JP2009129963A - Film formation method, film-forming apparatus, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film formation method and a film-forming apparatus capable of efficiently removing an organic solvent constituent in source gas and suppressing the decomposition of an organic metal compound included in the source gas. <P>SOLUTION: The film formation method includes: a process for generating the source gas by vaporizing a solution where the metal organic compound is dissolved into an organic medium; and a process for introducing the source gas into a reaction chamber 10 with a substrate 1 placed therein. Before the source gas reaches the substrate 1, a catalyst including a noble metal is brought into contact with the source gas and oxygen gas, the organic solvent is decomposed, and a film 2 including metal is formed on the substrate 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a film forming method, a film forming apparatus, and a method for manufacturing a semiconductor device, and in particular, a film forming method using a liquid raw material in which an organometallic compound is dissolved in an organic solvent, and a composition for performing the film forming method. The present invention relates to a film device and a method for manufacturing a semiconductor device having a dielectric film.

  In a ferroelectric memory device, with the demand for further higher integration, the miniaturization of a ferroelectric capacitor having a large occupation ratio in a chip is progressing. A problem in the capacitor manufacturing technology related to miniaturization is to secure a sufficiently large capacitor capacity.

For example, lead zirconate titanate (PZT: Pb (Zr, Ti) O ₃ ) is used as the ferroelectric film constituting the ferroelectric capacitor, and the PZT film is formed by sputtering, sol-gel method, vapor phase growth ( The CVD (Chemical Vapor Deposition) method and the like are known.

  Among these film forming methods, a CVD method capable of reducing the thickness of the PZT film is used in order to secure a necessary capacitor capacity. There are two types of CVD methods depending on the raw material supply method.

  The first method is a method in which an organometallic compound that is solid at room temperature is heated and sublimated in a raw material container, and the sublimated organometallic compound is conveyed to a film forming chamber by a carrier gas. The second method is a method in which an organometallic compound that is solid at room temperature is dissolved in an organic solvent to form a liquid raw material, which is vaporized by a vaporizer and conveyed to a film formation chamber.

The first method is performed by a film forming apparatus as shown in FIG. 10, for example.
A plurality of raw material containers 105 a to 105 c are connected to a film forming chamber 101 of the CVD apparatus shown in FIG. 10 through gas pipes 103 and 103 a to 103 c heated by a heater 102 and a gas mixer 104. In addition, carrier gas pipes 107a to 107c are connected to the raw material containers 105a to 105c via mass flow controllers 106a to 106c, respectively. The gas transfer system devices such as the mass flow controllers 106a to 106c and the raw material containers 105a to 105c are surrounded by the constant temperature baths 108a and 108b and heated to a predetermined temperature.

  An organometallic compound is used as the raw materials 109a to 109c filled in the raw material containers 105a to 105c. And as shown to FIG. 11A, the raw material 109a (109b, 109c) is filled in the area | region enclosed by the mesh board 110a, 110b up and down within the raw material container 105a (105b, 105c).

  The gas supply system apparatus including the raw material containers 105a to 105c and the carrier gas pipes 107a to 107c is heated to a temperature equal to or higher than the sublimation temperature of the organometallic compound by the constant temperature baths 108a and 108b and the heater 102, for example, 250 ° C.

Thus, the organometallic compound sublimated in the raw material containers 105a to 105c is introduced into the shower head 111 in the film forming chamber 101 together with the carrier gas. The flow rate of the carrier gas is controlled by the mass flow controllers 106a to 106c.
For example, JP-A-2001-342566 (Patent Document 1) describes a method of sublimating an organometallic compound filled in a raw material container in a thermostatic bath and supplying the substrate to a substrate.

  Each organometallic compound introduced into the shower head 111 flies to the substrate 113 heated by the heater 112. Each organometallic compound supplied to the substrate 113 forms a PZT film on the substrate 113 by a reaction with an oxidizing agent introduced in the middle of the gas pipe 103. The temperature of the substrate 113 is controlled by the heater 112 so as to be within a temperature range of 450 ° C. to 600 ° C.

Note that an automatic pressure controller 115 is attached to the exhaust pipe 114 attached to the film formation chamber 101, and the automatic pressure controller 115 is based on the measurement data of the pressure gauge 116 connected to the film formation chamber 101. Control the exhaust flow rate.
In FIG. 10, reference numerals 107a to 107m and 118 denote valves.

  According to the film forming method using the film forming apparatus shown in FIG. 10, a raw material supply method is adopted in which the organometallic compounds 109a to 109c are sublimated in the raw material containers 105a to 105c and transferred to the film forming chamber 101 together with the carrier gas. ing.

  According to this raw material supply method, as the time for sublimating the organometallic compound in the raw material containers 105a to 105c has elapsed, the organometallic compounds 109a to 109c in a fine powder state in the initial state aggregate to form the state shown in FIG. Become. In the organic metal compounds 109a to 109c in which aggregation occurs, the total surface area is reduced and the sublimation amount is reduced, the contact area with the carrier gas is also reduced, and the supply amount of the organometallic compound gas is reduced.

Such agglomeration is noticeable in the organometallic compound for supplying Zr when forming PZT. This is because Zr (DPM) ₄ has a lower vapor pressure than Pb (DPM) ₂ and Ti (OiPr) ₂ (DPM) ₂ which are other organometallic compounds.
As a result, the concentration of Zr supplied to the film forming chamber is likely to change with the passage of time of use, which causes the quality of the PZT film to deteriorate.

  On the other hand, a film forming apparatus for carrying out the second method is not particularly shown, but a liquid raw material in which an organometallic compound is dissolved in an organic solvent is vaporized by a vaporizer, and the vaporized raw material is formed through a gas pipe. It is configured to supply to the chamber. In the raw material container filled with such a liquid raw material, the aggregation of the organometallic compound is hardly a problem.

  However, when a source gas obtained by vaporizing an organometallic compound containing an organic solvent is supplied onto the substrate to form a PZT film, the influence of the organic solvent on the film quality cannot be ignored.

  As a method for removing the organic solvent, Japanese Patent Laid-Open No. 2002-305194 (Patent Document 2) discloses that a combustion chamber is provided in the middle of a gas pipe for supplying a raw material gas to a film forming chamber, and an oxidizing agent is added to the combustion chamber. It is described that the raw material gas is introduced and preheated at 320 ° C. or higher. Thus, Patent Document 2 describes that the supply of the organic solvent to the substrate can be suppressed.

In addition, JP 2004-335607 A (Patent Document 3) discloses that a catalyst of rhodium or a noble metal containing rhodium as a main component is used before adding oxygen to a raw material gas for forming PZT, SBT or the like. It is described that a catalyst thermal decomposition means for thermally decomposing a solvent component is provided on the upstream side of a film forming chamber.
JP 2001-342666 A JP 2002-305194 A JP 2004-335607 A

However, according to the method for removing an organic solvent described in Patent Document 2, since the organometallic compound contained in the source gas is also heated at 320 ° C. or higher at the same time, the organometallic compound is decomposed before reaching the substrate. There is a fear.
Further, Patent Document 3 does not specifically describe the temperature or the like for the thermal decomposition of the organic solvent component, but only describes that it can be decomposed at a low temperature.

  An object of the present invention is to provide a film forming method, a film forming apparatus, and a semiconductor device manufacturing method capable of efficiently removing an organic solvent component in a source gas.

According to one aspect of the present invention, a step of generating a raw material gas by vaporizing a solution in which a metal organic compound is dissolved in an organic solvent, and a step of introducing the raw material gas into a reaction chamber in which a substrate is installed. And before the source gas reaches the substrate, the catalyst containing the noble metal, the source gas, and the oxygen gas are brought into contact with each other, the organic solvent is decomposed, and a film containing the metal is formed on the substrate. A featured deposition method is provided.
According to another aspect of the present invention, a reaction chamber in which a substrate is installed, a vaporizer that generates a raw material gas by vaporizing a solution obtained by dissolving a metal organic compound in an organic solvent, and a raw material gas generated by the vaporizer Solvent decomposition that decomposes the organic solvent by bringing the oxygen gas supply unit that supplies oxygen gas into the reaction chamber, the organic solvent in the raw material gas, the catalyst containing the oxygen gas, and the noble metal in contact with each other A film forming apparatus characterized in that the film forming apparatus is provided.
According to another aspect of the present invention, a step of forming a lower electrode above a semiconductor substrate, a step of forming a dielectric film on the lower electrode, and a step of forming an upper electrode on the dielectric film, And forming the dielectric film includes a step of generating a source gas by vaporizing a solution in which a metal organic compound is dissolved in an organic solvent, and supplying the source gas to the semiconductor substrate on which the lower electrode is formed. Before reaching the semiconductor substrate on which the lower electrode is formed, a catalyst containing a noble metal, a source gas, and an oxygen gas are brought into contact with each other to decompose an organic solvent and deposit a dielectric film. A manufacturing method is provided.

  According to the present invention, the organic solvent contained in the raw material gas can be efficiently decomposed by bringing the film forming raw material gas containing the organic solvent into contact with the oxygen gas and the catalyst.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a configuration diagram showing an example of a film forming apparatus according to an embodiment of the present invention.

  The film forming apparatus shown in FIG. 1 is an apparatus for forming a film by a CVD method using an organometallic compound as a raw material. In a film forming chamber 10, a wafer stage 4 on which a substrate 1 is placed, and a substrate 1 And a shower head 6 disposed above the wafer stage 4.

  The shower head 6 is a gas dispersion apparatus having a structure in which a gas introduced from a gas introduction port 10a in the upper part of the film forming chamber 10 is diffused and supplied to the substrate 1 through a large number of holes without unevenness, and is also called a shower nozzle.

  In addition, an exhaust port 10 b connected to an external vacuum pump 12 through an exhaust pipe 11 is provided at the lower part of the film forming chamber 10. The exhaust pipe 11 is provided with an automatic pressure controller (APC) 14 that controls the exhaust amount based on the measured value of the pressure gauge 13 attached to the film forming chamber 10.

  The gas introduction port 10 a of the film forming chamber 10 is connected to the gas discharge port of the vaporizer 16 via the first gas pipe 15. A first valve 15v is connected to the first gas pipe 15 near the film forming chamber 10, and a bypass pipe 7 connected to the exhaust pipe 11 is connected to the upstream side of the valve 15v.

  A second valve 7v is attached to the bypass pipe 7, and the flow path of the gas flowing through the first gas pipe 15 is controlled by the operation of the first and second valves 15v and 7v. 7 can be selected.

An oxidant supply source 18 is connected to the upstream side of the connection portion with the bypass pipe 7 in the first gas pipe 15 via a second gas pipe 18a. The oxidant (oxidation gas) supplied from the oxidant supply source 18 is, for example, at least one of oxygen (O ₂ ), ozone (O ₃ ), nitric oxide (N ₂ O), and nitrogen dioxide (NO ₂ ). Two gases are used, and in the following description, oxygen gas is taken as an example of the oxidizing agent. A hydrogen gas source is connected to the second gas pipe 18a via a valve (not shown) so that the oxidizing gas can be switched to hydrogen gas.

  The first gas pipe 15, the second gas pipe 18 a, the bypass pipe 7, and their connection parts are each formed from stainless steel. A valve 18v is attached to the second gas pipe 18a.

  A solvent decomposing unit 8 for decomposing the organic solvent is provided in the first gas pipe 15 on the downstream side of the connection portion with the second gas pipe 18a, that is, in the region near the film forming chamber 10. .

  The solvent decomposing unit 8 has a catalyst film 8a formed on the inner surface of a region closer to the film forming chamber 10 than at least the second gas pipe 18a, for example, as in a cross-sectional structure as shown in FIG. As the catalyst film 8, a catalyst made of a film having a noble metal such as platinum (Pt) or iridium (Ir) is formed. In the following explanation, Pt is taken as an example of the catalyst.

  A noble metal such as platinum or iridium or an oxide thereof is, for example, a material constituting an electrode of a ferroelectric capacitor, and may be formed on the substrate 1 in the film forming chamber 10 as a lower electrode by a CVD method.

  The solvent decomposition unit 8 decomposes the organic solvent by a combustion reaction by bringing both the organic solvent and oxygen gas flowing through the first gas pipe 15 into contact with the catalyst. Details thereof will be described later.

  The vaporizer 16 is a device that vaporizes the liquid raw material introduced from the raw material introduction port and discharges it from the gas discharge port to the first gas pipe 15, and atomizes the liquid raw material introduced together with the carrier gas into the vaporization chamber 16a. It has a vaporizing nozzle 16b for discharging, and a heater 16c for preheating and keeping the vaporizing chamber 16a at the vaporizing temperature of the liquid raw material.

  Since the temperature of the vaporization chamber 16a is likely to decrease due to the endothermic action when vaporizing the liquid raw material containing the organometallic compound, the vaporization chamber 16a is made of a material such as stainless steel that can increase the heat capacity in order to prevent this.

  The pressure in the vaporization chamber 16a is controlled by the flow rate of the liquid material introduced into the vaporization nozzle 16b and the flow rate of the carrier gas, although it is influenced by the pressure in the film forming chamber 10 that is the destination of the vaporized gas. Although not particularly illustrated, the vaporizer 16 is provided with a pressure gauge for measuring the pressure in the vaporization chamber 16a.

A third gas pipe 19 and a first liquid supply pipe 21 are connected to the vaporizing nozzle 16b. A carrier gas source 20 for supplying a carrier gas such as argon (Ar) or nitrogen (N ₂ ) to the vaporizing nozzle 16 b is connected to the upstream side of the third gas pipe 19. Further, a raw material output port of a manifold 17 that supplies a liquid raw material to the vaporizing nozzle 16 b is connected to the upstream side of the first liquid supply pipe 21. A valve 19v is attached to the third gas pipe 19.

  The manifold 17 has a structure in which liquid raw materials introduced from second to sixth liquid supply pipes 22a to 22e connected in parallel to the raw material introduction port are mixed and discharged from the raw material discharge port, and the vaporization temperature of the liquid raw material It has a heater 17a that heats the interior to a lower temperature.

  The first liquid supply pipe 21, the first and third gas pipes 15 and 19, the film forming chamber 10, and the like are provided with a heater 9 to prevent the vaporized organometallic compound from aggregating. The heater 9 has a structure capable of controlling the temperature distribution, and is usually set to 220 ° C. to 280 ° C., but is a region downstream of at least the connection portion of the second gas pipe 18a in the first gas pipe 15. Then, the heating temperature can be increased from 300 ° C to 350 ° C.

  Each of the second to sixth liquid supply pipes 22a to 22e connected to the raw material input port of the manifold 17 is connected to first to fifth raw material containers 24 to 24 via liquid mass flow controllers (MFC) 23a to 23e. 28.

  Moreover, the inert gas connected to the inert gas source 30 which enclosed inert gas, such as neon, nitrogen, and argon, in the space formed in each upper part of the 1st-5th raw material containers 24-28. The introduction pipes 31a to 31e are inserted.

  Second to sixth liquid supply pipes 22a to 22e are inserted into the liquid raw materials filled in the first to fifth raw material containers 24 to 28, respectively. Thereby, the liquid raw material filled in the first to fifth raw material containers 24 to 28 is pumped to the manifold 17 through the second to sixth liquid supply pipes 22a to 22e by supplying the inert gas. Will be.

  Each of the first to fifth raw material containers 24 to 28 is a container for storing a liquid raw material in a sealed state, and is made of a material such as stainless steel having excellent corrosion resistance against the liquid raw material. In addition to the second to sixth liquid supply pipes 22a to 22e and the inert gas introduction pipes 31a to 31e associated with the first to fifth raw material containers 24 to 28, O-rings, gaskets, valves and the like are similarly made of stainless steel. Composed.

  In addition, the code | symbol 34a-34p in the figure shows the valve | bulb connected to the 2nd-7th liquid supply pipe | tube 22a-22e, and the code | symbol 35a-35f is connected to each of the inert gas introduction pipe | tubes 31a-31e. Shows the valve.

  By the way, the solvent decomposing portion 8 is composed of a catalyst film 8 a containing a noble metal formed on the inner surface of the first gas pipe 15. The catalyst film 8a may be formed by a plating method or a CVD method.

In the case of forming by the CVD method, for example, the following method is adopted.
First, an organic metal compound containing a metal complex of a metal having a catalytic action and an organic compound, more specifically, a Pt CVD raw material composed of Pt (HFA) ₂ as a raw material and dissolved in an organic solvent. The fifth raw material container 28 is filled. HFA shown in Pt (HFA) ₂ is hexafluoroacetone.

As an organometallic compound for depositing platinum (Pt), there is Pt (DPM) _{2 in} addition to Pt (HFA) _{2. In} the following description, Pt (HFA) ₂ is taken as an example. Note that the chemical formula of DPM shown in Pt (DPM) ₂ is (CH ₃ ) ₃ C—CO—CH—CO—C (CH ₃ ) ₃ .
Further, as an organic solvent, tetrahydrofuran (hereinafter also referred to as THF), butyl acetate (hereinafter also referred to as n-Ba), octane or the like is used, and in the following description, butyl acetate is used as an example. ing.

The Pt concentration in the Pt CVD raw material is set to be equal to or lower than the saturation solubility in butyl acetate. Specifically, it is desirable to adjust the Pt (HFA) ₂ concentration to a concentration range of 0.1 mol / liter (mol / l) to 3.0 mol / l.
The fourth raw material container 27 is filled with an organic solvent.

  First, the Pt CVD raw material filled in the fifth raw material container 28 is pumped to the fifth liquid supply pipe 22e by an inert gas, for example, helium gas, supplied from the inert gas source 30, and further, the mass flow controller 23e. And sent to the vaporizer 16 via the manifold 17. An inert gas such as argon or helium has no problem because it has a low solubility in butyl acetate.

  The flow rate of the Pt CVD raw material in the first liquid supply pipe 21 is controlled by the mass flow controller 23e, and is determined by conditions such as the vaporization capability of the vaporizer 16 and the gas flow rate in the first gas pipe 15.

In the vaporizer 16, the Pt CVD raw material is sprayed together with an inert gas from the vaporization nozzle 16b, further vaporized in the vaporization chamber 16a, and conveyed to the first gas pipe 15. The first gas pipe 15 is preheated to a temperature higher than the vaporization temperature of Pt (HFA) ₂ by the heater 9 upstream from the connection portion of the second gas pipe 18a. Butyl acetate is vaporized by the vaporization temperature of Pt (HFA) ₂ .
Note that a vaporizer for vaporizing an organometallic raw material containing Pt may be provided separately from a vaporizer for vaporizing other organometallic raw materials.

  Then, as shown in FIG. 2, the heater 9 capable of controlling the temperature distribution along the gas flow path evaporates the downstream side of at least the connection portion of the first gas pipe 15 with the second gas pipe. Heat to 300 ° C to 350 ° C higher than the temperature. Specifically, for example, the first region 15a between the connection portion of the second pipe 18a and the connection portion of the bypass pipe 7 is set to 300 ° C., and the second region 15b downstream of the bypass pipe 7 is set to 350 ° C. Then, the third region 15c between the second region 15b and the first region 15a and the other region 15e are set to the vaporization temperature of the CVD raw material for Pt.

Thus, Pt (DPM) ₂ flowing in the first gas pipe 15 is decomposed in the first and second regions 15a and 15b to form a catalyst film 8a made of Pt on the inner surface of the first gas pipe 15. .
The catalyst film 8a having Pt formed by this method contains carbon. The carbon is a decomposition product of the reaction of Pt (HFA) ₂ and butyl acetate. It is desirable to remove carbon remaining in the catalyst film 8a because it does not contribute to the catalytic action.

As a method for removing residual carbon, there is a method of flowing hydrogen (H ₂ ) gas into the first gas pipe 15 covered with the Pt catalyst film 8a. By supplying hydrogen gas to the surface of the catalyst film 8a, hydrocarbon (CH _x ) having a vapor pressure is formed, and carbon is excluded from the catalyst film 8a. At this time, it is desirable to heat the first gas pipe 15 at, for example, about 350 ° C. in order to promote the generation of CH _x . The hydrogen gas may be supplied from the second gas pipe 18a.

By the above method, the catalyst film 8a is formed on the inner surface of the first gas pipe 15 on the downstream side of the oxidizing gas introduction part.
Next, a method for forming the PZT film 2 on the substrate 1 using the film forming apparatus provided with the solvent decomposition unit 8 will be described.

First, the first CVD raw material in which Pb (DMHD) ₂ was dissolved in butyl acetate and liquefied was filled in the first raw material container 24, and Zr (DMHD) ₄ was dissolved in butyl acetate and liquefied. The second CVD source is filled in the second source vessel 25, and the third CVD source obtained by dissolving Ti (OiPr) ₂ (DPM) ₂ in butyl acetate is liquefied in the third source vessel 26. The fourth raw material container 27 is filled with butyl acetate as an organic solvent.
Pb (DMHD) ₂ , Zr (DMHD) ₄ , and Ti (OiPr) ₂ (DPM) ₂ are each an organometallic compound containing a metal complex of a metal and an organic compound. The chemical formula of DMHD shown in Pb (DMHD) ₂ and Zr (DMHD) ₄ is (CH ₃ ) ₂ CHCOCHCOCH (CH ₃ ) ₂ . Even if Ti (O iPr) ₂ (DMHD) ₂ is used instead of Ti (OiPr) ₂ (DPM) ₂ , the effect is the same.

The concentration of Pb (DMHD) ₂ in the first CVD material, the concentration of Zr (DMHD) ₄ in the second CVD material, and Ti (OiPr) ₂ (DPM) ₂ in the third CVD material The concentration is adjusted in the range of 0.5 mol / l to 1.0 mol / l, respectively.

Each organometallic compound of Pb (DMHD) ₂ , Zr (DMHD) ₄ , and Ti (OiPr) ₂ (DPM) ₂ is a white solid at room temperature and is in a fine powder form.

  The same effect can be obtained by selecting either tetrahydrofuran or butyl acetate as the organic solvent used for forming the PZT film.

  In order to form a PZT film, first, the first to fourth raw material containers 24 to 27 are filled with an inert gas to increase the pressure in the internal space, and further, the second to fifth supply gas is supplied. By controlling the valves 34a to 34p connected to the liquid pipes 22a to 22d, the CVD raw material in the first to third raw material containers 24 to 26 and the organic solvent in the fourth raw material container 28 are supplied to the manifold 17. Pump.

Thereby, the first to third CVD raw materials are mixed in the manifold 17 together with the organic solvent, and further conveyed to the vaporizer 16 through the first liquid supply pipe 21.
The flow rate of the liquid raw material in the first liquid supply pipe 21 is determined by conditions such as the vaporization capability of the vaporizer 16 and the gas flow rate to the film forming chamber 10, and is controlled by the mass flow controllers 23a to 23e.

  The first to third CVD raw materials and organic solvent pumped from the manifold 17 are sprayed into the vaporizing chamber 16a from the vaporizing nozzle 16b together with the carrier gas, and further atomized to the first to third CVD raw materials and organic solvent. Is vaporized by the heater 16c to become a CVD source gas.

As the vaporization conditions, the temperature in the vaporization chamber 16a is set in the range of 220 ° C to 280 ° C, preferably 250 ° C to 270 ° C, and the vaporization pressure in the vaporization chamber 16a is set to 20 Torr (2666.4 Pa). Set as follows. The temperature control is performed by the heater 16c.
The vaporization pressure is influenced by the pressure in the film forming chamber 10, but is controlled by adjusting the flow rates of the first to third CVD raw materials, the flow rate of the carrier gas, and the like.

The CVD raw material vaporized in the vaporizer 16 is transported to the first gas pipe 15 together with the carrier gas, and further, oxygen gas is added from the oxidant supply source 18 in the middle of the first gas pipe 15, and the solvent decomposition section. Pass 8 The first gas pipe 15 is heated by the heater 9 to a range of 220 ° C. to 280 ° C.
The flow rate of the oxygen gas is set higher than that in a conventional film forming apparatus that does not have the solvent decomposing unit 8.

  In the solvent decomposition unit 8, butyl acetate in the CVD source gas is decomposed by causing a combustion reaction with oxygen. The combustion reaction is further promoted by the catalyst film 8a in the solvent decomposition section 8. In this case, the solvent decomposing unit 8 is set to the same temperature as other regions of the first gas pipe 15, that is, a range of 280 ° C. or lower and 220 ° C. or higher. Details of the catalytic action in the solvent decomposition unit 8 will be described later.

  Thus, the CVD source gas and oxygen gas with reduced organic solvent components flow into the shower head 6 from the first gas pipe 15, diffuse therein, and are further released toward the substrate 1.

  Thereby, the CVD source gas and the oxidizing gas reach the surface of the substrate 1 without any unevenness, and the PZT film 2 is formed on the substrate 1 by repeating the reaction and decomposition there. When a film made of iridium, iridium oxide, platinum, or platinum oxide is formed on the surface of the substrate 1, the crystal of the PZT film 2 exhibits (111) preferential orientation.

  After the formation of the PZT film 2, the gas flowing in the first gas pipe 15 is transferred to the exhaust pipe 11 through the bypass pipe 7 with the flow path changed by switching the open / close valves 15 v and 7 v.

  Next, a ferroelectric capacitor composed of a PZT film formed using the film forming apparatus according to the present embodiment and a strong capacitor composed of a PZT film formed using the conventional film forming apparatus. The dielectric capacitor is compared.

  In a ferroelectric capacitor, ideally, the capacity tends to increase as the PZT film, which is a dielectric film, is made thinner. However, even if the PZT film is thinned, the capacitance may not increase. In this case, in order to miniaturize the ferroelectric capacitor, the capacitor capacity may not decrease at least as the PZT film is thinned. preferable.

  Using the film forming apparatus of the present embodiment shown in FIG. 1, a CVD source gas to which oxygen gas is added is passed through the solvent decomposition unit 8 and supplied to the substrate 1 to form the PZT film 2, and the PZT film When the relationship between the thickness and the capacitance of the ferroelectric capacitor was examined, the characteristics shown by the solid line in FIG. 3 were obtained.

According to the characteristics, even if the thickness of the PZT film is reduced from 120 nm to 80 nm, the capacitance of the capacitor hardly changes, and when the thickness is reduced from 80 nm to 60 nm, the capacitance of the capacitor decreases but the amount is small. As a result, it is possible to suppress a decrease in the capacitance of the capacitor by applying the film forming method of the present embodiment to the manufacturing process of the ferroelectric capacitor.
Note that the capacitor capacity shown on the vertical axis in FIG. 3 is a value normalized by assuming that the capacitor capacity (unit: μC / cm ² ) when the thickness of the PZT film is 120 nm is “1”.

On the other hand, when the conventional deposition apparatus shown in FIG. 10 was used and the PZT film was formed by supplying the substrate with the source gas obtained by heating and sublimating the organometallic compound, the relationship between the thickness of the PZT film and the capacitance of the capacitor was obtained. The relationship was as shown by the broken line in FIG.
According to the characteristics, as in the present embodiment, the capacitance of the capacitor hardly changes even if the thickness of the PZT film is reduced from 120 nm to 60 nm.

  On the other hand, when a PZT film was formed by supplying a CVD source gas to which oxygen gas was added to a substrate using a conventional film forming apparatus configured without the solvent decomposition unit 8, The relationship between the thickness and the capacitance of the ferroelectric capacitor has a characteristic as shown by a one-dot chain line in FIG.

  According to the characteristics, even if the thickness of the PZT film is reduced from 120 nm to 100 nm, the capacitance of the capacitor hardly changes. However, as the thickness of the PZT film is reduced from 100 nm, the capacitance of the capacitor is greatly reduced, and the ferroelectric capacitor is reduced. This is not suitable for miniaturization.

  From the above, it is possible to form a PZT film with good film quality by using the source gas obtained by adding oxygen to the CVD source gas and decomposing the organic solvent in the solvent decomposition unit 8, thereby reducing the capacitance of the capacitor due to the thinning of the PZT film. It became clear that it could be suppressed.

  Moreover, even if the PZT film is formed using the raw material gas obtained by sublimating the organometallic compound, it is possible to suppress the decrease in the capacitor capacity accompanying the thinning of the PZT film. However, according to this film forming method, as shown by the broken line in FIG. 4, the capacity of the capacitor decreases as the cumulative number of substrates processed in the film forming chamber increases, so that the mass productivity is inferior. This is because the organic metal compound aggregates in the raw material container as described in the background art section.

  When using a CVD raw material formed by dissolving an organometallic compound in an organic solvent, as shown by the one-dot chain line in FIG. There is no significant change in capacity. Thereby, it can be seen that the CVD raw material can be stably supplied to the film forming chamber.

Next, the combustion of the organic solvent in the solvent decomposition unit 8 of the film forming apparatus according to this embodiment will be described.
First, a catalyst film was formed on a substrate, the substrate was placed in a vacuum chamber, and a thermocouple was connected to the substrate. Then, the substrate was heated with a heater in the vacuum chamber, and gas was introduced into the vacuum chamber through the gas pipe, and the inside of the vacuum chamber was decompressed through the exhaust pipe. In addition, although it experimented by forming Ir instead of Pt as a catalyst film, since both materials have a catalytic action, there is no difference.

In such an apparatus, the substrate heating temperature and the substrate surface temperature usually have a linear relationship.
Therefore, the substrate surface temperature was investigated by changing the substrate heating temperature for each of the case where only oxygen was supplied to the substrate and the case where the mixed gas of butyl acetate and oxygen was supplied to the substrate. As shown in FIG. A relationship was obtained.

  The horizontal and vertical axes in FIG. 5 are the substrate heating temperature value and the substrate rising temperature value, respectively. The substrate rising temperature indicates the difference between the substrate temperature measured by the thermocouple and the heating temperature of the heater.

  The gas flow rates of butyl acetate and oxygen were 1 ccm and 5 slm, respectively. The pressure in the vacuum chamber was 1 Torr (about 133 Pa). Further, the substrate heating temperature was changed from 100 ° C. to 300 ° C.

  As shown by a broken line in FIG. 5, when only oxygen gas was introduced into the vacuum chamber, the substrate rising temperature was about several degrees. That is, there is almost no difference between the heating temperature and the substrate surface temperature, and the substrate surface temperature increases with the heating temperature and has a linear relationship with the heating temperature.

  On the other hand, when a mixed gas of oxygen and butyl acetate is introduced into the vacuum chamber, as shown by the solid line in FIG. 5, the substrate rising temperature becomes higher than that of oxygen alone, and the substrate surface temperature becomes the substrate heating temperature. On the other hand, it is not a linear relationship. This is due to the combustion reaction of oxygen and butyl acetate.

  Also, when supplying a mixed gas of oxygen and butyl acetate to the substrate, if the substrate heating temperature is set to 150 ° C. or higher, the substrate rising temperature gradually increases, and if the substrate heating temperature is about 200 ° C., the substrate rising temperature is As the substrate heating temperature is increased from about 200 ° C., the substrate rising temperature gradually decreases and becomes slightly higher than the substrate heating temperature around 300 ° C.

  This is because the phenomenon that the substrate temperature rises rapidly when the substrate heating temperature is 150 ° C. or higher contributes to the catalytic action of Ir. That is, the combustion reaction of oxygen and butyl acetate is accelerated by the catalytic action of Ir, and the temperature of the substrate becomes higher than the heating temperature.

  Incidentally, Japanese Patent Application Laid-Open No. 2004-335607 shown in the column of the prior art describes that an organic solvent component is thermally decomposed by a rhodium catalyst without adding oxygen to an organic metal source gas. However, since this thermal decomposition does not involve a combustion reaction due to the addition of oxygen, there is no effect of promoting the combustion reaction by the catalyst. When the organic solvent component is thermally decomposed with a rhodium catalyst, the substrate measurement temperature and the substrate heating temperature are substantially the same.

  As described above, according to the film forming method and film forming apparatus of this embodiment, when the CVD source gas, oxygen gas, and catalyst are brought into contact, the organic solvent can be decomposed even at a temperature lower than the decomposition temperature of the organometallic compound. . As a result, the influence of the organic solvent when forming the PZT film can be greatly reduced.

  Note that the film forming method according to the above-described embodiment is not only applied for forming a PZT film, but also for forming a PZT-based film in which a dopant such as lanthanum (La) or calcium (Ca) is added to PZT. Applicable. The present invention can also be applied to the case of forming a film other than PZT, for example, a strontium bismuth tantalum oxide (SBT) film.

By the way, although said solvent decomposition | disassembly part 8 is comprised from the catalyst film 8a formed in the inner surface of the 1st gas piping 15, it is not restricted to such a structure. For example, the solvent decomposition unit 8 may be provided in the shower head 6 as shown in FIG.
The shower head 6 shown in FIG. 6 has a structure in which a solvent decomposition portion 38 configured by covering the inner surface of the shower head 6 is provided, and a method for forming the catalyst film is the same as that of the catalyst film 8a shown in FIG. A method similar to the forming method is employed.

  That is, the first gas pipe 15 and the valve 15v connecting the vaporizer 16 and the film forming chamber 10 are set to the vaporization temperature of the CVD raw material, and the shower head 6 is heated to 300 ° C. to 350 ° C. higher than the vaporization temperature. . Regarding the temperature control method of the shower head 6, when the shower head 6 is equipped with a heater, the temperature is controlled by the heater, but when the heater is not equipped, the substrate heating heater 5 is used. Then, the temperature is controlled to 300 ° C. to 350 ° C. by the radiant heat from the heater 5.

Then, a source gas containing an organic solvent and an organometallic compound for Pt is introduced from the vaporizer 16 into the film forming chamber 10 through the first gas pipe 15. For example, Pt (HFA) ₂ is used as the organometallic compound for Pt. In this case, by setting the temperature of the first gas pipe 15 to 280 ° C. or lower, the inner surface is not actively covered with Pt.

  The source gas introduced into the film forming chamber 10 is thermally decomposed inside the shower head 6 and covers the inside with a Pt film. Residual carbon in the Pt film can be removed by the method described above. This Pt film is used as a catalyst film and constitutes the solvent decomposition unit 38. The catalyst film may be formed on the surface of the shower head 6 facing the substrate 1.

The solvent decomposition part 38 provided in the shower head 6 may be used together with the solvent decomposition part 8 shown in FIG.
Although the above-mentioned solvent decomposition parts 8 and 38 are constituted by a catalyst film formed on the surface of the first gas pipe 15 and the inner surface of the shower head 6, the solvent decomposition part is not limited to those structures. For example, a gas filter having a structure shown in FIGS. 7A to 7C may be used as the solvent decomposition unit 39.

  The solvent decomposing portion 39 shown in FIG. 7A has a structure in which a catalyst container 39d is filled with a bead aggregate 39a having at least a surface made of Pt sandwiched between mesh plates 39b and 39c from above and below. Moreover, the solvent decomposition | disassembly part 39 shown to FIG. 7B has the structure which has arrange | positioned the mesh 39e which the surface consists of Pt in the catalyst container 39d. Furthermore, the solvent decomposing portion 39 shown in FIG. 7C has a structure in which a porous body 39f having at least a portion through which gas passes is made of Pt is arranged in the catalyst container 39d.

The catalyst container 39d is made of a material that does not react with the organic catalyst, for example, stainless steel, like the raw material containers 24-28.
The Pt of the bead assembly 39a body or mesh 39e or porous body 39f in the catalyst container 39d shown in FIGS. 7A to 7C has a structure that does not affect the vaporization pressure of the vaporizer 16, respectively. For example, the minimum diameter of the beads constituting the bead assembly 39a shown in FIG. 7A is 1 mm.

The method for coating the surface of the bead aggregate 39a, mesh 29e or porous body 39f with Pt may be the same as the method for forming the catalyst film 8a shown in FIG.
The gas filter that is the solvent decomposition unit 39 is installed on the downstream side of the oxidant introduction unit in the first gas pipe 15, that is, near the film forming chamber 10. Further, when the organic solvent is decomposed by the combustion reaction and catalytic action in the gas filter 39, the catalyst container 39 d is heated to 220 ° C. or higher and 280 ° C. or lower by the heater 9 surrounding the gas filter 39.

A CVD source gas for producing PZT is introduced into the film forming chamber 10 through a solvent decomposition unit 39 constituted by a gas filter, and butyl acetate is combusted by the catalytic action of Pt in the solvent decomposition unit 39.
In FIGS. 7A to 7C, reference numerals 39g and 39h denote valves.

By the way, the combustion reaction of butyl acetate and oxygen, that is, H ₂ O, CH _{x and the} like produced by the oxidation of butyl acetate are mostly introduced from the exhaust port 10b even if they are introduced into the film forming chamber 10 because of their low vaporization temperature. Discharged. However, it is preferred that such products are removed before reaching the substrate 1. In order to remove the product, as shown in FIG. 8, a molecular sieve (molecular sieve) 40 for capturing the product may be disposed on the gas downstream side of the solvent decomposition unit 8.

In addition, although Pt was mentioned as an example as a catalyst which comprises said solvent decomposition | disassembly part 8,38,39, noble metals, such as rhodium (Rh), iridium (Ir), palladium (Pd) other than Pt, or A material containing the noble metal may be used. There is Rh (DPM) ₂ as an organometallic compound of Rh, Ir (DPM) ₂ as an organometallic compound of Ir, and Pd (DPM) ₂ as an organometallic compound of Pd.

Next, a method for manufacturing a semiconductor device will be described as an example to which the above-described film forming method is applied.
9A to 9I are cross-sectional views showing the manufacturing steps of the semiconductor device according to the first embodiment of the present invention.

First, steps required until a sectional structure shown in FIG. 9A is formed will be described.
9A, by selectively introducing either a p-type impurity or an n-type impurity into a predetermined active region in the memory cell region A and the peripheral circuit region B of the p-type or n-type silicon (semiconductor) substrate 41. The first well 42a is formed in the active region of the memory cell region A, and the second well 42b is formed in the active region of the peripheral circuit region B.

An element isolation insulating film 43 is formed around the active region of the silicon substrate 41.
On the surface of the silicon substrate 41, for example, a silicon oxide film is formed as a gate insulating film 44 by a thermal oxidation method. Further, first and second gate electrodes 45a and 45b are formed on the gate insulating film 44 on the first well 42a with a gap therebetween.

On both sides of the two gate electrodes 45a and 45b formed on the first well 42a via the gate insulating film 44, an impurity having a conductivity type opposite to that of the first well 42a is ion-implanted into the silicon substrate 1 and extended. Regions 47a, 47b and 47c are formed.
Next, steps required until a structure shown in FIG. 9B is formed will be described.

  First, an insulating sidewall 50 is formed on the side surfaces of the gate electrodes 45a and 45b by forming a silicon oxide film and then performing etch back. Subsequently, impurities having the same conductivity type as that of the extension regions 47a, 47b, 47c are ion-implanted into the first well 42a using the gate electrodes 45a, 45b and the sidewalls 50 as a mask, thereby forming the extension regions 47a, 47b, 47c. First, second, and third high-concentration impurity diffusion regions 48a, 48b, and 48c that partially overlap are formed. The first, second, and third high-concentration impurity diffusion regions 48a, 48b, and 48c constitute first, second, and third source / drain regions 49a, 49b, and 49c together with the extension regions 47a, 47b, and 47c, respectively. To do.

  Subsequently, for example, a cobalt film is formed on the entire surface by, eg, sputtering. Further, by heat-treating the cobalt film, the doped silicon film constituting the gate electrodes 45a and 45b and the cobalt film undergo a silicide reaction, and a silicide layer 46 is formed on the upper surfaces of the gate electrodes 45a and 45b. Although not shown, silicide layers are also formed in the upper layer portions of the high concentration impurity diffusion regions 48a, 48b, 48c. Thereafter, the unreacted cobalt film is removed using hydrofluoric acid or the like.

Thus, the first well 42a, the gate insulating film 44, the first gate electrode 45a, the first and second source / drain region 49a, the first MOS transistors _{T 1} by 49b or the like is configured, also, the 1 well 42a, the gate insulating film 44, the second gate electrode 45b, the second, third source / drain region 49b, a second MOS transistor _{T 2} is constituted by such 49c.

Subsequently, the MOS transistors T ₁ and T ₂ are covered with the cover insulating film 51 and the first interlayer insulating film 52, and each of the first, second and third high-concentration impurity diffusion regions 48 a, 48 b and 48 c is further covered. First, second and third plug electrodes 55a, 55b and 55c are formed thereon. The first, second and third plug electrodes 55a, 55b and 55c are formed by the following process.

First, a cover insulating film 51 of, for example, silicon oxynitride (SiON) covering the first and second MOS transistors T ₁ and T ₂ is formed on the silicon substrate 41 by plasma chemical vapor deposition (P-CVD). .

Next, a silicon oxide film (SiO ₂ film) is grown on the cover film 51 by P-CVD using TEOS (tetraethoxysilane) gas, and this silicon oxide film is used as a first interlayer insulating film 52. Subsequently, as the densification treatment of the first interlayer insulating film 52, the first interlayer insulating film 52 is heat-treated at a predetermined temperature and for a predetermined time in a normal pressure nitrogen atmosphere. Thereafter, the upper surface of the first interlayer insulating film 52 is polished and planarized by a chemical mechanical polishing (CMP) method.

  By patterning the cover insulating film 51 and the first interlayer insulating film 52 by photolithography, the first and second source / drain regions 49a, 49b, and 49c are respectively formed on the first, second, and third source / drain regions 49a, 49b, and 49c. Second and third contact holes 52a, 52b and 52c are formed. Further, on the inner walls and bottom surfaces of the first, second and third contact holes 52a, 52b and 52c, a Ti film having a thickness of 30 nm and a TiN film having a thickness of 50 nm are sequentially formed by sputtering as a glue (adhesion) film 53. Form.

  Further, a tungsten (W) film 54 having a thickness for embedding the first, second and third contact holes 52a, 52b and 52c is formed on the glue film 53 by the CVD method. Thereafter, the W film 54 and the glue film 53 are polished by CMP to expose the upper surface of the first interlayer insulating film 52.

  As a result, the W film 54 and the glue film 53 left in the first, second, and third contact holes 51a, 52b, 52c become the first, second, and third plug electrodes 55a, 55b, 55c, respectively. It becomes.

Next, steps required until a structure shown in FIG. 9C is formed will be described.
First, a titanium (Ti) film 56a is formed to a thickness of 20 nm on the first interlayer insulating film 52 and the first, second, and third plug electrodes 55a, 55b, and 15c by sputtering. The Ti film is one of metal films having a strong self-orientation property, and has a good crystallinity oriented in the c-axis. Subsequently, the TiN film 56 is formed by performing rapid thermal annealing (RTA) treatment in a nitrogen (N ₂ ) atmosphere and nitriding the Ti film.

  The TiN film 56 is an antioxidant film and has good crystallinity strongly oriented in <111> in order to inherit the crystallinity of the Ti film. The Ti film is nitrided because Ti is easily oxidized, and the oxidation resistance is improved by nitriding. The TiN film 56 covers the first interlayer insulating film 52 and the plug electrodes 55a, 55b, and 55c, and functions as an orientation improving film that is formed in the next step and improves the crystallinity of the film.

  Further, an oxygen barrier film 57 and an electrode film 58 are sequentially formed on the TiN film 56. The oxygen barrier film 47 is a film having an antioxidant function such as a titanium aluminum nitride (TiAlN) film having a thickness of 100 nm formed by sputtering, for example. The electrode film 58 is an Ir film formed by a sputtering method and has a thickness of 100 nm, for example. The electrode film 58 may be another noble metal film such as a Pt film or a noble metal oxide film such as iridium oxide. These films may be formed by, for example, filling a fifth raw material container 28 shown in FIG. 1 with an organic metal raw material in which an organic metal compound is dissolved in a solvent and using the film forming apparatus shown in FIG.

Next, as shown in FIG. 9D, for example, a PZT film 59 is formed as a ferroelectric film on the electrode film 58 to a thickness of, for example, 150 nm or less.
The PZT film 59 is a CVD in which Pb (DMHD) ₂ , Zr (DMHD) ₄ and Ti (O iPr) ₂ (DPM) ₂ are dissolved in an organic solvent using the film forming apparatus shown in FIG. It is formed by CVD using raw materials. The liquid material is vaporized by the vaporizer 16 shown in FIG. 1, and then supplied to the film forming chamber 10 through the solvent decomposition section 8 (38, 39) shown in FIG. 2, FIG. 6 or FIG. In the solvent decomposition unit 8 (38, 39), the combustion reaction of the organic solvent and the oxygen gas in the CVD source gas is promoted and decomposed at a temperature of 220 ° C. or higher and 280 ° C. or lower.

  Thereby, the PZT film 59 is formed on the electrode film 58 by the reaction of the CVD raw material in which the organic solvent is reduced. The substrate temperature at the time of forming the PZT film 59 is, for example, 620 ° C., and the pressure of the growth atmosphere is, for example, 5 Torr (about 667 Pa).

  As another ferroelectric film of the PZT film 59, a PZT film in which a dopant such as Ca, Sr, La, Nb or the like is added to PZT may be formed by a CVD method, and an organic metal material is used as a dopant material. Is done.

  Next, the PZT film 59 is annealed under reduced pressure in an oxygen-containing atmosphere, thereby reducing oxygen vacancies in the PZT film 59.

Next, steps required until a structure shown in FIG.
First, an iridium oxide (IrO _x ) film 61 having a thickness of, for example, 150 nm is formed on the PZT film 59 by sputtering. Here, iridium oxide, which is a conductive oxide, is used to improve the resistance to hydrogen deterioration of the PZT film 59, but a Pt film, SrRuO ₃ (SRO) may be used.

  Subsequently, a noble metal film 62 such as iridium having a thickness of 100 nm is formed on the iridium oxide film 61 by a sputtering method. The noble metal film 62 and the underlying iridium oxide film 61 serve as an upper electrode film for a ferroelectric capacitor.

  Further, a hard mask 63 covering the capacitor formation region is formed on the noble metal film 62. The hard mask 63 is formed by forming a TiN film 63a having a thickness of 200 nm by a sputtering method, and forming a silicon oxide film 63b having a thickness of 700 nm thereon by a plasma CVD method using TEOS, which is formed by a photolithography method. It is formed by patterning.

  Next, each layer from the noble metal film 62 to the lower Ir electrode film 58 in the region exposed from the hard mask 63 is continuously and collectively etched at a high temperature using an inductively coupled plasma (ICP) etching apparatus. Thereafter, the silicon oxide film 63b constituting the hard mask 63 is removed by reactive ion etching. Further, after removing the TiN film 63a, the TiNAlN film 57, and the TiN film 56 constituting the hard mask 63 by reactive ion etching, those etching residues are removed by wet processing. Thereby, the ferroelectric capacitor Q having the stack structure shown in FIG. 9F is formed.

  Here, the TiN film 56, the oxygen barrier film 57, and the electrode film 58 constitute a lower electrode 64 of the ferroelectric capacitor Q, the ferroelectric film 59 serves as a capacitor dielectric film of the ferroelectric capacitor Q, and The first and second iridium oxide films 60 and 61 and the noble metal film 62 constitute the upper electrode 65 of the ferroelectric capacitor Q. In the stacked capacitor structure, the lower electrode 64 of the ferroelectric capacitor Q is formed in an island shape so as to cover the plug electrodes 55a and 55c and their peripheral regions.

Next, steps required until a structure shown in FIG. 9G is formed will be described.
First, a first aluminum oxide (Al ₂ O ₃ ; hereinafter referred to as ALO) film 66 is formed as a protective film on the surface of the ferroelectric capacitor Q, the interlayer insulating film 52 and the second plug electrode 55b. . Here, the first ALO film 66 with good step coverage is formed to a thickness of 40 nm by an ALD (ALD; Atomic Layer Deposition) method.

  Subsequently, a silicon oxide film having a film thickness of about 1500 nm to 2500 nm is formed on the first ALO film 66 covering the ferroelectric capacitor Q as the second interlayer insulating film 67 by, for example, a plasma CVD method using TEOS. . Thereafter, the upper surface of the second interlayer insulating film 67 is polished by CMP treatment.

After the CMP process, for example, a N ₂ O plasma annealing process is performed for the purpose of dehydrating the second interlayer insulating film 67. Subsequently, a second ALO film 68 is formed to a thickness of 50 nm on the dehydrated second interlayer insulating film 67 by high frequency sputtering. Further, a silicon oxide film is formed on the second ALO film 68 as the third interlayer insulating film 69 by a plasma CVD method using TEOS.

Next, steps required until a structure shown in FIG. 9H is formed will be described.
First, a part of the third interlayer insulating film 69, the second ALO film 68, the second interlayer insulating film 67, and the first ALO film 66 is etched by a photolithography method using a photoresist as a mask. First and third via holes 70a and 70c are formed to expose the surface of the upper electrode 65 above the first and third plug electrodes 55a and 55c.

Thereafter, the final recovery annealing for improving the film quality of the ferroelectric capacitor Q is performed. As recovery annealing in this case, for example, annealing is performed for about 60 minutes in a furnace having a temperature of about 500 ° C. and an O ₂ atmosphere.

  Subsequently, the third interlayer insulating film 69, the second ALO film 68, the second interlayer insulating film 67, and a part of the first ALO film 66 are etched by photolithography using a photoresist as a mask. Thus, a second via hole 70b having a depth reaching the upper surface of the second plug electrode 55b is formed.

  Further, a TiN film having a thickness of about 100 nm is deposited on the first to third via holes 70 a to 70 c and the third interlayer insulating film 69 by, for example, a sputtering method, and this is used as the glue film 71.

  Subsequently, after depositing a tungsten film 72 having a thickness sufficient to fill the first to third via holes 70a to 70c, the surface of the third interlayer insulating film 69 is exposed by the CMP method until the surface of the third interlayer insulating film 69 is exposed. By polishing and planarizing the film 71, first to third via plug electrodes 73a to 73c are formed in the first to third via holes 70a to 70c, respectively. At this stage, a via-to-via contact can be realized by the second via plug electrode 73b and the second plug electrode 55b therebelow.

Next, as shown in FIG. 9I, a metal wiring 75a and a metal pad 75b composed of the lower glue film 74a, the wiring film 74b, and the upper glue film 74c are formed.
Specifically, first, a lower glue film 74a made of a Ti film having a thickness of about 60 nm and a TiN film having a thickness of about 30 nm is formed on the entire surface by, eg, sputtering, and further made of an AlCu alloy having a thickness of about 400 nm. A wiring film 74b is formed, and then an upper glue film 74c composed of a Ti film having a thickness of about 5 nm and a TiN film having a thickness of about 70 nm is sequentially laminated.

  Subsequently, the lower glue film 74a, the wiring film 74b, and the upper glue film 74c are patterned into a predetermined shape by using a photolithography technique, so that the metal wiring connected to the first and third via plug electrodes 73a and 73c. 75a and a metal pad 75b connected to the second via plug electrode 72b are formed.

  Thereafter, although not shown in the drawing, the stack type ferroelectric memory according to the present embodiment is completed through various processes such as formation of an interlayer insulating film and further upper layer wiring.

  According to the above process, after adding oxygen gas to the CVD source gas used for forming the PZT film 59 which is a ferroelectric film, the combustion reaction of the organic solvent and oxygen gas in the CVD source gas is subjected to solvent decomposition. It is promoted by part 8 (38, 39). As a result, the PZT film 59 constituting the ferroelectric capacitor Q is thinly formed to prevent the capacitance of the capacitor from being lowered, and the ferroelectric capacitor Q can be miniaturized.

  The embodiment described above is merely given as a typical example, and it is obvious for those skilled in the art to combine the components and modifications and variations thereof, and those skilled in the art described the principle of the present invention and the claims. Obviously, various modifications can be made to the above-described embodiments without departing from the scope of the invention.

FIG. 1 is a configuration diagram showing a film forming apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram showing a first solvent decomposition unit constituting the film forming apparatus according to the embodiment of the present invention. FIG. 3 shows the relationship between the capacitance of a ferroelectric capacitor composed of a PZT film and the PZT film thickness for each of the PZT films formed by the film forming apparatus according to the embodiment of the present invention and the conventional film forming apparatus. FIG. FIG. 4 is a diagram showing the relationship between the substrate heating temperature and the actual substrate temperature for the decomposition of the organic solvent used in the film forming method and film forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram showing the relationship between the substrate heating temperature and the actual substrate temperature for the decomposition of the organic solvent used in the film forming method and film forming apparatus according to the embodiment of the present invention. FIG. 6 is a cross-sectional view showing a second solvent decomposition unit constituting the film forming apparatus according to the embodiment of the present invention. FIG. 7 is a cross-sectional view showing a third solvent decomposition unit constituting the film forming apparatus according to the embodiment of the present invention. FIG. 8 is a partial cross-sectional view showing a state in which a molecular sieve is connected to the solvent decomposition part of the film forming apparatus according to the embodiment of the present invention. 9A to 9C are cross-sectional views (part 1) illustrating the manufacturing process of the semiconductor device according to the embodiment of the present invention. 9D and 9E are cross-sectional views (part 2) illustrating the manufacturing process of the semiconductor device according to the embodiment of the present invention. 9F and 9G are cross-sectional views (part 3) illustrating the manufacturing process of the semiconductor device according to the embodiment of the present invention. 9H and 9I are cross-sectional views (part 4) illustrating the manufacturing process of the semiconductor device according to the embodiment of the present invention. FIG. 10 is a block diagram showing a film forming apparatus according to the prior art. 11A and 11B are cross-sectional views of a raw material container used in a conventional film forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 PZT film 4 Wafer stage 5 Heater 6 Shower head 7 Bypass piping 8, 38, 39 Solvent decomposition part 9 Heater 10 Deposition chamber 15 Gas piping 16 Vaporizer 17 Manifold 18 Oxidant supply source 23a-23e Mass flow controller 24- 28 Raw material containers 21 and 22a to 22e Supply pipe 40 Molecular sieve 41 Silicon substrate (semiconductor substrate)
59 PZT film 64 Lower electrode 65 Upper electrode Q capacitor

Claims (7)

A step of generating a raw material gas by vaporizing a solution in which a metal organic compound is dissolved in an organic solvent;
Introducing the source gas into a reaction chamber in which a substrate is installed,
Before the source gas reaches the substrate, a catalyst containing a noble metal is brought into contact with the source gas and oxygen gas to decompose the organic solvent, and then a film containing the metal is formed on the substrate. A film forming method characterized by the above.   The film forming method according to claim 1, wherein the step of generating the source gas vaporizes the solution at a temperature of 280 ° C. or lower and 220 ° C. or higher. Before the step of generating the source gas,
A solution obtained by dissolving a first organometallic compound including a metal complex of a noble metal and a first organic compound in an organic solvent is vaporized, and the catalyst is deposited in a passage for introducing the source gas into the reaction chamber. The film forming method according to claim 1, further comprising a step.   The film deposition method according to claim 3, wherein in the step of depositing the catalyst, the inside of the passage is heated to 300 to 350 ° C. A reaction chamber in which the substrate is installed;
A vaporizer that generates a raw material gas by vaporizing a solution in which a metal organic compound is dissolved in an organic solvent;
A passage for introducing the raw material gas generated in the vaporizer into the reaction chamber;
An oxygen gas supply unit for supplying oxygen gas into the passage;
A film forming apparatus comprising: a solvent decomposing unit that contacts the organic solvent in the source gas, the oxygen gas, and a catalyst containing a noble metal to decompose the organic solvent.   The film forming apparatus according to claim 5, wherein the solvent decomposing unit is disposed in the passage. Forming a lower electrode above the semiconductor substrate;
Forming a dielectric film on the lower electrode;
Forming an upper electrode on the dielectric film,
The step of forming the dielectric film includes
Vaporizing a solution in which a metal organic compound is dissolved in an organic solvent to generate a raw material gas, and supplying the semiconductor substrate with the lower electrode formed thereon,
Before the source gas reaches the semiconductor substrate on which the lower electrode is formed, a catalyst containing a noble metal, the source gas and oxygen gas are brought into contact with each other to decompose the organic solvent and deposit a dielectric film. A method of manufacturing a semiconductor device.

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