JP3334672B2 - Method of manufacturing semiconductor device and method of manufacturing capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and a method for manufacturing a capacitor, and more particularly, to a method for manufacturing a semiconductor device and a method for manufacturing a capacitor, which suppresses oxidation of a lower electrode constituting the capacitor.

[0002]

2. Description of the Related Art L which is known as a representative of a semiconductor device
SI (Large Scale Integrated Circuit) is broadly divided into memory products and logic products, and with the recent advance in semiconductor manufacturing technology, the former is particularly remarkable. Memory products include DRAM (Dynamic Random Access Memory) and
Although classified as SRAM (Static Random Access Memory), most of these memory products are constituted by MOS (Metal Oxide Semiconductor) transistors which are excellent in integration degree. In addition, DRAM is S
It is widely applied to various storage devices such as information devices because it can reduce the cost in order to make the most of the advantage of high integration as described above as compared with the RAM.

A DRAM uses a capacitor as an information storage capacitance element and stores information depending on the presence or absence of its charge. Therefore, the area occupied by individual capacitors formed on a semiconductor substrate with an increase in storage information capacity. Is restricted. Therefore, a device for increasing the capacitance (capacity) of each capacitor is required. If the capacitance of the capacitor does not have a value enough to store information, malfunctions easily occur due to an external noise signal or the like, and errors such as soft errors are likely to occur. .

In order to increase the capacitance of the above-mentioned capacitor, it is necessary to use an insulating material having a large dielectric constant as a capacitance insulating film. Conventionally, tantalum oxide, which is a kind of metal oxide film, has been used as a typical high dielectric constant insulating material. (Ta ₂ O ₅ ) film is widely used. This tantalum oxide film is a silicon oxide film (Si) conventionally used as a capacitance insulating film.
O ₂ ) has a dielectric constant approximately ten times as large as that of O ₂ ), and a silicon nitride film (Si ₃
N ₄ ) that is approximately four times as large as that of N ₄ )
have. Therefore, by forming a capacitor using a tantalum oxide film as a capacitor insulating film, a higher capacitance can be achieved.

FIGS. 16 (a) to 16 (c) and 17 (d),
(E) is a process drawing showing a manufacturing method of a conventional semiconductor device provided with a capacitor using the above-described tantalum oxide film as a capacitance insulating film in the order of steps. Hereinafter, a method for manufacturing the semiconductor device will be described in the order of steps with reference to FIG. First, as shown in FIG. 16A, for example, a well-known LOCOS (Local Oxidation
f Silicon), an element isolation insulating film 52 made of a silicon oxide film is formed, and then a silicon oxide film and a polycrystalline silicon film are sequentially formed in an active region surrounded by the element isolation insulating film 52. The gate oxide film 53 and the gate electrode (word line) 54 are formed by patterning the silicon oxide film and the polycrystalline silicon film into desired shapes. Next, by self-alignment using the gate oxide film 53 and the gate electrode 54 as a mask, an N-type impurity is
Then, after selectively forming an N-type diffusion region 55 constituting a source region or a drain region, an interlayer insulating film 56 made of a silicon oxide film or the like is formed on the entire surface.

Next, as shown in FIG. 16B, after forming a contact hole 57 in the interlayer insulating film 56 on the surface of the N-type diffusion region 55 by photolithography, the lower electrode film is entirely formed by sputtering. Titanium nitride film (T
iN) A film 58 is formed. Next, as shown in FIG. 16C, by CVD (Chemical Vapor Deposition) method.
A tantalum oxide film 59 serving as a capacitance insulating film is formed on the titanium nitride film 58 in an atmosphere containing oxygen.

FIG. 20 is a diagram showing a film forming sequence for forming the tantalum oxide film 59 described above. After the silicon substrate 51 is accommodated in the reaction furnace of the CVD apparatus, the time t
In 1, a tantalum pentaethoxy (Ta (OC ₂ H ₅ ) ₅ ) gas and an oxygen gas, which are source gases, are simultaneously supplied into the reaction furnace to start the formation of the tantalum oxide film 59. After the film forming process for a predetermined time T, the supply of the tantalum pentaethoxy gas and the oxygen gas is stopped at time t0.

Next, the silicon substrate 51 is placed on a UV (Ultra-V)
heat treatment (annealing treatment) in an oxidizing atmosphere of iolet) -O ₃ (low-temperature oxidation by ultraviolet irradiation in an ozone atmosphere)
By oxidizing the tantalum oxide film 59, the film quality is improved so that the tantalum oxide film 59 plays a sufficient role as a capacitance insulating film.

Next, as shown in FIG.
A titanium nitride film 60 serving as an upper electrode film is formed on the tantalum oxide film 59 by a method. Next, as shown in FIG. 17E, the titanium nitride film 5 is formed by photolithography.
8. By patterning the tantalum oxide film 59 and the titanium nitride film 60, the lower electrode 58A and the upper electrode 60
The capacitor 61 having a tantalum oxide film 59 interposed between the capacitor 61 and the capacitor A is completed.

In the method of manufacturing a semiconductor device described above, the tantalum oxide film 59 is formed and the silicon substrate 51 is formed.
During the heat treatment, oxygen in the atmosphere reacts with the titanium nitride film 58 serving as the lower electrode 58A, and a phenomenon occurs in which the lower electrode 58A is oxidized over substantially the entire thickness. That is, as shown in FIG. 17E, the lower electrode 58A is converted into a titanium oxide film 58B. Then, there is a disadvantage that the titanium oxide film 58B works as a low dielectric constant film. As described above, when the low dielectric constant film is formed, the low dielectric constant film (titanium oxide film 58B) is connected in series with the tantalum oxide film 59 which is a capacitance insulating film, so that the total capacitance of the capacitor 61 is low. Under the influence of the dielectric constant film, the capacitance is lower than that of the tantalum oxide film 59 alone.

FIG. 8 shows the sheet resistance ρs of the lower electrode made of a titanium nitride film. The value of the sheet resistance ρs is expressed as (low dielectric constant film such as a titanium oxide film on the surface as described above). It becomes relatively high as shown in A).
Therefore, it is not desirable as a lower electrode. Also,
FIG. 9 shows a silicon oxide film equivalent film thickness teq of a capacitor formed by using a tantalum oxide film as a capacitive insulating film on a lower electrode made of a titanium nitride film. When a dielectric film is formed,
The value becomes relatively large as shown in FIG. The silicon oxide film equivalent film thickness teq indicates a measure of the film thickness of the capacitance insulating film necessary to obtain a predetermined capacitance, and indicates that the smaller the capacitance, the better.

A method for manufacturing a semiconductor device in which the lower electrode of the capacitance is oxidized to prevent the formation of a low dielectric constant film is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-246494. Hereinafter, with reference to FIGS. 18A to 18C and FIGS. 19D and 19E, a method of manufacturing the same semiconductor device will be described in the order of steps. First, as shown in FIG. 18A, a gate oxide film 63 and a gate electrode (word line) 64 are formed in an active region surrounded by an isolation insulating film 62, and an N region forming a source region or a drain region is formed. After selectively forming the mold diffusion region 65, an interlayer insulating film 66 made of a silicon oxide film or the like is formed on the entire surface.
A mold silicon substrate 61 is prepared. Next, the interlayer insulating film 66 on the surface of the N-type diffusion region 65 is formed by photolithography.
After forming a contact hole 67, a polycrystalline silicon plug film 68 is formed on the entire surface by CVD.

Next, as shown in FIG.
A polycrystalline silicon film 69 serving as a main electrode of a lower electrode is formed on the entire surface by a method. Next, as shown in FIG. 18C, a titanium silicide film 70 is formed by a sputtering method, and subsequently, a tantalum nitride film 71 is formed by a reactive sputtering method.
Is formed. Next, as shown in FIG. 19D, a polycrystalline silicon plug film 68 is formed by photolithography.
By patterning the polycrystalline silicon film 69, the titanium silicide film 70, and the tantalum nitride film 71, the polycrystalline silicon film 69, the titanium silicide film 70, and the tantalum nitride film 71 are sequentially stacked on the polycrystalline silicon plug 68A. The lower electrode 73 is formed.

Next, after forming a tantalum oxide film 74 as a capacitance insulating film on the lower electrode 73 by the CVD method,
As shown in FIG. 19E, the tantalum oxide film 74 is patterned to remove unnecessary portions, and then an upper electrode 75 made of tungsten or the like is formed by a CVD method to complete the capacitance 76. According to the method of manufacturing a semiconductor device as described above, the tantalum nitride film 71 as a part of the lower electrode 73 is formed, and then the tantalum oxide film 74 as a capacitance insulating film is formed. Since the tantalum nitride film 71 functions as an oxidation suppressing film when the film 74 is formed, the oxidation of the lower electrode 73 can be suppressed. Therefore, the formation of the low dielectric constant film on the lower electrode can be suppressed.

[0015]

By the way, in the conventional method of manufacturing a semiconductor device described in the above-mentioned publication, the lower electrode is composed of a plurality of types of thin film materials, and a part of the lower electrode is used as an oxidation suppressing film. Therefore, there is a problem that the thin film forming process becomes complicated. That is, in the above publication, the lower electrode 73 is constituted by a laminate in which three types of thin films of a polycrystalline silicon film 69, a titanium silicide film 70, and a tantalum nitride film 71 are sequentially formed. Although a certain tantalum nitride film 71 is used as an oxidation suppressing film, formation of the lower electrode 73 requires the above-described three types of thin film forming steps.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and simplifies a thin film forming process so that the lower electrode can be prevented from being oxidized to form a low dielectric constant film. It is an object of the present invention to provide a method for manufacturing a semiconductor device and a method for manufacturing a capacitor.

[0017]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device having a capacitor formed to be connected to one diffusion region of a semiconductor substrate. A diffusion region forming step of selectively forming a second conductivity type diffusion region on a first conductivity type semiconductor substrate; and a lower electrode forming forming a lower electrode constituting the capacitor so as to be connected to the diffusion region. Forming a first insulating film having an oxygen deficiency on the lower electrode;
A film forming step, and a second step of reducing oxygen deficiency on the first insulating film.
A capacitor insulating film forming step of sequentially forming a capacitor insulating film constituting the capacitor, comprising a second film forming step of forming an insulating film; and a heat treatment of the semiconductor substrate in an oxidizing atmosphere to form the capacitor insulating film. (1) a semiconductor substrate heat treatment step of transforming at least a part of the insulating film into an insulating film having a small number of oxygen deficiencies so that the insulating film functions as an oxidation suppressing film for the lower electrode, and an upper part forming the capacitor on the capacitive insulating film And forming an upper electrode for forming an electrode.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first aspect, wherein the first film forming step and the second film forming step are alternately repeated.

According to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor device having a capacitor formed so as to be connected to one diffusion region of a semiconductor substrate. A diffusion region forming step of forming a two-conductivity type diffusion region, a lower electrode forming step of forming a lower electrode forming the capacitor so as to be connected to the diffusion region, and an oxygen forming the capacitor on the lower electrode A capacitor insulating film forming step of forming a capacitor insulating film formed of a defective insulating film; and heat treating the semiconductor substrate in an oxidizing atmosphere to transform a part of the insulating film into an insulating film with less oxygen vacancies. A semiconductor substrate heat treatment step of making the insulating film function as an oxidation suppressing film for the lower electrode; and an upper electrode forming step of forming an upper electrode constituting the capacitor on the capacitive insulating film. It is characterized in that it comprises and.

According to a fourth aspect of the present invention, there is provided the method of manufacturing a semiconductor device according to any one of the first to third aspects, wherein a metal oxide film is used as the capacitance insulating film.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the fourth aspect, wherein tantalum oxide is used as the metal oxide film.

According to a sixth aspect of the present invention, there is provided the method of manufacturing a semiconductor device according to any one of the first to fifth aspects, wherein the lower electrode and the upper electrode are made of titanium nitride, polycrystalline silicon, tungsten or tungsten nitride. It is characterized by using.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a capacitor for manufacturing a capacitor on a semiconductor substrate, wherein a lower electrode forming step of forming a lower electrode constituting the capacitor on the semiconductor substrate is provided. The capacitor comprising a first film forming step of forming a first insulating film having an oxygen vacancy on the first insulating film and a second film forming step of forming a second insulating film having a small amount of oxygen deficient on the first insulating film; A capacitor insulating film forming step of sequentially forming the constituent capacitor insulating films, and a heat treatment of the semiconductor substrate in an oxidizing atmosphere to transform at least a portion of the first insulating film into an insulating film having less oxygen deficiency. A semiconductor substrate heat treatment step of causing the insulating film to function as an oxidation suppressing film for the lower electrode; and an upper electrode forming step of forming an upper electrode constituting the capacitor on the capacitive insulating film. It is characterized.

According to an eighth aspect of the present invention, there is provided a method of manufacturing a capacitor according to the seventh aspect, wherein the first film forming step and the second film forming step are alternately repeated.

[0025]

According to a ninth aspect of the present invention, there is provided a method of manufacturing a capacitor according to the seventh or eighth aspect , wherein a metal oxide film is used as the capacitance insulating film.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a capacitor according to the ninth aspect , wherein the metal oxide film is
It is characterized by using tantalum oxide.

The invention of claim 11 wherein the claims 7 to 1
0 according to any one of the above items,
It is characterized in that titanium nitride, polycrystalline silicon, tungsten or tungsten nitride is used as the lower electrode and the upper electrode.

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

Embodiments of the present invention will be described below with reference to the drawings. The description will be made specifically using an embodiment. FIGS. 1A to 1C and FIGS. 2D to 2F are process diagrams showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps. Hereinafter, a method for manufacturing the same semiconductor device will be described in the order of steps with reference to FIGS. First,
As shown in FIG. 1A, for example, a P-type silicon substrate 1
After forming an element isolation insulating film 2 made of a silicon oxide film by a well-known LOCOS method, a silicon oxide film and a polycrystalline silicon film are sequentially formed in an active region surrounded by the element isolation insulating film 2. The silicon oxide film and the polycrystalline silicon film are patterned into desired shapes to form a gate oxide film 3 and a gate electrode (word line) 4. Next, by self-alignment using the gate oxide film 3 and the gate electrode 4 as a mask, an N-type impurity is introduced into the silicon substrate 1 by a known impurity introduction method such as an ion implantation method to form a source region or a drain region. After selectively forming the N-type diffusion region 5, an interlayer insulating film 6 made of a silicon oxide film or the like is formed on the entire surface.

Next, as shown in FIG. 1B, after forming a contact hole 7 in the interlayer insulating film 6 on the surface of the N-type diffusion region 5 by photolithography, the lower electrode film is entirely formed by sputtering. A titanium nitride film 8 having a thickness of 15 to 25 nm is formed.

Next, as shown in FIG. 1C, a film forming temperature of about 430 ° C. and a pressure of about 400 mTorr were obtained by CVD using tantalum pentaethoxy gas as a source gas.
After forming a first tantalum oxide (Ta ₂ O _x , X ≦ 4) film 9 having an oxygen deficiency with a film thickness of ₂ to 5 nm on the titanium nitride film 8 at a film formation pressure of r, Using tantalum pentaethoxy gas and oxygen gas as source gas,
At a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr, a second tantalum oxide (Ta ₂ O ₅ ) film 10 having a small thickness of _{2 to 5} nm and a small amount of oxygen is formed on the first tantalum oxide film 9. I do.

FIG. 3 is a diagram showing a film forming sequence for forming the first tantalum oxide film 9 and the second tantalum oxide film 10 described above. After accommodating the silicon substrate 1 in the reaction furnace of the CVD apparatus, at time t1, only the tantalum pentaethoxy gas as the source gas is supplied into the reaction furnace, and the formation of the first tantalum oxide film 9 is started. And
After the film forming process for a predetermined time T1 until time t2, time t1
In 2, a supply of oxygen gas to tantalum pentaethoxy gas as a source gas is supplied to start the formation of the second tantalum oxide film 10. After the film forming process for a predetermined time T2 until time t0, the supply of the tantalum pentaethoxy gas and the oxygen gas is stopped at time t0.

The first tantalum oxide film 9 having oxygen deficiency and the second tantalum oxide film 10 having little oxygen deficiency as described above
In each of the film forming methods, the first tantalum oxide film 9 was formed by using tantalum pentaethoxy gas in common as a source gas and supplying only tantalum pentaethoxy gas without supplying oxygen gas in the previous step. Thereafter, as a later stage, the second tantalum oxide film 10 is formed by adding and supplying an oxygen gas to tantalum pentaethoxy gas, so that the film can be easily formed only by switching the valve during the film formation process. be able to.

Next, the silicon substrate 1 is heat-treated (annealed) at about 500 ° C. for about 10 minutes in an atmosphere of UV-O ₃ . During this heat treatment, as shown in FIG. 2D, the surface of the titanium nitride
Is formed, the first tantalum oxide film 9 having oxygen deficiency reacts with oxygen and is transformed into a tantalum oxide film 9A having few oxygen deficiencies. In this case, the entire thickness of the first tantalum oxide film 9 having oxygen deficiency does not need to be changed to the tantalum oxide film 9A having small oxygen deficiency, and at least a part thereof may be changed. Since the above-mentioned tantalum oxide film 9A functions as an oxidation suppressing film for the titanium nitride film 8, thereafter, oxygen is blocked by the oxidation suppressing film and does not react with the titanium nitride film 8. Therefore, the titanium nitride film 8
Is suppressed, so that formation of a low dielectric constant film on the surface is suppressed. Although the above-described titanium oxide film 11 is an unnecessary film, a certain thickness is unavoidable, and 15 to 25% of the total thickness of the titanium nitride film 8 is formed. However, this value is extremely small as compared with the conventional example.

As described above, in this example, in order to form the oxidation suppressing film composed of the tantalum oxide film 9A, the first tantalum oxide film 9 having oxygen deficiency and the second tantalum oxide film 9 After the tantalum oxide film 10 is formed, it is only necessary to perform a heat treatment in a normal oxidizing atmosphere, so that the oxidation suppressing film can be easily formed without complicating the thin film forming process.

Next, as shown in FIG. 2E, the thickness of the upper electrode film is 15 to 25 n over the entire surface by sputtering.
m of titanium nitride film 12 is formed. Next, as shown in FIG. 2F, the lower electrode 8A and the upper electrode 12A are patterned by patterning the titanium nitride film 8, the tantalum oxide film 9A, the tantalum oxide film 10, and the titanium nitride film 12 by photolithography. To complete the capacitor 13 with the tantalum oxide films 10 and 9A interposed therebetween as a capacitive insulating film.

FIG. 8B shows the sheet resistance ρs of the lower electrode 8A obtained by the configuration of this example. The oxidation of the lower electrode 8A is suppressed, and the formation of the low dielectric constant film is suppressed, so that the value of the sheet resistance ρs is lower than that of the conventional example (A). Therefore, it is desirable as a lower electrode. In FIG. 9, (B) shows a silicon oxide film equivalent film thickness teq of the capacitor manufactured by the configuration of this example. Similarly to the sheet resistance ρs, the value is smaller than that of the conventional example (A), indicating that a predetermined capacitance can be obtained with a small-capacity insulating film.

As described above, according to the structure of this example, the first electrode having the oxygen deficiency on the lower electrode film composed of the titanium nitride film 8 is formed.
After sequentially forming the tantalum oxide film 9 and the second tantalum oxide film 10 with less oxygen deficiency, heat treatment is performed in an oxidizing atmosphere to transform the first tantalum oxide film 9 into a tantalum oxide film 9A with less oxygen deficiency. Since the tantalum oxide film 9A functions as an oxidation suppressing film for the lower electrode film, it is possible to prevent oxygen from reacting with the titanium nitride film 8 after the tantalum oxide film 9A is formed. Therefore, it is possible to simplify the thin film forming process and suppress the formation of the low dielectric constant film by oxidizing the lower electrode.

Second Embodiment FIGS. 4A to 4C are process diagrams showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps. The configuration of the method for manufacturing a semiconductor device of this example is significantly different from the configuration of the first embodiment described above in that a tantalum oxide film having an oxygen deficiency is formed in two stages. Hereinafter, a method for manufacturing the semiconductor device will be described in the order of steps with reference to FIG. First, as shown in FIG. 4A, CVD is performed using a silicon substrate 21 obtained by a process substantially similar to the process of FIG. 1B in the first embodiment.
Film forming temperature of about 430 ° C. and about 400 mTo
At a film forming pressure of rr, a first tantalum oxide (Ta ₂ O _x , X ≦ 4) film 19 having a thickness of 1 to 3 nm and having oxygen deficiency is formed on the titanium nitride film 8, and then a CVD method is used. Using tantalum pentaethoxy gas and oxygen gas as source gases, a second tantalum oxide (Ta ₂ O ₅₎ having a film thickness of 1 to 3 nm and having a small oxygen deficiency at a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr. ) The film 20 is replaced with the first tantalum oxide film 1
9 is formed.

Next, as shown in FIG. 4 (b), a film forming temperature of about 430 ° C. and a film forming temperature of about 400 mTorr using a tantalum pentaethoxy gas as a source gas by a CVD method.
At a film formation pressure of r, a third tantalum oxide (Ta ₂ O _x , X ≦ 4) film 21 having an oxygen deficiency with a film thickness of 1 to 3 nm is formed on the second tantalum oxide film 20.

FIG. 5 shows the first tantalum oxide film 19 described above.
FIG. 3 is a diagram showing a film forming sequence for forming a second tantalum oxide film 20 and a third tantalum oxide film 21. CVD
After accommodating the silicon substrate 21 in the reaction furnace of the apparatus, at time t1, only the tantalum pentaethoxy gas as the source gas is supplied into the reaction furnace, and the first tantalum oxide film 1
9 is started. Then, after the film forming process for a predetermined time T1 until time t2, at time t2, a tantalum pentaethoxy gas is supplied as a source gas so as to add an oxygen gas, and the film formation of the second tantalum oxide film 20 is started. Then, after the film forming process for a predetermined time T2 until time t3, at time t3, only the tantalum pentaethoxy gas is supplied again as the source gas to start forming the third tantalum oxide film 21. After the film forming process for a predetermined time T3 until time t0, the supply of tantalum pentaethoxy gas is stopped at time t0.

Next, the silicon substrate 21 is heat-treated at about 500 ° C. for about 10 minutes in an atmosphere of UV-O ₃ . During this heat treatment, as shown in FIG. 4C, the surface of the titanium nitride film 8 is oxidized to form the titanium oxide film 11, and at the same time, the first tantalum oxide film 19 having oxygen deficiency and the third
The tantalum oxide film 21 reacts with oxygen and is transformed into tantalum oxide films 19A and 21A each having less oxygen deficiency. In this case, as in the case of the first embodiment, the first tantalum oxide film 19 and the third tantalum oxide film
No. 1 does not need to be transformed into the tantalum oxide films 19A and 21A having a small total oxygen deficiency, and may be transformed at least partially.

Since the above-described tantalum oxide film 19A and tantalum oxide film 21A function as an oxidation suppressing film for the titanium nitride film 8, oxygen is thereafter prevented by the oxidation suppressing film and does not react with the titanium nitride film 8. Therefore, the oxidation of the titanium nitride film 8 is suppressed, and the formation of a low dielectric constant film on the surface is suppressed. According to the configuration of this example, since both the tantalum oxide film 19A and the tantalum oxide film 21A are used as the oxidation suppressing film as compared with the first embodiment, the function as the oxidation suppressing film is improved. Can be. Next, a capacitor is completed through substantially the same steps as those shown in FIG. 2E and subsequent steps in the first embodiment. Other than this, it is substantially the same as the first embodiment described above. Therefore, in FIG. 4, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

FIG. 8C shows the sheet resistance ρs of the lower electrode 8A obtained by the configuration of this example. The oxidation of the lower electrode 8A is further suppressed, and the formation of the low dielectric constant film is further suppressed, so that the value of the sheet resistance ρs is lower than the result (B) of the first embodiment.
Therefore, it is desirable as a lower electrode. FIG.
In (C), the equivalent silicon oxide film thickness teq of the capacitor manufactured by the configuration of this example is shown.
Similarly to the sheet resistance ρs, the value is smaller than the result (B) according to the first embodiment, indicating that a predetermined capacitance can be obtained with a small-capacity insulating film.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained. In addition, according to the configuration of this example, the number of layers of the oxidation suppressing film is increased, so that the function as the oxidation suppressing film can be enhanced.

Third Embodiment FIGS. 6A to 6C are process diagrams showing a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps. The configuration of the method of manufacturing the semiconductor device of this example is significantly different from the configuration of the second embodiment described above in that a tantalum oxide film having an oxygen deficiency is formed in three stages. Hereinafter, a method for manufacturing the same semiconductor device will be described in the order of steps with reference to FIG. First, as shown in FIG. 6A, CVD is performed using a silicon substrate 31 obtained by a process substantially similar to the process of FIG. 1B in the first embodiment.
Film forming temperature of about 430 ° C. and about 400 mTo
After forming a first tantalum oxide (Ta ₂ O _x , X ≦ 4) film 25 having an oxygen deficiency with a film thickness of 1 to 3 nm on the titanium nitride film 8 at a film forming pressure of rr, the film is formed by CVD. Using tantalum pentaethoxy gas and oxygen gas as source gases, a second tantalum oxide (Ta ₂ O ₅₎ having a film thickness of 1 to 3 nm and having a small oxygen deficiency at a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr. ) The film 26 is changed to the first tantalum oxide film 2
5 and then using a tantalum pentaethoxy gas as a source gas at a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr to form an oxygen deficiency film having a film thickness of 1 to 3 nm. Tertiary tantalum oxide (Ta ₂
O _x , X ≦ 4) A film 27 is formed on the second tantalum oxide film 26.

Next, as shown in FIG. 6B, a film forming temperature of about 430 ° C. and a temperature of about 4 ° C. were obtained by CVD using tantalum pentaethoxy gas and oxygen gas as source gases.
At a film formation pressure of 00 mTorr, a fourth tantalum oxide (Ta ₂ O ₅ ) film 28 having a small thickness of 1 to 3 nm and having a small oxygen deficiency is formed on the third tantalum oxide film 27, and then a CVD method is used. Using tantalum pentaethoxy gas as a source gas, at a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr, a fifth tantalum oxide (Ta ₂ O _X , X ≦ 1) having a thickness of 1 to 3 nm and having an oxygen deficiency. 4) A film 29 is formed on the fourth tantalum oxide film 28, and then a film forming temperature of about 430 ° C. and about 400 mTorr by CVD using tantalum pentaethoxy gas and oxygen gas as source gases.
The sixth tantalum oxide (Ta ₂ O ₅ ) film 30 having a small thickness of 1 to 3 nm and having a small oxygen deficiency is formed on the fifth tantalum oxide film 29 at the film forming pressure.

FIG. 7 shows the first tantalum oxide film 25 described above.
FIG. 4 is a diagram showing a film forming sequence of a second tantalum oxide film 26, a third tantalum oxide film 27, a fourth tantalum oxide film 28, a fifth tantalum oxide film 29, and a sixth tantalum oxide film 30. After accommodating the silicon substrate 31 in the reaction furnace of the CVD apparatus, at time t1, only the tantalum pentaethoxy gas, which is the source gas, is supplied into the reaction furnace to start the formation of the first tantalum oxide film 25. Then, after the film forming process for a predetermined time T1 up to time t2, at time t2, supply is performed so that oxygen gas is added to tantalum pentaethoxy gas as a source gas, and film formation of the second tantalum oxide film 26 is started. Then, a predetermined time T2 until time t3
After the film formation processing, at time t3, only the tantalum pentaethoxy gas is supplied again as the source gas, and the formation of the third tantalum oxide film 27 is started. And time t
After the film forming process for a predetermined time T3 up to T4, supply the tantalum pentaethoxy gas to the fourth tantalum oxide film 2 at time t4 so that oxygen gas is added to tantalum pentaethoxy gas.
8 is started. After a predetermined time T4 of film formation processing until time t5, only tantalum pentaethoxy gas is again supplied as a source gas at time t5,
The formation of the fifth tantalum oxide film 29 is started. After the film forming process for a predetermined time T5 until time t6, at time t6
Then, a tantalum pentaethoxy gas and an oxygen gas are supplied as source gases, and the formation of the sixth tantalum oxide film 30 is started. Then, a predetermined time T6 until time t0
After the film forming process, supply of tantalum pentaethoxy gas and oxygen gas is stopped at time t0.

Next, the silicon substrate 31 is heat-treated at about 500 ° C. for about 10 minutes in an atmosphere of UV-O ₃ . At the time of this heat treatment, as shown in FIG. 6C, the surface of the titanium nitride film 8 is oxidized to form the titanium oxide film 11, and at the same time, the first tantalum oxide film 25 having oxygen vacancies has less oxygen vacancies. The tantalum oxide (Ta ₂ O ₅ ) film 25A has a third tantalum oxide film 27 having an oxygen deficiency, the tantalum oxide (Ta ₂ O ₅ ) film 27A has a small oxygen deficiency, and the fifth tantalum oxide film 29 has an oxygen deficiency. It is transformed into a tantalum oxide (Ta ₂ O ₅ ) film 29A with little oxygen deficiency. And since the above-mentioned tantalum oxide film 25A, tantalum oxide film 27A, and tantalum oxide film 29A function as an oxidation suppression film,
Thereafter, oxygen is blocked by the oxidation suppressing film and the titanium nitride film 8 is formed.
Does not respond to Therefore, formation of a low dielectric constant film on the surface of the titanium nitride film 8 is suppressed. According to the configuration of this example, the function as an oxidation suppressing film can be enhanced in substantially the same manner as in the second embodiment. Next, FIG.
(E) The capacitor is completed through substantially the same steps as the following steps.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the second embodiment can be obtained. In addition, according to the configuration of this example, the number of layers of the oxidation suppressing film is further increased, so that the function as the oxidation suppressing film can be further enhanced.

Fourth Embodiment In the method of manufacturing a semiconductor device of this embodiment, a capacitor is formed by using a polycrystalline silicon film instead of the titanium nitride film 8 as the lower electrode film in the first embodiment. In this example, the heat treatment of the silicon substrate 1 is performed by oxygen plasma,
This is performed at about 800 ° C. for about 10 minutes in an oxidizing atmosphere such as Dry-O ₂ . Except for this, the processes in the respective steps are performed under substantially the same conditions as in the above-described first embodiment to complete the capacitor. Therefore, description of other processing conditions is omitted. In FIG. 10, (B) shows a silicon oxide film equivalent film thickness teq of the capacitor manufactured by the configuration of this example. This value is smaller than that of the conventional example (A), and indicates that a predetermined capacitance can be obtained with a small-capacity insulating film.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the first embodiment can be obtained.

Fifth Embodiment In the method of manufacturing a semiconductor device of this embodiment, a capacitor is formed by using a polycrystalline silicon film instead of the titanium nitride film 8 as the lower electrode film in the second embodiment. In this example, the heat treatment of the silicon substrate 1 is performed by oxygen plasma,
This is performed at about 800 ° C. for about 10 minutes in an oxidizing atmosphere such as Dry-O ₂ . Except for this, each process is performed under substantially the same conditions as in the above-described second embodiment to complete the capacitor.
Therefore, description of other processing conditions is omitted. In FIG. 10, (C) shows a silicon oxide film equivalent film thickness teq of the capacitor manufactured by the configuration of this example. The value is smaller than that of the fourth embodiment (B), which indicates that a predetermined capacitance can be obtained with a small-capacity insulating film.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the second embodiment can be obtained.

Sixth Embodiment In the method of manufacturing a semiconductor device of this embodiment, a capacitor is formed by using a polycrystalline silicon film instead of the titanium nitride film 8 as the lower electrode film in the third embodiment. In this example, the heat treatment of the silicon substrate 1 is performed by oxygen plasma,
This is performed at about 800 ° C. for about 10 minutes in an oxidizing atmosphere such as Dry-O ₂ . Except for this, each process is performed under substantially the same conditions as in the third embodiment described above to complete the capacitor.
Therefore, description of other processing conditions is omitted.

As described above, according to the structure of this embodiment, substantially the same effects as those described in the third embodiment can be obtained.

Seventh Embodiment FIGS. 11A and 11B are process diagrams showing a method of manufacturing a semiconductor device according to a seventh embodiment of the present invention in the order of steps. The configuration of the manufacturing method of the semiconductor device of this example is significantly different from the configuration of the first embodiment described above in that a tantalum oxide film having oxygen deficiency is formed in one step.
Hereinafter, a method for manufacturing the same semiconductor device will be described in the order of steps with reference to FIG. First, FIG. 1 in the first embodiment
Silicon substrate 4 obtained by a process substantially similar to the process of (b)
As shown in FIG. 11 (a), using tantalum pentaethoxy gas as a source gas at a film forming temperature of about 430 ° C. and a film forming pressure of about 400 mTorr, the film thickness is substantially reduced. A 10 nm oxygen-deficient tantalum oxide (Ta ₂ O _x , X ≦ 4) film 31 is formed on the titanium nitride film 8.

Next, the silicon substrate 41 is heat-treated in a UV-O ₃ atmosphere at about 500 ° C. for about 10 minutes. During this heat treatment, as shown in FIG. 11B, the surface of the titanium nitride film 8 is oxidized to form the titanium oxide film 11, and at the same time, the tantalum oxide film 31 having oxygen deficiency reacts with oxygen to form the titanium oxide film 31. Approximately 8 nm is oxidized from the surface and is transformed into a tantalum oxide film 31A having few oxygen vacancies. in this case,
The total thickness of the tantalum oxide film 31 having oxygen deficiency may be changed to the tantalum oxide film 31A having small oxygen deficiency. Since the thickness of the titanium oxide film 11 formed on the surface of the titanium nitride film 8 serving as the lower electrode is increased, a low dielectric constant film is formed, which is not preferable.

The above-mentioned tantalum oxide film 31A is
Since it functions as an oxidation suppressing film for the titanium nitride film 8, oxygen is thereafter blocked by the oxidation suppressing film and does not react with the titanium nitride film 8. Therefore, the oxidation of the titanium nitride film 8 is suppressed, and the formation of a low dielectric constant film on the surface is suppressed. Next, a capacitor is completed through substantially the same steps as those shown in FIG. 2E and subsequent steps in the first embodiment. Other than this, it is substantially the same as the first embodiment described above. Therefore, in FIG. 11, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 12 shows the thickness (vertical axis) of the capacitance insulating film of the capacitor obtained by the method of manufacturing a semiconductor device according to this embodiment, in which the tantalum oxide film having oxygen deficiency has been changed to a tantalum oxide film having less oxygen deficiency. and a diagram showing the relationship between UV-O ₃ heat treatment temperature (horizontal axis) shows the UV-O ₃ thermal treatment temperature dependence of the film thickness varies less tantalum oxide film with oxygen vacancies. As is clear from the figure, the higher the heat treatment temperature, the thicker the above-mentioned film thickness, which indicates that a high-quality tantalum oxide film can be obtained as the oxidation suppressing film.

FIG. 13 is a diagram showing the relationship between the equivalent silicon oxide film thickness teq and the oxidation progress thickness of the capacitor insulating film of the capacitor obtained by the method of manufacturing a semiconductor device of this example. Here, the oxidation progress film thickness of 0 nm indicates that the tantalum oxide film is a film having oxygen deficiency over the entire film thickness, and the oxidation progress film thickness of 10 nm indicates that the tantalum oxide film having the oxygen deficiency is The figure shows a case where the film is changed into a film having less oxygen deficiency over the entire film thickness. The oxidation progress thickness of 15 nm means that the titanium oxide film 11 having a thickness of about 5 nm is formed on the surface of the titanium nitride film 8 as the lower electrode.
The case where the thickness of 5 nm is added to the thickness of the above-described 10 nm tantalum oxide film is shown. As is clear from the figure, when the tantalum oxide film having an oxygen deficiency having a thickness of about 10 nm is transformed into a film having a small number of oxygen deficiencies over the entire film thickness, the teq becomes the smallest and the capacitance insulating film becomes excellent. It has become.

FIG. 14 is a diagram showing the relationship between the leakage current and the oxidized film thickness of the capacitor insulating film of the capacitor obtained by the method of manufacturing a semiconductor device of this example. As is clear from the figure, the leak current tends to increase as the thickness of the tantalum oxide film having oxygen deficiency increases. However, even if the tantalum oxide film having less oxygen deficiency is not necessarily formed to a thickness of 10 nm, the leakage current becomes approximately 5 nm or more. When the film thickness is formed in such a manner as described above, the leak current can be reduced to such an extent that it does not substantially interfere.

As described above, according to the structure of this embodiment, substantially the same effects as described in the first embodiment can be obtained. In addition, according to the configuration of this example, only the tantalum oxide film having oxygen deficiency is formed in a single layer, and then heat-treated in an oxidizing atmosphere to be transformed into a tantalum oxide film having less oxygen deficiency. Can be made easier.

Eighth Embodiment In the method for manufacturing a semiconductor device of this embodiment, heat treatment is performed in a dry atmosphere using an electric furnace (furnace) instead of the heat treatment in an atmosphere of UV-O ₃ in the seventh embodiment. That is, as in the first embodiment, a tantalum oxide (Ta ₂ O _X , X
≦ 4) After forming the film 31, heat treatment is performed at 500 to 800 ° C. in a dry atmosphere of the furnace. Except for this, each process is performed under substantially the same conditions as in the above-described seventh embodiment to complete the capacitance. Therefore, description of other processing conditions is omitted.

FIG. 15 shows the thickness (in the vertical axis and the vertical axis) of the capacitance insulating film of the capacitor obtained by the method of manufacturing the semiconductor device according to this embodiment, in which the tantalum oxide film having oxygen deficiency is changed to a tantalum oxide film having few oxygen deficiencies. ) And the furnace heat treatment temperature (horizontal axis), showing the furnace heat treatment temperature dependency of the film thickness changing to a tantalum oxide film with less oxygen deficiency. As is apparent from FIG.
As in the case of No. 2, the higher the heat treatment temperature, the thicker the thickness of the tantalum oxide film with less oxygen deficiency, indicating that a high-quality tantalum oxide film can be obtained as the oxidation suppressing film.

As described above, according to the structure of this embodiment, substantially the same effects as described in the seventh embodiment can be obtained.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there may be changes in the design without departing from the gist of the present invention. Is also included in the present invention. For example, the method of forming the oxygen-deficient film serving as the oxidation suppression film is not limited to the method of switching the supply of the oxygen gas to the source gas, but may be performed by a method of controlling the flow ratio of the source gas and the oxygen gas. Can be. Further, an insulating film with few oxygen vacancies formed by heat treatment of an insulating film with oxygen vacancies and an insulating film with few oxygen vacancies formed from the beginning have the composition (Ta
_{In 2} O _X ), X may be different.

The lower electrode is not limited to titanium nitride and polycrystalline silicon, but may be other conductive materials such as tungsten or tungsten nitride. Also,
The conductive material for the upper electrode is not limited to the conductive material for the lower electrode, and any of the conductive materials described above can be used. The capacitance insulating film is not limited to tantalum oxide, but may be BST (BaSr) TiO ₃ , P
Other high dielectric films such as ZT (Pb (ZrTi) O ₃ can be used.

Further, as long as a capacitor is manufactured on a semiconductor substrate, the present invention can be applied not only to a DRAM but also to a case of manufacturing a capacitor alone. In addition, the thickness of each conductive film, insulating film, and the like, the method of forming the film, and the like are merely examples, and can be changed depending on the application, purpose, and the like. The gate oxide film is an oxide film (Oxide Film).
However, the present invention is not limited thereto, and a nitride film (Nitride Film) may be used, or a double film structure of an oxide film and a nitride film may be used. That is,
MNS (Metal Nitride Semiconductor)
Type transistor or MNOS (Metal
Nitride Oxide Semiconductor) type transistors may be used. Also, the conductivity type of each semiconductor region can be reversed between P-type and N-type. That is, not only N-channel type
The invention can also be applied to a channel type MIS transistor.

[0076]

As described above, according to the method of manufacturing a semiconductor device and the method of manufacturing a capacitor of the present invention, a capacitor insulating film having oxygen vacancies and a capacitor insulating film having few oxygen vacancies are sequentially formed on a lower electrode film. After the film is formed, heat treatment is performed in an oxidizing atmosphere to transform at least a part of the capacity insulating film having oxygen vacancies into a capacity insulating film having few oxygen vacancies. Since it functions as an oxidation suppressing film, it is possible to prevent oxygen from reacting with the lower electrode film after the lower electrode film is formed. Further, according to the method for manufacturing a semiconductor device and the method for manufacturing a capacitor of the present invention, after a capacitor insulating film having oxygen deficiency is formed on the lower electrode film, heat treatment is performed in an oxidizing atmosphere to remove oxygen deficiency. Since at least a part of the capacitor insulating film is transformed into a capacitor insulating film with less oxygen deficiency and the capacitor insulating film with less oxygen deficiency is made to function as an oxidation suppressing film for the lower electrode film, after the lower electrode film is formed, Oxygen can be prevented from reacting with the lower electrode film. Therefore, it is possible to simplify the thin film forming process and suppress the formation of the low dielectric constant film by oxidizing the lower electrode.

[Brief description of the drawings]

FIG. 1 is a process chart showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a process chart showing a method for manufacturing the semiconductor device in the order of steps.

FIG. 3 is a view showing a sequence of forming a capacitance insulating film in the method of manufacturing the semiconductor device.

FIG. 4 is a process chart showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

FIG. 5 is a view showing a sequence of forming a capacitance insulating film in the method of manufacturing the semiconductor device.

FIG. 6 is a process chart showing a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps.

FIG. 7 is a view showing a sequence of forming a capacitive insulating film in the method of manufacturing the semiconductor device.

FIG. 8 is a diagram showing the sheet resistance of the lower electrode of the capacitor obtained by the method for manufacturing the semiconductor device in comparison with the conventional example.

FIG. 9 is a view showing a silicon oxide film equivalent thickness of a capacitor insulating film of a capacitor obtained by the method of manufacturing the semiconductor device in comparison with a conventional example.

FIG. 10 is a diagram showing the equivalent silicon oxide film thickness of a capacitor insulating film of a capacitor obtained by the method of manufacturing the semiconductor device in comparison with a conventional example.

FIG. 11 is a process chart showing a method of manufacturing a semiconductor device according to a seventh embodiment of the present invention in the order of steps.

FIG. 12 is a graph showing the heat treatment temperature dependence of the thickness of a capacitor insulating film of a capacitor obtained by the same method for manufacturing a semiconductor device in which a tantalum oxide film having oxygen vacancies is changed to a tantalum oxide film having few oxygen vacancies. is there.

FIG. 13 is a diagram showing a relationship between a silicon oxide film equivalent film thickness of a capacitor insulating film of a capacitor obtained by the same method of manufacturing the semiconductor device and an oxidation progress film thickness.

FIG. 14 is a view showing a relationship between a leakage current of a capacitance insulating film of a capacitor and an oxidation progressed film thickness obtained by the same method for manufacturing a semiconductor device.

FIG. 15 is a graph showing the heat treatment temperature dependence of the thickness of the capacitor insulating film of the capacitor obtained by the method of manufacturing the semiconductor device, in which the tantalum oxide film having oxygen deficiency has been changed to a tantalum oxide film having less oxygen deficiency. is there.

FIG. 16 is a process chart showing a conventional method of manufacturing a semiconductor device in the order of steps.

FIG. 17 is a process chart showing a conventional method of manufacturing a semiconductor device in the order of steps.

FIG. 18 is a process chart showing a conventional method of manufacturing a semiconductor device in the order of steps.

FIG. 19 is a process chart showing a conventional method of manufacturing a semiconductor device in the order of steps.

FIG. 20 is a view showing a film forming sequence of a capacitive insulating film in the method of manufacturing the semiconductor device.

[Explanation of symbols]

1, 21, 31, 41 P-type silicon substrate 2 Element isolation insulating film 3 Gate oxide film 4 Gate electrode (word line) 5 N-type diffusion region 6 Interlayer insulating film 7 Contact hole 8 Titanium nitride film (lower electrode film) 8A Lower electrode 9, 19, 25 First tantalum oxide film (with oxygen deficiency) 9A, 19A, 21A, 25A, 27A, 29A, 31
A Tantalum oxide film (less oxygen deficiency) 10, 20, 26 Second tantalum oxide film (less oxygen deficiency) 11 Titanium oxide film 12 Titanium nitride film (upper electrode film) 12A Upper electrode 21, 27 Third tantalum oxide film (oxygen Defect) 28 Fourth tantalum oxide film (less oxygen deficiency) 29 Fifth tantalum oxide film (with oxygen deficiency) 30 Sixth tantalum oxide film (less oxygen deficiency) 31 Tantalum oxide film (less oxygen deficiency)

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/8242 H01L 21/822 H01L 27/04 H01L 27/108

Claims (11)

(57) [Claims] 1. A method for manufacturing a semiconductor device comprising a capacitor formed to be connected to one diffusion region of a semiconductor substrate, wherein the first conductivity type semiconductor substrate has a second conductivity type diffusion region selectively. Forming a lower electrode forming the capacitor so as to be connected to the diffusion region; forming a first insulating film having oxygen deficiency on the lower electrode And a second film forming step of forming a second insulating film with less oxygen deficiency on the first insulating film. Forming an insulating film; and subjecting the semiconductor substrate to a heat treatment in an oxidizing atmosphere.
A semiconductor substrate heat treatment step of transforming at least a part of the insulating film into an insulating film having a small number of oxygen deficiencies, so that the insulating film functions as an oxidation suppressing film for the lower electrode; and an upper electrode forming the capacitor on the capacitive insulating film A method of manufacturing a semiconductor device, comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein said first film forming step and said second film forming step are alternately repeated. 3. A method of manufacturing a semiconductor device comprising a capacitor formed to be connected to one diffusion region of a semiconductor substrate, wherein the first conductivity type semiconductor substrate is selectively formed in a second conductivity type diffusion region. Forming a lower electrode forming the capacitor so as to be connected to the diffusion region; forming an insulating film having an oxygen deficiency forming the capacitor on the lower electrode A capacitor insulating film forming step of forming a capacitor insulating film consisting of: heat treating the semiconductor substrate in an oxidizing atmosphere to partially transform the insulating film into an insulating film having less oxygen deficiency; A semiconductor substrate heat treatment step of functioning as an oxidation suppressing film for the lower electrode; and an upper electrode forming step of forming an upper electrode constituting the capacitor on the capacitance insulating film. The method of manufacturing a semiconductor device according to symptoms. 4. The method for manufacturing a semiconductor device according to claim 1, wherein a metal oxide film is used as said capacitance insulating film. 5. The method according to claim 4, wherein tantalum oxide is used as said metal oxide film. 6. The method according to claim 1, wherein the lower electrode and the upper electrode are made of titanium nitride, polycrystalline silicon, tungsten, or tungsten nitride. 7. A method for manufacturing a capacitor for manufacturing a capacitor on a semiconductor substrate, comprising: a lower electrode forming step of forming a lower electrode constituting the capacitor on the semiconductor substrate; A capacitor insulating film constituting the capacitor, comprising: a first film forming step of forming a first insulating film; and a second film forming step of forming a second insulating film having less oxygen deficiency on the first insulating film. Forming a capacitor insulating film, and forming a first film by heat-treating the semiconductor substrate in an oxidizing atmosphere.
A semiconductor substrate heat treatment step of transforming at least a part of the insulating film into an insulating film having a small number of oxygen deficiencies, so that the insulating film functions as an oxidation suppressing film for the lower electrode; and an upper electrode forming the capacitor on the capacitive insulating film And forming an upper electrode. 8. The method according to claim 7, wherein the first film forming step and the second film forming step are alternately repeated. As claimed in claim 9, wherein the capacitor insulating film, a manufacturing method according to claim 7 or 8, wherein the capacitor is characterized by using a metal oxide film. 10. The method according to claim 9 , wherein tantalum oxide is used as the metal oxide film. As claimed in claim 11, wherein the lower electrode and the upper electrode, titanium nitride, polycrystalline silicon, method of manufacturing a capacitor according to any one of claims 7 to 10, wherein the use of tungsten or tungsten nitride.