JP2011102436A - Thin film deposition method and thin film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film deposition method for an optical article in which the bending of a substrate after the deposition of thin films is reduced, and to provide a thin film deposition method. <P>SOLUTION: The thin film deposition system includes: a substrate holder 13 holding a substrate S; and a film deposition process region 30 and a reaction process region 70 formed on the sides respectively opposite to a film deposition process region 20 and a reaction process region 60 with the substrate holder therebetween, and deposits thin films simultaneously on the faces of the opposite sides in the substrate. The film thickness of the thin films is decided based on the kind and film thickness of the thin film deposited on either side of the substrate, and the thin films are deposited on both the sides of the substrate while offsetting the curving of the substrate caused by the internal stress of the thin films. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a thin film forming method and a thin film forming apparatus, and more particularly to a thin film forming method and a thin film forming apparatus capable of providing an optical article with less bending of a substrate after the thin film is formed.

  An optical thin film is formed on the substrate surface by physical vapor deposition such as sputtering to produce optical products such as interference filters such as anti-reflection filters, half mirrors, various bandpass filters, dichroic filters, and coloring on the surface of various decorative products. It is common practice to produce a decorative article having specific optical properties by coating.

Such an optical product is formed by a substance flying from a target adhering to the surface of a substrate such as glass in a vacuum vessel.
By the way, when a thin film is formed on the substrate surface by aggregation from the gas phase, internal stress is generated in the thin film. The internal stress refers to the force exerted by the object parts on both sides of each other through an arbitrary unit area considered inside the object. Usually, internal stress includes thermal stress and true stress. The thermal stress is a stress generated by a difference in coefficient of thermal expansion between the thin film and the substrate or between the thin film and the thin film. On the other hand, the true stress is a stress generated by a difference between an atomic arrangement in the vicinity of the thin film surface or the interface with the substrate and an atomic arrangement in the thin film. The internal stress is roughly classified into a compressive stress that tends to shrink toward the center of the thin film and an extension stress that tends to stretch toward the outer direction of the thin film depending on the type.

  For example, silicon oxide (SiO 2) has a compressive stress, and a thin film made of silicon oxide exerts a force that tends to shrink toward the center of the film. For this reason, the phenomenon that the substrate is curved to the thin film side is known in the case of a substrate coated with a silicon oxide film on one side. In particular, since thin films are formed using a thin substrate having a thickness of 0.5 mm or less in recent years, the curvature of the substrate due to internal stress is particularly large, greatly affecting the optical characteristics of products such as filters.

  In order to prevent the bending due to the internal stress of the thin film, it has been conventionally performed to correct the bending of the substrate by forming a thin film having an internal stress that balances the internal stress of the thin film on the back surface of the substrate on which the thin film is formed. It was. For example, in Patent Document 1, a highly reflective mirror layer is formed on one surface of a substrate, and then an MgF2 reflective layer having an internal stress commensurate with the tensile stress of the highly reflective mirror layer is deposited on the back surface of the substrate, thereby bending the substrate. A corrected optical member is disclosed.

Japanese Examined Patent Publication No. 62-018881 (page 3, FIG. 3)

Such an optical member is usually produced by first forming a thin film on one surface and then inverting it to form a thin film on the back surface. In a conventional thin film forming apparatus, after forming a thin film on one side, the substrate holder holding the substrate is unloaded from the vacuum vessel, the substrate is inverted and set again, and then the substrate holder is loaded again into the vacuum vessel. A thin film was formed on the back surface of the substrate.
There is also known a technique in which a reversing mechanism for reversing the substrate is provided in the vacuum vessel, and after performing a thin film forming process on one side of the substrate, the substrate is reversed and a thin film forming process is performed on the back side.

When the substrate holder is carried out of the vacuum vessel as described above, the vacuum state in the vacuum vessel is once released, the substrate holder is taken out, and then the inside of the vacuum vessel is again evacuated to a vacuum state. Therefore, it takes time to carry in / out the substrate holder and exhaust the vacuum vessel, and there is a disadvantage that it takes time for the manufacturing process. In addition, since the deposited substrate is exposed to the atmosphere, the substrate surface may be contaminated.
In addition, in a thin film forming apparatus equipped with a reversing mechanism, it is possible to omit the trouble of carrying the substrate holder out of the vacuum vessel or evacuating the vacuum vessel again. A complicated reversing mechanism for reversing the substrate is required, and dirt attached to the reversing mechanism may be peeled off when the substrate is reversed to contaminate the thin film surface.

Furthermore, in the above technique, since a thin film is formed on one side of the substrate and then another thin film is formed on the back surface, when the thin film is formed on one side of the substrate, the substrate is already subjected to the internal stress of the formed thin film. Is curved. Even if this substrate is inverted and a thin film is formed on the back surface of the substrate to correct the curvature, it is not easy to return the curved substrate to a flat substrate, and the curved substrate is reverse to the bending direction. Since it is curved again by applying stress, there is a disadvantage that the thin film formed on the substrate surface is easily peeled off.
Further, since the thin film is formed on the curved surface, there is a disadvantage that the film thickness distribution is uneven on the substrate surface. For example, when a thin film is formed on a concavely curved substrate, the film thickness becomes larger at the outer peripheral portion than at the central portion of the substrate, and there is a disadvantage that a uniform film thickness cannot be obtained.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thin film forming method and a thin film forming apparatus capable of providing an optical product with less bending of a substrate after forming the thin film. There is.

  According to the thin film forming method of the first aspect, the object is to form an intermediate thin film on the substrate by sputtering the target disposed in the film forming process region in the vacuum container, A thin film forming method using a sputtering apparatus for forming a thin film by reacting the intermediate thin film with a reactive gas in a reaction process region, wherein the intermediate thin film is formed substantially simultaneously by sputtering on both sides of the substrate. An intermediate thin film forming step, a reaction step of reacting a reactive gas with each of the intermediate thin films formed on both surfaces of the substrate to form a thin film substantially simultaneously, and one surface of the substrate on the opposite side of the substrate Forming a thin film that counteracts the curvature of the substrate by the thin film formed on the surface, and the thickness of the thin film formed on the opposite surface of the substrate is formed on one surface of the substrate Thin Type and it is determined based on the film thickness, it is solved by.

Thus, according to the thin film forming method of the first aspect, the thin film that cancels the curvature due to the stress of the thin film formed on the opposite surface is formed almost simultaneously on one surface of the substrate. The thickness of the thin film formed on the side surface is determined based on the type and thickness of the thin film formed on one surface of the base. As described above, since the stress of the thin film is determined by the type and film thickness of the thin film to be formed, when the type and film thickness of the thin film formed on one surface of the base are set, the base is determined based on this. The film thickness of the thin film formed on the opposite surface is also determined. Therefore, by adjusting the film thickness of the thin film formed on one side of the substrate, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film. In addition, as in the conventional thin film formation method, it eliminates the trouble and inconvenience of forming a thin film on one surface of the substrate and then inverting the substrate to form a thin film on the opposite surface. It is possible to provide an optical product having excellent optical characteristics with less curvature of the substrate.
Furthermore, according to the thin film forming method of the first aspect, the thin film is formed on the one surface of the substrate while the thin film is formed on the opposite surface at the same time. For this reason, since the thin films are stacked while canceling the curvature of the base due to the stress of the thin film formed on the surface of the base, it is possible to form the thin film while keeping the base substantially flat. Accordingly, the present invention provides an optical product having superior optical characteristics in which the substrate is less bent by the stress of the thin film than the conventional thin film forming method in which the curved substrate is inverted by forming the thin film and the thin film is formed on the back surface. It becomes possible.

  According to the thin film forming method of claim 2, the object is to form an intermediate thin film on a substrate by performing sputtering on a target disposed in a film forming process region in the vacuum container, A thin film formation method using a sputtering apparatus for forming a thin film by reacting the intermediate thin film with a reactive gas in a reaction process region, wherein the first intermediate thin film is formed on both surfaces of the substrate by sputtering. A first intermediate thin film forming step performed substantially simultaneously and a second intermediate thin film forming substantially simultaneously the second intermediate thin film having a refractive index different from the refractive index of the first intermediate thin film by sputtering on both surfaces of the substrate. A thin film forming step, a reaction step in which a reactive gas is reacted with each of the first intermediate thin film and the second intermediate thin film formed on both surfaces of the substrate to form a thin film substantially simultaneously, and the base A thin film formed on the opposite surface of the substrate, and a thin film formed on the opposite surface of the substrate is formed on the opposite surface of the substrate. The thickness is solved by being determined based on the type and thickness of the thin film formed on one surface of the substrate.

Thus, according to the thin film forming method of claim 2, two kinds of intermediate thin films having different refractive indexes are formed almost simultaneously on both surfaces of the substrate in the film forming process region, and the intermediate thin film and the reactive gas are formed in the reaction process region. Is reacted to form a thin film, thereby forming a thin film having an intermediate refractive index. At this time, a thin film is formed on one surface of the substrate to offset the curvature of the substrate due to the stress of the thin film formed on the opposite surface, but the thin film formed on the opposite surface of the substrate. The thickness is determined based on the type and thickness of the thin film formed on one surface of the substrate. As described above, since the stress of the thin film is determined by the type and film thickness of the thin film to be formed, when the type and film thickness of the thin film formed on one surface of the base are set, the base is determined based on this. The film thickness of the thin film formed on the opposite surface is also determined. Therefore, by adjusting the film thickness of the thin film formed on one side of the substrate, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film. In addition, as in the conventional thin film forming method, after the thin film is formed on one surface of the substrate, the substrate is inverted by forming the thin film on the opposite surface by inverting the substrate. It is possible to provide an optical product having excellent optical characteristics with a small curvature.
Further, according to the thin film forming method of the second aspect, the thin film is formed almost simultaneously on the opposite surface while forming the thin film on the one surface of the substrate. For this reason, since the thin films are stacked while canceling the stress of the thin film formed on the surface of the base, it is possible to form the thin film while keeping the base substantially flat. Accordingly, the present invention provides an optical product having superior optical characteristics in which the substrate is less bent by the stress of the thin film than the conventional thin film forming method in which the curved substrate is inverted by forming the thin film and the thin film is formed on the back surface. It becomes possible.

  Further, according to the thin film forming method of claim 3, in addition to the requirements of claim 1 or 2, the film thickness is determined by setting power supplied to each target installed in the film forming process region, from each target. At least one of setting of the opening degree of the shielding plate for shielding the film raw material supplied to the substrate and setting of the flow rate of the gas supplied to each film forming process region for each target is set. It is good to set by.

  Thus, according to the thin film forming method of claim 3, a desired power can be obtained by adjusting at least one of the power supplied to the target, the opening of the shielding plate, and the flow rate of the gas supplied to the film forming process region. A thin film having a film thickness can be formed. Therefore, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film.

  According to the thin film forming apparatus of claim 4, the intermediate thin film is formed on the substrate by performing sputtering on the target disposed in the film forming process area in the vacuum container, and the reaction process in the vacuum container is performed. A thin film forming apparatus for forming a thin film by reacting the intermediate thin film with a reactive gas in a region, the base holder being installed in the vacuum vessel and holding the base, and disposed on one side of the base holder A first film-forming process region for forming an intermediate thin film on one surface of the substrate, and the first film-forming process region on the opposite side of the substrate, with the substrate holder interposed therebetween. A second film-forming process region for forming an intermediate thin film on the surface, and the intermediate thin film formed on one surface of the substrate, which is spatially separated from the first film-forming process region, reacts with the reactive gas. To form a thin film A first reaction process region is disposed on the opposite side of the first reaction process region across the substrate holder, and an intermediate thin film formed on the surface opposite to the substrate is reacted with a reactive gas. A second reaction process region for forming a thin film, and in the second film formation process region and the second reaction process region, a thin film that cancels the curvature of the substrate due to the thin film formed on the one surface The second film forming process so that the film thickness of the thin film formed on the opposite surface is determined based on the type and film thickness of the thin film formed on the one surface of the substrate. This is solved by controlling the area and the second reaction process area.

Thus, according to the thin film forming apparatus of claim 4, the first and second film forming process regions are provided on both sides of the substrate holder to form the intermediate thin film on both surfaces of the substrate. The thin film is formed by reacting the thin film with a reactive gas. At this time, the thin film formed on the opposite surface of the substrate was formed on one surface of the substrate to cancel the curvature of the substrate due to the stress of the thin film formed on one surface of the substrate. The second film formation process region and the second reaction process region are controlled so as to be determined and formed based on the type and film thickness of the thin film. As described above, since the stress of the thin film is determined by the type and film thickness of the thin film to be formed, when the type and film thickness of the thin film formed on one surface of the base are set, the base is determined based on this. The film thickness of the thin film formed on the opposite surface is also determined. Therefore, by adjusting the film thickness of the thin film formed on one side of the substrate, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film. Then, as in a conventional thin film forming apparatus, after the thin film is formed on one surface of the substrate, the trouble of reversing the substrate and forming a thin film on the opposite surface is eliminated, and the substrate due to the stress of the thin film It is possible to provide an optical product having excellent optical characteristics with a small curvature.
According to the thin film forming apparatus of the fourth aspect, the thin film is formed on the opposite surface while the thin film is formed on the one surface of the substrate. For this reason, since the thin films are stacked while canceling the stress of the thin film formed on the surface of the base, it is possible to form the thin film while keeping the base substantially flat. Accordingly, the present invention provides an optical product having superior optical characteristics in which the substrate is less bent by the stress of the thin film as compared with the conventional thin film forming apparatus that inverts the curved substrate by forming the thin film and forms the thin film on the back surface. It becomes possible.

  According to the thin film forming apparatus of claim 5, the intermediate thin film is formed on the substrate by performing sputtering on the target disposed in the film forming process region in the vacuum container, and the reaction process in the vacuum container is performed. A thin film forming apparatus for forming a thin film by reacting the intermediate thin film with a reactive gas in a region, the base holder being installed in the vacuum vessel and holding the base, and disposed on one side of the base holder A first film-forming process region for forming an intermediate thin film on one surface of the substrate, and the first film-forming process region on the opposite side of the substrate, with the substrate holder interposed therebetween. A second film forming process region for forming an intermediate thin film on the surface, and a region spatially separated from the first film forming process region and the second film forming process region; and Deposition process area A third film formation process region formed on the same side as the first film formation region and a region spatially classified as the first to third film formation process regions. A fourth film formation process region disposed on the opposite side of the film process region; and an intermediate thin film spatially separated from the first to fourth film formation process regions and formed on one surface of the substrate. A first reaction process region that reacts with a reactive gas to form a thin film; and the first to fourth film formation process regions and the first reaction process region are spatially separated from each other; A second reaction process region formed on the opposite side of the first reaction process region across the holder and forming a thin film by reacting an intermediate thin film formed on the opposite surface of the substrate with a reactive gas A second film forming process. A thin film formed on the opposite side of the thin film that cancels the curvature of the substrate by the thin film formed on the one surface in the region, the fourth film formation process region, and the second reaction process region The second film-forming process region, the fourth film-forming process region, and the second so that the thickness is determined and formed based on the type and film thickness of the thin film formed on one surface of the substrate. This is solved by controlling the reaction process area.

Thus, according to the thin film forming apparatus of claim 5, two kinds of intermediate thin films having different refractive indexes are formed on both surfaces of the substrate in the film forming process region, and the intermediate thin film reacts with the reactive gas in the reaction process region. By forming a thin film, a thin film having an intermediate refractive index is formed. At this time, the thin film formed on the opposite surface of the substrate was formed on one surface of the substrate to cancel the curvature of the substrate due to the stress of the thin film formed on one surface of the substrate. The second film forming process region, the fourth film forming process region, and the second reaction process region are controlled so as to be determined and formed based on the type and film thickness of the thin film. As described above, since the stress of the thin film is determined by the type and film thickness of the thin film to be formed, when the type and film thickness of the thin film formed on one surface of the base are set, the base is determined based on this. The film thickness of the thin film formed on the opposite surface is also determined. Therefore, by adjusting the film thickness of the thin film formed on one side of the substrate, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film.
In addition, as in the conventional thin film forming apparatus, after forming a thin film on one surface of the substrate, the substrate is reversed by the stress of the thin film while eliminating the trouble of inverting the substrate and forming a thin film on the opposite surface. It is possible to provide an optical product having excellent optical characteristics with a small curvature.
Further, according to the thin film forming apparatus of the fifth aspect, the thin film is formed on one surface of the base while the thin film is formed on the other surface. For this reason, since the thin films are stacked while canceling the stress of the thin film formed on the surface of the base, it is possible to form the thin film while keeping the base substantially flat. Accordingly, the present invention provides an optical product having superior optical characteristics in which the substrate is less bent by the stress of the thin film as compared with the conventional thin film forming apparatus that inverts the curved substrate by forming the thin film and forms the thin film on the back surface. It becomes possible.

Furthermore, according to the thin film forming apparatus of the sixth aspect, in addition to the requirements of the third or fourth aspect, the film thickness of the thin film that cancels the curvature of the substrate is the power supply to each target installed in the film forming process region. At least one of setting, setting of an opening degree of a shielding plate that shields a film raw material supplied from each target toward the substrate, and setting a flow rate of gas supplied from each target to each film forming process region It is preferable to be configured to be set by such determination.
As described above, according to the thin film forming apparatus of the sixth aspect, it is possible to adjust at least one of the power supplied to the target, the opening of the shielding plate, and the flow rate of the gas supplied to the film forming process region. It is possible to form a thin film having a film thickness of. Therefore, it is possible to easily obtain an optical product having excellent optical characteristics with less bending of the substrate due to the stress of the thin film.

According to the thin film forming method and the thin film forming apparatus of the present invention, the thin film that cancels the curvature of the substrate due to the stress of the thin film formed on one surface of the substrate is formed on the opposite surface. For this reason, it becomes possible to provide an optical product having excellent optical characteristics with less curvature of the substrate due to the stress of the thin film.
Further, according to the thin film forming method and the thin film forming apparatus of the present invention, the thin film is formed on one surface of the substrate while the thin film is formed on the opposite surface. That is, since the thin films are stacked while canceling the stress of the thin film formed on the surface of the substrate, it is possible to form the thin film while keeping the substrate substantially flat. Therefore, it is possible to provide an optical product having excellent optical characteristics.

  Embodiments of the present invention will be described below with reference to the drawings. It should be noted that members, arrangements, and the like described below do not limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

1 to 3 show an embodiment of the present invention. FIG. 1 is a partial sectional view of the thin film forming apparatus according to the present invention as viewed from above. FIG. 2 shows the thin film forming apparatus of FIG. FIG. 3 is a partial cross-sectional view of the thin film forming apparatus of FIG. 4 is a partial cross-sectional view of a thin film forming apparatus according to another embodiment of the present invention as viewed from above, and FIG. 5 is a partial cross-sectional view of the thin film formation apparatus according to another embodiment of the present invention as viewed from above. These are the fragmentary sectional views which looked at the thin film formation apparatus in other embodiments of the present invention from the side.
The magnetron sputter electrodes 32 and 52 and the antenna 71 are not originally visible in the top views of FIGS. 1, 4 and 5, but are shown by dotted lines in the drawings for easy understanding of the invention. It is.

  In this embodiment, a thin film forming apparatus that performs magnetron sputtering, which is an example of sputtering, is used. However, the type of sputtering is not limited to such magnetron sputtering, and bipolar sputtering that does not use magnetron discharge or the like. A known thin film forming apparatus that performs sputtering can also be used.

  In the thin film forming apparatus 1 of the present embodiment, a thin film having a target thickness can be formed on a substrate by repeatedly forming a thin film having a thickness smaller than the target thickness by sputtering and performing plasma treatment. In the present embodiment, a thin film forming process for forming a thin film having an average thickness of 0.01 to 1.5 nm on the substrate surface by sputtering and plasma processing is repeated for each rotation of the substrate holder 13, so that the desired number of nm to A thin film having a thickness of about several hundred nm is formed.

  As shown in FIGS. 1 and 2, the thin film forming apparatus 1 of the present embodiment includes a vacuum vessel 11, a substrate holder 13, a motor 17, a first sputtering unit 20A, a second sputtering unit 30A, The third sputtering unit 40A, the fourth sputtering unit 50A, the first plasma generation unit 60A, and the second plasma generation unit 70A are provided as main components.

  The vacuum vessel 11 is made of stainless steel, which is usually used in a known thin film forming apparatus, and is a polygonal hollow body. An entrance / exit 11 d for carrying in / out the substrate holder 13 is formed on the side wall of the vacuum vessel 11. The entrance / exit 11d is formed in such a size that a substrate holder 13 (to be described later) can be taken in and out of the inside of the vacuum vessel 11, and a door 16 having a size capable of covering the entrance / exit 11d is provided on a wall surface outside the entrance / exit 11d. Is provided. A door storage container (not shown) for storing the door 16 is connected above the vacuum container 11, and the door 16 opens and closes by sliding between the interior of the vacuum container 11 and the interior of the door storage chamber. . An elastic member (not shown) such as rubber is provided between the outer wall of the vacuum vessel 11 and the door 16 to keep the inside of the vacuum vessel 11 airtight.

In addition, although the single chamber system provided with one vacuum chamber is employ | adopted for the vacuum vessel 11 of this embodiment, what provided the load lock chamber outside the entrance / exit 11d is also employable. In a thin film forming apparatus employing such a load lock chamber, it is possible to carry in / out the substrate while maintaining the vacuum state in the vacuum vessel, so the vacuum vessel is deaerated each time the substrate is carried out. Thus, it is possible to save the time and effort to form a vacuum, and the film forming process can be performed with high work efficiency.
It is also possible to employ a multi-chamber system that includes a plurality of vacuum chambers and can form a thin film independently in each vacuum chamber.

  Three openings for exhaust are provided on the wall surface of the vacuum vessel 11 and are connected to the pipes 15a, 15b, and 15c, respectively. These pipes are connected to a vacuum pump (not shown) for exhausting the inside of the vacuum vessel 11. An opening 11a is provided between a first film forming process region 20 and a second film forming process region 30, which will be described later, and a first reaction process region 60 and a second reaction process region 70. 15a communicates with the inside of the vacuum vessel 11 through the opening 11a.

  Further, an opening 11b is provided between a third film forming process region 40 and a fourth film forming process region 50, which will be described later, and a first reaction process region 60 and a second reaction process region 70. The pipe 15b communicates with the inside of the vacuum vessel 11 through the opening 11a. Moreover, the opening 11c is provided in the wall surface located in the side surface of the 1st reaction process area | region 60 and the 2nd reaction process area | region 70, and the piping 15c is connected with the inside of the vacuum vessel 11 through the opening 11c.

  The substrate holder 13 is a disk-shaped member for holding the substrate S in the vacuum vessel 11, and corresponds to the substrate holder of the present invention. The substrate holder 13 includes a plurality of circular openings for holding the substrate S, and each of the substrates S is accommodated in the openings. The substrate S held in the opening is held by the holding tool 13a so as not to drop off. The holder 13a is a donut-shaped member having an opening inside, and is formed so that the diameter of the opening is smaller than the diameter of the substrate S.

Screw holes are formed in two places on the holder 13a, and screw holes are also provided at positions corresponding to the screw holes of the holder 13a on the periphery of the opening of the substrate holder 13. After being accommodated in the opening of the substrate holder 13, the substrate S is held by being held from both sides by the holder 13a. The holder 13a is fixed to the substrate holder 13 by bolts 13b.
Note that the substrate holder is not limited to a disk-like one as in the present embodiment, and may be, for example, a plate-like one.

  The substrate holder 13 is configured to be movable between the inside of the vacuum vessel 11 and the outside of the vacuum vessel 11. In the present embodiment, a rail (not shown) is installed on the side surface of the vacuum vessel 11, and the substrate holder 13 is transported along the rail to the central portion inside the vacuum vessel 11. The substrate holder 13 is placed on the rail outside the vacuum vessel 11, passes through the inlet / outlet 11 d, and is carried into the central portion in the vacuum vessel 11.

  A lower support member 14-1 and an upper support member 14-2 for holding the substrate holder 13 are provided on the center lower surface and the center upper surface of the inner wall of the vacuum vessel 11, respectively. The lower support member 14-1 is installed at the center of the lower inner wall of the vacuum vessel 11, and the upper support member 14-2 is installed at the center of the upper inner wall of the vacuum vessel 11.

  The lower support member 14-1 is provided with a plurality of protrusions 14-1a. The protrusion 14-1a includes a circular protrusion disposed at the center and a plurality of claw-shaped protrusions disposed around the protrusion. The protrusion 14-1a is fixed to a lower portion of a hydraulic cylinder 14-1b provided in the lower support member 14-1, and moves up and down when the hydraulic cylinder 14-1b is driven by a hydraulic pump (not shown). It is possible. Similarly, the upper support member 14-2 is also provided with a protrusion 14-2a.

  Similar to the lower support member 14-1, the protrusion 14-2a of the upper support member 41-2 is composed of a circular protrusion disposed at the center and a plurality of claw-shaped protrusions disposed around the protrusion. Is done. The protrusion 14-2a is fixed to an upper portion of a hydraulic cylinder 14-2b provided in the upper support member 14-1, and can be moved up and down by being driven by a hydraulic pump (not shown). It has become.

  On the other hand, a plurality of recesses are formed on both sides of the substrate holder 13 at the center of the substrate holder 13. The recess is formed of a circular recess at the center of the substrate holder 13 and a plurality of small recesses arranged around the recess, and the recesses are respectively formed on the lower support member 14-1 and the upper support member 14-2. The plurality of protrusions 14-1a and protrusions 14-2a are provided to be engaged with each other.

  The substrate holder 13 carried into the central portion of the vacuum vessel 11 is installed in the vacuum vessel 11 by being sandwiched between the lower support member 14-1 and the upper support member 14-2. The protrusion 14-1 a of the lower support member 14-1 is moved upward by the hydraulic cylinder 14-1 b and is engaged with a recess provided in the center portion of the lower surface of the substrate holder 13. Further, the protrusion 14-2a of the upper support member 14-2 is moved downward by the hydraulic cylinder 14-2b, and engages with a recess provided at the center of the upper surface of the substrate holder 13. The protrusions 14-1a and 14-2a are biased toward the substrate holder 13 by the respective hydraulic cylinders, and the lower support member 14-1 and the upper support member 14-2 cooperate to prevent the substrate holder 13 from falling off. Thus, the substrate holder 13 is pinched.

  A motor 17 is provided on the outside lower side of the vacuum vessel 11. The rotating shaft 17a of the motor 17 penetrates the lower wall surface of the vacuum vessel 11 and is connected to the lower support member 14-1. The substrate holder 13 rotates around the rotation shaft 17a by driving a motor 17 provided in the lower part of the vacuum vessel 11 while maintaining the vacuum state in the vacuum vessel 11. Since each board | substrate S is hold | maintained on the board | substrate holder 13, when the board | substrate holder 13 rotates, it revolves around the rotating shaft 17a. The joint between the rotating shaft 17a and the lower support member 14 is formed of an insulating member. As a result, abnormal discharge in the substrate can be prevented.

  The substrate S corresponds to the substrate of the present invention. The substrate S is a glass disk-like member, and a thin film is formed on the surface thereof by a thin film forming process. The substrate is not limited to a disk-like one as in this embodiment, and a lens-like one or a tubular one can also be used. The material of the substrate S is not limited to glass as in the present embodiment, and may be, for example, quartz, sapphire, silicon, germanium, plastic, or the like.

  Next, the first sputtering unit 20A, the second sputtering unit 30A, the third sputtering unit 40A, and the fourth sputtering unit 50A that form a thin film on the surface of the substrate S will be described. In the thin film forming apparatus 1 of this example, the film forming process regions (20, 30, 40, 50) are provided with four chambers (zones), and the reaction process regions (60, 70) are provided with two chambers (zones). The film formation process regions 20, 30, 40, and 50 are provided for performing sputtering to form an intermediate thin film, and the reaction process regions 60 and 70 perform plasma treatment on the intermediate thin film to form a final thin film. It is provided for.

  Rectangular openings 11e to 11j are formed on the side wall of the vacuum vessel 11, and stainless steel partition walls 18a to 18f project from the end sides of the openings 11e to 11j toward the substrate holder 13. It is arranged. Sputtering means 20A, 30A, 40A, and 50A are provided facing the outer peripheral surface of the substrate holder 13 so as to close the openings 11e to 11h. Plasma generating means 60A and 70A are provided facing the outer peripheral surface of the substrate holder 13 so as to close the openings 11i and 11j of the vacuum vessel 11.

As described above, the film forming process region 20 is formed so as to be surrounded by the partition wall 18a having four side surfaces, the lower surface of the substrate holder 13, and the sputtering means 20A. The film formation process region 30 is formed by being surrounded by the partition wall 18b, the upper surface of the substrate holder 13, and the sputtering means 30A, and the film formation process region 40 is formed by being surrounded by the partition wall 18c, the lower surface of the substrate holder 13, and the sputtering means 40A. The film formation process region 50 is formed so as to be surrounded by the partition wall 18d, the upper surface of the substrate holder 13, and the sputtering means 50A.
The reaction process region 60 is formed so as to be surrounded by the partition wall 18e, the lower surface of the substrate holder 13, and the plasma generating means 60A. The reaction process region 70 is formed by being surrounded by the partition wall 18f, the upper surface of the substrate holder 13, and the plasma generating means 60A.

  As described above, the film formation process regions 20, 30, 40, and 50 and the reaction process regions 60 and 70 are formed in spatially separated regions. In the present embodiment, as shown in FIGS. 1 and 2, the film forming process region 20, the film forming process region 40, and the reaction process region 60 are disposed below the vacuum vessel 11, respectively. Further, the film forming process region 30, the film forming process region 50, and the reaction process region 70 are respectively disposed on the upper side of the vacuum vessel 11.

  In addition, the film formation process region 20 and the film formation process region 30 are disposed at substantially opposite positions with the substrate holder 13 interposed therebetween. In addition, the film formation process region 40 and the film formation process region 50 are disposed at substantially opposing positions with the substrate holder 13 interposed therebetween. Further, the reaction process region 60 and the reaction process region 70 are arranged at positions substantially facing each other with the substrate holder 13 interposed therebetween. However, the positions of the film forming process regions 20 and 40 and the reaction process region 70 are not limited to the positions substantially opposite to the film forming process regions 30 and 50 and the reaction process region 60 as described above, and are arranged at slightly shifted positions. It may be.

  The film forming process regions 40 and 50 are provided at positions rotated about 90 degrees from the film forming process regions 20 and 30 around the central axis of the substrate holder 13. The reaction process regions 60 and 70 are formed at positions that are rotated about 90 degrees from the film formation process regions 20 and 30 about the central axis of the substrate holder 13 and about the central axis Z of the substrate holder 13. It is provided at a position facing the film process regions 20 and 30.

  When the substrate holder 13 is rotated by the motor 17, the substrate S held on the plate surface of the substrate holder 13 revolves, and the lower surface side of the substrate S is sputtered 20A, 40A (deposition process regions 20, 40). Between the position facing the surface and the position facing the plasma generating means 60A (reaction process region 60) in this order. Further, the upper surface side of the substrate S is in this order between the position facing the sputtering means 30A, 50A (deposition process regions 30, 50) and the position facing the plasma generating means 70A (reaction process region 70) in this order. Repeatedly rotate.

  Pipes from a sputtering gas cylinder 27 that stores an argon gas as an inert gas and a reactive gas cylinder 29 that stores a reactive gas are led to the film forming process area 20. The gas and the reactive gas can be supplied. The flow rate of the inert gas from the sputtering gas cylinder 27 and the flow rate of the reactive gas from the reactive gas cylinder 29 are adjusted by the mass flow controllers 26 and 28, respectively.

  The film formation process areas 30, 40, and 50 are configured in the same manner as the film formation process area 20, and a sputtering gas cylinder 37, a reactive gas cylinder 39, and mass flow controllers 36 and 38 are provided in the film formation process area 30. A sputtering gas cylinder 47, a reactive gas cylinder 49, and mass flow controllers 46 and 48 are provided in the film forming process area 40, and a sputtering gas cylinder 57, a reactive gas cylinder 59, and mass flow controllers 56 and 58 are provided in the film forming process area 50. Is provided. As the reactive gas, for example, oxygen gas, nitrogen gas, fluorine gas, ozone gas or the like is used.

In the film forming process region 20, the sputtering means 20 </ b> A of the present invention is disposed so as to face the lower surface of the substrate holder 13. The sputtering means 20 </ b> A includes an AC power supply 25 connected to a pair of magnetron sputtering electrodes 22 through a transformer 24. The magnetron sputtering electrode 22 is fixed to an electrode installation plate 23 provided so as to close the opening 11e of the vacuum vessel 11 via an insulating member (not shown). A pair of targets 21 are held on the magnetron sputter electrode 22. The AC power supply 25 of this embodiment applies an alternating electric field of 1 k to 100 kHz to the target 21 held on both electrodes of the magnetron sputter electrode 22.
The target 21 of this example is formed by forming a film raw material in a flat plate shape so as to face a substrate and have a predetermined area, and is held so as to face the lower surface of the substrate holder 13. Any material can be used as the target material, for example, silicon, niobium, titanium, aluminum, germanium, or the like.

  The film forming process regions 30, 40, 50 are also configured in the same manner as the film forming process region 20, and the film forming process region 30 is provided with a sputtering means 30 A having a pair of magnetron sputter electrodes 32. Is fixed to the electrode installation plate 33 and connected to a transformer 34 and an AC power source 35. Further, as shown in FIG. 3, a sputtering means 40A having a pair of magnetron sputtering electrodes 42 is provided in the film forming process region 40, and this magnetron sputtering electrode 42 is fixed to an electrode installation plate 43, and a transformer 45 and an AC power source. 44. Further, a sputtering means 50 A having a pair of magnetron sputtering electrodes 52 is provided in the film forming process region 50, and this magnetron sputtering electrode 52 is fixed to an electrode installation plate 53 and connected to a transformer 55 and an AC power supply 54. Therefore, power can be supplied independently to each target, and thereby the film formation rate by sputtering can be independently adjusted for each target.

  Similarly to the target 21, the targets 31, 41, 51 are formed by forming a film raw material into a flat plate shape so as to face the substrate and have a predetermined area, and are held so as to face the outer peripheral surface of the substrate holder 13. Is done. For these targets, a film material is selected according to the refractive index of the thin film formed on the substrate. In practice, in the present invention, it is not always necessary to place targets in all the film forming process regions 20, 30, 40, 50, and targets made of different film raw materials are arranged in three or more film forming process regions. Then, a film formation process may be performed.

  Next, the reaction process area will be described. In the reaction process region 60, plasma processing is performed, and the intermediate thin film formed in the film formation process regions 20 and 40 is irradiated with reactive species (radicals, ions, etc.) of a reactive gas mixed with an inert gas. The thin film and the reactive species of the reactive gas are reacted to convert to a composite metal compound.

  The plasma generating means 60A is for bringing the inert gas and the reactive gas supplied to the reaction process region 60 into a plasma state. In the reaction process region 60, piping from an inert gas cylinder 67 that stores argon gas as an inert gas and a reactive gas cylinder 69 that stores reactive gas is led, and the reaction process region 60 has an inert gas. And reactive gas can be supplied. The flow rate of the inert gas from the inert gas cylinder 67 and the flow rate of the reactive gas from the reactive gas cylinder 69 are adjusted by the mass flow controllers 66 and 68.

  A mass flow controller is a device that adjusts the flow rate of a gas. The mass flow controller includes an inlet through which a gas from a gas cylinder flows in, an outlet through which the gas flows out to the vacuum vessel 11, a sensor for detecting a mass flow rate of the gas, a control valve for adjusting the gas flow rate, and an inlet. A sensor for detecting the mass flow rate of the gas that has flowed in and an electronic circuit for controlling the control valve based on the flow rate detected by the sensor are provided as main components. A desired flow rate can be set to the electronic circuit from the outside.

  The mass flow rate of the gas sent into the mass flow controller from the inlet is detected by a sensor. A control valve is provided downstream of the sensor, and the control valve compares the flow rate detected by the sensor with a set reference value and controls the control valve so that the gas flow rate approaches the reference value. .

  The plasma generating means 60 of the present embodiment includes a dielectric plate 62 provided so as to close the opening 11i, and an antenna 61 disposed in a spiral shape on the outside of the dielectric plate 62. . The dielectric plate 62 is formed of a plate-like dielectric, and is formed of quartz in this example. The dielectric plate 62 is provided so as to face the substrate holder 13 with the reaction process region 60 interposed therebetween. A case body 63 is attached to the outer wall of the opening 11 i, and the antenna 61 is housed in the case body 63. The case body 63 and the dielectric plate 62 are fixed with bolts or the like, and an O-ring or the like is provided between both members to keep the inside airtight. That is, an antenna housing chamber for housing the antenna 61 is formed.

  In the present embodiment, an exhaust pipe (not shown) is connected to the antenna accommodation chamber in order to evacuate the interior of the antenna accommodation chamber to a vacuum state. A vacuum pump (not shown) is connected to the piping, and the antenna housing chamber is in a vacuum state by the vacuum pump.

  The antenna 61 is electrically connected to a high frequency power supply 65 via a matching box 64 that accommodates a matching circuit. The antenna 61 is for receiving power from the high frequency power supply 65 to generate an induction electric field in the reaction process region 60 to generate plasma.

As the plasma generation process, first, a vacuum pump (not shown) is operated to depressurize the inside of the vacuum vessel 11 to about 10-2 Pa to 10 Pa, and while maintaining a predetermined vacuum state, Reactive gas is introduced into the vacuum vessel 11. Thereafter, adjustment or the like is appropriately performed so that the inside of the vacuum vessel 11 maintains 10-2 Pa to 10 Pa.
Then, in a state where the inside of the vacuum vessel 11 is maintained at the predetermined pressure, a voltage of 13.56 MHz is applied from the high frequency power supply 65 to the antenna 61 to generate plasma. In this way, plasma is generated in the reaction process region 60, and plasma processing is performed on the thin film on the substrate held by the substrate holder 13 by this plasma.

  Similarly, the reaction process region 70 is subjected to plasma treatment, and the intermediate thin film formed in the film formation process regions 20 and 40 is irradiated with active species (radicals, ions, etc.) of a reactive gas mixed with an inert gas. Then, the intermediate thin film and the active species of the reactive gas are reacted to convert to a composite metal compound.

Similarly, the plasma generating means 70A of the present embodiment is also provided with a dielectric plate 72 provided so as to close the opening 11j, and an antenna 71 disposed in a spiral shape outside the dielectric plate 72. Has been. A case body 73 is attached to the outer wall of the opening 11 i, and the antenna 71 is housed in the case body 73. The case body 73 and the dielectric plate 72 are fixed with bolts or the like, and an antenna accommodating chamber is formed.
The antenna housing chamber is provided with an inert gas cylinder 77 for storing argon gas as an inert gas, and mass flow controllers 76 and 78 for adjusting the flow rates of the respective gases. It is introduced into the antenna accommodation room.

Next, a process for forming a mixed film using the thin film forming apparatus 1 will be described.
In the thin film forming apparatus 1 of the present example, there are four film forming process regions 20, 30, 40, and 50 as described above, and targets 21, 31, 41, and 51 made of different materials can be arranged on these, respectively. It is. A mixed film made of a plurality of optical materials can be formed on the substrate by the plurality of targets.

  Here, of the four film forming process regions 20, 30, 40, 50, the same material (film raw material) is used for the film forming process regions 20, 30, and the same material is used for the film forming process regions 40, 50. The case will be described. Specifically, an example in which silicon (Si) is used as the low refractive index film forming material for the targets 21 and 31 and niobium (Nb) is used as the high refractive index film material for the targets 41 and 51 will be described. In this embodiment, a thin film having an intermediate refractive index is formed by alternately stacking silicon, which is a low refractive index material, and niobium, which is a high refractive index material. A thin film having an intermediate refractive index is simultaneously formed on both surfaces of the substrate, and finally a thin film having substantially the same film thickness is formed on both surfaces of the substrate.

  First, as the film thickness setting step, the film thickness and refractive index of the thin film formed on one surface of the substrate S are arbitrarily set. In accordance with the set film thickness, conditions for determining the supply amount of the film raw material supplied from the targets 21, 31, 41, 51 toward the substrate are set. Conditions for determining the supply amount are the magnitude of power supplied to each target, the film formation time, the area ratio of the target, and the like.

  Subsequently, the targets 21, 31, 41, 51 are held on the magnetron sputtering electrodes 22, 32, 42, 52 as a thin film forming step. In this state, the inside of the vacuum vessel 11 is brought to a vacuum state of about 10-2 Pa to 10 Pa. Then, the substrate S is held on the substrate holder 13 outside the vacuum vessel 11. Subsequently, the substrate holder 13 is placed on a rail (not shown) and carried into the central portion of the vacuum vessel 11. When it moves to a predetermined position in the vacuum vessel 11, the hydraulic cylinders 14-1b and 14-2b of the lower support member 14-1 and the lower support member 14-2 are driven, and the protrusions 14-1a and 14 are respectively driven. -2a is engaged with a recess formed in the center of the substrate holder 13. Next, the door 16 is closed and the vacuum pump is operated to evacuate the inside of the vacuum vessel 11 to obtain a vacuum state of about 10-2 Pa to 10 Pa.

  The inside of the vacuum vessel 11 is depressurized to the above-described predetermined pressure, and in this state, the motor 17 is operated to rotate the substrate holder 13. Thereafter, after the pressure inside the vacuum vessel 11 is stabilized, the pressure in the film forming process region 20 is adjusted to 1.0 × 10 −1 Pa to 1.3 Pa.

  Next, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are adjusted from the sputtering gas cylinder 27 and the reactive gas cylinder 29 to the film forming process region 20 while the mass flow controllers 26 and 28 adjust the flow rate. Then, the atmosphere for performing sputtering in the film forming process region 20 is adjusted. Next, sputtering is performed on the target 21 by applying an AC voltage having a frequency of 1 to 100 KHz from the AC power source 25 to the magnetron sputtering electrode 22. By sputtering, the film material is supplied from the target 21 toward the substrate substantially in proportion to the area. As a result, an intermediate thin film made of silicon or incomplete silicon oxide (SiOx (0 <x <2)) is formed on the film forming surface of the substrate (intermediate thin film forming step).

  On the film forming surface of the substrate, an intermediate thin film is formed when passing through a position facing the magnetron sputtering electrode 22 (that is, a position facing the target 21) as the substrate holder 13 rotates.

  At the same time as forming an intermediate thin film of silicon or incomplete silicon oxide in the film forming process region 20, an intermediate thin film of silicon or incomplete silicon oxide is formed in the film forming process region 30 by the same operation. In forming the thin film in the film formation process region 30, first, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are mass-flowed from the sputtering gas cylinder 37 and the reactive gas cylinder 39 to the film formation process region 30. The controller 36, 38 guides the flow rate while adjusting the atmosphere for sputtering in the film forming process region 30. Next, sputtering is performed on the target 31 by applying an AC voltage having a frequency of 1 to 100 KHz from the AC power source 35 to the magnetron sputtering electrode 32.

  Next, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are adjusted from the sputtering gas cylinder 27 and the reactive gas cylinder 29 to the film forming process region 20 while the mass flow controllers 26 and 28 adjust the flow rate. Then, the atmosphere for performing sputtering in the film forming process region 20 is adjusted. Next, sputtering is performed on the target 21 by applying an AC voltage having a frequency of 1 to 100 KHz from the AC power source 25 to the magnetron sputtering electrode 22. By sputtering, the film material is supplied from the target 21 toward the substrate substantially in proportion to the area. As a result, an intermediate thin film made of silicon or incomplete silicon oxide (SiOx (0 <x <2)) is formed on the film forming surface of the substrate (intermediate thin film forming step).

  Next, the film forming process areas 40 and 50 will be described. In the film forming process region 40, an intermediate thin film of niobium or incomplete niobium oxide is formed. At the same time as the intermediate thin film is formed in the film formation process region 40, an intermediate thin film of niobium or incomplete niobium oxide is formed in the film formation process region 50 by the same operation. In forming the thin film in the film formation process region 40, first, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are mass-flowed from the sputtering gas cylinder 47 and the reactive gas cylinder 49 to the film formation process region 40. The controller 46, 48 guides the flow rate while adjusting the atmosphere for performing sputtering in the film forming process region 40. Next, sputtering is performed on the target 41 by applying an AC voltage having a frequency of 1 to 100 KHz from the AC power source 44 to the magnetron sputtering electrode 42.

  Subsequently, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are adjusted from the sputtering gas cylinder 47 and the reactive gas cylinder 49 to the film forming process region 40 while adjusting the flow rate by the mass flow controllers 46 and 48. Then, the atmosphere for performing sputtering in the film forming process region 40 is adjusted. Next, sputtering is performed on the target 41 by applying an AC voltage having a frequency of 1 to 100 KHz from the AC power source 44 to the magnetron sputtering electrode 42. By sputtering, the film material is supplied from the target 41 toward the substrate substantially in proportion to the area. Thereby, an intermediate thin film made of niobium or incomplete niobium oxide is formed on the film forming surface of the substrate (intermediate thin film forming step).

  On the film forming surface of the substrate, an intermediate thin film is formed when passing through a position facing the magnetron sputtering electrode 42 (that is, a position facing the target 21) as the substrate holder 13 rotates.

  At the same time as forming an intermediate thin film of silicon or incomplete silicon oxide in the film forming process region 40, an intermediate thin film of silicon or incomplete silicon oxide is also formed in the film forming process region 50 by the same operation. In forming the thin film in the film forming process region 50, first, argon gas, which is an inert gas for sputtering, and oxygen gas, which is a reactive gas, are mass-flowed from the sputtering gas cylinder 57 and the reactive gas cylinder 59 to the film forming process region 50. The controller 56, 58 guides the flow rate while adjusting the atmosphere for performing sputtering in the film forming process region 50.

  Next, sputtering is performed on the target 51 by applying an AC voltage having a predetermined frequency from the AC power source 54 to the magnetron sputtering electrode 52. Here, the frequency of the AC voltage to be applied is preferably 10 k to 1 MHz. This is because abnormal discharge tends to occur when the frequency of the applied AC voltage is lower than 10 kHz, and it is difficult to stably form a thin film. On the other hand, if it is higher than 1 MkHz, it is difficult to adjust the film forming rate by the matching box, which is not preferable.

  Next, plasma processing in the reaction process regions 60 and 70 will be described. In the reaction process region 60, oxygen gas is introduced as a reactive gas from a reactive gas cylinder 69, and argon gas is introduced as an inert gas from an inert gas cylinder 67. A high frequency voltage of 13.56 MHz is applied to the antenna 61, and plasma is generated in the reaction process region 60 by the plasma generating means 60A. At this time, the pressure in the reaction process region 60 is maintained at 0.7 × 10 −1 to 1.0 Pa.

As the substrate holder 13 rotates, the substrate S on which the intermediate thin film is formed by the targets 21, 31, 41, 51 passes through the reaction process region 60. In the reaction process region 60, the intermediate thin film is oxidized by plasma treatment. A reaction process is performed.
That is, plasma of oxygen gas is generated in the reaction process region 60 by the plasma generating means 60A, and, for example, silicon or incomplete silicon oxide formed in the film forming process region 20 is oxidized with this oxygen gas plasma, and desired. To incomplete silicon oxide or silicon oxide of the composition Further, niobium or incomplete niobium oxide formed in the film forming process region 40 is oxidized to be converted into incomplete niobium oxide or niobium oxide having a desired composition. Thereby, the final thin film which is a mixed film is formed on a board | substrate (final thin film formation process).

  As described above, when the substrate is rotated in the vacuum vessel 11, silicon or incomplete silicon oxide is formed on the substrate surface in the film formation process regions 20 and 30, and niobium or non-oxide is formed on the substrate surface in the film formation process regions 40 and 50. An intermediate thin film in which complete niobium oxide is laminated is formed, and in the reaction process regions 60 and 70, the formed intermediate thin film is subjected to plasma treatment to form a final thin film that is a mixed film. Accordingly, the final thin film is gradually laminated as the substrate rotates, and a film having a desired film thickness can be obtained by performing the film forming process for a predetermined time.

The plasma treatment in the reaction process region is performed simultaneously on both intermediate thin films after the formation of the intermediate thin film in the film formation process regions 20 and 30 and the formation of the intermediate thin film in the film formation process regions 40 and 50. Plasma processing may be performed in the process regions 60 and 70. However, after forming the intermediate thin film in the film formation process regions 20 and 30, the reaction process region 60 is not formed in the film formation process regions 40 and 50 without forming the intermediate thin film. , 70 may perform plasma treatment. Alternatively, the intermediate thin film may not be formed in the film forming process regions 20 and 30, and the intermediate thin film may be formed in the film forming process regions 40 and 50 and then the plasma process may be performed in the reaction process regions 60 and 70.
As described above, it is possible to form a thin film having a desired refractive index by controlling the thickness of the intermediate thin film formed in the film forming process region.

  Here, the deposition process region and the reaction process region are controlled on one surface of the substrate S so as to form a thin film that cancels the curvature of the substrate due to the internal stress of the thin film formed on the opposite surface. Thin film formation is performed. For example, when the same kind of thin film is formed on both surfaces of the substrate S, if the thin film is formed so that the thickness of the thin film formed on both surfaces of the substrate S is the same, the internal stress of the thin film formed on both surfaces of the substrate S The curvature of the substrate due to is canceled out. Accordingly, the curvature of the substrate due to the internal stress of the thin film is minimized.

  On the other hand, when different types of thin films are formed on both surfaces of the substrate S, the thickness of the thin film formed on the opposite surface depends on the type and thickness of the thin film formed on one surface of the substrate S. It is determined. For example, when creating a bandpass filter, a short wavelength transmission filter is formed on one surface of the substrate S, and a long wavelength transmission filter is formed on the opposite surface. In this case, for example, when a short wavelength transmission filter made of a thin film (Nb2O5 / SiO2 film thickness ratio 0.56) in which Nb2O5 and SiO2 are laminated is formed on one surface of the substrate S, the opposite side of the substrate S is formed. If a long-wavelength transmission filter made of a thin film (Nb2O5 / SiO2 film thickness ratio 0.17) in which Nb2O5 and SiO2 are laminated is formed on this surface, the curvature of the substrate due to the internal stress of both thin films is canceled out. It becomes. Accordingly, the curvature of the substrate due to the internal stress of the thin film is minimized.

  The film thickness is adjusted by adjusting the power supplied to each target installed in the film forming process area. That is, by adjusting the power supplied from the AC power source 25 shown in FIGS. 1 and 2 to the transformer 24, the power supplied to the target installed in the film forming process region 20 is adjusted, and the target is transferred from the target to the substrate S. It is possible to adjust the amount of the film raw material adhering. For example, when the power supplied from the AC power supply 25 to the transformer 24 increases, the power supplied to the target increases, and the amount of film raw material flying from the target to the substrate S increases. Conversely, when the power supplied from the AC power supply 25 to the transformer 24 is reduced, the power supplied to the target is reduced, and the amount of film raw material flying from the target to the substrate S is reduced. In this way, by adjusting the electric power supplied from the AC power supply 25 to the transformer 24, a thin film having a desired film thickness can be formed on the substrate surface.

  Similarly, by adjusting the power supplied from the AC power supplies 35, 45, 55 to the transformers 34, 44, 54, the power supplied to the targets installed in the film forming process regions 30, 40, 50 is adjusted. This makes it possible to adjust the amount of film raw material attached to the substrate S from each target. Thereby, a thin film having a desired film thickness can be formed.

  It is also possible to adjust the film thickness of the thin film formed on the substrate surface by providing a shielding plate for shielding the film raw material between the target and the substrate S and adjusting the opening of the shielding plate. is there. For example, in the thin film forming apparatus of FIG. 6, a shielding plate 81 is provided between the substrate S and the target 21. The shielding plate 81 is connected to a rotating shaft of a motor 83 provided outside the vacuum vessel 11 via a rotating shaft 82. Therefore, the area for shielding the front surface of the target 21 can be adjusted by rotating the motor 83 to move the position of the shielding plate 81. That is, by driving the motor 83 and adjusting the opening degree of the shielding plate 81, the amount of film raw material adhering to the surface of the substrate S can be adjusted. Thereby, a thin film having a desired film thickness can be formed.

Similarly, in the film forming process region 30, a shielding plate 91 is provided between the substrate S and the target 31, and the shielding plate 91 is connected to the motor 93 via the rotation shaft 92. By adjusting the opening degree of the shielding plate 91, a thin film having a desired film thickness can be formed.
In addition, although not shown in the drawing, it is possible to adjust the film thickness formed on the surface of the substrate by providing a shielding plate between the target and the substrate S in the film forming process regions 40 and 50 as well.

Furthermore, the film thickness of the thin film formed on the substrate surface can be adjusted by adjusting the flow rate of the gas supplied to each film forming process region. For example, a sputtering gas such as an argon gas is supplied from the sputtering gas cylinder 27 and a reactive gas such as an oxygen gas is supplied from the reactive gas cylinder 29 to the film forming process region 20, and the gas flow rate is controlled by the mass flow controllers 26 and 28, respectively. By adjusting, it is possible to adjust the flow rate of the gas supplied to the film forming process region 20, thereby adjusting the film thickness of the thin film formed on the substrate surface.
In order to adjust the gas flow rate by the mass flow controller, the operator can adjust the gas flow rate by setting a desired flow rate in an electronic circuit provided in the mass flow controller.

  In the thin film forming apparatus of the present invention, intermediate thin film formation in the film forming process regions 20 and 30, intermediate thin film formation in the film forming process regions 40 and 50, and final thin film formation in the reaction process regions 60 and 70 are simultaneously performed. By doing so, the curvature of the substrate caused by the internal stress caused by the thin film formed on one surface of the substrate is offset by the curvature caused by the internal stress of the thin film formed on the opposite surface of the substrate, and the substrate is kept flat. In this state, the thin film is formed. Therefore, compared with the prior art in which a thin film is formed on one surface of a substrate and then the substrate is inverted to form a thin film on the opposite surface, an optical product that is less likely to be curved and has excellent optical characteristics. It becomes possible to provide.

In the above embodiment, a reactive thin film forming apparatus has been described in which a plurality of film formation process regions having targets having different refractive indexes are provided to form an intermediate thin film, and the intermediate thin film is converted into a final thin film in the reaction process region. However, the thin film forming method of the present invention can be applied not only to such a thin film forming apparatus but also to other thin film forming apparatuses. For example, as shown in FIG. 4, the present invention can also be implemented in a thin film forming apparatus that has only film formation process regions 20 and 30 and does not have a reaction process region or other film formation process regions with different types of targets. .
Further, as shown in FIG. 5, the present invention can also be implemented in a thin film forming apparatus including film forming process regions 20 and 30 provided with one type of target and reaction process regions 60 and 70.

When the process of forming a mixed film having a desired film thickness is completed, the vacuum state in the vacuum vessel 11 is released and the door 16 is opened. Then, the substrate holder 13 is carried out of the vacuum container 11.
In the thin film forming apparatus 1 of this example, two different types of film source materials can be used for the targets 21 and 31 and the targets 41 and 51, respectively, as described above. A mixed film having a refractive index can be formed.

Below, the Example which implemented the thin film formation method of this invention and formed the thin film on the board | substrate, and the comparative example with respect to this are shown. In both Examples and Comparative Examples, thin film formation was performed using a disk-shaped substrate made of optical glass having a diameter of 30 mm and a thickness of 0.3 mm.
(Example)
First, in the examples, the thin film forming apparatus 1 of this example was used, and silicon (Si) was used as the targets 21 and 31 of the film forming process regions 20 and 30 as the first film raw material. Further, niobium (Nb) was used as the target 41 and 51 in the film forming process regions 40 and 50 as the second film source material. A film forming process is performed using the vacuum apparatus, and a mixed film composed of SiO2 (refractive index: 1.46) and Nb2O5 (refractive index: 2.35) based on Si and Nb is formed on both sides of the substrate. They were formed to have substantially the same final film thickness.

The sputtering conditions of this example are as follows.
(1) Film formation process region 20 and 30 conditions Input power: 0.2 to 2 kW
Deposition process zone pressure: 0.2-2 Pa
Argon gas flow rate: 100-500 sccm
Applied AC voltage frequency: 10 to 100 kHz
(2) Film formation process region 40, 50 conditions Input power: 0.2 to 2 kW
Deposition process zone pressure: 0.2-2 Pa
Argon gas flow rate: 100-500 sccm
Applied AC voltage frequency: 10 to 100 kHz
(3) Reaction process region 60, 70 conditions Input power: 0.2-2 kW
Reaction process area pressure: 0.2 to 2 Pa
Oxygen gas flow rate: 20 to 200 sccm

(Comparative example)
In the comparative example, the intermediate thin film was formed by sputtering and the intermediate thin film was oxidized only in the film forming process regions 20 and 40 and the reaction process region 60, and the thin film was formed only on one side of the substrate. The sputtering pressure and other conditions are the same as in the above embodiment. The formed thin film was 4.7 μm on the front surface side of the substrate and 0 μm on the back surface side.

  The curvature was measured by irradiating the surface of the thin film with laser light and observing the position of the reflected light. In this example, the measurement was performed by measuring the degree of curvature of the substrate at a plurality of positions up to ± 10 mm around the center of the substrate (that is, at a measurement position of 0 mm).

In FIG. 7, the result of having measured the curvature of the board | substrate obtained by the method as described in an Example and a comparative example is shown. In the figure, the curve represented by the solid line represents the result of the example, and the curve represented by the broken line represents the result of the comparative example.
As shown in this figure, in the comparative example in which the thin film was formed only on one side of the substrate, a curvature of 40 μm or more was observed, whereas in the example in which the thin film was simultaneously formed on both sides, the degree of curvature was within a radius of 10 mm. Was 5 μm or less. That is, it can be seen that the degree of curvature of the substrate is greatly reduced when the thin film is formed on both sides simultaneously as compared with the case where the thin film is formed only on one side of the substrate.

  As described above, according to the thin film forming method and thin film forming apparatus of the present invention, a thin film having a stress that cancels the stress of the thin film formed on one surface of the substrate is formed on the back surface of the substrate. It is possible to reduce the disadvantage that the substrate is bent by the stress of the thin film.

It is the fragmentary sectional view which looked at the thin film formation apparatus in the present invention from the upper surface. It is the fragmentary sectional view which looked at the thin film formation apparatus of FIG. 1 from arrow A direction. It is the fragmentary sectional view which looked at the thin film formation apparatus of FIG. 1 from the arrow B direction. It is the fragmentary sectional view which looked at the thin film formation apparatus in other embodiments of the present invention from the upper surface. It is the fragmentary sectional view which looked at the thin film formation apparatus in other embodiments of the present invention from the upper surface. It is the fragmentary sectional view which looked at the thin film formation apparatus in other embodiments of the present invention from the side. It is a graph which shows the result of having measured the curvature of the board | substrate obtained by the method as described in an Example and a comparative example.

DESCRIPTION OF SYMBOLS 1 Thin film formation apparatus 11 Vacuum vessel 11 Vacuum vessel 11a Opening 11b Opening 11c Opening 11d Inlet / outlet 11e Opening 11f Opening 11i Opening 11j Opening 13 Substrate holder (base holder)
13a Holder 13b Bolt 14-1 Lower support member 14-1a Protrusion 14-1b Hydraulic cylinder 14-2 Lower support member 14-2a Protrusion 15a Piping 15b Piping 15c Piping 16 Door 17 Motor 17a Rotating shaft 18a Partition wall 18b Partition wall 18c Partition wall 18d Partition wall 18e Partition wall 18f Partition wall 20 Film formation process region (first film formation process region)
20A Sputtering means 21 Target 22 Magnetron sputtering electrode 23 Electrode installation plate 24 Transformer 25 AC power supply 26 Mass flow controller 27 Sputtering gas cylinder 28 Massflow controller 29 Reactive gas cylinder 30 Deposition process area (second deposition process area)
31 Target 32 Magnetron Sputtering Electrode 33 Electrode Installation Plate 34 Transformer 35 AC Power Supply 36 Mass Flow Controller 37 Sputtering Gas Cylinder 38 Massflow Controller 39 Reactive Gas Cylinder 40 Deposition Process Area (Third Deposition Process Area)
40A Sputtering means 41 Target 42 Magnetron sputter electrode 43 Electrode installation plate 44 AC power supply 45 Transformer 46 Mass flow controller 47 Sputter gas cylinder 48 Mass flow controller 49 Reactive gas cylinder 50 Deposition process area (fourth film formation process area)
50A Sputtering means 51 Target 52 Magnetron sputter electrode 53 Electrode installation plate 54 AC power supply 55 Transformer 56 Mass flow controller 57 Sputter gas cylinder 58 Mass flow controller 59 Reactive gas cylinder 60 Reaction process area (first reaction process area)
60A Plasma generating means 61 Antenna 62 Dielectric plate 63 Case body 64 Matching box 65 High frequency power supply 66 Mass flow controller 67 Inactive gas cylinder 68 Mass flow controller 69 Reactive gas cylinder 70 Reaction process area (second reaction process area)
70A Plasma generating means 71 Antenna 72 Dielectric plate 73 Case body 76 Mass flow controller 77 Inactive gas cylinder 78 Mass flow controller 79 Reactive gas cylinder 81 Shielding plate 82 Rotating shaft 83 Motor 91 Shielding plate 92 Rotating shaft 93 Motor S Substrate (base)
Z center axis

Claims (6)

Sputtering is performed on the target disposed in the film forming process area in the vacuum vessel to form an intermediate thin film on the substrate, and the intermediate thin film and the reactive gas are reacted in the reaction process area in the vacuum vessel. A thin film forming method using a sputtering apparatus for forming a thin film,
An intermediate thin film forming step of forming the intermediate thin film substantially simultaneously by sputtering on both sides of the substrate;
A reaction step of reacting a reactive gas with each of the intermediate thin films formed on both surfaces of the substrate to form the thin films substantially simultaneously;
Forming on one surface of the substrate a thin film that cancels out the curvature of the substrate by the thin film formed on the surface opposite to the substrate; and
A method of forming a thin film, characterized in that the film thickness of the thin film formed on the opposite surface of the substrate is determined based on the type and film thickness of the thin film formed on one surface of the substrate. Sputtering is performed on the target disposed in the film forming process area in the vacuum vessel to form an intermediate thin film on the substrate, and the intermediate thin film and the reactive gas are reacted in the reaction process area in the vacuum vessel. A thin film forming method using a sputtering apparatus for forming a thin film,
A first intermediate thin film forming step of forming the first intermediate thin film substantially simultaneously by sputtering on both sides of the substrate;
A second intermediate thin film forming step of forming the second intermediate thin film having a refractive index different from the refractive index of the first intermediate thin film by sputtering on both surfaces of the substrate, substantially simultaneously,
A reaction step of reacting a reactive gas with the first intermediate thin film and the second intermediate thin film formed on both sides of the substrate to form thin films substantially simultaneously;
Forming on one surface of the substrate a thin film that cancels out the curvature of the substrate by the thin film formed on the surface opposite to the substrate; and
A method of forming a thin film, characterized in that the film thickness of the thin film formed on the opposite surface of the substrate is determined based on the type and film thickness of the thin film formed on one surface of the substrate.   The film thickness is determined by setting the power supplied to each target installed in the film forming process area, setting the opening of a shielding plate that shields the film raw material supplied from the target toward the substrate, and each target. The thin film forming method according to claim 1, wherein: is set by determining at least one of a setting of a flow rate of a gas supplied to each film forming process region. Sputtering is performed on the target disposed in the film forming process area in the vacuum vessel to form an intermediate thin film on the substrate, and the intermediate thin film and the reactive gas are reacted in the reaction process area in the vacuum vessel. A thin film forming apparatus for forming a thin film,
A substrate holder installed in the vacuum vessel and holding the substrate;
A first film forming process region disposed on one side of the substrate holder and forming an intermediate thin film on one surface of the substrate;
A second film-forming process region disposed on the opposite side of the first film-forming process region across the substrate holder, and forming an intermediate thin film on the surface on the opposite side of the substrate;
A first reaction process region that is spatially separated from the first film formation process region and forms a thin film by reacting an intermediate thin film formed on one surface of the substrate with a reactive gas;
A second reaction that is disposed on the opposite side of the first reaction process region with the substrate holder in between, and forms a thin film by reacting an intermediate thin film formed on the opposite surface of the substrate with a reactive gas. A process area, and
In the second film formation process region and the second reaction process region, the thin film formed on the opposite surface has a thin film that cancels the curvature of the substrate due to the thin film formed on the one surface. The second film formation process region and the second reaction process region are controlled so as to be determined and formed based on the type and film thickness of the thin film formed on one surface of the substrate. A thin film forming apparatus. Sputtering is performed on the target disposed in the film forming process area in the vacuum vessel to form an intermediate thin film on the substrate, and the intermediate thin film and the reactive gas are reacted in the reaction process area in the vacuum vessel. A thin film forming apparatus for forming a thin film,
A substrate holder installed in the vacuum vessel and holding the substrate;
A first film forming process region disposed on one side of the substrate holder and forming an intermediate thin film on one surface of the substrate;
A second film-forming process region disposed on the opposite side of the first film-forming process region across the substrate holder, and forming an intermediate thin film on the surface on the opposite side of the substrate;
A third film formed in a region spatially separated from the first film forming process region and the second film forming process region and formed on the same side as the first film forming process region Process areas,
A fourth film forming process formed in a region spatially separated from the first to third film forming process regions and disposed on the opposite side of the third film forming process region with the substrate holder interposed therebetween. Area,
A first reaction process region which is spatially separated from the first to fourth film formation process regions and forms a thin film by reacting an intermediate thin film formed on one surface of the substrate with a reactive gas; ,
The substrate is spatially separated from the first to fourth film forming process regions and the first reaction process region, and is formed on the opposite side of the first reaction process region with the substrate holder interposed therebetween. A second reaction process region for forming a thin film by reacting an intermediate thin film formed on the opposite surface of the substrate with a reactive gas,
In the second film formation process region, the fourth film formation process region, and the second reaction process region, a thin film that cancels the curvature of the substrate due to the thin film formed on the one surface is disposed on the opposite surface. The second film forming process region and the fourth component are formed so that the thickness of the thin film formed on the first substrate is determined based on the type and thickness of the thin film formed on one surface of the substrate. A thin film forming apparatus for controlling a film process region and the second reaction process region. The film thickness of the thin film that cancels the curvature of the substrate is set by the power supply to each target installed in the film forming process region, and the shielding plate that shields the film raw material supplied from each target toward the substrate. 6. The thin film forming apparatus according to claim 4, wherein the thin film forming apparatus is set by determining at least one of an opening degree setting and a flow rate setting of a gas supplied to each film forming process region for each target. .

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