1、Designation:F 950 98Standard Test Method forMeasuring the Depth of Crystal Damage of a MechanicallyWorked Silicon Slice Surface by Angle Polishing and DefectEtching1This standard is issued under the fixed designation F 950;the number immediately following the designation indicates the year oforigina
2、l adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a technique to measure thedepth of damage,on
3、or beneath the surface of silicon wafersprior to any heat treatment of the wafer.Such damage resultsfrom mechanical surface treatments such as sawing,lapping,grinding,sandblasting,and shot peening.1.2 The principal application of this test method is fordetermining the depth of damage of the non-poli
4、shed backsurface that has had intentionally added work damage.1.3 The measurement is destructive since a specimen isprepared from a section of a silicon wafer.1.4 Depth of damage can be measured in the range of 5.0 to200 m using this method.1.5 This test method is intended for use in process control
5、where each individual location is resposible to determine theinternal repeatability to its satisfaction.1.6 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 hea
6、lth practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Section 9.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 122 Practice for Choice of Sample Size to Estimate aMeasure of Quality for a Lot or
7、 Process3F 532 Test Methods for Measuring Width of Defects inOptical Surfaces,Using Nomarski Differential Micros-copy4F 672 Test Method for Measuring Resistivity Profiles Per-pendicular to the Surface of a Silicon Wafer Using aSpreading Resistance Probe52.2SEMI Standard:C1 Specifications for Reagent
8、s63.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 damagea defect of the crystal lattice of a singlecrystal silicon specimen in the form of irreversible deforma-tion.The damage is the result of mechanical surface treatmentssuch as sawing,lapping,grinding,sandblasting,and shotpee
9、ning at room temperature without subsequent heat treat-ments.3.1.2 damage-free polishinga method of preparing a sur-face of a silicon specimen without creating any mechanicaldamage detectable by this method.3.1.3 bevel angle(a)the smaller of the angles between thewafer surface and the section plane.
10、(See Fig.1.)3.1.4 damage depth(Tz)the maximum thickness of thedamage region.The damage is revealed by a preferential etchthat removes silicon in the region of the deformation.Prefer-ential etching occurs because the chemical potential in theregion of the deformation is changed by the stress fieldsas
11、sociated with the deformation.The depth of damage isexpressed in micrometers.4.Summary of Test Method4.1 A silicon specimen is coated with silicon nitride by alow-pressure plasma method to a minimum thickness of 1 m.The specimen is then beveled at a small angle by a polishingtechnique that produces
12、no additional mechanical damage.Thebevel angle is measured.The beveled specimen is etched toreveal the damage.The length of the damage region ismeasured from the beveled edge on the beveled section.Thedepth of damage is then calculated from the relationshipbetween the measured damage length and the
13、sine of the bevelangle.5.Significance and Use5.1 This test method provides a means for measuring the1This test method is under the jurisdiction of ASTM Committee F-1 onElectronics and is the direct responsibility of Subcommittee F01.06 on SiliconMaterials and Process Control.Current edition approved
14、 May 10,1998.Published July 1998.Originallypublished as F 950 85.Last previous edition F 950 88(l993)1.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 14.02.4Discontinued;see 1993 Annual Book of ASTM Standards,Vol 06.01.5Annual Book of ASTM Standards,Vol 10.05.6Available
15、from the Semiconductor Equipment and Materials International,805E.Middlefield Rd.,Mountain View,CA 94043.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMdepth of mechanical damage in silicon wafer
16、s in the range from5 to 200 m.5.2 This test method can be used for process control orresearch and development purposes.It is not recommended foruse in material acceptance.6.Interferences6.1 Choice of Bevel AngleA bevel angle must be usedsuch that a magnification of the depth of damage is at least afactor of 5,or the damage may not be detected.Bevel anglesless than 544 min are not recommended because of difficultyin determining the surface edge due to the uneven surfacetopography generated by the
