JP3437130B2 - Method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a CVD (Chemical Vapor) method using an organic metal or an organic metal complex as a raw material.
that by the or Deposition) method method for the manufacture of semi-conductor devices.

[0002]

2. Description of the Related Art In recent years, as electronic equipment has been highly functionalized, a DR using a high dielectric material or a ferroelectric film in a capacitor portion.
AM (Dynamic Random Access Memory) and FeRAM
A large-capacity memory typified by (Ferroelectric Random Access Memory) and a high-performance element typified by MFS and MFIS type transistors have been demanded. FeRAM
Ferroelectric materials such as PZT are used as the insulating film in the MFS type transistor, the MFS type transistor, and the MFIS type transistor, but in order to realize a DRAM having a storage capacity of 1 gigabit class or more, the charge is accumulated in the DRAM. As a capacitor material to be used, Ba-Sr-Ti-0
It has become necessary to use high-ferroelectric materials such as those based on BST and Pb-Zr-Ti-O (PZT).

On the other hand, in a DRAM which requires a high degree of integration, it is necessary to reduce the size of the capacitor in order to miniaturize the device. Therefore, measures such as making the capacitance part cylindrical and forming minute irregularities on the surface of the storage node to reduce the size of the capacitor while increasing the area of the capacitance film to secure the accumulated charge amount have been made. There is. Further, miniaturization is also required for FeRAM, MFS type transistor, MFIS type transistor and the like.

Therefore, when forming a high-ferroelectric material film, a CVD method which can form a fine step with good coverage is mainly used, and in order to obtain good dielectric characteristics by the CVD method. Research and development is active.

In the CVD method used for forming BST or PZT, an organometallic complex containing a metal element forming the BST film or PZT film is used as a raw material, and the organometallic complex is converted into butyl acetate or THF (tetrahydrofuran). There is a thermal CVD method in which it is dissolved in a polar solvent such as), vaporized and then introduced into the reaction chamber to cause a reaction such as decomposition or chemical combination on the heated substrate. At that time, there is also a plasma CVD method in which plasma is generated in the reaction chamber to assist the reaction on the substrate with the plasma. Further, in the thermal CVD method or the plasma CVD method, in order to mix a plurality of raw materials in a predetermined ratio, a method of vaporizing after mixing a plurality of organic metal complex solutions, or a method of vaporizing each organic metal complex solution and a solvent After that, a method of mixing at a predetermined ratio is adopted.

For example, in the film forming process of the BST CVD method, as raw materials, Ba (DPM) ₂ , Sr (D
PM) ₂ , Ti (O-iPr) ₂ (DPM) ₂ 3
Using two organometallic complexes (where the DPM group is dipivaloylmethanate), these raw materials were each dissolved in butyl acetate at room temperature, mixed at a specified weight ratio, and then heated to approximately 220 ° C. After being introduced into the vaporizer and vaporized, the three vaporized metal complexes are introduced into the reaction chamber. In the reaction chamber, the substrate is 400 ° C to 7 ° C.
It is heated to a temperature of about 00 ° C., and the vaporized three metal complexes are reacted on the substrate to form a BST film.

FIG. 6 is a diagram showing a molecular state when each organometallic complex is reacted in a reaction chamber. As shown in the figure,
In general, the organometallic complex is more likely to bond with each other to form a multimer than to remain as a monomer, so that the vaporization temperature is likely to change or decompose. Therefore, in order to prevent the binding between the organometallic complexes, by coordinating what is called an adduct such as a tetraglyme group, a multimer such as a dimer or trimer is formed, which causes steric hindrance and prevents the multimerization. A lot is done.

[0008]

However, it has been found that a large amount of carbon compounds remains in the film formed by the CVD method using the organometallic complex as a raw material. This residual carbon compound has not been a serious problem at present in memories such as DRAM and FeRAM. However, the presence of carbon compounds in the dielectric film affects electrical properties such as dielectric properties. Further, when the remaining carbon compound becomes mobile ions, it moves according to the electric field and segregates with the operation of the capacitor, which may reduce the reliability. Therefore, in the DRAM and the FeRAM as well, there is a concern that the further miniaturization of the memory cell may cause a defect. In particular, in the MFS type transistor and the MFIS type transistor, there is a possibility that malfunctions due to mobile ions will occur, and there is a concern that reliability may deteriorate.

An object of the present invention is to form a film by a CVD method using an organometallic complex or an organometallic raw material.
It is intended to solve the above-mentioned inconvenience by taking measures capable of suppressing the amount of carbon compounds in the film.

[0010]

Manufacturing of the semiconductor device of the present invention
The manufacturing method is an invitation to function as an information holding unit on the semiconductor substrate.
Manufacture of semiconductor devices with memory cells equipped with electrical film
Method, ferroelectric acting as information holder on semiconductor substrate
Method for manufacturing semiconductor device having memory cell having body film
Method, on the semiconductor substrate as the conductivity control part of the semiconductor substrate surface
Semiconductor device with an element equipped with a ferroelectric film that functions as
The manufacturing method of the film is as follows.
I used it.

The method for forming the first film is as follows:Ba (DPM)
₂ , Sr (DPM) ₂ And Ti (O-iPr) ₂ (DP
M) ₂ The step of dissolving the raw material containing
(A), the above non-polar solvent and the starting material in a gaseous state
Or liquid state, and introduce it into the reaction chamber where the substrate is installed.
Introducing step (b), the above raw materials are chemically
Allow the reaction to occur on the substrateDielectric film or ferroelectric filmTo
Forming step (c).

According to this method, when a film is formed by the reaction of the raw material, the non-polar solvent has a large molecular weight which is coordinated around the organic metal by electrical interaction with the organic metal like a polar group of the polar solvent. There are few organic molecular groups having That is, it is considered that a carbon compound which becomes a mobile ion is taken into the film due to H ₂ O generated during film formation and a polar group generated by decomposition of the polar solvent in the conventional method. Is. Therefore, by using a non-polar solvent, the amount of carbon compounds incorporated into the film is reduced, and the content of carbon compounds that become mobile ions in the film due to the incorporation of solvent molecules into the film is reduced. You can

[0013]FirstThe method of forming the film of 2 isBa (DPM)
₂ , Sr (DPM) ₂ And Ti (O-iPr) ₂ (DP
M) ₂ Step of dissolving a raw material containing
(A) and the polar solvent and the raw material are in a gaseous state.
Liquid state and put it in the reaction chamber where the substrate is installed.
Step (b) and chemical reaction of the above raw materials on the substrate
Wake up on the boardFerroelectric filmForming steps
(C) and to make the substrate surface polar.
Is a method of controlling the amount of carbon compounds mixed in the film.
It

[0014] By this method, when the polar solvent is decomposed on the substrate surface, the polarity of the substrate surface, ing can be controlled the amount of carbon compounds contained in the ferroelectric film.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) -Thin Film Forming Apparatus and Thin Film Forming Method-Fig. 1 is a thin film forming method for carrying out the film forming method in the first and second embodiments of the present invention. It is a figure which shows a device roughly. This thin film forming apparatus has a structure suitable for using a method called a solution vaporization method.

As shown in FIG. 1, this thin film forming apparatus is
A reaction chamber 3 for performing CVD, a vaporizer 5 for supplying a raw material gas to the reaction chamber, a liquid pump 6 for forcibly feeding a mixture of raw material solutions into the vaporizer 5, and a mixture of each raw material solution. A mixing device 7 for storing the raw material solution and three solution tanks 8 for individually storing the raw material solutions are provided. A heating stage 2 for heating the substrate 1 is arranged inside the reaction chamber 3. Each solution tank 8 stores an organic metal complex as a raw material dissolved in a solvent (= raw material solution), and one solution tank 8 is provided for each raw material solution. The respective raw material solutions stored in the solution tank 8 are mixed at an appropriate mixing ratio by the mixer 7, and then the mixture is extruded to the vaporizer 5 by the liquid pump 6, and the respective raw materials are vaporized by the vaporizer 5. It Then, the vaporized source gas is introduced into the reaction chamber 3 through the inlet 4 provided at the upper part of the reaction chamber 3.

For example, when a BST thin film is formed on the substrate 1, Ba (DPM) ₂ , Sr (DP
M) ₂ and Ti (O-iPr) ₂ (DPM) ₂ are used, and the solvent is a toluene solvent which is a nonpolar solvent. This embodiment is characterized in that this non-polar solvent is used as a solvent for dissolving the raw material (organic metal or organometallic complex). That is, three solution tanks, a Ba-containing solution tank, an Sr-containing solution tank, and a Ti-containing solution tank, are prepared, and each solution tank 8 has:
A solution prepared by dissolving each of the above raw materials in a toluene solvent is enclosed.

The term "nonpolar solvent" as used herein means that the D value (dipolar moment) is 0.5D or less, preferably 0.
1D or less. For example, in the case of toluene, its D
The value is 0.37D. Therefore, benzene (0.0
D) and heptane (0.0D), octane (0.0D),
Hexane (0.08D) and the like also correspond to the nonpolar solvent referred to here, and these may be used.

In order to form a thin film, first, the raw material solutions in the respective solution tanks 8 are pressurized with N ₂ at a pressure according to the mixing ratio.
The raw material solutions are pressurized by gas and flowed through the lines, and the raw material solutions are mixed in the mixer 7 at a predetermined ratio.
Then, the mixed solution is forcibly fed into the vaporizer 5 heated to 220 ° C. while controlling the flow rate by the liquid pump 6. In the vaporizer 5, the raw material and the toluene solvent in the introduced mixed solution are simultaneously gasified and become a raw material gas. This source gas is introduced into the reaction chamber 3 through the inlet 4, reaches the substrate 1 on the heating stage 2 heated to about 450 ° C. to 600 ° C., and the source gases are separated from each other on the surface of the substrate 1. Due to the gas phase reaction, a dielectric film is formed on the surface of the substrate 1.

In this embodiment, the method of vaporizing the mixed solution by the vaporizer 5 and then introducing it into the reaction chamber 3 is adopted. However, a method of atomizing the mixed solution and introducing it into the reaction chamber is used. May be adopted. In that case, a sprayer is provided in place of the vaporizer, and the mixed solution is introduced into the reaction chamber in the state of a mist liquid, adheres on the surface of the substrate 1 in a mist state, and then vaporized on the substrate 1, A film is formed on the surface of the substrate 1 by reacting these in a gas phase.

Next, the effect on the carbon compound remaining in the film when a non-polar solvent is used will be described below.

-Experiments on the conventional method using a polar solvent-First, an organometallic complex represented by a molecular structure as shown in FIG. 6, Ba (DPM) ₂ -tetraglyme, Sr (DP)
M) ₂ tetraglyme, Ti (O-iPr) ₂ (DP
The case where M) ₂ is used as a raw material and butyl acetate, which is a polar solvent that has been conventionally used, is used as a solvent will be described.

The inventors of the present invention prepared a comparative sample by the conventional method according to the following procedure. A raw material solution is prepared by dissolving the above-mentioned organometallic complex in butyl acetate which is a polar solvent, and the raw material solutions are mixed at a certain ratio at room temperature. And
This mixed solution is introduced into a vaporizer heated to 230 ° C. to vaporize the mixed solution, and then a raw material gas is introduced into the reaction chamber. Then, in the reaction chamber, the substrate temperature is set to 450 ° C. to 70 ° C.
The temperature was arbitrarily set within the range of 0 ° C., and the gas phase reaction of the raw material gas was caused to occur on the heated substrate to form the BST film on the substrate. As the substrate, a SiO ₂ film and a Ti
A film in which an O ₂ film and a Pt film are sequentially deposited is used.

Here, the present inventors have conducted a thermal desorption analysis (TD) in order to measure the amount of residual carbon compounds in the BST film.
S) degassing analysis of BST film in vacuum and secondary ion mass spectrometry (TOF-SI) using time-of-flight measurement
The carbon-containing ions in the BST film were analyzed by MS).

FIG. 2 is a diagram showing degassing analysis data by TDS of a BST film prepared by a conventional method. Figure 2
In, the horizontal axis represents the temperature (° C.) of the sample at the time of analysis, and the vertical axis represents the desorption amount of CO (m / e = 28), which is considered to be due to the residual carbon compound in the BST film.
Here, data of a BST film sample formed under the condition that the substrate temperature is 450 ° C. and a sample of the BST film formed under the condition that the substrate temperature is 600 ° C. are representatively shown. As shown in the same figure, from the TDS analysis, the desorption peak of the substance CO was observed from around 600 ° C. in both the sample at the film forming temperature of 450 ° C. Desorption is observed, 700 ° C
Up to the desorption of CO was observed. In addition, of the two samples, the sample having a film forming temperature of 450 ° C. has a film forming temperature of 6
It was found that the desorption amount of CO was larger than that of the sample at 00 ° C. That is, it was found that the BST film formed at a low temperature has a larger amount of released CO than the BST film formed at a high temperature. Further, analysis of all the substances desorbed from the BST film revealed that most of them were CO.

In analyzing the residual carbon compound in the BST film by TOF-SIMS, the present inventors have
We have gained new knowledge.

FIG. 3 shows TOF-SIMS analysis data of a BST film formed by a conventional method using a polar solvent. In the figure, the horizontal axis represents the ion species, and the vertical axis represents the count amount of ions obtained as a result of the analysis. The sample used for measurement had a film formation temperature of 4
Untreated (As depo.) At 50 ℃, film formation temperature is 600
Untreated (As depo.) At ℃, film formation temperature of 450 ℃, annealed in N ₂ gas at 700 ℃, film formation temperature of 600 ℃, annealed at 700 ℃ in N ₂ gas,
The film formation temperature was 600 ° C., the sample was annealed at 700 ° C. in O ₂ gas, and the analysis data of five kinds of samples in total are shown. Here, the measurement results for positive ion species are shown. As a result, especially C ₂
Ions with large molecular weight such as H ₃ , C ₅ H ₅ , C ₄ H ₇ , and C ₆ H ₉ were detected as masses. This means that the molecules may be decomposed to some extent when the molecules are detected in the mass analysis. Therefore, in the actual BST film, the carbon compound may remain in a considerably large molecule state. It turned out.

Considering the number of carbon atoms, tetraglyme adduct, butyl acetate which is a polar solvent, DPM group and the like may be the source of the large molecular weight carbon compound. Here, the large amounts introduced into the reaction chamber are butyl acetate and tetraglyme adduct, and further TOF-S
In the IMS analysis, in addition to the ions shown in FIG. 4,
Ions that are considered to be caused by acetate ions, such as negative ions HCOO, have also been detected. The boiling point of tetraglyme used as an adduct is 275.3 ° C.
And high. On the other hand, the boiling point of butyl acetate is 118 ° C., but it is considered that the molecule is stable. Judging from the above, it is considered that many carbon compounds are taken into the BST film from a polar solvent (butyl acetate) or an adduct.

Further, from the results of TOF-SIMS, it was found that the sample having a lower film formation temperature had a larger amount of the carbon compound incorporated into the BST film, and the reduction rate of the ionic species was larger due to the heat treatment after the film formation. I understand. In particular, with respect to the sample subjected to the heat treatment after the film formation, the reduction rate of the large molecular weight ionic species is large. It was found that when the film formation temperature was 600 ° C. or lower, the final residual amount of the carbon compound in the BST film did not change much depending on the film formation temperature. In addition, a sample formed at a film forming temperature of 450 ° C.,
X-ray diffraction (X
From the evaluation of crystallinity by RD), it was found that the sample at the film forming temperature of 450 ° C. was in an amorphous state and the sample at the film forming temperature of 600 ° C. was crystallized.

It can be considered that the above facts apply not only to the BST film but also to the dielectric film formed by using the organometallic complex or the organometal in general. Therefore, based on the above facts, the present inventors have found that the main causative substance of the carbon compound remaining in the dielectric film formed by using the organic metal complex or the organic metal by the conventional method is the polar solvent. Therefore, we conducted experiments to support this estimation.

-Experiment on formation of BST film using non-polar solvent-FIG. 4 shows TOF-SIMS of BST film formed by the method of the present embodiment using n-hexane as a non-polar solvent.
It is a figure which shows the analysis data by. In the figure, the horizontal axis represents the ion species, and the vertical axis represents the ion intensity ratio normalized by the data of the sample of the conventional example shown in FIG. The sample of the present embodiment for which the data shown in FIG. 4 was obtained had a substrate temperature of 600 ° C. and a gas pressure of 5 in the reaction chamber.
Torr (about 666.5 Pa) and 25% O in the reaction chamber
₂ gas was introduced to form a BST film, and the BST film was not annealed. The method of generating the raw material gas is as described above. Therefore, the ionic strength ratio shown on the vertical axis of FIG. 4 is the data shown by Δ in the data shown in FIG. 3, that is, the ion count of the untreated sample (As depo.) It is a value calculated as "1". Note that, in FIG. 4, data on ion species such as C, which are generated from portions other than the BST film and whose measurement accuracy is not guaranteed, is omitted.

As shown in the figure, the residual carbon compound in the BST film of the sample formed by the method of this embodiment is considerably smaller than the residual carbon compound in the BST film of the conventional example. That is, it is supported that the residual carbon compound in the dielectric film formed by using the organic metal complex or the organic metal can be reduced by the film forming method of the present embodiment.

-Reduction of residual carbon compound in the present embodiment-Next, as in the present embodiment, by using a non-polar solvent as a solvent for dissolving the organometallic complex or the organometal, the carbon compound is introduced into the film. The mechanism by which the uptake amount of is reduced is described.

As described above, among the negative ion species detected by TOF-SIMS, HCOO is contained in butyl acetate. It is presumed that the formation of a dielectric film such as a BST film is intricately entangled with each other in the decomposition of a solvent, an organometallic complex (or an organometal), and a gas phase reaction, and its elementary reaction is completely clarified. Not not. But,
Considering the results of the crystal evaluation by XRD together, it is presumed that the manner in which the carbon compound is incorporated into the BST film in the conventional forming method is as follows.

Each organometallic complex was dissolved in butyl acetate as a polar solvent to prepare a raw material solution, and the raw material solution was mixed in a liquid state (normal temperature) at a predetermined ratio, and the mixed solution was heated to 230 ° C. It is introduced into a vaporizer and is vaporized into a raw material gas. At this time, the organometallic complex with an adduct (or organometal), the adduct simple substance, and the solvent are vaporized. These vaporized source molecules are introduced into the reaction chamber and undergo a gas phase reaction with each other on the surface of the substrate. The reaction elementary process at this time is unknown, but at the same time as the formation of BST,
It is presumed that each raw material molecule is decomposed.

From the result of XRD, it is known that the BST crystal is not formed at 450 ° C. and the crystal is synthesized at the growth of 600 ° C. Further, from the TDS and TOF-SIMS analysis results, desorption of carbon in the BST film occurs from around 600 ° C. regardless of the film formation temperature. From these facts, it is considered that the carbon residue in the BST film is involved in the BST crystal formation process on the substrate.
It can be classified as one that is not involved.

For example, as the factors involved in the process of forming BST crystals, there are one that is caused by the DPM complex and one that is caused by the adduct coordinated to the metal atom. When a polar solvent is used, the polar group in the polar solvent makes an electrical interaction with the metal complex of the organometallic complex and coordinates like an adduct. As a result, polar groups in the polar solvent are incorporated into the BST film as the BST crystal is formed.

On the other hand, in the film forming method of this embodiment, the solvent is a nonpolar solvent such as a toluene solvent. In this non-polar solvent, there are almost no groups that coordinate with the organometallic complex by an electrical interaction, so the amount of carbon compounds incorporated into the dielectric film is reduced.

Further, the carbon compound taken in in the process other than the crystal formation process changes its residual amount depending on whether the heat and the atmosphere are oxidizing, that is, depending on how much it burns. Therefore, in order to reduce the residual amount of this type of carbon compound, it is effective to reduce the molecular weight of the carbon ion species taken in during film formation. That is, it is desirable that the non-polar solvent has a small molecular weight. For example, as the aromatic hydrocarbon solvent, toluene is preferable to xylene, and benzene is preferable to toluene. Also,
In the straight chain hydrocarbon solvent, heptane is preferable to octane, and hexane is preferable to heptane. Furthermore, it is desirable that the halogenated hydrocarbon solvent has a low molecular weight and a small polar moment (polarity) such as carbon tetrachloride. It should be noted that, based on the result of TOF-SIMS, fluorine and chlorine derived from halogenated hydrocarbon can be desorbed relatively easily by heat treatment even if they remain.

When the BST film is formed by the above-mentioned procedure, especially when the substrate temperature is set to about 650 ° C. or lower, a region called “Haze” having a non-uniform composition appears in the formed BST film. However, it is known that the appearance of this region deteriorates the leak characteristics of the BST film. Therefore,
Although measures have been taken to suppress the generation of Haze by adjusting process parameters such as film formation pressure, raw material concentration, gas flow rate, etc., a fundamental solution has not yet been discovered.

Here, the present inventors speculate that the reaction of the Ti raw material having an alkoxide group with a solvent is the cause of Haze. Therefore, it was found that this Haze can be almost extinguished by using a non-polar solvent such as a hydrocarbon that is less aggressive to the alkoxide group as in the method of the present embodiment. That is, especially when forming the BST film, not only the reduction of residual compound carbon but also the reduction of Ha
The occurrence of ze can be suppressed.

-Application to Semiconductor Device Manufacturing Method of This Embodiment- In the DRAM manufacturing process, the above-mentioned thin film forming method can be used when forming the charge storage capacitance insulating film of the memory cell. As a result, it is possible to reduce the residual carbon compound that affects the dielectric characteristics of the capacitance insulating film, so that a highly reliable DRAM can be obtained.

In the FeRAM manufacturing process, a ferroelectric capacitor for storing polarization information in the memory cell, such as SrBi ₂ Ta ₂ O ₉ or Pb (Zr _x Ti _1-x ) O.
_The above-mentioned thin film forming method can be used when forming a ferroelectric capacitor using a ferroelectric substance such as ₃ . As a result, it is possible to obtain an FeRAM having excellent reliability, similar to the DRAM.

In the manufacturing process of the MFS type transistor, the above thin film forming method can be used when forming the ferroelectric gate insulating film formed between the semiconductor substrate and the gate electrode. As a result, the carbon compound remaining in the ferroelectric gate insulating film can be reduced, so that not only the adverse effect on the dielectric characteristics can be prevented but also the malfunction of the transistor due to the residual carbon compound becoming mobile ions. Can be suppressed, and a highly reliable MFS transistor can be obtained.

In the case of the MFIS type transistor, at the time of forming the ferroelectric gate insulating film interposed between the semiconductor substrate and the gate electrode, and at the time of forming the insulating film interposed between the ferroelectric film and the semiconductor substrate. In this case, the above thin film forming method can be used. As a result, as in the case of the MFS type transistor, a highly reliable MFIS type transistor can be obtained.

In the present invention, formation of a Ru metal film using ORu (DPM) ₃ and (CH ₃ C ₅ H ₄ ) (CH
₃ ) The above-mentioned effects can also be exhibited by applying it to the formation of a Pt film using ₃ Pt.

Second Embodiment In this embodiment, a method of controlling the amount or type of carbon compound incorporated in the dielectric film by treating the surface of the substrate will be described. The treatment of the substrate surface is a treatment for controlling the charged state of the substrate surface or introducing a hydrophilic group or a hydrophobic group into the substrate surface. Also in this embodiment, the apparatus shown in FIG. 1 can be used as the thin film forming apparatus.

FIG. 5 shows the results of TOF-SIMS analysis of BST films formed using a polar solvent when the surface layer of the substrate is a Pt layer and when the surface layer of the substrate is a Si layer. FIG. In the figure, the horizontal axis represents the ion species and the vertical axis represents the ion intensity ratio. here,
The sample that was subjected to TOF-SIMS analysis was untreated (As dep
o.) formed on the Pt layer at a film forming temperature of 600 ° C. and then annealed at 650 ° C., formed on the Pt layer at a film forming temperature of 600 ° C. and then 700 ° C. in N ₂ gas Annealed, formed on the Pt layer at a film forming temperature of 600 ° C. and then annealed at 700 ° C. in O ₂ gas, Si
Unprocessed (As d
epo.) and the analytical data for a total of 5 samples are shown.

As shown in the figure, from the result of TOF-SIMS analysis, even if the BST film was formed at the same 600 ° C., the BST film formed on the Pt layer was formed on the Si layer. It is estimated that it contains more carbon compounds than the prepared BST film.

Here, the Si layer is hydrophilic because a natural oxide film is formed on the surface thereof, but the Pt layer is not hydrophilic and is not hydrophilic because the oxide film is not formed on the surface in a natural state. It is oily. Further, from the result shown in FIG. 5, S
It was found that the BST film formed on the i layer had a particularly low hydrocarbon content compared to the BST film formed on Pt. From this, when the lipophilic Pt layer is the surface layer, the adsorption amount of the hydrocarbon, which is the lipophilic group, on the Pt layer increases, and as a result, P
It can be seen that the amount of carbon compound incorporated in the BST film formed on the t layer increases. On the other hand, the content of hydrophilic groups detected as negative ions in TOF-SIMS was not so different between the BST film formed on the Si layer and the BST film formed on the Pt layer. From the above, it can be seen that making the surface of the substrate hydrophilic is effective for reducing the amount of the carbon compound having a lipophilic group incorporated into the BST film.

Further, even in a substrate having a lipophilic Pt layer or the like as a surface layer, an outermost surface layer of the substrate is made hydrophilic by further forming an oxide film (Pt—O) on the surface of the Pt layer. The same effect can be obtained by changing to.

Here, forming an oxide film (Pt-O) to make the Pt layer of the substrate hydrophilic makes the surface layer of the substrate charged at the same time. The Si layer, which is a semiconductor material, is in a charged state, but the Pt layer, which is a metal material, is not in a charged state. Therefore, the effect of the present embodiment can also be obtained by controlling the charged state of the substrate surface.

As described above, the thin film forming method of this embodiment is characterized in that the film formation is performed by controlling the charged state or hydrophilicity / hydrophobicity of the substrate surface. Then, by controlling the charged state or the hydrophilicity / hydrophobicity of the substrate surface, the kind of the carbon compound taken into the dielectric film is changed and the amount of the carbon compound can be controlled.

-Application to Semiconductor Device Manufacturing Method of This Embodiment- In the DRAM manufacturing process, the above-described thin film forming method can be used when forming the charge storage capacitance insulating film of the memory cell. As a result, it is possible to reduce the residual carbon compound that affects the dielectric characteristics of the capacitance insulating film, so that a highly reliable DRAM can be obtained.

In the FeRAM manufacturing process, a ferroelectric capacitor such as SrBi ₂ Ta ₂ O ₉ or Pb (Zr _x Ti _1-x ) O for storing polarization information in the memory cell is used.
_The above-mentioned thin film forming method can be used when forming a ferroelectric capacitor using a ferroelectric substance such as ₃ . As a result, it is possible to obtain an FeRAM having excellent reliability, similar to the DRAM.

In the manufacturing process of the MFS type transistor, the above thin film forming method can be used when forming the ferroelectric gate insulating film formed between the semiconductor substrate and the gate electrode. As a result, the carbon compound remaining in the ferroelectric gate insulating film can be reduced, so that not only the adverse effect on the dielectric characteristics can be prevented but also the malfunction of the transistor due to the residual carbon compound becoming mobile ions. Can be suppressed, and a highly reliable MFS transistor can be obtained.

In the case of the MFIS type transistor, at the time of forming the ferroelectric gate insulating film interposed between the semiconductor substrate and the gate electrode, and at the time of forming the insulating film interposed between the ferroelectric film and the semiconductor substrate. In this case, the above thin film forming method can be used. As a result, as in the case of the MFS type transistor, a highly reliable MFIS type transistor can be obtained.

[0058]

According to the present invention, by using a non-polar solvent, the electrical interaction between the organometallic complex and the solvent can be reduced, and the amount of carbon taken into the film during film formation can be reduced. Becomes Further, by making the surface state of the substrate hydrophilic, it is possible to reduce and control the amount of the lipophilic group carbon compound taken into the film.

[0059] As a result, it is possible to obtain a semiconductor device of the memory device or transistor or the like which is excellent in reliability.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a thin film forming apparatus for carrying out a thin film forming method according to an embodiment of the present invention.

FIG. 2 TDS for evaluating carbon desorption amount of BST film
It is a figure which shows analytical data.

FIG. 3 is a diagram showing TOF-SIMS analysis data for evaluating the amount of residual carbon compounds in a BST film.

FIG. 4 is a diagram showing data for comparing the residual compound amount of the BST film using the non-polar solvent according to the present invention with the residual compound amount of the BST film according to the conventional method.

FIG. 5 is a diagram showing TOF-SIMS analysis data for explaining the difference in the carbon incorporation amount in the film depending on the type of substrate.

FIG. 6 is a diagram showing molecular structures of a raw material and a solvent used in a conventional film forming method.

[Explanation of symbols]

1 substrate 2 heating stage 3 reaction chamber 4 Vaporized gas inlet 5 vaporizer 6 Liquid pump 7 mixer 8 solution tanks

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) C23C 16/00-16/56 H01L 21/316

Claims (3)

(57) [Claims] 1. A function as an information holding unit on a semiconductor substrate
Device having a memory cell having a dielectric film
The manufacturing method ofBa (DPM) ₂ , Sr (DPM) ₂ And Ti (O-i
Pr) ₂ (DPM) ₂ Dissolve raw material containing
Step (a) to make the solution, The non-polar solvent and the raw material are in a gaseous state or a liquid state.
State, the step of introducing the substrate into the reaction chamber where the substrate is installed is performed.
(B), On the substrate, the above raw materials are allowed to undergo a chemical reaction on the substrate.
And (c) forming the above-mentioned dielectric film on the semiconductor.
Body device manufacturing method. 2. A function as an information storage unit on a semiconductor substrate
Semiconductor device with a memory cell equipped with a ferroelectric film
A method of manufacturing a device,Ba (DPM) ₂ , Sr (DPM) ₂ And Ti (O-i
Pr) ₂ (DPM) ₂ Dissolve raw material containing
Step (a) to make the solution, The non-polar solvent and the raw material are in a gaseous state or a liquid state.
State, the step of introducing the substrate into the reaction chamber where the substrate is installed is performed.
(B), On the substrate, the above raw materials are allowed to undergo a chemical reaction on the substrate.
A step (c) of forming the ferroelectric film
A method for manufacturing a conductor device. 3. Conduction on the surface of the semiconductor substrate on the semiconductor substrate
Equipped with an element equipped with a ferroelectric film that functions as a rate controller
A method of manufacturing a semiconductor device, comprising:Ba (DPM) ₂ , Sr (DPM) ₂ And Ti (O-i
Pr) ₂ (DPM) ₂ Dissolve raw material containing
Step (a) to make the solution, The non-polar solvent and the raw material are in a gaseous state or a liquid state.
State, the step of introducing the substrate into the reaction chamber where the substrate is installed is performed.
(B), On the substrate, the above raw materials are allowed to undergo a chemical reaction on the substrate.
A step (c) of forming the ferroelectric film
A method for manufacturing a conductor device.