JP3336402B2 - Thin film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is manufactured smell of semiconductors devices
And a method for forming a TiN film as a barrier film on the surface of a sample , and more particularly , to microwave plasma CVD.
The present invention relates to a method for forming a thin film for forming the TiN film by using a 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 this barrier film is formed of W (tungsten) formed in the contact hole or the via hole. ) Or Al (aluminum) plugs (electrodes) are prevented from reacting with or diffusing into the underlayer. Conventionally, a TiN film has been formed by a reactive sputtering method. However, a TiN film formed by a reactive sputtering method has poor step coverage, and is hardly formed at the bottom of a contact hole. There was a problem that it could not be used. Then microwave plasma C
VD method, among which ECR plasma CV with excellent directivity
Attention has been paid to the D method, and since the ECR plasma CVD method shows a sufficient film-forming property even at the bottom of the hole, it is considered to be promising as a barrier film forming method in the next generation ULSI.

FIG. 12 is a cross-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 disposed around the plasma generation chamber 31 and connected to a DC power supply (not shown), Waveguide 3 for introducing microwaves oscillated from a wave oscillator (not shown) into plasma generation chamber 31
5 and so on. 36 is a microwave introduction window,
Reference numeral 37 denotes a high-frequency source for applying a high frequency (RF) to the microwave introduction window 36, and reference numeral 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 a microwave 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. The reaction chamber 32 and the plasma generation chamber 3
1 is partitioned by a partition plate 41, and a second hole (plasma extraction window) 42 is provided at a substantially central portion of the partition plate 41.
Are formed.

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

The high-frequency generator 37 is composed of a high-frequency generator 46 and a matching box 47, and the microwave introduction window 36 is interposed between the microwave introduction window 36 and the waveguide 35 via a plate electrode 48. Is applied with a high frequency.

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

In order to form a TiN thin film using the above-described apparatus, the inside of the apparatus main body 33 is first reduced to a predetermined pressure by operating an exhaust system, and then TiCl ₄ is supplied from the first introduction pipe 43 to the reaction chamber 32. While supplying Ar, H _2, and N ₂ from the second introduction pipe 45 into the plasma generation chamber 31. Thereafter, the apparatus main body 33 is set to a predetermined pressure.

Further, a voltage is applied to the microwave introduction window 36 by energizing the high frequency generation source 37 to prevent the TiN thin film from adhering to the microwave introduction window 36 due to the sputtering effect of Ar ions by high frequency.

On the other hand, a microwave is introduced from the microwave oscillator into the plasma generation chamber 31 via the waveguide 35, and a DC power supply 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 source gas in the plasma generation chamber 31, and the source gas is decomposed and ionized to generate plasma.

The generated plasma passes through the second hole 42, is accelerated by a diverging magnetic field in the direction of arrow A in the figure, is guided into the reaction chamber 32, and is sampled on the sample stage 38.
A TiN thin film on the surface of the substrate.

After the growth of the TiN film as a barrier film, plugs are buried in contact holes and via holes (hereinafter, referred to as contact holes including via holes) as a next step. W is buried by LPCVD (low pressure CVD),
Is carried out by a reflow method of melting.

[0013]

As described above, the EC
By using the R plasma CVD method, a TiN film can be formed even on the bottom of a fine 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 (sparse) film. If the TiN film is a porous film, after the formation of the TiN film, the next step of forming a W film, and subsequently, the step of etching and removing the W film other than the contact hole by etching back, is performed. If this is done, the porous film formed on the side wall is etched, and a groove is formed along the side wall of the contact hole, so that there is a problem that a sufficient contact cannot be obtained.

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

In addition, incorporating a plug forming step using W or Al after forming a TiN film as a barrier film is necessary.
In addition to increasing the number of processes, the formation of plugs made of W or Al has a problem that the yield is low and the throughput is low, which causes a 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 in a contact hole to be miniaturized. It is possible to form a TiN film as a barrier film capable of achieving a sufficient contact even after the buried formation, and to form a TiN film as a plug capable of achieving a 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 performed.

[0017]

Means for Solving the Problems] method of forming engaging Ru thin film to the first aspect of the present invention in order to achieve the above object, H ₂ and A
mixed gas of r and N _2, or a mixed gas of H ₂ and N ₂ is
Microwave action inside the supplied plasma generation chamber
Generates more plasma, and generates the generated plasma with TiCl
₄ Lead to the reaction chamber to which the gas is supplied, and arrange inside the reaction chamber.
In the method of forming a thin film for forming a TiN film on the surface of a sample, the ratio of the gas flow rate of H _{2 in} the mixed gas supplied to the plasma generation chamber to the gas flow rate of TiCl ₄ supplied to the reaction chamber is set to 2 characterized in that the less, the method of forming the engaging Ru thin film to the second aspect of the present invention, with H ₂
A gas mixture of Ar and N _2, or a mixed gas of H ₂ and N ₂
Of microwaves inside the plasma generation chamber to which air is supplied
To generate plasma, and convert the generated plasma to TiC
l ₄ gas is supplied to the reaction chamber, and the inside of the reaction chamber is
In the method of forming a thin film for forming a TiN film on the surface of a placed sample, the mixed gas supplied to the plasma generation chamber with respect to the gas flow rate of TiCl ₄ supplied to the reaction chamber
The ratio of the N ₂ gas flow rate to 1 or less,
The formation method of the third invention engaging Ru thin film of the present invention, first
Alternatively, in the method for forming a thin film according to the second invention, the TiN film is formed while applying a high frequency to the sample.

[0018]

The following reaction formula can be considered as the mechanism of the reaction of the TiN film. 2TiCl ₄ + N ₂ + 4H ₂ → 2TiN + 8HCl First, consider a case where the supply amount of H ₂ is reduced with respect to the supply amount of TiCl ₄ . In this case, the effect of extracting chlorine from TiCl ₄ is reduced, and it becomes difficult for the reaction formula to proceed from left to right. However, where there is an ion bombardment by plasma, such as at the bottom of the contact hole or a part other than the contact hole, it is considered that TiCl ₄ is decomposed by the energy of the ion bombardment and the formation of the TiN film proceeds. On the other hand, the side wall of the contact hole has little ion bombardment, so that decomposition of TiCl ₄ does not proceed.
Film formation is suppressed. Therefore, the supply amount of H ₂ is set to T
By reducing the supply amount of iCl ₄ , regardless of whether the film is a porous film or not, TiN
The formation of the film is suppressed, and the generation of a groove along the side wall of the contact hole caused by the etching of the porous TiN film, which is a problem at the time of etching back, is prevented. You will get.
In the case where the film formation process is further continued, the film formation gradually progresses upward from the bottom of the contact hole to form a TiN film as a plug with sufficient contact while preventing generation of voids. Can be done.

Next, consider a case where the supply amount of N ₂ is reduced with respect to the supply amount of TiCl ₄ . In this case, TiCl
₄ becomes excessive, so that TiCl ₄ is adsorbed and migrated irrespective of the entire contact hole portion, the bottom and the side wall, and reacts when N ₂ and H ₂ reach the surface portion where TiCl ₄ is migrated. Happens. That is, a reaction having a strong effect of surface migration is obtained, and a conformal film is formed. As a result, a high-quality non-porous TiN film is formed not only on the bottom of the contact hole but also on the side wall, so that the etching does not proceed as fast as the TiN film even during the etch back.
As a result, the formation of a groove along the side wall of the contact hole is prevented, and TiN as a barrier film with sufficient contact is obtained.
A film can be formed. Further, when the film forming process is further performed, the formation of the overhang portion on the side wall portion of the contact hole is suppressed, and the generation of voids is prevented, and the T as a plug with sufficient contact is formed.
The iN film can be formed faster.

Further, according to the third method of forming a thin film according to the present invention, since the TiN film is formed while applying a high frequency to the sample, the directivity of the film-forming substance is enhanced, and the film is formed from the bottom of the contact hole. The film advances, and the first or the second
As the overhang portion is formed by two methods
Also, this overhang portion is reverse sputtered, and TiN
It is possible to prevent the upper portion of the film from being closed, thereby preventing the occurrence of voids. In addition, the formation of a porous TiN film in the vicinity of the side wall portion is suppressed by the ion bombardment effect, and the formation of a groove along the side wall of the contact hole is also prevented during the etch back, so that a barrier film with sufficient contact can be obtained. A TiN film can be formed. Further, by performing a film forming process further continuously, the film is gradually formed upward from the bottom of the contact hole, and a TiN film as a sufficiently contacted plug is formed while preventing generation of voids. that Do and get.

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

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method for forming a thin film according to the present invention will be described below. In this embodiment, a method of forming a thin film according to the present invention, that is, a method of forming a TiN film in a contact hole portion, will be described, including a subsequent film formation of a W film and an etchback of the W film on an insulating film. . Also, W
Without performing film formation, the film formation process is continuously performed, and T
A case where plug embedding with an iN film is performed will also be described.

The configuration of the plasma CVD apparatus used for growing the TiN film of this embodiment is the same as that of the conventional apparatus shown in FIG. 12, and a detailed description thereof will be omitted. In this embodiment, the TiN film is formed by TiCl
_The N ₂ flow rate or the H ₂ flow rate was changed while keeping the flow rate of ₄ at 10 sccm and the Ar flow rate at 43 sccm (however, the pressure was maintained at 1 mTorr), microwave power of 2.8 kw, sample temperature of 460 ° C., and microwave window. The test was performed on a sample having a contact hole having 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 an LPCVD method. Film formation conditions are W
F ₆ flow rate 150 sccm, H ₂ flow rate 750 scc
m, N ₂ flow rate 2700 sccm, pressure 45 mTorr
r, sample temperature was 480 ° C. And then, EC
Each sample was subjected to an etch-back process by the R plasma method. Etch-back of the conditions the flow rate of SF ₆ 100s
ccm, pressure 1mTorr, microwave power 1.5k
w, sample temperature was 100 ° C. In addition, the W film is not formed, and the TiN film is continuously
After embedding the plug with the film, CMP (Chemical
An operation of removing the TiN film above the contact hole by Mechanical Polishing (chemical mechanical polishing) was also performed. And the cross section of the contact hole part of each sample was observed using SEM (scanning electron microscope).

First, the flow rate of TiCl ₄ was set at 10 sccm,
Ar flow rate is 43 sccm, N ₂ flow rate is 15 sccm
And the flow rate of H ₂ is set to 10 sccm and 20 scc.
m, 30 sccm, and 50 sccm were changed to form a TiN film. FIG. 1 is a cross-sectional view of the vicinity of the contact hole under each condition, and FIG.
m, (b) is 20 sccm, (c) is 30 sccm,
(D) shows the case of 50 sccm. FIGS. 2 and 3 show cross sections near the contact hole portion after the subsequent formation of the W film and after the etch back, respectively. FIG.
(A) and FIG. 3 (a) correspond to FIG. 1 (a), and the others are the same. According to this sectional view, when the H ₂ flow rate is 20 sccm or less (the flow rate ratio of H _{2 to} the flow rate of TiCl ₄ is 2 or less), the TiN film 12 becomes the bottom 11 b of the contact hole 11 and the insulating film (SiO ₂ film) 20. Although a film was uniformly formed on the upper portion, the film was hardly formed on the side wall portion 11a (FIGS. 1A and 1B). As a result, even when the etch back was performed, the groove along the side wall 11a of the contact hole was formed. Was not observed (FIGS. 3A and 3B). When the flow rate of H ₂ 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
a (FIGS. 1C and 1D), but the side wall 11
Since the film a was formed thicker at the entrance of the contact hole than at the portion near the bottom, voids 13 were generated at the time of W16 film formation (FIGS. 2C and 2D), and furthermore, the etching was performed. At the time of backing, a groove 14 is formed along the side wall of the contact hole.
And the void 13 becomes a hole 15 (FIG. 3).
(C), (d)).

FIG. 4 is a cross-sectional view schematically showing the vicinity of a contact hole when a TiN film is continuously formed without forming a W film after the process shown in FIG. 1A shows a case where a film forming process is performed subsequently to that shown in FIG. 1A, and FIG.
(C) corresponds to FIG. 1 (c), and (d) corresponds to the case of FIG. 1 (d). As is clear from FIG. 4, in the case of FIGS. 4 (a) and 4 (b) according to the embodiment, since it is difficult to form a film on the side wall portion 11a, no overhang portion is formed and the contact hole 11 is formed. The TiN film 12 was surely buried. However, FIG.
4 (c) and FIG. 4 (d), since the film is sufficiently formed also on the side wall portion 11a, an overhang portion 17 is formed, which is joined to form a void 13 in the TiN film 12. Next, the result of removing the upper part of the TiN film 12 in these samples by CMP is shown in FIG. FIG. 5 (a), FIG.
(B),... Correspond to the cases of FIGS. 4 (a), 4 (b),. As is clear from this, FIG.
5 (a) and FIG. 5 (b), the plug could be reliably formed by the TiN film 12, but in the comparative examples of FIG. 5 (c) and FIG.
Was only partially buried, and the formation of the plug was incomplete.

Next, the flow rate of TiCl _4, each flow rate of Ar is 10 sccm, under the same conditions as in Example of 43sccm the previous, 10 sccm flow rate of N ₂ (flow ratio of N ₂ to the flow rate of TiCl ₄ is 1) To a constant
₂ TiN films were formed when the flow rates were 20 sccm and 30 sccm. A cross section near each contact hole is shown in FIG.
(B) shows the case of 30 sccm. 7 and 8 show cross sections near the contact hole portion after the subsequent formation of the W film and after the etch back. FIGS. 7A and 8
(A) corresponds to FIG. 6 (a), and the same applies to other parts. The result was obtained by adjusting the flow rate of N ₂ to 15 in the previous embodiment.
sccm and the flow rate of H ₂ was 20 sccm and 30 sccm.
1 (b), (c), FIG. 2 (b),
(C) and comparison with FIGS. 3 (b) and (c). Then
A conformal film is formed on the side wall portion 11a (FIGS. 6 (a) and 6 (b); however, FIG. 6 (b) shows a slightly lower conformality), and even after the etch back. The TiN film 12 remains on the side wall without being etched (FIGS. 8A and 8B), and it can be seen that the TiN film 12 having good film quality is also formed on the side wall 11a.
Further, since the film is conformal, no void is generated even when the film W16 is formed (FIGS. 7A and 7B). However, since the film was formed by ECR plasma having good directivity even though it was conformal, the film thickness of the side wall was 20% or less as compared with the bottom of the contact hole.

FIG. 9 is a cross-sectional view schematically showing the vicinity of the contact hole portion when the TiN film is continuously formed without forming the W film after the process shown in FIG. 6 (a) and 6 (b) show the case where the film forming process is performed subsequently to those shown in FIGS. 6 (a) and 6 (b), and FIG. Corresponding, however, shows a case where a sample having fine contact holes 11 having a diameter of about 0.5 μm is continuously subjected to a TiN film forming process. As is clear from FIG. 9, FIG.
9A and 9B, the film can be formed conformally, and the formation of an overhang portion on the side wall 11a of the contact hole 11 can be suppressed. Of course the side wall 1
A film could be formed from the side of 1a. Therefore, a TiN which is sufficiently contacted while preventing generation of voids
The film 12 can be embedded in the contact hole 11 more quickly. Also, in the case of (c) according to the embodiment in which the film is formed in the fine contact hole 11, the TiN film 12 which can be formed conformally from the side wall portion 11 a and has no void is embedded in the contact hole 11. Was completed. Next, the TiN in these samples was
FIG. 10 shows the result of removing the upper portion of the film 12 by CMP. As is clear from this, FIG.
(A), FIG. 10 (b), FIG. 10 (c), TiN
The plug was successfully formed by the film 12. In the case of FIG. 9C according to the embodiment, the conformal degree is high and no groove is formed in the TiN film 12, so that not only the CMP but also the etch back process is performed as shown in FIG. 10C. A good plug could be formed.

Next, a case where a high frequency is applied to the sample will be described. The film formation condition is TiCl ₄ flow rate 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, microwave window RF power 1
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) after 2 minutes of film formation, (b) after 2 minutes of film formation (total of 4 minutes) than (a), and (c) after 1 minute of film formation (total of 5 minutes) after (b) (D) shows CM
The plug after P processing is shown. Even under conditions where an overhang portion and a porous film are formed unless high frequency is applied, the application of high frequency to the sample can prevent the overhang portion from being formed due to the reverse sputtering effect, and can prevent the overhang portion from being formed near the bottom portion 11b. The follow-up can be improved. Further, the formation of a porous TiN film in the vicinity of the side wall 11a can be prevented by the ion bombardment effect, and thus the TiN film 12 as a barrier film with sufficient contact can be formed (a). If film formation is further continued, contact hole 11
Can be embedded with the TiN film 12 ((b),
(C)) By removing the upper part of the TiN film 12 by using the CMP process, the plug of the TiN film 12 could be surely formed.

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

The application of such a high frequency is shown in FIG.
(B) or FIG. 6 (a), the the combined use in the method of forming a thin film according to the embodiment shown in (b), it is possible to shorten the processing time.

As described above, in the present invention,
The flow rate of TiCl ₄ supplied to the reaction chamber 32 is
H ₂ or N in the mixed gas supplied to the plasma generation chamber 31
The ratio of the gas flow rates of the _two is optimized, and
Sample 39 result of applying a high frequency (silicon 21), co <br/> contact hole sidewall portions good TiN film 1 also film quality to 11a
2 can be formed in a conformal manner, or the barrier can be formed without the deterioration of the contact due to the formation of the groove 14 even in the subsequent formation of the W film 16 and the etch back process by the reverse sputtering action and the ion bombardment action. The TiN film 12 as a film could be formed. Further, in each case, the generation of the voids 13 could be prevented as a result. Further, without forming the W film 16, the TiN
By continuing the film formation, the TiN film 12 as a plug could be formed .

[0032]

Of the present invention As apparent from the above description, according to the invention
According to the method for forming a thin film according to the first invention , plasma generation
Mixed gas of H ₂ and N ₂ supplied to the chamber , or
Plasma mixed gas with Ar by microwave
Introduced into the reaction chamber and supplied to the reaction chamber.
Upon ₄ is reacted with the gas to form a TiN film, TiC
l ₄ of the ratio of gas flow rates of H ₂ to a gas flow rate <br/> 2 or less treasure, the formation of TiN film on the side wall of the hole portion is suppressed
Therefore, the formation of a porous TiN film can be prevented , and no groove is formed from the side wall of the hole even in the formation of the W film and the etch back in the next step, so that a device having excellent contact characteristics can be obtained. Can be made. Also W
Embedded a TiN film without the formation of such film in the contact hole, plug can be formed, reducing the number of higher engineering,
The throughput and the yield can be improved.

Further , according to the method for forming a thin film according to the second invention,
Then, mixing of H ₂ and N ₂ supplied to the plasma generation chamber
Gas or a mixture of these gases with Ar
Into a reaction chamber and introduce it into the reaction chamber.
Upon reacted with TiCl ₄ gas supplied to form a TiN film, treasure and the ratio of gas flow rate of N ₂ to the gas flow rate of TiCl ₄ and 1 or less, a good TiN films also quality Oite the side wall of the hole portion is formed Therefore, even when the W film is formed and etched in the next step, no groove is generated from the hole side wall, and as a result, a device having excellent contact characteristics can be manufactured. The embedded TiN film without the film formation, such as W film in the contact hole, the plug can be formed, reducing the number of higher engineering, it is possible to improve the throughput and yield.

Further , according to the thin film forming method of the third invention,
Lever, in the method of the first or second invention, since a TiN film while applying a high frequency to the sample, even when the deposition and etching of the W film in the next process, the generation of the groove from the side wall of the hole portion As a result, a device having excellent contact characteristics can be produced. The embedded TiN film without the film formation, such as W film in the contact hole, the plug can be formed, reducing the number of higher engineering, it is possible to improve the throughput and yield.

[Brief description of the drawings]

1 (a) to 1 (d) show an ECR plasma CVD apparatus in which the flow rate ratio of H _{2 to} TiCl ₄ is changed,
FIG. 4 is a schematic cross-sectional view showing a shape near a contact hole when an iN film is grown.

FIGS. 2A to 2D are schematic diagrams showing shapes near a contact hole portion when a W film is grown by an LPCVD method after the steps shown in FIGS. 1A to 1D. It is sectional drawing.

FIGS. 3A to 3D are schematic diagrams showing shapes near a contact hole portion when a W film on an insulating film is etched back after the process shown in FIGS. 2A to 2D; FIG.

FIGS. 4A to 4D show the vicinity of a contact hole portion when a TiN film is continuously grown without growing a W film after the process shown in FIGS. 1A to 1D. FIG. 3 is a schematic cross-sectional view showing a shape.

FIGS. 5A to 5D show shapes near the contact hole when the TiN film on the insulating film is removed by CMP after the process shown in FIGS. 4A to 4D; It is a typical sectional view.

FIGS. 6 (a) and (b) show an ECR plasma CVD apparatus in which the flow rate ratio of N _{2 to} TiCl ₄ is 1,
FIG. 9 is a schematic cross-sectional view showing a shape near a contact hole when an N film is grown.

FIGS. 7A and 7B are schematic diagrams showing the shapes near the contact hole when a W film is grown by the LPCVD method after the process shown in FIGS. 6A and 6B; It is sectional drawing.

FIGS. 8A and 8B are schematic diagrams showing the shape near the contact hole when the W film on the insulating film is etched back after the process shown in FIGS. 7A and 7B; FIG.

9 (a) and 9 (b) show 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). FIG. 6 (a) is a schematic cross-sectional view showing the shape near the contact hole when a TiN film is continuously grown without growing a W film on a sample having a contact hole diameter of 0.5 μm. It is.

FIGS. 10A and 10B show the case where the TiN film on the insulating film is removed by CMP after the process shown in FIGS. 9A and 9B, and FIG. FIG. 4 is a schematic cross-sectional view showing the shape near the contact hole when the TiN film on the insulating film is removed by CMP after the process shown in FIG.

11A and 11B are cross-sectional views schematically showing a relationship between a TiN film formation processing time and a film formation state and plugs after film formation.
Shows the case after 2 minutes of film formation, (b) shows the case after 2 minutes of film formation further than (a) (total 4 minutes), and (c) shows the case after 1 minute of film formation further than (b) (total 5 minutes). , (D) shows the plug after the CMP process.

FIG. 12 is a schematic sectional view showing a generally used plasma CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Contact hole 11a Side wall part 11b Bottom part 12 TiN film 20 Insulating film 21 Silicon

Claims (3)

(57) [Claims] 1. A mixed gas of H ₂ , Ar and N ₂ , or H 2
Inside the plasma generation chamber to which a mixed gas of ₂ and N ₂ is supplied
Plasma is generated by the action of microwaves in the
Plasma into the reaction chamber where the TiCl ₄ gas is supplied.
A thin film forming method for forming a TiN film on a surface of a sample disposed inside the reaction chamber;
To the plasma generation chamber for the TiCl ₄ gas flow rate
A method for forming a thin film, wherein a ratio of a gas flow rate of H ₂ in a supplied mixed gas is 2 or less. _2. A mixed gas of H ₂ , Ar and N ₂ , or H 2
Inside the plasma generation chamber to which a mixed gas of ₂ and N ₂ is supplied
Plasma is generated by the action of microwaves in the
Plasma into the reaction chamber where the TiCl ₄ gas is supplied.
A thin film forming method for forming a TiN film on a surface of a sample disposed inside the reaction chamber;
To the plasma generation chamber for the TiCl ₄ gas flow rate
The thin film forming method which is characterized in that the ratio of gas flow rate of N ₂ in the mixed gas supplied to one or less. 3. A TiN while applying a high frequency to said sample
3. The method according to claim 1 , wherein a film is formed.
Method of forming the thin film.