body for parts sensitive to static electricity 3 Arrangement of containers for transportation or
13. on the mat type E m interval Low resistance conductive layer 6 3 Electrodes and Their Attachments to Conductive Mat a Connection electrode made by 3M Electrode from the top side Electrode from the back side Put the claw through the low resistance conductive layer from the back of the mat and bend it for joining b Connection electrode made by Achilles Double side adhesive tape for attachment Peel off the backing and stick the tape to the low resistance conductive layer c Electrode with general purpose bracket Attach the electrode to the low resistance conductive layer from the back SUS electrode of the mat Attach with a self locking pin for lead wire connection Use a crimp terminal at the tip of the lead wire ee Attach with a self locking pin two or more for mat connection 7 Connections of Conductive Floor Mats Mat to Mat A Using inter mat connection plates made by Achilles In the figure at left three mats are laid Connection method Attach dedicated electrodes to the low resistance conductive layer of mat 1 and connect ground wires Attach dedicated electrodes to the low resistance conductive layer of Mats 2 and 3 and connect ground wires The electrodes shall be attached and connected to ground wires at 5 m intervals B Using inter mat connection terminals made by 3M Connection _ ED Connection terminals are used to set up continuity between
14. ot designed against static electricity When using a solder absorber avoid risks by grounding and inspection to ensure safety A solder absorber with a 2P power cable is not designed against static electricity Secure grounding 9 For Parts Tray or Trash Box Using a metal parts tray Using a metal trash box 10 Antistatic Measures by Conductive Shoes A metal parts tray does not require grounding because it is usually not charged If there is a risk of contacting semiconductor mounted parts however ground the tray Reason The tray functions and stores a potential like a capacitor Grounding will release the potential A metal trash box does not require grounding because it is usually not charged There is no risk of contacting semiconductor mounted parts Even when there are charged things inside the static shielding effect reduces the risk Always use conductive shoes with conductive mats Example 1 Manufacturer Midori Anzen Co Ltd Product Elepath Cool Model No 21001014 Example 2 Manufacturer Achilles Corp Product IC Shoes Model ICM 2100 Male ICL 2101 Female 11 Creation of Antistatic Seat Mat Since a wrist strap is put on or removed according to the work and circumstances a worker may forget to put on a wrist strap when necessary The antistatic seat mat shown below can replace a wrist strap because it is comparatively easy to create has a proven effect and need not
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