JP2010010626A - Manufacturing apparatus of semiconductor device and manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of a semiconductor device for improving the reliability of the semiconductor device by improving the oxidation resistance of a zirconium boronitride film in a multilayer interconnection structure, and to provide a manufacturing method of the semiconductor device. <P>SOLUTION: The manufacturing apparatus of the semiconductor device includes: a film-forming chamber 31S for storing a substrate in a heated state that an insulating film and a metal film surrounded by the insulating film are exposed; and a film-forming section for forming the zirconium boronitride film on the surface of the substrate S under heating by supplying Zr(BH<SB>4</SB>)<SB>4</SB>and excited nitrogen to the film-forming chamber 31S. The film-forming section reduces the amount of the supply of excited nitrogen as the film-formation time passes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method using a zirconium boronitride film.

  In the multilayer wiring technology in a semiconductor device, the copper wiring technology for ensuring the resistance of electromicronation becomes indispensable with the progress of miniaturization and multilayering of the semiconductor device. In this copper wiring technology, a trench is formed in an interlayer insulating film, copper (Cu) as a wiring material is filled in the trench, and a metal cap film is formed thereon as a protective film. When the aspect ratio becomes extremely high, it becomes difficult to clean the bottom of the trench, and as a result, the contact resistance may increase between the copper wiring and the underlying wiring.

In order to solve this problem, Patent Document 1 proposes zirconium boride or zirconium boronitride as a constituent material of the metal cap film, and laminates these zirconium compounds on the base film to increase the specific resistivity of the zirconium compound. Base dependency, so-called resistance selectivity, is used. In other words, one metal cap film made of a zirconium compound functions as a cap film having conductivity on the copper wiring, and functions as a cap film having insulation properties on the interlayer insulating film. According to this, since the bottom of the trench is made of a conductive zirconium compound having excellent oxidation resistance, even if there is a remaining film of the metal cap film at the bottom of the trench after the cleaning process, The contact resistance with the underlying wiring can be maintained at a good level.
JP 2003-17496 A

  However, even though the zirconium compound has resistance selectivity, the surface of the metal cap film is oxidized by a reaction with an oxidation source existing in a film forming atmosphere or a transport environment. In order to maintain the contact resistance between the wirings at a good level, it is desirable to minimize the thickness of the oxide layer. In particular, this kind of oxidation resistance is obtained in a metal cap film having a film thickness of less than 30 nm. Is essential.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a semiconductor device manufacturing apparatus and semiconductor device in which the reliability of a semiconductor device is improved by improving the oxidation resistance of a zirconium boronitride film in a multilayer wiring structure It aims at providing the manufacturing method of.

  In examining the reaction system of the zirconium boronitride film, the present inventor, when the nitrogen concentration in the film becomes high, the oxidation selectivity of the zirconium boronitride film is lowered while the resistance selectivity is improved. It has been found that when the nitrogen concentration in the film is lowered, the resistance selectivity of the zirconium boronitride film is lowered while the oxidation resistance is improved. That is, the present inventor has found that the resistance selectivity of the zirconium boronitride film and the oxidation resistance of the zirconium boronitride film have a contradictory relationship with respect to the nitrogen concentration in the film.

The apparatus for manufacturing a semiconductor device according to claim 1 is excited with a vacuum chamber that accommodates a heated substrate in which an insulating film and a metal film surrounded by the insulating film are exposed, and Zr (BH ₄ ) ₄ . An apparatus for manufacturing a semiconductor device, comprising: a film forming unit for supplying nitrogen to the vacuum chamber and forming a zirconium boronitride film on a heated substrate surface, wherein the film forming unit has a film forming time The gist is to reduce the supply amount of the excited nitrogen as time passes.

  According to the semiconductor device manufacturing apparatus of the first aspect, the insulating film in the zirconium boronitride film and the lower layer portion (hereinafter referred to as a bulk region) on the metal film side can be formed under a relatively high nitrogen concentration. Thus, resistance selectivity can be expressed in the zirconium boronitride film by increasing the nitrogen content in the bulk region. Since the surface layer portion of the zirconium boronitride film can be formed under a relatively low nitrogen concentration, the oxidation resistance to the bulk region can be improved by the surface layer portion. Therefore, the oxidation resistance of the zirconium boronitride film in the multilayer wiring structure can be improved, and as a result, the reliability of the semiconductor device can be improved.

  The semiconductor device manufacturing apparatus according to claim 2 is the semiconductor device manufacturing apparatus according to claim 1, wherein the film forming unit sets the supply amount of the excited nitrogen to a first value as a bulk region. A first zirconium boronitride film is formed, and the supply amount of the excited nitrogen is switched from the first value to a second value lower than the first value, thereby forming a second boronitride as a surface layer portion. The gist is to form a zirconium film and coat the first zirconium boronitride film with the second zirconium boronitride film which is thinner than the first zirconium boronitride film.

  According to the semiconductor device manufacturing apparatus of the second aspect, the high nitrogen concentration in the bulk region can be realized by the first value, and the low nitrogen concentration in the surface layer portion can be realized by the second value. Therefore, the oxidation resistance of the zirconium boronitride film can be improved only by switching the excited nitrogen from the first value to the second value, and therefore the reliability of the semiconductor device is improved under a simple configuration. Can be made.

  A semiconductor device manufacturing apparatus according to claim 3 is the semiconductor device manufacturing apparatus according to claim 2, wherein the film forming unit controls a flow rate of nitrogen gas to a tube connected to the vacuum chamber. And a microwave power source for irradiating microwaves into the tube, and when forming the zirconium boronitride film, the output from the microwave power source is maintained and the flow controller is driven. Thus, the gist of the present invention is to switch the flow rate of the nitrogen gas from the first flow rate to the second flow rate and switch the supply amount of the excited nitrogen from the first value to the second value.

  According to the semiconductor device manufacturing apparatus of the third aspect, the oxidation resistance of the zirconium boronitride film can be improved only by switching the flow rate of the nitrogen gas from the first flow rate to the second flow rate using the flow rate controller. it can. Therefore, the reliability of the semiconductor device can be improved with a simpler configuration.

The method of manufacturing a semiconductor device according to claim 4, a metal film is surrounded by the insulating film and the insulating film by heating the substrate to expose, supplying the nitrogen excited with Zr (BH _{4) 4} to the substrate A method of manufacturing a semiconductor device comprising a step of forming a zirconium boronitride film on a heated substrate surface, wherein the step of forming the zirconium boronitride film is performed as the film formation time elapses. The gist is to reduce the supply amount of the excited nitrogen.

  According to the method for manufacturing a semiconductor device according to claim 4, since the bulk region of the boronitride film can be formed under a relatively high nitrogen concentration, the zirconium boronitride film can be formed by increasing the nitrogen content of the bulk region. Resistance selectivity can be expressed. Since the surface layer portion of the zirconium boronitride film can be formed under a relatively low nitrogen concentration, the oxidation resistance to the bulk region can be improved by the surface layer portion. Therefore, the oxidation resistance of the zirconium boronitride film in the multilayer wiring structure can be improved, and as a result, the reliability of the semiconductor device can be improved.

  The method for manufacturing a semiconductor device according to claim 5 is the method for manufacturing a semiconductor device according to claim 4, wherein the step of forming the zirconium boronitride film sets the supply amount of the excited nitrogen to a first value. A first zirconium boronitride film that is a bulk region is formed, and the supply amount of the excited nitrogen is switched from the first value to a second value that is lower than the first value. The second zirconia boronitride film is formed, and the first zirconia boronitride film is covered with the second zirconia boronitride film which is thinner than the first zirconia boronitride film.

  According to the semiconductor device manufacturing method of the fifth aspect, the high nitrogen concentration in the bulk region can be realized by the first value, and the low nitrogen concentration in the surface layer portion can be realized by the second value. Therefore, the oxidation resistance of the zirconium boronitride film can be improved only by switching the excited nitrogen from the first value to the second value, and therefore the reliability of the semiconductor device is improved under a simple configuration. Can be made.

  A method for manufacturing a semiconductor device according to a sixth aspect is the method for manufacturing a semiconductor device according to the fifth aspect, wherein the step of forming the zirconium boronitride film is performed on a nitrogen gas supplied from a flow rate controller. The excited nitrogen is generated by irradiating a wave to generate the excited nitrogen and switching the flow rate of the nitrogen gas from the first flow rate to the second flow rate while maintaining the output from the microwave power source. The gist is to switch from the first value to the second value.

  According to the method for manufacturing a semiconductor device described in claim 6, the oxidation resistance of the zirconium boronitride film can be improved only by switching the flow rate of nitrogen gas from the first flow rate to the second flow rate. Therefore, the reliability of the semiconductor device can be improved with a simpler configuration.

  A method of manufacturing a semiconductor device according to claim 7 is the method of manufacturing a semiconductor device according to claim 5 or 6, wherein the step of oxidizing the second zirconium boronitride film and the second zirconium boronitride film And laminating the other insulating film with a recess extending from the surface of the other insulating film to the metal film through the zirconium boronitride film and embedding the recess. The present invention includes a step of forming a wiring buried in the recess by laminating a metal film on the other insulating film and planarizing the metal film.

  According to the semiconductor device manufacturing method of the seventh aspect, since part or all of the zirconium boronitride film is removed between the metal film and the wiring, the contact resistance between the metal film and the wiring is reduced. The influence of the second zirconium boronitride film can be sufficiently suppressed. Therefore, good contact resistance can be obtained between the metal film and the wiring, and the reliability of the semiconductor device can be improved.

  As described above, according to the present invention, there are provided a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method in which the reliability of the semiconductor device is improved by improving the oxidation resistance of the zirconium boronitride film in the multilayer wiring structure. The purpose is to do.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. First, the semiconductor device 10 manufactured using the present invention will be described. FIG. 1 is a partial cross-sectional view showing a semiconductor device 10. The semiconductor device 10 is, for example, a memory including various RAMs and various ROMs, or a logic including an MPU and general-purpose logic.

[Semiconductor device 10]
In FIG. 1, a diffusion region S is formed on the surface (the upper surface in FIG. 1) of the substrate S included in the semiconductor device 10.
A first interlayer insulating film D1 is laminated so as to cover the MOS transistor Tr on a. A contact hole CH that penetrates to the diffusion region Sa is formed in the first interlayer insulating film D1, and a contact plug P is filled inside the contact hole CH.

  A second interlayer insulating film D2 and a first hard mask HM1 that covers the second interlayer insulating film D2 are sequentially stacked on the surface of the first interlayer insulating film D1. As the second interlayer insulating film D2, a porous low dielectric constant film made of a silicon oxide film or the like can be used. As the first hard mask HM1, a carbon-containing silicon-based insulating film such as silicon carbide or hydrocarbon silicon is used. Can be used. The second interlayer insulating film D2 and the first hard mask HM1 are formed with a recess (first trench TH1) extending upward from the contact hole CH. The entire inner surface of the first trench TH1 is covered with a first barrier film B1 having a high barrier property against copper atoms, and the first trench TH1 covered with the first barrier film B1 includes a wiring material. The first wiring M1 made of copper is filled. The upper surface of the first wiring M1 is covered with a first metal cap film MC1 made of zirconium boronitride that extends over the entire upper surface of the first hard mask HM1.

The first metal cap film MC1 includes a bulk region and a surface layer portion MC1s that is thinner than the bulk region. The bulk region has a specific resistance value according to the specific resistance value of the base by containing nitrogen at a higher concentration than the surface layer portion MC1s, so to say, has resistance selectivity. The bulk region is, for example, a conductive bulk region MC1c having a low specific resistance value of 5 to 8 [μΩ · cm] in a region on the surface of the first wiring M1 which is a conductor (a region indicated by dark dots in FIG. 1). And an insulating bulk region MC1d having a high specific resistance value of 10 ² [Ω · cm] or more in a region on the surface of the first hard mask HM1 which is an insulator (a region indicated by thin dots in FIG. 1). Become. The surface layer MC1s contains nitrogen at a lower concentration than the bulk region, and exhibits a common insulating property regardless of the specific resistance values of the base and the bulk region. For example, the surface layer MC1s has a high specific resistance of 10 ² [Ω · cm] or more on the surface of the first wiring M1 that is a conductor and on the surface of the first hard mask HM1 that is an insulator.

  A third interlayer insulating film D3, an etch stop film ES, a fourth interlayer insulating film D4, and a second hard mask HM2 are sequentially stacked on the surface of the first metal cap film MC1. As the third interlayer insulating film D3 and the fourth interlayer insulating film D4, a porous low dielectric constant film made of a silicon oxide film or the like can be used. As the etch stop film ES and the second hard mask HM2, silicon carbide, A carbon-containing silicon-based insulating film such as hydrocarbon silicon can be used. In the first metal cap film MC1, the third interlayer insulating film D3, and the etch stop film ES, a concave portion (via hole VH) extending upward from the first wiring M1 is formed to penetrate the fourth interlayer insulating film D4 and the second interlayer insulating film D4. A recess (second trench TH2) that extends upward from the via hole VH is formed through the hard mask HM2.

  The entire inner surfaces of the via hole VH and the second trench TH2 are covered with a second barrier film B2 having a high barrier property against copper atoms. The via hole VH covered with the second barrier film B2 is filled with a via wiring V1 made of copper as a wiring material, and the inside of the second trench TH2 covered with the second barrier film B2 is also the same. The second wiring M2 made of copper as the wiring material is filled. The upper surface of the second wiring M2 is covered with the second metal cap film MC2 made of zirconium boronitride over the entire upper surface of the second hard mask HM2.

  Like the first metal cap film MC1, the second metal cap film MC2 includes a bulk region and a surface layer portion thinner than the bulk region, and the bulk region has a specific resistance value corresponding to the specific resistance value of the base. Thus, the surface layer portion exhibits a common insulating property regardless of the specific resistance value of the base or bulk region.

[Film Forming Apparatus 20]
Next, a film forming apparatus 20 as a manufacturing apparatus for the semiconductor device 10 will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing the entire film forming apparatus 20, and FIG. 3 is a cross-sectional view showing the configuration of the film forming chamber 23. FIG. 4 is a block diagram showing an electrical configuration of the film forming chamber 23.

  In FIG. 2, the film forming apparatus 20 includes a load lock chamber 21, a core chamber 22 connected to the load lock chamber 21, and four film forming chambers 23 connected to the core chamber 22. The chamber 21 and each film forming chamber 23 communicate with each other via the core chamber 22 so that a common vacuum system can be formed.

  The load lock chamber 21 is a vacuum chamber that accommodates a plurality of substrates S, and carries each substrate S into the film forming apparatus 20 when the film forming process for the substrate S is started. Further, when the film forming process of the substrate S is completed, the load lock chamber 21 accommodates the substrate S after the film forming process, opens it to the atmosphere, and carries it out of the film forming apparatus 20. The core chamber 22 is a vacuum chamber in which the transfer robot 22 a is mounted. When starting the film formation process for the substrate S, the core chamber 22 is loaded from the load lock chamber 21 and unloaded to the film formation chamber 23. When the film forming process for the substrate S is completed, the core chamber 22 carries the substrate S in the film forming chamber 23 and carries it out to the load lock chamber 21.

  The film forming chamber 23 is a chamber for forming the zirconium boronitride film using a CVD method. When performing the film forming process, the substrate S is carried from the core chamber 22 and the zirconium boronitride film, A first metal cap film MC1 and a second metal cap film MC2 are formed.

  In FIG. 3, the film forming chamber 23 includes a chamber body 31 having an upper portion opened, and a chamber lid 32 disposed on the chamber body 31 so that the upper opening of the chamber body 31 can be opened and closed. The film forming chamber 23 has an internal space (hereinafter simply referred to as a film forming chamber 31S) surrounded by the chamber main body 31 and the chamber lid 32. The chamber body 31 is provided with a substrate stage 33 on which the substrate S is placed. The substrate stage 33 is a stage incorporating a resistance heater 33H, and when the substrate S is placed, the substrate S is heated to a predetermined temperature (200 ° C. to 240 ° C.). Below the substrate stage 33 is connected an elevating mechanism 34 that allows the substrate stage 33 to be moved up and down in the vertical direction so that the substrate S can be carried in and out. An exhaust pump 35 is connected to one side of the chamber body 31 via an exhaust port P1. The exhaust pump 35 is configured by various pumps such as a turbo molecular pump and a dry pump. When the film forming process is performed, the pressure in the film forming chamber 31S is reduced to a predetermined pressure (1 Pa to 1000 Pa).

Below the chamber lid 32, a shower head 36 having a plurality of first supply holes H1 and a plurality of second supply holes H2 independent of the first supply holes H1 is attached. Each first supply hole H1 supplies Zr (BH ₄ ) ₄ that is a raw material of the zirconium boronitride film to the film forming chamber 31S, and each second supply hole H2 supplies excited nitrogen or excited hydrogen. This is supplied to the film forming chamber 31S. More specifically, a raw material tank TK is connected to each first supply hole H1 via the inside of the chamber lid 32 and a raw material gas port P2, and the raw material tank TK is supplied with argon as a carrier gas. A flow controller MFC1 is connected. When the carrier gas from the flow rate controller MFC1 is supplied to the raw material tank TK, the raw material tank TK causes the Zr (BH ₄ ) ₄ to be contained to bubble and the Zr (BH ₄ ) ₄ together with the carrier gas to the raw material gas port P2. The Zr (BH ₄ ) ₄ and the carrier gas are supplied to the film forming chamber 31S from each first supply hole H1.

  A flow rate controller MFC2 and a flow rate controller MFC3 are connected to each second supply hole H2 via the inside of the chamber lid 32 and the excitation gas port P3. The flow rate controller MFC2 and the flow rate controller MFC3 adjust nitrogen gas and argon gas to predetermined flow rates, respectively, and lead them to the excitation gas port P3. Inside the chamber lid 32, between the excitation gas port P3 and each second supply hole H2, an irradiation tube 37 having heat resistance made of a quartz tube or an alumina tube is provided. A microwave source 38 driven by a microwave power source FG and a waveguide 39 connected to the microwave source 38 and extending to the irradiation tube 37 are disposed outside the irradiation tube 37 in the radial direction. The microwave source 38 is, for example, a microwave oscillator that generates a microwave of 2.45 GHz, that is, a magnetron. The microwave source 38 receives a driving power from the microwave power source FG and has a predetermined output range, for example, 0.01 kW to 3.0 kW. Output microwave in range. The waveguide 39 propagates the microwave generated by the microwave source 38 to the inside of the waveguide 39 and irradiates the inside of the irradiation tube 37. When the microwave source 38 oscillates the microwave, the waveguide 39 irradiates the gas passing through the irradiation tube 37 with the microwave to excite the gas.

  Between each second supply hole H2 and the irradiation tube 37, a mesh 32a that is grounded via a chamber lid 32 is disposed. When the microwave source 38 excites the gas in the irradiation tube 37, that is, when the microwave source 38 generates plasma in the irradiation tube 37, the mesh 32a causes ions in the plasma flowing from the irradiation tube 37 to the second supply holes H2. The component is neutralized, and the radical component and the neutralized gas component in the plasma are supplied from each second supply hole H2 to the film forming chamber 31S. As a result, the argon gas and nitrogen gas introduced from the source gas port P2 into the irradiation tube 37 are converted into plasma by the irradiation tube 37, and then the ion components are neutralized by the mesh 32a. Only the film forming chamber 31S is supplied.

  Next, the electrical configuration of the film forming apparatus 20 will be described. In FIG. 4, the control unit 41 causes the film forming apparatus 20 to execute various processing operations such as transport of the substrate S and the film forming process. The control unit 41 includes an arithmetic unit that executes various arithmetic processes, a storage unit 41A that stores various data and various programs, a timer 41B that measures the elapsed time of various processing steps, and the like. For example, the control unit 41 reads a film forming process program stored in the storage unit 41A, and executes the film forming process based on the time measured by the timer 41B and the film forming program.

  The control unit 41 is connected to an input / output unit 42 including various operation switches such as a start switch and a stop switch, and various display devices such as a liquid crystal display. The input / output unit 42 inputs various data used for each processing operation to the control unit 41, and outputs data related to the film forming process status in the film forming apparatus 20. For example, the input / output unit 42 inputs conditions necessary for the film formation process of the bulk region and conditions necessary for the film formation process of the surface layer part MC1s to the control unit 41 as the condition data Id. The control unit 41 receives the various condition data Id input from the input / output unit 42, generates various control signals according to the condition data Id, and sets the film formation conditions corresponding to the condition data Id. The film forming process is executed below.

  Examples of conditions necessary for the film forming process include a film forming time, a gas flow rate, a film forming pressure, a film forming temperature, and an output of the microwave power source FG. In the present embodiment, the nitrogen gas flow rate and film formation time required for film formation in the bulk region are referred to as a first step flow rate and a first step time, respectively. Further, the flow rate of nitrogen gas and the film formation time required for film formation on the cover part are referred to as a second step flow rate and a second step time, respectively. The first step flow rate is set to a value higher than the second step flow rate so that the nitrogen concentration in the bulk region is higher than the nitrogen concentration in the surface layer portion. Further, the first step time is set to a time sufficiently longer than the second step time so that the film thickness of the bulk region is thicker than the film thickness of the surface layer portion.

  The control unit 41 is connected to an exhaust system drive circuit 43 for driving the exhaust system, and outputs a drive signal corresponding to the exhaust system drive circuit 43 to the exhaust system drive circuit 43. The exhaust system drive circuit 43 drives the exhaust system such as the exhaust pump 35 in response to a drive signal from the control unit 41, thereby adjusting the inside of each chamber such as the film forming chamber 31S to a predetermined film forming pressure. To do.

  The control unit 41 is connected to a transport system drive circuit 44 for driving the transport system, and outputs a drive signal corresponding to the transport system drive circuit 44 to the transport system drive circuit 44. In response to the drive control signal from the control unit 41, the transport system drive circuit 44 drives the transport system such as the transport robot 22a, the elevating mechanism 34, and the resistance heater 33H mounted on the substrate stage 33. The substrate S is transported along a predetermined transport path and the temperature is adjusted to a predetermined film forming temperature.

  The control unit 41 is connected to a flow rate controller drive circuit 45 for driving the flow rate controllers MFC1 to MFC3, and outputs a drive signal corresponding to the flow rate controller drive circuit 45 to the flow rate controller drive circuit 45. The flow controller drive circuit 45 drives each of the flow controllers MFC1 to MFC3 in response to a drive signal from the controller 41, thereby selectively supplying a gas with a predetermined flow rate to the film forming chamber 31S.

  The control unit 41 is connected to a microwave power supply drive circuit 46 for driving the microwave power supply FG, and outputs a drive signal corresponding to the microwave power supply drive circuit 46 to the microwave power supply drive circuit 46. The microwave power supply drive circuit 46 drives the microwave power supply FG in response to the drive signal from the control unit 41, and thereby outputs a microwave with a predetermined output value.

[Method of Manufacturing Semiconductor Device 10]
Next, a method for manufacturing the semiconductor device 10 using the film forming apparatus 20 will be described. FIG. 5 is a process chart showing the manufacturing process of the semiconductor device 10, and FIG. 6 is a timing chart showing the operation of each part in the film forming apparatus 20. 7A to 7D are diagrams showing the relationship between the oxidation resistance on the surface of the zirconium boronitride film and the flow rate of nitrogen gas under the film forming conditions.

  First, the MOS transistor Tr, the first interlayer insulating film D1, and the contact plug P are formed on the substrate S using a known semiconductor device manufacturing technique, and then the second interlayer insulating film D2 is formed using a known damascene method. Then, the first wiring M1 made of the first hard mask HM1, the first barrier film B1, and the copper film is formed. Then, when the first wiring M1 is formed, the substrate S having the first wiring M1 is carried into the film forming apparatus 20, and the above-described formation is performed on the first hard mask HM1 and the first wiring M1 which are the surfaces of the substrate S. Film treatment is performed (see FIG. 5).

  In starting the film forming process, the control unit 41 of the film forming apparatus 20 first drives the exhaust pump 35 based on the various condition data Id from the input / output unit 42 to set the pressure in the film forming chamber 31S to the condition data Id. Continue to adjust the film forming pressure based on. When the pressure in the film forming chamber 31S is adjusted to the film forming pressure, the controller 41 drives the resistance heater 33H to change the temperature of the substrate stage 33 to the film forming temperature based on the condition data Id, as shown in FIG. For example, the temperature is adjusted to 220 ° C. Then, the control unit 41 drives the transfer robot 22a to place the substrate S on the substrate stage 33, and heats the substrate S to the film formation temperature.

Next, the control unit 41 starts a time counting operation using the timer 41B and drives the flow rate controller MFC2 to flow nitrogen gas at a flow rate corresponding to the film formation conditions in the bulk region, that is, nitrogen at the first step flow rate. Gas is introduced into the irradiation tube 37. Subsequently, the control unit 41 drives the microwave power source FG to generate nitrogen plasma inside the irradiation tube 37, and supplies nitrogen radicals extracted by the mesh 32 a to the surface of the substrate S. At this time, in order to stabilize the plasma state of nitrogen, the flow rate controller MFC3 may be driven to introduce a predetermined flow rate of argon gas into the irradiation tube 37.

When the supply of the nitrogen radical is started, the control unit 41 drives the flow rate controller MFC1 to introduce a carrier gas having a flow rate corresponding to the film formation conditions in the bulk region into the raw material tank TK, and the carrier gas and Zr (BH ₄ ). ₄ is supplied to the surface of the substrate S. Thus, excited nitrogen is supplied to the surface of the heated substrate S, and then Zr (BH ₄ ) ₄ is supplied. Therefore, the nitridation reaction of Zr (BH ₄ ) ₄ adsorbed on the substrate surface and heat The decomposition reaction proceeds as a surface reaction, and the film formation process of the zirconium boronitride film is started.

  When the formation of the zirconium boronitride film is started, the control unit 41 keeps talking about the bulk region (conductive bulk region MC1c, insulating bulk) until the elapsed time counted by the timer 41B reaches the first step time. The flow rate of the nitrogen gas is kept at the first step flow rate until the zirconium boronitride film which is the region MC1d) is formed. When the film formation time measured by the timer 41B reaches the first step time, the control unit 41 drives the flow rate controller MFC2 to switch the flow rate of nitrogen gas from the first step flow rate to the second step flow rate. The controller 41 controls the flow rate controller MFC2 until the elapsed time reaches the second step time, that is, until a zirconium boronitride film (hereinafter simply referred to as a surface layer precursor MC1b) that is a precursor film of the surface layer MC1s is formed. The nitrogen gas flow rate from is maintained at the second step flow rate.

  As a result, an atmosphere having a relatively high nitrogen concentration is formed in the preceding film-forming atmosphere, and the zirconium boronitride film in which the nitrogen concentration in the film is relatively high, that is, a bulk region (conductive bulk) Region MC1c and insulating bulk region MC1d) are formed. Next, an atmosphere having a relatively low nitrogen concentration is formed in the subsequent film formation atmosphere, and the zirconium boronitride film in which the nitrogen concentration in the film is relatively low, that is, the surface layer precursor MC1b is continuously formed by the film formation atmosphere. Formed. As a result, a zirconium boronitride film having a relatively high resistance selectivity and a relatively low oxidation resistance is obtained in the bulk region, while a relatively low resistance selectivity and a relative value are obtained in the surface layer precursor. Thus, a zirconium boronitride film having high oxidation resistance can be obtained. The oxidation related to the bulk region is suppressed by the high oxidation resistance of the surface layer precursor MC1b.

  On the other hand, the surface layer precursor MC1b exhibits relatively high oxidation resistance due to the low nitrogen concentration in the film, but exhibits high conductivity over the entire surface layer due to its composition approaching zirconium boride. End up. Therefore, when the film formation process of the surface layer precursor MC1b is completed, the surface layer precursor MC1b is subjected to an oxidation process for eliminating conductivity. As a result, the insulating surface layer MC1s is formed over the entire bulk region, and the conductive first metal cap film MC1 is formed only in the region whose base is the conductor. In order to oxidize the surface layer precursor MC1b, the surface layer precursor MC1b can be simply left in the atmosphere. However, the film forming apparatus 20 is provided with the chamber for the oxidation treatment, and the chamber is subjected to the oxidation treatment. May be executed.

  When the first metal cap film MC1 is formed, the third interlayer insulating film D3, the etch stop film ES, the fourth interlayer insulating film D4, and the second hard mask HM2 are sequentially stacked on the first metal cap film MC1. Subsequently, a second trench TH2 is formed in the second hard mask HM2 and the fourth interlayer insulating film D4 using a known dual damascene method, and an etch stop film ES, a third interlayer insulating film D3, and a first metal cap are formed. A via hole VH is formed in the film MC1. When the via hole VH and the second trench TH2 are formed, when the via hole VH and the second trench TH2 are formed, the second barrier film B2 that covers the inner surface of the via hole VH and the inner surface of the second trench TH2, and the via hole VH A second wiring M2 that fills the inside and the second trench TH2 is formed.

  At this time, the first metal cap film MC1 includes the surface layer portion MC1s that is an insulator. However, when the via hole VH is formed, the first metal cap film MC1 is etched, whereby the surface layer portion MC1s. Therefore, the conductivity between the second wiring M2 and the first wiring M1 is ensured. Furthermore, since the film thickness of the surface layer portion MC1s is sufficiently thinner than the conductive bulk region MC1c, there is a case where a residue of the first metal cap film MC1 exists when the first metal cap film MC1 is etched. Even in such a case, the contact resistance can be lowered by the amount that the conductivity of the residue can be obtained.

  When the second wiring M2 is formed, the substrate S having the second wiring M2 is carried into the film forming apparatus 20 again, and the second hard, which is the surface of the substrate S, is the same as the first metal cap film MC1. The film forming process is performed on the mask HM2 and the second wiring M2, and a second metal cap film MC2 including a bulk region and a surface layer portion is formed.

[Metal cap film formation conditions]
Next, the first step flow rate, the first step time, the second step flow rate, the second step time, or the so-called condition data Id used in the film forming process will be described with reference to FIGS. To do. The condition data Id is set as follows so that high oxidation resistance is obtained at the surface layer portion (surface layer precursor portion) of the metal cap film based on various tests performed in advance.

  FIGS. 7A to 7D show the results of Auger electron spectroscopy (AES) measurement after standing in the atmosphere for four types of zirconium boronitride films in which the flow rate of nitrogen gas, which is one of the film forming conditions, is changed. FIG. 7 (a) shows the AES measurement results for a zirconium boronitride film formed under the following film formation conditions using a silicon substrate. 7 (b) to 7 (d), each using a silicon substrate with a silicon oxide film, the flow rate of nitrogen gas is changed to 30 sccm, 50 sccm, and 100 sccm, and other conditions are the same as the following film formation conditions. The obtained AES measurement results are shown. In addition, the horizontal axis in FIGS. 7A to 7D represents the film thickness (converted film thickness) of the zirconium boronitride film converted using the sputtering amount at the time of AES measurement.

(Deposition conditions)
-Substrate temperature: 220 ° C
・ Zr (BH ₄ ) ₄ : 55 sccm
Carrier gas flow rate (MFC1): 100 sccm
Nitrogen gas flow rate (MFC2): 20 sccm
・ Microwave output: 44W
・ Processing pressure: 400Pa
As shown in FIGS. 7A to 7D, in the zirconium boronitride film, as the flow rate of nitrogen gas during film formation increases, the nitrogen concentration (“N” in FIG. 7: one point) An increase in the chain line is observed. For example, when the flow rate of nitrogen gas is 20 sccm, as shown in FIG. 7A, the nitrogen concentration in the film is less than 10%, but the flow rate of nitrogen gas during film formation is 30 sccm and 50 sccm. As shown in FIGS. 7B to 7D, the nitrogen concentration in the film increases to about 25%, about 33%, and about 38%. In addition, when 50 sccm and 100 sccm were used as the flow rate of nitrogen gas at the time of film formation, the above resistance selectivity was recognized as the nitrogen concentration in the film increased. On the other hand, 20 sccm and 30 sccm were observed. When used, conductivity on the insulator was expressed, and the above resistance selectivity was not sufficiently observed.

7A to 7D, in the zirconium boronitride film, as the equivalent film thickness increases, that is, as the depth from the film surface increases, the oxygen concentration ( In the figure, a decrease in “O” (solid line) is observed. An increase in the thickness from the film surface containing oxygen, that is, the thickness of the surface oxide layer in the zirconium boronitride film, is observed as the flow rate of nitrogen gas during film formation increases. For example, when the flow rate of nitrogen gas is 20 sccm, as shown in FIG. 7 (a), the zirconium boronitride film is left in the atmosphere until the depth from the film surface reaches 5.6 nm. Recognized, no oxidation is observed at depths above 5.6 nm. On the other hand, when the flow rate of nitrogen gas at the time of film formation is increased to 30 sccm, 50 sccm, and 100 sccm, the thickness of the surface oxide layer becomes 14.0 nm, 16. It increases to 8 nm and 16.8 nm.

  Therefore, the second step flow rate is set to the condition that the surface oxide layer is the thinnest regardless of the resistance selectivity, that is, 20 sccm, and the second step time is the surface oxide layer at the second step flow rate. The time corresponding to 5.6 nm, that is, 5.6 nm, is set. On the other hand, the first step flow rate is set such that the resistance selectivity is surely expressed regardless of the oxidation resistance, that is, 50 sccm or 100 sccm, and the first step time is a desired metal cap film. For example, a time corresponding to a film thickness (24.4 nm) obtained by removing the thickness of the surface oxide layer (5.6 nm) from 30 nm is set.

  Thereby, in the bulk region (conductive bulk region MC1c, insulating bulk region MC1d) of the metal cap film, relatively high resistance selectivity can be secured, and oxidation related to the bulk region has high acid resistance in the surface layer portion. Suppressed by chemical properties. Therefore, the metal cap film composed of the bulk region and the surface layer portion can improve the oxidation resistance without greatly impairing the resistance selectivity.

According to the said embodiment, there exist the following effects.
(1) In the above embodiment, the control unit 41 of the film forming apparatus 20 reduces the supply amount of excited nitrogen by lowering the supply amount of nitrogen gas as the deposition time of the zirconium boronitride film elapses. . Accordingly, since the bulk region of the zirconium boronitride film can be formed under a relatively high nitrogen concentration, resistance selectivity can be expressed in the zirconium boronitride film by increasing the nitrogen content of the bulk region. Since the surface layer portion of the zirconium boronitride film can be formed under a relatively low nitrogen concentration, the oxidation resistance to the bulk region can be improved by the surface layer portion. Therefore, in the multilayer wiring structure, the oxidation resistance of the zirconium boronitride film that is the metal cap film can be improved, and as a result, the reliability of the semiconductor device 10 can be improved.

  (2) In the above embodiment, the control unit 41 of the film forming apparatus 20 forms the bulk region by setting the flow rate of nitrogen gas to the first step flow rate, and changes the nitrogen gas flow rate from the first step flow rate to the first step flow rate. The surface layer part thinner than the bulk region is formed by switching to a lower second step flow rate. Therefore, the high nitrogen concentration in the bulk region can be realized by the first step flow rate, and the low nitrogen concentration in the surface layer portion can be realized by the second step flow rate. As a result, the oxidation resistance of the zirconium boronitride film can be improved only by switching the flow rate of nitrogen gas from the first step flow rate to the second step flow rate. Therefore, the reliability of the semiconductor device 10 can be improved under a simple configuration. Can be improved.

  (3) In the above embodiment, when the surface layer precursor MC1b is oxidized to form the surface layer MC1s and the via hole VH is formed, the metal cap film including the surface layer MC1s is etched. Accordingly, a part or all of the metal cap film is removed between the first wiring M1 and the second wiring M2, so that the contact resistance between the first wiring M1 and the second wiring M2 is reduced. The influence of the surface layer portion can be sufficiently suppressed. As a result, a good contact resistance can be obtained between the first wiring M1 and the second wiring M2, and as a result, the reliability of the semiconductor device 10 can be improved.

In addition, you may implement the said embodiment in the following aspects.
-In the said embodiment, it was set as the structure which switches the supply amount of the excited nitrogen with the flow volume of nitrogen gas. In addition to this, in reducing the supply amount of excited nitrogen as the deposition time elapses, the density of the nitrogen plasma in the irradiation tube 37 is switched by switching the output value from the microwave power source FG. The configuration may be such that the supply amount of the excited nitrogen is switched.

  In the above embodiment, the metal cap film composed of one bulk region and one surface layer portion has been described. However, the present invention is not limited to this, and the supply amount of excited nitrogen is lowered as the film formation time elapses. In this case, the metal cap film may be embodied as a film composed of a plurality of bulk regions or a plurality of surface layer portions.

  In the above embodiment, when forming the via hole VH, both the surface layer portion and the bulk region on the first wiring M1 are etched. However, the present invention is not limited to this, and in order to reduce the contact resistance between the first wiring M1 and the second wiring M2, only the surface layer portion may be etched.

  In the above embodiment, the surface layer part MC1s is oxidized by leaving the surface layer precursor part MC1b in the atmosphere. However, in order to eliminate the conductivity of the surface layer precursor part MC1b, the second interlayer insulation followed by the surface layer precursor part MC1b The structure oxidized by the film-forming process of the film | membrane D2 may be sufficient.

  In the above embodiment, the time corresponding to the thickness of the surface oxide layer is set as the second step time. In addition to this, in order to improve the oxidation resistance of the bulk region, a time corresponding to a film thickness thinner than the thickness of the surface oxide layer may be set as the second step time. In this configuration, the oxidation resistance of the bulk region can be improved as much as the surface layer is formed at the second step flow rate, and the thickness of the surface layer that is an insulator can be reduced. As a result, even when a residue of the metal cap film is generated at the bottom of the via hole VH, the contact resistance between the first wiring M1 and the second wiring M2 can be reliably reduced.

  In the above-described embodiment, the example in which the semiconductor device 10 has two layers of copper wiring has been described. However, the present invention is not limited thereto, and the semiconductor device 10 may be configured as long as the above-described zirconium boronitride film is used as a metal cap film. The number of copper wiring layers is not limited.

FIG. 6 is a partial cross-sectional view illustrating a semiconductor device. The figure which shows the whole film-forming apparatus. The fragmentary sectional view which shows the film-forming chamber. 1 is a block diagram illustrating an electrical configuration of a film forming apparatus. Process drawing which shows the manufacturing method of a semiconductor device. 6 is a time chart showing a method for manufacturing a semiconductor device. (A)-(d) is an AES measurement graph which shows the flow rate dependence of nitrogen gas with respect to the film thickness of a surface oxidation layer.

Explanation of symbols

MC1... First metal cap film constituting the zirconium boronitride film, MC1c... Conductive bulk region, MC1d... Insulating bulk region, MC1s. ... 1st wiring which comprises a metal film, M2 ... 2nd wiring which comprises a metal film, MFC1, MFC2, MFC3 ... Flow rate controller which comprises a film-forming part, FG ... Microwave power supply, 10 ... Semiconductor device, 20 ... Semiconductor A film forming apparatus as an apparatus for manufacturing the apparatus, 31S, a processing chamber constituting a vacuum chamber, 37, an irradiation tube, 38, a microwave source.

Claims (7)

A vacuum chamber that accommodates in a heated state the substrate from which the insulating film and the metal film surrounded by the insulating film are heated, Zr (BH ₄ ) ₄ and excited nitrogen are supplied to the vacuum chamber and heated. An apparatus for manufacturing a semiconductor device, comprising: a film forming unit that forms a zirconium boronitride film on a substrate surface;
The film forming unit includes:
An apparatus for manufacturing a semiconductor device, wherein the supply amount of the excited nitrogen is lowered as the film formation time elapses. A semiconductor device manufacturing apparatus according to claim 1,
The film forming unit includes:
A first zirconium boronitride film, which is a bulk region, is formed by setting the excited nitrogen supply amount to a first value, and the excited nitrogen supply amount is changed from the first value to the first value. A second zirconium boronitride film, which is a surface layer portion, is formed by switching to a lower second value, and the first zirconium boronitride film is covered with the second zirconium boronitride film that is thinner than the first zirconium boronitride film. An apparatus for manufacturing a semiconductor device. A semiconductor device manufacturing apparatus according to claim 2,
The film forming unit includes:
A flow rate controller for controlling the flow rate of nitrogen gas to a tube connected to the vacuum chamber;
A microwave power source for irradiating the tube with microwaves,
When forming the zirconium boronitride film, while maintaining the output from the microwave power source, the flow rate of the nitrogen gas is switched from the first flow rate to the second flow rate by driving the flow rate controller. An apparatus for manufacturing a semiconductor device, wherein the supply amount of excited nitrogen is switched from the first value to the second value. The substrate and the metal film surrounded by the insulating film and the insulating film is exposed to heat, boronitride zirconium film on the substrate surface under heating by supplying nitrogen excited with Zr (BH _{4) 4} to the substrate A method of manufacturing a semiconductor device comprising a step of forming a film,
The step of forming the zirconium boronitride film includes
A method of manufacturing a semiconductor device, characterized in that the supply amount of the excited nitrogen is lowered as the film formation time elapses. A method of manufacturing a semiconductor device according to claim 4,
The step of forming the zirconium boronitride film includes
A first zirconium boronitride film, which is a bulk region, is formed by setting the excited nitrogen supply amount to a first value, and the excited nitrogen supply amount is changed from the first value to the first value. A second zirconium boronitride film, which is a surface layer portion, is formed by switching to a lower second value, and the first zirconium boronitride film is covered with the second zirconium boronitride film that is thinner than the first zirconium boronitride film. A method of manufacturing a semiconductor device. A method of manufacturing a semiconductor device according to claim 5,
The step of forming the zirconium boronitride film includes
The excited nitrogen is generated by irradiating the nitrogen gas supplied from the flow rate controller with microwaves, and the flow rate of the nitrogen gas is switched from the first flow rate to the second flow rate while maintaining the microwave output. An apparatus for manufacturing a semiconductor device, wherein the supplied amount of nitrogen is switched from the first value to the second value. A method of manufacturing a semiconductor device according to claim 5 or 6,
Oxidizing the second zirconium boronitride film;
Laminating another insulating film on the second zirconium boronitride film, and forming a recess in the other insulating film extending from the surface of the other insulating film to the metal film through the zirconium boronitride film. When,
And a step of forming a wiring embedded in the recess by laminating a metal film on the other insulating film so as to fill the recess and planarizing the metal film. Manufacturing method.

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