1、BRITISH STANDARDBS EN 15042-1:2006Thickness measurement of coatings and characterization of surfaces with surface waves Part 1: Guide to the determination of elastic constants, density and thickness of films by laser induced surface acoustic wavesThe European Standard EN 15042-1:2006 has the status
2、of a British StandardICS 17.040.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 15042-1:2006This British Standard was published under the au
3、thority of the Standards Policy and Strategy Committee on 31 May 2006 BSI 2006ISBN 0 580 48285 5National forewordThis British Standard is the official English language version of EN 15042-1:2006.The UK participation in its preparation was entrusted to Technical Committee STI/33, Electrodeposited and
4、 related coatings, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Cata
5、logue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its cor
6、rect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests inform
7、ed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 27 and a back cover.The BSI copyright notice displayed in this document indicates when the document wa
8、s last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15042-1April 2006ICS 17.040.20English VersionThickness measurement of coatings and characterization ofsurfaces with surface waves - Part 1: Guide to the determinationof elastic co
9、nstants, density and thickness of films by laserinduced surface acoustic wavesMesure de lpaisseur des revtements et caractrisationdes surfaces laide dondes de surface - Partie 1 : Guidepour la dtermination des constantes lastiques, de lamasse volumique et de lpaisseur des films laidedondes acoustiqu
10、es de surface gnres par laserSchichtdickenmessung und Charakterisierung vonOberflchen mittels Oberflchenwellen - Teil 1: Leitfadenzur Bestimmung von elastischen Konstanten, Dichte undDicke von Schichten mittels laserinduzierten Ultraschall-OberflchenwellenThis European Standard was approved by CEN o
11、n 2 March 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be
12、obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Se
13、cretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Por
14、tugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means r
15、eservedworldwide for CEN national Members.Ref. No. EN 15042-1:2006: EEN 15042-1:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Symbols and abbreviations 5 5 Description of the method 6 6 Determination of the elastic constants, density thickness of
16、the film.16 7 Test report 19 Annex A (informative) Material data 21 Annex B (informative) Other methods for determining Youngs modulus of film materials .23 Bibliography 26 EN 15042-1:2006 (E) 3 Foreword This document (EN 15042-1:2006) has been prepared by Technical Committee CEN/TC 262 “Metallic an
17、d other inorganic coatings”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2006, and conflicting national standards shall be withdrawn at the lat
18、est by October 2006. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Irela
19、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 15042-1:2006 (E) 4 1 Scope This document gives guidance on methods of determining the elastic constants, density and thickness of thi
20、n films by laser-induced surface acoustic waves. It defines terms and described procedures. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest editi
21、on of the referenced document (including any amendments) applies. EN ISO 11145:2001, Optics and optical instruments Laser and laser-related equipment Vocabulary and symbols (ISO 11145:2001) International Vocabulary of Basic and General Terms in Metrology, 2nd Edition 1994, Beuth Verlag GmbH Berlin W
22、ien Zrich 3 Terms and definitions For the purposes of this document, the terms and definitions given in the International Dictionary of Metrology (VIM), EN ISO 11145:2001 and the following apply. 3.1 surface acoustic waves ultrasonic wave propagating along the surface of the material NOTE An importa
23、nt property of this wave is the penetration depth into the material, which depends on frequency. 3.2 phase velocity velocity at which the phase of the wave propagates 3.3 group velocity velocity at which the surface acoustic wave impulse induced by the laser propagates 3.4 dispersion dependence of t
24、he phase velocity on the frequency of the wave 3.5 dispersion relation ratio of angular frequency to the amount of the wave vector (wave number) 3.6 dispersion degree difference between phase and group velocity NOTE The dispersion degree is expressed as a percentage. 3.7 bandwidth frequency range of
25、 the amplitude spectrum EN 15042-1:2006 (E) 5 3.8 measuring length distance between the positions at which the dispersion curve is measured 3.9 thermo-elastic inducing inducing a surface acoustic wave by locally rapid heating of the test material as the result of absorbing a pulsed laser radiation 4
26、 Symbols and abbreviations a half length of the side of membrane for the membrane deflection technique; c phase velocity of the surface acoustic wave; c(E, E, , , , , d, fk) theoretical values of the phase velocity (calculated for example according 2); c(fk) phase velocity of the measured dispersion
27、 curve; C1, C2constants (functions of the Poissons ratio ); d film thickness;dSsubstrate thickness;dN nitriding depth; indentation depth; f frequency shift; d uncertainty of the film thickness; E uncertainty of Youngs modulus of the film; uncertainty of Poissons ratio of the film; uncertainty of the
28、 density of the film; E uncertainty of Youngs modulus of the substrate; uncertainty of Poissons ratio of the substrate; uncertainty of the density of the substrate; E* Youngs modulus; E Youngs modulus of the film; E Youngs modulus of the substrate; EoYoungs modulus of the indenter; EIYoungs modulus
29、determined by indenter test; ELAYoungs modulus determined by the laser-acoustic method; fkfrequency values of the measured dispersion curve; f frequency;f0resonance frequency of the resonance test method; F force; h deflection of membrane deflection technique; hpplastic indentation depth of the inde
30、nter test; k magnitude of the wave vector; lightwavelength of the light of Brillouin-scattering technique; p pressure of the membrane deflection technique; * Poissons ratio; EN 15042-1:2006 (E) 6 Poissons ratio of the film; Poissons ratio of the substrate; oPoissons ratio of the indenter; scattering
31、 angle of the Brillouin-scattering method; * density; density of the film; density of the substrate; Eresidual stress; angular frequency; TAannealing temperature; U voltage amplitude. 5 Description of the method 5.1 General principles The elastic modulus (Youngs modulus) of the film essentially dete
32、rmines the mechanical behaviour of the coated material, the development of residual stresses, the mechanical energy induced by externally loading the coated surface, influencing creation and growth of cracks in the film and, therefore, influencing essentially the failure behaviour of the coated mate
33、rial. Especially for hard coatings, Youngs modulus correlates with hardness that can be measured only with increasing error for reducing film thickness. The structure of coatings can vary within a wide range, depending on the deposition process. This accompanies a Youngs modulus of the film which va
34、ries considerably. The value tabulated for the bulk material therefore is only a very rough estimation for the material deposited as film. They are given for some selected materials in Annex A. Consequently, measuring the film modulus is a method for controlling the film quality and monitoring the t
35、echnological process. For measuring Youngs modulus of the film, several static and dynamic techniques are used, such as the membrane deflection test, indentation test, Brillouin-scattering, ultrasonic microscopy and resonance vibration test. An overview of the principles of these alternatives is giv
36、en in Annex B. These methods are characterised to require special sample preparation, to be time-consuming, or to fail for films of sub-micrometer and nano-meter thickness. The laser-acoustic technique is a practicable method for reproducibly determining Youngs modulus of films with thickness down t
37、o less than 10 nm without special sample preparation. The technique also enables the film thickness to be measured and provides access to the film density. The method can also be used to characterise layers with gradually varying properties perpendicular to the surface as created by transition harde
38、ning and nitriding steels or machining the surface of semiconductor materials. The applicability of the method can be limited by the ultrasonic attenuation of the test material. 5.2 Surface acoustic waves 5.2.1 Properties The test method is based on measuring the dispersion of surface acoustic waves
39、 that have a vibration component perpendicular to the surface. Surface acoustic waves propagate along the surface of the test sample. For isotropic media, their penetration depth is defined to be the distance to the surface where the wave amplitude is decreased to 1/e of the amplitude at the surface
40、 A (Figure 1). Approximately, the penetration depth can be equated with the EN 15042-1:2006 (E) 7 wavelength . The penetration depth of the surface acoustic wave reduces with increasing frequency, following the relation: fc= (1) where c is the phase velocity, in m/s; f is the frequency, in Hz. The p
41、hase velocity depends on the elastic constants and the density of the material. For a homogeneous isotropic half-space, the following approximation is used ()+=vEvvc1112,187,0(2) where vis the Poissons ratio; Eis the Youngs modulus, in N/m2; is the density, in kg/m3. Equation (2) does not apply to a
42、nisotropic materials which are more complex as described in 2. Key 1 film 2 substrate 3 amplitude within the material A amplitude at the surface AA/e = 0,37A123123AA/e = 0,37A1a) Low frequency: long wavelength, high penetration depth, little effect of the film 1b) High frequency: short wavelength, l
43、ow penetration depth, large effect of the film Figure 1 Properties of the surface acoustic waves EN 15042-1:2006 (E) 8 5.2.2 Surface acoustic waves in coated materials The surface wave velocity of a material varies by coating with a film with physical properties deviating from the substrate (see Fig
44、ure 1). It also depends on the elastic properties and the density of film and substrate material and the ratio of film thickness to wavelength. For a homogeneous isotropic film on homogeneous isotropic substrate, the following general relation applies: ()/, dvEvEckc = (3) where c is the phase veloci
45、ty, in m/s; is the circular frequency, in Hz; k is the magnitude of wave vector, in 1/m; E is the Youngs modulus of the substrate, in N/m2; v is the Poissons ratio of the substrate; is the density of the substrate, in kg/m3; E is the Youngs modulus of the film, in N/m2; v is the Poissons ratio of th
46、e film; is the density of the film, in kg/m3; d is the thickness of the film in m; is the wavelength, in m. Equation (3) is the dispersion relation for the surface wave propagating in coated materials. The implicit form of this relation is deduced from the boundary conditions of stress and displacem
47、ent components at the surface and the interface between film and substrate 2. For anisotropic film and substrate materials, the elastic constants Cijare used instead of Youngs modulus and Poisson ratio. The effect of the film on the wave propagation increases with increasing frequency of the wave du
48、e to its reducing penetration depth. This makes the wave velocity dependent on frequency. Figure 2 shows three characteristic cases. EN 15042-1:2006 (E) 9 Key X axis = f, in MHz Y axis = c, in m/s 1 Silicon (100) without film 2 Film of amorphous carbon on silicon: E = 411 Gpa = 2,69 g/cm3d = 5,58 m3
49、 Film of polyamide on silicon: E = 3,8 GPa = 1,4 g/cm3 d = 1,85 m Measured Calculated Figure 2 Two cases of dispersion of the surface acoustic wave in coated material compared to the case of non-coated material The film properties in Figure 2 (Youngs modulus, density, film thickness) were deduced from the measured curve by the inverse solution of the dispersion relation (3). The curves can be explained as follows.
