JP2003246971A - Method for adhering foil or film, and target for measuring shock wave speed, obtained by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for adhering a foil or a film having a thickness suitable for a material in a field in which a machining accuracy of a submicron order is required such as target for measuring laser-induced shock wave speed, to provide a P-N type semiconductor and an electrode for solar battery without using an adhesive. <P>SOLUTION: The method for adhering the foil or the film comprises for forming an organic monomolecular film on the surface of the object, B, and adhering the film or the foil, A through the monomolecular film. The first step comprises wetting the B with a first organic solvent dissolving a surface- treating agent enabling self assembly, and washing the surface with a second organic solvent same to or different from the first organic solvent. The second step involves putting the surface and the A together while leaving the second organic solvent on the surface of the B so that air may not present between them. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adhering a metal foil, and this adhering method has a submicron-order processing accuracy particularly for P-N junction type semiconductors, solar cells, shock wave velocity measurement targets and the like. It can be suitably used in the required manufacturing field.

[0002]

2. Description of the Related Art In the field of manufacturing PN junction type semiconductors, solar cells, shock wave velocity measurement targets and the like, the thickness of the joint between members may affect the performance.
For example, after separately forming a P-type semiconductor and an N-type semiconductor,
When a PN junction type semiconductor is completed by joining, if a thick adhesive layer is interposed between the two, it becomes difficult for electrons to move between PN, so it is desirable to join without an adhesive.
The same applies to the junction between the silicon and the electrode in the solar cell. Therefore, conventionally, only the direct bonding method such as the vapor deposition method has been usually available. In the measurement of shock wave velocity, a substance to be measured adhered to a part of the surface of a shock wave driving substance is used as a target for measurement. The impedance mismatch method and the direct measurement method using a velocity interferometer are known as methods for measuring the velocity of a shock wave. In the case of the impedance mismatch method, the standard substance is also attached to the surface of the shock wave driving substance side by side with the substance to be measured. Then, by simultaneously measuring the time taken for the shock wave emitted from the shock wave driving substance to pass through the measured substance and the standard substance, and dividing each thickness of the measured substance and the standard substance by the respective shock wave passage time, Speed is required. The standard substance is a substance whose Hugoniot function is already well known, and the Yugonio function of the substance to be measured can be obtained by comparing the shock wave velocity with the velocity of the shock wave of the substance to be measured. In the case of the direct measurement method, only the substance to be measured is bonded to the surface of the shock wave driving substance.

In any case, the shock wave velocity is still obtained by dividing the thickness of the substance to be measured by the transit time of the shock wave. Then, the passage time is the time from immediately after the shock wave is emitted from the shock wave driving substance to when the shock wave is completely passed through the substance to be measured. Therefore, in a structure in which the shock wave driving substance and the substance to be measured are adhered using an adhesive, the time taken for the shock wave to pass through the adhesive is also displayed as the above passage time. It is desirable that the thickness of the adhesive is as thin as possible compared to the thickness. In this respect, the conventional shock wave generated using explosives has a long steady-state duration, so the substance to be measured can be made sufficiently thick, and there is no problem even if the thickness of the adhesive is ignored. .

[0004]

On the other hand, since the shock wave in recent years generated by laser induction has a short duration, the substance to be measured and the driving substance also have to be thin,
The thickness of the adhesive cannot be ignored. Therefore, for example, the driving substance should be sputtered on a thermally decomposable organic substance, and the substance to be measured must be formed thereon by a vapor deposition method such as sputtering without using an adhesive, and then the organic substance must be thermally decomposed and removed. did not become.

However, the first problem with the vapor deposition method is that it takes a very long time to obtain the film thickness required for measurement. The second problem is that the obtained thin film has a low adhesive strength, so that it may be destroyed during the moving process before being subjected to the measurement, which makes it difficult to handle. These problems are described in P above.
The same applies to -N type semiconductors and solar cells. The third problem is that the substance to be measured is limited to metal, and a material having no heat resistance such as an organic polymer cannot be used as the substance to be measured. Therefore, an object of the present invention is to bond a foil-shaped or film-shaped object having an appropriate thickness to a laser-induced shock wave velocity measurement target, a semiconductor, an electrode of a solar cell or the like to an object without using an adhesive. To provide a way to do.

[0006]

In order to solve the problem, the bonding method of the present invention is a method for bonding a foil-shaped or film-shaped object having a mirror surface to an object, A, when the object is B, it comprises a first step of forming an organic monomolecular film on the surface of B and a second step of adhering to the mirror surface of A via the organic monomolecular film. Characterize. Here, the mirror surface means a surface having an average surface roughness of 1 μm or less, preferably 0.5 μm or less.

According to the bonding method of the present invention, the organic monomolecular film is covalently bonded to the B, and the organic monomolecular film and the mirror surface of the A are bonded by the action of intermolecular force and negative pressure.
Therefore, the adhesive strength is high and they do not separate from each other in the normal movement process. In addition, since the adhesive surface of the foil-shaped or film-shaped object A is a mirror surface, and only the organic monomolecular film is interposed between the object A and the object B, the thickness of the adhesive layer is Is negligible with respect to the thickness of foil-shaped or film-shaped objects and objects. Therefore, even if the adhesive layer is interposed between the P-N junction and between the electrode and the power generation material, the electric resistance of the adhesive layer can be substantially ignored. If an organic monomolecular film that is the same as or different from the surface of B is formed on the surface of A, which is a mirror surface, the adhesive force increases.

Further, the object B is not limited to a metal and may be an inorganic material such as glass, as long as an organic monomolecular film can be formed by self-organization or the like. The shape of the object B is also not limited, and B may be foil-shaped or film-shaped. On the other hand, organic monomolecular film and foil-shaped or film-shaped object A
Is adhered by the action of intermolecular force and negative pressure,
A is not limited to an inorganic substance such as a metal and may be an organic polymer. However, when the following preferred first and second steps are adopted, A and B are limited to those having an organic solvent-philic surface.

As preferred first and second steps of the present invention, in the first step, B is wetted with a first organic solvent in which a self-assembling surface treating agent is dissolved, and the first organic solvent is used. And a step of washing with a second organic solvent which is the same as or different from the above.
It includes operations that are combined with. The object B
When forming a foil or film, when combining with A, A
B may be backed with a thick member so that the surface of B and the surface of B are in close contact with each other.

When the object B is wetted with the first organic solvent in which the surface treating agent is dissolved, the surface treating agent self-assembles on the object B and is arranged for each single molecule to covalently bond with the object B. When alkylhalosilane is used as the surface treatment agent, the state shown in FIG. 1 is obtained. Subsequently, a by-product of this reaction (Fig. 1
In the case of, HCl) is removed with a second organic solvent. Object B
Only the organic monolayer derived from the surface treatment agent and the second organic solvent remain on the top. The usual means for aligning the foil-shaped or film-shaped object A and the object B without the presence of air is to carry out in a second organic solvent. The combined combination of A and B is taken out of the second organic solvent and rubbed from the approximate center of A toward the periphery while applying pressure in the thickness direction, whereby the excess second organic solvent is removed. In this way, A and the organic monomolecular film are bonded by the action of intermolecular force and negative pressure.

The surface treatment agent is preferably at least one selected from alkylsilane, alkylalkoxysilane, alkylhalosilane, alkylthiol and alkylisonitrile. The second organic solvent is, for example, an aliphatic hydrocarbon having 6 or less carbon atoms or an aliphatic monoalcohol. Therefore, the shock wave velocity measuring target obtained by the method of the present invention is a shock wave velocity measuring target consisting of the measured substance and the shock wave driving substance adhered to the measured substance, and the measured substance is a foil-shaped or film-shaped object, Shock wave driving material is made of metal foil,
It is characterized in that the adhesion is performed via an organic monomolecular film formed on at least one surface.

[0012]

[Examples] -Examples-Examples of the bonding method of the present invention will be described below. In this example, both the first organic solvent and the second organic solvent were hexane.
Isobutyltrichlorosilane was used as the surface treatment agent. In this example, both A and B defined in the claims are metal foils.

[Adhesion of metal foil] 10 m of dried hexane (Kanto Chemical Co., Ltd.) on a sufficiently dried glass dish.
l and isobutyltrichlorosilane (manufactured by Tokyo Kasei) 0.5
g were mixed and dissolved. Two square aluminum foils each having a side of 2 cm, a thickness of 5 μm and an average surface roughness of 0.3 μm were immersed in this solution for 5 minutes. Subsequently, the surface of the aluminum foil was washed with hexane, and the two aluminum foils were again immersed in pure hexane.

Next, the aluminum foil was moved with tweezers so that the surface of the foil was sufficiently blended with hexane, and then the main surfaces of the two foils were put together in hexane. Then, it was taken out from hexane as it was, and placed on a flat table so that one foil faced up. Immediately, the upper surface of the foil was rubbed from the center toward the periphery to push hexane out of the foil, and a glass plate was placed on the foil and pressed down, and left for several hours.
After a while, voids composed of bubbles, which are thought to be derived from hexane that volatilized, were formed at the interface between the foils as shown in FIG. Then, the glass plate was rubbed to push out the bubbles. Adhesion was determined to be complete when no bubbles were generated.

[Evaluation] When two aluminum foils bonded to each other were dropped onto concrete from a height of 1 m in the atmosphere, the aluminum foils were not separated from each other. The same was true in vacuum. For comparison, when the aluminum foils were combined under the same conditions as above except that no surface treatment agent was used, they were separated from each other at the same time when they were dropped.

The interface between the two bonded aluminum foils is viewed from the side as shown in the upper part of FIG.
M-840) was observed at 1000 times magnification, and the photographed image is shown in FIG. 3 (bottom). As can be seen in FIG. 3 (bottom), since only the unevenness of the aluminum foil can be confirmed in the gap between the adhesive surfaces, the thickness of the adhesive layer is negligible. Further, since the microscopic observation is performed in a high voltage of 3 kV in a vacuum, it is shown that the bonded portion is not damaged even in this environment.

Example 2-Two aluminum foils each having a thickness of 10 μm,
The aluminum foils were bonded under the same conditions as in Example 1 except that the area of one aluminum foil was smaller than that of the other. For convenience, in this example, a small area aluminum foil is referred to as a step, and a large area aluminum foil is referred to as a base.

A laser focusing altimeter (manufactured by Keyence Corporation) was used to measure the thickness of the two bonded aluminum foils.
The upper part of FIG. 4 shows the cross-sectional shape of the laminated body including the steps and the base, and the lower part shows the measurement results. As can be seen in FIG. 4, the step thickness is 9.60 μm and the average surface roughness is 0.3 μm.
It was m.

Next, a laser-induced shock wave test was conducted with the adhered aluminum foil laminate as a target in the following procedure. The test was conducted at the Laser Fusion Research Center, Osaka University, using a high-intensity laser (Gekkou Module GMII). The temporal behavior of the laser pulse was Gaussian distribution. The laser light was directed directly onto the target in the approximately 500 μm diameter range by a lens of f = 1000 mm. Irradiation energy is laser intensity 9.3 × 10 ¹² W
It was set to 30 J corresponding to cm ^-2 .

When a shock wave propagates through a flat target, the shock radiated from the back surface of the target emits black body radiation depending on the shock temperature. The emissivity on the back surface of the target at this time was measured using a time streak camera.
The signal is collected by the F / 1.2 objective lens and imaged on the slit of the streak camera by the imaging lens, and the streak camera is charged by a charge coupled device (CCD) camera (16 bits,
512 × 640 pixels). The detectable wavelength of this streak camera was 300 to 1600 nm, the spatial resolution was better than 9 μm on the target, and the temporal resolution was better than 137 ps.

The emissivity was determined based on the imaging of the shock wave emitted from the back surface of the target. The emissivity is shown in FIG. 5 as a function of time corresponding to the vertical section of the image. The time from the reference point to the shock wave emission was 3.74 ns and 3.77 ns in the laminate and the single layer, respectively, as shown in FIG. Laser energy of each shot is 12.7J
And 12.5 J, the difference was almost equal to 1.5% and the time resolution was 0.1 ns. Therefore, the thickness of the adhesive layer of the laminate is negligible in shock wave velocity measurement.

[0022]

Since the metal foil can be adhered without using an adhesive, the error due to the adhesive layer can be eliminated, which is useful in various applications where dimensional accuracy on the order of submicrons is important.

[Brief description of drawings]

FIG. 1 is a diagram showing a bonding structure between an aluminum foil surface and an organic monomolecular film.

FIG. 2 is a cross-sectional view showing a process of bonding aluminum foils to each other.

FIG. 3 is a diagram showing an image pickup direction of an interface between two bonded aluminum foils by an electron microscope in the upper stage, and a photographed image is shown in the lower stage.

FIG. 4 is a cross-sectional view showing two bonded aluminum foils, and a lower graph is a graph showing the results of measuring the thickness of the laminate with a laser focusing altimeter.

FIG. 5 is a graph showing a relationship between emissivity and time corresponding to a vertical section of an image.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuo Tanaka             3-12-10 Sakura, Minoh City, Osaka Prefecture F-term (reference) 4J040 HB09 HC17 HD03 HD32 JB11                       KA23 MA02 MB03 PA04 PA07

Claims (6)

[Claims] 1. A method for adhering a foil-shaped or film-shaped object having a mirror surface to an object, wherein the foil-shaped or film-shaped object is A,
When the object is B, it comprises a first step of forming an organic monomolecular film on the surface of B, and a second step of adhering to the mirror surface of A via the organic monomolecular film. How to glue. 2. In the first step, B is wetted with a first organic solvent in which a self-assembling surface treatment agent is dissolved, and washed with a second organic solvent which is the same as or different from the first organic solvent. 2. The operation according to claim 1, wherein the second step includes an operation of combining the surface B with the surface A so that air is not present in the state where the second organic solvent remains on the surface B. Method. 3. An organic monomolecular film which is the same as or different from the surface of B is formed on the surface of the foil-shaped or film-shaped object A,
The method according to claim 1 or 2, wherein the object B has a foil shape or a film shape which is the same as or different from A. 4. The method according to claim 2, wherein the surface treatment agent is one or more selected from alkylsilane, alkylalkoxysilane, alkylhalosilane, alkylthiol and alkylisonitrile. 5. The second organic solvent is an aliphatic hydrocarbon or aliphatic monoalcohol having 6 or less carbon atoms.
5. The method according to any one of 4 to 4. 6. A shock wave velocity measuring target comprising a substance to be measured and a shock wave driving substance adhered thereto, wherein the substance to be measured is a foil-shaped or film-shaped object, the shock wave driving substance is a metal foil, and the adhesion is A shock wave velocity measurement target, characterized in that the target is formed through an organic monomolecular film formed on at least one surface.