ANSI STM4.2-2012 The Protection of Electrostatic Discharge Susceptible Items ESD Protective Worksurfaces C Charge Dissipation Characteristics.pdf

1、ANSI/ESD STM4.2-2012 Reaffirmation of ANSI/ESD STM4.2-2006 For the Protection of Electrostatic Discharge Susceptible Items ESD Protective Worksurfaces Charge Dissipation Characteristics Electrostatic Discharge Association 7900 Turin Road, Bldg. 3 Rome, NY 13440 An American National Standard Approved

2、 April 23, 2012 ANSI/ESD STM4.2-2012 ESD Association Standard Test Method for the Protection of Electrostatic Discharge Susceptible Items - ESD Protective Worksurfaces Charge Dissipation Characteristics Approved February 12, 2012 ESD Association ANSI/ESD STM4.2-2012 Electrostatic Discharge Associati

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12、F DATA, INCOME OR PROFIT, LOSS OF OR DAMAGE TO PROPERTY AND CLAIMS OF THIRD PARTIES. Published by: Electrostatic Discharge Association 7900 Turin Road, Bldg. 3 Rome, NY 13440 Copyright 2012 by ESD Association All rights reserved No part of this publication may be reproduced in any form, in an electr

13、onic retrieval system or otherwise, without the prior written permission of the publisher. Printed in the United States of America ISBN: 1-58537-208-0DISCLAIMER OF WARRANTIES DISCLAIMER OF GUARANTY LIMITATION ON ESDAs LIABILITY CAUTION NOTICE ANSI/ESD STM4.2-2012 i (This foreword is not part of ESD

14、Association Standard Test Method ANSI/ESD STM4.2-2012) FOREWORD The test methods outlined in this standard were developed to further characterize the ability of ESD Control worksurfaces to dissipate static charge from conductive objects placed on them. Although the resistive properties of worksurfac

15、es give the user a “relative“ indication of their ability to dissipate charge, other factors such as contact resistance between the object and the worksurface, worksurface hardness and surface finish, and ambient relative humidity also affect their charge dissipation efficiency. This standard test m

16、ethod1provides for a worksurface test apparatus and conductive charged object configuration designed to give a better perspective as to the charge dissipation characteristics of worksurfaces based on the factors mentioned above. It is intended for qualification purposes only and should only be used

17、in a laboratory environment. Specific environments are required for both conditioning and testing of samples. This document was originally designated ESD STM4.2-1998 and approved on February 8, 1998. ANSI/ESD STM4.2-2006 was a reaffirmation of ESD STM4.2-1998 and was approved on February 26, 2006. A

18、NSI/ESD STM4.2-2012 is a reaffirmation of ANSI/ESD STM4.2-2006 and was approved on February 12, 2012. Three editorial changes were made from the 2006 version: added boilerplate Personnel Safety section; classified Annex A as informative; and classified Annex B as normative. At the time ANSI/ESD STM4

19、.2-2012 was prepared, the 4.0 Worksurfaces Subcommittee had the following members: Dale Parkin, Chair Seagate Technology Brent Beamer 3M Kevin Duncan, TAS Rep Seagate Technology Robert Vermillion RMV Technology Group, LLC. At the time ESD STM4.2-1998 was prepared, the 4.0 Worksurfaces Subcommittee h

20、ad the following members: Dale Parkin, Chair IBM Brent Beamer Static Control Components Larry Burich Lockheed-Martin Larry Green USAF Tim Jarrett Guidant Corp. William Klein K&S Laboratories Ron Schwartz Stanley Storage Systems Shane Wooldridge Kewaunee Scientific 1ESD Association Standard Test Meth

21、od (STM): A definitive procedure for the identification, measurement and evaluation of one or more qualities, characteristics or properties of a material, product, system or process that yield a reproducible test result. ANSI/ESD STM4.2-2012 ii The following individuals made significant contribution

22、s to ESD STM4.2-1998: Ben Baumgartner Lockheed-Martin Dave Deigan AFM Inc. Steve Gerken USAF Capt. Victoria Gerken USAF Ron Gibson Celestica Jim Horvat USAF Ron Johnson Intel ANSI/ESD STM4.2-2012 iii TABLE OF CONTENTS 1.0 PURPOSE AND SCOPE 1 1.1 PURPOSE . 1 1.2 SCOPE . 1 2.0 REFERENCE PUBLICATIONS .

23、 1 3.0 DEFINITIONS . 1 4.0 PERSONNEL SAFETY 1 5.0 REQUIRED EQUIPMENT 2 5.1 TEST APPARATUS . 2 5.1.1 Disk Assembly 2 5.1.2 Test Sample Support Table . 2 5.1.3 Disk Raising/Lowering Mechanism (RLM) . 2 5.1.4 Control Panel and Contact Timer . 2 5.1.5 Test Cabling . 2 5.1.6 Disk Suspension Cord . 3 5.1.

24、7 Apparatus Housing . 3 5.2 CHARGE PLATE MONITOR . 3 5.3 COULOMB METER AND VOLTAGE SOURCE 3 5.4 OHMMETER 3 5.5 ENVIRONMENTAL CHAMBER . 3 6.0 TEST SAMPLES 3 7.0 TEST SAMPLE PREPARATION / CONDITIONING . 3 8.0 TEST PROCEDURES 4 8.1 MEASUREMENT OF DISK ASSEMBLY CAPACITANCE . 4 8.2 DISK ISOLATION AND SYS

25、TEM VERIFICATION 4 8.3 SAMPLE TESTING 5 8.3.1 Pretest Preparations 5 8.3.2 Charge Dissipation Test . 5 9.0 DATA REPORTING . 5 9.1 SAMPLE DATA REPORTING SHEET . 6 9.2 DATA REPORTING SHEET 7ANSI/ESD STM4.2-2012 iv FIGURES Figure 1: Charge Dissipation Test Apparatus 8 Figure 2: Disk Assembly . 9 Figure

26、 3: Charge Plate Detail . 9 TABLES Table 1: Summary of Results of Capacitance Calculation 4 ANNEXES Annex A (Informative): Interpretation of Data 10 Annex B (Normative): Triboelectric Contribution Test 11 ESD Association Standard Test Method ANSI/ESD STM4.2-2012 1 ESD Association Standard Test Metho

27、d for the Protection of Electrostatic Discharge Susceptible Items - ESD Protective Worksurfaces - Charge Dissipation Characteristics 1.0 PURPOSE AND SCOPE 1.1 Purpose The purpose of this standard test method is to aid in determining the ability of ESD protective worksurfaces to dissipate charge from

28、 a conductive test object placed on them. This ability may not be revealed through standard resistance measurements as outlined in ANSI/ESD S4.1. 1.2 Scope This document provides a test method that measures the charge dissipation characteristics of worksurfaces. To accomplish this, a conductive test

29、 object is charged, placed on the worksurface under test, and then removed. The resultant charge on the test object is an indicator of the ability of the tested worksurface to dissipate charge from the test object placed on it. This is only applicable however for the test object specified within thi

30、s document. This standard test method is designed for use in a laboratory environment for qualification, evaluation or acceptance of worksurfaces and not for periodic testing. 2.0 REFERENCED PUBLICATIONS ESD ADV1.0, ESD Associations Glossary of Terms2 ANSI/ESD STM3.1, Ionization2ANSI/ESD S4.1, Works

31、urfaces - Resistive Characterization2 ANSI/ESD S6.1, Grounding2 ANSI/ESD STM11.11, Surface Resistance Measurement of Static Dissipative Planar Materials2 MIL-T-43435-1989, Tape, Lacing & Tying33.0 DEFINITIONS The terms used in the body of this document are in accordance with the definitions found in

32、 ESD ADV1.0, ESD Associations Glossary of Terms. 4.0 PERSONNEL SAFETY The procedures and equipment described in this document may expose personnel to hazardous electrical conditions. Users of this document are responsible for selecting equipment that complies with applicable laws, regulatory codes a

33、nd both external and internal policy. Users are cautioned that this document cannot replace or supersede any requirements for personnel safety. Ground fault circuit interrupters (GFCI) and other safety protection should be considered wherever personnel might come into contact with electrical sources

34、. Electrical hazard reduction practices should be exercised and proper grounding instructions for equipment shall be followed. 2ESD Association, 7900 Turin Road, Bldg. 3, Rome, NY 13440-2069, 315-339-6937, www.esda.org 3Defense Printing Service Detachment Office, Bldg. 4D (NPM-DODSSP), 700 Robbins A

35、ve., Philadelphia, PA 19111-5094, 215-697-5164 ANSI/ESD STM4.2-2012 2 5.0 REQUIRED EQUIPMENT 5.1 Test Apparatus The test apparatus and configuration used in this standard test method is shown in Figure 1. It includes a disk assembly, test sample support table, disk raising/lowering mechanism (RLM),

36、control panel and contact timer, test cabling, disk suspension cord and apparatus housing. 5.1.1 Disk Assembly The disk assembly used in this standard is shown in Figure 2. It consists of a 15.24 .254 cm (6 inches 1/10 inch) circular, conductive disk (i.e. non-anodized aluminum) and a support struct

37、ure used to suspend it from the disk RLM. The disk assembly shall have a maximum capacitance of 15 pF as measured in accordance with Annex B of ANSI/ESD STM3.1. It shall have a weight of 227 grams ( 5 grams). Dimensional tolerances of the disk assembly and its components are shown in Figure 2. 5.1.2

38、 Test Sample Support Table The support table is used to support the tested worksurface material and provide parallelism between the tested worksurface material and the lowered/raised disk assembly. The support table should be capable of adjusting test sample height such that a common distance is mai

39、ntained between the disk assembly and the worksurface prior to charge dissipation and triboelectrification testing. It must be made of an electrically insulative material ( 1.0 x 1012ohms, in accordance with ANSI/ESD STM11.11) and have sufficient thickness to rigidly support the test sample. It shal

40、l be 60.96 1.27 cm (24 0.5 inches) square. 5.1.3 Disk Raising/Lowering Mechanism (RLM) The test apparatus shall contain a mechanism used to lower and raise the disk assembly to and from the tested worksurface. Any process may be used to accomplish this task (i.e. hydraulic, pneumatic, etc.) as long

41、as the raising/lowering speed is controllable and provides uniform stroke movement and stability to the suspended disk assembly. The RLM must also be capable of suspending the disk assembly above the tested work surface while being electrically isolated from it. The RLM must be controlled such that

42、a specified contact time between the disk assembly and the tested worksurface is maintained. 5.1.4 Control Panel and Contact Timer A control panel and contact timer shall be used to activate the RLM and control the time in which the disk assembly is in contact with the test sample. Contact time shal

43、l be specified in the test procedure. 5.1.5 Test Cabling The specified test voltage is applied to the disk assembly from a charge plate monitor through test cabling. The test cabling also provides the electrical connection between the disk assembly and the charge plate monitor when monitoring the re

44、sultant disk assembly voltage after it is raised from the sample. The entire cable length shall be no greater than 121.92 cm (4 feet) in length and consist of two bonded portions. The first portion shall consist of 1 meter of insulated high voltage wire (40KV minimum). It shall be electrically bonde

45、d to a smaller 30 cm (11.7 inches) section of insulated (28 gauge or greater) wire. The high voltage wire end of the cable is connected to the isolated plate of the charge plate monitor and the smaller wire end is connected to the disk assembly. The cable shall not contact any portion of the test ap

46、paratus between the disk assembly and the charge plate monitor. This can be accomplished through an electrically insulative standoff material clamped to the test apparatus housing. The use of this isolation technique as well as the specified wire types ensures electrical isolation of the disk assemb

47、ly. Test cable acceptability is verified through the Disk Isolation/System Verification Test outlined herein. ANSI/ESD STM4.2-2012 3 5.1.6 Disk Suspension Cord The disk assembly shall be suspended and electrically isolated from the RLM. Braided nylon lacing tape / cord in accordance with MIL-T-43435

48、, Type I, Size 5, Finish B or equivalent is recommended. 5.1.7 Apparatus Housing It is recommended that the suspended disk assembly, test sample support table and test sample be contained within a grounded conductive housing. The housing provides some limited shielding from external noise or EMI sou

49、rces and a ground point for the worksurface test samples. Its size is dependent on overall system design but must accommodate all test apparatus components, as a minimum, the disk assembly, test sample support table, and test sample. 5.2 Charge Plate Monitor A) The conductive plate shall be 15.24 x 15.24 cm (6 x 6 inches) with a minimum capacitance of 15 pF when mounted in the test fixture without electrical hookups. The total capacitance of the test circuit, with plate, shall be 20 2 pF. B) There shall be no objects, grounded or otherwise, closer than dimension “A“ of