1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSemiconductor devices Micro-electromechanical devicesPart 8: Strip bending test method for tensile property measurement of thin filmsBS EN 62047-8:2011National forewordThis Briti
2、sh Standard is the UK implementation of EN 62047-8:2011. It is identical to IEC 62047-8:2011.The UK participation in its preparation was entrusted to Technical Committee EPL/47, Semiconductors.A list of organizations represented on this committee can be obtained on request to its secretary.This publ
3、ication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011ISBN 978 0 580 60629 8 ICS 31.080.99Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under th
4、e authority of the Standards Policy and Strategy Committee on 30 June 2011.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 62047-8:2011EUROPEAN STANDARD EN 62047-8 NORME EUROPENNE EUROPISCHE NORM May 2011 CENELEC European Committee for Electrotechnical Standardiza
5、tion Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62047-8:2011 E ICS 3
6、1.080.99 English version Semiconductor devices - Micro-electromechanical devices - Part 8: Strip bending test method for tensile property measurement of thin films (IEC 62047-8:2011) Dispositifs semiconducteurs - Dispositifs microlectromcaniques - Partie 8: Mthode dessai de la flexion de bandes en v
7、ue de la mesure des proprits de traction des couches minces (CEI 62047-8:2011) Halbleiterbauelemente - Bauelemente der Mikrosystemtechnik - Teil 8: Streifen-Biege-Prfverfahren zur Messung von Zugbeanspruchungsmerkmalen dnner Schichten (IEC 62047-8:2011) This European Standard was approved by CENELEC
8、 on 2011-04-18. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards
9、may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified
10、to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lith
11、uania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 62047-8:2011EN 62047-8:2011 - 2 - Foreword The text of document 47F/71/FDIS, future edition 1 of IEC 62047-8, prepared by SC 47F, Micro-electrome
12、chanical systems, of IEC TC 47, Semiconductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62047-8 on 2011-04-18. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall n
13、ot be held responsible for identifying any or all such patent rights. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2012-01-18 latest date by which the national standards co
14、nflicting with the EN have to be withdrawn (dow) 2014-04-18 _ Endorsement notice The text of the International Standard IEC 62047-8:2011 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the st
15、andards indicated: IEC 62047-2:2006 NOTE Harmonized as EN 62047-2:2006 (not modified). IEC 62047-3:2006 NOTE Harmonized as EN 62047-3:2006 (not modified). _ BS EN 62047-8:2011 2 62047-8 IEC:2011 CONTENTS 1 Scope . . 5 2 Normative references . 5 3 Terms and definitions . 5 4 Test apparatus . . 5 4.1
16、General . 5 4.2 Actuator 6 4.3 Load tip . 6 4.4 Alignment mechanism 6 4.5 Force and displacement sensors 6 4.6 Test environment. 6 5 Test piece . . 6 5.1 General . 6 5.2 Shape of test piece . 7 5.3 Measurement of test piece dimension . . 7 6 Test procedure and analysis 8 6.1 General . 8 6.2 Data ana
17、lysis . 8 7 Test report. . 9 Annex A (informative) Data analysis: Test results by using nanoindentation apparatus . . 10 Annex B (informative) Test piece fabrication: MEMS process . . 13 Annex C (informative) Effect of misalignment and geometry on property measurement . . 15 Bibliography . 18 Figure
18、 1 Thin film test piece . 7 Figure 2 Schematic of strip bending test . 9 Figure A.1 Three successive indents for determining the reference location of a test piece 10 Figure A.2 A schematic view of nanoindentation apparatus . 11 Figure A.3 Actuator force vs. deflection curves for strip bending test
19、and for leaf spring test 11 Figure A.4 Force vs. deflection curve of a test piece after compensating the stiffness of the leaf spring . 12 Figure B.1 Fabrication procedure for test piece 13 Figure C.1 Finite element analysis of errors based on the constitutive data of Au thin film of 1 m thick 16 Fi
20、gure C.2 Translational (d) and angular ( , , ) misalignments . . 17 Table 1 Symbols and designations of a test piece . 7 BS EN 62047-8:201162047-8 IEC:2011 5 SEMICONDUCTOR DEVICES MICRO-ELECTROMECHANICAL DEVICES Part 8: Strip bending test method for tensile property measurement of thin films 1 Scope
21、 This international standard specifies the strip bending test method to measure tensile properties of thin films with high accuracy, repeatability, moderate effort of alignment and handling compared to the conventional tensile test. This testing method is valid for test pieces with a thickness betwe
22、en 50 nm and several m, and with an aspect ratio (ratio of length to thickness) of more than 300. The hanging strip (or bridge) between two fixed supports are widely adopted in MEMS or micro-machines. It is much easier to fabricate these strips than the conventional tensile test pieces. The test pro
23、cedures are so simple to be readily automated. This international standard can be utilized as a quality control test for MEMS production since its testing throughput is very high compared to the conventional tensile test. 2 Normative references The following referenced documents are indispensable fo
24、r 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. NONE 3 Terms and definitions For the purposes of this document the following terms and definitions apply
25、. 3.1 deflection w displacement of a test piece at the middle of the length, which is measured with respect to the straight line connecting two fixed ends of the test piece 3.2 deflection angle angle between the deformed test piece and the straight line connecting two fixed ends of the test piece NO
26、TE Test piece in this document is often referred to as a strip bending specimen. 4 Test apparatus 4.1 General A test apparatus is composed of an actuator, a load-sensor, a displacement sensor, and alignment mechanism as other mechanical testers such as micro-tensile tester and BS EN 62047-8:2011 6 6
27、2047-8 IEC:2011 nanoindentation apparatus. A test piece in a form of strip is very compliant and experiences large deflection under a small load when comparing it with a micro-tensile test piece with similar dimensions. In this respect, the load-sensor should have an excellent resolution and the dis
28、placement sensor should have a long measuring range. Details on each component of test apparatus are described as follows. 4.2 Actuator All actuating devices that are capable of linear movement can be used for the test, e.g. piezoelectric actuator, voice coil actuator, servo motor, etc. However, a d
29、evice with fine displacement resolution is highly recommended due to small dimensions of the test piece. The resolution shall be better than 1/1 000 of maximum deflection of test piece. 4.3 Load tip The load tip which applies a line contact force to the test piece is shaped like a conventional wedge
30、 type indenter tip and can be made of diamond, sapphire or other hard materials. The radius of the tip shall be comparable to or larger than the thickness of the test piece, and less than L/50 (refer to Annex C.3). 4.4 Alignment mechanism The load tip shall be installed on the test apparatus aligned
31、 with the load and the displacement measuring axes, and the misalignment shall be less than 1 degree. The load tip shall be also aligned to the surface of the test piece with the deviation angles less than 1 degree (refer to Annex C for definition of deviation angles and error estimation of misalign
32、ment). It is desirable to equip the apparatus with tilt stages for adjusting the deviation angle. The load tip is to be positioned at the centre of the test piece and the positional accuracy shall be less than L/100. 4.5 Force and displacement sensors Force and displacement sensors shall have resolu
33、tions better than 1/1 000 of the maximum force and deflection during the test. The accuracy of the sensors shall be within 1 % of the range. The displacement sensors can be capacitive type, LVDT type, or optical type with acceptable resolution and accuracy. In practice, the deflection can be measure
34、d from the motion of the load tip using a capacitive sensor or from the deflection of the test piece using an optical method. 4.6 Test environment It is recommended to perform a test under constant temperature and humidity. Temperature change can induce thermal drift during deflection measurement. T
35、he temperature change or thermal drift shall be checked before and after the test. 5 Test piece 5.1 General The test piece shall be prepared by using the same fabrication process as the actual device fabrication. To minimize the size effect of a test piece, the structure and size of the test piece s
36、hall be similar to those of the device components. There are many fabrication methods of the test piece depending on the applications. As an example, the fabrication of the test piece based on MEMS process is described in Annex B. A lot of strip bending test pieces can be fabricated on a die or a su
37、bstrate. BS EN 62047-8:201162047-8 IEC:2011 7 5.2 Shape of test piece The shape of test piece and symbols are given in Figure 1 and Table 1, respectively. The test piece shall be designed to minimize the bending moment effect. In order to minimize the effect, the maximum deflection shall be more tha
38、n 40 times the thickness of the test piece, and the length of the test piece shall be more than 300 times the thickness of the test piece, and the width shall be more than 10 times the thickness of the test piece, and the length shall be 10 times larger than the width. The thickness of the substrate
39、 shall be more than 500 times that of the test piece. The dimension of the substrate is limited by the capacity of the test apparatus. The geometry of the fixed ends supporting the test piece can affect the test results. When etching the sacrificial layer and the supporting substrate of test pieces,
40、 the region beneath the test pieces can be over-etched, and this is called by under-cut. The under-cut at the fixed ends shall be minimized (anisotropic etching would be desirable rather than isotropic etching). Figure 1 Thin film test piece Table 1 Symbols and designations of a test piece Symbol Un
41、it Designation l1l2l3m m m Length of a test piece (=2L) Width of a test piece (=B) Thickness of a test piece (=h) 5.3 Measurement of test piece dimension To analyze the test results, the accurate measurement of the test piece dimensions is required since the dimensions are used to extract mechanical
42、 properties of test materials. The length (2L), width (B), and thickness (h) shall be measured with very high accuracy with less than 5 % error. Useful information on thickness measurement can be found in Annex C of 11and in Clause 6 of 2. 1Figures in square brackets refer to the Bibliography. IEC 4
43、99/11 BS EN 62047-8:2011 8 62047-8 IEC:2011 6 Test procedure and analysis 6.1 General a) The substrate containing test pieces is attached to a sample holder. There are some recommendable methods for the sample attachment, such as magnetic attachment, electrostatic gripping, adhesive gluing, etc. b)
44、The translational and angular misalignment between the load tip and the test piece can affect the test results (refer to Figure C.2), and should be checked using an optical microscope. The misalignment error and the guideline for alignment are described in Annex C. c) It is necessary to determine su
45、rface location of a test piece at the beginning of the test. The surface location is the position of the top surface of the test piece in the vertical direction when the strip deforms by the vertical movement of the load tip. This surface location can be determined by optical inspection using an opt
46、ical microscope, or be determined by three successive indents. When the load tip touches the strip, the slight change in the strip configuration can be observed and identified using the optical microscope. The detailed method for determining the surface location using three successive indents is des
47、cribed in A.3. d) The test is performed under a constant displacement rate until the strip ruptures. The displacement rate of sL / 10 4 or sL / 10 3 is recommended, which leads to the strain rate of approximately s /10 15 or s /10 14 , respectively when the strain reaches 0,5 %. This method applies
48、to strain rate insensitive materials since the strain rate changes during the test. 6.2 Data analysis To obtain an actual force and deflection data of a test piece from the experimental results, several compensations may be required depending on the test apparatus. As an example, the data analysis p
49、rocedures are described in Annex A for the case of a nanoindentation apparatus. These procedures can provide useful information for other types of apparatus. From the force and deflection measurements, stress and strain can be estimated by the following Equations (1) and (2). The equations are derived on the assumptions of negligible bending moment effect and uniform strain throughout the test piece 1-3. See Figure 2. F 2Bh sin= , (1
