JP5944549B2 - Semiconductor device manufacturing method, substrate processing apparatus, and semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device, a semiconductor device manufacturing method, and a substrate processing apparatus.

  In order to promote high integration and high performance of MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), the gate insulating film is made of a high dielectric constant insulating material (High-k material) and the gate electrode is made of metal. Adoption of a High-k / Metal gate structure is under study. In the PMOS transistor, it is preferable to form the gate electrode with a metal having a high work function of about 4.8 eV to 5.1 eV. For example, it is considered to form the gate electrode with a noble metal such as Pt (platinum). .

In DRAM (Dynamic Random Access Memory), a capacitor insulating film is made of HfO ₂ (hafnium dioxide), ZrO ₂ (zirconium dioxide), TiO ₂ (titanium dioxide), Ta ₂ O ₅ (tantalum pentoxide) having a large dielectric constant. ), Nb ₂ O ₅ (niobium pentoxide), etc., and the formation of a high dielectric constant insulating film has been studied. In order to reduce the leakage current in the capacitor portion, it is effective to form the capacitor electrode with a metal having a large work function. Therefore, when the capacitor insulating film is formed of HfO ₂ or ZrO ₂ having a wide band gap, the capacitor electrode is formed of TiN (titanium nitride) having a work function of about 4.6 eV, for example. Further, when the capacitor insulating film is formed of TiO ₂ or Nb ₂ O ₅ having a narrow band gap, it is considered that the capacitor electrode is formed of a noble metal such as Pt having a high work function of, for example, about 5.1 eV. Yes.

  However, when a metal film (for example, a gate electrode or a capacitor electrode) is formed using an expensive noble metal such as Pt, the manufacturing cost of the semiconductor device may be increased. Further, it has been difficult to form a thin film using a noble metal such as Pt. As another metal having a large work function, a metal such as Ni (nickel) or cobalt (Co) may be used instead of a noble metal such as Pt. However, these metals are relatively easily oxidized, and the formed metal film (gate electrode or capacitor electrode) is oxidized, which may lead to an increase in EOT (equivalent oxide film thickness).

  Therefore, an object of the present invention is to provide a semiconductor device including a metal film having a work function and oxidation resistance required at low cost. Another object of the present invention is to provide a semiconductor device manufacturing method and a substrate processing apparatus capable of forming a metal film having a necessary work function and oxidation resistance at low cost.

  According to one embodiment of the present invention, an insulating film formed over a substrate, and a metal film provided adjacent to the insulating film, the metal film includes a first metal film and a second metal film. The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film is higher than 4.8 eV. A semiconductor device is provided which is made of a material different from the first metal film having a high work function, and the first metal film is provided between the second metal film and the insulating film. .

  According to another aspect of the present invention, an insulating film is formed on a substrate, and a metal film having a laminated structure of a first metal film and a second metal film is formed adjacent to the insulating film. The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film has a work function higher than 4.8 eV. The first metal film is made of a material different from the first metal film, and in the step of forming the metal film, the first metal film is positioned between the second metal film and the insulating film. A method of manufacturing a semiconductor device for forming one metal film is provided.

  According to still another aspect of the present invention, a processing chamber for processing a substrate, a first processing gas supply system for supplying a first processing gas for forming a first metal film into the processing chamber, A second process gas supply system for supplying a second process gas for forming a second metal film in the process chamber, and a control for controlling the first process gas supply system and the second process gas supply system The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film has a work function higher than 4.8 eV. The control unit is made of a material different from the first metal film, and the control unit is formed on the substrate by supplying the first processing gas and the second processing gas into the processing chamber containing the substrate. Forming a metal film having a laminated structure of the first metal film and the second metal film adjacent to the insulating film. In addition, the first process gas supply system and the first metal film are formed so as to form the first metal film so that the first metal film is located between the second metal film and the insulating film. A substrate processing apparatus for controlling the processing gas supply system 2 is provided.

  According to the present invention, it is possible to provide a semiconductor device including a metal film having a necessary work function and oxidation resistance at low cost. Further, according to the present invention, it is possible to provide a semiconductor device manufacturing method and a substrate processing apparatus capable of forming a metal film having a necessary work function and oxidation resistance at low cost.

It is a flowchart of the substrate processing process concerning embodiment of this invention. It is a block diagram of the gas supply system which the substrate processing apparatus concerning embodiment of this invention has. It is a section lineblock diagram at the time of wafer processing of a substrate processing device concerning an embodiment of the present invention. It is a section lineblock diagram at the time of wafer conveyance of a substrate processing device concerning an embodiment of the present invention. (A) is a cross-sectional block diagram of the gate electrode formed by performing a TiN film formation process and a Ni film formation process once, and (b) is a TiN film formation process and a Ni film formation process several times. It is a cross-sectional block diagram of the gate electrode formed by implementing. (A) is a cross-sectional block diagram of a capacitor electrode formed by performing each of the TiN film forming step and the Ni film forming step once, and (b) is a TiN film forming step and a Ni film forming step, respectively. It is a section lineblock diagram of a capacitor electrode formed by carrying out a plurality of times. It is the schematic which shows the energy level of the conventional capacitor electrode which consists of a single layer of a TiN film | membrane. It is the schematic which shows the energy level of the metal film formed by implementing a TiN film formation process and a Ni film formation process once each. It is the schematic which shows the energy level of the metal film formed by carrying out this cycle several times by making a TiN film formation process and a Ni film formation process into 1 cycle. It is a table | surface figure which illustrates the metal group which has a work function higher than 4.8 eV which can comprise a 2nd metal film. It is a flowchart which shows the formation process of Example 1 (SampleB) shown in FIG. 12, and a comparative example (SampleC). It is the schematic explaining the laminated structure of Example 1 (SampleB) of this invention with the laminated structure of the prior art example (SampleA), and the laminated structure of a comparative example (SampleC). FIG. 13 is a graph showing EOTs of Samples A, B, and C shown in FIG. FIG. 13 is a graph showing the relationship between leakage current density and EOT in each of Samples A, B, and C shown in FIG. FIG. 13 is a graph showing the relationship between leakage current density and applied voltage in Samples A, B, and C shown in FIG. (A) is the schematic which shows the laminated structure of Example 2 (SampleD) of this invention, (b) is a graph which shows the relationship between the work function in SampleD, and the film thickness of TiN with the work function of SampleB and C It is. It is a schematic block diagram of the vertical processing furnace of the vertical apparatus which concerns on further another embodiment of this invention, (a) shows a processing furnace part with a longitudinal cross-section, (b) shows a processing furnace part in FIG. ) Is a cross-sectional view taken along line AA of FIG. It is a schematic block diagram of the cluster apparatus which concerns on further another embodiment of this invention.

<One Embodiment of the Present Invention>
(1) Configuration of Substrate Processing Apparatus First, the configuration of the substrate processing apparatus according to the present embodiment will be described with reference to FIGS. FIG. 3 is a cross-sectional configuration diagram of the substrate processing apparatus according to one embodiment of the present invention during wafer processing, and FIG. 4 is a cross-sectional configuration diagram of the substrate processing apparatus according to one embodiment of the present invention during wafer transfer. is there.

(Processing room)
As shown in FIGS. 3 and 4, the substrate processing apparatus according to this embodiment includes a processing container 202. The processing container 202 is configured as a flat sealed container having a circular cross section, for example. Moreover, the processing container 202 is comprised, for example with metal materials, such as aluminum (Al) and stainless steel (SUS). A processing chamber 201 for processing a wafer 200 such as a silicon wafer as a substrate is formed in the processing container 202.

(Support stand)
A support table 203 that supports the wafer 200 is provided in the processing chamber 201. For example, quartz (SiO ₂ ), carbon, ceramics, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), or aluminum nitride (AlN) is formed on the upper surface of the support base 203 that the wafer 200 directly touches. A susceptor 217 is provided as a support plate. In addition, the support base 203 incorporates a heater 206 as a heating means (heating source) for heating the wafer 200. Note that the lower end portion of the support base 203 passes through the bottom portion of the processing container 202.

(Elevating mechanism)
Outside the processing chamber 201, an elevating mechanism 207b for elevating the support base 203 is provided. The wafer 200 supported on the susceptor 217 can be moved up and down by operating the lifting mechanism 207 b to raise and lower the support base 203. The support table 203 is lowered to the position shown in FIG. 4 (wafer transfer position) when the wafer 200 is transferred, and is raised to the position shown in FIG. 3 (wafer processing position) when the wafer 200 is processed. The periphery of the lower end portion of the support base 203 is covered with a bellows 203a, and the inside of the processing chamber 201 is kept airtight.

(Lift pin)
In addition, on the bottom surface (floor surface) of the processing chamber 201, for example, three lift pins 208b are provided so as to rise in the vertical direction. In addition, the support base 203 (including the susceptor 217) is provided with through holes 208a through which the lift pins 208b pass, at positions corresponding to the lift pins 208b. When the support table 203 is lowered to the wafer transfer position, as shown in FIG. 4, the upper ends of the lift pins 208b protrude from the upper surface of the susceptor 217, and the lift pins 208b support the wafer 200 from below. Yes. When the support table 203 is raised to the wafer processing position, as shown in FIG. 3, the lift pins 208b are buried from the upper surface of the susceptor 217, and the susceptor 217 supports the wafer 200 from below. In addition, since the lift pins 208b are in direct contact with the wafer 200, it is desirable to form the lift pins 208b with a material such as quartz or alumina.

(Wafer transfer port)
On the inner wall side surface of the processing chamber 201 (processing container 202), a wafer transfer port 250 for transferring the wafer 200 into and out of the processing chamber 201 is provided. The wafer transfer port 250 is provided with a gate valve 251. By opening the gate valve 251, the processing chamber 201 and the transfer chamber (preliminary chamber) 271 communicate with each other. The transfer chamber 271 is formed in a transfer container (sealed container) 272, and a transfer robot 273 that transfers the wafer 200 is provided in the transfer chamber 271. The transfer robot 273 includes a transfer arm 273 a that supports the wafer 200 when the wafer 200 is transferred. By opening the gate valve 251 while the support table 203 is lowered to the wafer transfer position, the transfer robot 273 can transfer the wafer 200 between the processing chamber 201 and the transfer chamber 271. Yes. The wafer 200 transferred into the processing chamber 201 is temporarily placed on the lift pins 208b as described above. Note that a load lock chamber (not shown) is provided on the opposite side of the transfer chamber 271 from the side where the wafer transfer port 250 is provided, and the transfer robot 273 moves the wafer 200 between the load lock chamber and the transfer chamber 271. Can be transported. The load lock chamber functions as a spare chamber for temporarily storing unprocessed or processed wafers 200.

(Exhaust system)
An exhaust port 260 for exhausting the atmosphere in the processing chamber 201 is provided on the inner wall side surface of the processing chamber 201 (processing container 202) on the opposite side of the wafer transfer port 250. An exhaust pipe 261 is connected to the exhaust port 260 via an exhaust chamber 260a. The exhaust pipe 261 has a pressure regulator 262 such as an APC (Auto Pressure Controller) that controls the inside of the processing chamber 201 at a predetermined pressure. A raw material recovery trap 263 and a vacuum pump 264 are connected in series in this order. An exhaust system (exhaust line) is mainly configured by the exhaust port 260, the exhaust chamber 260a, the exhaust pipe 261, the pressure regulator 262, the raw material recovery trap 263, and the vacuum pump 264.

(Gas inlet)
A gas inlet 210 for supplying various gases into the processing chamber 201 is provided on the upper surface (ceiling wall) of a shower head 240 described later provided in the upper portion of the processing chamber 201. The configuration of the gas supply system connected to the gas inlet 210 will be described later.

(shower head)
A shower head 240 as a gas dispersion mechanism is provided between the gas inlet 210 and the processing chamber 201. The shower head 240 is a dispersion plate 240 a that disperses the gas introduced from the gas introduction port 210, and a shower plate that further uniformly disperses the gas that has passed through the dispersion plate 240 a and supplies it to the surface of the wafer 200 on the support table 203. 240b. The dispersion plate 240a and the shower plate 240b are provided with a plurality of vent holes. The dispersion plate 240 a is disposed so as to face the upper surface of the shower head 240 and the shower plate 240 b, and the shower plate 240 b is disposed so as to face the wafer 200 on the support table 203. Note that spaces are provided between the upper surface of the shower head 240 and the dispersion plate 240a, and between the dispersion plate 240a and the shower plate 240b, respectively, and the spaces are supplied from the gas inlet 210. Function as a first buffer space (dispersion chamber) 240c for dispersing the gas and a second buffer space 240d for diffusing the gas that has passed through the dispersion plate 240a.

(Exhaust duct)
A step portion 201a is provided on the side surface of the inner wall of the processing chamber 201 (processing vessel 202). The step portion 201a is configured to hold the conductance plate 204 in the vicinity of the wafer processing position. The conductance plate 204 is configured as a single donut-shaped (ring-shaped) disk in which a hole for accommodating the wafer 200 is provided in the inner periphery. A plurality of outlets 204 a arranged in the circumferential direction with a predetermined interval are provided on the outer periphery of the conductance plate 204. The discharge port 204 a is formed discontinuously so that the outer periphery of the conductance plate 204 can support the inner periphery of the conductance plate 204.

  On the other hand, a lower plate 205 is locked to the outer peripheral portion of the support base 203. The lower plate 205 includes a ring-shaped concave portion 205b and a flange portion 205a provided integrally on the inner upper portion of the concave portion 205b. The recess 205 b is provided so as to close a gap between the outer peripheral portion of the support base 203 and the inner wall side surface of the processing chamber 201. A part of the bottom of the recess 205b near the exhaust port 260 is provided with a plate exhaust port 205c that exhausts (circulates) gas from the recess 205b to the exhaust port 260 side. The flange portion 205 a functions as a locking portion that locks on the upper outer periphery of the support base 203. When the flange portion 205 a is locked on the upper outer periphery of the support base 203, the lower plate 205 is moved up and down together with the support base 203 as the support base 203 is moved up and down.

  When the support table 203 is raised to the wafer processing position, the lower plate 205 is also raised to the wafer processing position. As a result, the conductance plate 204 held in the vicinity of the wafer processing position closes the upper surface portion of the recess 205b of the lower plate 205, and the exhaust duct 259 having the gas passage region inside the recess 205b is formed. . At this time, due to the exhaust duct 259 (the conductance plate 204 and the lower plate 205) and the support base 203, the inside of the processing chamber 201 is above the processing chamber above the exhaust duct 259 and the processing chamber below the exhaust duct 259. It will be partitioned into a lower part. The conductance plate 204 and the lower plate 205 are made of materials that can be kept at a high temperature, for example, high temperature and high load resistance, in consideration of etching reaction products deposited on the inner wall of the exhaust duct 259 (self cleaning). Preferably, it is made of quartz for use.

  Here, the flow of gas in the processing chamber 201 during wafer processing will be described. First, the gas supplied from the gas inlet 210 to the upper portion of the shower head 240 enters the second buffer space 240d through the first buffer space (dispersion chamber) 240c through a large number of holes in the dispersion plate 240a, and further into the shower. It passes through a large number of holes in the plate 240 b and is supplied into the processing chamber 201, and is uniformly supplied onto the wafer 200. The gas supplied onto the wafer 200 flows radially outward of the wafer 200 in the radial direction. Then, surplus gas after contacting the wafer 200 flows radially on the exhaust duct 259 located on the outer peripheral portion of the wafer 200, that is, on the conductance plate 204 toward the radially outer side of the wafer 200. Is discharged into the gas flow path region (in the recess 205b) in the exhaust duct 259. Thereafter, the gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260 via the plate exhaust port 205c. By flowing the gas in this way, the gas is suppressed from flowing into the lower portion of the processing chamber 201, that is, the back surface of the support base 203 and the bottom surface side of the processing chamber 201.

<Gas supply system>
Next, the configuration of the gas supply system connected to the gas inlet 210 described above will be described with reference to FIG. FIG. 2 is a configuration diagram of a gas supply system (gas supply line) included in the substrate processing apparatus according to the present embodiment.

  The gas supply system of the substrate processing apparatus according to the present embodiment includes a bubbler as a vaporization unit that vaporizes a liquid raw material that is in a liquid state at room temperature, and a raw material gas obtained by vaporizing the liquid raw material using the bubbler. And a reaction gas supply system for supplying a reaction gas different from the material gas into the processing chamber 201. Furthermore, the substrate processing apparatus according to the present embodiment exhausts the processing chamber 201 by bypass without supplying the purge gas supply system for supplying the purge gas into the processing chamber 201 and the source gas from the bubbler into the processing chamber 201. Vent (bypass) system. Below, the structure of each part is demonstrated.

<Bubbler>
Outside the processing chamber 201, a first raw material container (first bubbler) 220a for storing a first raw material (raw material A) as a liquid raw material and a second raw material (raw material B) as a liquid raw material are supplied. A raw material container (second bubbler) 220b is provided. The first bubbler 220a and the second bubbler 220b are each configured as a tank (sealed container) capable of containing (filling) a liquid material therein, and the first material and the second material are vaporized by bubbling to form the first material. It is comprised also as a vaporization part which produces | generates 1 source gas and 2nd source gas. Around the first bubbler 220a and the second bubbler 220b, there are provided a first heater 220a, a second bubbler 220b, and a sub-heater 206a for heating the liquid material inside. For example, TiCl ₄ (Titanium Tetrachloride), which is a metal liquid source containing Ti (titanium) element, is used as the first raw material, and Ni, which is a metal liquid source containing Ni (nickel) element, for example. (PF ₃ ) ₄ (tetrakistrifluorophosphine nickel) is used.

A first carrier gas supply pipe 237a and a second carrier gas supply pipe 237b are connected to the first bubbler 220a and the second bubbler 220b, respectively. A carrier gas supply source (not shown) is connected to upstream ends of the first carrier gas supply pipe 237a and the second carrier gas supply pipe 237b. Further, the downstream end portions of the first carrier gas supply pipe 237a and the second carrier gas supply pipe 237b are immersed in the liquid raw materials accommodated in the first bubbler 220a and the second bubbler 220b, respectively. The first carrier gas supply pipe 237a is provided with a mass flow controller (MFC) 222a as a flow rate controller for controlling the supply flow rate of the carrier gas, and valves va1 and va2 for controlling the supply of the carrier gas. The second carrier gas supply pipe 237b is provided with a mass flow controller (MFC) 222b as a flow rate controller for controlling the supply flow rate of the carrier gas, and valves vb1 and vb2 for controlling the supply of the carrier gas. As the carrier gas, it is preferable to use a gas that does not react with the liquid raw material. For example, an inert gas such as N ₂ gas or Ar gas is preferably used. The first carrier gas supply system, the second carrier gas supply pipe 237a, the second carrier gas supply pipe 237b, the MFCs 222a and 222b, and the valves va1, va2, vb1, and vb2 are mainly used for the first carrier gas supply system and the second carrier gas supply system (first carrier gas). Gas supply line, second carrier gas supply line).

  With the above configuration, the valves va1, va2, vb1, vb2 are opened, and the carrier gas whose flow rate is controlled by the MFCs 222a, 222b from the first carrier gas supply pipe 237a and the second carrier gas supply pipe 237b is supplied to the first bubbler 220a, the second bubbler. It is possible to generate the first source gas and the second source gas by bubbling the first raw material and the second raw material accommodated in the first bubbler 220a and the second bubbler 220b by supplying them into 220b. It becomes. The supply flow rates of the first source gas and the second source gas can be determined from the supply flow rate of the carrier gas. In other words, the supply flow rates of the first source gas and the second source gas can be controlled by controlling the supply flow rate of the carrier gas.

<Raw gas supply system>
The first bubbler 220a and the second bubbler 220b include a first source gas supply pipe 213a that supplies the first source gas and the second source gas generated in the first bubbler 220a and the second bubbler 220b into the processing chamber 201. The second source gas supply pipe 213b is connected to each other. The upstream end portions of the first source gas supply pipe 213a and the second source gas supply pipe 213b communicate with a space existing above the first bubbler 220a and the second bubbler 220b. The downstream end portions of the first source gas supply pipe 213a and the second source gas supply pipe 213b merge and are connected to the gas inlet 210.

  The first source gas supply pipe 213a is provided with valves va5 and va3 in order from the upstream side. The valve va5 is a valve that controls the supply of the first source gas from the bubbler 220a into the first source gas supply pipe 213a, and is provided in the vicinity of the bubbler 220a. The valve va3 is a valve that controls the supply of the first source gas from the first source gas supply pipe 213a into the processing chamber 201, and is provided in the vicinity of the gas inlet 210. The second source gas supply pipe 213b is provided with valves vb5 and vb3 in order from the upstream side. The valve vb5 is a valve that controls the supply of the second source gas from the bubbler 220b into the second source gas supply pipe 213b, and is provided in the vicinity of the bubbler 220b. The valve vb3 is a valve that controls the supply of the second source gas from the second source gas supply pipe 213b into the processing chamber 201, and is provided in the vicinity of the gas inlet 210. The valve va3, the valve vb3, and ve3 described later are configured as highly durable high-speed gas valves. The high durability high-speed gas valve is an integrated valve configured so that gas supply can be switched and gas exhausted quickly in a short time. In addition, the valve ve3 is a high-speed space between the valve va3 of the first source gas supply pipe 213a and the gas inlet 210 and the space between the valve vb3 of the second source gas supply pipe 213b and the gas inlet 210. This valve controls the introduction of purge gas for purging the processing chamber 201 after purging.

  With the above configuration, the first raw material gas and the second raw material gas are generated by vaporizing the liquid raw material in the first bubbler 220a and the second bubbler 220b, and the valves va5, va3, vb5, vb3 are opened, thereby It becomes possible to supply the first source gas and the second source gas into the processing chamber 201 from the source gas supply pipe 213a and the second source gas supply pipe 213b. Mainly, the first source gas supply system, the second source gas supply pipe 213b, the valves va5, va3, vb5 and vb3 are used for the first source gas supply system, the second source gas supply system (first source gas supply line, first 2 source gas supply lines).

  In addition, mainly, the first source gas supply system, the second carrier gas supply system, the first bubbler 220a, the second bubbler 220b, the first source gas supply system, the second source gas supply system, the first source gas supply system, Second raw material supply systems (first raw material supply line and second raw material supply line) are configured. The first raw material supply system and a reaction gas supply system described later constitute a first processing gas supply system, and the second raw material gas supply system constitutes a second processing gas supply system.

<Reactive gas supply system>
In addition, a reaction gas supply source 220 c that supplies a reaction gas is provided outside the processing chamber 201. The upstream end of the reactive gas supply pipe 213c is connected to the reactive gas supply source 220c. The downstream end of the reaction gas supply pipe 213c is connected to the gas inlet 210 through a valve vc3. The reaction gas supply pipe 213c is provided with a mass flow controller (MFC) 222c as a flow rate controller for controlling the supply flow rate of the reaction gas, and valves vc1 and vc2 for controlling the supply of the reaction gas. As the reaction gas, for example, ammonia (NH ₃ ) gas is used. A reactive gas supply system (reactive gas supply line) is mainly configured by the reactive gas supply source 220c, the reactive gas supply pipe 213c, the MFC 222c, and the valves vc1, vc2, and vc3.

<Purge gas supply system>
In addition, purge gas supply sources 220d and 220e for supplying a purge gas are provided outside the processing chamber 201. The upstream ends of the purge gas supply pipes 213d and 213e are connected to the purge gas supply sources 220d and 220e, respectively. The downstream end of the purge gas supply pipe 213d merges with the reaction gas supply pipe 213c and is connected to the gas inlet 210 through a valve vc3. The downstream end of the purge gas supply pipe 213e joins the first source gas supply pipe 213a and the second source gas supply pipe 213b, and is connected to the gas inlet 210 through the valve ve3. The purge gas supply pipes 213d and 213e are provided with mass flow controllers (MFC) 222d and 222e as flow rate controllers for controlling the supply flow rate of the purge gas, and valves vd1, vd2, ve1 and ve2 for controlling the supply of the purge gas, respectively. It has been. As the purge gas, for example, an inert gas such as N ₂ gas or Ar gas is used. A purge gas supply system (purge gas supply line) is mainly configured by the purge gas supply sources 220d and 220e, purge gas supply pipes 213d and 213e, MFCs 222d and 222e, and valves vd1, vd2, vc3, ve1, ve2, and ve3.

<Vent (bypass) system>
Further, upstream ends of the first vent pipe 215a and the second vent pipe 215b are connected to the upstream side of the valves va3 and vb3 of the first source gas supply pipe 213a and the second source gas supply pipe 213b, respectively. Yes. Further, the downstream end portions of the first vent pipe 215a and the second vent pipe 215b merge to be connected downstream of the pressure regulator 262 of the exhaust pipe 261 and upstream of the material recovery trap 263. Yes. The first vent pipe 215a and the second vent pipe 215b are provided with valves va4 and vb4 for controlling the flow of gas, respectively.

  With the above configuration, by closing the valves va3 and vb3 and opening the valves va4 and vb4, the gas flowing in the first source gas supply pipe 213a and the second source gas supply pipe 213b is not supplied into the processing chamber 201. Then, the processing chamber 201 can be bypassed via the first vent pipe 215a and the second vent pipe 215b, and exhausted from the exhaust pipe 261 to the outside of the processing chamber 201, respectively. A first vent system and a second vent system (a first vent line and a second vent line) are mainly configured by the first vent pipe 215a, the second vent pipe 215b, and the valves va4 and vb4.

  As described above, the sub-heater 206a is provided around the first bubbler 220a and the second bubbler 220b. In addition, the first carrier gas supply pipe 237a, the second carrier gas supply pipe 237b, and the first raw material are provided. A sub-heater 206a is also provided around the gas supply pipe 213a, the second source gas supply pipe 213b, the first vent pipe 215a, the second vent pipe 215b, the exhaust pipe 261, the processing vessel 202, the shower head 240, and the like. The sub-heater 206a is configured to prevent re-liquefaction of the first source gas and the second source gas inside these members by heating these members to a temperature of, for example, 100 ° C. or less.

<Controller>
Note that the substrate processing apparatus according to the present embodiment includes a controller 280 that controls the operation of each unit of the substrate processing apparatus. The controller 280 includes a gate valve 251, an elevating mechanism 207b, a transfer robot 273, a heater 206, a sub heater 206a, a pressure regulator (APC) 262, a vacuum pump 264, valves va1 to va5, vb1 to vb5, vc1 to vc3, vd1 to vd2. , Ve1 to ve3, the flow controllers 222a, 222b, 222c, 222d, 222e and the like are controlled.

(2) Substrate Processing Step Subsequently, as one step of the semiconductor device manufacturing process according to the present embodiment, a substrate processing for forming a thin film on a wafer using the above-described substrate processing apparatus in combination with the CVD method and the ALD method. The process will be described with reference to FIG. FIG. 1 is a flowchart of a substrate processing process according to this embodiment. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 280.

Here, a TiN film and a second metal film as a first metal film are formed on a TiO ₂ film as an insulating film (gate insulating film or capacitor insulating film) formed in advance on a wafer 200 as a substrate. An example of forming a metal film having a laminated structure with a Ni film as will be described. The TiN film as the first metal film includes a first source gas (Ti source) obtained by vaporizing the first source (TiCl ₄ ) and a reactive gas (NH ₃ gas) in the processing chamber 201 containing the wafer 200. ) Are alternately supplied by the ALD method. Further, the Ni film as the second metal film supplies the second source gas (Ni source) obtained by vaporizing the second source (Ni (PF ₃ ) ₄ ) into the processing chamber 201 containing the wafer 200. It is formed by the CVD method. The first source gas and the reaction gas constitute a first process gas, and the second source gas constitutes a second process gas.

  In the present specification, the term metal film means a film composed of a conductive substance containing a metal atom, and in addition to a conductive single metal film composed of a single metal, A conductive metal nitride film, a conductive metal oxide film, a conductive metal oxynitride film, a conductive metal composite film, a conductive metal alloy film, a conductive metal silicide film, and the like are also included. The TiN film is a conductive metal nitride film, and the Ni film is a conductive single metal film. This will be described in detail below.

<Substrate Loading Step (S1), Substrate Placement Step (S2)>
First, the elevating mechanism 207b is operated to lower the support table 203 to the wafer transfer position shown in FIG. Then, the gate valve 251 is opened to allow the processing chamber 201 and the transfer chamber 271 to communicate with each other. Then, the wafer 200 to be processed is loaded from the transfer chamber 271 into the processing chamber 201 by the transfer robot 273 while being supported by the transfer arm 273a (S1). A TiO ₂ film as an insulating film (gate insulating film or capacitor insulating film) is formed in advance on the wafer 200 to be processed. The wafer 200 carried into the processing chamber 201 is temporarily placed on the lift pins 208 b protruding from the upper surface of the support table 203. When the transfer arm 273a of the transfer robot 273 returns from the processing chamber 201 to the transfer chamber 271, the gate valve 251 is closed.

  Subsequently, the elevating mechanism 207b is operated to raise the support table 203 to the wafer processing position shown in FIG. As a result, the lift pins 208b are buried from the upper surface of the support table 203, and the wafer 200 is placed on the susceptor 217 on the upper surface of the support table 203 (S2).

<Pressure adjustment step (S3), temperature adjustment step (S4)>
Subsequently, the pressure regulator (APC) 262 controls the pressure in the processing chamber 201 to be a predetermined processing pressure (S3). Further, the power supplied to the heater 206 is adjusted to control the surface temperature of the wafer 200 to a predetermined processing temperature (S4). The temperature adjustment step (S4) may be performed in parallel with the pressure adjustment step (S3), or may be performed prior to the pressure adjustment step (S3). Here, the predetermined processing temperature and processing pressure are processing temperature and processing pressure at which a TiN film can be formed by the ALD method in a TiN film forming step (S5) described later. That is, the processing temperature and the processing pressure are such that the first source gas supplied in the Ti source supply step (S5a) does not self-decompose.

In the substrate loading step (S1), the substrate placement step (S2), the pressure adjustment step (S3), and the temperature adjustment step (S4), the valves va3 and vb3 are closed while the vacuum pump 264 is operated. By opening vd 1, vd 2, vc 3, ve 1, ve 2, ve 3, N ₂ gas is always allowed to flow into the processing chamber 201. Thereby, adhesion of particles on the wafer 200 can be suppressed.

In parallel with the steps S1 to S4, the first raw material (TiCl ₄ ) is vaporized to generate (preliminarily vaporize) a first raw material gas (Ti raw material), that is, TiCl ₄ gas. That is, by opening the valves va1, va2, va5 and supplying the carrier gas whose flow rate is controlled by the MFC 222a from the first carrier gas supply pipe 237a into the first bubbler 220a, the first bubbler 220a accommodated in the first bubbler 220a. The raw material is vaporized by bubbling to generate a first raw material gas (preliminary vaporization step). In this preliminary vaporization step, while the vacuum pump 264 is operated, the valve va4 is opened while the valve va3 is closed, thereby bypassing the process chamber 201 without supplying the first source gas into the process chamber 201 and exhausting it. Keep it. A predetermined time is required to stably generate the first source gas in the first bubbler. Therefore, in the present embodiment, the first source gas is generated in advance, and the flow path of the first source gas is switched by switching the opening and closing of the valves va3 and va4. As a result, it is preferable that the stable supply of the first source gas into the processing chamber 201 can be started or stopped quickly by switching the valve.

<TiN film forming step (S5)>
(Ti raw material supply step (S5a))
Subsequently, the valve va4 is closed and the valve va3 is opened while the vacuum pump 264 is operated, and the supply of the first source gas (Ti source) into the processing chamber 201 is started. The first source gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess first source gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260 and the exhaust pipe 261. At this time, the processing temperature and the processing pressure are set to a processing temperature and a processing pressure at which the first source gas is not self-decomposed, so that an insulating film (a gate insulating film or a capacitor insulating film) formed in advance on the wafer 200 is used. Gas molecules of the first source gas are adsorbed on the TiO ₂ film.

When the first source gas is supplied into the processing chamber 201, the first source gas is diffused in the processing chamber 201 so as to prevent the first source gas from entering the reaction gas supply pipe 213c. It is preferable to keep the valves vd 1, vd 2, and vc 3 open so that the N ₂ gas always flows into the processing chamber 201 so as to encourage.

  After the valve va3 is opened and the supply of the first source gas is started, the valve va3 is closed and the valve va4 is opened when a predetermined time has elapsed, and the supply of the first source gas into the processing chamber 201 is stopped.

(Purge process (S5b))
After the valve va3 is closed and the supply of the first source gas is stopped, the valves vd1, vd2, vc3, ve1, ve2, and ve3 are opened, and N ₂ gas is supplied into the processing chamber 201. The N ₂ gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201, flows through the exhaust duct 259, and is exhausted to the exhaust port 260 and the exhaust pipe 261. As a result, the first source gas remaining in the processing chamber 201 is removed, and the inside of the processing chamber 201 is purged with N ₂ gas.

(Reactive gas supply step (S5c))
When the purge in the processing chamber 201 is completed, the valves vc1, vc2, and vc3 are opened, and supply of the reaction gas (NH ₃ gas) into the processing chamber 201 is started. The reaction gas is dispersed by the shower head 240 and uniformly supplied onto the wafer 200 in the processing chamber 201, and the gas molecules of the first source gas adsorbed on the TiO ₂ film previously formed on the wafer 200 and By reacting, a TiN film of less than 1 atomic layer (less than 1 cm) is formed on the TiO ₂ film. Excess reaction gas and reaction byproducts flow through the exhaust duct 259 and are exhausted to the exhaust port 260 and the exhaust pipe 261. After the valves vc1, vc2, and vc3 are opened and the supply of the reaction gas is started, the valves vc1 and vc2 are closed when a predetermined time has elapsed, and the supply of the reaction gas into the processing chamber 201 is stopped.

Note that when the reaction gas is supplied into the process chamber 201, the reaction gas in the process chamber 201 is prevented from entering the first source gas supply pipe 213a and the second source gas supply pipe 213b. It is preferable that the valves ve 1, ve 2 and ve 3 are kept open and N ₂ gas is always allowed to flow into the processing chamber 201 so as to promote gas diffusion.

(Purge process (S5d))
After the valves vc 1 and vc 2 are closed and the supply of the reaction gas is stopped, the valves vd 1, vd 2, vc 3, ve 1, ve 2 and ve 3 are opened, and N ₂ gas is supplied into the processing chamber 201. The N ₂ gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201, flows through the exhaust duct 259, and is exhausted to the exhaust port 260 and the exhaust pipe 261. As a result, the reaction gas and reaction byproducts remaining in the processing chamber 201 are removed, and the inside of the processing chamber 201 is purged with N ₂ gas.

(Predetermined number of steps (S5e))
The above-mentioned Ti raw material supply step (S5a), purge step (S5b), reaction gas supply step (S5c), and purge step (S5d) are set as one cycle, and this ALD cycle is carried out a predetermined number of times (n1 cycles). A titanium nitride (TiN) film having a desired film thickness as a first metal film is formed on a TiO ₂ film formed in advance on 200. The TiN film as the first metal film has higher oxidation resistance than the Ni film as the second metal film described later.

<Pressure adjustment step (S6), temperature adjustment step (S7)>
Subsequently, the pressure regulator (APC) 262 controls the pressure in the processing chamber 201 to be a predetermined processing pressure (S6). Further, the power supplied to the heater 206 is adjusted to control the surface temperature of the wafer 200 to be a predetermined processing temperature (S7). The temperature adjustment step (S7) may be performed in parallel with the pressure adjustment step (S6), or may be performed prior to the pressure adjustment step (S6). Here, the predetermined processing temperature and processing pressure are processing temperature and processing pressure at which a Ni film can be formed by a CVD method in a Ni film forming step (S8) described later. That is, the processing temperature and the processing pressure are such that the second source gas supplied in the Ni source supply step (S8a) is self-decomposed.

In parallel with the pressure adjustment step (S6) to the temperature adjustment step (S7), the second raw material (Ni (PF ₃ ) ₄ ) is vaporized in preparation for the next Ni film formation step (S8). A raw material gas (Ni raw material), that is, Ni (PF ₃ ) ₄ gas is generated (preliminary vaporization). That is, the valves vb1, vb2, and vb5 are opened, and the second gas contained in the second bubbler 220b is supplied from the second carrier gas supply pipe 237b to the second bubbler 220b by supplying the carrier gas whose flow rate is controlled by the MFC 222b. The raw material is vaporized by bubbling to generate a second raw material gas (preliminary vaporization step). In this preliminary vaporization step, while the vacuum pump 264 is operated, the valve vb4 is opened while the valve vb3 is closed, thereby bypassing the process chamber 201 without supplying the second source gas into the process chamber 201 and exhausting it. Keep it. A predetermined time is required to stably generate the second source gas in the second bubbler. Therefore, in the present embodiment, the second source gas is generated in advance, and the flow path of the second source gas is switched by switching the opening and closing of the valves vb3 and vb4. As a result, it is preferable that the stable supply of the second source gas into the processing chamber 201 can be started or stopped quickly by switching the valve.

<Ni film forming step (S8)>
(Ni raw material supply step (S8a))
Subsequently, the valve vb4 is closed and the valve vb3 is opened while the vacuum pump 264 is operated, and the supply of the second source gas (Ni source) into the processing chamber 201 is started. The second source gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess second source gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260 and the exhaust pipe 261. At this time, since the processing temperature and the processing pressure are set to a processing temperature and processing pressure at which the second source gas is self-decomposed, a CVD reaction occurs when the second source gas supplied onto the wafer 200 is thermally decomposed, As a result, a Ni film is formed on the wafer 200.

When the second source gas is supplied into the processing chamber 201, the second source gas is diffused in the processing chamber 201 so as to prevent the second source gas from entering the reaction gas supply pipe 213c. It is preferable to keep the valves vd 1, vd 2, and vc 3 open so that the N ₂ gas always flows into the processing chamber 201 so as to encourage.

  When a predetermined time has elapsed after opening the valve vb3 and starting the supply of the second source gas, the valve vb3 is closed and the valve vb4 is opened to stop the supply of the second source gas into the processing chamber 201.

(Purge process (S8b))
After the valve vb3 is closed and the supply of the second raw material gas is stopped, the valves vd1, vd2, vc3, ve1, ve2, and ve3 are opened, and N ₂ gas is supplied into the processing chamber 201. The N ₂ gas is dispersed by the shower head 240 and supplied into the processing chamber 201, flows through the exhaust duct 259, and is exhausted to the exhaust port 260 and the exhaust pipe 261. As a result, the second source gas remaining in the processing chamber 201 is removed, and the inside of the processing chamber 201 is purged with N ₂ gas.

(Predetermined number of steps (S8c))
The Ni raw material supply step (S8a) and the purge step (S8b) are performed as one cycle, and this cycle is performed a predetermined number of times (n2 cycles), whereby a TiN film as a first metal film formed on the wafer 200 is formed. Then, a nickel film (Ni film) having a predetermined film thickness is formed as a second metal film. Note that the Ni film as the second metal film is made of a material different from that of the first metal film having a work function higher than 4.8 eV.

<Predetermined number of steps (S9)>
By carrying out this cycle a predetermined number of times (n3 cycles), the pressure adjustment step (S3) to the TiN film formation step (S5) and the pressure adjustment step (S6) to the Ni film formation step (S8) are defined as one cycle. A metal film having a laminated structure of a TiN film as a first metal film and a Ni film as a second metal film is formed on a TiO ₂ film formed in advance on the wafer 200. As described above, the TiN film as the first metal film is made of a material having higher oxidation resistance than the Ni film as the second metal film. The Ni film as the second metal film is made of a material different from that of the first metal film having a work function higher than 4.8 eV. The TiN film as the first metal film is provided between the Ni film as the second metal film and the TiO ₂ film as the insulating film.

<Pressure adjustment step (S10), temperature adjustment step (S11)>
Subsequently, similarly to the above-described pressure adjustment step (S3) and temperature adjustment step (S4), control is performed so that the pressure in the processing chamber 201 becomes a predetermined processing pressure (S10), and the surface temperature of the wafer 200 is predetermined. (S11).

<TiN cap formation process (S12)>
(Ti raw material supply step (S12a))
Subsequently, as in the Ti source supply step (S5a) described above, supply of the first source gas (Ti source) into the processing chamber 201 is started, and when a predetermined time has elapsed, the first source into the processing chamber 201 is started. Stop supplying the source gas.

(Purge process (S12b))
After the supply of the first source gas is stopped, the inside of the processing chamber 201 is purged with N ₂ gas, as in the above-described purge step (S5b).

(Reactive gas supply step (S12c))
When the purge in the processing chamber 201 is completed, the supply of the reaction gas (NH ₃ gas) into the processing chamber 201 is started in the same manner as in the above-described reaction gas supply step (S5c). The supply of the reaction gas into 201 is stopped.

(Purge process (S12d))
After the supply of the reaction gas is stopped, the inside of the processing chamber 201 is purged with N ₂ gas as in the above-described purge step (S5d).

(Predetermined number of steps (S12e))
The above-described Ti raw material supply step (S12a), purge step (S12b), reaction gas supply step (S12c), and purge step (S12d) are defined as one cycle, and this cycle is repeated a predetermined number of times (n4 cycles). A TiN film (TiN cap film) having a predetermined thickness as a first metal film is formed on the metal film (film having a laminated structure of a TiN film and a Ni film) formed by performing the implementation step (S9). Form.

By performing the above steps S3 to S12, a metal film is formed so as to be adjacent to a TiO ₂ film as an insulating film (gate insulating film or capacitor insulating film) formed in advance on the wafer 200. The metal film has a laminated structure of a TiN film as a first metal film and a Ni film as a second metal film. The first metal film is made of a material (TiN) having higher oxidation resistance than the second metal film, and the second metal film is different from the first metal film having a work function higher than 4.8 eV. It is composed of a substance (Ni). The TiN film is provided between the Ni film and the TiO ₂ film. Furthermore, the TiN film (TiN cap film) is also provided on the outermost surface of the metal film. If the number of executions (n3 cycles) in the predetermined number of execution steps (S9) is 1 (1 cycle), the gate electrode as illustrated in FIG. 5A or the example illustrated in FIG. A metal film as a capacitor upper electrode is obtained. Further, when the number of executions (n3 cycles) in the predetermined number of times execution step (S9) is a plurality of times (multiple cycles), the gate electrode as illustrated in FIG. 5B or the example illustrated in FIG. A metal film as a capacitor upper electrode is obtained. Note that the capacitor lower electrode illustrated in FIG. 6 can also be formed by performing the same process as the process for manufacturing the capacitor upper electrode described above.

<Residual gas removal step (S13)>
After a TiN cap film having a predetermined thickness is formed on a metal film (a film having a laminated structure of a TiN film and a Ni film) formed by performing the execution step (S9) a predetermined number of times, the inside of the processing chamber 201 The valves vd1, vd2, vc3, ve1, ve2, ve3 are opened, and N ₂ gas is supplied into the processing chamber 201. The N ₂ gas is dispersed by the shower head 240, supplied into the processing chamber 201, and exhausted to the exhaust pipe 261. As a result, gas and reaction byproducts remaining in the processing chamber 201 are removed, and the inside of the processing chamber 201 is purged with N ₂ gas.

<Substrate unloading step (S14)>
Thereafter, a metal film having a predetermined thickness (a film having a laminated structure of a TiN film and a Ni film) and a procedure opposite to the procedures shown in the substrate loading step (S1) and the substrate placing step (S2) described above, and The wafer 200 after the TiN cap film is formed is unloaded from the processing chamber 201 into the transfer chamber 271 to complete the substrate processing step according to the present embodiment.

As processing conditions of the wafer 200 in the TiN film forming step (S5) in the present embodiment,
Treatment temperature: 250-550 ° C, preferably 350-550 ° C,
Processing pressure: 50 to 5000 Pa,
Bubbling carrier gas (N ₂ ) supply flow rate: 10 to 1000 sccm
(First source gas (TiCl ₄ ) supply flow rate: 0.1 to 2 sccm,
Reaction gas (NH ₃ ) supply flow rate: 10 to 1000 sccm,
Purge gas (N ₂ ) supply flow rate: 100 to 10,000 sccm,
Film thickness (TiN film): 0.2 to 4 nm
Is exemplified.

Further, as the processing conditions of the wafer 200 in the Ni film forming step (S8) in the present embodiment,
Treatment temperature: 150-250 ° C, preferably 150-200 ° C
Processing pressure: 50 to 5000 Pa,
Bubbling carrier gas (N ₂ ) supply flow rate: 10 to 1000 sccm,
(Second source gas (Ni (PF ₃ ) ₄ ) supply flow rate: 0.1 to 2 sccm,
Purge gas (N ₂ ) supply flow rate: 100 to 10,000 sccm,
Film thickness (Ni film): 0.5 to 10 nm, preferably 4 to 5 nm,
Is exemplified.

  The total film thickness formed in the execution step (S9) a predetermined number of times, that is, the film thickness of the metal film having a laminated structure of the TiN film as the first metal film and the Ni film as the second metal film. Is exemplified by 10 to 30 nm.

In addition, as a processing condition of the wafer 200 in the TiN cap forming step (S12) in the present embodiment,
Treatment temperature: 250-550 ° C, preferably 350-550 ° C,
Processing pressure: 50 to 5000 Pa,
Bubbling carrier gas (N ₂ ) supply flow rate: 10 to 1000 sccm
(First source gas (TiCl ₄ ) supply flow rate: 0.1 to 2 sccm,
Reaction gas (NH ₃ ) supply flow rate: 10 to 1000 sccm,
Purge gas (N ₂ ) supply flow rate: 100 to 10,000 sccm,
Film thickness (TiN film): 0.2 to 50 nm, preferably 1 to 10 nm,
Is exemplified.

If the thickness of the TiN film formed in the TiN film forming step (S5) is less than 0.2 nm, the TiN film formed between the Ni film and the TiO ₂ film is a continuous layer of one or more layers. In other words, the Ni film and the TiO ₂ film may be in direct contact with each other because of a discontinuous layer. In some cases, the oxygen component contained in the TiO ₂ film enters the Ni film from the contacted portion and oxidizes the Ni film. When the thickness of the TiN film formed in the TiN film forming step (S5) exceeds 4 nm, the effective work function of the entire metal film is not the work function of the Ni film (about 5.15 eV), but the TiN film The work function may be approached (approximately 4.6 eV). Therefore, the thickness of the TiN film formed in the TiN film forming step (S5) is preferably in the range of 0.2 to 4 nm.

Further, if the processing temperature in the Ni film forming step (S8) is less than 150 ° C., the second raw material (Ni (PF ₃ ) ₄ ) is not self-decomposed in the Ni raw material supply step (S8a), and the film formation reaction by CVD is No longer occurs. In addition, when the processing temperature exceeds 250 ° C. in the above processing pressure zone, the film forming rate increases explosively, and it becomes difficult to control the film thickness. Therefore, in the Ni film forming step (S8), in order to cause a film forming reaction by CVD and to control the film thickness, it is necessary to set the processing temperature to 150 ° C. or higher and 250 ° C. or lower.

  In the present embodiment, it is preferable to perform the TiN film forming step (S5) and the Ni film forming step (S8) at the same processing temperature and / or the same processing pressure. That is, in this embodiment, it is preferable to perform the TiN film forming step (S5) and the Ni film forming step (S8) at a constant processing temperature and / or a constant processing pressure. If the processing temperature and the processing pressure are set to predetermined values within the above-described exemplary ranges, film formation by the ALD method and film formation by the CVD method can be performed in the same condition. In this case, a process temperature changing step when shifting from the TiN film forming step (S5) to the Ni film forming step (S8) and when shifting from the Ni film forming step (S8) to the TiN film forming step (S5). The process pressure changing step is unnecessary, and the throughput can be improved.

(3) Effects According to the Embodiment According to the present embodiment, one or more effects described below are exhibited.

(A) According to the present embodiment, a TiN film having higher oxidation resistance than the Ni film is formed in the lowermost layer of the metal film, that is, between the Ni film and the TiO ₂ film (interface). Since the TiN film has higher oxidation resistance than the Ni film, for example, when the Ni film is formed by the CVD method, the wafer 200 after the metal film is formed is heated at a temperature of, for example, about 400 ° C. In this case, it is possible to prevent the oxygen component contained in the TiO ₂ film from entering the Ni film through the interface and oxidizing the Ni film. In particular, in the present embodiment, the thickness of the TiN film formed in the TiN film forming step (S5) is 0.2 nm or more. For this reason, the TiN film formed between the Ni film and the TiO ₂ film can surely be a continuous layer of one or more layers, and the Ni film and the TiO ₂ film are prevented from being in direct contact with each other. And oxidation of the Ni film can be effectively suppressed. Then, oxidation of the metal film can be suppressed, and an increase in EOT (equivalent oxide film thickness) can be prevented.

(B) According to the present embodiment, a TiN film (TiN cap layer) having higher oxidation resistance than the Ni film is formed on the uppermost layer of the metal film, that is, the exposed surface of the metal film. This can prevent oxygen in the atmosphere from entering the Ni film through the exposed surface of the metal film, and can suppress the oxidation of the Ni film. For example, when the wafer 200 with the metal film exposed is transported to the next process, oxygen in the atmosphere enters the Ni film through the exposed surface of the metal film and oxidizes the Ni film at room temperature. Can be suppressed. In particular, in the present embodiment, since the thickness of the TiN film formed in the TiN cap forming step (S12) is 0.2 to 50 nm, preferably 1 to 10 nm, the TiN film covering the surface of the Ni film is surely provided. In addition, it is possible to form a continuous layer of one or more layers, the Ni film can be prevented from coming into direct contact with the atmosphere, and the oxidation of the Ni film can be effectively suppressed. Then, oxidation of the metal film can be suppressed, and an increase in EOT (equivalent oxide film thickness) can be prevented.

(C) According to the present embodiment, the second metal film is made of Ni (substance different from the first metal film) having a work function higher than 4.8 eV. The work function of TiN constituting the first metal film is estimated to be about 4.6 eV, but the work function of Ni is 5.15 eV as shown in FIG. Thereby, the effective work function of the whole metal film having a laminated structure of the TiN film and the Ni film can be brought close to the work function (5.15 eV) of the Ni film. In particular, according to the present embodiment, the thickness of the Ni film formed in the Ni film forming step (S8) is made larger than the thickness of the TiN film formed in the TiN film forming step (S5). Thereby, the influence of the work function of the Ni film, which is a thick film, is increased, and the effective work function of the entire metal film having the laminated structure of the TiN film and the Ni film is expressed as the work function (5.15 eV) of the Ni film. Can be closer. Thereby, when the metal film is applied to the capacitor electrode, the leakage current in the capacitor portion can be reduced.

  For example, the thickness of the Ni film formed in the Ni film forming step (S8) is 0.5 to 10 nm, preferably 4 to 5 nm, and the thickness of the TiN film formed in the TiN film forming step (S5) is 0.2. By setting the thickness of the Ni film to be larger than the thickness of the TiN film and performing the TiN film forming step (S5) and the Ni film forming step (S8) once each, FIG. ) And the metal film as illustrated in FIG. 6A, the influence of the work function of the Ni film that is a thick film increases, and the effective work function of the entire metal film is about 5.0 eV. can do. Further, for example, the TiN film forming step (S5) and the Ni film forming step (S8) are set as one cycle, and this cycle is performed a plurality of times, as illustrated in FIG. 5B and FIG. 6B. When the metal film is formed, the effective work function of the entire metal film can be adjusted to a desired value. That is, in this case, since the work function of the TiN film and the work function of the Ni film are influenced by each other, the effective work function of the entire metal film is adjusted by adjusting the film thickness ratio between the TiN film and the Ni film. Can be adjusted to a desired value between 4.6 eV and 5.0 eV. In any case, when the thickness of the TiN film formed in the TiN film forming step (S5) exceeds 4 nm, the effective work function of the entire metal film is reduced and the work function of the TiN film (4.6 eV) Degree).

FIG. 7 is a schematic diagram showing energy levels of a conventional capacitor electrode composed of a single layer of TiN film. A leakage current in a capacitor structure (MIM structure) in which a capacitor insulating film (for example, TiO ₂ film) is sandwiched between TiN films is mainly due to a band offset (conduction band offset) between the work function of the capacitor electrode and the conduction band side of the capacitor insulating film. Determined. In general, since a voltage of ± 1.0 V is applied between the capacitor electrodes, the conduction band offset is preferably higher than 1.0 eV. Since the work function of TiN is about 4.6 eV, when a TiO ₂ film is used as the capacitor insulating film, the conduction band offset can be secured only about 1.0 eV, and the leakage current increases.

In contrast, if the metal film according to the present embodiment is used as a capacitor electrode, the leakage current in the MIM structure can be greatly reduced. FIG. 8 is a schematic diagram showing the energy levels of the metal film formed by performing the TiN film forming step (S5) and the Ni film forming step (S8) once. In this case, as described above, the work function of the metal film having the laminated structure of the TiN film and the Ni film is set to be approximately the same as the work function (5.15 eV) of the Ni film (for example, about 5.0 eV). it can. Therefore, when a TiO ₂ film is used as the insulating film, the conduction band offset can be secured at about 1.4 eV, and the leakage current can be greatly reduced. FIG. 9 is a schematic diagram showing energy levels of a metal film formed by performing this cycle a plurality of times, with the TiN film forming step (S5) and the Ni film forming step (S8) as one cycle. . In this case, as described above, the work function of the metal film having the laminated structure of the TiN film and the Ni film can be adjusted to a desired value (for example, 4.8 eV) between 4.6 eV and 5.0 eV, for example. I can do it. Therefore, when a TiO ₂ film is used as the insulating film, the conduction band offset can be set to a desired value between 1.0 to 1.4 eV (for example, 1.2 eV), and the leakage current is effectively reduced. Can be made.

(D) According to the present embodiment, the second metal film having a work function higher than 4.8 eV is used as an expensive noble metal such as Au, Ag, Pt, Pd, Rh, Ir, Ru, and Os. Without using a Ni film which is a non-noble metal film. Thereby, the manufacturing cost of the semiconductor device can be reduced.

(E) Further, according to the present embodiment, the Ni film is formed by the CVD method among the metal films having the laminated structure of the TiN film and the Ni film. Therefore, the total film formation rate of the metal film can be improved as compared with the case where the film is formed only by the ALD method, and the throughput can be improved.

<Other Embodiments of the Present Invention>
In the above-described embodiment, the example in which the liquid raw material contained in the bubbler is vaporized by bubbling has been described, but the present invention is not limited to this, and the liquid raw material is vaporized using a vaporizer instead of the bubbler. Also good.

In the above-described embodiment, an example in which TiCl ₄ is used as a Ti raw material in the TiN film forming step (S5) has been described. However, the present invention is not limited to this, and TDMAT (tetrakisdimethylaminotitanium, TiTi) is used instead of TiCl _4. Ti raw materials such as [N (CH ₃ ) ₂ ] ₄ ) may be used.

In the above-described embodiment, the case where the TiO ₂ film which is a high dielectric constant insulating film is used as the insulating film has been described. However, the present invention is not limited to this, and for example, a hafnium oxide (HfO ₂ ) film, an oxide film as the insulating film Zirconium (ZrO ₂ ) film, niobium oxide (Nb ₂ O ₅ ) film, tantalum oxide (Ta ₂ O ₅ ) film, Al-doped hafnium oxide (HfAlO) film, Al-doped zirconium oxide (ZrAlO) film, titanium It can also be suitably applied when using a high dielectric constant insulating film such as a strontium oxide (SrTiO) film, a barium strontium titanate (BaSrTiO) film, a lead zirconate titanate (PZT) film, or other insulating films. is there.

  In the above-described embodiment, the case where the TiN film is used as the first metal film has been described. However, the present invention is not limited to this, and the first metal film may be, for example, a tantalum nitride (TaN) film or aluminum titanium nitride. The present invention can also be suitably applied when using other films such as a (TiAlN) film or an aluminum tantalum nitride (TaAlN) film. Note that the TaN film, the TiAlN film, and the TiAlN film all have higher oxidation resistance than the second metal film (Ni film), and further have higher oxidation resistance than the TiN film, and are preferably used as an oxidation barrier film. I can do it. The TaN film is a conductive metal nitride film, and the TiAlN film and the TaAlN film are conductive metal composite films.

  In the above-described embodiment, the case where the Ni film is used as the second metal film has been described. However, the present invention is not limited thereto, and examples of the second metal film include beryllium (Be), carbon (C), The present invention can also be suitably applied to a case where a non-noble metal such as cobalt (Co), selenium (Se), tellurium (Te), or rhenium (Re) and having a work function higher than 4.8 eV is used. These films are all conductive single metal films. FIG. 10 is a table illustrating a group of metals that are non-noble metals that can form the second metal film and have a work function higher than 4.8 eV.

  Examples 1 and 2 of the present invention will be described below together with conventional examples and comparative examples with reference to FIGS.

Example 1
FIG. 12 is a schematic diagram illustrating the stacked structure of Sample B (Example 1) of the present invention together with the stacked structure of Sample A (conventional example) and the stacked structure of Sample C (comparative example). FIG. 11 is a flowchart showing the steps of forming Sample A (conventional example), Sample B (Example 1), and Sample C (Comparative Example) shown in FIG.

As shown in FIG. 11, in order to manufacture Sample B (Example 1), first, a silicon substrate (Si-Sub) was surface-treated (cleaned) with hydrogen fluoride (HF) (HF treatment). Then, a TiN film as a lower electrode was formed on the silicon substrate (Bottom Metal deposition). Then, an Al-doped HfO ₂ film (HfAlO film) as a capacitor insulating film (High-k film) was formed on the TiN film (High-k Deposition). Here, the composition ratio of Hf and Al in the capacitor insulating film was 19: 1. Then, after the heat treatment (PDA) under the temperature condition of 700 ° C., the TiN film is obtained by performing the same process as the execution process (S9) a predetermined number of times in the above embodiment using the substrate processing apparatus in the above embodiment. A stacked structure (Ni / TiN-laminate) in which a plurality of layers and Ni films are alternately stacked is formed (Top Metal deposition). In Sample B, the formation of the laminated structure is started from the formation of the TiN film (TiN Start), and the TiN film is inserted between the Ni film and the HfAlO film. Here, the thickness of each of the TiN film and the Ni film was set to 1 nm, the number of executions in the predetermined number of steps (S9) was set to 5, and the thickness of the laminated structure was set to 10 nm. Then, a TiN film (TiN cap film) having a thickness of 50 nm is formed on the laminated structure of the TiN film and the Ni film by performing the same process as the TiN cap forming process (S12) in the above-described embodiment. Then, a metal film (a laminated film of a TiN film and a Ni film and a TiN cap film formed on the laminated structure) as an upper electrode was formed. Then, the gate structure was patterned by photolithography (Gate Patterning), and after performing FGA treatment under a temperature condition of 400 ° C. (FGA), an Al film was formed on the back surface (Back Side Al deposition).

  In Sample C (Comparative Example), a stacked structure (Ni / TiN-laminate) in which Ni films and TiN films are alternately stacked is formed on a capacitor insulating film (Top Material deposition). In Sample C, the formation of the laminated structure is started from the formation of the Ni film (Ni Start), and the Ni film and the HfAlO film are in direct contact with each other. The other formation flow and conditions were the same as in Sample B.

  In Sample A (conventional example), a laminated structure of a TiN film and a Ni film was not formed on the capacitor insulating film, but an upper electrode (TiN) was formed by a single layer of TiN film. In Sample A, a TiN cap film having a thickness of 50 nm was not formed. The other formation flow and conditions were the same as in Sample B.

  FIG. 13 is a graph showing the EOT (equivalent oxide film thickness) of Sample A (conventional example), B (Example 1), and C (Comparative Example) shown in FIG. The vertical axis in FIG. 13 indicates EOT (nm), and the horizontal axis indicates each sample. According to FIG. 13, the EOT of Sample B (Example 1) is 0.80 (nm) or less, which is almost the same as the EOT of Sample A (conventional example) in which a single layer of TiN having high oxidation resistance is formed. It can be seen that it has not increased. On the other hand, in Sample C (comparative example) in which the stacked structure is formed so that the Ni film and the HfAlO film are in direct contact, it can be seen that EOT is increased to 1.40 (nm). This is presumably because the Ni film was oxidized by the oxygen component contained in the HfAlO film. That is, the formation of the laminated structure is started from the formation of the TiN film as in Sample B (TiN Start), and the NiN film is formed by inserting the TiN film between the Ni film and the HfAlO film. It can be understood that the increase in EOT can be suppressed effectively.

FIG. 14 is a graph showing the relationship between leakage current density Jg and EOT in Sample A (conventional example), B (example 1), and C (comparative example) shown in FIG. The vertical axis in FIG. 14 indicates the leakage current density Jg (A / cm ² ) when the voltage Vg applied between the upper electrode and the lower electrode is −1 V, and the horizontal axis indicates EOT (nm). Show. In FIG. 14, ♦ indicates Sample A (conventional example), ▲ indicates Sample B (Example 1), and ◇ indicates Sample C (comparative example). According to FIG. 14, it can be seen that Sample B (▲) has almost no increase in EOT and leak current density Jg can be reduced by one digit compared to Sample A (♦). Also, it can be seen that Sample C (marked with) has a significant increase in EOT, although the leakage current density Jg can be reduced by one digit as compared with Sample A (marked with ♦). That is, it can be seen that the increase in EOT can be suppressed and the leakage current can be reduced by forming the TiN film between the Ni film and the HfAlO film as in Sample B.

FIG. 15 is a graph showing the relationship between the leakage current density Jg and the applied voltage vg in Sample A (conventional example), B (example 1), and C (comparative example) shown in FIG. The vertical axis in FIG. 15 indicates the leakage current density Jg (A / cm ² ), and the horizontal axis indicates the voltage Vg (V) applied between the upper electrode and the lower electrode. Further, the one-dot chain line in FIG. 15 indicates Sample A (conventional example), the solid line indicates Sample B (Example 1), and the dotted line indicates Sample C (Comparative Example). According to FIG. 15, the leak current density Jg of Sample B (solid line) and Sample C (dotted line) within the general voltage range (± 1 V range) applied between the capacitor electrodes is that of Sample A (conventional example). It can be seen that the leakage current density Jg is one order of magnitude smaller. That is, it can be seen that the leakage current can be reduced by forming a laminated structure of the TiN film and the Ni film as in Sample B.

(Example 2)
FIG. 16A is a schematic view showing a laminated structure of Example 2 (Sample D) of the present invention. In Sample D, a metal film as a gate electrode was formed by laminating a TiN film and a Ni film one by one on an SiO ₂ film as a gate insulating film. The TiN film was formed so as to be inserted between the Ni film and the SiO ₂ film. Moreover, the thickness of the TiN film was changed to 0.2 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, and 10 nm to form a plurality of samples having different thicknesses of the TiN film. The thickness of the Ni film was 20 nm.

  FIG. 16B is a graph showing the relationship between the work function of the metal film in Sample D and the film thickness of the TiN film together with the work functions of the metal films of Sample B and C. In FIG. 16B, the vertical axis represents the work function (eV) of the metal film, and the horizontal axis represents the thickness (nm) of the TiN film in Sample D (Example 2). In FIG. 16B, the □ marks indicate the work function of the SampleD metal film, the solid line indicates the work function of the SampleC metal film, and the dotted line indicates the work function of the SampleB metal film. According to FIG. 16B, when the film thickness of the TiN film in Sample D is 4 nm or less, the effective work function of the entire metal film having the laminated structure of the TiN film and the Ni film is expressed as the work function of the Ni film. It can be seen that it is possible to approach (5.15 eV). However, it can be seen that when the thickness of the TiN film exceeds 4 nm, the effect of the work function of TiN becomes strong, and the effective work function of the entire metal film decreases. Therefore, the thickness of the TiN film is preferably 4.0 nm or less.

<Still another embodiment of the present invention>
In the above-described embodiment, an example in which film formation is performed using a single-wafer type apparatus that processes one substrate at a time as the substrate processing apparatus has been described, but the present invention is not limited to the above-described embodiment. For example, the film may be formed using a batch type vertical apparatus that processes a plurality of substrates at once as the substrate processing apparatus.

  FIG. 17 is a schematic configuration diagram of a vertical processing furnace of a vertical apparatus suitably used in the present embodiment. FIG. 17A is a vertical sectional view of the processing furnace 302, and FIG. 17B is a processing furnace 302. The portion is shown by a cross-sectional view along line AA in FIG.

  As shown in FIG. 17A, the processing furnace 302 has a heater 307 as a heating means (heating mechanism). The heater 307 has a cylindrical shape and is vertically installed by being supported by a heater base as a holding plate.

Inside the heater 307, a process tube 303 as a reaction tube is disposed concentrically with the heater 307. The process tube 303 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and has a cylindrical shape with the upper end closed and the lower end opened. A processing chamber 301 is formed in a cylindrical hollow portion of the process tube 303 so that wafers 200 as substrates can be accommodated in a state of being aligned in multiple stages in a vertical posture in a horizontal posture by a boat 317 described later.

  A manifold 309 is disposed below the process tube 303 concentrically with the process tube 303. The manifold 309 is made of, for example, stainless steel and is formed in a cylindrical shape with an upper end and a lower end opened. The manifold 309 is engaged with the process tube 303 and is provided to support the process tube 303. An O-ring 320a as a seal member is provided between the manifold 309 and the process tube 303. Since the manifold 309 is supported by the heater base, the process tube 303 is vertically installed. A reaction vessel is formed by the process tube 303 and the manifold 309.

  A first nozzle 333 a as a first gas introduction part and a second nozzle 333 b as a second gas introduction part are connected to the manifold 309 so as to penetrate the side wall of the manifold 309. Each of the first nozzle 333a and the second nozzle 333b has an L shape having a horizontal portion and a vertical portion, the horizontal portion is connected to the manifold 309, and the vertical portion is between the inner wall of the process tube 303 and the wafer 200. It is provided in an arc-shaped space so as to rise in the stacking direction of the wafer 200 along the inner wall above the lower part of the process tube 303. A first gas supply hole 348a and a second gas supply hole 348b, which are supply holes for supplying gas, are provided on the side surfaces of the vertical portions of the first nozzle 333a and the second nozzle 333b, respectively. The first gas supply hole 348a and the second gas supply hole 348b have the same opening area from the lower part to the upper part, and are provided at the same opening pitch.

  The gas supply system connected to the first nozzle 333a and the second nozzle 333b is the same as in the above-described embodiment. However, in the present embodiment, the first raw material gas supply system and the second raw material gas supply system are connected to the first nozzle 333a, and the reactive gas supply system is connected to the second nozzle 333b. Different. That is, in the present embodiment, the source gas (first source gas, second source gas) and the reaction gas are supplied by separate nozzles. Furthermore, the first source gas and the second source gas may be supplied by separate nozzles.

  The manifold 309 is provided with an exhaust pipe 331 that exhausts the atmosphere in the processing chamber 301. A vacuum pump 346 as an evacuation device is connected to the exhaust pipe 331 through a pressure sensor 345 as a pressure detector and an APC (Auto Pressure Controller) valve 342 as a pressure regulator. By adjusting the APC valve 342 based on the detected pressure information, the processing chamber 301 is configured to be evacuated so that the pressure in the processing chamber 301 becomes a predetermined pressure (degree of vacuum). Note that the APC valve 342 is configured to open and close the valve to evacuate / stop evacuation in the processing chamber 301, and to adjust the valve opening to adjust the pressure in the processing chamber 301. Open / close valve.

  Below the manifold 309, a seal cap 319 is provided as a furnace port lid that can airtightly close the lower end opening of the manifold 309. The seal cap 319 is brought into contact with the lower end of the manifold 309 from the lower side in the vertical direction. The seal cap 319 is made of a metal such as stainless steel and is formed in a disk shape. On the upper surface of the seal cap 319, an O-ring 320b is provided as a seal member that contacts the lower end of the manifold 309. On the opposite side of the seal cap 319 from the processing chamber 301, a rotation mechanism 367 for rotating a boat 317 described later is installed. A rotation shaft 355 of the rotation mechanism 367 passes through the seal cap 319 and is connected to the boat 317, and is configured to rotate the wafer 200 by rotating the boat 317. The seal cap 319 is configured to be moved up and down in a vertical direction by a boat elevator 315 as an elevating mechanism disposed outside the process tube 303, and thereby the boat 317 is carried into and out of the processing chamber 301. It is possible.

  The boat 317 as a substrate holder is made of a heat-resistant material such as quartz or silicon carbide, and is configured to hold a plurality of wafers 200 in a horizontal posture and in a state where the centers are aligned with each other and held in multiple stages. Yes. A heat insulating member 318 made of a heat resistant material such as quartz or silicon carbide is provided at the lower part of the boat 317 so that heat from the heater 307 is not easily transmitted to the seal cap 319 side. A temperature sensor 363 as a temperature detector is installed in the process tube 303, and the temperature in the processing chamber 301 is adjusted by adjusting the power supply to the heater 307 based on the temperature information detected by the temperature sensor 363. Is configured to have a predetermined temperature distribution. The temperature sensor 363 is provided along the inner wall of the process tube 303, similarly to the first nozzle 333a and the second nozzle 333b.

  The controller 380 which is a control unit (control means) includes an APC valve 342, a heater 307, a temperature sensor 363, a vacuum pump 346, a rotation mechanism 367, a boat elevator 315, valves va1 to va5, vb1 to vb5, vc1 to vc3, vdl1. Controls the operations of vd2, ve1 to ve3, flow controllers 222a, 222b, 222c, 222d, and 222e.

  Next, a substrate processing step of forming a metal film on the wafer 200 by the CVD method as one step of the semiconductor device manufacturing process using the processing furnace 302 of the vertical apparatus according to the above configuration will be described. In the following description, the operation of each part constituting the vertical apparatus is controlled by the controller 380.

  A plurality of wafers 200 are loaded into the boat 317 (wafer charge). Then, as shown in FIG. 17A, the boat 317 holding the plurality of wafers 200 is lifted by the boat elevator 315 and loaded into the processing chamber 301 (boat loading). In this state, the seal cap 319 is in a state of sealing the lower end of the manifold 309 via the O-ring 320b.

  The inside of the processing chamber 301 is evacuated by a vacuum pump 346 so that the inside of the processing chamber 301 has a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 301 is measured by the pressure sensor 345, and the APC valve 342 is feedback-controlled based on the measured pressure. In addition, heating is performed by the heater 307 so that the inside of the processing chamber 301 has a desired temperature. At this time, feedback control of the power supply to the heater 307 is performed based on the temperature information detected by the temperature sensor 363 so that the inside of the processing chamber 301 has a desired temperature distribution. Then, the wafer 200 is rotated by rotating the boat 317 by the rotation mechanism 367.

Thereafter, the TiN film and the Ni film are laminated on the TiO ₂ film previously formed on the wafer 200 by the same procedure as the TiN film forming process (S5) to the TiN cap forming process (S12) in the above-described embodiment. A metal film having a structure is formed, and a TiN film (TiN cap film) having a predetermined thickness is further formed. And a residual gas removal process is performed in the procedure similar to the residual gas removal process (S13) in the above-mentioned embodiment.

  Thereafter, the seal cap 319 is lowered by the boat elevator 315 to open the lower end of the manifold 309 and the boat 317 holds the wafer 200 after the metal film and the TiN cap film having a predetermined thickness are formed. Then, it is unloaded from the lower end of the manifold 309 to the outside of the process tube 303 (boat unloading). Thereafter, the processed wafer 200 is taken out from the boat 317 (wafer discharge).

  Even when the vertical apparatus according to the present embodiment is used, the same process as the substrate processing process according to the above-described embodiment can be performed, and the same effect as in the above-described embodiment can be obtained.

<Still another embodiment of the present invention>
Further, in the above-described embodiment, an example in which the TiN film and the Ni film are formed in the same processing chamber has been described. However, the present invention is not limited to this embodiment, and each film is formed in different processing chambers. It may be. In that case, for example, a substrate processing apparatus (cluster apparatus) as a multi-chamber type substrate processing system including a plurality of processing chambers as illustrated in FIG. 18 can be used. Hereinafter, an example in which the TiN film and the Ni film are separately formed in different processing chambers using this cluster apparatus will be described. In the cluster apparatus according to the present embodiment, a FOUP (Front Opening Unified Pod) 1 is used as a wafer transfer carrier (substrate storage container) for transferring the wafer 200.

  As shown in FIG. 18, the cluster apparatus 10 has a first wafer transfer chamber (hereinafter referred to as negative pressure) as a transfer module (transfer chamber) configured to withstand a pressure (negative pressure) less than atmospheric pressure. A negative pressure transfer chamber 11 (hereinafter referred to as a negative pressure transfer chamber housing) 12 is formed in a box shape with a heptagonal plan view and closed at both upper and lower ends. Has been. The negative pressure transfer chamber housing 12 is configured as a transfer container (sealed container). At the center of the negative pressure transfer chamber 11, a wafer transfer machine (hereinafter referred to as a negative pressure transfer machine) 13 as a transfer robot for transferring the wafer 200 under a negative pressure is installed.

  The largest side wall (front wall) of the seven side walls of the negative pressure transfer chamber housing 12 has a carry-in spare chamber (hereinafter referred to as a load-in chamber) 14 as a load lock module (load lock chamber) and a carry-out chamber. A spare room (hereinafter referred to as a carry-out room) 15 is connected adjacently. The housing of the carry-in chamber 14 and the housing of the carry-out chamber 15 are each formed in a box shape with a substantially rhombus in plan view and closed at both upper and lower ends, and are configured in a load lock chamber structure that can withstand negative pressure. Yes.

  On the opposite side of the carry-in chamber 14 and the carry-out chamber 15 from the negative pressure transfer chamber 11, the second wafer transfer as a front end module configured to maintain a pressure higher than atmospheric pressure (hereinafter referred to as positive pressure). A loading chamber (hereinafter referred to as a positive pressure transfer chamber) 16 is connected adjacently, and the casing of the positive pressure transfer chamber 16 is formed in a box shape in which a plan view is a horizontally long rectangle and both upper and lower ends are closed. Yes. A gate valve 17A is installed at the boundary between the carry-in chamber 14 and the positive pressure transfer chamber 16, and a gate valve 17B is installed between the carry-in chamber 14 and the negative pressure transfer chamber 11. A gate valve 18 </ b> A is installed at the boundary between the carry-out chamber 15 and the positive pressure transfer chamber 16, and a gate valve 18 </ b> B is installed between the carry-out chamber 15 and the negative pressure transfer chamber 11. The positive pressure transfer chamber 16 is provided with a second wafer transfer machine (hereinafter referred to as a positive pressure transfer machine) 19 as a transfer robot for transferring the wafer 200 under positive pressure. The positive pressure transfer machine 19 is configured to be moved up and down by an elevator installed in the positive pressure transfer chamber 16, and is configured to be reciprocated in the left-right direction by a linear actuator. A notch aligning device 20 is installed at the left end of the positive pressure transfer chamber 16.

  Three wafer loading / unloading ports 21, 22, and 23 are opened next to each other on the front wall of the positive pressure transfer chamber 16. The pressure transfer chamber 16 is configured to be able to carry in and out. Pod openers 24 are respectively installed at the wafer loading / unloading ports 21, 22 and 23. The pod opener 24 includes a mounting table 25 for mounting the pod 1, and a cap attaching / detaching mechanism 26 for mounting and removing the cap of the pod 1 mounted on the mounting table 25. The pod opener 24 is mounted on the mounting table 25. By removing the cap of the pod 1 by the cap attaching / detaching mechanism 26, the wafer loading / unloading opening of the pod 1 is opened and closed. The pod 1 is supplied to and discharged from the mounting table 25 of the pod opener 24 by an in-process transfer device (RGV).

  As shown in FIG. 18, among the seven side walls of the negative pressure transfer chamber casing 12, two side walls (rear walls) located on the opposite side of the positive pressure transfer chamber 16 have process modules. The first processing unit (TiN film forming unit) 31 and the second processing unit (Ni film forming unit) 32 are connected adjacently. The first processing unit 31 and the second processing unit 32 are configured similarly to the substrate processing apparatus in the above-described embodiment. The first processing unit 31 is provided with a first raw material supply system and a reactive gas supply system, but is not provided with a second raw material supply system, and the second processing unit 32 has a second raw material supply system. Although different from the above-described embodiment, the first raw material supply system and the reactive gas supply system are not provided.

  A gate valve 44 is installed between the first processing unit 31 and the negative pressure transfer chamber 11. A gate valve 118 is installed between the second processing unit 32 and the negative pressure transfer chamber 11. Of the seven side walls in the negative pressure transfer chamber housing 12, the other two side walls on the positive pressure transfer chamber 16 side are provided with a first cooling unit 35 and a second cooling unit 36 as cooling stages. Are connected to each other, and these are configured as a cooling chamber for cooling the processed wafer 200.

  The cluster apparatus 10 includes a main controller 37 that comprehensively controls the substrate processing flow. The main controller 37 controls the operation of each unit constituting the cluster device 10.

Next, a metal film having a laminated structure of a TiN film and a Ni film is formed on a TiO ₂ film formed in advance on the wafer 200 using the cluster apparatus 10 having the above-described configuration, and a predetermined film A process of forming a thick TiN film (TiN cap film) will be described. In the following description, the operation of each part constituting the cluster device 10 is controlled by the main controller 37.

  The cap of the pod 1 mounted on the mounting table 25 of the cluster apparatus 10 is removed by the cap attaching / detaching mechanism 26, and the wafer loading / unloading port of the pod 1 is opened. When the pod 1 is opened, the positive pressure transfer machine 19 installed in the positive pressure transfer chamber 16 picks up the wafers 200 from the pod 1 one by one through the wafer carry-in / out port and puts them into the carry-in chamber 14. Then, place it on the temporary storage stand for the loading room. During this transfer operation, the positive pressure transfer chamber 16 side of the carry-in chamber 14 is opened by the gate valve 17A, and the negative pressure transfer chamber 11 side of the carry-in chamber 14 is closed by the gate valve 17B. The pressure in the negative pressure transfer chamber 11 is maintained at 100 Pa, for example.

  The positive pressure transfer chamber 16 side of the carry-in chamber 14 is closed by the gate valve 17A, and the carry-in chamber 14 is exhausted to a negative pressure by the exhaust device. When the inside of the carry-in chamber 14 is depressurized to a preset pressure value, the negative pressure transfer chamber 11 side of the carry-in chamber 14 is opened by the gate valve 17B. Next, the negative pressure transfer machine 13 in the negative pressure transfer chamber 11 picks up the wafers 200 one by one from the temporary placement table for the loading chamber and loads the wafers 200 into the negative pressure transfer chamber 11. Thereafter, the negative pressure transfer chamber 11 side of the carry-in chamber 14 is closed by the gate valve 17B.

Subsequently, the gate valve 44 of the first processing unit 31 is opened, and the negative pressure transfer machine 13 loads the wafer 200 into the processing chamber of the first processing unit 31 (wafer load). Note that when the wafer 200 is loaded into the processing chamber, since the loading chamber 14 and the negative pressure transfer chamber 11 are evacuated in advance, oxygen and moisture can be reliably prevented from entering the processing chamber. . Then, a TiN film is formed on the TiO ₂ film previously formed on the wafer 200 by the same procedure as the pressure adjustment process (S3) to the TiN film formation process (S5) in the above-described embodiment. Thereafter, the wafer 200 after the TiN film having a predetermined film thickness is carried out from the processing chamber of the first processing unit 31 into the negative pressure transfer chamber 11 by a procedure reverse to the above-described procedure.

  Subsequently, the gate valve 118 of the second processing unit 32 is opened, and the negative pressure transfer machine 13 loads the wafer 200 into the processing chamber of the second processing unit 32 (wafer load). Note that when the wafer 200 is loaded into the processing chamber, since the loading chamber 14 and the negative pressure transfer chamber 11 are evacuated in advance, oxygen and moisture can be reliably prevented from entering the processing chamber. . Then, a Ni film is formed on the TiN film formed in the first processing unit 31 by the same procedure as the pressure adjustment process (S6) to the TiN film formation process (S8) in the above-described embodiment. Thereafter, the wafer 200 after the Ni film having a predetermined film thickness is carried out from the processing chamber of the second processing unit 32 into the negative pressure transfer chamber 11 by a procedure reverse to the above-described procedure.

Then, according to the same procedure as the predetermined number of steps (S9) in the above-described embodiment, the formation of the TiN film by the first processing unit 31 and the formation of the Ni film by the second processing unit 32 are set as one cycle. Is performed a predetermined number of times to form a metal film having a laminated structure of a TiN film and a Ni film on a TiO ₂ film formed in advance on the wafer 200.

  Subsequently, the gate valve 44 of the first processing unit 31 is opened, and the negative pressure transfer machine 13 loads the wafer 200 into the processing chamber of the first processing unit 31 (wafer load). Then, a TiN film (TiN film) having a predetermined film thickness is formed on the film having a laminated structure of the TiN film and the Ni film by the same procedure as the pressure adjustment process (S10) to the TiN cap formation process (S12) in the above-described embodiment. Cap film). Thereafter, the wafer 200 after the TiN film having a predetermined film thickness is carried out from the processing chamber of the first processing unit 31 into the negative pressure transfer chamber 11 by a procedure reverse to the above-described procedure.

  Thereafter, the negative pressure transfer chamber 11 side of the unloading chamber 15 is opened by the gate valve 18B, and the negative pressure transfer machine 13 transfers the wafer 200 from the negative pressure transfer chamber 11 to the unloading chamber 15, and the unloading chamber 15 is unloaded. Transfer on the temporary table. In this case, the positive pressure transfer chamber 16 side of the carry-out chamber 15 is closed by the gate valve 18A in advance, and the carry-out chamber 15 is exhausted to a negative pressure by the exhaust device. When the unloading chamber 15 is depressurized to a preset pressure value, the negative pressure transfer chamber 11 side of the unloading chamber 15 is opened by the gate valve 18B, and the wafer 200 is unloaded. After unloading the wafer 200, the gate valve 18B is closed.

  By repeating the above operation, the above-described steps are sequentially performed on the 25 wafers 200 that are collectively loaded into the loading chamber 14. When a series of predetermined processes are completed for the 25 wafers 200, the processed wafers 200 are stored on the temporary placement table in the carry-out chamber 15.

  Thereafter, nitrogen gas is supplied into the carry-out chamber 15 maintained at a negative pressure, and after the inside of the carry-out chamber 15 reaches atmospheric pressure, the positive pressure transfer chamber 16 side of the carry-out chamber 15 is opened by the gate valve 18A. Next, the cap of the empty pod 1 placed on the placing table 25 is opened by the cap attaching / detaching mechanism 26 of the pod opener 24. Subsequently, the positive pressure transfer machine 19 in the positive pressure transfer chamber 16 picks up the wafer 200 from the carry-out chamber 15 and carries it out to the positive pressure transfer chamber 16, and passes through the wafer loading / unloading port 23 in the positive pressure transfer chamber 16. Store it in pod 1. When the storage of the 25 processed wafers 200 into the pod 1 is completed, the cap of the pod 1 is attached to the wafer loading / unloading port by the cap attaching / detaching mechanism 26 of the pod opener 24 and the pod 1 is closed.

  Even when the cluster apparatus according to the present embodiment is used, the same process as the substrate processing process according to the above-described embodiment can be performed, and the same effect as in the above-described embodiment can be obtained. When the processing conditions (particularly the processing temperature) when forming the first metal film and the processing conditions (particularly the processing temperature) when forming the second metal film are different, respectively, as in this embodiment These metal films may be formed separately in different processing chambers.

The gate electrode manufacturing process includes a gate first process in which a source / drain diffusion layer is formed after the gate electrode is formed by annealing at about 1000 ° C., that is, activation annealing (spike annealing), and the source / drain diffusion layer. There is a gate last process in which is formed before the gate electrode is formed. In the case of the gate first process, the gate electrode is heated to a temperature of about 1000 ° C. during the activation annealing, and the TiN film has no oxidation resistance in the temperature range of about 1000 ° C. It can be said that application to the gate first process is difficult. In contrast, in the case of the gate last process, the gate electrode is not heated to a temperature of about 100 ° C., and the TiN film has oxidation resistance in the temperature region in the process after the formation of the gate electrode. Can be suitably applied to the gate last process. That is, the present invention can be suitably applied when forming a gate electrode by a gate last process. In the DRAM manufacturing process, after the capacitor electrode is formed, an annealing process at about 400 ° C. is performed in an H ₂ gas atmosphere. In the DRA manufacturing process, the capacitor electrode is heated up to a temperature of about 400 ° C. at the maximum. Under such temperature conditions, TiN has higher oxidation resistance than Ni. That is, the present invention can be suitably applied when forming a capacitor electrode of a DRAM.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

  According to one embodiment of the present invention, an insulating film formed over a substrate, and a metal film provided adjacent to the insulating film, the metal film includes a first metal film and a second metal film. The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film is higher than 4.8 eV. A semiconductor device is provided which is made of a material different from the first metal film having a high work function, and the first metal film is provided between the second metal film and the insulating film. .

  Preferably, the metal film is formed on the insulating film, and the first metal film is also provided on the outermost surface of the metal film.

  Preferably, the metal film has a structure in which a stack of the first metal film and the second metal film is repeated.

  Preferably, the thickness of the first metal film is not less than 0.2 nm and not more than 4 nm.

  Preferably, the thickness of the second metal film is not less than 0.5 nm and not more than 10 nm.

  Preferably, the thickness of the second metal film is 4 nm or more and 5 nm or less.

  Preferably, the second metal film is thicker than the first metal film.

  Preferably, the first metal film is a titanium nitride film, a tantalum nitride film, an aluminum titanium nitride film, or an aluminum tantalum nitride film.

  Preferably, the second metal film is a non-noble metal.

  Preferably, the second metal film is a nickel film, a cobalt film, a beryllium film, a carbon film, a selenium film, a tellurium film, or a rhenium film.

  Preferably, the insulating film is a high dielectric constant insulating film.

  Preferably, the insulating film is a hafnium oxide film, a zirconium oxide film, an aluminum-doped hafnium oxide film, an aluminum-doped zirconium oxide film, a titanium oxide film, a niobium oxide film, a tantalum oxide film, or strontium titanate. A film, a barium strontium titanate film, or a lead zirconate titanate film.

  According to another aspect of the present invention, an insulating film is formed on a substrate, and a metal film having a laminated structure of a first metal film and a second metal film is formed adjacent to the insulating film. The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film has a work function higher than 4.8 eV. The first metal film is made of a material different from the first metal film, and in the step of forming the metal film, the first metal film is positioned between the second metal film and the insulating film. A method of manufacturing a semiconductor device for forming one metal film is provided.

  According to still another aspect of the present invention, a processing chamber for processing a substrate, a first processing gas supply system for supplying a first processing gas for forming a first metal film into the processing chamber, A second process gas supply system for supplying a second process gas for forming a second metal film in the process chamber, and a control for controlling the first process gas supply system and the second process gas supply system The first metal film is made of a material having higher oxidation resistance than the second metal film, and the second metal film has a work function higher than 4.8 eV. The control unit is made of a material different from the first metal film, and the control unit is formed on the substrate by supplying the first processing gas and the second processing gas into the processing chamber containing the substrate. Forming a metal film having a laminated structure of the first metal film and the second metal film adjacent to the insulating film. In addition, the first process gas supply system and the first metal film are formed so as to form the first metal film so that the first metal film is located between the second metal film and the insulating film. A substrate processing apparatus for controlling the processing gas supply system 2 is provided.

  According to still another aspect of the present invention, a first processing chamber for processing a substrate, and a first processing for supplying a first processing gas for forming a first metal film into the first processing chamber. A gas supply system; a second processing chamber for processing a substrate; a second processing gas supply system for supplying a second processing gas for forming a second metal film in the second processing chamber; A transfer chamber provided between the first process chamber and the second process chamber for transferring the substrate, and a substrate provided between the first process chamber and the second process chamber provided in the transfer chamber. And a control unit for controlling the first processing gas supply system, the second processing gas supply system, and the transfer robot, and the first metal film is the second metal film. The second metal film has a work function higher than 4.8 eV, and is made of a material having higher oxidation resistance than the metal film. The first metal film is made of a material different from the first metal film, and the controller transfers the substrate into the first processing chamber, supplies the first processing gas, and the substrate into the second chamber. And supplying the second processing gas to form a metal film having a laminated structure of a first metal film and a second metal film adjacent to the insulating film formed on the substrate. The first processing gas supply system, the second metal film, and the second processing gas supply system, so as to form the first metal film so that the first metal film is located between the second metal film and the insulating film. A substrate processing apparatus for controlling the processing gas supply system and the transfer robot is provided.

200 wafer (substrate)
201 processing chamber 202 processing vessel 203 support stand 206 heater 213a first source gas supply pipe 213b second source gas supply pipe 213c reaction gas supply pipe 213d purge gas supply pipe 213e purge gas supply pipe 237a first carrier gas supply pipe 237b second carrier gas Supply pipe 220a First bubbler 220b Second bubbler 280 Controller

Claims (6)

By alternately repeating the formation of the metal nitride film and the formation of the metal film, a structure in which the metal nitride film and the metal film are stacked on the insulating film formed on the surface of the substrate is provided. Forming a metal-containing film,
The metal nitride film is made of a material having higher oxidation resistance than the metal film,
The metal film is made of a material having a higher work function than the metal nitride film,
In the step of forming the metal-containing film, a semiconductor device manufacturing method in which the metal nitride film is first formed.   In the step of forming the metal-containing film, in the portion where the metal-containing film is adjacent to the insulating film, the metal nitride film is in contact with both the metal film and the insulating film, and the metal film and the insulating film The method of manufacturing a semiconductor device according to claim 1, wherein the metal nitride film is first formed so as to be positioned between the two.   The method for manufacturing a semiconductor device according to claim 1, wherein in the step of forming the metal-containing film, the metal nitride film is finally formed.   4. The semiconductor device according to claim 1, wherein in the step of forming the metal-containing film, the metal nitride film is finally formed so that the metal nitride film is provided on the outermost surface of the metal-containing film. Production method. A processing chamber for processing a substrate having an insulating film formed on the surface;
A first processing gas supply system for supplying a first processing gas for forming a metal nitride film into the processing chamber;
A second processing gas supply system for supplying a second processing gas for forming a metal film into the processing chamber;
A controller that controls the first process gas supply system and the second process gas supply system,
The metal nitride film is made of a material having higher oxidation resistance than the metal film,
The metal film is made of a material having a higher work function than the metal nitride film,
The controller supplies the first processing gas and the second processing gas into the processing chamber containing the substrate to alternately form the metal nitride film and the metal film. Repeatedly performing the process of forming a metal-containing film having a structure in which the metal nitride film and the metal film are repeatedly stacked on the insulating film formed on the surface of the substrate. A substrate processing apparatus configured to control the first processing gas supply system and the second processing gas supply system so as to form the metal nitride film first. An insulating film formed on the substrate;
A metal-containing film provided on the insulating film,
The metal-containing film has a structure in which a lamination of a metal nitride film and a metal film is repeated,
The metal nitride film is made of a material having higher oxidation resistance than the metal film,
The metal film is made of a material having a higher work function than the metal nitride film,
In a portion where the metal-containing film is adjacent to the insulating film, the metal nitride film is provided so as to be positioned between the metal film and the insulating film while being in contact with both the metal film and the insulating film. Semiconductor device.