JP2012062502A - Method for manufacturing semiconductor device and substrate processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device including a metal film having a necessary work function and oxidation resistance at low cost.SOLUTION: This method for manufacturing a semiconductor device includes the steps of: carrying in a substrate into a treatment container; performing treatment of forming a metal film with a predetermined film thickness on the substrate by supplying and exhausting processing gas into and from the treatment container; and taking out the processed substrate from the treatment container. In the step of performing treatment, during forming the metal film or after forming the metal film, oxygen-containing gas and/or nitrogen-containing gas is activated with heat or plasma, and supplied and exhausted into and from the treatment container, thereby a bottom face or surface of the metal film is modified into a conductive metal oxide layer, a conductive metal nitride layer or a conductive metal oxynitride layer.

Description

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

With the high integration and high performance of MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), application of a high dielectric constant insulating film to a gate insulating film has been studied. In a DRAM capacitor, a high dielectric constant insulating film such as an HfO ₂ film or a ZrO ₂ film is used, and from the 32 nm generation onward, adoption of an SrTiO film or TiO film having a higher dielectric constant has been studied. As an electrode material, the use of a metal film has been studied from the viewpoint of resistivity and the like.

Since the band gap of a high dielectric constant insulating film having a dielectric constant exceeding 50, such as a TiO ₂ film or SrTiO film, is narrow, there is a concern about an increase in leakage current. In order to solve the problem, it is desirable to use a metal material having a high work function of 5.0 eV or more as the electrode material. However, when Pt, which is promising as a metal material having a high work function, is used as an electrode material, there are problems such as that the material is expensive and film formation is very difficult, and it has not yet been put into practical use. It is. In addition, other metal materials having a large work function, such as Ni and Co, are easily oxidized, which may lead to an increase in EOT (equivalent oxide film thickness).

  Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device and a substrate processing apparatus provided with a metal film having a work function and oxidation resistance required at low cost.

  According to one aspect of the present invention, a process of carrying a substrate into a processing container and a process of forming a metal film having a predetermined thickness on the substrate by supplying and exhausting a processing gas into the processing container. And a step of carrying out the processed substrate from the processing container. In the step of performing the processing, oxygen is introduced into the processing container during or after the metal film is formed. By activating and supplying the contained gas and / or nitrogen-containing gas with heat or plasma and exhausting, the bottom surface or the surface of the metal film is formed into a conductive metal oxide layer, a conductive metal nitride layer, or a conductive metal acid. A method of manufacturing a semiconductor device that is modified into a nitride layer is provided.

  According to another aspect of the present invention, a processing container that accommodates a substrate, a processing gas supply system that supplies a processing gas into the processing container, and an oxygen-containing gas and / or a nitrogen-containing gas are activated by heat or plasma. A reactive gas supply system to be supplied, an exhaust system for exhausting the inside of the processing container, and supplying and exhausting a processing gas into the processing container containing the substrate, thereby forming a metal film having a predetermined thickness on the substrate. While performing the forming process, during the formation of the metal film or after forming the metal film, the oxygen-containing gas and / or the nitrogen-containing gas is activated and supplied by heat or plasma into the processing container As a result, the processing gas supply system, the reaction gas supply, and the like are modified so that the bottom surface or the surface of the metal film is modified into a conductive metal oxide layer, a conductive metal nitride layer, or a conductive metal oxynitride layer. The substrate processing apparatus is provided, characterized in that it comprises a system and a control unit for controlling the exhaust system, the.

  According to the method for manufacturing a semiconductor device and the substrate processing apparatus 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.

It is a block diagram of the gas supply system of the substrate processing apparatus which concerns on one Embodiment of this invention. It is a section lineblock diagram at the time of wafer processing of a substrate processing device concerning one embodiment of the present invention. It is a section lineblock diagram at the time of wafer conveyance of a substrate processing device concerning one embodiment of the present invention. (A) It is a flowchart of the manufacturing process of the conventional capacitor structure, (b) is a cross-sectional block diagram of the capacitor structure manufactured by the flow concerned. (A) It is a flowchart of the manufacturing process of the capacitor structure which concerns on one Embodiment of this invention, (b) is a cross-sectional block diagram of the capacitor structure manufactured by the flow concerned. (A) It is a flowchart of the manufacturing process of the capacitor structure which concerns on other embodiment of this invention, (b) is a cross-sectional block diagram of the capacitor structure manufactured by the said flow. (A) It is a flowchart of the formation process of the lower electrode which concerns on one Embodiment of this invention, (b) is a flowchart of the formation process of the upper electrode which concerns on one Embodiment of this invention. (A) It is a flowchart of the formation process of the lower electrode which concerns on other embodiment of this invention, (b) is a flowchart of the formation process of the upper electrode which concerns on other embodiment of this invention. (A) is the schematic which shows the energy level of the capacitor electrode which concerns on one Embodiment of this invention, (b) is the schematic which shows the energy level of the conventional capacitor electrode which consists of a single layer of W film | membrane. . 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 the line AA.

<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. 2 is a cross-sectional configuration diagram of the substrate processing apparatus 40 according to an embodiment of the present invention during wafer processing, and FIG. 3 is a cross-sectional configuration of the substrate processing apparatus 40 according to an embodiment of the present invention during wafer transfer. FIG.

(Processing room)
As shown in FIGS. 2 and 3, the substrate processing apparatus 40 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. 3 (wafer transfer position) when the wafer 200 is transferred, and is raised to the position shown in FIG. 2 (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. 3, the upper end portion of the lift pins 208b protrudes 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, the lift pins 208b are buried from the upper surface of the susceptor 217 as shown in FIG. 2, so that 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 44. By opening the gate valve 44, the inside of the processing chamber 201 and the inside of the negative pressure transfer chamber 11 are communicated with each other. The negative pressure transfer chamber 11 is formed in a transfer container (sealed container) 12, and a negative pressure transfer machine 13 for transferring the wafer 200 is provided in the negative pressure transfer chamber 11. The negative pressure transfer machine 13 is provided with a transfer arm 13 a that supports the wafer 200 when the wafer 200 is transferred. With the support table 203 lowered to the wafer transfer position, the gate valve 44 is opened to transfer the wafer 200 between the processing chamber 201 and the negative pressure transfer chamber 11 by the negative pressure transfer machine 13. It is possible. The wafer 200 transferred into the processing chamber 201 is temporarily placed on the lift pins 208b as described above. A load lock chamber (not shown) is provided on the opposite side of the negative pressure transfer chamber 11 from the side where the wafer transfer port 250 is provided, and the negative pressure transfer machine 13 and the negative pressure transfer chamber 13 The wafer 200 can be transferred to and from the chamber 11. 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.

  Next, the configuration of the gas supply system connected to the gas inlet 210 described above will be described with reference to FIG. FIG. 1 is a configuration diagram of a gas supply system (gas supply line) included in the substrate processing apparatus 40 according to the present embodiment.

  The gas supply system of the substrate processing apparatus 40 according to the present embodiment includes a bubbler 220a as a vaporization unit that vaporizes a liquid material containing tungsten (W) that is in a liquid state at room temperature, and the liquid material is vaporized by the bubbler 220a. A raw material gas supply system that supplies the raw material gas obtained into the processing chamber 201, a nitrogen-containing gas supply system that supplies a nitrogen-containing gas into the processing chamber 201, and an oxygen-containing material that supplies an oxygen-containing gas into the processing chamber 201 A gas supply system, a silicon-containing gas supply system that supplies a silicon-containing gas into the processing chamber 201, and a purge gas supply system that supplies a purge gas into the processing chamber 201 are provided. Furthermore, the substrate processing apparatus according to the embodiment of the present invention has a vent (bypass) system that exhausts the processing chamber 201 without bypassing the source gas from the bubbler 220a into the processing chamber 201. Below, the structure of each part is demonstrated.

(Bubbler)
Outside the processing chamber 201, a bubbler 220a is provided as a raw material container for storing a liquid raw material. The bubbler 220a is configured as a tank (sealed container) capable of containing (filling) a liquid source therein, and is also configured as a vaporizing unit that generates a source gas by vaporizing the liquid source by bubbling. A sub-heater 206a for heating the bubbler 220a and the liquid material inside is provided around the bubbler 220a. As the raw material, for example, tungsten hexafluoride (WF ₆ ), which is a metal liquid raw material containing a tungsten (W) element, is used.

A carrier gas supply pipe 237a is connected to the bubbler 220a. A carrier gas supply source (not shown) is connected to the upstream end of the carrier gas supply pipe 237a. Further, the downstream end of the carrier gas supply pipe 237a is immersed in the liquid raw material accommodated in the bubbler 220a. The 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. As the carrier gas, a gas that does not react with the liquid raw material is preferably used. For example, an inert gas such as N ₂ gas, Ar gas, or He gas is preferably used. A carrier gas supply system (carrier gas supply line) is mainly configured by the carrier gas supply pipe 237a, the MFC 222a, and the valves va1 and va2.

With the above configuration, by opening the valves va1 and va2 and supplying the carrier gas whose flow rate is controlled by the MFC 222a from the carrier gas supply pipe 237a into the bubbler 220a, the liquid raw material stored in the bubbler 220a is vaporized by bubbling. It is possible to generate a raw material gas (WF ₆ gas) as a processing gas.

(Raw gas supply system)
A raw material gas supply pipe 213a for supplying the raw material gas generated in the bubbler 220a into the processing chamber 201 is connected to the bubbler 220a. The upstream end of the source gas supply pipe 213a communicates with the space existing above the bubbler 220a. The downstream end of the source gas supply pipe 213a is connected to the gas inlet 210. The 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 source gas from the bubbler 220a into the 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 source gas from the source gas supply pipe 213a into the processing chamber 201, and is provided in the vicinity of the gas inlet 210. The valve va3 and a valve ve3 described later are configured as a highly durable high-speed gas valve. 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. The valve ve3 is a valve that controls the introduction of purge gas for purging the inside of the processing chamber 201 after purging the space between the valve va3 of the source gas supply pipe 213a and the gas inlet 210 at high speed.

  With the above configuration, it is possible to supply the source gas from the source gas supply pipe 213a into the processing chamber 201 by opening the valves va5 and va3 while vaporizing the liquid source in the bubbler 220a. Become. A source gas supply system (source gas supply line) is mainly configured by the source gas supply pipe 213a and the valves va5 and va3.

  Further, a raw material supply system (raw material supply line) is mainly configured by the carrier gas supply system, the bubbler 220a, and the raw material gas supply system.

(Nitrogen-containing gas supply system)
Further, a nitrogen-containing gas supply source 220b for supplying a nitrogen-containing gas (nitriding source) is provided outside the processing chamber 201. The upstream end of the nitrogen-containing gas supply pipe 213b is connected to the nitrogen-containing gas supply source 220b. The downstream end of the nitrogen-containing gas supply pipe 213b is connected to the gas inlet 210 through a valve vb3. The nitrogen-containing gas supply pipe 213b is provided with a mass flow controller (MFC) 222b as a flow rate controller for controlling the supply flow rate of the nitrogen-containing gas, and valves vb1, vb2, and vb3 for controlling the supply of the nitrogen-containing gas. . As the nitrogen-containing gas, for example, ammonia (NH ₃ ) gas, hydrazine (N ₂ H ₄ ) gas, N ₃ H ₈ gas, or the like is used. In this embodiment, for example, ammonia (NH ₃ ) gas is used. It is done. A nitrogen-containing gas supply system (nitrogen-containing gas supply line) is mainly configured by the nitrogen-containing gas supply source 220b, the nitrogen-containing gas supply pipe 213b, the MFC 222b, and the valves vb1, vb2, and vb3.

(Oxygen-containing gas supply system)
Further, an oxygen-containing gas supply source 220g for supplying an oxygen-containing gas (oxidation source) is provided outside the processing chamber 201. An upstream end of an oxygen-containing gas supply pipe 213g is connected to the oxygen-containing gas supply source 220g. The downstream end of the oxygen-containing gas supply pipe 213g is connected to the gas inlet 210 through a valve vg3. The oxygen-containing gas supply pipe 213g is provided with a mass flow controller (MFC) 222g as a flow rate controller for controlling the supply flow rate of the oxygen-containing gas, and valves vg1, vg2, and vg3 for controlling the supply of the oxygen-containing gas. . As the oxygen-containing gas, for example, oxygen (O ₂ ) gas, ozone (O ₃ ) gas, water vapor (H ₂ O), or the like is used. In this embodiment, for example, O ₂ gas is used. An oxygen-containing gas supply system (oxygen-containing gas supply line) is mainly configured by the oxygen-containing gas supply source 220g, the oxygen-containing gas supply pipe 213g, the MFC 222g, and the valves vg1, vg2, and vg3.

(Silicon-containing gas supply system)
In addition, a silicon-containing gas supply source 220 h that supplies a silicon-containing gas as a processing gas is provided outside the processing chamber 201. An upstream end portion of the silicon-containing gas supply pipe 213h is connected to the silicon-containing gas supply source 220h. The downstream end of the silicon-containing gas supply pipe 213h is connected to the gas inlet 210 through a valve vh3. The silicon-containing gas supply pipe 213h is provided with a mass flow controller (MFC) 222h as a flow rate controller for controlling the supply flow rate of the silicon-containing gas, and valves vh1, vh2, and vh3 for controlling the supply of hydrogen gas. As the silicon-containing gas, for example, monosilane (SiH ₄ ), disilane (Si ₂ H ₆ ), or the like is used. In the present embodiment, for example, disilane gas is used. A silicon-containing gas supply system (silicon-containing gas supply line) is mainly configured by the silicon-containing gas supply source 220h, the silicon-containing gas supply pipe 213h, the MFC 222h, and the valves vh1, vh2, and vh3.

  A processing gas supply system (processing gas supply line) for supplying a raw material gas and a silicon-containing gas as processing gases into the processing vessel is mainly configured by the raw material supply system and the silicon-containing gas supply system. In addition, a reactive gas supply system (reactive gas supply line) that supplies nitrogen-containing gas and oxygen-containing gas activated by heat or plasma into the processing vessel mainly by a nitrogen-containing gas supply system and an oxygen-containing gas supply system. Composed.

(Purge gas supply system)
Further, purge gas supply sources 220 c and 220 e for supplying a purge gas are provided outside the processing chamber 201. The upstream ends of the purge gas supply pipes 213c and 213e are connected to the purge gas supply sources 220c and 220e, respectively. The downstream end of the purge gas supply pipe 213c is connected to the gas inlet 210 through the valve vc3. The downstream end of the purge gas supply pipe 213e joins the portion between the valve va3 and the gas inlet 210 of the source gas supply pipe 213a via the valve ve3 and is connected to the gas inlet 210. The purge gas supply pipes 213c and 213e include mass flow controllers (MFC) 222c and 222e as flow rate controllers for controlling the supply flow rate of the purge gas, valves vc1, vc2, vc3, ve1, ve2, and ve3 for controlling the supply of the purge gas. , Are provided respectively. As the purge gas, for example, an inert gas such as N ₂ gas, Ar gas, or He gas is used. A purge gas supply system (purge gas supply line) is mainly configured by the purge gas supply sources 220c and 220e, the purge gas supply pipes 213c and 213e, the MFCs 222c and 222e, and the valves vc1, vc2, vc3, ve1, ve2, and ve3.

<Vent (bypass) system>
The upstream end of the vent pipe 215a is connected to the upstream side of the valve va3 of the source gas supply pipe 213a. Further, the downstream end of the vent pipe 215 a is connected to the downstream side of the pressure regulator 262 of the exhaust pipe 261 and to the upstream side of the raw material recovery trap 263. The vent pipe 215a is provided with a valve va4 that controls the flow of gas.

  With the above configuration, by closing the valve va3 and opening the valve va4, the process chamber 201 is bypassed through the vent pipe 215a without supplying the gas flowing in the source gas supply pipe 213a into the process chamber 201, Exhaust from the exhaust pipe 261 becomes possible. A vent system (vent line) is mainly configured by the vent pipe 215a and the valve va4.

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

(Control part)
The substrate processing apparatus according to the present embodiment includes a controller 280 as a control unit that controls the operation of each unit of the substrate processing apparatus. The controller 280 includes a gate valve 44, a lifting mechanism 207b, a negative pressure transfer device 11, a heater 206, a sub heater 206a, a pressure regulator (APC) 262, a vacuum pump 264, valves va1 to va5, vb1 to vb3, vc1 to vc3. Controls the operations of ve1 to ve3, vg1 to vg3, vh1 to vh3, mass flow controllers 222a, 222b, 222c, 222e, 222g, and 222h.

(2) Substrate Processing Step Next, a substrate processing step for forming a capacitor structure (MIM: Metal Insulator Metal structure) on the wafer 200 as one step of the semiconductor device manufacturing process will be described. FIG. 5A is a flowchart of a manufacturing process of a capacitor structure according to an embodiment of the present invention, and FIG. 5B is a cross-sectional configuration diagram of the capacitor structure manufactured by the flow.

  In this specification, the term metal film means a film made of a conductive substance containing a metal atom, and includes a conductive single metal film made of a single metal. Also included are conductive metal nitride films, conductive metal oxide films, conductive metal oxynitride films, conductive metal composite films, conductive metal alloy films, conductive metal silicide films, and the like. The tungsten (W) film is a conductive single metal film composed of a single metal, the tungsten nitride (WN) film is a conductive metal nitride film, and the tungsten oxide (WO) film is a conductive metal. It is an oxide film, and the tungsten oxynitride (WON) film is a conductive metal oxynitride film. Note that the WON film has a lower resistivity than the WO film, and can flow electrons at a high speed.

  As shown in FIG. 5A, first, using the above-described substrate processing apparatus 40, a processing gas is supplied and exhausted into a processing container in which a wafer 200 as a substrate is carried, whereby a lower electrode is formed on the wafer 200. That is, a process of forming a W film having a predetermined thickness as a conductive metal film is performed (Bottom Electrode formation).

In the step of performing the process of forming the W film as the lower electrode, the oxygen-containing gas and / or the nitrogen-containing gas is activated by heat in the processing container during or after the W film is formed. By supplying and exhausting, the surface of the W film (bonding surface with the HfO ₂ film described later) is changed to a WO layer that is a conductive metal oxide layer, a WN layer that is a conductive metal nitride layer, or a conductive layer. Modification to a WON layer which is a metal oxynitride layer. That is, after the step of forming the first W layer on the wafer 200 (Metal film deposition-1), the step of forming the second W layer on the first W layer (Metal film deposition-2), A step of modifying the second W layer into a WO layer, a WN layer, or a WON layer by activating and supplying and exhausting an oxygen-containing gas and / or a nitrogen-containing gas with respect to the second W layer ( O ₂ flow and / or NH ₃ flow), and this cycle is performed a predetermined number of times to form a W film as a lower electrode whose surface is modified to a WO layer, a WN layer, or a WON layer. . These processes will be described later. In the following description, a W film having a WO layer, a WN layer, or a WON layer formed on the surface is also simply referred to as a W film for convenience.

Then, a high dielectric constant insulating film, that is, a hafnium oxide film (HfO ₂ film) as a metal oxide film is formed on the W film as the lower electrode (High-k film deposition). The HfO ₂ film is formed in a processing container containing the wafer 200 under conditions where an ALD reaction occurs, for example, TDMAHf (Tetrakis-Dimethyl-Amino-Hafnium: Hf [N (CH ₃ )) as a raw material as a raw material. ₂ ] ₄ ) and the process of supplying and exhausting, and the process of supplying and exhausting, for example, H ₂ O gas as an oxidation source to the wafer 200, are performed by performing this cycle a predetermined number of times. After the HfO ₂ film having a predetermined thickness is formed, the wafer 200 is heat-treated at a temperature of about 700 ° C., for example (Post Deposition Annealing). These processes are performed using a film forming apparatus, an annealing apparatus, etc. (not shown) different from the substrate processing apparatus 40 described above.

Then, by using the above-described substrate processing apparatus 40, a processing gas is supplied and exhausted into a processing container into which the heat-treated wafer 200 is loaded, so that an upper electrode, that is, a conductive metal film is formed on the HfO ₂ film. A process of forming a W film having a predetermined thickness is performed (Top Electrode formation).

In the step of performing the process of forming the W film as the upper electrode, the oxygen-containing gas and / or the nitrogen-containing gas is activated and supplied to the processing vessel by heat and exhausted in the middle of forming the W film. The bottom surface of the W film (bonding surface with the HfO ₂ film) is formed on the WO layer that is a conductive metal oxide layer, the WN layer that is a conductive metal nitride layer, or the WON layer that is a conductive metal oxynitride layer. To reform. That is, a step of forming a third W layer on the HfO ₂ film (Metal film deposition-3) and supplying an oxygen-containing gas and / or a nitrogen-containing gas to the third W layer after being activated by heat. The step of modifying the third W layer into a WO layer, a WN layer, or a WON layer by exhausting (O ₂ flow and / or NH ₃ flow) and performing this cycle a predetermined number of times, An upper part whose bottom surface is modified to a WO layer, a WN layer, or a WON layer by performing a step (Metal film deposition-4) of forming a fourth W layer on the WO layer, the WN layer, or the WON layer. A W film as an electrode is formed. These processes will be described later.

  Hereinafter, the formation of the lower electrode (Bottom Electrode formation) and the formation of the upper electrode (Top Electrode formation) will be described in detail with reference to FIG. FIG. 7A is a flowchart of the process of forming the lower electrode according to this embodiment, and FIG. 7B is a flowchart of the process of forming the upper electrode according to this embodiment. In the following description, the operation of each part constituting the substrate processing apparatus 40 is controlled by the controller 280.

<Lower electrode formation process>
First, the formation process of the lower electrode according to this embodiment will be described with reference to FIG. 7A and FIGS.

[Substrate Loading Step (S101), Substrate Placement Step (S102)]
The lifting mechanism 207b is operated to lower the support table 203 to the wafer transfer position shown in FIG. Then, the gate valve 44 is opened, and the processing chamber 201 and the negative pressure transfer chamber 11 are communicated. Then, as described above, the negative pressure transfer machine 13 loads the wafer 200 from the negative pressure transfer chamber 11 into the processing chamber 201 while being supported by the transfer arm 13a (S101). 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 13a of the negative pressure transfer machine 13 returns from the processing chamber 201 to the negative pressure transfer chamber 11, the gate valve 44 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 (S102).

[Pressure adjustment step (S103), temperature adjustment step (S104)]
Subsequently, the pressure regulator (APC) 262 performs control so that the pressure in the processing chamber 201 becomes a predetermined processing pressure (S103). Further, the power supplied to the heater 206 is adjusted and controlled so that the surface temperature of the wafer 200 becomes a predetermined processing temperature (S104). The temperature adjustment step (S104) may be performed in parallel with the pressure adjustment step (S103).
You may make it carry out ahead of a pressure adjustment process (S103). Here, the predetermined processing temperature and processing pressure means that the W layer can be formed by the ALD method in the first W layer forming step (S105a to S105e) and the second W layer forming step (S106a to S106e) described later. Processing temperature and processing pressure. That is, the processing temperature and the processing pressure are such that the raw materials used in the first W layer formation step (S105a to S105e) and the second W layer formation step (S106a to S106e) do not self-decompose. Note that the predetermined processing temperature and processing pressure mentioned here are oxidation treatment and nitridation for the second W layer formed on the wafer 200 in the second W layer modification step (S106f, S106g) described later. It is also a processing temperature and processing pressure at which processing or oxynitriding can be performed.

In steps S101 to S104 and a substrate unloading step (S108) to be described later, while operating the vacuum pump 264, the valves va3, vb3, vg3, vh3 are closed and the valves vc1, vc2, vc3, ve1, ve2, ve3 are turned on. By opening, 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 steps S101 to S104, a raw material gas (W raw material gas) obtained by vaporizing WF ₆ as a liquid raw material (W raw material), that is, WF ₆ gas is generated (preliminary vaporization). 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 carrier gas supply pipe 237a into the bubbler 220a, the raw material contained in the bubbler 220a is evaporated by bubbling. A gas is generated (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 and exhausting the processing chamber 201 without supplying the source gas into the processing chamber 201. deep. A predetermined time is required to stably generate the source gas in the bubbler. For this reason, in this embodiment, the raw material gas is generated in advance, and the flow path of the raw material 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 source gas into the processing chamber 201 can be started or stopped quickly by switching the valve.

[First W layer forming step (S105a to S105e)]
[WF ₆ supply step (S105a)]
Subsequently, the valve va4 is closed and the valve va3 is opened, and supply of the WF ₆ gas as the raw material gas into the processing chamber 201, that is, irradiation of the wafer 200 with the WF ₆ gas is started. The source gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess source gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260. In addition, when supplying the source gas into the processing chamber 201, in order to prevent the source gas from entering the nitrogen-containing gas supply pipe 213b, the oxygen-containing gas supply pipe 213g, and the silicon-containing gas supply pipe 213h, It is preferable to keep the valves vc3 and ve3 open so that the raw material gas is diffused in the processing chamber 201, and keep N ₂ gas flowing in the processing chamber 201 at all times. When a predetermined time has elapsed after opening the valve va3 and starting the supply of the source gas, the valve va3 is closed and the valve va4 is opened to stop the supply of the source gas into the processing chamber 201.

[Purge process (S105b)]
After the valve va3 is closed and the supply of the source gas into the processing chamber 201 is stopped, the valves vc3 and ve3 are kept open, and the supply of N ₂ gas into the processing chamber 201 is continued. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this way, the inside of the processing chamber 201 is purged with N ₂ gas, and the raw material gas remaining in the processing chamber 201 is removed.

[Si ₂ H ₆ supply step (S105c)]
When the purging in the processing chamber 201 is completed, the valves vh1, vh2, and vh3 are opened to supply Si ₂ H ₆ gas as a processing gas into the processing chamber 201, that is, Si to the wafer 200. Start irradiation with ₂ H ₆ gas. The Si ₂ H ₆ gas whose flow rate is controlled by the MFC 222h is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess Si ₂ H ₆ gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260. When Si ₂ H ₆ gas is supplied into the processing chamber 201, Si ₂ H ₆ gas is prevented from entering the source gas supply pipe 213a, the nitrogen-containing gas supply pipe 213b, and the oxygen-containing gas supply pipe 213g. In order to facilitate the diffusion of Si ₂ H ₆ gas in the processing chamber 201, it is preferable to keep the valves vc 3 and ve 3 open and to constantly flow N ₂ gas into the processing chamber 201. After the valves vh1, vh2, and vh3 are opened and the supply of Si ₂ H ₆ gas is started, when a predetermined time has elapsed, the valve vh3 is closed and the supply of Si ₂ H ₆ gas into the processing chamber 201 is stopped.

[Purge process (S105d)]
After the valve vh3 is closed and the supply of the Si ₂ H ₆ gas into the processing chamber 201 is stopped, the valves vc3 and ve3 are kept open and the supply of N ₂ gas into the processing chamber 201 is continued. . The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this way, the inside of the processing chamber 201 is purged with N ₂ gas, and Si ₂ H ₆ gas and reaction byproducts remaining in the processing chamber 201 are removed.

[Predetermined number of steps (S105e)]
Then, the steps S105a to S105d are defined as one cycle, and this cycle is performed a predetermined number of times to form a first W layer having a predetermined thickness on the wafer 200.

[Second W Layer Formation Step (S106a to S106e)]
Subsequently, the WF ₆ supply step (S106a), the purge step (S106b), the Si ₂ H ₆ supply step (S106c), and the purge step (S106d) are set as one cycle, and this cycle is executed a predetermined number of times (S106e). Thus, the second W layer is formed on the first W layer. Steps 106a to S106e are performed in the same manner as the first W layer forming step (S105a to S105e) described above.

  Here, if the second W layer formed in the second W layer formation step (S106a to S106e) is too thin, it is used as an oxidation source in the second W layer modification step (S106f to S106g) described later. The first W layer is directly oxidized, nitrided, or oxynitrided by the oxygen-containing gas or the nitrogen-containing gas used as the nitriding source, and the lower electrode is excessively oxidized, nitrided, or oxynitrided. Accordingly, in the second W layer forming step (S106a to S106e), the number of executions of the cycle in the predetermined number of times execution step (S106e) is, for example, 5 times or more, and the thickness of the second W layer to be formed is, for example, 0. The thickness is preferably 5 nm or more.

  Further, if the second W layer formed in the second W layer formation step (S106a to S106e) is too thick, oxygen used as an oxidation source in the second W layer modification step (S106f to S106g) described later. Oxygen (O) atoms contained in the contained gas and nitrogen (N) atoms contained in the nitrogen-containing gas used as the nitriding source are difficult to be introduced into the entire second W layer. Accordingly, in the second W layer forming step (S106a to S106e), the number of cycles in the predetermined number of times execution step (S106e) is set to, for example, 20 times or less, and the thickness of the formed second W layer is set to, for example, 2 nm or less. It is preferable that

[Second W Layer Modification Step (S106f, S106g)]
[O ₂ and / or NH ₃ supply step (S106f)]
Subsequently, the valves vg1, vg2, vg3 and / or the valves vb1, vb2, vb3 are opened to supply the O ₂ gas and / or the NH ₃ gas into the processing chamber 201, that is, the O ₂ gas to the wafer 200 and Start irradiation with NH ₃ gas. The O ₂ gas whose flow rate is controlled by the MFC 222g and the NH ₃ gas whose flow rate is controlled by the MFC 222b are dispersed by the shower head 240, activated by heat, and uniformly supplied onto the wafer 200 in the processing chamber 201, respectively. The Excess O ₂ gas and NH ₃ gas flow through the exhaust duct 259 and are exhausted to the exhaust port 260.

When supplying O ₂ gas and / or NH ₃ gas into the processing chamber 201, in order to prevent the O ₂ gas and NH ₃ gas from entering the source gas supply pipe 213a and the silicon-containing gas supply pipe 213h, Further, it is preferable that the valves vc3 and ve3 are kept open and the N ₂ gas is always allowed to flow into the processing chamber 201 so as to promote the diffusion of O ₂ gas and NH ₃ gas in the processing chamber 201. After the valve vg1, vg2, vg3 and / or the valve vb1, vb2, vb3 are opened and the supply of O ₂ gas or NH ₃ gas is started, the valve vg3 and / or the valve vb3 are closed after a predetermined time has passed. The supply of O ₂ gas and NH ₃ gas into 201 is stopped.

Upon irradiation with activated O ₂ gas in the heat to the wafer 200, the oxygen atoms contained in the O ₂ gas is introduced into the second W layer. As a result, the second W layer is oxidized and modified to a WO layer as a conductive metal oxide layer. The underlying first W layer is not oxidized and remains the W layer. By adding oxygen atoms into the second W layer, the work function of the bonding surface (WO layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. The work function of the entire electrode can be increased.

Further, when the wafer 200 is irradiated with NH ₃ gas activated by heat, nitrogen atoms contained in the NH ₃ gas are introduced into the second W layer. As a result, the second W layer is nitrided and modified to a WN layer as a conductive metal nitride layer. Note that the underlying first W layer is not nitrided and remains the W layer. By adding nitrogen atoms into the second W layer, the work function of the bonding surface (WN layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. The work function of the entire electrode can be increased.

Further, when the wafer 200 is irradiated with heat-activated O ₂ gas and NH ₃ gas, oxygen atoms contained in the O ₂ gas and nitrogen atoms contained in the NH ₃ gas are introduced into the second W layer, respectively. . As a result, the second W layer is oxynitrided and modified to a WON layer as a conductive metal oxynitride layer. Note that the underlying first W layer remains the W layer without being oxynitrided. By adding oxygen atoms and nitrogen atoms into the second W layer, the work function of the bonding surface (WON layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. As a result, the work function of the entire lower electrode can be increased.

[Purge process (S106g)]
After the valve vg3 and / or the valve vb3 is closed and the supply of the O ₂ gas and the NH ₃ gas into the processing chamber 201 is stopped, the valves vc3 and ve3 are kept open and the N ₂ gas into the processing chamber 201 is kept open. Will continue to supply. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this way, the inside of the processing chamber 201 is purged with N ₂ gas, and O ₂ gas, NH ₃ gas, and reaction byproducts remaining in the processing chamber 201 are removed.

[Predetermined number of steps (S106h)]
The second W layer forming step (S106a to S106e) and the second W layer modifying step (
S106f and S106g) are defined as one cycle and this cycle is performed a predetermined number of times, whereby a WO layer (a layer in which the second W layer is oxidized), a WN layer (a layer in which the second W layer is oxidized), A layer in which the second W layer is nitrided) or a WON layer (a layer in which the second W layer is oxynitrided) is formed as a lower electrode. The lower electrode is formed by laminating a first W layer having a predetermined thickness and a WO layer, WN film, or WON layer having a predetermined thickness, and the surface is formed on the WO layer, WN layer, or WON layer. It is configured as a modified W film.

Note that the thickness of the WO layer, WN layer, or WON layer formed on the first W layer is preferably 0.5 nm or more and 2.0 nm or less in the thickness direction from the interface with the HfO ₂ film, for example. . When the thickness of the WO layer, WN layer, or WON layer is less than 0.5 nm, the effect of increasing the work function due to the addition of oxygen atoms or nitrogen atoms in the second W layer decreases, and oxidation, The influence of the work function of the first W layer which is not nitrided or oxynitrided becomes strong, and it becomes difficult to increase the work function of the entire lower electrode. On the other hand, when the thickness of the WO layer, WN layer, or WON layer exceeds 2.0 nm, the resistance of the lower electrode increases. If the thickness of the WO layer, WN layer, or WON layer is 2.0 nm or less, the effect of increasing the work function can be sufficiently obtained. That is, when modifying the surface of the lower electrode, it is preferable to modify only the vicinity of the interface with the HfO ₂ film.

  The oxygen concentration of the WO layer formed on the first W layer is preferably, for example, 5 atom% or more and 20 atom% or less, and more preferably 5 atom% or more and 10 atom% or less. When the oxygen concentration in the WO layer is less than 5 atom%, the effect of increasing the work function due to the addition of oxygen atoms in the second W layer is reduced, and the work function of the unoxidized first W layer is reduced. Becomes stronger, and it becomes difficult to increase the work function of the entire lower electrode. In addition, when the oxygen concentration in the WO layer exceeds 20 atom%, the surface portion of the lower electrode becomes an oxide and becomes an insulator, and EOT (equivalent oxide film thickness) also increases. If the oxygen concentration in the WO layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the oxygen concentration in the WO layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less.

  Further, the nitrogen concentration of the WN layer formed on the first W layer is preferably, for example, 5 atom% or more and 20 atom% or less, and more preferably 5 atom% or more and 10 atom% or less. If the nitrogen concentration in the WN layer is less than 5 atom%, the effect of increasing the work function due to the addition of nitrogen atoms in the second W layer is reduced, and the work function of the first non-nitrided W layer is reduced. Becomes stronger, and it becomes difficult to increase the work function of the entire lower electrode. If the nitrogen concentration in the WN layer exceeds 20 atom%, the surface portion of the lower electrode becomes nitride and becomes an insulator. If the nitrogen concentration in the WN layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the nitrogen concentration in the WN layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less.

The oxygen and nitrogen concentrations of the WON layer formed on the first W layer are preferably 5 atom% or more and 20 atom% or less, for example, and the total concentration of oxygen and nitrogen is preferably 5 atom% or more and 10 atom% or less. More preferred. If the total concentration of oxygen and nitrogen in the WON layer is less than 5 atom%, the effect of increasing the work function due to the addition of oxygen atoms and nitrogen atoms to the second W layer is reduced, and oxynitridation is not performed. The influence of the work function of the first W layer becomes strong, and it becomes difficult to increase the work function of the entire lower electrode. Further, when the nitrogen concentration in the WON layer exceeds 20 atom%, the surface portion of the lower electrode becomes oxynitride and becomes an insulator. If the total concentration of oxygen and nitrogen in the WON layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the total concentration of oxygen and nitrogen in the WON layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 or less.
Atom% or less is preferable.

Note that the thickness of the WO layer, the WN layer, or the WON layer can be controlled by adjusting the number of executions of the cycle in the predetermined number of execution steps (S106h). The oxygen concentration and nitrogen concentration of the WO layer, WN layer, or WON layer are, for example, O ₂ irradiation time, O ₂ concentration, O ₂ supply flow rate, NH ₃ irradiation time, NH ₃ concentration, NH ₃ supply flow rate, wafer temperature. It can control by adjusting etc.

As processing conditions of the wafer 200 in the first W layer forming step (S105a to S105e) and the second W layer forming step (S106a to S106e) in the present embodiment,
Wafer temperature: 100-400 ° C.
Processing chamber pressure: 0.1 to 1000 Pa,
WF ₆ supply flow rate: 1-1000 sccm,
Si ₂ H ₆ supply flow rate: 1 to 2000 sccm,
N ₂ (purge gas) supply flow rate: 10 to 10000 sccm
Is exemplified.

In addition, as a processing condition of the wafer 200 in the second W layer modification step (S106f, S106g) in the present embodiment,
Wafer temperature: 100-400 ° C.
Processing chamber pressure: 1 to 5000 Pa,
O ₂ supply flow rate: 1 to 5000 sccm,
NH ₃ supply flow rate: 1 to 5000 sccm,
N ₂ (purge gas) supply flow rate: 10 to 10000 sccm
Is exemplified.

[Residual gas removal step (S107)]
After a lower electrode (a W film whose surface has been modified to a WO layer, a WN layer, or a WON layer) is formed on the wafer 200, the processing chamber 201 is evacuated to provide valves vc1, vc2, vc3, and ve1. , Ve2 and ve3 are kept open, and the supply of N ₂ gas into the processing chamber 201 is continued. 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, 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 (S108)]
Thereafter, the wafer 200 on which the lower electrode has been formed is transferred from the processing chamber 201 to the negative pressure transfer chamber by a procedure reverse to the procedure shown in the substrate loading step (S101) and the substrate placement step (S102). 11 is carried out. Thereafter, the wafer 200 after the formation of the lower electrode is sequentially transferred to another apparatus for forming a HfO ₂ film and another apparatus for performing heat treatment.

<Formation process of upper electrode>
Then, the formation process of the upper electrode which concerns on this embodiment is demonstrated using FIG.7 (b) and FIGS. 1-3.

[Substrate Loading Step (S201) to Temperature Adjustment Step (S204)]
The wafer 200 on which the HfO ₂ film is formed on the lower electrode and further heat-treated is carried into the process chamber 201 and placed on the susceptor 217. These steps are performed in the same manner as the above-described substrate carry-in step (S101) and substrate placement step (S102).

  Subsequently, a pressure adjustment step (S203) and a temperature adjustment step (S204) are performed. These steps are performed in the same manner as the pressure adjustment step (S103) and the temperature adjustment step (S104) described above.

[Third W Layer Formation Step (S205a to S205e)]
Subsequently, the WF ₆ supply step (S205a), the purge step (S205b), the Si ₂ H ₆ supply step (S205c), and the purge step (S205d) are set as one cycle, and this cycle is executed a predetermined number of times (S205e). Thus, a third W layer having a predetermined thickness is formed on the heat-treated HfO ₂ film. Steps 205a to S205e are performed in the same manner as the above-described second W layer forming step (S105a to S105e).

[Third W Layer Modification Step (S205f, S205g)]
Subsequently, an O ₂ and / or NH ₃ supply step (S205f) is performed, and the formed third W layer is modified to a WO layer, a WN layer, or a WON layer. Thereafter, a purge step (S205g) is performed. The O ₂ and / or NH ₃ supply step (S205f) and the purge step (S205g) are performed in the same manner as the O ₂ and / or NH ₃ supply step (S106f) and the purge step (S106g).

[Predetermined number of steps (S205h)]
Subsequently, the third W layer forming step (S205a to S205e) and the third W layer modifying step (S205f, S205g) were performed as one cycle, and the heat treatment was performed by performing this cycle a predetermined number of times. On the HfO ₂ film, a WO layer (layer obtained by oxidizing the third W layer), a WN layer (layer obtained by nitriding the third W layer), or a WON layer (third W layer) having a predetermined thickness Are oxynitrided layers). The thickness, oxygen concentration, and nitrogen concentration of the WO layer, WN layer, or WON layer formed on the HfO ₂ film are the thickness of the WO layer, WN layer, or WON layer formed on the first W layer, oxygen Same as concentration and nitrogen concentration.

[Fourth W Layer Formation Step (S206a to S206e)]
Subsequently, the WF ₆ supply step (S206a), the purge step (S206b), the Si ₂ H ₆ supply step (S206c), and the purge step (S206d) are set as one cycle, and this cycle is executed a predetermined number of times (S206e). Thus, a fourth W layer having a predetermined thickness is formed on the WO layer, the WN layer, or the WON layer formed on the HfO ₂ film, and used as the upper electrode. The upper electrode is formed by laminating a WO layer, WN film, or WON layer having a predetermined thickness and a fourth W layer having a predetermined thickness, and the bottom surface is changed to a WO layer, a WN layer, or a WON layer. It is configured as a quality W film. In addition, process S206a-S206e is performed similarly to the above-mentioned 1st W layer formation process (S105a-S105e).

[Residual gas removal step (S207), substrate unloading step (S208)]
Thereafter, after performing the same process as the above-described residual gas removing process (S107) (S207), the procedure shown in the substrate loading process (S101) and the substrate placing process (S102) is reversed. The wafer 200 after the formation of the upper electrode is carried out from the processing chamber 201 into the negative pressure transfer chamber 11 (S208), and the substrate processing step according to the present embodiment is completed.

(3) Effects according to this embodiment According to this embodiment, one or more of the following effects are achieved.

(A) According to the present embodiment, the oxygen-containing gas and / or the nitrogen-containing gas is activated by heat in the processing container during or after the formation of the W film as the lower electrode and the upper electrode. By supplying and exhausting, the surface of the W film constituting the lower electrode and the bottom surface of the W film constituting the upper electrode are modified into a WO layer, a WN layer, or a WON layer, respectively. At this time, the thickness of the WO layer, WN layer, or WON layer is, for example, 0.5 n in the thickness direction from the interface with the HfO ₂ film.
m to 2.0 nm. The oxygen concentration in the WO layer is, for example, 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less, and the nitrogen concentration in the WN layer is, for example, 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less. %, And the total concentration of oxygen and nitrogen in the WON layer is, for example, not less than 5 atom% and not more than 20 atom%, preferably not less than 5 atom% and not more than 10 atom%.

Thereby, the work function of the surface (WO layer, WN layer, or WON layer) of the lower electrode joined to the HfO ₂ film as the high dielectric constant insulating film and the bottom surface (WO layer, WN layer, or WON layer) of the upper electrode Thus, the work functions of the entire lower electrode and the entire upper electrode can be increased, respectively, and for example, leakage current in the capacitor portion can be reduced. In particular, the thickness of the second W film formed in the second W layer forming step (S106a to S106e) and the thickness of the third W film formed in the third W layer forming step (S205a to S205e) are each 2 nm. By setting the following, in the second W layer modification process (S106f, S106g) and the third W layer modification process (S205f, S205g), the second W film and the third W film are included. Oxygen atoms and nitrogen atoms can be introduced reliably, and the surface of the W film as the lower electrode and the bottom surface of the W film as the upper electrode are reliably modified to the WO layer, WN layer, or WON layer, respectively. can do.

FIG. 5B is an enlarged cross-sectional view of the capacitor structure (MIM structure) according to this embodiment. As shown in the figure, the lower electrode has a laminated structure of a first W layer and a WO layer, a WN layer, or a WON layer (a layer in which the second W layer is modified), and the capacitor insulating film is HfO. _The upper electrode has a laminated structure of a WO layer, a WN layer, or a WON layer (a layer in which the third W layer is modified) and a fourth W layer. FIG. 9A is a schematic view illustrating the energy levels of the capacitor electrodes (lower electrode and upper electrode) according to this embodiment. A leakage current in a capacitor structure in which a capacitor insulating film is sandwiched between capacitor electrodes is mainly determined by a band offset (conduction band offset) between the work function of the capacitor electrode and the conduction band side of the capacitor insulating film. In general, it is desirable that the conduction band offset be higher than the voltage applied between the capacitor electrodes. According to the present embodiment, the work functions of the lower electrode and the upper electrode bonded to the HfO ₂ film are set to the work functions (4.9 eV to 5.1 eV) of the WO layer, the WN layer, and the WON layer, respectively. it can. Therefore, when the HfO ₂ film is used as the capacitor insulating film, a conduction band offset of about 2.9 to 3.1 eV can be secured, and the leakage current can be greatly reduced.

FIG. 4A is a flowchart of a manufacturing process of a conventional capacitor structure, and FIG. 4B is a cross-sectional configuration diagram of a capacitor structure (MIM structure) manufactured by the flow. As shown in the figure, the capacitor electrodes (lower electrode and upper electrode) are each composed of a single layer of W film, and the capacitor insulating film is composed of an HfO ₂ film. FIG. 9B is a schematic diagram showing energy levels of a conventional capacitor electrode (lower electrode and upper electrode) made of a single layer of W film. Since the work function of W is about 4.5 eV, when the HfO ₂ film is used as the capacitor insulating film, the conduction band offset can be secured only about 2.5 eV, which is 0.4 eV˜ There is a risk that the leakage current will increase due to a decrease of about 0.6 eV.

(B) According to the present embodiment, oxygen atoms contained in the O ₂ gas and nitrogen atoms contained in the NH ₃ gas are introduced only into the second W layer and the third W layer. The first W layer and the fourth W layer are left as W layers without being oxidized, nitrided, or oxynitrided. As a result, it is possible to prevent the entire W film forming the lower electrode and the upper electrode from being excessively oxidized, nitrided, or oxynitrided, increase the resistance value of the lower electrode and the upper electrode, and EOT (equivalent oxidation). Increase in film thickness) can be suppressed. In particular, by setting the second W layer formed in the second W layer formation step (S106a to S106e) to 0.5 nm or more, O ₂ gas or NH ₃ gas is directly supplied to the first W layer. This can be reliably prevented, and excessive oxidation of the lower electrode can be reliably avoided.

(C) According to the present embodiment, the metal film constituting the lower electrode and the upper electrode is formed using W without using a metal that is easily oxidized, such as Ni or Co. Since W is a material that is relatively difficult to oxidize, the entire W film can be prevented from being excessively oxidized, and an increase in EOT (equivalent oxide film thickness) of the lower electrode and the upper electrode can be suppressed. it can.

(D) According to the present embodiment, the metal film constituting the lower electrode and the upper electrode is made of W without using an expensive noble metal such as Au, Ag, Pt, Pd, Rh, Ir, Ru, and Os. It is formed using. Since W is a relatively inexpensive material that can be easily formed, the manufacturing cost of the semiconductor device can be reduced.

<Other Embodiments of the Present Invention>
In the above-described embodiment, the oxygen-containing gas and / or the nitrogen-containing gas is activated and supplied to the processing vessel by heat and exhausted, whereby the bottom surface or the surface of the W film is changed to the WO layer, WN layer, or WON layer. However, the present invention is not limited to such a form. That is, the above-described reforming process may be performed by supplying an oxygen-containing gas and / or a nitrogen-containing gas activated by plasma into the processing container and exhausting it.

  FIG. 6A is a flowchart of the manufacturing process of the capacitor structure according to the present embodiment, and FIG. 6B is a cross-sectional configuration diagram of the capacitor structure manufactured by the flow.

As shown in FIG. 6A, in the step of performing a process of forming a W film as a lower electrode according to the present embodiment (Bottom Electrode formation), a step of forming a first W layer on the wafer 200 (Metal). film deposition-1), oxygen-containing gas and / or nitrogen-containing gas is activated and supplied to the first W layer by plasma, and then exhausted, so that the surface of the first W layer becomes a WO layer, a WN layer, Or a step of modifying the WON layer (Plasma O ₂ and / or NH ₃ ), so that the surface has a predetermined thickness as a lower electrode whose surface is modified to a WO layer, a WN layer, or a WON layer. The point which forms W film | membrane differs from the above-mentioned embodiment.

In the step of performing the process of forming the W film as the upper electrode according to the present embodiment (Top Electrode formation), the step of forming the second W layer on the HfO ₂ film (Metal film deposition-2), A step of modifying the second W layer into a WO layer, a WN layer, or a WON layer by activating and supplying and exhausting an oxygen-containing gas and / or a nitrogen-containing gas with respect to the second W layer ( (Plasma O ₂ and / or NH ₃ ) and a step of forming a third W layer on the WO layer, WN layer, or WON layer (Metal film deposition-3), so that the bottom surface is the WO layer. The WN layer or the WON layer is different from the above-described embodiment in that a W film having a predetermined film thickness is formed as an upper electrode modified.

  Hereinafter, the formation of the lower electrode (Bottom Electrode formation) and the formation of the upper electrode (Top Electrode formation) will be described in detail with reference to FIG. FIG. 8A is a flowchart of the formation process of the lower electrode according to this embodiment, and FIG. 8B is a flowchart of the formation process of the upper electrode according to this embodiment. In the following description, the operation of each part constituting the substrate processing apparatus 40 is controlled by the controller 280.

<Lower electrode formation process>
First, the formation process of the lower electrode according to the present embodiment will be described with reference to FIG. 8A and FIGS.

[Substrate Loading Step (S301) to Temperature Adjustment Step (S304)]
The wafer 200 is carried into the processing chamber 201 and placed on the susceptor 217. These steps are performed in the same manner as the above-described substrate carry-in step (S101) and substrate placement step (S102).

  Subsequently, a pressure adjustment step (S303) and a temperature adjustment step (S304) are performed. These steps are performed in the same manner as the pressure adjustment step (S103) and the temperature adjustment step (S104) described above.

[First W layer forming step (S305a to S305e)]
Subsequently, the WF ₆ supply step (S305a), the purge step (S305b), the Si ₂ H ₆ supply step (S305c), and the purge step (S305d) are set as one cycle, and this cycle is executed a predetermined number of times (S305e). As a result, a first W layer having a predetermined thickness is formed on the wafer 200. Steps 305a to S305e are performed in the same manner as the first W layer forming step (S105a to S105e) described above.

[Plasma O ₂ and / or NH ₃ Supply Step (S306)]
Subsequently, the valves vg1, vg2, vg3 and / or the valves vb1, vb2, vb3 are opened, and the plasma-activated O ₂ gas and / or the plasma-activated NH ₃ gas into the process chamber 201 are opened. Supply, i.e. irradiation, is started. The O ₂ gas whose flow rate is controlled by the MFC 222g and the NH ₃ gas whose flow rate is controlled by the MFC 222b are dispersed by the shower head 240 and are uniformly supplied onto the wafer 200 in the processing chamber 201, respectively. Excess O ₂ gas and NH ₃ gas flow through the exhaust duct 259 and are exhausted to the exhaust port 260. The activation of O ₂ gas and NH ₃ gas is performed by a remote plasma unit (not shown) provided in the oxygen-containing gas supply pipe 213g and the nitrogen-containing gas supply pipe 213b. Further, instead of the NH ₃ gas activated by plasma, N ₂ gas activated by plasma may be supplied.

When supplying O ₂ gas and / or NH ₃ gas into the processing chamber 201, in order to prevent the O ₂ gas and NH ₃ gas from entering the source gas supply pipe 213a and the silicon-containing gas supply pipe 213h, Further, it is preferable that the valves vc3 and ve3 are kept open and the N ₂ gas is always allowed to flow into the processing chamber 201 so as to promote the diffusion of O ₂ gas and NH ₃ gas in the processing chamber 201. After the valve vg1, vg2, vg3, valve vb1, vb2, vb3 or both are opened and the supply of O ₂ gas or NH ₃ gas is started, when a predetermined time elapses, either the valve vg3, the valve vb3 or Both are closed and the supply of O ₂ gas and NH ₃ gas into the processing chamber 201 is stopped.

When the activated O ₂ gas plasma is irradiated to the wafer 200, the oxygen atoms contained in the O ₂ gas is introduced to the surface of the first W layer. As a result, the surface of the first W layer is oxidized and modified to a WO layer as a conductive metal oxide layer. Note that the region excluding the surface of the first W layer remains the W layer without being oxidized. The W film as the lower electrode is configured as a first W layer having a WO layer formed on the surface. By adding oxygen atoms to the surface of the first W layer, the work function of the bonding surface (WO layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. The work function of the entire electrode can be increased.

Further, when the wafer 200 is irradiated with NH ₃ gas activated by plasma, nitrogen atoms contained in the NH ₃ gas are introduced into the surface of the first W layer. As a result, the surface of the first W layer is nitrided and modified to a WN layer as a conductive metal nitride layer. Note that the region excluding the surface of the first W layer remains the W layer without being nitrided. The W film as the lower electrode is configured as a first W layer having a WN layer formed on the surface. By adding nitrogen atoms to the surface of the first W layer, the work function of the bonding surface (WN layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. The work function of the entire electrode can be increased.

Moreover, when the wafer 200 is irradiated with O ₂ gas and NH ₃ gas activated by plasma, oxygen atoms contained in the O ₂ gas and nitrogen atoms contained in the NH ₃ gas are introduced into the surface of the first W layer, respectively. The As a result, the surface of the first W layer is oxynitrided and modified to a WON layer as a conductive metal oxynitride layer. Note that the region excluding the surface of the first W layer remains the W layer without being oxynitrided. The W film as the lower electrode is configured as a first W layer having a WON layer formed on the surface. By adding oxygen atoms and nitrogen atoms to the surface of the first W layer, the work function of the bonding surface (WON layer) of the lower electrode bonded to the HfO ₂ film as the high dielectric constant insulating film can be increased. As a result, the work function of the entire lower electrode can be increased.

Note that the thickness (depth) of the region (WO layer, WN layer, or WON layer) in which the first W layer is oxidized, nitrided, or oxynitrided is, for example, 0 in the thickness direction from the interface with the HfO ₂ film. It is preferable that the thickness be 5 nm or more and 2.0 nm or less. When the thickness of the WO layer, WN layer, or WON layer is less than 0.5 nm, the work function increasing effect due to the addition of oxygen atoms or nitrogen atoms to the surface of the first W layer is reduced, and the surface is The influence of the work function of the excluded region (the first W layer not oxidized, nitrided, or oxynitrided) becomes strong, and it becomes difficult to increase the work function of the entire lower electrode. . On the other hand, when the thickness of the WO layer, WN layer, or WON layer exceeds 2.0 nm, the resistance of the lower electrode increases. If the thickness of the WO layer, WN layer, or WON layer is 2.0 nm or less, the effect of increasing the work function can be sufficiently obtained. That is, when modifying the surface of the lower electrode, it is preferable to modify only the vicinity of the interface with the HfO ₂ film.

  The oxygen concentration in the region (WO layer) that oxidizes the first W layer is preferably, for example, 5 atom% or more and 20 atom% or less, and more preferably 5 atom% or more and 10 atom% or less. When the oxygen concentration in the WO layer is less than 5 atom%, the effect of increasing the work function due to the addition of oxygen atoms to the surface of the first W layer is reduced, and the region excluding the surface (first non-oxidized region) is reduced. The effect of the work function of the (W layer) becomes stronger, and it becomes difficult to increase the work function of the entire lower electrode. In addition, when the oxygen concentration in the WO layer exceeds 20 atom%, the surface portion of the lower electrode becomes an oxide and becomes an insulator, and EOT (equivalent oxide film thickness) also increases. If the oxygen concentration in the WO layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the oxygen concentration in the WO layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less.

  Further, the nitrogen concentration in the region (WN layer) in which the first W layer is nitrided is preferably, for example, 5 atom% or more and 20 atom% or less, and more preferably 5 atom% or more and 10 atom% or less. When the nitrogen concentration in the WN layer is less than 5 atom%, the effect of increasing the work function due to the addition of nitrogen atoms to the surface of the first W layer is reduced, and the region excluding the surface (first non-nitrided region) is reduced. The effect of the work function of the (W layer) becomes stronger, and it becomes difficult to increase the work function of the entire lower electrode. If the nitrogen concentration in the WN layer exceeds 20 atom%, the surface portion of the lower electrode becomes nitride and becomes an insulator. If the nitrogen concentration in the WN layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the oxygen concentration in the WN layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less.

The oxygen and nitrogen concentrations in the region where the first W layer is oxynitrided (WON layer) are preferably set to a total concentration of oxygen and nitrogen of, for example, 5 atom% or more and 20 atom% or less, and 5 atom% or more and 10 atom% or less. More preferably. When the total concentration of oxygen and nitrogen in the WON layer is less than 5 atom%, the work function increasing effect due to the addition of oxygen atoms and nitrogen atoms to the surface of the first W layer decreases, and the region excluding the surface The influence of the work function of (the first W layer that is not oxynitrided) becomes strong, and it becomes difficult to increase the work function of the entire lower electrode. If the total concentration of oxygen and nitrogen in the WON layer exceeds 20 atom%, the surface portion of the lower electrode becomes an oxynitride and becomes an insulator. If the total concentration of oxygen and nitrogen in the WON layer is 10% or less, the effect of increasing the work function can be sufficiently obtained. That is, the total concentration of oxygen and nitrogen in the WON layer is 5 atom% or more and 20 atom% or less, preferably 5 atom% or more and 10 atom% or less.

The thickness (depth), oxygen concentration, and nitrogen concentration of the WO layer, WN layer, or WON layer are, for example, O ₂ irradiation time, O ₂ concentration, O ₂ supply flow rate, NH ₃ irradiation time, NH ₃ concentration, It can be controlled by adjusting the NH ₃ supply flow rate, the wafer temperature, and the like.

The processing conditions for the wafer 200 in the plasma O ₂ and / or NH ₃ supply step (S306) in the present embodiment are as follows:
Wafer temperature: 25-400 ° C.
Processing chamber pressure: 0.1 to 250 Pa,
O ₂ supply flow rate: 1 to 5000 sccm,
NH ₃ supply flow rate: 1 to 5000 sccm,
N ₂ (purge gas) supply flow rate: 10 to 10,000 sccm,
High frequency power: 50-400W
Is exemplified.

[Residual gas removal step (S307), substrate unloading step (S308)]
Thereafter, after performing the same process as the above-described residual gas removing process (S107) (S307), the procedure shown in the substrate loading process (S101) and the substrate placing process (S102) is reversed. The wafer 200 after forming the lower electrode is carried out from the processing chamber 201 into the negative pressure transfer chamber 11 (S308). Thereafter, the wafer 200 on which the lower electrode is formed is sequentially transferred to another apparatus for forming an HfO ₂ film and another apparatus for performing heat treatment.

<Formation process of upper electrode>
Then, the formation process of the upper electrode which concerns on this embodiment is demonstrated using FIG.8 (b) and FIGS. 1-3.

[Substrate Loading Step (S401) to Temperature Adjustment Step (S404)]
The wafer 200 on which the HfO ₂ film is formed on the lower electrode and further heat-treated is carried into the process chamber 201 and placed on the susceptor 217. These steps are performed in the same manner as the above-described substrate carry-in step (S101) and substrate placement step (S102).

  Subsequently, a pressure adjustment step (S403) and a temperature adjustment step (S404) are performed. These steps are performed in the same manner as the pressure adjustment step (S103) and the temperature adjustment step (S104) described above.

[Second W Layer Formation Step (S405a to S405e)]
Subsequently, the WF ₆ supply step (S405a), the purge step (S405b), the Si ₂ H ₆ supply step (S405c), and the purge step (S405d) are set as one cycle, and this cycle is executed a predetermined number of times (S405e). Thus, a second W layer having a predetermined thickness is formed on the heat-treated HfO ₂ film. Steps 405a to S405e are performed in the same manner as the first W layer forming step (S105a to S105e) described above. The thickness of the second W layer to be formed is, for example, not less than 0.5 nm and not more than 2 nm.

[Plasma O ₂ and / or NH ₃ Supply Step (S406)]
Subsequently, a plasma O ₂ and / or NH ₃ supply step (S406) is performed to modify the formed second W layer into a WO layer, a WN layer, or a WON layer. The plasma O ₂ and / or NH ₃ supply step (S406) is performed in the same manner as the plasma O ₂ and / or NH ₃ supply step (S306).

[Purge process (S407)]
Subsequently, a purge step (S407) is performed to remove O ₂ and / or NH ₃ gas and reaction byproducts remaining in the processing chamber 201, and the inside of the processing chamber 201 is purged with N ₂ gas. . The purge step (S407) is performed in the same manner as the residual gas removal step (S107).

[Third W Layer Formation Step (S408a to S408e)]
Subsequently, the WF ₆ supply step (S408a), the purge step (S408b), the Si ₂ H ₆ supply step (S408c), and the purge step (S408d) are set as one cycle, and this cycle is executed a predetermined number of times (S408e). Thus, a third W layer having a predetermined thickness is formed on the WO layer, the WN layer, or the WON layer in which the second W layer is modified to form an upper electrode. The upper electrode is formed by stacking a WO layer, WN film, or WON layer having a predetermined thickness and a third W layer having a predetermined thickness, and the bottom surface is changed to a WO layer, a WN layer, or a WON layer. It is configured as a quality W film. Steps 408a to S408e are performed in the same manner as the first W layer forming step (S105a to S105e) described above.

[Residual gas removing step (S409), substrate unloading step (S410)]
Then, after performing the same process as the above-mentioned residual gas removing process (S107) (S409), the procedure shown in the substrate loading process (S101) and the substrate placing process (S102) is reversed. The wafer 200 after the formation of the upper electrode is carried out from the processing chamber 201 into the negative pressure transfer chamber 11 (S410), and the substrate processing step according to this embodiment is completed.

  Also in this embodiment, there exists an effect similar to the above-mentioned embodiment. That is, it is possible to manufacture a semiconductor device including a metal film having a necessary work function and oxidation resistance at low cost. In addition, since the lower electrode formation process is simplified, the productivity of substrate processing can be improved.

<Still another embodiment of the present invention>
In the above-described embodiment, an example of forming a film using a single-wafer ALD apparatus that processes one substrate at a time as a substrate processing apparatus (film forming apparatus) has been described. It is not limited to. For example, the film may be formed using a batch type vertical ALD apparatus that processes a plurality of substrates at a time as a substrate processing apparatus. The vertical ALD apparatus will be described below.

  FIG. 10 is a schematic configuration diagram of a vertical processing furnace of a vertical ALD apparatus preferably used in this embodiment. FIG. 10A is a vertical sectional view of the processing furnace 302, and FIG. 10B is a processing furnace. 302 part is shown with the sectional view on the AA line of Fig.10 (a).

  As shown in FIG. 10A, 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 source gas supply pipe 213a is connected to the first nozzle 333a, and the oxygen-containing gas supply pipe 213b, the nitrogen-containing gas supply pipe 213g, and the silicon-containing gas supply pipe 213h are connected to the second nozzle 333b. This is different from the above-described embodiment. That is, in this embodiment, the source gas, the oxygen-containing gas, the nitrogen-containing gas, and the silicon-containing gas are supplied by separate nozzles. Further, oxygen-containing gas, nitrogen-containing gas, and silicon-containing 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 as 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, a gate valve 44, a negative pressure transfer device 11, a sub heater 206a, a valve. It controls operations of va1 to va5, vb1 to vb3, vc1 to vc3, ve1 to ve3, vg1 to vg3, vh1 to vh3, mass flow controllers 222a, 222b, 222c, 222e, 222g, 222h and the like.

  Next, an example in which the lower electrode or the upper electrode is formed on the wafer 200 as one step of the manufacturing process of the semiconductor device using the processing furnace 302 of the vertical ALD apparatus according to the above configuration will be described. In the following description, the operation of each part constituting the vertical ALD 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. 10A, the boat 317 holding a 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, a W film (lower electrode) whose surface is modified into a WO layer, a WN layer, or a WON layer on the wafer 200 by performing a formation process of the lower electrode or the upper electrode according to the above-described embodiment, Alternatively, a W film (upper electrode) whose bottom surface is modified into a WO layer, a WN layer, or a WON layer is formed.

Thereafter, the seal cap 319 is lowered by the boat elevator 315 to open the lower end of the manifold 309, and the lower end of the manifold 309 is held in the state where the wafer 200 after the lower electrode or the upper electrode is formed is held by the boat 317. From the process tube 303 to the outside (boat unloading). Thereafter, the processed wafer 200 is taken out from the boat 317 (wafer discharge).

  Also in this embodiment, there exists an effect similar to the above-mentioned embodiment. That is, it is possible to manufacture a semiconductor device including a metal film having a necessary work function and oxidation resistance at low cost.

<Still another embodiment of the present invention>
As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, It can change variously in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the case where the W film is formed as the metal film and the bottom surface or the surface of the W film is modified to the WO film, the WN film, or the WON film has been described. However, the present invention is limited to such a form. First, when a WN film is formed as a metal film and the bottom or surface of the WN film is modified to a WON film, a titanium nitride (TiN) film is formed as the metal film, and the bottom or surface of the TiN film is changed to a TiN film. The present invention can also be suitably applied when reforming.

In the above-described embodiment, the case where the HfO ₂ film is formed as the high dielectric constant insulating film has been described. However, the present invention is not limited to such a form, and examples of the high dielectric constant insulating film include an HfSiO film, an HfAlO film, and a ZrO film. _Two films, ZrSiO film, ZrAlO film, TiO ₂ film, Nb ₂ O ₅ film, Ta ₂ O ₅ film, SrTiO film, BaSrTiO film, PZT film are formed, or a film in which these are combined or mixed is formed The present invention can also be suitably applied to cases.

Further, in the embodiment described above, using O ₂ gas as an oxygen-containing gas (oxidizing source) has described the case of using NH ₃ gas as the nitrogen-containing gas (nitriding source), the present invention is not limited to the embodiment according. For example, may be used the O ₃ gas and the H _{2 O} gas in place of the O ₂ gas as an oxidizing source, it may be used N ₂ gas instead of NH ₃ gas as a nitriding source.

  In the above-described embodiment, the formation of the lower electrode and the upper electrode, the formation of the high dielectric constant insulating film, and the heat treatment are performed by separate processing containers, but the present invention is not limited to such a form. That is, the formation of the lower electrode, the upper electrode, and the high dielectric constant insulating film may be performed in the same processing container, and further, the formation of the high dielectric constant insulating film and the heat treatment are performed in the same processing container. It is good as well.

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

According to one aspect of the invention,
Carrying a substrate into a processing container;
Performing a process of forming a metal film having a predetermined thickness on the substrate by supplying and exhausting a processing gas into the processing container;
And a step of carrying out the processed substrate from the processing container,
In the step of performing the treatment, an oxygen-containing gas and / or a nitrogen-containing gas is activated with heat or plasma and supplied and exhausted in the treatment container during or after the formation of the metal film. A method of manufacturing a semiconductor device is provided in which the bottom surface or the surface of the metal film is modified to a conductive metal oxide layer, a conductive metal nitride layer, or a conductive metal oxynitride layer.

  Preferably, the conductive metal oxide layer, the conductive metal nitride layer, or the conductive metal oxynitride layer has a thickness of 0.5 nm to 2 nm.

Preferably, the oxygen concentration of the conductive metal oxide layer is 5% or more and 20% or less.
Preferably, the oxygen concentration of the conductive metal oxide layer is 5% or more and 10% or less.

Preferably, the conductive metal nitride layer has a nitrogen concentration of 5% to 20%.
Preferably, the nitrogen concentration of the conductive metal nitride layer is 5% or more and 10% or less.

Preferably, the total concentration of oxygen and nitrogen in the conductive metal oxynitride layer is 5% to 20%.
Preferably, the total concentration of oxygen and nitrogen in the conductive metal oxynitride layer is 5% to 10%.

Preferably, the metal film is a W film, and the conductive metal oxide layer is a WO layer.
Preferably, the metal film is a W film, and the conductive metal nitride layer is a WN layer.
Preferably, the metal film is a W film, and the conductive metal oxynitride layer is a WON layer.

Preferably, the metal film is a WN film, and the conductive metal oxynitride layer is a WON layer.
Preferably, the metal film is a TiN film, and the conductive metal oxynitride layer is a TiON layer.

According to another aspect of the invention,
A processing container for containing a substrate;
A processing gas supply system for supplying a processing gas into the processing container;
A reaction gas supply system for supplying an oxygen-containing gas and / or a nitrogen-containing gas activated by heat or plasma;
An exhaust system for exhausting the inside of the processing vessel;
A process gas is supplied to the process vessel containing the substrate and exhausted to perform a process of forming a metal film having a predetermined thickness on the substrate. At that time, the metal film is being formed or the metal After the film is formed, an oxygen-containing gas and / or a nitrogen-containing gas is activated with heat or plasma and supplied and exhausted into the processing container, so that the bottom surface or the surface of the metal film is electrically conductive metal oxide layer, conductive A control unit for controlling the processing gas supply system, the reaction gas supply system, and the exhaust system so as to be modified into a conductive metal nitride layer or a conductive metal oxynitride layer;
A substrate processing apparatus is provided.

200 wafer (substrate)
201 processing chamber 202 processing container 280 controller (control unit)

Claims (2)

Carrying a substrate into a processing container;
Performing a process of forming a metal film having a predetermined thickness on the substrate by supplying and exhausting a processing gas into the processing container;
And a step of carrying out the processed substrate from the processing container,
In the step of performing the treatment, an oxygen-containing gas and / or a nitrogen-containing gas is activated with heat or plasma and supplied and exhausted in the treatment container during or after the formation of the metal film. A method of manufacturing a semiconductor device, wherein the bottom surface or the surface of the metal film is modified into a conductive metal oxide layer, a conductive metal nitride layer, or a conductive metal oxynitride layer. A processing container for containing a substrate;
A processing gas supply system for supplying a processing gas into the processing container;
A reaction gas supply system for supplying an oxygen-containing gas and / or a nitrogen-containing gas activated by heat or plasma;
An exhaust system for exhausting the inside of the processing vessel;
A process gas is supplied to the process vessel containing the substrate and exhausted to perform a process of forming a metal film having a predetermined thickness on the substrate. At that time, the metal film is being formed or the metal After the film is formed, an oxygen-containing gas and / or a nitrogen-containing gas is activated with heat or plasma and supplied and exhausted into the processing container, so that the bottom surface or the surface of the metal film is electrically conductive metal oxide layer, conductive A control unit for controlling the processing gas supply system, the reaction gas supply system, and the exhaust system so as to be modified into a conductive metal nitride layer or a conductive metal oxynitride layer;
A substrate processing apparatus comprising:

Images