JPH0628712U - Thin film adhesion measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to evaluate the adhesion of a thin film formed on a substrate with high accuracy and to measure the adhesion of a very thin film with a thickness of nm. A thin film scratching body (14) having a plurality of projections (16) pressed against a thin film with different contact pressures and scratching a plurality of locations of the thin film (2) by the projections (16) and a probe (21) closely facing the surface of the thin film (2) at the tip. The base end of the thin film 2 is supported at a constant level to scan a region including the scratched portion of the thin film 2, and the thin film 2 is displaced according to the surface state of the thin film 2 by an atomic force acting between the tip of the probe 21 and the thin film 2. Thin film copying element 19 and detector 23 for detecting displacement of the copying element 19
Equipped with.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for measuring the adhesive force of a thin film formed on a substrate.

[0002]

[Prior art]

 Conventionally, a metal film, a metal oxide film, a silicon oxide film, a silicon nitride film, an organic monomolecular film, etc. formed on a substrate by vapor deposition, sputtering, plasma CVD, LB (Langmuir-Blodgett), etc. The adhesion strength of the thin film is measured by a scratch tester.

The above-mentioned scratch tester is for rubbing the surface of a thin film formed on a substrate to check the degree of peeling of the thin film. The adhesion of the thin film to the substrate is determined by rubbing the thin film surface with a predetermined force. It is evaluated by observing the presence or absence of peeling with an optical microscope.

[0004]

[Problems to be solved by the device]

 However, in the measurement of the adhesion force of the thin film by the scratch tester, it is difficult to evaluate the adhesion force of the thin film with high accuracy because the presence or absence of peeling of the thin film can be determined only with an accuracy that can be observed with an optical microscope. However, the adhesion force of an extremely thin film in the unit of nm (nanometer) could not be measured.

The object of the present invention is to evaluate the adhesion force of a thin film formed on a substrate with high accuracy and to measure the adhesion force of an extremely thin film with a thickness of nm unit. An object is to provide a force measuring device.

[0006]

[Means for Solving the Problems]

 The adhesion force measuring device of the present invention has a plurality of protrusions that are pressed against a thin film by different contact pressures, and a thin film scratching body that scratches a plurality of locations of the thin film by these protrusions, and a probe that is close to the surface of the thin film at its tip. The thin film has a needle supported at a constant level at its proximal end to scan a region including a scratched portion of the thin film, and the atomic force acting between the tip of the probe and the thin film causes the thin film to change in accordance with the surface state of the thin film. It is characterized in that it comprises a thin film scanning element that is displaced and a detector that detects the displacement of the scanning element.

[0007]

[Action]

 That is, the adhesion measuring device of the present invention scratches a thin film formed on a substrate with a thin film scratching body, and scans a region including a scratched portion of the thin film with a thin film copying element to inspect whether or not the thin film is peeled. Since the copying element is displaced according to the surface condition of the thin film, the presence or absence of peeling at the scratched portion of the thin film can be known by detecting the displacement of this copying element with a detector.

In this adhesion force measuring apparatus, since the copying element is displaced by the atomic force acting between the thin film surface and the tip of the probe that closely faces the thin film surface, the thin film surface formed by the copying element is displaced. The accuracy of scanning is high, and therefore the presence or absence of peeling of the thin film can be detected with high accuracy, and the adhesion of the thin film can be evaluated with high accuracy. Can be measured.

Moreover, in this adhesion force measuring device, since the thin film scratching body scratches a plurality of portions of the thin film by a plurality of projections which are pressed against the thin film by different contact pressures, a plurality of scratching forces (for the thin film) The presence or absence of peeling of the thin film with respect to the contact pressure of the protrusion) can be detected at the same time, and thus the adhesive force of the thin film can be efficiently measured.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing the basic configuration of the adhesion measuring device, and FIG. 2 is a side view of the adhesion measuring device.

In this adhesion measuring device, a substrate supporting table 13 and a thin film scratch are provided on a device main body 10 composed of a base 11 and a beam portion 12 having one end supported by the base 11 and provided above the base 11. A body 14, a thin film copying element 19, and a detector 23 for detecting the displacement of the copying element 19 are provided.

The substrate support table 13 is for fixing and supporting the substrate 1 on which the thin film 2 is formed by means such as vacuum adsorption, and the substrate support table 13 is arranged on the base 11 of the apparatus body 10. A moving device (not shown) provided in the base 11 moves in the X and Y directions (left and right and front and back) and the Z direction (up and down).

The moving device for the substrate support table 13 includes an X-direction moving mechanism, a Y-direction moving mechanism, and a Z-direction moving mechanism, and these moving mechanisms are respectively highly precise ball screws and the like. It is composed of. The Z-direction moving mechanism also includes a fine movement mechanism that moves the substrate support table 13 up and down very slightly, and the fine movement mechanism is composed of a piezo element or the like.

The thin film scratching body 14 is composed of a plurality of elastic arms 15 (five in the figure), and each arm 15 is provided with a projection 16 to be pressed against the thin film 2 at the tip thereof. . These elastic arms 15 have different spring forces, and the projection 16 at the tip of each arm 15 is pressed against the thin film 2 on the substrate 1 with different contact pressures by the spring force of the arms 15.

In this embodiment, each arm 15 is formed by pressing one ultra-thin metal plate into a comb shape, and the length of each arm 15 is made different so that each arm 15 is different. It has a spring force.

The protrusions 16 are, for example, silicon nitride (SiN) processed into a cone shape by anisotropic etching. The protrusions 16 have a quadrangular pyramid shape as shown in FIG. And is fixed to the tip of the elastic arm 15 by adhesion.

That is, the thin film scratching body 14 presses the tips of the projections 16 on the surface of the thin film 2 with different contact pressures, and scratches the thin film 2 at a plurality of locations by the projections 16. The scratching body 14 is supported by the supporting member 18 by adhering the base portion thereof to the lower surface of the scratching body supporting member 18 which is lifted and lowered by the lifting mechanism 17 provided on the beam portion 12 of the apparatus body 10.

The elevating mechanism 17 elevates and lowers the thin film scratching body 14 above and below the thin film copying element 19, and the elevating mechanism 17 is constituted by, for example, a solenoid.

On the other hand, the thin film copying element 19 is similar to a cantilever (cantilever lever) of an atomic force microscope (AFM), and the copying element 19 is 10 ⁻⁷ to 10 ^−11. The lever piece 20 is made of a metal foil (for example, gold foil) that is bent and deformed by a force of N (Newton), and a tip end of which is provided with a probe 21 that closely faces the surface of the thin film.

The probe 21 is a cone-shaped needle formed by pulling up silicon (Si), tin oxide (ZnO) whiskers, anisotropic etching of silicon nitrite (Si N), and the like. For example, it has a conical shape as shown in FIG. 3 (b), and is adhesively fixed to the tip of the lever piece 20. The probe 21 is formed to be sharper than each projection 16 of the thin film scratching body 14 described above.

The base end of the copying element 19 (the base of the lever piece 20) is adhered to the lower surface of the copying element fixing member 22 provided on the beam portion 12 of the apparatus body 10 so that the base end is always constant. Being favored to be at the level. The copying element 19 is bent and deformed downward due to the weight of the probe 21 at the tip thereof.

That is, the copying element 19 has its base end supported at a constant level, and the scratching point () of the thin film 2 with the tip of the probe 21 at the tip closely facing the surface of the thin film 2. The scanning element 19 scans a region including a portion scratched by the thin film scratching body 14. This copying element 19 has a surface of the thin film 2 by an atomic force acting between the tip of the probe 21 and the thin film 2. The displacement (the tilt angle of the lever piece 20 changes) depending on the state.

Further, the detector 23 for detecting the displacement of the copying element 19 irradiates the upper surface of the copying element 19 (the upper surface of the lever piece 20) with a laser beam and determines the copying element from the magnification of the luminous flux of the reflected light. The amount of displacement of 19 is detected, and this detector 23 is provided on the beam portion 12 of the apparatus body 10. The adhesion force of the thin film is measured by the apparatus having the above-mentioned structure as follows.

First, the substrate 1 on which the thin film 2 is deposited is fixed on the substrate support table 13 with the thin film deposition surface facing upward, and the thin film scratching body 14 is searched for by the tip of each protrusion 16 of the copying element 19. The substrate support table 13 is raised by the Z-direction moving mechanism in a state of being lowered below the tip of the needle 21, and the tip of each protrusion 16 of the thin film scratching body 14 is brought into contact with the thin film 2 on the substrate 1. .

Next, the substrate support table 13 is moved at a constant speed in a direction from the base of the thin film scratching body 14 toward the tip thereof by the Y-direction moving mechanism, and the substrate 1 is moved together with the substrate support table 13. The plurality of locations on the thin film 2 are scratched in one direction by the protrusions 16 of the thin film scratching body 14. At this time, since the thin film 2 is in contact with only the respective projections 16 of the thin film scratching body 14 that is lowered below the copying element 19, the probe 21 of the copying element 19 is sufficiently separated from the thin film 2. It only moves above the thin film 2 in the state of being operated.

When the projections 16 of the thin film scratching body 14 are scratched at a plurality of locations on the thin film 2 in this manner, groove-like scratch marks are formed on the thin film 2 along the movement loci of the projections 16. FIG. 4 shows this state, and a to e show scratch marks by the protrusions 16.

In this case, since the protrusions 16 are pressed against the thin film 2 with different contact pressures and scratch the thin film 2, the depth of the scratches a to e formed on the thin film 2 depends on the strong scratching force (projection to the thin film 2). 16), the deeper the scratch marks scratched by the contact pressure 16), and the thin film 2 at that portion is peeled off from the substrate 1 at a position scratched by a force stronger than the adhesion of the thin film 2 to the substrate 1. A scratch mark with a depth reaching one side is made.

It should be noted that the above-mentioned scratch marks are not necessarily formed on all scratched portions, and for example, scratched marks may not be formed on the portion scratched by the protrusion 16 having the smallest contact pressure.

After the thin film 2 is scratched at a plurality of positions in this manner, the lifting mechanism 17 moves the thin film scratching body 14 so that the tips of the protrusions 16 of the thin film scratching body 14 are located above the tips of the probes 21 of the copying elements 19. The protrusions 16 are lifted to separate the projections 16 from the thin film 2, and the substrate supporting table 13 is moved by the X-direction moving mechanism and the Y-direction moving mechanism to move the probe 21 of the copying element 19 to all scratching points of the thin film 2. It is positioned so as to face one corner portion of a region including (a rectangular region surrounded by a broken line in FIG. 5).

Next, the substrate support table 13 is further raised by the fine movement mechanism of the Z-direction moving mechanism to bring the thin film 2 on the substrate 1 closer to the copying element 19, and the tip of the probe 21 of the copying element 19 is moved to the thin film. The surface of 2 is made to face closely.

In this case, when the distance between the tip of the probe 21 and the surface of the thin film 2 is about 0.8 nm or less, the atoms at the tip of the probe and the atoms on the surface of the thin film 2 are caused by mutual interference of the electron clouds. If attractive force (also called London attractive force, electrostatic attractive force, dispersive force, van der Words force, etc.) occurs and the distance between them becomes smaller to about 0.3 nm, repulsive force (repulsive force) because each electron is confined in a narrow region ( Also called exchange repulsive force, Pauli force, repulsive force, etc.).

Therefore, finally, the probe 21 of the copying element 19 closely opposes the surface of the thin film 2 at an interval where the attractive force and the repulsive force between the atom at the probe tip and the atom on the thin film surface balance. Further, when the raising of the substrate support table 13 is stopped in this state, the initial posture of the copying element 19 (the inclination angle of the lever piece 20) is determined.

Next, the displacement detection of the copying element 19 by the detector 23 is started, and thereafter, the substrate support table 13 is moved substantially in the length direction of the scratches a to e of the thin film 2 by the Y-direction moving mechanism. The table 13 is reciprocally moved in a direction orthogonal to each other, and the table 13 is moved at a slight speed in one direction by an X-direction moving mechanism, so that the entire area of the thin film 2 including the scratched portions is scanned by the copying element 19. .

FIG. 5 shows the scanning state of the thin film surface by the copying element 19, and the copying element 19 scans the surface of the thin film 2 along the locus shown by the alternate long and short dash line in the figure. In FIG. 5, the scanning locus of the scanning element 19 is shown with a large pitch for simplification of the drawing, but the pitch of the actual scanning locus is about the same as the diameter of the tip of the probe 21.

When the scanning device 19 scans the entire region including all scratched portions of the thin film 2 as described above, an atomic force between the thin film 2 and the thin film 2 always causes a constant gap ( The probe 21 that closely opposes at an interval (at which the attractive force and the repulsive force generated between the atoms are balanced) moves up and down according to the surface state of the thin film 2, and accordingly, the base end is supported at a constant level. 19 is displaced (the tilt angle of the lever piece 20 changes).

The scanning element 19 is slightly displaced according to the surface roughness of the thin film itself when scanning a portion other than the scratched portion of the thin film 2, but the scanning element 19 scans each scratched portion. When it is present, it is displaced according to the depth of the scratch mark at that location.

Since the displacement of the scanning element 19 is continuously detected by the detector 23, the amount of displacement of the scanning element 19 detected by the detector 23 is used to remove the thin film 2 at each scratching point. You can know whether or not.

It should be noted that which scratched portion of the thin film 2 the detection value of the detector 23 is the displacement amount when the scanning element 19 scans is determined by, for example, the scanning time of the scanning element 19 in the X direction and the scanning in the X direction. It can be obtained from the ratio with the time when the detected value changes significantly, and the presence or absence of peeling of the thin film 2 can be determined by the amount of displacement of the copying element 19 and the film thickness of the thin film 2 (preliminarily obtained). It can be determined by comparison with.

Further, at this time, since the thin film scratching body 14 is located above the copying element 19, each protrusion 16 of the thin film scratching body 14 is sufficiently separated from the thin film 2 and moves above the thin film 2. Therefore, the thin film 2 is not scratched by the thin film scratching body 14 during scanning of the thin film surface by the copying element 19.

Since the peeling of the thin film 2 occurs at a portion scratched by a force stronger than the adhesion of the thin film 2 to the substrate 1, if the presence or absence of peeling at each scratched portion of the thin film 2 is known, From the contact pressure of each projection 16 of the thin film scratching body 14 on the thin film 2 (spring force of the elastic arm 15), the adhesive force of the thin film 2 on the substrate 1 can be obtained.

That is, for example, in FIG. 5, the displacement amount when the scanning element 19 scans on the scratch traces a to c is a value smaller than the film thickness of the thin film 2 and is traced on the scratch trace d. Assuming that the displacement amount when the element 19 scans is the same as the film thickness of the thin film 2, the adhesion force of the thin film 2 is larger than the thin film contact pressure of the protrusion 16 that causes the scratch mark of c, and the scratch force of d. It is a value smaller than the thin film contact pressure of the protrusion 16 that caused the mark.

That is, in the above-described adhesion measuring device, the thin film 2 formed on the substrate 1 is scratched by the thin film scratching body 14, and the region including the scratched portion of the thin film 2 is scanned by the copying element 19 to peel off the thin film 1. Since the copying element 19 is displaced according to the surface condition of the thin film 2, if the detector 23 detects the displacement of the copying element 19, the thin film 2 is peeled off at the scratched portion. You can know whether or not.

In this adhesion force measuring apparatus, since the copying element 19 is displaced by the atomic force acting between the tip of the probe 21 and the thin film 2 that are closely opposed to the surface of the thin film 2, the copying element 19 is displaced. The accuracy of scanning the surface of the thin film by 19 is high. Therefore, the presence or absence of peeling of the thin film 2 can be accurately detected, and the adhesion of the thin film 2 can be evaluated with high accuracy. It is also possible to measure the adhesion of very thin films in units.

Moreover, in this adhesion measuring device, since the thin film scratching body 14 is scratched at a plurality of locations on the thin film 2 by the plurality of projections 16 pressed against the thin film 2 with different contact pressures, a plurality of scratches is obtained. The presence or absence of peeling of the thin film 2 with respect to the force (contact pressure of the protrusion 16 against the thin film 2) can be detected at the same time, and therefore, the adhesive force of the thin film 2 can be efficiently measured.

In the above-mentioned embodiment, each elastic arm 15 of the thin film scratching body 14 is formed by pressing one ultra-thin metal plate into a comb shape, but these elastic arms 15 are springs. The elastic arms 15 may be individually formed of metal plates having different constants, and in that case, the elastic arms 15 may have the same length.

Further, in the above embodiment, the thin film 2 is scratched linearly, but scratching of the thin film 2 may be arbitrary, for example, meandering scratching, or the scanning direction by the copying element 19 may be arbitrary.

Further, in the above-mentioned embodiment, the measurement of the adhesion force of the thin film 2 formed directly on the substrate 1 to the substrate 1 was described. However, the adhesion measuring device of the present invention is the lower layer of the conductive film or the insulating film. It can also be used for measuring the adhesion of a thin film formed on a film-formed substrate to the lower layer film.

[0048]

[Effect of device]

 The adhesion force measuring device of the present invention has a plurality of protrusions that are pressed against a thin film by different contact pressures, and a thin film scratching body that scratches a plurality of locations of the thin film by these protrusions, and a probe that is close to the surface of the thin film at its tip. The thin film has a needle supported at a constant level at its proximal end to scan a region including a scratched portion of the thin film, and the atomic force acting between the tip of the probe and the thin film causes the thin film to change in accordance with the surface state of the thin film. Since it is equipped with a displacing thin film scanning element and a detector that detects the displacement of the scanning element, the adhesion of the thin film formed on the substrate can be evaluated with high accuracy, and the film thickness is in nm units. It is possible to measure the adhesion force of an extremely thin film, and it is also possible to detect whether or not the thin film is peeled off due to multiple scratching forces at the same time, so that the adhesion force of a thin film can be measured efficiently. Kill.

[Brief description of drawings]

FIG. 1 is a perspective view showing a basic configuration of an adhesion measuring device.

FIG. 2 is a side view of the adhesion measuring device.

FIG. 3 is an enlarged perspective view showing the shapes of the protrusion of the thin film scratching body and the probe of the thin film copying element.

FIG. 4 is a plan view showing a state where the thin film is scratched by a thin film scratching body.

FIG. 5 is a plan view showing a scanning state of the thin film surface by the thin film copying element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Thin film 10 ... Device body 13 ... Substrate support table 14 ... Thin film scratching body 15 ... Elastic arm 16 ... Projection 19 ... Thin film copying element 20 ... Lever piece 21 ... Probe 23 ... Detector ae ... Scratch marks

Claims (1)

[Scope of utility model registration request] 1. An apparatus for measuring the adhesive force of a thin film formed on a substrate, comprising a plurality of protrusions that are pressed against the thin film with different contact pressures, and these protrusions are used to form a plurality of portions of the thin film. A thin film scratching body for scratching, and a tip having a probe that closely faces the surface of the thin film at the tip and supported at a constant level at the base end to scan a region including the scratched portion of the thin film, and the tip of the probe and the Adhesion force measurement of a thin film, comprising: a thin film copying element that is displaced according to a surface state of the thin film by an atomic force acting between the thin film and a detector that detects displacement of the copying element. apparatus.