JP2016216787A - Film deposition device, film deposition method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a consumption amount of WClin a film deposition process for a wafer 100 by a material obtained by sublimation of the WCl.SOLUTION: In the film deposition process by supplying carrier gas with WClin a sublimed state to a vacuum vessel 10, when one material capture part 41 is used as a material supply source, a material in exhaust gas exhausted from the vacuum vessel 10 is captured by the other material capture part 42. When the other material capture part 42 is used as the material supply source, the material in the exhaust gas exhausted from the vacuum vessel 10 is captured by one material capture part 41. As the captured material is sublimed and reused as process gas, the consumption amount of the material is reduced. When the wafer 100 is carried into and out of the vacuum vessel 10 for lowering pressure in the vacuum vessel 10, the gas is exhausted through an exhaust pass 13 without through the material capture part, and thereby, the material is captured in the material capture part in high purity.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for performing a film forming process by sublimating a solid material and supplying it to an object to be processed.

  As a film forming process that is one of the semiconductor manufacturing processes, so-called ALD (Atomic Layer Deposition) in which a source gas and a reaction gas that oxidizes, nitrides, or reduces the source gas are alternately supplied, or the source gas is supplied in the gas phase. There is CVD (Chemical Vapor Deposition) etc. that decomposes or reacts with reaction gas. As a source gas used for such a film formation process, for example, a solid as described in Patent Document 1 is used in order to increase the density of crystals after film formation and reduce the amount of impurities taken into the substrate as much as possible. A gas obtained by sublimating the raw material may be used. For example, it is used when a high dielectric film is formed.

In the film forming apparatus, a reaction gas product of the processing gas supplied into the processing container is deposited on the surface of the substrate, and the film is formed on the substrate out of the processing gas supplied into the processing container. For example, the gas that contributes to 10% or less may be 10% or less, and most of the processing gas is exhausted.
In recent years, in order to form a complicated three-dimensional pattern on the surface of the substrate, the number of layers of films formed on the surface of the substrate has been increasing. For this reason, the area of the film formation region on the substrate is increased and the amount of processing gas used is increased, so that the amount of processing gas exhausted is also increased. For these reasons, the cost of raw materials is incurred, and the demand for curbing resource consumption is expected to increase in the future.

JP 2008-240119 A

  The present invention has been made under such circumstances. The purpose of the present invention is to reduce the amount of raw material consumed when a film is formed on an object to be processed using a raw material obtained by sublimating a solid raw material. It is to provide a technology that can be suppressed.

The film forming apparatus according to the present invention is a film forming process performed on an object to be processed by sublimating a solid raw material of a raw material supply source and supplying the solid raw material together with a carrier gas into a processing container in a vacuum atmosphere. In a film forming apparatus for performing a film forming process in which the vapor pressure of an object is higher than the vapor pressure of the raw material,
A first exhaust path for evacuating the inside of the processing container by an evacuation mechanism;
A raw material capturing portion provided in the first exhaust path for capturing the raw material in the gas;
Provided by bypassing the raw material trapping section, a carrier gas is supplied to the second exhaust path for evacuating the inside of the processing vessel by a vacuum exhaust mechanism and the raw material trapping section, and trapped by the raw material trapping section. A carrier gas supply unit for sublimating the raw material and supplying the raw material into the processing container via the raw material supply path;
A temperature adjusting unit for adjusting the temperature of the raw material capturing unit between a temperature for capturing the raw material and a temperature for sublimating the captured raw material;
When a film forming process is performed on the object to be processed using a raw material supply source other than the raw material capturing unit, vacuum exhaust is performed by the first exhaust path, and when the raw material capturing unit is used as a raw material supply source, the first exhaust channel is used. And a switching unit that switches the exhaust path so that vacuum exhaust is performed by the two exhaust paths.

The film forming method of the present invention includes a step of performing a film forming process on an object to be processed by sublimating a solid raw material of a raw material supply source and supplying the solid raw material together with a carrier gas into a processing container in a vacuum atmosphere;
While performing the step, the inside of the processing vessel is evacuated through the first exhaust passage, and the raw material capture provided at the first exhaust passage and set to a temperature for capturing the raw material Capturing the raw material in the exhaust gas in the part,
Thereafter, a step of setting the temperature of the raw material capturing unit to a temperature for sublimating the raw material,
A carrier gas is supplied to the raw material capturing unit set to a temperature for sublimating the raw material, and the raw material captured by the raw material capturing unit is sublimated and supplied into the processing container through the raw material supply path. Performing a film forming process on the processing body, and evacuating the inside of the processing container via a second exhaust path that bypasses the raw material capturing unit,
The vapor pressure of the by-product during the film forming process is higher than the vapor pressure of the raw material.

The storage medium of the present invention is a computer used in a film forming apparatus that sublimates a solid raw material as a raw material supply source and supplies it to a processing container in a vacuum atmosphere together with a carrier gas to perform a film forming process on an object to be processed. A storage medium storing a program,
The computer program includes a group of steps so as to execute the film forming method described above.

  The present invention provides an exhaust gas exhausted from a processing container when sublimating a solid material as a raw material supply source and supplying it into a processing container in a vacuum atmosphere together with a carrier gas to perform a film forming process on a target object. The raw material inside is captured and reused by the raw material capturing unit. For this reason, there exists an effect which can suppress the consumption of a raw material.

1 is an overall configuration diagram showing a film forming apparatus according to an embodiment of the present invention. It is a block diagram which shows the raw material supply system provided in the film-forming apparatus. It is a perspective view which shows a raw material capture | acquisition part. It is a top view which shows a raw material capture | acquisition part. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 1st Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 1st Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 1st Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 1st Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 2nd Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 2nd Embodiment. It is explanatory drawing explaining the effect | action of the film-forming apparatus which concerns on 2nd Embodiment.

[First embodiment]
A first embodiment of the film forming apparatus of the present invention will be described with reference to FIGS. As shown in FIG. 1, the film forming apparatus includes three film forming processing units for performing a film forming process by, for example, a so-called ALD method on an object to be processed, such as a semiconductor wafer (hereinafter referred to as “wafer”). 1A to 1C, a raw material supply system 2A to 2C for supplying a raw material gas to each of the film forming units 1A to 1C, and a common raw material for replenishing the raw material to each of the raw material supply systems 2A to 2C as described later And a tank 3. In this example, as an ALD method, an example of forming a W (tungsten) film using WCl ₆ (tungsten hexachloride) as a source gas and hydrogen (H ₂ ) as a reaction gas (reducing gas) as a processing gas is given. ing.

The raw material tank 3 is made of, for example, stainless steel, and stores solid (powder) WCl ₆ as a solid raw material (solid raw material) 300 at a normal temperature as a raw material. At the ceiling of the raw material tank 3, each of the raw material gas from the raw material tank 3 and the downstream end of the carrier gas supply path 64 into which an inert gas, for example, N ₂ (nitrogen) gas, which becomes a carrier gas flows into the raw material tank 3 An upstream end portion of a raw material replenishing pipe 30 that supplies the raw material supply systems 2A to 2C to replenish the raw material is connected. The carrier gas supply path 64 is provided with a mass flow controller 65 for adjusting the flow rate of the carrier gas, and a valve V64.

The periphery of the raw material tank 3 is covered with a heater 8, for example, a jacket-shaped mantle heater having a resistance heating element. The heater 8 of the raw material tank 3 is configured so that the temperature of the raw material tank 3 can be adjusted by adjusting electric power supplied from a power source (not shown). The set temperature of the heater 8 of the raw material tank 3 is set to a temperature in a range where the solid raw material 300 is sublimated and WCl ₆ is not decomposed, for example, 150 ° C.

  Subsequently, the film forming units 1A to 1C and the raw material supply systems 2A to 2C will be described by taking the raw material supply system 2A connected to the film forming unit 1A and the film forming unit 1A as an example. As shown in FIG. 2, the film forming unit 1 </ b> A holds the wafer 100 horizontally in a vacuum container 10 that is a processing container, and supplies a mounting table 12 having a heater (not shown), source gas, and the like to the vacuum container 10. And a gas introduction part 11 (specifically, a gas shower head) to be introduced into the interior. The vacuum vessel 10 is made of, for example, aluminum, and the inner surface is coated with, for example, alumite. The vacuum vessel 10 is provided with a pressure gauge 110 for measuring the internal pressure.

  Further, the vacuum vessel 10 is provided with a loading / unloading port 19 for loading / unloading the wafer 100. The loading / unloading port 19 is connected to a vacuum transfer chamber (not shown) via a gate valve 20. A load lock chamber or the like is connected to the vacuum transfer chamber, and the wafer 100 is transferred by a transfer arm provided in the vacuum transfer chamber under a high vacuum of, for example, 1 torr (133 Pa) or less. Further, a heater (not shown) is embedded in the inner wall of the vacuum vessel 10, and for example, the vacuum vessel 10 is heated to 160 ° C. to suppress the deposition of the raw material.

A gas supply pipe 15 is connected to the gas introduction section 11. A raw material supply pipe 37 serving as a supply flow path for supplying a raw material gas containing WCl ₆ from the raw material supply system 2 A is connected to the gas supply pipe 15. A reaction gas supply pipe 70 for supplying a reaction gas that reacts with the gas is joined. Further, when the vacuum vessel 10 side is downstream, a replacement gas supply pipe 75 for supplying a replacement gas is joined upstream of the joining point of the raw material supply pipe 37 and the reaction gas supply pipe 70. The other end side of the reaction gas supply pipe 70 is connected to a gas supply pipe 73 connected to a reaction gas supply source 71 which is a supply source of H ₂ gas, and a supply source 72 of an inert gas such as nitrogen (N ₂ ) gas. It branches off to a connected gas supply pipe 74. The other end side of the replacement gas supply pipe 75 is connected to a supply source 76 of a replacement gas, for example, N ₂ gas. A mass flow meter 77 is provided in the raw material supply pipe 37. V73 to V75 in the figure are valves provided in the gas supply pipe 73, the gas supply pipe 74, and the replacement gas supply pipe 75, respectively.

  The raw material supply system 2A sublimates in the raw material tank 3, re-solidifies and captures the raw material supplied together with the carrier gas, and two raw material capturing units 41 and 42 that serve as raw material supply sources for the film forming unit 1A. It has. As shown in FIGS. 3 and 4, the raw material catching portions 41 and 42 are each formed of a lower case 51 formed of, for example, stainless steel in a schematic box shape having a height of 130 mm, a width of 130 mm, and a length of 175 mm opened on the upper surface side. A rectangular tube-like case body 40 is provided, which is composed of a stainless steel lid portion 52 that is welded to the upper surface of the case 51 and closes the opening of the lower case 51. In the following description, one end side in the length direction of the case body 40 will be described as a front surface 40A and the other end side as a rear surface 40B.

  A plate-shaped capturing portion 43 whose surface is a solidified surface is formed on the inner peripheral surface of the case body 40. The capturing part 43 includes a capturing part 43 extending from the right wall part toward the left wall part as viewed from the front side, and a capturing part 43 extending from the left wall part toward the right wall part. , Are arranged alternately in the length direction of the lower case 51. Accordingly, a bent flow path having a labyrinth structure is formed in the case body 40.

In the position above the center in the height direction of the case body 40, the right side wall portion extends rearward from the position on the right side of the front surface 40 </ b> A of the case body 40, and the rear side (back side) wall portion and left side wall A refrigerant flow path 53 is formed through the wall so as to be routed to the left side of the front surface 40A of the case body 40. In FIG. 3, 54 is an inlet of the refrigerant channel 53, 55 is an outlet of the refrigerant channel 53, the supply pipe 44 to which the refrigerant is supplied from the chiller 46 is connected to the inlet 54, and the outlet 55 is connected to the refrigerant Is connected to the chiller 46. In this way, the refrigerant flow path 53 goes around the inside of the case body 40, and for example, cooling water that is a refrigerant flows therethrough. WCl ₂ O ₂ (tungsten dichloride dioxide) and WCl ₄ O (tungsten tetrachloride oxide) which are below the freezing point of WCl ₆ which is the main component of the raw material gas by the flow of cooling water and are contained in WCl ₆ The one and the other raw material traps 41 and 42 are forcibly cooled to a temperature at which the material does not solidify. The refrigerant flow path 53, the supply pipe 44, the discharge pipe 45, and the chiller 46 constitute a cooling unit.

  In addition, a heating unit 49 made of, for example, a resistance heating body that extends in the front-rear direction of the case body 40 is embedded above the left wall portion and below the right wall portion of the case body 40. The cooling unit and the heating unit 49 constitute a temperature adjusting unit, and in the embodiment of the present invention, the temperature adjusting unit changes the output of the heating unit 49 while flowing the cooling water, thereby changing one of the other and the other. The temperature of the raw material capturing parts 41 and 42 is adjusted between the temperature for capturing the raw material and the temperature for sublimating the raw material.

  Returning to FIG. 2, one branch pipe 31 of the branch pipes 31 and 33 branched from the pipe 30 for material replenishment to one end side (upstream side) in the length direction is provided in the case body 40 in one raw material capturing portion 41. The downstream end of the other branch pipe 33 is connected to one end side (upstream side) in the length direction of the case body 40 in the other raw material trap 42. The material replenishment pipe 30 and the branch pipes 31 and 33 correspond to a replenishment flow path. In the figure, V0 is a valve.

  Further, the case body 40 in one raw material capturing portion 41 has an upstream end of one branch pipe 32 of the branch pipes 32 and 34 branched from the raw material supply pipe 37 on the other end side (downstream side) in the length direction. The upstream end of the other branch pipe 34 is connected to the other end side (downstream side) in the length direction of the case body 40 in the other raw material capturing portion 42. Therefore, one raw material capturing part 41 and the other raw material capturing part 42 are connected in parallel to the flow path between the raw material tank 3 and the film forming process part 1A. Valves V1 and V3 are provided in the upstream and downstream branch pipes 31 and 33 of the one and other raw material capturing parts 41 and 42, respectively, and the downstream branch pipes 32 and 32 of the one and other raw material capturing parts 41 and 42 are provided. 34 are provided with valves V2 and V4, respectively. The raw material supply pipe 37 and the branch pipes 32 and 34 correspond to supply flow paths.

Further, in order to supply the raw material supply system 2A with the raw material gas from the one and the other raw material traps 41 and 42 to the film forming unit 1A, an inert gas such as N ₂ gas is supplied to the one and the other raw material traps 41 and 42. A carrier gas supply pipe 60 for supplying the carrier gas is provided. The carrier gas supply pipe 60 is branched into pipes 61 and 62. The pipe 61 is connected to the downstream side of the valve V 1 in the branch pipe 31, and the pipe 62 is connected to the downstream side of the valve V 3 in the branch pipe 33. ing. The carrier gas supply pipe 60 is provided with a mass flow controller 63 for adjusting the flow rate of the carrier gas.

Next, an exhaust path for supplying an exhaust gas containing a source gas exhausted from the vacuum vessel 10 to one and the other source traps 41 and 42 will be described. The vacuum vessel 10 is provided with a main exhaust passage 13 and is evacuated by a vacuum evacuation mechanism 24 including, for example, a vacuum pump. The main exhaust path 13 is provided with a valve V13 and a pressure adjusting unit 16 for adjusting the pressure in the vacuum container 10 from the vacuum container 10 side.
Further, one end of a return pipe line 80 made of, for example, stainless steel is connected to the vacuum vessel 10 side of the main exhaust path 13 from the valve V13. The other end side of the return pipe 80 is branched into return pipes 81 and 82, the return pipe 81 is connected to the downstream side of the valve V <b> 1 in the branch pipe 31, and the return pipe 82 is a valve in the branch pipe 33. It is connected to the downstream side of V3. Valves V9 and V10 are interposed in the return pipes 81 and 82, respectively.

  Furthermore, the raw material supply system 2A is provided with a merging pipe 38 for exhausting the gas that has passed through the one and the other raw material traps 41 and 42 when the one and the other raw material traps 41 and 42 are cooled. One end side of the junction pipe 38 is connected to a position on the vacuum exhaust mechanism 24 side of the main exhaust path 13 with respect to the pressure adjusting unit 16. The other end of the junction pipe 38 is branched into exhaust pipes 35 and 36, the exhaust pipe 35 is connected to the upstream side of the valve V <b> 2 in the branch pipe 32, and the exhaust pipe 36 is upstream of the valve V <b> 4 in the branch pipe 34. It is connected to the. Valves V5 and V6 are interposed in the exhaust pipes 35 and 36 and the junction pipe 38, respectively. The exhaust pipes 35 and 36 are provided with pressure adjusting parts 17 and 18 for adjusting the pressure in the one and the other raw material capturing parts 41 and 42, respectively. Further, the pressure adjusting unit 17 adjusts the pressure in the vacuum container 10 when passing through the one raw material capturing unit 41 from the vacuum vessel 10 and exhausting, and the pressure adjusting unit 18 sends the other raw material from the vacuum vessel 10. The pressure in the vacuum vessel 10 is adjusted when the trap 42 is exhausted through the exhaust.

  In the first embodiment, the vacuum vessel 10 passes through one of the raw material capturing portions 41 via the return pipe 80 and the return pipe 81, and the exhaust pipe 35, the merge pipe 38, and the main exhaust path 13 are passed through. The exhaust path exhausted through the first exhaust line corresponds to the first exhaust path when viewed from one raw material capturing unit 41. One exhaust path passes from the vacuum vessel 10 via the return pipe 80 and the return pipe 82 to the other raw material trap 42 and is exhausted via the exhaust pipe 36, the junction pipe 38, and the main exhaust path 13. This corresponds to the second exhaust passage when viewed from the raw material capturing portion 41.

An exhaust path that passes from the vacuum vessel 10 through the other raw material trap 42 through the return pipe 80 and the return pipe 82 and is exhausted through the exhaust pipe 36, the merge pipe 38, and the main exhaust path 13 is provided. This corresponds to the first exhaust path when viewed from the other raw material trap 42. Further, the exhaust path that passes through the one raw material trap 41 through the return pipe 80 and the return pipe 81 from the vacuum vessel 10 and is exhausted through the exhaust pipe 35, the merge pipe 38, and the main exhaust path 13 is the other. This corresponds to the second exhaust passage when viewed from the raw material capturing portion 42.
Therefore, the valves V5, V6, V9, V10, and V13 for switching the exhaust path for performing vacuum exhaustion between the first exhaust path and the second exhaust path correspond to a switching unit.

  Also, a material replenishment pipe 30, branch pipes 31 and 33, a raw material supply pipe 37, branch pipes 32 and 34, exhaust pipes 35 and 36, a merge pipe 38, a return pipe 80, through which a gas containing a raw material gas passes, 81 and 82 and the main exhaust passage 13 are covered with, for example, a tape heater (not shown), and the region covered with the tape heater is heated to a temperature at which the source gas does not precipitate, for example, 160 ° C.

  Each device of the raw material supply systems 2 </ b> A to 2 </ b> C and the raw material tank 3 are configured to be controlled by the control unit 9. The control unit 9 controls on / off of each of the heating unit 49 of one raw material capturing unit 41, the heating unit 49 of the other raw material capturing unit 42, and the heater 8 of the raw material tank 3, and controls each of the valves V0 to V10, V13. A program in which a group of steps (commands) for executing open / close control, flow rate control by the mass flow controllers 63 and 65, pressure control by the pressure adjusting units 16 to 18, and the like is provided. The program is stored in a computer storage medium such as a flexible disk, a compact disk, a hard disk, a magneto-optical disk, etc., and is installed in the control unit 9.

  Next, the operation of the above-described embodiment will be described with reference to FIGS. 5 to 7 by taking the raw material supply system 2A as an example. 5 to 11, the open valve is shown in white, and the closed valve is hatched. The operation of the apparatus for performing the film forming process is started, and the solid raw material 300 in the raw material tank 3 has not been consumed yet, and the solid raw material 300 is contained in one and the other raw material traps 41 and 42. The explanation will be made assuming that it has not been captured yet. First, the heater 8 of the raw material tank 3 is turned on, the raw material tank 3 is heated to, for example, 150 ° C., the solid raw material 300 is vaporized (sublimated), and the concentration of the raw material in the raw material tank 3 is increased to a concentration close to the saturation concentration. . Moreover, the heating part 49 is turned on, and one raw material capture | acquisition part 41 is heated to 60 degreeC, for example.

  Next, as shown in FIG. 5, the valve V64 of the carrier gas supply path 64 connected to the raw material tank 3, the valves V0 and V1 of the pipe 30 connecting the raw material tank 3 and the one raw material capturing part 41, and one raw material capturing. The valve V5 of the exhaust pipe 35 on the part 41 side is opened. As a result, the carrier gas is supplied to the raw material tank 3, sublimated in the raw material tank 3, and the saturated raw material together with the carrier gas through the raw material replenishment pipe 30 and the branch pipe 31, one raw material capturing section 41. The case body 40 is supplied. The gas that has passed through the case body 40 is discharged from the branch pipe 32 and exhausted from the main exhaust path 13 through the exhaust pipe 35.

The temperature in the case body 40 of one raw material capturing part 41 is set to 60 ° C., which is lower than the freezing point of WCl _{6 as} the raw material. For this reason, the curved path, which is a maze formed by the multistage capturing section 43, is captured and deposited (re-solidified) on the inner surface of the capturing section 43 and the case body 40 when the raw material that is gas passes through, and the capturing section. WCl ₆ adheres to the surface of 43 in the form of a thin film. The raw material traps 41 and 42 are case bodies 40 so that almost all of the raw material in the raw material gas is trapped (re-solidified) when the raw material gas containing the carrier gas and the raw material is passed through the raw material traps 41 and 42. , The distance between the capturing portions 43, the number of steps, and the like are set.

Here, the solid material commercially available WCl _6, contains _WCl 2 _{O 2} or WCl ₄ O traces with normal WCl _6. Since WCl ₆ has a freezing point higher than 60 ° C., it resolidifies when cooled to 60 ° C. However, since WCl ₂ O ₂ and WCl ₄ O have a freezing point lower than 60 ° C., they do not solidify at 60 ° C. Therefore, when the temperature of one raw material capturing part 41 is set to 0 ° C. to 60 ° C., for example, 60 ° C., and the raw material gas is re-solidified by passing through one raw material capturing part 41, WCl ₆ The WCl ₂ O ₂ and WCl ₄ O deposit on the trap 41 and pass through one raw material trap 41 to be exhausted together with the carrier gas.

  The valve V1 is closed when the amount of raw material deposited on one raw material capturing portion 41 becomes 400 g, for example. The point in time when the set amount of raw material is deposited in one raw material capturing unit 41 is managed, for example, by the flow time of the gas into one raw material capturing unit 41. Thus, one raw material capturing unit 41 is ready as a raw material supply source for the film forming processing unit 1A.

  Next, before starting the film formation, the heating unit 49 of the one raw material capturing unit 41 is turned on, and the inside of the case body 40 is raised to a set temperature of 150 to 200 ° C., for example, 160 ° C., as described above. The raw material deposited on one raw material trap 41 is sublimated. Then, the valve V7 of the carrier gas pipe 61 is opened, the carrier gas is supplied to one of the raw material capturing portions 41, and the raw material gas that is a mixed gas of the sublimated raw material and the carrier gas is formed from the one raw material capturing portion 41. The membrane processing unit 1A is bypassed and exhausted by the vacuum exhaust mechanism 24 through the exhaust pipe 35 and the junction pipe 38, and the flow rate of the source gas is stabilized. Further, the valves V9 and V10 of the return pipes 81 and 82 branched from the main exhaust passage 13 are closed, and the valve V13 of the main exhaust passage 13 is opened, and the vacuum vessel 10 is evacuated, and the inside of the vacuum vessel 10 Is set to 1 Torr (133 Pa) or less, for example. Thereafter, the gate valve 20 is opened, and the wafer 100 is loaded into the vacuum vessel 10 by the transfer arm (not shown) in the vacuum transfer chamber and mounted on the mounting table 12.

After that, the gate valve 20 is closed, for example, the valve V75 shown in FIG. 2 is opened to supply N ₂ gas into the vacuum vessel 10, and a pressure similar to the pressure during the film forming process, for example, 10 to 50 Torr (1.33 KPa). The pressure is increased to about 6.67 KPa). On the other hand, the wafer 100 is heated to, for example, 500 ° C. by a heater (not shown) provided on the mounting table 12.

Subsequently, after the pressure rises to 10 Torr (1.33 KPa) or more and the wafer 100 is sufficiently heated, the valve V2 provided in the branch pipe 32 and the valve V7 of the carrier gas pipe 61 as shown in FIG. And close the valve V75 shown in FIG. 2 (see FIG. 2). As a result, the carrier gas is supplied to one raw material capturing unit 41, and the raw material gas containing the carrier gas and the raw material is supplied from one raw material capturing unit 41 to the vacuum vessel 10, and WCl ₆ is adsorbed on the surface of the wafer 100.

  The other raw material trap 42 is set to 60 ° C., the valve V13 of the main exhaust passage 13 is closed, the valve V6 of the exhaust pipe 36 on the other raw material trap 42 side, and the return pipe on the other raw material trap 42 side. V10 of the road 82 is kept open. As a result, the exhaust gas exhausted from the vacuum vessel 10 passes through the other raw material trap 42 via the main exhaust path 13 and the return pipes 80 and 82, and passes through the branch pipe 36, the junction pipe 38, and the main exhaust path 13. Exhausted through.

At this time, the WCl ₆ that is the raw material contained in the exhaust gas is cooled to the freezing point, and thus precipitates on the other raw material capturing portion 42. Subsequently, the valve V2 is closed and the valve V75 shown in FIG. 2 is opened. As a result, N ₂ gas as a replacement gas is supplied into the vacuum vessel 10. Even when the replacement gas and the subsequent H 2 gas are supplied to the vacuum vessel 10, the exhaust path is the same as the state shown in FIG. That is, since the exhaust gas containing the raw material remaining in the vacuum vessel 10 at the time of supplying the replacement gas passes through the other raw material capturing portion 42 and is exhausted, the raw material contained in the exhaust gas is captured.

Subsequently, the valve V75 shown in FIG. 2 is closed, and the valves V73 and V74 are opened. As a result, H ₂ gas, which is a reactive gas, is supplied to the vacuum vessel 10. As a result, WCl ₆ adsorbed on the wafer 100 is reduced by H ₂ to form a monoatomic W film.
At this time, by-products such as WCl ₄ , WCl ₅ , H ₂ , HCl, and Cl ₂ are generated by H ₂ and the remaining WCl _6, and pass through the other raw material trap 42 as exhaust gas. Compared with the raw material WCl ₆ , the decomposition products WCl ₄ , WCl ₅ , H ₂ , HCl, Cl ₂ have a higher vapor pressure. The other raw material capturing part 42 is 10 to 50 Torr (1.33 KPa to 6.67 KPa) which is approximately the same pressure as the vacuum vessel 10, and is set to 0 ° C. to 60 ° C., for example, 60 ° C. Therefore, only WCl ₆ is deposited on the other raw material capturing part 42, and decomposition products such as WCl ₄ , WCl ₅ , H ₂ , HCl, Cl ₂ pass through the other raw material capturing part 42 and are exhausted. Is done. Then, after the valves V73 and V74 shown in FIG. 2 are closed, the valve V75 is opened and the replacement gas is supplied to the vacuum vessel 10 to replace the atmosphere in the vacuum vessel 10. In this way, by repeating on / off control of the valves V2, V73, V74, and V75, the cycle of supplying the raw material gas containing WCl ₆ → the replacement gas → the reaction gas → the replacement gas into the vacuum vessel 10 is repeated a plurality of times. The W film is formed.

Supplying one wafer 100 per 30g about WCl6 the vacuum vessel 10, deposited, for example WCl ₆ of about 1.5g contributes. Further, for example, about 1.0 g of WCl ₆ is decomposed, and about 1.5 g of WCl ₆ is attached to the vacuum vessel 10. The remaining 26 g and 1 g of decomposition products, for example, WCl ₄ , WCl ₅ , H ₂ , HCl, Cl _2, etc. pass through the other raw material trap 42 and are exhausted. Therefore, approximately 94% of the raw material is recovered by the other raw material capturing unit 42.

  Further, when the raw material gas and the reaction gas are supplied to the vacuum vessel 10, the temperature of the vacuum vessel 10 is about 160 ° C., and the pressure in the vacuum vessel 10 is 10 to 50 Torr (1.33 KPa to 6.3). 67 KPa). Therefore, there is little corrosion of the metal in the vacuum vessel 10, and almost no metal is contained in the exhaust of the vacuum vessel 10. Moreover, in the above-mentioned embodiment, since the inner surface of the vacuum vessel 10 is covered with alumite, metal corrosion can be further suppressed.

The return lines 80 to 82 are made of stainless steel, and the temperature during the process is set to 160 ° C. For this reason, there is little possibility that metal is mixed while exhaust gas flows from the vacuum vessel 10 to the other raw material trap 42. Therefore, the main raw material WCl ₆ is precipitated with high purity in the other raw material trap 42.

  After the film forming process by the ALD method is completed, as shown in FIG. 7, the valve V10 of the return pipe 82 connected to the other raw material trap 42 is closed and the valve V13 of the main exhaust path 13 is opened. As a result, the exhaust from the vacuum vessel 10 is exhausted without passing through the other raw material trap 42. Thereafter, the pressure adjusting unit 16 lowers the pressure in the vacuum vessel 10 to 1 Torr (133 Pa) or less, and then the gate valve 20 is opened to take out the wafer 100. As will be described later, since the process of replenishing the raw material from the raw material tank 3 to the other raw material capturing part 42 is performed, the valve V3 of the pipe 33 is opened while this valve V10 is closed, and a part of the process is performed. May be performed.

  When the wafer 100 is taken in and out, the pressure in the vacuum vessel 10 is set to a high vacuum of 1 Torr (133 Pa) or less. When a high vacuum of 1 Torr (133 Pa) or less is used, a metal material that does not sublime may be sublimated from the vacuum vessel 10 during the film forming process. Therefore, when loading / unloading the wafer 100 into / from the vacuum vessel 10, the valve V10 is closed and V13 is opened before the pressure in the vacuum vessel 10 is reduced to, for example, 10 Torr (1330 Pa) or less, and then the other pressure is reduced. The possibility that metal is mixed into the raw material trap 42 is reduced.

Thereafter, for example, after the processing of one lot of wafers W is completed, the amount of the raw material captured by the other raw material capturing unit 42 is measured. For example, a known build-up method may be used for measuring the amount of the raw material.
Here, the build-up method will be described. When the raw material is deposited in the sealed container, the volume of the vapor phase of the container is reduced. The pressure when gas is supplied at a constant flow rate in a vacuum container at a constant temperature follows the Boyle's law and is inversely proportional to the volume. In a state where the raw material is not deposited in the order container, obtaining the supply amount and the volume of the container by the change in pressure of the N ₂ gas at the time of supplying the N ₂ gas into the container. And by precipitating the raw material into the container, by subtracting the volume of supply amount and the container the gas phase which is obtained by a change in pressure of the N ₂ gas at the time of supplying the N ₂ gas into the container, it precipitated ingredients are The volume is determined. Further, since the volume of the raw material is obtained, the weight of the deposited raw material can be known by grasping the density of the raw material in advance. Thereafter, the valve V3 is opened, and the shortage of raw material is replenished from the raw material tank 3 to the other raw material capturing unit 42.

  When the wafer 100 of the subsequent lot is loaded into the vacuum container 10 after or while the other material capturing unit 42 is replenished with the material, it is the same as when the wafer 100 is loaded or unloaded. The wafer 100 is loaded into the vacuum container 10 while the valve V13 is opened and the vacuum container 10 is evacuated through the main exhaust passage 13. Then, after the replenishment of the raw material is completed in the other raw material capturing unit 42 and preparation for using the other raw material capturing unit as a raw material supply source is completed, the other raw material capturing unit 42 is heated to 160 ° C. The raw material captured by the part 42 is sublimated. Thereafter, the valve V8 of the pipe 61 connected to the other raw material capturing part 42 is opened to supply the carrier gas to the other raw material capturing part 42 and at the same time as when the one raw material capturing part 41 is used as the raw material supply source. After the valve V6 is opened to stabilize the flow rate of the raw material gas, the valve V4 of the branch pipe 34 connected to the other raw material trap 42 is opened and the valve V6 is closed. As a result, the raw material is supplied from the other raw material trap 42 to the vacuum vessel 10. In addition, after setting the temperature of one raw material trap 41 to 60 ° C., the valve V13 is closed and the valve V5 of the exhaust pipe 35 and the valve V9 of the return pipe 81 are opened. As a result, the exhaust gas containing the raw material exhausted from the vacuum container 10 is exhausted through the one raw material capturing unit 41, and the raw material contained in the exhaust gas is captured by the one raw material capturing unit 41.

  In this way, while using one of the raw material capturing units 41 as a raw material supply source for the film forming processing unit 1A, the other raw material capturing unit 42 captures the raw material by passing the exhaust gas through the other raw material capturing unit 42, and the other raw material While using the trap 42 as a raw material supply source, the process of trapping the raw material by passing the exhaust gas through one of the raw material traps 41 is alternately repeated. That is, one raw material capturing unit 41 and the other raw material capturing unit 42 are alternately used as a raw material supply source. In the other source supply systems 2B and 2C shown in FIG. 1, the source gas is supplied to the film forming units 1B and 1C in the same manner.

According to the above-described embodiment, when the WCl ₆ is sublimated and supplied to the vacuum container 10 together with the carrier gas to perform the film forming process, the raw material in the exhaust gas exhausted from the vacuum container 10 is captured as one raw material. The part 41 or the other raw material capturing part 42 captures (resolidifies), sublimates the captured raw material, and reuses it as a processing gas. Therefore, the consumption of raw materials can be reduced.
As described above, the present invention is extremely effective from the circumstances that the thinning of the thin film has progressed in the semiconductor device, the surface area of the wafer 100 is increased, and the amount of the raw material used is increased.
Further, when one of the one and the other raw material traps 41 and 42 is used as a raw material supply source, the exhaust gas from the vacuum vessel 10 is passed to the other to capture and collect the raw material in the exhaust gas. As a result, a decrease in the operating rate of the apparatus can be suppressed.

  In the present invention, in addition to the two raw material capturing units 41 and 42, a raw material capturing unit 101 configured similarly to the raw material capturing units 41 and 42 may be provided. In such an example, for example, as shown in FIGS. 9 to 11, three raw material traps 41, 42, and 101 are connected in parallel to each other. 9 to 11, reference numeral 102 denotes a branch pipe branched from the pipe 30; 103, a branch pipe branched from the raw material supply pipe 37; 104, an exhaust pipe branched from the other end side of the merge pipe 38; Is a branch path branched at the other end side of the return pipe 80. In addition, a carrier gas supply pipe (not shown) is connected to the raw material trap 101 in the same manner as the raw material traps 41 and 42. V102 to V105 are valves. In the specification, FIGS. 9 to 11 are shown as a raw material capturing part 41 on the left side, a raw material capturing part 42 on the center, and a raw material capturing part 101 on the right side when viewed from the front.

  In the second embodiment, as shown in FIG. 9, first, the raw material is replenished from the raw material tank 3 to the left raw material capturing unit 41 and the central raw material capturing unit 42. Thereafter, when supplying the raw material to the film forming unit 1A, first, as shown in FIG. 10, the valves V2 and V7 are opened, and the raw material is supplied from the left-side raw material capturing unit 41 to the vacuum vessel 10. That is, the left-side raw material capturing unit 41 is used as a raw material supply source. Then, the valves V104 and V105 are opened, and the exhaust gas from the vacuum vessel 10 is caused to flow through the right-side material capturing unit 101 so that the material is deposited on the right-side material capturing unit 101.

  After supplying the raw material using the left raw material capturing part 41 as a raw material supply source in this way, the raw material is supplied from the central raw material capturing part 42 to the vacuum vessel 10 as shown in FIG. The exhaust gas from is allowed to flow through the left raw material capturing part 41 to deposit the raw material. During this time, the raw material catching unit 101 on the right side is replenished with a shortage of raw material from the raw material tank 3. Thereafter, the raw material is supplied from the right raw material capturing unit 101 to the vacuum container 10, and the exhaust from the vacuum container 10 is exhausted by passing through the central raw material capturing unit 42, and the left raw material capturing unit 41 is insufficient. Capture raw materials. With this configuration, when the processing of one lot of wafers is completed, the raw material capturing unit for forming a film on the wafer 101 of the subsequent lot is in a standby state (a state in which it can be used as a raw material supply source). Therefore, there is no waiting time for replenishing the raw material in the raw material capturing part. Therefore, the film forming apparatus can be operated continuously, which is effective in terms of operating efficiency.

There may be only one raw material trap. For example, in the raw material supply system 2 </ b> A shown in FIG. 2, there is an example in which the branch pipe 31 and the pipe 37 are connected without providing one raw material capturing unit 41. In this case, the raw material is supplied from the raw material tank 3 together with the carrier gas through the branch pipe 31 and the pipe 37 to the film forming processing unit 1A to perform the film forming process, and the exhaust gas from the vacuum vessel 10 is supplied to the other side. The material is passed through the material capturing unit 42 to capture the material in the exhaust gas. Thereafter, the raw material supply source may be switched from the raw material tank 3 to the other raw material capturing unit 42 to perform the film forming process.
In such an example, the vacuum vessel 10 passes through the raw material trap 42 through the return pipe 80 and the return pipe 82, and is exhausted through the exhaust pipe 36, the junction pipe 38, and the main exhaust path 13. The exhaust path corresponding to the first exhaust path corresponds to the first exhaust path, and the exhaust path exhausted from the main exhaust path 13 by the vacuum exhaust mechanism 24 corresponds to the second exhaust path.

  Furthermore, the present invention can suppress the consumption of the raw material even when applied to the CVD method in which the raw material gas and the reaction gas are supplied to the vacuum vessel 10 to perform the film formation process. Since the film formation process is performed by replacing the gas and the reaction gas with a replacement gas, the contribution ratio of the raw material supplied to the vacuum vessel 10 to the film formation is low and a large amount is exhausted. Therefore, it can be said that the present invention is more effective when applied to the ALD method.

Moreover, the solid raw material should just be a raw material whose vapor pressure of a main raw material is lower than the vapor pressure of the main by-product. For example, WCl ₅ (tungsten pentachloride), MoCl ₅ (molybdenum pentachloride), ZrCl ₄ (zirconium chloride (IV)), HfCl ₄ (hafnium (IV) chloride), AlCl ₃ (aluminum chloride), and the like may be used.

1A to 1C Film formation processing units 2A to 2C Raw material supply system 3 Raw material tank 8 Heater 9 Control unit 13 Main exhaust passage 41 One raw material capture portion 42 Other raw material capture portion 43 Capture portions 80, 81, 82 Return pipes V1 V10 valve

Claims (8)

A film forming process performed on a target object by sublimating a solid source of a source supply source and supplying it into a processing container in a vacuum atmosphere together with a carrier gas, wherein the vapor pressure of the by-product is In a film forming apparatus for performing a film forming process higher than the vapor pressure,
A first exhaust path for evacuating the inside of the processing container by an evacuation mechanism;
A raw material capturing portion provided in the first exhaust path for capturing the raw material in the gas;
Provided by bypassing the raw material trapping section, a carrier gas is supplied to the second exhaust path for evacuating the inside of the processing vessel by a vacuum exhaust mechanism and the raw material trapping section, and trapped by the raw material trapping section. A carrier gas supply unit for sublimating the raw material and supplying the raw material into the processing container via the raw material supply path;
A temperature adjusting unit for adjusting the temperature of the raw material capturing unit between a temperature for capturing the raw material and a temperature for sublimating the captured raw material;
When a film forming process is performed on the object to be processed using a raw material supply source other than the raw material capturing unit, vacuum exhaust is performed by the first exhaust path, and when the raw material capturing unit is used as a raw material supply source, the first exhaust channel is used. A film forming apparatus comprising: a switching unit that switches an exhaust path so that vacuum exhaust is performed by two exhaust paths.   When the object to be processed is carried into or out of the processing container, the pressure in the processing container is set lower than the pressure during the film forming process, and vacuum exhaust is performed by the second exhaust path, 2. The film forming apparatus according to claim 1, wherein the exhaust path is switched so that the exhaust gas does not pass through the raw material capturing section. A plurality of the raw material capturing parts are provided,
A first exhaust path is provided corresponding to each of the plurality of raw material capturing units,
When one raw material capturing part of the plurality of raw material capturing parts is used as a raw material supply source, the first exhaust path provided with the other raw material capturing part is the second viewed from the one raw material capturing part. The film forming apparatus according to claim 1, wherein the film forming apparatus corresponds to an exhaust path.   The film forming apparatus according to any one of claims 1 to 3, wherein three or more of the raw material capturing units are provided and are sequentially used as a raw material supply source.   5. The film forming process according to claim 1, wherein the film forming process is a process performed by reacting a raw material obtained by sublimating the solid raw material with hydrogen gas. 6. apparatus. Sublimating a solid raw material of a raw material supply source and supplying it into a processing container in a vacuum atmosphere together with a carrier gas to perform a film forming process on the object to be processed;
While performing the step, the inside of the processing vessel is evacuated through the first exhaust passage, and the raw material capture provided at the first exhaust passage and set to a temperature for capturing the raw material Capturing the raw material in the exhaust gas in the part,
Thereafter, a step of setting the temperature of the raw material capturing unit to a temperature for sublimating the raw material,
A carrier gas is supplied to the raw material capturing unit set to a temperature for sublimating the raw material, and the raw material captured by the raw material capturing unit is sublimated and supplied into the processing container through the raw material supply path. Performing a film forming process on the processing body, and evacuating the inside of the processing container via a second exhaust path that bypasses the raw material capturing unit,
A film forming method, wherein a vapor pressure of a by-product during the film forming process is higher than a vapor pressure of the raw material.   When the object to be processed is carried into or out of the processing container, the pressure in the processing container is set lower than the pressure during the film forming process, and vacuum exhaust is performed by the second exhaust path, The film forming method according to claim 6, wherein the exhaust path is switched so that the exhaust gas does not pass through the raw material capturing section. A storage medium storing a computer program used in a film forming apparatus for sublimating a solid material of a raw material supply source and supplying it into a processing container in a vacuum atmosphere together with a carrier gas to perform a film forming process on an object to be processed There,
A storage medium, wherein the computer program includes a group of steps so as to execute the film forming method according to claim 6 or 7.

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