阅读说明：本技术 成膜装置以及成膜方法 (Film forming apparatus and film forming method ) 是由 小野大祐 伊藤昭彦 于 2020-04-23 设计创作，主要内容包括：本发明提供一种成膜装置以及成膜方法,其可低成本且高效率地形成氢化硅膜。所述成膜装置包括：搬送部(30),具有循环搬送工件(10)的旋转台(31)；成膜处理部(40),具有包含硅材料的靶(42)、及对被导入靶(42)与旋转台(31)之间的溅射气体(G1)进行等离子体化的等离子体产生器,通过溅射而在工件(10)形成硅膜；以及氢化处理部(50),具有导入含有氢气的工艺气体(G2)的工艺气体导入部(58)、及对工艺气体(G2)进行等离子体化的等离子体产生器,对已形成在工件(10)的硅膜进行氢化,搬送部(30)以使工件(10)交替地穿过成膜处理部(40)与氢化处理部(50)的方式进行搬送。(The invention provides a film forming apparatus and a film forming method, which can form a silicon hydride film with low cost and high efficiency. The film forming apparatus includes: a conveying section (30) having a rotary table (31) for circularly conveying the workpiece (10); a film formation processing unit (40) which has a target (42) containing a silicon material and a plasma generator for converting a sputtering gas (G1) introduced between the target (42) and the turntable (31) into a plasma, and which forms a silicon film on the workpiece (10) by sputtering; and a hydrogenation unit (50) which has a process gas introduction unit (58) for introducing a process gas (G2) containing hydrogen gas and a plasma generator for converting the process gas (G2) into plasma, and which hydrogenates the silicon film formed on the workpiece (10), and which transports the workpiece (10) by the transport unit (30) so that the workpiece (10) alternately passes through the film formation unit (40) and the hydrogenation unit (50).)

1. A film forming apparatus, comprising:

a conveying part having a rotary table for circularly conveying the workpiece;

a film formation processing unit having a target containing a silicon material and a plasma generator for converting a sputtering gas introduced between the target and the turntable into a plasma, and forming a silicon film on the workpiece by sputtering; and

a hydrogenation treatment section having a process gas introduction section for introducing a process gas containing hydrogen gas and a plasma generator for converting the process gas into plasma, and hydrogenating the silicon film formed on the workpiece,

the conveying section conveys the workpiece so that the workpiece alternately passes through the film formation processing section and the hydrogenation processing section.

2. The film forming apparatus according to claim 1,

the film formation processing unit includes a sputtering gas introduction unit that introduces a sputtering gas containing hydrogen.

3. The film forming apparatus according to claim 2,

the sputtering gas introduction part introduces the same sputtering gas as the process gas.

4. The film forming apparatus according to any one of claims 1 to 3,

the hydrogen concentration in the process gas is below 3%.

5. The film forming apparatus according to any one of claims 1 to 4,

the thickness of the silicon film formed each time the silicon film passes through the film formation processing section is 0.5nm or less.

6. The film forming apparatus according to any one of claims 1 to 5,

comprises a chamber in which the film formation processing section and the hydrogenation processing section are disposed in different regions,

the film formation processing section and the hydrogenation processing section are provided on a circumferential transport path of the turntable.

7. A film forming method is characterized by comprising:

a cyclic conveying step of cyclically conveying the workpiece by a conveying part having a rotary table;

a film formation step of forming a silicon film on the workpiece by sputtering in a film formation processing section having a target containing a silicon material and a plasma generator for converting a sputtering gas introduced between the target and the turntable into a plasma; and

A hydrogenation step of hydrogenating a silicon film formed on the workpiece by a hydrogenation treatment unit having a process gas introduction unit into which a process gas containing hydrogen is introduced and a plasma generator which converts the process gas into plasma,

the conveying section conveys the workpiece so that the workpiece alternately passes through the film formation processing section and the hydrogenation processing section.

Technical Field

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

Background

In a silicon (Si) film used for an optical film or the like, since electrical properties become unstable and optical properties become unstable when a dangling bond (dangling bond) is present in a silicon atom in the film, it is necessary to form a hydrogen terminated Si — H film (hereinafter, referred to as a hydrogenated silicon film) by bonding a hydrogen (H) atom to the dangling bond to become a stable state. As a film forming apparatus for forming a silicon film, there is an apparatus for depositing silicon particles on a substrate by sputtering. Silicon deposited by sputtering is amorphous (noncrystalline), and has many dangling bonds compared with crystalline silicon, but can be stabilized by hydrogen termination.

In such a film deposition apparatus, a substrate is supported and fixed at a position facing a target of a silicon material in a chamber as a closed container. Then, a sputtering gas containing hydrogen gas is introduced into the chamber, and a high-frequency power is applied to the target, thereby turning the sputtering gas into plasma. The active species generated by the plasma eject silicon particles from the target and deposit them on the substrate. At this time, dangling bonds of silicon atoms are bonded to hydrogen atoms contained in the sputtering gas, thereby performing hydrogen termination.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent application laid-open No. Hei 07-90570

Disclosure of Invention

[ problems to be solved by the invention ]

When the film formation is performed and the hydrogen termination is performed as described above, the efficiency of the bonding between silicon and hydrogen is not good. Therefore, the ratio of hydrogen gas (hydrogen concentration) in the sputtering gas must be increased. However, if the hydrogen concentration is increased, the possibility of explosion of the high-concentration hydrogen due to reaction with oxygen present inside the film forming apparatus or heat increases. Therefore, when the hydrogen concentration to be used is increased, the safety is ensured by setting the building or the device to the explosion-proof standard. As a result, the cost of the equipment increases. Even if film formation is performed in a chamber by a sputtering gas containing hydrogen gas, although hydrogen termination of silicon atoms formed in the surface layer of the silicon film of the substrate is easily performed, the hydrogen atoms hardly reach the inside of the silicon film, and the silicon atoms inside the film easily remain dangling bonds. That is, it is difficult to efficiently terminate the entire silicon film including the inside thereof with hydrogen.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a film formation apparatus and a film formation method capable of forming a silicon hydride film at low cost and with high efficiency.

[ means for solving problems ]

In order to achieve the above object, a film forming apparatus according to the present invention includes: a conveying part having a rotary table for circularly conveying the workpiece; a film formation processing unit having a target containing a silicon material and a plasma generator for converting a sputtering gas introduced between the target and the turntable into a plasma, and forming a silicon film on the workpiece by sputtering; and a hydrogenation unit having a process gas introduction unit for introducing a process gas containing hydrogen gas and a plasma generator for converting the process gas into plasma, and configured to hydrogenate the silicon film formed on the workpiece, wherein the transfer unit transfers the workpiece so as to alternately pass through the film formation unit and the hydrogenation unit.

Further, the film forming method of the present invention includes: a cyclic conveying step of cyclically conveying the workpiece by a conveying part having a rotary table; a film formation step of forming a silicon film on the workpiece by sputtering in a film formation processing section having a target containing a silicon material and a plasma generator for converting a sputtering gas introduced between the target and the turntable into a plasma; and a hydrogenation step of hydrogenating a silicon film formed on the workpiece by a hydrogenation unit having a process gas introduction unit into which a process gas containing hydrogen is introduced and a plasma generator which converts the process gas into plasma, wherein the transfer unit transfers the workpiece so as to alternately pass through the film formation unit and the hydrogenation unit.

[ Effect of the invention ]

According to the present invention, a silicon hydride film can be formed at low cost and with high efficiency.

Drawings

Fig. 1 is a perspective plan view schematically showing the configuration of a film deposition apparatus according to the present embodiment.

FIG. 2 is a sectional view taken along line A-A in FIG. 1, and is a detailed view of the internal structure of the film forming apparatus in the embodiment of FIG. 1 as viewed from the side.

Fig. 3 is a flowchart of a process performed by the film deposition apparatus according to the present embodiment.

Fig. 4 (a) to 4 (I) are schematic views showing a process of processing a workpiece by the film deposition apparatus according to the present embodiment.

Fig. 5 is a graph showing the relationship between the extinction coefficient of the silicon film and the wavelength.

[ description of symbols ]

10: workpiece

11: hydrogenated silicon film

12: film(s)

20: chamber

20 a: top part

20 b: inner bottom surface

20 c: inner peripheral surface

21: exhaust port

22: partition part

30: conveying part

31: rotary table

32: motor with a stator having a stator core

33: holding part

34: tray

40: film formation processing section

41: treatment space

42: target

43: support plate

44: electrode for electrochemical cell

46: power supply unit

47: gas inlet

48: piping

49: sputtering gas introduction part

50: hydrotreating section

51: cylindrical body

52: window component

53: antenna with a shield

54: RF power supply

55: matching box

56: gas inlet

57: piping

58: process gas introduction part

59: treatment space

60: load lock

70: control device

80: exhaust part

90: supply source

91: rare gas supply unit

92: hydrogen gas supply unit

93A, 93B: mixing device

100: film forming apparatus

910. 920: gas storage cylinder

911A, 911B, 921A, 921B: piping

912A, 912B, 922A, 922B: flow rate controller

G1: sputtering gas

G2: process gas

L: conveying path

S01-S09: step (ii) of

Detailed Description

An embodiment of a film deposition apparatus according to the present invention will be described in detail with reference to the drawings.

[ summary ]

The film formation apparatus 100 shown in fig. 1 is an apparatus for forming a silicon hydride film on a workpiece 10 by sputtering. The workpiece 10 is a light-transmitting substrate such as quartz or glass, and the film formation apparatus 100 forms a hydrogen-terminated silicon (Si — H) film on the surface of the workpiece 10. The silicon film to be formed is amorphous, that is, an amorphous silicon film, and silicon atoms constituting the film have dangling bonds. In the present specification, "hydrogenation" and "hydrogen termination" have the same meaning. Therefore, in the following description, the hydrogen treatment means a treatment for hydrogen termination.

The film forming apparatus 100 includes a chamber 20, a transfer unit 30, a film forming process unit 40, a hydrogenation process unit 50, a load-lock unit 60, and a control unit 70. The chamber 20 is a container whose inside can be made vacuum. The chamber 20 has a cylindrical shape, and the inside thereof is divided by partitions 22 into a plurality of sectors in a fan shape. The film formation processing section 40 is disposed in one region, the hydrogenation processing section 50 is disposed in the other region, and the load lock section 60 is disposed in the other region. That is, the film formation processing unit 40, the hydrogenation processing unit 50, and the load lock unit 60 are disposed in different regions in the chamber 20.

The film formation processing section 40 and the hydrogenation processing section 50 are disposed in one region. The workpiece 10 is rotated several times in the circumferential direction in the chamber 20, and thereby alternately goes around and passes through the film formation processing section 40 and the hydrogenation processing section 50, and the formation of a silicon film and the hydrogenation of the silicon film are alternately repeated on the workpiece 10, whereby a hydrogenated silicon film having a desired thickness is grown. In addition, when the hydrogen concentration is increased, two or more hydrogenation processing units 50 may be disposed in the film formation processing unit 40. That is, the hydrotreating section 50 may be disposed in two or more regions. Even if two or more hydrotreating portions 50 are disposed, the present embodiment includes "alternately passing through film formation processing portions and hydrotreating portions" as long as the film formation processing or the processing other than the hydrotreating processing is not included between the hydrotreating processing and the film formation processing, as in film formation → hydrotreating → film formation … ….

As shown in fig. 2, the chamber 20 is surrounded by a disk-shaped top 20a, a disk-shaped inner bottom surface 20b, and an annular inner peripheral surface 20 c. The partition portion 22 is a rectangular wall plate radially disposed from the center of the columnar shape, and extends from the top portion 20a toward the inner bottom surface 20b, without reaching the inner bottom surface 20 b. That is, a cylindrical space is secured on the inner bottom surface 20b side.

A rotary table 31 for conveying the workpiece 10 is disposed in the columnar space. The lower end of the partition 22 is open to a gap through which the workpiece 10 placed on the conveying unit 30 passes, and faces the placement surface of the workpiece 10 on the rotary table 31. The partition 22 divides the film formation processing section 40 and the hydrogenation processing section 50 into a processing space 41 and a processing space 59 in which the workpiece 10 is processed. That is, the film formation processing section 40 and the hydrogenation processing section 50 have a processing space 41 and a processing space 59, respectively, which are smaller than the chamber 20 and are separated from each other. This can suppress the diffusion of the sputtering gas G1 in the film formation processing section 40 and the process gas G2 in the hydrogenation processing section 50 into the chamber 20.

As will be described later, although the film formation processing unit 40 and the hydrogenation processing unit 50 generate plasma in the processing spaces 41 and 59, the pressure in the processing space divided into smaller spaces than the chamber 20 may be adjusted, so that the pressure adjustment can be easily performed and the discharge of the plasma can be stabilized. Therefore, if the above-described effects can be obtained, at least two partitions 22 may be provided so as to sandwich the film formation processing section 40 and two partitions 22 may be provided so as to sandwich the hydrogenation processing section 50 in a plan view.

Further, the chamber 20 is provided with an exhaust port 21. An exhaust unit 80 is connected to the exhaust port 21. The exhaust unit 80 includes piping, and a pump, a valve, and the like, which are not shown. The inside of the chamber 20 can be depressurized and vacuumed by the evacuation through the evacuation unit 80 via the evacuation port 21.

The conveying unit 30 includes a rotary table 31, a motor 32, and a holding unit 33, and circularly conveys the workpiece 10 along a conveying path L that is a circumferential trajectory. The turntable 31 has a disk shape and is largely expanded to such an extent that it does not contact the inner peripheral surface 20 c. The motor 32 continuously rotates at a predetermined rotational speed with the center of the circle of the turntable 31 as a rotational axis. The holding portion 33 is a groove, a hole, a protrusion, a jig, a fixture, or the like arranged at a circumferential or equivalent position on the upper surface of the turntable 31, and holds the tray 34 on which the workpiece 10 is placed by a mechanical chuck or an adhesive chuck. The workpieces 10 are arranged on the tray 34 in a matrix, for example, and six holding portions 33 are arranged on the rotary table 31 at 60 ° intervals. That is, the film deposition apparatus 100 can collectively perform film deposition on a plurality of workpieces 10 held by a plurality of holding sections 33, and thus productivity is very high.

The film formation processing section 40 generates plasma and exposes the target 42 containing the silicon material to the plasma. In this way, the film formation processing unit 40 deposits silicon particles, which are ejected by causing ions contained in the plasma to collide with the silicon material, on the workpiece 10 to form a film. As shown in fig. 2, the film formation processing section 40 includes: a sputtering source including a target 42, a support plate 43, and an electrode 44; and a plasma generator including a power supply unit 46 and a sputtering gas introduction unit 49.

The target 42 is a plate-like member containing a film-forming material which is deposited on the workpiece 10 to become a film. The film forming material of the present embodiment is a silicon material, and the target 42 serves as a supply source of silicon particles deposited on the workpiece 10. That is, the target 42 comprises a silicon material. The "target containing a silicon material" is acceptable even for a target containing a material other than silicon, such as a silicon alloy target, as long as it is a sputtering target capable of supplying silicon particles.

The target 42 is provided separately on the conveyance path L of the workpiece 10 mounted on the turntable 31. The target 42 is held on the ceiling 20a of the chamber 20 so that the surface thereof faces the workpiece 10 mounted on the turntable 31. For example, three targets 42 are provided. The three targets 42 are disposed at positions arranged at the vertices of a triangle in plan view.

The support plate 43 is a support member that holds the target 42. The support plate 43 individually holds each target 42. The electrodes 44 are conductive members for applying power to the targets 42 individually from the outside of the chamber 20, and are electrically connected to the targets 42. The power applied to each target 42 may be individually varied. The sputtering source may include a magnet, a cooling mechanism, and the like as needed.

The power supply unit 46 is, for example, a Direct Current (DC) power supply to which a high voltage is applied, and is electrically connected to the electrode 44. The power supply unit 46 applies power to the target 42 via the electrode 44. The turntable 31 has the same potential as the grounded chamber 20, and a high voltage is applied to the target 42 side to generate a potential difference. For high-Frequency sputtering, the power supply unit 46 may be a Radio Frequency (RF) power supply.

As shown in fig. 2, the sputtering gas introducing section 49 introduces a sputtering gas G1 into the chamber 20. The sputtering gas introduction section 49 includes a supply source 90 of sputtering gas G1, a pipe 48, and a gas introduction port 47. The pipe 48 is connected to a supply source 90 of sputtering gas G1, penetrates the chamber 20 in a gas-tight manner, extends into the chamber 20, and has an end opening as a gas inlet 47.

The gas inlet 47 opens between the turntable 31 and the target 42, and introduces a sputtering gas G1 for film formation into the processing space 41 formed between the turntable 31 and the target 42. As the sputtering gas G1, a rare gas, suitably argon (Ar) gas or the like, can be used. In addition, hydrogen gas is added to the sputtering gas G1 in the present embodiment. The hydrogen concentration in the sputtering gas G1 is, for example, a low concentration of 3% or less. The hydrogen concentration in the sputtering gas G1 is the proportion (weight percentage) of hydrogen in the sputtering gas G1 (rare gas + hydrogen).

The supply source 90 of the sputtering gas G1 controls the partial pressures of the rare gas and the hydrogen gas introduced into the sputtering gas G1 to supply the sputtering gas G1 into the chamber 20. Specifically, the supply source 90 includes: a rare gas supply part 91, a hydrogen gas supply part 92, and a mixer 93A for mixing a rare gas and hydrogen gas. The rare gas supply section 91 includes: a gas bomb 910 containing a rare gas, a pipe 911A for introducing the rare gas, and a flow rate controller (MFC) 912A for adjusting the flow rate of the rare gas. The hydrogen gas supply portion 92 includes: a cylinder 920 for storing hydrogen gas, a pipe 921A for introducing hydrogen gas, and a flow rate controller (MFC)922A for adjusting the flow rate of hydrogen gas. The mixer 93A mixes the rare gas adjusted to a predetermined flow rate by the flow rate controllers 912A and 922A with the hydrogen gas. The mixed gas of the rare gas and the hydrogen gas obtained in the mixer 93A is supplied as the sputtering gas G1 from the gas inlet 47 into the chamber 20.

In the film formation processing section 40, when the sputtering gas G1 is introduced from the sputtering gas introduction section 49 and the high voltage is applied to the target 42 from the power supply section 46 via the electrode 44, the sputtering gas G1 introduced into the processing space 41 formed between the turntable 31 and the target 42 turns into plasma, and active species such as ions are generated. Ions in the plasma collide with the target 42 comprising the silicon material to eject silicon particles.

Further, the workpiece 10 circularly conveyed by the rotary table 31 passes through the processing space 41. The ejected silicon particles are accumulated on the workpiece 10 while the workpiece 10 passes through the processing space 41, and a thin film of a silicon film is formed on the workpiece 10. The workpiece 10 is circularly conveyed by the rotary table 31 and repeatedly passes through the processing space 41, thereby performing the film deposition process.

The film thickness of the silicon film depends on the hydrogenation amount, i.e., the hydrogenation ratio, in a fixed time of the hydrogenation unit 50, and may be, for example, about 1 atomic level to 2 atomic levels (0.5nm or less). That is, every time the workpiece 10 passes through the processing space 41, the silicon particles are laminated with a film thickness of 1 atomic level or 2 atomic levels at a time, thereby forming a silicon film. Most of the silicon atoms thus converted into the silicon film have dangling bonds, and are in an unstable state in which unpaired electrons are present. However, the hydrogen gas contained in the sputtering gas G1 is converted into plasma to generate chemical species (atoms/molecules, ions, radicals, excited atoms/excited molecules, and the like). The hydrogen atoms contained in the chemical species are bonded to a part of dangling bonds of silicon atoms (hydrogen termination is performed). However, the hydrogen gas contained in the sputtering gas G1 has a low concentration, the amount of generated chemical species becomes relatively small, and the silicon atoms move vigorously before moving from the plasma to the workpiece 10, and therefore the bonding efficiency is low.

The hydrotreating section 50 generates inductively coupled plasma in the processing space 59 into which the process gas G2 containing hydrogen gas is introduced. That is, the hydrogen processing unit 50 converts the hydrogen gas into plasma to generate chemical species. The hydrogen atoms contained in the generated chemical species collide with the silicon film formed on the workpiece 10 by the film formation processing section 40 to bond with the silicon atoms. Thereby, the hydrotreating section 50 forms a silicon hydride film as a compound film. In this manner, the hydrogen-treated portion 50 is a plasma-treated portion for hydrogen-terminating silicon atoms of a silicon film on the workpiece 10 using plasma. As shown in fig. 2, the hydrotreating section 50 includes a plasma generator including a cylindrical body 51, a window member 52, an antenna 53, an RF power supply 54, a matching box 55, and a process gas introduction section 58.

The cylindrical body 51 covers the periphery of the processing space 59. As shown in fig. 2, the cylindrical body 51 is a cylinder having a rectangular shape with rounded corners in horizontal section and has an opening. The cylindrical body 51 is fitted into the ceiling portion 20a of the chamber 20 so that its opening faces the turntable 31 side in a separated manner, and projects into the internal space of the chamber 20. The cylindrical body 51 is made of the same material as the turntable 31. The window member 52 is a flat plate of a dielectric material such as quartz having a shape substantially similar to the horizontal cross section of the cylindrical body 51. The window member 52 is provided so as to close the opening of the cylindrical body 51, and separates the processing space 59 into which the process gas G2 containing hydrogen gas is introduced in the chamber 20 from the inside of the cylindrical body 51.

The processing space 59 is formed between the turntable 31 and the inside of the cylindrical body 51 in the hydrotreating section 50. The workpiece 10 circularly conveyed by the rotary table 31 passes through the processing space 59 repeatedly, thereby performing the hydrogenation process. The window member 52 may be a dielectric such as alumina, or may be a semiconductor such as silicon.

The antenna 53 is a conductor wound in a coil shape, is disposed in an internal space of the cylindrical body 51 separated from the processing space 59 in the chamber 20 by the window member 52, and generates an electric field by flowing an alternating current. The antenna 53 is preferably disposed in the vicinity of the window member 52 so that the electric field generated from the antenna 53 is efficiently introduced into the processing space 59 through the window member 52. The antenna 53 is connected to an RF power supply 54 for applying a high-frequency voltage. A matching box 55 as a matching circuit is connected in series to the output side of the RF power supply 54. The matching box 55 matches impedances on the input side and the output side, thereby stabilizing the discharge of the plasma.

As shown in fig. 2, the process gas introduction unit 58 introduces a process gas G2 containing hydrogen gas into the processing space 59. The process gas introduction part 58 includes a supply source 90 of a process gas G2, a pipe 57, and a gas introduction port 56. The pipe 57 is connected to a supply source 90 of the process gas G2, penetrates the chamber 20 while being hermetically sealed, extends into the chamber 20, and has an end opening as a gas introduction port 56.

The gas inlet 56 opens into the processing space 59 between the window member 52 and the turntable 31, and introduces the process gas G2. As the process gas G2, a rare gas, suitably argon or the like, can be used. In addition, hydrogen gas is added to the process gas G2 in the present embodiment. The hydrogen concentration in the process gas G2 is, for example, a low concentration of 3% or less. That is, the process gas G2 may use the same gas as the sputtering gas G1. The hydrogen concentration in the process gas G2 is the proportion (weight percentage) of hydrogen in the process gas G2 (rare gas + hydrogen).

The supply source 90 of the process gas G2 controls the introduction partial pressures of the rare gas and the hydrogen gas in the process gas G2 to supply the process gas G2 to the processing space 59. Specifically, the supply source 90 includes: a rare gas supply part 91, a hydrogen gas supply part 92, and a mixer 93B for mixing a rare gas and hydrogen gas. The rare gas supply section 91 includes: a gas cylinder 910 containing a rare gas, a pipe 911B for introducing the rare gas, and a flow rate controller (MFC)912B for adjusting the flow rate of the rare gas. The hydrogen gas supply portion 92 includes: a cylinder 920 for storing hydrogen gas, a pipe 921B for introducing hydrogen gas, and a flow rate controller (MFC)922B for adjusting the flow rate of hydrogen gas. The gas cylinders 910 and 920 are gas cylinders used in common with the supply source 90 of the sputtering gas G1. The mixer 93B mixes the rare gas adjusted to a predetermined flow rate by the flow rate controllers 912B and 922B with the hydrogen gas. The mixed gas of the rare gas and the hydrogen gas obtained in the mixer is supplied as the process gas G2 from the gas inlet 56 into the processing space 59.

In the hydrotreatment unit 50, a high-frequency voltage is applied from the RF power supply 54 to the antenna 53. Thereby, a high-frequency current flows through the antenna 53, and an electric field is generated by electromagnetic induction. An electric field is generated within the processing volume 59 via the window member 52, generating an inductively coupled plasma in the process gas G2. At this time, hydrogen species containing hydrogen atoms are generated and collide against the silicon film on the workpiece 10, whereby dangling bonds of the hydrogen atoms and silicon atoms are bonded. As a result, the silicon film on the workpiece 10 is hydrogen-terminated, and a stable hydrogenated silicon film is formed as a compound film. Since the silicon atoms deposited on the workpiece 10 are not randomly and vigorously moved and remain on the workpiece 10, even if the hydrogen concentration of the process gas G2 is low, the dangling bonds are easily bonded, and efficient hydrogen termination can be performed.

The load lock 60 is a device as follows: in a state where the vacuum of the chamber 20 is maintained, the tray 34 on which the unprocessed workpieces 10 are mounted is carried into the chamber 20 from the outside by a carrying member not shown, and the tray 34 on which the processed workpieces 10 are mounted is carried out to the outside of the chamber 20. The load lock 60 may be of a well-known structure, and thus, the description thereof will be omitted.

The control device 70 controls various elements constituting the film formation apparatus 100, such as the exhaust unit 80, the sputtering gas introduction unit 49, the process gas introduction unit 58, the power supply unit 46, the RF power supply 54, and the transfer unit 30. The control device 70 is a Processing device including a Programmable Logic Controller (PLC) or a Central Processing Unit (CPU), and stores a program describing control contents. Specific examples of the control include: the initial exhaust pressure of the film deposition apparatus 100, the power applied to the target 42 and the antenna 53, the flow rates, the introduction time and the exhaust time of the sputtering gas G1 and the process gas G2, the film deposition time, the rotation speed of the motor 32, and the like. The control device 70 can cope with various film formation standards.

[ operation ]

Next, the overall operation of the film formation apparatus 100 controlled by the control device 70 will be described. In addition, a film formation method in which film formation is performed by the film formation apparatus 100 in the following procedure, and a control method of the film formation apparatus 100 are also embodiments of the present invention. Fig. 3 is a flowchart of a process performed by the film formation apparatus 100 according to the present embodiment. First, the tray 34 on which the workpiece 10 is mounted is sequentially carried into the chamber 20 from the load lock portion 60 by the carrying means (step S01). In step S01, the turntable 31 sequentially moves the empty holders 33 to the positions where the trays 34 are loaded from the load lock 60. The holding portions 33 individually hold the trays 34 carried in by the conveying members. In this way, the entire tray 34 on which the workpiece 10 to be formed with the silicon hydride film is mounted is placed on the rotary table 31.

The inside of the chamber 20 is constantly depressurized by exhausting gas from the exhaust port 21 through the exhaust unit 80. When the pressure in the chamber 20 is reduced to a predetermined pressure (step S02), the turntable 31 on which the workpiece 10 is placed rotates to a predetermined rotational speed (step S03).

When the predetermined rotation speed is reached, a silicon film is first formed on the workpiece 10 by the film formation processing unit 40 (step S04). That is, the sputtering gas introducing section 49 supplies the sputtering gas G1 through the gas introducing port 47. A sputtering gas G1 is supplied to the periphery of the target 42 containing a silicon material. The power supply unit 46 applies a voltage to the target 42. Thereby, the sputtering gas G1 is made into plasma. Ions generated by the plasma collide with the target 42 to eject silicon particles.

When passing through the film formation processing section 40, a thin film 12 (fig. 4B) having silicon particles deposited on the surface thereof is formed on the unprocessed workpiece 10 (fig. 4 a). In the present embodiment, the deposition can be performed in such a manner that the film thickness is 0.5nm or less, that is, the deposition contains 1 to 2 silicon atoms, every time the deposition passes through the film formation processing section 40. When the sputtering gas G1 is turned into a plasma, hydrogen termination is performed by generating hydrogen species from the hydrogen gas in the sputtering gas G1, and bonding the hydrogen atoms contained therein to dangling bonds of a part of the silicon atoms. However, hydrogen termination at the time of film formation is limited to a minute amount.

In this way, the workpiece 10 on which the thin film 12 is formed passes through the film formation processing section 40 by the rotation of the rotary table 31, and passes through the hydrogenation processing section 50, in which process the silicon atoms of the thin film 12 are hydrogen-terminated (step S05). That is, the process gas introduction portion 58 supplies the process gas G2 containing hydrogen gas through the gas introduction port 56. The process gas G2 containing hydrogen gas is supplied to the processing space 59 sandwiched between the window member 52 and the turntable 31. The RF power supply 54 applies a high-frequency voltage to the antenna 53. An electric field generated by the antenna 53 through which a high-frequency current flows by application of a high-frequency voltage is generated in the processing space 59 via the window member 52. Further, the process gas G2 containing hydrogen gas, which has been supplied into the space, is excited by the electric field to generate plasma. Further, hydrogen atoms contained in the chemical species of hydrogen generated by the plasma collide with the thin film 12 on the workpiece 10, and are bonded to dangling bonds of silicon atoms, thereby converting the thin film 12 into the silicon hydride film 11 ((C) of fig. 4).

In this manner, in steps S04 and S05, the film formation process is performed by the work 10 passing through the process space 41 of the film formation process section 40 that is in operation, and the hydrogenation process is performed by the work 10 passing through the process space 59 of the hydrogenation process section 50 that is in operation. The meaning of "operating" is the same as the meaning of performing a plasma generation operation for generating plasma in the processing space 41 and the processing space 59 of each processing unit.

The operation of the hydrotreating section 50, in other words, the plasma generation operation (the introduction of the process gas G2 by the process gas introduction section 58 and the application of the voltage to the antenna 53 by the RF power source 54) may be started during a period until the workpiece 10 on which the first film formation is performed by the film formation section 40 reaches the hydrotreating section 50. If there is no problem in the surface of the workpiece 10 before the film formation, the operation of the film formation processing section 40, in other words, the plasma generation operation of the film formation processing section 40 (the introduction of the sputtering gas G1 by the sputtering gas introduction section 49 and the voltage application to the target 42 by the power supply section 46) may be started simultaneously with the plasma generation operation of the hydrogenation processing section 50, or the plasma generation operation of the hydrogenation processing section 50 may be started before the plasma generation operation of the film formation processing section 40 is started.

The turntable 31 continues to rotate until a predetermined time elapses before the silicon hydride film 11 having a predetermined thickness is formed on the workpiece 10, that is, before a predetermined time obtained in advance by simulation, experiment, or the like elapses (No at step S06). In other words, the workpiece 10 is cyclically passed through the film formation processing section 40 and the hydrogenation processing section 50 continuously until the hydrogenated silicon film 11 having a predetermined thickness is formed, and the film formation processing for depositing silicon particles on the workpiece 10 (step S04) and the hydrogenation processing for the deposited silicon particles (step S05) are alternately repeated (fig. 4D to 4I).

When a predetermined time has elapsed (Yes in step S06), the operation of the film formation processing section 40 is first stopped (step S07). Specifically, the introduction of the sputtering gas G1 by the sputtering gas introduction section 49 is stopped, and the voltage application to the target 42 by the power supply section 46 is stopped. Next, the operation of the hydrotreating unit 50 is stopped (step S08). Specifically, the introduction of the process gas G2 by the process gas introduction unit 58 is stopped, and the supply of the high-frequency power to the antenna 53 by the RF power source 54 is stopped. Then, the rotation of the rotary table 31 is stopped, and the tray 34 on which the workpieces 10 are placed is discharged from the load lock 60 (step S09).

In steps S07 and S08, the operation of the film formation processing unit 40 and the hydrogenation processing unit 50 is stopped, and a series of film formation processes are terminated.

The elements of the film formation processing section 40, the hydrogenation processing section 50, and the transfer section 30 are controlled so that a series of film formation processes are not terminated without performing a hydrogenation process after the film formation process. In other words, each element is controlled so that the film formation process of the silicon hydride is terminated by performing the hydrogenation process at the end of the film formation process and the hydrogenation process. In the present embodiment, the operation of the film formation processing section 40, in other words, the plasma generation operation in the film formation processing section 40 (the introduction of the sputtering gas G1 by the sputtering gas introduction section 49 and the voltage application to the target 42 by the power supply section 46) is stopped during the period until the workpiece 10 having passed through the film formation processing section 40 passes through the hydrogenation section 50 and reaches the film formation processing section 40 again.

In this manner, in the film formation apparatus 100, the workpiece 10 is alternately conveyed to the film formation processing section 40 and the hydrogenation processing section 50, and the alternate conveyance is repeated a plurality of times. Thus, the film formation process and the hydrogenation process are alternately performed a plurality of times. As shown in fig. 4 (a) to 4 (I), in the film formation process, a silicon material is sputtered to form a thin film 12 of silicon in which the ejected silicon particles are deposited on the workpiece 10. In the hydrogenation treatment, the process gas G2 containing hydrogen atoms is converted into plasma to generate a chemical species containing hydrogen atoms, the thin film 12 on the workpiece 10 is exposed to the chemical species, and hydrogenation is performed each time the thin film 12 is formed, thereby generating the silicon hydride film 11.

The thin film 12 formed by depositing silicon particles is hydrogenated to form a silicon hydride film 11, and the thin film 12 of silicon newly formed by further depositing silicon particles on the silicon hydride film 11 is hydrogenated. By the series of film formation processes of the silicon hydride film, the silicon hydride film 11 which is uniformly hydrogenated in the thickness direction is formed on the workpiece 10.

[ Effect ]

(1) As described above, the film deposition apparatus 100 of the present embodiment includes: a conveying unit 30 having a rotary table 31 for circularly conveying the workpiece 10; a film formation processing unit 40 having a target 42 containing a silicon material and a plasma generator for converting a sputtering gas G1 introduced between the target 42 and the turntable 31 into a plasma, and forming a silicon film on the workpiece 10 by sputtering; and a hydrogenation unit 50 having a process gas introduction unit 58 for introducing a process gas G2 containing hydrogen gas and a plasma generator for converting the process gas G2 into plasma, and configured to hydrogenate the silicon film formed on the workpiece 10, and the transfer unit 30 transfers the workpiece 10 so as to alternately pass through the film formation unit 40 and the hydrogenation unit 50.

In addition, the film forming method of the present embodiment includes: a circulating conveyance step of circulating the workpiece 10 by a conveyance unit 30 having a rotary table 31; a film formation step of forming a silicon film on the workpiece 10 by sputtering by a film formation processing section 40 having a target 42 and a plasma generator, the target 42 containing a silicon material, the plasma generator converting a sputtering gas G1 introduced between the target 42 and the turntable 31 into plasma; and a hydrogenation step of hydrogenating a silicon film formed on the workpiece 10 by a hydrogenation unit 50 having a process gas introduction unit 58 and a plasma generator, wherein the process gas introduction unit 58 introduces a process gas G2 containing hydrogen gas, the plasma generator converts the process gas G2 into plasma, and the transfer unit 30 transfers the workpiece 10 so as to alternately pass through the film formation unit 40 and the hydrogenation unit 50.

Therefore, the film formation and the hydrogenation by sputtering can be repeated by passing the workpiece 10 alternately through the film formation processing section 40 and the hydrogenation processing section 50 while the workpiece 10 is being conveyed cyclically by the rotary table 31. That is, by exposing the silicon atoms deposited by sputtering in the film formation processing part 40 to the process gas G2 plasma-converted by the hydrogenation processing part 50, the hydrogen atoms can be efficiently bonded to dangling bonds of the silicon atoms, and the proportion of the hydrogen-terminated silicon atoms in the film can be easily increased. Therefore, a silicon hydride film can be formed efficiently without increasing the hydrogen concentration of the process gas G2.

When the film is formed by sputtering while the workpiece 10 is stationary in the chamber, the film formation is easily performed and the film thickness is easily grown. When the film thickness is increased, even if the plasma-converted process gas G2 containing hydrogen is exposed, hydrogen termination is performed on the surface layer, but hydrogen atoms hardly reach the inside of the film, and silicon atoms with dangling bonds remaining remain in the film. In the present embodiment, while the workpiece 10 is being cyclically conveyed, the workpiece 10 is alternately passed through the film formation processing section 40 and the hydrogenation processing section 50, and the silicon atoms deposited by sputtering are exposed to the process gas G2, so that a thin film is formed, and the surface layer is hydrogen-capped in a state where the thickness of the thin film is thin, and the silicon atoms present in the finally formed film are hydrogen-capped by repeating this operation. Therefore, hydrogen termination can be performed uniformly in the thickness direction of the silicon film, and therefore, the uniformity of hydrogen termination of the entire silicon film can be improved.

In addition, when the film formation and the hydrogen termination of the workpiece 10 are performed in the common chamber as described above, the hydrogen concentration in the sputtering gas must be set to 10% or more in order to reduce dangling bonds. However, since there is a limit to the bonding ratio of dangling bonds to hydrogen atoms, if the hydrogen concentration in the gas is increased, hydrogen atoms that are not bonded to silicon atoms increase, the amount of hydrogen atoms present in the film becomes uneven, and the film characteristics deteriorate. To cope with this, a treatment for removing hydrogen atoms is required. As a result of diligent research on such technical common knowledge, the inventors of the present invention have found that, by repeating film formation and hydrogenation by sputtering while alternately passing the workpiece 10 through the film formation processing section 40 and the hydrogenation processing section 50 while cyclically conveying the workpiece 10 by the rotary table 31, dangling bonds can be reduced even if the hydrogenation processing is performed by a gas having a low hydrogen concentration, and hydrogen termination can be achieved very efficiently. Therefore, in this embodiment, it is also possible to reduce the residual hydrogen atoms not bonded to silicon atoms, which are generated in large amounts by increasing the hydrogen concentration, and it is not necessary to detach the hydrogen atoms.

(2) The film formation processing section 40 includes a sputtering gas introduction section 49 for introducing a sputtering gas G1 containing hydrogen gas. Therefore, even during film formation, the sputtering gas G1 containing hydrogen gas is converted into plasma, and the dangling bonds between the generated hydrogen species and the silicon atoms are bonded. As described above, although hydrogen termination is not sufficient only for hydrogenation during film formation, hydrogen termination of silicon atoms constituting a film can be improved by combination with hydrogenation in the hydrogenation processing section 50.

(3) The sputtering gas introduction unit 49 introduces a sputtering gas G1 that is the same as the process gas G2. By using the same gas, the gas source such as a gas cylinder can be used in both the film formation processing section 40 and the hydrogenation processing section 50, and the cost can be reduced.

(4) The hydrogen concentration in the process gas G2 is 3% or less. Since the hydrogen gas concentration at which the explosion risk occurs is usually about 4%, the possibility of explosion can be greatly reduced by setting the hydrogen gas concentration to 3% or less of a range in which the explosion risk can be safely used. Therefore, the equipment does not need explosion-proof specifications, and the cost can be greatly reduced.

(5) The thickness of the silicon film formed each time the silicon film passes through the film formation processing section 40 is 0.5nm or less. Therefore, by stacking silicon in a thickness of 1 atomic order to 2 atomic orders and hydrogenating the silicon in a thickness of 1 atomic order to 2 atomic orders, not only the surface of the silicon film but also the silicon atoms present in the film can be terminated with hydrogen, and the inside can be terminated with hydrogen uniformly in the thickness direction.

(6) The film formation apparatus 100 includes a chamber 20 in which a film formation processing section 40 and a hydrogenation processing section 50 are disposed in different areas, and the film formation processing section 40 and the hydrogenation processing section 50 are provided on a circumferential conveyance path L of the turntable 31. Thus, by continuing to move the workpiece 10 in one direction, the workpiece can be alternately conveyed to the film formation processing section 40 and the hydrogenation processing section 50 arranged on the conveying path L on the circumference of the turntable 31, and the film formation processing and the hydrogenation processing can be alternately repeated. Therefore, the film formation process and the hydrogenation process can be easily switched, and the balance between the film formation process time and the hydrogenation process time can be easily adjusted.

[ measurement of extinction coefficient ]

Fig. 5 shows the results of measurement of the extinction coefficients k of various silicon films included in the film forming apparatus, which are amorphous silicon films (α -Si films) formed by passing a workpiece alternately through the film forming section and the hydrogenation section, that is, hydrogenated silicon films, while the workpiece is being conveyed cyclically by the rotary table. Fig. 5 is a graph plotting the extinction coefficient k of the films formed under the conditions 1 to 8 of the hydrogen concentrations in the sputtering gas G1 and the process gas G2, respectively, with respect to the observation wavelength (400nm to 1200 nm). The extinction coefficient k is obtained by calculating the reflectance and transmittance measured by injecting the inspection light into the workpiece having the silicon film formed thereon and receiving the emitted light. The extinction coefficient k is a constant that represents how much light a medium absorbs when it has been injected into the medium. The larger the extinction coefficient k (plotted above in fig. 5), the higher the light absorption, and the smaller the extinction coefficient k, the higher the light transmittance. The dangling bonds of the formed silicon film tend to be terminated by hydrogen atoms, and the extinction coefficient k tends to be small. Therefore, by measuring the extinction coefficient k, it can be grasped whether or not hydrogen termination is performed satisfactorily.

(film Forming conditions)

The film formation conditions are as follows.

Workpiece: glass substrate

Target: si

The holder: stainless Steel (Steel Use Stainless, SUS)

Target-to-workpiece distance: 100mm (face-to-face state)

Rotation speed of the rotary table: 60rpm

Applied power to a high frequency of the antenna (hydrotreating section): 2000W

Direct current applied power to the sputter source: 1500W to 2500W (values of applied power to the respective sputtering sources in a film formation processing section including three sputtering sources)

Film formation rate: 0.2nm/s

Overall film thickness: 300nm

(gas Condition)

The conditions of the sputtering gas G1 and the process gas G2 are as follows.

< Condition 1 >

G1：Ar+H(0％)50sccm/G2：Ar+H(0％)200sccm

< Condition 2 >

G1：Ar+H(0％)50sccm/G2：Ar+H(3％)200sccm

< Condition 3 >

G1：Ar+H(0％)50sccm/G2：Ar+H(5％)200sccm

< Condition 4 >

G1：Ar+H(0％)50sccm/G2：Ar+H(7％)200sccm

< Condition 5 >

G1：Ar+H(0％)50sccm/G2：Ar+H(10％)200sccm

< Condition 6 >

G1：Ar+H(3％)50sccm/G2：Ar+H(3％)200sccm

< Condition 7 >

G1：Ar+H(5％)50sccm/G2：Ar+H(0％)200sccm

< Condition 8 >

G1：Ar+H(7％)50sccm/G2：Ar+H(0％)200sccm

[ results ]

Condition 1 is a condition where no hydrogen gas is added to any of sputtering gas G1 and process gas G2. Conditions 7 and 8 are conditions in which only hydrogen gas was added to sputtering gas G1. Condition 1 is the same as conditions 7 and 8 (result 1).

Conditions 2 to 5 are conditions in which hydrogen gas is added to the process gas G2. In conditions 2 to 5, a decrease in the extinction coefficient k was observed more significantly than in condition 1. In particular, the minimum extinction coefficient k is the condition 5 at wavelengths of 600nm or more. However, as in condition 6, when 3% of hydrogen gas was introduced into each of the process gas G2 and the sputtering gas G1, the extinction coefficient k was smaller at a wavelength of about 1000nm or more (wavelength range of infrared rays) than in conditions 2, 3, and 4 in which 3% or more of hydrogen gas was introduced (result 2).

As shown in result 1, it was found that the hydrogenation efficiency was poor even when only hydrogen gas was added to sputtering gas G1 as in conditions 7 and 8. As shown in result 2, it can be said that the reason why the extinction coefficient k becomes small in the conditions 2 to 5 is that hydrogenation is favorably performed. Further, it was found that by adding hydrogen gas to each of the process gas G2 and the sputtering gas G1 as in condition 6, hydrogenation can be efficiently performed without raising the hydrogen concentration to a concentration at which there is a risk of explosion.

As described above, by adding hydrogen gas to the process gas G2, a film having a small extinction coefficient k can be formed in the wavelength range of infrared rays. This makes it possible to apply the optical device to, for example, an optical product such as an infrared sensor that is required to absorb light in the visible light region and transmit light in the infrared region.

[ other embodiments ]

The embodiments and the modifications of the respective parts of the present invention have been described, but the embodiments and the modifications of the respective parts are presented as examples and are not intended to limit the scope of the present invention. The novel embodiments described above can be implemented in various other embodiments, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims.

For example, although the sputtering gas G1 and the process gas G2 are the same in the above embodiment, the rare gas and the hydrogen concentration may be different. Further, the sputtering gas G1 introduced by the sputtering gas introduction unit 49 may not contain hydrogen gas. That is, the hydrotreating may be performed only in the hydrotreating section 50. In this case, the hydrogen concentration of the process gas G2 may be the same as described above, but may be a high concentration at which the possibility of explosion is suppressed to a lower level in order to further improve the bonding efficiency. In addition, a plurality of hydrotreating portions 50 may be provided to improve the efficiency of hydrogenation.

The gas cylinders constituting the supply source 90 of the sputtering gas G1 and the process gas G2 are the gas cylinder 910 containing the rare gas and the gas cylinder 920 containing the hydrogen gas, but the present invention is not limited thereto. For example, the gas cylinder constituting the supply source 90 may be a gas cylinder containing a mixed gas of hydrogen gas and a rare gas at a predetermined ratio. In this case, the flow rate control meter 912A, the flow rate control meter 922A, the flow rate control meter 912B, and the flow rate control meter 922B, or the mixer 93A and the mixer 93B for mixing the rare gas and the hydrogen gas are omitted, and the mixed gas at a predetermined flow rate is introduced from the pipe 48 and the pipe 57 into the processing space 41 and the processing space 59 via the flow rate control meters. In addition, if the hydrogen concentrations of the sputtering gas G1 and the process gas G2 are the same, a common gas cylinder may be used.

For example, in the above embodiment, after the operation of the film formation processing section 40 is stopped in step S07, the operation of the hydrogenation processing section 50 is stopped in step S08, and the rotation of the rotary table 31 is stopped in step S09, but the present invention is not limited to this, and the conveying section 30, the film formation processing section 40, and the hydrogenation processing section 50 may be controlled so that the conveyance of the workpiece 10 is stopped by the hydrogenation processing section 50 that is operating at the end of the passage through the film formation processing section 40 and the hydrogenation processing section 50. In this case, for example, after the rotation of the rotary table 31 is stopped, the operation of the film formation processing section 40 and the operation of the hydrogenation section 50 may be stopped, and the conveyance of the workpiece 10 may be stopped by passing through the hydrogenation section 50. For example, since the film formation process is not performed in the film formation processing unit 40 that is not in operation, the conveyance of the workpiece 10 may be stopped after passing through the hydrogenation unit 50 and then through the film formation processing unit 40, as long as the operation of the film formation processing unit 40 is stopped.

For example, in the above-described embodiment, in order to stop the operation of the film formation processing section 40, that is, to stop the plasma generation operation, the introduction of the sputtering gas G1 is stopped and the voltage application by the power supply section 46 is stopped, but the present invention is not limited thereto, and at least one of the introduction of the sputtering gas G1 by the sputtering gas introduction section 49 and the voltage application by the power supply section 46 may be stopped. Similarly, in order to stop the operation of the hydrotreating section 50, that is, to stop the plasma generating operation, at least one of the introduction of the process gas G2 and the application of the voltage by the RF power source 54 may be stopped.

When a plurality of films are stacked, a film formation processing unit and a plasma processing unit may be further provided in the chamber 20. In this case, in addition to the film formation processing section 40, a film formation processing section using a target material of a different type from the target material may be added, or a film formation processing section using a target material of the same type may be added. Further, a plasma treatment unit using a process gas different from the hydrogenation treatment unit 50 may be added.