JP2014185357A - Film formation method, method of producing thin film-provided workpiece and film formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film formation apparatus which is improved in utilization efficiency of a target and has productivity improved by increasing the film formation rate.SOLUTION: A film formation method is for forming a metal compound thin film on the to-be-treated surface 11a of a substrate 11 by applying a voltage to a target 10 and sputtering and includes an arrangement step and a thin film formation step. The target 10 has a plurality of sputtering surfaces 10a of such an irregular shape that the cross section is serration-like and leads to intersection of projections in the normal direction. In the arrangement step, the target 10 and the substrate 11 are arranged oppositely so that the substrate 11 is in place within a non-projection area, and the non-projection area is formed in such a manner that individual normal-direction projections of the sputtering surfaces 10a of the target 10 are formed in a state of being held between projection areas in the intersection area. In the thin film step, a thin film is formed on the to-be-treated surface 11a of the substrate 11 by applying a voltage to the target 10.

Description

  The present invention relates to a film forming method for forming a thin film by a sputtering method, a method for manufacturing an object to be processed with a thin film, and a film forming apparatus.

Conventionally, fluorides such as aluminum fluoride (AlF ₃ ) and calcium fluoride (MgF ₂ ) have been used as antireflection films (thin films) applied to optical elements (lenses and mirrors) in the visible light region. . In recent years, a sputtering method that is superior in terms of reproducibility, control of film unevenness, low-temperature film formation, etc., is attracting attention as a method for forming an antireflection film made of these fluorides. .

  However, in the sputtering method, the charged particles such as plasma are collided with the sputter material so that the film-forming particles are scattered in the form of atoms, so that the processing surface of the optical element is damaged by the charged particles during the film formation. There was a problem that it was difficult to control.

  In response to this, a reactive sputtering apparatus has been proposed in which a target is formed in a cylindrical shape, a sputtering gas is introduced from the bottom surface thereof, and a reactive gas is introduced from the vicinity of the optical element (see Patent Document 1). . Further, a sputtering apparatus has been proposed in which the sputtering surface of the target is inclined and the optical element is held outside the projection plane in the normal direction of the inclined sputtering surface (see Patent Document 2).

JP 2002-47565 A JP 2001-288565 A

  However, when the target is cylindrical as in Patent Document 1, the normal line of the target sputtering surface and the normal line of the optical element processing surface are orthogonal to each other, so that the sputtered film-forming particles reach the processing surface. There was a problem that the ratio became low. Moreover, when the optical element which is a to-be-processed object is hold | maintained outside a projection surface like patent document 2, although the ratio with which the sputtered film-forming particle | grain reaches | attains a processing surface becomes higher than patent document 1, a target and optical The distance to the element (T-S distance) increases. Therefore, there has been a problem that the film formation rate becomes slow.

  In view of the above, an object of the present invention is to provide a film forming apparatus that increases the utilization efficiency of a target and increases the productivity by increasing the film forming rate.

  The present invention relates to a film forming method in which a voltage is applied to a target and a metal compound thin film is formed on a processing surface of an object to be processed by sputtering. The target having a plurality of sputter surfaces formed on the non-projection region formed so as to be sandwiched by projection regions at regions where the projections in the normal direction of the plurality of sputter surfaces intersect each other. An arrangement step of opposingly arranging the target and the object to be processed so that a processing object is accommodated; a thin film forming step of applying a voltage to the target and forming a thin film on the processing surface of the object to be processed; It is provided with.

  In addition, the present invention provides a method for manufacturing a thin film-treated object in which a voltage is applied to a target and a metal compound thin film is formed on a processed surface of the object by sputtering, so that the cross sections of the normal direction intersect with each other. Is formed so that the target having a plurality of sputter surfaces formed in a concavo-convex shape in a sawtooth shape is sandwiched between projection regions in a region where the projections in the normal direction of the plurality of sputter surfaces intersect each other. An arrangement step of arranging the target and the object to be processed so that the object to be processed fits in the non-projection region, and applying a voltage to the target to form a thin film on the processing surface of the object to be processed. And a thin film forming step to be formed.

  Further, according to the present invention, in a film forming apparatus in which a voltage is applied to a target and a metal compound thin film is formed on a processing surface of an object to be processed by sputtering, the cross section has a sawtooth shape so that the projections in the normal direction intersect. Target holding means for holding the target having a plurality of sputter surfaces formed in a concavo-convex shape, a target opposite to the target, and projections in the normal direction of the plurality of sputter surfaces of the target intersecting each other And a target object holding means for holding the target object so as to fit in a non-projection area formed so as to be sandwiched between the projection areas.

  In addition, the present invention provides an uneven surface having a sawtooth cross section so that the projections in the normal direction intersect with each other in a thin film processed object in which a metal compound thin film is formed on a processing surface by sputtering by applying a voltage to a target. The target having a plurality of sputter surfaces formed in a shape, in a non-projection region formed so as to be sandwiched between projection regions in a region where the projections in the normal direction of the plurality of sputter surfaces intersect each other A thin film is formed on the processing surface by applying a voltage to the target after the processing surface is placed so as to be accommodated.

  In addition, the present invention provides a concave-convex shape in which the cross-section is sawtoothed so that the projections in the normal direction intersect in a thin film optical element in which a metal compound thin film is formed on the processing surface by sputtering by applying a voltage to the target The target having a plurality of sputter surfaces formed on the non-projection region formed so as to be sandwiched between projection regions at regions where the projections in the normal direction of the plurality of sputter surfaces intersect each other A thin film is formed on the processing surface by applying a voltage to the target after the surface is placed so as to fit.

  According to the present invention, the utilization efficiency of the target can be increased and the film formation rate can be increased to improve the productivity.

It is a schematic structure figure showing typically the whole structure of the sputtering device concerning the embodiment of the present invention. It is a figure which shows the target of the sputtering device which concerns on this embodiment. It is the schematic which shows the relationship between the emission angle of a sputtered particle, an incident angle, and TS distance. It is an arrangement plan of a target and a lens substrate concerning an example. It is the film thickness distribution figure in the processing surface which compared the film-forming rate in the arrangement | positioning shown in FIG.

  Hereinafter, a sputtering apparatus (film forming apparatus) 1 according to an embodiment of the present invention will be described with reference to FIGS. The control system of the sputtering apparatus 1 according to the present embodiment is connected to a computer (not shown) as a control unit, and can be collectively controlled by this computer. A program for carrying out the sputtering method is set in the control unit.

  First, a schematic configuration of the entire sputtering apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram schematically showing the overall structure of a sputtering apparatus 1 according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the target 10 of the sputtering apparatus 1 according to the present embodiment.

  As shown in FIG. 1, the sputtering apparatus 1 includes a film formation chamber 2 for forming a substrate (optical element) 11 as a target object by sputtering a target 10. An exhaust system 3 for exhausting the film forming chamber 2 is connected to bring the inside of the chamber 2 into a vacuum state. The exhaust system 3 is composed of a vacuum pump or the like.

  Inside the film forming chamber 2, a target unit (target holding unit) 4 that holds the target 10, a substrate holder (target object holding unit) 5 that holds the substrate 11, and a shield that shields the substrate 11 from the target 10. A plate 6 is disposed.

  The target unit 4 includes a cooling box 41 for cooling the target 10, a backing plate 42 connected to the cooling box 41, and an anode electrode 43. The cooling box 41 cools the target 10 by circulating cooling water supplied from outside. The cooling water supplied from the outside is adjusted to a desired temperature by a chiller (not shown), and the surface temperature of the target 10 can be kept constant by keeping the flow rate constant. The cooling box 41 includes a magnet 44 inside, and the magnet 44 is arranged so that a magnetic field in a direction parallel to the target 10 is formed. The backing plate 42 constitutes a cathode electrode and holds the target 10. The anode electrode 43 is disposed around the backing plate 42 via an insulating material 45 so as to surround the discharge space. A DC power supply 46 for applying DC power is connected between the backing plate (cathode electrode) 42 and the anode electrode 43.

  The substrate holder 5 includes a rotation mechanism (not shown) that can change the relative angle of the substrate holding surface with respect to the target holding surface of the backing plate 42, and a rotation mechanism (not shown) that can rotate about the rotation shaft 50. ing. The substrate holder 5 is connected to a moving mechanism 51, and the moving mechanism 51 is configured to be movable between the film forming chamber 2 and a load lock chamber 7 described later.

  Here, as shown in FIG. 2A, the target 10 has a sputter surface 10a formed in an uneven shape having a sawtooth cross section. Specifically, the target 10 includes a conical portion 10b provided in a substantially central portion, and a concentric circular portion 10d having a conical portion 10c and a concentric top portion 10c, and the sputter surface is formed by the conical portion 10b and the concentric circular portion 10d. The cross-sectional shape of 10a is serrated.

  Further, as shown in FIG. 2B, the conical portion 10b and the concentric circle portion 10d of the sputtering surface 10a are formed so that the projection in the normal direction does not cover the processing surface 11a of the substrate 11 that is disposed oppositely. In other words, the target 10 has a plurality of sputter surfaces formed in a concavo-convex shape with a sawtooth cross section so that the projections in the normal direction intersect, and the plurality of sputter surfaces project in the normal direction. It is formed so as not to be applied to the processing surface 11a of the substrate 11 disposed to face the substrate 11a. The target 10 is formed so as to be thinner in the thickness direction than the position of the top formed by connecting the side surfaces on both sides in the cross section of the plurality of sputtering surfaces along the inclination of the side surfaces. That is, the target 10 is formed so as to be leveled in the thickness direction.

  In addition, in this embodiment, although demonstrated using the target which has one concentric circle part, the target which has a some concentric circle part may be sufficient. In other words, any target having one or more concentric circles may be used.

  In this embodiment, a circular target is used so that a thin film can be formed efficiently and efficiently on a circular substrate. However, the shape of the target is changed according to the shape of the substrate. May be.

  The shielding plate 6 is provided between the target unit 4 and the substrate holder 5 and shields the target 10 and the substrate 11 so that the substrate 11 is not formed until the discharge is stabilized. The shielding plate 6 is configured to be opened and closed at high speed.

  A load lock chamber 7 is adjacent to the film forming chamber 2 via a gate valve 71, and an exhaust system 72 for connecting the load lock chamber 7 to a vacuum state is connected to the load lock chamber 7. ing. Since the substrate holder 5 is configured to be movable by the moving mechanism 51 between the film formation chamber 2 and the load lock chamber 7 which are in a vacuum state, the film formation chamber 2 is not exposed to the atmosphere. The board | substrate 11 can be carried in and carrying out to 2.

The film forming chamber 2 is connected to a first introduction port 8 for introducing a sputtering gas and a second introduction port 9 for introducing a reactive gas, and a gas supply system including a mass flow controller (not shown). This makes it possible to supply gas. From the first introduction port 8, an inert gas (for example, Ar, He, Ne, Kr, Xe) can be introduced as a sputtering gas. From the second introduction port 9, a fluorocarbon is used as a reactive gas. Gas and O ₂ can be introduced. Moreover, the gas introduced from here can restrict | limit flow volume, purity, a pressure, etc. with high precision by the mass flow controller not shown and a gas purifier.

  Next, a method for forming a substrate 11 using the sputtering apparatus 1 configured as described above (a method for manufacturing an optical element with a thin film (an object to be processed with a thin film)) will be described. First, the film forming chamber 2 is opened, and the target 10 is attached to the backing plate (cathode electrode) 42 in the film forming chamber 2 in advance (placement step (target fixing step)). The target 10 is selected according to the type of thin film to be formed. For example, when it is desired to form a low bending rate fluoride film, magnesium (Mg), aluminum (Al), or the like is preferably used. The target material may be a fluorine-added metal other than a metal as long as the electrical resistance is small. Further, the target 10 is used in which the sputter surface 10a is formed in an uneven shape having a sawtooth cross section so that the projection in the normal direction of the sputter surface 10a does not cover the processing surface 11a of the substrate 11 opposed to the target. It is done.

When the target 10 is attached, the film formation chamber 2 is closed and the film formation chamber 2 is evacuated by the exhaust system 3 so that the inside of the film formation chamber 2 is in a vacuum state of about 1 × 10 ⁻³ Pa. This is the preliminary preparation. When preparation is complete, the moving mechanism 51 is driven to place the substrate holder 5 in the load lock chamber 7, the load lock chamber 7 is opened with the gate valve 71 closed, and the substrate 11 is attached to the substrate holder 5. As the substrate 11, calcium fluoride crystal, quartz glass, silicon, glass, resin, or the like can be used. The rotation position of the substrate holder 5 is adjusted in advance using a rotation mechanism so that the film thickness distribution of the substrate 11 at a predetermined film formation position is constant. In the present embodiment, the substrate 11 is fixed so that the substrate 11 is accommodated in a non-projection region formed so as to be sandwiched by the projection region at a region where the projections in the normal direction of the plurality of sputtering surfaces of the target 10 intersect. The substrate 11 is arranged to face the target.

Next, the load lock chamber 7 is closed, and the inside of the load lock chamber 7 is exhausted by the exhaust system 72 so that the inside of the load lock chamber 7 is in a vacuum state of about 1 × 10 ⁻³ Pa. When the evacuation is completed, the gate valve 71 is opened, the moving mechanism 51 is driven, and the substrate 11 held by the substrate holder 5 is moved to a predetermined film formation position in the film formation chamber 2 (fixing process (processed) Body placement step)). Here, the predetermined film forming position is a position adjusted so that the projection in the normal direction of the sputtering surface 10 a of the target 10 does not reach the processing surface 11 a of the substrate 11.

Here, when reactive sputtering is performed with a normal parallel plate magnetron sputtering apparatus, a thin compound film such as aluminum fluoride (AlF ₃ ) or magnesium fluoride (MgF ₂ ) is formed on the surface of the target due to the influence of the reaction gas. Is done. When the sputtering surface on which this compound film is formed is sputtered, some negative ions are formed, and the formed negative ions are accelerated by an ion sheath voltage to become negative ions having large kinetic energy and directionality. Since these negative ions are accelerated in a direction substantially perpendicular to the target surface, if the substrate is placed in the projection plane in the normal direction of the sputtering surface, negative ions having large kinetic energy collide with the substrate, It will cause great damage to the board.

  The target 10 according to the present embodiment is formed in an uneven shape in which the sputter surface 10a is serrated. Then, when the substrate 11 is disposed so as to overlap the part of the projection surface of the target 10, the sawtooth-shaped sputtering surface 10 a is outside the projection surface in the normal direction of the sputtering surface 10 a of the target 10. It is formed to become. Thereby, even if negative ions are formed in the vicinity of the sputtering surface 10a of the target 10, the distance (TS distance) between the target 10 and the substrate 11 can be reduced while suppressing damage to the substrate 11. it can.

  Next, an inert gas (Ar gas) is introduced into the film forming chamber 2 from the first introduction port 8 with the shielding plate 6 closed so that no film is formed on the substrate 11. When a predetermined DC voltage is applied to the backing plate 42 by the DC power source 46, glow discharge occurs and the inert gas (Ar gas) is ionized. A DC power supply is suitable for the power supply.

  When a high frequency power supply is used, a large self-bias voltage is generated on the substrate 11. When this self-bias voltage is generated, cations are accelerated by the self-bias voltage and enter the substrate 11 to damage the substrate 11. This plasma is stable even when the pressure in the film forming chamber 2 is about a few Pa. Plasma is generated even at such a low pressure because of the magnetron effect of the magnet 44 housed in the cooling box 41, the electrons perform cyclotron motion in a plane perpendicular to the magnetic field, and the electron density in the vicinity of the target 10 is reduced. Because it can be raised. In addition, the magnetron of the magnet 44 increases the electron density in the vicinity of the target 10 and decreases the electron temperature and electron density in the vicinity of the substrate 11, thereby suppressing the incidence of charged particles on the substrate 11 and causing damage to the substrate 11. There is also an effect that it can be reduced.

  Next, a reactive gas (fluorine gas) is introduced into the film forming chamber 2 from the second introduction port 9. When the reactive gas is introduced, the sputtering surface 10a of the target 10 is fluorinated and easily covered with an insulator. If it does so, an insulator will be charged up, and it will become easy to generate abnormal discharge because this will carry out dielectric breakdown by ion and an electron. When abnormal discharge occurs, foreign matter enters the film, resulting in a film with a rough surface. As a countermeasure, if an alternating current of about 500 KHz is superimposed on a DC voltage, the charge can be canceled and abnormal discharge can be prevented. However, as described above, if the frequency to be superimposed is increased too much, a self-bias voltage is generated on the substrate 11, and cations are incident on the substrate 11 and damage the substrate 11. Still, if the frequency is 350 KHz or less, the influence of damage is not great. That is, abnormal discharge can be prevented if it is 500 KHz or less, but 350 KHz or less is preferable in view of the influence of damage.

  The film formation pressure when the sputtering gas and the reactive gas are introduced is adjusted by adjusting the valves of the exhaust system 3 and the mass flow controllers provided in the first introduction port 8 and the second introduction port 9 to form the film formation chamber 2. The inside is maintained at 0.1 to 3.0 Pa. If the pressure is raised too much, the film becomes rough and has a low density, and if the pressure is lowered too much, discharge tends to occur. When the discharge voltage is stabilized, the shielding plate 6 is opened and film formation is started (thin film formation step).

  Here, FIG. 3 shows the relationship between the emission angle of sputtered particles, the incident angle, and the TS distance. The emission angle of the sputtered particles emitted from the sputtering surface 10a of the target 10 by sputtering is α, the angle at which the sputtered particles are incident on the substrate 11 is β, the TS distance is r, and n is a positive real number. When scattering and reaction during the transport of sputtered particles are ignored, there is generally a relationship that the film formation rate is proportional to “(cos α) n · cos β / r 2”. In order to increase the film formation rate, it is necessary to make the emission angle α and the incident angle β smaller and the TS distance smaller. In addition, in order to obtain a high quality film from the viewpoint of film quality such as refractive index and film absorption, it is necessary to form the film with an optimal T-S distance.

  Therefore, as shown in FIG. 2, when the substrate 11 and the target 10 are arranged to face each other, the cross section of the sputter surface 10a is formed in a serrated uneven shape so that the substrate 11 is not exposed to the projection in the normal direction of the sputter surface 10a. Form. Then, the TS distance can be freely brought close to the optimum position without increasing the emission angle α and the incident angle β. Therefore, even if negative ions are formed in the vicinity of the sputtering surface 10a of the target 10, the sputtered sputtered particles are efficiently guided to the processing surface 11a of the substrate 11 while suppressing damage to the substrate 11, and a high film formation rate is achieved. Can be formed.

  Such a film is a single body or a stacked body on the substrate 11 and can function as an antireflection film, an increased reflection film, a filter, or the like of an optical component.

Next, an example in which a thin film (metal compound thin film) of magnesium fluoride (MgF ₂ ), which is a low absorption and low refractive index material, is formed on a lens substrate (optical element) using the sputtering apparatus 1 shown in FIG. This will be described with reference to FIGS. FIG. 4 is a layout diagram of the target and the lens substrate according to the embodiment. FIG. 5 is a film thickness distribution diagram in the processing surface in which the film formation rates in the arrangement shown in FIG. 4 are compared. 4A is a target layout according to the present invention, FIG. 4B is a general plan target layout, and FIG. 4C is a target layout according to a conventional example. .

  As shown in FIG. 4, in any of the cases (a), (b), and (c), the TS distance at the position where the lens substrate and the target are closest to each other is made the same (50 mm), and sputtering is performed. The lens substrate is arranged so as not to be projected in the normal direction of the surface. The film formation rates were compared when the film formation conditions other than the arrangement of the target and the lens substrate were the same, and the film formation was performed with the arrangements (a), (b), and (c).

A target made of metal Mg having an outer diameter of 3 inches was used as the target, and a lens substrate made of BK7 glass having an outer diameter of 30 mm was used. The outer diameter ratio between the lens substrate and the target (the ratio of the length in the direction intersecting the thickness direction) is preferably lens substrate: target = 1: 5 or less, and more preferably lens substrate: target = 1: 3 or less. preferable. As the reactive gas, a gas obtained by diluting F ₂ gas with Ar gas and adjusting the concentration of F ₂ gas to 10% was used.

First, the cleaned lens substrate is placed on the substrate holder moved to the load lock chamber, and the load lock chamber is exhausted until the load lock chamber is in a vacuum state of 1 × 10 ⁻³ Pa or less with the gate valve closed. To do. When the evacuation is completed, the gate valve is opened and the moving mechanism is driven to transport the lens substrate to the film formation position in the film formation chamber.

Next, the shielding plate was closed, 100 SCCM of Ar gas was introduced from the first introduction port, and 200 SCCM of gas having a F ₂ gas concentration adjusted to 10% was introduced as the reactive gas from the second introduction port. The pressure in the film forming chamber at this time was set to 0.31 Pa.

  Next, a DC voltage of 200 W was applied as sputtering power to the backing plate (cathode electrode) to generate magnetron plasma on the sputtering surface of the target. At the same time, a rectangular voltage that reverses the polarity of the target surface was superimposed at 5 KHz to cancel the charge in the vicinity of the sputtering surface of the target so that stable discharge was possible. The self-bias, which increases during high-frequency discharge, is reduced by using almost direct current discharge, which reduces the possibility that cations are accelerated by the self-bias voltage and enter the lens substrate, causing damage to the lens substrate. ing. In addition, by canceling the charge, abnormal discharge can be suppressed and a metal compound thin film free from dust and foreign matters can be formed.

  The discharge was continued for a while, and when the time was stable, the shielding plate was opened and film formation was started. Films (a), (b) and (c) were formed at the same film formation time.

  FIG. 5 shows in-plane film thickness distribution charts comparing the film formation rates in (a), (b) and (c). As shown in FIG. 5, when the total film thickness obtained by adding up all the film thicknesses in the processing surface is compared, it can be seen that (a) is 1.7 times as thick as (b). . Similarly, it can be seen that (a) is 1.3 times as thick as (c). As described above, in (a) having the same configuration as that of the present embodiment, the distance between the target and the substrate (TS distance) can be reduced, and the film can be formed efficiently and at a high film formation rate. .

In (a), since the incidence of charged particles in plasma on the lens substrate is suppressed, a transparent MgF ₂ film can be formed in the visible light region when the temperature of the lens substrate is 80 ° C. or lower. The formed MgF ₂ film had good adhesion, and the hardness of the film was as high as the hand-coating (300 ° C. heating) for vapor deposition. The packing was close to 100%, and almost no change in spectral characteristics was observed. Therefore, it is also possible to use plastic or the like as the lens substrate.

  In addition, since the sputtering rate is stable, it is possible to easily control the film with higher accuracy than the conventional vapor deposition method, and it is possible to form a high-quality optical thin film. Therefore, an optical component having characteristics as designed can be manufactured by using an antireflection film or a mirror formed by laminating such optical thin films.

  In addition, even when the substrate size is increased, the target size corresponding to the substrate size is set, and the sputter surface is made uneven according to the substrate size. As a result, the film can be formed with the TS distance from the target close to the optimum position. Therefore, even when negative ions are formed near the target surface, sputtered particles can be efficiently guided to the lens substrate while suppressing damage to the lens substrate. As a result, the film can be formed at a high film formation rate.

  Further, by performing the step of preparing an optical element and the film forming step of forming a film on the optical element by the above-described film forming method, the productivity can be improved and an excellent optical element can be manufactured.

1 Sputtering equipment (film deposition equipment)
4 Target unit (target holding means)
5 Substrate holder (processed object holding means)
DESCRIPTION OF SYMBOLS 10 Target 10a Sputtering surface 10b Conical part 10c Top part 10d Concentric circle part 11 Substrate (object to be processed, optical element)
11a Treatment surface 46 DC power supply

Claims (13)

In a film forming method in which a voltage is applied to a target and a metal compound thin film is formed on a processing surface of an object to be processed by sputtering.
The target having a plurality of sputter surfaces formed in a concavo-convex shape having a sawtooth cross section so that the projections in the normal direction intersect with each other, the projections in the normal direction of each of the plurality of sputter surfaces intersecting each other An arrangement step of disposing the target and the object to be processed so that the object to be processed fits in a non-projection area formed so as to be sandwiched between the projection areas in the area;
A thin film forming step of applying a voltage to the target to form a thin film on the processing surface of the object to be processed.
A film forming method characterized by the above. The target is formed to be thinner in the thickness direction than the position of the top formed by tying side surfaces on both sides in the cross section of the plurality of sputtering surfaces along the inclination of the side surfaces.
The film forming method according to claim 1. The arrangement step includes
A target fixing step of fixing the target;
A target object arrangement step of arranging the target object with respect to the fixed target so that the target object fits in the non-projection region,
The film forming method according to claim 1, wherein: The concavo-convex shape of the plurality of sputter surfaces is composed of a conical portion and one or more concentric circular portions having a top portion concentric with the conical portion.
The film forming method according to claim 1, wherein the film forming method is characterized in that: The metal compound thin film is a fluoride film;
The film forming method according to claim 1, wherein the film forming method is characterized in that: Sputtering by superimposing a voltage having a frequency of 350 KHz or less on the DC voltage applied to the target,
The film forming method according to claim 1, wherein the film forming method is characterized in that: The length ratio of the object to be processed and the target in the direction intersecting the thickness direction is 1: 5 or less.
The film forming method according to claim 1, wherein: The object to be processed is an optical element.
The film forming method according to claim 1, wherein: In the method of manufacturing a target object with a thin film in which a voltage is applied to the target and a metal compound thin film is formed on the processing surface of the target object by sputtering.
The target having a plurality of sputter surfaces formed in a concavo-convex shape having a sawtooth cross section so that the projections in the normal direction intersect with each other, the projections in the normal direction of each of the plurality of sputter surfaces intersecting each other An arrangement step of disposing the target and the object to be processed so that the object to be processed fits in a non-projection area formed so as to be sandwiched between the projection areas in the area;
A thin film forming step of applying a voltage to the target to form a thin film on the processing surface of the object to be processed.
A manufacturing method of a to-be-processed object with a thin film characterized by things. Preparing the optical element;
A film forming step of forming a film by the film forming method according to claim 8 with respect to the optical element.
A method for producing an optical element with a thin film. In a film forming apparatus that applies a voltage to a target and forms a metal compound thin film on the processing surface of the object to be processed by sputtering.
Target holding means for holding the target having a plurality of sputter surfaces formed in a concavo-convex shape with a sawtooth cross section so that the projections in the normal direction intersect,
The object to be covered is placed in a non-projection area formed so as to face the target and be sandwiched by the projection area at the area where the projections in the normal direction of the plurality of sputtering surfaces of the target intersect each other. A processing object holding means for holding the processing object,
A film forming apparatus. In a target object with a thin film in which a metal compound thin film is formed on the processing surface by sputtering by applying a voltage to the target,
The target having a plurality of sputter surfaces formed in a concavo-convex shape having a sawtooth cross section so that the projections in the normal direction intersect with each other, the projections in the normal direction of each of the plurality of sputter surfaces intersecting each other A thin film is formed on the processing surface by applying a voltage to the target after placing the processing surface in a non-projection region formed so as to be sandwiched between projection regions in the region.
An object to be treated with a thin film. In the optical element with a thin film in which a voltage is applied to the target and a metal compound thin film is formed on the processing surface by sputtering,
The target having a plurality of sputter surfaces formed in a concavo-convex shape having a sawtooth cross section so that the projections in the normal direction intersect with each other, the projections in the normal direction of each of the plurality of sputter surfaces intersecting each other A thin film is formed on the processing surface by applying a voltage to the target after placing the processing surface in a non-projection region formed so as to be sandwiched between projection regions in the region.
An optical element with a thin film.

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