Film-forming apparatus

Abstract

Provided is a film forming apparatus that can efficiently generate highly reactive OH radicals or NH radicals required for forming a metal oxide film or a metal nitride film on an object in a reaction vessel by ALD, and can improve the film forming efficiency. The film forming apparatus (10) alternately introduces a metal compound gas and OH radicals or NH radicals into the reaction vessel (20) to form a metal oxide film or a metal nitride film by atomic layer deposition. The film forming apparatus (10) includes: a first gas source (40) that supplies oxygen or nitrogen; a second gas source (50) that supplies hydrogen; a third gas source (60) that supplies a carrier gas; a first pipe (32) that connects the first gas source and the third gas source to the reaction vessel; a first plasma generation unit (44) that generates a plasma containing oxygen radicals or nitrogen radicals dissociated from oxygen or nitrogen; a second pipe (52) that connects the second gas source and the third gas source to the reaction vessel; and a second plasma generation unit (54) that generates a plasma containing hydrogen radicals dissociated from hydrogen.

Description

Technical Field

[0001] The present invention relates to a film-forming apparatus for forming a metal oxide film or a metal nitride film on an object in a reaction vessel by ALD (atomic layer deposition) using OH radicals or NH radicals, and the like. Background Art

[0002] Using OH radicals, in Patent Documents 1 and 2, a resist is removed; in Patent Document 3, miscellaneous bacteria in water are killed; in Patent Document 4, a substance to be purified is decomposed for purification; in Patent Document 5, nitric acid is produced; in Patent Document 6, an organic binder or a protective agent is oxidized and decomposed from a conductive layer to improve conductivity; and in Patent Document 7, which is a patent of the present applicant, a metal oxide is formed on powder by ALD. In these Patent Documents 1 to 7, OH radicals are generated by plasma-exciting water vapor. In Patent Document 7, furthermore, a metal nitride film is formed using NH radicals. NH radicals are generated by plasma-exciting NH3.

[0003] In Patent Document 8, oxygen O2 and hydrogen H2 are plasma-excited in a processing chamber, whereby oxygen radicals required for forming an oxide film on a substrate by ALD are generated. Thus, compared with the case of using H2O or ozone O3, a moisture generator or an ozone generator is not required, and cost reduction is achieved.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-085231

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2008-109050

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 2012-096141

[0009] Patent Document 4: Japanese Patent Application Laid-Open No. 2013-086072

[0010] Patent Document 5: Japanese Patent Application Laid-Open No. 2016-150888

[0011] Patent Document 6: Japanese Patent Application Laid-Open No. 2020-113654

[0012] Patent Document 7: Japanese Patent No. 6787621

[0013] Patent Document 8: Japanese Patent No. 4694209 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] According to Patent Documents 1 to 7, a water generator is required to generate OH radicals, and when the water resistance of the object to be processed is poor, introducing water vapor may damage the surface of the object to be processed.

[0016] According to Patent Document 7, it is considered that in the process of decomposing NH3 by plasma to generate NH* (* represents a radical), the following states are mixed.

[0017] NH3 → NH* + 2H* → NH* + H2

[0018] NH3 → NH2 + H* → NH* + 2H* → NH* + H2

[0019] NH3 → N* + 3H* → NH* + 2H* → NH* + H2

[0020] Due to the mixing of such states, the generation efficiency of NH radicals is low.

[0021] According to Patent Document 8, in the process of generating oxygen radicals O* by thermal decomposition of oxygen O2 and hydrogen H2 at 500°C to 600°C, the following thermal reactions occurred (refer to Paragraph 0032).

[0022] H2 + O2 → H* + HO2

[0023] O2 + H* → OH* + O*

[0024] H2 + O* → H* + OH*

[0025] H2 + OH* → H* + H2O

[0026] Here, although Patent Document 8 is not aimed at generating OH* (OH radicals), if oxygen O2 and hydrogen H2 are thermally excited, as a result, OH* (OH radicals) will be generated. However, due to the mixing of the above states, the generation efficiency of OH radicals is low. Furthermore, because in the processing chamber of Patent Document 8, there are also reactions that transfer to the following stable systems due to collisions between O and O, H and H, etc.

[0027] O + O → O2

[0028] H + H → H2

[0029] O + OH → O2H

[0030] H + OH → H2O

[0031] The present invention provides a film forming apparatus that can efficiently generate highly reactive OH radicals or NH radicals required for forming a metal oxide film or a metal nitride film on an object in a reaction vessel by ALD, and can improve the film forming efficiency.

[0032] Means for Solving the Problem

[0033] (1) The present invention relates to a film forming apparatus that alternately introduces a metal compound gas and OH radicals or NH radicals into a reaction vessel, and forms a metal oxide film or a metal nitride film by atomic layer deposition.

[0034] The film forming apparatus includes:

[0035] A first gas source that supplies oxygen or nitrogen;

[0036] A second gas source that supplies hydrogen;

[0037] A third gas source that supplies a carrier gas;

[0038] A first pipe that connects the first gas source and the third gas source to the reaction vessel;

[0039] A first plasma generation unit that is provided in the first pipe and generates a plasma containing oxygen radicals or nitrogen radicals dissociated from the oxygen or the nitrogen;

[0040] A second pipe that connects the second gas source and the third gas source to the reaction vessel; and

[0041] A second plasma generation unit that is provided in the second pipe and generates a plasma containing hydrogen radicals dissociated from the hydrogen,

[0042] The converged oxygen radicals and the hydrogen radicals are collided to generate the OH radicals, or the nitrogen radicals and the hydrogen radicals are collided to generate the NH radicals.

[0043] According to one aspect of the present invention, in the metal compound gas adsorbed on an object in the reaction vessel, organic substances or inorganic substances other than the metal component are dissociated by the OH radicals and oxidized by the OH groups to become metal oxides. Alternatively, in the metal compound gas adsorbed on an object in the reaction vessel, organic substances or inorganic substances other than the metal component are dissociated by the NH radicals and nitrided by the NH groups to become metal nitrides. The metal oxides or metal nitrides are sequentially deposited at the atomic layer level to form a metal oxide film or a metal nitride film on the object.

[0044] Here, for example, if the carrier gas is argon Ar, in the first plasma generation unit provided in the first pipe, oxygen radicals O* or nitrogen radicals N* dissociated from oxygen molecules or nitrogen molecules are generated as shown in the following (1) or (2). It should be noted that electrons and ions are ionized in the plasma, but most of them are inactivated in the pipe downstream of the plasma generation unit, and it is considered that only oxygen radicals and nitrogen radicals protected by the carrier gas Ar remain.

[0045] O2 + Ar → 2O* + Ar…(1)

[0046] N2 + Ar → 2N* + Ar…(2)

[0047] On the other hand, in the second plasma generation unit provided in the second pipe, as shown in the following (3), hydrogen radicals H* dissociated from hydrogen molecules are generated. In this case, electrons and ions in the plasma are also deactivated, and it is considered that only hydrogen radicals protected by the carrier gas Ar remain.

[0048] H2 + Ar → 2H* + Ar…(3)

[0049] In the reaction vessel connected to the first pipe and the second pipe, oxygen radicals O* or nitrogen radicals N* are introduced together with the carrier gas through the first pipe, and hydrogen radicals H* are introduced together with the carrier gas through the second pipe. In this way, the converging oxygen radicals O* or nitrogen radicals N* collide with the hydrogen radicals H*, and OH radicals or NH radicals are generated through the reactions shown in the following (4) or (5).

[0050] O* + H* + Ar → OH* + Ar…(4)

[0051] N* + H* + Ar → NH* + Ar…(5)

[0052] That is, in (4), mainly, the oxygen radicals O* and hydrogen radicals H* protected by the carrier gas are respectively introduced into the reaction vessel, and they first collide / associate with each other in the reaction vessel to generate OH radicals. Therefore, compared with the generation process in Patent Document 8 in which OH radicals are generated by thermally exciting oxygen O2 and hydrogen H2 simultaneously in the processing vessel, the present invention can generate OH radicals more efficiently. Similarly, in (5), mainly, the nitrogen radicals N* combine with the hydrogen radicals H* to generate NH radicals. Therefore, compared with the generation process in Patent Document 7 in which NH radicals are generated by exciting NH3, the present invention can generate NH radicals more efficiently.

[0053] (2) In one aspect (1) of the present invention, at least one of the first pipe and the second pipe includes a first charged particle removing portion, and the first charged particle removing portion can remove charged particles composed of ionized ions and / or electrons in the plasma in the first plasma generating portion and the second plasma generating portion by using the charges of the charged particles. Thus, for cations with positive charges, anions with negative charges, electrons, etc., excessive or insufficient electrons are released / implanted from the metal pipe and neutralized. In this way, charged particles such as cations, anions, and electrons generated in the first plasma generating portion and the second plasma generating portion are removed by using the charges they possess. As a result, mainly oxygen radicals or nitrogen radicals and hydrogen radicals are supplied to the reaction vessel. Thereby, OH radicals or NH radicals are generated more efficiently in the reaction vessel.

[0054] (3) In one aspect (1) of the present invention, the first pipe and the second pipe can be connected to the reaction vessel through a converging pipe. In this way, the reaction of the above formula (4) or (5) can be carried out more efficiently in the converging pipe which can be designed to have a volume sufficiently small compared to the reaction vessel, and the OH radicals or NH radicals generated in the converging pipe can be supplied into the reaction vessel.

[0055] (4) In one aspect (2) of the present invention, the first pipe and the second pipe can also be connected to the reaction vessel through a converging pipe. In this way, the same effects as in one aspect (1) to (3) of the present invention are obtained.

[0056] (5) In one aspect (3) or (4) of the present invention, the converging pipe also includes a second charged particle removing portion, and the second charged particle removing portion can remove charged particles composed of ionized ions and / or electrons in the plasma in the first plasma generating portion and the second plasma generating portion by using the charges of the charged particles. In this way, the same effects as in one aspect (1), (2), and (4) of the present invention are obtained. That is, charged particles such as cations, anions, and electrons generated in the first plasma generating portion and the second plasma generating portion are removed by using the charges they possess. As a result, mainly oxygen radicals or nitrogen radicals and hydrogen radicals are supplied to the converging pipe. In addition, cations, anions, and electrons remaining in the converging pipe are also removed by using the charges they possess. Thereby, OH radicals or NH radicals are supplied to the reaction vessel more efficiently.

[0057] (6) In one of the embodiments (1) or (2) of the present invention, the first pipe has a first valve between the first plasma generation unit and the reaction vessel, and the second pipe has a second valve between the second plasma generation unit and the reaction vessel. During the period when one of the first valve and the second valve is open, the other of the first valve and the second valve can be closed. In this way, when the first valve is open, the oxygen radicals or nitrogen radicals generated in the first plasma generation unit are supplied to the reaction vessel. At this time, since the second valve is closed, the oxygen radicals or nitrogen radicals do not flow into the second plasma generation unit. Before or after this, when the second valve is open, the hydrogen radicals generated in the second plasma generation unit are supplied to the reaction vessel. At this time, the first valve is closed, so the hydrogen radicals do not flow into the first plasma generation unit.

[0058] (7) Another embodiment of the present invention relates to a film forming apparatus that alternately introduces a metal compound gas and OH radicals or NH radicals into a reaction vessel to form a metal oxide film or a metal nitride film by atomic layer deposition.

[0059] The film forming apparatus includes:

[0060] A first gas source that supplies oxygen or nitrogen;

[0061] A second gas source that supplies hydrogen;

[0062] A third gas source that supplies a carrier gas;

[0063] A first pipe that is connected to the first gas source and the third gas source;

[0064] A second pipe that is connected to the second gas source and the third gas source;

[0065] A converging pipe, one end of which is connected to the first pipe and the second pipe, and the other end of which is connected to the reaction vessel; and

[0066] A plasma generation unit that is provided in the converging pipe and generates a plasma containing radicals dissociated from the gas introduced into the converging pipe.

[0067] The first pipe has a first valve upstream of the plasma generation unit.

[0068] The second pipe has a second valve upstream of the plasma generation unit.

[0069] When the first valve is open and the second valve is closed, the plasma generation unit generates a plasma containing oxygen radicals or nitrogen radicals dissociated from the oxygen or the nitrogen.

[0070] When the second valve is open and the first valve is closed, the plasma generation unit generates a plasma containing hydrogen radicals dissociated from the hydrogen.

[0071] In the reaction vessel, the oxygen radicals and the hydrogen radicals collide to generate the OH radicals, or the nitrogen radicals and the hydrogen radicals collide to generate the NH radicals.

[0072] In this way, when the first valve is open and the second valve is closed, the oxygen radicals or nitrogen radicals generated in one plasma generation unit are supplied to the reaction vessel. Before or after that, when the second valve is open and the first valve is closed, the hydrogen radicals generated in one plasma generation unit are supplied to the reaction vessel.

[0073] (8) In one embodiment (7) of the present invention, the converging pipe also includes a charged particle removing unit, and the charged particle removing unit removes charged particles composed of ionized ions and / or electrons in the plasma in the plasma generation unit by using the charges of the charged particles. In this way, the same effect as that of one embodiment (5) of the present invention is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 FIGS. are diagrams showing the first embodiment and the second embodiment of the film forming apparatus of the present invention.

[0075] Figure 2 FIG. is a timing chart showing the switching operations of various valves in the first embodiment.

[0076] Figure 3 FIG. is a timing chart showing one cycle of ALD implemented in the first embodiment.

[0077] Figure 4 FIG. is a timing chart showing the switching operations of various valves in the second embodiment.

[0078] Figure 5 FIG. is a timing chart showing one cycle of ALD implemented in the second embodiment.

[0079] Figure 6 FIG. is a diagram showing the third embodiment of the film forming apparatus of the present invention.

[0080] Figure 7 FIG. is a diagram showing the fourth embodiment of the film forming apparatus of the present invention.

[0081] Figure 8 FIG. is a timing chart showing the switching operations of various valves in the fourth embodiment.

[0082] Figure 9 FIG. is a diagram showing a structure for removing cations, anions, etc. by using their charges in the middle of the pipe. Detailed implementation manners

[0083] In the following disclosure, different implementation manners and embodiments are provided to implement different features of the presented subject matter. Of course, these are merely examples and are not meant to be limiting. In addition, in this disclosure, reference numerals and / or words are sometimes repeated in various examples. The purpose of this repetition is to be concise and clear and does not require a relationship between itself and various implementation manners and / or the described configurations. Further, when the first element is described as "connected" or "coupled" to the second element, such description includes embodiments where the first element and the second element are directly connected or coupled to each other, and also includes embodiments where the first element and the second element are indirectly connected or coupled to each other with one or more other elements therebetween. Additionally, when the first element is described as "moving" relative to the second element, such description includes embodiments of relative movement where at least one of the first element and the second element moves relative to the other.

[0084] 1. First implementation manner

[0085] 1.1. ALD device

[0086] Figure 1 An example of the ALD device 10 is shown. The ALD device 10 includes a reaction vessel 20 and various gas sources 30 to 60. The reaction vessel 20 is a vessel for forming a film on a workpiece (object to be processed) 1. The reaction vessel 20 can have a placement portion 21 that places, for example, a substrate as the object to be processed 1. When the object to be processed is a powder or the like, it is only necessary to hold the powder in a dispersed state within the reaction vessel 20. The reaction vessel 20 is connected to various gas sources 30 to 60, and various gases are introduced into the reaction vessel 20. An exhaust pipe 70 is connected to the reaction vessel 20, and the inside of the reaction vessel 20 can be evacuated by an exhaust pump 71.

[0087] The source gas supply 30 supplies a metal compound gas, such as an organometallic gas, as the source gas selected according to the film deposited on the object to be processed 1. The source gas supply 30 and the reaction vessel 20 are connected by a pipe 33 having a flow controller (MFC) 31 and a valve 32. For the source gas, it is supplied into the reaction vessel 20 from the source gas supply 30 via the pipe 33 having the flow controller 31 and the valve 32 while controlling the supply time and flow rate.

[0088] The oxygen / nitrogen source 40 and the hydrogen source 50 are reaction gas sources. For the oxygen / nitrogen source (the first gas source) 40, oxygen is contained when forming an oxide film, and nitrogen is contained when forming a nitride film. The oxygen / nitrogen source 40 and the reaction vessel 20 are connected by a pipe 43 equipped with a mass flow controller (MFC) 41, a valve 42, and a first plasma generation unit 44. It should be noted that the valve 47 provided in the pipe 43 is optional in the first embodiment, and if it is provided, it is always fully open. The hydrogen source 50 and the reaction vessel 20 are connected by a pipe 53 equipped with a mass flow controller (MFC) 51, a valve 52, and a second plasma generation unit 54. It should be noted that the valve 57 provided in the pipe 53 is optional in the first embodiment, and if it is provided, it is always fully open.

[0089] The carrier gas source 60 contains an inert gas, such as argon Ar. In this embodiment, in addition to the carrier gas, the argon Ar in the carrier gas source 60 is also used as a purge gas. Therefore, the carrier gas source 60 and the reaction vessel 20 can be connected by a pipe 63 equipped with a mass flow controller (MFC) 61, a valve 62, and a valve 66. In this way, argon Ar is supplied into the reaction vessel 20 as a purge gas via the pipe 63 while controlling the supply time and flow rate. Thereby, the atmosphere in the reaction vessel 20 can be replaced with argon gas Ar. The pipe 63 has first to third branch pipes 63A to 63C downstream of the valve 62. The first branch pipe 63A is connected to the pipe 33 through a valve 64. The second branch pipe 63B is connected to the pipe 43 through a valve 65. The third branch pipe 63C is connected to the pipe 53 through a valve 66. In this way, argon Ar can be used as a carrier gas for the source gas and oxygen or nitrogen, or hydrogen.

[0090] The first plasma generation unit 44 has an induction coil 46 around a non-metal pipe 45, such as a quartz pipe, as an excitation unit for oxygen or nitrogen. A high-frequency power source (not shown) is connected to the induction coil 46. For example, the electromagnetic energy applied by the induction coil 46 is 20 W, and the frequency is 13.56 MHz. An inductively coupled plasma P1 of the gas is generated in the first plasma generation unit 44 by the induction coil 46. This plasma P1 contains oxygen radicals or nitrogen radicals dissociated from oxygen molecules or nitrogen molecules.

[0091] Similarly, the second plasma generation unit 54 has an induction coil 56 around a non-metal, such as a quartz pipe 55, as an excitation unit for hydrogen. An inductively coupled plasma P2 of the gas is generated in the second plasma generation unit 54 by the induction coil 56. This plasma P2 contains hydrogen radicals dissociated from hydrogen molecules.

[0092] 1.2. ALD method

[0093] An example of forming a metal oxide film, such as an Al2O3 film, on the object to be processed 1 will be described. Since the oxygen / nitrogen source 40 contains oxygen, it will also be referred to as the oxygen source 40 hereinafter. First, the object to be processed 1 is transported into the reaction vessel 20. In the first embodiment, according to Figure 2 the timing diagram shown Figure 1 various valves shown, whereby Figure 3 the ALD cycle shown is implemented. The ALD cycle refers to a cycle with at least four steps of input of the first precursor (feed gas) → exhaust (including purge) → input of the second precursor (reactive gas) → exhaust (including purge). It should be noted that the exhaust is vacuum exhaust using the exhaust pump 71, and the purge refers to supplying an inert gas (purge gas) from the carrier gas source 60. In either case, the inside of the reaction vessel 20 is replaced from the atmosphere of the first precursor or the second precursor to a vacuum or purge gas atmosphere. The film thickness of the film formed on the object to be processed 1 is proportional to the number of ALD cycles N. Thus, the ALD cycle is repeatedly implemented the required number of times N.

[0094] 1.2.1. Supply of Feed Gas

[0095] First, the inside of the reaction vessel 20 is evacuated using the exhaust pump 71, for example, set to 10 -4 Pa. Next, as Figure 2 shown, valves 32, 62, and 64 are opened during period T1. In this way, the feed gas (e.g., TMA (Al(CH3)3)) from the feed gas source 30 and the carrier gas (e.g., argon Ar) from the carrier gas source 60 are supplied to the reaction vessel 20 and filled at a specific pressure (e.g., 1 Pa to 10 Pa). In Figure 3 the first step (period T1) of the ALD cycle shown, TMA penetrates into the exposed surface of the object to be processed 1.

[0096] 1.2.2. Purge

[0097] After that, as the second step of the ALD cycle, as Figure 2 shown, valves 32 and 64 are closed, valve 62 is maintained open, and valve 67 is opened during period T2. Thus, as Figure 3 shown, the purge gas is introduced into the reaction vessel 20, and the trimethylaluminum Al(CH3)3 in the reaction vessel 20 is replaced with the purge gas.

[0098] 1.2.3. Introduction of Reactive Gas

[0099] Next, as the third step of the ALD cycle, as Figure 2As shown, valve 67 is closed, valve 62 is maintained open, and valves 42, 52, 65, and 66 are open during period Т3. In this way, oxygen from oxygen source 40 and carrier gas argon Ar from carrier gas source 60 are supplied to the first plasma generation unit 44. At the same time, hydrogen from hydrogen source 50 and carrier gas argon Ar from carrier gas source 60 are supplied to the second plasma generation unit 54. In the first plasma generation unit 44, an inductively coupled plasma P1 containing oxygen radicals dissociated from oxygen as shown in the above formula (1) is generated. The oxygen radicals are supplied to the reaction vessel 20 together with the carrier gas through pipe 43. On the other hand, in the second plasma generation unit 54, an inductively coupled plasma P2 containing hydrogen radicals dissociated from hydrogen as shown in the above formula (3) is generated. The hydrogen radicals are supplied to the reaction vessel 20 together with the carrier gas through pipe 53 along a path different from that of the oxygen radicals.

[0100] In the reaction vessel 20, the oxygen radicals and hydrogen radicals are first converged. As a result, in the reaction vessel 20, as shown in the above formula (4), OH radicals formed by the collision / combination of oxygen radicals and hydrogen radicals are generated. The OH radicals (OH*) as the reaction gas are filled in the reaction vessel 20 at a specific pressure (for example, 1 Pa to 10 Pa) ( Figure 3 during period Т3), and the OH radicals (OH*) penetrate into the exposed surface of the workpiece 1. As a result, on the exposed surface of the workpiece 1, the organic matter CH3 dissociates from ТMA (Al(CH3)3), and at the same time, the metal Al is oxidized, thereby generating aluminum oxide Al2O3. Thus, the exposed surface of the workpiece 1 is coated with a metal oxide film. In particular, even at room temperature, the organometallic gas can be saturated and adsorbed on the hydroxyl groups (-OH) on the exposed surface of the workpiece 1. Therefore, it is not necessary to forcibly heat the workpiece 1 during film formation.

[0101] 1.2.4. Purge

[0102] After that, as the fourth step of the ALD cycle, as Figure 2 shown, valves 42, 52, 65, and 66 are closed, valve 62 is maintained open, and valve 67 is open during period Т4. As a result, a purge gas is introduced into the reaction vessel 20, and the reaction gas in the reaction vessel 20 is replaced with the purge gas. The Al2O3 film can be formed at about 1 angstrom = 0.1 nm per cycle. Therefore, for example, to form a film thickness of 10 nm, 100 ALD cycles (Т) are repeated. After all the ALD cycles are completed, the workpiece 1 is taken out of the reaction vessel 20.

[0103] 2. Second Embodiment

[0104] Regarding the second embodiment, in the Figure 1 ALD apparatus 10, according to the Figure 4 timing diagram shown, the switchFigure 1 the various valves shown, thereby implementing Figure 5 the ALD cycle shown. Different from the first embodiment, in the second embodiment, the valve 47 functioning as the first valve and the valve 57 functioning as the second valve are opened and closed.

[0105] 2.1. Supply of source gas

[0106] As Figure 4 shown, the valves 32, 62, and 64 are opened during period T1. In this way, for example, argon Ar from the carrier gas source 60 is used as the carrier gas, and the source gas (e.g., TMA (Al(CH3)3)) from the source gas source 30 is supplied to the reaction vessel 20 and filled at a specific pressure (e.g., 1 Pa to 10 Pa). In Figure 5 the first step (period T1) of the ALD cycle shown, TMA penetrates into the exposed surface of the object to be processed 1.

[0107] 2.2. Purge

[0108] After that, as the second step of the ALD cycle, as Figure 4 shown, the valves 32 and 64 are closed, the valve 62 is maintained open, and the valve 67 is opened during period T2. As a result, as Figure 5 shown, the purge gas is introduced into the reaction vessel 20, and the trimethylaluminum Al(CH3)3 in the reaction vessel 20 is replaced with the purge gas.

[0109] 2.3. Introduction of reaction gas

[0110] Next, as the third step of the ALD cycle, as Figure 4 shown, the valve 67 is closed, the valve 62 is maintained open, and the valves 42, 47, and 65 are opened during period T3. In this way, argon Ar from the carrier gas source 60 is used as the carrier gas, and oxygen from the oxygen source 40 is supplied to the first plasma generation unit 44. In the first plasma generation unit 44, an inductively coupled plasma P1 containing oxygen radicals dissociated from oxygen as shown in the above formula (1) is generated. The oxygen radicals are supplied to the reaction vessel 20 together with the carrier gas through the pipe 43. In this way, the oxygen radicals fill the reaction vessel 20 at a specific pressure. At this time, since the second valve 57 is closed, the oxygen radicals do not flow into the second plasma generation unit 54.

[0111] Next, as Figure 4As shown, valves 42, 47, and 65 are closed, and valves 52, 57, and 66 are open during period Т4. In this way, argon Ar from the carrier gas source 60 is used as the carrier gas, and hydrogen from the hydrogen source 50 is supplied to the second plasma generation unit 54. In the second plasma generation unit 54, an inductively coupled plasma P2 containing hydrogen radicals dissociated from hydrogen as shown in the above formula (3) is generated. The hydrogen radicals are supplied to the reaction vessel 20 through the pipe 53 together with the carrier gas through a path different from that of the oxygen radicals. In this way, the hydrogen radicals fill the reaction vessel 20 at a specific pressure. At this time, the first valve 47 is closed, so the hydrogen radicals do not flow into the first plasma generation unit 44.

[0112] In the reaction vessel 20, the oxygen radicals and the hydrogen radicals are first converged. As a result, in the reaction vessel 20, as shown in the above formula (4), OH radicals formed by the collision / combination of the oxygen radicals and the hydrogen radicals are generated. The OH radicals (OH*) as the reaction gas are filled in the reaction vessel 20 at a specific pressure (for example, 1 Pa to 10 Pa) ( Figure 5 during period Т4), and the OH radicals (OH*) penetrate into the exposed surface of the workpiece 1. As a result, aluminum oxide Al2O3 is generated on the exposed surface of the workpiece 1 in the same manner as in the first embodiment.

[0113] 2.4. Purge

[0114] After that, as the fourth step of the ALD cycle, as Figure 4 shown, valves 52, 57, and 66 are closed, the opening of valve 62 is maintained, and valve 67 is open during period Т5. As a result, a purge gas is introduced into the reaction vessel 20, and the reaction gas in the reaction vessel 20 is replaced with the purge gas.

[0115] 3. Third Embodiment

[0116] 3.1. ALD Apparatus

[0117] Figure 6 An example of the ALD apparatus 11 is shown. In the ALD apparatus 11, components having the same functions as those of the components of the ALD apparatus 10 shown in Figure 1 are attached with the same reference numerals as Figure 1 shown, and their descriptions are omitted. In the ALD apparatus 11, the first pipe 43 and the second pipe 53 are connected to the reaction vessel 20 through a converging pipe 80.

[0118] 3.2. ALD Method

[0119] Regarding the third embodiment, in the Figure 6 ALD apparatus 11, various valves shown in Figure 2 are switched according to the timing chart shown in Figure 6 to implement Figure 3The ALD cycle shown herein. Here, the ALD method in the third embodiment differs only in the introduction of the reaction gas during period T3 (the third step) from that in the first embodiment. Therefore, the operation during period T3 will be described below.

[0120] As the third step of the ALD cycle, as Figure 2 shown, valve 67 is closed, valve 62 is maintained open, and valves 42, 52, 65, and 66 are open during period T3. In this way, oxygen from the oxygen source 40 and carrier gas argon Ar from the carrier gas source 60 are supplied to the first plasma generation unit 44. At the same time, hydrogen from the hydrogen source 50 and carrier gas argon Ar from the carrier gas source 60 are supplied to the second plasma generation unit 54. In the first plasma generation unit 44, an inductively coupled plasma P1 containing oxygen radicals dissociated from oxygen as shown in the above formula (1) is generated. The oxygen radicals are supplied to the confluence pipe 80 through the pipe 43 together with the carrier gas. On the other hand, in the second plasma generation unit 54, an inductively coupled plasma P2 containing hydrogen radicals dissociated from hydrogen as shown in the above formula (3) is generated. The hydrogen radicals are supplied to the confluence pipe 80 through the pipe 53 together with the carrier gas.

[0121] In the confluence pipe 80, the oxygen radicals and hydrogen radicals are first confluent. As a result, OH radicals formed by the collision / combination of oxygen radicals and hydrogen radicals are generated in the confluence pipe 80 as shown in the above formula (4). The OH radicals (OH*) as the reaction gas are supplied from the confluence pipe 80 to the reaction vessel 20 and filled in the reaction vessel 20 at a specific pressure (for example, 1 Pa to 10 Pa). The OH radicals (OH*) penetrate the exposed surface of the object to be processed 1. As a result, similar to the first embodiment, the exposed surface of the object to be processed 1 is coated with a metal oxide film.

[0122] 4. Fourth Embodiment

[0123] 4.1. ALD Apparatus

[0124] Figure 7 An example of the ALD apparatus 12 is shown. In the ALD apparatus 12, components having the same functions as those of the ALD apparatus 10 shown Figure 1 are attached with the same reference numerals as Figure 1 and their description is omitted. In the ALD apparatus 12, the first pipe 43 and the second pipe 53 are connected to the reaction vessel 20 through a confluence pipe 90. And a plasma generation unit 94 is provided in the confluence pipe 90. The confluence pipe 90 is connected to a branch pipe 63D branched from the carrier gas pipe 63 through a valve 68. In this fourth embodiment, the valves 42 and 68 upstream of the plasma generation unit 94 function as the first valve, and another valve 52 upstream of the plasma generation unit 94 functions as the second valve.

[0125] 4.2. ALD Method

[0126] Regarding the fourth embodiment, in the ALD apparatus 12 of Figure 7 , the various valves shown in Figure 8 are switched according to the timing chart shown in Figure 7 , thereby implementing the ALD cycle shown in Figure 5 . Here, the ALD method in the fourth embodiment is different from that in the second embodiment only in the introduction of the reaction gas (the third step) during T3 to T4. Therefore, the operations during T3 to T4 will be described below.

[0127] Figure 8 , the valve operations during T1, T2, and T5 are the same as those in Figure 4 . As the third step (during T3 and T4) of the ALD cycle, first, as shown in Figure 8 , valve 67 is closed, valve 62 is maintained open, and valves 42 and 68 are open during T3. In this way, oxygen from the oxygen source 40 and carrier gas argon Ar from the carrier gas source 60 are supplied to the plasma generation unit 94. In the plasma generation unit 94, inductively coupled plasma P containing oxygen radicals dissociated from oxygen as shown in the above formula (1) is generated. The oxygen radicals and the carrier gas are supplied to the reaction vessel 20 through the confluence pipe 90. In this way, the oxygen radicals fill the inside of the reaction vessel 20 at a specific pressure.

[0128] Next, as shown in Figure 8 , valve 42 is closed, valve 62 is maintained open, and valves 52 and 68 are open during T4. In this way, hydrogen from the hydrogen source 50 and carrier gas argon Ar from the carrier gas source 60 are supplied to the plasma generation unit 94. In the plasma generation unit 94, inductively coupled plasma P containing hydrogen radicals dissociated from hydrogen as shown in the above formula (3) is generated. The hydrogen radicals and the carrier gas are supplied to the reaction vessel 20 through the confluence pipe 90. In this way, the hydrogen radicals fill the inside of the reaction vessel 20 at a specific pressure.

[0129] In the reaction vessel 20, the oxygen radicals and hydrogen radicals are first converged. As a result, OH radicals generated by the collision / combination of oxygen radicals and hydrogen radicals as shown in the above formula (4) are generated inside the reaction vessel 20. The OH radicals (OH*) as the reaction gas are filled in the reaction vessel 20 at a specific pressure (for example, 1 Pa to 10 Pa) during Figure 8 T4 of

[0130] 5. Modification Example

[0131] If nitrogen is used instead of oxygen, which is the reaction gas used for forming a metal oxide film, a metal nitride film can be formed. In this case, Figure 1 an oxygen / nitrogen source 40 such as Figure 1 contains nitrogen. In this way, NH radicals can be efficiently generated using nitrogen radicals (N*) and hydrogen radicals (H*). If, for example, TDMAS (SiH[N(CH3)2]3) is used as the source gas, SiN can be formed on the surface of the object to be processed 1. If, for example, TDMAT (Ti[N(CH3)2]4) is used as the source gas, TiN can be formed on the surface of the object to be processed 1. In either case, due to the presence of NH radicals, a low-temperature process can be achieved.

[0132] The source gas is not limited to the above-mentioned organometallic compounds and can also be an inorganic metal compound. For example, if the inorganic metal compound gas SiCl4 is supplied to the surface of the substrate 1, SiCl2 is adsorbed by SiCl4, and Cl2 is desorbed and discharged.

[0133] SiCl4 → SiCl2 + Cl2↑

[0134] If OH radicals are supplied in this state, SiCl2 is oxidized to form SiO2, and HCl is desorbed and discharged.

[0135] SiCl2 + OH → SiO2 + 2HCl↑

[0136] In addition, TiCl4 and SiH2Cl2, which are other inorganic metal compound gases, can also form metal oxide films in the same way.

[0137] On the downstream side of the first plasma generation unit and the second plasma generation units 44 and 54 or the plasma generation unit 94, oxygen radicals, hydrogen radicals, or OH radicals are supplied to the reaction vessel 20 through Figure 1 the pipes 43 and 53, Figure 6 the converging pipe 80, or Figure 7 the converging pipe 90, which, for example, includes Figure 9 the metal pipe 100 shown in Figure 9 . For example, an AC power supply 101 that applies an AC voltage that varies from -100V to +100V at 10Hz to 100Hz can be connected to the metal pipe 100. In particular, it is preferably Figure 9A metal bending pipe 102 is provided for the metal pipe 100. In this way, when a negative voltage is applied to the metal pipe 100, positively charged cations and the like, and when a positive voltage is applied to the metal pipe 100, negatively charged anions and other charged particles are respectively adsorbed to the pipe 100, and excess or insufficient electrons are emitted / injected from the metal pipe and neutralized. In this way, cations, anions, electrons, etc. are removed by the charges they possess. As a result, in Embodiments 1 and 2, mainly oxygen radicals or nitrogen radicals and hydrogen radicals are supplied to the reaction vessel 20. In Embodiment 3, mainly oxygen radicals or nitrogen radicals and hydrogen radicals are supplied to the converging pipe 80, and further, mainly OH radicals or NH radicals are supplied to the reaction vessel 20. In Embodiment 4, mainly oxygen radicals or nitrogen radicals and hydrogen radicals are supplied to the converging pipe 90, and further, mainly OH radicals or NH radicals are supplied to the reaction vessel 20. The charged particle removing portion may be provided with the metal pipe 100. Alternatively, the charged particle removing portion may be provided with a net formed of charge adsorption fibers in the middle of the pipe. The charge adsorption fibers may be grounded, or may be connected to an AC power source.

[0138] Symbol Description

[0139] 1... Object to be processed, 10 - 12... ALD apparatus, 20... Reaction vessel, 30... Source of raw material gas, 31, 41, 51, 61... Flow controller, 32, 42, 52, 62, 64, 66 - 68... Valve, 33... Pipe, 40... Oxygen / nitrogen source (first gas source), 42... First valve, 43, 63, 63A... First pipe, 44... First plasma generation unit, 47... First valve, 50... Hydrogen source (second gas source), 52... Second valve, 53, 63, 63B... Second pipe, 54... Second plasma generation unit, 57... Second valve, 60... Carrier gas source (third gas source), 70... Exhaust pipe, 71... Exhaust pump, 80, 90... Converging pipe, 94... Plasma generation unit, 100 - 102... Charged particle removing portion, 100... Metal pipe, 101... AC power source, 102... Bending pipe.

Claims

1. A film forming apparatus that alternately introduces a metal compound gas and OH radicals or NH radicals into a reaction vessel and forms a metal oxide film or a metal nitride film by atomic layer deposition. The film forming apparatus includes: A first gas source that supplies oxygen or nitrogen; A second gas source that supplies hydrogen; A third gas source that supplies a carrier gas; A first pipe that connects the first gas source and the third gas source to the reaction vessel; A first plasma generation unit that is provided in the first pipe and generates a plasma containing oxygen radicals or nitrogen radicals dissociated from the oxygen or the nitrogen; A second pipe that connects the second gas source and the third gas source to the reaction vessel; and A second plasma generation unit that is provided in the second pipe and generates a plasma containing hydrogen radicals dissociated from the hydrogen, causing the oxygen radicals to collide with the hydrogen radicals to generate the OH radicals, or causing the nitrogen radicals to collide with the hydrogen radicals to generate the NH radicals.

2. The film forming apparatus according to claim 1, wherein, At least one of the first pipe and the second pipe includes a first charged particle removing unit that removes charged particles composed of ionized ions and / or electrons in the plasma in the first plasma generation unit and the second plasma generation unit by using the charge of the charged particles.

3. The film forming apparatus according to claim 1, wherein, The first pipe and the second pipe are connected to the reaction vessel through a converging pipe.

4. The film forming apparatus according to claim 2, wherein, The first pipe and the second pipe are connected to the reaction vessel through a converging pipe.

5. The film forming apparatus according to claim 3 or 4, wherein, The converging pipe includes a second charged particle removing unit that removes charged particles composed of ionized ions and / or electrons in the plasma in the first plasma generation unit and the second plasma generation unit by using the charge of the charged particles.

6. The film forming apparatus according to claim 1 or 2, wherein, The first pipe has a first valve between the first plasma generation unit and the reaction vessel. The second pipe has a second valve between the second plasma generation unit and the reaction vessel. During the period when one of the first valve and the second valve is open, the other of the first valve and the second valve is closed.

7. A film forming apparatus that alternately introduces a metal compound gas and OH radicals or NH radicals into a reaction vessel and forms a metal oxide film or a metal nitride film by atomic layer deposition. The film forming apparatus has: A first gas source that supplies oxygen or nitrogen; A second gas source that supplies hydrogen; A third gas source that supplies a carrier gas; A first pipe that is connected to the first gas source and the third gas source; A second pipe that is connected to the second gas source and the third gas source; A converging pipe that has one end connected to the first pipe and the second pipe and the other end connected to the reaction vessel; and A plasma generation unit that is provided in the converging pipe and generates a plasma containing radicals dissociated from the gas introduced into the converging pipe, The first pipe has a first valve upstream of the plasma generation unit. The second pipe has a second valve upstream of the plasma generation unit. When the first valve is open and the second valve is closed, the plasma generation unit generates a plasma containing oxygen radicals or nitrogen radicals dissociated from the oxygen or the nitrogen. When the second valve is open and the first valve is closed, the plasma generation unit generates a plasma containing hydrogen radicals dissociated from the hydrogen. In the reaction vessel, the oxygen radicals collide with the hydrogen radicals to generate the OH radicals, or the nitrogen radicals collide with the hydrogen radicals to generate the NH radicals.

8. The film forming apparatus according to claim 7, wherein, The converging pipe includes a charged particle removing unit that removes charged particles composed of ionized ions and / or electrons in the plasma in the plasma generation unit by using the charges of the charged particles.

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