JP2009156725A - Thin film test piece structure, its manufacturing method, its tensile test method, and tensile testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurately a tensile test by using a test piece comprising a thin film material. <P>SOLUTION: This thin film test piece structure 1 used for the tensile test is equipped with a thin film test piece 2 provided with a test object part 2a and a load transfer part 2b successive thereto, and a support member 3 for supporting at least a part excluding the test object part 2a of the thin film test piece 2. The support member 3 has a test piece support part 3a bonded to the load transfer part 2b, a frame part 3c arranged on the periphery separated from the thin film test piece 2, and elastic connection parts 3d, 3e for connecting the test piece support part 3a relatively displaceably in a tensile direction to the frame part 3c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin film test piece structure used for a tensile test, a manufacturing method thereof, a tensile test method thereof, and a tensile test apparatus.

Micro devices such as a micro machine (Micro Electro Mechanical System: MEMS) and semiconductor parts are composed of minute members such as thin films. In order to improve the performance and reliability of these machines and devices, it is important to design after fully understanding the mechanical and electrical characteristics of the thin film material under the usage dimensions. Although electrical characteristics have been investigated relatively frequently so far, there are many mechanical characteristics that have not yet been clarified due to the difficulty of the testing technique. A typical method for evaluating mechanical properties is a tensile test. A tensile test for thin film materials reads the resistance load and displacement when a uniaxial tensile load is applied to the specimen, and the Young Most of them calculate the rate, fracture strength, yield stress and the like.
JP 2007-163257 A JP-A-6-109609

  However, the deformation behavior of the test piece in the uniaxial tensile test is unlikely to be the same as that under biaxial or multiaxial stress. Usually, micro structures with micro / nano-level thickness used for micromachines and microdevices often have a laminated structure of different materials, and most of them are under multiaxial stress conditions. The structures that exist under conditions are very limited. Therefore, in order to design the reliability of products composed of this minute structure, the deformation behavior of thin film materials must be fully understood not only under uniaxial stress conditions but also under multiaxial stress conditions. Is an urgent need.

  For example, Patent Documents 1 and 2 propose a biaxial tensile testing machine that pulls a test piece such as a rubber plate in the XY direction in a state of being gripped by a gripping tool. However, these biaxial tensile testing machines are not intended for small thin film materials. Therefore, even if a thin film material with extremely low rigidity of micro / nano thickness is applied as a test piece, the thin film test piece is not Since it is not twisted and kept in the correct position and posture, a test result with high accuracy cannot be obtained, and in the worst case, there arises a problem that the thin film test piece is torn.

  Therefore, an object of the present invention is to enable a tensile test to be performed with high accuracy using a test piece made of a thin film material.

  The present invention has been made in view of the above circumstances, and a thin film test piece structure according to the present invention is a thin film test piece structure used for a tensile test, and includes a test object portion and a load continuous thereto. A thin film test piece provided with a transmission part, and a support member that supports at least a part of the thin film test piece excluding the test target part, the support member being joined to the load transmission part A support part; a frame part arranged around the thin film test piece; and a connection part that connects the test piece support part to the frame part so as to be relatively displaceable in a tensile direction. It is characterized by.

  According to the above configuration, the test piece support portion of the support member is joined to the load transmitting portion of the thin film test piece, and the test piece support portion can be relatively displaced in the tensile direction with respect to the frame portion by the connecting portion. Since they are connected, the thin film test piece is configured to be difficult to twist while allowing displacement in the tensile direction. Therefore, it is possible to perform a tensile test with high accuracy while stably maintaining a correct position and posture using a test piece made of a thin film material. Moreover, since the thin film test piece is stably held by the support member, the thin film test piece can be easily handled, and damage during the handling of the thin film test piece can be prevented.

  The load transmitting unit may extend in a biaxial direction from the test target unit.

  According to the said structure, since the tensile force of a biaxial direction can be provided to a test object part, it becomes possible to perform a biaxial tension test stably.

  The connecting part may be provided symmetrically on both sides of the load transmitting part across the axial direction.

  According to the above configuration, since the paired connecting portions sandwiching the axial direction of the load transmitting portion are symmetrical, the position and posture of the thin film test piece are kept symmetrical with respect to the axial direction, so that the stable state Can perform a tensile test with high accuracy.

  The connection part may be composed of an elastic connection part that elastically connects the test piece support part to the frame part.

  According to the said structure, it becomes possible for a connection part to accept | permit the relative displacement of the tensile direction with respect to the flame | frame part of a test piece support part suitably, preventing the twist etc. of a thin film test piece.

  The elastic connecting portion may be formed of a spring linear body that is integrally formed of the same material as the test piece support portion and the frame portion and is formed in a distorted shape in plan view.

  According to the above configuration, the elastic connecting portion is formed in the shape of a spring wire, so that the elastic connecting portion is integrally formed of the same material as the test piece support portion and the frame portion, but can be elastically displaced in one direction. The connecting portion can be easily provided.

  The load transmitting portion and the test piece support portion may be formed with an engagement hole penetrating them.

  The spring linear body may have a thickness in a direction orthogonal to the plane larger than a width in a plane direction of the thin film test piece and the support member.

  According to the above configuration, the spring linear body has increased rigidity in the thickness direction, which is a direction orthogonal to the planar direction of the thin film test piece and the support member, so that the spring linear body is in an out-of-plane direction with respect to the plane. The deformation can be suppressed, and the thin film test piece can be suitably prevented from being twisted.

  According to the above configuration, even if the thin film test piece is not gripped, a tensile force can be applied to the thin film test piece by inserting the protrusion on the tensile test device side into the engagement hole. Can be prevented.

  A layer forming the same plane as the thin film test piece may be provided in the vicinity of the test target portion of the frame portion, and a mark facing the thin film test piece may be formed on an outer edge of the layer.

  According to the said structure, it becomes possible to grasp | ascertain the displacement state of a thin film test piece visually and quantitatively by recognizing a mark position on a picked-up image.

  The method for producing a thin film test piece structure of the present invention is a method for producing a thin film test piece structure used for a tensile test, wherein a test target portion and a continuous portion thereof are formed on one side of an unetched substrate made of a corrosive material. A step of forming a thin film test piece provided with a load transmitting portion, and a step of performing anticorrosion treatment of a required shape on at least a part of the other surface side of the unetched substrate excluding the test target portion in plan view, Etching the unetched substrate from the other surface side, a test piece support joined to the load transmitting part, a frame part arranged around the thin film test piece in plan view, Forming a support member having a connecting portion that connects the test piece support portion to the frame portion so as to be relatively displaceable in a tensile direction.

  According to the said manufacturing method, a thin film test piece structure can be manufactured finely and with high precision. Further, the manufactured thin film test piece structure has the test piece support portion of the support member joined to the load transmitting portion of the thin film test piece, and the test piece support portion is connected to the frame portion by the connecting portion. Therefore, the thin film test piece is hardly twisted and is stably held in a correct position and posture. Therefore, it is possible to perform a tensile test with high accuracy using a test piece made of a thin film material. Moreover, since the thin film test piece is stably held by the support member, the thin film test piece can be easily handled, and damage during the handling of the thin film test piece can be prevented.

  The tensile test method of the present invention is a method for subjecting the thin film test piece structure to a tensile test, and applying a tensile force to the load transmitting portion and the test piece support portion of the thin film test piece structure, The first tensile load and displacement are measured, and after the test target portion of the thin film test piece structure is broken, the tensile force is again applied to the load transmitting portion and the test piece support portion under the same conditions as the first time. The second tensile load and displacement are measured, and the tensile load and displacement measured at the second time are subtracted from the tensile load and displacement measured at the first time, respectively. And

  According to the above-described method, the thin film test piece can be stably pulled in a state in which the support member is bonded, and the tensile properties (tensile load) of the thin film test piece excluding the influence of the support member after the thin film test piece is broken. And displacement) can be obtained.

  The tensile test apparatus according to the present invention is an apparatus for performing a tensile test on the thin film test piece structure, wherein the frame portion of the support member of the thin film test piece structure is installed; and the thin film test A tensile load transmitting member for transmitting a tensile load to the load transmitting portion of the one-piece structure; a driving device for generating power for moving the tensile load transmitting member; and a power from the driving device for transmitting the tensile load to the tensile load transmitting member. And a load measuring device for measuring a load applied to the tensile load transmitting member, and a displacement measuring device for measuring a displacement of the tensile load transmitting member.

  According to the above configuration, the frame portion of the support member of the thin film test piece structure described above is installed on the installation base, and a tensile force is applied to the load transmitting portion of the thin film test piece structure, and the thin film test piece generated accordingly. It becomes possible to accurately measure the reaction force (tensile load) and displacement from the structure.

  The tensile load transmitting member may be configured to apply a biaxial tensile force to the thin film test piece structure.

  According to the said structure, a tensile test can be performed to a biaxial direction with respect to a thin film test piece structure.

  The tensile load transmission member has a base and an engagement protrusion that protrudes from the base and is inserted into the engagement hole of the thin-film test piece structure, and the installation base has a plurality of flat installation surfaces. And the base portion of the tensile load transmission member is positioned below a plane including the installation surface, and the engagement protrusion of the tensile load transmission member is above the plane including the installation surface. May protrude.

  According to the above configuration, the base of the tensile load transmitting member is in contact with the thin film test piece structure in a state where the engagement protrusion is inserted into the engagement hole of the thin film test piece structure placed on the installation surface of the installation table. Therefore, even when the flatness of the tensile load transmitting member is not sufficient, the thin film test piece structure can be maintained in the correct position and posture. In addition, since the installation table is an integral product, it is possible to save the trouble of adjusting the flatness of the installation surface when setting the tensile test apparatus at the test site.

  The tensile load transmission member extends in a direction away from the installation base, and the driving device is disposed below the tensile load transmission member and connected to the tensile load transmission member via the power transmission mechanism. May be.

  According to the said structure, since the drive device is arrange | positioned under the tensile load transmission member, compared with the case where it arranges in series with respect to the tensile load transmission member in the tension | pulling direction, the whole apparatus can be made compact.

  The power transmission mechanism includes a power point at which a driving force from the driving device acts, a point at which the driving force is transmitted to the tensile load transmission member, and a displacement at the point of action according to the principle of leverage than a displacement at the power point. You may have a fulcrum for making it increase.

  According to the above configuration, since the displacement generated by the drive device is amplified by the power transmission mechanism, the tensile load transmission member can be largely displaced even if the displacement generated by the drive device is small.

  As is apparent from the above description, according to the thin film test piece structure of the present invention, a tensile test can be performed with high accuracy using a test piece made of a thin film material, and damage during handling of the thin film test piece can be prevented. Can be prevented. Moreover, according to the manufacturing method of the thin film test piece structure of this invention, a thin film test piece structure can be manufactured finely and with high precision. Further, according to the tensile test method of the present invention, the thin film test piece can be stably pulled in a state where the support member is joined, and the influence of the support member is excluded after the thin film test piece is broken. It is possible to obtain the tensile properties of Further, according to the tensile test apparatus of the present invention, the frame portion of the support member of the thin film test piece structure is installed on the installation table, and a tensile force is applied to the load transmitting portion of the thin film test piece structure, and the tensile load and Displacement can be measured with high accuracy.

  Embodiments according to the present invention will be described below with reference to the drawings.

[Structure of thin film specimen structure]
FIG. 1 is a perspective view showing a thin film test piece structure 1 according to an embodiment of the present invention. FIG. 2 is a plan view of the thin film test piece structure 1. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is an enlarged perspective view showing the elastic connecting portion of the thin film test piece structure 1 and the vicinity thereof. In FIG. 2, for easy understanding, a thin film test piece 2 and a support member 3 described later are respectively hatched differently. As shown in FIGS. 1 to 4, the thin film test piece structure 1 excludes the test target portion 2 a and the thin film test piece 2 provided with the load transmitting portion 2 b continuous thereto, and the test target portion 2 a of the thin film test piece 2. And a supporting member 3 that supports the load transmitting portion 2b, and is used for a biaxial tensile test.

  The thin film test piece 2 is a thin film made of a metal (for example, aluminum) having a film thickness of 1 to 2 μm. The test target portion 2a has a quadrangular shape in plan view. The load transmitting portion 2b includes a first extending portion 2c that extends in four directions (XY directions) continuously from the test target portion 2a, and a first extending portion 2c that is continuous to the first extending portion 2c. The second extending portion 2d having a wider width and the engaging frame portion 2e having a square frame shape in a plan view having the engaging hole 5 at the center continuously to the second extending portion 2d. That is, two pairs of load transmitting portions 2b are provided so as to extend in the biaxial direction from the test target portion 2a.

  The support member 3 is made of a thin plate in which silicon oxide films 7 and 8 having a film thickness of 0.5 to 1.5 μm are formed on the upper and lower surfaces of a single crystal silicon plate 6 having a thickness of 100 to 300 μm. The wall thickness is larger than. The support member 3 includes a test piece support portion 3a joined to the lower surface of the load transmitting portion 2b of the thin film test piece 2, a square frame-shaped frame portion 3c arranged around the thin film test piece 2, and a test piece. It has elastic connecting portions 3d and 3e (connecting portions) for connecting the support portion 3a to the frame portion 3c so as to be relatively displaceable. The test piece support portion 3a is formed with an engagement hole 5 communicating with the engagement hole 5 of the engagement frame portion 2e. Moreover, the bracket part 3b protrudes in the test piece support part 3a in the direction away from the test object part 2a.

  The bracket portion 3b and the frame portion 3c are connected by the elastic connecting portion 3d on the outer side away from the test target portion 2a than the engagement hole 5, and are closer to the test target portion 2a than the engagement hole 5 is. On the inner side, a portion corresponding to the second extending portion 2d of the test piece support portion 3a and the frame portion 3c are connected by an elastic connecting portion 3e. The elastic connecting portions 3d and 3e are made of spring linear bodies formed in a twisted shape in plan view, and can be expanded and contracted in the tension direction. That is, the elastic coupling portions 3d and 3e are configured to be elastically deformed so that the test piece support portion 3a can be displaced relative to the frame portion 3c in the tensile direction.

  In the plane of the thin film test piece structure 1, the elastic connection portions 3d and 3e extend from the test piece support portion 3a and the bracket portion 3b to both sides in the direction perpendicular to the tensile direction, and the frame portions 3c on both sides thereof. It is connected to. The elastic connecting portions 3d and 3e are provided symmetrically on both sides of the load transmitting portion 2b with respect to the axial direction. Further, the spring linear bodies constituting the elastic coupling portions 3d and 3e have a thickness T in a direction perpendicular to the width W in the plane direction of the thin film test piece structure 1.

  FIG. 5 is an enlarged plan view showing the test target portion 2a of the thin film test piece structure 1 and its vicinity. As shown in FIGS. 1, 2 and 5, a dummy thin film layer 4 is formed on a part of the upper surface of the frame portion 3c of the support member 3 so as to form the same plane as the thin film test piece 2 in the vicinity of the test target portion 2a. ing. The dummy thin film layer 4 is formed of the same material and the same thickness as the thin film test piece 2. On the outer edge of the second extending portion 2d of the thin film test piece 2 in the vicinity of the first extending portion 2c, a small mark having a tapered shape protrudes toward the dummy thin film layer 4 in plan view. A tapered mark 4a protrudes from the outer edge of the dummy thin film layer 4 in a plan view facing the mark 2d1. Further, a tapered mark 2c1 protrudes from the first extending portion 2c of the thin film test piece 2 in plan view. That is, the state of the thin film test piece 2 can be recognized on the photographed image by the mark 4a of the dummy thin film layer 4 and the marks 2c1 and 2d1 of the thin film test piece 2. In addition, holes 2c2 and 4b for film thickness measurement are formed at predetermined positions of the second extending portion 2c and the dummy thin film layer 4 of the thin film test piece 2.

[Procedure for manufacturing thin-film specimen structure]
6A to 6F are cross-sectional views for explaining the manufacturing procedure of the thin-film test piece structure 1. First, as shown in FIG. 6A, a single crystal silicon plate 6 having a predetermined thickness (for example, 200 μm) is prepared as an unetched substrate made of a corrosive material, and a predetermined thickness is formed on the upper and lower surfaces thereof by thermal oxidation. (For example, 1 μm) of silicon oxide films 7 and 8 are formed. Next, as shown in FIG. 6B, aluminum is formed into a pattern shape to be the thin film test piece 2 with a predetermined thickness (for example, 2 μm) by sputtering. Next, as shown in FIG. 6C, a metal (for example, chromium) is formed on the upper and lower surfaces with a predetermined thickness (for example, 0.1 μm) to form protective films 9 and 10. However, the protective films 9 and 10 need not be metal.

  Next, as shown in FIG. 6D, the lower protective film 10 and the silicon oxide film 8 are formed in a predetermined shape by wet etching, and the etched lower protective film 10 and silicon oxide film 8 are used as anticorrosion masks. The single crystal silicon plate 6 is formed into a predetermined shape by dry etching from the side. Next, as shown in FIG. 6E, a silicon oxide film 7 on the upper surface side is formed in a predetermined shape by wet etching from the lower surface side. Finally, as shown in FIG. 6 (f), the protective film 9 on the upper surface side is removed by wet etching, and the thin film test piece structure 1 described above is completed.

[Configuration of tensile test system]
FIG. 7 is an overall view schematically showing a tensile test system 30 having the tensile test apparatus 20 according to the embodiment of the present invention. As shown in FIG. 7, the tensile test system 30 includes a tensile test apparatus 20 having a piezo actuator 35, a load cell 37, and a differential transformer 38, as will be described later. The piezo actuator 35 is connected to the computer 25 via the piezo controller 21 and the A / D converter 24. The load cell 37 is connected to the computer 25 via the load cell amplifier 22 and the A / D converter 24. The differential transformer 38 is connected to the computer 25 via the differential transformer amplifier 23 and the A / D converter 24. The computer 25 is connected to a CCD camera 26 for photographing the thin film test piece structure 1 (see FIG. 1) installed in the tensile test apparatus 20 from above.

[Configuration of tensile test equipment]
FIG. 8 is a perspective view showing a tensile test apparatus 20 according to the embodiment of the present invention. As shown in FIG. 8, the tensile test apparatus 20 includes a base 31 having a quadrangular shape in a plan view and a housing 32 having a substantially quadrangular shape in a plan view and a reverse concave shape in a cross-sectional view. ing. The housing 32 integrally includes a housing main body portion 32a, a power transmission mechanism 36, and connection spring portions 47 and 48 that connect the power transmission mechanism 36 to the housing main body portion 32a so as to be relatively displaceable. Wiring inlets 32b are opened at four corners of the housing body 32a.

  A mounting base 33 on which the frame part 3c of the support member 3 of the thin film test piece structure 1 (see FIG. 1) is installed is attached to the housing main body part 32a. Four tensile load transmission members 34 that transmit a tensile load to the load transmission portion 2b of the thin film test piece structure 1 (see FIG. 1) are provided in the vicinity of the installation base 33. Each tensile load transmission member 34 is connected to a power transmission mechanism 36 via a load cell 37 that is a load measuring device. The power transmission mechanism 36 is connected to a piezo actuator 35 (see FIG. 11), which is a drive device that is arranged hidden under the tensile load transmission member 34. A differential transformer 38 (LVDT: Linear Variable Differential Transformer), which is a displacement measuring device attached to the housing main body 32a, is connected to the tensile load transmitting member 34 in order to measure the displacement of the tensile load transmitting member 34. .

  That is, in the tensile test apparatus 20, the power of the four piezoelectric actuators 35 is transmitted to the tensile load transmission member 34 through the power transmission mechanism 36 and the load cell 37, respectively, so that the thin film test piece structure 1 (see FIG. 1). A biaxial tensile force in the XY direction is applied to the XY direction. At that time, the load applied to each tensile load transmission member 34 is measured by the load cell 37 and the displacement of each tensile load transmission member 34 is measured by the differential transformer 38. Yes.

  FIG. 9 is an enlarged perspective view showing the installation base 33 of the tensile test apparatus 20 and the vicinity thereof. As shown in FIG. 9, a square-shaped installation base recess 32c is provided in the center of the housing body 32a in plan view, and a rectangular installation table 33 is accommodated in the recess 32c in plan view. Yes. The installation base 33 is an integral product, and an upper surface 33a thereof is positioned above the housing main body 32a. On the upper surface 33a of the installation base 33, a constant width groove portion 33b extending in a constant width from the center in four directions (XY directions) and a widening groove portion 33c extending in the tension direction so as to widen from the constant width groove portion 33b are formed. Has been. In a portion adjacent to the constant width groove portion 33b on the upper surface 33a of the installation table 33, a flat installation surface 33d having a rectangular shape in plan view for installing the thin film test piece structure 1 (see FIG. 1) protrudes slightly upward. It is provided in the state.

  The tensile load transmission member 34 has a base portion 34a and an engagement protrusion 34b that protrudes upward from the base portion 34a and is inserted into the engagement hole 5 of the thin film test piece structure 1 (see FIG. 1). The base portion 34a is provided with an engaging protrusion 34b and is accommodated and disposed in the constant width groove portion 33b of the installation table 33. The wide width portion 34d and the widening portion 34d are accommodated and disposed in the widening groove portion 33c of the installation table 33. And a large portion 34e extending in the pulling direction away from the installation base 33. The base 34a is positioned below a horizontal plane including the installation surface 33d, and the engagement protrusion 34b protrudes above the horizontal plane including the installation surface 33d.

  FIG. 10 is an enlarged perspective view showing the power transmission mechanism 36 of the tensile test apparatus 20 and the vicinity thereof. FIG. 11 is an enlarged plan view showing the power transmission mechanism 36 of the tensile test apparatus 20 and the vicinity thereof. In FIG. 11, the housing main body 32a is hatched for easy understanding. As shown in FIGS. 10 and 11, the power transmission mechanism 36 includes a displacement amplifying unit 44 that receives power from an output unit 35 a of a piezo actuator 35 disposed below the tensile load transmission member 34, and a load cell to which the load cell 37 is fixed. The fixing portion 46 and an action point portion 45 serving as a relay portion for connecting the displacement amplifying portion 44 to the load cell fixing portion 46 are provided. In the inner space surrounded by the power transmission mechanism 36, there is a fixed wall portion 32d which is a part of the housing body portion 32 fixed to the base 31 (see FIG. 8) and to which the differential transformer fixture 39 is fixed. Has been placed. In the differential transformer fixture 39, a differential transformer 38 is sandwiched and fixed by a lower fixing member 41 and an upper fixing member 42, and the differential transformer 38 is connected to the tensile load transmission member 34 via a connecting shaft 43. Has been.

  As shown in FIG. 11, the displacement amplifying unit 44 of the power transmission mechanism 36 has a force point portion 44 a that is pressed in the tensile direction (the axial direction in which the tensile load transmitting member 34 moves) by the output unit 35 a of the piezo actuator 35. Have. A pair of first longitudinally extending portions 44b extending in the pulling direction is connected to the force point portion 44a. A pair of first laterally extending portions 44c extending so as to be separated from each other in a direction orthogonal to the tensile direction is connected to each of the first vertically extending portions 44b. The first laterally extending portion 44c is disposed with a slight gap in the fixed wall portion 32d. A first fulcrum portion 44d connected to the fixed wall portion 32d in a bridge shape is provided near the force point portion 44a of the first laterally extending portion 44c.

  A pair of second longitudinally extending portions 44e extending in the direction opposite to the tensile direction (upward in FIG. 11) is connected to the end portion on the separation side of each first laterally extending portion 44c. A pair of second laterally extending portions 44f extending so as to be close to each other in a direction orthogonal to the tensile direction is connected to each second vertically extending portion 44e. The second laterally extending portion 44f is disposed with a slight gap in the fixed wall portion 32d, and the fixed wall portion 32d and the bridge are located near the second longitudinally extending portion 44e of the second laterally extending portion 44f. 44g of 2nd fulcrum parts connected in a shape are provided. An end portion on the close side of each second laterally extending portion 44 f is connected to the load cell fixing portion 46 via the action point portion 45. That is, the action point portion 45 serves as an output portion of the displacement amplifying portion 44 and relays power transmission from the displacement amplifying portion 44 to the load cell fixing portion 46. Moreover, the displacement amplification part 44 has two pairs of fulcrum parts 44d and 44g, and has a long shape in a direction orthogonal to the tensile direction. The load cell fixing portion 46 is connected to the housing body portion 32a so that the front and rear thereof can be relatively displaced by connecting spring portions 47 and 48. The connection spring portions 47 and 48 are formed in a meandering shape in plan view, and can be expanded and contracted in the tension direction. Further, in the power transmission mechanism 36, in the first longitudinally extending portion 44b, the first fulcrum portion 44d, the second longitudinally extending portion 44e, the second fulcrum portion 44g, and the action point portion 45, notches are provided in adjacent portions. Thus, displacement in a direction deviating from the tensile direction is allowed.

  As described above, the power transmission mechanism 36 is configured to transmit power through a pair of power transmission paths sandwiching the tension direction, and the pair of power transmission paths sandwich the central axis of the tension load transmission member 34 in the tension direction. It is formed symmetrically. That is, since the power transmission mechanism 36 is symmetrical with respect to the central axis in the tensile direction of the tensile load transmission member 34, the first vertical extension 44b, the first fulcrum 44d, and the second vertical extension 44e are assumed. Even if a displacement deviating from the tension direction occurs at each of the second fulcrum part 44g and the action point part 45, their combined force is configured to automatically match the tension direction.

  Next, the operation of the power transmission mechanism 36 will be described. In addition, the length of the arrow shown in FIG. 11 means the magnitude of the displacement. As shown in FIG. 11, first, the output part 35 a of the piezo actuator 35 presses the force point part 44 a of the displacement amplifying part 44 in the pulling direction. Then, the pair of first longitudinally extending portions 44b are displaced along the pulling direction, and the pulling of the end portions on the separation side of the respective first laterally extending portions 44c is performed based on the lever principle using the first fulcrum portion 44d as a fulcrum. The amount of displacement in the direction is amplified, and the second vertically extending portion 44e connected thereto is displaced in the direction opposite to the tensile direction. And the edge part of the separation side of the 2nd lateral extension part 44f displaces in the direction opposite to a tension | pulling direction, The proximity | contact side of each 2nd lateral extension part 44e by the lever principle which made the 2nd fulcrum part 44g a fulcrum The amount of displacement in the pulling direction at the end of the plate is further amplified, the action point portion 45 connected thereto is displaced in the pulling direction, and the load cell fixing portion 46 is largely displaced in the pulling direction. That is, even when the piezoelectric actuator 35 having a small deformation amount of several tens of μm is used, the displacement amount can be amplified up to about four times by the displacement amplification unit 44.

[Assembly of tensile test equipment]
Next, in order to understand the structure of the tensile test apparatus 20, its assembly will be briefly described. 12 to 16 are perspective views for explaining the first to fifth steps of assembling the tensile test apparatus 20. First, as shown in FIG. 12, the base 31 is placed on a work table (not shown). The base 31 includes a flat plate portion 31a and a rectangular tube portion 31d that protrudes upward at the central portion of the flat plate portion 31a. The flat plate portion 31a is provided with screw holes 31b for fixing the housing 32 and the like at required portions, and screw holes 31c for attachment to a work table (not shown) are provided at four corners. Yes. The rectangular cylinder portion 31d is provided with attachment holes 31e for attaching the piezo actuators 35 to the four wall surfaces thereof.

  Next, as shown in FIG. 13, four piezo actuators 35 are attached to the respective attachment holes 31 e of the base 31 via fixing jigs 35 b. Next, as shown in FIG. 14, the housing 32 is attached to the base 31 from above. In the central portion of the housing body 32 a of the housing 32, a mounting table recess 32 c for accommodating and mounting the mounting table 33, a load cell recess 32 g for fixing the load cell 37, and a differential transformer for fixing the differential transformer fixture 39. A fixing tool recess 32h is provided. An opening 32f is formed at the center of the installation table recess 32c. A continuous opening 32j is formed between the load cell recess 32g and the differential transformer fixture recess 32h. At the four corners of the side wall of the housing 32, wiring inlets 32b are provided. Further, the housing 32 is provided with a screw hole 32k communicating with the screw hole 31b of the base 31.

  Next, as shown in FIG. 15, the load cell 37 is fixed to the load cell recess 32g, and the lower fixing member 41 of the differential transformer fixture 39 is fixed to the differential transformer fixture recess 32h. Next, as shown in FIG. 16, the installation table 33 is accommodated in the installation table recess 32 c, the tensile load transmission member 34 is fixed to the load detection unit (not shown) on the upper surface side of the load cell 37, and the tensile load transmission is performed. The small width portion 34 c of the member 34 is accommodated in the constant width groove portion 33 b of the installation base 33. Further, the differential transformer 38 connected to the tensile load transmission member 34 is disposed on the lower fixing member 41, and the upper fixing member 42 is fixed to the lower fixing member 41. Fixed against. Finally, as shown in FIG. 8, the housing 32 is fixed to the base 31 with screws 50 and completed.

[Tensile test method]
Next, a method for performing a tensile test on the thin film test piece structure 1 using the tensile test apparatus 20 will be described. First, the thin film test piece structure 1 (see FIG. 1) is installed on the installation base 33 (see FIG. 9) of the tensile test apparatus 20, and the tensile test apparatus 20 is engaged with the engagement hole 5 of the thin film test piece structure 1. The protrusion 34b is inserted. At this time, the thin film test piece structure 1 is supported by the installation surface 33 d of the installation table 33, and the base portion 34 a of the tensile load transmitting member 34 is not in contact with the thin film test piece structure 1. In this state, by driving the piezo actuator 35 (see FIG. 11), the output portion 35a presses the force point portion 44a of the displacement amplifying portion 44 of the power transmission mechanism 36, and the force point portion 44a is displaced in the pulling direction. Then, the displacement amplification unit 44 amplifies the displacement of the action point part 45 so as to be larger than the displacement of the force point part 44a. Then, the load cell fixing portion 46 (see FIG. 11) that moves integrally with the action point portion 45 displaces the tensile load transmitting member 34 in the tension direction via the load cell 37. As a result, the thin film test piece 2 engaged with the engagement protrusion 5b of the tensile load transmission member 34 through the engagement hole 5 is pulled together with the support member 3 (see FIG. 1). At that time, a tensile load which is a reaction force from the thin film test piece 2 and the support member 3 is detected by the load cell 37 (see FIG. 11), and displacement of the thin film test piece 2 and the support member 3 is detected by the differential transformer 38 (see FIG. 11).

  In the biaxial tensile test, the central part of the test piece should not move regardless of the magnitude of the tensile load. However, according to this tensile test apparatus 20, four sets of the piezoelectric actuator 35, the load cell 37, and the differential transformer 38 are provided. Therefore, the tensile test can be performed while monitoring the tensile load and the displacement, and the position of the central portion of the test target portion 2a of the thin film test piece 2 can be kept constant. In addition, the thin film test piece 2 photographed by the CCD camera 26 (see FIG. 7) during the tensile test is image-analyzed by the computer 25 so that the central portion of the test target portion 2a of the thin film test piece 2 is analyzed. The position may be kept constant.

  Then, the first tensile test is performed until the test target portion 2 a of the thin film test piece 2 is broken, and the tensile load and displacement data at that time are stored in the computer 25. Next, a second tensile test is performed under the same conditions as the first while the thin film test piece 2 is broken, and the tensile load and displacement data at that time are stored in the computer 25.

  FIG. 17 is a graph illustrating a method for calculating the relationship between the tensile load and the displacement with respect to the thin film test piece 2. As shown in FIG. 17, the first tensile load and displacement data before the fracture of the thin film test piece 2 is data relating to the combination of the thin film test piece 2 and the support member 3, and the elastic connection portion 3 d, The effect of 3e is included. The data of the second tensile load and displacement after the thin film test piece 2 is ruptured are data related to the support member 3 only. And the tension | tensile_strength only about the thin film test piece 2 is each subtracted from the tensile load and displacement of the 2nd time after the fracture | rupture of the thin film test piece 2 from the first tensile load and displacement before the thin film test piece 2 fracture. Load and displacement data (shaded area in FIG. 17) is obtained. In this way, the thin film test piece 2 can be stably pulled in a state where the support member 3 is joined, and the thin film test piece 2 alone is excluded from the influence of the support member 3 after the thin film test piece 2 is broken. Characteristics can be obtained.

  FIG. 18 is a graph of the first example showing the relationship between the tensile load and the displacement when the thin film test piece structure 1 is subjected to a biaxial tensile test using the tensile test apparatus 20. FIG. 19 is a graph of the second example showing the relationship between the tensile load and the displacement when the thin film test piece structure 1 is subjected to a biaxial tensile test using the tensile test apparatus 20. 18 and 19, the white circle plots are the tensile test results before the thin film test piece 2 made of aluminum, and the solid line is the tensile test results after the thin film test piece 2 is broken. In FIGS. 18 and 20, CH-1 and CH-3 show the tensile test results in the X direction, and CH-2 and CH-4 show the tensile test results in the Y direction.

In FIG. 18, the output of the piezo actuator 35 is the same at 0.093 [N] from CH-1 to CH-4, and the values of tensile load and displacement are all the same. In FIG. 19, the output of the piezo actuator 35 is 0.086 [N] for CH-1 and CH-3, and 0.025 [N] for CH-2 and CH-4. In the graph of FIG. 18, the output results are the same from CH-1 to CH-4, and in the graph of FIG. 19, the output results of CH-1 and CH-3 and the outputs of CH-2 and CH-4. The result is different.
It can be seen from these graphs that the state of the tensile load and displacement in each direction under the biaxial tension condition can be accurately grasped.

  FIG. 20 is a graph showing the yield stress when the thin film test piece structure 1 is subjected to a biaxial tensile test using the tensile test apparatus 20. In addition, the plot on the X-axis and the plot on the Y-axis in the graph of FIG. 20 mean the yield stress in a uniaxial tensile test. As shown in FIG. 20, according to the biaxial tensile test, values deviating from the dotted line obtained by extending the plots on the X axis and Y axis obtained from the uniaxial tensile test in the XY direction are obtained. This is a knowledge obtained for the first time by conducting a biaxial tensile test, and the effectiveness of the present invention for thin film material evaluation is recognized.

[Effect of thin film specimen structure]
According to the thin film test piece structure 1 of the present embodiment, the test piece support portion 3a of the support member 3 is joined to the load transmitting portion 2b of the thin film test piece 2, and the test piece support portion 3a is elastically connected. Since it is connected to the frame part 3c by the parts 3d and 3e, the thin film test piece 2 is hardly twisted and is stably held in a correct position and posture. Therefore, it is possible to perform a tensile test with high accuracy using a test piece made of a thin film material. In addition, since the thin film test piece 2 is stably held by the support member 3, the thin film test piece 2 can be easily handled, and breakage during handling of the thin film test piece 2 can be prevented.

  Further, since the elastic connecting portions 3d and 3e are bent so that the test piece support portion 3a is displaced in the tensile direction with respect to the frame portion 3c, the relative displacement in a direction different from the tensile direction is suppressed to suppress the thin film test piece 2. It is possible to flexibly allow relative displacement of the test piece support portion with respect to the frame portion while preventing twisting of the test piece. Further, if the engagement protrusion 34 b on the tensile test device 20 side is inserted into the engagement hole 5, a tensile force can be applied to the thin film test piece 2 without grasping the thin film test piece 2. It is possible to prevent twisting of the sheet.

  Further, since the silicon oxide film 7 is interposed between the single crystal silicon plate 6 constituting the support member 3 and the thin film test piece 2 made of metal, the metal constituting the thin film test piece 2 is made of single crystal silicon. It is possible to prevent the physical properties from being changed by diffusing inside the plate 6. Further, since the dummy thin film layer 4 is formed in the vicinity of the test target portion 2a of the frame portion 3c and the mark 4a facing the mark 2c1 of the thin film test piece 2 is formed on the outer edge thereof, the marks 2c1, 4a The displacement state of the thin film test piece 2 can be visually grasped by recognizing the position on the photographed image.

[Effects of tensile testing equipment]
According to the tensile test apparatus 20 of the present embodiment, the frame portion 3c of the support member 3 of the thin film test piece structure 1 is installed on the installation base 33, and the biaxial tensile force is applied to the load transmitting portion 2b of the thin film test piece structure 1. It is possible to accurately measure the tensile load and displacement. In addition, the base 34a of the tensile load transmitting member 34 is the thin film test piece structure in a state where the engagement protrusion 34b is inserted into the engagement hole 5 of the thin film test piece structure 1 placed on the installation surface 33d of the installation table 33. 1, even if the flatness of the tensile load transmission member 34 is not sufficient, the thin film test piece structure 1 can be maintained in the correct position and posture. Further, since the installation table 33 is an integral product, it is possible to save the trouble of adjusting the flatness of the installation surface 33d when setting the tensile test apparatus 20 at the test place.

  Further, since the piezo actuator 35 is disposed below the tensile load transmission member 34 in the housing 32, the entire apparatus is made compact compared to a case where the piezoelectric actuator 35 is arranged in series in the tensile direction with respect to the tensile load transmission member 34. be able to. Further, since the displacement generated by the piezo actuator 35 is amplified by the displacement amplifying unit 44 of the power transmission mechanism 36, the tensile load transmission member 34 can be greatly displaced even if the displacement generated by the piezo actuator 35 is small. Become. Further, the displacement amplifying part 44 has a plurality of fulcrum parts 44d, 44g and has a shape that is long in the direction orthogonal to the tensile direction, so that the power transmission mechanism 36 in the direction in which the tensile load transmission member 34 moves. The space occupied by can be reduced, and the entire apparatus can be made compact.

  Further, since the pair of power transmission paths of the power transmission mechanism 36 are formed symmetrically with respect to the central axis in the tensile direction of the tensile load transmission member 34, the displacement directions of the individual power transmission paths are completely in the axial direction. Even if they do not coincide with each other, the direction of the resultant force by both power transmission paths can coincide with the axial direction. Furthermore, since the power transmission mechanism 36 is connected to the housing body 32a via the connection springs 47 and 48 so as to be relatively displaceable, and is integrally formed as a part of the housing 32, the number of parts can be reduced. .

  As described above, the thin film specimen structure, the manufacturing method, the tensile test method, and the tensile test apparatus according to the present invention are widely applied to various fields such as a micromachine and a microdevice that can exhibit the significance of the effects described above. be able to.

It is a perspective view which shows the thin film test piece structure which concerns on embodiment of this invention. It is a top view of the thin film test piece structure shown in FIG. It is the III-III sectional view taken on the line of FIG. It is an expansion perspective view showing the elastic connection part of the thin film test piece structure shown in FIG. 1, and its vicinity. It is an enlarged plan view showing the test object part and its vicinity of the thin film test piece structure shown in FIG. (A)-(f) is sectional drawing explaining the manufacturing procedure of a thin film test piece structure. 1 is an overall view schematically showing a tensile test system having a tensile test apparatus according to an embodiment of the present invention. 1 is a perspective view showing a tensile test apparatus according to an embodiment of the present invention. It is an expansion perspective view showing the installation stand of the tensile test apparatus shown in FIG. 8, and its vicinity. It is an expansion perspective view showing the power transmission mechanism of the tension test apparatus shown in FIG. 8, and its vicinity. It is an enlarged plan view showing the power transmission mechanism of the tensile test apparatus shown in FIG. 8 and its vicinity. It is a perspective view explaining the 1st process of the assembly of the tensile test apparatus shown in FIG. It is a perspective view explaining the 2nd process of the assembly of the tensile test apparatus shown in FIG. It is a perspective view explaining the 3rd process of the assembly of the tensile test apparatus shown in FIG. It is a perspective view explaining the 4th process of the assembly of the tensile test apparatus shown in FIG. It is a perspective view explaining the 5th process of the assembly of the tensile test apparatus shown in FIG. It is a graph explaining the method of calculating the relationship between the tensile load and displacement regarding a thin film test piece. It is a graph of 1st Example which shows the relationship between the tensile load at the time of carrying out the biaxial tension test of the thin film test piece structure of FIG. 1 with the tension test apparatus of FIG. It is a graph of 2nd Example which shows the relationship between the tensile load at the time of carrying out the biaxial tension test of the thin film test piece structure of FIG. 1 with the tension test apparatus of FIG. It is a graph which shows the yield stress at the time of carrying out the biaxial tension test of the thin film test piece structure of FIG. 1 with the tension test apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin film test piece structure 2 Thin film test piece 2a Test object part 2b Load transmission part 2c1, 2d1, 4a Mark 3 Support member 3a Test piece support part 3c Frame part 3d, 3e Elastic connection part (connection part)
DESCRIPTION OF SYMBOLS 5 Engagement hole 6 Single crystal silicon plate 7 Silicon oxide film 20 Tensile test device 32 Housing 32a Housing main body 33 Installation base 33d Installation surface 34 Tensile load transmission member 34a Base 34b Engagement protrusion 35 Piezo actuator (drive device)
36 Power transmission mechanism 37 Load cell (load measuring device)
38 Differential transformer (displacement measuring device)
44 Displacement amplification part 44a Force point part 44d, 44g Support point part 45 Action point part

Claims (15)

A thin film specimen structure used for a tensile test,
A thin film test piece provided with a test object part and a load transmission part continuous thereto; and
A support member that supports at least a portion of the thin film test piece excluding the test target portion;
The support member includes a test piece support unit joined to the load transmitting unit, a frame unit arranged around the thin film test unit, and the test piece support unit in a tensile direction with respect to the frame unit. A thin-film test piece structure having a connecting portion connected so as to be relatively displaceable.   The thin film test piece structure according to claim 1, wherein the load transmitting portion extends in a biaxial direction from the test target portion.   The thin film test piece structure according to claim 1 or 2, wherein the connecting portion is provided symmetrically on both sides of the load transmitting portion with respect to the axial direction.   The thin film test piece structure according to any one of claims 1 to 3, wherein the connecting portion includes an elastic connecting portion that elastically connects the test piece support portion to the frame portion.   The thin film test piece according to claim 4, wherein the elastic connection part is formed of a spring linear body that is integrally formed of the same material as the test piece support part and the frame part and is formed in a distorted shape in plan view. Structure.   The thin film test piece structure according to claim 5, wherein the spring linear body has a thickness in a direction orthogonal to the plane larger than a width in a plane direction of the thin film test piece and the support member.   The thin-film test piece structure according to any one of claims 1 to 6, wherein an engagement hole is formed in the load transmitting portion and the test piece support portion.   The layer which forms the same plane as the said thin film test piece in the said test object part vicinity of the said frame part is provided, and the mark which opposes the said thin film test piece is formed in the outer edge of this layer. The thin film test piece structure according to any one of 1 to 7. A method of manufacturing a thin film specimen structure used for a tensile test,
Forming a thin film test piece provided with a test target portion and a load transmission portion continuous therewith on one surface side of an unetched substrate made of a corrosive material;
A step of performing anticorrosion treatment of a required shape on at least a part of the other side of the unetched substrate in plan view excluding the test target part;
Etching the unetched substrate from the other surface side, a test piece support joined to the load transmitting part, a frame part arranged around the thin film test piece in plan view, Forming a support member having a connecting portion that connects the test piece support portion to the frame portion so as to be relatively displaceable in a tensile direction. . A method for tensile testing the thin film specimen structure according to any one of claims 1 to 8,
Applying a tensile force to the load transmitting part and the test piece support part of the thin film test piece structure, and measuring the first tensile load and displacement,
After breaking the test object part of the thin film test piece structure, a tensile force is again applied to the load transmitting part and the test piece support part under the same conditions as the first time, and a second tensile load and Measuring displacement,
A tensile test method characterized by subtracting the tensile load and displacement measured at the second time from the tensile load and displacement measured at the first time, respectively. An apparatus for tensile testing the thin film specimen structure according to any one of claims 1 to 8,
An installation base on which the frame part of the support member of the thin film test piece structure is installed;
A tensile load transmitting member for transmitting a tensile load to the load transmitting portion of the thin film test piece structure;
A driving device for generating power for moving the tensile load transmitting member;
A power transmission mechanism for transmitting power from the driving device to the tensile load transmission member;
A load measuring device for measuring a load applied to the tensile load transmitting member;
A tensile test apparatus comprising: a displacement measuring device that measures the displacement of the tensile load transmitting member.   The tensile test apparatus according to claim 11, wherein the tensile load transmitting member is configured to apply a biaxial tensile force to the thin film specimen structure. The tensile load transmission member has a base and an engagement protrusion that protrudes from the base and is inserted into the engagement hole of the thin-film test piece structure,
The installation table is an integrated product having a plurality of flat installation surfaces,
The base of the tensile load transmission member is located below a plane including the installation surface,
The tensile test apparatus according to claim 11 or 12, wherein the engagement protrusion of the tensile load transmission member protrudes upward from a plane including the installation surface. The tensile load transmission member extends in a direction away from the installation base,
The tensile testing device according to any one of claims 11 to 13, wherein the driving device is disposed below the tensile load transmission member and connected to the tensile load transmission member via the power transmission mechanism.   The power transmission mechanism includes a power point at which a driving force from the driving device acts, a point at which the driving force is transmitted to the tensile load transmission member, and a displacement at the point of action according to the principle of leverage than a displacement at the power point. The tensile testing device according to any one of claims 12 to 14, further comprising a fulcrum for increasing.

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