JP4319269B2 - Thin film formation method by plasma CVD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin film forming method and a plasma CVD apparatus for forming a thin film for wiring using vapor phase growth (CVD) by plasma in a process of manufacturing a semiconductor device.
[0002]
[Prior art]
In the recent field of semiconductor device manufacturing, the integration and miniaturization of elements are increasingly advanced. Miniaturization of elements requires new technology in the manufacturing process. Here, a description will be given of contact formation for improving the electrical contact between the wiring material and the underlying Si (silicon) at the bottom of the contact hole and obtaining an ohmic contact.
[0003]
In conventional contact formation, a titanium film that is a barrier film between a wiring material and underlying Si is formed by sputtering, and then a solid phase reaction between titanium at the bottom of the contact hole and underlying Si is caused by annealing to form titanium silicide. It was done by that. Good contact with low contact resistance was formed by sufficiently forming this titanium silicide. However, in the conventional contact formation using the sputtering method, it is difficult to form Ti having a sufficient thickness at the bottom of a high aspect ratio fine hole.
[0004]
Therefore, in recent years, contact formation by a CVD method with good step coverage is proposed. According to the contact formation by the CVD method, a titanium film or a titanium silicide film is formed. Conventionally, two examples of the contact forming technique by the CVD method are known. The first example is a technique for forming a titanium silicide layer by reacting TiCl ₄ and underlying Si directly at the bottom of a contact hole using a titanium halide gas such as TiCl ₄ (titanium tetrachloride) as a raw material ( For example, C.Arena, J.Faguet, RFFoster, JTHillman, F.Martin and Y.Morand: Advanced Metallization for ULSI Applications in 1994, eds.R Blumenthal and G.Janssen (MRS, Pittsburgh, PA, 1995) p.259) . A second example is a technique in which a titanium silicide film is deposited on the entire inside of a contact hole using a titanium halide gas (for example, TiCl ₄ ) and a silane-based gas (Si _n H _{2n + 2} ) as raw materials (for example, S. Mizuno, M. Tagami, S. Hasegawa and Y. Numasawa: Jpn. J. Appl. Phys. Vol. 36 (1997) p. 5651). The first example and the second example in the contact formation technique by the plasma CVD method will be described below in detail with reference to the drawings.
[0005]
FIG. 5 shows the first example and schematically shows a process of forming a titanium film and a titanium silicide film in a fine contact hole on a silicon substrate by plasma CVD. In the lower graph of FIG. 5, the horizontal axis indicates the elapsed time of the substrate processing and the corresponding steps (processing steps), and the vertical axis indicates the flow rate of TiCl ₄ that is important in the film forming method. The flow control of TiCl ₄ is shown. The upper contact hole shows the film formation state in each step. In FIG. 5, reference numeral 71 denotes a base Si substrate, 72 denotes an insulating film (SiO ₂ ), and 73 denotes a contact hole. In the film formation, a first step 74 in which plasma is generated by H ₂ (hydrogen) immediately above the substrate heated and heated, and TiCl ₄ is introduced into the plasma to form a titanium silicide film 76 at the bottom of the contact hole 73. Then, a second step 75 is performed to form a titanium film 77 on the side wall portion of the contact hole and the upper flat portion.
[0006]
TiCl ₄ or a precursor formed by decomposition of TiCl ₄ by the above plasma (TiCl _x : hereinafter referred to as “TiCl _x ”) is formed on the surface of the contact hole sidewall portion and the upper flat portion made of silicon oxide (SiO ₂ ). As a result of being reduced by hydrogen radicals generated in the plasma, a titanium film is formed. However, since Si is exposed at the bottom of the contact hole, TiCl ₄ or TiCl _x reacts with Si, and a certain thickness portion of the underlying Si at the bottom of the contact hole is replaced with the titanium silicide layer 76. The speed of this reaction is limited by the diffusion of Si from the underlying Si 71 in the titanium silicide layer 76 or the diffusion of TiCl _x generated in the plasma and adsorbed on the surface. It is controlled by the partial pressure of TiCl ₄ and time. Further, in this method, the deposition rate of the titanium film 77 formed on the contact hole side wall portion and the upper flat portion is much slower than the formation rate of the titanium silicide layer 76 formed on the bottom of the contact hole. The ratio of the thickness of the contact hole bottom to the thickness of the upper flat portion, that is, the bottom film coverage is very good. The titanium silicide layer 76 functions as a diffusion barrier between the wiring material formed in the hole in a later step and the underlying Si, and has a function of improving electrical contact.
[0007]
FIG. 6 shows the second example and schematically shows the formation of a titanium silicide film in a fine contact hole on the Si substrate by the plasma CVD method. In Figure 6, the lower graph shows, taking the elapsed time and steps corresponding to those of the substrate processing in the horizontal axis, the vertical axis is the flow rate of TiCl ₄ and SiH ₄ flow rate of TiCl ₄ and SiH ₄ at each step Indicates control. The upper contact hole is a diagram showing the state of film formation in each step, as in FIG. In the film formation, a first step 81 in which plasma is generated by H ₂ immediately above the substrate heated and heated, and TiCl ₄ and SiH ₄ are introduced into the plasma to form a titanium silicide film on the entire inner and outer surfaces of the contact hole 73. The second step 82 for forming 83 is performed. In the second example, since the titanium silicide film 83 is formed using a titanium halide gas (for example, TiCl ₄ ) and a silane-based gas (Si _n H _{2n + 2} ) as raw materials, TiCl _x or This has the advantage that the reaction between the chlorine radical and the underlying Si is greatly suppressed.
[0008]
[Problems to be solved by the invention]
In the first example of contact formation using the plasma CVD method, TiCl ₄ is formed on the surface of the underlying Si by plasma before the titanium silicide layer 76 is formed on the surface of the underlying Si 71 exposed at the bottom of the contact hole at the beginning of the reaction. When chlorine radicals generated by decomposition of silicon arrive, it reacts violently with the underlying Si, Si is vaporized as silicon tetrachloride (SiCl ₄ ), etc., and the underlying Si layer is rapidly etched into pits. . In FIG. 5, reference numeral 77 denotes an etched portion. This etching is abrupt at the very beginning of the reaction and is difficult to control. As a result, there arises a problem that the reliability and yield of the device are lowered, such as destruction of the diffusion layer near the bottom of the contact hole and generation of electrical failure (mainly leakage current).
[0009]
In the second example of contact formation using the plasma CVD method, there is a problem that sufficient step coverage cannot be obtained because of the high reactivity of the silane-based gas.
[0010]
An object of the present invention is to solve the above-described problem. In forming a titanium film and a titanium silicide film by plasma CVD using TiCl ₄ as a raw material, the step coverage is good and erosion of the underlying Si layer is suppressed. Another object of the present invention is to provide a thin film forming method and a plasma CVD apparatus for manufacturing a highly reliable element.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a thin film formation method by plasma CVD according to the present invention is configured as follows .
In the thin film formation method by plasma CVD according to the present invention (corresponding to claim 1 ), titanium tetrachloride, hydrogen, and a silane-based gas are introduced into a container in which a substrate is placed to generate plasma, and titanium silicide is formed on the substrate. A thin film forming process for forming a titanium silicide film is a method for forming a film. The first process is to generate hydrogen by introducing hydrogen into a container, and a silane-based gas and titanium tetrachloride are predetermined in the hydrogen plasma. This is a second step in which a flow rate is increased at a constant rate per unit time and introduced to form a titanium silicide film at least at the bottom of the contact hole on the substrate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0013]
A first embodiment of a thin film forming method using plasma CVD according to the present invention will be described with reference to FIGS. FIG. 1 schematically shows a method for forming a thin film in a contact hole. In the lower graph of FIG. 1, the horizontal axis indicates the elapsed time of the substrate processing and the corresponding steps (processing steps), and the vertical axis indicates the flow rates of TiCl ₄ and SiH ₄ that are important in the film forming method of the present invention. The flow control of TiCl ₄ and SiH ₄ at each step is shown. The upper contact hole is a diagram showing the film formation state at the end of each step. FIG. 2 shows the configuration of a plasma CVD apparatus for carrying out this thin film forming method.
[0014]
First, the configuration of the plasma CVD apparatus will be described with reference to FIG. The container 11 forming the processing chamber is formed of a conductive member and is held at a ground potential. An exhaust port 12 is formed in the side wall of the container 11, and an exhaust mechanism 14 is connected to the exhaust port 12 via an exhaust pipe 13. The inside of the container 11 is maintained in a required reduced pressure state by the exhaust mechanism 14. Inside the container 11, an upper electrode 16 is provided on the ceiling via an insulator 15, and a substrate holder 18 is provided on the bottom via an insulator 17. The substrate holder 18 is provided as a lower electrode, and is provided in parallel to the lower surface of the upper electrode 16. The upper electrode 16 has a function as a gas supply unit, and is connected to a reaction gas supply mechanism 19 and a gas introduction unit 20 is formed on the lower surface. The reactive gas supply mechanism 19 includes an H ₂ supply source 19a and a mass flow controller 19b for adjusting the supply amount thereof, a TiCl ₄ supply source 19c and a mass flow controller 19c for adjusting the supply amount thereof, a silane-based gas supply source 19e, and an supply thereof. It is comprised from the mass flow controller 19f which adjusts quantity. According to the reaction gas supply mechanism 19, as described in the thin film formation method according to each embodiment below, the supply amount of each gas is controlled by each of the mass flow controllers 19b, 19d, and 19f, so that H ₂ (hydrogen ), TiCl ₄ (titanium tetrachloride), and a silane-based gas can be selectively supplied to the gas introduction unit 20 according to the process. The upper electrode 16 is connected with a high-frequency power supply mechanism 23 including a high-frequency power source 21 and a matching circuit 22 to supply power necessary for processing. Inside the substrate holder 18, a heater 24 for heating the substrate holder 18 is incorporated, and a thermocouple 25 for detecting the temperature state is further provided. A substrate 26 to be processed is mounted on the upper surface of the substrate holder 18. The illustration of the mechanism for transporting the substrate 26 and the port for loading / unloading the substrate 26 is omitted.
[0015]
In the plasma CVD apparatus, the inside of the container 11 is maintained in a reduced pressure state by the exhaust mechanism 14 through the exhaust port 12, and the substrate 26 is placed on the substrate holder 18 in the container 11. The substrate holder 18 is heated to a predetermined temperature by the heater 24 and the thermocouple 25, and the temperature of the substrate 26 is maintained at a constant temperature in the range of 400 ° C to 650 ° C. The substrate 26 is a silicon substrate. In FIG. 1, reference numeral 31 denotes a base Si, which corresponds to the substrate 26. As shown in FIG. 1, an insulating film (SiO ₂ ; silicon oxide) 32 is formed on the base Si 31, and a contact hole 33 is formed in the insulating film 32. A titanium film 34 and a titanium silicide film 35 are formed in the contact hole 33. The formation of the titanium film 34 and the titanium silicide film 35 is constituted by two steps. That is, in the film formation, a first step 41 in which plasma is generated by H ₂ immediately above the substrate heated and heated, and TiCl ₄ is introduced into the plasma to form a titanium silicide film 35 at the bottom of the contact hole 33. Further, this is performed by the second step 42 in which the titanium film 34 is formed on the side wall portion of the contact hole and the upper flat portion.
[0016]
In the first step 41, H ₂ is supplied from the reaction gas supply mechanism 19 at a flow rate in the range of 100 to 1000 sccm, H ₂ is introduced into the container 11 from the gas introduction unit 20, and the interior of the container 11 is 0.01 to After maintaining a constant pressure within the range of 1 Torr, high frequency power is applied from the high frequency power supply mechanism 23 to the upper electrode 16 to generate plasma immediately above the substrate 26 in the container 11. The applied power in this embodiment is 200 to 1000 W, and the frequency of the applied power is 13.56 to 200 MHz.
[0017]
Next, in a second step 42, TiCl ₄ is introduced to form a titanium silicide film 35 at the bottom of the contact hole 33. Temperature of the substrate 26, the pressure in the container 11, for the flow rate of H ₂ and the high-frequency power are the same as the conditions of the first step 41. TiCl ₄ is introduced at a constant rate per unit time from a flow rate of 0 sccm to a predetermined flow rate (preferably 3.5 sccm), and then flows at a constant flow rate to form a titanium silicide film 35. The flow rate of TiCl ₄ in this embodiment is 1 to 5 sccm, and is increased from 0 sccm to a predetermined flow rate over a period of 5 to 15 seconds. In FIG. 1, the slope 43 at the leading edge of the flow rate characteristic shown in the second step 42 indicates the state of the flow rate control of TiCl ₄ . By controlling the flow rate of TiCl ₄ , the amount of chlorine radicals in the initial reaction is reduced, and the titanium silicide film 35 is formed in a state where etching of the underlying Si 31 is suppressed. Once the titanium silicide film 35 is formed, the titanium silicide film 35 has high chemical resistance to chlorine radicals and serves as a protective film for the base Si31, so that etching of the base Si31 by chlorine radicals is suppressed. Therefore, thereafter, a constant flow rate of TiCl ₄ is introduced (state 44). The growth rate of the titanium silicide film 35 when the introduced amount of TiCl ₄ is constant is determined by the rate at which TiCl _x generated in the Si or plasma from the underlying Si 31 and adsorbed on the surface diffuses in the titanium silicide. Therefore, it is possible to control the amount by which the base Si31 is replaced with the titanium silicide film 35 with time. Further, since the deposition rate of the titanium film 34 formed on the side wall of the contact hole is much lower than the growth rate of the titanium silicide film 35, the film coverage at the bottom is improved.
[0018]
According to the thin film forming method according to the first embodiment, the etching of the base Si 31 is suppressed, and the titanium film 34 and the titanium silicide film 35 having a good film coverage at the bottom of the contact hole are formed.
[0019]
Next, a second embodiment of the thin film forming method according to the present invention will be described with reference to FIG. 3 and FIG. The apparatus configuration in which the thin film forming method according to the second embodiment is carried out is substantially the same as the configuration shown in FIG. The difference is that a silane-based gas (Si _n H _{2n + 2} ), eg, SiH _4, is introduced in addition to TiCl ₄ from the reaction gas supply mechanism 19 and the gas introduction part 20 of the upper electrode 16. The thin film formation method according to the second embodiment is illustrated in FIG. The content shown in FIG. 3 is also similar to the content described in FIG. 1, and the same elements in FIG. That is, in FIG. 3, 31 is a base Si, 32 is an insulating film, 33 is a contact hole, 35 is a titanium silicide film, and 34 is a titanium film. The difference is that in the lower graph, the first step 51, the second step 52, and the third step 53 are indicated by the elapsed time on the horizontal axis, and “TiCl ₄ or SiH ₄ ” is indicated by the flow rate on the vertical axis. It is that you are. The formation of the titanium film and the titanium silicide film according to the second embodiment is performed by the first to third steps 51 to 53.
[0020]
The first step 51 is the same as the first step 41 of the first embodiment. That is, in the first step 51, the temperature of the substrate 26 on the substrate holder 18 is maintained at a constant temperature in the range of 400 to 650 ° C., 100 to 1000 sccm of H ₂ is introduced from the gas introduction unit 20, and the inside of the container 11 is reduced to 0. While maintaining a constant pressure of 01 to 1 Torr, high-frequency power is supplied / applied from the high-frequency power supply mechanism 23 to the upper electrode 16 to generate plasma on the substrate 26 in the container 11. The applied power is 200 to 1000 W, and the frequency is 13.56 to 200 MHz.
[0021]
In the second step 52, SiH ₄ and TiCl ₄ are introduced, and a titanium silicide film 35 is deposited inside the contact hole 33 and the entire upper flat portion. SiH ₄ and TiCl ₄ are introduced at a constant rate per unit time from a flow rate of 0 sccm to a predetermined flow rate (preferably SiH ₄ = 1.0 sccm, TiCl ₄ = 3.5 sccm). The conditions in this embodiment are that the flow rate of TiCl ₄ is 1 to 5 sccm, the flow rate of SiH ₄ is 0.2 to 1.5 sccm, and the time of 5 to 15 seconds from 0 sccm to a predetermined flow rate is set for each gas. Increase the flow rate. The flow rate ratio between TiCl ₄ and SiH ₄ is always kept constant (preferably (TiCl ₄ / SiH ₄ ) = 3.5). The temperature of the substrate 26, the temperature in the container 11, the H ₂ flow rate, and the high frequency power are the same as those in the first step 51.
[0022]
Here, the effect of the second step 52 is that the titanium silicide film 35 is formed as a result of the reaction between the highly active silane radicals generated in the plasma and TiCl _x similarly generated in the plasma. Etching of the underlying Si 31 by radicals is almost eliminated. In this case, similarly to the first embodiment, the flow rate control in the introduction of TiCl ₄ further reduces the generation amount of chlorine radicals, and further, silane radicals react with chlorine radicals in the plasma or on the surface. As the chlorine radicals are consumed and reduced, the etching of the underlying Si 31 by the chlorine radicals is further suppressed. Further, since the titanium silicide film 35 is formed by the reaction between the silane radical and TiCl _x at the initial stage of the reaction, the substitution reaction between TiCl _x and the base Si 31 is also suppressed, and the titanium silicide film 35 is deposited on the surface of the base Si 31. Again the introduction of SiH ₄ is performed the same flow control as TiCl _4, the flow rate ratio of TiCl ₄ and SiH ₄ are coercive always constant. In FIG. 3, slopes 54 and 55 of the flow rate characteristic of the second step 52 indicate the state of flow control of TiCl ₄ and the state of flow control of SiH ₄ , respectively.
[0023]
Next, in the third step 53, the introduction of SiH ₄ is stopped, and TiCl ₄ continues to flow in the second step 54 at a constant flow rate to deposit the titanium film 34 and the titanium silicide film 35. The condition in this embodiment is that the TiCl ₄ flow rate is 1 to 5 sccm. The temperature of the substrate 26, the temperature in the container 11 and the high frequency power are the same as in the first step. In the third step 53, by the titanium silicide film 35 medium formed in the second step 52, TiCl _x adsorbed on Si or generated surface in the plasma from the underlying Si31 to diffuse and move further titanium silicide film 35 grows. As in the first embodiment, it is possible to control the amount by which the underlying Si 31 is replaced with the titanium silicide film 35 with time. On the other hand, the titanium silicide film 35 is formed in the second step 52 also on the side surface and the upper flat portion of the contact hole 33. In the third step 53, the titanium film 34 is deposited on the titanium silicide film. This is because there is no supply of Si atoms as in the case where the base is a silicon oxide film. Since the deposition rate of the titanium film 34 is much slower than the growth rate of the titanium silicide film 35 at the bottom of the contact hole, the film coverage at the bottom of the contact hole is good as in the first embodiment.
[0024]
Therefore, according to the thin film forming method of the second embodiment, etching of the underlying Si is greatly suppressed, and a titanium film and a titanium silicide film having a good film coverage at the bottom of the contact hole are formed.
[0025]
Next, a third embodiment of the thin film forming method according to the present invention will be described with reference to FIG. 4 and FIG. The apparatus configuration in which the thin film forming method according to the third embodiment is carried out is substantially the same as the configuration shown in FIG. Also in this embodiment, TiCl ₄ and SiH ₄ are introduced from the reaction gas supply mechanism 19 and the gas introduction part 20 of the upper electrode 16. The thin film formation method according to the third embodiment is illustrated in FIG. The content shown in FIG. 4 is similar to the content described in FIG. 1, and the same reference numerals are given to the same elements in FIG. That is, in FIG. 4, 31 is a base Si, 32 is an insulating film, 33 is a contact hole, 35 is a titanium silicide film, and 34 is a titanium film. As shown in the lower graph, the elapsed time on the horizontal axis indicates the first step 61, the second step 62, and the third step 63, and the flow rate on the vertical axis indicates “TiCl ₄ or SiH ₄ ”. The formation of the titanium film and the titanium silicide film according to the third embodiment is performed by the first to third steps 61 to 63.
[0026]
The contents of the first step 61 in the thin film forming method according to the third embodiment are exactly the same as the first steps 41 and 51 described above.
[0027]
In the next second step 62, only the SiH ₄ gas is supplied from the reaction gas supply mechanism 26 and introduced into the container 11 through the gas introduction unit 20 at a constant flow rate for a fixed time. The introduction flow rate of SiH ₄ according to this embodiment is 5 to 100 sccm, and the introduction time is 5 to 20 seconds. The temperature of the substrate 26, the temperature in the container 11, the H ₂ flow rate, and the high frequency power are the same as those in the first step 61. In the second step 62, the introduced SiH ₄ is decomposed in the plasma, whereby a silicon atom (Si) layer or a silicon hydride (SiH _x ) adsorption layer 64 is formed on the substrate surface.
[0028]
In the next third step 63, only the TiCl ₄ gas is supplied from the reaction gas supply mechanism 19 and introduced into the container 11 through the gas introduction unit 20 at a constant flow rate for a fixed time. In introducing TiCl ₄ , as in the first and second embodiments described above, the flow rate is increased at a constant rate per unit time from a flow rate of 0 sccm to a predetermined flow rate. That is, the flow rate of TiCl ₄ in this embodiment is 1 to 5 sccm, and is increased from 0 sccm to a predetermined flow rate over a period of 5 to 15 seconds. In this third step, TiCl _x generated in the plasma at the beginning of the reaction reacts with the silicon atomic layer or silicon hydride adsorption layer 64 formed in the second step 62 to form the titanium silicide film 35. In the formation of the titanium silicide film 35, the amount of chlorine radicals generated is reduced by the flow rate control in the introduction of TiCl ₄ as in the above embodiments, and the etching of the underlying Si 31 is suppressed. Thereafter, under the constant flow rate of TiCl ₄ , the growth of the titanium silicide film 35 continuously occurs by the diffusion movement of Si or TiCl _x in the titanium silicide film 31 as in the above embodiments. As in each of the above embodiments, the amount by which the underlying Si 31 is replaced with the titanium silicide film 35 can be controlled with time. Further, TiCl _x generated in the plasma also reacts with the silicon atomic layer or silicon hydride adsorption layer 64 formed in the second step 62 to form the titanium silicide film 35 on the side surface and upper flat portion of the contact hole 33. However, after the silicon atomic layer or silicon hydride is consumed, the titanium film 34 is formed. Here, since the silicon atomic layer or the silicon hydride adsorption layer 64 formed in the second step 62 has good step coverage, the titanium silicide film 35 formed in the third step 63 is the second embodiment. The step coverage is better than that of the titanium silicide film formed by the reaction of SiH ₄ and TiCl ₄ formed in (1). Furthermore, since the deposition rate of the titanium film formed on the upper flat portion is much slower than the growth rate of the titanium silicide film at the bottom of the contact hole, the film coverage at the bottom is still good.
[0029]
Therefore, according to the thin film formation method of the third embodiment, etching of the underlying Si by chlorine radicals is suppressed, and a titanium film and a titanium silicide film are formed that have good step coverage at the side wall and film coverage at the bottom in the contact hole. Is done.
[0030]
In the above embodiment, an example in which the thin film forming method according to the present invention is applied to a parallel plate type plasma CVD apparatus has been described. However, the present invention may be applied to other types of plasma CVD apparatuses such as an ECR type plasma CVD apparatus and an inductively coupled type. It is also possible to use a plasma CVD apparatus or the like.
[0031]
【The invention's effect】
As is apparent from the above description, according to the present invention, in the thin film forming method for forming a thin film for wiring on the surface of a substrate using plasma CVD, the initial introduction amount or introduction of the reactive gas introduced into the plasma. Since the etching method is controlled by a predetermined method, etching of the underlying Si is suppressed, and a titanium film and a titanium silicide film having excellent step coverage and excellent film coverage on the bottom of the contact hole can be formed. .
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a first embodiment of a thin film forming method according to the present invention.
FIG. 2 is a longitudinal sectional view showing an internal structure of a plasma CVD apparatus in which a thin film forming method according to the present invention is implemented.
FIG. 3 is an explanatory view showing a second embodiment of the thin film forming method according to the present invention.
FIG. 4 is an explanatory view showing a third embodiment of a thin film forming method according to the present invention.
FIG. 5 is a diagram illustrating a first example of a conventional thin film forming method.
FIG. 6 is a diagram illustrating a second example of a conventional thin film forming method.
[Explanation of symbols]
11 Container 16 Upper electrode 18 Substrate holder 20 Gas introduction part 26 Substrate 31 Base Si (silicon)
32 Insulating film (SiO ₂ )
33 Contact hole 34 Titanium film 35 Titanium silicide film 64 Si adsorption layer

Claims (1)

In a thin film formation method by plasma CVD in which titanium tetrachloride, hydrogen, and a silane-based gas are introduced into a container in which a substrate is arranged to generate plasma, and a titanium silicide film is formed on the substrate.
The thin film forming step for forming the titanium silicide film includes a first step of introducing plasma into the vessel to generate plasma, and a constant amount of silane-based gas and titanium tetrachloride in the plasma by hydrogen up to a predetermined flow rate per unit time. And a second step of forming a titanium silicide film at least at the bottom of the contact hole on the substrate by introducing at an increased rate.

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