JP4473824B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a structure of a semiconductor device and a manufacturing method thereof, and more particularly to a wiring structure including a barrier metal of a copper film and a manufacturing method thereof.

  A copper (Cu) film having a low specific resistance is used for a multilayer wiring of a semiconductor integrated circuit (LSI), and a damascene wiring in which a Cu film is embedded in a groove or a via hole formed in an interlayer insulating film is mainly used. The wiring width becomes narrower with the miniaturization of the LSI, and the wiring thickness tends to become thinner for the purpose of reducing the inter-wiring capacitance. Therefore, in fine damascene wiring, the ratio of the barrier metal film having a high specific resistance to the wiring cross-sectional area greatly affects the wiring resistance. That is, the thinner the barrier metal film, the lower the resistance of the damascene wiring. However, the barrier metal film is required to simultaneously prevent diffusion of Cu atoms into the interlayer insulating film, adhere to the Cu film, and adhere to the interlayer insulating film.

  In particular, the adhesion between the barrier metal film and the Cu film is very important in the electromigration (EM) resistance and stress migration (SM) resistance of the wiring. Furthermore, it is desired that the barrier metal film be formed conformally with the thinnest film thickness satisfying the above requirements and with a uniform thickness on the bottom and side surfaces of the groove formed in the interlayer insulating film.

  Next, the current situation regarding the formation of a thin barrier metal film will be described. A general physical vapor deposition method (PVD method) has low step coverage. Therefore, it is difficult to form a conformal barrier metal film by the PVD method in a dual damascene structure in which grooves and via holes formed in an interlayer insulating film are filled with metal. For this reason, an ionized PVD method has been developed to improve the bottom coverage by attracting metal ions by the substrate bias and improve the side coverage by utilizing the resputtering effect of ions, and has been used for forming a barrier metal film. However, due to the miniaturization and high aspect ratio of wiring, conformal film formation sufficient to maintain wiring resistance, barrier properties, and adhesion will become increasingly difficult in the future. On the other hand, although a conformal barrier metal film can be formed by chemical vapor deposition (CVD), a high temperature process cannot be applied in the wiring process due to the problem of SM failure. For this reason, the CVD method has a problem that the source gas of the material to be deposited as a barrier metal film is decomposed at the allowable temperature in the wiring process. Further, an atomic layer growth method (ALD method) has been proposed in which atomic layers are stacked one by one on a substrate surface to grow a thin film as a conformal film forming method for an ultrathin film. Although the ALD method is not suitable for forming a thick film, an ultrathin film can be formed with good step coverage. As with the CVD method, the ALD method has a problem that it is difficult to thermally decompose the source gas within the allowable temperature of the wiring process, and the decomposition is promoted by plasma irradiation in the step of decomposing the adsorbed source gas to lower the temperature. Methods (for example, see Patent Document 1) and methods for promoting decomposition by UV light irradiation (for example, see Patent Documents 2 and 3) have been proposed.

In recent interlayer insulating films, low dielectric constant insulating films have been used to suppress signal delay. The low dielectric constant insulating film is not only an organic insulating film but also an inorganic insulating film, which contains a lot of carbon (C), has many vacancies, and traps oxidizing species such as water (H ₂ O). Yes. Therefore, in the CVD method and the ALD method in which the film formation temperature is lowered using plasma irradiation, carbon in the insulating film is released by plasma irradiation in the decomposition process of the source gas, and the insulating film is damaged. is there. In particular, in the case of plasma using a gas containing hydrogen (H) or oxygen (O), the low dielectric constant insulating film may be etched, and the insulating film may be peeled off.

  Furthermore, in the case of a low dielectric constant insulating film containing a large amount of oxidizing species, the barrier metal film can be formed during the formation of the barrier metal film even if an ALD method or a CVD method is used to lower the decomposition temperature by plasma irradiation or UV light irradiation. The film may be oxidized. The oxidized barrier metal film cannot suppress the transmission of oxidized species. As a result, the barrier metal film is entirely oxidized by the oxidizing species, and there is a problem that the adhesion between the barrier metal film and a wiring material such as a Cu film is lowered.

  The adhesion between the barrier metal film and the Cu film includes an adhesion determined as a material, and an adhesion that changes over time due to a change in the barrier metal film. In particular, the change in adhesion over time is extremely serious because it causes SM and EM defects during actual use as well as during the manufacturing process. In processing steps involving plasma irradiation, electron beam irradiation, ultraviolet irradiation, and insulating film curing processes, molecules containing carbon in the insulating film are released, the insulating film is damaged, and the debonded carbon is bonded to the site. Is easy to adsorb water.

  During this manufacturing process or during actual use, the barrier metal film may deteriorate over time due to the oxidation of the barrier metal film due to the oxidizing species contained in the insulating film, which may reduce the adhesion to the Cu film. . Further, the barrier metal film may be carbonized (carbideized) by molecules containing C contained in the insulating film.

As described above, it becomes increasingly difficult to suppress the deterioration of the barrier metal film and maintain the adhesion. In addition, a process for forming an oxide at the interface in advance (for example, see Patent Document 4) has been proposed. However, when an oxide is actively formed, an oxide having a large valence and a low density is formed. The desired form cannot be obtained.
JP 2003-297814 A JP 2001-220287 A JP 2002-170821 A JP 2000-269213 A

  The present invention provides a method for manufacturing a semiconductor device in which a metal film is formed with good adhesion to a wiring material, and a semiconductor device having a metal film with good adhesion to a wiring material.

According to one aspect of the present invention, (a) a step of releasing at a first substrate temperature so as to leave a part of oxidized species in an insulating film having a recess formed on the surface and the surface of the insulating film; B) A barrier metal film made of metal is formed on the insulating film at a second substrate temperature that is lower than the first substrate temperature and does not release oxidizing species from the insulating film in a continuous vacuum with the step of releasing the oxidizing species. And (c) a step of forming a Cu wiring metal film on the barrier metal film, and (d) an oxygen concentration of the barrier metal film due to the oxidized species remaining in the insulating film after the barrier metal film is formed . And (e) oxidizing the barrier metal film so that the insulating film side is high and the Cu wiring metal film side has a low concentration gradient, and (e) the barrier metal film is oxidized from the first substrate temperature. Semiconductor including the process of heating at high temperature A method for manufacturing a body device is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor device provided with the manufacturing method of the semiconductor device which can form a wiring structure with favorable adhesiveness with a wiring material, and the metal film with favorable adhesiveness with a wiring material can be provided.

  Next, first to sixth embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Also, the following first to sixth embodiments exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the component parts. The material, shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
In the method of manufacturing a semiconductor device according to the first embodiment of the present invention, an oxide is formed on the surface of the metal film in contact with the interface between the metal film and the insulating film using the gas released from the insulating film. Is the method.

  First, a manufacturing process of a semiconductor device will be described with reference to FIGS. In the following, a Cu film as a wiring material, a titanium (Ti) film as a barrier metal film, a polyarylene ether (hereinafter abbreviated as PAE) film, which is an organic low dielectric constant insulating film, and an inorganic low dielectric constant insulating film as an insulating film A case of forming a dual damascene multilayer wiring using a carbon-containing silicon oxide (hereinafter abbreviated as SiCO) film or the like will be described.

(A) Although not shown in the drawing, the first PAE film 22 is formed on the first silicon oxide (SiO ₂ ) film 21 from which the lower electrode electrically connected to the semiconductor element or the like in the semiconductor substrate 10 is exposed. Then, the second SiO ₂ film 23 is sequentially formed to obtain the structural cross-sectional view shown in FIG.

(B) Next, as shown in FIG. 2, the first PAE film 22 and the second SiO ₂ film 23 are selectively etched away by using a photolithography technique and a reactive ion etching (RIE) method. Thus, the first wiring groove 201 is formed. Next, a first Ti film 30 b is formed as a barrier metal film on the surface of the second SiO ₂ film 23, the side surface portion and the bottom portion of the first wiring groove 201. The first Ti film 30b is formed with a good step coverage, and the structural cross-sectional view shown in FIG. 3 is obtained.

  (C) As shown in FIG. 4, the first Cu seed film 41 is formed in a continuous vacuum. Next, a first Cu plating film 42 is formed so as to fill the first wiring groove 201 using a plating apparatus (FIG. 5). Next, a heat treatment step for increasing the particle size in advance is performed in order to prevent variations due to changes in film quality over time due to self-aging of the Cu film. Thereafter, the first Cu plating film 42 and the first Ti film 30b are planarized by using a chemical mechanical polishing (CMP) method, and the first Ti film 30b and the first Cu film as shown in FIG. A first wiring layer 40 made of the plating film 42 is formed.

(D) Next, as shown in FIG. 7, a silicon carbonitride (SiCN) film 51, a SiCO film 52, a second PAE film 53, and a third SiO ₂ film 54 are formed in sequence. Here, the SiCN film 51 is formed as a stopper film and a Cu diffusion preventing film in the process using the RIE method. The third SiO ₂ film 54 is formed as a protective film in a process using the CMP method. An interlayer insulating film 50 is formed by the SiCN film 51, the SiCO film 52, the second PAE film 53, and the third SiO ₂ film 54.

  (E) Next, the interlayer insulating film 50 is selectively removed by etching using the photolithography technique and the RIE method to form the second wiring trench 202 and the via hole 203. As a result, a part of the surface of the first wiring layer 40 is exposed as shown in FIG. Next, a second Ti film 30 c is formed as a barrier metal film on the surface of the interlayer insulating film 50. The second Ti film 30c is formed with good step coverage and obtains a structural cross-sectional view shown in FIG.

  (F) As shown in FIG. 10, a second Cu seed film 71 is formed in a continuous vacuum. Next, a second Cu plating film 72 is formed so as to fill the second wiring trench 202 and the via hole 203 using a plating apparatus (FIG. 11). Next, a heat treatment step for increasing the particle size in advance is performed in order to prevent variations due to changes in film quality over time due to self-aging of the Cu film. Thereafter, the second Cu plating film 72 and the second Ti film 30c are planarized using CMP, and the second Ti film 30c and the second Cu plating film 72 are formed as shown in FIG. Two wiring layers 70 are formed. Further, in order to form a multilayer wiring, the steps of FIGS. 7 to 12 may be repeated.

An example of the method for manufacturing the semiconductor device according to the first embodiment will be described below. Hereinafter, the case where the interlayer insulating film 50 shown in FIG. 7 and the second Ti film 30c shown in FIG. 9 are formed will be described as an example. As described in the description of FIG. 7, the SiCN film 51 as the stopper film on the first wiring layer 40, the SiCO film 52 and the second PAE film 53 as the interlayer insulating film, and the third film as the protective film in the process using the CMP method. The SiO ₂ film 54 or the like can be applied. Further, only the SiCO film 52 or only the second PAE film 53 may be formed as an interlayer insulating film. When a porous film having a high hygroscopic property is used for at least one insulating film among the interlayer insulating films composed of a plurality of kinds of insulating films, more oxidized species are released from the insulating film. A “porous film” is a film that contains a large number of pores in order to lower the dielectric constant. When a gas released from an insulating film is used to form an oxide on the surface of a metal film, It is extremely effective to use an insulating film containing an oxidizing species such as water and having a relative dielectric constant of 3 or less.

(A) As shown in FIG. 8, the interlayer insulating film 50 is selectively removed by etching using a photolithography technique and an RIE method to form the second wiring trench 202 and the via hole 203. Thereafter, heat treatment is performed in a vacuum or a reducing atmosphere such as H ₂ gas at a temperature of, for example, 250 ° C. or more and 300 ° C. or less. By this heat treatment, H ₂ O contained in the interlayer insulating film 50 or bonds are broken when the second wiring trench 202 and the via hole 203 are formed, and carbon-based residues and the like remaining in the interlayer insulating film 50 are removed. Is done. At this time, if it is performed in a reducing atmosphere, the oxide film on the surface of the first wiring layer 40 exposed at the bottom of the via hole 203 can be reduced.

  (B) Next, the substrate 10 is transported in a continuous vacuum, for example, into an ionization sputtering chamber shown in FIG. Then, the substrate 10 is placed on a susceptor that is set to at least the heating temperature in the degassing process step of the interlayer insulating film 50, preferably at room temperature or lower. The substrate 10 is adsorbed by the susceptor, and the temperature of the substrate 10 is maintained at a temperature equivalent to that of the susceptor.

(C) As described in FIG. 9, the second Ti film 30c is formed by a method such as ionization sputtering. Generally, when the second Ti film 30c film is formed using normal plasma, the temperature of the substrate 10 rises during the formation of the second Ti film 30c. Therefore, the temperature of the substrate 10 is controlled during the formation of the second Ti film 30c so as not to exceed the temperature in the degassing process or the H ₂ reduction heating process performed before the formation of the second Ti film 30c. For example, if the degassing process or the H ₂ reduction heat treatment is performed at 250 ° C., the temperature of the substrate 10 is controlled so as not to exceed 250 ° C., and if it is performed at 300 ° C., the temperature does not exceed 300 ° C. .

(D) Next, the substrate 10 is transported to a chamber for forming a Cu film in a continuous vacuum, and the substrate 10 is cooled to a room temperature or lower to form a second Cu seed film 71 as shown in FIG. The second Cu seed film 71 may be formed by a PVD method, a CVD method, an ALD method, or the like so as to have a desired film thickness, for example, about 60 nm. Next, the substrate 10 is exposed to the atmosphere, and the via hole 203 and the second wiring groove 202 are filled with the second Cu plating film 72 by plating as shown in FIG. Then, a heat treatment step (annealing after plating) for increasing the particle size is performed in advance in order to prevent variation due to the change in film quality with time due to self-aging of the second Cu plating film 72 and the like. Annealing after plating is performed under conditions such as a temperature of 150 ° C./hour 60 minutes to a temperature of 300 ° C./hour 60 minutes in either a vacuum, a nitrogen (N ₂ ) gas atmosphere, or an N ₂ / H ₂ gas atmosphere. . Needless to say, the annealing conditions change with the various plating conditions as well as the optimum temperature and time. Finally, the second Cu plating film 72 is planarized by CMP to form a dual damascene structure.

  Hereinafter, Ti oxidation during formation of the Ti film will be described. As already described, in order to lower the dielectric constant, the low dielectric constant insulating film has many vacancies. Therefore, when the substrate 10 is heated, oxidizing species such as water and oxygen contained in the vacancies of the insulating film are released from the grooves or the side surfaces of the via holes. As shown in FIG. 14A, when oxidized species are released in the process in which Ti atoms, which are sputtered particles, fly, Ti atoms combine with oxygen to form titanium oxide (TiOx). In that case, since Ti atoms are bonded to oxygen in a state where they are not bonded to other Ti atoms, the distance between Ti-O atoms is wide. This is because the Ti particles fly in atomic or molecular form and form an oxide in a form that is likely to cause a sufficient oxidation reaction, so an oxide that forms a stable bond and an oxide with a relatively large valence is formed. Because it can be done. The TiOx film formed on the surface of the insulating film 20 by repeating such a film forming process becomes a TiOx film having a wide Ti—O atomic interval and a low molecular density (FIG. 14B). Further, as shown in FIG. 14C, such a low molecular density TiOx film cannot suppress further release of the oxidized species remaining in the insulating film 20, and finally all Ti films have a molecular density. It will be formed as a low TiOx film. Such a TiOx film has low adhesion to the Cu film, and when Cu film is buried as a wiring material in a groove or a via hole, interfacial diffusion of Cu atoms occurs at the TiOx / Cu interface. That is, the SM resistance of the Cu wiring is low, and voids are generated in the wiring.

  On the other hand, when the Ti film is formed at a temperature lower than that in the degassing process, there is no release of oxidizing species from the insulating film 20 as shown in FIG. Therefore, as shown in FIG. 15B, a pure Ti film 30a not containing TiOx or the like is formed as a barrier metal film. Thereafter, in an insulating film forming process or a sintering process after the Ti film is formed, when heated to a temperature higher than that in the degassing process process, oxidized species remaining in the insulating film 20 are released and come into contact with the insulating film 20. The surface of the Ti film 30a is oxidized. However, since the Ti-Ti bond of the Ti film 30a is already formed, the oxidation of the Ti film 30a proceeds by diffusion and solid solution between Ti-Ti atoms. Therefore, a TiOx film having a dense molecular density is formed (FIG. 15C). The TiOx film having a high molecular density suppresses the release of oxidized species from the insulating film 20. Therefore, the oxidation of the Ti film 30a is limited to the region near the interface between the insulating film 20 and the Ti film 30a, and the Ti film in the region away from the interface can be suppressed from being oxidized. That is, according to the semiconductor manufacturing method according to the first embodiment, the metal film in contact with both the wiring metal film and the insulating film is compared with the atomic or molecular density of the metal in the portion where the metal film is in contact with the wiring metal film. Thus, it is possible to realize a semiconductor device in which the metal atom or molecular density of the portion where the metal film is in contact with the insulating film is higher and the metal density gradually changes. In the semiconductor device shown in FIGS. 1 to 12, in the second Ti film 30 c in contact with both the second Cu plating film 72 and the interlayer insulating film 50, the second Ti film 30 c is the second Cu plating. Compared with the Ti atom or molecular density of the portion in contact with the film 72, the Ti atom or molecular density of the portion of the second Ti film 30c in contact with the interlayer insulating film 50 is higher and the second Ti film 30c. The atomic density of Ti gradually changes.

  By defining the vertical relationship of the temperature of the degassing process and the barrier metal film forming process of the semiconductor device manufacturing method according to the first embodiment, at the time when the Cu film is embedded in the groove or via hole, The Ti film at the Ti / Cu interface is not oxidized. Then, in the step after forming the Ti / Cu interface that can ensure good adhesion, the oxidation of the barrier metal occurs with the difference in molecular density as described above. As a result, the Ti / Cu interface can maintain adhesion, and the SM resistance of the Cu film does not deteriorate. In addition, the TiOx film having a high molecular density is effective not only for suppressing the release of oxidizing species from the insulating film 20 but also for suppressing the diffusion of Cu into the insulating film 20. The method for manufacturing a semiconductor device according to the first embodiment of the present invention is extremely effective particularly for the insulating film 20 having a relative dielectric constant of 3 or less.

  The analysis results of the sample created by the semiconductor device manufacturing method according to the first embodiment are shown in FIGS. 16A to 16C show a sample manufactured by using the semiconductor manufacturing method according to the first embodiment of the present invention by the 2θ-θ method of the X-ray diffraction method, and a sample manufactured by the prior art. It is the result of comparative measurement. It should be noted that the stage temperatures in FIGS. 16B and 16C are stage holding temperatures when forming the Ti film, not the substrate temperature. The horizontal axis is 2θ at the time of measurement. The vertical axis represents intensity (Intensity), and the unit is cps (count per sec).

  From FIGS. 16A to 16C, the peak intensity of the TiOx film of the sample formed by the prior art is 2182 cps. On the other hand, the peak intensity of the sample TiOx film formed by the semiconductor manufacturing method according to the first embodiment of the present invention is 706 cps at a stage temperature of 25 ° C. and 543 cps at a stage temperature of −20 ° C. That is, it can be seen that the peak intensity of the sample TiOx film formed by the prior art is larger than the peak intensity of the sample TiOx film formed by the semiconductor manufacturing method according to the first embodiment of the present invention. In the prior art, the Ti film is oxidized by the oxidized species released from the low dielectric constant insulating film at the time of film formation, and the release of the oxidized species cannot be suppressed during the heat treatment process such as the sintering process, and the oxidation is considered to have progressed. . On the other hand, in the semiconductor manufacturing method according to the first embodiment, oxidation during the formation of the Ti film is suppressed. Therefore, it is considered that a TiOx film having a high molecular density was formed in the heating process after the Ti film was formed, and the progress of oxidation of the Ti film was further suppressed. In the semiconductor manufacturing method according to the first embodiment of the present invention, since the Ti film was not oxidized, the TiCux film was formed in the region where the Ti film and the Cu film were in contact with each other. It can be seen from FIG. The peak intensity of the TiCux film is 224 cps at a stage temperature of 25 ° C. and 210 cps at a stage temperature of −20 ° C. On the other hand, in the prior art, the peak intensity of the TiCux film is 108 cps, which is almost equal to the background intensity or a level that cannot be measured. From the above results, it is considered that the amount of formation of the TiCux film is very small in the prior art, or no TiCux film is formed.

  Furthermore, as a result of the present inventors conducting numerous experiments and earnest studies, when the peak intensity of the TiOx film exceeds 10 when the peak intensity of the TiCux film measured by the 2θ-θ method is 1, the semiconductor device It became clear that the reliability of the system deteriorated. By controlling the formation ratio of the Ti film so that many TiCux films are formed instead of the TiOx film, the TiCux film becomes an adhesion layer between the Cu film and the Ti film, and the SM resistance and EM resistance of the Cu film are reduced. It can be greatly improved. The Cu film, Ti film, and low dielectric constant insulating film of the sample shown in FIG. 16D correspond to the second Cu plating film 70, the second Ti film 30c, and the interlayer insulating film 50 in FIG. . Therefore, according to the semiconductor device according to the first embodiment of the present invention, the semiconductor device includes a stacked structure in which an insulating film, a metal film, and a wiring metal film are stacked in this order on the substrate. A semiconductor device in which the diffraction intensity of the oxide of the metal film by X-ray diffraction measurement is 10 times or less than the diffraction intensity of the compound of the metal film and the wiring metal film can be realized. For example, as shown in FIG. 12, the substrate 10 has a laminated structure in which an interlayer insulating film 50, a second Ti film 30c, and a second Cu plated film 70 are laminated in this order, and an X-ray in the laminated structure. A semiconductor device in which the diffraction intensity of the Ti oxide by the diffraction measurement method is 10 times or less than the diffraction intensity of the compound of the second Ti film 30c and the second wiring layer 70 can be realized.

A multilayer wiring is formed by repeating the steps described in FIGS. 1 to 12, and then a Cu pad or an Al pad for electrodes is formed. Then, multilayer annealing is performed as a final process. If the second Ti film 30c is formed at a temperature lower than the processing temperature in the degassing process step in a reducing atmosphere such as H ₂ or the like, if the second Ti film 30c is formed, As a forming method, a CVD method or an ALD method can be adopted in addition to the PVD method.

Usually, in order to sufficiently remove H ₂ O, OH group or free carbon-based gas contained in the low dielectric constant insulating film in a short time, heating at 350 ° C. to 400 ° C. is required in the degassing process. And Therefore, when the degassing process or the H ₂ reduction heating process is performed at 250 ° C. to 300 ° C. as in the method described above, the interlayer insulating film 50 includes H ₂ O, OH group of thermal budget difference, Free carbon-based gas remains. Oxidation of the second Ti film 30c in the vicinity of the interface between the interlayer insulating film 50 and the second Ti film 30c by a solid-phase reaction with the second Ti film 30c due to these residual oxidation species or free radicals containing carbon. (Hereinafter referred to as “Ti post-oxidation”).

The post-Ti oxidation occurs even at a temperature lower than 300 ° C., which is the upper limit of the temperature in the degassing process described above. This is because the diffusion of H ₂ O proceeds even at 300 ° C. or lower depending on the concentration gradient of the oxidizing species component in the interlayer insulating film 50. In addition, a thermal process for positively oxidizing the second Ti film 30c after Ti may be performed after the multilayer wiring is formed. Alternatively, the post-Ti oxidation can be performed by selecting a temperature of 250 ° C. to 300 ° C. at the time of annealing for stabilizing the film quality of the second Cu plating film 72. It is also effective to perform a thermal process in which post-Ti oxidation is performed before the process of forming the second Cu plating film 72. For example, the PVD method for forming the second Cu seed film 71 is generally performed at room temperature or lower. However, when the CVD method or the ALD method is used for the second Cu seed film 71, the temperature at which the second Cu seed film 71 is formed is set higher than the temperature at which the second Ti film 30c is formed. Ti post-oxidation can be performed.

As shown in the Ti—O2 binary phase diagram, the Ti oxide formed by the solid phase diffusion / solid phase oxidation reaction of the Ti film has a higher concentration of oxygen dissolved than other metal materials. Therefore, in the oxygen solid solution region, the weight molecular density of the Ti oxide is higher than the weight atomic density of pure Ti of 4.507 g / cm ³ . For example, the weight molecular density of titanium oxide (II) (TiO) is 4.93 g / cm ^3, the weight molecular density pentoxide titanium _(Ti 3 _{O 5)} is 4.6 g / cm ^3. Even the titanium oxide TiO ₂ formed when oxygen is present up to 60 atom%, the weight molecular density is 4.26 g / cm ³ , which is 80% or more of the weight atom density of Ti atoms. Magnesium (Mg) has the same characteristics as Ti, and the weight molecular density of Mg oxide is higher than the weight atomic density of pure Mg. The use of such a material having a solid solution form of oxygen as the barrier metal film is effective in blocking the oxidized species released from the insulating film because the formed molecular weight of the oxide is high. . Furthermore, as a result of experiments, it has become clear that a metal oxide having a weight molecular density of 80% or more of the weight atom density of a pure metal is more desirable. Since the barrier metal film is oxidized after the adhesion portion between the Cu film and the barrier metal film is formed as described above, the Ti film remains in a part of the region including the portion that maintains the adhesion with the Cu film. The adhesion between the Ti film and the Ti film does not deteriorate. Further, according to the method of manufacturing the semiconductor device according to the first embodiment, in the metal film in contact with both the wiring metal film and the insulating film, the atomic or molecular density of the metal in the portion where the metal film is in contact with the wiring metal, A semiconductor device can be realized in which the metal atom or molecular density of the portion sandwiched between the wiring metal film and the insulating film is higher than the metal atom or molecular density of the portion where the metal film is in contact with the insulating film. In the semiconductor device shown in FIG. 1 to FIG. 12, in the second Ti film 30c in contact with both the second Cu plating film 72 and the interlayer insulating film 50, the oxygen concentration in the second Ti film 30c is increased. By providing the gradient along the thickness direction, the Ti or atomic density of the portion where the second Ti film 30 c is in contact with the second Cu plating film 72 and the second Ti film 30 c are connected to the interlayer insulating film 50. A semiconductor device in which the Ti atom or molecular density of the portion sandwiched between the second Cu plating film 72 and the interlayer insulating film 50 is higher than the Ti atom or molecular density of the portion in contact therewith can be realized.

  An example in which the O / Ti intensity ratio of the titanium oxide (TiOx) film formed near the interface between the interlayer insulating film and the Ti film after the post-Ti oxidation and the Ti film on the Cu film side is shown below. First, a transmission electron microscope (TEM) analysis sample is created. Then, TEM-electron energy loss spectroscopy (EELS) analysis of the analysis sample is performed. The analysis samples are respectively created by the semiconductor device manufacturing method and related technology according to the first embodiment. At this time, the sample thickness of the measurement sample produced by each manufacturing method is made the same. By EELS analysis, the Ti strength and oxygen strength of the above-described analysis sample formed at room temperature, for example, were obtained. As a result of observation of the groove sidewall, the Cu side O / Ti strength ratio was determined to be O / Ti on the insulating film side. It was found that the O / Ti intensity ratio on the Cu side was lower than 0.12 (about 0.11), which was lower than the Ti intensity ratio. Further, almost no volume expansion of the Ti film was observed. From the above, it is speculated that the state of the Ti film in contact with the Cu film is particularly close to the state in which oxygen is dissolved. Furthermore, FIG. 17 shows the results of evaluating the ratio of Ti intensity to oxygen intensity by EELS analysis for the Ti film on the via hole side wall of the analysis sample subjected to TEM analysis. In FIG. 17, a temperature T1 is a substrate temperature when the barrier metal film is formed by the method for manufacturing a semiconductor device according to the first embodiment, for example, 25 ° C. The temperature T2 is a substrate temperature when the barrier metal film is formed by the related technique, and is equal to or higher than the substrate temperature in the degassing step. As shown in FIG. 17, the O / Ti strength ratio is 0.1 or less.

  As described above, the O / Ti intensity ratio is less than 0.12 at a place where it is in contact with the interface with the Cu film from which the TiOx film has been removed and there is almost no change in the thickness of the Ti film. From this, it is inferred that the O / Ti intensity ratio is less than 0.12 in a state where the Ti film is dissolved in oxygen. Assuming that the O / Ti intensity ratio according to the EELS analysis corresponds to the atomic ratio, this numerical value also coincides with the oxygen solid solution concentration at the process maximum temperature (400 ° C.) shown in FIG. . If the solid solution concentration of oxygen is 420 ° C., the O / Ti atomic ratio is 0.123, and if it is 450 ° C., the O / Ti atomic ratio is 0.15.

  As described above, there is almost no change in the density of Ti due to the solid solution of oxygen in the Ti film, and unlike a tantalum (Ta) film or other oxidized form material, the TiOx film has a large diffusion path increase due to grain boundaries. Is suppressed. As described above, in the Ti post-oxidation step, oxygen due to oxidation species from the interlayer insulating film side is contained in the TiOx film up to the solid solution concentration of oxygen in Ti. Since a compound is formed at the interface with the Cu film, adhesion between the Ti film and the Cu film is ensured.

Further, even if the Ti film is entirely in a form containing oxygen, since the interfacial reaction product between the Ti film and the Cu film is formed, the adhesion between the Ti film and the Cu film does not deteriorate. Further, a step of forming an additional Ti film after the Ti film is partially or entirely oxidized may be performed. Furthermore, after the Ti film is partially or entirely oxidized, a metal film different from Ti such as Ta having a low solid solubility of oxygen may be formed. A metal film such as Ta formed on a high-density Ti oxide effectively functions as an adhesion layer with the Cu film. In that case, since the Ti oxide existing between the Ta film and the insulating film blocks oxidizing species such as H ₂ O released from the insulating film, oxidation of the Ta film is suppressed. Therefore, it can be used more stably as a barrier metal film than when a Ta film is used alone. FIG. 18 shows an example in which a Ta film 36 is formed on the TiOx film 35. Ti, Mg, zirconium (Zr), vanadium (V) and the like are promising as a material having a high concentration for dissolving oxygen.

  As a material for the film formed on the Ti film, it is of course possible to select a material that is difficult to be oxidized or is an oxide and has good adhesion with the Cu film. For example, ruthenium (Ru), palladium (Pd), Examples include platinum (Pt) and gold (Au).

  In the above description, it has been shown as a desirable mode that post-oxidation is performed on a material that easily dissolves oxygen (for example, Ti) at the interface with the insulating film. For example, the mixed film is formed by using an alloy target as a barrier metal film. Of course, it is possible to oxidize the barrier metal film in a post-oxidation step. For example, examples of the alloy include TiRux, TiPdx, TiPt, TiAux, and the like. In these materials, Ti in contact with the interface between the insulating film and the barrier metal film is likely to be oxidized first. Therefore, the same effect as that obtained when the barrier metal film of the Ti film is post-oxidized can be obtained.

Desirable conditions as heat treatment conditions for post-Ti oxidation are shown below. The effect of the reaction between the Ti barrier metal film and the Cu film has the following effects in addition to the improvement of the stress migration resistance and the electromigration resistance described above. That is, the presence of Ti atoms in the Cu film, particularly at the Cu grain boundaries, suppresses the diffusion of Cu atoms. However, in order to obtain the effect of suppressing the diffusion of Cu atoms in a realistic manufacturing process time, for example, 30 minutes or 1 hour, the heat treatment temperature is insufficient at 150 ° C., and a heat treatment step of 200 ° C. or higher is required. . In FIG. 19, the result of having performed the secondary ion mass spectrometry (SIMS) of the sample created with the following method is shown. The sample creation method is as follows. A Ti film having a thickness of 10 nm is formed by ionized PVD. Next, a 46 nm Cu seed film is formed by ionized PVD. Further, a Cu film is formed to 120 nm by a copper wiring plating (ECP) apparatus. Then, a heat treatment step of post-Ti oxidation is simulated, and heat treatment is performed in a reducing atmosphere of H ₂ gas for 1 hour at each temperature shown in FIG. FIG. 19 shows the maximum concentration of Ti in the Cu film from the Ti / Cu interface to 0.2 nm in the above sample. As shown in FIG. 19, the heat treatment temperature exceeding 150 ° C. is effective for suppressing the diffusion of Cu atoms by diffusing Ti atoms in the Cu film.

  Thus, in order to diffuse Ti atoms and add them to the Cu film, a heat treatment exceeding 150 ° C. is desirable. On the other hand, if a sufficient compound is formed at the Ti / Cu interface, the formed compound There is a possibility that the effect of addition of Ti atoms to the desired Cu film cannot be obtained due to the rate limiting by the Ti diffusion therein. In addition, when high-temperature heat treatment is performed from the beginning, a large amount of Ti atoms are added to the Cu film, and a large amount of Ti and Cu compounds are formed at the Ti / Cu interface. There is a possibility that it is not well balanced. In other words, the formation of the compound may affect the oxidation of the Ti film by the oxidizing species released from the insulating film, and the Ti oxide having the desired characteristics may not be formed.

  In order to control these reactions, Ti atoms are added to the Cu film by heat treatment at the first heating temperature at which diffusion from the Ti film to the Cu film is not suppressed by the Ti / Cu compound. At the same time, an interface oxide layer is formed at the interface between the Ti film and the insulating film by releasing the oxidizing species from the insulating film. Next, heat treatment is performed at a second heating temperature higher than the first heating temperature to generate a Ti / Cu compound by a reaction between the Ti film and the Cu film, thereby improving the adhesion between the Ti film and the Cu film. That is, the heating step for desirable post-oxidation includes a heat treatment at the first heating temperature and a heat treatment at the second heating temperature. The above heat treatment not only effectively controls the diffusion of Ti atoms into the Cu film and adjusts the formation of the compound layer at the Ti / Cu interface, but also forms an oxide layer initially at the insulating film / Ti film interface. ing. Therefore, there is also an effect that the supply of oxygen can be controlled by the oxide layer even during the high temperature treatment after the oxide layer is formed.

However, as the oxidation of the Ti film progresses, the advantageous characteristics of the TiOx film described above can be obtained. On the other hand, if the heat treatment is performed at a high temperature, the reaction between the Ti film and the Cu film becomes excessive and the resistance of the damascene wiring increases. To do. FIG. 20 shows an example of the ratio of the resistivity after annealing to the resistivity before annealing of a sample simulating damascene wiring. In the sample whose resistivity change was shown in FIG. 20, a barrier metal film and a Cu film were formed to 10 nm and 100 nm, respectively, by ionization PVD, and then annealed in a hydrogen / argon heated atmosphere. The resistivity ratio indicated by black circles in FIG. 20 is an example in which the barrier metal film is Ti. The resistivity ratio indicated by white circles in FIG. 20 is an example in which the barrier metal film is Ta. As shown in FIG. 20, when the annealing temperature exceeds 450 ° C., the resistivity after annealing increases. For this reason, post-Ti oxidation is performed at a temperature not increasing the resistivity, thereby causing a reaction between the Ti film and the Cu film and diffusion of Ti atoms into the Cu wiring. For example, if the annealing temperature is up to about 400 ° C., Ti atoms diffuse into the Cu film by about 1E20 atoms / cm ^3, but the wiring resistance does not increase. By appropriately selecting the annealing temperature for the post-Ti oxidation as described above, various effects can be obtained by the reaction between the Ti film and the Cu film. The above annealing temperature is an example, and the annealing temperature for post-Ti oxidation is not limited to the above annealing temperature.

  In order to reduce the contact resistance between the wirings, it is desirable that the oxygen concentration in the oxide of the barrier metal film at the portion in contact with the lower layer wiring is lower. As already described, the barrier metal film is oxidized by the oxidizing species released from the interlayer insulating film. By optimizing the temperature of the barrier metal film deposition process and the degassing treatment from the interlayer insulating film as a pre-treatment, the oxygen concentration in the oxide of the barrier metal film at the location in contact with the lower layer wiring can be reduced. It can be made lower than the oxygen concentration in the oxide of the barrier metal film at the point of contact. As a result, it is possible to reduce the contact resistance between the wirings without deteriorating the barrier property of the portion that contacts the insulating film.

  For example, before the barrier metal film forming step (see FIG. 8), heat treatment is performed for 10 to 600 seconds in a vacuum of 200 ° C. to 350 ° C. as pretreatment. By controlling the amount of oxidizing species released from the interlayer insulating film by this heat treatment, the oxygen concentration in the oxide of the barrier metal film formed on the surface of the lower wiring is insulated during the subsequent formation of the barrier metal film. The oxygen concentration in the oxide of the barrier metal film formed on the portion in contact with the film can be made smaller. That is, the oxygen concentration of the oxide of the second Ti film 30 c shown in FIG. 12 is lower in the portion in contact with the first wiring layer 40 than in the portion in contact with the interlayer insulating film 50.

FIG. 21 shows the molecular densities of the Ti film and the TiOx film. As shown in FIG. 21, when the oxygen content in the TiOx film is smaller than that of the Ti ₃ O ₅ film, the molecular density of the TiOx film is larger than the molecular density of the Ti film. That is, the barrier property of the TiOx film having an atomic ratio of oxygen to Ti of 5/3 or less is higher than that of the Ti film. For this reason, the atomic ratio of oxygen to Ti in the oxide film obtained by oxidizing the second Ti film 30c is desirably 5/3 or less.

  In the description of the manufacturing method of the semiconductor device according to the first embodiment, it has been shown that the second Cu seed film 71 is performed by any one of the PVD method, the CVD method, and the ALD method. After forming 71 by the PVD method, it is also possible to bury part or all of the via hole 203 and the second wiring groove 202 by the CVD method or the ALD method. Further, the second Cu seed film 71 may be formed after the second Ti film 30c is formed by the CVD method or the ALD method, or the embedding process may be performed as it is. Needless to say, the embedding step can be directly performed by plating after the formation of the second Ti film 30c.

  In the semiconductor device manufacturing method according to the first embodiment, the molecular density is changed in the thickness direction of the barrier metal by introducing oxygen into the Ti film mainly constituting the barrier metal film. . In such a case, generally, a stress gradient may be generated to cause film peeling. However, in the method of manufacturing the semiconductor device according to the first embodiment of the present invention, the degassing process step is performed such that the Ti film closer to the insulating film has a lower molecular density and the closer to the Cu side, the higher the molecular density. It was found that the stress gradient was relaxed and the problem of the barrier metal peeling off from the insulating film and Cu was eliminated by adjusting the temperature of and the temperature of the Ti forming step.

(Second Embodiment)
The method for manufacturing a semiconductor device according to the second embodiment of the present invention is a method for oxidizing a metal film having a characteristic of dissolving oxygen with a gas other than the gas released from the insulating film. An example of a method for manufacturing a semiconductor device according to the second embodiment will be described below. Hereinafter, a case where the second Ti film 30c is formed as the metal film 30 on the interlayer insulating film 50 shown in FIG. 8 will be described as an example.

(A) The substrate 10 is degassed in a vacuum or in a reducing atmosphere such as H ₂ gas at a temperature of 250 ° C. or higher and 300 ° C. or lower, for example, by a process similar to the process described in the first embodiment. . As a result, carbon-based residues and the like remaining in the interlayer insulating film 50 are removed. At the same time, the oxide film on the surface of the first wiring layer 40 exposed at the bottom of the via hole 203 is reduced.

  (B) Next, a barrier metal film is formed on the substrate 10 by continuous vacuum. For example, it is transferred into an ionization sputtering chamber as shown in FIG. Then, the substrate 10 is transferred onto a susceptor that is set to at least the heating temperature in the degassing process step of the interlayer insulating film 50, preferably below room temperature, and the temperature of the substrate 10 is maintained at a temperature equivalent to that of the susceptor. Next, as shown in FIG. 9, a second Ti film 30c is formed by ionized sputtering.

(C) Next, the pressure in the ionization sputtering chamber shown in FIG. 13 is higher than the degree of vacuum at which the second Ti film 30c is formed, for example, 0.5 × 10 ⁻⁵ Pa, for example, 1 × 10. Argon (Ar) gas, nitrogen (N ₂ ) gas, and O ₂ gas or H ₂ O are introduced into the ionization sputtering chamber so as to be ⁻⁵ Pa and held for 60 seconds, and then the gas is exhausted. As a result, Ti oxide is formed on the surface of the second Ti film 30c. Then, the substrate 10 is cooled to a temperature equivalent to that when the second Ti film 30c is formed, and the second Ti film 30c is additionally deposited so as to finally have a desired film thickness. At this time, it is preferable that the pressure when the second Ti film 30c is formed before the Ti oxide is formed is equal to the pressure in the ionization sputtering chamber. When the pressure at the time of oxidizing the second Ti film 30c is equal to the atmospheric pressure, the oxidation state of the second Ti film 30c cannot be controlled. Therefore, when the substrate 10 is exposed to the atmosphere and returned to the ionization sputtering chamber again, it is impossible to realize a state in which oxygen is dissolved in the second Ti film 30c.

As described above, according to the method for manufacturing the semiconductor device according to the second embodiment, the surface of the second Ti film 30c is oxidized during the formation of the second Ti film 30c having a high atomic density. Thus, a Ti oxide having a higher molecular density is formed, and the entire second Ti film 30c can be prevented from being oxidized by an oxidizing species such as H ₂ O released from the interlayer insulating film 50. Therefore, a pure Ti film having good adhesion with the Cu film can be left as the second Ti film 30c in the vicinity of the interface with the Cu film. Furthermore, by performing the Ti post-oxidation step described in the first embodiment, Ti oxidation near the interface between the second Ti film 30c and the interlayer insulating film 50 is promoted. As a result, Ti oxide is formed in the second Ti film 30c, and the diffusion of oxidized species from the interlayer insulating film 50 to the Cu film is suppressed. That is, the function of the barrier metal film as an adhesion layer with the Cu film is more effectively ensured. Others are substantially the same as those in the first embodiment, and redundant description is omitted.

Further, as described above, according to the method of manufacturing the semiconductor device according to the second embodiment, the second Ti film 30c is oxidized during the formation of the second Ti film 30c having a high atomic density. Then, it has been explained that the Ti oxide having a higher atomic density is formed. However, after the second Ti film 30c is formed as shown in FIG. It is also effective to form a dissimilar metal and use it for the adhesion layer with the Cu film. At this time, the TiOx layer having a high atomic density in the lower layer suppresses the diffusion of H ₂ O or the like to prevent the Ta film 36 from being oxidized, and the wiring reliability can be improved as compared with the case where the Ta film 36 is used as a single layer. . Furthermore, as a film laminated on the second Ti film 30c, it is very effective when a material that is hardly oxidized or is an oxide and has good adhesion with Cu is selected. For example, Ru, Pd, Pt, Au, etc. are mentioned.

(Third embodiment)
The method of manufacturing a semiconductor device according to the third embodiment of the present invention releases the adsorbed gas in the insulating film in which grooves and via holes are formed on the surface and on the surface at the first substrate temperature. A step of forming a metal film at a second substrate temperature lower than the first substrate temperature, a step of forming a wiring metal film on the metal film in a state where at least a part of the recess is not buried, Heating at a third substrate temperature higher than the substrate temperature of 2 causes oxidation species remaining in the insulating film to oxidize at least a portion of the metal film, and simultaneously forms a reaction layer at the interface between the metal film and the wiring metal film. Process.

For example, as shown in FIG. 8, the second wiring trench 202 and the via hole 203 are formed. Thereafter, heat treatment is performed in a vacuum or a reducing atmosphere such as H ₂ gas at a temperature of, for example, 250 ° C. or more and 300 ° C. or less. By this heat treatment, a part of H ₂ O and the like contained in the interlayer insulating film 50 is removed. At this time, if it is performed in a reducing atmosphere, the oxide film on the surface of the first wiring layer 40 exposed at the bottom of the via hole 203 can be reduced.

  Next, a Ti film is formed as a barrier metal film on the surface of the substrate 10 in a continuous vacuum with good step coverage by using the ionized sputtering method shown in FIG. 13 or the ALD method using light irradiation. At this time, the substrate temperature is at least equal to or lower than the heating temperature in the degassing process of the interlayer insulating film 50.

  Next, a Cu film is formed as a wiring metal film on the Ti film by continuous vacuum. At this time, the Cu film may be formed by ionized sputtering or CVD, but at least part of the second wiring trench 202 and the via hole 203 is formed by the second Cu seed film 71 as shown in the film formation example of FIG. Form so as not to fill.

Next, the substrate is heated, for example, within a range of 250 to 380 ° C., and the second Ti film 30 c in contact with the interlayer insulating film 50 is oxidized by an oxidizing species such as H ₂ O remaining in the interlayer insulating film 50. Then, a CuTi compound is formed at the interface between the second Cu seed film 71 and the second Ti film 30c. This heating process may be performed continuously in vacuum after the formation of the second Cu seed film 71 or may be performed after the atmosphere is released. Further, the heating temperature is preferably equal to the heating temperature for removing a part of H ₂ O or the like contained in the interlayer insulating film 50 or the heating temperature in the subsequent process.

  Next, the second wiring trench 202 and the via hole 203 not filled with the Cu film are shown in FIG. 11 by using a Cu filling method such as plating using the second Cu seed film 71 previously formed as a seed film. Fill completely. Next, the second Cu plating film 72, the second Cu seed film 71, and the second Ti film 30c are removed by CMP to complete a two-layer wiring.

  Generally, when a Cu plating film is formed on a Cu seed film, heat treatment is often performed to increase the crystal grain size. However, if the adhesion between the barrier metal film and the Cu film is low, as shown in FIG. 23, the Cu film in the via hole 203 is sucked up after the heating process, and voids are generated. This is because the Cu film formed in the second wiring groove 202 on the via hole 203 has a large volume, so that stress that pulls the Cu film in the via hole 203 is generated. Further, as shown in FIG. 24, even when the wiring shape is formed by removing the Cu film and the barrier metal film by CMP, the via hole 203 connected to the wide wiring is heated when forming the interlayer insulating film. In addition, voids are generated in the via hole 203 due to heating in the sintering process.

  However, in the method of manufacturing a semiconductor device according to the third embodiment of the present invention, since the substrate is heated in a thin film state such as a Cu seed before completely filling and filling the wiring grooves and via holes, voids due to stress are generated. Does not occur. In particular, even in the case of FIG. 22C in which the via hole 203 is filled with a Cu film, since the volume of the Cu film filled in the wiring groove 202 on the via hole 203 is small, the stress that pulls the Cu film in the via hole 203 is small. Accordingly, a reaction between the Ti film, which is a barrier metal film, and the Cu film occurs during the heat treatment, and a compound layer is formed at the interface between the Ti film and the Cu film. Since this compound layer becomes an adhesion layer between the Ti film and the Cu film, a strong adhesion can be obtained, and voids are not formed even in a heating process that receives subsequent stress. In addition, since an oxide film with a high atomic density is formed at the interface between the insulating film and the Ti film at the same time as the compound layer is formed, it is possible to suppress the release of oxidizing species from the further insulating film and further oxidize the Ti film. Can be suppressed. Further, as described in the first embodiment, an oxide film having a high molecular density is simultaneously formed at the interface between the Ti film and the insulating film during heating in a thin film state such as a Cu seed. Of course, defects due to diffusion of oxidized species in the heating process can be suppressed.

  In addition, it is desirable to adjust the sputtering conditions so that the second Cu seed film 71 formed using the ionized sputtering method has a conformal shape. However, depending on the conditions, as shown in FIG. 25A, an overhang-shaped protrusion may occur in the opening of the via hole 203 or the opening of the second wiring groove 202. Such overhang-like protrusions obstruct the ingress of the plating solution in the subsequent plating process, and as a result, block the opening of the second wiring groove 202 and the via hole 203, leaving a void in the wiring and the via hole. . However, when the heat treatment is performed after forming the second Cu seed film 71 as in the method of manufacturing a semiconductor device according to the third embodiment of the present invention, the second Cu seed film 71 is stabilized by lowering the surface energy. The surface diffuses so as to reduce the surface area in an attempt to obtain a simple shape. That is, as shown in FIG. 25 (b), the overhang-shaped protrusions are flattened, and the shape can be made more conformal. In particular, when the second Cu seed film 71 is formed and then heat treatment is continuously performed in vacuum, this effect is great. Therefore, according to the method of manufacturing a semiconductor device according to the third embodiment of the present invention, the problem of void generation can be solved without hindering the ingress of the plating solution into the second wiring trench 202 or the via hole 203.

In addition, when a Cu film is filled in a groove or a via hole using a plating method, the Cu film formed by the plating method contains a lot of oxidizing species such as O ₂ and H ₂ O. On the other hand, a Cu seed film formed by ionization sputtering or a Cu seed film formed by CVD is formed under reduced pressure with few residual impurities, so that there are few oxidizing species. However, when a Cu film is formed by plating on a Cu seed film with few oxidizing species, the oxidized seed in the Cu film formed by plating in the heating step after the plating step passes through the thin seed Cu film, and the barrier The metal film may be oxidized. As described above, the oxidized barrier metal film has low adhesion with the Cu film, and the reliability decreases. In this case, the second Cu seed film 71 on the side wall of the via hole 203 is thickened using the CVD method as shown in FIG. 22B, or the entire via hole 203 is used using the CVD method as shown in FIG. Is filled with the second Cu seed film 71, the influence of the oxidized species from the second Cu plating film 72 filling the via hole 203 can be reduced. That is, the oxidation of the second Ti film 30c in the via hole 203 can be suppressed. In particular, the effect when the via hole 203 is completely filled with the second Cu seed film 71 by using the CVD method is great (FIG. 22C). Therefore, the adhesion between the Cu film and the barrier metal film in the via hole 203 is not deteriorated, and no void is generated even if a stress that pulls the Cu film in the via hole 203 is generated in the subsequent heating process.

(Fourth embodiment)
In the method for manufacturing a semiconductor device according to the fourth embodiment of the present invention, at a first substrate temperature, an oxidizing species adsorption gas on the surface and in the insulating film in which recesses such as grooves and via holes are formed are formed. A step of releasing, a step of depositing the source gas on the surface of the recess at a second substrate temperature lower than the first substrate temperature, and exhausting the remaining source gas not attached to the surface of the recess, To decompose the molecules of the source gas adhering to the concave surface to form a metal film made of metal atoms contained in the component of the raw material gas on the concave surface.

For example, as shown in FIG. 26 (a), when titanium tetrachloride (TiCl ₄ ) gas as a raw material gas is introduced into a chamber for performing a thin film forming process by adjusting the pressure and flow rate, the surface of the insulating film 20 is introduced. Adsorbs TiCl ₄ molecules uniformly. By the way, when an insulating film having a low dielectric constant is employed as the insulating film 20, the insulating film 20 includes many holes in order to lower the dielectric constant. Then, oxidized species such as water and oxygen absorbed when the atmosphere is released remain in the insulating film 20. Therefore, when the insulating film 20 is heated in order to decompose the TiCl ₄ molecules adhering to the surface of the insulating film 20, the adsorbed gas is released from the side surface of the recess 200. As a result, the titanium (Ti) film, which is the metal film 30 formed by decomposing TiCl ₄ molecules, and the oxidized species released from the insulating film 20 are combined to deteriorate the characteristics of the Ti film. Therefore, before the metal film 30 is formed, a step of releasing oxidized species in the insulating film 20 is performed. Further, in the process of forming the metal film 30, it is necessary to keep the temperature of the insulating film 20 lower than the temperature in the process of releasing the oxidized species. As shown in FIG. 26B, according to the method of promoting the decomposition of the adsorbed molecules by the light energy of the irradiation light 111, the temperature of the insulating film 20 can be kept low.

  FIG. 27 shows a cross-sectional configuration of a semiconductor manufacturing apparatus that can be used in the semiconductor device manufacturing method according to the fourth embodiment of the present invention. The semiconductor manufacturing apparatus shown in FIG. 27 includes a chamber 100 and a light source 110, and is connected to a gas supply system and an exhaust system (not shown). The chamber 100 includes a susceptor 101 on which the substrate 10 is installed, a light transmission window 102, an openable / closable shielding plate 103 that shields the light transmission window 102, and a gas introduction unit 104 that introduces gas into the chamber 100. The substrate 10 is irradiated with irradiation light 111 from the light source 110 that has passed through the light transmission window 102. Further, the irradiation light 111 is shielded by the shielding plate 103 as necessary. The chamber 100 is connected to a transfer chamber (not shown) provided with a substrate transfer mechanism, and the substrate is continuously vacuumed by another chamber connected to the transfer chamber before or after the film formation process in the chamber 100. Ten different processes can be performed.

  Hereinafter, an example of a semiconductor device manufacturing method using the semiconductor manufacturing apparatus shown in FIG. 27 will be described with reference to FIGS. The semiconductor device manufacturing method described below is merely an example, and it is needless to say that the present invention can be realized by various other semiconductor device manufacturing methods including this modification. Hereinafter, a method for manufacturing a semiconductor device in which a Ti film is formed as the metal film 30 on the surface of the insulating film 20 will be described.

(A) Heating at about 250 ° C. to 300 ° C. is performed in a separate chamber (not shown) connected to the transfer chamber to degas the adsorbed gas adsorbed on the insulating film 20. At this time, if the Cu wiring is arranged under the insulating film 20 and the Cu wiring is exposed at the bottom surface of the via hole, H ₂ reduction treatment is performed on the surface of the Cu wiring by introducing H ₂ and performing degassing treatment. Can be performed simultaneously. Alternatively, it is possible to perform a H ₂ reduction process on the Cu wiring surface before and after the degassing process.

  (B) Next, the substrate 10 is transferred from the transfer chamber onto the susceptor 101 in a continuous vacuum as shown in FIG. At this time, the temperature of the substrate 10 is set to be lower than at least the temperature of the substrate 10 in the degassing process. For example, the temperature of the substrate 10 is set to 150 to 200 ° C.

(C) Next, as shown in FIG. 28, TiCl ₄ gas, which is a raw material gas for the Ti film, is introduced from the gas supply system via the gas introduction unit 104 with the shielding plate 103 closed. Since the boiling point of TiCl ₄ is 136.4 ° C., if the temperature of the substrate 10 is set equal to or higher than the boiling point of TiCl ₄ , it is adsorbed on the surface of the insulating film 20 as a TiCl ₄ molecular layer without condensing on the substrate 10. Further, TiCl ₄ is because it is liquid at room temperature, is vaporized TiCl ₄ in omitted vaporizer shown, using Ar gas, _{N 2} gas, helium (He) gas, a carrier gas such as H ₂ gas chamber Introduce within 100.

(D) After introducing the TiCl ₄ gas into the chamber 100 for a predetermined time, the introduction of the TiCl ₄ gas is stopped with the shielding plate 103 closed as shown in FIG. Next, the TiCl ₄ gas remaining in the chamber 100 is exhausted.

(E) As shown in FIG. 30, the shielding plate 103 is opened, and the irradiation light 111 from the light source 110 is transmitted through the light transmission window 102 and irradiated onto the substrate 10. The TiCl ₄ molecules adsorbed on the surface of the insulating film 20 are decomposed by the energy of the irradiation light 111, and a Ti thin film layer is formed on the insulating film 20. At this stage, a reactive gas such as H ₂ gas may be introduced. The case of introducing H ₂ gas as the reactive gas, H ₂ gas to the irradiation light 111 is irradiated becomes active hydrogen radicals dissociated (H ^*), the decomposition of TiCl ₄ molecules are further promoted.

  Through the above steps, a Ti atomic layer is formed on the surface of the insulating film 20. Then, the above process is repeated to form a Ti film having a desired film thickness. As the low dielectric constant insulating film 20, a PAE film, a SiCO film, or the like can be applied.

  For example, when a mechanism is provided that moves the position of the susceptor 101 up and down in the chamber 100, the height of the susceptor 101 may be adjusted to be low so that the exhaust efficiency is increased in the process of exhausting residual components of the source gas. Good. 27 to 30 show an example in which the raw material gas is introduced from one gas introduction unit 104, a plurality of gas introduction units 104 are provided in order to improve the uniformity of the raw material gas in the chamber 100. May be. Alternatively, the source gas may be introduced into the shielding plate 103 from the gas introduction unit 104 and the source gas may be introduced into the chamber 100 through a plurality of holes provided in a portion of the shielding plate 103 facing the substrate 10. As a result, the adsorption of source gas molecules is made uniform on the surface of the insulating film 20, and the uniformity of the formed film thickness can be improved.

  The wavelength of the irradiation light 111 may be selected according to the light absorptivity of the source gas molecules. For example, when an excimer lamp is used, the wavelength of the irradiation light 111 is selected as follows according to the type of gas used for the excimer lamp. That is, an excimer lamp having a single wavelength such as Ar excimer: 126 nm, krypton (Kr) excimer: 146 nm, xenon (Xe) excimer: 172 nm, krypton chloride (KrCl) excimer: 222 nm, xenon chloride (XeCl) excimer: 308 nm is selected. . When a mercury lamp is used, light including a plurality of wavelengths such as 185 nm and 254 nm can be selected. The irradiation energy and irradiation time of the irradiation light 111 are adjusted according to the aspect ratio of via holes and wiring grooves formed on the substrate 10.

The standard production enthalpy of TiCl ₄ molecules used in the above description is represented by the following formulas (1) and (2):

TiCl ₄ (gas) → Ti (solid) + 2Cl ₂ (gas) (1)
Standard generation enthalpy ΔHf ° = 763 kJ / mol (2)

From the formulas (1) and (2), the standard enthalpy of formation per molecule of TiCl ₄ is 1.27 × 10 ⁻¹⁵ J. Since the TiCl ₄ molecule has four Ti—Cl bonds, the bond dissociation energy of one Ti—Cl bond is 3.17 × 10 ⁻¹⁶ J. The wavelength of light for obtaining bond dissociation energy of Ti—Cl bond is 627 nm or less. The light absorption wavelength of the TiCl ₄ molecule has maximum values at 280 nm and 232 nm. Therefore, 627 nm or less, and by using the light having a wavelength of maximum absorption wavelength near the TiCl ₄ molecules as the irradiation light 111, it can degrade TiCl ₄ molecules efficiently. When the irradiation light 111 is selected from an excimer lamp, an Xe excimer (wavelength: 172 nm), a KrCl excimer (wavelength: 222 nm), or an XeCl excimer (wavelength: 308 nm) can be selected. Further, mercury lamps having wavelengths of 185 nm and 254 nm can be used as the irradiation light 111. Further, there is no need for a light source in a narrow wavelength band, and a light source in a wide wavelength band may be used. Further, recent low dielectric constant insulating films are formed by curing (sintering, polymerizing, or condensing) a precursor by heating, electron beam irradiation, UV light irradiation, or the like. When such a low dielectric constant insulating film is further irradiated with UV light, the bonds that should be bonded to each other are cut off and the dielectric constant may be increased in some cases. In such a case, a wavelength that does not affect the insulating film may be selected in accordance with the properties of the insulating film to be used. In particular, curing by UV light irradiation (generally referred to as UV curing) is limited to a certain region of energy, so that only specific and necessary bonds can be dissociated. In this case, even if UV light irradiation is performed for a long time, unnecessary decomposition does not occur and the properties of the low dielectric constant insulating film do not change. Therefore, if the wavelength of the light used in the fourth embodiment is matched with the wavelength of the UV cure of the low dielectric constant insulating film, the insulating film will not be damaged.

Incidentally, at the bottom of the recess 200 in FIG. 26A, the irradiation light 111 is less likely to reach compared to the surface of the other insulating film 20, so that the decomposition rate of TiCl ₄ molecules is slow. For this reason, even after the time necessary for the decomposition of the TiCl ₄ molecules on the surface of the insulating film 20 by the irradiation light 111 has elapsed, the decomposition of the TiCl ₄ molecules may not sufficiently proceed at the bottom of the recess 200. Accordingly, the intensity and irradiation time of the irradiation light 111 are adjusted so that the decomposition ends at the bottom of the recess 200 that takes the longest time to decompose because the irradiation light 111 is difficult to hit. Then, as shown in FIG. 26B, titanium (Ti) atoms are uniformly adsorbed on the surface of the insulating film 20. FIG. 31 shows an example in which the irradiation time is set to a time necessary for decomposition of TiCl ₄ molecules in the region R near the surface of the insulating film 20 in the recess 200. As shown in FIG. 31, even after the TiCl ₄ molecules on the region R and the surface of the insulating film 20 are decomposed, the decomposition of the TiCl ₄ molecules does not proceed sufficiently at the bottom of the recess 200.

FIGS. 32A to 32C show an example in which a Ti film is formed by a photo-CVD method that irradiates the irradiation light 111 while introducing the source gas TiCl ₄ . As shown in FIG. 32A, in the photo-CVD method in which the irradiation light 111 is irradiated while introducing the source gas TiCl ₄ , the decomposition rate of TiCl ₄ at the front of the recess 200 is fast, and the decomposition of TiCl ₄ at the bottom is performed. The speed is slow. For this reason, first, a thick Ti film is formed at the opening of the recess 200, and the source gas TiCl ₄ is difficult to enter at the bottom. As a result, as shown in FIGS. 32B and 32C, the step coverage of the Ti film is low, and there is a problem that a film containing a lot of Cl atoms as impurities is formed at the front of the recess 200. Further, since the irradiation light 111 is irradiated while flowing the source gas, a Ti film or the like adheres to the surface of the light transmission window 102 that transmits the irradiation light 111 on the chamber 100 side, and the intensity of the irradiation light 111 gradually decreases. There is a problem.

On the other hand, as described with reference to FIGS. 27 to 30, in the method of manufacturing a semiconductor device according to the fourth embodiment of the present invention, the Ti film is formed in units of atomic layers using the ALD method. The low step coverage due to the difference in the decomposition rate of the source gas at the front and bottom of the recess 200, which was a problem in the photo-CVD method, can be solved, and an extremely conformal Ti film can be formed. . In addition, as described with reference to FIGS. 27 to 30, the irradiation with the irradiation light 111 and the introduction of the source gas are performed in separate steps. Therefore, when the TiCl ₄ gas is introduced, the light transmission window 102 is covered with the shielding plate 103, and there is no problem of adhesion of the Ti film to the light transmission window.

  Further, as described above, the method of promoting the decomposition of the adsorbed molecules by the light energy of the irradiation light 111 can keep the temperature of the substrate 10 low. In order to form a Ti film as a barrier metal film on the insulating film 20 having a high hygroscopicity and a low dielectric constant, as described in the explanation of FIG. 27, the temperature of the substrate 10 is set to the temperature of the substrate 10 in the degassing process. It is important to set the Ti film to a lower value. This is because when the Ti film is formed with the temperature of the substrate 10 higher than the degassing temperature, the Ti film is formed while the oxidized species that are adsorbed in the insulating film 20 and not released in the degassing process are released. The As a result, as will be described later, an effect such as oxidation of the Ti film occurs. In order to reduce the release of oxidizing species from the insulating film 20 during the formation of the Ti film, the Ti film formation temperature is lowered and the temperature of the substrate 10 is formed before the Ti film is formed. It is effective to perform a heat treatment that raises the temperature or higher. By this heat treatment, oxidizing species contained in the insulating film 20 are removed when the Ti film is formed. Even if the oxidized species contained in the insulating film 20 cannot be completely removed, the released amount of oxidized species during the formation of the Ti film can be reduced.

FIG. 33 shows Ti oxidation during the formation of the Ti film using the fourth embodiment. As shown in FIG. 33A, when oxidized species are released during the decomposition process of TiCl ₄ molecules, Ti atoms are combined with oxygen (O) to form titanium oxide (TiOx). That is, a TiOx film having a low molecular density is obtained by the same mechanism described with reference to FIG. 14 in the first embodiment (FIG. 33B), and as shown in FIG. 33C, the oxidized species is a TiOx film. The Cu film reaches the Cu film and is oxidized, and the SM resistance of the Cu wiring deteriorates.
On the other hand, when the Ti film is formed at a temperature lower than that in the degassing process, the pure Ti film 30a is formed as a barrier metal film as shown in FIG. That is, the TiOx film 35 having a high molecular density is formed in the insulating film forming process and the sintering process after forming the Ti film 30a by the same mechanism as described with reference to FIG. 15 in the first embodiment. (FIG. 34 (c)), the SM resistance of the Cu wiring does not deteriorate.

As already described, as the low dielectric constant insulating film, an inorganic insulating film such as SiCO or an organic insulating film such as PAE is applicable. As a stopper material in the etching process, a SiCN film, a silicon nitride (SiN) film, or the like can be applied. The amount of source gas adsorbed varies depending on the type of insulating film. This is because the termination group of the outermost surface atom varies depending on the type of insulating film. For example, when it is terminated with a CH ₃ group, it exhibits hydrophobicity, and when it is terminated with an OH group, it exhibits a difference in adsorption properties such as hydrophilicity. Therefore, in the dual damascene structure in which a plurality of types of insulating films are stacked to form one interlayer insulating film, the thickness of the barrier metal film formed on different types of insulating films varies. In that case, it is effective to modify the surface of the insulating film by performing light irradiation in advance. For example, if the CH ₃ group is dissociated and removed with a specific light energy, the terminal group becomes an OH group, and even when a metal film is formed on the surface of a plurality of types of insulating films, the adsorption state of the source gas is made uniform. It becomes possible to do. If the source gas is introduced in a state where it can be easily adsorbed, variations in the thickness of the metal film due to the type of insulating film can be suppressed.

In addition, when the recess 200 is formed in the interlayer insulating film, a resist film residue or a by-product generated by a secondary process in the etching process may remain on the substrate 10 to prevent conduction at the bottom of the recess 200. is there. Since such a residue contains carbon (C) and fluorine (F), light irradiation is performed while flowing a decomposable gas such as O ₂ , H ₂ , H ₂ O, and ammonia (NH ₃ ). A step to remove may be included. Alternatively, the resist may be removed by irradiating light while flowing a decomposable gas such as O ₂ , H ₂ , H ₂ O, NH ₃ or the like.

In the above description, an example of forming a Ti film has been described. However, when it is desired to form a titanium nitride (TiN) film, a reactive gas such as N ₂ gas or NH ₃ gas is introduced in the process of FIG. If the introduction of the NH ₃ gas, NH ₃ gas which has received the light irradiation dissociate to active hydrogen nitride radicals (NH ^*) next, to form a TiN film by nitriding the Ti as well as degrade the TiCl ₄ molecule. Further, source gases such as tetrakisdimethylaminotitanium (TDMAT; (Ti [N (CH ₃ ) ₂ ] ₄ )), tetrakisdiethylaminotitanium (TEMAT; (Ti [N (C ₂ H ₅ CH ₃ ) ₂ ] ₄ )), etc. It is also possible to form a TiN film using In the fourth embodiment, an example in which TiCl ₄ that is an inorganic compound is used as a raw material gas has been described. However, a raw material gas of titanium tetrabromide (TiBr ₄ ), titanium tetraiodide (TiI ₄ ), or an organic compound is used. May be used.

  In the above description, an example in which a Ti film is formed as a barrier metal has been described. However, a Cu film serving as a seed for a plating film formed on the Ti film may be formed using a similar film forming method. In this case, an organic metal gas such as hexafluoroacetylacetone copper (I) trimethylvinylsilane adduct / trimethylvinylsilane added (Cu (hfac) TMVS) may be used as the source gas. At this time, the chamber for forming the Ti film and the chamber for forming the Cu film may be separated, or may be formed by switching the source gas in the same chamber. It is also possible to form a Cu film by switching to the conventional CVD method after forming several Cu atomic layers by the method of manufacturing a semiconductor device according to the fourth embodiment of the present invention. When a Cu film is formed on a dissimilar metal by the CVD method, a nucleus for Cu growth is required on the surface of the dissimilar metal, and there is a problem that a uniform Cu film cannot be formed if the nucleus density is low. If a Cu layer is formed in several atomic layers on Ti using the method for manufacturing a semiconductor device according to the fourth embodiment of the present invention, a uniform Cu film can be obtained even by using CVD with a high deposition rate. Can grow. Further, the initial light irradiation promotes the bonding between the Ti film and the Cu film, and is excellent in adhesion at the Ti / Cu interface.

(Fifth embodiment)
The semiconductor device manufacturing method according to the fifth embodiment of the present invention is not the formation of a Ti film as a barrier metal used in the Cu multilayer wiring shown in the first to fourth embodiments, but a memory element. This is a method of forming an aluminum oxide (Al ₂ O ₃ ) film which is a high dielectric film used for capacitance or the like. Hereinafter, a method for forming an Al ₂ O ₃ film on a substrate using the semiconductor manufacturing apparatus shown in FIG. 27 will be described. Hereinafter, a case where trimethylaluminum (TMA; (Al (CH ₃ ) ₃ )) is used as a source gas will be described.

  First, an aluminum (Al) film is formed on the surface of the substrate 10 in the same manner as described with reference to FIGS. That is, the substrate 10 is transferred from the transfer chamber onto the susceptor 101. Next, the shielding plate 103 of the light transmission window 102 is closed, and TMA gas is introduced into the chamber 100. Since TMA is a liquid at room temperature, it is vaporized and introduced into the chamber 100 using a carrier gas such as Ar gas, N gas, He gas, H gas. Then, the substrate 10 is adjusted to a temperature at which the TMA gas does not condense, and the TMA molecules are adsorbed on the substrate 10. Next, the introduction of the source gas is stopped and the TMA gas in the chamber 100 is exhausted. Thereafter, the shielding plate 103 is opened, and the substrate 10 is irradiated with the irradiation light 111 to form an Al thin film on the surface of the substrate 10.

Next, as shown in FIG. 35, oxidizing species such as O ₂ and H ₂ O are introduced into the chamber 100 to oxidize the Al film formed on the substrate 10 to form an Al ₂ O ₃ film. Alternatively, the Al film oxidation process shown in FIG. 35 may be performed after an Al film having a desired film thickness is formed by repeating the processes described with reference to FIGS. Further, in the oxidation step, oxidation may be performed by introducing an oxidation species, or light irradiation may be performed to dissociate the oxidation species to form oxygen radicals, and the oxidation efficiency may be increased by oxygen radicals. Further, this oxidation step may be performed by transporting the substrate 10 to another chamber. Alternatively, the oxidation step may be performed using a separate apparatus after opening to the atmosphere.

It is known that a high-density Al ₂ O ₃ film is formed on the surface of the Al film by oxidation by heating after the Al film is formed. However, since Al is a low melting point metal, when trying to form a very thin Al film, the Al film aggregates and separates into islands on the substrate even at a relatively low temperature, forming a continuous Al thin film. Is difficult. Therefore, it is difficult to form an Al ₂ O ₃ film having a high atomic density after forming an Al ultrathin film by a film forming method that requires heating of the substrate for decomposition of the source gas, such as CVD or ALD. Met. Therefore, an ALD method for decomposing the adsorbed gas while flowing oxidizing species and an ALD method for forming an Al ₂ O ₃ film using a source gas containing oxygen have been studied. However, in the decomposition process, since Al atoms and oxygen are bonded in a state where Al atoms are not bonded to other Al atoms (unbound), as shown in FIGS. 36 (a) and 36 (b). The distance between Al—O atoms is wide. Therefore, as shown in FIG. 36C, an Al ₂ O ₃ film having a low molecular density is formed. The Al ₂ O ₃ film having a low molecular density has many dangling bonds and has problems such as a large leakage current. “Dangling bonds” are dangling bonds occupied by electrons that do not participate in bonding.

On the other hand, according to the method for manufacturing a semiconductor device according to the fifth embodiment of the present invention, as shown in FIGS. 37 (a) and 37 (b), the adsorbed molecules are decomposed with light energy. The substrate 10 need not be at a high temperature, and an Al atomic layer can be formed while suppressing aggregation of the Al film 37. Further, as shown in FIG. 37 (c), after the Al film 37 is formed, the Al film 37 is oxidized while being subjected to self-stress due to the Al—Al bond of the Al film 37, so that the dense Al ₂ O having a high molecular density. _Three films can be formed.

Although the formation of the Al ₂ O ₃ film has been described here, an impurity called hafnium (Hf) may be added to further reduce the leakage current. In this case, a gas containing hafnium may be introduced together with the source gas.

In the above description, an example using TMA has been described. However, dimethylaluminum hydride (DMAH; (Al (CH ₃ ) ₂ H)), dimethylethylamine atene (DMEAA; (AlH ₃ .N (CH ₃ ) (C ₂ A source gas such as H ₅ ))) can be used. It can also be applied to the formation of an oxide film of a metal other than Al, and further, after forming the metal film, nitriding the metal film by introducing a nitriding species, the metal nitride film May be formed. Others are substantially the same as those in the first embodiment, and redundant description is omitted.

(Sixth embodiment)
A semiconductor manufacturing apparatus according to the sixth embodiment of the present invention is shown in FIGS. 38 (a) and 38 (b). The semiconductor manufacturing apparatus shown in FIGS. 38A and 38B can be applied to the semiconductor device manufacturing methods described in the first to fourth embodiments.

As already described, the low dielectric constant insulating film used for suppressing the signal delay includes many holes and has high hygroscopicity. Therefore, oxidizing species such as H ₂ O contained in the low dielectric constant insulating film are released by heating at the time of forming the metal film. In order to reduce the influence of the released gas on the metal film, etc., the degassing treatment is performed before the metal film is formed. However, the amount of the released gas is increasing as the dielectric constant of the insulating film is reduced. The heating time for is getting longer. The heating time can be shortened by increasing the heating temperature in the degassing treatment. However, if the substrate is heated at a high temperature before forming a metal film such as a barrier metal film, there is a problem that voids are generated in the Cu wiring formed on the substrate. On the other hand, if the degassing treatment from the insulating film is performed at a low temperature, it takes time and the throughput is lowered.

  As already shown in the first to fourth embodiments, it is important to control the degassing from the low dielectric constant insulating film. In order to perform sufficient control, the throughput is improved or the degassing is performed. It is necessary to increase the efficiency as in high-temperature heating.

  An example of improving the throughput in the degassing process is shown below. With the semiconductor manufacturing apparatus shown in FIGS. 38A and 38B, the throughput of the degassing process performed before forming the metal film can be increased.

  The semiconductor manufacturing apparatus shown in FIG. 38 (a) includes a support 150a that can be moved up and down and a pickup mechanism 230 that can be rotated, to which a plurality of hot plates 210a to 210j are connected. A lift pin 240 is attached to the pickup mechanism 230. The hot plates 210a to 210j have holes through which the lift pins 240 pass. The substrates 10 can be arranged on the hot plates 210a to 210j, respectively. Hereinafter, a method of arranging the substrate 10 on the hot plate 210a will be described with reference to FIG. FIG. 38B is a top view of the hot plate 210a portion of the semiconductor manufacturing apparatus.

  (A) As shown in FIG. 38B, the pickup mechanism 230 moves to the position A below the hot plate 210a. Then, the vertical position of the support 150a is adjusted so that the tip of the lift pin 240 protrudes from the upper surface of the hot plate 210a through the hole formed in the hot plate 210a.

  (B) The substrate 10 is transferred by a transfer robot hand 220 from a transfer chamber (not shown). The conveyed substrate 10 is placed on the tip of the lift pin 240.

  (C) Next, when the support 150a moves upward, the tip of the lift pin 240 becomes lower than the upper surface of the hot plate 210a, and the substrate 10 is placed on the hot plate 210a.

  (D) Next, the pickup mechanism 230 rotates and moves to the position B.

  Thereafter, the support 150a moves upward, and the substrate is placed on the hot plates 210b to 210j in the same manner as described above. Further, after the processing is completed, the substrate 10 is transferred to the transfer chamber by performing the reverse operation to the method described above. If there is a substrate to be processed next, it is not necessary to increase the number of hot plates 210a to 210j more than necessary by repeatedly placing the substrates on the hot plates 210a to 210j that have been processed and taken out. . FIG. 38A shows an example in which the number of hot plates is 10, but it goes without saying that the number of hot plates is not limited to 10.

  The semiconductor manufacturing apparatus shown in FIG. 38A described above can be used as one of a plurality of chambers connected to the cluster tool. Then, before or after the process performed by the semiconductor manufacturing apparatus shown in FIG. 38A, it is possible to perform another process continuously in a vacuum in another chamber connected to the transfer chamber. For example, after removing and reducing the oxidized species contained in the insulating film by the semiconductor manufacturing apparatus shown in FIG. 38A, the substrate is moved to another chamber through the transfer chamber to remove the oxide film on the Cu wiring surface. Process. Next, a continuous process is possible in which a barrier metal film is formed in a separate chamber and a Cu film is formed in a separate chamber.

  By using the semiconductor manufacturing apparatus shown in FIG. 38A, the throughput of the degassing process can be increased. In the case of a semiconductor device manufacturing method in which a long time is required for degassing processing and the process can proceed in units of a plurality of substrates, only one substrate can be degassed in one chamber of the cluster tool. In the case of no semiconductor manufacturing apparatus, the degassing time is very long. For example, consider a case where 10 minutes are required for degassing the insulating film. In a process performed in a separate chamber, a process time of a process (hereinafter referred to as a “second process process”) having a long process time after the degassing process process is set to 72 seconds. In that case, the difference in processing time between the deprocessing step and the second processing step is a time for the substrate to wait for the completion of the degassing processing in another chamber. Assuming that the time required for transfer between the chambers is 20 seconds, it takes about 4 hours and 36 minutes to continuously degas the 25 substrates. If the degassing processing of a plurality of substrates is performed in parallel in one chamber using the semiconductor manufacturing apparatus shown in FIG. 38, the processing time can be greatly shortened. In addition, the apparatus space of the entire apparatus can be reduced compared to installing a plurality of chambers that can process only one substrate.

  It is also industrially required to minimize the apparatus cost by minimizing the number of hot plates 210a to 210j included in the semiconductor manufacturing apparatus shown in FIG. For example, the number of hot plates 210a to 210j is the number obtained by dividing the time required for the degassing process by the processing time of the second processing step and rounding up the decimal point of the obtained value. If the number of hot plates obtained by the above calculation is prepared, it is possible to minimize the time during which other processes stop after waiting for the completion of the degassing process. That is, the number of hot plates in the semiconductor manufacturing apparatus shown in FIG. 38 is the number of integers obtained by rounding up the decimal point of t1 / t2, where t1 is the degassing time and t2 is the second processing time. do it. When calculated in the above example, 600 seconds ÷ 72 seconds = 8.3, so the number of hot plates may be nine. In that case, the processing time when 25 substrates are degassed as a processing unit is about 1 hour 6 minutes.

In order to increase the degassing efficiency by increasing the heating rate of the substrate 10 disposed on the hot plates 210a to 210j, the temperature may be controlled by attaching an electrostatic chuck mechanism to the hot plates 210a to 210j. Further, in order to improve heat conduction, He gas, H ₂ gas, Ar gas, N ₂ gas, or the like may be introduced to increase the rate of temperature increase or temperature uniformity of the substrate 10. Alternatively, the substrate 10 may be heated by halogen lamp irradiation.

Further, by introducing a reducing gas such as H ₂ or a radical gas activated by a microwave discharge or the like into a chamber for degassing treatment, the oxide film on the surface of the Cu wiring can be reduced and removed. As a result, the reduction process performed in another chamber can be reduced. However, during the degassing process for a long time, the substrate 10 is transferred for each of the hot plates 210a to 210j, so that the partition valve with the transfer chamber is opened and closed. Accordingly, problems such as reduction gas such as H ₂ flowing into the transfer chamber and lowering the degree of vacuum of the transfer chamber, or mixing of the reduction gas into another chamber through the transfer chamber and contaminating the other chamber occur. Therefore, when introducing the reducing gas, the introduction of the reducing gas may be stopped when the partition valve is opened for transporting the substrate. Even when no reducing gas or the like is introduced, the degree of vacuum in the degassing chamber is lowered by the gas released from the substrate or the gas introduced for heat conduction. Therefore, problems such as gas mixing into and contamination of another chamber through the transfer chamber occur when the partition valve is opened and closed. In that case, the entire cluster tool may be controlled so that the partition valve with another chamber is not opened when the partition valve is opened or closed.

  In FIG. 38, the semiconductor manufacturing apparatus in which a plurality of hot plates 210a to 210j are arranged one above the other has been described. In addition, the semiconductor manufacturing apparatus illustrated in FIG. 39 can be applied to a degassing process. The semiconductor manufacturing apparatus shown in FIG. 39 has a structure in which a plurality of hot plates 211a to 211f are installed in a radial pattern on a rotatable support 150b. The hot plates 211a to 211f have lift pins 241 that can move up and down. Substrates can be arranged on the hot plates 211a to 211f, respectively. FIG. 39 shows an example in which the substrates 10a and 10b are respectively arranged on the hot plates 211a to 211b. As an example of the operation of the semiconductor manufacturing apparatus shown in FIG. 39, a case where the substrate 10c is arranged on the hot plate 211 will be described below. The substrate 10c transferred from the transfer chamber (not shown) by the transfer robot hand 220a is placed on the tip of the lift pin 241 protruding from the upper surface of the hot plate 211c. Thereafter, the lift pins 241 are lowered and the substrate 10c is placed on the hot plate 211c.

  Thereafter, the support 150b is rotated to sequentially place the substrates on the hot plates 211d to 211f. Further, after the processing is completed, the substrate is unloaded by performing the reverse operation of the method described above. If there is a substrate to be processed next, it is not necessary to increase the number of hot plates 211a to 211f more than necessary by repeatedly arranging the substrates on the hot plates 211a to 211f from which the substrates have been unloaded. Further, if the hot plates 211a to 211f are each configured to be partitioned in vacuum, contamination of other substrates due to degassing generated during degassing processing of the respective substrates disposed on the hot plates 211a to 211f is avoided. And contamination due to degassing of the transfer chamber can be avoided. As shown in FIG. 39, by opening and closing the slit valve 310, contamination of the transfer chamber 300 due to degassing can be prevented. The slit valve 310 is opened when the substrate is transferred from the transfer chamber 300 to the hot plates 211a to 211f, and is closed during the degassing process.

Further, if the hot plates 211a to 211f are partitioned in a vacuum state, when H ₂ gas or the like is introduced for the oxide reduction process performed on the substrate on one hot plate, the other is caused by H ₂ gas or the like. Contamination of the substrate and the transfer chamber on the hot plate can be avoided. The semiconductor manufacturing apparatus shown in FIG. 39 can be used as one chamber connected to the cluster tool, similarly to the semiconductor manufacturing apparatus shown in FIG. FIG. 39 shows an example in which the number of hot plates is six, but the number of hot plates is not limited to six.

  38A and 39, an example of a semiconductor manufacturing apparatus provided with a plurality of hot plates has been described. Hereinafter, an example of a semiconductor manufacturing apparatus capable of heat-treating a plurality of substrates with one heating mechanism will be described. The semiconductor manufacturing apparatus shown in FIG. 40A includes a chamber 100c, a quartz tube 400 in which a plurality of quartz boards 403 that respectively support a plurality of substrates 10 are arranged, and a heater that surrounds the periphery of the quartz tube 400 in a tubular shape. 401 and a high frequency application coil 402 are provided. Unlike the case where a plurality of hot plates are used, when the semiconductor manufacturing apparatus shown in FIG. 40A is used, a plurality of substrates are collectively degassed using one heater 401. However, even when a plurality of substrates are processed in a lump, the substrate may be transferred for each substrate as in the case of using a plurality of hot plates. For example, as shown in FIG. 40B, the substrate 10 can be transferred using the transfer robot hand 220b. However, when the substrate 10 is transferred using the transfer robot hand 220b, the quartz tube 400 has an opening, and a part of the quartz tube 400 serves as the heater 401 as shown in FIG. Not surrounded. Thus, when there is a part which is not surrounded by the heater 401, the thermal uniformity in the quartz tube 400 is lowered. For this reason, it is necessary to devise a method for maintaining the temperature uniformity of the in-plane temperature of the substrate 10 by rotating the substrate 10 or the like. Moreover, the uniformity of the in-plane temperature of the substrate 10 can be improved by setting the gas pressure during the degassing process to several hundred Pa or more.

  Next, an example of a semiconductor manufacturing apparatus capable of performing degassing processing with high efficiency by a degassing processing method other than a heating method using a hot plate or a heater will be described. In the following, a semiconductor manufacturing apparatus that efficiently releases water molecules contained in an insulating film using μ waves will be described. A water molecule has a structure in which two hydrogen atoms are bound to one oxygen atom. When the oxygen atom and the hydrogen atom are combined, the electrons in the hydrogen atom are displaced in the direction of the oxygen atom, so that the polarity near the bond is positive for the oxygen atom and negative for the hydrogen atom. As a result, the water molecule remains neutral as a whole, while having a positive polarity on the hydrogen atom side and a negative polarity on the oxygen atom side. On the other hand, in general, radio waves travel through space while changing polarity (vibrating) alternately in the positive and negative directions. Therefore, the fact that the μ wave hits the bonding portion between oxygen atoms and hydrogen atoms means that electrical energy in both positive and negative directions is alternately applied to the bonding portion. At that time, assuming that energy in the positive direction is first applied to the water molecule bond, water molecules that have been in thermal motion in different directions until then will attract oxygen atoms with negative polarity to the direction of the μ wave. And change direction all at once. Next, when energy in the negative direction is applied to the bond, hydrogen atoms having a positive polarity are attracted this time, so the water molecules turn all at once again. By taking advantage of the characteristics of water molecules and μ waves described above, only water molecules can be released from the insulating film. That is, when the μ wave emitted from the radio wave oscillator is applied to the insulating film, the water molecules contained in the insulating film are heated (dielectric heating) by the movement of the water molecules. As a result, only water molecules can be released from the insulating film. Note that the μ wave irradiation is preferably performed in a vacuum. Furthermore, in order to prevent the possibility of arc discharge, it is preferable to carry out in a state where the metal film is not exposed. Parameters such as the power of the μ wave to be used are selected according to the insulating film being used.

Further, the chamber for performing the degassing treatment has a problem that a by-product containing a degassed gas component adheres to the chamber and causes dust, or temperature control during the heat treatment becomes difficult. The gas released from the insulating film during the degassing treatment is often a gas containing C, F, etc. generated in the process using the RIE method in addition to the oxidizing species such as H ₂ O. In order to clean the by-product adhered in the chamber, it takes time to perform maintenance by opening the chamber to the atmosphere, resulting in a decrease in productivity. Therefore, the chamber cleaning can be completed in a short time if the plasma is removed using a gas containing oxygen or hydrogen, or radicals. That is, it is desirable that the chamber for performing the degassing process has a cleaning mechanism. For example, as shown in FIG. 40A, if a high-frequency application coil 402 capable of applying high-frequency power is provided on the outer periphery of the quartz tube 400, quartz can be obtained by applying high-frequency power while introducing oxygen and hydrogen. Plasma can be generated in the tube 400. Therefore, it is not necessary to perform maintenance that involves opening to the atmosphere.

  For an insulating film with high hygroscopicity, it is also effective to replace the adsorbed water in the insulating film with an organic solution having a high vapor pressure and dry it. For example, water molecules contained in the insulating film are reduced by dropping methanol, ethanol, or the like onto the substrate, washing, and drying. By performing the degassing process after this, high efficiency of the degassing process can be realized.

  Below, the method of performing EB irradiation and UV light irradiation as an efficient surface modification method is demonstrated. The chamber for performing EB irradiation and UV light irradiation is connected to a transfer chamber provided with a substrate transfer mechanism, and is vacuumed in another chamber connected to the transfer chamber before or after the EB irradiation and UV light irradiation processing. It is also possible to perform separate processing continuously. For example, after removing or reducing the adsorbed gas adsorbed on the interlayer insulating film in the chamber for EB irradiation and UV light irradiation, the substrate is moved into another chamber through the transfer chamber, and the surface of the lower Cu wiring The oxide film is removed. Next, a continuous process in which a barrier metal film is formed in another chamber and a Cu film is further formed in another chamber is possible.

  FIG. 41A shows a cross section of a structure of a semiconductor manufacturing apparatus having an EB irradiation function capable of continuously transferring a substrate to a chamber for forming a barrier metal film or a Cu film. The semiconductor manufacturing apparatus shown in FIG. 41A includes a hot plate 210 on which the substrate 10 is disposed, and a chamber 100d including an electron beam generation source 500 that irradiates the substrate 10 with EB.

  FIG. 41 (b) shows an example of a semiconductor manufacturing apparatus capable of UV light irradiation. The semiconductor manufacturing apparatus shown in FIG. 41B is a UV light generation source that irradiates the substrate 10 with UV light through a chamber 100d including a hot plate 210 on which the substrate 10 is disposed, and a light transmission window 610 provided on the upper surface of the chamber 100d. 600.

As described in the fourth embodiment, the terminal group of the outermost surface atom varies depending on the type of insulating film. For example, when it is terminated with a CH ₃ group, it exhibits hydrophobicity, and when it is terminated with an OH group, it exhibits a difference in adsorption properties such as hydrophilicity. Therefore, when EB irradiation or UV irradiation is performed before barrier metal formation, it is possible to remove CH ₃ groups on the surface. Thereby, coupling | bonding with a barrier metal becomes easy and adhesiveness can be improved. Moreover, in an insulating film incompletely polymerized, polymerization can be ensured, and unnecessary gas components can be removed from the film.

  FIG. 42A and FIG. 42B show a process flow when surface modification processing such as EB irradiation and UV light irradiation and degassing processing are performed. The EB irradiation and UV light irradiation processes are the same processes as the insulating film curing process. Therefore, if the EB irradiation and UV light irradiation processes are performed a plurality of times, the curing process may proceed more than necessary, and the dielectric constant of the insulating film may increase. Therefore, as shown in FIG. 42A, it is preferable to divide the energy and irradiation time required for the insulating film cure after the step of forming the insulating film and before the step of forming the barrier metal film. Alternatively, as shown in FIG. 42B, the process flow may be changed so that the curing process of the insulating film also serves as the acceleration process of the degassing process before forming the barrier metal film.

As described above, according to the semiconductor manufacturing apparatus according to the sixth embodiment of the present invention, when the degassing process of the low dielectric constant insulating film having high hygroscopicity takes a long time, the throughput is improved. The reduction can be suppressed, and a highly efficient degassing process can be performed.
(Other embodiments)
As described above, the present invention has been described according to the first to sixth embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the description of the first to sixth embodiments already described, the case where Ti and Ti nitride, Al and Al oxide are formed has been described as an example, but the following applications are naturally possible. For example, as a metal film between the wiring layer and the insulating film, tantalum (Ta), tungsten (W), hafnium (Hf), zinc (Zn), magnesium (Mg), zirconium (Zr), vanadium (V), etc. But it is possible. In particular, it has been described in the embodiment that Mg, Zr, V, etc. are promising among IIa, IIIa, IVa, and Va group metals.

  Furthermore, in the fourth and fifth embodiments, if the source gas and other introduced gas are changed, silicon (Si), Ta, W, Hf, Zn, ruthenium (Ru), etc., or oxides thereof, It can also be applied to nitride film formation.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 1). FIG. 6 is a process cross-sectional view for explaining the manufacturing method of the semiconductor device according to the first embodiment of the present invention (No. 2). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 3). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 4). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 5). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 6). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 7). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 8). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 9). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 10). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 11). It is process sectional drawing for demonstrating the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention (the 12). It is a schematic diagram which shows the example of the semiconductor manufacturing apparatus which performs the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. It is a sectional view showing the structure of an oxide film formed by a conventional method for manufacturing a semiconductor device. 1 is a cross-sectional structure diagram illustrating a structure of an oxide film formed by a method for manufacturing a semiconductor device according to a first embodiment of the present invention. FIG. 16A shows a result of analyzing a sample after heat treatment at 370 ° C. for 60 minutes by an X-ray diffraction method. FIG. 16A is a graph showing an analysis result of a sample manufactured using a conventional technique, and FIG. FIG. 16C is a graph showing an analysis result of a sample manufactured using the method for manufacturing a semiconductor device according to the first embodiment at a temperature of 25 ° C. FIG. 16C shows the first embodiment at a stage temperature of −20 ° C. The graph which shows the analysis result of the sample manufactured using the manufacturing method of the semiconductor device which concerns, FIG.16 (d) is a schematic diagram which shows the structure of the sample used for the analysis. It is a graph which shows the EELS analysis result of the titanium oxide film each manufactured using the manufacturing method and related technique of the semiconductor device which concern on 1st Embodiment. 1 is a structural cross-sectional view showing an example of a semiconductor device manufactured by using the method for manufacturing a semiconductor device according to the first embodiment of the present invention. It is a table | surface which shows the result of the secondary ion mass spectrometry (SIMS) of the wiring manufactured using the manufacturing method of the semiconductor device which concerns on 1st Embodiment. It is a graph which shows the ratio of the resistivity after annealing with respect to the resistivity before annealing of the wiring manufactured using the manufacturing method of the semiconductor device which concerns on 1st Embodiment. It is a graph which shows the molecular density of a Ti film | membrane and a TiOx film | membrane. FIG. 22A is a structural cross-sectional view showing an example of a Cu seed film formed by the method of manufacturing a semiconductor device according to the third embodiment of the present invention, and FIG. 22A is an example of forming a Cu seed film by ionization sputtering; 22B shows an example of Cu seed film formation by CVD (part 1), and FIG. 22C shows an example of Cu seed film formation by CVD (part 2). FIG. 23A is a cross-sectional structure diagram showing a structure of a wiring layer formed by a semiconductor device manufacturing method according to a comparative example (part 1) of the third embodiment of the present invention, and FIG. FIG. 23B is a cross-sectional structure diagram after the process involving heating. FIG. 24A is another cross-sectional structure diagram showing the structure of a wiring layer formed by the method of manufacturing a semiconductor device according to the comparative example (No. 2) of the third embodiment of the present invention. FIG. FIG. 24B is a cross-sectional structure diagram before the process, and FIG. 24B is a cross-sectional structure diagram after the process with heating. FIG. 25A is a cross-sectional structure diagram showing a structure of a wiring layer formed by a method for manufacturing a semiconductor device according to a third embodiment of the present invention, and FIG. 25A is a cross-sectional structure diagram before a process involving heating; FIG. 4B is a cross-sectional structure diagram after a process involving heating. It is a typical flowchart which shows the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention. It is a process flow figure explaining the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention (the 1). It is a process flowchart explaining the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention (the 2). It is a process flow figure explaining the manufacturing method of the semiconductor device concerning a 4th embodiment of the present invention (the 3). It is a process flow figure explaining the manufacturing method of the semiconductor device concerning a 4th embodiment of the present invention (the 4). It is a schematic diagram for demonstrating the effect of the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention. It is a typical flowchart which shows the manufacturing method of the conventional semiconductor device. It is a sectional view showing the structure of an oxide film formed by a conventional method for manufacturing a semiconductor device. It is sectional structure drawing which shows the structure of the oxide film formed by the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention. It is a process flow figure explaining a manufacturing method of a semiconductor device concerning a 5th embodiment of the present invention. It is sectional drawing which shows the structure of the Al oxide film formed by the manufacturing method of the conventional semiconductor device. It is a cross-section figure showing the structure of the Al oxide film formed using the manufacturing method of the semiconductor device concerning a 5th embodiment of the present invention. It is a schematic diagram which shows the structure of the semiconductor manufacturing apparatus based on the 6th Embodiment of this invention, Fig.38 (a) is sectional drawing, FIG.38 (b) is a top view. It is a schematic diagram which shows the other structure of the semiconductor manufacturing apparatus based on the 6th Embodiment of this invention. FIG. 40 is a schematic view showing still another structure of the semiconductor manufacturing apparatus according to the sixth embodiment of the present invention, FIG. 40 (a) is a sectional view, and FIG. 40 (b) is a top view. FIG. 41A is a schematic diagram illustrating a structure of a semiconductor manufacturing apparatus according to a sixth embodiment of the present invention, FIG. 41A is a schematic diagram of a semiconductor manufacturing apparatus that performs EB irradiation, and FIG. 41B is a UV light irradiation. It is a schematic diagram of the semiconductor manufacturing apparatus to perform. FIG. 42 is a process flow diagram for explaining a curing process of an insulating film using the semiconductor manufacturing apparatus shown in FIG. 41, and FIG. 42 (a) is a process flowchart in the case where the curing process is divided into two, and FIG. b) is a process flow diagram when the curing process is performed once.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Substrate 20 ... Insulating film 30 ... Metal film 35 ... Titanium oxide film 36 ... Tantalum film 50 ... Interlayer insulating film 70 ... Second wiring layer 71 ... Second Cu seed film 200 ... Recess

Claims (4)

A step of releasing at a first substrate temperature so as to leave a part of the oxidized species in the insulating film having a recess formed on the surface and the surface of the insulating film;
A barrier metal film made of metal is formed on the insulating film at a second substrate temperature that is lower than the first substrate temperature and does not release oxidizing species from the insulating film in a continuous vacuum with the step of releasing the oxidizing species. Forming, and
Forming a Cu wiring metal film on the barrier metal film;
After formation of the barrier metal film, by the oxidation species is left in the insulating film, so that the oxygen concentration of the barrier metal film, the insulating film side becomes higher the Cu wiring metal film side lower concentration gradient, the barrier A step of oxidizing the metal film ,
The method of manufacturing a semiconductor device , wherein the step of oxidizing the barrier metal film includes a step of heating the barrier metal film at a temperature higher than the first substrate temperature . 2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of forming a compound of the metal and Cu at an interface between the barrier metal film made of the metal and the Cu wiring metal film. The step of forming the Cu interconnect metal film on the barrier metal film, on the barrier metal film, the step of forming the Cu interconnect metal film, so that the state in which no part of at least the recess is filled Including
Said barrier process of heating metal film using the first temperature higher than the temperature of the substrate, method of manufacturing a semiconductor device according to claim 1, characterized in that it comprises the step of heating the substrate in the state. The method for manufacturing a semiconductor device according to claim 1, wherein the barrier metal film is made of Ti.

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