JP5839514B2 - Film forming method, film forming apparatus, and method of using film forming apparatus - Google Patents

Description

The present invention relates to a film formation method, a film formation apparatus, and a method of using the film formation apparatus for forming a silicon oxide film (SiO ₂ film) on an object to be processed using a Si source gas and an oxidizing species, and in particular, a semiconductor processing technique. About. Here, the semiconductor processing means that a semiconductor layer, an insulating layer, a conductive layer, and the like are formed in a predetermined pattern on a target object such as a semiconductor wafer or a glass substrate for an FPD (Flat Panel Display) such as an LCD (Liquid Crystal Display). This means various processes performed to manufacture a structure including a semiconductor device, a wiring connected to the semiconductor device, an electrode, and the like on the object to be processed.

In the semiconductor device manufacturing sequence, there is a process of forming a SiO ₂ film on a semiconductor wafer typified by a silicon wafer (hereinafter sometimes simply referred to as a wafer). For such a SiO ₂ film forming process, a vertical batch type film forming apparatus is often used, and a plurality of semiconductors to be processed by chemical vapor deposition (CVD) using Si source gas and oxidizing species. A SiO ₂ film is formed on the wafer at once.

In recent years, with the progress of miniaturization and integration of semiconductor devices, it has been required to form a SiO ₂ film having good quality characteristics at a low temperature of 400 ° C. or lower. As a technique capable of realizing this, SiO layer is formed by using ALD (Atomic Layer Deposition), in which layers of an atomic layer level or molecular layer level are stacked while alternately supplying Si source gas and oxidizing species. A technique for forming _two films has been proposed (for example, Patent Document 1).

In such a SiO ₂ film forming process using CVD or ALD, the film forming process is repeatedly performed on a plurality of wafers. For example, in a vertical batch type heat treatment apparatus, a wafer boat carrying one batch of wafers is carried into a processing container and film formation is performed. Next, another (or the same) wafer boat on which another batch of wafers is loaded is carried into a processing container to perform a film forming process. In this way, the film forming process is repeated a plurality of times.

  However, when such a film forming process is repeated a plurality of times and the film thickness of the film deposited on the inner wall of the processing container increases, a phenomenon occurs in which the number of particles adhering to the wafer suddenly increases. In particular, such a problem becomes remarkable in the case of ALD in which film formation is performed at a low temperature.

  As techniques for modifying the film deposited on the inner wall of the processing container to suppress the generation of particles due to film peeling, there are those disclosed in Patent Document 2 and Patent Document 3.

Japanese Patent Laid-Open No. 2003-7700 JP 2006-351948 A JP 2008-140864 A

However, Patent Documents 2 and 3 do not solve the problem of particles in the film forming process of the SiO ₂ film using CVD or ALD.

Therefore, an object of the present invention is to reduce the number of particles adhering to the object to be processed when the SiO ₂ film forming process on the object to be processed is repeatedly performed using the Si source gas and the oxidizing species.

As a result of studying the above problems in the course of development of the present invention, the present inventors have found the following points. That is, when forming the SiO ₂ film to the object to be processed with an oxidizing species and Si source gas, a SiO ₂ film is also deposited on the inner wall of the processing container. The SiO ₂ film deposited on the inner wall of the processing vessel, particularly the portion outside the processing region, also contains unreacted Si-containing material, and such Si-containing material is generated as outgas during the film forming process. When the SiO ₂ film deposited on the inner wall of the processing container becomes thicker by repeatedly performing the film forming process, the Si-containing material generated as outgas during the film forming process increases rapidly. Thus, particles are generated by the gas phase reaction between the Si-containing material generated as outgas and the oxidizing species, and these particles adhere to the object to be processed.

The first aspect of the present invention is to supply the diisopropylaminosilane (DIPAS) gas as the Si source gas into the processing vessel, supply the plasma of the oxygen-containing gas as the oxidizing species, and use room temperature as the processing temperature. A film forming method for performing a film forming process for forming a SiO ₂ film on a surface of an object to be processed in a container, wherein the object to be processed is placed between the preceding film forming process and the next film forming process. In the state of being carried out from the processing container, supplying the plasma of the oxygen-containing gas without supplying the DIPAS gas into the processing container while evacuating the processing container, and using room temperature as the processing temperature , An oxidation purge process is performed in which oxidation is performed to reduce the amount of aminosilane remaining in the by-product deposited in the processing vessel .

  A second aspect of the present invention is a film forming apparatus, which is a vertical processing container that can be held in vacuum, a holding member that holds a plurality of objects to be processed in multiple stages in the processing container, A loading / unloading mechanism for loading / unloading the holding member into / from the processing container; a source gas supply mechanism for supplying diisopropylaminosilane (DIPAS) gas as an Si source gas into the processing container; and an oxygen-containing gas into the processing container. An oxygen-containing gas supply mechanism to supply; a plasma generation mechanism that converts the oxygen-containing gas attached to the processing vessel into plasma; an exhaust system that exhausts the inside of the processing vessel; and a control mechanism that controls the operation of the apparatus. And the control mechanism controls the operation of the apparatus so that the film forming method according to the first aspect is executed.

A third aspect of the present invention is a method of using a film forming apparatus, the method of using the film forming apparatus, wherein the film forming apparatus includes a vertical processing container capable of maintaining a vacuum and a processing container in the processing container. A holding member that holds a plurality of objects to be processed in a multi-stage state, a source gas supply system that supplies diisopropylaminosilane (DIPAS) gas as an Si source gas into the processing container, and an oxygen-containing gas into the processing container An oxygen-containing gas supply system for supplying gas, a plasma generation mechanism for converting the oxygen-containing gas attached to the processing vessel into plasma, and an exhaust system for exhausting the inside of the processing vessel. In the film formation process, room temperature is used as the film formation process temperature in the process container, and the DIPA is supplied from the source gas supply system into the process container while exhausting the process container by the exhaust system. A step of supplying a gas; a step of supplying the oxygen-containing gas from the oxygen-containing gas supply system into the processing vessel while exhausting the inside of the processing vessel by the exhaust system; and Supplying the oxygen-containing gas while turning it into plasma, and oxidizing the substance derived from the DIPAS gas with the radicals derived from the oxygen-containing gas generated thereby to form the silicon oxide film;
Between the preceding film forming process and the next film forming process, while the object to be processed is carried out of the processing container, the process container is evacuated and the process container is evacuated. Oxidation is performed to reduce the amount of aminosilane remaining in the by-product deposited in the processing vessel by supplying plasma of the oxygen-containing gas without supplying DIPAS gas and using room temperature as the processing temperature. The oxidation purge process is performed.

According to the present invention, the oxidation purge process is performed while the object to be processed is unloaded from the processing container during the film formation process of the SiO ₂ film using the Si source gas and the oxidizing species. In this case, the amount of Si source gas released from the film deposited on the inner wall of the processing vessel can be reduced, and the number of particles on the object to be processed can be reduced.

It is sectional drawing which shows the film-forming apparatus (vertical plasma ALD apparatus) which concerns on embodiment of this invention. It is a cross-sectional top view which shows a part of apparatus shown in FIG. It is a figure for demonstrating the film-forming method which concerns on embodiment of this invention. 4 is a timing chart showing gas supply timings in the film forming process of the film forming method of FIG. 3. The relationship between the number of particles of 0.05 μm or more on the wafer and the number of times of film formation (cumulative film thickness) is shown when ALD is used as the Si source gas and O ₂ plasma is used as the oxidizing species and the film formation is repeated by ALD. FIG. FIG. 6 is a diagram illustrating the relationship between the number of fine particles of 0.05 to 0.2 μm and the number of film formation (cumulative film thickness) in FIG. 5. Si is a schematic view showing a state of forming the SiO ₂ film by ALD process using O ₂ plasma as the aminosilane with oxidizing species as a source gas. When an SiO ₂ film is formed on a wafer by ALD using aminosilane and O ₂ plasma, the O ₂ plasma flow time is short and long, and further, C in the SiO ₂ film formed by thermal oxidation It is a figure which shows a density | concentration. When forming an SiO ₂ film on the wafer by ALD using the aminosilane and O ₂ plasma, O ₂ as the plasma flow time is short and long, more N in the film of the SiO ₂ film formed by thermal oxidation It is a figure which shows a density | concentration. In FIG. 10A, a SiO ₂ film having a thickness of about 30 nm is formed on a wafer by ALD using aminosilane and O ₂ plasma, and then a cycle purge using N ₂ gas is performed without unloading the wafer. It is a figure which shows the sequence which repeated these 4 times. FIG. 10B is a diagram showing a sequence in which purging (oxidation purge) using O ₂ plasma is performed instead of the cycle purge in the sequence of FIG. 10A. FIGS. 11A, 11B, and 11C are diagrams showing analysis results of carbon / nitrogen compounds in the SiO ₂ film formed by the sequence of FIGS. 10A and 10B. It is a figure which shows the image and analysis result of the SEM photograph of the particle | grains exceeding 0.2 micrometer on a wafer. It is a figure which shows the image and analysis result of the SEM photograph of the particle | grains of 0.2 micrometer or less on a wafer. FIGS. 14A and 14B are schematic views showing the state in the processing container when the SiO ₂ film is formed by the conventional method and the method according to the embodiment of the present invention. It is a figure for demonstrating the experiment for comparing the conventional method and the method which concerns on embodiment of this invention. It is a figure which shows the number of the particles of 0.05 micrometer or more on a wafer at the time of performing the conventional method and the method which concerns on embodiment of this invention. It is a figure which shows the number of particles more than 0.2 micrometer among the particles of FIG. It is a figure which shows the number of 0.05-0.2 micrometer particles among the particles of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.
FIG. 1 is a sectional view showing a film forming apparatus (vertical plasma ALD apparatus) according to an embodiment of the present invention. FIG. 2 is a cross-sectional plan view showing a part of the apparatus shown in FIG. In FIG. 2, the heating mechanism is omitted.

The film forming apparatus 100 is for forming a SiO ₂ film with Si source gas and oxidizing species, and has a cylindrical processing container 1 having a ceiling with an open lower end. The entire processing container 1 is made of, for example, quartz, and a quartz ceiling plate 2 is provided in the vicinity of the upper end portion in the processing container 1, and a lower region thereof is sealed. In addition, a manifold 3 formed in a cylindrical shape from, for example, stainless steel is connected to the lower end opening of the processing container 1 via a seal member 4 such as an O-ring.

  The manifold 3 supports the lower end of the processing vessel 1, and a quartz wafer boat 5 on which a large number of, for example, 50 to 100 semiconductor wafers W can be placed in multiple stages as objects to be processed from below the manifold 3. Can be inserted into the processing container 1. The wafer boat 5 has three columns 6 (see FIG. 2), and a large number of wafers W are supported by grooves formed in the columns 6.

  The wafer boat 5 is placed on a table 8 via a quartz heat insulating cylinder 7, and the table 8 passes through a lid 9 made of, for example, stainless steel that opens and closes the lower end opening of the manifold 3. It is supported on the rotating shaft 10.

  And the magnetic fluid seal | sticker 11 is provided in the penetration part of this rotating shaft 10, for example, and the rotating shaft 10 is supported rotatably, sealing airtightly. Further, a sealing member 12 made of, for example, an O-ring is interposed between the peripheral portion of the lid portion 9 and the lower end portion of the manifold 3, thereby maintaining the sealing performance in the processing container 1.

  The rotary shaft 10 is attached to the tip of an arm 13 supported by an elevating mechanism (not shown) such as a boat elevator, for example, and moves up and down the wafer boat 5 and the lid 9 etc. integrally. 1 is inserted into and removed from the inside. The table 8 may be fixedly provided on the lid 9 side, and the wafer W may be processed without rotating the wafer boat 5.

In addition, the film forming apparatus 100 includes the oxygen-containing gas supply mechanism 14 that supplies an oxygen-containing gas, for example, O ₂ gas, and the processing container 1 to generate oxygen-containing plasma as an oxidizing species in the processing container 1. A Si source gas supply mechanism 15 for supplying Si source gas, a purge gas supply mechanism 16 for supplying an inert gas such as N ₂ gas into the processing container 1 as a purge gas, and a cleaning gas such as HF gas or the like into the processing container 1 And a cleaning gas supply mechanism 41 for supplying a fluorine-containing gas such as F ₂ gas.

The oxygen-containing gas supply mechanism 14 is connected to the oxygen-containing gas supply source 17, a gas pipe 18 that guides the oxygen-containing gas from the gas supply source 17, and the gas pipe 18. And a gas dispersion nozzle 19 made of a quartz tube bent in the direction and extending vertically. A plurality of gas discharge holes 19 a are formed in the vertical portion of the gas dispersion nozzle 19 at a predetermined interval over the length in the vertical direction corresponding to the wafer support range of the wafer boat 5. An oxygen-containing gas, for example, O ₂ gas, can be discharged from each gas discharge hole 19a toward the processing container 1 in a horizontal direction substantially uniformly.

  The Si source gas supply mechanism 15 is connected to the Si source gas supply source 20, a gas pipe 21 that guides the Si source gas from the gas supply source 20, and the gas pipe 21, and penetrates the side wall of the manifold 3 inward. And a gas dispersion nozzle 22 made of a quartz tube bent in a direction and extending vertically. Here, two gas dispersion nozzles 22 are provided (see FIG. 2), and a plurality of vertical portions corresponding to the wafer support range of the wafer boat 5 are also provided in the vertical portion of each gas dispersion nozzle 22. Gas discharge holes 22a are formed at a predetermined interval. Si source gas can be discharged substantially uniformly into the processing container 1 in the horizontal direction from each gas discharge hole 22a. Note that only one gas dispersion nozzle 22 may be provided.

The purge gas supply mechanism 16 includes a purge gas supply source 23, a gas pipe 24 that guides the purge gas from the gas supply source 23, and a gas nozzle that is connected to the gas pipe 24 and is formed of a short quartz tube that passes through the side wall of the manifold 3. 25. As the purge gas, an inert gas such as N ₂ gas can be preferably used.
The cleaning gas supply mechanism 41 includes a cleaning gas supply source 42 and a gas pipe 43 extending from the gas supply source 42. The gas pipe 43 branches in the middle and is connected to the gas pipe 18 and the gas pipe 21.

  The gas pipes 18, 21, 24, 43 are provided with on-off valves 18a, 21a, 24a, 43a and flow controllers 18b, 21b, 24b, 43b such as a mass flow controller, respectively. As a result, the oxygen-containing gas, the Si source gas, the purge gas, and the cleaning gas can be supplied while controlling their flow rates.

A plasma generation mechanism 30 is formed on a part of the side wall of the processing vessel 1 to convert the oxygen-containing gas into plasma to form oxygen-containing plasma as an oxidizing species. This plasma generation mechanism 30 is airtight on the outer wall of the processing container 1 so as to cover the opening 31 formed vertically from the outside by scraping the side wall of the processing container 1 with a predetermined width along the vertical direction. And has a plasma compartment wall 32 welded thereto. The plasma partition wall 32 has a concave cross-sectional shape and is elongated vertically, and is made of, for example, quartz.
The plasma generation mechanism 30 includes a pair of elongated plasma electrodes 33 disposed on the outer surfaces of both side walls of the plasma partition wall 32 so as to face each other in the vertical direction, and a power supply line 34 provided to the plasma electrode 33. And a high frequency power supply 35 for supplying high frequency power. Then, by applying a high frequency voltage of 13.56 MHz, for example, from the high frequency power supply 35 to the plasma electrode 33, plasma of oxygen-containing gas can be generated. Note that the frequency of the high-frequency voltage is not limited to 13.56 MHz, and other frequencies such as 400 kHz may be used.

  By forming the plasma partition wall 32 as described above, a part of the side wall of the processing container 1 is recessed outward in the shape of a recess, and the internal space of the plasma partition wall 32 is integrated with the internal space of the processing container 1. Will be in a state of communication. The internal space of the plasma partition wall 32 and the opening 31 are formed long enough in the vertical direction so that all the wafers W held by the wafer boat 5 can be covered in the height direction.

  The gas dispersion nozzle 19 for the oxygen-containing gas is bent outward in the radial direction of the processing container 1 in the middle of extending upward in the processing container 1, and is the innermost part (processing container) in the plasma partition wall 32. (The portion farthest from the center of 1)). Therefore, when the high frequency power supply 35 is turned on and a high frequency electric field is formed between the electrodes 33, the oxygen-containing gas injected from the gas injection holes 19a of the gas dispersion nozzle 19 is turned into plasma and the center of the processing vessel 1 It flows while diffusing towards.

  An insulating protective cover 36 made of, for example, quartz is attached to the outside of the plasma partition wall 32 so as to cover it. Further, a refrigerant passage (not shown) is provided in an inner portion of the insulating protective cover 36, and the plasma electrode 33 can be cooled by flowing a cooled nitrogen gas, for example.

  The two gas distribution nozzles 22 of the Si source gas are provided upright at a position sandwiching the opening 31 on the inner wall of the processing container 1. Si source gas can be discharged toward the center of the processing container 1 from the plurality of gas injection holes 22 a formed in the gas dispersion nozzle 22.

  On the other hand, an exhaust port 37 for evacuating the inside of the processing container 1 is provided at a portion opposite to the opening 31 of the processing container 1. The exhaust port 37 is formed in an elongated shape by scraping the side wall of the processing container 1 in the vertical direction. An exhaust port cover member 38 having a U-shaped cross section so as to cover the exhaust port 37 is attached to a portion corresponding to the exhaust port 37 of the processing container 1 by welding. The exhaust port cover member 38 extends upward along the side wall of the processing container 1, and defines a gas outlet 39 above the processing container 1. The gas outlet 39 is evacuated by an evacuation mechanism VEM including a vacuum pump and the like. Further, a cylindrical heating mechanism 40 for heating the processing container 1 and the wafer W therein is provided so as to surround the outer periphery of the processing container 1.

  Control of each component of the film forming apparatus 100, for example, supply / stop of each gas by opening / closing valves 18a, 21a, 24a, 43a, control of gas flow rate by the mass flow controllers 18b, 21b, 24b, 43b, exhaust by a vacuum exhaust mechanism The control, the on / off control of the high frequency power by the high frequency power source 35, the adjustment of the temperature of the wafer W by the heating mechanism 40, and the like are performed by a controller 50 including, for example, a microprocessor (computer). Connected to the controller 50 is a user interface 51 including a keyboard for an operator to input commands for managing the film forming apparatus 100, a display for visualizing and displaying the operating status of the film forming apparatus 100, and the like. Yes.

  Further, the controller 50 causes each component of the film forming apparatus 100 to execute processes according to a control program for realizing various processes executed by the film forming apparatus 100 under the control of the controller 50 and processing conditions. A storage unit 52 that stores a program for storing the recipe, that is, a recipe, is connected. The recipe is stored in a storage medium in the storage unit 52. The storage medium may be a fixed type such as a hard disk or a semiconductor memory, or may be a portable type such as a CDROM, DVD, or flash memory. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, an arbitrary recipe is called from the storage unit 52 by an instruction from the user interface 51 and is executed by the controller 50, so that a desired process in the film forming apparatus 100 is performed under the control of the controller 50. Is done.

Next, a method for forming a silicon oxide film (SiO ₂ film) according to an embodiment of the present invention performed using the film forming apparatus configured as described above will be described with reference to FIGS. FIG. 3 is a view for explaining the film forming method according to the present embodiment. FIG. 4 is a timing chart showing the gas supply timing in the film forming process of the film forming method according to the present embodiment.

In the present embodiment, as shown in FIG. 3, SiO _{2 is applied} to the wafer W (product wafer) with the wafer boat 5 in a state where, for example, 50 to 100 wafers W are mounted in the processing container 1. The film forming process 201 for forming a film is repeated a plurality of batches, and when the wafer boat 5 is replaced during the film forming process of each batch, the wafer 3 is not carried into the processing container 1 and the lower end of the manifold 3 is opened. An oxidation purge process 202 is performed in which oxygen-containing plasma is generated in the processing container 1 in a closed state and a film (byproduct film) deposited on the inner wall of the processing container 1 is purged while being purged. When the film deposited on the inner wall of the processing container 1 is formed thick by repeating the film forming process 201 10 to 1000 batches, a dry cleaning process is performed to remove the film deposited on the inner wall of the processing container 1. To do.

  In the film forming process 201, first, at room temperature, for example, the wafer boat 5 on which 50 to 100 semiconductor wafers W are mounted is raised from below into the processing container 1 controlled to a predetermined temperature in advance. Then, the inside of the processing container 1 is made a sealed space by closing the lower end opening of the manifold 3 with the lid 9. An example of the semiconductor wafer W is 300 mm in diameter.

  Then, the inside of the processing container 1 is evacuated and maintained at a predetermined process pressure, and the power supplied to the heating mechanism 40 is controlled to increase the wafer temperature and maintain the process temperature at a predetermined temperature of 450 ° C. or lower. . Then, the film forming process is started with the wafer boat 5 rotated. As will be described later, in some cases, the treatment can be performed even at about room temperature. In such a case, the heating mechanism 40 is unnecessary.

As shown in FIG. 4, the film formation process at this time is performed by so-called plasma ALD in which the step S1 and the step S2 are alternately repeated. In step S1, Si source gas is supplied to the processing container 1 and adsorbed onto the wafer W. In step S <b> 2, an oxygen-containing gas that is an oxidizing gas is supplied to generate plasma, and oxygen-containing plasma (oxygen radicals) is generated in the processing container 1 to oxidize the Si source gas adsorbed on the wafer W. Between these steps S1 and S2, steps S3a and S3b for removing the gas remaining in the processing vessel 1 from the processing vessel 1 are performed.
The Si source gas is composed of an aminosilane gas such as trisdimethylaminosilane (3DMAS), tetrakisdimethylaminosilane (4DMAS), bisteria butylaminosilane (BTBAS), diisopropylaminosilane (DIPAS), or the like.

  Specifically, in step S1, the Si source gas is supplied from the gas supply source 20 of the Si source gas supply mechanism 15 through the gas pipe 21 and the gas dispersion nozzle 22 into the processing container 1 from the gas discharge hole 22a. Supply. Thereby, Si source gas is adsorbed on the semiconductor wafer. The period T1 at this time is exemplified by 1 to 180 seconds. Further, the flow rate of the Si source gas is exemplified by 1-1000 mL / min (sccm). Moreover, the pressure in the processing container 1 at this time is exemplified by 13.3 to 1333 Pa (0.1 to 10 Torr).

In step S < _b > _2, for example, O ₂ gas is discharged from the gas supply hole 17 a as the oxygen-containing gas from the gas supply source 17 of the oxygen-containing gas supply mechanism 14 through the gas pipe 18 and the gas dispersion nozzle 19. At this time, if necessary, the high-frequency power source 35 of the plasma generation mechanism 30 is turned on to form a high-frequency electric field, and oxygen-containing gas, for example, O ₂ gas is converted into plasma by this high-frequency electric field. Then, the oxygen-containing gas that has been plasmatized in this way is supplied into the processing vessel 1 as an oxidizing species. Thereby, the Si source gas adsorbed on the wafer W is oxidized to form SiO ₂ . The period T2 of this process is exemplified by a range of 1 to 300 seconds. The flow rate of the oxygen-containing gas varies depending on the number of semiconductor wafers W mounted, but is exemplified by 100 to 20000 mL / min (sccm). The frequency of the high frequency power supply 35 is exemplified as 13.56 MHz, and the power is 5 to 1000 W, preferably 10 to 250 W. Moreover, the pressure in the processing container 1 at this time is 13.3 to 1333 Pa (0.1 to 10 Torr), preferably 13.3 to 120 Pa (0.1 to 0.93 Torr).

In this case, examples of the oxygen-containing gas include O ₂ gas, CO ₂ gas, NO gas, N ₂ O gas, H ₂ O gas, and O ₃ gas. To be used as oxidizing species. As the oxidizing species, O ₂ plasma is preferable. Note that plasma is not necessary when O ₃ gas is used.

Further, in steps S3a and S3b performed between step S1 and step S2, gas remaining in the processing container 1 is removed after step S1 or after step S2 to cause a desired reaction in the next step. It is a process. Here, an inert gas such as N ₂ gas is supplied as a purge gas from the gas supply source 23 of the purge gas supply mechanism 16 through the gas pipe 24 and the gas nozzle 25 while evacuating the inside of the processing container 1. Examples of the periods T3a and T3b of the steps S3a and S3b include 1 to 60 sec. The purge gas flow rate is exemplified by 50 to 20000 mL / min (sccm). Note that, in steps S3a and S3b, if the gas remaining in the processing container 1 can be removed, the evacuation is continuously performed with the supply of all gases stopped without supplying the purge gas. May be. However, the residual gas in the processing container 1 can be removed in a short time by supplying the purge gas. The pressure in the processing container 1 at this time is exemplified by 13.3 to 1333 Pa (0.1 to 10 Torr).

In this way, the step S1 of intermittently supplying the Si source gas with the steps S3a and S3b of removing the residual gas from the processing vessel 1 and the step S2 of supplying the oxygen-containing plasma containing oxygen radicals alternately and intermittently. By repeating, a thin SiO ₂ film can be repeatedly deposited one by one to obtain a predetermined thickness. The number of repetitions at this time is appropriately determined depending on the thickness of the SiO ₂ film to be obtained.

  The oxidation purge process is performed after the film formation process is completed and the wafer boat 5 loaded with the processed wafers W is unloaded from the process container 1. The oxidation purge process is an idling state of the apparatus during the time when a batch of wafers W to be subjected to a film forming process is carried into the processing container 1 after the batch of wafers W after the film forming process is completed. Can be done inside. The idling state of this apparatus is an operation for preparing the wafer W of the next batch on the wafer boat 5, for example, movement of the wafer W of the processed batch from the periphery of the apparatus, a predetermined position around the apparatus of the wafer W of the next batch This is indispensable in the operation of the apparatus for moving to the next step, loading the next batch of wafers W onto the wafer boat 5, and the like. Therefore, by performing the oxidation purge process during the idling state of such an apparatus, it is possible to prevent an increase in apparatus downtime.

In this oxidation purge process, first, an inert gas such as N ₂ gas is supplied as a purge gas from the purge gas supply source 23 of the purge gas supply mechanism 16 through the gas pipe 24 and the gas nozzle 25 while evacuating the inside of the empty processing container 1. Then, the residual gas in the processing container 1 is purged. Next, the inside of the processing container 1 is evacuated to about 0.133 to 1333 Pa (0.001 to 10 Torr). Then, for example, O ₂ gas is discharged from the gas supply source 17 of the oxygen-containing gas supply mechanism 14 as an oxygen-containing gas from the gas discharge hole 19 a through the gas pipe 18 and the gas dispersion nozzle 19.
At this time, if necessary, the high-frequency power source 35 of the plasma generation mechanism 30 is turned on to form a high-frequency electric field, and oxygen-containing gas, for example, O ₂ gas is converted into plasma by this high-frequency electric field. Then, the oxygen-containing gas that has been plasmatized in this way is supplied into the processing vessel 1 as an oxidizing species. Thus, oxidation is performed on the by-product film containing the reactive Si-containing material that is deposited in the processing container 1 and causes generation of particles in the film forming process. The oxidation time in this oxidation purge process is preferably 60 to 3600 seconds. The oxygen-containing gas, other _{O 2} gas, CO ₂ gas, NO gas, _{N 2} O gas, there may be mentioned _{H 2} O gas, _{O 3} gas, into a plasma by a high frequency electric field in accordance with these necessary Used as oxidizing species. As the oxidizing species, O ₂ plasma is preferable. Note that plasma is not necessary when O ₃ gas is used.

After the film forming process as described above is repeated for a predetermined number of batches of wafers W, a cleaning process for removing the by-product film deposited in the processing container 1 is performed. For example, in this cleaning process, after the accumulated film thickness of the SiO ₂ film (silicon oxide film) reaches a predetermined value within 2 to 5 μm by repeating the film forming process, the film forming process is performed on the wafer W of the next batch. Do before. The cumulative film thickness used for determining the timing of the cleaning process may be a theoretical value obtained by integrating the thicknesses of the SiO ₂ films formed in one film forming process defined by the film forming process recipe. it can. Instead, the cumulative film thickness is a value obtained by actually measuring the thickness of the SiO ₂ film formed on the monitor wafer by loading a monitor wafer together with the product wafer W on the wafer boat 5 in the film formation process. The integrated measurement value can also be used.
In the cleaning process, the wafer boat 5 on which product wafers are not mounted in the processing container 1 is placed on the heat insulating cylinder 7 and is raised from below in the processing container 1 heated to a predetermined temperature. Load it. Next, the inside of the processing container 1 is made into a sealed space by closing the lower end opening of the manifold 3 with the lid 9. Next, while exhausting the inside of the processing container 1, the cleaning gas is supplied from the cleaning gas supply source 42 through the gas pipes 43, 18, 21 and the gas dispersion nozzles 19, 22, for example, HF gas, F ₂ gas, ClF ₃ gas. A fluorine-containing gas such as is supplied into the processing container 1. Thereby, the reaction product adhering to the inner wall of the processing container 1, the wafer boat 5, the heat insulating cylinder 7, and the gas dispersion nozzles 19 and 22 is removed. The temperature in the processing container 1 during the cleaning process is set to 0 to 600 ° C., preferably 25 to 475 ° C.

  Next, the reason why the above-described oxidation purge process is effective in reducing particles on the wafer W will be described.

In the conventional method, when the SiO ₂ film is formed by the vertical batch type film forming apparatus, the following procedure is repeated. First, film formation is performed on a batch of wafers using a Si source gas and an oxygen-containing gas. Next, after carrying out the batch of wafers together with the wafer boat from the processing container, a purge is performed to supply an inert gas while evacuating the processing container. Next, a film forming process is performed on the subsequent batch of wafers. Next, after carrying out the batch of wafers, the inside of the processing container is purged with an inert gas.

By the film forming process, a SiO ₂ film is deposited on the wafer, and at the same time, a film mainly composed of SiO ₂ is deposited on the inner wall of the processing container. As the film forming process is repeated, the film deposited on the inner wall of the processing container becomes thicker. According to the experiments by the present inventors, it has been found that when the conventional method is used, the number of particles on the wafer increases abruptly when the film deposited on the inner wall of the processing container exceeds a predetermined thickness.
In the experiment, monovalent aminosilane (DIPAS) was used as the Si source gas, and the number of particles of 0.05 μm or more on the wafer was measured when the film formation was repeated by ALD using O ₂ plasma as the oxidizing species. FIG. 5 is a diagram showing the results of this experiment. From this figure, it can be seen that the number of particles increases as the number of film formation increases. FIG. 6 is a diagram showing the relationship between the number of fine particles of 0.05 to 0.2 μm in FIG. 5 and the number of film formation (cumulative film thickness). As shown in FIG. 6, it was found that most of the particles were minute particles in the range of 0.05 to 0.2 μm.

When an SiO ₂ film is formed by an ALD process using amino silane as a Si source gas and O ₂ plasma as an oxidizing species, as described above, amino silane flow → amino silane purge → O ₂ plasma flow → O ₂ plasma purge. Repeat this step. FIG. 7 is a schematic diagram showing a state in which a SiO ₂ film is formed by an ALD process using aminosilane as a Si source gas and O ₂ plasma as an oxidizing species. As shown in FIG. 7, amine is generated during the film formation process. In FIG. 7, R is a hydrocarbon group, and O ^* is an oxygen radical. The reaction at this time can be expressed by a reaction formula such as the following formula (1).
Aminosilane + (O ^* , O ₂ ^* ) → SiO ₂ + Amine ↑ (1)

Therefore, it is presumed that when the SiO ₂ film is deposited on the inner wall of the processing container, an amine-based substance is contained in the film, which contributes to the generation of fine particles of 0.05 to 0.2 μm in some form. The However, since amine is a gas component, it does not adhere to the wafer alone, and the amine itself does not become a solid even if it reacts in a mixed state with oxidizing species.

Next, in the experiment, when the SiO ₂ film is formed on the wafer by ALD in which aminosilane flow → aminosilane purge → O ₂ plasma flow → O ₂ plasma purge is repeated, the O ₂ plasma flow time is short and long. The C concentration and N concentration in the film were measured. For comparison, the C 2 concentration and N concentration of the SiO ₂ film formed by thermal oxidation at 1000 ° C. were similarly measured. The C concentration obtained by these experiments is shown in FIG. 8, and the N concentration is shown in FIG. As shown in these drawings, C concentration and N concentration in the film by extending the ALD of O ₂ plasma flow time (oxidation process time) decreases. However, it has been found that the C concentration and the N concentration are much higher than those of the SiO ₂ film formed by thermal oxidation without using aminosilane. From this, C and N in the film are derived from amine-based materials derived from aminosilane, and such amine-based materials can be reduced to some extent by extending the O ₂ plasma flow time which is an oxidizing species. It was found that it was possible.

Next, an experiment was performed to simulate the state of the film deposited on the inner wall of the processing container. Here, the wafer is carried into the processing container, and a monovalent aminosilane is used as the Si source gas, and an O ₂ plasma is used as the oxidizing species to form a SiO ₂ film having a thickness of about 30 nm on the wafer by ALD. A film forming process was performed. Next, the wafers were not carried out, and post-processing was performed in accordance with the purge at the time of batch replacement. The film formation process and post-treatment were repeated four times. Next, the carbon / nitrogen compound in the SiO ₂ film formed by temperature programmed desorption gas analysis (TDS) was analyzed.
FIG. 10A is a diagram showing a sequence of a comparative example used in this experiment. Here, as a post-treatment, a cycle purge was performed using N ₂ gas as a purge gas. FIG. 10B is a diagram showing the sequence of the example used in this experiment. Here, purging (oxidation purging) using O ₂ plasma was performed as post-processing.
FIGS. 11A, 11B, and 11C are diagrams showing analysis results of carbon / nitrogen compounds in the SiO ₂ film formed by the sequence of FIGS. 10A and 10B. As shown in FIGS. 11A, 11B, and 11C, it was found that carbon / nitrogen compounds are reduced by replacing the cycle purge performed after each film forming process with an O ₂ plasma purge. From this, the amount of amine-based substance in the film deposited on the inner wall of the processing vessel is reduced by performing the oxidation purge process by the O ₂ plasma purge between the previous film formation process and the next film formation process. Was found.

Next, the particles adhering to the wafer are divided into those exceeding 0.2 μm and those occupying most of 0.05 to 0.2 μm, and photographs are taken using a scanning electron microscope (SEM). The composition was analyzed using an energy dispersive X-ray analyzer (EDX). FIG. 12 shows an image of an SEM photograph of particles exceeding 0.2 μm and the analysis results. FIG. 13 shows an image of an SEM photograph of particles of 0.05 to 0.2 μm and analysis results. As shown in these figures, particles having a size exceeding 0.2 μm are shaped like fragments, and Si and O were detected at a peak intensity ratio where Si: O was approximately 1: 2. From this, it is considered that particles having a size exceeding 0.2 μm are caused by peeling of the film formed on the inner wall of the processing container. On the other hand, small particles of 0.2 μm or less were not in the shape of fragments, Si: O was more Si-rich than SiO ₂ , and a small amount of impurities such as C was included. From this, it is considered that particles of 0.2 μm or less are involved in gas phase reaction rather than film peeling.

From the above, the SiO ₂ film deposited on the inner wall of the processing vessel when the film was formed using amino silane as the Si source gas and O ₂ plasma as the oxidizing species contained an amine-based substance, which was released. It is considered that particles having a size of 0.2 μm or less are generated by the gas phase reaction. However, as described above, since the amine itself is a gas component, it does not adhere to the wafer by itself, and it does not become a solid even if it reacts in a mixed state with an oxidizing species, so the amine itself is released. However, no particles are generated. As described above, since particles containing 0.2 μm or less contain Si and also contain C and the like, the amine-based substance involved in the particles is not an amine itself but an unreacted aminosilane. Conceivable.
That is, the film deposited on the inner wall of the processing vessel contains amine, which is a reaction product, and unreacted aminosilane in addition to SiO _{2 as} the main component, and this unreacted aminosilane is contained in the gas phase. When released, it is considered that it reacts with O ₂ plasma, which is an oxidizing species, to become a solid oxide, which becomes fine particles of 0.2 μm or less. Therefore, reducing the release of aminosilane from the film deposited on the inner wall of the processing container 1 during the film forming process is effective in reducing microparticles. Therefore, in this embodiment, an O ₂ plasma purge (oxidation purge) is performed between the preceding film forming process and the next film forming process.

In other words, conventionally, a cycle purge using an inert gas is performed between the film forming process and the film forming process without performing the oxidation purge as in the present embodiment, and the film is deposited on the inner wall of the processing container 1. A lot of aminosilane remains in the SiO ₂ film 60. In this case, as shown in FIG. 14A, a large amount of aminosilane gas is released from the SiO ₂ film 60 on the inner wall of the processing container 1 during the next film forming process. Since this gas is oxidized by O ₂ plasma in the gas phase, a lot of gas phase particles are generated and the number of particles adhering to the wafer W is increased. On the other hand, the amount of aminosilane remaining in the SiO ₂ film 60 is reduced by performing the O ₂ plasma purge (oxidation purge) after the film formation process, compared with the case where the cycle purge is performed. In this case, as shown in FIG. 14B, the amount of aminosilane gas released from the SiO ₂ film 60 on the inner wall of the processing container 1 is reduced during the next film forming process. For this reason, gas phase particles are reduced, and particles adhering to the wafer W can be reduced.

  In this regard, the present embodiment is a technique that is completely different from the above-described Patent Documents 2 and 3 that prevent film peeling by modifying the film deposited on the inner wall of the processing container.

In the present embodiment, the oxidizing gas used in the oxidation purge process can be the same as the oxidizing gas used in the SiO ₂ film forming process. Further, the oxidizing gas used in the oxidation purge process can be supplied in the same manner as the film forming process of the SiO ₂ film (O ₂ plasma is exemplified in this embodiment), and no special equipment is required. .

Such a phenomenon that the Si source gas is contained in the SiO ₂ film deposited on the inner wall of the processing container and is released during the processing occurs even when aminosilane is used as the Si source gas.

In order to confirm the effect of this embodiment, another experiment was conducted. FIG. 15 is a diagram for explaining an experiment for comparing a conventional method and a method according to an embodiment of the present invention. Here, as shown in FIG. 15, the inside of the processing chamber was O ₂ plasma purged (oxidation purge) without depositing a wafer, with the film deposited with a cumulative film thickness sufficient to generate particles on the inner wall of the processing chamber. . Next, the wafer is carried into the processing container, and monovalent aminosilane (DIPAS) is used as the Si source gas, and O ₂ plasma is used as the oxidizing species to form a SiO ₂ film having a thickness of about 30 nm on the wafer by ALD. A film was formed. Then, the particles on the wafer were measured. This sequence was repeated twice. Thereafter, the inside of the processing container was cycle purged with N ₂ gas without carrying in the wafer. Next, a SiO ₂ film having a thickness of about 30 nm was formed on the wafer by ALD in the same manner. Then, the particles on the wafer were measured. This sequence was repeated twice.

FIG. 16 is a diagram showing the number of particles of 0.05 μm or more on the wafer obtained by this experiment. FIG. 17 is a diagram showing the number of particles exceeding 0.2 μm among the particles shown in FIG. FIG. 18 is a diagram showing the number of particles of 0.05 to 0.2 μm among the particles of FIG. As shown in FIG. 16, it was confirmed that the number of particles decreased by performing the O ₂ plasma purge as compared with the case of performing the cycle purge. Further, as shown in FIGS. 17 and 18, the number of particles exceeding 0.2 μm is very small, and the number does not change depending on the presence or absence of the O ₂ plasma purge. However, it was confirmed that the fine particles of 0.05 to 0.2 μm occupy most of the whole, and the number of fine particles was reduced by the O ₂ plasma purge.

Note that the above-described silicon oxide film (SiO ₂ film) film forming process, oxidation purge process, and by-product film cleaning process are all performed at room temperature (20 to 30) by using a specific processing gas and processing conditions. (For example, 25 ° C.). Below, the usage method of the film-forming apparatus for implement | achieving a room temperature sequence is demonstrated.

For this room temperature sequence, in the film forming apparatus 100 of FIG. 1, the oxygen-containing gas supply source 17 is configured to supply O ₂ gas as the oxygen-containing gas. However, as the oxygen-containing gas, CO ₂ gas, NO gas, N ₂ O gas, H ₂ O gas, and O ₃ gas can be used instead. The Si source gas supply source 20 is configured to supply diisopropylaminosilane (DIPAS) gas. The cleaning gas supply source 42 is configured to supply HF gas.

In the film forming process, the film forming process temperature in the processing container 1 is set to room temperature, and ALD is performed by repeating the following cycle while the processing container 1 is exhausted by the vacuum exhaust mechanism VEM. That is, first, an adsorption process is performed in which the DIPAS gas is supplied into the processing container 1 while the O ₂ gas is not supplied into the processing container 1. Thereby, an adsorption layer containing silicon is formed on the surface of the wafer W. Next, a first purge step is performed in which the inert gas is supplied into the processing container 1 while the DIPAS gas and the O ₂ gas are not supplied into the processing container 1 and the processing container 1 is evacuated. Next, an oxidation process is performed in which the O ₂ gas is supplied into the processing container 1 while the DIPAS gas is not supplied into the processing container 1. Thereby, the adsorption layer on the surface of the wafer W is oxidized. Next, a second purge step is performed in which the inert gas is supplied into the processing container 1 while the DIPAS gas and the O ₂ gas are not supplied into the processing container 1 and the inside of the processing container 1 is exhausted.

Here, in the adsorption step, the pressure in the processing container 1 is set to 13.3 to 3990 Pa (0.1 to 30 Torr), preferably 13.3 to 666.5 Pa (0.1 to 5.0 Torr). In the oxidation step, the pressure in the processing container 1 is set to 13.3 to 1333 Pa (0.1 to 10 Torr), preferably 13.3 to 120 Pa (0.1 to 0.93 Torr). The oxidation step is excited by converting the O ₂ gas into plasma by the mechanism 30 in which the pressure of the plasma generation mechanism 30 is less than 400 Pa and the high frequency power applied to the electrode is 50 to 500 W, preferably 10 to 250 W. While being supplied into the processing container 1. The adsorption layer on the surface of the wafer W is oxidized by radicals derived from the generated O ₂ gas.
In the oxidation purge process that is performed after the wafer boat 5 loaded with the film-formed wafer W is unloaded from the processing vessel 1, the oxidation purge processing temperature in the processing vessel 1 is set to room temperature, and the inside of the processing vessel 1 is evacuated by the vacuum exhaust mechanism VEM. The following operation is performed while exhausting.

First, the inside of the processing container 1 is evacuated to about 0.133 to 1333 Pa (0.001 to 10 Torr). Then, while supplying an O ₂ gas into the processing container 1, a step of not supplying DIPAS gas into the processing vessel 1. In this step, the pressure in the processing container 1 is set to 13.3 to 1333 Pa (0.1 to 10 Torr), preferably 13.3 to 120 Pa (0.1 to 0.93 Torr). This step is excited by converting the O ₂ gas into plasma by the mechanism 30 in which the pressure of the plasma generation mechanism 30 is less than 400 Pa and the high frequency power applied to the electrode is 10 to 500 W, preferably 50 to 250 W. While being supplied into the processing container 1. The time for this step is set to 60-3600 sec. Oxidation is performed on the by-product film deposited in the processing container 1 by radicals derived from the generated O ₂ gas.

In the cleaning process performed when the accumulated film thickness of the silicon oxide film (SiO ₂ film) reaches a predetermined value within 2 to 5 μm, the cleaning process temperature in the process container 1 is set to room temperature, and the process container is operated by the vacuum exhaust mechanism VEM. The following operation is performed while evacuating the interior of 1.

First, the inside of the processing container 1 that accommodates the wafer boat 5 on which product wafers are not mounted is evacuated to about 0.133 to 1333 Pa (0.001 to 10 Torr). Next, a process of supplying HF gas into the processing container 1 while not supplying O ₂ gas and DIPAS gas into the processing container 1 is performed. In this step, the pressure in the processing container 1 is set to 13.3 to 101325 Pa (0.1 to 760 Torr), preferably 133 to 13332 Pa (1 to 100 Torr). Thereby, the by-product film deposited in the processing container 1 is removed by etching with HF gas.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, an example is shown in which the present invention is applied to a batch-type film forming apparatus in which a plurality of semiconductor wafers are mounted and film formation is performed collectively. Instead, the present invention can also be applied to a single-wafer type film forming apparatus that forms a film for each wafer.

In the above embodiment, an example was shown in which an aminosilane was used as the Si source gas and an SiO ₂ film was formed by ALD using oxygen-containing plasma such as O ₂ plasma as the oxidizing species. Instead, other Si source gases such as SiH ₄ , SiH ₃ Cl, SiH ₂ Cl ₂ , and SiHCl ₃ can be used in the present invention. The oxidizing species is not limited to oxygen-containing plasma, and other active species such as ozone gas can also be used. Depending on the Si source gas, not only the active species but also an oxygen-containing gas such as O ₂ gas can be used. The film forming method is not limited to ALD but may be CVD. However, since ALD is directed to low-temperature film formation, it is considered that more Si source gas remains in the film. For this reason, the present invention is effective when the SiO ₂ film is formed by ALD.

In the above embodiment, the oxidation purge between the film forming process is performed using an oxygen-containing plasma such as O ₂ plasma. Alternatively, the oxidation purge can be performed using other active species such as ozone gas as in the oxidation step during the film formation process. Also in this case, depending on the Si source gas, not only the active species but also an oxygen-containing gas itself such as O ₂ gas can be used.

  Furthermore, the object to be processed is not limited to a semiconductor wafer, and the present invention can be applied to other substrates such as an LCD glass substrate.

1; processing vessel 5; wafer boat 14; oxygen-containing gas supply mechanism 15; Si source gas supply mechanism 16; purge gas supply mechanism 19; gas dispersion nozzle 22; gas dispersion nozzle 30; plasma generation mechanism 33; 40; heating mechanism 100; film forming apparatus 201; film forming process 202; oxidation purge process W; semiconductor wafer (object to be processed)

Claims (11)

A diisopropylaminosilane (DIPAS) gas is supplied as a Si source gas in the processing vessel, an oxygen-containing gas plasma is supplied as an oxidizing species, and room temperature is used as a processing temperature. A film forming method for performing a film forming process for forming a SiO ₂ film,
Between the preceding film forming process and the next film forming process,
In a state where the object to be processed is unloaded from the processing container, the oxygen-containing gas plasma is supplied without supplying the DIPAS gas into the processing container while exhausting the processing container, and the processing temperature is set to room temperature. A film-forming method characterized by performing an oxidation purge process for performing oxidation for reducing the amount of aminosilane remaining in a by-product deposited in the processing vessel . In the method, after the cumulative film thickness of the SiO ₂ film formed by the film formation process reaches a predetermined value within 2 to 5 μm, the film is deposited in the processing container before performing the film formation process next. A cleaning process for removing the by-product film, wherein the cleaning process is performed by supplying a fluorine-containing gas into the processing container while evacuating the processing container. The film forming method according to claim 1, wherein etching is performed.   The film forming method according to claim 2, wherein the cleaning process uses room temperature as a processing temperature in the processing container and supplies HF gas as the fluorine-containing gas.   The film forming process includes a step of supplying the DIPAS gas into the processing container and a step of supplying the oxygen-containing gas into the processing container, and a step of removing the gas remaining in the processing container. The film forming method according to any one of claims 1 to 3, wherein the film forming method is alternately performed with a sandwich. 5. The oxygen-containing gas according to claim 1, wherein the oxygen-containing gas is at least one selected from O ₂ gas, CO ₂ gas, NO gas, N ₂ O gas, and H ₂ O gas. The film forming method according to one item. The step of supplying the DIPAS gas in the film forming process sets the pressure in the processing vessel to 13.3 to 3990 Pa, and the step of supplying plasma of the oxygen-containing gas includes O ₂ gas as the oxygen-containing gas. The film forming method according to any one of claims 1 to 4, wherein the pressure in the processing container is set to 13.3 to 1333 Pa.   The film forming method according to claim 6, wherein in the step of supplying the oxygen-containing gas plasma in the oxidation purge process, the pressure in the processing container is set to 13.3 to 1333 Pa.   The processing container is configured to accommodate a holding member that holds a plurality of objects to be processed in multiple stages, and the oxidation purge process is performed by placing a batch of objects to be processed next on the holding member. The film forming method according to claim 1, wherein the preparation operation is performed in parallel with performing the operation outside the processing container. A film forming apparatus,
A vertical processing container capable of holding a vacuum;
A holding member for holding a plurality of objects to be processed in a multistage manner in the processing container;
A loading / unloading mechanism for loading / unloading the holding member with respect to the processing container;
A source gas supply mechanism for supplying diisopropylaminosilane (DIPAS) gas as Si source gas into the processing vessel;
An oxygen-containing gas supply mechanism for supplying an oxygen-containing gas into the processing vessel;
A plasma generation mechanism for converting the oxygen-containing gas attached to the processing vessel into plasma;
An exhaust system for exhausting the inside of the processing vessel;
A control mechanism for controlling the operation of the device;
And the control mechanism includes:
9. A film forming apparatus, wherein the apparatus operation is controlled so that the film forming method according to claim 1 is executed. A method of using a film forming apparatus,
The film forming apparatus includes:
A vertical processing container capable of holding a vacuum;
A holding member for holding a plurality of objects to be processed in a multistage manner in the processing container;
A source gas supply system for supplying diisopropylaminosilane (DIPAS) gas as Si source gas into the processing vessel;
An oxygen-containing gas supply system for supplying an oxygen-containing gas into the processing vessel;
A plasma generation mechanism for converting the oxygen-containing gas attached to the processing vessel into plasma;
An exhaust system for exhausting the inside of the processing vessel;
Comprising
The film forming process by the film forming apparatus includes:
Use room temperature as the film forming temperature in the processing vessel,
Supplying the DIPAS gas from the source gas supply system into the processing container while exhausting the processing container by the exhaust system;
Supplying the oxygen-containing gas from the oxygen-containing gas supply system into the processing container while exhausting the inside of the processing container by the exhaust system; and while the oxygen-containing gas is converted into plasma by the plasma generation mechanism Supplying and oxidizing the substance derived from the DIPAS gas with radicals derived from the oxygen-containing gas generated thereby to form the silicon oxide film;
Comprising
Between the preceding film forming process and the next film forming process,
In a state where the object to be processed is unloaded from the processing container, the oxygen-containing gas plasma is supplied without supplying the DIPAS gas into the processing container while exhausting the processing container, and the processing temperature is set to room temperature. A method of using a film forming apparatus, comprising: performing an oxidation purge process for performing oxidation to reduce the amount of aminosilane remaining in a byproduct deposited in the processing container .   In the method, after the accumulated film thickness of the silicon oxide film formed by the film forming process reaches a predetermined value within 2 to 5 μm, it is deposited in the processing container before performing the film forming process next. A cleaning process is further performed to remove the by-product film, and the cleaning process uses room temperature as the processing temperature in the processing container, and HF is put into the processing container while exhausting the processing container. The method for using a film forming apparatus according to claim 10, wherein a gas is supplied to etch the by-product film.