JP2006245256A - Forming method of thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of a thin film wherein the purge efficiency in the thin film forming process according to ALD method is increased to be able to prevent the remaining of a raw material gas and an oxidizing gas and to reduce the purge time. <P>SOLUTION: In this forming method of the thin film, the raw material gas containing metal atoms and silicon atoms is supplied into a treatment atmosphere, and the raw material gas component is adsorbed by the treatment surface of a substrate, and the process (S101) for forming a layer containing the metal atoms and the silicon atoms is carried out. Then, an inert gas is supplied into the treatment atmosphere, and the process (S102) for purging the raw material gas is carried out. Then, the oxidizing gas is supplied into the treatment atmosphere and reacts with the raw material gas component, and the process (S103) for forming a layer containing oxygen atoms is carried out. Thereafter, an inert gas is supplied into the treatment atmosphere, the process (S104) for purging the oxidizing gas is carried out, and S101 to S104 are repeated to form the thin film. Further, in this forming method of the thin film, the process for temporarily pressurizing the treatment atmosphere is inserted into S104. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming a thin film, and more particularly to a method for forming a thin film by which an insulating film made of a high-k material is formed by an atomic layer deposition (ALD) method.

With the miniaturization of devices, development of a High-k material as a material for a gate insulating film and a capacitor insulating film is underway. Since an insulating film made of a High-k material has a high relative dielectric constant, for example, when used as a gate insulating film, even if the film thickness is several times thicker than when silicon oxide (SiO ₂ ) is used, There is an advantage that the same gate capacitance as that when SiO ₂ is used can be obtained.

  As such a high-k material film formation method, an example using the ALD method has been reported (for example, see Patent Document 1). By depositing a High-k material using the ALD method, it is possible to highly control the thickness and composition of the insulating film.

  Here, an example of forming, for example, a metal silicate film, which is a high-k material, using a single-wafer apparatus by the ALD method will be described. In this case, a layer of metal atoms and silicon atoms is formed by supplying a source gas containing metal atoms and a source gas containing silicon atoms into the processing chamber and adsorbing the source gas components on the processing surface of the substrate. To do. Next, an inert gas is supplied into the processing chamber, and unreacted source gas is purged. Thereafter, an oxidizing gas is supplied into the processing chamber to react with the source gas component adsorbed on the processing surface to form a layer of oxygen atoms bonded to metal atoms or silicon atoms. Subsequently, an unreacted oxidizing gas is purged by supplying an inert gas into the processing chamber. Then, a metal silicate film is formed by sequentially repeating these steps.

  Since the ALD method as described above is a low temperature process, unreacted source gas and oxidizing gas are likely to remain. This prevents impurities from remaining in the film due to the remaining source gas, generates particles due to the reaction between the source gas and the oxidizing gas in the gas phase, and the residual gas of the source gas or oxidizing gas. In order to prevent consumption due to this reaction, the purge step is performed for 5 to 10 seconds.

JP 2003-318174 A

  For this reason, in the method of forming a thin film by the ALD method, the purge time is a major obstacle to improving the throughput.

  In particular, when the surface to be processed has irregularities, such as the formation of a capacitor insulating film in a trench capacitor, even if purging with an inert gas is performed for 5 to 10 seconds, unreacted that has entered the recesses. Removal of source gas and oxidizing gas is not certain. For this reason, there is a problem in that a leak current is generated through trap levels due to impurities in the film due to the remaining source gas. In addition, there is a problem that particles are generated due to a reaction in the gas phase between the remaining source gas and the oxidizing gas, and the film forming apparatus is contaminated. Furthermore, the supplied raw material gas or oxidizing gas is consumed due to the reaction in the gas phase with the remaining raw material gas or oxidizing gas. In particular, the raw material gas or oxidizing gas reaches the bottom surface of the recess. There is also a problem that coverage becomes worse because it becomes difficult to do so.

  An object of the present invention is to increase the purge efficiency of the thin film formation process by the ALD method, thereby preventing the residual of the source gas and the oxidizing gas and reducing the purge time.

  In order to solve the above-described problems, the thin film forming method of the present invention sequentially performs the following steps in the thin film forming method by the ALD method. First, in the first step, a source gas containing at least one of metal atoms and silicon atoms is supplied to the processing atmosphere, and a source gas component is adsorbed on the processing surface of the substrate, thereby including at least one of metal atoms and silicon atoms. Form a layer. Next, in the second step, an inert gas is supplied to the processing atmosphere to purge the raw material gas in the processing atmosphere. Next, in a third step, an oxidizing gas is supplied to the processing atmosphere, and a step of forming a layer of oxygen atoms by reacting with the source gas component adsorbed on the processing surface of the substrate is performed. In the subsequent fourth step, a process of supplying an inert gas to the processing atmosphere and purging the oxidizing gas in the processing atmosphere is performed, and a thin film is formed on the processing surface by repeatedly performing the first to fourth steps. Form. The pressure in the processing atmosphere is temporarily changed in at least one of the second step and the fourth step.

  According to such a method for forming a thin film, the pressure in the processing atmosphere during the purge process is temporarily changed. For example, the amount of inert gas supplied to the processing surface is temporarily increased to increase the processing atmosphere. When the inner pressure is temporarily increased, the processing surface is strongly blown by the inert gas, and the source gas and the oxidizing gas are easily removed from the processing atmosphere. Therefore, the purge efficiency is increased. Further, when reducing the processing atmosphere, the exhaust of the source gas and the oxidizing gas from the processing atmosphere is promoted, so that the source gas and the oxidizing gas are easily removed. Therefore, the purge efficiency is increased.

  By increasing the purge efficiency, the residual source gas and oxidizing gas are suppressed, so that the impurity concentration in the film caused by the source gas is reduced, and the leakage current through the trap level due to the impurities is suppressed. . In addition, since the reaction between the remaining source gas and oxidizing gas is prevented in the gas phase, generation of particles is prevented and consumption of the supplied source gas and oxidizing gas in the gas phase is also prevented. Is done. Furthermore, the purge time can be shortened by increasing the purge efficiency.

  As described above, according to the method for forming a thin film of the present invention, an increase in leakage current is suppressed, so that the yield of manufactured devices can be improved. Further, since the generation of particles is prevented, contamination of the film forming apparatus can be prevented. Furthermore, since the consumption of the source gas and the oxidizing gas in the gas phase is prevented, the source gas and the oxidizing gas can be sufficiently supplied to the bottom of the concave portion of the processing surface having unevenness, and the coverage property Can be improved. Further, since the purge time can be shortened, the throughput can be improved.

  Hereinafter, an example of an embodiment relating to a method for forming a thin film using the ALD method of the present invention will be described in detail.

(First embodiment)
In the present embodiment, an example in which a capacitor insulating film of a deep trench type trench capacitor is formed by an ALD method in a method for manufacturing a semiconductor device will be described. As the capacitor insulating film, a hafnium silicate (HfSiO _x ) film that is a high-k material is formed. Here, in describing a method for forming a hafnium silicate film by the ALD method, an ALD apparatus used for the film formation will be described with reference to the configuration diagram of FIG.

<ALD equipment>
As shown in this figure, the ALD apparatus 10 is a single-wafer type apparatus, and includes a processing chamber 11 for performing a film forming process on the substrate S to be processed. In the processing chamber 11, for example, a stage 12 for placing and holding the substrate to be processed S is disposed at the bottom, and the stage 12 is provided with a heater (not shown) for heating the substrate to be processed S. Yes. Further, an exhaust pipe 13 for removing excess gas and reaction products is connected to, for example, the lower side of the processing chamber 11. A vacuum pump 14 is connected to the exhaust pipe 13, and a valve 13 a whose opening degree can be adjusted is provided between the vacuum pump 14 and the processing chamber 11. By operating this vacuum pump 14, the inside of the processing chamber 11 is configured to be depressurized.

  A plurality of gas supply pipes provided for each gas are connected to, for example, the upper side of the processing chamber 11, and are configured in the processing chamber 11. Although illustration is omitted here, the processing chamber 11 faces the stage 12 so that the supplied gas is supplied to the entire area of the substrate S to be processed placed and held on the stage 12. In the state, it is assumed that a shower head-shaped diffusion plate is provided.

Here, the plurality of gas supply pipes form a hafnium silicate film, so that tetrakis (methylethylamino) hafnium (Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ ) containing Hf atoms is used. A source gas supply pipe 15 for supplying, a source gas supply pipe 16 for supplying tetrakis (methylethylamino) silicon (Si [N (CH ₃ ) (C ₂ H ₅ )] ₄ ) containing Si atoms, and, for example, from ozone And an oxidizing gas supply pipe 17 for supplying the oxidizing gas. In addition to the above, as described later, an inert gas supply pipe 18 for supplying an inert gas in the purge process is provided.

  As described above, the source gas supply pipe 15 has one end connected to the processing chamber 11 and the other end connected to a cylinder 15a in which source gas containing Hf atoms is stored. Further, between the cylinder 15a and the processing chamber 11, a flow rate controller 15b and an openable / closable valve 15c are provided from the cylinder 15a side.

  The source gas supply pipe 16 has one end connected to the processing chamber 11 and the other end connected to a cylinder 16a in which source gas containing Si atoms is stored. The source gas supply pipe 16 is also configured similarly to the source gas 15, and is provided with a flow rate regulator 16b and a valve 16c that can be opened and closed from the cylinder 16a side.

The oxidizing gas supply pipe 17 has one end connected to the processing chamber 11 and the other end connected to a cylinder 17a in which oxygen (O ₂ ) gas is stored. The oxidizing gas supply pipe 17 is provided with an ozone gas generator 17b, a flow rate controller 17c, and a valve 17d in order from the cylinder 17a side. Oxygen gas supplied from the cylinder 17a to the oxidizing gas supply pipe 17 is introduced into the ozone gas generator 17b, so that part of it becomes O ₃ gas and is supplied into the processing chamber 11 together with O ₂ gas.

  Further, the inert gas supply pipe 18 has one end connected to the processing chamber 11 and the other end connected to a cylinder 18a in which an inert gas such as argon (Ar) is stored. A flow rate regulator 18b and a valve 18c that can be opened and closed are provided between the processing chamber 11 and the cylinder 18a.

  Among these gas supply pipes, the source gas supply pipes 15 and 16 and the oxidizing gas supply pipe 17 supply gas to the surface of the substrate S placed and held on the stage 12 in the processing chamber 11. It is preferable to be connected above the chamber 11. Also, the inert gas supply pipe 18 is preferably connected above the processing chamber 11 in order to remove unreacted source gas and oxidizing gas remaining in the vicinity of the processing surface. As will be described later, since the inert gas supply pipe 18 is in a pressurized state and the inert gas is blown onto the processing surface of the substrate S, it is preferably connected above the processing chamber 11.

  Although not shown here, the cylinders 15a, 16a, 17a, 18a of the gas supply pipes described above are each provided with an openable / closable valve, and the valves or valves 15c, 16c on the processing chamber 11 side are provided. , 17d, and 18c, the on / off of the supply of each gas to the processing chamber 11 can be controlled.

<Method for forming thin film>
Next, a method for forming a hafnium silicate film using the ALD apparatus 10 as described above will be described.

  First, a substrate on which a capacitor insulating film made of a hafnium silicate film is formed will be described. As shown in FIG. 2, a substrate 21 made of, for example, single crystal silicon is provided with a deep trench 23 formed by etching using, for example, a hard mask 22 made of SiN as a mask. A lower electrode (not shown) provided by a solid phase diffusion method is formed on the inner wall below the trench 23.

A natural oxide film (SiO ₂ film) formed on the inner wall surface of the trench 23 by performing a cleaning process on the surface of the substrate 21 in this state using, for example, a 0.1% hydrogen fluoride (HF) solution. Remove. Thereafter, a nitridation process is performed at 800 ° C. to form a silicon nitride layer (not shown) on the inner wall surface of the trench 23. This step is performed for suppressing oxygen diffusion to the substrate 21, and the silicon nitride layer is formed with a film thickness of 1 nm or less. As a result, the inner wall of the trench 23 is terminated with a hydrogen atom (H) of an amino (NH ₂ ) group.

  The substrate 21 in this state is placed and held on the stage 12 in the processing chamber 11 of the ALD apparatus 10 described with reference to FIG. That is, the substrate S to be processed in FIG. Then, a capacitor insulating film made of a hafnium silicate film is formed on the hard mask 22 so as to cover the inner wall of the trench 23 of the substrate 21 by ALD.

  In the present invention, since the pressure of the processing atmosphere is temporarily changed during the purge process, the formation of this capacitor insulating film is based on the flowchart of FIG. 3 and the graph of the pressure fluctuation in the processing chamber 11 shown in FIG. Will be described. Note that the pressure in the processing chamber 11 here corresponds to the pressure in the processing atmosphere. Each configuration of the ALD apparatus used for the film formation is shown in FIG. In addition, the total flow rate of each gas in each process is constant unless otherwise specified.

First, the temperature of the substrate 21 is set to 300 ° C. to 400 ° C. by heating the stage 12, and the pressure in the processing chamber 11 is set to 266 Pa, for example (FIG. 4). Then, after the temperature of the substrate 21 becomes stable, a source gas (Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ ) containing hafnium (Hf) atoms is supplied from the source gas supply pipe 15. At the same time, a source gas (Si [N (CH ₃ ) (C ₂ H ₅ )] ₄ ) containing silicon (Si) atoms is supplied from the source gas supply pipe 16 for 5 seconds (S101).

As a result, H in the NH ₂ group at the end of the inner wall surface of the trench 23 is a source gas component, Hf [N (CH ₃ ) (C ₂ H ₅ )] ₃ or Si [N (CH ₃ ) (C ₂ H ₅ )] Substituted by ₃ and chemically adsorbed on the nitrogen atom (N). For this reason, a layer composed of Hf atoms or Si atoms is formed on the inner wall surface of the trench 13, and N-ethylmethylamine (C ₂ H ₅ NHCH ₃ ) is generated as a reaction product.

  Here, the source gas containing Hf atoms and the source gas containing Si atoms are supplied in the same step, but the source gas containing Hf atoms and the source gas containing Si atoms are the same. One may be supplied first. For example, when the source gas containing Hf atoms is supplied first, the purge process, the oxidizing gas supply process, and the purge process are sequentially performed, and then the source gas containing Si atoms is supplied and purged. A process, an oxidizing gas supply process, and a purge process are sequentially performed. As a result, the Hf oxide layer and the Si oxide layer are alternately formed in a laminate.

After supplying the source gas as described above, an inert gas composed of Ar is supplied into the processing chamber 11 for 5 seconds to purge the unreacted source gas (S102). This purge also removes the reaction product. As will be described later, since the supply of the oxidizing gas performed in the next process is performed at 532 Pa, for example, the opening degree of the valve 13a of the exhaust pipe 13 is adjusted during the 5-second purge process, and the processing chamber 11 The pressure inside reaches 532 Pa (FIG. 4). Although an inert gas made of Ar is used here, other inert gases such as helium (He), neon (Ne), nitrogen (N ₂ ), hydrogen (H ₂ ), etc. may be used. Good. In the present invention, nitrogen (N ₂ ) and hydrogen (H ₂ ) are also included in the inert gas.

Next, an oxidizing gas made of, for example, O _{3 is} supplied into the processing chamber 11 for 5 seconds using O ₂ as a carrier gas (S103). At this time, as will be described later, in order to insert a temporary pressurizing step in the next purging step (S104), for example, a cylinder connected to the inert gas supply pipe 18 during the O ₃ gas supply step (S103). The valve 18a (not shown) is opened, and the inside of the inert gas supply pipe 18 is kept pressurized by closing the valve 18c.

As described above, when the O ₃ gas is supplied to the processing surface of the substrate 21, the source gas components (Hf [N (CH ₃ ) (C ₂ H ₅ )] ₃ , adsorbed on the inner wall surface of the trench 23 are obtained. The methylethylamino group (N (CH ₃ ) (C ₂ H ₅ )) of Si [N (CH ₃ ) (C ₂ H ₅ )] ₃ )) is substituted with an oxygen (O) atom, respectively. As a result, a layer of O atoms adsorbed on Hf atoms and Si atoms is formed on the inner wall surface of the trench 23, and a layer containing Hf oxide and Si oxide is formed. At this time, N-ethylmethylamine (C ₂ H ₅ NHCH ₃ ) is generated as a reaction product.

Here, O ₃ is used as the oxidizing gas, but any compound that can form a layer of O atoms by reacting with the raw material gas components may be used. Hydrogen peroxide (H ₂ O ₂ ), water It may be (H ₂ O) or heavy water (D ₂ O).

  Next, an inert gas composed of Ar is supplied into the processing chamber 11 for 5 seconds to purge unreacted oxidizing gas (S104). This purge also removes the reaction product. At this time, a step of temporarily changing the pressure in the processing chamber 11 is inserted. In the present embodiment, the pressure in the processing chamber 11 is temporarily increased. This temporary pressurizing step refers to a step of, for example, returning to a pressure close to the original pressure after pressurizing 200 Pa or more in one second.

In the present embodiment, since the valve of the cylinder 18a is opened and only the valve 18c is closed in the O ₃ gas supply step (S103) described above, Ar filled in the inert gas supply pipe 18 is treated. The chamber 11 is supplied at a high flow rate, and the inside of the processing chamber 11 is temporarily pressurized. Here, for example, the pressure in the processing chamber 11 is temporarily increased approximately twice, that is, from about 532 Pa to about 1064 Pa (FIG. 4). As a result, Ar gas is sprayed onto the processing surface of the substrate 21, that is, the hard mask 22 including the inner wall surface of the trench 23, and unreacted source gas and oxidizing gas inside the trench 23 are purged and removed. . Thereafter, since the supply of Ar gas is within the set flow rate, the pressure in the processing chamber 11 is also reduced to 532 Pa (FIG. 4).

Next, as will be described later, since the supply of the source gas performed in the next step is performed at 266 Pa, for example, the opening degree of the valve 13a of the exhaust pipe 13 is adjusted during the purge step (S104), and the inside of the processing chamber 11 It is assumed that the pressure reaches 266 Pa (FIG. 4). Here, although Ar is used as the inert gas, it is possible to use He, Ne, N ₂ , H ₂ or the like as in the first purge step described above.

  Here, the temporary pressurization process is inserted only during the purge process (S104), but the same temporary pressurization is performed in the purge process (S102) after the source gas supply process (S101). A process may be inserted. However, in the purge step (S102), when performing a temporary pressurization step, although the purge efficiency is improved, Hf atoms and Si atoms in a state where O atoms are not bonded are easily separated by purge, The film formation rate of Hf atoms or Si atoms is reduced. For this reason, it is preferable to insert the pressurizing step only during the purge step (S104) after the oxidizing gas supply step (S103).

  Thereafter, the source gas supply step (S101) to the purge step (S104) are repeated a plurality of times. The number of repetitions is, for example, that the film thickness of the thin film to be formed is checked in advance by performing the source gas supply process (S101) to the purge process (S104) once, and the film thickness and the film thickness to be formed. Based on and. Then, the above process is repeated for the calculated number of times, and it is determined whether or not the film is formed with a predetermined film thickness. As a result, if the film is formed to a predetermined film thickness, the process is terminated. If the film thickness is equal to or smaller than the predetermined film thickness, the above process is repeated.

As a result, as shown in FIG. 5, a capacitor insulating film 24 made of hafnium silicate having a desired film thickness is formed on the hard mask 22 so as to cover the inner wall surface of the trench 23. Thereafter, ammonia gas (NH ₃ ) is supplied into the processing chamber 11, heat treatment is performed, and the capacitor insulating film 24 is nitrided.

  The subsequent steps are performed in the same manner as in a normal trench capacitor forming method. That is, a trench capacitor is formed by forming an upper electrode (not shown) made of, for example, polysilicon on the capacitor insulating film 24 in a state where the trench 23 is embedded.

  According to such a method for forming a thin film, the pressure in the processing atmosphere is changed by temporarily increasing the supply amount of Ar gas during the purging step (S104) and applying pressure. The raw material gas, oxidizing gas, and reaction product of the reaction are easily removed. Thereby, since the purge efficiency can be increased, the concentration of impurities such as carbon (C) and hydrogen (H) due to the source gas in the film is reduced. Therefore, leakage current through the trap level due to impurities is suppressed, and the yield of devices to be manufactured can be improved.

  Further, since the reaction between the remaining raw material gas and the oxidizing gas in the gas phase is prevented, the generation of particles can be prevented, so that the contamination of the ALD apparatus 10 can be prevented. Furthermore, since the reaction in the gas phase is prevented, consumption of the source gas and oxidizing gas to be supplied in the gas phase is prevented, so that the source gas and the oxidizing gas are also applied to the bottom surface of the trench 23. The coverage can be improved.

  Further, the purge efficiency is increased, so that the purge process (S104) that has been conventionally performed for 10 seconds can be shortened to, for example, 5 seconds. Therefore, throughput can be improved.

  In the present embodiment, the temporary pressurizing step is inserted once, but may be inserted a plurality of times. The greater the number of insertions, the higher the purge efficiency. In this case, in the second and subsequent pressurization steps, the Ar gas flow rate is temporarily increased by the flow rate regulator 18c. However, this pressurization process is performed in the number of times that can be performed in the purge process for several seconds.

  In the present embodiment, an example using a single-wafer type ALD apparatus has been described. However, the present invention can be applied to a batch type apparatus that processes a plurality of wafers at a time. In this case, it is preferable to insert a plurality of pressurizing steps because the purge time can be increased by processing a plurality of wafers at a time as compared with a single wafer type ALD apparatus.

(Second Embodiment)
In the present embodiment, an example in which a temporary depressurization step is inserted during the purge step will be described based on the flowchart of FIG. 3 and using a graph of pressure fluctuation in the processing chamber 11 shown in FIG. Note that, except for the purge step (S104), the same method as in the first embodiment is performed. The configuration of the ALD apparatus used for film formation is shown in FIG.

  In this case, as shown in FIG. 6, Ar gas is supplied for 5 seconds in the purge step (S104), and the vacuum pump 14 is operated during the purge step (S104) for 5 seconds. By continuously changing the opening of the valve 13a of the exhaust pipe 13, the pressure in the processing chamber 11 is changed from the pressure 532Pa in the processing chamber 11 in the oxidizing gas supply step (S103), which is the previous step, to the following. The pressure is reduced to 266 Pa in the source gas supply step (S101).

  Further, a step of temporarily changing the pressure in the processing chamber 11 is inserted during the purge step (S104). In the present embodiment, the pressure in the processing chamber 11 is temporarily reduced. This temporary depressurization step refers to a step of depressurizing 200 Pa or more for 1 second and then returning to a pressure close to the original pressure. Specifically, the supply of Ar gas is shut off by closing the valve 18c of the inert gas supply pipe 18. Thereby, the pressure in the processing chamber 11 is temporarily reduced to 66 Pa. Next, the valve 18c is opened and Ar gas is supplied again. At this time, as described above, the opening of the valve 13a is changed so as to gradually reduce the pressure in the processing chamber 11, and the pressure in the processing chamber 11 is increased to about 400 Pa.

  Subsequently, the supply of Ar gas is shut off by closing the valve 18c, so that the pressure in the processing chamber 11 is temporarily reduced to 66 Pa again, and then the valve 18c is opened to supply Ar gas. At this time, as described above, the opening of the valve 13a is changed so as to gradually reduce the pressure in the processing chamber 11, and the pressure in the processing chamber 11 is changed to the source gas supply step (S101) performed in the next step. The pressure is increased to 266 Pa. Then, the hafnium silicate film having a desired film thickness is formed by repeatedly performing the source gas supply step (S101) to the purge step (S104). The subsequent steps are performed in the same manner as in the first embodiment.

  According to such a method for forming a thin film, the temporary depressurization step is inserted twice during the purge step (S104), so that the exhaust of the gas in the processing chamber 11 is promoted. And the oxidizing gas are easily removed, and the purge efficiency is increased. Thereby, there can exist an effect similar to 1st Embodiment.

  Here, the temporary pressure reduction step is inserted only in the purge step (S104) after the oxidizing gas supply step (S103), but the purge step (S102) after the source gas supply step (S101). ) A similar decompression step may be inserted. However, in the purge step (S102), when a temporary pressure reduction step is performed, the purge efficiency is increased as described in the first embodiment, but the deposition rate of Hf atoms or Si atoms is reduced. Therefore, it is preferable to insert the decompression step only during the purge step (S104) after the oxidizing gas supply step (S103).

  In the present embodiment, the temporary decompression step is inserted twice, but it may be performed once or three or more times. The greater the number of insertions, the higher the purge efficiency. However, this depressurization step is performed in the number of times that can be performed in a purge step of several seconds.

  In the first embodiment and the second embodiment described above, the example in which the hafnium silicate film is formed by the ALD method has been described. However, the present invention is not limited to this, and other metals such as an aluminum silicate film and a zirconium silicate film are used. It may be a silicate film or a metal oxide film such as hafnium oxide, aluminum oxide, zirconium oxide or the like.

  Furthermore, in the first embodiment and the second embodiment, the pressure in the processing chamber 11 is changed in the source gas supply step (S101) and the oxidizing gas supply step (S103), but the pressure is, for example, 532 Pa. It may be constant. In this case, all the processes except the temporary pressure fluctuation process are performed at the same pressure.

  In the first embodiment and the second embodiment, the example in which the capacitor insulating film is formed in the trench of the trench capacitor has been described. However, the present invention is not limited to this, and the fin-type or crown-type unevenness is formed. The present invention is applicable even when the capacitor insulating film is formed so as to cover the lower electrode. Further, the present invention can be applied even when a gate insulating film made of a high-k material is formed on a silicon substrate or when a capacitor insulating film is formed on a flat plate. Among the above, according to the thin film forming method of the present invention, the coverage can be improved, so that the unevenness as in the case of forming the capacitor insulating film in the manufacturing process of the trench type, fin type or crown type capacitor can be performed. It can be suitably used when a thin film is formed on the treated surface having

It is a block diagram of the ALD apparatus used for embodiment which concerns on the formation method of the thin film of this invention. It is sectional drawing for demonstrating 1st Embodiment which concerns on the formation method of the thin film of this invention. It is a flowchart for demonstrating 1st Embodiment which concerns on the formation method of the thin film of this invention. It is a graph which shows the time-dependent pressure fluctuation of the process atmosphere of 1st Embodiment which concerns on the formation method of the thin film of this invention. It is sectional drawing for demonstrating 1st Embodiment which concerns on the formation method of the thin film of this invention. It is a graph which shows the time-dependent pressure fluctuation of the process atmosphere of 1st Embodiment which concerns on the formation method of the thin film of this invention.

Explanation of symbols

  21 ... Substrate, 23 ... Trench, 24 ... Capacitor insulating film

Claims (6)

A first step of forming a layer containing at least one of metal atoms and silicon atoms by supplying a source gas containing at least one of metal atoms and silicon atoms to the processing atmosphere and adsorbing the source gas component on the processing surface of the substrate. When,
A second step of supplying an inert gas to the processing atmosphere and purging the source gas in the processing atmosphere;
A third step of supplying an oxidizing gas to the processing atmosphere and reacting with the source gas component adsorbed on the processing surface of the substrate to form a layer of oxygen atoms;
A fourth step of supplying an inert gas to the processing atmosphere and purging the oxidizing gas in the processing atmosphere;
In the method of forming a thin film using an atomic layer deposition method in which a thin film is formed on the treated surface by repeatedly performing the first step to the fourth step,
A method of forming a thin film, wherein a step of temporarily changing the pressure of a processing atmosphere is inserted into at least one of the second step and the fourth step. The method for forming a thin film according to claim 1,
The method of temporarily changing the pressure of the processing atmosphere is performed by temporarily increasing the amount of inert gas supplied to the processing surface and pressurizing the thin film. The method for forming a thin film according to claim 1,
The method of forming a thin film, wherein the step of temporarily changing the pressure of the processing atmosphere is performed by temporarily reducing the pressure. The method for forming a thin film according to claim 1,
Only in the fourth step, the pressure of the processing atmosphere is temporarily changed. The method for forming a thin film according to claim 1,
The method for forming a thin film, wherein the treatment surface has irregularities. The method for forming a thin film according to claim 1,
A method of forming a thin film, comprising: forming the thin film using a single-wafer apparatus.

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