1、 DEUTSCHE NORMJune 2006DIN EN 15042-1 ICS 17.040.20 Supersedes DIN 50992-1:2002-05 Thickness 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 waves Eng
2、lish version of DIN EN 15042-1:2006-06 Schichtdickenmessung und Charakterisierung von Oberflchen mittels Oberflchenwellen Teil 1: Leitfaden zur Bestimmung von elastischen Konstanten, Dichte und Dicke von Schichten mittels laserinduzierten Ultraschall-Oberflchenwellen Englische Fassung DIN EN 15042-1
3、:2006-06 Document comprises 29 pages No part of this standard may be reproduced without prior permission of DIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, has the exclusive right of sale for German Standards (DIN-Normen). English price group 13 www.din.de
4、www.beuth.de !,o-V“10.06 9761051DIN EN 15042-1:2006-06 2 National foreword This standard has been prepared by CEN/TC 262 Metallic and other inorganic coatings (Secretariat: United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Test
5、ing Standards Committee), Technical Committee NMP 161 Mess- und Prfverfahren fr metallische und andere anorganische berzge. Amendments This standard differs from DIN 50992-1:2002-05 as follows: a) DIN 50992-1:2002-05 has been taken over as a European Standard without any modifications. b) A bibliogr
6、aphy has been included. Previous editions DIN V 32939: 1998-05 DIN 50992-1: 2002-05 National Annex NA (informative) Bibliography DIN EN ISO 11145, Optics and optical instruments Laser and laser-related equipment Vocabulary and symbols EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15042-1April 20
7、06ICS 17.040.20English VersionThickness measurement of coatings and characterization ofsurfaces with surface waves - Part 1: Guide to the determinationof elastic constants, density and thickness of films by laserinduced surface acoustic wavesMesure de lpaisseur des revtements et caractrisationdes su
8、rfaces laide dondes de surface - Partie 1 : Guidepour la dtermination des constantes lastiques, de lamasse volumique et de lpaisseur des films laidedondes acoustiques de surface gnres par laserSchichtdickenmessung und Charakterisierung vonOberflchen mittels Oberflchenwellen - Teil 1: Leitfadenzur Be
9、stimmung von elastischen Konstanten, Dichte undDicke von Schichten mittels laserinduzierten Ultraschall-OberflchenwellenThis European Standard was approved by CEN on 2 March 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
10、EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (Englis
11、h, 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 Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech R
12、epublic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE
13、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 reservedworldwide for CEN national Members.Ref. No. EN 15042-1:2006: EEN 15042-1:2006 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative
14、 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 the film.16 7 Test report 19 Annex A (informative) Material data 21 Annex B (informative) Other methods for determining Youngs modulus o
15、f 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 and other inorganic coatings”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national sta
16、ndard, 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 latest by October 2006. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries
17、are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Swit
18、zerland 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 thin films by laser-induced surface acoustic waves. It defines terms and described procedures. 2 Normative references The following referen
19、ced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 11145:2001, Optics and optical instruments Laser and laser-rela
20、ted equipment Vocabulary and symbols (ISO 11145:2001) International Vocabulary of Basic and General Terms in Metrology, 2nd Edition 1994, Beuth Verlag GmbH Berlin Wien Zrich 3 Terms and definitions For the purposes of this document, the terms and definitions given in the International Dictionary of
21、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 important property of this wave is the penetration depth into the material, which depends on frequency. 3.2 phase velocity velocity at which th
22、e 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 the phase velocity on the frequency of the wave 3.5 dispersion relation ratio of angular frequency to the amount of the wave vector (wave
23、 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 the amplitude spectrum EN 15042-1:2006 (E) 5 3.8 measuring length distance between the positions at which the dispersion curve is measu
24、red 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 Symbols and abbreviations a half length of the side of membrane for the membrane deflection technique; c phase velocity of the surface
25、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 curve; C1, C2constants (functions of the Poissons ratio ); d film thickness;dSsubstrate thickness;dN nitriding depth; indentation depth
26、; 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 density of the film; E uncertainty of Youngs modulus of the substrate; uncertainty of Poissons ratio of the substrate; uncertainty of t
27、he 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 determined by indenter test; ELAYoungs modulus determined by the laser-acoustic method; fkfrequency values of the measured dispersion cu
28、rve; f frequency;f0resonance frequency of the resonance test method; F force; h deflection of membrane deflection technique; hpplastic indentation depth of the indenter test; k magnitude of the wave vector; lightwavelength of the light of Brillouin-scattering technique; p pressure of the membrane de
29、flection 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 angle of the Brillouin-scattering method; * density; density of the film; density of the substrate; Eresidual stress; angular frequency
30、; TAannealing temperature; U voltage amplitude. 5 Description of the method 5.1 General principles The elastic modulus (Youngs modulus) of the film essentially determines the mechanical behaviour of the coated material, the development of residual stresses, the mechanical energy induced by externall
31、y loading the coated surface, influencing creation and growth of cracks in the film and, therefore, influencing essentially the failure behaviour of the coated material. Especially for hard coatings, Youngs modulus correlates with hardness that can be measured only with increasing error for reducing
32、 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 varies considerably. The value tabulated for the bulk material therefore is only a very rough estimation for the material deposited as fil
33、m. 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 technological process. For measuring Youngs modulus of the film, several static and dynamic techniques are used, such as the membrane def
34、lection test, indentation test, Brillouin-scattering, ultrasonic microscopy and resonance vibration test. An overview of the principles of these alternatives is given in Annex B. These methods are characterised to require special sample preparation, to be time-consuming, or to fail for films of sub-
35、micrometer and nano-meter thickness. The laser-acoustic technique is a practicable method for reproducibly determining Youngs modulus of films with thickness down to less than 10 nm without special sample preparation. The technique also enables the film thickness to be measured and provides access t
36、o the film density. The method can also be used to characterise layers with gradually varying properties perpendicular to the surface as created by transition hardening and nitriding steels or machining the surface of semiconductor materials. The applicability of the method can be limited by the ult
37、rasonic 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 that have a vibration component perpendicular to the surface. Surface acoustic waves propagate along the surface of the test sample. Fo
38、r 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 A (Figure 1). Approximately, the penetration depth can be equated with the EN 15042-1:2006 (E) 7 wavelength . The penetration depth of
39、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 phase velocity depends on the elastic constants and the density of the material. For a homogeneous isotropic half-space, the following ap
40、proximation 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 anisotropic materials which are more complex as described in 2. Key 1 film 2 substrate 3 amplitude within the material A amplitude at the
41、 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, low 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 aco
42、ustic 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 Figure 1). It also depends on the elastic properties and the density of film and substrate material and the ratio of film thickness to wave
43、length. For a homogeneous isotropic film on homogeneous isotropic substrate, the following general relation applies: ()/, dvEvEckc = (3) where c is the phase velocity, 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/
44、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 the 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 dispersi
45、on relation for the surface wave propagating in coated materials. The implicit form of this relation is deduced from the boundary conditions of stress and displacement components at the surface and the interface between film and substrate 2. For anisotropic film and substrate materials, the elastic
46、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 due to its reducing penetration depth. This makes the wave velocity dependent on frequency. Figure 2 shows three characteristic cases. EN
47、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 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 ac
48、oustic 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. The velocity is in
49、dependent on the frequency for the non-coated silicon substrate. The diamond-like carbon film on the silicon makes the dispersion curve to increase. The wave velocity is higher for the film than for the substrate. The dispersion curve decreases with frequency for the silicon coated by a polyamide. The wave velocity is lower for the film than for the substrate. The shape of the dispersion curve characte
