JP2018035425A - Film deposition method of dielectric film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition method of a dielectric film capable of suppressing increase of a film deposition time, while suppressing decline of a refractive index and lowering of a film deposition rate.SOLUTION: A film deposition method of a dielectric film includes: the first film deposition process for forming the first dielectric film having the first refractive index inside a chamber, by the first film deposition method containing a process for consuming residual water inside the chamber; and the second film deposition process for forming the second dielectric film having the second refractive index higher than the first refractive index on the upper surface of the first dielectric film continuously in vacuum to the first film deposition process inside the chamber, by the second film deposition method different from the first film deposition method.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for forming a dielectric film, and more particularly to a method for forming a dielectric multilayer film.

  In order to reduce weight and improve optical characteristics, a product is manufactured in which a metal film is formed on the surface of a resin substrate and the metal film is covered with a dielectric film. For example, a mirror or the like that reflects an image from a projector and projects it onto a projection surface has a structure in which a reflection-enhancing film is disposed so as to cover a metal film formed on a resin substrate. A structure in which a high-refractive index dielectric film and a low-refractive index dielectric film are alternately laminated is used for the increased reflection film. The reflective reflection film is generally formed by a vacuum film forming method such as a sputtering method or a vapor deposition method (see, for example, Patent Document 1).

  The dielectric film constituting the reflective film is easily affected by moisture remaining in the film forming apparatus (hereinafter referred to as “residual moisture”) and oxygen, and residual moisture and oxygen are taken into the dielectric film. As a result, the refractive index and deposition rate of the dielectric film are reduced. In particular, the influence is large in a dielectric film having a high refractive index. When the refractive index of the high refractive index dielectric film decreases, the difference in refractive index from the low refractive index dielectric film becomes small. It is necessary to increase the thickness. As a result, the film formation cost increases, such as an increase in the tact time of the film formation process and an increase in the amount of source gas used.

For this reason, in order to reduce the residual gas inside the film forming apparatus, a method of performing film formation after evacuating to 1 × 10 ⁻⁴ to 10 ⁻⁵ Pa is used.

Japanese Patent Application Laid-Open No. 07-281013

However, it takes time to evacuate to 1 × 10 ⁻⁴ to 10 ⁻⁵ Pa. In particular, when a resin substrate is used, moisture is released from a resin substrate that easily absorbs moisture, so that it takes longer to evacuate than when a silicon substrate or a glass substrate is used. With respect to the residual gas, water with a large adsorption coefficient remains in the film forming apparatus until the end, so that it takes several hours only by evacuation. For this reason, there has been a problem that the film formation time increases in the formation of a dielectric film having a high refractive index.

  In view of the above problems, an object of the present invention is to provide a method for forming a dielectric film in which an increase in film formation time is suppressed while a decrease in refractive index and a decrease in film formation speed are suppressed.

  According to one aspect of the present invention, a first dielectric film having a first refractive index is formed inside a chamber by a first film forming method including a process of consuming residual moisture inside the chamber. A second dielectric film having a second refractive index higher than the first refractive index is formed inside the chamber by the film formation process and a second film formation method different from the first film formation method. A dielectric film forming method including a film process and a second film forming process formed on the upper surface of the first dielectric film in a continuous vacuum is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the film-forming method of the dielectric film by which the increase in film-forming time was suppressed, suppressing the fall of a refractive index and the film-forming speed | rate can be provided.

It is a flowchart for demonstrating the film-forming method of the dielectric film which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the dielectric multilayer film formed by the film-forming method of the dielectric film which concerns on the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the film-forming method of the dielectric film which concerns on the 1st Embodiment of this invention (the 1). FIG. 6 is a schematic diagram for explaining the dielectric film forming method according to the first embodiment of the present invention (No. 2). It is a schematic diagram for demonstrating the film-forming method of the dielectric film which concerns on the 1st Embodiment of this invention (the 3). It is a schematic diagram for demonstrating pre-sputtering in the film-forming method of the dielectric film which concerns on the 1st Embodiment of this invention. It is a flowchart for demonstrating the film-forming method of the dielectric film which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows the structure of the dielectric multilayer film formed by the film-forming method of the dielectric film concerning the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiments shown below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the embodiments of the present invention are materials, shapes, structures, arrangements, etc. of components. Is not specified as follows. The embodiment of the present invention can be variously modified within the scope of the claims.

(First embodiment)
As shown in FIG. 1, the dielectric film forming method according to the first embodiment of the present invention uses the first film forming method including the process of consuming residual moisture inside the chamber to perform the first refraction. The second refraction higher than the first refractive index by the first film formation process (step S1) for forming the first dielectric film having the refractive index and the second film formation method different from the first film formation method A second film formation process (step S2) for forming a second dielectric film with a rate on the upper surface of the first dielectric film. The first dielectric film and the second dielectric film are continuously formed in a vacuum inside the chamber.

  Furthermore, the method for forming a dielectric film shown in FIG. 1 further includes a third film forming process (step S3) for forming a third dielectric film on the upper surface of the second dielectric film. The third film forming process is performed continuously with the second film forming process in a vacuum. The third dielectric film is formed by, for example, a first film formation method.

  FIG. 2 shows an example of the dielectric multilayer film 10 formed by the film forming method shown in FIG. The third dielectric film 13 functions as a protective film, such as preventing oxidation of the second dielectric film 12.

  For the first film formation method, for example, a plasma CVD method is preferably used. In the plasma CVD method, since the residual moisture is turned into plasma, the dielectric film being deposited and the residual moisture are easily bonded. That is, residual moisture is taken into the first dielectric film 11 during film formation, and moisture inside the chamber is removed. Thus, in the plasma CVD method, much residual moisture inside the chamber is consumed during film formation.

  As the second film forming method, a film forming method capable of forming a dielectric film having a high refractive index is used. For example, a sputtering method, a vacuum deposition method, or the like can be selected as the second film formation method. However, in the vacuum deposition method, it is necessary to make the inside of the chamber a high vacuum, which may increase the tact time. For this reason, the sputtering method is more preferable. Note that titanium oxide, niobium oxide, tantalum oxide, and the like can be considered as the dielectric film having a high refractive index. However, there is a safety problem in forming these dielectric films by the CVD method. For this reason, the sputtering method is preferably used as the second film forming method. The second film forming method need not include a process of consuming residual moisture.

  Hereinafter, a case where the plasma CVD method is used for the first film formation process and a sputtering method that can form a dielectric film having a higher refractive index than that of the plasma CVD method is used for the second film formation process. explain. That is, the dielectric multilayer film 10 shown in FIG. 2 is formed by the first dielectric film 11 formed by the plasma CVD method, the second dielectric film 12 formed by the sputtering method, and the plasma CVD method. The third dielectric film 13 is formed by laminating in this order.

  The refractive index of the second dielectric film 12 is higher than the refractive index of the first dielectric film 11, and the refractive index of the first dielectric film 11 and the refractive index of the third dielectric film 13 are equal. For example, the first dielectric film 11 and the third dielectric film 13 have a refractive index with respect to incident light having a wavelength of 550 nm (hereinafter simply referred to as “refractive index”) of about 1.4 to 1.5. It is. The first dielectric film 11 is a dielectric film having a refractive index of about 2.2 to 2.3.

  As shown in FIG. 2, the dielectric multilayer film 10 is formed on the base 20 having the metal film 22 formed on the resin substrate 21 so as to cover the metal film 22. For example, a polycarbonate material or an acrylic material can be used for the resin substrate 21. The metal film 22 is, for example, an aluminum (Al) film. By disposing the metal film 22 on the surface of the resin substrate 21, a lightweight product can be provided. The dielectric multilayer film 10 functions as an increased reflection film of this product.

  The dielectric multilayer film 10 is formed using, for example, a film forming apparatus shown in FIG. The film forming apparatus shown in FIG. 3 includes a chamber 100 in which a first processing region 101 and a second processing region 102 in which film forming processes are respectively performed are prepared. As will be described later, a first film formation process by a plasma CVD method is performed in the first processing region 101, and a second film formation process by a sputtering method is performed in the second processing region 102.

  According to the film forming apparatus having the chamber 100 in which two processing regions are prepared, the film forming processing in each processing region can be performed continuously in vacuum without opening the inside of the chamber 100 to the atmosphere. Hereinafter, a method of forming the dielectric multilayer film 10 using the film forming apparatus shown in FIG. 3 will be described.

  A base 20 having a metal film 22 formed on a resin substrate 21 is prepared. Next, the base body 20 mounted on the sample holder 200 is stored in the chamber 100. Inside the chamber 100, the sample holder 200 on which the substrate 20 is mounted is transported between the first processing region 101 and the second processing region 102 by the transport device 130. First, as shown in FIG. 3, the substrate 20 is disposed in the first processing region 101.

  After the inside of the chamber 100 is evacuated to an ultimate pressure of about 0.1 to 1 Pa, for example, 0.5 Pa, the first dielectric film 11 is formed so as to cover the metal film 22 by plasma CVD. This film forming process corresponds to step S1 in FIG. Since the ultimate pressure at the start of film formation is high, the time required for evacuating the inside of the chamber 100 can be shortened to several tens of seconds. Generally, the higher the ultimate pressure, the more residual moisture. However, by adopting the plasma CVD method, residual moisture is consumed in the first film forming process.

  In the first film formation process by the plasma CVD method in the first process region 101, a process gas 110 containing a raw material gas for a film to be formed on the substrate 20 is introduced into the chamber 100 by the first gas supply device 113. The In the first processing region 101, a cathode electrode 112 facing the substrate 20 is disposed. The sample holder 200 functions as an anode electrode, and predetermined AC power is supplied between the sample holder 200 and the cathode electrode 112 by the AC power source 111. Thereby, the process gas 110 containing the source gas in the chamber 100 is turned into plasma. By exposing the substrate 20 to the formed plasma, the first dielectric film 11 is formed on the surface of the substrate 20. At this time, the residual moisture inside the chamber 100 is consumed by bonding with the first dielectric film 11 being formed, and the residual moisture is removed from the inside of the chamber 100. Thereafter, the process gas 110 is exhausted from the inside of the chamber 100 by the exhaust device 140.

As the first dielectric film 11 having a low refractive index, for example, a SiOC film having a refractive index of 1.4 to 1.5 is formed with a film thickness of 60 nm to 80 nm. The SiOC film can be formed by converting a source gas containing hexamethyldisiloxane (HMDSO: O [Si (CH ₃ ) ₃ ] ₂ ) gas into plasma.

  Next, the sample holder 200 on which the substrate 20 is mounted is transported from the first processing region 101 by the transport device 130 and is disposed in the second processing region 102 as shown in FIG. In the second processing region 102, the second dielectric film 12 is formed by sputtering. This film forming process corresponds to step S2 in FIG.

  In the second processing region 102, the target 123 is attached on the target electrode 122. The target electrode 122 is connected to a sputtering power source 121 that supplies radio frequency (RF) power or direct current (DC) power. An inert gas 120 such as argon (Ar) gas is introduced into the chamber 100 from the second gas supply device 124. Electric power is supplied from the sputtering power source 121 to the target electrode 122 to cause discharge, and plasma is formed in the gas phase near the surface of the target 123. Positive ions of the inert gas 120 accelerated in the plasma collide with the surface of the target 123, and target atoms are released by sputtering. Atoms emitted from the surface of the target 123 are deposited and deposited on the upper surface of the first dielectric film 11 formed on the substrate 20. As a result, the second dielectric film 12 is formed on the upper surface of the first dielectric film 11. Thereafter, the inert gas 120 is exhausted from the inside of the chamber 100 by the exhaust device 140.

  For the formation of the second dielectric film 12 having a high refractive index, a DC magnetron sputtering method using a conductive oxide target is preferably used. For example, a titanium oxide (TiOx) material is used for the target 123, and a TiOx film having a refractive index of 2.2 to 2.3 is formed with a film thickness of 30 nm to 50 nm.

  Next, the sample holder 200 on which the substrate 20 is mounted is transported from the second processing region 102 by the transporting device 130 and placed in the first processing region 101 as shown in FIG. Similar to the formation of the first dielectric film 11, the third dielectric film 13 is formed on the upper surface of the second dielectric film 12 by plasma CVD. This film forming process corresponds to step S3 in FIG. For example, as the third dielectric film 13, a SiOC film having a refractive index of 1.4 to 1.5 and a thickness of about 10 nm is formed. Thus, the dielectric multilayer film 10 shown in FIG. 2 is formed.

  Note that it is preferable to perform pre-sputtering to form plasma in the gas phase near the surface of the target 123 immediately before forming the second dielectric film 12. For example, pre-sputtering is performed in the process of gradually increasing the power supplied to the target electrode 122 to a predetermined power that generates a discharge for forming the second dielectric film 12. Thereby, the surface oxide layer of the target 123 is removed. For example, pre-sputtering is performed before the sample holder 200 is transferred from the first processing region 101 to the second processing region 102 as shown in FIG.

  In the film forming method described above, the second film forming process by the sputtering method is performed after the first film forming process by the plasma CVD method. That is, before the step of forming the second dielectric film 12 having a high refractive index, the residual moisture is consumed in the step of forming the first dielectric film 11 having a low refractive index. Therefore, a second dielectric film having a high refractive index can be formed inside the chamber 100 from which residual moisture has been removed.

  Note that the refractive index of the first dielectric film 11 decreases due to the bonding of residual moisture. For this reason, the difference in refractive index between the first dielectric film 11 and the second dielectric film 12 can be increased.

  Usually, in a film forming process, deposits adhere to a stage on which a film forming target is placed inside a film forming apparatus and an electrode used for the film forming process. For example, in the film forming apparatus shown in FIG. 3 that does not include a load lock chamber, the interior of the chamber 100 is opened to the atmosphere for replacement of the substrate 20 after the film forming process. At this time, the deposit adhering to the inside of the chamber 100 absorbs moisture, and this becomes a supply source of residual moisture.

  However, in the film forming method described above, the first film forming process for forming the first dielectric film 11 is performed before the second film forming process for forming the second dielectric film 12 having a high refractive index. , The moisture absorbed by the deposits attached to the stage and the electrode is consumed, and the residual moisture inside is removed. For this reason, it is suppressed that the 2nd dielectric film 12 couple | bonds with a residual water | moisture content in the period of a 2nd film-forming process. Therefore, the refractive index of the second dielectric film 12 does not decrease. For this reason, it is not necessary to increase the film thickness of the second dielectric film 12 from the viewpoint of optical design, and the tact time and the amount of the source gas used do not increase. As a result, an increase in film formation cost can be suppressed.

  On the other hand, when the residual moisture is not consumed, the moisture absorbed by the deposit increases with an increase in the deposit due to the film forming process. In the film forming apparatus having the load lock chamber, the moisture released from the resin substrate becomes the residual moisture, and the refractive index of the second dielectric film 12 is lowered.

  A measure to suppress the bond between the dielectric film and the residual moisture by increasing the deposition rate can be considered. However, even with a DC magnetron sputtering method using a conductive oxide target in which a dielectric film having a high refractive index is formed at a relatively high film formation rate, the film formation rate is about 1 nm / second. This film formation rate is insufficient to suppress the bond between the dielectric film and residual moisture.

  For example, in the case of a comparative example in which both the first dielectric film 11 and the second dielectric film 12 are formed by sputtering, residual moisture is not consumed before the second dielectric film 12 is formed. Furthermore, the film formation rate of the second dielectric film 12 is not so high as to suppress the bond between the dielectric film and residual moisture. For this reason, the problem that the refractive index of the 2nd dielectric film 12 falls arises. In the comparative example in which residual moisture is not consumed before the formation of the second dielectric film 12, the refractive index of the second dielectric film 12 is as low as about 2.0 to 2.1. On the other hand, when the second dielectric film 12 is formed by a film forming method that lowers the ultimate pressure, the time required for evacuation increases and the tact time increases.

  As described above, in the film forming method according to the first embodiment of the present invention, the first dielectric film 11 having a low refractive index is formed by the first film forming method that consumes the residual moisture, and the residual moisture. Then, the second dielectric film 12 having a high refractive index is continuously formed in vacuum by the second film forming method. Thereby, it is suppressed that the 2nd dielectric film 12 couple | bonds with a residual water | moisture content. For this reason, it is possible to suppress a decrease in the refractive index and a decrease in the deposition rate of the second dielectric film 12 having a high refractive index. As a result, it is not necessary to form the second dielectric film 12 thick in order to compensate for the lowering of the refractive index, and it is possible to realize a film forming process in which an increase in tact time and an increase in cost are suppressed. Further, the ultimate pressure inside the chamber 100 at the start of film formation in the first film formation process is as high as about 0.1 to 1 Pa, and the time required for evacuation is short. For this reason, an increase in film formation time is suppressed.

  Further, as shown in FIG. 3 and the like, the first film formation process and the second process in the first process region 101 are performed by using the film formation apparatus having the chamber 100 in which two process regions are prepared. The second film formation process in the region 102 can be performed continuously in a vacuum. For this reason, the inside of the chamber 100 is not opened to the atmosphere during a series of steps for forming the dielectric multilayer film 10. That is, the inside of the chamber 100 is not exposed to the atmosphere containing moisture during the film forming process. Therefore, it is possible to prevent deposits and dielectric films adhering to the inside of the chamber 100 from becoming a source of residual moisture due to moisture absorption.

  The film forming method described above is particularly effective in the case of a film forming apparatus that does not include a load lock chamber and in which the inside of the chamber is exposed to the atmosphere each time the substrate 20 is replaced. According to the film forming apparatus that does not use the load lock chamber, the base 20 can be replaced in a short time, so that the tact time can be shortened. Further, by not providing the load lock chamber, the manufacturing cost of the film forming apparatus can be reduced.

  By the way, when the sputtering method is used for the second film forming method, there is a possibility that a problem such as oxidation of the surface of the target 123 may occur when the inside of the chamber 100 is opened to the atmosphere in order to replace the substrate 20. In particular, when the inside of the chamber 100 is opened to the atmosphere immediately after performing the second film formation process, the surface of the target 123 is likely to react, and thus is easily oxidized. For this reason, it is preferable that the film forming process immediately before the inside of the chamber 100 is opened to the atmosphere is not the film forming process by the sputtering method but the film forming process in the first processing region 101. For example, after the third film forming process for forming the third dielectric film 13 is performed, the inside of the chamber 100 is opened to the atmosphere. Further, in the third film forming process, by covering the surface of the target 123 with the material constituting the third dielectric film 13, it is possible to suppress oxidation on the surface of the target 123 in the atmosphere. Note that the substance coated on the surface of the target 123 can be removed by the pre-sputtering described above.

(Second Embodiment)
In the above, the example in which the dielectric multilayer film 10 having the three-layer structure in which the first dielectric film 11, the second dielectric film 12, and the third dielectric film 13 are stacked is shown. However, the number of dielectric multilayer films 10 is not limited to three, and the present invention can also be applied to the formation of four or more dielectric multilayer films 10. That is, the dielectric multilayer film 10 may be formed by using a combination of performing the second film forming process after the first film forming process as a unit process and repeating the unit process a plurality of times in a vacuum.

  In this unit process, before the dielectric film having a high refractive index is formed by the sputtering method, for example, in the second film forming process, the low refractive index is formed by the plasma CVD method, for example, in the first film forming process that consumes residual moisture. A dielectric film is formed. Therefore, by repeating the unit process in a continuous vacuum without exposing the dielectric multilayer film 10 being formed to the atmosphere, a decrease in the refractive index and a decrease in the deposition rate of the high refractive index dielectric film are suppressed. The As described above, the dielectric multilayer film 10 in which the high-refractive index dielectric films and the low-refractive index dielectric films are alternately stacked can be formed by the deposition flow in which the unit process is repeated.

  For example, it is possible to form a dielectric multilayer film 10 having four or more layers in which the first dielectric film 11 and the second dielectric film 12 are alternately laminated. FIG. 7 shows a flowchart in the case of forming the dielectric multilayer film 10 in which the first dielectric film 11 and the second dielectric film 12 are alternately laminated by repeating the unit process. The unit process including step S11 for forming the first dielectric film 11 and step S12 for forming the second dielectric film 12 is repeated until it is determined in step S13 that the desired dielectric multilayer film 10 has been formed. For example, the unit process is repeated until a predetermined film thickness is reached or until the first dielectric film 11 and the second dielectric film 12 have a predetermined number of layers.

  FIG. 8 shows a configuration example of the dielectric multilayer film 10 in which the first dielectric film 11 and the second dielectric film 12 are alternately stacked. Thereafter, if necessary, a third dielectric film 13 is formed on the second dielectric film 12 as the uppermost layer of the dielectric multilayer film 10 shown in FIG.

  According to the above film forming method, even when the dielectric multilayer film 10 including a plurality of high refractive index dielectric films is formed, the refractive index of the high refractive index dielectric film is decreased and the film formation speed is reduced. The decrease can be suppressed. Others are substantially the same as those in the first embodiment, and redundant description is omitted.

(Other embodiments)
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above description, the case where the first dielectric film 11 having the low refractive index is formed by the plasma CVD method and the second dielectric film 12 having the high refractive index is formed by the sputtering method has been described. However, after the residual moisture is consumed in the process of forming the first dielectric film 11, if the residual moisture is not generated during the formation of the dielectric multilayer film 10, any subsequent dielectric film is optional. The film forming method can be employed. For example, if each layer of the dielectric multilayer film 10 is formed in vacuum continuously without opening the inside of the chamber 100 to the atmosphere during the formation of the dielectric multilayer film 10, low refraction after the third dielectric film 13 is achieved. Sputtering may also be employed for the dielectric film having a high rate. However, from the viewpoint of the configuration of the film forming apparatus, another low refractive index dielectric film is formed by the same film forming method as the first dielectric film 11, and the other film forming method is the same as the second dielectric film 12. It is preferable to form a high refractive index dielectric film.

  Moreover, although the case where the dielectric multilayer film 10 is formed by the film forming apparatus having the chamber 100 in which a plurality of processing regions are prepared is exemplified, the film forming apparatus having another configuration may be used. Of course. For example, the present invention can be applied to the case where the dielectric multilayer film 10 is formed by a film forming apparatus having a plurality of chambers.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 10 ... Dielectric multilayer film 11 ... 1st dielectric film 12 ... 2nd dielectric film 13 ... 3rd dielectric film 20 ... Base | substrate 21 ... Resin substrate 22 ... Metal film

Claims (10)

A first film-forming process for forming a first dielectric film having a first refractive index inside the chamber by a first film-forming method including a process of consuming residual moisture inside the chamber;
A second dielectric film having a second refractive index higher than the first refractive index is formed inside the chamber by a second film formation method different from the first film formation method. And a second film forming process formed on the upper surface of the first dielectric film in a continuous vacuum.   2. The dielectric film forming method according to claim 1, wherein in the first film forming method, the residual moisture is taken into the first dielectric film during film formation.   3. The dielectric film forming method according to claim 1, wherein the first film forming method is a plasma CVD method.   4. The dielectric film forming method according to claim 1, wherein the second film forming method is a sputtering method. 5.   The pre-sputtering for forming plasma in the gas phase in the vicinity of the surface of the target used in the second film-forming method is performed immediately before forming the second dielectric film. A method for forming a dielectric film.   6. The method according to claim 1, further comprising a third film forming process for forming a third dielectric film on the upper surface of the second dielectric film in a continuous vacuum with the second film forming process. 2. A method for forming a dielectric film according to item 1. The second film forming method is a sputtering method,
7. The dielectric according to claim 6, wherein in the third film forming process, a surface of a target used in the second film forming method is covered with a material constituting the third dielectric film. Method for forming body film.   A combination of performing the second film forming process after the first film forming process is used as a unit process, and the unit process is repeated a plurality of times in a vacuum, whereby the first dielectric film and the second dielectric film 8. The method of forming a dielectric film according to claim 1, wherein a dielectric multilayer film is formed by alternately laminating layers.   The dielectric film according to any one of claims 1 to 8, wherein an ultimate pressure inside the chamber at the start of film formation in the first film formation process is 0.1 to 1 Pa. Film forming method.   10. The method for forming a dielectric film according to claim 1, wherein the first dielectric film is formed so as to cover a metal film formed on the resin substrate.

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