JP2021017602A - Manufacturing method of microstructure, and manufacturing apparatus of microstructure - Google Patents

Abstract

To provide a manufacturing method of a microstructure, and a manufacturing apparatus of a microstructure, excellent in an etching rate, capable of improving throughput.SOLUTION: In a manufacturing method of a microstructure, which is a manufacturing method of the microstructure by performing etching, an IAD (ion assist deposition) device 1 is used, and etching is performed by introducing reactive gas to a plasma source 7 in a chamber 2 of the IAD device 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a microstructure and an apparatus for producing a microstructure, and more particularly to a method for producing a microstructure that has an excellent etching rate and can improve throughput.

Conventionally, a plasma generation source is attached to an etching apparatus, and it is necessary to increase the size of the matching box and coil required to generate plasma in order to increase the processing area. However, in reality, the matching box and the like could not be enlarged, the processing area was about 8 inches, and it was difficult to improve the throughput.
Specifically, in the apparatus described in Patent Document 1, it is necessary to enlarge the electrode which is the plasma source in order to increase the size of the target. Therefore, in order to cope with the increase in the size of the wafer, the plasma source other than the chamber is used. It was necessary to increase the size and increase the number. However, in order to increase the size or the number of plasma sources, it is necessary to increase the size of the matching box required to generate plasma.
Further, since the conventional etching apparatus has only an etching function, it is necessary to separately prepare a film forming apparatus when film forming is required, which also leads to a decrease in throughput.
On the other hand, in a vapor deposition apparatus based on the IAD (ion assist deposition) method, usually only argon (Ar) or oxygen (O ₂ ) can be used, so such an argon (Ar) or oxygen (O ₂ ) gas. When etching was performed using, the etching rate was very low, and etching processing was impossible.

Japanese Unexamined Patent Publication No. 2000-226649

The present invention has been made in view of the above problems and situations, and the problems to be solved are that it is not necessary to increase the size or increase the number of plasma sources, the etching rate is excellent, and the throughput is improved. It is an object of the present invention to provide a method for producing a microstructure capable of producing the same, and an apparatus for producing a microstructure.

In order to solve the above problems, the present inventor has an excellent etching rate by introducing a reactive gas into the plasma source in the chamber of the IAD apparatus and performing etching in the process of examining the cause of the above problems. We have found that it is possible to provide a method for manufacturing a microstructure that can improve the throughput, and have arrived at the present invention.
That is, the above problem according to the present invention is solved by the following means.

1. 1. It is a method of manufacturing a microstructure by etching.
A method for producing a microstructure, which comprises introducing a reactive gas into a plasma source in the chamber of the IAD apparatus and performing etching by using an IAD (ion assist deposition) apparatus.

2. 2. The method for producing a microstructure according to item 1, wherein a gas containing a chlorofluorocarbon gas or a hydrogen fluoride gas is introduced as the reactive gas.

3. 3. The method for producing a microstructure according to item 1 or 2, wherein the IAD apparatus is provided with a means for detoxifying a harmful gas derived from the reactive gas.

4. As the detoxification means, 10% or more of the surface area of the inner wall of the chamber and the members arranged in the chamber is covered with a material or Teflon (registered trademark) that detoxifies the harmful gas. The method for producing a microstructure according to the third item.

5. The method for producing a microstructure according to item 3, wherein as the detoxification means, a neutralizing material for neutralizing the harmful gas is provided in the chamber.

6. The third item, wherein as the detoxification means, a neutralizing material for neutralizing the harmful gas is applied or vapor-deposited on the inner wall of the chamber and the member arranged in the chamber. Method for manufacturing microstructures.

7. The method for producing a microstructure according to item 6, wherein the neutralizing material is deposited on the inner wall of the chamber and the member arranged in the chamber before the chamber is opened to the atmosphere.

8. The film-formed neutralizing material can be peeled off,
The method for producing a microstructure according to item 6 or 7, wherein the step of peeling off the neutralizing material adhering to the microstructure is included.

9. A detector capable of detecting hydrogen fluoride gas or chlorofluorocarbon gas in the chamber is provided.
Before opening the chamber, the concentration of the hydrogen fluoride gas or the chlorofluorocarbon gas is detected by the detector, and the concentration of the hydrogen fluoride gas or the chlorofluorocarbon gas in the chamber becomes equal to or less than a predetermined reference value. The method for producing a microstructure according to any one of items 1 to 8, wherein the door of the chamber is opened after the process.

10. The IAD apparatus is provided with a film forming source composed of an electron beam or resistance heating in the same chamber as the chamber.
Any one of items 1 to 9, wherein the IAD apparatus has a step of forming a film using the film forming source and a step of performing the etching using the plasma source. The method for producing a microstructure according to the section.

11. The microstructure has two or more multilayer films and has
The method for producing a microstructure according to any one of items 1 to 10, wherein at least one layer of the multilayer film contains silicon dioxide.

12. At the time of etching, from the grid of the plasma source of the IAD apparatus to the layer to be etched so that the selection ratio between the metal mask and the layer to be etched (etching rate of the layer to be etched / etching rate of the metal mask) is doubled or more. The distance, or the acceleration voltage and pressurizing current of the IAD apparatus, or the etching gas introduction amount, or the degree of vacuum, or any of the items 1 to 11 characterized by adjusting the introduction amount of argon gas. The method for producing a microstructure according to item 1.

13. The microstructure according to any one of items 1 to 12, wherein the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 40 cm or more at the time of etching. Production method.

14. Any of the items 1 to 13 characterized in that the set value of the IAD apparatus at the time of etching is within the range of the acceleration voltage of 300 to 1200 V and the acceleration current is within the range of 300 to 1200 mA. The method for producing a microstructure according to item 1.

15. When the volume of the chamber is 2700 L, any of the items 1 to 14 characterized in that the amount of chlorofluorocarbon gas or hydrogen fluoride gas introduced into the chamber at the time of etching is 20 sccm or more. The method for producing a microstructure according to item 1.

16. The first to fifteenth items, wherein when the volume of the chamber is 2700 L, the degree of vacuum at the time of etching is in the range of 5.0 × 10 ^-3 to 5.0 × 10 ^-1 Pa. The method for producing a microstructure according to any one of the items up to the item.

17. The item according to any one of items 1 to 16, wherein when the volume of the chamber is 2700 L, the amount of argon gas introduced into the chamber at the time of etching is 20 sccm or less. A method for manufacturing a microstructure.

18. Items 1 to 17 of the gas exhaust mechanism of the chamber are characterized in that the gas exhaust amount in the chamber is 250 L / min or less until the pressure in the chamber reaches 3.0 × 10 ⁴ Pa. The method for producing a microstructure according to any one of the items up to the item.

19. A device for manufacturing a microstructure used in the method for manufacturing a microstructure according to any one of items 1 to 18.
An apparatus for manufacturing a microstructure, which comprises introducing a reactive gas into a plasma source in a chamber of an IAD apparatus to perform etching.

According to the above means of the present invention, there is no need to increase or decrease the size or number of plasma sources, and a method for producing a microstructure and an apparatus for producing a microstructure capable of excellent etching rate and improvement in throughput are provided. be able to.
Although the mechanism of expression or the mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.
Since the IAD device is used to introduce a reactive gas into the plasma source for etching, installing the plasma source in a large vacuum chamber such as a vapor deposition machine makes it possible to substantially increase the size of the device and reduce the processing area. Since it can be increased, the throughput is improved. Further, by using not only the etching function but also the film forming source, the film forming and the etching can be performed by the same apparatus, which also leads to the improvement of the throughput. Further, by using the reactive gas, the etching rate is also increased.

Schematic diagram showing an example of an IAD device (A) is a schematic view of a dome coated with a Teflon sheet, (b) is a sectional view of (a), and (c) is a schematic view of a dome before coating a Teflon sheet. Cross-sectional view showing an example of the structure of a dielectric multilayer film Flowchart of the process of forming pores in the top layer A conceptual diagram illustrating a process of forming a particulate metal mask and forming pores in the uppermost layer.

The method for producing a microstructure of the present invention is a method for producing a microstructure by etching, which is reactive with a plasma source in the chamber of the IAD apparatus using an IAD (ion assist deposition) apparatus. It is characterized by introducing a gas and performing etching.
This feature is a technical feature common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, it is preferable to introduce a gas containing a chlorofluorocarbon gas or a hydrogen fluoride gas as the reactive gas, because a desired microstructure can be produced by etching.

It is preferable that the IAD apparatus is provided with means for detoxifying harmful gas derived from the reactive gas, and as the detoxifying means, 10 out of the inner wall of the chamber and the surface area of the member arranged in the chamber. By coating% or more with a material or Teflon that detoxifies the harmful gas, the harmful gas is detoxified, or the harmful gas adheres to the inner wall of the chamber and the members arranged in the chamber. It is preferable in that it can be prevented.

Further, as the detoxification means, it is preferable to provide a neutralizing material for neutralizing the harmful gas in the chamber. Further, as a means for detoxifying the chamber, a neutralizing material for neutralizing the harmful gas is applied or vapor-deposited on the inner wall of the chamber and the members arranged in the chamber to form a film, which is detoxified at low cost. It is preferable in that it can be done. In particular, it is preferable to form the neutralizing material by the vapor deposition before opening the chamber to the atmosphere, because it can be easily and surely detoxified.

The film-formed neutralizing material can be peeled off, and the step of peeling off the neutralizing material adhering to the microstructure can be included, even if the neutralizing material adheres to the microstructure. It is preferable in that a desired microstructure can be produced.

A detector capable of detecting the hydrogen fluoride gas or the freon gas in the chamber is provided, and before the chamber is released, the detector detects the concentration of the hydrogen fluoride gas or the freon gas in the chamber. Opening the door of the chamber after the concentration of the hydrogen fluoride gas or the freon-based gas falls below a predetermined reference value can prevent harmful gas from being discharged to the outside of the chamber. preferable.

The IAD apparatus is provided with a film forming source composed of an electron beam or resistance heating in the same chamber as the chamber, and the IAD apparatus uses the film forming source to form a film and the plasma source. It is preferable to have the step of performing the etching because a desired fine structure can be produced by forming a film after etching or by etching after forming a film.

It is preferable that the microstructure has two or more multilayer films, and at least one of the multilayer films contains silicon dioxide in terms of improving the etching rate.

At the time of etching, from the grid of the plasma source of the IAD apparatus to the layer to be etched so that the selection ratio between the metal mask and the layer to be etched (etching rate of the layer to be etched / etching rate of the metal mask) is doubled or more. It is preferable to adjust the distance, the acceleration voltage and pressurizing current of the IAD apparatus, the amount of etching gas introduced, the degree of vacuum, or the amount of argon gas introduced from the viewpoint of improving the etching rate. In particular, at the time of etching, it is preferable that the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 40 cm or more.

Since the set value of the IAD apparatus at the time of etching is within the range of the acceleration voltage of 300 to 1200 V and the acceleration current is within the range of 300 to 1200 mA, the amount of ions increases too much and the physical etching action is strong. It is preferable in that it can be prevented from becoming.

When the volume of the chamber is 2700 L, it is preferable that the amount of chlorofluorocarbon gas or hydrogen fluoride gas introduced into the chamber at the time of etching is 20 sccm or more from the viewpoint of improving the etching rate.

When the volume of the chamber is 2700 L, it is preferable that the degree of vacuum at the time of etching is in the range of 5.0 × 10 ^-3 to 5.0 × 10 ^-1 Pa from the viewpoint of improving the etching rate.

When the volume of the chamber is 2700 L, the amount of argon gas introduced into the chamber at the time of etching is set to 20 sccm or less so that the mask used for processing the fine structure is physically etched with argon gas. It is preferable in that it can be prevented from being etched and disappearing.
In the gas exhaust mechanism of the chamber, it is preferable that the gas exhaust amount in the chamber is 250 L / min or less until the pressure in the chamber reaches 3.0 × 10 ⁴ Pa. The purpose of controlling the displacement in this way is that when gas is present in the chamber, the amount of gas discharged from the gas exhaust mechanism is about 1000 L / min, and in order to cope with this displacement, an abatement machine is used. As the size increases, it is necessary to have the ability to eliminate damage according to the displacement. Therefore, by controlling the gas displacement to XX L / min or less, even in an IAD device with a large chamber, the chamber and the abatement device can always be connected, which is harmful. It is possible to prevent the gas from being exhausted into the atmosphere.

The microstructure manufacturing apparatus used in the microstructure manufacturing method of the present invention is characterized in that a reactive gas is introduced into a plasma source in the chamber of the IAD apparatus to perform etching. As a result, it is not necessary to increase the size or increase the number of plasma sources, the etching rate is excellent, and the throughput can be improved.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[Outline of Manufacturing Method of Microstructure of the Present Invention]
The method for producing a microstructure of the present invention is a method for producing a microstructure by etching, and a reactive gas is applied to a plasma source of the IAD apparatus by using an IAD (ion assist deposition) apparatus. It is characterized in that it is introduced and the etching is performed.

As the IAD apparatus, a thin-film deposition apparatus using a normal IAD method can be used. A film formation source composed of an electron beam or resistance heating is provided in the same chamber as the chamber of the apparatus, and the film formation source is used. It is preferable to carry out film formation by vapor deposition or etching using the plasma source. The order of film formation and etching is not particularly limited.

The microstructure may have one single-layer film or two or more multilayer films, but in the present invention, it is preferable to have a multilayer film. Further, it is preferable that at least one layer of the multilayer film contains silicon dioxide from the viewpoint of improving the etching rate.
Then, the surface of the single-layer film or the multilayer film arranged in the IAD apparatus is etched with the plasma source to form pores on the surface. In the case of a multilayer film, the etching forms pores that partially expose the surface of the layer adjacent to the top layer. Specifically, the microstructure according to the present invention is preferably a dielectric multilayer film described later.

When etching using the IAD apparatus, a reactive gas is introduced into a plasma source (IAD ion source described later).
As the reactive gas, it is preferable to introduce a gas containing a chlorofluorocarbon gas or a hydrogen fluoride gas from the viewpoint that a desired microstructure can be produced by etching.

Further, since harmful gas derived from the reactive gas is generated by introducing the reactive gas into the IAD apparatus and performing etching, a means (described later) for detoxifying the harmful gas is provided. , It is preferable to detoxify the harmful gas.

Hereinafter, the IAD apparatus used in the method for producing a microstructure of the present invention will be described in detail, but the present invention is not limited thereto.

[IAD device]
FIG. 1 is a schematic view showing an example of an IAD device.
The IAD apparatus 1 according to the present invention includes a dome 3 in a chamber 2, and a substrate 4 is arranged along the dome 3.
A vapor deposition source (deposition source) 5 and an IAD ion source (plasma source) 7 are arranged at the bottom of the chamber 2. Further, the gas supply unit 91 communicates with the chamber 2 via the port 91a, and the gas from the gas supply unit 91 is supplied to the IAD ion source 7. Further, the gas discharge unit 92 communicates with the chamber 2 via the port 92a. The gas exhaust mechanism according to the present invention is configured by the gas discharge unit 92, the port 92a, and the like.

<Evaporation source>
The thin-film deposition source 5 includes an electron gun or a resistance heating device that evaporates the vapor-deposited substance, and the thin-film deposition material 6 scatters from the vapor deposition source 5 toward the substrate 4 and condenses and solidifies on the substrate 4. At that time, the ion beam 8 is irradiated from the IAD ion source 7 toward the substrate 4, and the high kinetic energy of the ions is applied during the film formation to form a dense film or enhance the adhesion of the film.
Further, the IAD ion source 7 ionizes the supplied reactive gas, emits ionized gas molecules (ion beams) into the chamber 2, and the emitted ion beams are among the films formed on the substrate 4. , Etch the exposed part where the mask is not formed.

Here, the substrate 4 used in the present invention includes resins such as glass, polycarbonate resin, and cycloolefin resin, and is preferably an in-vehicle lens.

As the vapor deposition source 5, one vapor deposition source is shown in FIG. 1, but the number of vapor deposition sources 5 may be plural. By generating the vapor-deposited substance 6 from the film-forming material (deposited material) of the vapor deposition source 5 by an electron gun or resistance heating, and scattering and adhering the film-forming material to the substrate 4 (for example, a lens) installed in the chamber 2. , A layer made of a film-forming material (for example, SiO ₂ , MgF ₂ , or Al ₂ O ₃ , which is a low refractive index material described later, Ta ₂ O ₅ , TiO ₂ which is a high refractive index material described later, etc.) Is formed on the substrate 4.

Further, as will be described later, when forming the uppermost layer containing SiO ₂ in the dielectric multilayer film according to the present invention, the SiO ₂ target is arranged on the vapor deposition source 5 to form a layer containing SiO ₂ as a main component. Is preferable. In order to further improve the hydrophilic function, it is preferable to mix an element having an electronegativity smaller than Si with the SiO _2, and the elements having an electronegativity smaller than Si include sodium element, magnesium element, potassium element and Examples include calcium element and lithium.

When adding a sodium element, a sodium-containing SiO ₂ target can be prepared, placed in a vapor deposition source, and directly vapor-deposited. Alternatively, the SiO ₂ target and the sodium target may be arranged separately, and the SiO ₂ and sodium may be vapor-deposited by co-depositing. In the present invention, it is preferable to prepare a sodium-containing SiO ₂ target, place the target on a vapor deposition source, and directly vapor-deposit the target from the viewpoint of improving the sodium content accuracy.

As sodium, Na ₂ O is preferably used, as magsium, Mg O is preferably used, as potassium is preferably K ₂ O, and in the case of calcium, Ca O is preferably used, and lithium is used. In the case of, it is preferable to use Li ₂ O. Any commercially available product can be used.

<IAD ion source>
When the IAD ion source 7 forms a film on the substrate 4, the IAD ion source 7 ionizes the argon gas and oxygen gas supplied from the gas supply unit 91, and directs the ionized gas molecules (ion beam 8) toward the substrate 4. When irradiating and etching the film formed on the substrate 4 (for example, the uppermost layer containing SiO ₂ ), the reactive gas supplied from the gas supply unit 91 is ionized and the ionized ions are formed. This is a device that irradiates a beam 8 toward a film to perform etching.
The argon gas and oxygen gas are positive accumulated on the substrate in order to prevent a phenomenon in which the entire substrate is positively charged (so-called charge-up) due to the accumulation of positive ions irradiated from the ion gun on the substrate. It is also used as a neutralizer that electrically neutralizes the charge.
The neutralizer condition is preferably 1000 mA or less as an effect of preventing charge-up and reducing damage to the metal mass used for creating the structure. It is preferably in the range of 250 to 500 mA.

As the IAD ion source 7, a Kaufmann type (filament), a hollow cathode type, an RF type, a bucket type, a duoplasmatron type and the like can be applied.
By irradiating the substrate 4 with the above gas molecules from the IAD ion source 7, for example, molecules of the film-forming material evaporating from a plurality of evaporation sources can be pressed against the substrate 4, and a film having high adhesion and denseness can be formed on the substrate. A film can be formed on the 4.
Although the IAD ion source 7 is installed at the bottom of the chamber 2 so as to face the substrate 4, it may be installed at a position deviated from the facing axis.

At the time of etching, the selection ratio (etching rate of the layer to be etched / etching rate of the metal mask) between the metal mask and the layer to be etched (for example, the uppermost layer), which will be described later, is doubled or more. It is preferable to adjust the distance from the grid to the layer to be etched, the acceleration voltage and pressurizing current of the IAD apparatus, the amount of etching gas introduced, the degree of vacuum, or the amount of argon gas introduced from the viewpoint of improving the etching rate. In particular, at the time of etching, the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is preferably 40 cm or more.
Further, the set value of the ion beam at the time of etching is preferably set so that the acceleration voltage is in the range of 300 to 1200 V and the acceleration current is in the range of 300 to 1200 mA. Within this range, the amount of ions increases too much, the physical etching action becomes strong, and it is possible to prevent the mask used for etching described later from disappearing.
In the etching process, the irradiation time of the ion beam is, for example, 15 minutes when the distance from the plasma source grid of the IAD device to the layer to be etched is 40 cm, and 50 minutes when the distance from the plasma source grid of the IAD device to the layer to be etched is 100 cm. Can be.
Further, in the film forming step, the irradiation time of the ion beam can be set to, for example, 1 to 800 seconds, and the number of particles irradiated by the ion beam can be set, for example, 1 × 10 ^{13 to} 5 × 10 ¹⁷ pieces / cm ^2. it can.

The ion beam used in the etching step can be an ion beam of a chlorofluorocarbon gas or a hydrogen fluoride gas which is a reactive gas. For example, when the volume of the chamber is 2700 L, the chlorofluorocarbon gas or the hydrogen fluoride gas It is preferable that the amount of the introduced gas is 20 sccm or more. Further, it is preferable that the amount of argon gas introduced at the time of etching is 20 sccm or less because the mask used for etching can be prevented from being physically etched by the argon gas and disappearing.

Further, the ion beam used in the film forming step can be an oxygen ion beam, an argon ion beam, or an ion beam of a mixed gas of oxygen and argon. For example, the oxygen introduction amount is preferably in the range of 30 to 60 sccm and the argon introduction amount is preferably in the range of 0 to 10 sccm.
In the present invention, "sccm" is an abbreviation for standard cc / min, and is a unit indicating how many cc flowed per minute at 1 atm (atmospheric pressure 10 ¹³ hPa) and 0 ° C.

<Dome>
The dome 3 holds at least one holder 3a for holding the substrate 4, and is also called a thin-film deposition umbrella. The dome 3 has an arcuate cross section, passes through the center of a string connecting both ends of the arc, and has a rotationally symmetric shape that rotates with an axis perpendicular to the string as a rotationally symmetric axis. When the dome 3 rotates about the shaft at a constant speed, for example, the substrate 4 held by the dome 3 via the holder 3a revolves around the shaft at a constant speed.

The dome 3 can hold a plurality of holders 3a side by side in the radial direction of rotation (radial direction of revolution) and the direction of rotation (revolutionary direction). As a result, it becomes possible to simultaneously etch or form a film on a plurality of substrates 4 held by the plurality of holders 3a, and it is possible to improve the manufacturing efficiency of the element.

<Gas supply unit>
The gas supply unit 91 is for supplying gas to the IAD ion source 7. Examples of the gas supplied from the gas supply unit 91 include a reactive gas and an inert gas.
Examples of the reactive gas include carbon tetrafluoride (CF ₄ ), sulfur hexafluoride (SF ₆ ), and trifluoromethane (CHF ₃ ). Among these, chlorofluorocarbon gas or hydrogen fluoride gas is particularly used. It is preferable to contain it.
Examples of the inert gas include argon (Ar), nitrogen (N ₂ ), helium (He), krypton (Kr), neon (Ne), and a mixed gas thereof.

<Gas discharge part>
The gas discharge unit 92 is for exhausting the inside of the chamber 2. The gas discharge unit 92 exhausts the inside of the chamber 2 to a predetermined degree of vacuum.
When the volume of the chamber 2 is 2700 L, the degree of vacuum at the time of etching is preferably in the range of 5.0 × 10 ^{-3 to} 5.0 × 10 ^-1 Pa.
Further, in the gas exhaust mechanism composed of the gas discharge unit 92, the port 92a, etc., the gas exhaust amount in the chamber 2 is 250 L / min or less until the pressure in the chamber 2 becomes 3.0 × 10 ⁴ Pa. Is preferable. The purpose of controlling the displacement in this way is that when gas is present in the chamber 2, the amount of gas discharged from the gas exhaust mechanism is about 1000 L / min, and in order to cope with this displacement, a detoxifier It is necessary to increase the size of the vehicle and to have the ability to eliminate damage according to the displacement. Therefore, by controlling the gas displacement to 250 L / min or less, even in an IAD device with a large chamber, the chamber and the abatement device can always be connected, and harmful gas can be released. It is possible to prevent exhaust to the atmosphere.
Specifically, the gas displacement can be reduced to 250 L / min or less by reducing the diameter of the pipe connected to the gas discharge unit 92 and the port 92a. For example, by changing the normally used pipe having a diameter of 25 mm to a pipe having a diameter of 10 mm or less, it is possible to control the displacement in a direction of decreasing. Further, as a method of setting the pipe diameter to φ10 mm or less, it is preferable to use an orifice plate having a thickness of 1 mm and a hole of φ10 mm or less.

<Means to detoxify>
As a means for detoxifying the harmful gas (for example, a gas containing chlorofluorocarbon gas or hydrogen fluoride gas) generated by etching, the surface area of the inner wall of the chamber 2 and the surface area of the member arranged in the chamber 2 is used. Of this, 10% or more may be coated with a material or Teflon that detoxifies the harmful gas.
Examples of the member arranged in the chamber 2 include a dome 3, a vapor deposition source 5, and an IAD ion source 7.
Examples of the material for detoxifying the harmful gas include calcium carbonate and calcium oxide.
When coating with Teflon, a Teflon sheet (product name: PTFE sheet, model number: 638-17-97-01, manufactured by Tokyo Glass Instruments Co., Ltd.) can be used.
By coating the inner wall of the chamber 2 and the members arranged in the chamber 2 with a material or Teflon that detoxifies the harmful gas, the harmful gas generated in the etching process is detoxified, or the inner wall of the chamber 2 or the above It is possible to prevent harmful gas from adhering to the member.
For example, when the surface (upper surface and lower surface) of the dome 3 is coated with Teflon, it is preferable to coat the remaining holder 3a (unused holder) other than the holder 3a that holds the substrate to be vapor-deposited or etched with the Teflon sheet 3b. .. 2A is a schematic view of a dome coated with a Teflon sheet, FIG. 2B is a cross-sectional view of FIG. 2A, and FIG. 2C is a schematic view of a dome before coating a Teflon sheet. Note that FIG. 1 shows an example in which the Teflon sheet is not coated.

Further, as the detoxification means, a neutralizing material for neutralizing the harmful gas may be provided in the chamber 2. Specifically, calcium carbonate or calcium oxide may be arranged at a position in the chamber 2 that is not affected by vapor deposition or etching. This neutralizes the harmful gas and renders it harmless.
Further, as another means for detoxifying, it is harmless at low cost to apply a neutralizing material for neutralizing the harmful gas to the inner wall of the chamber 2 and the members arranged in the chamber 2 by coating or vapor deposition. It is preferable in that it can be neutralized.
Examples of the neutralizing material used for forming a film by the coating include calcium carbonate and calcium oxide, and examples of the neutralizing material used for forming a film by vapor deposition include calcium carbonate and calcium oxide.

When the neutralizing material is deposited by vapor deposition, it is possible to deposit the neutralizing material on the inner wall of the chamber and the members arranged in the chamber by vapor deposition before opening the chamber to the atmosphere to detoxify the harmful gas after etching. It is preferable in that it is effective for.

Further, the neutralizing material formed by coating or vapor deposition can be peeled off, and the step of peeling off the neutralizing material adhering to the microstructure allows the neutralizing material to adhere to the microstructure during film formation. However, it is preferable in that the neutralizing material can be removed and a desired microstructure can be produced. Examples of the peeling method include a peeling method using an etching solution, an organic solvent, and dry etching.
It is preferable that the detoxifying means is further provided in the gas discharging unit 92 as the detoxifying machine 93. As the abatement machine 93, for example, a dry etching exhaust gas treatment device (manufactured by Ube Industries, Ltd.) is preferably used.

Further, a detector 11 capable of detecting hydrogen fluoride gas or chlorofluorocarbon gas is provided in the chamber 2. The detector 11 is provided to ensure the safety of the working environment because the hydrogen fluoride gas generated in the chamber 2 may exceed the safety standard.
The detector 11 is preferably arranged so that the gas intake port faces downward. As a result, the detection accuracy of the gas concentration is improved. In the figure, the dotted arrow extending to the detector indicates the gas intake direction.
The detector 11 detects the concentration of hydrogen fluoride gas or chlorofluorocarbon gas in the chamber 2 before opening the door of the chamber 2, and after the concentration becomes equal to or less than a predetermined reference value, a control unit described later performs a control unit. Control to open the door of the chamber 2. As a result, it is possible to prevent harmful gas from being discharged to the outside of the chamber 2.
As the detector 11, for example, RIKEN Keiki GD-70D or the like can be used.
A detector capable of detecting not only hydrogen fluoride gas and chlorofluorocarbon gas but also other harmful gases may be provided.

Further, the IAD device 1 according to the present invention includes a monitor system 10. The monitor system 10 is a system that monitors the wavelength characteristics of the layer formed on the substrate 4 by monitoring the layer that evaporates from each vapor deposition source 5 and adheres to itself during vacuum film formation. With this monitor system, it is possible to grasp the optical characteristics (for example, spectral transmittance, light reflectance, optical layer thickness, etc.) of the layer formed on the substrate 4.
The monitor system 10 also includes a crystal layer thickness monitor, and can monitor the physical layer thickness of the layer formed on the substrate 4.
The monitor system 10 switches ON / OFF of a plurality of evaporation sources 5 and ON / OFF of the IAD ion source 7 according to the monitoring result of the layer, and further operates the gas supply unit 91 and the gas discharge unit 92. It also functions as a control unit that controls the opening / closing operation of the door (not shown) of the chamber 2.

[Dielectric multilayer film]
The microstructure produced by the method for producing a microstructure of the present invention preferably has two or more multilayer films, and preferably at least one layer contains silicon dioxide. The multilayer film is preferably formed on a substrate.
Specifically, the microstructure according to the present invention is preferably a dielectric multilayer film.
The dielectric multilayer film has at least one low refractive index layer and at least one high refractive index layer, and the uppermost layer farthest from the substrate is the low refractive index layer, which is the uppermost layer. The high refractive index layer arranged on the substrate side is a functional layer containing a metal oxide having a photocatalytic function, and the uppermost layer contains the silicon dioxide-containing layer, that is, a metal oxide having a hydrophilic function. It is preferably a hydrophilic layer and has pores that partially expose the surface of the functional layer.

Here, the "low refractive index layer" means a layer having a refractive index smaller than 1.7 on the d-line. The high refractive index layer means a layer having a refractive index of 1.7 or more on the d line. The substrate is an optical member made of resin or glass and may have any shape. The transmittance at an optical wavelength of 550 nm is preferably 90% or more.
Here, the "photocatalytic function" refers to the organic substance decomposition effect of the photocatalyst in the present invention. This is because when the photocatalytic TiO ₂ is irradiated with ultraviolet light, active oxygen and hydroxyl radicals (.OH radicals) are generated after electrons are emitted, and the organic substances are decomposed by the strong oxidizing power of the active oxygen and hydroxyl radicals (.OH radicals). is there. By adding a functional layer containing TiO ₂ to the multilayer film according to the present invention, it is possible to prevent organic substances and the like adhering to the optical member from contaminating the optical system as stains.

Whether or not it has a photocatalytic effect is determined by, for example, irradiating a sample colored with a pen with an integrated light amount of 20 J by UV irradiation in an environment of 20 ° C. and 80%, and gradually evaluating the color change of the pen. it can. The evaluation method of the pen is based on the information described in ISO-TC206.

Further, the "hydrophilic function" means that the water contact angle is 30 ° or less when the contact angle between the standard liquid (pure water) and the uppermost layer surface is measured according to the method specified by JIS R3257. This is called "hydrophilicity", and is preferably 15 ° or less. In particular, the case where the temperature is 15 ° or less is defined as "superhydrophilic" in the present invention.

Specific measurement conditions are such that at a temperature of 23 ° C. and a humidity of 50% RH, about 10 μL of pure water, which is the standard liquid, is dropped onto the sample, and the G-1 apparatus manufactured by Elma Co., Ltd. is used to perform 5 locations on the sample. Measure and obtain the average contact angle from the average of the measured values. The time until the contact angle measurement is measured within 1 minute after the standard liquid is dropped.

FIG. 3 is a cross-sectional view showing an example of the structure of the dielectric multilayer film. However, the number of layers of the low refractive index layer and the high refractive index layer is an example, and the number of layers is not limited to this. Further, another thin film may be formed between the uppermost layer and the functional layer and the uppermost layer as long as the effect of the present invention is not impaired.

The dielectric multilayer film 100 includes, for example, a high refractive index layer 103 having a refractive index higher than that of the glass substrate 101 constituting the lens, and a low refractive index having a refractive index lower than that of the high refractive index layer. It has layers 102 and 104. Further, the uppermost layer 106 farthest from the substrate 101 is a low refractive index layer, and the high refractive index layer adjacent to the uppermost layer is a functional layer 105 containing a metal oxide having a photocatalytic function as a main component. The uppermost layer has a pore 30 that partially exposes the surface of the functional layer and a microstructure 31 excluding the pores, and constitutes a multilayer film 107.
With this configuration, the photocatalytic function (self-cleaning property) of the functional layer 105 can be exhibited on the surface of the multilayer film via the uppermost layer 106. Here, the microstructure 31 excluding the pores means that the uppermost layer containing a metal oxide having a hydrophilic function is etched by the IAD apparatus 1 according to the present invention using a metal mask described later to form pores. The remaining structural part.

The dielectric multilayer film preferably has a multilayer structure in which these high refractive index layers and low refractive index layers are alternately laminated.
The number of layers to be laminated is not particularly limited, but it is preferable that the number of layers is 12 or less from the viewpoint of maintaining high productivity and obtaining an antireflection layer. That is, the number of layers depends on the required optical performance, but the reflectance of the entire visible region can be reduced by stacking about 3 to 8 layers, and the upper limit is 12 layers or less. However, it is preferable in that the stress of the film becomes large and the film can be prevented from peeling off.
The dielectric multilayer film according to the present invention has an average light reflectance of 1% or less with respect to light incident from the normal direction in a region having a light wavelength of 450 to 780 nm, so that an image captured as an in-vehicle lens can be visually recognized. It is preferable from the viewpoint of improving the property. In the present invention, the multilayer film is formed on the substrate 101 to form an optical member. The light reflectance can be measured by a reflectance measuring machine (USPM-RUIII) (manufactured by Olympus Corporation).

The material used for the high refractive index layer and the low refractive index layer according to the present invention is preferably, for example, oxides such as Ti, Ta, Nb, Zr, Ce, La, Al, Si, and Hf, or these. Oxidized compounds in combination with MgF ₂ and MgF ₂ are suitable. Further, by stacking a plurality of layers of different dielectric materials, it is possible to add a function of reducing the reflectance of the entire visible region.

The low refractive index layer is made of a material having a refractive index smaller than 1.7, and in the present invention, it is preferable that the layer contains SiO ₂ as a main component. However, it is also preferable to contain other metal oxides, and it is also preferable from the viewpoint of light reflectance that it is a mixture of SiO ₂ and a part of Al ₂ O ₃ or Mg F ₂ .

The high refractive index layer is composed of a material having a refractive index of 1.7 or more, for example, a mixture of an oxide of Ta and an oxide of Ti, and other oxides of Ti, an oxide of Ta, and an oxide of La. It is preferably a mixture of and Ti oxides. The metal oxide used in the high refractive index layer preferably has a refractive index of 1.9 or more. In the present invention, it is preferably Ta ₂ O ₅ or TiO ₂ , and more preferably Ta ₂ O ₅ .

The overall thickness of the dielectric multilayer film is not particularly limited, but is preferably 500 nm or less, more preferably 50 to 500 nm, from the viewpoint of antireflection performance. When the thickness is 50 nm or more, the optical characteristics of antireflection can be exhibited, and when the thickness is 500 nm or less, the error sensitivity is lowered and the good quality ratio of the spectral characteristics of the lens can be improved.

The uppermost layer 106 is preferably a layer containing SiO ₂ as a main component, and the uppermost layer preferably contains an element having an electronegativity smaller than Si, and in particular, the sodium element is 0. It is preferably contained in the range of 5 to 10% by mass. A more preferable content range is in the range of 1.0 to 5.0% by mass. By containing the element, it is possible to maintain superhydrophilicity for a long time.

Here, the "main component" means that 51% by mass or more of the total mass of the uppermost layer is SiO ₂ , preferably 70% by mass or more, and particularly preferably 90% by mass or more. To say.

The composition analysis of the uppermost layer can be measured using the following X-ray photoelectron spectroscopy analyzer (XPS).

(XPS composition analysis)
-Device name: X-ray photoelectron spectroscopy analyzer (XPS)
-Device model: Quantera SXM
・ Equipment manufacturer: ULVAC-PHI ・ Measurement conditions: X-ray source: Monochromatic AlKα ray 25W-15kV
・ Vacuum degree: 5.0 × ^10-8 Pa
Depth direction analysis is performed by argon ion etching. For data processing, MultiPak manufactured by ULVAC-PHI is used.

Further, the film density of the uppermost layer is preferably 98% or more, and preferably in the range of 98 to 100% from the viewpoint of salt water resistance and superhydrophilicity.
In particular, it is preferable that the uppermost layer is formed by ion-assisted vapor deposition using the IAD apparatus 1 according to the present invention from the viewpoint of further increasing the film density, and at that time, heat of 300 ° C. or higher is applied. Is more preferable.

With this configuration, since the uppermost layer of the multilayer film has a high film density, it is possible to provide a multilayer film having excellent surface salt water resistance and capable of maintaining a low water contact angle for a long period of time in a high temperature and high humidity environment.

<Measurement method of film density>
Here, in the present invention, the "membrane density" means the space filling density and is defined as the value p represented by the following formula (1). The film density is measured before etching.

Space filling density p = (volume of solid part of membrane) / (total volume of membrane) ... (1)
Here, the total volume of the membrane is the sum of the volume of the solid portion of the membrane and the volume of the micropore portion of the membrane.

The film density can be measured by the following method.

(I) A layer containing SiO ₂ and a sodium element (top layer according to the present invention) on a substrate made of white plate glass BK7 (manufactured by SCHOTT) (φ (diameter) = 30 mm, t (thickness) = 2 mm). The light reflectance of the uppermost layer is measured by forming only (corresponding to). On the other hand, (ii) thin film calculation software (Essential Macleod) (SIGMA KOKI Co., Ltd.) calculates the theoretical value of the light reflectance of a layer made of the same material as the top layer. Then, the film density of the uppermost layer is specified by comparing the theoretical value of the light reflectance calculated in (ii) with the light reflectance measured in (i). The light reflectance can be measured by a reflectance measuring machine (USPM-RUIII) (manufactured by Olympus Corporation).

In FIG. 3, the arrangement of the functional layer 105 containing a metal oxide having a photocatalytic function as a main component in the adjacent layer of the uppermost layer 106 can effectively exert the photocatalytic function, and the metal oxide having a photocatalytic effect and a photoactive effect. Is a preferred embodiment because it can remove surface organic substances, which are the main components of dirt, and contribute to maintaining the superhydrophilicity of the uppermost layer 106.

It is preferable that the metal oxide having a photocatalytic function is TiO ₂ because it has a high refractive index and can reduce the light reflectance of the dielectric multilayer film.

The dielectric multilayer film according to the present invention shown in FIG. 3 has a low refractive index layer, a high refractive index layer, and an uppermost layer 106 laminated on the substrate 101 to form a multilayer film, but both sides of the substrate 101. The uppermost layer may be formed on the surface. That is, it is preferable that the uppermost layer is on the side exposed to the external environment, but the influence of the internal environment is prevented not on the exposed side, for example, on the inside opposite to the exposed side. In order to do so, an uppermost layer may be formed. Further, the dielectric multilayer film according to the present invention can be applied to optical members such as antireflection members and heat shield members in addition to lenses.
Further, the uppermost layer 106 preferably has pores having a specific shape by being etched using the IAD apparatus 1 according to the present invention described above.

[Manufacturing method of dielectric multilayer film]
The method for producing a dielectric multilayer film according to the present invention includes a step of forming at least one low refractive index layer and at least one high refractive index layer on a substrate, and a photocatalyst function as the high refractive index layer. A step of forming a functional layer containing a metal oxide as a main component, a step of forming a hydrophilic layer containing a metal oxide having a hydrophilic function as the uppermost layer farthest from the substrate, and a step of forming the uppermost layer on the uppermost layer. It is preferable to include a step of forming pores that partially exposes the surface of the functional layer.

In the step of forming the low refractive index layer and the high refractive index layer on the substrate, a thin film such as a metal oxide used for the high refractive index layer and the low refractive index layer is formed. As a method for forming the high refractive index layer and the low refractive index layer, a vacuum vapor deposition method, an ion beam vapor deposition method, an ion plating method, etc. for a vapor deposition system, a sputtering method, an ion beam sputtering method, a magnetron sputtering method, etc. However, in the present invention, the ion-assisted vapor deposition method (IAD method) or the sputtering method is particularly preferable.

In the step of forming the uppermost layer, a hydrophilic layer containing a metal oxide having a hydrophilic function is formed as the uppermost layer. As a method for forming the uppermost layer, it is preferable to form a high-density film by using the IAD method.
It is preferable that any one of the layers of the multilayer film according to the present invention is formed by the IAD method, and it is more preferable that all the layers are formed by the IAD method. The film formation by the IAD method can further improve the scratch resistance of the entire microstructure.

In the step of forming pores in the uppermost layer, pores are formed in the uppermost layer so as to partially expose the surface of the functional layer.
The method of forming pores on the surface of the uppermost layer is shown below.
As shown in FIG. 3, the uppermost layer 106 has a plurality of pores 30 for exhibiting a photocatalytic function in the functional layer 105 which is an adjacent high refractive index layer.
The pores 30 are formed by etching with the IAD apparatus described above.

Hereinafter, a step of forming pores in the uppermost layer will be described.
FIG. 4 is a flowchart of a process of forming pores in the uppermost layer, and FIG. 5 is a conceptual diagram illustrating a process of forming a particulate metal mask to form pores in the uppermost layer.

In FIG. 4, for example, a low refractive index layer and a high refractive index layer as a multilayer film are alternately laminated on a glass base material (glass substrate) (multilayer film forming step: step S11). However, in step S11, a layer of the multilayer film excluding the uppermost layer 106 and the functional layer 105 is formed. That is, even a low refractive index layer adjacent to the lower side of the functional layer 105 is formed. The multilayer film is formed by using various vapor deposition methods, IAD methods, sputtering methods, and the like. Depending on the configuration of the dielectric multilayer film 100, the formation of the multilayer film in step S11 may be omitted.

Then, as step 12, the functional layer 105 is formed, and then as step 13, the uppermost layer 106 is formed. As a forming method, it is preferable to form a film by an IAD method or a sputtering method, and it is more preferable to use an IAD method.

After the uppermost layer forming step, a metal mask 50 is formed on the surface of the uppermost layer 106 (mask forming step: step S14).
As shown in FIG. 5A, the metal mask 50 is formed in the form of particles on the surface of the uppermost layer 106. As a result, the nano-sized metal mask 50 can be formed on the uppermost layer 106. As shown in FIG. 5D, the metal mask 50 may be formed in the shape of veins. Further, as shown in FIG. 5 (E), the metal mask 50 may be formed in a porous shape.

The metal mask 50 is composed of a metal portion 50a and an exposed portion 50b. The film thickness of the metal mask 50 is in the range of 1 to 30 nm. Although it depends on the film forming conditions, for example, when the metal mask 50 is formed so that the film thickness is 2 nm by using a vapor deposition method, the metal mask 50 tends to be in the form of particles. Further, for example, when the metal mask 50 is formed to have a film thickness of 12 to 15 nm by using a vapor deposition method, the metal mask 50 tends to have a vein shape. Further, when a film is formed so as to have a film thickness of 10 nm by using, for example, a sputtering method, the metal mask 50 tends to have a porous shape. By forming a metal having a thickness in the above range, the optimum metal mask 50 having a particle shape, a vein shape, or a porous shape can be easily formed.
The metal mask 50 is formed of, for example, Ag, Al, or the like, and is preferably Ag from the viewpoint of controlling the shape of the pores.

Next, a plurality of pores 30 are formed in the uppermost layer 106 (pore formation step: step S15). As shown in FIG. 5B, etching is performed by introducing a reactive gas into the IAD apparatus (IAD ion source) of the present invention.
The IAD apparatus of the present invention may be used for the above-mentioned film formation of the multilayer film and the film formation of the metal mask 50.
In the pore forming step, a plurality of pores are formed by using the material of the uppermost layer 106, specifically, a reactive gas that reacts with SiO ₂ . In this case, SiO _{2 of the} uppermost layer 106 can be scraped without damaging the metal mask 50.
Examples of the reactive gas include the above-mentioned fluorocarbon gas and hydrogen fluoride gas.
As a result, a plurality of pores 30 that expose the surface of the functional layer 105 are formed in the uppermost layer 106. That is, the uppermost layer 106 corresponding to the exposed portion 50b of the metal mask 50 was etched to form the pores 30 and the microstructure 31 of SiO ₂ which is the uppermost layer forming material, and the surface of the functional layer 105 was partially exposed. It becomes a state.

After the pore forming step, as shown in FIG. 5C, the metal mask 50 is removed (mask removing step: step S16). Specifically, the metal mask 50 is removed by wet etching with acetic acid or the like. Further, the metal mask 50 may be removed by dry etching using, for example, Ar or O ₂ as an etching gas in the IAD apparatus of the present invention.
If the metal mask 50 is etched using the IAD device, a series of steps from the formation of the multilayer film, the formation of pores, and the etching of the metal mask 50 can be performed in the same IAD device.
Through the above steps, a dielectric multilayer film 100 having a plurality of pores 30 in the uppermost layer 106 can be obtained.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, the operation was performed at room temperature (25 ° C.) unless otherwise specified. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass", respectively.

・ Example 1
[Preparation of dielectric multilayer film (microstructure) 1]
A low refractive index layer using SiO ₂ (Merck) on a glass substrate TAFD5G (HOYA Co., Ltd .: refractive index 1.835), OA600 (manufactured by Canon Optron Co., Ltd .: Ta ₂ O ₅ , TiO, High-refractive index layers using (a mixture of Ti ₂ O ₅ ) were laminated from layer numbers 1 to 3 in Table I to a predetermined thickness using the IAD method under the following conditions. Next, as the functional layer (layer number 4) and the uppermost layer (layer number 5) using TiO ₂ , the uppermost layer was formed by vapor deposition so that the sodium content was 5% by mass by the IAD method. A dielectric multilayer film before forming the pores having the number of layers 5 described in I was obtained.

<Film formation conditions>
(Conditions in the chamber)
Heating temperature 370 ° C
Starting vacuum 1.33 × 10 ^-3 Pa
(Evaporation source of film-forming material)
Electron gun

<Formation of low refractive index layer, high refractive index layer, functional layer and top layer>
Film formation material for low refractive index layer: SiO ₂ (Canon Optron trade name SiO ₂ )
The above-mentioned base material is installed in an IAD vacuum vapor deposition apparatus, the film-forming material is loaded into the first evaporation source, and the film-forming material is vapor-deposited at a film-forming rate of 3 Å / sec, and the thickness is 31.7 nm and 34. A 6 nm low refractive index layer (layer 1 and layer 3) was formed.

In the IAD method, an acceleration voltage of 1200 V, an acceleration current of 1000 mA, and a neutralization current of 1500 mA were used, and an apparatus of OPTORUN's RF ion source "OIS One" was used. IAD introduced gas was carried out _O 2 50 sccm, Ar gas 10 sccm, under the condition of the neutral gas Ar10sccm.

High-refractive index layer film-forming material: Ta ₂ O ₅ (Canon Optron trade name OA-600)
The film-forming material was loaded into the second evaporation source and vapor-deposited at a film-forming rate of 3 Å / sec to form a high-refractive index layer (layer 2) having a thickness of 30 nm on the low-refractive index layer. The formation of the high refractive index layer was similarly carried out by the IAD method and heating conditions at 370 ° C.

Film film material for functional layer: TiO ₂ (Fuji Titanium Industry Co., Ltd. product name TOP (Ti ₃ O ₅ ))
The above-mentioned base material is installed in a vacuum vapor deposition apparatus, the film-forming material is loaded into a third evaporation source, vapor deposition is carried out at a film-forming rate of 3 Å / sec, and a functional layer having a thickness of 113 nm is placed on the low refractive index layer. (Layer 4) was formed. The functional layer was similarly formed by the IAD method and heating conditions at 370 ° C.

The top layer of the film forming materials: SiO ₂ and _Na 2 O (Ltd. Toshima Seisakusho trade name SiO ₂ -Na ₂ O) at a mass ratio of 95: The mixed particles were prepared in 5.

The above-mentioned base material is installed in a vacuum vapor deposition apparatus, the film-forming material is loaded into a fourth evaporation source, vapor deposition is carried out at a film-forming rate of 3 Å / sec, and an uppermost layer (layer) having a thickness of 88 nm is placed on the functional layer. 5) was formed. The functional layer was similarly formed by the IAD method and heating conditions at 370 ° C.

The layer thickness (film thickness) of each layer was measured by the following method.

(Measurement of layer thickness)
The layer thickness was measured by the following method.

(1) TiO ₂ and SiO ₂ are formed in advance on a white plate glass substrate with a film thickness of 1/4 λ (λ = 550 nm), and the spectral reflectance is measured.

(2) When each layer was formed on the TiO ₂ and SiO ₂ films under the above-mentioned film forming conditions, the spectral reflectance was measured, and the refractive index and layer thickness of the layer were calculated from the amount of change. To do.

The composition analysis of the uppermost layer was measured using the following X-ray photoelectron spectroscopy analyzer (XPS).

(XPS composition analysis)
-Device name: X-ray photoelectron spectroscopy analyzer (XPS)
-Device model: Quantera SXM
・ Equipment manufacturer: ULVAC-PHI ・ Measurement conditions: X-ray source: Monochromatic AlKα ray 25W-15kV
・ Vacuum degree: 5.0 × ^10-8 Pa
Depth direction analysis is performed by argon ion etching. For data processing, MultiPak manufactured by ULVAC-PHI was used.

The light reflectance was measured with an ultraviolet visible near infrared spectrophotometer V-670 manufactured by JASCO Corporation at a light wavelength of 587.56 nm (d line).

(Measurement of refractive index on line d)
The refractive index shown in Table I is calculated by forming each layer of the multilayer film as a single layer and measuring the light reflectance on the d line using a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation. .. The refractive index of the layer obtained by adjusting the refractive index so as to fit the actually measured light reflectance data was specified using thin film calculation software (Essential Macleod) (Sigma Kouki Co., Ltd.).

<Pore formation in the uppermost layer>
After forming the uppermost layer (layer 5), according to the pore forming method shown in FIGS. 3 and 4, the mask material is Ag, the mask film is vapor-deposited, the metal mask thickness (for example, Ag) is 39 nm, and further. Substance H4 (Merck, a mixture of Ta ₂ O ₅ and La ₂ O ₅ ) 0.5 nm was formed on a metal mask, and the mask shape was leaf vein-shaped, and pores were formed under the following etching conditions.
(Etching conditions)
IAD device: NIS-175 (manufactured by Syncron)
Chamber size: 2700L
Etching gas: CHF ₃
Etching gas introduction amount: 100 sccm
Etching time: 10 minutes Acceleration voltage of IAD device: 500V
Acceleration current of IAD device: 500mA
Chamber vacuum: 7.0 × ^10-2 Pa Gas introduction Ar gas introduction amount: 0 sccm
Distance from the grid of the plasma source of the IAD device to the layer to be etched: 40 cm (selection ratio between the uppermost layer to be etched and the metal mask (etching rate of the layer to be etched / etching rate of the metal mask) is more than doubled. .)

<Peeling the mask>
After forming the pores, the mask material Ag was peeled off by irradiating O ₂ plasma with the IAD apparatus to prepare a dielectric multilayer film 1. The peeling was performed under the following peeling condition 1.
(Mask peeling condition 1)
IAD device: NIS-175 (manufactured by Syncron)
Chamber size: 2700L
Etching gas: O ₂ , Ar
Etching gas introduction amount: 50 sccm (O ₂ ), 10 sccm (Ar)
Etching time: 10 minutes Acceleration voltage of IAD device: 1000V
Acceleration current of IAD device: 1000mA
Chamber vacuum: 3.0 x 10 ^-2 Pa
Ar gas introduction amount: 10 sccm

Even when the mask was peeled under the following peeling condition 2, Ag could be peeled in the same manner as when the mask was peeled under the peeling condition 1, and the dielectric multilayer film 1 could be produced.
(Mask peeling condition 2)
The mask material Ag was peeled off by immersing in the following chemicals for 1 minute.
Chemicals: Model number SEA-5 (manufactured by Hayashi Junyakusha)

[Preparation of dielectric multilayer film 2]
In the formation of the pores of the uppermost layer in the production of the dielectric multilayer film 1, the dielectric multilayer film 2 is similarly formed except that the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 100 cm as an etching condition. Was produced.

[Preparation of dielectric multilayer film 3]
In the production of the dielectric multilayer film 1, as a detoxification means for detoxifying harmful gas, 10% or more of the surface area of the inner wall of the chamber of the IAD apparatus and the members arranged in the chamber is made of a Teflon sheet (product name:: The dielectric multilayer film 3 was produced in the same manner except that it was coated with a PTFE sheet, model number: 638-17-97-01, manufactured by Tokyo Glass Instruments Co., Ltd.).

[Preparation of dielectric multilayer film 4]
In the production of the dielectric multilayer film 3, as the detoxification means, in addition to the coating of the Teflon sheet, a neutralizing material (product name: calcium carbonate, especially in the upper part in the chamber where HF gas tends to accumulate). The dielectric multilayer film 4 was produced in the same manner except that (manufactured by Shiraishi Calcium Co., Ltd.) was installed.

[Preparation of dielectric multilayer film 5]
In the production of the dielectric multilayer film 4, as the detoxification means, in addition to coating the Teflon sheet and installing the neutralizing material, a neutralizing material (product) is applied to the inner wall of the chamber and the members arranged in the chamber. A dielectric multilayer film 5 was produced in the same manner except that a film was formed by applying (name: calcium carbonate, manufactured by Shiraishi Calcium).

After etching, using an HF gas concentration meter (GD-70D, manufactured by RIKEN Keiki Co., Ltd.), it was confirmed that the HF gas concentration in the etched chamber was 1.0 ppm or less in the production of the dielectric multilayer film 5. Since it was completed, the door of the chamber was opened and the sample was taken out.

[Preparation of dielectric multilayer films 6 to 16]
In the preparation of the dielectric multilayer film 1, the dielectric multilayer films 6 to 16 were produced in the same manner except that the etching conditions and the detoxification means were changed as shown in Table II below.

[Evaluation]
<Etching rate>
For the etching rate, the etching rate was calculated from the difference in film thickness before and after etching in the etching step (pore formation of the uppermost layer) at the time of producing each dielectric multilayer film.
The film thickness difference was calculated from a film thickness simulation using a spectral reflectance measuring machine.
Spectral reflectance measuring machine: USPM-RUIII manufactured by Olympus
(Evaluation criteria)
⊚: 10 nm / min or more ○: 3 nm / min or more and less than 10 nm / min Δ: 1 nm / min or more and less than 3 nm / min ×: less than 1 nm / min

<Damage to mask>
Damage to the mask was evaluated by the residual film thickness of the metal mask due to etching during the formation of pores in the uppermost layer. The film thickness was evaluated as good when the film thickness state at the initial stage of etching could be maintained. The remaining amount of the mask was calculated by simulating the film thickness from a spectral reflectance measuring machine.
◯: Residual film thickness of mask is 10 nm or more Δ: Residual film thickness of mask is 3 nm or more and less than 10 nm ×: Residual film thickness of mask is less than 3 nm

<Pore processing state of microstructure>
The microstructure was evaluated based on the pore-processed state of a specific uneven shape constituting the uppermost layer. As for the processed state, the uneven shape processed with pores was ranked according to the following criteria.
(Evaluation criteria)
◯: Root mean square root height Sq of pores of microstructure is 10 nm or more Δ: Root mean square root height Sq of pores of microstructure is 1 nm or more and less than 10 nm ×: Root mean square root of pores of microstructure Height Sq is less than 1 nm The root mean square height Sq was measured for the height of the pores of the microstructure using the following interatomic force microscope (AFM).
Equipment: Bruker's Dimension Icon
Probe: Bruker Silicon Probe Model RTESPA-150
Measurement mode: Peak Force Tapping
Measurement point: Pore part of the uppermost layer Analysis: The root mean square height Sq (nm) of the captured image is measured using software manufactured by BRUKER.

<Concentration of HF gas in the chamber>
After the pressure in the chamber reached 1.0 × ^10-5 Pa after the mask was peeled off, the HF gas concentration was measured using the following HF gas detector, and 2 minutes after the start of measurement. The concentration value of was measured.
Equipment: RIKEN Keiki Co., Ltd. GD-70D

As shown in the above results, by using the method for producing a microstructure of the present invention, it is possible to improve the etching rate and reduce damage to the mask as compared with the method for producing a comparative example, and obtain a desired microstructure. It turns out that it can be manufactured. Further, when the detoxifying means is used (dielectric multilayer film 3 to 5), the concentration of HF gas in the chamber is clearly lower than that when the detoxifying means is not used (dielectric multilayer film 1), which is harmless. It turns out that it is effective for conversion.

1 IAD device 2 Chamber 3 Dome 3a Holder 3b Teflon sheet 4 Substrate 5 Thin film deposition source (deposition source)
7 IAD ion source (plasma source)
10 Monitor system (control unit)
11 Detector 91 Gas supply unit 92 Gas discharge unit 93 Abatement machine 30 Pore 31 Microstructure excluding pores 50 Metal mask 50a Metal part 50b Exposed part 100 Dielectric multilayer film (microstructure)
101 Substrate 102, 104 Low refractive index layer 103 High refractive index layer 105 Functional layer 106 Top layer

Claims (19)

It is a method of manufacturing a microstructure by etching.
A method for producing a microstructure, which comprises introducing a reactive gas into a plasma source in the chamber of the IAD apparatus and performing etching by using an IAD (ion assist deposition) apparatus. The method for producing a microstructure according to claim 1, wherein a gas containing a chlorofluorocarbon gas or a hydrogen fluoride gas is introduced as the reactive gas. The method for producing a microstructure according to claim 1 or 2, wherein the IAD apparatus is provided with means for detoxifying a harmful gas derived from the reactive gas. As the detoxification means, 10% or more of the surface area of the inner wall of the chamber and the members arranged in the chamber is coated with a material or Teflon (registered trademark) that detoxifies the harmful gas. The method for producing a microstructure according to claim 3. The method for producing a microstructure according to claim 3, wherein as the detoxification means, a neutralizing material for neutralizing the harmful gas is provided in the chamber. The third aspect of claim 3, wherein as the detoxification means, a neutralizing material for neutralizing the harmful gas is applied or vapor-deposited on the inner wall of the chamber and the member arranged in the chamber. How to manufacture microstructures. The method for producing a microstructure according to claim 6, wherein the neutralizing material is deposited on the inner wall of the chamber and the member arranged in the chamber before the chamber is opened to the atmosphere. The film-formed neutralizing material can be peeled off,
The method for producing a microstructure according to claim 6 or 7, wherein the step of peeling off the neutralizing material adhering to the microstructure is included. A detector capable of detecting hydrogen fluoride gas or chlorofluorocarbon gas in the chamber is provided.
Before opening the chamber, the concentration of the hydrogen fluoride gas or the chlorofluorocarbon gas is detected by the detector, and the concentration of the hydrogen fluoride gas or the chlorofluorocarbon gas in the chamber becomes equal to or less than a predetermined reference value. The method for producing a microstructure according to any one of claims 1 to 8, wherein the door of the chamber is opened after the process. The IAD apparatus is provided with a film forming source composed of an electron beam or resistance heating in the same chamber as the chamber.
Any one of claims 1 to 9, wherein the IAD apparatus includes a step of forming a film using the film forming source and a step of performing the etching using the plasma source. The method for producing a microstructure according to the item. The microstructure has two or more multilayer films and has
The method for producing a microstructure according to any one of claims 1 to 10, wherein at least one layer of the multilayer film contains silicon dioxide. At the time of etching, from the grid of the plasma source of the IAD apparatus to the layer to be etched so that the selection ratio between the metal mask and the layer to be etched (etching rate of the layer to be etched / etching rate of the metal mask) is doubled or more. Any of claims 1 to 11, characterized in that the distance, the acceleration voltage and pressurizing current of the IAD apparatus, the etching gas introduction amount, the degree of vacuum, or the argon gas introduction amount is adjusted. The method for producing a microstructure according to item 1. The microstructure according to any one of claims 1 to 12, wherein the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 40 cm or more at the time of etching. Production method. Any of claims 1 to 13, wherein the set value of the IAD apparatus at the time of etching is within the range of the acceleration voltage of 300 to 1200 V and the acceleration current is within the range of 300 to 1200 mA. The method for producing a microstructure according to item 1. Any of claims 1 to 14, wherein when the volume of the chamber is 2700 L, the amount of chlorofluorocarbon gas or hydrogen fluoride gas introduced into the chamber at the time of etching is 20 sccm or more. The method for producing a microstructure according to item 1. Claims ^{1 to 1} , wherein when the volume of the chamber is 2700 L, the degree of vacuum at the time of etching is in the range of 5.0 × 10 ^-3 to 5.0 × 10 ^-1 Pa. The method for producing a microstructure according to any one of up to 15. The method according to any one of claims 1 to 16, wherein when the volume of the chamber is 2700 L, the amount of argon gas introduced into the chamber at the time of etching is 20 sccm or less. A method for manufacturing a microstructure. The first to claims of the gas exhaust mechanism of the chamber are characterized in that the gas exhaust amount in the chamber is 250 L / min or less until the pressure in the chamber becomes 3.0 × 10 ⁴ Pa. The method for producing a microstructure according to any one of up to 17. A device for manufacturing a microstructure used in the method for manufacturing a microstructure according to any one of claims 1 to 18.
An apparatus for manufacturing a microstructure, which comprises introducing a reactive gas into a plasma source in a chamber of an IAD apparatus to perform etching.

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