JP2000212741A - Method and device for smoothing vapor deposited film surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smooth a film surface by applying the oscillation to an object in a process to generate a vapor deposition film on the surface of the object to reduce the size of clusters and to improve the fine surface roughness of the film surface. SOLUTION: An object 2 in which a vapor deposition film is formed on an anode 5 is provided in a container of a sputtering device. An object oscillating part 9 is provided in the container, the object oscillating part 9 comprises a lamination type piezoelectric element 9a which is provided on the anode 5, one end of which is fixed to the container side and the other end of which is joined with and fixed to the object 2 with an adhesive, an oscillator 9b which supplies the AC voltage to the piezoelectric element 9a in the container, and an oscillograph 9c arranged outside the container to check the output frequency and the output wave number of this oscillator 9b. The object 2 placed on the anode 5 side is swinged in the horizontal direction by driving the piezoelectric element 9a by the AC voltage to be expanded/contracted in the longitudinal direction in the process to generate a vapor deposition film on a surface of the object 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for smoothing the surface of a deposited film when forming the deposited film on the surface of an object by ion sputtering or the like.

[0002]

2. Description of the Related Art Generally, in a vapor deposition process, a material of a vapor deposition film is opposed to an object on which the vapor deposition film is to be formed in a vacuum, and the material of the vapor deposition film is irradiated with an electron beam or an ion beam. Then, the atomic or molecular particles of the material are scattered, and the particles are attached to the surface of the object to form a vapor deposition film.

By the way, the formation of a vapor-deposited film is not a phenomenon in which the film surface of a thin film unit uniformly adheres to the surface of an object. In the case of evaporation, molecular particles are irregularly formed on the surface of the object. These will eventually cover the entire surface, and the film surface (surface) of the deposited film will be formed on the surface of the object.

That is, the process of forming a film surface by vapor deposition generally proceeds in one of the three forms shown in FIGS. 6A to 6C. In the process, the thin film surface uniformly forms a layer. Instead of being generated in an overlapping manner, atomic or molecular particles adhere irregularly to the surface of the object,
These particles cover the surface of the object and create a film surface.

In the first type shown in FIG. 6A, first, clusters (small clumps of vapor deposition film material particles) 1 adhere to the surface of an object 2 and are connected to form a film surface. -It is called a Weber (Volmer-Weber) type. This type is considered to be the most common when the interatomic force between the atoms on the deposited film side is stronger than the interatomic force between the constituent atoms of the target object and the atoms of the film.

In the second type shown in FIG. 6 (b), a monoatomic layer 3 is formed on the surface of the object 2, and when this is completed, another monoatomic layer is formed thereon, and as a result, a film grows. And Frank-v
and der Merwe) type. It is understood that this type occurs when the interatomic force between the atoms of the object and the deposited atoms is comparable to the interatomic force between the deposited atoms.

In the third type shown in FIG. 6C, a film of the monoatomic layer 3 is formed first, and then the cluster 1 is formed on the film.
Are attached to each other and connected to form a film, and are formed by Stransky-Krastanov.
-Krastanov) type. It is considered that this type occurs when the interatomic force between the target atom and the deposited atom is extremely strong.

Therefore, the film surface is not uniform in observation of the length unit at the molecular level, but is formed with fine irregularities. Observation of this state is possible by using an atomic force microscope (AFM) or the like that allows observation of length units at the molecular level. However, the process of vapor deposition changes depending on factors such as the shape of the surface of the object, temperature, and the like, and it has been difficult to say that how these molds proceed has been clarified conventionally.

On the other hand, the film surface generated by vapor deposition or the like
Not only in the semiconductor industry, but also in optical technology, tool technology and the like, it is widely used in industry. In this regard, for example, when measuring the tip diameter of a tool edge as an example, when observing the shape with a scanning electron microscope (SEM), a diamond tool or the like has a high insulating property and a gold vapor deposition film is formed on the tool surface. Required. Therefore,
It is necessary that the deposited film has a necessary minimum thickness and is flat in order to achieve the object.

[0010] Therefore, conventionally, in the practice of such vapor deposition, use in measurement samples, etc., the physicochemical, thermal, and electrical conditions are mainly adjusted, and the vapor deposition process is performed in an environment where the object is fixed and stationary. However, in such a conventional method, it is not possible to improve the function of film formation by smoothing the film surface, or to optimize the formation of the deposited film by controlling the generation speed of the film surface. It was extremely difficult.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for smoothing the surface of a deposited film which advantageously solve the above-mentioned problems. The method of smoothing the film surface is characterized in that, when a vapor deposition film is formed on the surface of a target, vibration is applied to the target during the generation of the vapor deposition film.

According to an experiment conducted by the inventor of the present invention, when a vibration is applied to an object in the process of forming a vapor-deposited film as described above, a cluster (a small particle of vapor-deposited film material particles) is clearly produced as compared with a case where no vibration is applied. Lump) became smaller, and the fine surface roughness of the film surface became finer, and a vapor-deposited film having a smooth film surface was obtained. Then, when vibration is applied to the object in the process of forming the vapor-deposited film as described above, the generation speed of the film surface is obviously slower than when no vibration is applied, and therefore, the generation speed of the film surface is controlled. It has been found that the formation of the deposited film can be optimized.

Further, the apparatus for smoothing the surface of a vapor-deposited film according to the present invention comprises: a vapor-deposited film forming unit for forming a vapor-deposited film of material particles on the surface of the object; And an object vibrating unit for applying vibration to the object during the formation of the deposited film.

According to such an apparatus, vibrations can be applied to the object in the process of forming the vapor-deposited film, so that clusters (small clumps of vapor-deposited film material particles) can be reduced as compared with the case where no vibration is applied. As a result, the fine surface roughness of the film surface can be made finer, so that a vapor-deposited film having a smooth film surface can be obtained, and the generation speed of the film surface can be reduced.

In the apparatus of the present invention, the object vibrating section supplies a piezoelectric element coupled to the object so as to vibrate the object, and supplies an electric signal to the piezoelectric element. And an oscillator for vibrating the piezoelectric element.By using such a piezoelectric element and an oscillator, the vibrating unit can be easily compacted so that it can be housed in a vacuum vessel, and the vacuum It can be configured to operate in and not electrically affect the deposition process.

Further, the vapor deposition film forming section in the apparatus of the present invention may have an ion sputtering device, and if such an ion sputtering device is used, the vapor deposition film for the target can be easily formed at a relatively low temperature. The formation can take place.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Here, FIG. 1A shows a vapor deposition film forming section in one embodiment of a vapor deposition film surface smoothing apparatus of the present invention for carrying out one embodiment of the vapor deposition film surface smoothing method of the present invention. FIG. 1B is an explanatory view schematically showing a vapor deposition process by an ion sputtering apparatus as an example, FIG. 1B is a configuration diagram showing a schematic configuration of the ion sputtering apparatus in the apparatus of the above embodiment, and FIG. FIG. 2 is a configuration diagram illustrating a schematic configuration of an object exciting unit in the device.

Ion sputtering has a feature that it can be easily deposited at a relatively low temperature, and is widely used. In the apparatus of the above embodiment, as shown in FIG. 1 (b), the inside of the container 4 of the ion sputtering apparatus is made substantially vacuum by a vacuum pump (not shown), and an anode 5 having an object 2 on which a deposition film is formed, When a DC voltage is applied between the electrode 6 and the cathode 6 having the target 6a, a glow discharge is generated between the electrodes 5 and 6, and the gas between them is ionized into cations and electrons to generate plasma. 8 will be obtained. Note that argon gas may be used as the gas, but in the apparatus of this embodiment, residual gas of air is used.

Thus, as shown in FIG. 1A, the cations in the plasma 8 are attracted to the cathode 6 side and collide with the target 6a made of the material of the deposition film on the cathode 6 side. The atoms of the material are repelled.
This is a phenomenon called spatter, in which the ejected atoms of the material continue to fly, and one of them is an anode 5
It collides with and adheres to the surface of the object 5a on the side.
Note that, in the apparatus of this embodiment, gold (A
u), and a strip of a silicon (Si) substrate generally used as a semiconductor substrate is used as the object 5a.

Although not shown in FIG. 1 in the apparatus of the above embodiment, an object vibrating section 9 shown in FIG. 2 is provided in the container 4. And a laminated piezoelectric element 9a having one end fixed to the container 4 and the other end bonded and fixed to the object 5a with an adhesive, and also arranged in the container 4 and provided with the piezoelectric piezoelectric element 9a. An oscillator 9b (specifically, a small function generating circuit board operated by a storage battery) for supplying an AC voltage to the element 9a, and the oscillator 9b is disposed outside the container 4 to check the output frequency and output waveform of the oscillator 9b. And an oscillograph 9c. Note that the oscillator 9b here has a frequency of 100 Hz to
Maximum power (pp) at any frequency between 300 kHz
Value) 2V AC voltage can be output to the piezoelectric element 9a, and the piezoelectric element 9 driven by the AC voltage can be output.
a expands and contracts in the longitudinal direction, and can vibrate the object 5a placed on the anode 5 side in the horizontal direction in FIG.

The method of the above embodiment uses the apparatus of the above embodiment to apply vibration during generation of the film surface of the vapor deposition material on the object 5a. In order to observe the generation process, a large number of substrate strips (10 mm square) as the object 5a were prepared, and for each substrate strip,
Vapor deposition was performed for 5 seconds, 10 seconds, 20 seconds, and 60 seconds, respectively, and the surface state of the substrate strip was observed with an atomic force microscope (AFM). At that time, in order to clarify the influence of the vibration, the case where no vibration was applied to the substrate strip and the case where the vibration was applied were compared for the same deposition time.
In addition, it was confirmed that it was possible to separate the substrate strip from the state in which it was joined to the piezoelectric element 9a by using an adhesive melt.

FIG. 3 (a) shows the A of the surface of the substrate strip in the case of vapor deposition for 20 seconds without applying vibration by the apparatus of the above embodiment.
FIG. 3 (b) is an observation image by AFM of the surface of the substrate strip when vapor deposition is performed for 20 seconds while vibrating at 100 kHz by the method of the above embodiment using the apparatus of the above embodiment. Are 100,000 times. The vertical axis represents the diameter of the unit shape (cluster) characteristically observed in these images (the major axis in the case of an elliptical shape), the ten-point average roughness Rz of the fine surface, and the horizontal axis represents the deposition time. The graphs of FIGS. 4 and 5 show the state of the film surface formed by the above-described vapor deposition, taking the excitation frequency as a parameter.

As shown in these graphs, vibration was applied to the substrate strip during the process of forming the film surface of the vapor deposition material on the surface of the substrate strip as the object 5a by the apparatus of the above embodiment. In such a case, the diameter of the cluster becomes clearly smaller than that in the case where no vibration is applied, especially in the initial stage of the deposition from the start of the deposition to 20 seconds, and as a result, the value of the fine surface roughness becomes small, and the frequency is reduced. The higher the frequency, the smaller the diameter of the cluster and the smaller the value of the fine surface roughness. Particularly, at 10 kHz, the cluster is small, and the fine surface roughness is It became smaller, a smooth film surface shape was obtained, and the effect of applying vibration was confirmed.

Since the natural frequency of the piezoelectric element 9a in the apparatus of the above embodiment is slightly above 7 kHz, the amplitude of the substrate strip becomes larger at 10 kHz than at other frequencies. As a result, it is estimated that the larger the amplitude of the object, the smaller the diameter of the cluster and the smaller the value of the fine surface roughness.

Further, in the graph shown in FIG. 4, the diameter of the cluster is smaller when the vibration is applied than when the vibration is not applied, and the diameter of the cluster becomes smaller as the excitation frequency is higher. It was confirmed that the higher the excitation frequency, the lower the film surface generation rate. Therefore, according to the method and apparatus of the above embodiment, the formation rate of the film surface can be controlled to optimize the formation of the deposited film.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above examples. For example, an electron beam sputtering apparatus may be used instead of an ion sputtering apparatus in the deposition film forming section. In addition, the object vibrating unit may use other vibrating means instead of the piezoelectric element, for example, a vibration source for transmitting vibration to the object from outside the sputtering container via a transmission member.

Further, as for the coupling method between the vibrating means such as a piezoelectric element and the object, other methods such as clamping may be used instead of bonding with an adhesive. The material is not limited to the above, and may be changed as appropriate.

[Brief description of the drawings]

FIG. 1A is a diagram illustrating an ion as a vapor deposition film forming unit in one embodiment of a vapor deposition film surface smoothing apparatus according to one embodiment of the present invention for implementing one embodiment of the vapor deposition film surface smoothing method of the present invention. FIG. 2 is an explanatory view schematically showing a vapor deposition process by a sputtering apparatus, and FIG. 2B is a configuration diagram showing a schematic configuration of an ion sputtering apparatus in the apparatus of the embodiment.

FIG. 2 is a configuration diagram illustrating a schematic configuration of an object vibrating unit in the apparatus of the embodiment.

FIG. 3 (a) is an AFM observation image of a substrate strip surface when vapor deposition is performed for 20 seconds without applying vibration by the apparatus of the above embodiment, and FIG. 3 (b) is an image of the above embodiment by the apparatus of the above embodiment. 5 is an image observed by AFM on the surface of a substrate strip when vapor deposition is performed for 20 seconds while vibrating at 100 kHz according to the method described above.

FIG. 4 is a graph showing a cluster diameter of a film surface formed by vapor deposition according to the method of the above embodiment in relation to a vapor deposition time and an excitation frequency.

FIG. 5 is a graph showing the fine surface roughness of a film surface formed by vapor deposition in the method of the above embodiment in relation to the vapor deposition time and the excitation frequency.

FIGS. 6A to 6C are explanatory diagrams showing three types of a process of forming a film surface by vapor deposition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cluster 2 Object 3 Monoatomic layer 4 Container 5 Anode 6 Cathode 6a Target 7 Power supply 8 Plasma 9 Object excitation part 9a Stacked piezoelectric element 9b Oscillator 9c Oscillograph

Claims (4)

[Claims] 1. A method for smoothing a surface of a vapor-deposited film, comprising: applying a vibration to the object during the formation of the vapor-deposited film on the surface of the object. 2. An evaporation film forming unit for forming an evaporation film of material particles on a surface of an object, and the object vibrates while the evaporation film forming unit generates an evaporation film on the surface of the object. And an object vibrating unit for applying the object, and a device for smoothing the surface of the deposited film. 3. The object vibrating unit includes: a piezoelectric element coupled to the object so as to excite the object; and an electric signal supplied to the piezoelectric element by supplying an electric signal to the piezoelectric element. 3. The apparatus for smoothing a surface of a vapor-deposited film according to claim 2, further comprising: an oscillator for vibrating. 4. The apparatus according to claim 2, wherein the deposition film forming section has an ion sputtering device.
An apparatus for smoothing a surface of a vapor-deposited film as described in the above.