JPH01185431A - Apparatus for measuring bonding strength - Google Patents

Abstract

PURPOSE:To accurately measure bonding strength, by providing a pressure element, an AE sensor and a load cell. CONSTITUTION:When a specimen 1 is set to a support shaft and a motor 9 is driven, a substrate is bent by a pressure element 6. At this time, the signals of all of a displacement converter 10, an AE sensor 2 and a load cell 5 are taken in a personal computer at every certain interval. Then, bending quantity is increased until a film is released and, after the release of the film is sufficiently generated, the rotation of the motor 9 is stopped. From the taken-in data, the correlation of bending quantity, load, the amplitude strength of acoustic emission and a count number is calculated. By this method, no excessive force is applied to the film and bonding strength can be accurately measured even with respect to a flexible substrate or a specimen low in bonding strength.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for measuring the adhesion strength of a film formed on a substrate.

(Prior art) A method of measuring the adhesion force of a film created on a substrate involves bonding tape, rods, rivets, etc. to the surface of the film, and applying forces such as pulling, twisting, and pulling down to the film. Known methods include an adhesion method in which adhesion is determined based on the presence or absence of peeling, and a scratching method in which the surface of the membrane is scratched with an indenter and adhesion is determined from the pressure of the indenter at which peeling begins.

(Problem to be solved by the invention) However, in the adhesive method, tapes, rods, rivets, etc. are directly attached to the surface of the membrane, so stress, strain, etc. are applied to the membrane by the adhesive tape, adhesive, etc. ,
For example, in the case of a sample with weak adhesive strength, peeling may already occur due to this stress or strain, making it difficult to accurately measure the adhesive strength. In the scratching method, when a soft material such as plastic is used for the substrate, the substrate itself is easily deformed by the indenter and uneven force is applied to the membrane, which tends to cause errors in the measured values.

In addition, since development called peeling is accompanied by destruction of the substance, the adhesion force itself varies greatly, and statistical processing of the data is required to perform quantitative measurements with high precision. It is necessary to conduct tests on a large number of samples.

(Means for Solving the Problems) The adhesion force measuring device of the present invention includes a mechanism that gives deflection to a substrate, a part that measures this deflection, and detects acoustic emissions generated from the substrate, the film, or the interface between the two. It is characterized by waiting for a mechanism to do so.

(Function) In the adhesion force measuring device of the present invention, the interface is made by deflecting the substrate without bringing anything into contact with the part where the film peels off, except for the indenter and support shaft for applying deflection. Since the film is peeled off by applying force, no unnecessary force is applied to the film, and the adhesion force can be accurately measured even when using a soft substrate or a sample with weak adhesion force. Furthermore, since the peeling phenomenon is detected by acoustic emissions generated from the substance, it is also possible to observe the process of minute peeling that is invisible to the naked eye or a naked eye. Furthermore, since a large number of acoustic emissions are observed in a single test, by statistically processing them, we can determine the dispersion of adhesion force, the average value, etc., which would not be possible with conventional methods when testing a large number of samples. Unobtainable knowledge is obtained by testing - samples.

(Example) Hereinafter, the adhesion force measuring device of the present invention will be described according to the examples shown in FIGS. 1 to 3.

In FIG. 1, 1 is a sample whose adhesion force is to be measured. In this case, the substrate is bent so that the membrane is on the inside, but it may be bent with the membrane on the outside.

2 is an AE that detects acoustic emissions
It's a sensor. In the case of Figure 1, the AE sensor is attached to the surface of the membrane, but for example, when resin is coated on a metal or silicone substrate, the substrate is harder than the membrane and is sensitive to acoustic waves. If the propagation characteristics are good, it may be mounted on a substrate. In addition, when installing multiple AE sensors, by taking coincidence,
It is also possible to detect peeling only in a certain limited area.

3 is a support shaft for bending the base body. The shape of the portion that contacts the base body may be a sharp knife edge or an arcuate shape. In order to reduce the friction between the base and the support shaft, the support shaft may be provided with a rotatable edge as shown in FIG. 2 or a rotatable roller as shown in FIG. 3. The spindle is mounted on a table 4 that is movable up and down. Further, a load cell 5 is provided under the table 4, and the load applied to the base body can be measured. The Young's modulus of the substrate can be calculated from the deflection and load applied to the substrate.

6 is an indenter for bending the base. The shape of the tip of the indenter may be a knife edge or a circular arc, but if the substrate to be used is hard, a knife or edge is suitable, and if it is soft, a circular arc is suitable. In the case of Fig. 1, there is only one edge, that is, the base body is bent like a three-point support.
It is also possible to replace the indenter with a two-edge indenter and allow it to be bent with four-point support. The indenter 6 is moved by the guide 7.
It is movable only in the up and down direction.

A micrometer 8 converts the rotational motion of the motor 9 into linear motion and moves the indenter up and down. By selecting the rotational speed of the motor to an arbitrary value, it is possible to change the moving speed of the indenter, that is, the rate of strain applied to the base.

Reference numeral 10 denotes a displacement converter, which converts the displacement of the micrometer, that is, the amount of deflection of the base body, into an electrical signal.

In addition, the signals from the AE sensor, load cell, and displacement transducer can be input into a personal computer and data processed in a form that allows the correlation between the amount of deflection, load, peeling, etc. to be clearly understood.

Next, how to use the device will be explained.

A sample 1 is set on a support shaft 2 as shown in FIG.

When the motor 9 is driven, the base body is pushed by the indenter 6 and bends. At this time, signals from the displacement transducer, AE sensor, and load cell are imported into a personal computer at certain time intervals. The amount of deflection is increased until the film peels off, and after sufficient peeling occurs, the rotation of the motor is stopped. From the captured data, correlations among the amount of deflection, load, acoustic emission amplitude intensity, count number, etc. can be determined.

It is said to be difficult to measure using conventional methods. An example in which measurements were taken on a sample in which a film with weak adhesion was formed on a soft substrate will be described below.

Examples of measuring the adhesion force of a sample in which a metal film is deposited on a plastic substrate are shown in FIGS. 4 and 5. The vertical axis of the graph in Figure 4 is the count of acoustic emissions,
The horizontal axis is the amount of deflection. Deflection amount is 0.1-0.3mm
The peak corresponds to microscopic peeling. Deflection is 0.
When the distance exceeds 5 mm, the number of acoustic emission counts rapidly increases, and the distribution becomes such that it reaches a maximum at 0.7 mm. These peaks correspond to uniform exfoliation of the film. The force applied to the membrane due to deflection of the substrate can be determined from material mechanics calculations. In Figure 5, the horizontal axis of the graph in Figure 4 has been rewritten as the force applied to the film, and the force when the count reaches its maximum is the average adhesion force of the film, and the width of the distribution is the adhesion force itself. is the variance of

(Effects of the Invention) By using the adhesion measuring device of the present invention, it was possible to measure the adhesion of a film on a soft substrate such as plastic. Information on microscopic peeling that cannot be captured visually, as well as information on the average value and dispersion of adhesion force, which is difficult to obtain using conventional methods, was easily obtained through a single test.

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory diagrams showing an example of the apparatus used in the present invention, and FIGS. 4 to 5 are diagrams showing an example of measurement results obtained by using the adhesion force measuring device of the present invention. . In the figure, 1...sample, 2...AE sensor, 3
...Support shaft, 4...Table, 5...Load cell, 6...Indenter, 7...Guide, 8...Micro・
Meter, 9...Motor, 10...Displacement converter, 1
1... Indicates each pin. Figure 1 Figure 2 Figure 3 Aε count number

Claims (1)

[Claims] An adhesion force measuring device comprising a mechanism for applying deflection to a substrate, a mechanism for measuring the deflection, and a mechanism for detecting acoustic emissions generated from the substrate, a film formed on the substrate, or an interface between the two.