JP6919498B2 - Film formation equipment and film formation method - Google Patents

Description

The present invention relates to a technique for laminating a reaction product on a substrate by repeating a cycle of reacting a raw material gas adsorbed on the substrate with a reaction gas to generate a reaction product.

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

In this device, the raw material gas is adsorbed on the wafer, and the reaction gas is supplied in parallel with the supply of the raw material gas, for example, and plasma is intermittently formed to activate the reaction gas to the active species of the reaction gas and the wafer. A reaction product is produced by reacting with the adsorbed raw material gas. Then, a thin film having a desired film thickness is formed by repeating a plurality of cycles in which the step of supplying the raw material gas and the step of reacting the raw material gas with the reaction gas are alternately performed. In the dry etching process, which is the next process, the etching rate is often adjusted concentrically. Therefore, in such an ALD process, a film thickness profile that makes the film thickness in the circumferential direction uniform in the wafer surface. You may be required to control.

That is, if the film thickness uniformity in the circumferential direction is good, the convex shape in which the film thickness in the central portion is larger than that in the peripheral portion when viewed in the radial direction of the wafer, or the film thickness in the central portion is the peripheral portion. Even if the concave shape is smaller than that of the above, the film thickness distribution in the radial direction can be smoothed in the subsequent dry etching step. However, in the ALD process, the process may proceed locally in the wafer surface in a specific step, resulting in variations in film thickness.

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 when the substrate placed on the rotary table is revolved to perform the ALD process. ing. Further, in Patent Document 3, when a boat holding a substrate 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 cycle and the wafer rotation cycle are described. A technique for improving the in-plane uniformity of the film thickness by controlling the film thickness so as not to synchronize is described. However, Patent Documents 1 to 3 do not focus on the progress of local processing in a specific step, and cannot solve the problem of the present invention.

Japanese Unexamined Patent Publication No. 2016-92156 Japanese Unexamined Patent Publication No. 2016-20602 International Publication WO2005 / 088692

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

The present invention includes one cycle including a step of adsorbing a raw material gas on a substrate, a step of replacing a processing atmosphere with a replacement gas, and a step of reacting the raw material 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 it a plurality of times.
A substrate mounting table is placed inside the substrate, and a processing container for forming a vacuum processing atmosphere and a processing container.
A rotation mechanism for rotating the above-mentioned stand and
A control unit that controls the rotation mechanism is provided.
The control unit
Assuming that the number of repetitions of the one cycle is M, the above-mentioned stand is intermittently rotated by an angle represented by 360 degrees × {N (integer of 1 or more) / M}.
In the one cycle, among the steps affecting the in-plane distribution of the film thickness of the thin film on the substrate in the circumferential direction, the step with the shortest step time required for the step is Sp, and the step time of the step Sp is tp. , The control signal is configured to rotate the mounting table during a time period including at least a part of the step Sp.
The average rotation speed Rs of the mounting table from the time when the step Sp is started until the mounting table is stopped is represented by Rs = (N / M) × (1 / tp).

Further, in the present invention, in a vacuum processing atmosphere, a step of adsorbing a raw material gas on a substrate placed on a mounting table, a step of replacing the processing atmosphere with a replacement gas, and a reaction between the raw material gas adsorbed on the substrate and the reaction gas. A film forming step of laminating the reaction product on the substrate by repeating one cycle a plurality of times including a step of forming the reaction product by causing the reaction product to be formed.
Assuming that the number of repetitions of the one cycle is M, the step of intermittently rotating the above-mentioned stand by an angle represented by 360 degrees × {N (integer of 1 or more) / M} is included.
The step of intermittently rotating the pedestal described above is the step in which the step time required for the step is the shortest among the steps that affect the in-plane distribution of the film thickness of the thin film on the substrate in the circumferential direction in the above one cycle. Assuming that Sp and the step time of the step Sp are tp, it is a step of rotating the mounting table in a time zone including at least a part while the step Sp is being performed.
The average rotation speed Rs of the mounting table from the time when the step Sp is started until the mounting table is stopped is represented by Rs = (N / M) × (1 / tp).

In the present invention, when one cycle including each step of adsorption of raw material gas, replacement of treatment atmosphere, and generation of reaction product by reaction between raw material gas and reaction gas is repeated a plurality of times to form a film with a target film thickness. In addition, the mounting table is intermittently rotated every cycle so that the mounting table of the substrate 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 in-plane distribution of the film thickness in the circumferential direction, and the step Sp is performed. Rotate the mounting table in the time zone including the time zone. Therefore, the position in the circumferential direction of the substrate when the step Sp is performed is sequentially displaced, the film thickness distributions at each position are overlapped, and the substrate is in a state of N rotation at the end of film formation. As a result, the uniformity of the in-plane distribution in the circumferential direction in the film thickness is improved.

Further, in the other invention of the present invention, among the steps affecting the in-plane distribution in the circumferential direction in the film thickness of the thin film on the substrate in the one cycle, the step Sp having the shortest step time required for the step is performed. The mounting table is rotated by N (an integer of 1 or more) at a time tp including a time zone of 80% or more during the period. Therefore, since the substrate rotates N every time the 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 which shows the film forming apparatus which concerns on embodiment of this invention. It is a schematic perspective view of a film forming apparatus. It is a chart figure which shows the film forming method carried out by a film forming apparatus. It is a top view explaining the operation of the film forming apparatus. It is a chart figure which shows the other film-forming method carried out by a film-forming apparatus. It is a top view which shows the other film forming method carried out by a film forming apparatus.

An example of the film forming apparatus according to the embodiment of the present invention applied to a film forming apparatus for forming a film on a wafer W by plasma ALD (Atomic Layer Deposition) will be described. For example, the film forming apparatus 1 includes a processing container 10 having a rectangular cross section as shown in FIG. In the figure, 101 is a ceiling member of the processing container 10, and 102 is a container body. A carry-in outlet 11 for loading and unloading the wafer W is formed on the side wall of the processing container 10, and the carry-in outlet 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 on the front side and the back side when viewed from the carry-in outlet 11. An exhaust port 15 for exhausting the atmosphere inside 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 a vacuum exhaust mechanism via an exhaust pipe 16. There is. FIG. 18 in FIG. 1 is a pressure adjusting unit that adjusts the pressure inside the processing container 10.

Since the substrate processing units 13 and 14 are configured in the same manner as each other, the substrate processing unit 13 will be described as an example. As shown in FIG. 1, the substrate processing unit 13 includes a mounting table 21 on which the wafer W is mounted. The mounting table 21 also serves as a lower electrode. For example, it is formed in a flat columnar shape made of a metal such as aluminum or nickel, and can be moved up and down and vertically via a drive shaft 221 by a drive mechanism 22 that also serves as a rotation mechanism. It is configured to rotate around.

In FIG. 1, the mounting table 21 at the processing position is drawn with a solid line, and the mounting table 21 at the delivery position is shown with a dotted line. The processing position is a position when the film forming process described later is executed, and the transfer position is a position where the wafer W is transferred to and 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 the wafer W is configured to be heated to, for example, about 300 ° C. to 450 ° C. Further, the mounting table 21 is connected to the ground potential via a matching device (not shown).

Further, on the upper side of the substrate processing unit 13 and 14, via the insulating member 31, a metal gas shower head 4 constituting the upper electrode that provided. The gas shower head 4 of this high-frequency power source 33 is connected via a matching unit 32. In this way, the film forming apparatus 1 is configured as a parallel plate type plasma processing apparatus in which high frequency power is applied between the gas shower head 4 and the mounting table 21 to generate plasma.

The gas shower head 4 is formed of a lid 41, a shower plate 42 provided so as to face the mounting surface of the mounting table 21, and a flat gas formed between the lid 41 and the shower plate 42. It is provided with a flow chamber 43. A gas supply path 5 is connected to the lid 41, and gas supply holes 44 penetrating in the thickness direction are arranged in the shower plate 42 in the vertical and horizontal directions, for example, and the gas is directed toward the mounting table 21 in a shower shape. Be 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 raw material gas supply source 51, a replacement gas supply source 52, and a reaction gas supply source 53. In FIG. 1, V1 to V3 are valves, and C1 to C3 are flow rate adjusting units. As the raw material gas, for example, a gas containing silicon (Si) such as Si2Cl6, Si2H6, HCDS (hexachlorodisilane), TDMAS (tridimethylaminosilane), BDEAS (bisdiethylaminosilane) is used. As the reaction gas, an oxidizing gas or a reducing gas is used depending on the application. For example, as the oxidizing gas, oxygen (O2) gas, ozone (O3) gas or the like can be used. As the replacement gas, for example, an inert gas such as argon (Ar) gas is used.

Further, on the bottom surface of the processing container 10, a plurality of, for example, three delivery pins 20 are provided at positions corresponding to each mounting table 21, while the mounting table 21 forms a passing region for the delivery pins 20. Through hole 24 is 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 projects from the mounting surface of the mounting table 21. In this way, the wafer W is delivered between the transport mechanism and each mount 21 by the cooperative action of the external transport mechanism (not shown), the transfer pin 20, and the mounting table 21. Reference numeral 25 in FIG. 1 is a sealing member for keeping the inside of the processing container 10 airtight.

Further, as shown in FIGS. 1 and 2, 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 each of the substrate processing units 13 and 14. In order to form the processing areas A1 and A2, a partition member 26 made of an insulating member is provided. The partition member 26 is formed so as to surround the processing areas A1 and A2, respectively, and an opening 261 for delivering the substrate to the mounting table 21 of the substrate processing portions 13 and 14 is formed by an external transfer mechanism. ..

FIG. 2 schematically shows a configuration in which two film forming devices 1 provided with substrate processing units 13 and 14 are connected, and one film forming device 1 is provided with a lid 41 of a 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 shows a state in which the mounting table 21 is arranged at 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 replacement step S2, the reaction step S3, and the second replacement step S4 a plurality of times, for example, 100 times. In FIG. 3, the step time (time during which the step is performed) of each step S1 to S4 is t1 to t4.

The adsorption step S1 is a step of adsorbing the raw material gas on the wafer W, and the first replacement step S2 is a step of replacing the atmosphere of the processing regions A1 and A2, which is the processing atmosphere, with the replacement gas. The reaction step S3 is a step of reacting the raw material gas adsorbed on the wafer W with the reaction gas to generate a reaction product, and the second replacement step S4 is the processing regions A1 and A2 before supplying the raw material gas. This is a step of replacing the atmosphere of the above with a replacement gas. Then, by repeating one cycle consisting of steps S1 to S4 a set number of times, a layer of a silicon oxide film which is a reaction product is laminated on the surface of the wafer W to form a SiO2 film having a predetermined film thickness. ..

The film forming apparatus 1 is provided with a control unit 6 including a computer. The control unit 6 includes, for example, a data processing unit including a program, a memory, and a CPU. The program incorporates instructions so that a control signal can be sent from the control unit 6 to each unit of the film forming apparatus 1 to execute the film forming process described above. 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, a hard disk, or an MO (magneto-optical disk) and installed in the control unit 6.

The program also includes a program that controls 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 the film forming process. ing. The average rotation speed Rs is a speed obtained by the following equation (1).
Rs = (N / M) × (1 / tp) ・ ・ ・ (1)

In the formula (1), tp is the shortest step time required for the step among the steps that affect the in-plane distribution of the film thickness of the thin film on the wafer W in the circumferential direction in one cycle of the film forming process. This is the step time of step Sp. The number of times the film formation cycle is repeated M is determined by the target film thickness (Å) and the film formation rate per cycle (Å / cycle). Further, 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 the time when the step Sp is started until the mounting table 21 is stopped. It is configured to control the average rotation speed of the mounting table 21 to be Rs. The time zone including at least a part while the step Sp is being performed is a time zone including 30% or more while the step Sp is being performed, and is preferably a time zone including 50% or more. Further, a more preferable operation is an operation in which the mounting table 21 starts rotating at the same time as 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 will rotate in 100% of the time zone while the step Sp is being performed.

Here, in one cycle of the film forming process, the steps that affect the in-plane distribution of the thin film on the wafer W in the circumferential direction are, in this example, the adsorption step S1 for adsorbing the raw material gas on the wafer W. The reaction step S3 is a reaction step S3 of reacting the raw material gas adsorbed on the wafer W with the reaction gas to produce a reaction product. Comparing the step time t1 of the adsorption step S1 and the step time t3 of the reaction step S3, since the step time t1 is shorter, the step Sp is the adsorption step S1 and the tp is the step time of the adsorption step S1.

Specifically, the case where the rotation start time of the mounting table 21 is the start time of the step Sp (adsorption step S1) and the mounting table 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 the equation (1). Further, the rotation angle θ of the mounting table 21 is 3.6 degrees from 360 degrees × (1/100).

In this way, 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 the rotation angle θ at 12 rpm at the start of the adsorption step S1. As a result, the wafer W has an average rotation speed Rs, in this case, a constant velocity rotation speed, for the rotation angle θ (3.6 degrees) during the step time tp (0.05 seconds) of the suction step S1 for each cycle. It rotates at Rs (12 rpm) and stops rotating during the other steps S2 to S4. In this way, the wafer W is controlled to rotate N (1 rotation) when the number of repetitions M is executed, that is, when the target film thickness is reached.

For example, the average rotation speed Rs is written in the recipe for the film forming process together with the number of cycle repetitions M and N, the step Sp, and the step time tp. By selecting the recipe stored in the memory, the mounting table 21 can be set. A control signal is output to rotate. Further, the control unit 6 may be provided with a display unit so that the step time can be appropriately changed via the display unit. In this case, for example, a step (in this example, adsorption step S1 and reaction step S3) that affects the in-plane distribution of the film thickness in the circumferential direction is specified in advance in the recipe, and the step Sp with the shortest step time is specified. The average rotation speed Rs may be calculated based on the automatic comparison and selection, and the control signal may be output so as to rotate the mounting table 21 using this data.

Subsequently, the film forming process of the wafer W performed by the film forming apparatus 1 will be described. First, the inside of the processing container 10 is set to a predetermined vacuum atmosphere, the gate valve 12 is opened in a state where the two mounting tables 21 are positioned at the delivery positions, and the transfer mechanism is used from the transfer chamber having a vacuum atmosphere adjacent to the processing container 10, for example. The two wafers W are simultaneously delivered to the delivery pins 20 protruding from the respective mounting bases 21. When the wafer W is delivered to the mounting table 21 by raising and lowering the mounting table 21 and exiting from the processing container 10 of the transport mechanism, the gate valve 12 is closed, the mounting table 21 is raised to the processing position, and the processing area A1 , A2 is formed. 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 supplying the replacement gas and the valve V3 for supplying the reaction gas are opened, respectively, and Ar gas is opened from the replacement gas supply source 52 and O2 gas is opened from the reaction gas supply source 53, respectively. Is supplied to the processing areas A1 and A2. Subsequently, the valve V1 for supplying the raw material gas is opened, and the raw material gas supply source 51 discharges the raw material gas into the processing regions A1 and A2 via the gas shower head 4, and the raw material gas molecule (silicon atom which is a silicon precursor) is discharged onto the wafer W. (Material containing) is adsorbed (adsorption step S1). During the step time tp (0.05 seconds) of the adsorption step S1, the wafer W is rotated at 12 rpm, which is a preset average rotation speed Rs (here, constant velocity rotation speed Rs).

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

Next, the high frequency power supply 33 is turned on. At this time, O2 gas and Ar gas are supplied to the processing regions A1 and A2, and by applying high frequency power, the O2 gas in the processing regions A1 and A2 is converted into plasma, which is adsorbed on the wafer W by the plasma. The raw material gas is oxidized to form a layer of silicon oxide as a reaction product (reaction step S3). Next, by turning off the high-frequency power supply 33 and continuing to supply Ar gas, the active species of plasma remaining in the processing regions A1 and A2 are purged into Ar gas, and from the processing regions A1 and A2. Remove (second replacement step S4).

After that, the valve V1 is opened again to supply the raw material gas, and the adsorption step S1 is executed while rotating the wafer W at the rotation speed Rs. Subsequently, four steps of the first replacement step S2, the reaction step S3, and the second replacement step S4 are performed, and the film forming cycle consisting of steps S1 to S4 is repeated 100 times, which is the number of repetitions M, to obtain the wafer. A SiO2 film having a target thickness is formed on the surface of W.

As described above, when the first cycle is started, the wafer W has a rotation angle θ (12 rpm) at a constant rotation speed Rs (12 rpm) during 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, it rotates by the rotation angle θ at the rotation speed Rs during 0.05 seconds while the suction step S1 is being performed, and then pauses until the remaining time of the two cycles elapses. The operation of doing is repeated. In this way, at the end of 100 cycles, which is the total number of cycles, the wafer W makes one rotation (one turn), and for example, the position of the notch N returns to the initial position.

As described above, in the film forming process, when the mounting table 21 is rotated by the rotation angle θ in the time zone of step Sp (adsorption step S1), the position in the circumferential direction of the wafer W when step Sp is performed is sequentially displaced. do. By performing this operation one cycle at a time, the film thickness distributions at each rotation position are superposed, and the wafer W is in a state of N rotations (1 rotation) at the end of film formation. As a result, in the step that affects the in-plane distribution of the film thickness in the circumferential direction, even if the treatment proceeds locally in the in-plane of the wafer W, the uniformity of the in-plane distribution in the circumferential direction in the film thickness Is improved.

As an example thereof, an example in which the film thickness is locally increased will be schematically described with reference to FIG. FIG. 4 shows how the wafer W makes one rotation in 10 cycles, where N is 1 and the number of repetitions M is 10 for convenience of illustration. FIG. 4 (a) shows a state when one cycle is completed without rotating the wafer W, FIG. 4 (b) shows a state when two cycles are completed by rotating the wafer W, and FIG. 4 (c) shows a state when 10 cycles are completed. The state of time.

FIG. 4A shows a state in which a region 71 having a large film thickness is locally formed at a position P1 at 0 degrees in the circumferential direction when one cycle is performed without rotating the wafer W. On the other hand, when the wafer W is rotated while the suction step S1 of each cycle is performed, the position in the circumferential direction of the wafer W when the suction step S1 is performed is sequentially displaced as shown in FIG. 4 (b). do. In this example, when the rotation angle θ is rotated in the first cycle, the region 71 having a large film thickness is dispersed in the fan-shaped region 72 formed over the position P1 moved from the position P0 by the rotation angle θ.

In this way, the region 71 having a large film thickness is dispersed in the fan-shaped region 72 even between the positions P2 moved from the position P1 by the rotation angle θ in the next second cycle. Similarly, by rotating the suction step S1 by the rotation angle θ, the region 71 having a large film thickness is dispersed in the fan-shaped region 72 also at positions P2 to position P3 ... Positions P9 to P0. As a result, to put it roughly, as shown in FIG. 4C, the region 71 having a large film thickness becomes annular, and the uniformity in the circumferential direction is improved.

If the average rotation speed Rs is obtained by using the step time tp of the replacement step and the wafer W is rotated in the replacement step, the replacement step is not a step that affects the film thickness, so that the film thickness is large. The region is formed as shown in the region 73 surrounded by the dotted line shown in FIG. 4 (b). Therefore, as compared with the case where the process is performed without rotating the wafer W, the uniformity of the in-plane distribution of the film thickness in the circumferential direction is improved, but when the wafer W is rotated in a step that affects the film thickness. By comparison, the uniformity is inferior.

According to the above-described embodiment, one cycle including each step of adsorbing the raw material gas, replacing the treatment atmosphere, and generating the reaction product by the reaction between the raw material gas and the reaction gas is repeated a plurality of times to reach the target film thickness. The mounting table 21 is intermittently rotated at an average rotation speed Rs for each cycle so that the mounting table 21 rotates N times when the film is formed. The average rotation speed Rs is obtained based on the step time tp of the step Sp having the shortest step time among the steps affecting the in-plane distribution of the film thickness in the circumferential direction, and the time zone in which the step Sp is performed is determined. The mounting table 21 is rotated during the including time zone. Therefore, the position in the circumferential direction of the wafer W when the step Sp is performed is sequentially displaced, the film thickness distributions at each position are overlapped, and the substrate is in a state of N rotation at the end of film formation. As a result, the uniformity of the in-plane distribution in the circumferential direction in the film thickness is improved.

When the raw material gas and the reaction gas cannot sufficiently react due to the shortened process time, the difference in the amount of raw material supplied over time between the central portion and the peripheral portion of the wafer W, and the plasma reaction due to the non-uniform electric field. The film thickness may be locally different in the wafer surface due to the difference between the two. Even when such a characteristic film thickness distribution is formed, 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, the average rotation speed Rs is set based on the step time tp of the step Sp, which has the shortest step time among the steps that affect the in-plane distribution in the circumferential direction in the film thickness. As a result, the region 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 by N until the film forming process is completed to ensure uniformity in the circumferential direction. .. Therefore, in a step in which the step time is longer than tp, the affected region is wider than that in step Sp. Therefore, if the rotation speed Rs is rotated for each step Sp, the effect is exerted by the time the film forming process is completed. Since the wafer W is rotated N times in a state where the regions overlap, the uniformity in the circumferential direction is improved as a result.

In the above-described embodiment, the mounting table 21 is rotated at a constant speed, but at least one of acceleration and deceleration may be performed during the rotation of the mounting table 21. For example, the average rotation speed of the mounting table from the time when the step Sp is started to the time when the mounting table 21 is stopped may be Rs in a time zone including at least a part while the step Sp is being performed. Therefore, 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. FIG. 5 shows that the rotation of the mounting table 21 is started at the start of the suction step S1, the rotation of the wafer W is accelerated in the middle of the suction step S1, and then the second replacement step S2 after the suction step S1 is performed. This is an example in which the wafer W is rotated at a constant speed, the rotation of the wafer W is decelerated and stopped in the middle of the second replacement step S2.

In this example as well, N = 1, the number of repetitions M is set to 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 as described above. When the first cycle starts, the wafer W is rotated by 360 degrees × 1/100 = 3.6 degrees from the suction step S1 to the second replacement step S2, and then the remaining time of one cycle is reached. Pause until it elapses. At this time, the average rotation speed Rs of the mounting table 21 from the time when the suction step S1 is started until the mounting table 21 is stopped is set to 12 rpm.

In the film forming process in which the above-mentioned one cycle is repeated, the control waveform of the adsorption step S1 and the supply state of the raw material gas to the processing regions A1 and A2 may not always match. For example, there is a time lag between the opening of the valve V1 and the actual arrival of the gas at the wafer W. Therefore, as described above, the wafer W is rotated from the adsorption step S1 to the second replacement step S2, and the rotation speed is changed between them, so that the uniformity of the in-plane distribution in the circumferential direction in the film thickness is uniform. May be improved.

Further, as shown in FIG. 6A, for example, in a time zone including at least a part while step Sp is being performed, for example, the wafer W may be made to go around at high speed and then moved by θ at low speed. good. In this case, the average rotation speed of the mounting table from the time when step Sp is started until the mounting table 21 is stopped may be Rs. Further, as shown in FIG. 6B, for example, in a time zone including at least a part while step Sp is being performed, for example, the wafer W is rotated at a high speed for one or more turns and then rotated in the opposite direction. As a result, the average rotation speed of the mounting table from the time when the step Sp is started to the time when the mounting table 21 is stopped may be Rs. In FIG. 6, Ps 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 during a time period including at least a part of the time during which the step Sp is being performed, the mounting table 21 is rotated during a part of the time during which the step Sp is being performed. You may do so. For example, the rotation may be started in the middle of the step Sp, or the rotation may be stopped in the middle of the step Sp.

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

Further, if the rotation speed is such that the mounting table 21 is rotated by N in the time tp including the above-mentioned time zone of each cycle, 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 is not stopped until. That is, in this example, the mounting table 21 rotates at the rotation 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 film forming apparatus provided with one mounting table in one processing container. Further, in the step of reacting the raw material gas adsorbed on the wafer W with the reaction gas to generate a reaction product, the raw material gas and the reaction gas are reacted using heat energy while the reaction gas is supplied to the substrate. It may be a step. Further, instead of constantly supplying the replacement gas and the reaction gas as in the above example, the supply of the raw material gas, the replacement gas, and the reaction gas may be switched to the inside of the processing container 10.

1 Formation apparatus 10 Processing container 21 Mounting table 22 Drive mechanism 33 High-frequency power supply 4 Gas shower head 5 Gas supply path 51 Raw material gas supply source 52 Substitution gas supply source 53 Reaction gas supply source W Semiconductor wafer S1 Adsorption step S2 First Substitution step S3 Reaction step S4 Second substitution step

Claims (9)

One cycle including the step of adsorbing the raw material gas on the substrate, the step of replacing the processing atmosphere with the replacement gas, and the step of reacting the raw material gas adsorbed on the substrate with the reaction gas to generate a reaction product is repeated a plurality of times. In a film forming apparatus for laminating a reaction product on a substrate,
A substrate mounting table is placed inside the substrate, and a processing container for forming a vacuum processing atmosphere and a processing container.
A rotation mechanism for rotating the above-mentioned stand and
A control unit that controls the rotation mechanism is provided.
The control unit
Assuming that the number of repetitions of the one cycle is M, the above-mentioned stand is intermittently rotated by an angle represented by 360 degrees × {N (integer of 1 or more) / M}.
In the one cycle, among the steps affecting the in-plane distribution of the film thickness of the thin film on the substrate in the circumferential direction, the step with the shortest step time required for the step is Sp, and the step time of the step Sp is tp. , The control signal is configured to rotate the mounting table during a time period including at least a part of the step Sp.
A film forming apparatus characterized in that the average rotation speed Rs of the mounting table from the time when step Sp is started until the mounting table is stopped is represented by Rs = (N / M) × (1 / tp). The film forming apparatus according to claim 1, wherein the rotation start time of the pedestal described above is the start time of the step Sp. The film forming apparatus according to claim 1, wherein the pedestal described above starts rotation from the middle of the step Sp. The first or second claim, wherein the time zone including at least a part while the step Sp is being performed is a time zone including 30% or more while the step Sp is being performed. Film forming equipment. The film forming apparatus according to any one of claims 1 to 4, wherein the stand is rotated 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 above-mentioned stand. The film forming apparatus according to any one of claims 1 to 6 , wherein the step Sp is a step of adsorbing a raw material gas on a substrate. The step of reacting the raw material gas adsorbed on the substrate with the reaction gas to generate a reaction product is a step of converting the reaction gas into plasma while 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 6 , wherein the step is a step of converting gas into plasma. In a vacuum processing atmosphere, a step of adsorbing a raw material gas on a substrate placed on a mounting table, a step of replacing the processing atmosphere with a replacement gas, and a reaction of the raw material gas adsorbed on the substrate with a reaction gas to produce a reaction product. A film forming step of laminating the reaction product on the substrate by repeating one cycle including the step of forming the reaction product a plurality of times.
Assuming that the number of repetitions of the one cycle is M, the step of intermittently rotating the above-mentioned stand by an angle represented by 360 degrees × {N (integer of 1 or more) / M} is included.
The step of intermittently rotating the pedestal described above is the step in which the step time required for the step is the shortest among the steps that affect the in-plane distribution of the film thickness of the thin film on the substrate in the circumferential direction in the above one cycle. Assuming that Sp and the step time of the step Sp are tp, it is a step of rotating the mounting table in a time zone including at least a part while the step Sp is being performed.
A film forming method characterized in that the average rotation speed Rs of the mounting table from the time when step Sp is started until the mounting table is stopped is represented by Rs = (N / M) × (1 / tp).

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