JPH06140348A - Method for forming thin film - Google Patents

Abstract

PURPOSE:To obtain a sufficient film growth to the bottom of a contact hole by setting the ratio of the gas flow rate of H2 to the gas flow rate of TiCl4 to a value equal to or smaller than a specific value when a TiN film is formed using TiCl4, H2, Ar and N2 as raw material gases. CONSTITUTION:When a TiN film is formed, the ratio of the gas flow rates of TiCl4 and H2 is set to two or smaller, and the flow rates of TiCl4, Ar and N2 are made constant, namely, 10sccm, 43sccm and 15sccm, respectively, with the flow rate of H2 being varied to 10sccm, 20sccm, 30sccm and 50sccm. In the sectional views of the vicinity of the contact hole under the respective conditions, (a), (b), (c) and (d) indicate the instances of 10sccm, 20sccm, 30sccm and 50sccm, respectively. According to the sectional views, for the H2 flow rate of 20sccm, a TiN film 12 was uniformly grown on the bottom 11b of a contact hole 11 and an insulating film 20, but little grown on a side wall 11a, whereby no groove is seen along the contact hole side wall 11a even after an etchback.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thin film mainly for manufacturing a semiconductor device, and more particularly to a method for forming a thin film using a plasma CVD method, particularly an ECR plasma CVD method.

[0002]

2. Description of the Related Art A TiN film as a barrier film is formed in a contact hole or a via hole in a semiconductor device, and the barrier film is a W (tungsten) formed in the contact hole or the via hole. ) Or Al (aluminum) plug (electrode) is prevented from reacting with the underlayer or diffusing into the underlayer. Conventionally, the TiN film was formed by using the reactive sputtering method. However, the TiN film formed by the reactive sputtering method has poor step coverage and is hardly formed on the bottom of the contact hole. There was a problem that it could not be used. So microwave plasma C
VD method, among which ECR plasma CV with excellent directivity
The D method has attracted attention, and since the ECR plasma CVD method exhibits a sufficient film-forming property even on the bottom of the hole, it is regarded as a promising method for forming a barrier film in the next-generation ULSI.

FIG. 12 is a sectional view schematically showing a plasma CVD apparatus generally used for forming a thin film. The plasma CVD apparatus includes an apparatus main body 33 including a plasma generation chamber 31 and a reaction chamber 32, an excitation coil 34 arranged around the plasma generation chamber 31 and connected to a DC power source (not shown), and a micro Waveguide 3 for introducing microwaves oscillated from a wave oscillator (not shown) into the plasma generation chamber 31
It is composed of 5 mag. 36 is a microwave introduction window,
Reference numeral 37 denotes a high-frequency generation source that applies a high frequency (RF) to the microwave introduction window 36, and 38 denotes a sample table on which a sample 39 is placed.

The plasma generation chamber 31 is formed in a substantially cylindrical shape, and a first hole 40 for introducing microwaves is formed in a substantially central portion of an upper wall of the plasma generation chamber 31. A reaction chamber 32 having a larger diameter than the plasma generation chamber 31 is integrally formed below the plasma generation chamber 31. In addition, the reaction chamber 32 and the plasma generation chamber 3
1 is partitioned by a partition plate 41, and a second hole (plasma lead-out window) 42 is formed in the partition plate 41 at a substantially central portion thereof.
Are formed.

Further, a first introduction pipe 43 is connected to the side wall of the reaction chamber 32, and an exhaust pipe 44 communicating with an exhaust system (not shown) is connected to the bottom of the reaction chamber 32. A second introduction pipe 45 is connected to the upper wall of the plasma generation chamber 31.

The high frequency generator 37 comprises a high frequency generator 46 and a matching box 47, and a microwave introducing window 36 is interposed via a plate electrode 48 sandwiched between the microwave introducing window 36 and the waveguide 35. A high frequency is applied to.

A high frequency oscillator 51 for applying a high frequency to the sample 39 is provided on the sample table 38, and a matching box 50 is provided.
Connected through. By applying a predetermined high frequency to the sample 39 from the high-frequency oscillator 51 to form a thin film, the bias voltage applied to the sample 39 acts and the step coverage is excellent even when the uneven surface of the sample 39 is minute. A thin film can be formed.

In order to form a TiN thin film using the above apparatus, first, the exhaust system is operated to reduce the pressure inside the apparatus main body 33 to a predetermined pressure, and then TiCl ₄ is introduced from the first introducing pipe 43 into the reaction chamber 32. Meanwhile, Ar, H ₂ and N ₂ are supplied into the plasma generation chamber 31 from the second introducing pipe 45. After that, the device body 33 is set to a predetermined pressure.

Further, the high-frequency generator 37 is energized to apply a voltage to the microwave introduction window 36 to prevent the TiN thin film from adhering to the microwave introduction window 36 due to the Ar ion sputtering effect by the high frequency.

On the other hand, microwaves are introduced from the microwave oscillator into the plasma generation chamber 31 via the waveguide 35, and a DC power source is connected to the exciting coil 34 to generate a magnetic field in the plasma generation chamber 31. Then, high-energy electrons collide with the raw material gas in the plasma generation chamber 31, and the raw material gas is decomposed and ionized to generate plasma.

The generated plasma passes through the second hole 42, is accelerated in the direction of arrow A in the figure by the divergent magnetic field, is guided into the reaction chamber 32, and is placed on the sample table 38.
A TiN thin film is formed on the surface of.

Further, after the TiN film as a barrier film is grown, a plug is formed in a contact hole or a via hole (hereinafter, referred to as a contact hole including the via hole) as a next step. W is embedded by LPCVD (Low Pressure CVD) method or Al
Is carried out by the reflow method of melting.

[0013]

As described above, the EC
If the R plasma CVD method is used, the TiN film can be formed even on the fine bottom portion of the contact hole. However, the ECR plasma CVD method has high directivity, and the TiN film formed on the side wall of the contact hole tends to be a porous film. When the TiN film is a porous film, after the formation of the TiN film, a W film forming step, which is the next step, and a step of etching away the W film other than the contact hole portion by etching back are performed. When this is done, this porous film formed on the side wall portion is etched, a groove is formed along the side wall portion of the contact hole, and there is a problem that a sufficient contact cannot be made.

Further, an overhang (protruding state) portion is easily formed on the TiN film formed on the side wall of the contact hole, and if the film formation is further continued, the overhang portions are connected to each other and the upper portion is closed. As a result, there is a problem that voids (cavities) remain in the TiN film and the device characteristics are deteriorated. Therefore, there is a problem that it is difficult to form the plug with the TiN film due to the generation of the void and the formation of the porous TiN film.

Incorporating a plug forming process using W or Al after forming a TiN film as a barrier film is
As the number of steps is increased, the formation of plugs using W or Al has a low yield and a low throughput, which causes a problem of cost increase in a mass production line.

The present invention has been made in view of the above problems, and relates to the formation of a TiN film on a miniaturized contact hole, as well as a sufficient formation on the bottom of the contact hole and the subsequent formation of a plug on the contact hole. It is possible to form a TiN film as a barrier film capable of achieving sufficient contact even after the buried formation, and to form a TiN film as a plug capable of achieving sufficient contact without generation of voids. It is an object of the present invention to provide a method for forming a thin film that can be formed.

[0017]

In order to achieve the above object, a first thin film forming method according to the present invention is a plasma CV method.
By using the D method, TiCl ₄ , H ₂ , Ar, and N ₂ or TiCl ₄ , H _2, and N ₂ are used as source gases, and T
In a method of forming a thin film for forming an iN film, TiCl ₄
The ratio of the gas flow rate of H _{2 to} the gas flow rate of H ₂ is set to 2 or less, and the second thin film forming method according to the present invention uses plasma CVD to form TiCl ₄ and H ₂
And Ar and N ₂ or TiCl ₄ , H ₂ and N ₂ as raw material gases in the method of forming a TiN film, the ratio of the gas flow rate of N _{2 to} the gas flow rate of TiCl ₄ is 1 A third method for forming a thin film according to the present invention is characterized in that the following is used, and TiCl ₄ , H ₂ , Ar and N ₂ or Ti
In the method of forming a TiN film using Cl ₄ , H ₂ and N ₂ as source gases, a TiN film is formed while applying a high frequency to a sample.

[0018]

The following reaction formula is considered as the mechanism of the reaction of the TiN film. 2TiCl ₄ + N ₂ + 4H ₂ → 2TiN + 8HCl Then, first, consider the case where the supply amount of H ₂ is made lower than the supply amount of TiCl ₄ . In this case, the effect of extracting chlorine from TiCl ₄ is lowered, and the reaction formula becomes difficult to proceed from left to right. However, it is considered that TiCl ₄ is decomposed by the energy of the ion bombardment at the place where the ion bombardment is caused by plasma, such as the bottom of the contact hole or the part other than the contact hole, and the TiN film is formed. On the other hand, since the side wall of the contact hole is less ion-impacted, the decomposition of TiCl ₄ does not proceed, resulting in TiN
The film formation is suppressed. Therefore, the supply amount of H ₂ is T
By lowering the supply amount of iCl ₄ , the TiN on the side wall can be formed regardless of whether it is a porous film or not.
The formation of a film is suppressed, the formation of a groove along the side wall of the contact hole caused by the etching of the porous TiN film, which is a problem during etch back, is prevented, and a TiN film as a barrier film with sufficient contact is formed. You will get it.
Further, when the film formation process is further continued, the film formation gradually progresses upward from the bottom of the contact hole, and a TiN film as a plug with sufficient contact is formed while preventing the occurrence of voids. It will be possible.

Next, consider the case where the supply amount of N ₂ is made lower than the supply amount of TiCl ₄ . In this case, TiCl
_{Since 4} is excessive, TiCl ₄ is adsorbed and migrated irrespective of the entire contact hole part, bottom part and side wall part, and reacts when N ₂ and H ₂ reach the surface part where TiCl ₄ is migrating. Will happen. That is, a reaction having a strong effect of surface migration is formed and a conformal film formation is performed. As a result, a good quality non-porous TiN film is formed not only on the bottom of the contact hole but also on the side wall of the contact hole, and the etching does not proceed rapidly only at the TiN film.
As a result, it is possible to prevent the formation of grooves along the side wall of the contact hole, and to make TiN as a barrier film with sufficient contact.
A film can be formed. Further, when the film formation process is further continued, formation of an overhang portion on the side wall portion of the contact hole is suppressed, a void is prevented from being formed, and a T as a plug with sufficient contact is formed.
The iN film can be formed faster.

Further, according to the third method for forming a thin film of the present invention, since the TiN film is formed while applying a high frequency to the sample, the directivity of the film-forming material is enhanced and the TiN film is formed from the bottom of the contact hole. Even if the film is advanced and the overhang portion is not formed on the side wall portion of the contact hole by the first or second method, the overhang portion is reverse-sputtered and the upper portion of the TiN film is closed. Therefore, the occurrence of voids can be prevented. Further, the ion bombardment action suppresses the formation of a porous TiN film in the vicinity of the side wall portion, prevents the formation of a groove along the side wall of the contact hole even during etchback, and provides a barrier film with sufficient contact. Ti
The N film can be formed. Further, by further performing the film formation process, the film formation gradually progresses upward from the bottom of the contact hole, and a TiN film as a plug with sufficient contact is formed while preventing the occurrence of voids. You will get it. Further, when the method for forming the first or second thin film and the method for forming the third thin film described above are combined, the film forming rate can be further increased.

The addition of Ar gas is used for the purpose of increasing the plasma intensity and increasing the film formation rate.

[0022]

EXAMPLE An example of a method of forming a thin film according to the present invention will be described below. In this example, a method for forming a thin film according to the present invention, that is, a film formation of a TiN film on a contact hole portion will be described including a subsequent film formation of a W film and an etchback of a W film on an insulating film. . Also, W
The film is not formed, and the film forming process is continuously performed as it is.
A case in which the plug is embedded with the iN film will also be described.

The structure of the plasma CVD apparatus used for the growth of the TiN film of this embodiment is the same as that of the conventional one shown in FIG. 12, and a detailed description thereof will be omitted here. In addition, the TiN film in the present embodiment is formed of TiCl
The flow rate of ₄ was 10 sccm, the flow rate of Ar was 43 sccm, and the N ₂ flow rate or H ₂ flow rate was changed (however, the pressure was maintained at 1 mTorr). Microwave power 2.8 kw, sample temperature 460 ° C., microwave window The test was performed on a sample having a contact hole with a diameter of about 1 μm under the condition of RF power of 150 w. Next, a W film was formed on each sample by the LPCVD method. Film forming condition is W
F ₆ flow rate 150 sccm, H ₂ flow rate 750 sccc
m, N ₂ flow rate 2700 sccm, pressure 45 mTorr
r, the sample temperature was 480 ° C. And then, EC
Each sample was etched back by the R plasma method. Etchback conditions are SF ₆ flow rate 100 s
ccm, pressure 1mTorr, microwave power 1.5k
w, the sample temperature was 100 ° C. In addition, the W film is not formed, and the TiN film forming process is continuously performed as it is.
After plugging with a film, CMP (Chemical
Mechanical polishing (Chemical Polishing) was also performed to remove the TiN film above the contact hole. Then, the cross section of the contact hole portion of each sample was observed using an SEM (scanning electron microscope).

First, the flow rate of TiCl ₄ is 10 sccm,
Ar flow rate 43sccm, N ₂ flow rate 15sccm
Is kept constant at a flow rate of H ₂ of 10 sccm and 20 sccc.
The TiN film was formed by changing m, 30 sccm, and 50 sccm. FIG. 1 shows a cross-sectional view in the vicinity of the contact hole portion under each condition, where (a) is 10 scc.
m, (b) is 20 sccm, (c) is 30 sccm,
(D) shows the case of 50 sccm. 2 and 3 are sectional views of the vicinity of the contact hole portion after the W film is formed and after the etch back. Figure 2
(A) and FIG. 3 (a) correspond to FIG. 1 (a), and the others are the same. According to this cross-sectional view, when the H ₂ flow rate is 20 sccm or less (the H ₂ flow rate ratio to the TiCl ₄ flow rate is 2 or less), the TiN film 12 includes the bottom portion 11 b of the contact hole 11 and the insulating film (SiO ₂ film) 20. A film was uniformly formed on the upper portion, but almost no film was formed on the side wall portion 11a (FIGS. 1A and 1B). As a result, even if etching back is performed, the groove along the contact hole side wall 11a is formed. Was not observed (FIGS. 3 (a) and 3 (b)). Further, when the H ₂ flow rate is 30 sccm or more (the flow rate ratio of H _{2 to} the flow rate of TiCl ₄ is 3 or more), the TiN film 12 forms the sidewall portion 11
A film was also formed on a (FIGS. 1C and 1D), but the side wall 11
Since the film of a is formed thicker at the entrance of the contact hole than at the part near the bottom, voids 13 are generated during the film formation of W16 (FIGS. 2C and 2D), and further etching is performed. When backing, groove 14 along the side wall of the contact hole
Occurred, and the void 13 became a hole 15 (Fig. 3
(C), (d)).

Further, FIG. 4 is a cross-sectional view schematically showing the vicinity of the contact hole portion when the Ti film is continuously formed without forming the W film after the step shown in FIG. It is a figure, (a) shows the case where a film-forming process is performed following the thing of FIG. 1 (a), (b) shows FIG. 1 (b),
1C corresponds to FIG. 1C, and FIG. 1D corresponds to FIG. 1D. As is clear from FIG. 4, in the case of FIG. 4A and FIG. 4B according to the embodiment, it is difficult to form a film on the side wall portion 11a, so that the overhang portion is not formed and the inside of the contact hole 11 is not formed. The TiN film 12 could be buried reliably. However, in FIG.
In the case of (c) and FIG. 4 (d), the overhang portion 17 was formed because the film was sufficiently formed on the side wall portion 11a, and the void 13 was formed in the TiN film 12 by joining the overhang portion 17. Next, FIG. 5 shows the result of removing the upper portion of the TiN film 12 in these samples by CMP. 5 (a) and FIG.
(B), ... Corresponds to the case of FIG. 4 (a), FIG. 4 (b) ,. As is clear from this, FIG.
In the case of (a) and FIG. 5 (b), the plug could be reliably formed by the TiN film 12, but in the case of FIG. 5 (c) and FIG. 5 (d) in the comparative example, the contact hole 11 was formed.
Was only partially filled, and the formation of the plug was incomplete.

Next, the TiCl ₄ flow rate and the Ar flow rate were 10 sccm and 43 sccm, respectively, under the same conditions as in the previous embodiment, and the N ₂ flow rate was 10 sccm (the N ₂ flow rate ratio to the TiCl ₄ flow rate was 1). To a constant value, H
_{2 A} TiN film was formed when the flow rate was 20 sccm and 30 sccm. FIG. 6 shows a cross section in the vicinity of each contact hole portion, (a) is 20 sccm,
(B) shows the case of 30 sccm. 7 and 8 show cross sections near the contact hole portion after the W film is formed and after the etch back. 7 (a) and 8
(A) corresponds to FIG. 6 (a), and the others are the same. The result is obtained by setting the flow rate of N ₂ in the above embodiment to 15
The flow rate of H ₂ is 20 sccm and 30 sccm.
1 (b), (c), FIG. 2 (b),
Compare with (c), FIG. 3 (b), and (c). Then,
A conformal film formation is also performed on the side wall portion 11a (FIGS. 6A and 6B, but the conformality is slightly lower in FIG. 6B), and even after the etch back. The TiN film 12 is not etched and remains on the side wall (FIGS. 8A and 8B), which shows that the TiN film 12 having a better film quality is also formed on the side wall 11a.
Further, since the film is conformal, no void is generated even when W16 is formed (FIGS. 7A and 7B). However, since the film was formed by ECR plasma having good directivity even though it is conformal, the film thickness on the side wall portion was 20% or less compared to the bottom portion of the contact hole.

Further, FIG. 9 is a cross-sectional view schematically showing the vicinity of the contact hole portion when the Ti film is continuously formed without forming the W film after the step shown in FIG. 6A and 6B show a case where a film forming process is performed subsequent to that of FIGS. 6A and 6B, and FIG. 6C shows a case of FIG. 6A. Corresponding, however, shows the case where a TiN film forming process is continuously applied to a sample having a fine contact hole 11 having a diameter of about 0.5 μm. As is clear from FIG. 9, FIG.
In the case of (a) and FIG. 9 (b), it is possible to form a film conformally, it is possible to suppress the formation of an overhang portion in the side wall portion 11a of the contact hole 11, and the bottom portion 11b side of the contact hole 11 is formed. Originally side wall 1
It was possible to form a film also from the 1a side. Therefore, TiN is sufficiently contacted while preventing the generation of voids.
The film 12 can be embedded in the contact hole 11 faster. Also, in the case of (c) according to the example in which the film is formed in the fine contact hole 11, the film can be formed conformally from the side wall portion 11a, and the TiN film 12 having no void is embedded in the contact hole 11. I was able to. Then the TiN in these samples
The result of removing the upper portion of the film 12 by CMP is shown in FIG. As is clear from this, FIG.
In the case of (a), FIG. 10 (b) and FIG. 10 (c), TiN
The film 12 allowed the plug to be reliably formed. In the case of FIG. 9C according to the example, since the conformality is high and no groove is formed in the TiN film 12, not only CMP but also etchback treatment is performed as shown in FIG. 10C. It was possible to form a simple plug.

Next, the case where a high frequency is applied to the sample will be described. The film forming conditions are a TiCl ₄ flow rate of 10 scc
m, N ₂ flow rate 15 sccm, H ₂ flow rate 50 sccc
m, Ar flow rate 43 sccm, microwave power 2.8
kw, sample temperature 460 ° C, RF power of microwave window 1
It was 50 w, and a high frequency of 13.56 MHz (500 w) was applied to the sample using the high frequency oscillator 51 (FIG. 12). FIG. 11 is a cross-sectional view schematically showing the relationship between the TiN film formation processing time and the film formation state and the plug after film formation,
(A) is after 2 minutes of film formation, (b) is after 2 minutes of film formation (a total of 4 minutes) than (a), and (c) is after 1 minute of film formation (a total of 5 minutes) than (b). Shows the case, (d) CM
The plug after P processing is shown. Even under the condition that the overhang portion and the porous film are formed unless the high frequency is applied, the formation of the overhang portion can be prevented by the reverse sputtering effect by applying the high frequency to the sample, and in the vicinity of the bottom portion 11b. You can improve your surroundings. In addition, the impact of the ions can prevent the formation of the porous TiN film in the vicinity of the side wall portion 11a, and thus the TiN film 12 as a barrier film with sufficient contact can be formed (a). When the film formation is further continued, the contact hole 11
The TiN film 12 can be embedded in ((b),
(C)) By removing the upper portion of the TiN film 12 using the CMP process, the plug of the TiN film 12 could be reliably formed.

In this embodiment, the sample is 13.56 MH.
A high frequency of z was applied, but in another embodiment, 2 MHz, 4
By applying a high frequency of 00 kHz, the same effect as in the case of the embodiment can be obtained.

Further, in this embodiment, the high frequency was applied to the sample under the condition that the overhang portion and the porous film were formed unless the high frequency was applied, but in another embodiment, as shown in FIG.
A high frequency may be applied in combination with the thin film forming method according to the embodiment shown in (a), (b) or FIGS. 6 (a), (b), in which case the treatment time should be shortened. You can

[0031] As described above, with the flow rate of TiCl _4, the flow rate of Ar constant by changing the flow ratio of H ₂ or N ₂ to the flow rate of TiCl _4, or the result of applying a high frequency, of TiCl ₄ The flow rate ratio of H _{2 to} the flow rate is 2 or less, the formation of the TiN film 12 on the contact hole side wall 11a is suppressed, or the flow rate ratio of N _{2 to} the flow rate of TiCl ₄ is 1 or less. As a result, the contact hole sidewall 1
The TiN film 12 having a good film quality can be conformally formed on the layer 1a, or the groove 14 is generated by the subsequent film formation of the W film 16 and the etchback process due to the reverse sputtering action and the ion bombardment action. It was possible to form the TiN film 12 as a barrier film without deterioration of contact due to the above. Further, in any case, as a result, the generation of the void 13 could be prevented. Further, the TiN film 12 as a plug could be formed by continuing the TiN film formation without forming the W film 16.
Further, the present invention can be applied not only to the contact hole but also to the formation of the TiN film on all the hole-shaped portions.

[0032]

As is apparent from the above description, according to the thin film forming method of the present invention, TiCl ₄ , H ₂ , Ar and N ₂ or TiCl ₄ is formed by using the plasma CVD method.
In the method of forming a TiN film using Cl ₄ , H ₂ and N ₂ as source gases, the ratio of the gas flow rate of H _{2 to} the gas flow rate of TiCl ₄ is set to 2 or less, and the TiN film on the side wall of the hole is formed. Since the formation of the film is suppressed, a porous TiN film is not formed on the side wall of the hole, and a groove is not generated from the side wall of the hole even when the W film is formed and etched back in the next step. As a result, a device having excellent contact characteristics can be manufactured. Further, the TiN film can be buried in the contact hole to form the plug without forming the W film or the like, so that the number of steps can be reduced and the throughput and the yield can be improved.

According to the above method, TiCl ₄ , H ₂ , Ar and N ₂ or TiCl ₄ , H ₂ and N ₂ are used as the source gas for Ti using the plasma CVD method.
In the method of forming a thin film for forming an N film, the ratio of the gas flow rate of N _{2 to} the gas flow rate of TiCl ₄ is set to 1 or less, and a TiN film of good film quality is formed even on the side wall of the hole. No groove is formed from the side wall of the hole during film formation and etching, and as a result, a device having excellent contact characteristics can be produced. Further, the TiN film can be buried in the contact hole to form the plug without forming the W film or the like, so that the number of steps can be reduced and the throughput and the yield can be improved.

According to the above method, TiCl ₄ , H ₂ , Ar, and N ₂ or TiCl ₄ , H _2, and N ₂ are used as the source gas for Ti using the plasma CVD method.
In the thin film forming method for forming the N film, since the TiN film is formed while applying a high frequency to the sample, no groove is generated from the side wall of the hole even when the W film is formed and etched in the next step. As a result, a device with excellent contact characteristics can be created. Further, the TiN film can be buried in the contact hole to form the plug without forming the W film or the like, so that the number of steps can be reduced and the throughput and the yield can be improved.

[Brief description of drawings]

1 (a) to 1 (d) use an ECR plasma CVD apparatus and change the flow rate ratio of H _{2 to} TiCl ₄ to obtain T
FIG. 6 is a schematic cross-sectional view showing a shape in the vicinity of a contact hole portion when an iN film is grown.

2 (a) to (d) are schematic views showing the shape in the vicinity of a contact hole portion when a W film is grown by an LPCVD method after the steps shown in FIGS. 1 (a) to (d). FIG.

3 (a) to 3 (d) are schematic views showing the shape in the vicinity of a contact hole portion when the W film on the insulating film is etched back after the steps shown in FIGS. 2 (a) to 2 (d). FIG.

4 (a) to (d) are views showing the vicinity of a contact hole portion when a TiN film is continuously grown without growing a W film after the steps shown in FIGS. 1 (a) to (d). It is a schematic sectional view showing a shape.

5A to 5D show shapes in the vicinity of a contact hole portion when the TiN film on the insulating film is removed by CMP after the steps shown in FIGS. 4A to 4D. It is a schematic sectional view.

6 (a) and 6 (b) are an ECR plasma CVD apparatus in which the flow rate ratio of N _{2 to} TiCl ₄ is 1, and Ti
FIG. 6 is a schematic cross-sectional view showing a shape in the vicinity of a contact hole portion when an N film is grown.

7 (a) and 7 (b) are schematic views showing the shape in the vicinity of a contact hole portion when a W film is grown by LPCVD after the steps shown in FIGS. 6 (a) and 6 (b). FIG.

FIGS. 8A and 8B are schematic views showing the shape in the vicinity of a contact hole portion when the W film on the insulating film is etched back after the steps shown in FIGS. 7A and 7B. FIG.

9 (a) and 9 (b) are diagrams showing a case where a TiN film is continuously grown without growing a W film after the steps shown in FIGS. 6 (a) and 6 (b). 6 (a), but a schematic cross-sectional view showing the shape in the vicinity of the contact hole portion when a TiN film is continuously grown without growing a W film on a sample having a contact hole diameter of 0.5 μm Is.

FIGS. 10A and 10B show a case where the TiN film on the insulating film is removed by CMP after the steps shown in FIGS. 9A and 9B, and FIG. FIG. 6 is a schematic cross-sectional view showing a shape in the vicinity of a contact hole portion when the TiN film on the insulating film is removed by CMP after the step shown in FIG.

FIG. 11 is a cross-sectional view schematically showing the relationship between the TiN film formation processing time and the film formation state and the plug after film formation,
Shows the case after 2 minutes of film formation, (b) shows the case after 2 minutes of film formation (a total of 4 minutes) from (a), and (c) shows the case after 1 minute of film formation (a total of 5 minutes) from (b). , (D) show the plugs after the CMP process.

FIG. 12 is a schematic cross-sectional view showing a commonly used plasma CVD apparatus.

[Explanation of symbols]

 11 Contact Hole 11a Side Wall 11b Bottom 12 TiN Film 20 Insulating Film 21 Silicon

Claims (3)

[Claims] 1. TiCl _{4 is formed} by using a plasma CVD method.
And H ₂ , Ar and N ₂ or TiCl ₄ , H ₂ and N ₂ as raw material gases in the method of forming a thin film, the gas flow rate of H ₂ relative to the gas flow rate of TiCl ₄ is changed. A method of forming a thin film, characterized in that the ratio is 2 or less. 2. TiCl _{4 is formed} by using a plasma CVD method.
In the thin film forming method of forming a TiN film using TiCl ₄ , H ₂ , Ar and N ₂ or TiCl ₄ , H ₂ and N ₂ as source gases, the gas flow rate of N ₂ with respect to the gas flow rate of TiCl ₄ is A method of forming a thin film, wherein the ratio is 1 or less. 3. TiCl _{4 is formed} by using a plasma CVD method.
In the method of forming a TiN film using TiCl ₄ , H ₂ , Ar and N ₂ or TiCl ₄ , H ₂ and N ₂ as source gases, a TiN film is formed while applying a high frequency to a sample. A method for forming a thin film, comprising: