CN112239843A

CN112239843A - Method for manufacturing fine structure and apparatus for manufacturing fine structure

Info

Publication number: CN112239843A
Application number: CN202010685323.4A
Authority: CN
Inventors: 水町靖; 多田一成; 粕谷仁一
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 2019-07-17
Filing date: 2020-07-16
Publication date: 2021-01-19
Also published as: TW202111805A; TWI750642B; JP2021017602A

Abstract

The invention provides a method and an apparatus for manufacturing a fine structure, which have excellent etching rate and can improve productivity. A method for manufacturing a fine structure by etching, characterized in that an IAD (ion assisted deposition) apparatus (1) is used, and a reactive gas is introduced into a plasma source (7) in a chamber (2) of the IAD apparatus (1) to perform etching.

Description

Method for manufacturing fine structure and apparatus for manufacturing fine structure

Technical Field

The present invention relates to a method and an apparatus for manufacturing a fine structure, and more particularly, to a method and the like for manufacturing a fine structure, which have an excellent etching rate and can improve productivity.

Background

Conventionally, a plasma generation source is mounted in an etching apparatus, and a matching box and a coil required for generating plasma are required to be increased in order to increase a processing area. However, in practice, the matching box or the like cannot be increased, the processing area is about 8 inches, and it is difficult to improve the productivity.

Specifically, in the apparatus described in patent document 1, since it is necessary to increase the size of the electrode as the plasma source in order to increase the size of the target, it is necessary to increase the size of the plasma source and increase the number of plasma sources in addition to the chamber in order to cope with the increase in the size of the wafer. However, in order to increase the size of the plasma source and increase the number of the plasma sources, it is necessary to increase the size of the matching box required for generating the plasma.

Further, since the conventional etching apparatus has only an etching function, when film formation is necessary, it is necessary to separately prepare a film forming apparatus, which also leads to a reduction in productivity.

On the other hand, in a vapor deposition apparatus using an IAD (ion assisted deposition) method, only argon (Ar) or oxygen (O) is generally used₂) Therefore, such argon (Ar) or oxygen (O) is used₂) In the case where the gas is used for etching, the etching rate is very low, and etching cannot be performed.

Patent document 1: japanese patent laid-open No. 2000-226649

Disclosure of Invention

The present invention has been made in view of the above problems and circumstances, and an object of the present invention is to provide a method and an apparatus for manufacturing a fine structure, which are capable of improving productivity without increasing the size of a plasma source and increasing the number of plasma sources.

The present inventors have studied the cause of the above problems and the like in order to solve the above problems, and have found that a method for manufacturing a fine structure, which has an excellent etching rate and can improve productivity, can be provided by introducing a reactive gas into a plasma source in a chamber of an IAD apparatus and etching the reactive gas, and have completed the present invention.

That is, the above object of the present invention is achieved by the following means.

1. A method for manufacturing a fine structure, characterized in that,

is a method for manufacturing a fine structure by etching,

using an IAD (ion assisted deposition) apparatus, a reactive gas is introduced into a plasma source in a chamber of the IAD apparatus and etching is performed.

2. The method of manufacturing a fine structure according to item 1, characterized in that,

the reactive gas is a gas containing a freon gas or a hydrogen fluoride gas.

3. The method of manufacturing a fine structure according to claim 1 or 2, characterized in that,

the IAD apparatus is provided with a means for detoxifying a harmful gas derived from the reactive gas.

4. The method of manufacturing a fine structure according to item 3, characterized in that,

as means for detoxifying, 10% or more of the surface area of the inner wall of the chamber and the surface area of the member disposed in the chamber are covered with a material or polytetrafluoroethylene (registered trademark) for detoxifying the harmful gas.

5. The method of manufacturing a fine structure according to item 3, characterized in that,

as a means for performing the detoxification, a neutralizing material for neutralizing the harmful gas is provided in the chamber.

6. The method of manufacturing a fine structure according to item 3, characterized in that,

as means for performing the detoxification, a neutralizing material for neutralizing the harmful gas is formed by coating or vapor deposition on the inner wall of the chamber and a member disposed in the chamber.

7. The method of manufacturing a fine structure according to item 6, characterized in that,

before the chamber is opened to the atmosphere, the neutralizing material is formed on the inner wall of the chamber and the members disposed in the chamber by vapor deposition.

8. The method of manufacturing a fine structure according to claim 6 or 7, characterized in that,

the neutralizing material after film formation can be peeled off,

the method comprises a step of peeling off the neutralizing material adhered to the fine structure.

9. The method of manufacturing a fine structure according to any one of claims 1 to 8, characterized in that,

a detector capable of detecting the hydrogen fluoride gas or the Freon gas in the chamber is provided,

before the chamber is released, the concentration of the hydrogen fluoride gas or the freon gas is detected by the detector, and after the concentration of the hydrogen fluoride gas or the freon gas in the chamber becomes a predetermined reference value or less, a door of the chamber is opened.

10. The method of manufacturing a fine structure according to any one of claims 1 to 9, characterized in that,

in the IAD device, a film forming source formed by electron beams or resistance heating is arranged in the same chamber as the chamber,

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.

11. The method of manufacturing a fine structure according to any one of claims 1 to 10, characterized in that,

the fine structure has a multilayer film having 2 or more layers,

at least 1 layer of the multilayer film contains silicon dioxide.

12. The method of manufacturing a fine structure according to any one of claims 1 to 11, characterized in that,

in the etching, the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched, the accelerating voltage and the pressurizing current of the IAD apparatus, the etching gas introduction amount, the vacuum degree, or the argon gas introduction amount are adjusted so that the selection ratio of the metal mask to the layer to be etched (the etching rate of the layer to be etched/the etching rate of the metal mask) becomes 2 times or more.

13. The method of manufacturing a fine structure according to any one of claims 1 to 12, characterized in that,

in the etching, the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is set to 40cm or more.

14. The method of manufacturing a fine structure according to any one of claims 1 to 13, characterized in that,

the setting value of the IAD device during the etching is set to be within a range of 300-1200V of acceleration voltage and within a range of 300-1200 mA of acceleration current.

15. The method of manufacturing a fine structure according to any one of claims 1 to 14, characterized in that,

when the volume of the chamber is 2700L, the amount of introduction of the freon gas or the hydrogen fluoride gas into the chamber during the etching is 20sccm or more.

16. The method of manufacturing a fine structure according to any one of claims 1 to 15, characterized in that,

when the volume of the chamber was 2700L, the degree of vacuum during etching was set to 5.0X 10^－3～5.0×10^－ ¹Pa, in the range of Pa.

17. The method of manufacturing a fine structure according to any one of claims 1 to 16, characterized in that,

when the volume of the chamber is 2700L, the amount of argon gas introduced into the chamber during the etching is set to 20sccm or less.

18. The method of manufacturing a fine structure according to any one of claims 1 to 17, characterized in that,

in the gas exhaust mechanism of the chamber, the gas exhaust amount in the chamber is exhausted at 250L/min or less until the pressure in the chamber becomes 3.0X 10⁴Pa。

19. A manufacturing apparatus of a fine structure used in the manufacturing method of a fine structure according to any one of items 1 to 18,

a reactive gas is introduced into the plasma source within the chamber of the IAD device and etching is performed.

The above unit of the present invention can provide a method for producing a fine structure and an apparatus for producing a fine structure, which do not require a large-scale and multiple plasma sources, have an excellent etching rate, and can improve productivity.

The mechanism for finding the effect of the present invention or the mechanism for action is not clear, but is presumed as follows.

Since the reactive gas is introduced into the plasma source by using the IAD apparatus and etching is performed, the apparatus can be substantially increased in size and the processing area can be increased by installing the plasma source in a large-sized vacuum chamber such as a vapor deposition machine, thereby improving productivity. Further, since the film forming source is used in addition to the etching function, film formation and etching can be performed by the same apparatus, which also leads to improvement in productivity. Further, by using a reactive gas, the etching rate is also increased.

Drawings

Fig. 1 is a schematic diagram showing an example of an IAD device.

Fig. 2 (a) is a schematic view of a dome covered with a polytetrafluoroethylene sheet, (b) is a sectional view of (a), and (c) is a schematic view of a dome before being covered with a polytetrafluoroethylene sheet.

Fig. 3 is a cross-sectional view showing an example of the structure of the dielectric multilayer film.

Fig. 4 is a flowchart of a process of forming fine pores in the uppermost layer.

Fig. 5 is a conceptual diagram illustrating a step of forming a particle-shaped metal mask and forming a pore in the uppermost layer.

Detailed Description

The method for manufacturing a fine structure of the present invention is a method for manufacturing a fine structure by etching, and is characterized in that an IAD (ion assisted deposition) apparatus is used, and a reactive gas is introduced into a plasma source in a chamber of the IAD apparatus to perform etching.

This feature is a feature common to or corresponding to each of the embodiments described below.

In the embodiment of the present invention, it is preferable to introduce a gas containing a freon gas or a hydrogen fluoride gas as the reactive gas, in order to manufacture a desired fine structure by etching.

In view of making the harmful gas harmless or preventing the harmful gas from adhering to the inner wall of the chamber and the member disposed in the chamber, it is preferable that the IAD apparatus is provided with a means for making the harmful gas derived from the reactive gas harmless, and as the means for making the harmful gas harmless, the inner wall of the chamber and the member disposed in the chamber are covered with a material for making the harmful gas harmless or polytetrafluoroethylene over 10% or more of the surface area of the member.

In addition, as a means for performing the detoxification, a neutralization material for neutralizing the harmful gas is preferably provided in the chamber. Further, from the viewpoint of low cost and the possibility of making the gas harmless, it is preferable that the means for making the gas harmless is a neutralizing material for neutralizing the harmful gas by coating or vapor-depositing a film on the inner wall of the chamber and the members disposed in the chamber. In particular, from the viewpoint of enabling easy and reliable detoxification, it is preferable to form the neutralizing material by the vapor deposition before opening the chamber to the atmosphere.

In view of manufacturing a desired fine structure, it is preferable that the neutralizing material after film formation is peelable and that the method includes a step of peeling off the neutralizing material adhering to the fine structure.

In view of preventing harmful gas from being discharged to the outside of the chamber, it is preferable to provide a detector capable of detecting hydrogen fluoride gas or freon gas in the chamber, detect the concentration of the hydrogen fluoride gas or the freon gas by the detector before the chamber is released, and open the door of the chamber after the concentration of the hydrogen fluoride gas or the freon gas in the chamber becomes a predetermined reference value or less.

In view of the fact that a desired fine structure can be produced by forming a film after etching or etching after forming a film, it is preferable that the IAD apparatus includes a film formation source formed by an electron beam or resistance heating in the same chamber as the chamber, and the IAD apparatus includes a step of forming a film using the film formation source and a step of performing the etching using the plasma source.

From the viewpoint of improving the etching rate, it is preferable that the fine structure has a multilayer film having 2 or more layers, and at least 1 layer of the multilayer film contains silicon dioxide.

In view of the improvement of the etching rate, it is preferable that, at the time of the etching, the distance from the grid of the plasma source of the IAD device to the layer to be etched, the acceleration voltage and the pressurization current of the IAD device, the etching gas introduction amount, the vacuum degree, or the argon introduction amount are adjusted so that the selection ratio of the metal mask to the layer to be etched (etching rate of the layer to be etched/etching rate of the metal mask) becomes 2 times or more. In particular, in the 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 40cm or more.

The IAD device is preferably set to have a set value in the range of 300 to 1200V for acceleration voltage and 300 to 1200mA for acceleration current during etching, so that the amount of ions can be prevented from being excessively increased and the physical etching effect can be enhanced.

In view of the improvement of the etching rate, it is preferable that the introduction amount of the freon gas or the hydrogen fluoride gas in the chamber during the etching is 20sccm or more when the volume of the chamber is 2700L.

From the viewpoint of improvement in etching rate, it is preferable that the degree of vacuum during etching be 5.0 × 10 when the volume of the chamber is 2700L^－3～5.0×10^－1Pa, in the range of Pa.

In view of preventing the mask used for processing the fine structure from being physically etched by argon gas and disappearing, it is preferable that the amount of argon gas introduced into the chamber during the etching is 20sccm or less when the volume of the chamber is 2700L.

Preferably, in the gas exhaust mechanism for a chamber, the amount of gas exhausted from the chamber is 250L/min or less until the pressure in the chamber becomes 3.0X 10⁴Pa. The purpose of controlling the exhaust gas amount in this way is to discharge the gas from the gas discharge mechanism in an amount of about 1000L/min when the gas is present in the chamber, and to cope with this exhaust gas amount, the destruction machine is increased in size and the destruction capability corresponding to the exhaust gas amount is required. Therefore, by controlling the gas displacement in the direction of reducing the gas displacement to 250L/min or less, even an IAD apparatus having a large chamber can be in a state in which the chamber and the harmful machine are always connected, and can prevent harmful gas from being discharged into the atmosphere.

The apparatus for manufacturing a fine structure used in the method for manufacturing a fine structure of the present invention is characterized in that a reactive gas is introduced into a plasma source in a chamber of an IAD apparatus and etching is performed. This eliminates the need to increase the size of the plasma source and increase the number of plasma sources, and also has an excellent etching rate and improved productivity.

The present invention and its constituent elements, as well as the embodiments and modes for carrying out the present invention will be described below. In the present application, "to" is used to include numerical values described before and after the "to" as the lower limit value and the upper limit value.

[ outline of the method for producing a Fine Structure of the present invention ]

The method for manufacturing a fine structure of the present invention is a method for manufacturing a fine structure by etching, and is characterized in that an IAD (ion assisted deposition) apparatus is used, and a reactive gas is introduced into a plasma source of the IAD apparatus, and the etching is performed.

Preferably, the IAD apparatus may be a typical deposition apparatus using an IAD method, and a film formation source including an electron beam or resistance heating may be provided in the same chamber as that of the apparatus, and the film formation by deposition or the etching may be performed using the film formation source or the plasma source. The order of film formation and etching is not particularly limited.

The fine structure may have a single-layer film of 1 layer or a multilayer film of 2 or more layers, but in the present invention, a multilayer film is preferably included. Further, from the viewpoint of increasing the etching rate, it is preferable that at least 1 layer of the multilayer film contains silicon dioxide.

Further, the surface of the single-layer film or the multilayer film disposed in the IAD apparatus is etched by using the plasma source, thereby forming fine pores in the surface. In the case of a multilayer film, the etching forms pores that expose the surface portion of the layer adjacent to the uppermost layer. Specifically, the fine structure according to the present invention is preferably a dielectric multilayer film described later.

When etching is performed using the IAD apparatus, a reactive gas is introduced into a plasma source (IAD ion source described later).

In view of the fact that a desired fine structure can be produced by etching, it is preferable to introduce a gas containing a freon gas or a hydrogen fluoride gas as the reactive gas.

Further, since the reactive gas is introduced into the IAD apparatus and etched to generate a harmful gas derived from the reactive gas, it is preferable to provide a means (described later) for detoxifying the harmful gas to thereby detoxify the harmful gas.

The IAD device used in the method for manufacturing a fine structure of the present invention will be described in detail below, but the present invention is not limited thereto.

[ IAD device ]

Fig. 1 is a schematic diagram showing an example of an IAD device.

The IAD device 1 of the present invention includes a dome 3 in a chamber 2, and a substrate 4 arranged along the dome 3.

A deposition source (film formation source) 5 and an IAD ion source (plasma source) 7 are disposed at the bottom of the chamber 2. The gas supply portion 91 communicates with the chamber 2 via a port 91a, and the gas from the gas supply portion 91 is supplied to the IAD ion source 7. Further, the gas discharge portion 92 communicates with the chamber 2 via a port 92 a. The gas discharge portion 92, the port 92a, and the like constitute a gas discharge mechanism of the present invention.

< Evaporation Source >

The vapor deposition source 5 includes an electron gun or a resistance heating device that evaporates a vapor deposition material, and the vapor deposition material 6 is scattered from the vapor deposition source 5 toward the substrate 4, and is condensed and solidified on the substrate 4. At this time, the ion beam 8 is irradiated from the IAD ion source 7 toward the substrate 4, and a high kinetic energy of the ions is applied to form a dense film or to improve the adhesion force of the film during film formation.

The IAD ion source 7 ionizes the supplied reactive gas, discharges the ionized gas molecules (ion beams) into the chamber 2, and etches the exposed portions of the film formed on the substrate 4 where no mask is formed, by the discharged ion beams.

The substrate 4 used in the present invention includes resins such as glass, polycarbonate resin, cycloolefin resin, and the like, and is preferably a lens for vehicle mounting.

Although one vapor deposition source is shown in fig. 1 as the vapor deposition source 5, the number of vapor deposition sources 5 may be plural. A deposition substance 6 is generated from a film forming material (deposition material) of the deposition source 5 by an electron gun or resistance heating, and the film forming material is scattered and adhered to a substrate 4 (e.g., a lens) provided in the chamber 2, whereby a layer made of the film forming material (e.g., SiO as a low refractive index material described later) is formed on the substrate 4₂、MgF₂Or Al₂O₃Ta as a high refractive index material described later₂O₅、TiO₂Etc.).

In addition, although described later, in forming the dielectric multilayer film according to the present inventionContaining SiO₂In the case of the uppermost layer of (3), SiO is preferably used₂The target is disposed in the deposition source 5 and contains SiO as a main component₂Of (2) a layer of (a). Further, in order to further improve the hydrophilic function, it is preferable to add the hydrophilic function to the SiO₂The element having a smaller electronegativity than Si is mixed in the composition, and examples of the element having a smaller electronegativity than Si include sodium, magnesium, potassium, calcium, and lithium.

When sodium element is added, SiO containing sodium can be prepared₂And a target disposed in the evaporation source for direct evaporation. As another method, SiO may be independently disposed₂Target and sodium target, and evaporation of SiO by co-evaporation₂And sodium. In the present invention, from the viewpoint of improving the sodium content accuracy, it is preferable to prepare a sodium-containing SiO₂And a target disposed in the evaporation source for direct evaporation.

Na is preferably used as sodium₂O, MgO is preferably used as magnesium, and K is preferably used as potassium₂O, CaO in the case of calcium and Li in the case of lithium₂And O. Commercially available products can be used.

< IAD ion Source >

The IAD ion source 7 ionizes argon gas or oxygen gas supplied from the gas supply unit 91 and irradiates the substrate 4 with gas molecules (ion beam 8) ionized when forming a film on the substrate 4 (for example, including SiO)₂The uppermost layer of the film) is etched by ionizing the reactive gas supplied from the gas supply unit 91 and irradiating the film with the ionized ion beam 8.

The argon gas and the oxygen gas are also used as neutralizing agents for electrically neutralizing the positive charges accumulated on the substrate in order to prevent a phenomenon (so-called charging) in which positive ions emitted from the ion gun are accumulated on the substrate and the entire substrate is positively charged. As an effect of preventing charging and reducing damage to the metal block used for creating the structure, the condition of the neutralizer is preferably 1000mA or less. Preferably in the range of 250 to 500 mA.

As the IAD ion source 7, a koffman type (filament), a hollow cathode type, an RF type, a barrel type, a plasma accelerator type, or the like can be applied.

By irradiating the substrate 4 with the gas molecules from the IAD ion source 7, for example, molecules of the film forming material evaporated from a plurality of evaporation sources can be pressed against the substrate 4, and a film having high adhesion and high density can be formed on the substrate 4.

The IAD ion source 7 is provided at the bottom of the chamber 2 so as to face the substrate 4, but may be provided at a position offset from the facing axis.

In the etching, from the viewpoint of improvement in the etching rate, it is preferable to adjust the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched, the acceleration voltage and the pressurization current of the IAD apparatus, the etching gas introduction amount, the vacuum degree, or the argon gas introduction amount so that the selection ratio (etching rate of the layer to be etched/etching rate of the metal mask) between the metal mask described later and the layer to be etched (for example, the uppermost layer) becomes 2 times or more. In particular, it is preferable that the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 40cm or more during etching.

Preferably, the set value of the ion beam during etching is set to an acceleration voltage within a range of 300 to 1200V and an acceleration current within a range of 300 to 1200 mA. Within this range, it is possible to prevent the amount of ions from increasing excessively, the physical etching action from being enhanced, and a mask used for etching described later from being eliminated.

In the etching step, for example, if the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 40cm, the irradiation time of the ion beam may be 15 minutes, and if the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched is 100cm, the irradiation time of the ion beam may be 50 minutes.

In the film forming step, the ion beam irradiation time may be, for example, 1 to 800 seconds, and the ion beam particle irradiation number may be, for example, 1 × 10¹³～5×10¹⁷Per cm²。

The ion beam used in the etching step may be an ion beam of a freon gas or a hydrogen fluoride gas as a reactive gas, and when the volume of the chamber is 2700L, for example, the introduction amount of the freon gas or the hydrogen fluoride gas is preferably 20sccm or more. In addition, from the viewpoint of preventing the mask used for etching from being physically etched by argon gas and being lost, the amount of argon gas introduced during etching is preferably 20sccm or less.

The ion beam used in the film formation step may be an oxygen ion beam, an argon ion beam, or a mixed gas of oxygen and argon ion beam. For example, the amount of oxygen introduced is preferably in the range of 30 to 60sccm and the amount of argon introduced is preferably in the range of 0 to 10 sccm.

In the present invention, "sccm" is an abbreviation for standard cc/min and means 1 atmosphere (atmospheric pressure 10)¹³hPa), in cc units per 1 minute at 0 ℃.

< Dome >

The dome 3 holds at least one holder 3a, the holder 3a holding the substrate 4, the dome 3 also being referred to as an evaporation umbrella. The dome 3 has an arc-shaped cross section and a rotationally symmetric shape which passes through the center of a chord connecting both ends of the arc and rotates about an axis perpendicular to the chord as a rotationally symmetric axis. The substrate 4 held by the dome 3 via the holder 3a revolves around the shaft at a constant speed while the dome 3 rotates around the shaft at a constant speed, for example, at a constant speed.

The dome 3 can hold the plurality of holders 3a aligned in the rotation radial direction (revolution radial direction) and the rotation direction (revolution direction). This enables etching or film formation to be simultaneously performed on the plurality of substrates 4 held by the plurality of holders 3a, and the device manufacturing efficiency can be improved.

< gas supply part >

The gas supply unit 91 supplies 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.

The reactive gas includes, for example, carbon tetrafluoride (CF)₄) Sulfur hexafluoride (SF)₆) Trifluoromethane (CHF)₃) Among these, a freon gas or a hydrogen fluoride gas is particularly preferably contained.

Examples of the inert gas include argon (Ar) and nitrogen (N)₂) Helium (I)He), krypton (Kr), neon (Ne), and a mixed gas thereof.

< gas discharge part >

The gas exhaust unit 92 exhausts the chamber 2. The chamber 2 is evacuated to a predetermined degree of vacuum by the gas exhaust unit 92.

When the volume of the chamber 2 is 2700L, the degree of vacuum at the time of etching is preferably 5.0X 10^－3～5.0×10^－1Pa, in the range of Pa.

In the gas exhaust mechanism including the gas exhaust portion 92, the port 92a, and the like, it is preferable that the gas exhaust amount in the chamber 2 is 250L/min or less and the exhaust is performed until the pressure in the chamber 2 becomes 3.0 × 10⁴Pa. The purpose of controlling the exhaust gas amount in this manner is to make the amount of gas discharged from the gas discharge mechanism about 1000L/min when gas is present in the chamber 2, and to cope with this exhaust gas amount, the destruction machine is increased in size and the destruction capability according to the exhaust gas amount is required. Therefore, by controlling the gas displacement in the direction of reducing the gas displacement to 250L/min or less, even an IAD apparatus having a large chamber can be brought into a state in which the chamber and the harmful gas remover are always connected, and the harmful gas can be prevented from being discharged into the atmosphere.

Specifically, the gas exhaust amount can be reduced to 250L/min or less by reducing the pipe diameter connected to the gas exhaust portion 92 and the port 92 a. For example, a pipe having a diameter of 25mm, which is usually used, is a pipe having a diameter of 10mm or less, whereby control can be performed in a direction of reducing the amount of exhaust gas. As a method for making the diameter of the pipe smaller than 10mm, it is preferable to use an orifice plate having holes with a thickness of 1mm and smaller than 10 mm.

< units for rendering harmless >

As means for detoxifying harmful gases (for example, gases including freon gas and hydrogen fluoride gas) generated by etching, there may be mentioned a method in which the surface area of the inner wall of the chamber 2 and the surface area of the components disposed in the chamber 2 are covered with a material or polytetrafluoroethylene that renders the harmful gases harmless.

Examples of the members disposed in the chamber 2 include a dome 3, a vapor deposition source 5, and an IAD ion source 7.

Examples of the material for making the harmful gas harmless include calcium carbonate and calcium oxide.

In addition, in the case of covering with polytetrafluoroethylene, a polytetrafluoroethylene sheet (product name: PTFE sheet, model No. 638-17-97-01, manufactured by Tokyo Nitri apparatus Co., Ltd.) may be used.

By covering the inner wall of the chamber 2 with a material for detoxifying a harmful gas or polytetrafluoroethylene and disposing the member in the chamber 2, the harmful gas generated in the etching step can be detoxified or the harmful gas can be prevented from adhering to the inner wall of the chamber 2 or the member.

For example, when the surface (upper surface and lower surface) of the dome 3 is covered with polytetrafluoroethylene, it is preferable that the polytetrafluoroethylene sheet 3b be covered with a holder 3a (unused holder) remaining other than the holder 3a holding the substrate to be deposited or etched. Fig. 2 (a) is a schematic view of a dome covered with a polytetrafluoroethylene sheet, (b) is a sectional view of (a), and (c) is a schematic view of a dome before being covered with a polytetrafluoroethylene sheet. Fig. 1 shows an example in which the polytetrafluoroethylene sheet is not covered.

As means for performing the detoxification, a neutralizing material for neutralizing the harmful gas may be provided in the chamber 2. Specifically, calcium carbonate or calcium oxide is disposed at a position in the chamber 2 where there is no influence of vapor deposition or etching. Thereby, the harmful gas is neutralized and made harmless.

Further, as another means for making the harmful gas harmless, it is preferable that a neutralizing material for neutralizing the harmful gas is formed on the inner wall of the chamber 2 and the members disposed in the chamber 2 by coating or vapor deposition, in view of low cost and making the harmful gas harmless.

Examples of the neutralizing material used in the film formation by coating include calcium carbonate and calcium oxide, and examples of the neutralizing material used in the film formation by vapor deposition include calcium carbonate and calcium oxide.

In the case of forming the above-described neutralizing material by vapor deposition, it is preferable to form a film on the inner wall of the chamber and the members disposed in the chamber by vapor deposition before the chamber is released into the atmosphere, from the viewpoint of being effective for making the harmful gas after etching harmless.

In addition, from the viewpoint that the neutralizing material can be removed even if the neutralizing material adheres to the fine structure during film formation, and a desired fine structure can be produced, it is preferable to perform a step of peeling the neutralizing material adhering to the fine structure by peeling the neutralizing material formed by coating or vapor deposition. Examples of the peeling method include a peeling method using an etching solution, an organic solvent, and dry etching.

The means for performing the detoxification is preferably provided as a detoxifying machine 93 in the gas discharge unit 92. For the damage eliminating machine 93, for example, a dry etching exhaust gas treatment device (manufactured by yokoshihiki corporation) is preferably used.

In addition, a detector 11 capable of detecting a hydrogen fluoride gas or a freon gas is provided in the chamber 2. Since the hydrogen fluoride gas generated in the chamber 2 may exceed the safety standard, the detector 11 is provided to ensure safety of the working environment.

The detector 11 is preferably arranged such that a suction port of the gas faces downward. This improves the detection accuracy of the gas concentration. In the figure, the arrow of the broken line extending toward the detector indicates the direction of gas suction.

The detector 11 detects the concentration of the hydrogen fluoride gas or the freon gas in the chamber 2 before the door of the chamber 2 is opened, and after the concentration becomes a predetermined reference value or less, a control unit described later controls the door of the chamber 2 to be opened. Thereby, the discharge of the harmful gas to the outside of the chamber 2 can be prevented.

The detector 11 may be, for example, a theoretical analyzer GD-70D.

In addition, a detector capable of detecting other harmful gases may be provided in addition to the hydrogen fluoride gas and the freon gas.

The IAD apparatus 1 of the present invention includes a monitoring system 10. The monitoring system 10 is a system for monitoring the wavelength characteristics of a layer formed on the substrate 4 by monitoring the layer evaporated from each vapor deposition source 5 and adhering to the layer during vacuum film formation. By this monitoring system, it is possible to grasp the optical characteristics (for example, spectral transmittance, light reflectance, optical layer thickness, and the like) of the layer formed on the substrate 4.

The monitoring system 10 also includes a quartz layer thickness monitor, and can monitor the physical layer thickness of a layer formed on the substrate 4.

The monitoring system 10 also functions as a control unit that controls on/off switching of the plurality of evaporation sources 5, on/off switching of the IAD ion source 7, operations of the gas supply unit 91 and the gas discharge unit 92, opening and closing operations of a door (not shown) of the chamber 2, and the like, based on the layer monitoring result.

[ dielectric multilayer film ]

The fine structure produced by the method for producing a fine structure of the present invention preferably has a multilayer film of 2 or more layers, and preferably at least 1 layer contains silica. The multilayer film is preferably formed on a substrate.

Specifically, the fine structure of the present invention is preferably a dielectric multilayer film.

Preferably, the dielectric multilayer film has at least 1 low refractive index layer and at least 1 high refractive index layer, the uppermost layer farthest from the substrate is the low refractive index layer, the high refractive index layer disposed on the substrate side of the uppermost layer is a functional layer containing a metal oxide having a photocatalyst function, and the uppermost layer is a layer containing the silica, that is, a hydrophilic layer containing a metal oxide having a hydrophilic function, and has pores exposing a surface portion of the functional layer.

Here, the "low refractive index layer" means a layer having a refractive index of less than 1.7 on the d-line. The high refractive index layer is a layer having a refractive index of 1.7 or more on the d-line. The substrate is an optical component made of resin or glass, and is arbitrary in shape. The transmittance at a light wavelength of 550nm is preferably 90% or more.

The "photocatalyst function" as used herein means a function of a photocatalyst in the present inventionThe decomposition effect of organic substances. This is in the case of TiO having a photocatalyst property₂When ultraviolet light is irradiated, electrons are released, and active oxygen and hydroxyl radicals (OH radicals) are generated, and organic substances are decomposed by their strong oxidizing power. By adding TiO-containing additives to the multilayer film of the invention₂The functional layer of (2) can prevent organic substances and the like adhering to the optical member from contaminating the optical system as dirt.

Whether or not the photocatalyst effect is exhibited can be determined by, for example, accumulating the light quantity of 20J by UV irradiation to a sample colored with a pen in an environment of 80% at 20 ℃ and evaluating the color change of the pen in stages. The evaluation method of the pen was performed based on the information described in ISO-TC 206.

The "hydrophilic function" means that when the contact angle between a standard liquid (pure water) and the surface of the uppermost layer is measured according to the method defined in JIS R3257, a case where the water contact angle is 30 ° or less is referred to as "hydrophilic", and preferably 15 ° or less. In particular, the term "super-hydrophilic" as used herein means a case where the temperature is 15 ° or less.

Under specific measurement conditions, about 10. mu.L of pure water as the standard liquid was dropped onto a sample at a temperature of 23 ℃ and a humidity of 50% RH, and the measurement was carried out at 5 spots on the sample by using a G-1 apparatus manufactured by Elma Co., Ltd, and the average contact angle was obtained by averaging the measured values. The time until the contact angle measurement was measured within 1 minute after dropping the standard liquid.

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, but the present invention is not limited thereto. Further, other thin films may be formed between the functional layer and the uppermost layer and further layers above the uppermost layer within a range not to impair the effects of the present invention.

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 low refractive index layers 102 and 104 having a refractive index lower than that of the high refractive index layer. Further, the uppermost layer 106 farthest from the substrate 101 is a low refractive index layer, the high refractive index layer adjacent to the uppermost layer is a functional layer 105 mainly composed of a metal oxide having a photocatalyst function, and the uppermost layer has fine pores 30 exposing a surface portion of the functional layer and fine structures 31 other than the fine pores, thereby forming a multilayer film 107.

With this structure, the photocatalyst function (self-cleaning property) of the functional layer 105 can be exhibited on the surface of the multilayer film through the uppermost layer 106. Here, the fine structure 31 excluding the fine pores refers to a structural portion where the uppermost layer containing the metal oxide having the hydrophilic function is etched by the IAD apparatus 1 of the present invention using a metal mask described later to form the remaining fine pores.

The dielectric multilayer film preferably has a multilayer structure in which these high refractive index layers and low refractive index layers are alternately stacked.

The number of layers to be stacked is not particularly limited, but is preferably within 12 layers from the viewpoint of obtaining an antireflection layer while maintaining high productivity. That is, the number of layers depends on the required optical performance, but the reflectance of the entire visible region can be reduced by laminating about 3 to 8 layers, and the upper limit number is preferably 12 layers or less from the viewpoint of preventing film peeling or the like due to an increase in film stress.

From the viewpoint of improving the visibility of an image captured by a lens for vehicle mounting, the dielectric multilayer film of the present invention preferably has a light reflectance of 1% or less on average with respect to light incident from the normal direction in a region having a light wavelength of 450 to 780 nm. In the present invention, a multilayer film is formed on the substrate 101 to constitute an optical member. The light reflectance can be measured by a reflectance measuring instrument (USPM-ruii) (manufactured by olympus corporation).

As the material used for the high refractive index layer and the low refractive index layer of the present invention, for example, oxides of Ti, Ta, Nb, Zr, Ce, La, Al, Si, Hf, etc., or oxide compounds and MgF obtained by combining these oxides are preferable₂Are suitable. Further, by laminating a plurality of layers of different dielectric materials, it is possible to additionally reduce the reflectance of the entire visible regionThe function of (c).

The low refractive index layer is made of a material having a refractive index of less than 1.7, and in the present invention, it is preferable to contain SiO as a main component₂Of (2) a layer of (a). However, it is also preferable to contain other metal oxides, and SiO is also preferable from the viewpoint of light reflectance₂And part of Al₂O₃Mixture of (2), MgF₂And the like.

The high refractive index layer is made of a material having a refractive index of 1.7 or more, and for example, a mixture of an oxide of Ta and an oxide of Ti, and in addition, an oxide of Ti, an oxide of Ta, a mixture of an oxide of La and an oxide of Ti, or the like is preferable. The metal oxide used for the high refractive index layer preferably has a refractive index of 1.9 or more. In the present invention, Ta is preferred₂O₅、TiO₂More preferably Ta₂O₅。

The thickness of the entire dielectric multilayer film is not particularly limited, but is preferably 500nm or less, and more preferably in the range of 50 to 500nm, from the viewpoint of antireflection performance. When the thickness is 50nm or more, the optical characteristics for preventing reflection can be exhibited, and when the thickness is 500nm or less, the error sensitivity is lowered and the yield of the spectral characteristics of the lens can be improved.

The uppermost layer 106 preferably contains SiO as a main component₂The uppermost layer preferably contains an element having a smaller electronegativity than Si, and particularly preferably contains sodium element in an amount of 0.5 to 10 mass%. The more preferable range of the content is 1.0 to 5.0 mass%. By containing this element, super-hydrophilicity can be maintained for a long time.

Here, the "main component" means that 51 mass% or more of the entire mass of the uppermost layer is SiO₂Preferably 70% by mass or more, and particularly preferably 90% by mass or more.

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

(XPS composition analysis)

Device name: x-ray photoelectron spectroscopic analyzer (XPS)

The device type: quantera SXM

The device manufacturer: ULVAC-PHI

Measurement conditions: an X-ray source: monochromatic AlK alpha line 25W-15 kV

Degree of vacuum: 5.0X 10^－8Pa

Depth direction analysis was performed by argon ion etching. The data processing was performed using MultiPak manufactured by ULVAC-PHI.

Further, the film density of the uppermost layer is preferably 98% or more, and is preferably in the range of 98 to 100% from the viewpoint of salt water resistance and super hydrophilicity.

In particular, from the viewpoint of further improving the film density, it is preferable to form the uppermost layer by ion-assisted deposition using the IAD apparatus 1 of the present invention, and in this case, it is more preferable to apply heat of 300 ℃.

With this structure, since the uppermost layer of the multilayer film has a high film density, the multilayer film having excellent salt water resistance of the surface and capable of maintaining a low water contact angle for a long period of time in a high-temperature and high-humidity environment can be provided.

Method for measuring film density

Here, in the present invention, "film density" means space filling density, and is defined as a value p represented by the following formula (1). In addition, the film density was measured before etching.

Space filling density p ═ (volume of solid portion of film)/(total volume of film) … (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 minute hole portion of the membrane.

The film density can be measured by the following method.

(i) Only SiO was formed on a substrate made of white board glass BK7 (manufactured by SCHOTT corporation) (diameter: 30mm, thickness: 2mm)₂And a layer of sodium element (corresponding to the uppermost layer of the present invention), and the light reflectance of the uppermost layer was measured. On the other hand, (ii) the sum of the absolute values of theTheoretical value of light reflectance of a layer composed of the same material as the layer. Then, the film density of the uppermost layer is determined 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 instrument (USPM-ruii) (manufactured by olympus corporation).

In fig. 3, the preferred embodiment is one in which the functional layer 105 mainly composed of a metal oxide having a photocatalytic function is disposed in a layer adjacent to the uppermost layer 106, and the photocatalytic function can be effectively exerted, and the use of a metal oxide having a photocatalytic effect or a photoactive effect can remove surface organic matter that is a main component of contamination and contribute to maintaining the superhydrophilicity of the uppermost layer 106.

The metal oxide having a photocatalyst function is TiO₂It is preferable to have a high refractive index and reduce the light reflectance of the dielectric multilayer film.

The dielectric multilayer film of the present invention shown in fig. 3 is a multilayer film formed by laminating a low refractive index layer, a high refractive index layer, and an uppermost layer 106 on a substrate 101, but the uppermost layer may be formed on both sides of the substrate 101. That is, the uppermost layer is preferably exposed to the external environment, but may not be provided on the exposed side in order to prevent the influence of the internal environment, and for example, the uppermost layer may be formed on the inner side opposite to the exposed side. The dielectric multilayer film according to the present invention can be applied to optical members such as an antireflection member and a heat insulating member, in addition to a lens.

Further, the uppermost layer 106 preferably has pores having a specific shape by etching using the IAD apparatus 1 of the present invention described above.

[ method for producing dielectric multilayer film ]

The method for producing a dielectric multilayer film of the present invention preferably includes: forming at least 1 low refractive index layer and at least 1 high refractive index layer on a substrate; a step of forming a functional layer mainly containing a metal oxide having a photocatalyst function as the high refractive index layer; forming a hydrophilic layer containing a metal oxide having a hydrophilic function as an uppermost layer farthest from the substrate; and forming a pore in the uppermost layer to expose a surface portion 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 of a metal oxide or the like 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 deposition method, an ion beam deposition method, an ion plating method, and the like are known as a deposition system, and a sputtering method, an ion beam sputtering method, a magnetron sputtering method, and the like are known as a sputtering system.

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, a high-density film is preferably formed by using the IAD method.

Any of the layers of the multilayer film of the present invention is preferably formed by the IAD method, and more preferably the entire layer is formed by the IAD method. In the film formation by the IAD method, the scratch resistance of the entire fine structure can be further improved.

In the step of forming the pores in the uppermost layer, the pores are formed in the uppermost layer so as to expose a surface portion of the functional layer.

The method of forming the fine pores on the surface of the uppermost layer is as follows.

As shown in fig. 3, the uppermost layer 106 has a plurality of pores 30 for functioning as a photocatalyst in the adjacent functional layer 105 serving as a high refractive index layer.

The pores 30 are formed by etching using the IAD apparatus described above.

Hereinafter, a step of forming the fine pores in the uppermost layer will be described.

Fig. 4 is a flowchart of a step of forming pores in the uppermost layer, and fig. 5 is a conceptual diagram illustrating a step of forming a particle-shaped metal mask and forming 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). Here, in step S11, layers other than the uppermost layer 106 and the functional layer 105 in the multilayer film are formed. In other words, to a low refractive index layer adjacent to the lower side of the functional layer 105. The multilayer film is formed by various vapor deposition methods, IAD methods, sputtering methods, or the like. Further, depending on the structure of the dielectric multilayer film 100, the formation of the multilayer film in step S11 may also be omitted.

Next, as step 12, the functional layer 105 is formed, and as step 13, the uppermost layer 106 is formed. The film is preferably formed by an IAD method or a sputtering method, and more preferably by the IAD method.

After the uppermost layer forming process, the metal mask 50 is formed on the surface of the uppermost layer 106 (mask forming process: step S14).

As shown in fig. 5 (a), the metal mask 50 is formed in a particle shape on the surface of the uppermost layer 106. Thereby, the nano-sized metal mask 50 can be formed on the uppermost layer 106. As shown in fig. 5 (D), the metal mask 50 may be formed in a vein shape. 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 50 b. The 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 by a vapor deposition method so that the film thickness becomes 2nm, the metal mask 50 is likely to be in a particle form. Further, for example, when the metal mask 50 is formed by a vapor deposition method so that the film thickness becomes 12 to 15nm, the metal mask 50 is likely to have a vein shape. Further, when the film is formed by, for example, a sputtering method so that the film thickness becomes 10nm, the metal mask 50 is easily formed into a porous shape. By forming the metal to have a thickness in the above range, the metal mask 50 having an optimum particle shape, vein shape, or porous shape can be easily formed.

The metal mask 50 is made of Ag, Al, or the like, for example, and preferably Ag from the viewpoint of controlling the shape of the fine pores.

Next, a plurality of pores 30 are formed in the uppermost layer 106 (pore forming step: step S15). As shown in fig. 5 (B), during etching, a reactive gas is introduced into the IAD apparatus (IAD ion source) of the present invention.

The IAD apparatus of the present invention may be used for forming the multilayer film and the metal mask 50.

In the pore forming step, the material of the uppermost layer 106, specifically, SiO, is used₂The reactive gas of the reaction forms a plurality of pores. In this case, the SiO layer of the uppermost layer 106 can be removed without damaging the metal mask 50₂。

The reactive gas may be the above-mentioned freon gas or hydrogen fluoride gas.

Thereby, a plurality of pores 30 exposing the surface of the functional layer 105 are formed in the uppermost layer 106. In other words, the uppermost layer 106 corresponding to the exposed portion 50b of the metal mask 50 is etched to form the fine holes 30 and SiO as the uppermost layer forming material₂The fine structure 31 in (2) is in a state where the surface of the functional layer 105 is partially exposed.

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 using acetic acid or the like. In the IAD device of the present invention, Ar and O are used, for example₂The metal mask 50 is removed by dry etching using an etching gas.

When the metal mask 50 is etched using the IAD apparatus, a series of steps of forming a multilayer film, forming fine holes, and etching the metal mask 50 can be performed in the same IAD apparatus.

Through the above steps, the dielectric multilayer film 100 having the plurality of pores 30 in the uppermost layer 106 can be obtained.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following examples, the operation was carried out at room temperature (25 ℃ C.) unless otherwise specified. Unless otherwise specified, "%" and "part" mean "% by mass" and "part by mass", respectively.

EXAMPLE 1

[ production of dielectric multilayer film (Fine Structure) 1]

SiO was used as a glass substrate TAFD5G (refractive index 1.835, available from HOYA corporation)₂(Merck Co., Ltd.) for the low refractive index layer, OA600 (Canon photovoltaic Co., Ltd.) was used₂O₅、TiO、Ti₂O₅The mixture of (1) and (3) were laminated to a predetermined film thickness by the IAD method under the following conditions in accordance with the layer numbers 1 to 3 in table I. Then, as using TiO₂The functional layer (layer No. 4) and the uppermost layer (layer No. 5) of (a) were formed by vapor deposition so that the sodium content became 5 mass% by the IAD method, to obtain a dielectric multilayer film before formation of the pores having the number of layers 5 shown in table I.

< film Forming conditions >

(Chamber interior conditions)

The heating temperature is 370 DEG C

Initial vacuum of 1.33X 10^－3Pa

(Evaporation Source for film Forming Material)

Electron gun

< formation of Low refractive index layer, high refractive index layer, functional layer and uppermost layer >

Film-forming material for low refractive index layer: SiO 2₂(Canon photoelectric Co product name SiO₂)

The substrate is set in an IAD vacuum evaporation apparatus, and the film forming material is filled in a first evaporation source at a film forming rate

Low refractive index layers (layer 1 and layer 3) having thicknesses of 31.7nm and 34.6nm were formed on the substrate by/sec vapor deposition.

The IAD method uses an apparatus of the Optolan RF ion source "OIS One" at an acceleration voltage of 1200V, an acceleration current of 1000mA, and a neutralization current of 1500 mA. IAD introducing gas at O₂50sccm of Ar gas, 10sccm of Ar gas and 10sccm of neutral gas Ar.

High refractive indexFilm-forming material of layer: ta₂O₅(Canon photoelectric company product name OA-600)

Filling the second evaporation source with the film forming material at a film forming rate

And/sec deposition to form a high refractive index layer (layer 2) having a thickness of 30nm on the low refractive index layer. The formation of the high refractive index layer was also performed by the IAD method under heating at 370 ℃.

Film-forming material for functional layer: TiO 2₂(Fuji titanium Industrial Co., Ltd., product name T.O.P. (Ti)₃O₅))

The substrate is set in a vacuum evaporation apparatus, and the film-forming material is filled in a third evaporation source at a film-forming rate

And/sec deposition, thereby forming a functional layer (layer 4) having a thickness of 113nm on the low refractive index layer. The functional layer was formed by the IAD method under the heating condition of 370 ℃.

Preparation of uppermost layer film-forming Material: SiO 2₂And Na₂O (product name SiO manufactured by Fengdai of Kabushiki Kaisha)₂－Na₂O) particles mixed at a mass ratio of 95: 5.

The substrate is set in a vacuum evaporation apparatus, and the film forming material is filled in a fourth evaporation source at a film forming rate

And/sec deposition, thereby forming an uppermost layer (layer 5) having a thickness of 88nm on the functional layer. The functional layer was formed by the IAD method under heating at 370 ℃.

[ Table 1]

TABLE 1

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

(measurement of layer thickness)

The layer thickness is measured by the following method.

(1) TiO is put on the white board glass substrate in advance₂And SiO₂The film was formed to a film thickness of 1/4 λ (λ 550nm), and the spectral reflectance was measured.

(2) TiO formed in (1)₂And SiO₂Each layer was formed on the film under the above-described film formation conditions, and the spectral reflectance was measured, and the refractive index and the layer thickness of the layer were calculated from the amount of change.

Further, the composition analysis of the uppermost layer was measured using the following X-ray photoelectron spectroscopy apparatus (XPS).

(XPS composition analysis)

Device name: x-ray photoelectron spectroscopic analyzer (XPS)

The device type: quantera SXM

The device manufacturer: ULVAC-PHI

Measurement conditions: an X-ray source: monochromatic AlK alpha line 25W-15 kV

Degree of vacuum: 5.0X 10^－8Pa

The light reflectance was measured at a light wavelength of 587.56nm (d-line) using an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by Nippon spectral Co.

(measurement of refractive index under d line)

The refractive index shown in Table I was 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 and New technology. The refractive index of the layer obtained by adjusting the refractive index so as to match the actually measured light reflectance data was measured using thin film calculation software (Essential mechanical corporation).

< formation of fine pores in uppermost layer >

After the uppermost layer (layer 5) was formed, according to the pore forming method shown in fig. 3 and 4, Ag was used as a mask material, vapor deposition was used as a mask film formation method, the thickness of a metal mask (for example, Ag) was 39nm, and 0.5nm of Substance H4 (Ta manufactured by merck) was further formed on the metal mask₂O₅And La₂O₅The mixture of (1) and the mask had a vein-like shape, and fine holes were formed under the following etching conditions.

(etching conditions)

An IAD device: NIS-175 (manufactured by SYNCHRON Co., Ltd.)

Chamber size: 2700L

Etching gas: CHF₃

Etching gas introduction amount: 100sccm

Etching time: 10 minutes

Acceleration voltage of IAD device: 500V

Acceleration current of IAD device: 500mA

Vacuum degree of the chamber: 7.0X 10^－2Introduction of Pa gas

Ar gas introduction amount: 0sccm

Distance from grid of plasma source of IAD device to etched layer: 40cm (the selection ratio of the uppermost layer of the layer to be etched to the metal mask (etching rate of the layer to be etched/etching rate of the metal mask) is 2 or more times.)

< stripping of mask >

After the formation of the fine pores, the IAD apparatus was used to irradiate O₂The mask material Ag was stripped by plasma to produce the dielectric multilayer film 1. The peeling was performed under peeling condition 1 described below.

(stripping Condition 1 of mask)

An IAD device: NIS-175 (manufactured by SYNCHRON Co., Ltd.)

Chamber size: 2700L

Etching gas: o is₂，Ar

Etching gas introduction amount: 50sccm (O)₂)，10sccm(Ar)

Etching time: 10 minutes

Acceleration voltage of IAD device: 1000V

Acceleration current of IAD device: 1000mA

Vacuum degree of the chamber: 3.0X 10^－2Pa

Ar gas introduction amount: 10sccm

In addition, when the mask peeling was performed under the peeling condition 2 described below, Ag could be peeled off in the same manner as in the case of the peeling condition 1 described above, and the dielectric multilayer film 1 could be produced.

(stripping Condition 2 of mask)

The mask material Ag was peeled off by immersing in the following chemical for 1 minute.

Medicine preparation: type SEA-5 (manufactured by Linchun chemical Co., Ltd.)

[ production of dielectric multilayer film 2]

In the formation of the uppermost fine pores in the production of the dielectric multilayer film 1, the dielectric multilayer film 2 was produced in the same manner except that the distance from the grid of the plasma source of the IAD apparatus to the layer to be etched was set to 100cm as the etching condition.

[ production of dielectric multilayer film 3 ]

In the production of the dielectric multilayer film 1, the dielectric multilayer film 3 was produced in the same manner except that the inner wall of the chamber of the IAD device and 10% or more of the surface area of the member disposed in the chamber were covered with a polytetrafluoroethylene sheet (product name: PTFE sheet, model No. 638-17-97-01, manufactured by Tokyo Nitro Seisaku-Sho Co., Ltd.) as a detoxifying means for detoxifying a harmful gas.

[ production of dielectric multilayer film 4 ]

In the production of the dielectric multilayer film 3, the dielectric multilayer film 4 is produced in the same manner except that the above-mentioned detoxifying means is a covering of the polytetrafluoroethylene sheet, and a neutralizing material (product name: calcium carbonate, manufactured by Baishi calcium Co.) is placed in an upper part of the chamber where particularly HF gas is likely to accumulate.

[ production of dielectric multilayer film 5 ]

In the production of the dielectric multilayer film 4, the dielectric multilayer film 5 was produced in the same manner except that the inner wall of the chamber and the members disposed in the chamber were coated with a neutralizing material (product name: calcium carbonate, manufactured by Baishi calcium Co.) as the detoxifying means in addition to the covering of the polytetrafluoroethylene sheet and the provision of the neutralizing material.

After the etching, it was confirmed that the concentration of the HF gas in the chamber to be etched was 1.0ppm or less by using an HF gas concentration meter (GD-70D, manufactured by physical research and development instruments), and therefore, the door of the chamber was opened to take out the sample.

[ production of dielectric multilayer films 6 to 16 ]

In the production of the dielectric multilayer film 1, dielectric multilayer films 6 to 16 were produced in the same manner except that the etching conditions and the detoxifying means were changed as shown in table II below.

[ evaluation ]

< etch Rate >

The etching rate was calculated from the difference in film thickness between before and after etching in the etching step (formation of the uppermost fine pores) in the production of each dielectric multilayer film.

The difference in film thickness was calculated by film thickness simulation using a spectroscopic reflectance measuring machine.

Spectroscopic reflectance measuring machine: USPM-RUIII, PRODUCED BY OLINBASIS

(evaluation criteria)

Very good: more than 10nm/min

O: more than 3nm/min and less than 10nm/min

And (delta): more than 1nm/min and less than 3nm/min

X: less than 1nm/min

< Damage to mask >

The damage to the mask was evaluated from the remaining film thickness of the metal mask by etching when the uppermost fine holes were formed. The film thickness was evaluated as good when the film thickness was able to maintain the initial film thickness state of etching. The mask margin was calculated by simulating the film thickness based on the spectral reflectance meter.

O: the residual film thickness of the mask is 10nm or more

And (delta): the residual film thickness of the mask is more than 3nm and less than 10nm

X: the residual film thickness of the mask is less than 3nm

< fine pore processing state of fine structure >

The fine structure is evaluated based on the state of machining of the fine pores constituting the specific uneven shape of the uppermost layer. The machined state is obtained by classifying the uneven shape formed by machining the fine holes according to the following criteria.

(evaluation criteria)

O: the fine structure has pores with a root-mean-square height Sq of 10nm or more

And (delta): the fine structure has pores with a root-mean-square height Sq of 1nm or more and less than 10nm

X: the root mean square height Sq of the fine pores of the fine structure is less than 1nm

The root mean square height Sq of the fine structure was measured by the Atomic Force Microscope (AFM) described below.

The device comprises the following steps: dimension Icon manufactured by BRUKER corporation

A detector: silicon prober Model RTESPA-150 manufactured by BRUKER corporation

Measurement mode: peak Force Tapping

And (3) measuring the position: pore part of the uppermost layer

And (3) analysis: the root mean square height Sq (nm) of the photographed image was measured using software manufactured by BRUKER corporation

< concentration of HF gas in the chamber >

The pressure in the chamber after the mask was peeled off was 1.0X 10^－5After Pa, measurement of the concentration of HF gas using an HF gas detector described below was started, and the concentration value 2 minutes after the start of the measurement was measured.

The device comprises the following steps: GD-70D of Suiyan Gekko Swinhonism

[ Table 2]

TABLE II

As is clear from the above results, by using the method for producing a fine structure of the present invention, it is possible to reduce the increase in the etching rate and the damage to the mask as compared with the production method of the comparative example, and to produce a desired fine structure. In addition, it is found that when the detoxifying means is used (dielectric multilayer films 3 to 5), the concentration of HF gas in the chamber is significantly reduced and the effect on detoxification is achieved, as compared with the case where the detoxifying means is not used (dielectric multilayer film 1).

Description of the reference numerals

1 … IAD device; 2 … chamber; 3 … dome; 3a … stent; 3b … polytetrafluoroethylene sheet; 4 … a substrate; 5 … vapor deposition source (film formation source); 7 … IAD ion source (plasma source); 10 … monitoring system (control unit); 11 … a detector; 91 … gas supply section; 92 … gas exhaust; 93 … harmless machine; 30 … pores; 31 … fine structures other than pores; 50 … metal mask; 50a … metal portion; 50b … exposed portion; 100 … dielectric multilayer film (fine structure); 101 … a substrate; 102. 104 … low refractive index layer; 103 … high refractive index layer; 105 … functional layer; 106 … uppermost layer.

Claims

1. A method for manufacturing a fine structure by etching, characterized in that,

2. The method of manufacturing a fine structure according to claim 1,

the reactive gas is a gas containing a freon gas or a hydrogen fluoride gas.

3. The method of manufacturing a fine structure according to claim 1 or 2,

4. The method of manufacturing a fine structure according to claim 3,

5. The method of manufacturing a fine structure according to claim 3,

6. The method of manufacturing a fine structure according to claim 3,

7. The method of manufacturing a fine structure according to claim 6,

8. The method of manufacturing a fine structure according to claim 6 or 7,

the neutralizing material after film formation can be peeled off,

9. The method of manufacturing a fine structure according to any one of claims 1 to 8,

10. The method of manufacturing a fine structure according to any one of claims 1 to 9,

11. The method for producing a fine structure according to any one of claims 1 to 10,

the fine structure has a multilayer film having 2 or more layers,

at least 1 layer of the multilayer film contains silicon dioxide.

12. The method of manufacturing a fine structure according to any one of claims 1 to 11,

13. The method for producing a fine structure according to any one of claims 1 to 12,

14. The method of producing a fine structure according to any one of claims 1 to 13,

15. The method of producing a fine structure according to any one of claims 1 to 14,

16. The method of manufacturing a fine structure according to any one of claims 1 to 15,

when the volume of the chamber was 2700L, the degree of vacuum during etching was set to 5.0X 10^-3～5.0×10^-1Pa, in the range of Pa.

17. The method of manufacturing a fine structure according to any one of claims 1 to 16,

18. The method of manufacturing a fine structure according to any one of claims 1 to 17,

19. An apparatus for manufacturing a fine structure, which is used in the method for manufacturing a fine structure according to any one of claims 1 to 18,