JP2009212303A - Substrate processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the improvement of yield, the improvement of through-put, and the reduction of a manufacturing cost by raising loading effect, step coverage, and surface flatness in forming the thin film of a metal oxide, and shortening a depositing time. <P>SOLUTION: The substrate processing method includes: a first step for bringing a substrate into a processing chamber; a second step for supplying the first raw material being a metallic compound or silicon compound to the processing chamber; a third step for exhausting the atmosphere of the processing chamber; a fourth step for introducing the second raw material being O-containing gas to the processing chamber; a fifth step for exhausting the atmosphere of the processing chamber; a sixth step for exposing the surface of the substrate with H<SB>2</SB>O; a seventh step for exhausting the atmosphere of the processing chamber; and an eighth step for bringing the substrate out of the processing chamber. The second to seventh steps are sequentially repeated prescribed times, so as to form a metal oxide film or a silicon oxide film on the surface of the substrate. The sixth step is performed, while heating the substrate within the range of temperature by 155°C to 165°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate processing method for forming an oxide film on a substrate such as a silicon wafer by using an ALD (Atomic Layer Deposition) film forming method, and particularly to forming an ultra-low temperature oxide film to be processed at 100 ° C. to 300 ° C. The present invention relates to a substrate processing method to be performed.

  In recent years, with the increase in density and multilayer wiring of semiconductor DRAM devices, film formation at a low temperature is required, and further, surface flatness and step coverage (recess embedding property) are required. The ALD method has attracted attention as a film forming method with excellent coverage.

In the ALD method, a metal-containing source gas A and an oxidizing source gas B (for example, O ₃ , O ₂ , H ₂ O, etc.) are alternately supplied onto a substrate set at a relatively low temperature. In this method, a thin film is deposited on a substrate through a process such as adsorption and desorption of a source gas.

However, as a problem in forming oxide films by alternately flowing these source gases into the reaction chamber, if a patterned wafer with a trench (groove) structure is used, the film thickness decreases at the center of the wafer, resulting in a step difference. There is a problem that the coverage is poor, or the coverage of an oxide film such as an HfO ₂ film or an SiO ₂ film is lowered (hereinafter referred to as a loading effect) depending on the number of pattern wafers loaded in one batch.

  Increasing the supply amount of oxide film raw material to improve the step coverage and loading effect or increasing the supply time will improve the step coverage and loading effect, but will increase the deposition time and increase throughput. The cost of the raw material is increased due to the deterioration of the raw material consumption and the COO (Cost of Ownership: manufacturing cost per sheet) is deteriorated.

JP 2001-152339 A

  In view of such circumstances, the present invention improves the loading effect, step coverage, and surface flatness in metal oxide thin film formation, shortens the film formation time, improves yield, improves throughput, The manufacturing cost is reduced.

The present invention provides a first step of carrying a substrate into a processing chamber, a second step of supplying a first raw material that is a metal compound or a silicon compound to the processing chamber, and a first step of exhausting the atmosphere of the processing chamber. 3, a fourth step of introducing a second raw material that is an O-containing gas into the processing chamber, a fifth step of exhausting the atmosphere of the processing chamber, and H ₂ O on the surface of the substrate. Including a sixth step of exposing, a seventh step of evacuating the atmosphere of the processing chamber, and an eighth step of unloading the substrate from the processing chamber, and the second step to the seventh step. A substrate processing method of repeatedly performing a predetermined number of times in order to form a metal oxide film or a silicon oxide film on the surface of the substrate, wherein the substrate is heated in a temperature range of 155 ° C. to 165 ° C. The present invention relates to a substrate processing method for performing step 6.

According to the present invention, the metal oxide film or silicon oxide film is a substrate treatment selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , RuO ₂ , IrO ₂ , SiO _2, etc. According to the method, the metal oxide thin film or the silicon oxide film is any one of Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , RuO ₂ , IrO ₂ , and SiO _2. The first raw material is an organic compound containing any one of an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, and a silicon atom as a metal compound, or The present invention relates to a substrate processing method which is any chloride.

The present invention also relates to the substrate processing method, wherein the first raw material that is the organic compound is MH _n [OCR ¹ R ² R ³ ] _mn , MH _n [NR ⁴ R ⁵ ] _mn .

M represents a metal containing any one of an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, and a silicon atom, m represents a stable valence of the metal, and n represents 0. An integer of ˜2, but when M is an atom other than silicon, 0 is represented, and R ^1-5 is an alkyl group which may contain an ether bond in the middle of 1 to 4 carbon atoms.

The present invention also relates to a substrate processing method wherein the second raw material is any one of ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), and oxygen (O ₂ ), and the third step The fifth step and the seventh step relate to a substrate processing method including supplying an inert gas of helium (He), neon (Ne), argon (Ar), or nitrogen (N ₂ ). Furthermore, the sixth step relates to a substrate processing method for introducing H ₂ O into the processing chamber.

According to the present invention, a first step of carrying a substrate into a processing chamber, a second step of supplying a first raw material that is a metal compound or a silicon compound to the processing chamber, and exhausting the atmosphere of the processing chamber. A third step of introducing a second raw material, which is an O-containing gas, into the processing chamber, a fifth step of exhausting the atmosphere of the processing chamber, and H _{2 on} the surface of the substrate. Including a sixth step of exposing O, a seventh step of evacuating the atmosphere of the processing chamber, and an eighth step of unloading the substrate from the processing chamber, from the second step to the seventh step It is a substrate processing method in which a process is repeatedly performed a predetermined number of times in order to form a metal oxide film or a silicon oxide film on the surface of the substrate, while heating the substrate in a temperature range of 155 ° C. to 165 ° C., Since the sixth step is performed, the substrate surface is terminated with OH, and the oxide film Improves material adsorbability, improves loading effect, step coverage, and surface flatness, shortens film formation time, improves yield, improves throughput, and reduces manufacturing costs. To do.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

Atomic Layer Deposition (ALD) was discovered in the 1960s-1970s by a group of Russian Alessovskii, Finnish Suntola, etc. as a self-limited gas-solid reaction. However, the process is not yet fully understood. Recently, several deposition models for ALD HfO ₂ have also been reported.

An example of film formation by the ALD method using a system of HfCl ₄ and H ₂ O as a raw material is described in R.A. L. Puruunen, M .; A. Alam, M .; L. Green, M.M. According to their report, Ylilammi et al. Reported that the ALD initial film formation process is divided into three regions according to the relationship between the number of cycles and the film thickness. It is supposed to exist. The relationship between the number of cycles and the film thickness in these regions differs depending on whether the adsorption surface is hydrogen-terminated or OH-terminated. These were recognized because the adsorption was different between the chemical oxide surface and the hydrogen-terminated surface treated with HF.

Also, MA Alam and M.A. L. Green expressed the deposition rate of HfO _{2 in} the reaction system of HfCl ₄ and H ₂ O by the following equations (1) and (2).

dN _HfO / dC = K _COV N _OH (Formula 1)

dN _OH / dC = k ₂ (N ₀ −N _SiOH ) + (α _cov −1) K _COV N _OH (Formula 2)

Here, N _HfO is the total amount of HfO ₂ film deposited per unit area after the ALD reaction, C is the number of ALD cycles, K _COV is the number of hydroxyl groups (—OH) that react with HfCl _4, and N _OH is the hydroxyl group The surface concentration of K ₂ represents the rate constant of the hydroxyl group that newly binds to Si.

In addition, R.M. L. Puurunen the beginning of First Half-reaction Cl group HfCl ₄ reacts with OH groups on the substrate with HfCl _x is adsorbed, Cl of HfCl _x in Second Half-Reaction has proposed a model to replace the OH . Thus, it is considered that the adsorption reaction proceeds due to the presence of OH groups on the substrate.

  The surface of Si etched with 1% HF has been found to be a chemically stable surface with most of dangling bonds terminated by H (hydrogen) by XPS studies such as Chabal et al. From AT & T.

However, organic materials such as Hf (NMeEt) ₄ and Si (NMeEt) ₃ are difficult to adsorb on the non-polar H-terminated substrate surface. On the other hand, when the OH is terminated, the substrate surface has polarity and is easily adsorbed.

  Therefore, in the present invention, an OH-terminated surface is formed, and the adsorptivity is improved in the film forming process using the organic material.

Here, as an example of a reaction system that can form an OH-terminated surface, hydrolysis of Si—N bonds, oxidation and hydrolysis of Si—H bonds, or Si—O—Si bonds as shown in FIG. Examples include hydrolysis and reductive cleavage. Among these, the method of allowing H ₂ O to act is simple and effective.

  Next, a specific method for forming an OH-terminated surface will be described. The experimental method and experimental results up to the present invention will be described.

  FIG. 2 shows a multiple reflection IR spectroscopic analyzer (hereinafter referred to as MIR-IRAS measuring apparatus) 1 used in the experiment, and the measurement is performed using the MIR-IRAS measuring apparatus 1. -Performed by IRAS measurement method.

  The feature of the MIR-IRAS measurement method is high resolution and surface sensitivity. In normal transmission infrared light absorption measurement, the absorption of infrared light is only twice on the front and back surfaces, but in the MIR-IRAS measurement method, in the case of the 50 mm long multiple internal reflection prism 2, the number of internal reflections is approximately 100 times. The surface detection sensitivity can be greatly increased by the number of times of sampling that is about two digits larger.

  The multiple internal reflection prism (hereinafter referred to as Si prism) 2 is an n-type P-doped Si (100), a 10 Ω-cm substrate cut out to 0.5 × 10 mm × 40 mm, and an infrared light incident surface and a detection surface 45. It is made by polishing at °. The Si prism 2 was washed with dilute HF and RCA cleaned to prepare a sample.

  Next, this prism is installed in the MIR-IRAS measuring apparatus 1.

The chamber 3 of the MIR-IRAS measuring apparatus 1 has an ultra high vacuum (UHV) and a base pressure of about 1 × 10 ⁻¹⁰ Torr. The internal pressure of the chamber 3 was measured using an ion gauge, and the surface temperature was measured with a radiation thermometer (pyromerin).

MCT infrared detector (InSb) in which excited infrared light is introduced into the Si prism 2 sample through the CaF ₂ window 4, is reflected in the Si prism 2 and is cooled with liquid nitrogen through the CaF ₂ window 5. 6 is condensed. The detected infrared light is plotted using measurement and analysis software to analyze the absorption peak position of the raw material.

  FIG. 3 shows data obtained by the MIR-IRAS measuring apparatus 1.

The temperature of the Si prism 2 oxidized at 1050 ° C. was raised from 100 ° C. to 200 ° C. at intervals of 10 ° C., and the behavior of an OH absorption peak of 3750 cm ⁻¹ when H ₂ O was irradiated was confirmed.

Under the conditions of 100 ° C. to 150 ° C. and 170 ° C. to 200 ° C., all of the OH peaks decrease (adsorption amount is small), but the conditions of 155 ° C. and 160 ° C., particularly the increase of the OH peak at 160 ° C. A large amount). From this, it was found that OH increased specifically at 155 ° C., 160 ° C., particularly 160 ° C. on the oxide film surface. It has been confirmed that this tendency is the same on the Si surface. Accordingly, the substrate temperature is preferably in the vicinity of 160 ° C., for example, 155 ° C. to 165 ° C. in order to terminate the OH by irradiation with H ₂ O.

  4A and 4B are diagrams from the lower side, respectively. In FIG. 4, the diagram A shows the result of adsorbing TDMAS on the Si surface after HF cleaning, and the diagram B shows the room temperature on the surface of the oxide film wet-oxidized at 1050 ° C. As a result of adsorbing TDMAS, the line C shows the result of adsorbing TDMAS after forming OH at 160 ° C. on the surface wet-oxidized at 1050 ° C.

  The horizontal axis of the graph represents the wave number and the vertical axis represents the absorption rate, but the vertical axis position is adjusted so that the graphs do not overlap.

In the diagram A, the Si surface after HF cleaning is mostly H-terminated, but is considered to be partially OH-terminated due to the influence of residual moisture and the like. A CH absorption peak is observed in the vicinity of 2800 to 3000 cm ⁻¹ , which indicates absorption due to the CH stretching vibration of TDMAS. It can be seen that absorption due to CH stretching vibration is observed with a small peak on the Si substrate surface after the HF cleaning, and that TDMAS is adsorbed.

On the other hand, in the diagram B, on the surface oxidized by wet oxidation at 1050 ° C., absorption due to CH stretching vibration is not observed, and TDMAS is not adsorbed. This is considered to be because there is no OH termination on the SiO ₂ surface due to the formation of Si—O—Si bonds. Therefore, TDMAS does not adsorb on the wet oxidized surface at 1050 ° C.

As shown in the diagram C, when TDMAS is adsorbed on the surface of the Si substrate supplied with H ₂ O at 160 ° C. by supplying H ₂ O at 160 ° C. and wet-oxidized at 1050 ° C., the CH stretch of 2800 to 3000 cm ⁻¹ . Vibration increases. In addition, the OH absorption peak at 3750 cm ⁻¹ decreases. From this, it became clear that the formation of OH is effective in increasing the adsorption of TDMAS.

Line C in FIG. 4 shows MIR-IRAS data when TDMAS is adsorbed on the surface of the substrate on which OH is formed by irradiation with H ₂ O. The case where a metal oxide film is formed only with ozone and ozone oxide, CH ₂ (2960cm ^-1) in 2800-3000Cm ^-1 when continuously performed of H ₂ O oxidation, CH ₃ (2869cm ^-1), the absorption of _{N (CH 3) 2 (2800cm} -1) A comparison of the integrated values of the peaks is shown in FIG. In any of the comparisons, it was found that the amount of adsorption of TDMAS was increased by about 30% when ozone and H ₂ O were continuously treated as compared with the case of oxidizing with ozone alone. Further, it was found that TEMAH (Tetrakis (ethylmethylamino) hafnium) other than TDMAS increases the amount of TEMAH adsorbed by treatment with ozone and H ₂ O as in TDMAS.

In addition, the supply amount of each raw material is as follows. In the case where the metal oxide film was formed only by ozone using TDMAS, 2000 L of TDMAS was supplied, 2.4 × 10 ⁷ L of ozone was supplied, and 2000 L of TDMAS was further supplied. When TDMAS is continuously subjected to ozone oxidation and H ₂ O oxidation, 2000 L of TDMAS is supplied, then 2.4 × 10 ⁷ L of ozone is supplied, and then 6.8 × 10 ^{7 of} H ₂ O is supplied. Further, 2000 L of TDMAS was supplied. When a metal oxide film was formed using only TOMAH using TEMAH, 3000 L of TEMAH was supplied, 2.4 × 10 ⁷ L of ozone was supplied, and 3000 L of TEMAH was supplied. When TEMAH is continuously subjected to ozone oxidation and H ₂ O oxidation, 3000 L of TEMAH is supplied, then 2.4 × 10 ⁷ L of ozone is supplied, and then H ₂ O is 6.8 × 10 ⁷ L. Then, 3000 L of TEMAH was supplied.

FIG. 6 shows an infrared absorption spectrum when the surface of the ozone-oxidized surface is irradiated with H ₂ O at the time of forming the SiO film, and FIG. 7 shows that the surface of the ozone-oxidized surface is irradiated with H ₂ at 160 ° C. at the time of forming the SiO film. An infrared absorption spectrum when O is irradiated is shown. Comparing FIG. 6 and FIG. 7, in FIG. 6, the adsorption amount of the second layer is 1/10 or less compared to the TDMAS adsorption amount of the first layer, whereas in FIG. 7, the same TDMAS as that of the first layer is obtained. Adsorption can be confirmed.

Further, FIG. 8 shows an infrared absorption spectrum when H ₂ O is irradiated on the ozone oxidation surface at room temperature during HfO formation, and FIG. 9 shows H absorption at 160 ° C. on the ozone oxidation surface during SiO film formation. An infrared absorption spectrum when irradiated with ₂ O is shown. Comparing FIG. 8 and FIG. 9, in FIG. 8, the adsorption amount of the second layer is 1/10 or less compared to the TEMAH adsorption amount of the first layer, whereas in FIG. 9, the same TEMAH as the first layer is obtained. Adsorption can be confirmed.

Let us consider a film formation model for the adsorption of TDMAS (Tridimethylsilane: SiH [N (CH ₃ ) ₂ ] ₃ ) described above on Si and the formation of a silicon oxide film.

FIG. 10 shows a film formation model in the case of using TDMAS as the first raw material and ozone (O ₃ ) and the third raw material H ₂ O as the second raw material (oxidizing raw material).

In addition to the TDMAS as the first raw material, an organic compound containing any one of an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, and a silicon atom as the metal compound or the atom Any of the chlorides may be used. Further, hydrogen peroxide (H ₂ O ₂ ) or oxygen (O ₂ ) may be used as the second raw material (oxidizing raw material).

  (Step 1) The Si substrate surface of the start substrate is terminated with Si—OH or Si—H.

(Step 2) In the TDMAS supply step, TDMAS is adsorbed to the Si—OH site and N (Me) ₂ is desorbed (Me represents a methyl group CH ₃ ).

The substrate temperature in the TDMAS supply step is the same as the substrate temperature (160 ° C.) at the time of H ₂ O supply in step 4 described later. The self-decomposition temperature of TDMAS is 520 ° C., and TDMAS is highly reactive, so that it reacts well even at 160 ° C., and the temperature change is achieved by making the TDMAS supply process and the H ₂ O supply the same temperature. The time required can be omitted and the throughput can be improved.

Further, when the substrate processing is performed by a single wafer method and the substrate is directly heated via the substrate mounting table, the temperature control of the substrate is easy, and the TDMAS (raw material) supply process and H ₂ O (oxidant) are performed. You may change temperature in a supply process.

(Step 3) supplying O ₃ is O-containing raw material, exposing the substrate with an oxygen atom. N (Me) ₂ of the TDMAS molecule adsorbed on the substrate is desorbed in the O ₃ supply step to form a Si—O site, and a part forms Si—O—Si. Further, part of the Si—Si bond of the substrate also forms Si—O—Si.

The O-containing raw material includes N ₂ O, NO, NO _{2 and the} like. However, since N ₂ O, NO, NO _{2 and the} like do not react at extremely low temperatures (155 ° C. to 165 ° C.), those previously activated by remote plasma or the like are supplied.

(Step 4) A reaction reagent containing OH, that is, H ₂ O is supplied at 160 ° C. to form an OH-terminated surface, and the surface of the Si substrate is exposed to H ₂ O. When H ₂ O is supplied, the unreacted N (Me) _{2 from} the adsorbed TDMAS molecule is formed, OH is formed, and a part of the Si—H bond is converted to Si—OH.

The supply of H ₂ O at 160 ° C. results in an increase in the TDMAS adsorption point due to an increase in OH. Incidentally, H as the ₂ O aspect of supply may supply H ₂ O directly, or may be supplied by activating the H or O of H ₂ O by the remote plasma or the like.

Further, as described above, it can be seen that the temperature of the Si substrate when H ₂ O is supplied has an influence on termination with OH, and the heating temperature of the Si substrate is 100 ° C. to 300 ° C., preferably 130 to 180 ° C, more preferably 155 to 165 ° C.

  Further, the process of forming an oxide film on the wafer surface by the ALD method will be described by taking TDMAS as an example.

  FIG. 11 shows a processing sequence in a preferred embodiment of the present invention.

  (Step 01) In the first step, the Si substrate is carried into the processing chamber.

  STEP: 02 In the second step, first, the atmosphere in the processing chamber is evacuated and evacuated, and then TDMAS, which is a metal organic compound raw material, is flowed and adsorbed on the surface of the Si substrate.

(Step 03) In the third step, purging with an inert gas is performed, and the residual Si raw material in the processing chamber is discharged out of the processing chamber. As the inert gas, helium (He), neon (Ne), argon (Ar), nitrogen (N ₂ ) or the like is used.

(Step 04) Ozone (O ₃ ), which is the second source gas (oxidation source), is flowed in the fourth step to remove the dimethylamine N (Me) ₂ group of the first source gas TDMAS adsorbed on the Si substrate surface. Let go.

  (Step 05) In the fifth step, the processing chamber is purged with an inert gas.

STEP: 06 In the sixth step, H ₂ O (reaction reagent as a third raw material) is supplied to the processing chamber at 160 ° C., and the surface of the Si substrate is exposed to H ₂ O. N (CH ₃ ) ₂ is desorbed by supplying H ₂ O, and the surface of the Si substrate is replaced with Si—OH.

  STEP: 07 The process chamber is purged with an inert gas in the seventh step.

As an example, each step time is 1 to 30 seconds for STEP 02 (Si raw material supply process), 5 to 15 seconds for STEP 03 (purging process), and 5 for STEP 04 (O ₃ supply process). 60 seconds, the sTEP: 05 (purge process) is 5 to 15 seconds, the sTEP: 06 (H ₂ O supply step) from 5 to 60 seconds, the sTEP: 07 (purge process) is 5 to 15 seconds .

  12 and 13 show an example of a semiconductor manufacturing apparatus that performs the substrate processing method according to the present invention.

  In the semiconductor manufacturing apparatus 10, a cassette 12 is used as a wafer carrier for storing a substrate (hereinafter referred to as a wafer) 11 made of silicon or the like.

  The semiconductor manufacturing apparatus 10 includes a housing 13, and a maintenance door 14 that can be opened and closed is provided below the front surface of the housing 13. The maintenance door 14 has a cassette loading / unloading port 15 that is opened and closed by a front shutter (not shown). A cassette stage 16 is installed inside the casing 13 of the cassette loading / unloading port 15, and the cassette 12 is loaded onto the cassette stage 16 by an in-process transfer device (not shown). It comes to be carried out from.

  On the cassette stage 16, the cassette 12 is placed by the in-process transfer device so that the wafer 11 in the cassette 12 is in a vertical posture and the wafer inlet / outlet of the cassette 12 faces upward. The cassette stage 16 rotates the cassette 12 clockwise 90 ° to the rear of the housing 13 so that the wafer 11 in the cassette 12 is in a horizontal posture, and the wafer inlet / outlet of the cassette 12 passes behind the housing 13. It is configured to be operable so as to face.

  A cassette shelf 17 is installed in a substantially central portion of the casing 13 in the front-rear direction, and the cassette shelf 17 is configured to store a plurality of cassettes 12 in a plurality of stages and a plurality of rows. The cassette shelf 17 is provided with a transfer shelf 19 in which a cassette 12 to be transferred by a wafer transfer mechanism 18 (described later) is stored. Further, a spare cassette shelf 21 is provided above the cassette stage 16 so as to store the cassette 12 in a preliminary manner.

  A cassette carrying device 22 is installed between the cassette stage 16 and the cassette shelf 17. The cassette carrying device 22 is configured to hold the cassette 12 and can be moved up and down, moved back and forth, and rotated, and is configured to carry the cassette 12 between the cassette stage 16, the cassette shelf 17, and the spare cassette shelf 21. Has been.

  The wafer transfer mechanism 18 is installed behind the cassette shelf 17, and the wafer transfer mechanism 18 holds a required number of wafers 11 (for example, five), rotates in the horizontal direction, and advances and retreats in a horizontal plane. The wafer 11 can be moved up and down, and the wafer 11 is loaded and unloaded from the boat (substrate holder) 23.

  A processing furnace 24 is provided above the rear portion of the housing 13. The lower end portion of the processing furnace 24 is configured to be opened and closed by a furnace port shutter (furnace port opening / closing mechanism) 25.

  Below the processing furnace 24, a boat elevator 26 is provided as an elevating mechanism for loading and unloading the boat 23 into and from the processing furnace 24, and an arm 27 extending from the boat elevator 26 has a lid. The seal cap 28 is horizontally installed, and the seal cap 28 is configured to support the boat 23 vertically and to close the lower end portion of the processing furnace 24.

  The boat 23 includes a plurality of holding members, and each of the plurality of (for example, about 50 to 150) wafers 11 is horizontally held in a state where the wafers 11 are aligned in the vertical direction with their centers aligned. It is configured.

  As shown in FIG. 13, above the cassette shelf 17, a clean unit 29 including a supply fan and a dustproof filter is provided above the cassette shelf 17 so as to supply clean air that is a cleaned atmosphere. In addition, it is provided on the side wall of the housing 13 and is configured to circulate clean air inside the housing 13.

  Next, the operation of the semiconductor manufacturing apparatus 10 described above will be described.

  After the cassette 12 is supplied to the cassette stage 16 and further transferred by the cassette transfer device 22 to the specified shelf position of the cassette shelf 17 or the spare cassette shelf 21, it is delivered and temporarily stored. It is transferred from the cassette shelf 17 or the preliminary cassette shelf 21 to the transfer shelf 19 or directly transferred to the transfer shelf 19.

  When the cassette 12 is transferred to the transfer shelf 19, a predetermined number of wafers 11 are loaded into the boat 23 in the lowered state by the wafer transfer mechanism 18.

  When a predetermined number of wafers 11 are loaded into the boat 23, the lower end of the processing furnace 24 is opened by the furnace port shutter 25. Subsequently, the boat 23 holding the group of wafers 11 is loaded into the processing furnace 24 when the seal cap 28 is raised by the boat elevator 26.

  Arbitrary processing is performed on the wafer 11 in the processing furnace 24, and after the processing, the wafer 11 and the cassette 12 are discharged to the outside of the housing 13 in the reverse procedure described above.

  Next, the processing furnace 24 applied to the substrate processing apparatus described above will be described with reference to FIGS.

  A reaction tube 32 as a reaction vessel for processing the wafer 11 is provided inside a heater 31 that is a heating device (heating means), and a manifold 33 made of stainless steel or the like is provided at the lower end of the reaction tube 32 in an airtight manner. The lower end opening of the manifold 33 forms a furnace port. The furnace port is hermetically closed by a seal cap 28 which is a lid. At least the reaction chamber 32 is defined by the reaction tube 32, the manifold 33, and the seal cap 28.

  The boat 23, which is a substrate holding member (substrate holding means), is erected on the seal cap 28 via a boat support base 35.

  A plurality of types of gas supply pipes (first gas supply pipe 36a, second gas supply pipe 36b, and third gas supply pipe 36c) as supply paths for supplying a processing gas are provided in the processing chamber 34. It has been. The first gas supply pipe 36a, the second gas supply pipe 36b, and the third gas supply pipe 36c are provided in order from the upstream direction, mass flow controllers 37a, 37b, 37c, which are flow rate control devices, and valves 38a, 38b, 38c, which are on-off valves. The carrier gas supply pipes 39a and 39b for supplying the carrier gas are joined together.

  The carrier gas supply pipes 39a and 39b are provided with mass flow controllers 37e and 37d as flow rate control devices and valves 38e and 38d as opening / closing valves in order from the upstream direction.

  A first nozzle 41 and a second nozzle 42 are provided in the circumferential direction along the inner wall of the reaction tube 32, and a first gas supply hole 43 for supplying a gas is provided on a side surface of the first nozzle 41. A second gas supply hole 44 for supplying gas is provided on the side surface of the second nozzle 42.

  The first gas supply hole 43 and the second gas supply hole 44 have the same opening area from the lower part to the upper part, and are provided at the same opening pitch.

The gas flowing through the first gas supply pipe 36a, the second gas supply pipe 36b, and the third gas supply pipe 36c is an oxide film material (for example, Si organic material such as TDMAS) from the first gas supply pipe 36a, respectively. The second gas supply pipe 36b is ozone gas which is an oxidizing gas, and the third gas supply pipe 36c is H ₂ O which is an oxidizing gas. The first gas supply pipe 36a, the second gas supply pipe 36b, and the third gas supply pipe 36c purge the carrier gas supply pipes 39a and 39b with N ₂ purge gas.

  The processing chamber 34 is connected to a vacuum pump 53 which is an exhaust device (exhaust means) through a valve 52 by a gas exhaust pipe 51 for exhausting gas, and is evacuated. The valve 52 is an open / close valve capable of opening / closing the valve to stop evacuation / evacuation of the processing chamber and further adjusting the pressure by adjusting the valve opening.

  The boat 23 charged in the processing chamber 34 is rotated by driving a boat rotating mechanism 54, and the rotation of the boat 23 improves the uniformity of substrate processing. .

  The controller 55 as a control unit includes the mass flow controllers 37a, 37b, 37c, 37d, 37e, the valves 38a, 38b, 38c, 38d, 38e, the valve 52, the heater 31, the vacuum pump 53, the boat. It is connected to a rotating mechanism 54 and a boat raising / lowering mechanism (not shown). The flow rate adjustment of the mass flow controller, the opening / closing operation of the valve, the pressure adjustment operation, the temperature adjustment of the heater 31, the start / stop of the vacuum pump 53, Adjustment of the rotation speed of the boat rotation mechanism 54, control of the raising / lowering operation of the wafer transfer mechanism 18, the boat elevator 26, and the like are performed.

  Next, an example of a film forming process in this embodiment will be described.

Note that an oxide film material used in the ALD film forming method preferably has an appropriate chemical stability and high reactivity, and the organic compound is a tertiary alkoxide or secondary alkoxide (MH _n [OCR ¹ R ² R ³ _mn , MH _n [NR ⁴ R ⁵ ] _mn : M represents an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, or a silicon-containing metal including m, Stability valence of metal, n is an integer of 0 to 2; however, when M is an atom other than silicon, 0 is represented, and R ^1-5 is an alkyl having an ether bond in the middle of 1 to 4 carbon atoms. And a group having as a ligand. For example, as a hafnium raw material, Hf (OtBu) ₄ (Hafnium tertiary butoxide: Hf [OC (CH ₃ ) ₃ ] ₄ ), Hf (MMP) ₄ (Tetrakis 1-methyl 2-methyl hafniumC (f: _{CH 3) 2 CH 2 OCH 3} ] 4), TDEAHf (Tetrakis diethyl amino hafnium: Hf [N (C 2 H 5) 2] 4), TEMAH (Tetrakis ethylmethyl amino hafnium: Hf [N (CH 3) (C 2 H _{5)] 4)} and the like, chlorides material ₄ such as organic materials and HfCl of Hf is used.

In addition, for example, in the case of silicon, hydrogen is also a preferable ligand in addition to the above ligands, up to two. As the oxidizing material, ozone (O ₃ ), plasma-excited oxygen, or the like is used.

Further, even when an SiO ₂ film is formed by ALD film formation as in the case of the HfO ₂ film, Si (MMP) ₄ (Tetrakis 1-methyl 2-methyl 2-propoxy silicon: Si [OC (CH ₃ )) ₂ CH ₂ OCH ₃ ] ₄ ) and TDMAS (Tris ethylamino silicon: SiH [N (CH ₃ ) ₂ ] ₃ ) and other organic materials such as SiCl ₄ and chloride materials such as SiCl ₄ are used.

When a silicon oxide film such as SiO ₂ or a metal oxide film such as HfO ₂ is formed, the material used for SiO ₂ is TDMAS (tridimethylaminosilicon, SiH (NMe ₂ ) ₃ ), HfO ₂ . As amino materials such as TEMAH (tetrakismethylethylaminohafnium, Hf (NEtMe) ₄ ) and TDEAH (tetrakisdiethylaminohafnium, Hf (NEt ₂ ) ₄ ) are used.

Me represents a methyl group (CH ₃ ), and Et represents an ethyl group (C ₂ H ₅ ).

  Further, an organic compound containing an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, or a silicon atom as a metal compound, or a raw material selected from chlorides of the above atoms can be used.

Hereinafter, a film forming process example using the ALD method will be described based on an example in which a SiO ₂ film is formed using TDMAS, ozone, and atomic hydrogen, which is one of semiconductor device manufacturing processes.

  In the ALD (Atomic Layer Deposition) method, reactive gases as a plurality of types of raw materials used for film formation are alternately supplied onto the wafer 11 one by one under a certain film formation condition (temperature, time, etc.). In this method, the film is adsorbed on the wafer 11 in atomic units, and film formation is performed using a surface reaction. At this time, the film thickness is controlled by the number of cycles in which the reactive gas is supplied (for example, if the film forming speed is 1 kg / cycle, 20 cycles are performed when a 20 mm film is formed).

In the ALD method, for example, in the case of forming an SiO ₂ film, high quality film formation is possible at a low temperature of approximately 200 ° C. to 600 ° C.

  First, as described above, the wafer 11 is loaded into the boat 23 and loaded into the processing chamber 34. After loading the boat 23, the steps described below are sequentially executed.

  (Step 1) After the valve 52 is opened and the processing chamber 34 is evacuated by the vacuum pump 53, the valve 52 is opened and the first gas is supplied into the processing chamber 34. Since TDMAS, which is the first gas, is a liquid material, the flow rate is controlled by being vaporized by the liquid material supply unit. The valve 38a is opened for a certain period of time, and the raw material is supplied into the processing chamber 34 to adsorb the first raw material onto the wafer 11. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example. Thereafter, the valve 38a is closed.

  (Step 2) Thereafter, in order to discharge the first raw material in the processing chamber 34, a carrier gas flows from the carrier gas supply pipe 39a and the flow rate is adjusted by the mass flow controller 37e. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example.

  (Step 3) The valve 38b is opened to supply the second gas to the processing chamber 34. The flow rate of ozone as the second gas is controlled by the ozone supply unit. The valve 38b is opened for a certain time to supply the raw material to the processing chamber 34. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example. Thereafter, the valve 38b is closed.

  (Step 4) Thereafter, in order to discharge the second raw material in the processing chamber 34, a carrier gas is flowed from the carrier gas supply pipe 39b, and the flow rate is adjusted by the mass flow controller 37d. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example.

(Step 5) The valve 38c is opened to supply the third gas to the processing chamber. The flow rate of the third gas H ₂ O is controlled by the mass flow controller 37c. The valve 38c is opened for a certain time to supply the raw material to the processing chamber 34 and supply the third raw material. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example. Thereafter, the valve 38c is closed.

  (Step 6) Thereafter, in order to discharge the third raw material in the processing chamber 34, a carrier gas is flowed from the carrier gas supply pipe 39b, and the flow rate is adjusted by the mass flow controller 37d. At this time, the pressure in the processing chamber 34 is in the range of 1 to 266 Pa, and is maintained at 66 Pa, for example.

  After the steps 1 to 6 are repeated until a desired film thickness is formed, the processing chamber 34 is evacuated to discharge the raw material gas, and then the pressure is restored to atmospheric pressure by the barge gas.

As described above, a plurality of processing substrates are stacked in multiple stages and placed in the processing chamber 34, and after supplying the first raw material (metal compound or silicon compound raw material), the second raw material (oxidizing raw material). And, after that, by forming an oxide film by the ALD (Atomic Layer Deposition) method in which the third raw material (H ₂ O) is alternately supplied, the surface flatness is promoted by promoting the adsorption of the metal compound raw material. And a metal oxide film with good step coverage can be obtained.

  According to the present invention, the problem of step coverage and loading effect as described above in forming a thin film of metal oxide is eliminated, and a metal compound is adsorbed on the surface of a wafer (step) at a low temperature in a short time, thereby flattening the surface. It is possible to provide a metal oxide thin film forming method and a semiconductor device manufacturing method that are excellent in performance and step coverage and have no loading effect.

Examples of the metal oxide film include Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , RuO ₂ , IrO ₂ , and SiO ₂ .

(Appendix)
The present invention includes the following embodiments.

  (Supplementary note 1) a step of carrying at least one substrate into the processing chamber, a metal compound or silicon compound as a first raw material, an oxidizing raw material containing oxygen atoms as a second raw material, and a third raw material A step of repeatedly supplying a reaction agent capable of forming an OH-terminated surface to the processing chamber a predetermined number of times to deposit metal oxide or silicon oxide on the substrate surface; and treating the substrate with the treatment In the step of carrying out the chamber and the step of depositing the metal oxide film or the silicon oxide film, after supplying the first raw material, the second raw material, and the third raw material, the inside of the processing chamber is not treated. A method for manufacturing a semiconductor device, comprising a step of purging with an active gas.

(Supplementary note 2) The metal oxide film or silicon oxide film is selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , RuO ₂ , IrO ₂ , SiO _2, etc. A method for manufacturing a semiconductor device.

  (Supplementary Note 3) As the metal compound as the first raw material, an organic compound containing an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, a silicon atom, or a chloride of the above atom is used as a raw material. The manufacturing method of the semiconductor device of appendix 1.

(Supplementary Note 4) The first organic compound is a raw _{^{material, MH n [OCR 1 R 2}} R 3] mn, MH n [NR 4 R 5] the production method according to Supplementary Note 1 of the semiconductor device is _mn.

However, M shows the metal containing each atom of Additional remark 3, m is the stable valence of this metal, n is an integer of 0-2, However, when M is atoms other than a silicon, it represents 0, R ^1-5 is an alkyl group which may contain an ether bond in the middle of 1 to 4 carbon atoms.

As (Supplementary Note 5) the second raw material, ozone (O _3), hydrogen peroxide (H ₂ O _2), nitrous oxide (N ₂ O), nitrogen monoxide (NO), nitrogen dioxide (NO _2), The method of manufacturing a semiconductor device according to appendix 1, wherein oxygen (O ₂ ) or atomic oxygen is used.

As a reaction reagent capable of forming an OH terminated surface is (Supplementary Note 6) The third raw material, mixing of H ₂ O or activated hydrogen and activated oxygen, or OH radical, OH ions, or hydrogen, oxygen or The method of manufacturing a semiconductor device according to appendix 1, wherein one of the raw materials is an activated raw material.

(Supplementary Note 7) helium (He) as the inert gas, neon (Ne), argon (Ar), nitrogen (N ₂₎ the production method according to Supplementary Note 1 of the semiconductor device used.

  (Additional remark 8) The manufacturing method of the semiconductor device of Additional remark 1 whose temperature which irradiates a said 3rd raw material is 100 to 300 degreeC, Preferably it is 130 to 180 degreeC, More preferably, it is 155 to 165 degreeC.

It is explanatory drawing which shows the reaction system which can form OH termination | terminus surface. It is the schematic of the multiple reflection IR spectroscopy analyzer used by this invention. Is a graph showing of H ₂ O adsorption properties of the SiO ₂ top measured by multiple reflection IR spectrometer. It is a graph showing the TDMAS adsorption | suction characteristic to OH termination | terminus surface. (A) and (B) are graphs comparing the amount of adsorption of TDMAS and TEMAH when ozone oxidation or ozone and H ₂ O oxidation is performed. It is an infrared absorption spectrum when irradiated with 160 ° C. H ₂ O ozone oxidized surface. Is an infrared absorption spectrum of Si surface irradiated of H ₂ O on the ozone oxidized surface. It is an infrared absorption spectrum when irradiated with 160 ° C. H ₂ O ozone oxidized surface. Is an infrared absorption spectrum of Si surface irradiated of H ₂ O on the ozone oxidized surface. It is explanatory drawing which shows the film-forming mechanism. It is a process sequence diagram of oxide film formation. 1 is a perspective view of a semiconductor manufacturing apparatus according to an embodiment of the present invention. It is a sectional side view of the semiconductor manufacturing apparatus which concerns on embodiment of this invention. It is an elevation sectional view showing a processing furnace of a semiconductor manufacturing device concerning an embodiment of the invention. It is a plane sectional view of the processing furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multiple reflection IR spectroscopy analyzer 2 Si prism 10 Semiconductor manufacturing apparatus 11 Wafer 23 Boat 24 Processing furnace 34 Processing chamber 36a 1st gas supply pipe 36b 2nd gas supply pipe 36c 3rd gas supply pipe 39a Carrier gas supply pipe 39b Carrier gas Supply pipe 41 First nozzle 42 Second nozzle 51 Gas exhaust pipe 53 Vacuum pump

Claims (5)

A first step of carrying the substrate into the processing chamber; a second step of supplying a first raw material that is a metal compound or a silicon compound to the processing chamber; and a third step of exhausting the atmosphere of the processing chamber. A fourth step of introducing a second raw material that is an O-containing gas into the processing chamber; a fifth step of exhausting the atmosphere of the processing chamber; and a sixth step of exposing H ₂ O to the surface of the substrate. A process, a seventh process of exhausting the atmosphere of the processing chamber, and an eighth process of unloading the substrate from the processing chamber, and repeating the seventh process from the second process in order a predetermined number of times. A substrate processing method for forming a metal oxide film or a silicon oxide film on the surface of the substrate, wherein the sixth step is performed while heating the substrate in a temperature range of 155 ° C. to 165 ° C. The substrate processing method characterized by performing. _2. The substrate processing method according to claim 1, wherein the metal oxide film or silicon oxide film is selected from Al ₂ O ₃ , TiO ₂ , ZrO ₂ , HfO ₂ , Ta ₂ O ₅ , RuO ₂ , IrO ₂ , SiO _{2 and the} like. .   The first raw material is an organic compound containing any one of an aluminum atom, a titanium atom, a zirconium atom, a hafnium atom, a tantalum atom, a ruthenium atom, an iridium atom, and a silicon atom as a metal compound, or a chloride of any of the above atoms. The substrate processing method according to claim 1. The substrate processing method according to claim 1, wherein the second raw material is any one of ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), and oxygen (O ₂ ). The substrate processing method according to claim 1, wherein H ₂ O is introduced into the processing chamber in the sixth step.