JP7656466B2 - Film forming apparatus and film forming method - Google Patents

Description

The present invention relates to a film forming apparatus and a film forming method.

In the manufacturing process of various products such as semiconductor devices, liquid crystal displays, organic electroluminescence displays, and optical disks, thin films such as optical films may be created on workpieces such as wafers and glass substrates. Thin films can be created by performing a film formation process in which a metal film or other film is formed on the workpiece, or by performing film treatments such as etching, oxidation, or nitridation on the formed film.

Film formation or film processing can be performed in various ways, one of which is to generate plasma in a chamber decompressed to a specified degree of vacuum and use that plasma to perform processing. In film formation, an inert gas is introduced into a chamber in which a target made of film formation material is placed, and a direct current voltage is applied to the target. Ions of the inert gas that has been made into a plasma are collided with the target, and the film formation material that is knocked out of the target is deposited on the workpiece to form a film. This type of film formation process is called sputtering. In film processing, a process gas is introduced into a vacuum chamber in which an electrode is placed, and a high-frequency voltage is applied to the electrode. Active species such as ions and radicals from the process gas that has been made into a plasma are collided with the film on the workpiece.

In order to perform such film formation and film processing consecutively, there is a film formation device in which a rotating table, which is a rotating body, is installed inside one chamber, and multiple film formation processing sections and film processing sections are arranged in the circumferential direction above the rotating table. The film formation processing sections and film processing sections are each arranged in separate compartments within the chamber, and a workpiece held on the rotating table passes directly under the film formation processing section and film processing section, forming a thin film such as an optical film on the workpiece.

As the film formation process continues, film formation material scattered from the film formation unit accumulates in various locations within the chamber of the film formation device as described above. If the accumulated film formation material peels off, the workpiece on which the film is to be formed will be contaminated. However, if a film adheres directly to the inner wall of the chamber or the rotating table, it is very difficult to remove. For this reason, a removable anti-adhesion plate is provided to cover the inner wall of the chamber, the surface of the rotating table, etc. The anti-adhesion plate prevents the film formation material scattered during the film formation process from adhering to the inner wall of the chamber or the surface of the rotating table.

After continuous film formation, such adhesion prevention plates must be removed and cleaned (for maintenance) to prevent the attached film from peeling off and contaminating the workpiece. For example, the chamber is opened to the atmosphere, the adhesion prevention plate is removed from the chamber, the film deposited on the surface is removed by sandblasting, and then it is washed with pure water. After cleaning and drying, it is transported to the film formation device in a vacuum-packed state, unpacked, and reattached to the film formation device for film formation. When the adhesion prevention plate is attached after cleaning and drying, moisture remains inside the adhesion prevention plate, and as the pressure inside the chamber is reduced, a large amount of moisture continues to be generated from the adhesion prevention plate.

In addition to the above, moisture can enter the chamber for various reasons. For example, when the chamber is opened to the atmosphere for maintenance, the moisture in the air is adsorbed onto the walls and various components inside the chamber. Moisture may also adhere to items brought into the chamber, such as the workpieces or the trays that hold the workpieces.

As the pressure inside the chamber is reduced, the moisture gradually evaporates and is exhausted, so this condition improves as film formation continues. However, the number and area of the components that contain moisture, including the adhesion prevention plates installed inside the chamber, are very large, so the amount of moisture generated also increases. For this reason, it is difficult to completely remove the moisture in a short period of time and obtain the degree of vacuum required for processing. For example, it may take several days to several weeks to reach a favorable state for film formation. As a result, after the chamber is opened to the atmosphere for maintenance or after the adhesion prevention plates are replaced, film formation cannot be performed for a long period of time, reducing productivity.

To address this issue, methods have been proposed, such as providing a heating device such as an infrared lamp inside the chamber (Patent Document 1) and introducing heated gas to heat the components inside the chamber and promote evaporation of moisture (Patent Document 2).

JP 2005-352018 A JP 2010-225847 A

The manufacturing process of electronic devices includes a process using a plasma processing apparatus using plasma or highly corrosive fluorine-based gas, such as dry etching. In order to protect the inside of a chamber in which electronic devices are manufactured from damage caused by plasma and corrosion caused by fluorine-based gas, a method is used in which a film of yttrium oxide (Y ₂ O ₃ ), also known as yttria, is formed on members of the plasma processing apparatus, such as the chamber inner wall and electrodes.

In order to coat components of a plasma processing apparatus with an yttria film, it is being considered to use a film-forming apparatus in which a target containing yttrium is placed. That is, it is being considered to form an yttrium film on the surface of the component by forming an yttrium film on the component of the plasma processing apparatus by sputtering, and then colliding oxygen atoms with the yttrium film on the component to oxidize it.

When forming a film by sputtering, the atmosphere in the chamber of the film forming apparatus is depressurized to a high vacuum range. This reduces the impurities present in the chamber and reduces the number of gas molecules so that the mean free path is large. As a result, the film forming material that is knocked out from the target reaches the workpiece, resulting in a stable and dense film. However, if moisture remains in the chamber of the film forming apparatus, the degree of vacuum in the chamber will not increase, and there is a risk that a dense film will not be obtained. This may result in a deterioration of the corrosion resistance required for a coating film on components of a plasma processing apparatus.

The method of providing a heating device in Patent Document 1 and the method of introducing heated gas in Patent Document 2 require providing a heating device for each of the multiple processing chambers in the film formation apparatus and introducing heated inert gas, which complicates the apparatus configuration and increases costs, making them unrealistic.

The present invention has been proposed to solve the problems described above, and aims to provide a film formation apparatus and a film formation method that can promote the removal of moisture from within a chamber without complicating the apparatus.

In order to achieve the above object, the film forming apparatus of this embodiment includes a chamber capable of evacuating the inside thereof, a rotating table provided in the chamber, which holds a workpiece and circulates and transports the workpiece along a circular trajectory, a target made of a film forming material containing yttrium, a plasma generator which applies a voltage to the target and converts a sputtering gas introduced between the target and the rotating table into plasma, and a film forming processing section which knocks out yttrium particles from the target toward the rotating table and deposits an yttrium film on the workpiece held on the rotating table, an oxygen gas introduction section which introduces oxygen gas, and a film processing section which has a plasma generator which converts the oxygen gas into plasma and oxidizes the yttrium film deposited on the workpiece, and a control section which controls the operation of the rotating table, the film forming processing section, and the film processing section, and the control section rotates the rotating table in a state in which the workpiece is not held, applies a voltage to the target, and knocks out yttrium particles toward the rotating table on which the workpiece is not held.

The film forming method of the present invention is a film forming method using a film forming apparatus including a chamber capable of evacuating the inside, a rotating table provided in the chamber, holding a workpiece and circulating and transporting the workpiece along a circular trajectory, a target made of a film forming material containing yttrium, a plasma generator that applies a voltage to the target and turns a sputtering gas introduced between the target and the rotating table into plasma, and a film forming processing section that knocks out yttrium particles from the target toward the workpiece being circulated and transported by the rotating table to form an yttrium film on the workpiece, an oxygen gas introduction section that introduces oxygen gas, and a film processing section that has a plasma generator that turns the oxygen gas into plasma and oxidizes the formed yttrium film, characterized in that the rotating table is rotated while the workpiece is not held, a voltage is applied to the target, and yttrium particles are knocked out toward the rotating table not holding the workpiece.

The present invention provides a film formation apparatus and a film formation method that can promote the removal of moisture from within a chamber without complicating the apparatus.

1 is a perspective plan view showing a schematic configuration of a film forming apparatus according to an embodiment of the present invention; 2 is a cross-sectional view taken along the line AA in FIG. 1, showing in detail the internal configuration of the film forming apparatus according to the embodiment of FIG. 1 as viewed from the side. FIG. 2 is a plan view showing a tray during production of a getter material. 1 is a flowchart of a film forming operation for producing a getter material.

Embodiments of the film forming apparatus and film forming method according to the present invention will be described in detail with reference to the drawings. In each drawing, thickness, dimensions, positional relationships, ratios, shapes, etc. may be emphasized to facilitate understanding, but the present invention is not limited to such emphasis.

(composition)
As shown in the perspective plan view of the film forming apparatus 1 in Fig. 1 and the cross-sectional view in Fig. 2, the film forming apparatus 1 is an apparatus for forming an yttria film on a workpiece W by sputtering. The workpiece W refers to a processing object whose surface is protected by an yttria film because it is exposed to plasma or corrosive gas such as a fluorine-based gas, and examples of such objects include the inner wall of a chamber in which dry etching of an electronic device is performed. However, the workpiece W can be any object on which an yttria film is to be formed, regardless of its shape or material.

This film formation apparatus 1 has a chamber 10, a rotating table 30, a film formation processing section 40, a film processing section 50, a transfer chamber 70, and a control section 80. In addition, an exhaust section 20 is connected to the chamber 10, a tray 60 is detachably installed on the rotating table 30, and a load lock section 71 is connected to the transfer chamber 70.

The chamber 10 is a cylindrical container whose interior can be evacuated, and is formed by a disk-shaped ceiling 10a, a disk-shaped inner bottom surface 10b, and an annular inner peripheral surface 10c. An exhaust unit 20 is connected to the chamber 10. The exhaust unit 20 has piping and a pump, valves, etc. (not shown). By exhausting through the exhaust unit 20, the pressure inside the chamber 10 is reduced to create a vacuum.

The rotating table 30 is a transport means that places the workpiece W on its upper surface and transports it around along a circular trajectory L, and is disposed in a cylindrical space secured in the inner bottom surface 10b of the chamber 10. The rotating table 30 has a disk shape that extends concentrically with the chamber 10, and extends widely inside the chamber 10 so as not to come into contact with the inner peripheral surface 10c. The rotating table 30 is supported by a motor 31 and rotates continuously at a predetermined rotational speed with the center of the circle of the rotating table 30 as the rotation axis.

The rotating table 30 is made of metal, and may be, for example, a stainless steel plate member with aluminum oxide sprayed on its surface. A plurality of holding portions 32 are arranged at equal circumferential positions on the upper surface of the rotating table 30. The holding portions 32 are grooves, holes, protrusions, jigs, holders, etc., and hold the trays 60 carrying the workpieces W by a mechanical chuck, adhesive chuck, etc. For example, six trays 60 are arranged at 60° intervals on the rotating table 30. However, the number of workpieces W and trays 60 transported simultaneously is not limited to this. The trays 60 carrying the workpieces W are brought in from the transfer chamber 70 and placed on the rotating table 30.

The transfer chamber 70 is a passageway in which the tray 60 holding the workpiece W is accommodated before being transported into the chamber 10. The transfer chamber 70 is connected to the chamber 10 via a gate valve GV1. A transport means (not shown) is provided in the internal space of the transfer chamber 70 for transporting the workpiece W to and from the chamber 10. The transfer chamber 70 is depressurized by exhaust from a vacuum pump (not shown), and while the vacuum of the chamber 10 is maintained by the transport means, the tray 60 carrying the unprocessed workpiece W is transported into the chamber 10, and the tray 60 carrying the processed workpiece W is transported out of the chamber 10.

The load lock unit 71 is connected to the transfer chamber 70 via a gate valve GV2. The load lock unit 71 is a device that transports a tray 60 carrying unprocessed workpieces W from the outside into the transfer chamber 70 by a transport means (not shown) while maintaining the vacuum in the transfer chamber 70, and transports the tray 60 carrying processed workpieces W out of the transfer chamber 70. The load lock unit 71 is depressurized by exhaust from a vacuum pump (not shown). The workpieces W placed on the turntable 30 from the transfer chamber 70 pass through the film forming processing unit 40 and the film processing unit 50 along a circular trajectory L as the turntable 30 rotates.

The film forming processing units 40 are arranged at three locations along the circular locus L. Each film forming processing unit 40 generates plasma and exposes the target 412 to the plasma. As a result, the film forming processing unit 40 causes ions contained in the plasma to collide with the target 412, and deposits particles knocked out of the target 412 on the workpiece W to form a film. This film forming processing unit 40 includes a sputtering source consisting of the target 412, a backing plate 413, and an electrode 414, and a plasma generator consisting of a power supply unit 416 and a sputtering gas introduction unit 419.

The target 412 is a plate-shaped member made of a film-forming material containing yttrium. The targets 412 are provided at a distance from each other on the circular trajectory L along which the workpiece W is transported. The surface of the target 412 is held by the ceiling 10a of the chamber 10 so as to face the workpiece W placed on the rotating table 30. Three targets 412 are provided at positions aligned on the vertices of a triangle in a plan view.

The backing plate 413 is a support member that holds the targets 412. This backing plate 413 holds each target 412 individually. The electrode 414 is a conductive member for applying power to each target 412 individually from outside the chamber 10, and is electrically connected to the targets 412. The power applied to each target 412 can be changed individually. In addition, the sputtering source is appropriately equipped with magnets, cooling mechanisms, etc. as necessary.

The power supply unit 416 is, for example, a DC power supply that applies a high voltage, and is electrically connected to the electrode 414. The power supply unit 416 applies a voltage to the target 412 through the electrode 414. The rotating table 30 is at the same potential as the grounded chamber 10, and a potential difference is generated by applying a high voltage to the target 412 side. The power supply unit 416 can also be an RF power supply to perform high-frequency sputtering.

The sputtering gas introduction section 419 introduces the sputtering gas G1 into the chamber 10. The sputtering gas introduction section 419 has a supply source of the sputtering gas G1 such as a cylinder (not shown), a pipe 418, and a gas introduction port 417. The pipe 418 is connected to the supply source of the sputtering gas G1, airtightly penetrates the chamber 10, extends into the interior of the chamber 10, and opens at its end as the gas introduction port 417. The gas introduction port 417 opens between the turntable 30 and the target 412, and introduces the sputtering gas G1 for film formation into the processing space 41 formed between the turntable 30 and the target 412. A rare gas can be used as the sputtering gas G1, and argon (Ar) gas or the like is preferable.

In this type of film forming processing section 40, sputtering gas G1 is introduced from the sputtering gas inlet 419, and the power supply section 416 applies a high voltage to the target 412 through the electrode 414. Then, the sputtering gas G1 introduced into the processing space 41 is turned into plasma, and active species such as ions are generated. The ions in the plasma collide with the target 412 and knock out yttrium particles of the film forming material. The yttrium particles knocked out from the target 412 are deposited on the workpiece W when the workpiece W passes directly under the film forming processing section 40 as the turntable 30 rotates. As a result, a film made of yttrium particles is formed on the workpiece W. The workpiece W is circulated and transported by the turntable 30, and the film forming process is performed by repeatedly passing through the film forming processing section 40.

The processing space 41 of each film forming processing unit 40 is surrounded by a box-type shielding member 11 with holes for the target 412, and the box-type shielding member 11 prevents the film forming material and the sputtering gas G1 from diffusing into the chamber 10. The box-type shielding member 11 is an annular sector box with a ceiling made of a plate-shaped annular sector arranged parallel to the plane of the rotary table 30, and is defined by an outer peripheral wall extending from the outer peripheral arc of the annular sector ceiling toward the rotary table 30, an inner peripheral wall extending from the inner peripheral arc of the annular sector ceiling, and a side wall extending from the side along the radius of the annular sector ceiling, and the surface facing the rotary table 30 opposite the ceiling is open. Between the lower end of the box-type shielding member 11 and the rotary table 30, a gap is formed that allows the workpiece W placed on the rotary table 30 to pass through.

The film processing section 50 is assigned to one location on the circular locus L. This film processing section 50 has a plasma generator composed of a cylindrical body 51, a window member 52, an antenna 53, an RF power source 54, a matching box 55, and an oxygen gas introduction section 56.

The cylindrical body 51 is a member that covers the periphery of the processing space 59, which is the space where the membrane processing is performed. As shown in Figures 1 and 2, the cylindrical body 51 is a cylinder with a rounded rectangular cross section and has an opening. The cylindrical body 51 is fitted into the ceiling 10a of the chamber 10 so that its opening faces away from the turntable 30 and protrudes into the internal space of the chamber 10. The cylindrical body 51 is made of metal, similar to the turntable 30. The processing space 59 is formed between the turntable 30 and the inside of the cylindrical body 51. The workpieces W, which are circulated and transported by the turntable 30, pass through the processing space 59 repeatedly, thereby performing the membrane processing.

The window member 52 is a flat plate made of a dielectric material such as quartz having a shape similar to the horizontal cross section of the cylindrical body 51. This window member 52 is provided to cover the opening of the cylindrical body 51, and separates the processing space 59 into which the process gas G2 in the chamber 10 is introduced from the inside of the cylindrical body 51. The window member 52 may be made of a dielectric material such as alumina, or a semiconductor material such as silicon.

The antenna 53 is a conductor wound into a coil shape, and is disposed in the internal space of the cylindrical body 51, which is isolated from the processing space 59 in the chamber 10 by the window member 52, and generates an electric field by passing an alternating current through it. It is desirable to dispose the antenna 53 near the window member 52 so that the electric field generated by the antenna 53 is efficiently introduced into the processing space 59 through the window member 52. An RF power supply 54 that applies a high frequency voltage is connected to the antenna 53. A matching box 55, which is a matching circuit, is connected to the output side of the RF power supply 54. The matching box 55 stabilizes the plasma discharge by matching the impedance on the input side and the output side.

The oxygen gas introduction unit 56 introduces the process gas G2 into the processing space 59. The oxygen gas introduction unit 56 has a supply source of the process gas G2, such as a cylinder (not shown), and a pipe 57. The pipe 57 is connected to the supply source of the process gas G2, penetrates the chamber 10 while hermetically sealing it, and extends into the interior of the chamber 10, with its end opening as a gas introduction port 58. The gas introduction port 58 opens into the processing space 59 between the window member 52 and the rotary table 30, and introduces the process gas G2. The process gas G2 is a mixed gas containing oxygen (O ₂ ) gas and a rare gas such as argon gas.

In such a film processing section 50, a high-frequency voltage is applied to the antenna 53 from the RF power supply 54. This causes a high-frequency current to flow through the antenna 53, generating an electric field due to electromagnetic induction. The electric field is generated in the processing space 59 through the window member 52, which converts the process gas G2 into plasma and generates inductively coupled plasma. This plasma generates oxygen species containing oxygen ions, which collide with the yttrium film on the workpiece W and bond with the yttrium atoms. As a result, the yttrium film on the workpiece W is oxidized to become an yttria (yttrium oxide) film. The workpiece W is circulated and transported by the rotating table 30 and rotates around the chamber 10 many times, passing alternately through the film forming section 40 and the film processing section 50, and film forming and film processing are alternately repeated on the workpiece W to grow a film of the desired thickness.

In such a film forming apparatus 1, an adhesion prevention plate 12 is removably provided in the chamber 10. The adhesion prevention plate 12 prevents the film forming material scattered from the film forming processing unit 40 from adhering to the inside of the chamber 10. The adhesion prevention plate 12 is, for example, a metal plate. On the surface of the adhesion prevention plate 12, for example, a plasma sprayed film of aluminum or aluminum alloy is formed, and the surface is roughened by sandblasting or the like. This increases the adhesion with the deposited film and suppresses peeling of the film material.

By combining multiple adhesion prevention plates 12, for example, they are arranged to cover the inner peripheral surface 10c of the chamber 10. Although not shown, adhesion prevention plates 12 are also arranged on the rotating table 30 at locations other than the tray 60. Adhesion prevention plates 12 are also arranged on the peripheral surface of the box-shaped shielding member 11. Furthermore, adhesion prevention plates 12 are also provided around the target 412 in the processing space 41 of the film formation processing unit 40. In this way, the adhesion prevention plates 12 are appropriately arranged in locations where the film formation material may adhere.

The adhesion prevention plate 12 is removed by opening the chamber 10 for maintenance. The ceiling 10a of the chamber 10 is removably attached to the side wall 10c. The ceiling 10a is attached via a sealing member such as an O-ring (not shown), thereby sealing the inside of the chamber 10. By removing the ceiling 10a, maintenance including cleaning the inside of the chamber 10 becomes possible. That is, the adhesion prevention plate 12 is removed, the film deposited on the surface is removed by sandblasting, and then washed with pure water. After washing and drying, the adhesion prevention plate 12 is transported in a vacuum-packed state to the film forming apparatus 1, opened, and attached to the film forming apparatus 1 again.

The various elements of the film forming apparatus 1 are controlled by a control unit 80. This control unit 80 is a processing device that includes a PLC (Programmable Logic Controller) and a CPU (Central Processing Unit), and stores programs that describe the control contents, setting values, threshold values, etc.

The control modes of the control unit 80 include at least a full-scale operation mode and a getter material production mode, and the control unit 80 controls various elements constituting the film forming apparatus 1, such as the exhaust unit 20, the sputtering gas introduction unit 419, the oxygen gas introduction unit 428, the power supply unit 416, the RF power supply 424, the rotating table 30, and the transfer chamber 70, depending on the mode. There may be other operation modes besides the full-scale operation mode and the getter material production mode.

In the main operation mode, an yttria film is formed on the workpiece W. In the getter material preparation mode, the operation is performed without the workpiece W being brought into the chamber 10, and a getter material is prepared in the chamber 10. The getter material is a material that produces a getter effect by adsorbing moisture, and is prepared on the rotating table 30 by the film forming apparatus 1 under the control of the control unit 80. This getter material is, for example, a tray 60 that is placed on the rotating table 30 when forming an yttria film on the workpiece W. By forming an yttrium film, which is the same as the film forming material for the workpiece W, on the tray 60 that does not hold the workpiece W, the tray 60 becomes the getter material.

However, as shown in FIG. 3, which is a schematic perspective view of the tray 60, a recess 61 that matches the shape of the workpiece W is formed on the surface of the tray 60. The workpiece W is held on the tray 60 by being fitted into this recess 61. When forming an yttrium film on the tray 60, a flat plate 62 is fitted into the recess 61 of the tray 60. The flat plate 62 has the same shape and size as the recess 61, and does not provide any room for yttrium particles to enter between the recess 61 and the flat plate 62. By fitting this flat plate 62 into the recess 61, the yttrium film is not formed on the recess 61 that comes into contact with the workpiece W. Therefore, when the workpiece W is fitted into the recess 61 of the tray 60 on which the yttrium film has been formed, the workpiece W on which the yttria film is to be formed is not metal-contaminated with yttrium.

Figure 4 is a flowchart showing the film formation operation including the control of the control unit 80, which controls various elements in the getter material preparation mode. First, before moving to the getter material preparation mode, maintenance is performed inside the chamber 10 (step S01). During the maintenance, the chamber 10 is opened to the atmosphere, the adhesion prevention plate 12 is removed from the chamber 10, and a new adhesion prevention plate 12 or a cleaned adhesion prevention plate 12 is installed in the chamber 10.

Next, the flat plate 62 is fitted into the recess 61 (step S02). Then, the tray 60 with the flat plate 62 fitted without the workpiece W placed thereon is carried into the chamber 10 via the transfer chamber 70 (step S03). Then, these trays 60 are lined up at equal circumferential positions on the rotating table 30 (step S04). That is, the rotating table 30 sequentially moves the empty holding parts 32 to the loading positions from the transfer chamber 70. The holding parts 32 individually hold each of the trays 60 carried in by the transport means. In this way, all of the trays 60 with the flat plates 62 fitted in place of the workpieces W are placed on the rotating table 30.

From this point, the control unit 80 switches to a getter material preparation mode, and the control unit 80 operates the exhaust unit 20 to reduce the pressure in the chamber 10 to a predetermined level (step S05). The control unit 80 then controls the turntable 30 to rotate the turntable 30 with the tray 60 placed on it at a predetermined rotation speed (step S06).

When the rotation of the turntable 30 reaches a predetermined rotation speed, the control unit 80 controls the sputtering gas inlet 419 of the film forming processing unit 40 to supply sputtering gas G1, such as argon gas, between the target 412 and the turntable 30 through the gas inlet 417 until the processing space 41 of the film forming processing unit 40 reaches a predetermined processing pressure (step S07).

When the processing space 41 of the film forming processing unit 40 reaches a predetermined processing pressure by the sputtering gas G1, the control unit 80 controls the power supply unit 416 to apply a voltage to the target 412 containing yttrium as a film forming material through the electrode 414 (step S08). This converts the sputtering gas G1 into plasma. Ions generated by the plasma collide with the target 412 and knock out yttrium particles. Yttrium particles are deposited on the surface of the tray 60 passing through the film forming processing unit 40 each time it passes, forming an yttrium film. In this getter material production mode, the film processing unit 50 is not operated. That is, the tray 60 passes through the section in which the film processing unit 50 is located without being film-processed by the film processing unit 50.

The control unit 80 determines whether the yttrium film formed on the tray 60 has reached a predetermined film thickness (step S09). The predetermined film thickness is preferably, but not limited to, 200 nm or more and less than 300 nm.

For a given film thickness, the relationship between the film thickness of the yttrium film formed on the tray 60 and the degree of vacuum in the chamber 10 is as shown in Table 1 below. In Table 1, the degree of vacuum in the chamber 10 was measured after the tray 60 on which the yttrium film of each thickness between 0 nm and 300 nm was formed was left in the chamber 10 after the vacuum was drawn again after maintenance, and about 12 hours had passed since the tray 60 was left in the chamber 10. In Table 1, 0 nm indicates that the tray 60 on which the yttrium film had not yet been formed was left in the chamber 10.

As shown in Table 1, a film thickness of 200 nm or more lowered the pressure in the chamber 10, in other words, increased the degree of vacuum, compared to a film thickness of less than 200 nm. In other words, the partial pressure of moisture in the chamber 10 decreased. Furthermore, even if a tray 60 on which an yttrium film with a thickness of 300 nm or more was placed in the chamber 10, the degree of vacuum did not increase any further. Therefore, the thickness of the yttrium film is preferably 200 nm or more, and less than 300 nm is preferable to prevent consumption of the target 412.

The thickness of the yttrium film may be estimated based on the cumulative film formation time, for example, by determining the film formation time required to reach the target film thickness in advance by simulation, calculation, or actual measurement using a step gauge.

When the yttrium film formed on the tray 60 reaches a predetermined thickness (step S09, Yes), the control unit 80 controls the power supply unit 416 to stop the voltage application to the target 412 through the electrode 414 (step S10). Then, the control unit 80 controls the sputtering gas inlet 419 of the film forming processing unit 40 to stop the supply of the sputtering gas G1 through the gas inlet 417 (step S11). Furthermore, the control unit 80 controls the turntable 30 to stop the rotation of the turntable 30 on which the tray 60 is placed (step S12). Note that while the yttrium film formed on the tray 60 does not reach a predetermined thickness (step S09, No), the control unit 80 does not stop the voltage application to the target 414, stop the supply of the sputtering gas G1, or stop the rotation of the turntable 30. That is, the voltage application to the target 414, the supply of the sputtering gas G1, and the rotation of the turntable 30 are maintained.

This produces a getter material consisting of the tray 60 and the yttrium film formed on the tray 60. This getter material has the function of adsorbing moisture-related components such as _O2 , _H2 , and _H2O by the getter effect, thereby lowering the moisture partial pressure in the chamber 10. The getter effect is the effect of adsorbing gas molecules by a chemical reaction in a vacuum. By holding such a getter material on the turntable 30 in the chamber 10, the moisture partial pressure in the chamber 10 can be lowered not only in the film forming processing section 40, but also in the film processing section 50 and other locations.

The tray 60 is used when the flat plate 62 is removed and an yttria film is formed on the workpiece W in the normal operation mode. That is, the workpiece W is held on the tray 60 on which the yttrium film is formed except for the recess 61, and is carried into the chamber 10, where it passes through the film forming processing section 40 and the film processing section 50, and the yttria film is formed.

In addition, in the film formation operation for producing the getter material, after the maintenance is performed by opening the chamber to the atmosphere, the chamber 10 may be preheated before proceeding to the production of the getter material. First, with the gate valve GV2 closed, the gate valve GV1 between the chamber 10 and the transfer chamber 70 is opened, and the exhaust unit 20 starts exhausting. This reduces the pressure in the chamber 10 and the transfer chamber 70. The transfer chamber 70 is equipped with a cooling mechanism, and the cooling mechanism is cooled to an extremely low temperature below freezing. Then, the oxygen gas introduction unit 56 of the film processing unit 50 starts introducing argon gas and oxygen gas, the RF power supply 54 of the plasma generator is turned on, and the process gas G2 introduced into the processing space 59 is turned into plasma. The heat of the plasma heats the turntable 30 passing through the processing space 59 by radiant heat, and the chamber 10 is further heated through the turntable 30. This preheating causes the moisture adsorbed to the components in the chamber 10 to desorb and be adsorbed by the cooling mechanism of the transfer chamber 70, thereby discharging the moisture from the chamber 10 and reducing the partial pressure of the moisture within the chamber 10.

(Action and Effect)
As described above, the film forming apparatus 1 of the present embodiment includes the chamber 10, the turntable 30, the film forming processing section 40, the film processing section 50, and the control section 80. The chamber 10 can be evacuated inside. The turntable 30 is provided in the chamber 10, holds the workpiece W, and circulates and transports the workpiece W along a circular trajectory L. The film forming processing section 40 has a target 412 made of a film forming material containing yttrium, and a plasma generator that converts the sputtering gas G1 introduced between the target 412 and the turntable 30 into plasma, applies a voltage to the target 412, and knocks out yttrium particles from the target 412 toward the turntable 30 to form an yttrium film on the workpiece W held on the turntable 30. The film processing section 50 has an oxygen gas introduction section 56 that introduces oxygen gas, and a plasma generator that converts the oxygen gas into plasma, and oxidizes the yttrium film formed on the workpiece W.

The control unit 80 controls the operation of the turntable 30, the film forming processing unit 40, and the film processing unit 50. The control unit 80 rotates the turntable 30 without holding the workpiece W, causes the plasma generator of the film forming processing unit 40 to generate plasma from the sputtering gas, applies a voltage to the target 412, and causes the yttrium particles to be ejected toward the turntable 30, which is not holding the workpiece W.

As a result, an yttrium film is formed on the tray 60 installed on the rotating table 30 without holding the workpiece W. The tray 60 becomes a getter material that absorbs moisture, and is circulated and transported within the chamber 10 before the yttria film is formed on the workpiece W. Therefore, moisture can be removed at various locations within the chamber 10 without complicating the device configuration by arranging heating units at various locations within the chamber 10, and the degree of vacuum within the chamber 10 can be increased. Note that any member that can be installed on the rotating table 30 may be used as the getter material by forming an yttrium film, not limited to the tray 60. For example, an yttrium film may be formed on the surface of the rotating table 30, and the rotating table 30 may be used as the getter material. Also, for example, the getter material may be a plate-shaped member rather than a member that holds the workpiece W, such as a tray.

The tray 60 is also formed with a recess 61 into which the workpiece W is fitted. When the tray 60 is used as a getter material, a flat plate 62 is fitted into the recess 61, and the control unit 80 rotates the turntable 30 on which the tray 60 with the flat plate 62 fitted into the recess 61 instead of the workpiece W is placed. As a result, no yttrium film is formed in the recess 61 into which the workpiece W is fitted. Therefore, when the workpiece W is fitted into the tray 60, the yttrium film comes into contact with the workpiece W, reducing the risk of metal contamination of the workpiece W.

Other Embodiments
Although the embodiment of the present invention and the modified examples of each part have been described, these embodiments and the modified examples of each part are presented as examples and are not intended to limit the scope of the invention. These novel embodiments described above can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims.

1 Film forming apparatus 10 Chamber 10a Ceiling 10b Inner bottom surface 10c Inner peripheral surface 11 Box-shaped shield member 12 Adhesion prevention plate 20 Exhaust section 30 Rotary table 31 Motor 32 Holding section 40 Film forming processing section 41 Processing space 412 Target 413 Backing plate 414 Electrode 416 Power supply section 417 Gas inlet 418 Pipe 419 Sputtering gas inlet section 50 Film processing section 51 Cylindrical body 52 Window member 53 Antenna 54 RF power supply 55 Matching box 56 Oxygen gas inlet section 57 Pipe 58 Gas inlet 59 Processing space 60 Tray 61 Recess 62 Flat plate 70 Transfer chamber 71 Load lock section 80 Control section

Claims (7)

a chamber capable of creating a vacuum therein;
a rotary table provided within the chamber, which holds a workpiece and circulates the workpiece along a circular path;
a film forming processing section including a target made of a film forming material containing yttrium, a plasma generator that applies a voltage to the target and converts a sputtering gas introduced between the target and the rotary table into plasma, and knocks out yttrium particles from the target toward the rotary table to form a yttrium film on the workpiece held on the rotary table;
a film processing section having an oxygen gas introduction section for introducing oxygen gas and a plasma generator for converting the oxygen gas into plasma, and for oxidizing the yttrium film formed on the workpiece;
A control unit that controls operations of the turntable, the film forming unit, and the film processing unit;
Equipped with
the control unit rotates the turntable in a state where the workpiece is not held, applies a voltage to the target, and strikes yttrium particles toward the turntable where the workpiece is not held;
A film forming apparatus characterized by the above. The control unit has a main operation mode in which the operation of the film forming processing unit and the film processing unit is controlled in a state in which the workpiece is held, and a getter material preparation mode in which the operation of the film forming processing unit and the film processing unit is controlled in a state in which the workpiece is not held,
2. The film forming apparatus according to claim 1, A tray is placed on the rotary table and holds the workpiece,
the control unit rotates the turntable on which the tray is placed while not holding the workpiece, applies a voltage to the target, and forms a yttrium film on the tray;
3. The film forming apparatus according to claim 1 or 2, The tray has a recess into which the workpiece is fitted,
the control unit rotates the turntable on which the tray is placed, the turntable having a flat plate fitted in the recess instead of the workpiece, when forming a yttrium film on the tray;
4. The film forming apparatus according to claim 3, placing the tray having the yttrium film formed on its surface and holding the workpiece on the turntable, forming an yttrium film on the workpiece in the film forming processing unit, and oxidizing the yttrium film formed on the workpiece in the film processing unit;
5. The film forming apparatus according to claim 3 or 4, a chamber capable of creating a vacuum therein;
a rotary table provided within the chamber, which holds a workpiece and circulates the workpiece along a circular path;
a film forming processing section including a target made of a film forming material containing yttrium, a plasma generator that applies a voltage to the target and converts a sputtering gas introduced between the target and the rotary table into plasma, and knocks out yttrium particles from the target toward the workpiece that is circulated and transported by the rotary table, thereby forming a yttrium film on the workpiece;
a film processing section having an oxygen gas introduction section for introducing oxygen gas and a plasma generator for converting the oxygen gas into plasma and oxidizing the formed yttrium film;
A film forming method using a film forming apparatus comprising:
rotating the rotary table in a state where the workpiece is not held, applying a voltage to the target, and striking the yttrium particles toward the rotary table where the workpiece is not held;
The film forming method is characterized by the above. placing a tray having a surface on which an yttrium film is formed and holding the workpiece on the turntable, forming an yttrium film on the workpiece in the film forming processing unit, and oxidizing the yttrium film formed on the workpiece in the film processing unit;
7. The film forming method according to claim 6,

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