KR20140038328A - Metal film forming method - Google Patents

Abstract

Provided is a metal film formation method capable of forming a high-throughput metal film with less impurities by chemical vapor deposition (CVD). The first process of the method includes arranging a processed substrate in a treatment basin; supplying deposition materials consisting of metal-containing compounds having a ligand with a nitrogen-carbon bond in the molecular structure and a structure that nitrogen in the ligand is coordinated on a metal, and a reductive gas consisting of at least one kind selected from ammonia, hydrazine, and derivatives thereof, to the processed substrate to form an initial metal film by CVD. The second process includes supplying the hydrogen gas to the treatment basin to conduct hydrogen treatment to the processed substrate. The third process includes supplying deposition materials consisting of metal-containing compounds identical to the first process and a reductive gas consisting of the hydrogen gas to the initial metal film formed on the processed substrate to form a main metal film by CVD. [Reference numerals] (AA) Nickel amidinate; (BB) Purge; (CC) Step 1 - Initial film formation; (DD) Step 2 - Hydrogen treatment; (EE) Step 3 - Major film formation; (FF) Step 4 - Purge

Description

Metal film formation method {METAL FILM FORMING METHOD}

TECHNICAL FIELD This invention relates to the metal film-forming method which forms a metal film by chemical vapor deposition (CVD).

In recent years, semiconductor devices have been required to achieve high speeds and low power consumption. For example, in order to realize lower resistance of contact portions or gate electrodes of sources and drains of MOS semiconductors, silicides are employed by salicide processes. To form. As such silicides, attention has been paid to nickel silicides (NiSi) which consume less silicon and are capable of lowering resistance.

In the formation of the NiSi film, a method of forming a nickel (Ni) film on a Si substrate or a polysilicon film by physical vapor deposition (PVD) method such as sputtering and then annealing and reacting in an inert gas is widely used (for example, , Patent Document 1).

In addition, attempts have been made to use the Ni film itself as a capacitor electrode of a DRAM.

However, with the miniaturization of semiconductor devices, sufficient step coverage is not obtained with PVD. For this reason, the method of forming a nickel film into a film by chemical vapor deposition (CVD) method with a good step coverage is examined, and patent document 2 uses nickel amidate as a film-forming raw material (precursor), and uses ammonia () as a reducing gas. It is disclosed to form a nickel film by CVD using NH ₃ ).

By the way, when forming a Ni film by using these, since N is contained in a process gas, N flows into a film and Ni nitride (Ni _x N) is formed simultaneously at the time of Ni film formation, and the film obtained is an impurity. It becomes Ni film | membrane containing N, and the film | membrane resistance becomes high.

In order to improve this point, Patent Document 3 discloses removing N in a film by forming a Ni film containing N using nickel amidate and NH ₃ and then modifying the film in a hydrogen atmosphere. .

Japanese Patent Laid-Open No. 9-153616 Japanese Patent Laid-Open No. 2011-066060 International Publication No. 2011/040385

However, since the processing time becomes longer by adding the post process after film formation in this manner, throughput decreases. Moreover, in the said patent document 3, in order to improve the purity of Ni film | membrane, it is necessary to repeat film-forming and a modification process multiple times, and processing time becomes longer. This problem is not limited to the case of forming Ni by using an amidate-based raw material, and a metal-containing compound having a ligand having a nitrogen-carbon bond in its molecular structure and having a structure in which nitrogen in the ligand is coordinated to the metal. In the case of forming a metal film by use of the same, the same exists.

This invention is made | formed in view of such a situation, Comprising: It aims at providing the metal film film formation method which can form a metal film with few impurities by CVD at high throughput.

In order to solve the above problems, the present applicant firstly has a ligand having a nitrogen-carbon bond in a molecular structure represented by nickel amidate, and a nickel-containing compound having a structure in which nitrogen in the ligand is coordinated with nickel, and ammonia Film formation of an initial nickel film by CVD using at least one reducing gas selected from hydrazine and derivatives thereof, and then a nickel film forming a main nickel film by CVD using a hydrogen gas as the reducing gas. The method was proposed (Japanese Patent Application No. 2011-191917). As a result, the main nickel film can be formed in a state in which impurities such as nickel nitride (Ni-N) or nickel carbide (Ni-C) are low, and the nitrogen in the initial nickel film can be formed by hydrogen gas used in the main nickel film. Can be removed.

However, according to the subsequent examination results, the impurities of Ni-N or Ni-C introduced during the initial nickel film formation may not be sufficiently removed by hydrogen at the time of forming the main nickel film. It has been found that the specific resistance of the Ni film is deteriorated and that the cause of the nickel silicide formation defect is caused. The present invention also solves this new problem.

That is, the present invention provides a metal-containing compound in which a substrate to be processed is disposed in a processing container, and on the substrate to be treated, a ligand having a nitrogen-carbon bond in its molecular structure and a structure in which nitrogen in the ligand is coordinated to the metal. Supplying a film forming raw material, and a reducing gas comprising at least one selected from ammonia, hydrazine, and derivatives thereof, and forming a initial metal film by CVD; and then supplying hydrogen gas into the processing container. A second step of performing hydrogen treatment on the substrate to be processed, and a metal having a structure having a nitrogen-carbon bond in the molecular structure on the initial metal film formed on the substrate, and a structure in which nitrogen in the ligand is bound to the metal; The film-forming raw material composed of the containing compound and the reducing gas composed of hydrogen gas are supplied, and are mainly subjected to CVD. Providing a metal film formation method which is characterized by having a third step for film formation in the film.

In the present invention, a metal amidate-based compound can be used as the metal-containing compound.

Nickel amidate can be used as the metal amidate compound, and a nickel film can be formed as the metal film. In this case, the second step may be performed at 160 to 500 ° C., the pressure at the time of performing the second step may be 333.3 to 13330 Pa, and the flow rate of hydrogen gas at the time of performing the second step is 25 to 5000 mL / min (sccm).

In addition, the said 1st process and the said 3rd process can be performed at 200-350 degreeC, and the pressure at the time of performing the said 1st process and the said 3rd process can be 133.3-2000 Pa. In this case, the said 2nd process can be performed at the same temperature and the same pressure as the said 1st process and the said 3rd process.

In addition, the present invention is a storage medium storing a program for operating a computer and controlling a film forming apparatus, wherein the program controls the computer to form the film forming apparatus so that the film forming method of the metal film is performed when executed. A storage medium is featured.

According to the present invention, after forming an initial metal film using a metal-containing compound, ammonia, or the like, which has a ligand having a nitrogen-carbon bond in a molecular structure capable of film formation on a substrate, and a structure in which nitrogen in the ligand is coordinated to the metal, Hydrogen gas is supplied into the processing container to perform hydrogen treatment on the substrate to be treated, and then a film of the main metal film using the same metal-containing compound and hydrogen gas is formed thereon. The film can be reliably removed, and when the main metal film is subsequently formed, it is formed as a film containing very few impurities using hydrogen gas as the reducing gas. For this reason, the metal film obtained becomes high purity as a whole. Hydrogen treatment only removes impurities in the thin initial metal film, and a short time treatment is sufficient, and in the main film forming using H ₂ gas as the reducing gas, the film forming rate is higher than that in the case of using NH ₃ gas, thus reducing gas. As a result, the throughput can be remarkably increased compared to the conventional method of forming a film by using NH ₃ and annealing after film formation.

1 is a schematic diagram showing an example of a film forming apparatus for performing a metal film forming method according to an embodiment of the present invention.
2 is a timing chart showing a sequence of a metal film deposition method according to an embodiment of the present invention.
3A and 3B are diagrams for explaining a mechanism in which impurities are removed from an initial Ni film by hydrogen treatment.
Fig. 4 shows the film thickness by X-ray photoelectron spectroscopy (XPS) of a sample in which a Ni film was formed on a Si wafer by using Ni (II) (tBu-AMD) ₂ as a raw material for forming a film and NH ₃ as a reducing gas. It is a figure which shows the result of elemental analysis of the direction.
Fig. 5 shows a sample in which a Ni film is formed on a Si wafer using Ni (II) (tBu-AMD) ₂ as a raw material for film formation and NH ₃ as a reducing gas, and then subjected to hydrogen treatment by supplying H ₂ gas. Fig. 1 shows the results of elemental analysis in the film thickness direction by X-ray photoelectron spectroscopy (XPS).

EMBODIMENT OF THE INVENTION Below, the Example of this invention is described with reference to an accompanying drawing.

In this embodiment, a case where a nickel film is formed as a metal film will be described. 1 is a schematic diagram showing an example of a film forming apparatus for performing a metal film forming method according to an embodiment of the present invention.

The film forming apparatus 100 has a substantially cylindrical chamber 1 that is hermetically sealed, and the susceptor 2 for horizontally supporting the wafer W, which is a substrate to be processed, is exhausted as described later. It is arrange | positioned in the state supported by the cylindrical support member 3 which extends from the bottom part of a thread to the center lower part. The susceptor 2 is made of ceramics such as AlN. A heater 5 is embedded in the susceptor 2 and a heater power supply 6 is connected to the heater 5. On the other hand, the thermocouple 7 is provided in the vicinity of the upper surface of the susceptor 2, and the signal of the thermocouple 7 is transmitted to the heater controller 8. The heater controller 8 transmits a command to the heater power supply 6 according to the signal of the thermocouple 7, controls the heating of the heater 5, and controls the wafer W to a predetermined temperature. Above the heater 5 inside the susceptor 2, an electrode 27 for applying high frequency power is embedded. The high frequency power source 29 is connected to the electrode 27 via a matching unit 28. The high frequency power is applied to the electrode 27 as necessary to generate a plasma, and to perform plasma CVD. It is. In addition, three wafer lifting pins (not shown) are provided in the susceptor 2 so as to protrude and dent with respect to the surface of the susceptor 2, and the susceptor 2 is conveyed when the wafer W is conveyed. It is in the state which protruded from the surface of).

A circular hole 1b is formed in the ceiling wall 1a of the chamber 1, and the shower head 10 is fitted in to protrude into the chamber 1 therefrom. The shower head 10 is for discharging the gas for film formation supplied from the gas supply mechanism 30 mentioned later into the chamber 1, and the 1st introduction path 11 which introduces the film-forming raw material gas in the upper part is carried out. And a second introduction passage 12 for introducing NH ₃ gas and H ₂ gas as a reaction gas (reduction gas).

The nickel-containing compound used as the film forming raw material gas has a ligand having a nitrogen-carbon bond in its molecular structure, and has a structure in which nitrogen in the ligand is coordinated with nickel, for example, Ni (II) N shown in FIG. 1. , N'-dibutyl butyl amidate (Ni (II) (tBu-AMD) ₂ ). Examples of the nickel amidate include, but are not limited to, Ni (II) N, N'-diisopropyl amidate (Ni (II) (iPr-AMD) ₂ ), Ni (II) N, N'-diethyl amidate (Ni (II) (Et-AMD) ₂ ), Ni (II) N, N'-dimethyl amidate (Ni (II) (Me-AMD) ₂ ), and the like.

Inside the shower head 10, spaces 13 and 14 are formed in two stages up and down. The first introduction passage 11 is connected to the upper space 13, from which the first gas discharge passage 15 extends to the bottom of the shower head 10. A second introduction path 12 is connected to the lower space 14, from which the second gas discharge path 16 extends to the bottom of the shower head 10. That is, the shower head 10 is configured such that nickel amidate as the film forming raw material gas, NH ₃ gas, and H ₂ gas are independently discharged from the discharge paths 15 and 16.

The exhaust chamber 21 which protrudes downward is provided in the bottom wall of the chamber 1. An exhaust pipe 22 is connected to the side of the exhaust chamber 21, and an exhaust device 23 having a vacuum pump, a pressure control valve, or the like is connected to the exhaust pipe 22. By operating this exhaust device 23, it is possible to bring the chamber 1 into a predetermined reduced pressure state.

The sidewall of the chamber 1 is provided with a carry-in / out port 24 for carrying in and out of the wafer W, and a gate valve 25 for opening and closing the carry-in and out ports 24. Moreover, the heater 26 is provided in the wall part of the chamber 1, and it is possible to control the temperature of the inner wall of the chamber 1 at the time of film-forming process.

The gas supply mechanism 30 is a nickel amidate (Ni-AMD), which is a nickel-containing compound having a ligand having a nitrogen-carbon bond in its molecular structure and having a structure in which nitrogen in the ligand is coordinated with nickel, For example, it has the film-forming raw material tank 31 which stores Ni (II) N and N'-dibutyl butyl amidate (Ni (II) (tBu- AMD) ₂ ) in the state melt | dissolved in the solvent. A heater 31a is provided around the film forming raw material tank 31, and the film forming raw material in the film forming raw material tank 31 can be heated to an appropriate temperature. In addition, when using a liquid thing at normal temperature as a nickel containing compound, it can be stored as it is, without melt | dissolving in a solvent.

The bubbling piping 32 for supplying Ar gas which is a bubbling gas from upper direction is inserted in the film-forming raw material tank 31 so that it may be immersed in film-forming raw material. Ar gas supply source 33 is connected to bubbling piping 32, and the mass flow controller 34 as a flow controller and the valve 35 before and behind are interposed. In the film forming raw material tank 31, a raw material gas sending pipe 36 is inserted from above, and the other end of the raw material gas sending pipe 36 is connected to the first introduction passage 11 of the shower head 10. It is. A valve 37 is provided in the raw material gas delivery pipe 36. Moreover, the heater 38 for preventing the condensation of film-forming raw material gas is provided in the raw material gas sending piping 36. And the Ar gas which is a bubbling gas is supplied to the film-forming raw material, and the film-forming raw material is vaporized by bubbling in the film-forming raw material tank 31, and the film-forming raw material gas produced | generated is the raw material gas delivery piping 36 and 1st introduction. It is fed into the shower head 10 via the furnace 11.

The bubbling pipe 32 and the raw material gas delivery pipe 36 are connected by a bypass pipe 48, and a valve 49 is interposed in the bypass pipe 48. Valves 35a and 37a are interposed on the downstream side of the connection portion of the bypass piping 48 in the bubbling piping 32 and the raw material gas delivery piping 36. Then, the argon gas from the Ar gas supply source 33 is discharged from the bubbling pipe 32, the bypass pipe 48, and the source gas delivery pipe 36 by closing the valves 35a and 37a and closing the valve 49. ), It is possible to supply into the chamber 1 as a purge gas or the like.

A pipe 40 is connected to the second introduction passage 12 of the shower head 10, and a valve 41 is provided in the pipe 40. The pipe 40 branches into branch pipes 40a and 40b, the NH ₃ gas supply source 42 is connected to the branch pipe 40a, and the H ₂ gas supply source 43 is connected to the branch pipe 40b. It is. In addition, the branch pipe 40a is interposed with the mass flow controller 44 as a flow controller and the valve 45 before and after, and the branch pipe 40b has the mass flow controller 46 as a flow controller and the valve before and behind it. (47) is interposed. In addition, it is possible to use hydrazine or NH ₃ derivatives, hydrazine derivatives in place of NH _3.

In addition, when plasma CVD is performed by applying a high frequency power to the electrode 27 as required, although not shown, branch pipes are additionally formed in the pipe 40, and the mass flow controller and the front and rear of the branch pipes are additionally provided. It is preferable to provide an Ar gas supply source for plasma ignition through the valve of.

This film-forming apparatus has the control part 50 which controls each structure part, specifically a valve, a power supply, a heater, a pump, etc. The control unit 50 has a process controller 51 having a microprocessor (computer), a user interface 52, and a storage unit 53. The process controller 51 is configured such that each component of the film formation apparatus 100 is electrically connected and controlled. The user interface 52 is connected to the process controller 51, and the operator visualizes and displays the operation status of each component of the film forming apparatus, and a keyboard for inputting a command or the like to manage each component of the film forming apparatus. It consists of a display. The storage unit 53 is also connected to the process controller 51, and in this storage unit 53, a control program for realizing various processes executed in the film forming apparatus 100 under the control of the process controller 51, or According to the processing conditions, a control program for executing a predetermined process, that is, a processing recipe, various databases, or the like is stored in each component part of the film forming apparatus 100. The processing recipe is stored in a storage medium (not shown) in the storage unit 53. The storage medium may be fixedly installed, such as a hard disk, or may be portable such as a CD-ROM, a DVD, a flash memory, or the like. In addition, the recipe may be appropriately transmitted from another apparatus through, for example, a dedicated line.

If necessary, the film forming apparatus 100 is controlled under the control of the process controller 51 by calling a predetermined process recipe from the storage 53 and executing the process controller 51 by an instruction from the user interface 52. The desired processing in is performed.

Next, a method of forming a metal film according to an embodiment of the present invention performed by the film forming apparatus 100 will be described.

First, the gate valve 25 is opened, the wafer W is loaded into the chamber 1 via the carry-in port 24 by a conveying device (not shown), and is mounted on the susceptor 2. . Next, the inside of the chamber 1 is exhausted by the exhaust device 23 to make the inside of the chamber 1 at a predetermined pressure, and the susceptor 2 is heated to a predetermined temperature.

In that state, as shown in the timing chart of FIG. 2, nickel amidate (a nickel-containing compound having a ligand having a nitrogen-carbon bond in its molecular structure and having a structure in which nitrogen in the ligand is coordinated to nickel) as a film forming raw material; An initial film forming step (step 1) of supplying NH ₃ gas, which is a reducing gas, to form an initial Ni film, and stopping these gases, introducing H ₂ gas into the chamber 1 to perform hydrogen treatment on the wafer W; The main film forming step (step 3) of introducing a nickel amidate, which is a film forming raw material gas, and forming a main Ni film while continuing the hydrogen treatment step (step 2) and introduction of the H ₂ gas, and the inside of the chamber 1 The purge process (step 4) to purge is performed sequentially.

When the Ni film is formed on the surface of the wafer W (typically, the surface of the Si substrate or the polysilicon film) using nickel amidate as the film forming raw material, no nucleus is generated even when H ₂ is used as the reducing gas. Since Ni is not deposited, NH ₃ or the like is used in the initial film forming step of Step 1 as the reducing gas. That is, in the initial film forming step of step 1, nickel amidate as the film forming raw material stored in the film forming raw material tank 31, for example, Ni (II) N, N'-dibutyl butyl amidate (Ni (II)). Ar gas as a bubbling gas was supplied to (tBu-AMD) ₂ ), and the nickel amidate as the film forming raw material was vaporized by bubbling, and the source gas delivery pipe 36 and the first introduction passage 11, through the showerhead 10, and supplied into the chamber 1, the NH ₃ gas as the reducing gas to the branch pipe (40a), the pipe (40), the second introduction from the NH ₃ gas supply source 42, 12, shower It feeds into the chamber 1 via the head 10. In addition, hydrazine, NH ₃ derivatives, and hydrazine derivatives may be used instead of NH ₃ , which is a reducing gas. In other words, at least one selected from NH ₃ , hydrazine and derivatives thereof can be used as the reducing gas. Monomethyl ammonium can be used as an ammonia derivative, for example, and monomethyl hydrazine and dimethyl hydrazine can be used as a hydrazine derivative. Of these, ammonia is preferred. These are reducing agents having an unshared electron pair, have high reactivity with nickel amidate, and can easily obtain an initial Ni film on the surface of the wafer W even at a relatively low temperature. It is preferable that the film thickness of the initial Ni film formed in such an initial film forming process is 3-15 nm.

As a nickel amidate used as a film-forming raw material, the structure shown in following formula (1) takes Ni (II) N and N'-dibutyl butyl amidate (Ni (II) (tBu- AMD) ₂ ) as an example. Have

That is, an amidate ligand is bonded to Ni which becomes a nucleus, and Ni exists substantially as Ni2 ⁺ .

, For the reduction gas, for example, has a lone pair NH ₃ is coupled with Ni nucleus and is present as Ni ^{+ 2} in the structure of the nickel carbonate amidinyl, amidinyl ligand carbonate is decomposed. As a result, in the initial Ni film, nickel nitride (Ni-N) is formed in the film as an impurity by nickel amidate or N derived from NH ₃ . In addition, Ni-C is also produced as an impurity. Therefore, the initial Ni film produced will have many impurities.

The hydrotreating process of the step 2, the nickel Oh stopping the supply of a MIDI carbonate and NH ₃ gas, and supplying an H ₂ gas into the chamber (1) performs the initial Ni layer hydrotreating the wafer (W) after the film formation. At this time, the H ₂ gas is supplied into the chamber 1 from the H ₂ gas supply source 43 via the branch pipe 40b, the pipe 40, the second introduction path 12, and the shower head 10. In this step 2, the H ₂ gas is supplied first, and the nickel amidate gas and the NH ₃ gas remaining therein are purged by vacuum evacuating the inside of the chamber 1, and then the supply of the H ₂ gas is continued. The pressure in the chamber 1 is controlled to a predetermined pressure. Thus, by supplying H ₂ gas into the chamber 1 and subjecting the wafer W to hydrogen treatment, as shown in FIGS. 3A and 3B, it is an impurity in the Ni film formed by nickel amidate or NH ₃ . Ni-N or Ni-C reacts with H ₂ gas and becomes NH ₃ or CH _{4 and} is removed from the film. As a result, an initial Ni film having few impurities is formed.

In the main film forming step of step 3, the flow rate is adjusted while H ₂ gas is supplied, and the suspended nickel amidate is supplied in the same manner as in step 1. As a result, the nickel amidate is reduced by the H ₂ gas to further deposit Ni on the initial Ni film to form a main Ni film. At this time, impurities in the initial Ni film are removed by the hydrogen treatment in Step 2, and nickel amidate is reduced to H ₂ gas, whereby the main Ni film is formed as a film containing few impurities, so that the obtained Ni film is entirely free of impurities. It is small.

The film thickness in the main film-forming process of step 3 is suitably determined according to the film thickness of the total of the Ni film to be formed, and the film thickness at the time of initial film-forming. The film formation time is preferably determined in advance from the film thickness and the film formation rate.

In the purge step of step 4, the supply of nickel amidate and H ₂ gas is stopped, and the inside of the chamber 1 is evacuated. At this time, Ar gas from the Ar gas supply source 33 is supplied into the chamber 1 as a purge gas through the bubbling piping 32, the bypass piping 48, and the source gas sending piping 36 as needed. You may also

After the purge process is completed, the gate valve is opened, and the wafer W after film formation is carried out through the carry-out port 24 by a transfer device (not shown).

Conventionally, as shown in Patent Document 3, after forming the entire Ni film using nickel amidate as the film forming raw material and NH ₃ as the reducing gas, in order to remove impurities in the Ni film, a hydrogen atmosphere is used. Annealing is performed to remove N in the Ni film. However, when such annealing is performed after film formation, throughput decreases by that amount. In order to obtain a higher purity Ni film, the throughput is further reduced when the film formation and the annealing treatment are repeated a plurality of times. Therefore, in the embodiment of Japanese Patent Application No. 2011-191917, after the initial film formation in the same manner as in the present embodiment, the main film is formed by changing the reducing gas to H ₂ gas.

Thus, performing main film formation after initial film formation is based on the following knowledge.

(1) After forming an initial Ni film by performing initial film formation with nickel amidate as a raw material and NH ₃ as a reducing gas having a non-covalent electron pair, the Ni film can be formed thereon even if H ₂ gas is used as the reducing gas. Do.

(2) When H ₂ is used as the reducing gas, since N does not flow into the film, Ni _x N is not formed and a high purity Ni film can be formed.

(3) By the presence of H ₂ gas, which is a reducing gas, N contained in the initial Ni film can be removed.

(4) When the Ni film is formed on the initial Ni film by using nickel amidate as the raw material and H ₂ as the reducing gas, the film formation rate is higher than that of using nickel amidate and NH ₃ . Is high.

As a result of further examination, however, when the method described in Japanese Patent Application No. 2011-191917 is adopted, in the main film forming step, a high-purity main Ni film is obtained, but Ni-N or Ni- included in the initial Ni film. Impurities, such as C, may not be removed sufficiently, and it turned out that such an impurity worsens the specific resistance of a Ni film | membrane and becomes a cause of the nickel silicide formation defect.

Therefore, in the present embodiment, as described above, the initial film formation is performed by using nickel amidate as the film forming raw material and NH ₃ as the reducing gas having a non-covalent electron pair as step 1, followed by nucleation (forming an initial Ni film). The supply of nickel amidate and NH ₃ gas is stopped and hydrogen treatment is carried out by H ₂ gas to remove impurities of the initial Ni film, and then in step 3, the main film is formed using nickel amidate and H ₂ gas. As a result, impurities in the initial Ni film are removed by the hydrogen treatment in Step 2, and the main Ni film is formed as a film containing very few impurities by reducing nickel amidate to H ₂ gas, so that the obtained Ni film has few impurities. High purity. In addition, the hydrogen treatment of step 2 only removes impurities of a very thin initial Ni film formed as a nucleus, and a short time treatment is sufficient, and in the main film formation using H ₂ gas as the reducing gas, the film formation is performed more than in the case of using NH ₃ gas. Since the rate is high, the throughput can be remarkably increased compared to the conventional method of forming a film using nickel amidate and NH ₃ and annealing after film formation.

The hydrogen treatment process of step 2, the pressure in the chamber (1): 333.3 ~ 13330 Pa (2.5 ~ 100 Torr), the heating temperature of the wafer (W) by the susceptor 2: 160 ~ 500 ℃, H ₂ gas Flow rate: It is preferable to carry out on 25-5000 mL / min (sccm) conditions. Moreover, although processing time depends on these conditions, tens of seconds to several minutes are enough. In addition, the pressure, the temperature, and the H ₂ gas flow rate are preferable because the higher the value within the above range, the higher the throughput.

In the initial film formation step of step 1, the pressure in the chamber 1: 133.3 to 2000 Pa (1 to 15 Torr), the heating temperature (film formation temperature) of the wafer W by the susceptor 2: 200 to 350 ° C. Carrier Ar gas flow rate: 50-500 mL / min (sccm), NH ₃ gas flow rate: 10-2000 mL / min (sccm) is preferable.

In addition, in the main film forming step of Step 3, the pressure in the chamber 1: 133.3 to 2000 Pa (1 to 15 Torr) and the heating temperature (film formation temperature) of the wafer W by the susceptor 2: 200 to 350 C, carrier Ar gas flow rate: 50-500 mL / min (sccm), H ₂ gas flow rate: 50-500 mL / min (sccm) are preferable.

In addition, when performing steps 1-3 in the same chamber as in the present embodiment, it is preferable to perform these steps at the same temperature and pressure from the viewpoint of increasing the throughput. In addition, at least one of these steps 1-3 may be performed in another chamber, and in that case, conditions may be set individually at each step.

In the case where the Ni film is formed on the silicon substrate or the polysilicon according to this embodiment, nickel silicide (NiSi) can be obtained by annealing in an inert gas atmosphere such as Ar gas after the film formation. In this case, in this embodiment, since a Ni film containing few impurities is obtained, no defective formation of nickel silicide occurs, and annealing for silicide formation can be performed in a short time.

Next, the experiment which confirmed the removal effect of the impurity by said step 2 is demonstrated.

Here, a sample formed by forming a Ni film (corresponding to an initial Ni film) of about 30 nm on a Si wafer using Ni (II) (tBu-AMD) ₂ as a film forming raw material and NH ₃ as a reducing gas; After forming the Ni film in the same manner, the composition in the film thickness direction was analyzed by X-ray photoelectron spectroscopy (XPS) on the sample subjected to hydrogen treatment by supplying H ₂ gas. The results are shown in FIGS. 4 and 5. In these figures, the horizontal axis represents the etching cycle in the thickness direction and is about 1.7 nm etched in one etching. The hydrogen treatment was carried out under the conditions of a wafer temperature of 250 ° C., a pressure of 1333 Pa (10 Torr), a H ₂ gas flow rate of 500 mL / min (sccm) and a processing time of 180 sec.

As a result, as shown in FIG. 4, in the state where the Ni film is formed, N or C is contained as a total of 10 atomic% or more as impurities in the film, whereas as shown in FIG. 5, N and C are treated by performing hydrogen treatment. Was found to be mostly removed.

In addition, this invention is not limited to the said Example, A various deformation | transformation is possible. For example, in the above embodiment, Ni (II) (tBu−) is a metal-containing compound which has a ligand having a nitrogen-carbon bond in its molecular structure and a structure in which nitrogen in the ligand is coordinated to the metal. Although the case of forming a Ni film using AMD) ₂ is illustrated, other metals, such as Ti (titanium), Co (cobalt), Cu (copper), Ru (ruthenium), and Ta (tantalum), are formed using the same metal compound. It is also applicable to forming a metal film such as). In particular, cobalt amidate has the same structure as nickel amidate, and when a Co film is formed using cobalt amidate, the effect is approximately the same as that of forming a Ni film using the nickel amidate. It is assumed to be obtained. In addition, as a film-forming raw material, when forming a Ni film, another nickel amidate can also be used, and also when forming another metal, various amidate-type compounds can be used. Moreover, as long as it is a metal containing compound which has a ligand which has a nitrogen-carbon bond in molecular structure, and nitrogen in a ligand has a structure which coordinated to a metal, it may be other than an amidate type compound.

In addition, the structure of the film-forming apparatus is not limited to the said Example, The supply method of the film-forming raw material does not need to be limited to the bubbling same as the said Example, Various methods can be applied.

In addition, although the case where a semiconductor wafer is used as a to-be-processed substrate was demonstrated, it is not limited to this, Other board | substrates, such as a flat panel display (FPD) substrate, may be sufficient.

1: chamber
2: susceptor
5: heater
10: shower head
30: gas supply mechanism
31: film forming raw material tank
42: NH ₃ gas source
43: H ₂ gas source
50:
51: Process controller
53: memory
W: Semiconductor wafer

Claims (11)

The film-forming raw material which consists of a metal-containing compound which arrange | positions a to-be-processed board | substrate in a process container, has a ligand which has a nitrogen-carbon bond in a molecular structure, and has a structure which nitrogen in a ligand coordinated to a metal on a to-be-processed substrate, and ammonia A first step of supplying a reducing gas comprising at least one selected from hydrazine and derivatives thereof, and forming an initial metal film by CVD;
Thereafter, a second step of supplying hydrogen gas into the processing container to perform hydrogen treatment on the substrate to be processed;
On the initial metal film formed on the substrate to be treated, a film forming raw material comprising a metal-containing compound having a ligand having a nitrogen-carbon bond in its molecular structure and having a structure in which nitrogen in the ligand is bound to the metal, and a reducing gas composed of hydrogen gas And a third step of forming a main metal film by CVD. The method according to claim 1,
The metal-containing compound is a metal amidate-based compound, characterized in that the metal film deposition method. 3. The method of claim 2,
The metal amidate compound is nickel amidate, and the metal film is a nickel film. The method of claim 3,
The said 2nd process is performed at 160-500 degreeC, The film-forming method of the metal film characterized by the above-mentioned. The method of claim 3,
The pressure at the time of performing said 2nd process is 333.3-13330 Pa, The metal film-forming method characterized by the above-mentioned. 6. The method according to any one of claims 3 to 5,
The hydrogen gas flow rate at the time of performing the said 2nd process is 25-5000 mL / min (sccm), The metal film film-forming method characterized by the above-mentioned. 6. The method according to any one of claims 3 to 5,
The said 1st process and the said 3rd process are performed at 200-350 degreeC, The metal film-forming method characterized by the above-mentioned. 6. The method according to any one of claims 3 to 5,
The pressure at the time of performing the said 1st process and the said 3rd process is 133.3-2000 Pa, The metal film-forming method characterized by the above-mentioned. 8. The method of claim 7,
The said 2nd process is performed at the same temperature as the said 1st process and the said 3rd process, The metal film film-forming method characterized by the above-mentioned. 9. The method of claim 8,
The said 2nd process is performed at the same pressure as the said 1st process and the said 3rd process, The metal film film-forming method characterized by the above-mentioned. A storage medium storing a program for operating on a computer and controlling a film forming apparatus, wherein the program is formed on the computer so that the film forming method of the metal film according to any one of claims 1 to 5 is executed at the time of execution. A storage medium for controlling the device.

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