Film forming method and film forming apparatus

Abstract

To provide a film deposition method and a film deposition apparatus capable of surely performing a film deposition process.SOLUTION: A film deposition method alternatively performs a first process P1 that includes at least a first sequence two times and a second process P2 that includes at least a second sequence one time. The first sequence comprises: supplying a film deposition gas into a film deposition container in which an object to be deposited is arranged; supplying a first purge gas into the film deposition container in which the object to be deposited is arranged; supplying a first reduction gas into the film deposition container in which the object to be deposited is arranged; supplying a second purge gas into the film deposition container in which the object to be deposited is arranged, in this order. The second sequence includes: supplying a second reduction gas into the film deposition container in which the object to be deposited is arranged; and supplying a third gas into the film deposition container in which the object to be deposited is arranged, in this order.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a film forming method and a film forming apparatus. [Background technology]

[0002] When forming a film by ALD (atomic layer deposition) or the like, it is desirable to perform the film formation process accurately. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6706903 specification Summary of the Invention [Problem to be solved by the invention]

[0004] A film forming method and a film forming apparatus capable of performing an accurate film forming process are provided. [Means for solving the problem]

[0005] A film formation method according to an embodiment is a film formation method that alternates between a first process including at least two first sequences and a second process including at least one second sequence, wherein the first sequence includes supplying a film formation gas into a film formation container in which a film formation target is placed, supplying a first purge gas into the film formation container in which the film formation target is placed, supplying a first reducing gas into the film formation container in which the film formation target is placed, and supplying a second purge gas into the film formation container in which the film formation target is placed, all in the order mentioned; and the second sequence includes supplying a second reducing gas into the film formation container in which the film formation target is placed, and supplying a third purge gas into the film formation container in which the film formation target is placed, all in the order mentioned. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a block diagram showing a basic configuration of a film forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a planar pattern diagram illustrating a configuration of a film formation target placed in a chamber according to an embodiment. [Figure 3] 1 is a cross-sectional view schematically showing a configuration of a film-forming target placed in a chamber according to an embodiment. [Figure 4] FIG. 2 is a cross-sectional view schematically illustrating a structure after a film is formed on a film-forming target according to the embodiment. [Figure 5] FIG. 2 is a diagram schematically illustrating a detailed configuration of a film forming apparatus according to an embodiment. [Figure 6] 1A to 1C are diagrams illustrating basic operations of a film forming method according to an embodiment. [Figure 7] FIG. 2 is a diagram showing a first sequence in the film forming method according to the embodiment. [Figure 8] 1A to 1C are diagrams illustrating a first process in a film forming method according to an embodiment. [Figure 9] 3A to 3C are diagrams schematically illustrating operations performed in a first sequence in the film forming method according to the embodiment. [Figure 10A] 5A to 5C are diagrams illustrating operations performed in a purge gas supply step in the film forming method according to the embodiment; [Figure 10B] 5A to 5C are diagrams illustrating operations performed in a purge gas supply step in the film forming method according to the embodiment; [Figure 11] FIG. 4 is a diagram showing a second sequence in the film forming method according to the embodiment. [Figure 12] 5A to 5C are diagrams illustrating a second process in the film forming method according to the embodiment. [Figure 13A] 3A to 3C are diagrams illustrating a state in which a conductive layer is formed in a gap in the film forming method according to the embodiment. [Figure 13B] 3A to 3C are diagrams illustrating a state in which a conductive layer is formed in a gap in the film forming method according to the embodiment. [Figure 14]10A and 10B are diagrams showing a first specific example of a first modified example of the film forming method according to the embodiment. [Figure 15] 10A and 10B are diagrams showing a second specific example of the first modified example of the film forming method according to the embodiment. [Figure 16] 10A and 10B are diagrams showing a specific example of a second modified example of the film forming method according to the embodiment. [Figure 17] FIG. 10 is a timing chart showing the operation of a third modified example of the film forming method according to the embodiment. [Figure 18] 10 is a flowchart showing the operation of a specific example of a fourth modified example of the film forming method according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment will be described with reference to the drawings.

[0008] FIG. 1 is a block diagram showing the basic configuration of a film forming apparatus according to an embodiment.

[0009] The film formation apparatus shown in FIG. 1 is a film formation apparatus that uses ALD (atomic layer deposition), and includes a chamber (film formation container) 100, a gas supply unit 200, a gas exhaust unit 300, and a control unit 400.

[0010] A film formation target (not shown) is placed in chamber 100, and a film is formed on the film formation target by ALD. A gas supply unit 200 is connected to chamber 100, and a film formation gas (source gas), a reducing gas, and a purge gas are supplied into chamber 100 by the gas supply unit 200. A gas exhaust unit 300 is also connected to chamber 100, and gas within chamber 100 is exhausted by the gas exhaust unit 300. The operations of the gas supply unit 200 and the gas exhaust unit 300 are controlled by a control unit 400. The control operations performed by the control unit 400 will be described in detail later.

[0011] Fig. 2 is a planar pattern diagram showing a schematic configuration of a film-forming target 500 placed in the chamber 100. Fig. 3 is a cross-sectional view showing a schematic configuration of the film-forming target 500 placed in the chamber 100. Fig. 3 corresponds to the cross section taken along line AA in Fig. 2. The film-forming target 500 is for forming a NAND flash memory having a three-dimensional structure.

[0012] 2 and 3, the film-forming target 500 includes a stacked structure 510 and a pillar structure 520 extending in the Z direction within the stacked structure 510. The film-forming target 500 also has a slit 530 extending in the Y direction and the Z direction within the stacked structure 510. The X direction, the Y direction, and the Z direction intersect with each other. More specifically, the X direction, the Y direction, and the Z direction are directions perpendicular to each other.

[0013] The laminated structure 510 has a structure in which a plurality of insulating layers 511 and a plurality of voids 512 are alternately arranged in the Z direction.

[0014] The pillar structure 520 includes a core insulating layer 521, a semiconductor layer 522 surrounding the side surfaces of the core insulating layer 521, a tunnel insulating layer 523 surrounding the side surfaces of the semiconductor layer 522, a charge storage layer 524 surrounding the side surfaces of the tunnel insulating layer 523, and a block insulating layer 525 surrounding the side surfaces of the charge storage layer 524.

[0015] FIG. 4 is a cross-sectional view that schematically shows the structure after a film is formed on the film-forming target 500 by the film-forming apparatus shown in FIG.

[0016] A conductive material is used as the film forming material, and a conductive layer 513 is formed in the region including the void 512 shown in Fig. 3. Specifically, by supplying gas through a slit 530, the conductive layer 513 is formed in the region including the void 512.

[0017] FIG. 5 is a diagram schematically illustrating a detailed configuration of the film forming apparatus shown in FIG.

[0018] A table 110 having a heater is provided in the chamber 100, and a film formation target 500 is set on the table 110. A shower head 120 is provided above the table 110, and a film formation gas, a reducing gas, and a purge gas are supplied from the shower head 120 into the chamber 100.

[0019] A gas supply unit 200 is connected to the chamber 100. The gas supply unit 200 includes a film formation gas (source gas) supply system 210a, a reducing gas supply system 210b, a purge gas supply system 210c, and a gas supply pipe 220. Gases are supplied to the shower head 120 from the gas supply systems 210a, 210b, and 210c via the gas supply pipe 220.

[0020] The deposition gas (source gas) supply system 210a includes a valve 211a, a mass flow controller 212a, a gas tank 213a, and a valve 214a. Similarly, the reduction gas supply system 210b includes a valve 211b, a mass flow controller 212b, a gas tank 213b, and a valve 214b, and the purge gas supply system 210c includes a valve 211c, a mass flow controller 212c, a gas tank 213c, and a valve 214c.

[0021] A gas exhaust unit 300 is connected to the chamber 100. The gas exhaust unit 300 includes an exhaust pump 310, an exhaust pipe 320, a gas detector 330, and a pressure adjustment valve 340.

[0022] A control unit 400 is connected to the gas supply unit 200 and the gas exhaust unit 300, and the gas supply operation of the gas supply unit 200 and the gas exhaust operation of the gas exhaust unit 300 are controlled by the control unit 400.

[0023] Next, a film formation method performed using the above-described film formation apparatus will be described. As already described, in this embodiment, film formation is performed by ALD.

[0024] 6 is a diagram showing the basic operation of the film forming method according to this embodiment. As shown in FIG. 6, in the film forming method according to this embodiment, a first process P1 and a second process P2 are performed alternately.

[0025] FIG. 7 is a diagram showing a first sequence S1 included in a first process P1.

[0026] The first sequence S1 includes step S11 of supplying a film formation gas into a chamber (film formation container) 100, step S12 of supplying a purge gas into the chamber 100, step S13 of supplying a reducing gas into the chamber 100, and step S14 of supplying a purge gas into the chamber 100. The first sequence S1 is performed in the order of step S11, step S12, step S13, and step S14.

[0027] 8, in the first process P1, the above-described first sequence S1 is performed at least twice. That is, steps S11, S12, S13, and S14 are repeatedly performed, such as S11, S12, S13, S14, S11, S12, S13, S14, .

[0028] In step S11, a film formation gas (source gas) is supplied from the film formation gas supply system 210a shown in FIG. 5 into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214a to be open (normally, the valve 211a is always open), thereby supplying the film formation gas into the chamber 100. The film formation gas contains a metal element. Specifically, WF gas containing tungsten (W) and fluorine (F) is used as the film formation gas. The film formation gas may further contain argon (Ar) gas as a carrier gas.

[0029] In step S12, a purge gas is supplied from the purge gas supply system 210c into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214c to be open (normally, the valve 211c is always open), thereby supplying the purge gas into the chamber 100. Argon (Ar) gas is used as the purge gas. The film formation gas is purged by supplying the purge gas.

[0030] In step S13, a reducing gas is supplied from the reducing gas supply system 210b into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214b to be open (normally, the valve 211b is always open), thereby supplying the reducing gas into the chamber 100. Hydrogen gas (H2 gas) is used as the reducing gas. The reducing gas may further contain argon (Ar) gas as a carrier gas.

[0031] In step S14, a purge gas is supplied from the purge gas supply system 210c into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214c to be open (normally, the valve 211c is always open), thereby supplying the purge gas into the chamber 100. As in step S12, argon (Ar) gas is used as the purge gas. The supply of the purge gas purges the reducing gas. In addition, the by-product (HF) generated by the reaction between the film formation gas (WF6 gas) and the reducing gas (H2 gas) is also purged by the purge gas.

[0032] 9 is a diagram schematically illustrating the operations performed in steps S11, S12, S13, and S14 of the first sequence S1 described above. Note that FIG. 9 illustrates a state when the conductive layer (W layer) 513 has been formed to some extent.

[0033] In step S11, a film formation gas (WF gas) is supplied to the surface of the conductive layer 513. In step S12, the WF gas that has not been adsorbed by the conductive layer 513 is purged. In step S13, a reducing gas (H gas) is supplied to the surface of the conductive layer 513. In step S14, hydrogen (H) and fluorine (F) combine to generate HF, and the generated HF is purged. These steps S11 to S14 are repeated, and tungsten (W) is adsorbed to the surface of the conductive layer 513, forming a tungsten (W) atomic layer.

[0034] The number of times the first sequence S1 is performed in each of the first processes P1 is preferably less than twice the number of times the first sequence S1 is performed required to form one atomic layer on the surface (the surface on which the film is to be formed) of the conductive layer 513. By setting the number of times the first sequence S1 is performed in this manner, it is possible to accurately form tungsten (W) atomic layers one atomic layer at a time.

[0035] 10A and 10B are diagrams showing the process of purging HF generated by the reduction reaction in the above-mentioned purge gas supply step S14. Fig. 10A shows the initial state of purge gas supply step S14, and Fig. 10B shows the middle state of purge gas supply step S14.

[0036] 10A and 10B, HF is indicated by a circle. Normally, when HF is adsorbed, H and F are separated and adsorbed at the surface site as shown in step S13 of FIG. 9, but the adsorbed H and F are converted to HF by a reduction reaction and then released again. Therefore, the adsorption state is shown schematically as if they are adsorbed as HF molecules.

[0037] 10A, in the early stage of purge gas supply step S14, the HF adsorption density is reduced only near the end of conductive layer 513 on the slit 530 side. As shown in Fig. 10B, in the middle stage of purge gas supply step S14, the HF adsorption density is reduced even at positions away from the end of conductive layer 513 on the slit 530 side. Therefore, it can be seen that as purge gas supply step S14 progresses, HF present at deep positions in gap 512 is also discharged.

[0038] FIG. 11 is a diagram showing a second sequence S2 included in the second process P2.

[0039] The second sequence S2 includes step S21 of supplying a reducing gas into the chamber 100, and step S22 of supplying a purge gas into the chamber 100. The second sequence S2 is performed in the order of step S21 and step S22.

[0040] In the second process P2, the second sequence S2 described above is performed at least once. That is, the second sequence S2 may be performed only once, or the second sequence S2 may be performed twice or more repeatedly as shown in FIG.

[0041] In step S21, a reducing gas is supplied from the reducing gas supply system 210b into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214b to be open, thereby supplying the reducing gas into the chamber 100. As with the reducing gas in step S13, hydrogen gas (H gas) is used as the reducing gas. The reducing gas may further contain argon (Ar) gas as a carrier gas.

[0042] In step S22, a purge gas is supplied from the purge gas supply system 210c into the chamber 100 via the gas supply pipe 220 and the shower head 120. Specifically, the control unit 400 controls the valve 214c to be open, thereby supplying the purge gas into the chamber 100. As in steps S12 and S14, argon (Ar) gas is used as the purge gas. As in step S14, the supply of the purge gas purges the reducing gas and by-product (HF).

[0043] As can be seen from the above, the reducing gas supply step S21 and the purge gas supply step S22 performed in the second process P2 are basically the same as the reducing gas supply step S13 and the purge gas supply step S14 performed in the first process P1. That is, steps S21 and S22 are performed in the second process P2 consecutively after steps S13 and S14 are performed in the first process P1.

[0044] By alternately performing the first process P1 and the second process P2 described above, the number of atomic layers of tungsten (W) gradually increases, and a conductive layer 513 as shown in Fig. 4 is formed. For example, by performing the second process P2 every time one atomic layer of W layer is formed in the first process P1, the number of atomic layers of tungsten (W) gradually increases while sufficiently exhausting HF.

[0045] As described above, in this embodiment, the first process P1 and the second process P2 are performed alternately. The first process P1 includes at least two first sequences S1, and the second process P2 includes at least one second sequence S2. This method allows for an accurate film formation process, as described below, and enables the conductive layer 513 to be accurately formed.

[0046] As already mentioned, when forming a film by ALD, by-products resulting from the film formation gas and the reducing gas may be adsorbed onto the surface of the film formation target. This may hinder the accurate film formation process or adversely affect the characteristics and reliability of the device. In particular, when forming a conductive layer in a narrow gap, as in the above-described embodiment, it is difficult to efficiently remove by-products from the gap. In addition, when pillar structures 520 are arranged as shown in FIG. 2, it is even more difficult to efficiently remove by-products from the gap. In the above-described embodiment, HF generated by the WF gas (film formation gas) and H gas (reducing gas) may remain in the gap as a by-product, which may adversely affect the characteristics and reliability of the semiconductor device.

[0047] For example, if only the first sequence S1 (film forming gas supply step S11, purge gas supply step S12, reduction gas supply step S13, and purge gas supply step S14) described in the above-mentioned embodiment is repeatedly performed, it cannot be said that the reduction gas supply step S13 and the purge gas supply step S14 are necessarily performed sufficiently, and there is a risk that a large amount of HF will remain in the gap as a by-product.

[0048] To solve the above-mentioned problems, it is considered effective to perform the second sequence S2 (reducing gas supply step S21 and purge gas supply step S22) described in the above-mentioned embodiment after performing the first sequence S1. However, if the second sequence S2 is performed every time the first sequence S1 is performed, the number of times the second sequence S2 is performed increases relatively, and the time required for the entire film formation process becomes longer.

[0049] In this embodiment, the first sequence S1 is performed two or more times in the first process P1, and then the second sequence S2 is performed one or more times in the second process P2. This allows the by-products (HF) in the voids to be efficiently removed, and also prevents the increase in the time required for the entire film formation process. Therefore, in this embodiment, the conductive layer 513 can be formed by an appropriate film formation process, thereby improving the characteristics and reliability of the semiconductor device.

[0050] In this embodiment, the number of times the first sequence S1 is performed in the first process P1 may be constant, or the number of times the first sequence S1 is performed in the first process P1 may be changed, as described later. Similarly, the number of times the second sequence S2 is performed in the second process P2 may be constant, or the number of times the second sequence S2 is performed in the second process P2 may be changed, as described later.

[0051] Next, a first modified example of this embodiment will be described.

[0052] 13A and 13B are diagrams schematically showing a state when a conductive layer 513 is formed in a gap 512. Fig. 13A shows a state at the beginning of film formation, and Fig. 13B shows a state at the middle of film formation.

[0053] As shown in Figure 13A, in the early stage of film formation, conductive layer 513 is barely formed and gap 512 is relatively wide. Therefore, by-products (HF) are relatively easily discharged. In contrast, as shown in Figure 13B, in the middle stage of film formation, the thickness of conductive layer 513 increases and gap 512 becomes narrower. Therefore, by-products (HF) are less likely to be discharged.

[0054] In this modified example, based on the discharge characteristics described above, control is performed so that the number of times the second sequence S2 in the second process P2 increases as the film formation progresses, i.e., as the thickness of the conductive layer 513 increases.

[0055] Generally speaking, where p is a desired positive integer greater than or equal to 1 and a is a desired positive integer greater than or equal to 1, control is performed so that the number of times the second sequence S2 occurs in the (p+a)th second process P2 is greater than the number of times the second sequence S2 occurs in the pth second process P2.

[0056] 14 is a diagram showing a first specific example of this modification. The horizontal axis represents the number of basic processes (first process P1+second process P2), and the vertical axis represents the number of second sequences S2 in the second process P2.

[0057] 14, in this specific example, the number of times the second sequence S2 is performed in the second process P2 increases as the number of times the basic process is performed increases, i.e., as the thickness of the conductive layer 513 increases. Specifically, every time the basic process is performed a certain number of times (k times), the number of times the second sequence S2 is performed increases to m1, m2, m3, and m4. Note that the value of m2-m1, the value of m3-m2, and the value of m4-m3 may be the same or different.

[0058] 15 is a diagram showing a second specific example of this modification. The horizontal axis represents the number of basic processes (first process P1+second process P2), and the vertical axis represents the number of second sequences S2 in the second process P2.

[0059] 15, in this example, as the number of times of the basic process increases, the number of times of the second sequence S2 in the second process P2 also increases. Specifically, as the number of times of the basic process increases, the period until the number of times of the second sequence S2 increases becomes shorter. In other words, the relationship is k1>(k2-k1)>(k3-k2)>(k4-k3).

[0060] As described above, the basic control method of this modification is the same as that of the above-described embodiment, and the same effects as those of the above-described embodiment can be obtained. Furthermore, in this modification, the above-described control method makes it possible to more effectively discharge by-products from within the gaps, and more effectively suppress an increase in the time required for the entire film formation process.

[0061] Next, a second modification of this embodiment will be described.

[0062] 13A and 13B, the gap 512 is relatively wide in the early stage of film formation, and narrows as film formation progresses. Therefore, as film formation progresses, it becomes more difficult to discharge the by-product (HF). From another perspective, it is considered that in the early stage of film formation, even if the number of times of the first sequence in the first process P1 is relatively large, the by-product (HF) can be discharged relatively easily.

[0063] Therefore, in this modification, control is performed so that the number of times the first sequence is performed in the first process P1 is relatively reduced as the film formation progresses.

[0064] Generally speaking, where q is a desired positive integer greater than or equal to 1 and b is a desired positive integer greater than or equal to 1, control is performed so that the number of times the first sequence S1 occurs in the (q+b)th first process P1 is less than the number of times the first sequence S1 occurs in the qth first process P1.

[0065] 16 is a diagram showing a specific example of this modification. The horizontal axis represents the number of basic processes (first process P1+second process P2), and the vertical axis represents the number of first sequences S1 in the first process P1.

[0066] 16, in this specific example, the number of times the first sequence S1 is performed in the first process P1 decreases as the number of times the basic process is performed increases, i.e., as the thickness of the conductive layer 513 increases. Specifically, every time the basic process is performed a certain number of times (k times), the number of times the first sequence S1 is performed decreases to n4, n3, n2, and n1. Note that the value of n2-n1, the value of n3-n2, and the value of n4-n3 may be the same or different.

[0067] As described above, the basic control method of this modification is the same as that of the above-described embodiment, and the same effects as those of the above-described embodiment can be obtained. Furthermore, in this modification, the above-described control method makes it possible to more effectively discharge by-products from within the gaps, and more effectively suppress an increase in the time required for the entire film formation process.

[0068] In addition, the first and second modified examples described above may be combined to change both the number of times the first sequence S1 is performed in the first process P1 and the number of times the second sequence S2 is performed in the second process P2.

[0069] Next, a third modified example of this embodiment will be described.

[0070] 5, the film forming gas, the reducing gas, and the purge gas are supplied into the chamber 100 via the gas tank 213a, the gas tank 213b, and the gas tank 213c, respectively. In this modification, the film forming gas is controlled not to be supplied to the gas tank 213a at least while the second process P2 is being performed. That is, the film forming gas is prevented from being supplied to the gas tank 213a by controlling the valve 211a.

[0071] FIG. 17 is a timing chart showing the gas supply operation (gas supply operation to the chamber 100) of this modified example.

[0072] 17, after the film formation gas is finally supplied into the chamber 100 in the first process, the film formation gas is not supplied into the chamber 100 until the next first process is started. Therefore, during the period of the second process P2 in which the film formation gas is not supplied into the chamber 100, the control unit 400 keeps the valve 211a closed to prevent the film formation gas from being supplied to the gas tank 213a.

[0073] In this modification, the basic control method is the same as in the above-described embodiment, and the same effects as in the above-described embodiment can be obtained. Furthermore, in this modification, by performing the control as described above, it is possible to prevent the pressure in the gas tank 213a from becoming too high due to the continuous supply of the film forming gas to the gas tank 213a during the second process.

[0074] Next, a fourth modified example of this embodiment will be described.

[0075] 5, the gas exhaust unit 300 includes an exhaust pump 310, an exhaust pipe 320, and a gas detector 330, and the gas detector 330 is connected to the exhaust pipe 320. The gas detector 330 is capable of detecting the amount of by-products (HF). In this modification, the first process P1 and the second process P2 are controlled based on the detection result of the by-products (HF) by the gas detector 330. That is, in this modification, the first process P1 and the second process P2 are controlled based on the amount of by-products generated in the chamber 100.

[0076] Fig. 18 is a flowchart showing the operation of a specific example of this modification. In the example shown in Fig. 18, the number of times the second sequence S2 in the second process P2 is performed is controlled based on the amount of by-product (HF) detected by the gas detector 330.

[0077] First, a value based on the amount of by-product (HF) discharged in the purge gas supply step is detected by the gas detector 330, and the detected value is sent to the control unit 400 (step 1).

[0078] The control unit 400 determines the number of times the second sequence S2 is performed in the second process P2 based on the detected value. For example, the number of times the second sequence S2 is performed is determined based on the change over time in the detected value (corresponding to the change over time in the amount of discharged HF) (step 2).

[0079] Furthermore, the second process P2 is executed the determined number of times of the second sequence S2 (step 3).

[0080] In this modification, the basic control method is the same as in the above-described embodiment, and it is possible to obtain the same effects as in the above-described embodiment. Furthermore, in this modification, the above-described control method can optimize the number of times the second sequence S2 is performed, and it is possible to accurately control the first process P1 and the second process P2.

[0081] In the above-described specific example, the number of times the second sequence S2 is performed in the second process P2 is determined based on the detection result of the gas detector 330. However, the number of times the first sequence S1 is performed in the first process P1 may be determined based on the detection result of the gas detector 330.

[0082] In the above-described embodiment and modified examples, a case where a W layer is formed in the void 512 has been described. However, a block insulating layer (such as an AlO layer) and a barrier metal layer (such as a TiN layer) may be formed in this order along the side surface of the void 512, and then a W layer may be formed in the void 512 with the block insulating layer and barrier metal layer formed therein. A control method similar to the above-described control method can also be applied when a TiN layer is formed as a barrier metal layer. In this case, TiCl4 can be used as the film formation gas (source gas), NH3 can be used as the reducing gas, and N2 can be used as the purge gas.

[0083] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0084] 100... chamber (film formation container) 110... table 120... shower head 200...gas supply unit 210a...film formation gas supply system 210b...reducing gas supply system 210c...purge gas supply system 211a, 211b, 211c... Valves 212a, 212b, 212c...Mass flow controllers 213a, 213b, 213c...Gas tank 214a, 214b, 214c... Valves 220...Gas supply pipe 300...gas exhaust unit 310...exhaust pump 320...Exhaust pipe 330...Gas detector 400...Control unit 500... Film formation target 510... Laminated structure 511... Insulating layer 512: Gap 513: Conductive layer 520... Pillar structure 521... Core insulating layer 522... Semiconductor layer 523...Tunnel insulating layer 524...Charge storage layer 525...Block insulating layer 530...Slit

Claims

1. A film forming method that alternately performs a first process including at least two first sequences and a second process including at least one second sequence, the first sequence includes a first step of supplying a film formation gas into a film formation container in which a film formation target is placed, a second step of supplying a first purge gas into the film formation container in which the film formation target is placed, a third step of supplying a first reducing gas into the film formation container in which the film formation target is placed, and a fourth step of supplying a second purge gas into the film formation container in which the film formation target is placed, performed in the order of the first step, the second step, the third step, and the fourth step; the second sequence includes a fifth step of supplying a second reducing gas into the film formation container in which the film formation target is placed, and a sixth step of supplying a third purge gas into the film formation container in which the film formation target is placed, the fifth step and the sixth step being performed in this order; Let p be a desired positive integer greater than or equal to 1, and let a be a desired positive integer greater than or equal to 1, The number of times the second sequence is performed in the (p+a)th second process is greater than the number of times the second sequence is performed in the pth second process. Film formation method.

2. A film forming method that alternately performs a first process including at least two first sequences and a second process including at least one second sequence, the first sequence includes a first step of supplying a film formation gas into a film formation container in which a film formation target is placed, a second step of supplying a first purge gas into the film formation container in which the film formation target is placed, a third step of supplying a first reducing gas into the film formation container in which the film formation target is placed, and a fourth step of supplying a second purge gas into the film formation container in which the film formation target is placed, performed in the order of the first step, the second step, the third step, and the fourth step; the second sequence includes a fifth step of supplying a second reducing gas into the film formation container in which the film formation target is placed, and a sixth step of supplying a third purge gas into the film formation container in which the film formation target is placed, the fifth step and the sixth step being performed in this order; Let q be a desired positive integer greater than or equal to 1, and let b be a desired positive integer greater than or equal to 1, The number of times of the first sequence in the (q+b)th first process is less than the number of times of the first sequence in the qth first process. Film formation method.

3. the deposition gas is supplied to the deposition container via a gas tank; During the second process, the deposition gas is not supplied to the gas tank. The film forming method according to claim 1 or 2.

4. The first and second processes are controlled based on the amount of by-products generated in the deposition chamber. The film forming method according to claim 1 or 2.

5. The film formation method is a film formation method using ALD (atomic layer deposition). The film forming method according to claim 1 or 2.

6. The number of times of the first sequence included in each of the first processes is less than twice the number of times of the first sequence required to form one atomic layer on the surface of the film formation target. The film forming method according to claim 1 or 2.

7. The deposition gas contains a metal element. The film forming method according to claim 1 or 2.

8. The first reducing gas and the second reducing gas are the same reducing gas. The film forming method according to claim 1 or 2.

9. The first purge gas, the second purge gas, and the third purge gas are the same purge gas. The film forming method according to claim 1 or 2.

10. the film-forming target has a structure in which a plurality of insulating layers and a plurality of voids are alternately arranged, By alternately performing the first process and the second process, a plurality of conductive layers are formed in the plurality of voids. The film forming method according to claim 1 or 2.

11. a film formation container; a gas supply unit that supplies a gas into the deposition chamber; a control unit that controls the gas supply unit; A film forming apparatus comprising: the control unit controls the gas supply unit so that a first process including at least two first sequences and a second process including at least one second sequence are alternately performed; the first sequence includes a first step of supplying a film formation gas into the film formation container in which a film formation target is placed, a second step of supplying a first purge gas into the film formation container in which the film formation target is placed, a third step of supplying a first reducing gas into the film formation container in which the film formation target is placed, and a fourth step of supplying a second purge gas into the film formation container in which the film formation target is placed, performed in the order of the first step, the second step, the third step, and the fourth step; the second sequence includes a fifth step of supplying a second reducing gas into the film formation container in which the film formation target is placed, and a sixth step of supplying a third purge gas into the film formation container in which the film formation target is placed, the fifth step and the sixth step being performed in this order; Let p be a desired positive integer greater than or equal to 1, and let a be a desired positive integer greater than or equal to 1, The control unit controls the gas supply unit so that the number of times of the second sequence in the (p+a)th second process is greater than the number of times of the second sequence in the pth second process. Film deposition equipment.

12. a film formation container; a gas supply unit that supplies a gas into the deposition chamber; a control unit that controls the gas supply unit; A film forming apparatus comprising: the control unit controls the gas supply unit so that a first process including at least two first sequences and a second process including at least one second sequence are alternately performed; the first sequence includes a first step of supplying a film formation gas into the film formation container in which a film formation target is placed, a second step of supplying a first purge gas into the film formation container in which the film formation target is placed, a third step of supplying a first reducing gas into the film formation container in which the film formation target is placed, and a fourth step of supplying a second purge gas into the film formation container in which the film formation target is placed, performed in the order of the first step, the second step, the third step, and the fourth step; the second sequence includes a fifth step of supplying a second reducing gas into the film formation container in which the film formation target is placed, and a sixth step of supplying a third purge gas into the film formation container in which the film formation target is placed, the fifth step and the sixth step being performed in this order; Let q be a desired positive integer greater than or equal to 1, and let b be a desired positive integer greater than or equal to 1, The control unit controls the gas supply unit so that the number of times of the first sequence in the (q+b)th first process is less than the number of times of the first sequence in the qth first process. Film deposition equipment.

13. the deposition gas is supplied to the deposition container via a gas tank included in the gas supply unit, The control unit controls the gas supply unit so that the film forming gas is not supplied to the gas tank during the second process. The film forming apparatus according to claim 11 or 12.

14. The control unit controls the gas supply unit so that the first and second processes are performed based on the amount of by-products generated in the film formation chamber. The film forming apparatus according to claim 11 or 12.

15. The film forming apparatus is a film forming apparatus that uses ALD (atomic layer deposition). The film forming apparatus according to claim 11 or 12.

16. The number of times of the first sequence included in each of the first processes is less than twice the number of times of the first sequence required to form one atomic layer on the surface of the film formation target. The film forming apparatus according to claim 11 or 12.

17. The deposition gas contains a metal element. The film forming apparatus according to claim 11 or 12.

18. The first reducing gas and the second reducing gas are the same reducing gas. The film forming apparatus according to claim 11 or 12.

19. The first purge gas, the second purge gas, and the third purge gas are the same purge gas. The film forming apparatus according to claim 11 or 12.

20. The film-forming target has a structure in which a plurality of insulating layers and a plurality of voids are alternately arranged. The film forming apparatus according to claim 11 or 12.

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