ESD aversion Individuals flooring so as to establish framework and conductive shoes The foundation of Material science .


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ESD aversion People flooring so as to establish framework and conductive shoes The foundation of Physics ….. Electrostatic Measurement 13 - th November 2001 ……. The spot of ESD at Workshop. 1 - 60 to 70 % of electronic parts disappointments are because of ElectroStatic Discharges (ESD).
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Slide 1

ESD anticipation People establishing by Flooring framework and conductive shoes The organization of Physics … .. Electrostatic Measurement 13 - th November 2001 … ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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The spot of ESD at Workshop 1 - 60 to 70 % of electronic parts disappointments are because of ElectroStatic Discharges (ESD). 2 – In 1991 HP said : 90 % of ESD disappointments are dormant ones . An inactive disappointment does not give a prompt disappointment but rather entrain a disappointment later, a couple days or a few months later.  This sort of disappointment influence straightforwardly the unwavering quality of electronic supplies. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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ESD Cost Many information are accessible from a few sources.  Hewlett Packard, toward the end of 80 th, assessed the addition proportional to 50 000 PC the principal year taking after the setting up of an ESD control program. Assessed cost given for year 1993 at world level:       8 % of hardware business sector (about FFR 45 milliards (GBP ~ 5 billions). My own experience (15 years with ESD security): -         About 10 ESD blames formally distinguished Cost from GBP 100 to GBP 100, 000 One case: During capability of new ASIC parts   20 segments fizzled, cost ~ GBP 15,000. In any case, ESD disappointments, are hard to distinguished !… . ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Different ESD models (RD 1) 1 - Human body Model : HBM,  2 - Machine Model : MM, 3 - Charged Devices Model : CDM,  4 - Field Induce Model : FIM , 5 - Charged Chip Model : CCM . The ESD Model requirements rely on upon procedure utilized. An essential rule:  No charge, no release . ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Components class 0 limits In an Electro Static Discharge control arrange, the affectability of segments to be taken care of, must be outstanding. The guidelines and practices must consider the affectability of segments and the procedures utilized. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Handle Components/types of gear class 0. Treatment of class 0 parts or types of gear include utilizing each conceivable techniques to battle against the nearness of electrostatic charges: Grounding the individual\'s body, (wrist-strap, conductive shoes on dissipative floor); Personal hardware (coveralls, wrist-strap and its controller, conductive gloves,… Grounding materials or types of gear (working surface , iron… ), Shielding, Packaging (antistatic, conductive), Ionization, People preparing, Audit… .. Electricity produced via friction MUST BE UNDER CONTROL No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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How to dispense with Electrostatic Charges? Conductors materials : Connect them to ground in appreciation of security standards, a man is a conductor as well, he should be associated with ground.  Insulating materials : Eliminate all protecting materials which are redundant in nature of the working surface. Get alternate conductors, with antistat for occurrence and associate them to ground. Disposal of parasitic electrostatic fields . Use, ionization frameworks, dissipative garnements, gloves… No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Standardization Procedure The guidelines, strategy and breaking points to dispense with the ESD danger are given in standard archives: IEC 61340 5 - 1 (RD2), IEC 61340 - 5-2 (RD3 ) . 1 - Methods: Elimination of electrostatic charges on individual : . People can be grounded by antistatic wrist-strap or by dissipative deck framework with conductive shoes, it depends of individuals action. No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Standardization Procedure 2 - Limits   Depend on parts affectability,   Most touchy segments are characterized in class 0 in every model, and affectability can be under 20 V. "For parts with an ESD affectability under hundred volts the ESD facilitator need to characterize correlative rules"like showed in standard records ( 61 340-5). No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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The target The goal was to handle, exceptionally delicate and costly electronic supplies by individuals in standing-up-position. ESDS (ESD delicate segments) are declared as exceptionally touchy. The edge ESD in human body model is reported at around 20 V. Coveralls are antistatic/dissipative. The other exemplary types of gear and principles are regarded. The utilization of antistatic wrist strap entrains vast difficulties.  So we need to utilize the floor as essential approach to take out static charges . In this design, individuals strolling with conductive shoes must not build up a static charge > 10 V (10 V consider an edge of 6 db(1/2) versus ESD affectability of parts). No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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The execution of a deck framework can be described by the accompanying details Body voltage era (BVG) as low as could be allowed: < 10 V for our situation, Resistance to ground (Rtg): Lowest esteem must consider security of people. Most elevated quality must ensure the ends of electrostatic charges and a low charge gathering. Surface Resistivity (Rs): Same requirements with respect to imperviousness to ground (Rtg) Decay time (Td). The quality must be sufficiently low to take out accuse in time good of the human action. No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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How does the friction based electricity is produced? The friction based electricity is for the most part produced by tribo-power, because of the mix, rubbing, between sole shoe and deck covering.  If the resistance between sole shoe and ground can\'t take out the charges, there is amassing of charges at sole shoe level. At that point by impact, charges present on sole shoe draw in the inverse charge at the feet of individual who is charged by influence.  As body is a conductor, the proportional charges are available at the level of his hands. The charges equalization is got when charge era is equivalent as charges end. The potential acquired is equivalent to BVG. The rearranged proportionate electrical chart is given next page. No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Equivalent electrical chart BVG = I (g). Rtg 1* ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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BVG estimations Only couple of producers give information about this parameter. These estimations are done after STM ESD 97-2 detail (RD 9). They are finished with conductive shoes Transversal resistance < 10 M ohm Materials A to F are sap, Materials G and H are PVC carbon stacked. F line cover a few sap materials tried. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Rtg Measurements Materials A to F are tar, Materials G and H are PVC carbon stacked. F line cover a few gum materials tried. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Rs Measurements Only couple of producers give informations about this parameter Materials A to F are tar; Materials G and H are PVC carbon stacked. Materials with low resistance < 10 K ohm are exclude in these outcomes and are not generally great on BVG parameter. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Theories… . U= RI Q = CV = it   S = 15*10 –6 (  r 1 -  r 2 ) (Where,  S is the surface charge thickness ,  r 1 and  r 2 are permitivity of both materials in contact see RD 20) Q =  s*S (Where S is the surface in contact)  V = Vo e t/RC ( t = 2.2 RC  V = 0,1 Vo; t = 5 RC  V = ~ 0 V) No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Remarks (1) Measurement of resistances on some gum flooring framework with ASTM tests (Ø 63.5 mm, weight 5 pounds) give extensive varieties. On same deck framework the utilization of IEC 61340-4-1 or 1081 tests give lower resistance values and better repeativity. In any case, if there should arise an occurrence of trouble with ASTM tests, frequently BVG is bigger than the lower resistance measured that we trust. Estimation on a decent ground surface framework normally give extremely uniform resistance esteem, even with ASTM tests. Resistance values under 100 M ohm is low enough.  So the best arrangement is to utilize the genuine setup taking after the archives ESD-STM 97-1-1999 with conductive shoes*(RD 8). *Not all ESD shoes give the same results however these with Rt < 10 7 ohm more often than not give great results. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Remarks (2) Measurements of Body Voltage Generation is characterized by various standard reports (NF EN 1815, NF P 62-001, ESD ASTM 97-2 1999 ). We pick American standard ESD ASTM 97-2 1999 this report advocate genuine arrangement ( conductive shoes, low relocation). For rot time estimations, standardization archive promoter to quantify from 1000 V to 100 V; however an American deck framework maker measure this parameter from 100 V to 10 V(it depends of necessities). ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Apparatus (1) Resistance estimations Megohmeter Measure voltage 10/100 V Resistance measure : 10 4 < R (ohm) ≧ 10 12 . Standardized tests : ASTM (hard to use on hard sap flooring framework) , IEC 61340-4-1, NF EN 1081. *Repeteative measures at 100 or 10 Volts are a hint of something better over the horizon to acquire à low BVG. Conductive Shoes Transversal resistance < 10 M ohm No charge, no release. ESD Conseils DUBAN Michel 26000 VALENCE - FRANCE

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Apparatus (2) Voltage estimations Charge analyser: Voltage > or = 1100 V Adjustable limits. time estimations From 0.1 to ~ 60 seconds. Realistic recorder: Thermometer/Hygrometer . Numerous comparable materials can be utilized. No charge, no release . ESD C

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