JP2000080476A - Vapor growth method, vapor growth device and ammonium halide removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a silicon nitride thin film excellent in a coverage and uniform in film thickness on a substrate with high productivity in a high yield by feeding a silicon compd. such as a silane compd. NH3, hydrazine, HCL to a reaction chamber as reaction gas and executing vapor growth. SOLUTION: A silicon compd. such as SiH4-x(NH2)x (where x>=2), SiH2NH, Si(NH)2, (SiH2NH)x, NH2(SiH2NH)xSiH2NH2 (where X>1), SiH4-x(NHR)x (where x>=2), SiH4-x-y (NH2)x (NHR)y (where x+y <=4, x>=1 and y>=1), SixNyHz (where y>=2), SixNyHzFu (R is H, F or a 1-3C hydrocarbon group substitutable with fluorine) is used as reaction gas and is fed to a reaction chamber together with NH3, hydrazine or the derivative thereof, HCl or the like. In this place, vapor growth is executed at 500 to 800 deg.C under 0.1 to 60 Torr, and a silicon nitride film is formed on a substrate 2 placed on a turn table 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth method, a vapor phase growth apparatus and an ammonium halide removing apparatus which can be used for manufacturing semiconductors and the like. More specifically, the present invention relates to a method and an apparatus for forming a silicon nitride film on a surface of a semiconductor substrate by a vapor deposition method.

[0002]

2. Description of the Related Art Conventionally, when a silicon nitride (SiNx) film is grown on a surface of a semiconductor substrate, a thin film is generally formed by a CVD method using dichlorosilane and ammonia as raw material gases.

[0003]

However, when dichlorosilane and ammonia are used as raw material gases, ammonium chloride is generated as a reaction product. Dichlorosilane and ammonia react only by mixing to produce ammonium chloride. Therefore, if an attempt is made to supply the reaction mixture to the reaction chamber after mixing in advance, the piping upstream of the reaction chamber may be blocked. For this reason, conventionally, mixing has been carried out immediately upstream of the reaction chamber as much as possible, or mixing has been carried out in the reaction chamber. However, this case causes clogging of piping and pumps downstream of the reaction chamber. In addition, the ammonium chloride may remain as particles on the wafer, which is a factor that deteriorates the yield when manufacturing semiconductor devices. In addition, since ammonium chloride adheres to exhaust pipes and pumps, periodic maintenance of these manufacturing apparatuses is required. This is a factor that reduces the productivity of the device. In order to solve such a problem, attempts have been made to combine monosilane and ammonia into a raw material gas. In this combination, there is no formation of ammonium chloride. However, the coverage was poor and it was difficult to obtain a uniform film thickness.

[0004] From such a thing, excellent coverage,
In order to produce a thin film having a uniform thickness, with good productivity, a method and apparatus for producing a silicon nitride film capable of suppressing a decrease in yield due to ammonium chloride, or a silicon nitride film capable of suppressing generation of ammonium chloride A method and apparatus has been desired.

[0005]

[Summary of the Invention] <Summary> An apparatus for removing ammonium halide according to the present invention comprises:
A source gas containing a silane compound and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof is supplied, and a reaction chamber for reacting the source gas, and halogenating the reaction gas generated by the reaction are used. It has a removing device for removing ammonium, and a gas discharging device for discharging from the removing device a gas from which the ammonium halide has been removed from the reaction gas. Further, the vapor phase growth apparatus of the present invention,
A supply source for supplying a silane compound, ammonia, or a compound selected from the group consisting of hydrazine or a derivative thereof, a supply source for supplying the silane compound,
A pre-reaction chamber for reacting the ammonia, or a compound selected from the group consisting of hydrazine or a derivative thereof, a removing device for removing ammonium halide from a reaction gas generated by the reaction, and the halogen from the reaction gas. A reaction chamber for forming a silicon nitride film on a substrate disposed therein by using a reaction gas from which ammonium chloride is removed.

Further, in the vapor phase growth method of the present invention, a step of supplying a silane compound and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof as a raw material gas to a preliminary reaction chamber; In the reaction chamber,
A step of reacting a silane compound with a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof; a step of removing ammonium halide generated by the reaction; and a reaction in which the ammonium halide is removed. A step of supplying a gas to the reaction chamber; and a step of forming a silicon nitride film on a substrate provided in the reaction chamber by using the reaction gas. Further, the vapor phase growth method of the present invention provides
4-x (NH2) x (where x ≧ 2) or SiH
2NH or Si (NH) 2 or (SiH2
NH) x or NH2 (SiH2NH) xSiH2
NH2 (where x> 1) or SiH4-x (NH
R) x (where x ≧ 2) or SiH4-xy
(NH2) x (NHR) y (where x + y ≦ 4, x ≧
1, y ≧ 1) or SixNyHz (where y ≧
2) or SixNyHzFu, where R is H,
F, a step of supplying a reaction gas, which is a hydrocarbon group having 1 to 3 carbon atoms capable of substituting fluorine, to a reaction chamber; and using the reaction gas, a silicon nitride film on a substrate disposed in the reaction chamber. And a step of forming

<Effects> According to the present invention, the yield and the productivity of an apparatus for producing a semiconductor device by forming a silicon nitride film on a substrate by previously producing and removing ammonium halide are reduced. It can be greatly improved. [Detailed Description of the Invention] First vapor phase growth method The first vapor phase growth method of the present invention can provide excellent coverage and a uniform film thickness without generating ammonium chloride. . <Silicon Compound> As the silicon compound that can be used in the present invention, any compound can be used as long as it can be used in a vapor phase growth method. As such a compound, a silane compound (for example, monosilane, disilane, trisilane, and tetrasilane) is one of the preferable ones, but a halide or an organic derivative of the silane compound may be used. However, when it is a halide, it is preferably a fluoride. Most preferred is monosilane or disilane. In addition, these silicon compounds can be used in any combination. The silane compound is SiH4-x (NH
2) x (however, x ≧ 2), or SiH2NH, or Si (NH) 2, or (SiH2NH) x, or NH2 (SiH2NH) xSiH2NH2 (where x> 1), or SiH4-x (NHR) x ( Where x ≧ 2) or SiH4-xy (NH2) x
(NHR) y (where x + y ≦ 4, x ≧ 1, y ≧ 1),
Or SixNyHz (however, y ≧ 2) or S
ixNyHzFu, and R can be represented by a hydrocarbon group having 1 to 3 carbon atoms which can be substituted with H, F, and fluorine.

<Hydrazine or a derivative thereof> As the hydrazine or a derivative thereof that can be used in the present invention, any compound can be used as long as it can be used in a vapor phase growth method. Among such compounds, the compounds of the above formula (1) are preferred. Among the compounds represented by the formula (1), hydrazine H2NNH
2, monomethylhydrazine H2NNHCH3, or N, N-dimethylhydrazine H2NN (CH3) 2, t
-Butylhydrazine H (CH3) 3NNH2 is most preferred. These hydrazine compounds can be used in any combination. In addition, these hydrazine compounds can be combined with NH3 and supplied simultaneously. <First vapor-phase growth method> In a first vapor-phase growth method of the present invention, a silicon nitride film is formed on a substrate using the above-mentioned silicon compound and the above-mentioned hydrazine or its derivative as a source gas. It is characterized by the following. Note that other gases can be added as raw materials as long as the effects of the present invention are not impaired. Here, the step means a trench on the substrate. The vapor phase growth is performed under arbitrary conditions using a general vapor phase growth apparatus, for example, the one shown in FIG.
C. and a pressure of 0.1 to 760 Torr.

In one embodiment of the vapor phase growth method of the present invention, the semiconductor substrate on which the silicon nitride film is to be formed is placed on a flat surface on which the thin film is to be formed so that the formed thin film is uniform. And rotate it horizontally. The rotation speed at this time is also arbitrary, but is preferably 50 to 500.
Rotate in the range of 0 rpm. Further, by controlling the rotation, the film composition of the silicon nitride film formed can be controlled. Furthermore, the mixing ratio and supply amount of the silicon compound and hydrazine or a derivative thereof as the raw material gas are not particularly limited. The mixing ratio of the silicon compound and hydrazine or a derivative thereof is 1: 1 to 1: 100 in molar ratio, and the supply rate is, for example, 0.01 to 10 liters when forming a silicon nitride film on a substrate having a diameter of 20 cm. / Min silicon compound source gas. By controlling these conditions for vapor phase growth, it is also possible to control the properties of the silicon nitride film. Although silicon nitride is most typically represented by Si3N4, the chemical composition of the actual silicon nitride film is not stoichiometric. For example, as shown in FIGS. 3 to 5, the Si / N ratio tends to decrease when the temperature is increased or the supply amount of the source gas is increased, and the Si / N ratio tends to increase when the rotation speed of the substrate is increased. is there. The mixing ratio of the silicon compound as the raw material and hydrazine or a derivative thereof is generally selected in the range of 1: 1 to 1: 100. Changing the ratio can also change the composition of the silicon nitride film. it can.

As the apparatus that can be used in the vapor phase growth method of the present invention, any apparatus can be used as long as it can be generally used in the vapor phase growth method. Second vapor-phase growth method The second vapor-phase growth method according to the present invention is a method for producing, in advance, an ammonium halide (for example, ammonium chloride) which is a by-product which has conventionally been a problem, and removing the raw material after removing it. A silicon nitride film is formed using a gas. <Raw material gas> The raw material gas that can be used in the second vapor phase growth method of the present invention is a halogenated silane compound and ammonia. The halogenated silane compound is not particularly limited, but a chlorinated silane compound is preferable. Examples of preferred halogenated silane compounds are chlorides of monosilane, disilane, trisilane, and tetrasilane, and more specifically, dichlorosilane, chlorosilane, dichlorodisilane, and the like. Further, the halogenated silane compound used in the present invention,
Chlorinated silane compounds are preferred, but may be substituted by organic groups or fluorine in addition to chlorine.
These halogenated silane compounds can be used in any combination. In addition to the halogenated silane compound and ammonia, other gases can be used as long as the effects of the present invention are not impaired.

<Second Vapor Phase Growth Method> In the vapor phase growth method of the present invention, a reaction gas is supplied after preliminarily reacting the above-mentioned source gas and removing generated ammonium halide (ammonium chloride). And forming a silicon nitride film on the substrate. The pre-reaction method is by mixing.
If necessary, the mixed raw material gas can be retained and the preliminary reaction can be promoted by means such as stirring. The mixing ratio between the halogenated silane compound and ammonia gas is arbitrary, but is generally from 1: 1 to 1: 100 in molar ratio.
It is. The reaction conditions for the preliminary reaction are generally performed at a temperature of 0 to 500 ° C. and a pressure of 0.1 to 760 Torr. A reaction occurs by the mixing of such source gases, and ammonium halide, silicon, and a compound containing nitrogen, chlorine, and hydrogen are generated. This ammonium chloride is generally gaseous at a high temperature at which vapor phase growth is performed, but solidifies and precipitates at about room temperature. In the vapor phase growth method of the present invention, ammonium halide is positively precipitated in this preliminary reaction, and the reaction gas after removing it is supplied to the vapor phase growth reaction. Means for removing the precipitated ammonium halide is optional. For example, as shown in FIG. 6, a gas immediately after mixing the halogenated silane compound and ammonia is led to a large-diameter pipe, and Depositing ammonium halide on the surface, and performing vapor phase growth while switching the large-diameter piping as needed, or introducing the raw material gas immediately after mixing to a large-capacity retention tank where the ammonium halide is deposited. The ammonium halide can be removed by a suitable filter. By controlling the temperature of the portion to be deposited at an appropriate temperature, ammonium halide can be removed more efficiently. For example,
The temperature of the portion to be deposited is set lower than the sublimation temperature of ammonium halide, and is set at a temperature (for example, 0 ° C.) at which a reaction product generated by the preliminary reaction and contributing to the formation of the silicon nitride film is not deposited.

By removing the ammonium halide in advance in this way, the problem of particles in the reaction chamber for performing vapor phase growth is improved. The raw material gas from which the ammonium halide has been removed in this way is then supplied to a reaction chamber and subjected to a vapor phase growth reaction. Before that, if necessary,
Other gases can be mixed. Examples of such a gas include a gas contributing to vapor phase growth such as hydrochloric acid gas and ammonia gas. Usually, the preliminary reaction is performed in one stage, but can be performed in two stages as necessary. In this case, the reaction conditions of the first-stage preliminary reaction and the second-stage preliminary reaction, such as temperature or pressure, can be changed, and after the first-stage preliminary reaction, an additional gas such as hydrochloric acid is added. Gas or ammonia gas can also be added. The reaction conditions for performing the vapor phase growth reaction are generally 600 to 1000 ° C. and a pressure of 0.1 to 76.
0 Torr. Alternatively, the reaction gas after the halogenated silane compound and ammonia are preliminarily reacted to remove the ammonium halide may be stored. The stored gas is introduced into a reaction chamber in which a substrate on which a silicon nitride film is to be formed is placed under a condition where a vapor phase growth reaction occurs when necessary, to form a silicon nitride film.

This second vapor phase growth method can be performed by a specific vapor phase growth apparatus. Such a vapor phase growth apparatus includes a supply source capable of supplying a silane compound, ammonia,
Alternatively, a compound selected from the group consisting of hydrazine or a derivative thereof, and a supply source capable of supplying a silane compound, and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof, and a pre-reaction chamber for pre-reaction. Means comprising means for removing ammonium chloride generated in a preliminary reaction chamber, and a reaction chamber for taking in a reaction gas after removing ammonium chloride and forming a silicon nitride film on a substrate disposed therein It is. An example of such a vapor phase growth apparatus is as shown in FIG. This apparatus comprises a reaction chamber 1, a turntable 3 for mounting a substrate 2 provided in the reaction chamber 1, a heater 4 for heating the substrate 2, and a preliminary reaction chamber 5. The substrate 2 is mounted on a turntable 3, and a raw material gas or the like supplied via a preliminary reaction chamber 5 is heated by a heater 4 to form a film on the substrate 2. As the preliminary reaction chamber 5 and the means for removing ammonium halide, those described above can be used. Further, as shown in FIG. 7, a pre-reactor can be provided in two stages. Here, the preliminary reaction device includes preliminary reaction chambers 5 and 6, and may further include a unit for introducing another gas into the reaction gas after the preliminary reaction. Such a means can be used even when the preliminary reactor is used in two stages. Such an apparatus is used in the portion A of FIG. 6 or the portion B of FIG.

[0014] The gas produced by pre-reacting SiH 2 Cl and NH 3 may contain a highly reactive gas. Such highly reactive gases can degrade coverage. On the other hand, when such a highly reactive gas passes through a reaction tube close to the film forming temperature, it immediately adheres to the reaction tube and accumulates (deposits) and disappears. Even if a gas having low reactivity is allowed to flow through a reaction tube close to the reaction temperature, the gas adheres to the inner wall and deposits hardly occur. For this reason, a film with good coverage can be obtained by setting the temperature of the preliminary reaction tube to be substantially the same as the film forming temperature so that the highly reactive gas has a residence time of such an extent that it disappears.
Specifically, as shown in FIG. 8, the pre-reacted product gas is passed through a pre-reaction tube set at approximately the same temperature as the film formation temperature by an electric furnace 7 and then sent to a vapor phase growth apparatus. Supply. Through such a process, a gas with low reactivity can be supplied to the reaction chamber, and a film with good coverage can be obtained over the substrate. First, a reaction between SIH2Cl2 and NH3 will be described below as an example. As shown in reaction (3), SiH2Cl2 and NH3 react to form SiH2ClN
H2 and HCl are formed.

Further, as shown in reaction (4), SiH2
When ClNH2 and NH3 react, SiH2 (NH2)
2 and NH3 are produced. As shown in reaction (5), S
When iH2 (NH2) 2 is decomposed, Si2NH and NH3 are generated. On the other hand, as shown in reaction (6), SiH 2 Cl
When NH2 reacts with SiH2Cl2, NH (SiH2
Cl) 2 is produced. As shown in reaction (7), NH
When (SiH2Cl) 2 reacts with NH3, NH2Si
H2NHSiH2Cl is formed. As shown in the reaction (8), the NH2 group and the Cl group in the NH2SiH2NHSiH2Cl molecule react with each other to generate a cyclic compound (NHSi2) 2 and HCl. As shown in reaction (9), NH2
The reaction between SiH2NHSiH2Cl and NH3 produces NH2SiH2NHSiH2NH2.
As described above, the Si—Cl bond in the raw materials and products is
By reacting with H3, the Cl atom is replaced by an NH2 group, and the NH2 group in the product reacts with the Si--Cl bond to form N--S
An i-bond is created. When the raw material is SiHCl3 or SiCl4, for example, SiH (NH2) 3 or Si (NH2) 4
Is generated.

As the reaction progresses, Si—N bonds are complicatedly combined to form NH 2 (SiH 2 NH) x SiH 2
Compounds having a structure like NH2, cyclic compounds (NH
2 to 4 N atoms are bonded to SiH3) x or Si atoms to generate a compound having a branched structure or the like. Here, a similar reaction can occur when the Cl atom is another halogen atom.

[0017]

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Embedded image In addition, the reaction between Si2H6 and monomethylhydrazine is caused by decomposition of Si2H6 as shown in reaction (10).
2, which is the monomethylhydrazine NN, N
-H or N-CH3 bond, and as shown in reaction (11), SiH2NH2NHCH3, SiH3HNN
It is believed that HCH3, and others, form.

[0018]

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Embedded image When SiH4 reacts with NH3, the reaction (12)
As shown in (2), Si2H6 is decomposed into SiH2, and SiH2 reacts with NH3 to make (13) to (15).
SiH3NH2, SiHNH2SiH2N
It is believed that H2, Si (NH2) 2, SiH (NH2) 3 and others occur. It is considered that a similar reaction proceeds when Si2H6 reacts with NH3.

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Embedded image As described above, since various reaction products are considered to be generated, the SiN film to be formed is unlikely to be Si-rich if one having a high ratio of N to Si is used among them. In order to obtain desired film-forming properties, the above-mentioned compounds which do not contain NH3 and halogen can be used as a source gas, or HCl can be used together with the above-mentioned compounds to obtain a source gas. Further, a plurality of compounds can be selected from the above-mentioned compounds. Further, the supply amount of the compound selected from the group consisting of ammonia, hydrazine and their derivatives is excessive with respect to the supply amount of the halogenated silane compound supplied to the preliminary reactor, whereby the halogenated silane compound is supplied. Halogen contained therein easily reacts completely with ammonia or the like. This makes it easier to remove halogen components,
Furthermore, deposits that accumulate in the reactor or the exhaust pipe are almost eliminated, so that wafer-like particles are reduced, and deposits in the reactor and the pipes are also reduced.

The gas generated by the preliminary reaction is decomposed by a reverse reaction or a unimolecular decomposition reaction to produce ammonia,
Produces hydrazine, or derivatives thereof. Therefore, the decomposition of the generated gas can be suppressed by adding ammonia, hydrazine, or a derivative thereof to the gas after the preliminary reaction. The same effect can be obtained even if the gas generated by the preliminary reaction is stored in an excess amount of ammonia, hydrazine, or a derivative thereof. An ammonium halide removing device alone without the reaction chamber 1 from this vapor phase growth apparatus can be provided in an existing vapor phase growth apparatus. The constitution is such that a source gas containing a silane compound and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof is supplied, a reaction chamber for reacting the source gas, and a reaction generated by the reaction. A removing device for removing the ammonium halide from the gas; and a gas discharging device for discharging the gas from which the ammonium halide has been removed from the reaction gas from the removing device. Source gases are supplied to the reaction chamber and mixed, and cause a chemical reaction under predetermined chemical reaction conditions. The removing device removes the ammonium halide from the reaction gas generated by the chemical reaction. The means for removing is the same as the means described above.

The reaction gas from which ammonium chloride has been removed is discharged from the reaction chamber by a gas discharge device. The discharged reaction gas can be supplied to a reaction chamber in which a substrate on which a film is to be formed is arranged. The removing device may be provided inside the reaction chamber or may be provided outside. Further, the gas discharge device discharges the gas after the reaction by pushing or pulling the gas after the reaction by a pump provided inside and outside the reaction chamber. With such a configuration and operation,
It is only necessary to newly provide an existing vapor phase growth apparatus, and the apparatus can be easily installed and operated. Third vapor phase growth method <Compound containing silicon and nitrogen> In the third vapor phase growth method of the present invention, a compound containing silicon and nitrogen is used as a source gas. Any such compound can be used as long as it contains silicon and nitrogen and can be treated as a gas when used in a vapor phase growth method. Among such compounds, a compound represented by the following formula (16) is preferable.

Embedded image Here, k is 1 to 4, and R2 is H,
F is a hydrocarbon group having 1 to 3 carbon atoms which may be substituted by fluorine, or an amino group which may be substituted by a hydrocarbon group having 1 to 3 carbon atoms, and all R2s may be the same or different At least one of all R2 is an amino group which may be substituted by a hydrocarbon group having 1 to 3 carbon atoms.

As R2, a fluorinated hydrocarbon group or the like can be used. However, if the molecular weight is too large, it is difficult to vaporize the compound, and care should be taken because handling may be problematic. In addition, the compound of the formula (17) may be chlorinated if necessary, but care must be taken since problems such as generation of ammonium chloride may occur. A specific example of such a compound is H2N
SiH2NH2, H2NSiH2NHCH3, H2NS
iH3, H2NSiH2CH3, and others. These compounds can be used in any combination. <Third vapor phase epitaxy method> The third vapor phase epitaxy method of the present invention is performed in the same manner as other vapor phase epitaxy methods except that a compound containing silicon and nitrogen is used as a source gas. Can be. The reaction conditions for carrying out the vapor phase growth reaction are:
The temperature is from 00 to 1000 ° C. and the pressure is from 0.1 to 760 Torr. By controlling these conditions, the composition of the silicon nitride film to be formed can be controlled by the above-described first and second compositions.
Is the same as the vapor phase growth method. Fourth vapor phase growth method SiH4-x (NH2) x (where x ≧ 2), or SiH2NH, or Si (NH) 2, or (S
iH2NH) x or NH2 (SiH2NH) xS
iH2NH2 (where x> 1) or SiH4-x
(NHR) x (where x ≧ 2) or SiH4-x
−y (NH2) x (NHR) y (where x + y ≦ 4, x
≧ 1, y ≧ 1) or SixNyHz (however, y ≧
2) or SixNyHzFu, where R is H,
F, a step of supplying a reaction gas, which is a hydrocarbon group having 1 to 3 carbon atoms capable of substituting fluorine, to a reaction chamber; and using the reaction gas, a silicon nitride film on a substrate disposed in the reaction chamber. And a step of forming.

Since the source gas does not contain Cl atoms and ammonium chloride is not generated by a chemical reaction, a good silicon nitride film can be formed on the substrate. NH3, hydrazine or a derivative thereof, or HCl may be supplied to the source gas. Further, in the present invention, a film-forming species having good coverage in the trench has low reactivity, and is therefore often included in exhaust gas from the reactor. In such a case, FIG.
It is also possible to use a vapor phase growth apparatus such as that described above. here,
FIG. 9 shows an example in which a halogenated silane compound is reacted with a compound comprising ammonia, hydrazine, and a derivative thereof as a raw material. Here, the exhaust gas is passed through a separator, and the separated film-forming species are supplied to the reactor again as it is or after being stored. Means for separating film-forming species from exhaust gas include membrane separation, adsorption, distillation, and the like. As the separation means,
An example in which membrane separation is used will be described below. The gas supplied from the preliminary reactor 5 is used for film formation in the reactor 1, and unreacted gas is discharged from the reactor. The pressure in the reactor 1 is maintained at a predetermined pressure by a pressure regulating valve 9. The exhausted gas is pressurized by the pump 10. The pressurized gas passes through the filter 11 and is supplied to the membrane separator 12A after the solid components are removed.

In the membrane separator 12, a gas having a smaller molecular weight than the main component supplied from the pre-reactor 5 is first separated by the semipermeable membrane, and the treated gas is further separated into a gas having a larger molecular weight in the membrane separator 12B. Separated. Those having a smaller molecular weight and those having a larger molecular weight than the main components supplied from the preliminary reactor 5 are discharged by the pump 13. Preliminary reactor 5
The gas having a molecular weight substantially equal to that of the main component supplied from is purified by removing impurities in the purifier 14 filled with the adsorbent. The purified gas is supplied to the pressure regulator 18
After the pressure is adjusted by the above, the mixture is supplied to the reactor 1.
In this example, the gas generated in the preliminary reactor 5 is described as an example. However, in the case of other gases, the film-forming species can be recovered from the exhaust gas in the same manner. Further, a method other than the membrane separation can be used as the separation device.

[0024]

Embodiment 1 A silicon nitride film was formed using Si2H6 and H2NNHCH3 (hereinafter referred to as MMH) as source gases and N2 as a carrier gas. Film formation temperature 600 ° C-700
SiNx with good coverage as shown in FIG. 2 in the range of ℃, pressure 38 Torr, wafer rotation speed 5000 rpm or less.
A film could be obtained. FIG. 2 is a diagram showing that a film having a uniform thickness can be obtained even in a concave portion on a substrate. Further, as shown in FIGS. 3 to 5, it was possible to control the composition of the silicon nitride film by changing the temperature, the number of revolutions, and the flow rate of the source gas. FIG. 3 is a diagram showing a change in the Si / N ratio of the film when the temperature of the substrate is changed. The film formation conditions are as follows: the flow rate of Si2H6 is 100 ccm;
The flow rate of H is 1.5 liter m, the flow rate of N2 is 7 liter m, the wafer rotation speed is 1200 rpm, and the pressure is 38 Torr.
Met. In the range shown in this figure, it can be seen that the Si / N ratio tends to increase slightly when the temperature is increased. FIG. 4 shows the Si / of the film when the rotation speed of the turntable was changed.
It is a figure showing change of N ratio. The film formation conditions were as follows: the flow rate of Si2H6 was 100 ccm, the flow rate of MMH was 1.5 liters, the flow rate of N2 was 7 liters, the pressure was 38 Torr,
The temperature was 640 ° C. Depending on the rotation speed of the wafer, Si /
It can be seen that the N ratio fluctuates.

FIG. 5 is a diagram showing a change in the Si / N ratio when the flow rate of MMH is changed. Film formation conditions are Si2H
6, the flow rate of 100 ccm, the flow rate of N2 is 7 liters m,
The wafer rotation speed was 1200 rpm, the pressure was 38 Torr, and the temperature was 640 ° C. In the range shown in this figure, it can be seen that when the flow rate of MMH is increased, the Si / N ratio tends to slightly decrease. In these film forming experiments, adhesion of ammonium chloride was not recognized on the inside of the reaction chamber or the inner surface of the exhaust pipe. Example 2 A silicon nitride film was formed by using SiH 2 Cl 2 and NH 3 as source gases and supplying a gas which had been subjected to a preliminary reaction in a preliminary reactor shown in FIG. The temperature of the preliminary reactor 5 is about room temperature. Ammonium chloride was generated in the pre-reactor 5 and adhered to the inner wall of the pre-reactor 5. The tube diameter of the pre-reactor 5 is made sufficiently large so as not to block. A plurality of pre-reactors 5 are switched and used so that ammonium chloride adhering to the pre-reactors 5 can be removed without stopping the apparatus.
As a result, a silicon nitride film having good coverage could be obtained. No adhesion of ammonium chloride was observed in the reaction chamber 1. Although slight precipitation of ammonium chloride was observed on the inner surface of the exhaust pipe, precipitation of ammonium chloride on the inner surface of the exhaust pipe was observed by maintaining a part of the pipe between the preliminary reaction chamber 5 and the reaction chamber 1 at 0 ° C. lost.

Further, SiH4 is decompressed or reduced to a pressure near the atmospheric pressure, a temperature condition of about 700 ° C., and a residence time of 0.1 to
After reacting in a preliminary reaction tube for about 1 second and supplying it to a vapor phase growth apparatus, a desired film with good coverage could be obtained. Example 3 H2NSiH2NH2, H2NSiH as source gas
2NHCH3, H2NSiH3 or H2NSiH2C
H3 was supplied, and a silicon nitride film was formed on the substrate by a normal vapor deposition method. In each case, the coverage was good and the adhesion of the reaction product could be suppressed.

[0027]

According to the present invention, the yield in manufacturing semiconductor devices by the vapor phase growth method and the productivity of the apparatus can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a vapor phase growth apparatus that can be used in the vapor phase growth method of the present invention.

FIG. 2 is a schematic cross-sectional view of a silicon nitride film formed by a vapor deposition method of the present invention.

FIG. 3 is a diagram showing a change in the composition of a silicon nitride film when the temperature is changed in the vapor phase growth method of the present invention.

FIG. 4 is a view showing a change in the composition of a silicon nitride film when the number of rotations of a wafer is changed in the vapor phase growth method of the present invention.

FIG. 5 is a diagram showing a change in the composition of a silicon nitride film when the supply amount of hydrazine as a source gas is changed in the vapor phase growth method of the present invention.

FIG. 6 is a schematic view showing one example of a vapor phase growth apparatus of the present invention.

FIG. 7 is a schematic view showing a preliminary reactor that can be used in the vapor phase growth apparatus of the present invention.

FIG. 8 is a schematic diagram showing a preliminary reaction apparatus that can be used in the vapor phase growth apparatus of the present invention.

FIG. 9 is a schematic view showing an example of a vapor phase growth apparatus of the present invention, which is provided with a unit for collecting a film-forming species from exhaust gas.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Substrate 3 Turntable 4 Heater 5 Preliminary reaction chamber 6 Second preliminary reaction chamber

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoki Tamaki 1st address, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Toshimitsu Omine Toshiba Komine Toshiba, Koyuki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 town Toshiba R & D Center

Claims (18)

[Claims] (1) SiH4-x (NH2) x (where x ≧
2) or SiH2NH or Si (NH)
2, or (SiH2NH) x, or NH2 (S
iH2NH) xSiH2NH2 (where x> 1), SiH4-x (NHR) x (where x ≧ 2), or SiH4-xy (NH2) x (NHR) y (where x + y ≦ 4, x ≧ 1, y ≧ 1) or SixN
yHz (where y ≧ 2) or SixNyHzFu
R is H, F or a carbon atom capable of substituting fluorine for 1
Supplying a reaction gas that is a hydrocarbon group of any one of (1) to (3) to the reaction chamber; and forming a silicon nitride film on a substrate placed in the reaction chamber using the reaction gas. Vapor growth method. 2. The vapor phase growth method according to claim 1, wherein NH3, hydrazine or a derivative thereof, or HCl is supplied. 3. A step of supplying a halogenated silane compound and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof as a raw material gas to a preliminary reaction chamber; A silane compound,
Reacting ammonia or a compound selected from the group consisting of hydrazine or a derivative thereof; removing ammonium halide generated by the reaction; and reacting the reaction gas from which the ammonium halide has been removed with a reaction chamber. And a step of forming a silicon nitride film on a substrate disposed in the reaction chamber using the reaction gas. 4. The vapor phase growth method according to claim 3, wherein the compound selected from the group consisting of hydrazine or a derivative thereof is a compound represented by the following formula (1). Embedded image Here, R1 is H, F, or a hydrocarbon group having 1 to 3 carbon atoms which may be substituted by fluorine, and the four R1s may be the same or different. 5. The vapor phase growth method according to claim 3, wherein a hydrogen halide gas is mixed with the reaction gas from which the ammonium halide has been removed to form a silicon nitride film on the substrate. . 6. The method according to claim 3, wherein the silane compound contains Cl. 7. A supply amount of a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof supplied to the preliminary reaction chamber with respect to a supply amount of the silane compound supplied to the preliminary reaction chamber, 4. The supply amount of the silane compound is not less than the reaction equivalent.
The vapor phase growth method according to the above. 8. The vapor phase growth method according to claim 3, wherein the gas generated by the reaction in the preliminary reaction chamber contains ammonia or a hydrazine derivative. 9. A gas generated by a reaction in the preliminary reaction chamber is maintained at a temperature substantially equal to a film forming temperature of a film formed on the substrate before being supplied to the reaction chamber. 4. The vapor phase growth method according to claim 3, wherein the method is introduced into a reaction section. 10. The silane compound is SiH4-x (N
H2) x (where x ≧ 2), or SiH2NH, or Si (NH) 2, or (SiH2NH) x,
Alternatively, NH2 (SiH2NH) xSiH2NH2 (where x> 1), SiH4-x (NHR) x (where x ≧ 2), or SiH4-xy (NH2) x
(NHR) y (where x + y ≦ 4, x ≧ 1, y ≧ 1),
Or SixNyHz (however, y ≧ 2) or S
4. The method according to claim 3, wherein the method is ixNyHzFu. Here, R is a hydrocarbon group having 1 to 3 carbon atoms which can be substituted with H, F and fluorine. 11. The vapor phase growth method according to claim 3, wherein the gas supplied to the preliminary reaction chamber contains at least one molecule of siliconized hydrazine. 12. The method according to claim 12, wherein said molecule is combined with ammonia or HCl.
And supplying the silicon nitride film to the preliminary reaction chamber to form a silicon nitride film on the substrate. 13. A supply source for supplying a silane compound, a supply source for supplying a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof, and a supply source for supplying the silane compound and the ammonia or hydrazine or a derivative thereof. A pre-reaction chamber for reacting a compound selected from the group consisting of: a removing device for removing ammonium halide from a reaction gas generated by the reaction; and a reaction gas from which the ammonium halide is removed from the reaction gas. And a reaction chamber for forming a silicon nitride film on a substrate disposed therein using the method. 14. The silane compound is SiH4-x (N
H2) x (where x ≧ 2), or SiH2NH, or Si (NH) 2, or (SiH2NH) x,
Alternatively, NH2 (SiH2NH) xSiH2NH2 (where x> 1), SiH4-x (NHR) x (where x ≧ 2), or SiH4-xy (NH2) x
(NHR) y (where x + y ≦ 4, x ≧ 1, y ≧ 1),
Or SixNyHz (however, y ≧ 2) or S
14. The vapor phase growth apparatus according to claim 13, wherein the apparatus is ixNyHzFu. Here, R is a hydrocarbon group having 1 to 3 carbon atoms which can be substituted with H, F and fluorine. 15. The vapor phase growth apparatus according to claim 13, wherein the compound selected from the group consisting of hydrazine or a derivative thereof is a compound represented by the following formula (2). Embedded image Here, R1 is H, F, or a hydrocarbon group having 1 to 3 carbon atoms which may be substituted by fluorine, and the four R1s may be the same or different. 16. The vapor phase growth apparatus according to claim 13, wherein the raw material gas supplied to the preliminary reaction chamber has at least one molecule of hydrazine silicide. 17. The method according to claim 17, wherein the molecule is ammonia or HCl.
17. The vapor-phase growth apparatus according to claim 16, wherein the gas is supplied to the preliminary reaction chamber, and a silicon nitride film is formed on the substrate. 18. A raw material gas containing a silane compound and a compound selected from the group consisting of ammonia or hydrazine or a derivative thereof is supplied, a reaction chamber for reacting the raw material gas, and a reaction chamber formed by the reaction. A removing device for removing ammonium halide from a reaction gas, and a gas discharging device for discharging a gas from which the ammonium halide has been removed from the reaction gas, from the removing device, comprising: apparatus.