JPWO2011013812A1 - Semiconductor device manufacturing apparatus and semiconductor device manufacturing method - Google Patents

Abstract

A tungsten hexafluoride gas and a monosilane gas are supplied to a vacuum chamber of a film forming chamber containing the substrate. Then, a thin film made of tungsten is selectively formed on a portion having higher conductivity than other portions of the substrate. Prior to the film formation process, monosilane gas is supplied into the vacuum chamber, and the monosilane gas is adsorbed on a highly conductive portion of the substrate. Thereafter, excess monosilane is evacuated from the vacuum chamber and a film forming process is performed. Further, during the film forming process, tungsten hexafluoride gas and monosilane gas are supplied to the vacuum chamber so that the partial pressure of tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of monosilane gas.

Description

  The present invention relates to a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method, and in particular, a semiconductor device is manufactured using a selective chemical vapor deposition method (selective CVD method) in which tungsten is selectively deposited only at a desired position. The present invention relates to an apparatus and a manufacturing method thereof.

  In a semiconductor device including a substrate made of a semiconductor material such as silicon, a plurality of components such as active elements and passive elements are stacked on the substrate in a state of being sandwiched between insulating films. In order to electrically connect a plurality of components, a plurality of through holes are formed in the insulating film so as to connect the components. In particular, a contact hole for electrically connecting the active element and the multilayer wiring is provided between the active element provided on the substrate and the multilayer wiring stacked on the substrate. Further, in a multilayer wiring structure having an insulating layer between wirings, a via hole for electrically connecting the wirings is provided. A metal material such as molybdenum (Mo) or tungsten (W) is embedded in the contact hole and the via hole. The embedded metal material functions as a wiring that electrically connects between the active element and the wiring or between the wirings in the multilayer wiring structure. In recent years, tungsten has been widely used as a wiring material from the viewpoint that it can suppress a parasitic effect which is an undesirable interaction between elements and has high stability against heat.

  A blanket CVD method has been widely used as a method for forming wiring. In the blanket CVD method, a titanium nitride (TiN) film is formed as a glue layer for growing a wiring material on the entire surface of an insulating layer in which contact holes or via holes are formed. Then, a thin film made of a wiring material such as tungsten is formed on the entire surface of the glue layer. Thereafter, unnecessary portions of the wiring material are removed. As described above, in the blanket CVD method, a tungsten thin film is formed on the entire surface of the insulating layer, so that a tungsten film grows around the opening periphery of the contact hole or via hole, and so-called overhang occurs, which narrows the opening area. When the overhang occurs, the amount of tungsten that can enter the contact hole or via hole is limited, so that the contact hole or via hole is not sufficiently filled. The contact hole or via hole filling defect becomes more prominent when the diameter of the contact hole or via hole is smaller, especially when the diameter is 40 nm or less. In addition, in the blanket CVD method, a removal process after film formation is essential, and accordingly, the number of manufacturing steps of the semiconductor device increases and the manufacturing cost increases due to the material to be removed.

  For this reason, in recent years, as a technique for forming a thin film made of a wiring material only in a part such as a contact hole or a via hole, a selective CVD method capable of achieving both a reduction in manufacturing steps and a reduction in manufacturing cost has been implemented (Patent Document 1). reference).

Japanese Patent Laid-Open No. 10-229054

As a method for forming a tungsten thin film by a selective CVD method, a SiH ₄ reduction method is known in which tungsten hexafluoride (WF ₆ ) gas and monosilane (SiH ₄ ) gas are supplied into a vacuum chamber to form a tungsten thin film. It has been. As the supply pattern of tungsten hexafluoride gas and monosilane gas to the vacuum chamber in the SiH ₄ reduction method, the following three are conceivable.

(A) Tungsten hexafluoride gas and monosilane gas are supplied simultaneously.
(B) A tungsten hexafluoride gas is supplied prior to the monosilane gas.
(C) A monosilane gas is supplied prior to the tungsten hexafluoride gas.

  Among these, if the supply of tungsten hexafluoride gas and monosilane gas is performed simultaneously as in the pattern (A), nucleus growth in the initial stage of the film forming process is difficult to occur. For this reason, the film-forming reaction of tungsten is rate-limited at the initial stage, and the production process of the semiconductor device is stagnated. In addition, when a tungsten hexafluoride gas is supplied prior to the monosilane gas as in the pattern (B) and silicon constituting the semiconductor substrate is used as a film formation target, the nucleus growth of tungsten is promoted, but the six fluorine atoms are promoted. The following reaction proceeds between tungsten silicide and silicon on the surface of the semiconductor substrate. As a result, the surface of the semiconductor substrate is eroded.

2WF ₆ + 3Si → 2W + 3SiF ₄
When the monosilane gas is supplied prior to the tungsten hexafluoride gas as in the pattern (C), highly reactive monosilane molecules scattered on the surface of the semiconductor substrate are contained in the tungsten hexafluoride gas supplied thereafter. Reacts with molecules. For this reason, the nucleus growth of tungsten is promoted. However, the monosilane gas also exists on the surface of the insulating film in addition to the part where the wiring is formed. For this reason, there is a possibility that the tungsten thin film may be formed in another part different from the desired part.

  An object of the present invention is to provide a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method capable of forming a tungsten thin film with high selectivity at a desired position using a selective CVD method.

  In order to solve the above problems, according to the first aspect of the present invention, tungsten hexafluoride gas and monosilane gas are supplied to a vacuum chamber containing a substrate, so that it is more conductive than other portions of the substrate. Provided is a method for manufacturing a semiconductor device that executes a film forming process for selectively forming a thin film made of tungsten at a high portion.

  In this manufacturing method, before the film forming process, monosilane gas is supplied into the vacuum chamber to adsorb the monosilane gas to a highly conductive part, and then the excess monosilane is exhausted from the vacuum chamber and the film forming process is performed. In doing so, tungsten hexafluoride gas and monosilane gas are supplied to the vacuum chamber so that the partial pressure of tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of monosilane gas.

  In order to solve the above problems, according to a second aspect of the present invention, a vacuum chamber capable of accommodating a substrate, a first gas supply unit for supplying tungsten hexafluoride gas to the vacuum chamber, and a vacuum chamber A second gas supply unit for supplying monosilane gas to the substrate, supplying tungsten hexafluoride gas and monosilane gas to a vacuum chamber in which the substrate is accommodated, and tungsten from a portion having higher conductivity than other portions of the substrate. There is provided a semiconductor device manufacturing apparatus for performing a film forming process for selectively forming a thin film.

  In this manufacturing apparatus, before the film forming process, the monosilane gas is supplied into the vacuum chamber to adsorb the monosilane gas to a highly conductive part, and then the excess monosilane is exhausted from the vacuum chamber and the film forming process is performed. In this case, tungsten hexafluoride gas and monosilane gas are supplied to the vacuum chamber so that the partial pressure of tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of monosilane gas.

The top view which shows the manufacturing apparatus of the semiconductor device in one Embodiment of this invention. The fragmentary sectional view which shows the film-forming chamber. 6 is a timing chart showing timing for supplying gas to the film formation chamber. The graph which shows the effect of the monosilane gas supply process performed prior to the film-forming process, and the exhaust process of excess monosilane.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, a pair of loading / unloading ports 11 a and 11 b for introducing and removing a substrate are provided adjacent to each other in a semiconductor device manufacturing apparatus. Pre-processing chambers 12a and 12b are provided at positions adjacent to the loading / unloading ports 11a and 11b. In the pretreatment chambers 12a and 12b, the surface of the substrate is cleaned as a treatment before forming the tungsten thin film on the substrate. Further, film forming chambers 13a and 13b are provided at positions adjacent to the pretreatment chambers 12a and 12b. In the film forming chambers 13a and 13b, a film forming process for forming a tungsten thin film on the substrate is executed. A heat treatment chamber 14 is provided between the film forming chambers 13a and 13b. In the heat treatment chamber 14, a heat treatment is performed in which predetermined heat is applied to the pretreated substrate. In a semiconductor device manufacturing apparatus, a pair of loading / unloading ports 11a and 11b and five chambers 12a, 12b, 13a, 13b, and 14 form an annular shape.

  In the center of the manufacturing apparatus, there is a transfer chamber 15 through which the substrate is moved from one of the two loading / unloading ports 11a, 11b and the five chambers 12a, 12b, 13a, 13b, 14 to the next process. Is provided.

  When manufacturing a semiconductor device, first, a substrate to be subjected to a film forming process is introduced into the manufacturing apparatus from the carry-in / carry-out ports 11a and 11b. The loading / unloading ports 11a and 11b have the same function with respect to the introduced substrate. Hereinafter, a case where a substrate is introduced from the loading / unloading port 11a will be described. An insulating film is provided on the surface of the substrate where the active element is formed, and a contact hole for forming a wiring or a via hole constituting a multilayer wiring is provided in the insulating film.

  After the substrate is introduced into the loading / unloading port 11a, the substrate is first transported to the pretreatment chamber 12a via the transfer chamber 15. In the pretreatment chamber 12a, for example, an oxide layer that is a reaction product with oxygen in the atmosphere is removed from the surface of the substrate at the bottom of the contact hole provided in the insulating layer or the surface of the wiring at the bottom of the via hole. Is done. The substrate is pretreated in the pretreatment chamber 12 a and then transferred to the heat treatment chamber 14 via the transfer chamber 15. In the heat treatment chamber 14, in order to reduce the resistance at the interface between the thin film made of tungsten and the base, heat treatment is performed on the base exposed by the above pretreatment. After the heat treatment, the substrate is transferred to the film forming chamber 13a through the transfer chamber 15. In the film forming chamber 13a, a tungsten thin film is selectively formed in contact holes and via holes provided in the substrate, that is, parts having higher conductivity than other parts. Is done.

  After the film formation process, the substrate is transferred to the loading / unloading port 11a via the transfer chamber 15 and then unloaded from the manufacturing apparatus. When the substrate is carried into the manufacturing apparatus from the carry-in / carry-out port 11b, the substrate is pretreated by the pretreatment chamber 12b, the heat treatment by the heat treatment chamber 14, and the film formation chamber 13b, as in the case of being carried in from the carry-in / carry-out port 11a. After the film forming process is sequentially performed, the film is carried out of the manufacturing apparatus from the carry-in / carry-out port 11b.

Next, the configuration of the film forming chambers 13a and 13b and the film forming process executed by the film forming chambers 13a and 13b will be described with reference to FIGS.
As shown in FIG. 2, the film forming chambers 13 a and 13 b include a vacuum chamber 21. A substrate stage 22 on which the substrate S is placed is provided in the vacuum chamber 21. The vacuum chamber 21 is provided with a source gas port P1 for supplying tungsten hexafluoride (WF ₆ ) gas and monosilane (SiH ₄ ) gas which are source gases. Below the source gas port P1, a shower head 23 for uniformly diffusing the gas supplied from the source gas port P1 into the vacuum chamber 21 is provided.

  One pipe is connected to the raw material gas port P1, and this pipe branches into a monosilane gas pipe and a tungsten hexafluoride gas pipe. The monosilane gas pipe and the tungsten hexafluoride gas pipe are provided with flow rate controllers MFC1 and MFC3 for adjusting the gas flow rate, respectively. The flow rate control units MFC1 and MFC3 execute flow rate control of gas used for the film forming process and the cleaning process. In the cleaning process, the tungsten thin film adhering to the wall in the vacuum chamber 21 and the member such as the substrate stage 22 by the film forming process is removed by fluorine gas which is a cleaning gas.

  An inert gas pipe for introducing argon (Ar) gas, which is an inert gas, into the monosilane gas pipe is branched from the flow rate control unit MFC1 of the monosilane gas pipe from the downstream side. Further, an inert gas pipe for introducing argon gas, which is an inert gas, into the tungsten hexafluoride gas pipe is branched from the downstream side of the flow rate control unit MFC3 of the tungsten hexafluoride gas pipe. . Each of the above inert gas pipes is provided with flow rate control units MFC2 and MFC4 for adjusting the flow rate of the argon gas. The flow control units MFC2 and MFC4 execute flow control of an inert gas used for the film forming process and the cleaning process. In the present embodiment, the flow rate control unit MFC2 and the inert gas pipe connected thereto constitute a second inert gas supply unit. The flow rate control unit MFC4 and the inert gas pipe connected thereto constitute a first inert gas supply unit. The monosilane gas pipe and the flow rate control unit MFC1 constitute a monosilane gas supply unit. The monosilane gas supply unit and the second inert gas supply unit constitute a second gas supply unit. The tungsten hexafluoride gas pipe and the flow rate control unit MFC3 constitute a tungsten hexafluoride gas supply unit. In addition, the tungsten hexafluoride gas supply unit and the first inert gas supply unit constitute a first gas supply unit.

A high frequency power supply 24 for applying a high frequency electric field into the vacuum chamber 21 is connected to the substrate stage 22. The gas introduced into the vacuum chamber 21 is turned into plasma by the high frequency electric field. The vacuum chamber 21 is provided with a cleaning gas port P2 for introducing a cleaning gas. In the vacuum chamber 21, the film forming process using the source gas and the cleaning process are alternately repeated. A cleaning gas pipe for supplying fluorine (F ₂ ) gas as a cleaning gas and argon gas as an inert gas to the vacuum chamber 21 at the same time is connected to the cleaning gas port P2. The cleaning gas pipe is provided with a flow rate control unit MFC5.

  A turbo pump 25 is connected to the vacuum chamber 21 via an exhaust port P3. When the turbo pump 25 is driven, the internal pressure of the vacuum chamber 21 is reduced to a pressure suitable for the film forming process or the cleaning process. The vacuum chamber 21, the piping through which various gases flow, and the substrate stage 22 are each provided with a temperature control mechanism for maintaining the temperature of the inner wall, piping, and substrate S of the vacuum chamber 21 at a predetermined temperature. Yes.

The substrate S is carried into the film forming chambers 13 a and 13 b after undergoing pretreatment in the pretreatment chambers 12 a and 12 b and heat treatment in the heat treatment chamber 14. The substrate S is heated to a predetermined temperature by a temperature control mechanism provided on the substrate stage 22 while being placed on the substrate stage 22 in the film forming chambers 13a and 13b. Thereafter, tungsten hexafluoride gas and monosilane gas are uniformly diffused from the shower head 23 and supplied to the vacuum chamber 21. The reduction reaction of tungsten hexafluoride by monosilane represented by the following reaction formula proceeds on the substrate S at a site with relatively high conductivity. That is, film formation by the selective CVD method is executed.
・ 2WF ₆ + 3SiH ₄ → 2W + 3SiF ₄ + 3H ₂
Alternatively, WF ₆ + 2SiH ₄ → W + 2SiHF ₃ + 3H ₂
A portion having a relatively high conductivity in the substrate S varies depending on a manufacturing process in which the selective CVD method is used. For example, when the selective CVD method is used in the contact wiring formation process, the surface of the substrate to be deposited is covered with an insulating film having a contact hole, and a MOS transistor or the like formed on the surface of the substrate as an active element. The impurity diffusion region is exposed from the contact hole. In this case, a highly conductive portion of the substrate S is an impurity diffusion region at the bottom of the contact hole, and a tungsten thin film is selectively formed on this portion. Apart from this, when the selective CVD method is used in the via wiring formation process, the surface of the substrate to be deposited is covered with an insulating film having via holes, and a part of the lower layer wiring is exposed from the via holes. Yes. In this case, a highly conductive portion of the substrate S is a wiring at the bottom of the via hole, and a tungsten thin film is selectively formed on this portion.

When the above film forming process is performed on the plurality of substrates S, fluorine gas and argon gas are supplied from the cleaning gas pipe to the vacuum chamber 21, and a high-frequency electric field from the high-frequency power source 24 is generated in the vacuum chamber 21. And the cleaning process is executed. At this time, the tungsten thin film attached to the inner wall of the vacuum chamber 21 reacts with the plasma using fluorine gas, and tungsten hexafluoride, trifluorosilane (SiHF ₃ ), tetrafluorosilane (SiF ₄ ), or hydrogen fluoride ( Fluoride such as (HF) is produced. And the produced | generated fluoride is removed from the inside of the vacuum chamber 21 with argon gas.

  By the way, in the film formation process by the selective CVD method, the following three can be considered as supply patterns of tungsten hexafluoride gas and monosilane gas to the film formation chambers 13a and 13b.

(A) Tungsten hexafluoride gas and monosilane gas are supplied simultaneously.
(B) A tungsten hexafluoride gas is supplied prior to the monosilane gas.
(C) A monosilane gas is supplied prior to the tungsten hexafluoride gas.

In the case of the pattern (A), the nucleus growth in the initial stage of the film forming process hardly occurs, and the film forming speed of tungsten is limited. In the case of pattern (B), the following reaction proceeds between tungsten hexafluoride supplied in advance of monosilane gas and silicon on the surface of the substrate. As a result, the growth rate at the initial stage of film formation is improved, but the surface of the substrate is eroded.
・ 2WF ₆ + 3Si → 2W + 3SiF ₄
In the case of pattern (C), when monosilane gas is supplied prior to tungsten hexafluoride gas, monosilane molecules adsorbed on the surface of the substrate react with molecules in tungsten hexafluoride gas supplied thereafter. For this reason, the growth rate of tungsten in the initial stage of film formation is improved. However, the monosilane gas is also present around the contact hole and via hole on the surface of the insulating film in addition to the contact hole and via hole formed in the insulating film. For this reason, there is a possibility that monosilane and tungsten hexafluoride react in another part different from the desired part to form a tungsten thin film.

  In the present embodiment, as in the pattern (C), the monosilane gas supply process is executed before the film formation process, and the surplus monosilane present in the film formation chambers 13a and 13b after the monosilane gas supply process, that is, Then, an exhausting process for removing monosilane existing in a different part from the part where the tungsten thin film is formed from the film forming chambers 13a and 13b is executed.

  Hereinafter, the execution timing of the monosilane gas supply process, the exhaust process and the film forming process executed in the film forming chambers 13a and 13b, and the processing conditions thereof will be described with reference to FIGS.

FIG. 3 shows supply periods of various gases during the monosilane gas supply process, the exhaust process, and the film formation process performed in the film formation chambers 13a and 13b. 3 (a), (b), (c), (d), and (e) show monosilane (SIH ₄ ) gas, argon (Ar) gas, tungsten hexafluoride (WF ₆ ) gas, hexafluoride to the monosilane gas pipe. The supply period of argon gas to the tungsten gas pipe and the partial pressures of tungsten hexafluoride gas and monosilane gas in the film forming chamber are shown, respectively.

As shown in FIG. 3, monosilane gas is supplied from the monosilane gas pipe and argon gas is supplied from the tungsten hexafluoride gas pipe into the vacuum chamber 21 from timing t1 to timing t2. The monosilane gas is adsorbed at a site with high conductivity on the substrate S and also exists at other sites. In the monosilane gas supply process, for example, the flow rate of monosilane gas is 5.9 × 10 ³ Pam ³ / s (10 sccm), the flow rate of argon gas is 11.8 × 10 ³ Pam ³ / s (20 sccm), and the internal pressure of the vacuum chamber 21 Is set to 0.4 Pa and maintained for 15 seconds.

Thereafter, at timing t2 to timing t3, argon gas is supplied from the monosilane gas pipe and argon gas is continuously supplied from the tungsten hexafluoride gas pipe. By supplying argon gas into the vacuum chamber 21 in this way, excess silicon that does not contribute to the formation of the tungsten thin film in the contact hole or via hole is removed. In the exhaust treatment, for example, the flow rate of argon gas in the monosilane gas pipe and the tungsten hexafluoride pipe is set to 8.9 × 10 ³ Pam ³ / s (15 sccm), and the internal pressure of the vacuum chamber 21 is set to 0.4 Pa. Hold for 1 second.

Thereafter, monosilane gas and tungsten hexafluoride gas are supplied into the vacuum chamber 21 from timing t3 to timing t4. Thereby, the film forming process is started, and a tungsten thin film is selectively formed with respect to the contact hole or via hole of the substrate. In this film forming process, for example, the flow rate of tungsten hexafluoride gas is 11.8 × 10 ³ Pam ³ / s (20 sccm), the flow rate of monosilane gas is 5.9 × 10 ³ Pam ³ / s (10 sccm), and vacuum. While maintaining the internal pressure of the tank 21 at 0.4 Pa, the tungsten hexafluoride gas and the monosilane gas are adjusted so that the partial pressure of the tungsten hexafluoride gas in the film forming chambers 13a and 13b is higher than the partial pressure of the monosilane gas. It is supplied into the vacuum chamber 21.

  The inventor of this application selectively forms the tungsten thin film at a deposition rate of 30 nm / min when the monosilane gas supply process and the exhaust process from timing t2 to timing t3 are performed under the above conditions from timing t1 to timing t2. Confirmed that it will be. Therefore, a tungsten thin film having a desired thickness can be selectively obtained only by appropriately selecting the film formation time.

Such a series of treatments is applied to various products of reaction products and gas components other than tungsten represented by the chemical formula of SiH _x F _y such as trifluorosilane (SiHF ₃ ) and hexafluorosilicic acid (SiH ₂ F ₆ ). In order to suppress adsorption, the vacuum chamber 21 and the piping are each heated by the temperature control mechanism so that the temperature of the inner wall of the vacuum chamber 21 and the piping for supplying various gases is maintained at 80 ° C. In addition, the substrate stage 22 is heated by the temperature adjustment mechanism so that the temperature of the substrate S placed on the substrate stage 22 is maintained at 280 ° C.

Next, the effects obtained by the monosilane gas supply process performed before the film forming process and the exhaust process for exhausting excess monosilane will be described with reference to FIG.
FIG. 4 shows the influence of the monosilane gas supply time and the presence or absence of the exhaust treatment on the selectivity during the film formation process. The graph of FIG. 4 is, in order from the left side, “no monosilane gas supply treatment”, “no monosilane gas supply / exhaust treatment”, “no monosilane gas supply / exhaust treatment”, “monosilane gas supply / exhaust treatment for 5 seconds” The number of occurrences of selectivity breakage under each condition of “Yes” and “With monosilane gas supplied for 15 seconds / exhaust treatment” is shown. The selectivity breakage indicates the number of tungsten nuclei having a nucleus size of 80 nm or more existing per 200 mm wafer.

  As shown in FIG. 4, when the monosilane gas was not supplied before the film forming process, the selectivity breakage was 10 or more and less than 100. Moreover, when the monosilane gas supply process was performed for 1 second before the film-forming process, the selectivity breaking was 1000 or more and less than 10,000. Moreover, when the monosilane gas supply process was performed for 5 seconds before the film-forming process, the selectivity breaking was 10,000 or more and less than 100,000. On the other hand, when the exhaust process was performed to remove excess monosilane in the vacuum chamber 21 and the monosilane gas supply process was performed for 5 seconds, the selectivity breakage was 10 or more and less than 100. In addition, when the exhaust gas treatment and the monosilane gas supply process were executed for 15 seconds, the selectivity was broken by several tens.

  As described above, if the monosilane gas supply process is performed before the film formation process and then the exhaust process is performed, it is possible to suppress the breaking of selectivity to the same extent as when the monosilane gas supply process is not performed. Further, when the conditions of the monosilane gas supply process are the same, for example, by supplying the monosilane gas for 5 seconds and performing the exhaust process after the monosilane gas supply process, it is possible to suppress the selectivity break to about 1/1000. .

According to this embodiment, the following effects can be achieved.
(1) The monosilane gas supply process is performed before the film formation process, and then the exhaust process is performed, so that monosilane adsorbed on the highly conductive portion of the substrate S and tungsten hexafluoride supplied during the film formation process are obtained. The gas can be reacted. Thereby, tungsten nucleus growth in the initial stage of the film forming process is promoted. In addition, after the monosilane gas supply process and before the film formation process, monosilane that has not been adsorbed to the highly conductive portion of the substrate S is exhausted from the film formation chambers 13a and 13b. Thereby, the monosilane which exists on the insulating layer which does not correspond to a part with high electroconductivity can be reduced compared with the case where exhaust processing is not performed. Therefore, on the substrate S, a tungsten thin film can be formed only in a portion having high conductivity, and the selectivity breaking during the so-called film formation process can be suppressed. Therefore, a thin film made of tungsten can be formed at a desired position with good selectivity. The effect of suppressing the selectivity breaking becomes more prominent when the film forming process is performed under the condition that the partial pressure of tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of monosilane gas.

  (2) At the time of exhaust processing for exhausting monosilane gas, argon gas is supplied from the tungsten hexafluoride gas pipe and the monosilane gas pipe, respectively. Thereby, the inert gas collides with the excess monosilane gas, and the exhaust effect of the monosilane gas is improved. Therefore, since excess monosilane gas is reliably exhausted, the processing time of exhaust processing is shortened. In addition, a sufficient supply amount of argon gas used for the exhaust treatment can be secured.

  (3) Even if any one of the argon gas supply unit connected to the tungsten hexafluoride gas pipe and the argon gas supply unit connected to the monosilane gas pipe fails, the normal argon gas supply unit may Gas can be supplied. Therefore, a highly reliable manufacturing apparatus and a highly reliable semiconductor device manufacturing apparatus can be provided.

  (4) During the monosilane gas supply process, monosilane gas and inert gas are supplied into the vacuum chamber. At this time, when the tungsten hexafluoride gas pipe is not used, the monosilane gas may flow backward into the tungsten hexafluoride gas pipe. Therefore, the backflowed monosilane gas reacts with the tungsten hexafluoride gas remaining in the tungsten hexafluoride gas pipe, and the reaction product may be adsorbed in the tungsten hexafluoride gas pipe. As a result, during the film forming process, the reaction product is supplied into the vacuum chamber 21 together with the tungsten hexafluoride gas from the pipe for tungsten hexafluoride gas, and the reaction product adheres on the insulating film of the substrate S, so that the semiconductor There is a risk of reducing the yield of the apparatus.

  In that respect, according to the present invention, during the monosilane gas supply process, the monosilane gas is supplied from the monosilane gas pipe, and at the same time, the argon gas is supplied from the tungsten hexafluoride pipe. Thereby, the backflow of monosilane gas to the pipe for tungsten hexafluoride gas can be suppressed. Therefore, the reaction between the tungsten hexafluoride gas and the monosilane gas can be avoided, and a reduction in the yield of the semiconductor device due to the reaction product can be suppressed.

(5) During the film formation process, tungsten hexafluoride is reduced by monosilane to form a thin film made of tungsten. However, the reaction product of tungsten hexafluoride gas and monosilane gas is represented by the chemical formula of SiH _x F _y such as trifluorosilane (SiHF ₃ ) and hexafluorosilicic acid (SiH ₂ F ₆ ) in addition to tungsten. Also included. Such a compound may adhere to the monosilane gas pipe, the tungsten hexafluoride gas pipe, and the inner wall of the vacuum chamber 21, and may be detached from the pipe and the inner wall of the vacuum chamber 21 during the film forming process. Then, the desorbed substance adheres to a portion where the tungsten thin film is not formed, such as on the insulating film of the substrate S, and there is a possibility that the tungsten thin film is formed by a reduction reaction with tungsten hexafluoride.

In that respect, according to the present invention, the temperature of the tungsten hexafluoride gas pipe, the monosilane gas pipe, the cleaning gas pipe, and the temperature of the inner wall of the vacuum chamber 21 are maintained at 80 ° C., resulting in a low temperature. SiH _x F _y is a reaction product of a tungsten hexafluoride gas and monosilane gas and can be prevented from adhering to the inner wall of the respective pipes and the vacuum chamber. Further, it is also prevented that the thermal decomposition products of SiH _x F _y due to temperature is high is generated. In addition, the temperature of the inner wall of the pipe and the vacuum chamber 21 is set to a range of 60 ° C. or more and 150 ° C. or less, and preferably about 80 ° C.

Each of the above embodiments may be modified as follows.
The cleaning process may be executed every time one substrate S is formed.
As the cleaning gas, silicon hexafluoride (SiF ₆ ), nitrogen trifluoride (NF ₃ ) gas, and chlorine trifluoride (ClF ₃ ) may be used in addition to the fluorine gas.

-In addition to argon gas, nitrogen (N ₂ ) gas or helium (He) gas may be used as the inert gas supplied into the vacuum chamber 21 during the exhaust treatment and the inert gas supplied simultaneously with the cleaning gas. Good.

The temperatures of the various pipes and the inner walls of the film forming chambers 13a and 13b may be maintained at 60 ° C. or higher and 150 ° C. or lower during the film forming process, the monosilane gas supply process, and the exhaust process.
・ At the time of exhaust treatment, argon gas was supplied from the argon gas pipe connected to the tungsten hexafluoride gas pipe and the argon gas pipe connected to the monosilane gas pipe. Even if argon gas is supplied only from the argon gas pipe, the effect (1) can be obtained.

  ・ Although it was equipped with an inert gas pipe connected to the tungsten hexafluoride gas pipe and an inert gas pipe connected to the monosilane gas pipe, it was not connected to the tungsten hexafluoride gas pipe. You may provide only the piping for active gas. Even in this case, the effects (1) to (5) can be obtained.

  The semiconductor device manufacturing apparatus has two loading / unloading ports 11a and 11b, two pretreatment chambers 12a and 12b, and two film formation chambers 13a and 13b. One membrane chamber may be provided. In addition, the number of various chambers and loading / unloading ports may be arbitrarily set.

  The semiconductor device manufacturing apparatus includes a pretreatment chamber, a heat treatment chamber, and a transfer chamber in addition to the film formation chamber, but may include only a loading / unloading port and a film formation chamber. A loading / unloading port may be provided. Even in this case, the effects (1) to (5) can be obtained.

Claims (8)

A film forming process is performed in which tungsten hexafluoride gas and monosilane gas are supplied to a vacuum chamber containing the substrate, and a thin film made of tungsten is selectively formed on a portion having higher conductivity than other portions of the substrate. In the semiconductor device manufacturing method to be executed,
Before the film formation process, the monosilane gas is supplied into the vacuum chamber to adsorb the monosilane gas to the highly conductive portion, and then the excess monosilane is exhausted from the vacuum chamber and the film formation process is performed. When performing the above, the tungsten hexafluoride gas and the monosilane gas are supplied to the vacuum chamber so that the partial pressure of the tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of the monosilane gas. A method for manufacturing a semiconductor device. In the monosilane gas supply process to the vacuum chamber performed before the film formation process, both the tungsten hexafluoride gas supply path and the monosilane gas supply path are used when the monosilane gas is exhausted from the vacuum chamber. 2. The method of manufacturing a semiconductor device according to claim 1, wherein an inert gas is supplied to the vacuum chamber. In the monosilane gas supply process to the vacuum chamber performed before the film forming process, the monosilane gas is supplied from the monosilane gas supply path, and the inert gas is supplied from the tungsten hexafluoride gas supply path. The method for manufacturing a semiconductor device according to claim 1, wherein: The temperature of the piping which supplies the said tungsten hexafluoride gas and the said monosilane gas, and the inner wall of the said vacuum chamber is maintained at 60 degreeC or more and 150 degrees C or less. The manufacturing method of the semiconductor device as described in any one of. A vacuum chamber capable of accommodating a substrate;
A first gas supply unit for supplying tungsten hexafluoride gas to the vacuum chamber;
A second gas supply unit for supplying monosilane gas to the vacuum chamber,
The tungsten hexafluoride gas and the monosilane gas are supplied to the vacuum chamber in which the substrate is accommodated, and a thin film made of tungsten is selectively formed on a portion having higher conductivity than other portions of the substrate. In a semiconductor device manufacturing apparatus that performs film processing,
Before the film formation process, the monosilane gas is supplied into the vacuum chamber to adsorb the monosilane gas to the highly conductive portion, and then the excess monosilane is exhausted from the vacuum chamber and the film formation process is performed. The tungsten hexafluoride gas and the monosilane gas are supplied to the vacuum chamber so that the partial pressure of the tungsten hexafluoride gas in the vacuum chamber exceeds the partial pressure of the monosilane gas. A semiconductor device manufacturing apparatus. The first gas supply unit includes:
A tungsten hexafluoride gas supply unit;
A first inert gas supply unit that supplies an inert gas to the vacuum chamber through the tungsten hexafluoride gas supply path;
The second gas supply unit includes:
A monosilane gas supply unit;
A second inert gas supply unit that supplies an inert gas to the vacuum chamber through the monosilane gas supply path;
In the monosilane gas supply process to the vacuum chamber performed before the film forming process, the first inert gas supply unit and the second inert gas are discharged when the monosilane gas is exhausted from the vacuum chamber. 6. The semiconductor device manufacturing apparatus according to claim 5, wherein an inert gas is supplied from both of the supply units to the vacuum chamber. In the monosilane gas supply process to the vacuum chamber, which is performed before the film formation process, when the monosilane gas is supplied to the vacuum chamber, the monosilane gas is supplied from the monosilane gas supply unit of the second gas supply unit. The semiconductor device manufacturing apparatus according to claim 6, wherein an inert gas is supplied from the first inert gas supply unit. The semiconductor device manufacturing apparatus according to any one of claims 5 to 7, further comprising pipes provided in the first gas supply unit and the second gas supply unit, and each temperature of an inner wall of the vacuum chamber. Is provided with a temperature control mechanism for maintaining the temperature at 60 ° C. or higher and 150 ° C. or lower.

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