JPH1022467A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a semiconductor device which has a capacitance portion having a high capacitance value and held in an electrically insulated state from adjacent elements without reducing the effective capacitance value and without causing deterioration in transistor characteristics, and manufacture thereof. SOLUTION: An interlayer film 2 is formed on a silicon substrate 1, and a contact hole 3 is opened in the interlayer film. A barrier film 7 of titanium nitride is formed in the contact hole, and a lower electrode 9 is formed thereon. After recess and protrusion are formed on the surface of the lower electrode 9, a capacitance insulating film 10 is formed and an upper electrode 11 is formed thereon. The effective capacitance value may be increased by the surface recess and protrusion of the lower electrode and by increasing the impurity density thereof. Since impurity is prevented by the barrier film 7 from being diffused to a diffusion layer, deterioration in transistor characteristics may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a stacked structure having a capacitance portion, and more particularly to a semiconductor device having a reduced capacitance portion and a large capacitance, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device such as a DRAM, it is necessary to provide a capacitance portion such as a stacked capacitor or a trench capacitor. Among them, the stacked capacitor is
Usually, it is formed as follows. That is, after growing a polysilicon film on an insulating film provided on a semiconductor substrate, an impurity such as phosphorus is introduced into the polysilicon film, and the polysilicon film is formed by a plasma etching technique using a photoresist film. A lower electrode is formed by patterning the silicon film. Next, a capacitor insulating film is formed on the lower electrode, and an upper electrode is formed on the capacitor insulating film by using the same method as the above-described method of forming the lower electrode.

However, in a stacked capacitor manufactured by such a manufacturing method, the capacitance value is limited by the facing area between the lower electrode and the upper electrode. Therefore, 64M
As device miniaturization advances like a bit DRAM, the occupied area of each of the upper and lower electrodes in the capacitance section also becomes smaller accordingly, and it is not possible to simply form electrodes with a polysilicon film as described above. It is becoming difficult to secure the required capacity. Therefore, a method of providing irregularities on the surface of the lower electrode has been proposed as a means for effectively increasing the electrode area without increasing the occupied area of the capacitance section.

For example, Japanese Unexamined Patent Publication No. 5-304273 discloses that the surface area of a lower electrode made of an amorphous silicon film is made uneven to increase the surface area of the lower electrode as compared with its planar area. , The so-called HSG (Hemi-S
sphere-Grein) technology is disclosed. FIG.
FIG. 1 shows a process sectional view in the case of forming a capacitance portion using this conventional technique. First, as shown in FIG. 9A, a silicon oxide film 22 is formed on a silicon substrate 21, and a contact hole 23 is formed using a normal lithography technique and a dry etching technique. Next, as shown in FIG. 9B, phosphorus (P) is formed by using a CVD (chemical vapor deposition) method.
The doped amorphous silicon film 24 is formed to a thickness of 200 to 500 n.
grow to m. As growth conditions in this case, for example,
Reaction gas Si ₂ H ₆ or SiH ₄ and PH ₃ , pressure 0.1
２2 Torr and a growth temperature of 600 to 500 ° C. Then, patterning is performed in the shape of the lower electrode using a normal lithography technique and a dry etching technique.

[0005] Thereafter, as shown in FIG. 9 (c), Si ₂ H
By flowing a gas containing silicon (Si) such as ₆ and heating, a spherical silicon grain grows on the surface of the amorphous silicon to form irregularities, and the surface area is more than twice as large as that of normal polysilicon. Is formed. The conditions at this time are as follows: a temperature of 540 to 650 ° C. and a pressure of 10 ⁻³ Torr.
r or less, the Si ₂ H ₆ gas is 1 to 20 sccm at 1 to 30 sccm.
What is necessary is just to heat for 2 minutes, and then heat for 1 to 10 minutes. Then, as shown in FIG. 9D, a capacitance insulating film 26 made of a silicon oxide film and a silicon nitride film is formed on the surface of the lower electrode 25, and then a polysilicon film is formed by a normal method. After the introduction of impurities such as phosphorus, the upper electrode 27 is formed using ordinary lithography and dry etching techniques.
Is performed.

[0006]

However, in this conventional technique, the surface of the lower electrode 25 is made HSG to increase the surface area of the lower electrode. However, since the silicon atoms move during the HSG processing, the HSG is formed. After performing the above, phosphorus (P) which is an impurity is hardly contained in the silicon grains on the surface of the lower electrode. Since the silicon grain shape is constricted even in the subsequent heat treatment, phosphorus has a property of hardly diffusing. For this reason, after the formation of the capacitance portion, a depletion layer extends on the lower electrode side due to the CV characteristics of the capacitance film, and a problem occurs in that the effective capacitance value decreases. To solve this problem, it is conceivable to increase the phosphorus concentration in the lower electrode before HSG conversion, that is, in the phosphorus-doped amorphous silicon. The P concentration required to prevent the effective capacitance value from decreasing is 10
²⁰ atom / cm ³ or more. However, when the lower electrode having such a high P concentration is used, phosphorus diffuses from the lower electrode 25 into the diffusion layer in the silicon substrate 21 in the heat treatment step after the HSG treatment, thereby deteriorating the transistor characteristics and causing a problem with the adjacent element. A problem arises in that the electrical insulation of the substrate cannot be maintained. Since the effective capacitance value does not decrease and the transistor characteristics do not deteriorate and the electrical insulation with the adjacent element is maintained, the phosphorus concentration is in a very narrow range, which is not practical.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor device having a high-capacitance value, an effective capacitance value is not reduced, a transistor characteristic is not degraded, and an electric insulation with an adjacent element is maintained. And a method of manufacturing the same.

[0008]

According to the present invention, there is provided a semiconductor device comprising: an insulating film formed on a surface of a semiconductor substrate; a contact hole formed in the insulating film; In a semiconductor device including a lower electrode to be connected, a capacitor insulating film formed on a surface of the lower electrode, and a capacitor portion formed of an upper electrode formed on the capacitor insulating film, Are characterized in that unevenness is formed, and a barrier film for preventing the transmission of impurities exists between the lower electrode and the diffusion layer. Here, the irregularities on the surface of the lower electrode are made of HSG silicon grains. Preferably, the barrier film is made of titanium nitride.

The manufacturing method according to the present invention comprises the steps of: opening a contact hole reaching an diffusion layer formed in the semiconductor substrate in an interlayer film formed on the semiconductor substrate; and forming at least a contact hole in the contact hole on the diffusion layer. A step of forming a titanium nitride film as a barrier film, a step of forming a lower electrode on the interlayer film including the contact hole, a step of forming irregularities on the surface of the lower electrode, Forming a capacitive insulating film; and forming an upper electrode on the capacitive insulating film.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are sectional views showing a semiconductor device according to the first embodiment of the present invention in the order of manufacturing steps. First, as shown in FIG. 1A, a silicon oxide film 2 is formed on a silicon substrate 1 and a contact hole 3 is formed in the silicon oxide film 2 of the interlayer film using a normal photolithography technique and a dry etching technique. I do. Thereafter, as shown in FIG. 1B, titanium (T
i) The film 4 is formed by sputtering or CVD. Next, as shown in FIG. 1C, heat treatment is performed at 500 to 700 ° C. in an atmosphere of nitrogen, ammonia, or a mixed gas thereof. The titanium film on the diffusion layer is mainly a titanium silicide film 5, and the titanium film on the silicon oxide film as the interlayer film is a titanium nitride film 6. Then, as shown in FIG.
The titanium nitride film 6 is selectively removed by dipping in an aqueous solution containing ammonia and hydrogen peroxide at room temperature to about 100 ° C.
Instead of the aqueous solution containing ammonia and hydrogen peroxide, an aqueous solution containing sulfuric acid and hydrogen peroxide at about 60 ° C. to 100 ° C. may be used. At this time, the thin titanium nitride film formed on the surface of the titanium silicide film 5 is removed, but the titanium silicide film 5 remains in the contact hole 3 without being etched.

Next, as shown in FIG.
700 to 10 in an ammonia or mixed gas atmosphere thereof
Heat treatment is performed at 00 ° C. to nitride the titanium silicide film 5. By the nitriding treatment, the surface of the titanium silicide film 5 or the entire titanium silicide film is mainly
However, silicon is also included. As shown in FIG.
Phosphorus (P) -doped amorphous silicon film 8 using VD method
Is grown to a thickness of 200 to 500 nm. As growth conditions in this case, for example, a reaction gas Si ₂ H ₆ or SiH
₄ and PH ₃ , pressure 0.1-2 Torr, growth temperature 600
To 500 ° C., and the phosphorus concentration in the amorphous silicon film is 1
From 5 × 10 ²⁰ atom / cm ³ . Further, the lower electrode 8 is formed by patterning the amorphous silicon film 8 using a normal photolithography technique and a dry etching technique.

Next, as shown in FIG. 2C, after forming an amorphous silicon film in the same manner as in the prior art, the surface is made uneven by HSG to increase the surface area of the lower electrode. For example, the conditions at this time are as follows: a temperature of 540 to 650 ° C., a pressure of 10 ⁻³ Torr or less, and a Si ₂ H ₆ gas of 20 to 30 seconds.
It may be flowed at ccm for 1 to 2 minutes, and then heated for 1 to 10 minutes. As a result, spherical silicon grains are grown on the surface and irregularities are formed on the surface, and the lower electrode 9 having a surface area approximately twice as large as that of normal polysilicon can be formed.

Then, as shown in FIG. 2D, SiH ₂ C
Using a l ₂ gas and an NH ₃ gas, a silicon nitride film is formed in a thickness of 5 to 10 nm by a normal LPCVD method, and the silicon nitride film is subjected to a heat treatment in an oxidizing atmosphere to form a silicon oxide film on the surface of the silicon nitride film. Then, a capacitive insulating film 10 made of a silicon nitride film, a silicon nitride film, and a silicon oxide film is formed. Subsequently, a polysilicon film is formed to a thickness of 100 to 300 nm by a normal LPCVD method. And
Impurities such as phosphorus are introduced into the polysilicon film by an ion implantation method or a thermal diffusion method, and the polysilicon film is patterned using a normal photolithography technique and a dry etching technique to form the upper electrode 11. As a result, a capacitance portion including the lower electrode, the capacitance insulating film, and the upper electrode is formed.

In the semiconductor device having the capacitor of this configuration, since the titanium nitride film 7 exists at the interface between the lower electrode 9 and the silicon substrate 1, even if the heat treatment is performed after the capacitor is formed, the titanium nitride The film 7 serves as a barrier film to prevent phosphorus in the lower electrode from diffusing into the silicon substrate 1 or a diffusion layer (not shown). For example, as shown in FIG. 3, an electrode 13 is provided on a thick field oxide film 2A, and a diffusion layer 14 is provided on the silicon substrate 1 on both sides of the field oxide film 2A. A parasitic transistor was formed by forming polysilicon 12 doped with phosphorus via a titanium nitride film 7 thereon, and the relationship between the threshold value Vth of the parasitic transistor and the distance D between diffusion layers was examined. For example, after forming a parasitic transistor, 900 ° C., 30 ° C.
When the heat treatment is performed for one minute, as shown in FIG.
Even if it becomes 6 μm or less, a decrease in threshold voltage Vth is not observed. In other words, it can be seen that the separation between the elements is complete even when the distance D is reduced. The conventional example shown in FIG. 4 shows a case where the barrier film does not include the titanium nitride film 7 in the parasitic transistor shown in FIG.
When the thickness is less than μm, the threshold voltage Vth decreases, and the isolation between elements becomes incomplete. By the way, in the case of this embodiment,
There is no possibility that the isolation between elements will be incomplete as in the conventional example,
The phosphorus concentration in the amorphous silicon for the lower electrode is 10 ²⁰ at
om / cm ³ or more.

As shown in FIG. 5 which shows the CV characteristics of the capacitor portion, in the present embodiment, the phosphorus concentration in the amorphous silicon for the lower electrode can be increased to 10 ²⁰ atoms / cm ³ or more. In comparison with the case where the phosphorus concentration is limited to about 7 × 10 ¹⁹ atoms / cm ³ in order to secure the isolation between the elements as described above, the spread of the depletion layer, which is observed by HSG conversion, can be prevented. It is clear that a reduction in the capacitance value can be suppressed. As a result, an increase in capacitance per unit planar area can be achieved using the lower electrode that has been HSG-ized, and it is possible to cope with miniaturization of devices.

Next, a second embodiment of the present invention will be described with reference to FIG. First, as shown in FIG. 6A, a silicon oxide film 2 is formed on a silicon substrate 1, and a contact hole 3 is formed in the silicon oxide film 2 of the interlayer film using a normal photolithography technique and a dry etching technique. I do. Thereafter, as shown in FIG.
Is formed by a CVD method.
For example, using a single-wafer LP-CVD apparatus, tetrakisdimethylaminotitanium (Tetrakis-dim) is used.
thylamino-titanium: TDMAT
(Ti ｛N (CH ₃ ) ₂ ｝ ₄ ) or tetrakis-diethylaminotitanium (Tetrakis-diethyla)
mino-titanium: TDEAT (Ti @ N
(C ₂ H ₅ ) ₂ ｝ ₄ ) and other organic raw materials are thermally decomposed (400
To 500 ° C.) to grow a TiN film. Further, from 500 to 700 using a parallel plate type plasma CVD apparatus from titanium tetrachloride (TiCl ₄ ) and ammonia (NH ₃ ).
A TiN film is grown at ℃. Next, as shown in FIG. 6C, the titanium nitride is etched back using SF ₆ gas to remove the titanium nitride on the interlayer film, leaving the titanium nitride only in the contact, and forming a titanium nitride plug 15. I do. If necessary, the titanium nitride may be densified by performing a heat treatment at 600 to 900 ° C. in a nitrogen or ammonia atmosphere using a lamp anneal or the like.

Then, as shown in FIG. 6D, a phosphorus-doped amorphous silicon film is grown to a thickness of 200 to 500 nm by the LP-CVD method as in the first embodiment.
Patterning is performed into the shape of the lower electrode by using a normal photolithography technique and a dry etching technique. Further, the surface of the amorphous silicon film is made uneven by HSG to increase the surface area of the lower electrode. For example, as the conditions at this time, a temperature of 540 to 650 ° C., a pressure of 10 ⁻³ Torr or less, a flow of Si ₂ H ₆ gas at 20 to 30 sccm for 1 to 2 minutes, and then heating for 1 to 10 minutes may be used. The lower electrode 9 having a surface area approximately twice as large as that of normal polysilicon can be formed. Then, as in the first embodiment, S
Normal LP using iH ₂ Cl ₂ gas and NH ₃ gas
A silicon nitride film is formed to a thickness of 5 to 10 nm by a CVD method. Further, the silicon nitride film is subjected to a heat treatment in an oxidizing atmosphere to form a silicon oxide film on the surface of the silicon nitride film, and a capacitance insulating film 10 including the silicon nitride film, the silicon nitride film, and the silicon oxide film is formed. Next, the normal LPCV
A polysilicon film is formed to a thickness of 100 to 300 nm by Method D.
Then, an impurity such as phosphorus is introduced into the polysilicon film by an ion implantation method or a thermal diffusion method. Then, using a normal photolithography technique and a dry etching technique, patterning is performed in the shape of the upper electrode 11 to form a capacitance portion.

Also in the semiconductor device of the second embodiment, since the titanium nitride plug 15 is present at the interface between the lower electrode 9 and the silicon substrate 1, even if the heat treatment is performed after forming the capacitor, the titanium nitride The plug 15 serves as a barrier film to prevent phosphorus in the lower electrode from diffusing into the silicon substrate 1 or the diffusion layer. As a result, the phosphorus concentration in the amorphous silicon for the lower electrode can be increased to 10 ²⁰ atoms / cm ³ or more. In addition, this makes it possible to prevent the depletion layer from spreading due to the formation of HSG, to suppress an effective decrease in capacitance value, to achieve an increase in capacitance per unit planar area, and to achieve miniaturization of devices. Can respond. Also,
In this embodiment, the titanium nitride plug 15 serving as a barrier film can be formed in the titanium nitride film formation and etching back steps, and therefore, there is also an effect that the number of steps can be reduced as compared with the first embodiment.

Next, a third embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 7A, a thick silicon oxide film 2, a gate oxide film 2B, a gate electrode 16, and a diffusion layer 14 are formed on a silicon substrate 1 to form a transistor and the like. After forming an insulating silicon oxide film 2C on the surface of the gate electrode 16, FIG.
(B) As shown in FIG.
N) A film 17 is formed by a sputtering method or a CVD method, and the titanium nitride film 17 is etched and patterned using a normal photolithography technique and a dry etching technique, and the titanium nitride film 1 is formed only at least in a region covering the diffusion layer.
Leave 7. If necessary, the titanium nitride may be densified by performing a heat treatment at a temperature of 600 to 900 in a nitrogen or ammonia atmosphere using a lamp anneal or the like. Further, instead of the titanium nitride film, a titanium (Ti) film is formed by a sputtering method or a CVD method, and thereafter, a heat treatment is performed at 600 to 900 ° C. in a nitrogen or ammonia atmosphere using a lamp anneal or the like to nitride the titanium nitride film. It may be formed. Thereafter, as shown in FIG. 7C, a silicon oxide film 18 for an interlayer film is formed to a thickness of 300 to 800 nm by a CVD method or the like.

Next, as shown in FIG. 8A, a contact hole 19 is formed in the silicon oxide film of the interlayer film on the diffusion layer by using a usual photolithography technique and a dry etching technique. Then, as shown in FIG. 8B, a phosphorus-doped amorphous silicon film is formed to a thickness of 200 to 500 nm by the LP-CVD method as in the first embodiment.
And is patterned into the shape of the lower electrode by using a normal photolithography technique and a dry etching technique. Subsequently, the surface of the amorphous silicon film is made uneven by HSG to increase the surface area of the lower electrode. For example, at this time, as conditions, a temperature of 540 to 650 ° C. and a pressure of 10 ⁻³ T
At orr or lower, a Si ₂ H ₆ gas may be flowed at 20 to 30 sccm for 1 to 2 minutes, and then heated for 1 to 10 minutes. The lower electrode 9 having a surface area approximately twice as large as that of normal polysilicon can be formed.

Thereafter, as in the first embodiment, SiH ₂
Normal LPCVD using Cl ₂ gas and NH 3 gas
A silicon nitride film is formed to a thickness of 5 to 10 nm by a method. Subsequently, the silicon nitride film is subjected to a heat treatment in an oxidizing atmosphere to form a silicon oxide film on the surface of the silicon nitride film, and a capacitance insulating film 10 including a silicon nitride film, a silicon nitride film, and a silicon oxide film is formed. Next, a polysilicon film is formed to a thickness of 100 to 300 nm by a normal LPCVD method. Then, an impurity such as phosphorus is introduced into the polysilicon film by an ion implantation method or a thermal diffusion method. Then, using a normal photolithography technique and a dry etching technique, patterning is performed in the shape of the upper electrode 11 to form a capacitance portion.

Also in the semiconductor device of the third embodiment, since the titanium nitride film 17 is present at the interface between the lower electrode 9 and the silicon substrate 1, even if heat treatment is performed after forming the capacitance portion, The film 17 serves as a barrier film to prevent phosphorus in the lower electrode from diffusing into the silicon substrate 1 or the diffusion layer. This makes it possible to increase the phosphorus concentration in the amorphous silicon for the lower electrode, to prevent the depletion layer from spreading by HSG, and to suppress a decrease in the effective capacitance value. Capacitance per area can be increased, and it can respond to miniaturization of devices. In the case of the third embodiment, a patterning step of the titanium nitride film 17 is required. However, compared to the first and second embodiments, the titanium nitride coverage is not required, and the sputtering method is not required. There is an advantage that film formation by the method is sufficient, and which method is better may be selected depending on the capacity of the mass production line. The effect of using the titanium nitride film is the same as in the first and second embodiments.

In the first and third embodiments, the phosphorus-doped amorphous silicon film is formed on the titanium nitride barrier film. However, an impurity such as phosphorus is formed on the titanium nitride film. A doped polycrystalline silicon film is formed, the polycrystalline silicon film is left only in the inside of the contact by etching back, and an amorphous silicon film is grown and patterned into the shape of a lower electrode as in the first embodiment. May be.
In the first, second, and third embodiments, the phosphorus-doped amorphous silicon film is used as the lower electrode. However, after the amorphous silicon film not doped with phosphorus or the like is formed, impurities such as phosphorus are ionized. HSG may be formed by injection. In the case of a contact hole having a large aspect ratio, an amorphous silicon film not doped with phosphorus or the like is grown in several steps, and the amorphous silicon film growth and phosphorus ion implantation are repeated to cover the entire lower electrode. Introduce phosphorus. Further, after the amorphous silicon film not doped with phosphorus or the like is converted into an HSG, impurities can be freely introduced by ion implantation.
Further, an arsenic (As) -doped amorphous silicon film may be used instead of the phosphorus-doped amorphous silicon film.

[0024]

As described above, according to the present invention, the barrier film for preventing the transmission of impurities introduced into the lower electrode is provided at the boundary between the diffusion layer of the semiconductor substrate and the lower electrode of the capacitor. Therefore, there is an effect that diffusion of impurities from the lower electrode into the diffusion layer due to the heat treatment can be prevented. As a result, the phosphorus concentration in the amorphous silicon film for the lower electrode can be increased, so that even when a capacitance portion having irregularities is formed, the depletion layer extends on the lower electrode side, and the effective capacitance value decreases. There is an effect that can be prevented. Therefore, the present invention can realize a semiconductor device having a capacitor portion in which the effective capacitance value is not reduced, the transistor characteristics are not degraded, and the electrical insulation between adjacent elements is maintained. Further, according to the manufacturing method of the present invention, it is possible to manufacture a semiconductor device having such a high-capacity and miniaturized capacitance portion.

[Brief description of the drawings]

FIG. 1 is a first sectional view showing a first embodiment of the present invention in the order of manufacturing steps.

FIG. 2 is a second sectional view showing the first embodiment of the present invention in the order of manufacturing steps.

FIG. 3 is a schematic cross-sectional view of a parasitic transistor used to confirm the effect of the present invention.

FIG. 4 is a diagram showing a relationship between a threshold voltage Vth and a distance D.

FIG. 5 is a CV characteristic diagram of the capacitance section according to the first embodiment.

FIG. 6 is a sectional view showing a second embodiment of the present invention in the order of manufacturing steps.

FIG. 7 is a first sectional view showing a third embodiment of the present invention in the order of manufacturing steps.

FIG. 8 is a second sectional view showing the third embodiment of the present invention in the order of manufacturing steps.

FIG. 9 is a cross-sectional view showing an example of a conventional manufacturing method in the order of manufacturing steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Silicon oxide film 3 Contact hole 7 Titanium nitride film 8 Phosphorus-doped amorphous silicon 9 Lower electrode 10 Capacitive insulating film 11 Upper electrode 15 Titanium nitride plug 17 Titanium nitride 18 Silicon oxide 19 Contact hole

Claims (9)

[Claims] A lower electrode formed on an insulating film formed on a surface of the semiconductor substrate and electrically connected to a diffusion layer provided on the semiconductor substrate through a contact hole opened in the insulating film; In a semiconductor device including a capacitor portion formed of a capacitor insulating film formed on a surface of a lower electrode and an upper electrode formed on the capacitor insulating film,
A semiconductor device, wherein irregularities are formed on a surface of the lower electrode, and a barrier film that prevents transmission of impurities exists between the lower electrode and the diffusion layer. 2. The semiconductor device according to claim 1, wherein the irregularities on the surface of the lower electrode are made of HSG silicon grains. 3. The semiconductor device according to claim 1, wherein the barrier film is made of titanium nitride. 4. A step of opening a contact hole reaching a diffusion layer formed in the semiconductor substrate in an interlayer film formed on the semiconductor substrate, and nitriding as a barrier film on at least the diffusion layer in the contact hole. Forming a titanium film, forming a lower electrode on the interlayer film including the contact hole, forming irregularities on the surface of the lower electrode, and forming a capacitance insulating film on the surface of the lower electrode And a step of forming an upper electrode on the capacitive insulating film. 5. The step of forming the titanium nitride film includes the steps of forming titanium, performing a heat treatment in an atmosphere containing nitrogen or ammonia, removing a titanium compound on the interlayer film, 5. The method of manufacturing a semiconductor device according to claim 4, further comprising a step of performing a heat treatment in an atmosphere containing ammonia to nitride the titanium compound on the diffusion layer. 6. The method of manufacturing a semiconductor device according to claim 5, wherein an aqueous solution containing hydrogen peroxide and ammonia is used to remove the titanium compound on the interlayer film. 7. The method of manufacturing a semiconductor device according to claim 5, wherein an aqueous solution containing hydrogen peroxide and sulfuric acid is used to remove the titanium compound on the interlayer film. 8. The semiconductor device according to claim 4, wherein the step of forming the titanium nitride film is a step of performing etching back by dry etching or the like after forming the titanium nitride film and leaving the titanium nitride film only in the contact portion. Manufacturing method. 9. The semiconductor device according to claim 4, wherein the step of forming the titanium nitride film comprises the step of forming titanium and the step of nitriding the titanium film by performing a heat treatment in an atmosphere containing nitrogen or ammonia. Production method.