JP2019083231A - Deposition device and deposition method - Google Patents

Abstract

To improve uniformity of a film thickness internal surface distribution of a peripheral direction of a thin film on a substrate.SOLUTION: When forming a film to a target film thickness by repeating plural times one cycle containing each step of an adsorption of an original gas, displacement of a processing atmosphere, and generation of a reaction product by a reaction of the original gas and the reaction gas, a placing table is intermittently rotated in each cycle so that the placing table performs N rotations. A rotation speed Rs of the placing table can be obtained on the basis of a step time tp of a step Sp (adsorption step S1) of which a step time is shortest from the step time in the steps influencing a film thickness internal surface of a peripheral direction, and the placing table is rotated in a time band when the step Sp is performed. Therefore, a position in the peripheral direction of a wafer W when the step Sp is performed is sequentially deviated, the film thickness distribution in each position is overlapped, and the wafer W becomes the N rotations in the termination of deposition. As a result, uniformity of the internal surface distribution of the peripheral direction in the film thickness is improved.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technology for laminating a reaction product on a substrate by repeating a cycle in which a source gas adsorbed on a substrate is reacted with a reaction gas to generate a reaction product.

  In a manufacturing step of a semiconductor device, a film formation process is performed by ALD (Atomic Layer Deposition) on a semiconductor wafer (hereinafter, referred to as a wafer) which is a substrate, by thermal energy or by forming plasma. . In this film forming process, for example, a processing gas is supplied from a gas shower plate, which is provided in a processing vessel and serves as the upper electrode, to a wafer mounted on a stage that also serves as the lower electrode. The deposition is performed using a film formation apparatus that forms a plasma of a processing gas between the two.

  In this apparatus, the raw material gas is adsorbed on the wafer, for example, the reactive gas is supplied in parallel with the supply of the raw material gas, and the plasma is intermittently formed to activate the reactive gas and activate the reactive gas active species and the wafer. Reaction with the adsorbed source gas produces a reaction product. Then, a thin film having a desired film thickness is formed by repeating a plurality of cycles of alternately performing the step of supplying the source gas and the step of reacting the source gas and the reaction gas. In the dry etching process, which is the next process, the etching rate is adjusted concentrically in many cases, etc., in such an ALD process, a film thickness profile such that the film thickness in the circumferential direction becomes uniform in the wafer surface. May be required to control the

  That is, if the uniformity of the film thickness in the circumferential direction is good, the convex shape in which the film thickness at the central portion is larger than that at the peripheral portion as viewed in the radial direction of the wafer Even in the case of the concave shape which is smaller than the above, the film thickness distribution in the radial direction can be equalized in the later dry etching step. However, in the ALD process, processing may locally proceed in the wafer surface in a specific step, and variations in film thickness may occur.

  Patent Document 1 and Patent Document 2 propose a technique for improving the uniformity of the film thickness in the circumferential direction of the substrate by rotating the substrate in revolving the substrate placed on the rotary table and performing the ALD process. ing. Further, in Patent Document 3, a boat holding multiple substrates in multiple stages is carried into a reaction tube, and at least two kinds of gases are alternately supplied to perform an ALD process, the gas supply period and the wafer rotation period are different. A technique for improving the in-plane uniformity of film thickness by controlling so as not to be synchronized is described. However, these Patent Documents 1 to 3 do not focus on the progress of the local processing in a specific step, and can not solve the problem of the present invention.

JP, 2016-92156, A JP, 2016-206025, A International Publication WO 2005/088692

  The present invention has been made under such circumstances, and an object thereof is to provide a technique for improving the uniformity of circumferential in-plane distribution in the film thickness of a thin film on a substrate.

The present invention comprises one cycle including the steps of: adsorbing a source gas on a substrate; replacing the processing atmosphere with a replacement gas; and reacting the source gas adsorbed on the substrate with a reaction gas to generate a reaction product. In a film forming apparatus for laminating a reaction product on a substrate repeatedly a plurality of times,
A processing container for placing a substrate mounting table therein and forming a vacuum processing atmosphere;
A rotation mechanism for rotating the mounting table;
A control unit that controls the rotation mechanism;
The control unit
Assuming that the number of repetitions of one cycle is M, the table is intermittently rotated by an angle represented by 360 degrees × {N (an integer of 1 or more) / M}.
Among the steps that affect the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle, let Sp be the step with the shortest step time required for the step, and tp be the step time of the step Sp. And outputting a control signal to rotate the mounting table in a time zone including at least a part while the step Sp is being performed,
An average rotation speed Rs of the mounting table from when the step Sp is started to when the mounting table stops is characterized by Rs = (N / M) × (1 / tp).

Further, the present invention includes the steps of: adsorbing a source gas on a substrate; replacing the processing atmosphere with a replacement gas; and reacting the source gas adsorbed on the substrate with a reaction gas to generate a reaction product. In a film forming apparatus in which a reaction product is laminated on a substrate by repeating a plurality of cycles.
A processing container for placing a substrate mounting table therein and forming a vacuum processing atmosphere;
A rotation mechanism for rotating the mounting table;
A control unit that controls the rotation mechanism;
Among the steps affecting the in-plane distribution in the circumferential direction in the film thickness of the thin film on the substrate, the control unit Sp in the one cycle is a step having the shortest step time required for the step Sp, the step of the step Sp Assuming that the time is tp, a control signal is output so as to rotate the mounting table N (an integer of 1 or more) at time tp including a time zone of 80% or more while the step Sp is performed. It is characterized by being.

Furthermore, in the present invention, in the vacuum processing atmosphere, the step of causing the substrate mounted on the mounting table to adsorb the source gas, the step of replacing the processing atmosphere with the replacement gas, and the reaction of the source gas adsorbed on the substrate and the reaction gas Forming a reaction product by laminating the reaction product on the substrate by repeating a cycle including a step of causing the reaction product to form a reaction product;
Intermittently rotating the table by an angle represented by 360 degrees × {N (an integer of 1 or more) / M}, where M represents the number of repetitions of one cycle.
In the step of intermittently rotating the mounting table, one of the steps affecting the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle has the shortest step time required for the step. Sp, assuming that the step time of the step Sp is tp, is a step of rotating the mounting table in a time zone including at least a part while the step Sp is being performed,
An average rotation speed Rs of the mounting table from when the step Sp is started to when the mounting table stops is characterized by Rs = (N / M) × (1 / tp).

Furthermore, in the present invention, in the vacuum processing atmosphere, the step of causing the substrate mounted on the mounting table to adsorb the source gas, the step of replacing the processing atmosphere with the replacement gas, the source gas adsorbed on the substrate and the reaction gas A film forming step of laminating a reaction product on a substrate by repeating one cycle including a step of reacting to form a reaction product a plurality of times;
Among the steps that affect the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle, let Sp be the step with the shortest step time required for the step, and tp be the step time of the step Sp. The mounting table is rotated N (an integer of 1 or more) at a time tp including a time zone of 80% or more while the step Sp is performed.

  In the present invention, when a film is formed to a target film thickness by repeating one cycle including each step of adsorption of the source gas, substitution of the processing atmosphere, and generation of a reaction product by reaction of the source gas and the reaction gas The mounting table is intermittently rotated in each cycle so that the substrate mounting table rotates N times. The average rotation speed Rs of the mounting table at this time is obtained based on the step time tp of the step Sp having the shortest step time among the steps affecting the film thickness in-plane distribution in the circumferential direction, and the step Sp is performed. The mounting table is rotated in the time zone including the time zone. Therefore, the circumferential position of the substrate when step Sp is performed is sequentially displaced, the film thickness distribution at each position is superimposed, and the substrate is rotated N times at the end of film formation. As a result, the uniformity of the circumferential in-plane distribution in the film thickness is improved.

  Further, in another aspect of the present invention, in the one cycle, among the steps affecting the in-plane distribution in the circumferential direction of the film thickness of the thin film on the substrate, the step Sp having the shortest step time is required. The mounting table is rotated N (an integer of 1 or more) at a time tp including a time zone of 80% or more. Therefore, since the substrate rotates N times each time step Sp is performed, the uniformity of the in-plane distribution in the circumferential direction in the film thickness is improved.

It is a longitudinal side view showing the film deposition system concerning an embodiment of the invention. It is a schematic perspective view of the film-forming apparatus. It is a chart figure which shows the film-forming method implemented by the film-forming apparatus. It is a top view explaining an operation of a film deposition system. It is a chart figure which shows the other film-forming method implemented by the film-forming apparatus. It is a top view which shows the other film-forming method implemented by the film-forming apparatus.

  A film forming apparatus according to an embodiment of the present invention will be described by way of example applied to a film forming apparatus for forming a film on a wafer W by plasma ALD (Atomic Layer Deposition). For example, as shown in FIG. 1, the film forming apparatus 1 includes a processing container 10 having a rectangular cross section. In the figure, reference numeral 101 denotes a ceiling member of the processing container 10, and reference numeral 102 denotes a container body. A loading / unloading port 11 for loading / unloading the wafer W is formed on the side wall of the processing container 10, and the loading / unloading port 11 is opened and closed by the gate valve 12. In the processing container 10, for example, two substrate processing units 13 and 14 are arranged side by side as viewed from the loading / unloading port 11 and on the back side. An exhaust port 15 for exhausting the atmosphere in the processing container 10 is provided on the bottom surface of the processing container 10, and the exhaust port 15 is connected to a vacuum pump 17 forming an evacuation mechanism via an exhaust pipe 16. There is. Reference numeral 18 in FIG. 1 denotes a pressure adjustment unit that adjusts the pressure in the processing container 10.

  Since the substrate processing units 13 and 14 are configured in the same manner, the substrate processing unit 13 will be described as an example. The substrate processing unit 13 includes a mounting table 21 on which the wafer W is mounted, as shown in FIG. The mounting table 21 doubles as a lower electrode, and is formed in a flat cylindrical shape made of metal such as aluminum or nickel, for example, and can be moved up and down via a drive shaft 221 by a drive mechanism 22 which doubles as a rotation mechanism. It is configured to be rotatable around.

  In FIG. 1, the mounting table 21 in the processing position is drawn by solid lines, and the mounting table 21 in the delivery position is shown by dotted lines. The processing position is a position at which a film forming process to be described later is performed, and the delivery position is a position at which the wafer W is delivered to / from an external transfer mechanism (not shown). A heater 23 for heating the wafer W on the mounting surface is embedded in the mounting table 21 and configured to heat the wafer W to, for example, about 300 ° C. to 450 ° C. Further, the mounting table 21 is connected to the ground potential through a matching unit (not shown).

  Furthermore, on the upper side of the substrate processing units 13 and 14, a metal gas shower head 4 forming an upper electrode is provided via an insulating member 31. In the figure, reference numeral 101 denotes a ceiling member of the processing container 10, and the processing container 10 is configured of a lid 101 and a container main body 102. A high frequency power supply 33 is connected to the gas shower head 4 via a matching unit 32. Thus, the film forming apparatus 1 is configured as a parallel plate type plasma processing apparatus that applies high frequency power between the gas shower head 4 and the mounting table 21 to generate plasma.

  The gas shower head 4 includes a lid 41, a shower plate 42 provided to face the mounting surface of the mounting table 21, and a flat gas formed between the lid 41 and the shower plate 42. The flow-through chamber 43 is provided. The gas supply passage 5 is connected to the lid 41, and gas supply holes 44 penetrating in the thickness direction are arranged, for example, vertically and horizontally in the shower plate 42, and the gas is directed to the mounting table 21 in a shower shape. Supplied.

  The upstream side of the gas supply path 5 connected to the gas shower head 4 is branched and connected to, for example, a supply source 51 of a source gas, a supply source 52 of a replacement gas, and a supply source 53 of a reaction gas. In FIG. 1, V1 to V3 denote valves, and C1 to C3 denote flow rate adjusters. As a source gas, for example, a gas containing silicon (Si) such as Si 2 Cl 6, Si 2 H 6, HCDS (hexachlorodisilane), TDMAS (tridimethylaminosilane), BDEAS (bisdiethylaminosilane) is used. As a reaction gas, an oxidation gas or a reduction gas is used according to the application, and, for example, an oxygen (O 2) gas, an ozone (O 3) gas, or the like can be used as the oxidation gas. For example, an inert gas such as argon (Ar) gas is used as the replacement gas.

  Furthermore, while a plurality of, for example, three delivery pins 20 are provided on the bottom surface of the processing container 10 at positions corresponding to the respective mounting tables 21, the mounting table 21 is provided with a passage area for the delivery pins 20. Through holes 24 are formed. When the mounting table 21 is lowered to the delivery position, the delivery pin 20 passes through the through hole 24, and the upper end of the delivery pin 20 protrudes from the placement surface of the mounting table 21. Thus, the wafer W is transferred between the transfer mechanism and each mounting table 21 by the cooperative action of an external transfer mechanism (not shown), the delivery pin 20 and the mounting table 21. Reference numeral 25 in FIG. 1 denotes a seal member for keeping the inside of the processing container 10 airtight.

  Furthermore, as shown in FIG. 1 and FIG. 2, in each of the substrate processing units 13 and 14, the film forming apparatus 1 is located between the mounting surface of the mounting table 21 at the processing position and the lower surface of the gas shower head 4. In order to form the processing areas A1 and A2 in the above, a dividing member 26 made of an insulating member is provided. The partitioning member 26 is formed so as to surround the processing regions A1 and A2, respectively, and an opening 261 for delivering the substrate to the mounting table 21 of the substrate processing units 13 and 14 is formed by an external transfer mechanism. .

  FIG. 2 schematically shows a configuration in which two film forming apparatuses 1 including the substrate processing units 13 and 14 are connected, and one film forming apparatus 1 is provided with a lid 41 of the gas shower head 4. The other film forming apparatus 1 has a structure in which the lid 41 is removed. The other film-forming apparatus 1 has shown the mode that the mounting base 21 was arrange | positioned in the delivery position.

  The film forming process of the wafer W performed by the film forming apparatus 1 will be briefly described with reference to FIG. This film forming process repeats one cycle including the adsorption step S1, the first substitution step S2, the reaction step S3 and the second substitution step S4 a plurality of times, for example, 100 times. In FIG. 3, the step time of each step S1 to S4 (the time when the step is being performed) is set to t1 to t4.

  The adsorption step S1 is a step of adsorbing the source gas to the wafer W, and the first replacement step S2 is a step of replacing the atmosphere of the processing areas A1 and A2 as the processing atmosphere with a replacement gas. The reaction step S3 is a step of reacting the source gas adsorbed on the wafer W with the reaction gas to generate a reaction product, and the second replacement step S4 is a processing area A1, A2 before the source gas is supplied. And the step of replacing the atmosphere with a replacement gas. Then, by repeating one cycle of steps S1 to S4 a set number of times, a layer of silicon oxide film as a reaction product is laminated on the surface of wafer W to form a SiO2 film of a predetermined film thickness. .

  The film forming apparatus 1 is provided with a control unit 6 composed of a computer. The control unit 6 includes, for example, a program, a memory, and a data processing unit including a CPU. In the program, a control signal is sent from the control unit 6 to each unit of the film forming apparatus 1, and an instruction is incorporated so that the film forming process described above can be performed. Specifically, the drive mechanism 22 of the mounting table 21, the valves V1 to V3, the flow rate adjusting units C1 to C3, the high frequency power supply 33, the pressure adjusting unit 18, the heater 23, and the like are controlled by the above program. These programs are stored in a storage medium such as a compact disk, hard disk, MO (magneto-optical disk) or the like, and installed in the control unit 6.

The program also includes a program for controlling the rotation of the mounting table 21. This program is configured to intermittently rotate the mounting table 21 at an average rotation speed Rs by an angle represented by 360 degrees × {N / M}, where M is the number of repetitions of one cycle of film forming processing. ing. The average rotation speed Rs is a speed obtained by the following equation (1).
Rs = (N / M) × (1 / tp) (1)

  In the equation (1), tp means that the step time required for the step is the shortest among the steps that affect the circumferential in-plane distribution of the film thickness of the thin film on the wafer W in one cycle of the film forming process. It is a step time of step Sp. Further, the number M of repetitions of the film formation cycle is determined by the target film thickness (Å) and the film formation rate per cycle (Å / cycle). Furthermore, N is the number of rotations of the wafer W when one cycle is repeated M times, and is an integer of 1 or more.

  Then, the program for controlling the rotation rotates the mounting table 21 in a time zone including at least a part while the step Sp is being performed, from when the step Sp is started to when the mounting table 21 stops. Control is performed such that the average rotation speed of the mounting table 21 becomes Rs. The time zone including at least a part during the execution of the step Sp is a time zone including 30% or more during the execution of the step Sp, preferably a time zone including 50% or more. A still more preferable operation is an operation in which the mounting table 21 starts rotating simultaneously with the start of step Sp and the rotation of the mounting table 21 stops at the end of step Sp. In this case, the mounting table 21 is rotated in a time zone of 100% while the step Sp is being performed.

  Here, in one cycle of the film forming process, the step having an influence on the in-plane distribution in the circumferential direction in the film thickness of the thin film on the wafer W is, in this example, an adsorption step S1 for adsorbing the source gas to the wafer W The reaction step S3 is to react the source gas adsorbed on the wafer W with the reaction gas to generate a reaction product. When the step time t1 of the adsorption step S1 and the step time t3 of the reaction step S3 are compared, since the step time t1 is shorter, the step Sp is the adsorption step S1 and the step tp is the step time of the adsorption step S1.

  Concretely, the rotation start time of the mounting base 21 is the start time of step Sp (suction step S1), and the case where the mounting base 21 rotates at a constant speed will be described as an example. For example, assuming that N is 1, the number of repetitions M is 100, and the step time tp of the adsorption step S1 is 0.05 seconds (0.05 / 60 minutes), the average rotation speed Rs is 12 rpm according to equation (1). Further, the rotation angle θ of the mounting table 21 is 3.6 degrees from 360 degrees × (1/100).

  Thus, in each cycle of the film forming process shown in FIG. 3, the control unit 6 outputs a control signal to the mounting table 21 so as to rotate by 12 rpm at the start time of the suction step S1. As a result, the wafer W is subjected to the average rotation speed Rs, which is equal to the constant rotation speed in this case, by the rotation angle θ (3.6 degrees) during the step time tp (0.05 seconds) of the suction step S1 every cycle The rotation is performed at Rs (12 rpm), and the rotation is stopped during the other steps S2 to S4. Thus, the wafer W is controlled to rotate N times (one rotation) when the number of repetitions M is performed, that is, when the target film thickness is reached.

  For example, the average rotational speed Rs is written together with the number of repetitions M and N of the cycle, step Sp and step time tp in the recipe of the film forming process, and the mounting table 21 is selected by selecting the recipe stored in the memory. A control signal is output to rotate. In addition, a display unit may be provided in the control unit 6 so that the step time can be appropriately changed through the display unit. In this case, for example, a step (in this example, the adsorption step S1 and the reaction step S3 in this example) which affects the in-plane distribution in the circumferential direction of the film thickness is specified beforehand in the recipe, and the step Sp having the shortest step time is selected. It is also possible to automatically compare and select, to calculate the average rotation speed Rs based on this, and to output a control signal so as to rotate the mounting table 21 using this data.

  Subsequently, a film forming process of the wafer W performed by the film forming apparatus 1 will be described. First, with the inside of the processing container 10 set to a predetermined vacuum atmosphere and the two mounting tables 21 positioned at the delivery position, the gate valve 12 is opened, and the transfer chamber from the vacuum atmosphere adjacent to the processing container 10 is transferred by the transfer mechanism, for example The two wafers W are simultaneously delivered to the delivery pins 20 protruding from the respective mounting tables 21. When the wafer W is transferred to the mounting table 21 by lifting and lowering the mounting table 21 and the transfer mechanism is withdrawn from the processing container 10, the gate valve 12 is closed and the mounting table 21 is raised to the processing position to process the processing area A1. , A2. Further, the wafer W is heated to a predetermined temperature by the heater 23.

  Next, in the substrate processing units 13 and 14, the valve V2 for substitution gas supply and the valve V3 for reaction gas supply are opened, respectively, and Ar gas from the substitution gas supply source 52, for example, O 2 gas from the reaction gas supply source 53 Are supplied to the processing areas A1 and A2. Subsequently, the valve V1 for supplying the source gas is opened, and the source gas 51 of the source gas is discharged to the processing areas A1 and A2 through the gas shower head 4, and the source gas molecules (silicon atoms serving as silicon precursors) Material) is adsorbed (adsorption step S1). During the step time tp (0.05 seconds) of this suction step S1, the wafer W is rotated at 12 rpm which is a preset average rotation speed Rs (herein, constant speed rotation speed Rs).

  Subsequently, the valve V1 is closed, the supply of the source gas to the wafer W is stopped, and the rotation of the wafer W is stopped. Subsequently, by continuing the supply of Ar gas, the source gas remaining in the processing areas A1 and A2 and not adsorbed on the wafer W is purged with Ar gas to replace the atmosphere in the processing areas A1 and A2 (first process). Replacement step S2).

  Next, the high frequency power supply 33 is turned on. At this time, O 2 gas and Ar gas are supplied to the processing areas A 1 and A 2, and the O 2 gas in the processing areas A 1 and A 2 is plasmatized by application of high frequency power, and adsorbed onto the wafer W by this plasma. The raw material gas is oxidized to form a silicon oxide layer as a reaction product (reaction step S3). Next, the high frequency power supply 33 is turned off, and the supply of Ar gas is continued to purge the reactive species of plasma remaining in the processing areas A1 and A2 to Ar gas, and from the processing areas A1 and A2 It removes (2nd substitution step S4).

  Thereafter, the valve V1 is opened again to supply the source gas, and the adsorption step S1 is performed while rotating the wafer W at the rotation speed Rs. Subsequently, four steps of first substitution step S2, reaction step S3 and second substitution step S4 are performed, and the film forming cycle consisting of steps S1 to S4 is repeatedly performed 100 times, which is the number M of times, to obtain a wafer. A SiO 2 film of a target thickness is formed on the surface of W.

  As described above, when the first cycle starts, the wafer W rotates at the same rotational speed Rs (12 rpm) for 0.05 seconds while the suction step S1 is being performed. Rotate by 3.6 degrees) and then rest until the remaining time of one cycle has elapsed. After that, when the second cycle starts, rotation is performed by the rotation angle θ at the rotation speed Rs for 0.05 seconds while the adsorption step S1 is performed, and then rested until the remaining time of two cycles elapses Repeat the action to Thus, at the end of 100 cycles, which is the total number of cycles, the wafer W makes one rotation (one rotation), and for example, the position of the notch N returns to the original position.

  Thus, in the film forming process, when the mounting table 21 is rotated by the rotation angle θ in the time zone of step Sp (suction step S1), the circumferential position of the wafer W when step Sp is performed is sequentially displaced. Do. Then, by performing this operation one cycle at a time, the film thickness distribution at each rotational position is superimposed, and at the end of film formation, the wafer W is in a state of N rotations (one rotation). As a result, in the step of affecting the in-plane distribution in the circumferential direction of the film thickness, even if the processing locally progresses in the plane of the wafer W, the uniformity of the in-plane distribution in the circumferential direction of the film thickness Is improved.

  As an example, an example in which the film thickness locally increases will be described schematically with reference to FIG. FIG. 4 shows that the wafer W rotates once in 10 cycles, where N is 1 and the number of repetitions M is 10 for convenience of illustration. 4 (a) shows the state when one cycle is completed without rotating the wafer W, FIG. 4 (b) shows the state when the wafer W is rotated and two cycles are completed, and FIG. 4 (c) is ten cycles completed. It is a state of time.

  FIG. 4A shows a state where a region 71 with a large film thickness is locally formed at the position P1 of 0 degree in the circumferential direction when the wafer W is not rotated and is carried out for one cycle. On the other hand, when the wafer W is rotated while the suction step S1 of each cycle is being performed, the circumferential position of the wafer W when the suction step S1 is performed is sequentially displaced as shown in FIG. 4B. Do. In this example, when the film is rotated by the rotation angle θ in the first cycle, the region 71 with a large film thickness is dispersed into a sector-shaped region 72 formed over the position P1 moved from the position P0 by the rotation angle θ.

  Thus, the area 71 with a large film thickness is dispersed into the fan-shaped area 72 also between the position P1 and the position P2 moved by the rotational angle θ in the next second cycle. Similarly, by rotating only at the rotation angle θ in the suction step S1, the area 71 with a large film thickness is dispersed into the fan-shaped area 72 also at the position P2 to the position P3... The position P9 to P0. As a result, as schematically shown, as shown in FIG. 4C, the region 71 with a large film thickness becomes annular, and the uniformity in the circumferential direction becomes high.

  Assuming that the average rotational speed Rs is determined using the step time tp of the replacement step and the wafer W is rotated in the replacement step, the film thickness is large because the replacement step is not a step that affects the film thickness. The area is formed as an area 73 surrounded by a dotted line shown in FIG. 4 (b). For this reason, although the uniformity of the film thickness in-plane distribution in the circumferential direction is improved as compared with the case where the process is performed without rotating the wafer W, the wafer W is rotated in the step of affecting the film thickness. By comparison, the uniformity is inferior.

  According to the above-described embodiment, one cycle including the respective steps of adsorption of the source gas, substitution of the processing atmosphere, and generation of a reaction product by reaction of the source gas and the reaction gas is repeated multiple times to obtain the target film thickness. When forming a film, the mounting table 21 is intermittently rotated at an average rotation speed Rs every cycle so that the mounting table 21 rotates N times. The average rotation speed Rs is determined based on the step time tp of the step Sp having the shortest step time among the steps affecting the film thickness in-plane distribution in the circumferential direction, and the time zone in which the step Sp is performed is The mounting table 21 is rotated in the included time zone. Therefore, the circumferential position of the wafer W when step Sp is performed is sequentially displaced, the film thickness distribution at each position is superimposed, and the substrate is rotated N times at the end of the film formation. As a result, the uniformity of the circumferential in-plane distribution in the film thickness is improved.

  If the raw material gas and the reactive gas can not react sufficiently due to the shortening of the process time, or the difference in the raw material supply amount with time between the central portion and the peripheral portion of the wafer W, the plasma reaction due to the nonuniform electric field The film thickness may be locally different in the wafer surface due to the difference of Even when the characteristic film thickness distribution is formed as described above, the uniformity of the in-plane distribution in the circumferential direction in the film thickness is improved by adopting the method of the above-described embodiment.

  Further, among the steps having an influence on the in-plane distribution in the circumferential direction in the film thickness, the average rotation speed Rs is set based on the step time tp of the step Sp having the shortest step time. Thereby, the area affected by the step having the shortest step time is shifted in the circumferential direction of the wafer W, and the wafer W is rotated N times until the film forming process is completed, thereby ensuring uniformity in the circumferential direction. . Therefore, in the step where the step time is longer than tp, since the affected area is wider than step Sp, when the rotation is performed at the average rotation speed Rs for each step Sp, the influence is exerted until the film forming process is completed. Since the wafer W is rotated N times with the overlapping regions, the circumferential uniformity is improved as a result.

  In the above embodiment, the mounting table 21 is rotated at a constant speed, but at least one of acceleration and deceleration may be performed while the mounting table 21 is rotating. For example, in a time zone including at least a part during the execution of step Sp, the average rotation speed of the mounting table from when the step Sp is started to when the mounting table 21 stops may be Rs. For this reason, for example, while rotating the wafer W at the rotation angle θ during one cycle, the rotation speed of the wafer W may be accelerated (or decelerated) so that the average rotation speed becomes Rs. 5 starts the rotation of the mounting table 21 at the start of the suction step S1, accelerates the rotation of the wafer W in the middle of the suction step S1, and then proceeds to the second replacement step S2 after the suction step S1. In this example, the wafer W is rotated at a constant speed, and the rotation of the wafer W is decelerated and stopped in the middle of the second replacement step S2.

  Also in this example, as described above, N = 1, the number of repetitions M is 100, and the average rotation speed Rs is set to 12 rpm based on the step time tp (0.05 seconds) of the adsorption step S1. Wafer W rotates by 360 degrees × 1/100 = 3.6 degrees from the adsorption step S1 to the second replacement step S2 when the first cycle starts, and thereafter, the remaining time of one cycle is Pause until elapsed. At this time, the average rotation speed Rs of the mounting table 21 from when the adsorption step S1 is started to when the mounting table 21 stops is set to 12 rpm.

  In the film forming process in which one cycle described above is repeated, the control waveform of the adsorption step S1 and the supply state of the source gas to the processing regions A1 and A2 may not necessarily coincide with each other. For example, there is a time lag from when the valve V1 is opened to when the gas actually reaches the wafer W. Therefore, as described above, the wafer W is rotated from the suction step S1 to the second replacement step S2, and the rotational speed is changed between them, so that the uniformity of the in-plane distribution in the circumferential direction in the film thickness is obtained. May be improved.

  Furthermore, as shown in FIG. 6A, for example, in a time zone including at least a part during the execution of step Sp, for example, after rotating the wafer W once at high speed, it is moved by θ at low speed. Good. In this case, the average rotation speed of the mounting table from when the step Sp is started to when the mounting table 21 stops may be Rs. Further, as shown in FIG. 6B, for example, in a time zone including at least a part during the execution of step Sp, for example, after rotating the wafer W once or more at high speed, it is rotated in the reverse direction. In this way, as a result, the average rotation speed of the mounting table may be Rs from the movement start time point by θ, and from when the step Sp is started to when the mounting table 21 stops. Ps in FIG. 6 is a position when the rotation of the mounting table 21 is started, and Pe is a position when the rotation is stopped.

  Furthermore, since the mounting table 21 may be rotated in a time zone including at least a part during the execution of the step Sp, the mounting table 21 rotates in a part of the time during the step Sp. You may do so. For example, the rotation may be started while the step Sp is being performed, or the rotation may be stopped while the step Sp is being performed.

  Furthermore, instead of rotating the mounting table 21 by the rotation angle θ every step Sp, while the step Sp (the step having the shortest step time among the steps having an influence on the in-plane distribution of the film thickness) is performed. For example, the mounting table 21 may be rotated N (an integer of 1 or more) at time tp including a time zone of 80% or more. In this example, the wafer W rotates N times each time a step Sp having an influence on the in-plane distribution in the circumferential direction is performed in each cycle, so the process proceeds with high uniformity in the circumferential direction in the step Sp. The uniformity of the circumferential in-plane distribution in the film thickness is improved. A time including, for example, a time zone of 80% or more while Step Sp is being performed, even if the time when Step Sp is being performed and the timing of rotating the mounting table 21 N times do not completely coincide (100%) If the mounting table 21 is rotated N at tp, the in-plane uniformity in the circumferential direction can be sufficiently improved.

  In addition, at the time tp including the already described time zone of each cycle, if the rotation speed is to rotate the mounting table 21 N times, the next cycle is started after rotating the mounting table 21 as described above. The mounting table 21 may continue to rotate at the rotation speed even if it does not stop until it reaches the end. That is, in this example, the mounting table 21 is rotated at the rotational speed from the start to the end of the film forming process.

  The film forming apparatus of the present invention is not limited to the above-described configuration, and may be applied to a single wafer type film forming apparatus having one mounting table in one processing container. Furthermore, in the step of reacting the source gas adsorbed on the wafer W with the reaction gas to generate a reaction product, the source gas and the reaction gas are reacted using thermal energy in a state where the reaction gas is supplied to the substrate. It may be a step. Furthermore, the supply of the source gas, the replacement gas, and the reaction gas may be switched to the inside of the processing container 10 without constantly supplying the replacement gas and the reaction gas as in the above-described example.

DESCRIPTION OF SYMBOLS 1 film-forming apparatus 10 processing container 21 mounting base 22 drive mechanism 33 high-frequency power supply 4 gas shower head 5 gas supply path 51 source gas source 52 source for substitution gas 53 source for reaction gas source W semiconductor wafer S1 adsorption step S2 1 substitution step S3 reaction step S4 second substitution step

Claims (11)

One cycle including a step of adsorbing the source gas on the substrate, a step of replacing the processing atmosphere with the replacement gas, and a step of reacting the source gas adsorbed on the substrate with the reaction gas to generate a reaction product is repeated several times In a film forming apparatus for laminating reaction products on a substrate,
A processing container for placing a substrate mounting table therein and forming a vacuum processing atmosphere;
A rotation mechanism for rotating the mounting table;
A control unit that controls the rotation mechanism;
The control unit
Assuming that the number of repetitions of one cycle is M, the table is intermittently rotated by an angle represented by 360 degrees × {N (an integer of 1 or more) / M}.
Among the steps that affect the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle, let Sp be the step with the shortest step time required for the step, and tp be the step time of the step Sp. And outputting a control signal to rotate the mounting table in a time zone including at least a part while the step Sp is being performed,
An average rotation speed Rs of the mounting table from when the step Sp is started to when the mounting table stops is represented by Rs = (N / M) × (1 / tp).   The film forming apparatus according to claim 1, wherein a rotation start time of the mounting table is a start time of the step Sp.   The film forming apparatus according to claim 1, wherein the mounting table starts rotating while the step Sp is being performed.   The time zone including at least a part during the execution of the step Sp is a time zone including 30% or more during the execution of the step Sp. Film forming apparatus.   The film forming apparatus according to any one of claims 1 to 4, wherein the mounting table rotates at a constant speed.   The film forming apparatus according to any one of claims 1 to 5, wherein at least one of acceleration and deceleration is performed during rotation of the mounting table. One cycle including a step of adsorbing the source gas on the substrate, a step of replacing the processing atmosphere with the replacement gas, and a step of reacting the source gas adsorbed on the substrate with the reaction gas to generate a reaction product is repeated several times In a film forming apparatus for laminating reaction products on a substrate,
A processing container for placing a substrate mounting table therein and forming a vacuum processing atmosphere;
A rotation mechanism for rotating the mounting table;
A control unit that controls the rotation mechanism;
Among the steps affecting the in-plane distribution in the circumferential direction in the film thickness of the thin film on the substrate, the control unit Sp in the one cycle is a step having the shortest step time required for the step Sp, the step of the step Sp Assuming that the time is tp, a control signal is output so as to rotate the mounting table N (an integer of 1 or more) at time tp including a time zone of 80% or more while the step Sp is performed. The film-forming apparatus characterized by being.   The film forming apparatus according to any one of claims 1 to 7, wherein the step Sp is a step of adsorbing the source gas to the substrate.   The step of reacting the source gas adsorbed on the substrate with the reaction gas to generate a reaction product is a step of plasmatizing the reaction gas in a state where the reaction gas is supplied to the substrate, and the step Sp is the reaction The film forming apparatus according to any one of claims 1 to 7, which is a step of plasmatizing a gas. In the vacuum processing atmosphere, the step of adsorbing the source gas on the substrate placed on the mounting table, the step of replacing the processing atmosphere with the replacement gas, and the reaction of the source gas adsorbed on the substrate with the reaction gas Forming a reaction product on the substrate by repeating one cycle including the step of generating a plurality of times;
Intermittently rotating the table by an angle represented by 360 degrees × {N (an integer of 1 or more) / M}, where M represents the number of repetitions of one cycle.
In the step of intermittently rotating the mounting table, one of the steps affecting the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle has the shortest step time required for the step. Sp, assuming that the step time of the step Sp is tp, is a step of rotating the mounting table in a time zone including at least a part while the step Sp is being performed,
An average rotational speed Rs of the mounting table from when the step Sp is started to when the mounting table is stopped is represented by Rs = (N / M) × (1 / tp). In the vacuum processing atmosphere, the step of adsorbing the source gas on the substrate placed on the mounting table, the step of replacing the processing atmosphere with the replacement gas, and the reaction of the source gas adsorbed on the substrate with the reaction gas Forming a reaction product on the substrate by repeating one cycle including the step of generating a plurality of times;
Among the steps that affect the circumferential in-plane distribution of the film thickness of the thin film on the substrate in the one cycle, let Sp be the step with the shortest step time required for the step, and tp be the step time of the step Sp. A film forming method comprising rotating the mounting table N (an integer of 1 or more) at a time tp including a time zone of 80% or more while the step Sp is performed.

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