JPH0412244A - Vibration type scratch test machine - Google Patents

Abstract

PURPOSE:To measure with high accuracy the adherence force of a thin film on the sample surface in a contact needle by detecting the displacement in the sample direction of the contact needle, and deriving a load applied to the contact needle, based thereon. CONSTITUTION:When a sample 111 is moved in the prescribed direction so that a position in the sample direction of a contact needle 110 decreases, while bringing the contact needle 110 into contact with the sample 111, while vibrating an elastic body lever 109, force loaded onto the sample surface by the contact needle 110, increases and in accordance therewith, the torsion amount of the lever 109 by frictional force between the sample surface and the contact needle 110 increases by a roughly prescribed rate against displacement of a position in the sample direction of the contact needle 110. Subsequently, when the force loaded onto the sample surface by the contact needle 110 exceeds a prescribed value, such a variation on the sample surface as a double film on the sample surface is peeled off, etc., is generated, the frictional force between the sample surface and the contact needle 110 is varied suddenly and the torsion amount of the lever 109 is also fluctuated irregularly. The force loaded onto the sample surface by the contact needle 110 is derived exactly from an elastic modulus of the lever 109 and the displacement amount in the direction being roughly vertical to the sample surface of the contact needle 110.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vibratory scratch tester for measuring the mechanical properties of a solid surface or a thin film formed on a solid surface.

[Prior Art] In order to improve the quality of thin films formed on solid surfaces by various thin film forming methods such as vacuum evaporation, sputtering, and ion blating, it is important to accurately measure the adhesion of the thin film to the substrate. This is becoming a major issue.

Conventionally, as a means of measuring the adhesion of thin films, Japanese Patent Laid-Open No. 63-
A device according to Japanese Patent No. 140939 is known. This device will be explained using FIG. 3.

This device includes a vibrating device 102, a contact needle 110 that is vibrated by the vibrating device 102, and a sample stage 112. During testing, a sample 111 is placed on the sample stage 112, and the contact needle 110 is After contacting the sample surface, the contact needle 110 is vibrated at low frequency.

During this period, a vibration output corresponding to the frictional force generated between the contact needle 110 and the sample surface is detected, and the mechanical characteristics are measured based on the magnitude, waveform, and change of this detected output. . Hereinafter, such a device will be referred to as a horizontal vibration type scratch tester.

In this testing machine, in order to determine the adhesion force of the thin film to the base material, it is essential to measure the load applied to the thin film by the contact needle 110, and the measurement accuracy of this load or the measurement accuracy of this adhesion force is determined. do.

[Problems to be Solved by the Invention] However, in such conventional techniques, there is no effective means for measuring the load of the contact needle applied to the sample, and therefore the measurement accuracy is insufficient.

In view of the problems of the prior art, an object of the present invention is to
An object of the present invention is to provide an effective means for measuring the load applied to a sample by a contact needle in a vibratory scratch tester, and to improve the measurement accuracy of the tester.

Another object of the present invention is to enable measurement of non-flat sample surfaces using such a testing machine.

[Means for Solving the Problems] In order to achieve the above object, the vibrating scratch tester of the present invention includes a contact needle that contacts a sample, a contact needle that is held, and a vertical direction perpendicular to the sample surface of the contact needle. an elastic lever member for bringing the contact needle into contact with the sample by applying a force whose displacement is variable over time to the contact needle; and an elastic lever member for moving the sample in a predetermined direction along the sample surface relative to the elastic lever member. A means of transportation for moving;
vibrating means for holding the elastic lever member and vibrating it in a direction along a sample surface perpendicular to the direction of movement by the moving means; a torsion state detection means for detecting a twist state of the elastic lever member; A displacement detection means is provided for detecting the displacement of the contact needle held by the elastic lever member in a direction substantially perpendicular to the sample surface.

The displacement detection means includes, for example, a reflecting mirror whose position is fixed with respect to the contact needle, and an optical displacement meter probe for detecting the displacement of the contact needle by receiving the reflected light from the reflecting mirror. It is equipped with an optical detection means, an installed electrode whose position is fixed with respect to the contact needle, and a capacitance measuring probe that is paired with this to accumulate electric charge and detect the capacitance. , a capacitive type can be used.

[Operation] In this configuration, when the contact needle is brought into contact with the sample while vibrating the elastic lever member and the sample is moved in a predetermined direction so that the position of the contact needle in the sample direction decreases, contact is made onto the sample surface. As the force applied by the needle increases, the amount of twisting of the elastic lever member due to the frictional force between the sample surface and the contacting needle (maximum displacement in the vibration direction during one vibration or one-way movement of the lever member) increases at a nearly constant rate with respect to the displacement of the contact needle in the sample direction. When the force applied by the contact needle on the sample surface exceeds a certain value, changes occur on the sample surface such as peeling off of the coating on the sample surface, and this causes the frictional force between the sample surface and the contact needle to increase. The amount of twist of the elastic lever member also changes irregularly due to the sudden change. The force applied by the contact needle onto the sample surface at this time can be accurately determined from the elastic modulus of the elastic lever member and the amount of displacement of the contact needle in a direction approximately perpendicular to the sample surface. Mechanical properties of the sample surface, such as adhesion strength, can be obtained.

According to this method, the displacement of the contact needle in a direction approximately perpendicular to the sample surface can be directly and accurately measured, and the load on the contact needle when the sample surface changes can be accurately determined, even when the sample surface is not flat, such as concave or convex. , the mechanical properties of the sample surface can be accurately obtained.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a schematic diagram showing a horizontal vibration type scratch tester according to an embodiment of the present invention. In the figure, an elastic lever 109 is fixed to a piezoelectric element 107, and a contact needle 110 extending downward is provided at the lower end of the elastic lever 109.
A reflecting mirror 108 facing upward is fixed at the top of each tip. The vibration device mount 101 is fixed to the test machine main body (not shown), and the vibration device 102 is attached to the vibration device mount 101. The vibration device 102 is caused to vibrate at low frequency in the X-axis direction by an oscillator 103. A piezoelectric element 107 to which an elastic lever 109 is fixed is fixed to a vibrating device 102. When the elastic lever 109 is displaced in the X-axis direction due to a load in the X-axis direction, the piezoelectric element 10
7 generates a potential, which is amplified by an amplifier 105 electrically connected to the piezoelectric element 107.

Almost directly above the reflecting mirror 108 is an optical displacement meter probe 1.
06 is installed. Optical displacement meter probe 106
is electrically connected to the optical displacement meter 104.

On the other hand, a sample 111 is fixedly placed on an xyz-axis fine movement device 112 below the contact needle 110 by a fixing mechanism (not shown). The XYZ axis fine movement device 112 is
It is possible to move slightly in the Y and Z axis directions, and the sample 111
The positional relationship between the contact needle 110 and the contact needle 110 can be freely set. Furthermore, it is movable in the Y-axis direction at a desired speed. Furthermore, it is rotatable in the θ direction.

Next, a method for measuring the adhesion of a thin film on a sample surface using this device will be described.

First, place the sample 111 so that the contact needle 110 faces the sample 111 with an appropriate distance at the location to be measured on the sample surface.
Adjust position 1. Furthermore, the surface of the sample or the contact needle 110
The sample is rotated in the θ direction so that the sample surface is tilted slightly from a position perpendicular to the longitudinal direction of the sample and the sample surface is upward-slanted to the right in the figure. Then, the vibration device 102 is caused to vibrate at a low frequency in the X-axis direction, and the contact needle 110 is caused to vibrate at a low frequency in the X-axis direction on the sample surface. Along with this low frequency vibration, the sample 11
1 in the minus Y direction (left side of the page) at a constant speed. As the sample 111 moves in the Y direction, the surface of the sample in contact with the contact needle 110 moves in the Z-axis direction (upward in the paper), and therefore the elastic lever 109 is also displaced in the same direction. The amount of displacement at this time is detected by the optical displacement meter 104 from a change in the distance between the reflecting mirror 108 and the optical displacement meter probe 106. Further, the load applied to the thin film on the sample surface by the contact needle 110 is determined from the amount of displacement and the spring constant of the elastic lever 109.

At this time, if the load applied to the thin film is small, the vibration device 1
02 and the elastic lever 109 vibrate together in the X-axis direction. However, as the sample 111 moves, the load applied to the thin film on the sample surface increases, so the contact needle 111
The frictional force between the sample and the thin film on the sample surface increases. Then, since the vibration of the elastic lever 109 no longer follows the vibration of the vibration excitation device 102, the elastic lever 109 and the piezoelectric element 1
A torsional displacement occurs between 0.07 and 0.07. This torsional displacement is
Detected by amplifier 105.

Here, the amount of torsional displacement increases as the load increases, but when the load reaches a certain value, the amount of torsional displacement changes rapidly. This is because the frictional force changes to the frictional force of the base when the thin film in the area in contact with the contact needle 110 is broken. Therefore, the adhesion force of the thin film can be measured by the load at the location where the torsional displacement has drastically changed.

FIG. 2 is a schematic diagram showing a horizontal vibration type scratch tester according to another embodiment of the present invention.

The difference from the above embodiment is that a grounding electrode 208 and a capacitance measuring probe 206 are provided in place of the reflecting mirror 108 and the optical displacement meter probe 106, and the distance between them is measured using these, and the capacitance is measured. This distance is detected as a change in current value by the amplifier 204b via the bridge 204a. Other operations are the same as in the above embodiment.

Next, an example in which the adhesion of a vapor deposited film on a glass surface was measured using the testing machine shown in FIG. 1 will be described.

The samples measured were of the following three types: a' to c.

Sample a: A thin film of MgF2 was formed by vacuum evaporation on a lens (material: BK-7) with one side flat and the other side convex with a radius of curvature of 10 mm. The substrate temperature during thin film formation was 300°C, and the thickness of the formed thin film was 1
000 people.

Sample B: One side or flat, the other side has a polarity radius of 10n+m
The film was formed on a concave lens under the same conditions as above.

Sample C: BK-7 with flat both sides (diameter 30 mm
) The film was formed on the plate material under the same conditions as above.

The contact needle is made of diamond and has a tip radius of 15μ.
m was used. The elastic lever used had a relationship between the displacement in the Z direction and the load, which showed a linear displacement of 1 μm for a load of 0.1 gram. The scratch speed is the moving speed of the sample in the minus Y direction at 8 μm/SeC.
And so. The horizontal vibration frequency of the elastic lever was 30 Hz.

In the measurement, first, sample a is placed on the XYZ fine movement device of the testing machine so that the flat side faces down. However, the inclination θ of the XYZ fine movement device is θ=0°. After adjusting the position of the XYZ fine movement device, sample a
is moved at a constant speed in the minus Y direction. At this time, the load detected by the optical displacement meter corresponding to the upward displacement of the contact needle is plotted on the X-axis, and the relative value of the gain obtained from the amplifier is plotted continuously on the Y-axis. In other words, find the breaking point of the thin film on the sample surface.

Similarly, for sample S and sample C, locations where the gain changes drastically are determined. However, in sample C, θ=2'
shall be.

FIG. 4 is a superimposed graph of the load-amplifier gain relative value for the sample aNC obtained in this manner. In the figure, curves 5Il-3c are for sample a''
-' The results for c are shown.

This means that if the material is the same and the film formation conditions are the same,
It can be seen that the adhesion of the film can be measured with good reproducibility even when the sample surface shape is different.

In the examples, the displacement of the elastic lever caused by the frictional force between the contact needle and the sample surface is detected by a piezoelectric element, but the present invention is not limited to this method, and the displacement Any method that can detect with high sensitivity may be used. Another method may be to provide a magnetic body on the lever, such as in a record player cartridge, and detect the displacement using a coil.

Next, as a comparative example, all conditions were the same as in the previous example except that the load applied to the contact needle was changed using the method shown below. I was looking for a place of drastic change.

That is, here, the sample surface is assumed to be approximately flat by setting θ of the XYZ fine movement device to 2°, and the sample surface itself is also assumed to be θ=2°. Then, the load applied to the contact needle is calculated by calculating the amount by which the sample has moved in the Z direction and the amount by which the sample has moved in the minus Y direction, and then by multiplying this by a spring constant.

FIG. 5 is a graph of the load-amplifier gain relative value obtained in this manner.

According to this, it can be seen that even if the film is formed using the same material and under the same conditions, it is not possible to measure the adhesion of the film with good reproducibility if the sample surface shape is different.

[Effect of the invention] As explained above, in the vibrating scratch tester,
Since the displacement of the contact needle in the sample direction is detected and the load applied to the contact needle is determined based on the detected displacement, the adhesion force of the thin film on the sample surface under the contact needle can be measured with high accuracy.

Further, thin films on surfaces of shapes other than flat surfaces, such as convex lenses, can also be measured with high precision.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of a horizontal vibration type scratch tester according to an embodiment of the present invention using an optical displacement meter, and FIG. 2 is another embodiment of the present invention. FIG. 3 is a front view showing the configuration of a horizontal vibration scratch tester using a capacitance bridge, which is a horizontal vibration scratch tester according to the prior art. , Figure 4 is a graph of the breaking point of the thin film on the sample surface determined using the tester shown in Figure 1, and Figure 5 is a graph showing the breaking point of the thin film on the sample surface determined using the conventional load measurement method as a comparative example. This is the graph I found. DESCRIPTION OF SYMBOLS 101. Vibration device mounting base, 102 Vibration device, 103 Oscillator, 104. Optical displacement meter, 105: Amplifier, 106: Probe for optical displacement meter, 107. Piezoelectric element, 108 Reflector, 110: 111: 112 : 204 a 204 b 206 : 208 ・312 : Elastic lever contact needle, sample, XYZ axis fine movement device, capacitance bridge, amplifier, capacitance measurement probe, ground side electrode, oscilloscope, sample stand.

Claims (3)

[Claims] (1) A contact needle that contacts the sample; holding the contact needle; and applying a force to the contact needle that causes the displacement of the contact needle in a direction perpendicular to the sample surface to vary over time; an elastic lever member brought into contact; a moving means for moving the sample in a predetermined direction along the sample surface relative to the elastic lever member; and a moving means for holding the elastic lever member in a direction of movement by the moving means. an excitation means for vibrating in a direction along a vertical sample surface; a torsion state detection means for detecting a twist state of the elastic lever member; and a contact needle held by the elastic lever member substantially perpendicular to the sample surface. 1. A vibratory scratch tester comprising: displacement amount detection means for detecting a displacement amount in a direction. (2) The displacement detection means includes a reflecting mirror whose position is fixed with respect to the contact needle, and an optical displacement meter probe for detecting the displacement of the contact needle by receiving the reflected light from the reflecting mirror. The vibrating scratch tester according to claim 1, further comprising: (3) The displacement amount detection means includes an installed electrode whose position is fixed with respect to the contact needle, and a capacitance measuring probe that is paired with the installed electrode to accumulate electric charge and detect the capacitance. A vibrating scratch tester according to claim 1.