JPWO2011016512A1 - Semiconductor device manufacturing method and semiconductor device manufacturing apparatus - Google Patents

Abstract

Prior to the film formation process in which a thin film made of tungsten is selectively formed on the conductive layer exposed from the via hole (33) provided in the insulating layer (32), a pretreatment for etching the surface of the conductive layer is performed. The When this conductive layer is made of any one of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride, an etching gas made of hydrogen gas and nitrogen gas is used. Further, when the conductive layer is made of any one of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide, fluorine gas and argon gas An etching gas consisting of

Description

  The present invention relates to a semiconductor device manufacturing method and a semiconductor device manufacturing apparatus. The present invention particularly relates to a method of manufacturing a semiconductor device using a selective chemical vapor deposition method (selective CVD method), which is a technique for selectively forming a tungsten film only in a desired region on the semiconductor device, and the semiconductor. The present invention relates to a device manufacturing apparatus.

  The semiconductor device includes a substrate made of a semiconductor material such as silicon. In a semiconductor device, a plurality of components such as active elements and passive elements are stacked on a substrate so as to be sandwiched between insulating films. In order to electrically connect these constituent elements to each other, a large number of through holes are formed in the insulating film so as to surround the constituent elements. Specifically, a contact hole for electrically connecting the active element and the multilayer wiring is formed between the active element such as a transistor or a memory cell provided on the substrate and the multilayer wiring stacked on the substrate. ing. In addition, via holes for electrically connecting the wirings are formed in the insulating layer between the wirings in the multilayer wiring structure. In the via hole, aluminum (Al) is often embedded in a DRAM that is required to be manufactured at low cost. Further, in a device that requires high-speed performance such as logic operation, copper (Cu) is often embedded in a via hole. The embedded metal material functions as a wiring for achieving an electrical connection between the active element and the wiring or between the wirings in the multilayer wiring structure. Generally, tungsten is used as a buried wiring material because it has high stability to heat.

  A blanket CVD method has been widely used as a method for forming such wiring. In this blanket CVD method, a titanium nitride (TiN) film is formed as a glue layer for growing a wiring material on the entire surface of the insulating layer in which the contact hole or via hole is formed, and the entire glue layer is formed. The method includes a step of forming a thin film made of a wiring material such as tungsten on the surface, and a step of removing the wiring material at unnecessary portions. 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 on the periphery of the opening of the contact hole and the via hole. This causes a so-called overhang in which the opening area of each hole is narrowed. Since the amount of tungsten that can enter these holes is limited due to the occurrence of overhang, the filling of the holes may be insufficient. The hole embedding defect becomes conspicuous as the hole diameter becomes smaller, particularly when the hole diameter is 40 nm or less. In addition, in the blanket CVD method, a step of removing the wiring material after film formation is essential, and the number of manufacturing steps of the semiconductor device increases accordingly. In addition, the cost for manufacturing the semiconductor device is increased by the amount of the removed material.

  Therefore, in recent years, the selective CVD method has been implemented (for example, Patent Document 1). The selective CVD method is a technique in which a thin film is formed only at a site where a thin film made of a wiring material is necessary, such as the contact hole or via hole. The part is a part having higher conductivity than other parts. According to this selective CVD method, it is possible to achieve both reduction in man-hours for manufacturing a semiconductor device and reduction in costs for the manufacturing.

Japanese Patent Laid-Open No. 10-229054

  The substrate that is the target of film formation by the selective CVD method is transferred to an apparatus for forming holes. Then, the substrate on which the contact hole or via hole is formed is transferred from the apparatus for forming the hole to the apparatus for performing the film forming process. During such transport, the substrate in vacuum is once transported to the atmosphere, so that the surface of the substrate is exposed to various oxidizing sources in the air. Therefore, the conductor surface that is the bottom surface of the hole is exposed to the atmosphere. The conductor surface is oxidized by an oxidizing source in the atmosphere, and an insulating oxide grows on the bottom surface of the hole. As a result, the conductivity of the conductor surface is impaired. In addition, as described above, the selective CVD method is a technique in which a thin film is selectively formed in a portion having higher conductivity than other portions in the substrate to be subjected to film formation processing. Therefore, when selective film formation was attempted using the selective CVD method having such characteristics with respect to the bottom surface of the hole thus losing conductivity, sufficient selective growth was realized on the bottom surface of the hole. It is hard to be done.

  As a method for removing the oxide itself formed on the conductor surface, a method of immersing the conductor surface in a chemical solution such as hydrofluoric acid (HF) is known. However, in this type of method in which the conductor surface is simply immersed in hydrofluoric acid, the oxide formed on the conductor surface is removed, and at the same time, the substrate or another conductor film formed on the same substrate is subjected to moisture in the chemical solution. There is a risk of corrosion due to the reaction.

  An object of the present invention is to provide a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method capable of forming a thin film only in a desired region with good selectivity when forming a tungsten thin film by a selective CVD method. is there.

In one embodiment of the present invention, a method for manufacturing a semiconductor device is provided. In the manufacturing method, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. A film forming process for selectively forming a thin film made of tungsten on the conductive layer; and prior to the film forming process, a pretreatment is performed on the surface of the conductive layer as the bottom of the through hole. A process of applying. The conductive layer is any one metal nitride selected from the group consisting of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride. In another aspect of the present invention, the step of performing the pretreatment includes a step of etching the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of hydrogen gas and nitrogen gas. A manufacturing method is provided. In the manufacturing method, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. A film forming process for selectively forming a thin film made of tungsten on the conductive layer; and prior to the film forming process, a pretreatment is performed on the surface of the conductive layer as the bottom of the through hole. A process of applying. The conductive layer is any one metal selected from the group consisting of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide. The step of performing the pretreatment includes a step of etching the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of fluorine gas and argon gas.

  In still another aspect of the present invention, a semiconductor device manufacturing apparatus is provided. The manufacturing apparatus is exposed through the through hole by exposing the substrate covered with the insulating film to the tungsten hexafluoride gas and the monosilane gas in such a manner that the conductive layer is exposed from the through hole provided in the insulating film. A film forming unit that selectively forms a thin film made of tungsten on the conductive layer, and a pretreatment is performed on the surface of the conductive layer as the bottom of the through hole before the film forming unit performs a film forming process. And a pre-processing unit to be applied. The conductive layer is any one metal nitride selected from the group consisting of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride. The pretreatment unit etches the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of hydrogen gas and nitrogen gas.

  In still another aspect of the present invention, a semiconductor device manufacturing apparatus is provided. The manufacturing apparatus is exposed through the through hole by exposing the substrate covered with the insulating film to the tungsten hexafluoride gas and the monosilane gas in such a manner that the conductive layer is exposed from the through hole provided in the insulating film. A film forming section for selectively forming a thin film made of tungsten on the conductive layer; and a pretreatment on the surface of the conductive layer as a bottom of the through hole before the film forming section performs a film forming process. And a pre-processing unit for applying. The conductive layer is any one metal selected from the group consisting of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide. The pretreatment unit etches the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of fluorine gas and argon gas.

The top view which shows the manufacturing apparatus of the semiconductor device which concerns on one embodiment of this invention. FIG. 2 is a partial cross-sectional view showing a film forming chamber provided in the manufacturing apparatus of FIG. 1. (A)-(f) is a schematic diagram which shows a part of manufacturing process of the semiconductor device manufactured using the manufacturing apparatus.

[First Embodiment]
A semiconductor device manufacturing method and a semiconductor device manufacturing apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

First, the outline of the semiconductor device manufacturing method and the manufacturing apparatus according to the present embodiment will be described with reference to FIG.
FIG. 1 shows an entire manufacturing apparatus for forming a thin film of tungsten as a wiring material only in a predetermined region on a substrate in a semiconductor device. As shown in FIG. 1, a semiconductor device manufacturing apparatus includes a transfer chamber 15 as a vacuum transfer chamber, a pair of loading / unloading ports 11a and 11b, a pair of pretreatment chambers 12a and 12b as a pretreatment unit, A pair of film forming chambers 13a and 13b as a film part and a heat treatment chamber 14 are provided. The transfer chamber 15 is disposed in the center of the manufacturing apparatus. The pair of loading / unloading ports 11a and 11b, the pair of pretreatment chambers 12a and 12b, the pair of film forming chambers 13a and 13b, and the heat treatment chamber 14 are arranged in an annular shape around the transfer chamber 15, and are viewed from below in FIG. It arranges in order toward the upper part.

  The loading / unloading ports 11a and 11b are provided adjacent to each other, and a substrate used for the tungsten thin film forming process is introduced into the manufacturing apparatus, or the substrate subjected to the tungsten thin film forming process is taken out from the manufacturing apparatus. Used for. Pre-processing chambers 12a and 12b as pre-processing units are provided adjacent to the loading / unloading ports 11a and 11b, respectively, and clean the substrate surface as a process before forming a tungsten thin film on the substrate.

  Each of the pretreatment chambers 12a and 12b includes a gas supply unit (not shown) that supplies an etching gas into the chamber and a plasma generation source (not shown) that generates plasma in the chamber using the etching gas. Each of the pretreatment chambers 12a and 12b drives the gas supply unit so that the gas type of the etching gas used for the etching performed when cleaning the substrate surface is switched according to the base of the tungsten thin film. The pretreatment chambers 12a and 12b drive the plasma generation source in a state where such an etching gas is supplied. Each of the pretreatment chambers 12a and 12b generates a plasma corresponding to the tungsten thin film base in the chamber to perform the above-described cleaning on the tungsten thin film base. As the plasma generation source, various plasma sources can be used as long as they are plasma sources that convert the etching gas into plasma, such as capacitively coupled plasma sources, inductively coupled plasma sources, and microwave plasma sources.

  The film forming chambers 13a and 13b are provided adjacent to the preprocessing chambers 12a and 12b, respectively, and execute a film forming process for forming the tungsten thin film on the substrate. The heat treatment chamber 14 is provided between the film forming chambers 13a and 13b, and executes a process of applying predetermined heat to the substrate on which the pretreatment has been completed.

  The transfer chamber 15 functions as a passage when the substrate moves between the two loading / unloading ports 11a and 11b and the five chambers 12a, 12b, 13a, 13b, and 14.

  When a semiconductor device is manufactured using the manufacturing apparatus configured as described above, first, a substrate to be subjected to a film forming process is introduced into the manufacturing apparatus through the loading / unloading ports 11a and 11b. This substrate includes, for example, a substrate in which a contact hole for forming a wiring is provided in an insulating film provided on a surface on which an active element is formed, or a substrate in which a via hole constituting a multilayer wiring is provided. As described above, the substrate has a portion with high conductivity (the bottom of the contact hole or via hole) and a portion with low conductivity (insulating film) on the surface. Since these two loading / unloading ports 11a and 11b have the same function with respect to the introduced substrate, a case where a substrate is introduced from the loading / unloading port 11a will be described below.

  The substrate introduced into the carry-in / carry-out port 11a is first transported to the pretreatment chamber 12a via the transfer chamber 15. As an example of the pre-processing performed in the pre-processing chamber 12a, the silicide layer corresponding to the bottom of the contact hole provided in the insulating layer or the wiring layer as the bottom of the via hole reacts with oxygen in the atmosphere. The process which removes the formed oxide layer is mentioned. The substrate that has been pretreated in the pretreatment chamber 12a is transferred again 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 substrate to which the thin film is connected, heat treatment is performed on the substrate exposed by the pretreatment performed by the pretreatment chamber 12a. When the heat treatment is completed, the heat-treated substrate is transferred again to the film forming chamber 13a through the transfer chamber 15. In the film forming process executed in the film forming chamber 13a, the tungsten thin film is selectively formed on the contact hole or via hole provided on the substrate, that is, on a portion having higher conductivity than other portions on the substrate. A CVD method is used. When the film forming process is completed, the substrate is transferred to the loading / unloading port 11a through the transfer chamber 15, and is carried out of the semiconductor device manufacturing apparatus from the loading / unloading port 11a.

  The substrate carried into the semiconductor device manufacturing apparatus from the carry-in / carry-out port 11b is the same as the substrate carried from the carry-in / carry-out port 11a, and the pretreatment in the pretreatment chamber 12b, the heat treatment in the heat treatment chamber 14, and the growth process. After the film forming process in the film chamber 13b is sequentially performed, the film is unloaded from the loading / unloading port 11b. During this time, when moving between the carry-in / carry-out port 11b and the various chambers 12b, 13b, 14, this is also carried through the transfer chamber 15 in the same manner as the substrate carried out from the carry-in / carry-out port 11a. That is, in the semiconductor device manufacturing apparatus, when the substrate carried into the device is transferred to each of the pretreatment chambers 12a and 12b, the heat treatment chamber 14, and the film formation chambers 13a and 13b, the substrate is always transferred. It is configured to pass through the transfer chamber 15. Therefore, the substrate once loaded into the semiconductor device manufacturing apparatus is not exposed to the atmosphere until it is unloaded from the apparatus.

  Next, the configuration of the film forming chambers 13a and 13b included in the semiconductor device manufacturing apparatus and the details of the film forming process executed in each of the film forming chambers 13a and 13b will be described with reference to FIG.

FIG. 2 shows a partial cross-sectional structure of each of the film forming chambers 13a and 13b. As shown in FIG. 2, each of the film forming chambers 13a and 13b includes a vacuum chamber 21, and a substrate stage 22 on which a substrate S to be subjected to a film forming process is placed. Is provided. The vacuum chamber 21 is provided with a source gas port P1 which is a supply port for tungsten hexafluoride (WF ₆ ) gas and monosilane (SiH ₄ ) gas which are source gases supplied to the vacuum chamber 21 during the film forming process. ing. In the vacuum chamber 21, a shower head 23 for uniformly diffusing the gas supplied from the source gas port P 1 into the vacuum chamber 21 is provided below and spaced from the source gas port P 1.

  A common pipe 40 is connected to the upper side of the source gas port P1. The common pipe 40 is a pipe where a first pipe 41 that introduces monosilane gas into the vacuum chamber 21 and a third pipe 43 that introduces tungsten hexafluoride gas into the vacuum chamber 21 merge. The first and third pipes 41 and 43 are provided with flow control units MFC1 and MFC3 for adjusting the flow rate of the gas flowing through each of the first and third pipes 41 and 43. The flow rate control units MFC1 and MFC3 execute the flow rate control, thereby realizing a desired gas supply in accordance with various processes related to the film forming process and the cleaning treatment. Incidentally, the cleaning process here refers to a process of removing the inner wall of the vacuum chamber 21 and the members in the vacuum chamber 21 by the film formation process, for example, a tungsten thin film attached to the substrate stage 22 with a fluorine gas as a cleaning gas. It is.

  In the middle of the first pipe 41 described above, a second pipe 42 for introducing argon (Ar) gas, which is an inert gas, into the first pipe 41 is connected so as to branch from the downstream side of the flow rate control unit MFC1. Has been. Further, in the middle of the third pipe 43 described above, this is also connected so that the fourth pipe 44 for introducing the argon gas, which is an inert gas, into the third pipe 43 branches from the downstream side of the flow rate control unit MFC3. Has been. The second pipe 42 and the fourth pipe 44 are provided with flow rate control units MFC2 and MFC4 that regulate the flow rate of the argon gas flowing therethrough. And when these flow control parts MFC2 and MFC4 perform flow control, an inert gas is introduced into the vacuum chamber 21 through corresponding piping according to various processes related to the film forming process and the cleaning process.

Further, a high frequency power supply 24 is electrically connected to the substrate stage 22. The high-frequency power source 24 applies a high-frequency electric field in the vacuum chamber 21 that causes the gas introduced through the various flow rate control units MFC1, MFC2, MFC3, and MFC4 to be converted into plasma. Further, the vacuum chamber 21 is provided with a cleaning gas port P2 for introducing a cleaning gas during a cleaning process that is alternately and repeatedly performed with the film forming process using the source gas. The cleaning gas port P2 is provided with a flow rate control unit MFC5 and connected to a fifth pipe 45 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. Has been.

  In addition, a turbo pump 25 is connected to the vacuum chamber 21 via an exhaust port P3. By driving the turbo pump 25, pressures corresponding to various processes of the film forming process or the cleaning process are formed in the vacuum chamber 21. Note that the temperature of the inner wall of the vacuum chamber 21, the piping 40 to 45, and the substrate S is set to a predetermined value for the vacuum chamber 21, the piping 40 to 45 through which the various gases flow, and the substrate stage 22 on which the substrate S is placed. A temperature control mechanism (not shown) for maintaining the temperature is provided.

As described above, the substrate S is loaded into the semiconductor device manufacturing apparatus from the loading / unloading ports 11a and 11b (FIG. 1), and then subjected to film formation in the pretreatment chambers 12a and 12b (FIG. 1). Pre-processing is performed. The substrate S is subjected to heat treatment in the heat treatment chamber 14 (FIG. 1), and then carried into the film forming chambers 13a and 13b. The substrate S is placed on the substrate stage 22 in the film forming chambers 13a and 13b, and is heated to a predetermined temperature by a temperature control mechanism provided on the substrate stage 22. Thereafter, film formation by selective CVD is performed. That is, tungsten hexafluoride gas and monosilane gas whose flow rates are controlled by the flow rate control units MFC1 and MFC2, respectively, are uniformly diffused from the shower head 23 to the vacuum chamber 21. A reduction reaction of tungsten hexafluoride by monosilane exemplified by the following reaction formula proceeds on a relatively highly conductive portion on the substrate S.
・ 2WF ₆ + 3SiH ₄ → 2W + 3SiF ₄ + 3H ₂
Or
WF ₆ + 2SiH ₄ → W + 2SiHF ₃ + 3H ₂
Note that the portion having relatively high conductivity in the substrate S differs depending on the manufacturing process in which the selective CVD method is used. For example, when the selective CVD method described above is used in a contact wiring formation process, the surface of the substrate to be formed is covered with an insulating film having a contact hole. A silicide layer covering an impurity diffusion region such as a MOS transistor formed on the surface of the substrate as an active element is exposed from the contact hole. When film formation by the selective CVD method is performed on a film formation target having such a configuration, the silicide layer as the bottom of the contact hole corresponds to a highly conductive portion of the substrate S. A tungsten thin film is selectively formed at this portion. In addition, when the selective CVD method described above is used in a via wiring formation process, the substrate surface to be formed is covered with an insulating film having via holes. A part of the lower layer wiring is exposed from this via hole. When the film formation process by the selective CVD method is performed on the film formation target having such a configuration, the wiring as the bottom of the via hole corresponds to a highly conductive part in the substrate S, and a tungsten thin film is formed in this part. The Rukoto.

As described above, when such a film forming process is executed a plurality of times, that is, when a film forming process is executed for a plurality of substrates S, a cleaning process using a cleaning gas is executed. That is, fluorine gas as a cleaning gas and argon gas as an inert gas are supplied from the fifth pipe 45 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 from this state. At this time, the tungsten thin film attached to the member such as the inner wall of the vacuum chamber 21 reacts with the plasma using fluorine gas, whereby fluoride, for example, tungsten hexafluoride, trifluorosilane (SiHF ₃ ), tetrafluorosilane ( SiF ₄ ), hydrogen fluoride (HF), or the like is generated. These fluorides are removed from the vacuum chamber 21 by the argon gas supplied simultaneously with the fluorine gas.

  By the way, the substrate S to be subjected to the film formation process by the selective CVD method is transported to a manufacturing apparatus that performs a hole formation process. Contact holes or via holes are formed in the substrate S in the manufacturing apparatus. Then, the substrate S is transferred from the manufacturing apparatus that performs the hole forming process to the manufacturing apparatus that performs the film forming process. A tungsten thin film is formed in the contact hole or the via hole by the film forming process. The substrate S thus transported is once carried out into the atmosphere when being transported between manufacturing apparatuses maintained in a vacuum atmosphere. For this reason, the surface of the substrate S is exposed to an oxidizing source such as oxygen or water existing in the atmosphere. Therefore, the surface of the conductive layer exposed through the contact hole or via hole is oxidized by the oxidation source. The conductive layer includes a silicide layer that constitutes an electrode of the active element or a metal layer that forms the base of the via wiring. The conductivity of the surface is impaired by the insulating oxide grown on the surface of the conductive layer. On the other hand, as described above, the selective CVD method used in the film forming process is a technique for selectively forming a thin film in a part where the conductivity is higher than other parts in the substrate to be processed. . Therefore, even if selective film formation is attempted using a selective CVD method having such characteristics for a conductive layer whose surface conductivity is impaired in this way, the selectivity of the film formation process is sufficiently secured. It becomes difficult to be done. As a result, the thin film grows at a site other than the desired site, and the selectivity cannot be avoided.

  Therefore, in the method and apparatus for manufacturing a semiconductor device according to this embodiment, the oxide grown on the surface of the conductive layer is removed by pre-processing that is performed prior to the film-forming process, so that the conductivity of the surface of the conductive layer is reduced. Sex is restored.

  Hereinafter, pre-processing executed in the pre-processing chambers 12a and 12b included in the semiconductor device according to the present embodiment will be described with reference to FIGS. 3 (a) to 3 (f). In the pretreatment, the material constituting the conductive layer exposed through the via hole was selected from the group consisting of titanium nitride (TiN), tantalum nitride (TaN), vanadium nitride (VN), and tungsten nitride (WN). This is a process executed when any one of them. Further, the contact hole or via hole forming process and the film forming process, which are processes before and after the pre-process, will be described with reference to FIGS. 3A to 3F.

  As shown in FIG. 3A, the base material 31 used in the via hole forming process is a silicon substrate having a base wiring on its surface. A conductive layer is formed on the surface of the underlying wiring. The conductive layer is a metal nitride made of any one selected from the group consisting of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride. In the via hole forming process, first, an insulating layer 32 made of, for example, a silicon oxide film or a silicon nitride film is laminated on the surface of the base material 31, thereby laminating the conductive layer and the insulating layer 32 in order. A substrate S having a structure is formed.

  Such a substrate S is carried into a semiconductor device manufacturing apparatus that executes a process of forming a through hole in the insulating layer 32 corresponding to the conductive layer of the substrate S. In the same apparatus, a process for forming a via hole 33 as a through hole is performed on the substrate S (FIG. 3B). Thereafter, the substrate S is unloaded from the manufacturing apparatus. Then, the substrate S is transported to the semiconductor device manufacturing apparatus according to the present embodiment and carried into the apparatus. The apparatus selectively forms a tungsten thin film in the via hole 33.

  At this time, since the substrate S is transported in the atmosphere, the conductive layer of the substrate S is exposed to the atmosphere through the via hole 33. That is, the surface of the conductive layer is exposed to various oxidation sources such as oxygen existing in the atmosphere. Therefore, an oxide layer 34 is formed on the surface of the conductive layer by growing an oxide which is a reaction product of such an oxidation source and a constituent element of the conductive layer (FIG. 3C). Then, the substrate S having the oxide layer 34 is loaded into the semiconductor device manufacturing apparatus according to the present embodiment via the loading / unloading ports 11 a and 11 b (FIG. 1), and then the transfer chamber 15. Are transferred to the pretreatment chambers 12a and 12b.

Next, in each of the pretreatment chambers 12a and 12b, hydrogen gas (H ₂ ) and nitrogen gas (N ₂ ) are selected as etching gases, and a plasma 35 using these etching gases is generated in the chambers 12a and 12b. . Then, when the above-described substrate S is exposed to such plasma 35, the oxide layer 34 grown on the conductive layer of the substrate S is removed (FIG. 3D). At this time, the plasma 35 made of hydrogen gas and nitrogen gas is applied to the surface of the underlying wiring made of the above-described constituent materials (TiN, TaN, VN, WN). Thereby, the chemical etching action by hydrogen gas is naturally performed, and the physical etching action by nitrogen gas is also performed. It is also possible to maintain the composition on the surface of the underlying wiring. Therefore, it is possible to effectively remove the oxide formed on the surface of the underlying wiring in such a manner that the corrosion of the conductive layer is suppressed and the electrical and chemical functional deterioration of the underlying wiring is suppressed. It becomes possible.

The conditions for the etching treatment as the pretreatment are set as follows. The flow rate of hydrogen gas ^{50~200sccm (84.5x10 -3 ~338x10 -3 Pa ·} m 3 / s), the flow rate of nitrogen gas is also ^{50~200sccm (84.5x10 -3 ~338x10 -3 Pa ·} m 3 / s) The ratio of the flow rate of hydrogen gas to the flow rate of nitrogen gas is 0.5-2, the pressure in the pretreatment chambers 12a, 12b is 0.5-100 Pa, and the temperature of the inner walls of the pretreatment chambers 12a, 12b Is set within a range of 70 to 120 ° C., a temperature of the substrate S of 150 to 400 ° C., and a high frequency power (power density) of 20 to 500 W / φ200 mm. This power density represents the power per unit area. In this case, it means that power of 20 to 500 W is supplied to the area of a circle having a diameter of 200 mm. These conditions are that the flow rates of hydrogen gas and nitrogen gas are both 100 sccm (169 × 10 ⁻³ Pa · m ³ / s), the pressure in the pretreatment chambers 12 a and 12 b is 1 Pa, and the temperature of the pretreatment chambers 12 a and 12 b is 80 Preferably, the temperature of the substrate S is set to 350 ° C., and the high frequency power (power density) is set to 50 W / φ200 m. Under this condition, the pretreatment is performed for about 15 to 60 seconds depending on the thickness of the oxide layer 34.

  The substrate S from which the oxide layer 34 grown on the surface of the conductive layer is removed is transferred to the heat treatment chamber 14 through the transfer chamber 15 (FIG. 1). The substrate S is subjected to heat treatment in the heat treatment chamber 14. Thereafter, the substrate S is again transferred to the film forming chambers 13a and 13b through the transfer chamber 15, and then a source gas 36 containing tungsten hexafluoride gas and monosilane gas is supplied to the substrate S (FIG. 3). (E)). Then, a tungsten thin film 37 is selectively formed on a portion of the substrate S having higher conductivity than other portions, that is, on the conductive layer exposed from the via hole 33 (FIG. 3F).

  As described above, in the present embodiment, the oxide layer 34 grown on the surface of the conductive layer of the substrate S is removed by the etching gas plasma 35 in the pretreatment which is a pretreatment process of the film forming treatment by the selective CVD method. . As a result, the conductivity of the surface of the conductive layer, which has been lost during the transfer between the semiconductor device manufacturing apparatuses, can be recovered, and as a result, the selectivity of the film formation process can be improved. Moreover, the temperature of the substrate S is maintained at 350 ° C. when the oxide layer 34 is removed by the plasma 35 of the etching gas. For this reason, the reaction product by such an etching process can be vaporized and the etching rate can be secured, and naturally the surface of the conductive layer can be kept clean and free from contamination by the reaction product. In addition, the temperature of the inner walls of the pretreatment chambers 12a and 12b is maintained at 80 ° C. during the execution of such pretreatment. For this reason, it can suppress that the said reaction product adheres to the inner wall of pre-processing chamber 12a, 12b. For this reason, these residual products are peeled off from the inner walls of the pretreatment chambers 12a and 12b for some reason and adhere to the cleaned conductive layer, and the electrical impedance in the pretreatment chambers 12a and 12b changes. The occurrence of poor impedance matching can be suppressed.

As described above, according to the method and apparatus for manufacturing a semiconductor device according to the present embodiment, the following effects can be obtained.
(1) In the substrate S, a conductive layer made of any one of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride is exposed from the via hole 33 provided in the insulating film. Prior to the film forming process, a pre-process for etching the surface of the conductive layer is performed on the substrate S by using an etching gas plasma 35 composed of hydrogen gas and nitrogen gas. As a result, the oxide layer 34 grown on the surface of the conductive layer can be removed, and the conductivity of the surface of the conductive layer can be recovered. Therefore, by performing a film formation process after such a pretreatment, a tungsten thin film can be selectively formed with respect to a conductive layer having higher conductivity than other portions of the substrate S. That is, the tungsten thin film can be formed only at a desired position with high selectivity.

  (2) The semiconductor device manufacturing apparatus includes a pair of film forming chambers 13a and 13b, a pair of pretreatment chambers 12a and 12b, a pair of film forming chambers 13a and 13b, and a transfer chamber 15. Each film forming chamber 13a, 13b performs a film forming process. Each pretreatment chamber 12a, 12b performs pretreatment. The film forming chambers 13a and 13b are connected to the film forming chambers 13a and 13b and the pretreatment chambers 12a and 12b. The transfer chamber 15 conveys the substrate S that has been pretreated in the pretreatment chambers 12a and 12b to the corresponding film formation chambers 13a and 13b. As a result, the substrate S pretreated in the pretreatment chambers 12a and 12b can be transferred to the film forming chambers 13a and 13b without being exposed to the atmosphere. That is, it is possible to avoid that the surface of the conductive layer from which the oxide film has been removed by the pretreatment is oxidized again before the film formation treatment.

  (3) The temperature of the substrate S is maintained at 350 ° C. during the pretreatment for etching the surface of the conductive layer. As a result, it is possible to vaporize a reaction product generated by the reaction between the oxide on the surface of the conductive layer and the plasma of the etching gas during the etching process. Therefore, it is possible to suppress the deposition of such reaction products on the surface of the conductive layer, and it is also possible to suppress the etching process speed from being reduced by the reaction product and the contamination of the etched conductive layer surface. It becomes.

(4) The temperature of the inner walls of the pretreatment chambers 12a and 12b is maintained at 80 ° C. Thereby, it can suppress that the said reaction product adheres to the inner wall of pre-processing chamber 12a, 12b, and can suppress the generation | occurrence | production defect of the high frequency electric field resulting from the contamination of the conductive layer surface and an impedance matching defect by extension. It becomes like this.
[Second Embodiment]
In the first embodiment, the conductive layer is formed of any one of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride.

Instead, in the second embodiment, the conductive layer is made of tungsten (W), titanium (Ti), tantalum (Ta), vanadium (V), titanium tungsten (TiW), nickel (Ni), cobalt. Any one selected from the group consisting of (Co), titanium silicide (TiSi _x ), tungsten silicide (WSi _x ), tantalum silicide (TaSi _x ), cobalt silicide (CoSi _x ), and nickel silicide (NiSi _x ). Formed from metal. The preprocessing executed in this case will be described below with reference to FIG. However, among the processes shown in FIG. 3, only the process shown in FIG. 3 (d) is specific to the present embodiment, so the process according to FIG. Only explained. The pretreatment in this embodiment can be applied not only to the via hole described in the first embodiment but also to a contact hole.

As shown in FIG. 3D, the substrate S on which the oxide layer 34 has grown on the surface of the conductive layer as described above is transferred to the pretreatment chambers 12a and 12b. In each of the pretreatment chambers 12a and 12b, fluorine (F ₂ ) gas and argon (Ar) gas are selected as etching gases, and plasma 35 using such etching gas is generated in the chambers 12a and 12b. . When the substrate S is exposed to the plasma 35, the oxide layer 34 grown on the conductive layer of the substrate S is removed. At this time, the plasma 35 made of fluorine gas and argon gas is applied to the surface of the underlying wiring made of the above-described constituent materials (W, Ti, TiW, Ta, V, NiCo, TiSi _x , WSi, TaSi, CoSi _x , NiSi _x ). Applies. Therefore, the chemical etching action by fluorine gas naturally enables the physical etching action by argon gas. Therefore, it is possible to effectively remove the oxide formed on the surface of the underlying wiring in such a manner that the corrosion of the conductive layer is suppressed and the electrical and chemical functional deterioration of the underlying wiring is suppressed. It becomes possible.

The conditions for the etching treatment as the pretreatment are set as follows. The fluorine gas content of the etching gas 35 is 5 to 20%, the flow rate of the etching gas is 50 to 200 sccm (84.5 × 10 ^{−3 to} 338 × 10 ⁻³ Pa · m ³ / s), and the pretreatment chambers 12 a and 12 b The pressure is 0.5 to 100 Pa, the temperature of the inner walls of the pretreatment chambers 12 a and 12 b is 70 to 120 ° C., the temperature of the substrate S is 150 to 400 ° C., and the high frequency power (power density) is 20 to 500 W / φ200 mm. It is set within the range. These conditions are that the fluorine gas content of the etching gas is 5%, the flow rate of the etching gas is 100 sccm (169 × 10 ⁻³ Pa · m ³ / s), the pressure in each of the pretreatment chambers 12a and 12b is 1 Pa, The temperatures of the processing chambers 12a and 12b are set to 80 ° C., the temperature of the substrate S is set to 350 ° C., and the high frequency power is set to 50 W / φ200 m. It is preferable that the pretreatment is performed for 20 seconds under these conditions. Note that the etching rate when a conductive layer made of tungsten, for example, is etched under such conditions is about 0.1 nm / sec, whereas the etching rate of the oxide layer 34 formed on this conductive layer is About 0.15 nm / sec. That is, the above conditions are also etching conditions in which etching on the oxide layer 34 is more likely to proceed than etching on the conductive layer.

  In the second embodiment described above, the effects according to (2) to (5) obtained by the first embodiment described above can be obtained, and the following effect can be obtained instead of the effect of (1). Can play.

(1 ′) In the substrate S, the conductive layer is exposed from through holes such as via holes 33 and contact holes provided in the insulating layer 32. The conductive layer is made of any one of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide. Prior to the film formation process, a pre-process for etching the surface of the conductive layer is performed on the substrate S by using an etching gas plasma 35 composed of fluorine gas and argon gas. As a result, the oxide layer 34 grown on the surface of the conductive layer can be removed, and the conductivity of the surface of the conductive layer can be recovered. Therefore, by performing a film formation process after such a pretreatment, a tungsten thin film can be selectively formed with respect to a conductive layer having higher conductivity than other portions of the substrate S. That is, the tungsten thin film can be formed only at a desired position with high selectivity.
[Other embodiments]
In addition, each said embodiment may be changed as follows.

  In each of the above embodiments, after performing the film forming process a plurality of times, that is, after performing the film forming process on the plurality of substrates S, cleaning for cleaning the film forming chambers 13a and 13b is performed. Processing is executed. However, the cleaning process may be executed every time the film forming process is executed, that is, every time the film forming process is executed on one substrate S.

In each of the above embodiments, fluorine gas is used as the cleaning gas. Not limited to this, silicon hexafluoride (SiF ₆ ), nitrogen trifluoride (NF ₃ ) gas, or chlorine trifluoride (ClF ₃ ) may be used as the cleaning gas.

  In each of the above embodiments, the temperature of the inner walls of the pretreatment chambers 12a and 12b is maintained at 70 to 120 ° C., particularly 80 ° C. during the pretreatment. However, the temperature of the inner walls of the pretreatment chambers 12a and 12b during the process may be 70 ° C. or less. Even in this case, it is possible to obtain the effect according to the item (1) or (1 ′), (2), (3).

  In each of the above embodiments, the temperature of the substrate S is maintained at 150 to 400 ° C., particularly 350 ° C., during the pretreatment. However, the temperature of the substrate during the processing may be 150 ° C. or lower. Even in this case, it is possible to obtain the effect according to the item (1) or (1 ′), (2), (4).

  The semiconductor device manufacturing apparatus according to the present embodiment has a configuration in which the pretreatment chambers 12a and 12b and the film formation chambers 13a and 13b are connected to a common transfer chamber 15 to form a common vacuum system. For example, the pretreatment chambers 12a and 12b and the film forming chambers 13a and 13b are different vacuum systems through an atmosphere made of an inert gas, and the semiconductor device manufacturing apparatus is transported between them. The substrate may be transported through the inert gas atmosphere. In other words, if the oxide film is difficult to grow on the surface of the conductive layer of the substrate when the substrate is transferred from the pretreatment chambers 12a and 12b to the film forming chambers 13a and 13b, the above item is determined by such a semiconductor device manufacturing apparatus. The effects according to (1) or (1 ′) and (2) to (5) can be obtained.

  The semiconductor device manufacturing apparatus according to the present embodiment is configured to include two loading / unloading ports 11a and 11b, two pretreatment chambers 12a and 12b, and two film formation chambers 13a and 13b. However, the number of loading / unloading ports, the pretreatment chamber, and the film forming chamber may be one each. In addition, the number of various chambers and loading / unloading ports constituting the semiconductor device manufacturing apparatus can be arbitrarily changed.

Claims (9)

On the conductive layer exposed through the through hole, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. Performing a film forming process for selectively forming a thin film made of tungsten on
Prior to the film forming process, a method of manufacturing a semiconductor device comprising a step of pre-processing the surface of the conductive layer as the bottom of the through hole,
The conductive layer is any one metal nitride selected from the group consisting of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride, and the step of performing the pretreatment includes etching comprising hydrogen gas and nitrogen gas A method for manufacturing a semiconductor device, comprising: exposing the substrate to plasma using a gas to etch a surface of the conductive layer. On the conductive layer exposed through the through hole, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. Performing a film forming process for selectively forming a thin film made of tungsten on
Prior to the film forming process, a method of manufacturing a semiconductor device comprising a step of pre-processing the surface of the conductive layer as the bottom of the through hole,
The conductive layer is any one metal selected from the group consisting of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide, The method of manufacturing a semiconductor device, wherein the pre-processing step includes a step of etching the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of fluorine gas and argon gas. The method for manufacturing a semiconductor device according to claim 1, wherein the step of performing the pretreatment includes a step of maintaining the temperature of the substrate at 150 ° C. or higher and 400 ° C. or lower. 4. The semiconductor device according to claim 1, wherein the step of performing the pretreatment includes a step of maintaining a temperature of a pretreatment chamber in which the substrate is accommodated at 70 ° C. or more and 120 ° C. or less. Production method. On the conductive layer exposed through the through hole, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. A film forming unit for selectively forming a thin film made of tungsten;
A semiconductor device manufacturing apparatus comprising: a pre-processing unit that performs pre-processing on a surface of the conductive layer as a bottom of the through hole before the film-forming unit performs a film forming process;
The conductive layer is any one metal nitride selected from the group consisting of titanium nitride, tantalum nitride, vanadium nitride, and tungsten nitride;
The semiconductor device manufacturing apparatus, wherein the pretreatment unit etches the surface of the conductive layer by exposing the substrate to plasma using an etching gas composed of hydrogen gas and nitrogen gas. On the conductive layer exposed through the through hole, the substrate covered with the insulating film is exposed to tungsten hexafluoride gas and monosilane gas so that the conductive layer is exposed from the through hole provided in the insulating film. A film forming unit for selectively forming a thin film made of tungsten;
A pre-processing unit that pre-processes the surface of the conductive layer as the bottom of the through hole before the film-forming unit performs a film-forming process;
A semiconductor device manufacturing apparatus comprising:
The conductive layer is any one metal selected from the group consisting of tungsten, titanium, tantalum, vanadium, titanium tungsten, nickel, cobalt, titanium silicide, tungsten silicide, tantalum silicide, cobalt silicide, and nickel silicide;
The apparatus for manufacturing a semiconductor device, wherein the pretreatment unit etches the surface of the conductive layer by exposing the substrate to plasma using an etching gas comprising fluorine gas and argon gas. The film formation unit has a first storage chamber that stores the substrate, and a film formation chamber that uses the tungsten hexafluoride gas and the monosilane gas therein.
The pretreatment unit has a second accommodation chamber that accommodates the substrate, and a pretreatment chamber that generates plasma using the etching gas therein.
A vacuum transfer chamber connected to the first storage chamber and the second storage chamber;
The apparatus for manufacturing a semiconductor device according to claim 5, wherein the vacuum transfer chamber transfers the substrate that has been subjected to the pretreatment in the pretreatment chamber to the film formation chamber. In the manufacturing apparatus of the semiconductor device as described in any one of Claims 5-7,
The said pre-processing part is further provided with the temperature control mechanism which maintains the temperature of the said board | substrate at 150 degreeC or more and 400 degrees C or less. The manufacturing apparatus of the semiconductor device characterized by the above-mentioned. In the manufacturing apparatus of the semiconductor device according to claim 7 or 8,
The semiconductor device manufacturing apparatus, wherein the pretreatment unit further includes a temperature adjustment mechanism that maintains the temperature of the inner wall of the pretreatment chamber at 70 ° C. or more and 120 ° C. or less.

Images