1、Designation:F184497(Reapproved 2008)Standard Practice forMeasuring Sheet Resistance of Thin Film Conductors ForFlat Panel Display Manufacturing Using a Noncontact EddyCurrent Gage1This standard is issued under the fixed designation F1844;the number immediately following the designation indicates the
2、 year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes methods for measuring the sheetele
3、ctrical resistance of sputtered thin conductive films depos-ited on large insulating substrates(glass or plastic),used inmaking flat panel information displays.1.2 This practice is intended to be used with Test MethodsF673.This practice pertains to a“manual”measurementprocedure in which an operator
4、positions the measuring headon the test specimen and then personally activates the testapparatus.The resulting test data may be tabulated by theoperator,or,alternatively,sent to a computer-based datalogging system.Both Methods I and II of Test Methods F673(paragraphs 3.1 through 3.3.3 of Test Method
5、s F673)areapplicable to this practice.1.3 Sheet resistivity in the range 0.020 to 3000 per square(sheet conductance in the range 3 by 104to 50 mhos persquare)may be measured by this practice.The sheet resistanceis assumed to be uniform in the area being probed.NOTE1Typical manual test units,as descr
6、ibed in this practice,measure and report in the units“mhos per square”;this is the inverse of“ohms per square.”1.4 This practice is applicable to flat surfaces only.1.5 This practice is non-destructive.It may be used onproduction panels to help assure production uniformity.1.6 The values stated in S
7、I units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health pra
8、ctices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F673 Test Methods for Measuring Resistivity of Semicon-ductor Slices or Sheet Resistance of Semiconductor Filmswith a Noncontact Eddy-Current Gage(Withdrawn 2003)33.Summary of Pra
9、ctice3.1 This practice describes the preferred means of applyingTest Methods F673 to measure the electrical sheet resistance ofthin films on very large,flat,nonconducting substrates.Thesubstrate,oriented with the conducting thin film up,is placedbetween the transducers of the eddy current sensor ass
10、embly atthe point of interest.The test arrangement is illustrated in Fig.1.3.2 Atypical conductance apparatus is described in detail ina paper by Miller,Robinson,and Wiley.4This paper alsodiscusses skin-depth as a function of thickness and resistivity.3.3 A typical apparatus operates as follows:when
11、 a speci-men is inserted into the fixed gap between the two parallelsensing elements,or transducers,in a special oscillator circuit,eddy currents are induced in the specimen by the alternatingfield between the transducers.The current needed to maintainconstant voltage in the oscillator is determined
12、 internally;thiscurrent is a function of the specimen conductance.3.4 Further details are given in Test Methods F673,para-graphs 3.1 through 3.3.3.3.5 This practice includes calibration procedures for usingNIST Silicon Standard Reference Material5to ensure properoperation before testing panels.1This
13、 practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.17 on Sputter Metallization.Current edition approved June 15,2008.Published July 2008.Originallyapproved in 1997.Last previous edition approved in 2002 as F1844 97(2002).DOI:1
14、0.1520/F1844-97R08.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical s
15、tandard is referenced onwww.astm.org.4Miller,G.L.,Robinson,D.A.H.,and Wiley,J.D.,“Contactless Measurementof Semiconductor Conductivity by Radio Frequency-Free-Carrier PowerAbsorption,”Review of Scientific Instruments,Vol 47,No.7,July 1976.5Available from NIST,100 Bureau Dr.,Stop 3460,Gaithersburg,MD
16、 20899.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Significance and Use4.1 Resistivity is a primary quantity for characterization andspecification of coated glass plates used for flat panel displays.Sheet resistance is also a primary quantity for characterization,specification,and monitoring of thin film fabrication processes.4.2 This practice requires no specimen preparation.4.3 The eddy current method is non-destructive to the
