JPH09138191A - Method and apparatus for determining reference position in micro indentation hardness tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a micro indentation hardness tester in which the reference position is set automatically for a presser and a contactor. SOLUTION: Electrode plates are applied to the opposing faces of a contact lever 4 and a presser lever 2 to form first and second capacitors. A CPU 31 receives the capacitance from each capacitor and produces a control current for elongating/contracting a PZT (laminated piezoelectric actuator) 30. Consequently, the contact lever 4 is turned about a shaft 5 such that the capacitance is equalized for both capacitors thus realizing automatic setting of reference position for the presser and a contactor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro indentation hardness tester, and more particularly to a method and device for determining a reference position of the hardness tester.

[0002]

2. Description of the Related Art Conventionally, a hardness tester with a minute load with an indentation load of 1 gf or less has been used for a material test of a surface layer of a film-formed product in relation to semiconductors. As such a testing machine, one described in JP-A-63-223539 is known, which is shown in FIG.
Describing with reference numeral 10, reference numeral 1 indicates an indenter, and the indenter 1 is fixedly held to the tip of the indenter lever 2.

Reference numeral 3 denotes a contactor, which is fixedly held at the tip of a contactor lever 4, and the indenter lever 2 and the contactor lever 4 are on the same axis of the shaft 5. It is pivotally supported by an indenter lever cross spring 6 and a contactor lever spring 7. The indenter 1 and the contactor 3 are the tip of the indenter lever 2 and the contactor lever 4 on the circular arc centered on the cross springs 6 and 7 of the indenter lever 2 and the contactor lever 4, respectively.
It is adapted to reciprocate along an axis B perpendicular to the surface of 40, and the contactor 3 reciprocates around the indenter 1.

As shown in detail in FIGS. 4 and 5, the cross springs 6 and 7 have an arcuate fixing portion 8 fixed to a base 10, and an arcuate swinging portion 9 is provided opposite to the fixing portion 8. . Fixed part 8
The rocking portion 9 and the swinging portion 9 are connected by a spring body 11, and the two spring bodies 11 are attached so as to form a cross shape in the side view of FIG. Further, as shown in FIG. 5, the spring body 11 is composed of two springs and connects the fixed portion 8 and the swinging portion 9, but the two springs do not contact each other and operate independently. The swinging portion 9 is fixed to the indenter lever 2 and the contactor lever 4, the intersection of the spring body 11 in the side view is on the axis 5 of the cross springs 6 and 7, and the axes of the cross springs 6 and 7 are the indenters. It is configured to be on the central axis C of the lever 2 and the contactor lever 4.

The indenter lever 2 and the contact lever 4 are statically balanced with the cross springs 6 and 7 as intersections. Since the indenter lever 2 and the contactor lever 4 press the indenter and the contactor against the sample as described later, it is preferable that the rigidity is high, but the influence of the swing is reduced and the moving speed of the indenter 1 is changed. Therefore, it is necessary to be lightweight and to have a small moment of inertia about the cross springs 6 and 7, which results in a lightweight and highly rigid structure.

As shown in FIG. 6, one cross spring 6 of the indenter lever 2 is attached to the cross springs 6 and 7 of the indenter lever 2 and the contact lever 4, and the cross spring 7 of the contact lever 4 is attached.
Are attached to both sides of the cross spring 6 of the indenter lever 2 as a center. In this way, the indenter lever 2 is sandwiched between the two contactor levers 4 which are joined and integrated at both ends, and the indenter lever 2 and the contactor lever 4 do not contact but move independently. It is like this. The tip of the contactor lever 4 holds the contactor 3 so as to surround the indenter lever 2, and the indenter 1 passes through a hole formed in the contactor 3 and moves up and down. Further, load devices 21 and 24 for driving the indenter lever 2 and the contactor lever 4 are attached to the other ends of the indenter lever 2 and the contactor lever 4.

As shown in FIG. 7 for details of the tips of the indenter lever 2 and the contact lever 4, the indenter 1 is fixed to the lower surface of the tip of the indenter lever 2, and the upper surface of the tip of the indenter lever 2 is A letter-shaped electric insulator 12 is fixed. As shown in FIG. 8, the tip of the contact lever 4 has a contact 3 fixed to the lower surface of the tip of the contact lever 4 so as to concentrically surround the indenter 1. Reciprocate through 3. An electric insulating plate 13 is fixed to the upper surface of the tip of the contact lever 4, and the electric insulating plate 13 is fitted into the U-shape of the electric insulator 12 of the indenter lever 2. An electrode plate of 1 cm 2 or more is attached to the U-shaped inner surface of the electric insulator 12 and the outer surfaces of the electric insulating plate 13 on the surfaces of the horizontal surfaces facing each other. Electrode plates 14 and 16 are fixed to the electric insulator 12 fixed to the indenter lever 2, and electrode plates 16 and 17 are fixed to the electric insulating plate 13 fixed to the contact lever 4, and electrode plates 14, 15 and 15, 17 are fixed. At the reference position of the indenter 1 and the contactor 3, both face each other with a minute interval of about 50 μm.

The electrode plates 14, 16 and 15, 17 form an electric capacitor, and the relative displacement between the indenter 1 and the contactor 3 is the first capacitor 18 formed by the electrode plates 14, 16 and the electrode plate 15. , 17 in proportion to the difference in electric capacity between the second capacitor 19 and the second capacitor 19. Therefore, the relative change between the indenter 1 and the contactor 3 can be obtained by using the known oscillator and amplifier for detecting the capacitance change.
Is configured.

A load device 21 is mounted on the opposite side of the indenter 1 with the cross spring 6 of the indenter lever 2 as the center.
Reference numeral 21 is a drive coil 22 and a permanent magnet 23.
When the current is applied to the indenter 22, the indenter lever 2 drives the indenter 1 with the cross spring 6 as a fulcrum, and applies a predetermined load proportional to the current of the drive coil 22 to the indenter 1. A load device 24 is also mounted on the opposite side of the contact lever 4 from the cross spring 7, and the load device 24 is composed of a drive coil 25 and a permanent magnet 26. By passing an electric current through the drive coil 25, the contact lever 4 crosses. The contactor 3 is driven using the spring 7 as a fulcrum, and a predetermined load proportional to the current of the drive coil 25 is applied to the contactor 3.

However, the driving force provided by the drive coil 22 is partially consumed as a spring force for bending the spring of the cross spring 6 when the indenter lever 2 tilts, and the driving force for driving the indenter 1 is Since the spring force of the cross spring 6 is subtracted from the force given by the current of, the spring force of the cross spring is calculated, and this spring force is subtracted from the driving force to determine the force with which the indenter 1 presses the sample 40. Need to ask. This uses the output of the displacement meter 20 and is as follows.
That is, after the contactor 3 is pressed against the sample 40, the driving force of the indenter 1 is increased until the displacement gauge 20 becomes zero, and the driving force at that point is used as a reference point to verify the spring constant of the cross spring 6 and the displacement gauge. The true pressing force generated between the indenter 1 and the sample can be obtained by multiplying the output of 20 and subtracting from the driving force.

In order to carry out the measurement with this micro-region strength testing apparatus, the sample 40 is placed on the sample stage 44 including the fine movement stage 41 and placed under the microscope 43. When the fine movement table 41 is adjusted up and down to adjust the focus, the vertical position of the surface of the sample 40 becomes the vertical position just to be measured when the sample table 44 is moved right below the indenter 1 by the sample moving mechanism 45. It is like this. Further, while the sample 40 is placed at the position directly below the microscope 43, the fine movement table 41 is moved horizontally to adjust the position of the sample surface to be measured to the center of the visual field of the microscope 43. Then, when the sample table 44 is moved right below the indenter 1 by the sample moving mechanism 45, the position of the surface of the sample 40 in the center of the field of view of the microscope 43 becomes the position of contacting the tip of the indenter 1. At this time, since the indenter 1 and the contactor 3 have not been activated yet, the positions of the microscope 43 and the indenter 1 are set in advance so that the distance between the indenter 1 and the surface of the sample 40 becomes a fixed value within 1 mm. . The microscope 43 should be used not only for positioning the sample, but also for pressing the indenter 1 into the sample 40 and then moving it again below the microscope 43 by the sample moving mechanism 45 to measure the size and shape of the indentation. You can also

Next, the case where the sample 40 is pressed by the indenter 1 to perform measurement will be described. First, when a direct current is applied to the drive coil 25 of the contact lever 4, the contact lever 4 rotates about the cross spring 7 as a fulcrum, lowers the contact 3 downward, and presses the surface of the sample 40. The pressing force in this case is 0.05N
The pressure is about (Newton), and the pressing force is adjusted by changing the current flowing through the drive coil 25. Since no force is applied to the indenter lever 2 in this state, as shown in FIG. 8, the electrical insulating plate 13 fixed to the contactor lever 4 together with the contactor lever 4 is lowered and the electrical insulating plate 13 is moved downward. Electrodes
16 and electrode 14 of electrical insulator 12 fixed to indenter lever 2
And the indenter lever 2 are pushed down together with the contactor lever 4.

Next, the indenter 1 is driven by the indenter lever 2. Since the force for driving the indenter 1 must be precisely controlled, as described above, the displacement gauge of the indenter 1 is measured.
20 compensates the spring force of the cross spring 6. Ie figure
As shown in FIG. 10, the drive signal 50 of the indenter lever 2 is amplified by the drive amplifier 51 and becomes a current value 52, which is the drive coil 22.
The difference between the current value 52 and the current value 53 corresponding to the spring force of the cross spring 6 detected by the displacement meter 20 is obtained by the comparator 34, and only the load with which the indenter 1 presses the sample 40 is driven. Is taken out as the signal 35.

[0014]

By the way, in the indentation hardness tester, the indenter 1 and the contactor 3 are tested prior to the test.
It is necessary to set the reference positions for and, and in the above-mentioned conventional device, the reference position is set as follows. First, a direct current is applied to the drive coil 22 of the indenter lever 2, and the indenter lever 2 is rotated about the cross spring 6 as a fulcrum to apply a force to lower the indenter 1 downward. Then the electrode plate 1
The objects that 4 and 16 were in contact with are separated. So indenter displacement meter 2
First capacitor 18 formed by 0 electrode plates 14, 16
The drive current value 32 is adjusted while observing the output of the indenter displacement meter 20 so that the electric capacities of the second capacitor 19 formed by the electrode plates 15 and 17 become equal. As a result, the distance between the electrode plates of the first and second capacitors 18 and 19 is both 50 μm.
This position becomes m and becomes the reference position for the indenter 1 and the contactor 3.

By the way, the reference position is set by driving the driving coil 22 while observing the output of the indenter displacement gauge 20 as described above so that the electric capacitances of the first capacitor and the second capacitor become equal. Since this is a fine adjustment work of adjusting the value of the current value 32, there is a problem that the operation requires skill and a long time is required for the adjustment. It is an object of the present invention to provide a method and apparatus for determining a reference position in a micro push-in type hardness tester, which solves the above problems.

[0016]

Therefore, in the method for determining the reference position in the micro push-in hardness tester of the present invention, the indenter is provided at the tip end while being rotatably supported by the shaft with respect to the machine frame. An indenter lever, a contact lever rotatably supported by the shaft with respect to the machine frame, and a tip provided with a contact having a central through hole through which the indenter can penetrate, and the indenter lever A U-shaped electrical insulator provided at the tip of the contact lever, an electrical insulating plate attached to the tip of the contact lever so as to be fitted into the U-shape of the U-shaped electrical insulator, and The indenter of the micro indentation type hardness tester provided with the first and second capacitors respectively constituted by electrode plates respectively attached to two U-shaped electric insulators and two electric insulating plates facing each other. And the base of the contact Position upon setting the, and the capacitance of the first and second capacitors is rotated the contact lever to equal a means of solving the problems.

The reference position determining device in the micro indentation hardness tester of the present invention includes an indenter lever rotatably supported by a shaft with respect to the machine frame and having an indenter at its tip, and the shaft. And a contact lever that is rotatably supported by the machine frame and has a contact having a central through hole through which the indenter can penetrate, and a coil provided at the tip of the indenter. A U-shaped electric insulator, an electric insulating plate attached to the tip of the contact lever so as to be inserted into the U-shaped electric insulator, and the U-shaped electric insulator. A micro indentation type hardness tester equipped with first and second capacitors each composed of an electrode plate attached to an electrically insulating plate at two locations opposed to each other, and between the contact and the machine frame. PZ
A problem is solved by providing a current control circuit for supplying a PZT control current through T to expand and contract the PZT and inputting each electric capacitance of the first and second capacitors to the current control circuit. Is used as a means.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the drawings, a reference position determining method and device in a micro-pushing hardness tester as one embodiment of the present invention will be described below. FIG. 1 is a side view showing the main parts thereof, and FIG. 2 is an enlarged view of arrow A in FIG. The same reference numerals as those in FIGS. 3 to 10 in FIGS. 1 and 2 denote the same members.

The micro indentation hardness tester of this embodiment also has the same construction as the conventional one described above. That is, an indenter lever 2 holding an indenter 1 and a contactor lever 4 holding a contactor 3 are provided.
Is fixed to the lower surface of the tip of the indenter lever 2, and a U-shaped electric insulator 12 is fixed to the upper surface of the tip of the indenter lever 2. As shown in FIG. 8, the tip of the contact lever 4 has a contact 3 fixed to the lower surface of the tip of the contact lever 4 so as to concentrically surround the indenter 1. Reciprocate through 3. An electric insulating plate 13 is fixed to the upper surface of the tip of the contact lever 4, and the electric insulating plate 13 is attached to the indenter lever 2.
The electric insulator 12 is fitted into the U-shape. An electrode plate of 1 square centimeter or more is attached on the surfaces of the U-shaped inner surface of the electric insulator 12 and the outer surface of the electric insulating plate 13 which are opposite to each other in a horizontal plane. The electric insulator 12 fixed to the indenter lever 2 has electrode plates 14 and 15
However, the electrical insulation plate 13 fixed to the contact lever 4 has an electrode plate.
16 and 17 are fixed, and electrode plates 14, 16 and 15, 17 are indenter 1
At the reference position between the contactor 3 and the contactor 3, both face each other with a minute interval of 50 μm. The electrode plates 14, 16 and 15, 17 form an electric capacitor, and the relative displacement between the indenter 1 and the contactor 3 is caused by the first capacitor 18 formed by the electrode plates 14, 16 and the electrode plates 15, 17. It is compared with the difference in electric capacity between the formed second capacitor 19. Therefore, it is possible to take out the relative displacement between the indenter 1 and the contactor 3 by using the known oscillator and amplifier for detecting the capacitance change.
20 are configured. Since the indenter displacement gauge 20 configured in this way detects the indenter 1 whose displacement needs to be measured at the position closest thereto, it is affected by the rigidity of the indenter lever 2 and other mechanical errors. It is also excellent in that it is difficult.

Further, a supporting device for reciprocatingly supporting the indenter 1 and the contactor 3 along the axis perpendicular to the sample (surface) 40 by rotating both levers (a cross on the axis 5 in the conventional apparatus). There are also provided an indenter lever load device 21, a contact lever load device 24, and the like for rotating the springs 6, 13), the indenter lever 2 and the contactor lever 4, and then press-fitting the indenter 1 into the sample 40. Then, in order to set the reference positions of the indenter 1 and the contactor 3, the following means are added. That is, as shown in FIG. 1, a PZT (multilayer piezoelectric actuator) 30 is interposed between the contact lever 4 and the machine frame 10 in a position close to the shaft 5, and a CPU 31 that gives a control current to the PZT 30. , PZ consisting of A / D converter 32 and amplifier 33
The T controller 34 is connected.

The electric capacities of the first capacitor 18 and the second capacitor 19 are input to the CPU 31, and a control current is supplied to the PZT 30 so that the electric capacities of both capacitors become equal. The PZT 30 receives the control current and expands and contracts to rotate the contact lever 4 around the shaft 5,
The contact lever 4 is moved to the position where the dimensions d ₁ and d ₂ between the tip of the contact lever 4 and the indenter lever 2, that is, the electric capacities of both capacitors are equal. Thereby, the indenter 1 and the contactor 3 can be automatically set to the reference position.

[0022]

As described in detail above, according to the reference position determining method and apparatus in the micro-indentation hardness tester of the present invention, the setting of the reference position between the indenter and the contact can be automated. It is possible to improve the ease of operation and shorten the reference position setting time.

[Brief description of the drawings]

FIG. 1 is a side view of a reference position determination device in a micro-push hardness tester as an embodiment of the present invention.

FIG. 2 is an enlarged view of an arrow A portion of FIG.

FIG. 3 is a schematic perspective view of a conventional micro indentation hardness tester.

FIG. 4 is a front view of the cross spring.

FIG. 5 is a side view of the cross spring.

FIG. 6 is a plan view of the indenter lever and the contactor lever.

FIG. 7 is an enlarged view of tips of the indenter lever and the contact lever.

8 is an enlarged view similar to FIG. 7, showing a state in which only the contact lever is operated before the tip of the indenter lever is brought into the state of FIG. 7.

FIG. 9 is a side view of a sample stage, an indenter, and a microscope.

FIG. 10 is a block diagram of a control system of the indenter lever driving device.

[Explanation of symbols]

 1 indenter 2 indenter lever 3 contactor 4 contactor lever 5 axis 6,7 cross spring 10 base 11 spring body 12 U-shaped electrical insulator 13 electrical insulating plate 14, 15, 16, 17 electrode plate 18 first capacitor 19 Second condenser 20 Indenter displacement gauge 21 Indenter lever load device 22 Driving coil 23 Permanent magnet 24 Contactor lever load device 25 Driving coil 26 Permanent magnet 30 PZT (multilayer piezoelectric actuator) 31 CPU 32 A / D converter 34 PZT Controller 40 samples

Claims (2)

[Claims] 1. An indenter lever rotatably supported by a shaft with respect to a machine frame and provided with an indenter at its tip, and a tip rotatably supported by the shaft with respect to the machine frame. A contact lever provided with a contact having a central through hole through which the indenter can penetrate, a U-shaped electrical insulator provided at the tip of the indenter lever, and a U-shaped electrical insulator An electric insulating plate attached to the tip of the contact lever so as to be fitted in a U-shape, and electrodes attached to the U-shaped electric insulator and the electric insulating plate, which are opposed to each other at two points respectively. In a micro indentation hardness tester equipped with a first and a second capacitor composed of plates, when setting the reference positions of the indenter and the contactor, the electric capacities of the first and second capacitors are made equal. To be on Characterized in that the contact lever to rotate, the reference position determination method in a micro indentation type hardness tester. 2. A micro-push-type hardness tester, wherein an indenter lever rotatably supported by a shaft with respect to the machine frame and provided with an indenter at a tip end thereof is rotated by the shaft with respect to the machine frame. A contactor lever movably supported and having a contactor having a central through hole through which the indenter can penetrate at the tip, and a U-shaped electrical insulator provided at the tip of the indenter lever, An electric insulating plate attached to the tip of the contact lever so as to fit into the U-shaped electric insulator, and the U-shaped electric insulator and the electric insulating plate facing each other. The PZT is provided between the contactor and the machine frame, and the PZT control current is applied to expand and contract the PZT. Supply current control circuit A reference position determination device in a micro-push-type hardness tester, wherein each of the electric capacities of the first and second capacitors is input to the provided current control circuit.