JPH05332908A - Tester of super fine material - Google Patents

Abstract

PURPOSE:To perform correct measurements without errors due to the temperature drift even when the environmental temperature is changed by measuring and correcting the shifting amount of an indenter for a predetermined time while a driving means is not operating and the load to a sample by the indenter is approximately zero. CONSTITUTION:When a control device 30 supplies a predetermined load current to an electromagnetic coil 13, a load transmitting lever is rotated and an indenter 16 is gradually shifted. The load current of the coil 13 is stopped before the indenter 16 comes in touch with a test piece TP. The shifting amount of the indenter 16 by the temperature drift for a predetermined time while the load by the indenter 16 to the test piece TP is zero is detected from the output of a displacement sensor 17, which is set as an error correcting factor. Then, a load current corresponding to the ordered load is fed to the coil 13 to start the indenter 16 to shift. The indenter 16 bites tone test piece after being in touch with the test piece TP. The shifting amount of the indenter 16 for a predetermined time is detected by the displacement sensor 17, and the measured value is corrected with the error correcting factor. Accordingly, the correct shifting amount is obtained at real time and stored in a memory of the control device 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrafine material testing machine for measuring the characteristics of a sample by detecting the displacement of the indenter when the indenter is pressed against a sample with a predetermined load.

[0002]

2. Description of the Related Art For example, as an ultrafine material tester for measuring the hardness of a thin film coated on a semiconductor substrate,
The one disclosed in Japanese Patent Laid-Open No. 3-89136 is known. In this type of ultra-small material testing machine, the balance-type load transmission lever is rotated by the electromagnetic force generated by supplying the load current to the electromagnetic coil, and the indenter connected to one end of the lever is moved to the sample. Press with the pressing load of
For example, the hardness of the sample is measured from the load at the time of pressing and the displacement amount of the indenter. There is also a test method in which the pressing load is removed after pressing the indenter against the sample, and the displacement amount of the indenter during unloading is measured.

[0003]

By the way, since the displacement amount of the indenter measured by such an ultrafine material testing machine is generally as small as 1 nm to 10 μm, the indenter or the like expands due to ambient temperature change. When a so-called temperature drift that contracts occurs, an error due to this temperature drift greatly affects the measurement accuracy. Therefore, conventionally, in order to minimize the ambient temperature change, the test is carried out in a temperature-controlled room, or the test is carried out after the ambient temperature has settled down to a constant value. However, when a temperature-controlled room is used, the cost and labor are correspondingly increased, and the method of waiting until the ambient temperature settles down has a disadvantage that it takes time before the test.

An object of the present invention is to provide an ultra-small material testing machine which can obtain accurate measurement results without error due to temperature drift even if ambient temperature changes.

[0005]

According to the present invention, a driving means for displacing an indenter to press the indenter against a sample with a commanded load, a displacement meter for detecting the displacement amount of the indenter, and a displacement meter for detecting the sample are detected. It is applied to an ultrafine material testing machine provided with a measuring means for obtaining the displacement amount of the indenter as a measured value. Then, when the driving means is inactive and the load of the indenter on the sample is substantially zero, the displacement amount of the indenter at a predetermined time is obtained from the output of the displacement meter, and the displacement amount is output as temperature drift information. The above-mentioned problem is solved by providing an output means for doing so.

[0006]

[Operation] When the driving means for displacing the indenter is not operated and the load on the sample by the indenter is substantially zero,
The displacement amount of the indenter in a predetermined time that is determined in advance is obtained, and this is output as temperature drift information. Based on this temperature drift information, by correcting the displacement amount (measurement value) of the indenter measured by the displacement meter when pressing the sample,
An accurate amount of displacement can be obtained without error due to temperature drift.

[0007]

【Example】

-First Embodiment- A first embodiment of the present invention will be described with reference to Figs. FIG. 1 is an overall configuration diagram of an ultrafine material testing machine according to the present invention. 2 is a sample table which is supported on the lower part of the frame 1 so as to be able to move up and down,
A stage 3 is mounted on the sample table 2 so as to be movable in the XY directions, and the sample TP is held on the stage 3. Reference numeral 10 denotes an automatic balance type electronic balance type load device provided in the frame body 1, and its structure is schematically shown in FIG.

In FIG. 2, reference numeral 11 denotes a balance-type load transmission lever which is rotatably supported around a fulcrum 12, and an electromagnetic coil 13 for driving the lever is provided above one end of the lever 11. ing. When a DC load current is supplied from the control device 30 (FIG. 1) to the electromagnetic coil 13, an electromagnetic force that pulls the lever 11 upward is generated, which causes the lever 11 to rotate counterclockwise about the fulcrum 12. To do. The other end of the lever 11 is connected to a connecting rod 15 via a leaf spring 14, and an indenter 16 for pressing the sample TP is provided at the lower end of the connecting rod 15. The indenter 16 is the lever 1
It is displaced downward with the counterclockwise rotation of 1 and is pressed by the sample TP on the stage 3. The pressing load at that time depends on the electromagnetic force of the electromagnetic coil 13, that is, the load current to the electromagnetic coil 13.

Reference numeral 17 in FIG. 1 is a differential transformer type displacement gauge for detecting the displacement amount of the connecting rod 15, that is, the indenter 16. The displacement amount of the indenter 16 which is the detected value is input to the control device 30. To be done. Reference numeral 41 is a recorder for recording the displacement amount of the indenter 16 output from the control device 30 in real time. In FIG. 1, 20 is an objective lens 21,
An optical monitor device having an eyepiece lens 22 and the like, which is used to measure a position to be tested on the surface of the sample TP and to press the indenter 16
It is used by the operator to observe the state of the depression of the sample TP attached by.

Next, the operation of the embodiment will be described with reference to the flowchart of FIG. 3 and the time chart of FIG. When performing the hardness test of the sample TP, as shown in FIG.
Is placed on the stage 3, the stage 3 is moved in the X-Y direction to position the sample TP so that it is located directly below the indenter 16, and the indenter 16 contacts the sample TP in an unloaded state. Adjust the height of the stand 2. Here, since it is difficult to bring the indenter 16 into contact with the sample TP in a completely unloaded state, there is actually a slight gap between the indenter 16 and the sample TP. When a pressing load is commanded by an operating member (not shown) at time T0 in FIG. 4, the program shown in FIG. The control device 30 first supplies a predetermined load current to the electromagnetic coil 13 in step S1. As a result, an electromagnetic force that pulls the load transmission lever 11 upward is generated, and the lever 11 moves the fulcrum 12
By rotating in the counterclockwise direction about the center, the indenter 16 is gradually displaced via the leaf spring 14 and the connecting rod 15 as shown in FIG.

After a certain period of time, the indenter 16 is still in non-contact with the sample TP, and in step S2, the electromagnetic coil 1
3 is stopped (time T1), the timer is started in step S3, a predetermined time t1 is waited in step S4, and then the timer is stopped in step S5 (time T2). Here, when there is a change in ambient temperature, the indenter 16 is displaced as shown by the temperature drift even if the supply of the load current to the electromagnetic coil 13 is stopped. In step S6, the displacement amount of the indenter 16 at the time t1 is read and stored in the variable Dd (t1) as an error correction factor (temperature drift information) due to temperature drift.

Next, in step S7, a load current corresponding to the instructed load is supplied to the electromagnetic coil 13, and the indenter 1 is again activated.
6 is started and the timer is started in step S8. The indenter 16 comes into contact with the sample TP at time T3 and moves into the sample TP while being displaced as shown in FIG. 4B. In step S9, the elapsed time t from the timer start is measured, the displacement amount of the indenter 16 at this time t is detected from the output of the displacement gauge 17, and the value is stored in the variable Dm (t) as a measured value. Since this measured value Dm (t) includes an error due to temperature drift, the error correction factor (displacement amount of the indenter due to temperature drift at time t1) Dd (t1) is removed in step S10 in order to remove this error. The true displacement amount Dr (t) is calculated by using the following equation for correction. Dr (t) = Dm (t)-(Dd (t1) / t1) · t where {(Dd (t1) / t1) · t} corresponds to an error due to temperature drift at time t. The calculated displacement amount Dr (t) is stored in the memory in the control device 30.

The processes of steps S9 and S10 are repeated until it is determined in step S11 that a predetermined time has elapsed from the start of the timer, and when the predetermined time has elapsed, the timer is stopped and the process ends in step S12. Here, at the time point T4 before the predetermined time elapses, the sample T
The pressing load on P reaches the command value, whereby the indenter 16 automatically stops. The displacement amount Dr (t) calculated and stored by the above equation is, for example, as a load-displacement curve, the recorder 4
1 is recorded, and the hardness of the sample TP is determined from the recording result.

According to the above procedure, the indenter 16 is the sample TP.
The load current to the electromagnetic coil 13 is cut off before contacting the
In this state, that is, when the load on the sample by the indenter 16 is zero, the displacement amount (displacement amount due to temperature drift) Dd (t1) of the indenter at the predetermined time t1 is detected as an error correction factor, and the sample is pressed in real time. The detected displacement Dm (t) of the indenter is {(Dd (t
Since it is corrected by 1) / t1) · t}, it is possible to obtain an accurate displacement amount Dr (t) without error due to temperature drift even if the ambient temperature changes.

In the configuration of the above embodiment, the load transmission lever 12, the electromagnetic coil 13, and the connecting rod 15 serve as driving means.
The control device 30 constitutes a measuring means and a correction value outputting means, respectively.

-Second Embodiment- Next, a second embodiment will be described with reference to FIGS.
In the first embodiment, the test method for determining the hardness of the sample TP by detecting the displacement amount of the indenter 16 when the sample is loaded has been described, but in the present embodiment, the load applied after the sample TP is loaded is changed. The characteristics of the sample TP are judged by removing the indenter and detecting the displacement of the indenter at the time of unloading. Further, in this embodiment, the error correction factor due to the temperature drift is obtained after unloading, and the measured value is corrected based on this correction factor.

FIG. 5 shows the procedure in this embodiment. In step S21, a load current is supplied to the electromagnetic coil 13 to start displacement of the indenter 16, and in step S22 a timer is started. In step S23, the displacement amount Dm1 (t) of the indenter at the elapsed time t after the timer is started.
Is detected and stored. The indenter 16 comes into contact with the sample TP at, for example, time T11 in FIG. 6, and thereafter, the indenter 16 is displaced and bites into the sample TP as shown in FIG. 6B. In step S24, the process of step S23 is repeated until the load reaches the command value, and when the load reaches the command value, the load current to the electromagnetic coil 13 is gradually decreased in step S25 to perform unloading (time point). T12). Since the sample TP tries to restore to the original state with this unloading, the indenter 16 is displaced in the direction opposite to the above.

In step S26, the indenter displacement amount Dm2
(T) is detected and stored. Step S26 is repeated until the applied load is determined to be substantially zero in step S27. When the applied load is determined to be substantially zero, it is determined that the indenter 16 is in contact with the sample TP in a substantially unloaded state, and step S28. Go to and reset the timer and restart. In step S29, the process waits until the predetermined time t1 elapses. When the predetermined time t1 elapses, the timer is stopped in step S30, and the time t is determined in step S31.
The displacement amount Dd (t1) of the indenter 16 at
Read in and proceed to step S32. Step S32
Then, the stored displacement amount Dm1 at each time point
(T) and Dm2 (t) are sequentially read, and the true displacement amounts Dr1 and Dr2 are calculated by the following equation using Dd (t1),
Remember. Dr1 (t) = Dm1 (t)-(Dd (t1) / t1) .t Dr2 (t) = Dm2 (t)-(Dd (t1) / t1) .t Calculated and stored displacement amount Dr1 (t ), Dr2 (t)
Is recorded, for example, as a load-displacement curve by the recorder 41, and the characteristics of the sample TP are determined from the recording result.

According to the above procedure, after the load is applied to the sample TP by the indenter 16, the load is removed, and the displacement amounts Dm1 (t), Dm of the indenter 16 at the time of loading and unloading.
2 (t) is measured and stored in real time. Also,
After unloading, with the indenter 16 in contact with the sample TP in a substantially unloaded state, the displacement amount (displacement amount due to temperature drift) Dd (t1) of the indenter at the predetermined time t1 is detected as an error correction factor, and (Dd ( The stored displacement amounts Dm1 (t) and Dm2 are corrected by t1) / t1) · t. Therefore, even if the ambient temperature changes, it is possible to obtain accurate displacement amounts Dr1 (t) and Dr2 (t) without an error due to temperature drift.

Here, particularly when the sample TP is heated to perform the above-described test, the temperature difference between the respective parts constituting the tester becomes large, so that the pressure between the indenter 16 and the sample stage 3 is increased when the sample is pressed. A temperature drift occurs according to the temperature difference.
Therefore, in order to remove the error due to the temperature drift, it is desirable in terms of accuracy to detect the displacement amount Dd (t1) due to the temperature drift as the error correction factor while the indenter 16 is in contact with the sample TP with no load. In the present embodiment, the above-mentioned Dd (t1) is detected in a state where the indenter 16 after removing the applied load is in contact with the sample TP without any load, and this Dd
Since the correction is performed based on (t1), even if a temperature drift corresponding to the temperature difference between the indenter 16 and the stage 3 occurs, for example, during a heating test, the accurate displacement amount Dr1 (t) , Dr2 (t) can be obtained.

In the second embodiment, when the precision is not so strict, the error correction factor Dd before the indenter 16 abuts on the sample TP as in the first embodiment.
(T1) may be detected and the correction may be performed based on this. Further, even in the test in which the amount of displacement at the time of unloading is not detected as in the first embodiment, a state in which the indenter 16 contacts the sample TP with no load by unloading is obtained, and displacement due to temperature drift at this time is obtained. The amount Dd (t1) may be detected and corrected. Further, in the above, the error correction factor Dd (t1) is detected in the control device 30 constituting the tester, the displacement amount Dm (t) of the indenter 16 at the time of pressing the sample is measured, and the Dm based on the above Dd (t1) is measured. Although the example of performing the correction of (t) is shown, the error correction factor Dd (t
1) and the displacement amount Dm (t) may be measured, and the correction may be performed by another device or manually.

[0022]

According to the present invention, when the driving means for displacing the indenter is inoperative and the load on the sample by the indenter is substantially zero, the displacement amount of the indenter at a predetermined time is set to the temperature. Since I got it as drift information,
By correcting the displacement amount (measured value) of the indenter when the sample is pressed based on the correction factor, an accurate indenter displacement amount without error due to temperature drift can be obtained even if the ambient temperature changes. Therefore, it is not necessary to use a temperature-controlled room or wait until the ambient temperature has settled down as in the conventional case, so that the cost can be reduced and the test can be performed quickly.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an ultrafine material testing machine according to the present invention.

FIG. 2 is a diagram showing a configuration of an indenter displacement mechanism.

FIG. 3 is a flowchart illustrating the operation of the first embodiment.

FIG. 4 is a time chart explaining the operation of the first embodiment.

FIG. 5 is a flowchart illustrating the operation of the second embodiment.

FIG. 6 is a time chart explaining the operation of the second embodiment.

[Explanation of symbols]

 1 frame 2 sample stage 3 stage 10 load device 11 load transmission lever 12 fulcrum 13 electromagnetic coil 14 leaf spring 15 connecting rod 16 indenter 17 displacement meter 30 controller 41 recorder TP sample

Claims (1)

[Claims] 1. A displacement means for displacing an indenter to press the indenter against a sample with a commanded load, a displacement meter for detecting the displacement amount of the indenter, and a displacement amount of the indenter detected when the sample is pressed. In an ultra-fine material testing machine equipped with a measuring means for obtaining a value, the displacement amount of the indenter in a predetermined time period when the driving means is inactive and the load on the sample by the indenter is substantially zero. Is obtained from the output of the displacement meter, and the output means outputs the displacement amount as temperature drift information.