JPWO2018061965A1 - Semiconductor device manufacturing method, substrate processing apparatus, and program - Google Patents

Abstract

Problem: To provide a technique for making the thickness of a thin film in a plane of a substrate and the thickness of a thin film between a plurality of substrates uniform.
SOLUTION: A step of placing a plurality of substrates along a rotation direction of the substrate mounting table on a substrate mounting table rotatably provided in the processing chamber, and a step of providing in the processing chamber along the rotation direction of the substrate mounting table. Rotating the substrate mounting table so that the substrate passes through the first processing region and the second processing region, supplying a first element-containing gas containing the first element in the first processing region, Performing a plasma excitation of a mixed gas containing oxygen gas and hydrogen gas to generate active species and supplying the active species into the second processing region. The ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in the range of 95: 5 to 50:50.

Description

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

  For example, a substrate processing step of forming a thin film on a substrate may be performed as one step of a manufacturing process of a semiconductor device such as a flash memory or a DRAM. As a substrate processing apparatus for performing such a process, a substrate on which a thin film is formed on a substrate by moving a susceptor on which the substrate is placed and passing the substrate through a region where plasma of a processing gas is generated by a plasma generation unit A processing apparatus is known (see, for example, Patent Document 1).

JP 2011-222960 A

  In recent years, wiring dimensions and the like tend to be miniaturized, so it is important to make the thickness of the thin film in the plane of the substrate and the thickness of the thin film between a plurality of substrates uniform with good reproducibility. However, in the above-described substrate processing apparatus, the thickness of the thin film in the plane of the substrate and the thickness of the thin film between the plurality of substrates are made uniform with good reproducibility, particularly in the processing using the plasma generated by the plasma generation unit. There were cases where it was difficult to do.

  It is an object of the present invention to provide a method for manufacturing a semiconductor device, a substrate processing apparatus, and the like that make the thickness of a thin film in a plane of a substrate uniform and the thickness of a thin film between a plurality of substrates.

  According to one aspect of the present invention, a step of placing a plurality of substrates along a rotation direction of the substrate mounting table on a substrate mounting table rotatably provided in a processing chamber, and rotation of the substrate mounting table A step of rotating the substrate mounting table so that the substrate passes through a first processing region and a second processing region provided in the processing chamber along a direction; and a first element is contained in the first processing region Supplying a first element-containing gas, and generating a reactive species by plasma excitation of a mixed gas containing oxygen gas and hydrogen gas, and supplying the active species into the second processing region. Then, a method for manufacturing a semiconductor device is provided in which the ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in the range of 95: 5 to 50:50.

  According to the method for manufacturing a semiconductor device, the substrate processing apparatus, and the like according to the present invention, the thickness of the thin film in the plane of the substrate and the thickness of the thin film between the plurality of substrates can be made uniform.

The cross-sectional schematic of the process chamber with which the substrate processing apparatus which concerns on one Embodiment of this invention is provided. FIG. 2 is a schematic longitudinal sectional view of a process chamber included in the substrate processing apparatus according to the embodiment of the present invention, and is a cross-sectional view taken along line A-A ′ of the process chamber shown in FIG. 1 is a schematic top view of a process chamber provided in a substrate processing apparatus according to an embodiment of the present invention. The schematic block diagram of the controller of the substrate processing apparatus used suitably by one Embodiment of this invention. It is a flowchart which shows the substrate processing process which concerns on one Embodiment of this invention. It is a flowchart of the modification | reformation process which concerns on one Embodiment of this invention. The graph which shows the in-plane film thickness uniformity and WER ratio of the thin film formed in the 1st Example of this invention. The graph which shows the in-plane film thickness uniformity of the thin film formed in the comparative example 2 which concerns on this invention.

<First Embodiment of the Present Invention>
(1) Configuration of Substrate Processing Apparatus The substrate processing apparatus according to the first embodiment of the present invention includes a process chamber 202 as a processing furnace.

(Processing room)
As shown in FIGS. 1 and 2, the process chamber 202 includes a reaction vessel 203 which is a cylindrical airtight vessel. In the reaction vessel 203, a processing chamber 201 for processing the wafer 200 is formed.

  On the upper side in the reaction vessel 203, there are provided four partition plates 205 as divided structures extending radially from the center. The four partition plates 205 are provided so as to block the space from the ceiling in the processing chamber 201 to the position directly above the susceptor (substrate mounting table) 217. Accordingly, the four partition plates 205 are configured to partition the processing chamber 201 into a first processing region 201a, a first purge region 204a, a second processing region 201b, and a second purge region 204b. The first processing region 201a, the first purge region 204a, the second processing region 201b, and the second purge region 204b are arranged in this order along the rotation direction R of the susceptor 217.

  The lower end of the partition plate 205 is disposed as close to the susceptor 217 as the partition plate 205 does not interfere with the wafer 200. Thereby, there is little gas passing between the partition plate 205 and the susceptor 217. Therefore, mixing of different gases in each region is suppressed.

(Susceptor)
A susceptor 217 serving as a substrate mounting table is provided below the partition plate 205, that is, at the bottom center in the reaction vessel 203. Yes. The susceptor 217 is formed of a non-metallic material such as aluminum nitride (AlN), ceramics, or quartz so that the metal contamination of the wafer 200 can be reduced.

  The susceptor 217 is configured to support a plurality of (for example, five) wafers 200 side by side on the same surface and on the same circumference in the reaction vessel 203. Here, “on the same surface” is not limited to the completely same surface, and it is only necessary that the plurality of wafers 200 are arranged so as not to overlap each other when the susceptor 217 is viewed from above. The susceptor 217 is configured to arrange a plurality of wafers 200 side by side along the rotation direction.

  A wafer mounting portion 217 b is provided at the support position of the wafer 200 on the surface of the susceptor 217. The same number of wafer mounting portions 217b as the number of wafers 200 to be processed are arranged at equidistant positions (for example, at an interval of 72 °) at positions concentrically from the center of the susceptor 217. Each wafer mounting portion 217b has, for example, a circular shape when viewed from the top surface of the susceptor 217 and a concave shape when viewed from the side surface.

  The susceptor 217 is provided with a lifting mechanism 268 that lifts and lowers the susceptor 217. A plurality of through holes 217a are provided at the position of each wafer mounting portion 217b of the susceptor 217. A plurality of wafer push-up pins 266 that support the back surface of the wafer 200 when the wafer 200 is loaded into and unloaded from the reaction container 203 are provided on the bottom surface of the reaction container 203 described above. The through hole 217a and the wafer push-up pin 266 are arranged so that the wafer push-up pin 266 penetrates the through-hole 217a when the wafer push-up pin 266 is raised or when the susceptor 217 is lowered by the lifting mechanism 268. Has been.

  The elevating mechanism 268 is provided with a rotating mechanism 267 that rotates the susceptor 217. The rotation shaft of the rotation mechanism 267 is connected to the susceptor 217, and the susceptor 217 can be rotated by operating the rotation mechanism 267.

  A controller 300 is connected to the rotation mechanism 267 via a coupling unit 267a. By rotating the susceptor 217, the wafer 200 placed on the susceptor 217 passes through the first processing region 201a, the first purge region 204a, the second processing region 201b, and the second purge region 204b in this order. It becomes.

(Heating part)
A heater 218 as a heating unit is integrally embedded in the susceptor 217 so that the wafer 200 can be heated. When electric power is supplied to the heater 218, the surface of the wafer 200 can be heated to a predetermined temperature.

  The susceptor 217 is provided with a temperature sensor 274. A power regulator 224, a heater power source 225, and a temperature regulator 223 are electrically connected to the heater 218 and the temperature sensor 274 via a power supply line 222. Based on the temperature information detected by the temperature sensor 274, the power supply to the heater 218 is controlled.

Next, the gas supply system of the process chamber 202 will be described with reference to FIGS.

(First element-containing gas supply system)
A first gas inlet 281 is provided on the ceiling of the reaction vessel 203 in the first processing region 201a. The downstream end of the first gas supply pipe 231a is connected to the first gas inlet 281a provided at the upper end of the first gas inlet 281. The first gas introduction part 281 is configured to eject the first element-containing gas supplied from the first gas supply pipe 231a from the first gas outlet 283 opening in a slit shape to the first processing region 201a. Yes. The first gas supply pipe 231a is provided with a first element-containing gas supply source 231b, a mass flow controller (MFC) 231c, and a valve 231d that is an on-off valve.

  A downstream end of an inert gas supply pipe 234a that supplies an inert gas is connected to the downstream side of the valve 231d of the first gas supply pipe 231a. The inert gas supply pipe 234a is provided with an inert gas supply source 234b, an MFC 234c, and a valve 234d. The inert gas supplied into the first processing region 201a acts as a carrier gas or dilution gas for the first element-containing gas.

  The first element-containing gas supply system (the first gas supply system or the first element-containing gas) is mainly formed by the first gas supply pipe 231a, the MFC 231c, the valve 231d, the first gas introduction part 281 and the first gas outlet 283. Supply section). Note that the first element-containing gas supply source 231b may be included in the first element-containing gas supply system. Further, the inert gas supply pipe 234a, the MFC 234c, and the valve 234d may be included in the first element-containing gas supply system.

The first element-containing gas is a raw material gas (precursor), that is, one of the processing gases. Here, the first element is a metal element such as aluminum (Al) or titanium (Ti). For example, as the gas containing Al, a gas containing trimethylarnium (Al (CH ₃ ) ₃ : TMA) that is an organometallic compound can be used. Further, when the first element is silicon (Si), for example, a bistari butylaminosilane (BTBAS) gas can be used as the silicon-containing gas.

(Inert gas supply system)
An inert gas introduction part 282 is provided in the central part of the ceiling part of the reaction vessel 203. The side walls of the inert gas introduction part 282 on the first purge region 207a side and the second purge region 207b side are respectively opened to a first inert gas outlet 256 opening to the first purge region 207a and to a second purge region 207b. A second inert gas outlet 257 is provided.

  The downstream end of the second gas supply pipe 232a is connected to the upper end of the inert gas introduction part 282. The second gas supply pipe 232a is provided with an inert gas supply source 232b, an MFC 232c, and a valve 232d. The inert gas supplied into the first purge region 207a and the second purge region 207b acts as a purge gas.

Here, as the “inert gas”, for example, at least one of rare gases such as helium gas, neon gas, and argon gas, and nitrogen (N ₂ ) gas can be used. Here, N ₂ gas is used as the inert gas.

(Oxygen-containing gas supply system)
A communication port 203a is provided at the ceiling of the reaction vessel 203 and above the second processing region 201b. A plasma generation chamber 290 described later is connected to the communication port 203a (the opening of the plasma generation chamber 290 may be regarded as the communication port 203a). Further, an oxygen-containing gas ejection hole 294 b and a buffer chamber 294 a provided in the ceiling 292 are provided in the upper part of the plasma generation chamber 290. An oxygen-containing gas introduction hole 292a is provided in the upper part of the buffer chamber 294a, and the oxygen-containing gas is supplied into the plasma generation chamber 290 via the buffer chamber 294a and the oxygen-containing gas ejection hole 294b.

  The downstream end of the third gas supply pipe 233a is connected to the oxygen-containing gas introduction hole 292a. The third gas supply pipe 233a is provided with an oxygen gas supply source 233b, an MFC 233c, and a valve 233d that is an on-off valve. Further, the downstream end of the hydrogen gas supply pipe 235a is connected to the downstream side of the valve 233d of the third gas supply pipe 233a. The hydrogen gas supply pipe 235a is provided with a hydrogen gas supply source 235b, an MFC 235c, and a valve 235d.

The oxygen gas (O ₂ gas) supplied from the oxygen gas supply source 233b merges with the hydrogen gas (H ₂ gas) supplied from the hydrogen gas supply source 235b in the third gas supply pipe 233a. The combined O ₂ gas and H ₂ gas become a mixed gas containing oxygen and hydrogen (hereinafter, also simply referred to as a mixed gas), and through the third gas supply pipe 233a, the plasma generation chamber 290, and the communication port 203a, It is supplied into the second processing area 201b.

  The third gas supply pipe 233a, MFC 233c, and valve 233d constitute an oxygen gas supply system. The hydrogen gas supply pipe 235a, MFC 235c, and valve 235d constitute a hydrogen gas supply system. Further, the oxygen gas supply system and the oxygen gas supply system constitute an oxygen-containing gas supply system (oxygen-containing gas supply unit). Note that the oxygen gas supply source 233b and the hydrogen gas supply source 235b may be included in the oxygen-containing gas supply system.

  An inert gas supply system that supplies an inert gas as a dilution gas or a carrier gas may be added to the oxygen-containing gas supply system.

The oxygen-containing gas is one of the processing gases and may be considered as a reaction gas or a reformed gas. In this embodiment, O ₂ gas is used as the oxygen source, but ozone (O ₃ ) gas may be used instead.

(Exhaust system)
As shown in FIG. 2, an exhaust port 240 for exhausting the inside of the reaction vessel 203 is provided at the bottom of the reaction vessel 203. The upstream end of the exhaust pipe 241 is connected to each exhaust port 240. A vacuum pump 246 is connected to the downstream side of the merging portion of the exhaust pipe 241 through a pressure sensor 248, an APC (Auto Pressure Controller) valve 243, and a valve 245, and the pressure in the processing chamber 201 is predetermined. It is configured so that it can be evacuated so that the pressure of An exhaust system is mainly configured by the exhaust pipe 241, the APC valve 243, and the valve 245.

(Plasma generator)
As shown in FIGS. 2 and 3, a communication port having an opening longer than the substrate diameter of the wafer 200 in the radial direction of the reaction vessel 203 at the ceiling in the second processing region 201 b of the reaction vessel 203. 203a is provided. A plasma generation chamber 290 is connected to the upper part of the communication port 203a. The plasma generation chamber 290 has a side wall 291 and a ceiling 292.

  The communication port 203 a has an oval shape or an elliptical shape, and the direction of the long side (the direction of the long axis) is the radial direction of the reaction vessel 203. That is, the direction of the long side of the communication port 203a and the moving direction R of the wafer 200 passing directly below the communication port 203a are perpendicular to each other. The side wall 291 of the plasma generation chamber 290 has a cylindrical structure having the same cross-sectional shape as the communication port 203a, and a coil 293 is wound around the outer periphery. The side wall 291 is made of, for example, quartz. The communication port 203a is provided at a position facing the wafer 200 passing below, and is arranged at a position where the outer periphery of the wafer 200 passes through the inside of the communication port 203a.

  The coil 293 is connected with a waveform adjustment circuit 296, an RF sensor 297, a high frequency power supply 298, and a frequency matching unit 299. The coil 293 is surrounded by a shielding plate 295. The high frequency power source 298 supplies high frequency power to the coil 293. The RF sensor 297 monitors information on high-frequency traveling waves and reflected waves that are supplied. The frequency matching unit 299 controls the high-frequency power supply 298 so that the reflected wave is minimized based on the information on the reflected wave monitored by the RF sensor 297.

  Since the coil 293 forms a standing wave having a predetermined wavelength, the winding diameter, the winding pitch, and the number of turns are set so as to resonate in a constant wavelength mode. That is, the combined electrical length of the coil 293 and the adjacent waveform adjustment circuit 296 is a length corresponding to an integral multiple (1 times, 2 times,...) Of one wavelength at a predetermined frequency of the power supplied from the high frequency power supply 298. Is set.

  The plasma generation unit 270 according to this embodiment is mainly configured by the plasma generation chamber 290, the coil 293, the waveform adjustment circuit 296, the RF sensor 297, and the frequency matching unit 299. Note that the plasma generation unit 270 may include a high-frequency power source 298.

  In order to compensate for a resonance shift in the coil 293 when the plasma is generated, the frequency matching unit 299 has a function of detecting the reflected wave power from the coil 293 when the plasma is generated and complementing the output. With such a configuration, in the resonance device of the present invention, a standing wave can be more accurately formed in the coil 293, and plasma with extremely little capacitive coupling can be generated.

(Control part)
As shown in FIG. 4, a controller 300 as a control unit (control means) is configured as a computer including a CPU (Central Processing Unit) 301a, a RAM (Random Access Memory) 301b, a storage device 301c, and an I / O port 301d. Has been. The RAM 301b, the storage device 301c, and the I / O port 301d are configured to exchange data with the CPU 301a via the internal bus 301e. For example, an input / output device 302 configured as a touch panel or the like is connected to the controller 300.

  The storage device 301c includes, for example, a flash memory, an HDD (Hard Disk Drive), and the like. In the storage device 301c, a control program that controls the operation of the substrate processing apparatus, a process recipe that describes the procedure and conditions of the substrate processing described later, and the like are stored in a readable manner. The process recipe is a combination of instructions so that the controller 300 can execute each procedure in a substrate processing step to be described later to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, the control program, and the like are collectively referred to simply as a program. The process recipe is also simply called a recipe. When the term “program” is used in this specification, it may include only a recipe, only a control program, or both. The RAM 301b is configured as a memory area that temporarily stores programs, data, and the like read by the CPU 301a.

  The I / O port 301d includes an MFC 231c to 235c, a valve 231d to 235d, a pressure sensor 248, an APC valve 243, a vacuum pump 246, a temperature sensor 249, an RF sensor 297, a frequency matching unit 299, a high frequency power supply 298, a rotating mechanism 267, and a lift The mechanism 268, the heater 218, the power regulator 224, the heater power source 225, the temperature regulator 223, and the like are connected.

  The CPU 301a is configured to read and execute a control program from the storage device 301c, and to read a recipe from the storage device 301c in response to an operation command input from the input / output device 302 or the like. Based on the read recipe contents, the CPU 301a adjusts the flow rates of various gases by the MFCs 231c to 235c, the opening / closing operations of the valves 231d to 235d, the pressure adjusting operation by the APC valve 243 based on the pressure sensor 248, and the temperature sensor 274. Temperature adjustment operation of the heater 218, start and stop of the vacuum pump 246, rotation and rotation speed adjustment operation of the susceptor 217 by the rotating mechanism 267, lifting operation of the susceptor 217 by the lifting mechanism 268, power supply and stop by the high frequency power source 298, frequency matching The controller 299 is configured to control the impedance adjustment operation and the like.

  The controller 300 installs the above-mentioned program stored in an external storage device 303 (for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, a semiconductor memory such as a USB memory) 303 in a computer. Can be configured. The storage device 301c and the external storage device 303 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as a recording medium. When the term “recording medium” is used in this specification, it may include only the storage device 121c alone, may include only the external storage device 303 alone, or may include both of them. The program may be provided to the computer using a communication unit such as the Internet or a dedicated line without using the external storage device 303.

(3) Substrate Processing Step Next, a substrate processing step using a substrate processing apparatus including the process chamber 202 will be described as one step of the semiconductor manufacturing process according to the present embodiment.

  First, the outline of the substrate processing step will be described with reference to FIGS. In the following description, the operation of each component of the process chamber 202 is controlled by the controller 300.

Here, a TMA-containing gas that is an Al-containing gas (hereinafter simply referred to as TMA gas) is used as the first element-containing gas, and a mixed gas of O ₂ gas and H ₂ gas (hereinafter simply referred to as a mixed gas) is used as the oxygen-containing gas. An example of forming a film of aluminum oxide (Al ₂ O ₃ ) as a thin film on the wafer 200 will be described.

(Substrate loading / placement step S102)
First, the susceptor 217 is lowered to the transfer position of the wafer 200, so that the wafer push-up pins 266 protrude from the surface of the susceptor 217. Subsequently, a predetermined number (five) of wafers 200 (processing substrates) are respectively mounted on the wafer push-up pins 266 in a horizontal posture by using a wafer transfer machine. Subsequently, by raising the susceptor 217, the wafer 200 is mounted on each mounting portion 217b. Further, the gate valve 151 is closed to seal the inside of the reaction vessel 203, and the vacuum pump 246 is always operated at least from the substrate loading / mounting step (S102) to the substrate unloading step (S106) described later. State.

  When the wafer 200 is placed on the susceptor 217, electric power is supplied to the heater 218 so that the surface of the wafer 200 is controlled to a predetermined temperature. In the present embodiment, the temperature of the wafer 200 is, for example, a predetermined temperature in a range of room temperature to less than 300 ° C., preferably a predetermined temperature in a range of 100 ° C. to less than 300 ° C., more preferably 100 ° C. The predetermined temperature is in the range of 200 ° C. or higher. If the temperature of the wafer 200 is lower than room temperature, there is a possibility that the TMA gas is not sufficiently adsorbed on the wafer 200. There is a possibility that.

  In the heat treatment of the wafer 200 made of silicon, if the surface temperature is heated to 750 ° C. or higher, impurity diffusion occurs in the source region and drain region formed on the surface of the wafer 200, and the circuit characteristics deteriorate. However, the performance of the semiconductor device may be degraded. By limiting the temperature of the wafer 200 as described above, it is possible to suppress the diffusion of impurities in the source and drain regions formed on the surface of the wafer 200, the deterioration of circuit characteristics, and the deterioration of the performance of semiconductor devices.

  Further, when a thin film is formed on the photoresist pattern in a state where the photoresist pattern is formed on the wafer 200 as in the double patterning method, the temperature of the wafer 200 is, for example, a high temperature exceeding 200 ° C. There is a possibility that the photoresist pattern is thermally changed. In this embodiment, since the substrate processing process can be performed at a low temperature, the deterioration of the photoresist film can be suppressed.

(Thin film forming step S104)
In the thin film forming step S104, a TMA gas that is a first element-containing gas is supplied into the first processing region 201a, a mixed gas that is an oxygen-containing gas is supplied into the second processing region 201b, and Al ₂ is applied onto the wafer 200. An O ₃ film is formed.

In the thin film forming step S104, N ₂ gas as a purge gas is continuously supplied from the inert gas supply system into the first purge region 204a and the second purge region 204b after the substrate carry-in / placement step S102. Yes.

(Susceptor rotation start S202)
When the wafer 200 is placed on each wafer placement unit 217b, the rotation mechanism 267 starts to rotate the susceptor 217. The rotational speed of the susceptor 217 is, for example, not less than 1 revolution / minute and not more than 100 revolutions / minute.

(Gas supply start S204)
When the wafer 200 reaches a desired temperature and the susceptor 217 reaches a desired rotation speed, supply of TMA gas together with an inert gas into the first processing region 201a is started, and further mixed into the second processing region 201b. Supply gas.

The supply flow rate of the TMA gas is, for example, 10 sccm or more and 50 sccm or less, and more preferably, for example, about 20 sccm. Further, the supply flow rate of N ₂ gas as the inert gas supplied at the same time is a predetermined value in the range of, for example, 100 sccm or more and 500 sccm or less, more preferably about 225 sccm, for example. In the present embodiment, TMA gas is kept flowing at a constant flow rate until a third step S210 described later.

The mixed gas introduced into the buffer chamber 294a is supplied to the plasma generation chamber 290 via the oxygen-containing gas ejection hole 294b. The mixed gas supplied through the oxygen-containing gas ejection hole 294 b is diffused in the direction of the side wall 291 and supplied to the vicinity of the coil 293 along the side wall 291. The supply flow rate of the mixed gas is, for example, a predetermined value in a range of 1000 sccm to 4000 sccm, and more preferably about 3000 sccm. Here, in this embodiment, as will be described later, the MFCs 233c and 235d are controlled so that the flow rate ratio (or volume ratio) of the O ₂ gas and the H ₂ gas in the mixed gas becomes a predetermined ratio. In the present embodiment, the mixed gas continues to flow at a constant flow rate until the plasma generation stop S210.

  In this embodiment, by controlling the APC valve 243, the pressure in the processing chamber 201 is set to a predetermined value in the range of 1 Pa to 10 kPa, for example, preferably in the range of 100 Pa to 200 Pa, more preferably About 120 Pa.

  Note that an Al-containing layer having a predetermined thickness, which will be described later, starts to be formed on the surface of the wafer 200 from the start of gas supply S204. Further, in order to stabilize the flow rate of the mixed gas before plasma generation in the plasma generation chamber 290, the TMA gas is adsorbed on the surface of the wafer 200 and forms an Al-containing layer at the latest until the wafer 200 makes one turn. In the meantime, it is desirable to start supplying the mixed gas.

(Plasma generation start S206)
Next, by starting the supply of high-frequency power to the coil 293 of the plasma generation unit 270, the mixed gas is excited in a plasma state in the plasma generation chamber 290 that is the upper space of the second processing region 201b.

  Specifically, when the flow rates of TMA gas and oxygen gas and the pressure in the processing chamber 201 are stabilized, application of high frequency power to the coil 293 is started by the high frequency power source 298. As a result, the induction plasma is excited along the side wall 291 in the plasma generation chamber 290. The plasma mixed gas is dissociated, and reactive species such as active species including oxygen atoms and hydrogen atoms, active species including only oxygen atoms, active species including only hydrogen atoms, and so on (hereinafter collectively referred to as active species). Etc.) is generated. Active species and the like generated in the plasma generation chamber 290 are supplied into the second processing region 201b via the communication port 203a.

(Modification step S208)
Thereafter, plasma generation by the plasma generation unit 270 is continued, and a modification step S208 is performed in which an Al ₂ O ₃ layer is formed on the wafer 200. In the modification step S208, the susceptor 217 is continuously rotated so that the wafer 200 passes through the first processing region 201a, the first purge region 204a, the second processing region 201b, and the second purge region 204b in this order. As a result, the TMA gas supply, the inert gas supply, the plasma mixed gas supply, and the inert gas supply are performed on the wafer 200 as one cycle, and this cycle is sequentially performed.

  Hereinafter, the details of the reforming step S208 will be described with reference to FIG.

(First processing area passage S302)
TMA gas is supplied to the wafer 200 when the wafer 200 passes through the first processing region 201a. An Al-containing layer as a “first element-containing layer” is formed on the surface of the wafer 200 by contacting the TMA gas on the wafer 200.

(First purge region passage S304)
Next, the wafer 200 moves to the first purge region 204a. When the wafer 200 passes through the first purge region 204a, the TMA gas component that could not be bonded to the wafer 200 in the first processing region 201a is removed from the wafer 200 by the inert gas.

(Second processing area passage S306)
Next, the wafer 200 moves to the second processing area 201b. Here, the wafer 200 moves under the plasma generation chamber 290 while moving in the rotation direction R so as to be orthogonal to the long side direction of the horizontal cross section (the same shape as the communication port 203a) of the oval or elliptical side wall 291. pass.

In the plasma generation chamber 290, induction plasma is formed along the side wall 291 as described above, and oxygen atoms generated by plasma excitation in the plasma generation chamber 290 when the wafer 200 passes below the plasma generation chamber 290. In addition, the Al-containing layer is modified into an Al ₂ O ₃ layer by active species including at least one of hydrogen atoms.

(Second purge region passage S308)
Next, the wafer 200 moves to the second purge region 204b. When the wafer 200 passes through the second purge region 204b, the component of the mixed gas that could not be bonded to the wafer 200 in the second processing region 201b is removed from the wafer 200 by the inert gas.

(Decision S310)
During this time, the controller 300 determines whether or not the one cycle has been performed a predetermined number of times. Specifically, the controller 300 counts the rotation speed of the susceptor 217. When the predetermined number of times has not been performed (No in S310), the rotation of the susceptor 217 is further continued, and the cycles of S302, S304, S306, and S308 are repeated. When it has been carried out a predetermined number of times (Yes in S310), the reforming step S208 is terminated.

(Plasma production stop S210)
Next, after the reforming step 208, power supply to the plasma generation unit 270 is stopped, and plasma generation is stopped.

(Gas supply stop S212)
After the plasma generation stop S210, at least the valve 232d and the valve 233d are closed, and the supply of the first element-containing gas and the mixed gas to the first processing region 201a and the second processing region 201b is stopped.

(Susceptor rotation stop S214)
After the gas supply stop S212, the rotation of the susceptor 217 is stopped. Thus, the thin film forming step S104 is completed.

(Substrate unloading step S106)
Next, the susceptor 217 is lowered and the wafer 200 is supported on the wafer push-up pins 266 protruding from the surface of the susceptor 217. Thereafter, the gate valve 151 is opened, and the wafer 200 is carried out of the reaction vessel 203 using a wafer transfer machine. Thus, the substrate processing process is completed.

(4) Details of Modification Step S208 Here, the following problems exist in forming the Al ₂ O ₃ layer in the modification step S208.

In the present embodiment, the process chamber 202 is configured such that the wafer 200 moves by circling the center of the reaction vessel 203 and passes through each processing region. Accordingly, the moving speed of the wafer 200 relative to the rotational angular velocity of the susceptor 217 is smaller in the surface region closer to the center of the reaction vessel 203, and conversely, the moving speed of the wafer 200 relative to the rotational angular velocity of the susceptor 217 is smaller in the surface region closer to the outer peripheral side of the reaction vessel 203. Becomes larger. Therefore, the time per cycle that passes under the communication port 203a and is exposed to the active species and the like is longer in the surface area of the wafer 200 closer to the center of the reaction vessel 203, and conversely, The surface area closer to the outer peripheral side is shorter. As a result, the reforming reaction is not sufficiently performed in the surface region where the processing time per cycle is shortened, and the film thickness of the formed Al ₂ O ₃ film becomes non-uniform in the surface. Moreover, the film quality of the Al ₂ O ₃ film formed in the surface region where the reforming reaction is not sufficiently performed becomes low. Such a problem becomes more prominent when the rotational speed of the susceptor 217 is increased.

In order to solve the above-mentioned problems, the inventors have promoted the reforming reaction by increasing the high-frequency power supplied to the coil 293 when the oxygen-containing gas is plasma-excited to increase the density of active species, etc. We considered making it. However, this method could not obtain a significant improvement result. Therefore, as a further solution, the inventor used a mixed gas of O ₂ gas and H ₂ gas as a processing gas to be plasma-excited in the step of modifying the Al-containing layer as in this embodiment. Hereinafter, a comparison between the comparative example and this embodiment will be shown.

<Comparative Example 1>
In Comparative Example 1, the process of forming the Al ₂ O ₃ film was performed under the following processing conditions using the process chamber 202 in the present embodiment. The processing procedure is the same as that of this embodiment described above. Under the following processing conditions, only O ₂ gas is used as the plasma-excited oxygen-containing gas, and H ₂ gas is not mixed.
・ High frequency power: 500W
Supply flow rate 1 (TMA gas / N ₂ gas): 20 sccm / 225 sccm
・ Supply flow rate 2 (O ₂ gas / H ₂ gas): 3000 sccm / no supply ・ Processing chamber pressure: 120 Pa
-Substrate temperature: 200 ° C
-Susceptor rotation speed: 60 rpm
・ Processing time: 25 min

<First embodiment>
On the other hand, as a first example of this embodiment, an Al ₂ O ₃ film forming process was performed under the following processing conditions. The only difference in the processing conditions between the first example and the comparative example 1 is the presence or absence of mixing of H ₂ gas in the oxygen-containing gas.
Supply flow rate 1 (TMA gas / N ₂ gas): 20 sccm / 225 sccm
Supply flow rate 2 (O ₂ gas / H ₂ gas): 2750 sccm / 250 sccm

Next, analysis data relating to the film thicknesses of the thin films formed in Comparative Example 1 and the first example are shown below.
a) Comparative Example 1
-In-plane film thickness uniformity [±%]: 2.30%
・ In-plane film thickness uniformity [ρ%]: 1.46%
・ In-plane maximum film thickness difference: 85.19 mm
Film formation rate [Å / cycle]: 1.23
b) First Example In-plane film thickness uniformity [±%]: 0.76%
-In-plane film thickness uniformity [ρ%]: 0.55%
・ In-plane maximum film thickness difference: 29.95 mm
Film formation rate [Å / cycle]: 1.32

From the comparison of the experimental results, it can be seen that the in-plane film thickness uniformity of the wafer was greatly improved by mixing H ₂ gas with the oxygen-containing gas in the first example. It can also be seen that the film formation rate was improved in the first example as compared with Comparative Example 1.

Here, regarding the improvement of the in-plane film thickness uniformity in the first embodiment, by using a mixed gas of O ₂ gas and H ₂ gas as the oxygen-containing gas to be plasma-excited, in the second processing region passage S306 It is presumed that this is because the reforming reaction on the Al-containing layer was promoted. That is, it is considered that the oxidizing power for the Al-containing layer was improved by using this mixed gas. Furthermore, since the reforming reaction of the Al-containing layer is sufficiently performed even on the surface region on the wafer 200 with a short time to be exposed to the active species and the like generated by plasma excitation, the time to be exposed to the active species and the like. Regardless of the length, it is considered that the Al-containing layer can be uniformly modified in one cycle.

Furthermore, in the first embodiment, the reforming reaction for the Al-containing layer is sufficiently performed over the entire surface of the wafer 200, so that the deposition rate of the Al ₂ O ₃ film can be improved. Similarly, in the first embodiment, the reforming reaction is sufficiently performed on the Al-containing layer even in the surface region of the wafer 200 with a short processing time, and thus Al ₂ O ₃ formed is also formed in those surface regions. The film quality of the film, for example, the wet etching rate (WER) can be improved. As a factor for improving WER, it is also conceivable that impurities in the formed Al ₂ O ₃ film are reduced and removed by the action of activated hydrogen atoms contained in the mixed gas.

  In this embodiment, active species including hydrogen atoms are supplied to the wafer 200. However, active species including hydrogen atoms, such as OH radicals, are particularly easily deactivated compared to other active species. . Therefore, it is particularly preferable that the active species or the like be directly supplied from the plasma generation chamber 290 in which plasma is generated to the wafer 200 in the processing chamber 201 as in the plasma generation unit in the present embodiment.

<Second embodiment>
Subsequently, as a second embodiment, the flow rate ratio of O ₂ gas and H ₂ gas in the oxygen-containing gas is changed, the in-plane film thickness uniformity of the wafer 200 at each flow rate ratio, and the formed Al ₂ O _3. WER indicating the film quality of the film was measured. FIG. 7 shows the measurement results. The processing conditions are the same as in the first embodiment except for the flow rate ratio of O ₂ gas and H ₂ gas.

The horizontal axis of the graph shown in FIG. 7 indicates the concentration of H ₂ gas in the mixed gas of O ₂ gas and H ₂ gas (the flow rate ratio of H ₂ gas in the mixed gas). In the graph, ■ indicates the measured value of the in-plane film thickness uniformity of the wafer 200, and ◆ indicates the measured value of WER of the formed Al ₂ O ₃ film.

From the measurement result in this example, the concentration of H ₂ gas is 0% (the flow rate ratio of O ₂ gas and H ₂ gas is 100: 0), that is, the in-plane film thickness uniformity is 2. Although it was about 5%, when the concentration of H ₂ gas is 5% (the flow rate ratio is 95: 5), it can be seen that the in-plane film thickness uniformity is greatly improved to less than 1%. It can also be seen that the in-plane film thickness uniformity can be maintained at less than 1% when the concentration of H ₂ gas is in the range of 5% or more and 50% or less (the same flow ratio is 50:50). In addition, in the range where the concentration of H ₂ gas exceeds 50%, the reforming reaction is reduced due to the decrease in the concentration of O ₂ gas, so that it is estimated that the in-plane film thickness uniformity is deteriorated. Therefore, in order to improve the in-plane film thickness uniformity, it is desirable to set the concentration of H ₂ gas to a predetermined concentration in the range of 5% to 50%.

On the other hand, the same improvement can be confirmed for WER. If the WER ratio with WER of 1 when the concentration of H ₂ gas is 0% is used as an index, the WER ratio is 0.7 when the concentration of H ₂ gas is 10% (the flow rate ratio is 90:10). It can be seen that the level has been improved. It can also be seen that the WER ratio can be maintained at the same level when the concentration of H ₂ gas is 10% or more. In addition, in the range where the concentration of H ₂ gas exceeds 80%, it is estimated that the WER ratio is deteriorated because the reforming reaction is not sufficiently performed due to the decrease in the concentration of O ₂ gas. Therefore, in order to improve WER, it is desirable to set the concentration of H ₂ gas to a predetermined concentration in the range of 10% or more.

In order to improve both in-plane film thickness uniformity and WER, it is desirable to set the concentration of H ₂ gas to a predetermined concentration in the range of 10% to 50%.

Note that the oxygen-containing gas is not limited to a mixed gas of O ₂ gas and H ₂ gas, and a single gas containing oxygen atoms and hydrogen atoms such as water vapor (H ₂ O) may be used. However, when a single gas is used, the ratio of oxygen atoms to hydrogen atoms in the oxygen-containing gas cannot be arbitrarily selected, and it is difficult to achieve a desired ratio. For example, when only H ₂ O is used, the ratio of oxygen atoms to hydrogen atoms in the gas cannot be set to a desirable ratio such as 50:50 to 95: 5. On the other hand, in this embodiment including the first example and the second example, a mixed gas of O ₂ gas and H ₂ gas whose flow rate can be individually adjusted by the MFCs 233c and 235c is used as the oxygen-containing gas. ing. Therefore, the ratio of oxygen atoms to hydrogen atoms in the mixed gas can be easily adjusted by adjusting the flow rate of each gas.

<Comparative Example 2>
Subsequently, in the present embodiment, an example in which TMA gas is used as the first element-containing gas while titanium tetrachloride (TiCl ₄ ) gas is used as the second element-containing gas will be described as Comparative Example 2. In Comparative Example 2, a titanium oxide (TiO) film is formed on the wafer 200 by using TiCl ₄ gas.

The processing conditions in Comparative Example 2 are substantially the same as in the second example except that the type and flow rate of the first element-containing gas are as follows.
Supply flow rate 1 (TiCl ₄ gas / N ₂ gas): 60 sccm / 350 sccm

Similarly to the second example, the flow rate ratio of O ₂ gas and H ₂ gas in the oxygen-containing gas was changed, and the in-plane film thickness uniformity of the wafer 200 at each flow rate ratio was measured. FIG. 8 shows the measurement results.

In the measurement result in Comparative Example 2, the in-plane film thickness uniformity was about 2.6% when the H ₂ gas concentration was 0%. On the other hand, when H ₂ gas is mixed, in-plane film thickness uniformity is greatly improved in the present embodiment using TMA gas, but in Comparative Example 2, it is a case where H ₂ gas is mixed. However, no significant improvement in in-plane film thickness uniformity was confirmed.

Such a difference in effect between the present embodiment and Comparative Example 2 occurs because there is a difference in the likelihood of reaction between the first element-containing gas and the active species containing hydrogen atoms. Presumed to be. For example, an active species generated by plasma excitation of a mixed gas of O ₂ gas and H ₂ gas is more likely to cause a reforming reaction with an organic metal material such as TMA than an inorganic metal material such as TiCl _4. Conceivable. In particular, a metal raw material having an alkyl group such as a methyl group or an ethyl group as a ligand is particularly suitable in the present embodiment because it is likely to cause a modification reaction in which the alkyl group is eliminated and oxidized. .

<Other Embodiments 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.

The ligand contained in the first element-containing gas may be, for example, an alkyl group such as an ethyl group or a butyl group, a cyclopentadienyl group, a carbonyl group, or the like. Examples of the first element-containing gas include Ti [(C ₂ H ₅ ) ₂ N] ₄ , Ti [N (CH ₃ ) ₂ ] ₄ , Ta (OC ₂ H ₅ ) ₅ , Hf [N (CH _{3) CH 2 CH 3] 4} , Hf [N (CH 3) 2] 4, Hf [N (C 2 H 5) 2] 4, Zr [N (CH 3) CH 2 CH 3] 4, Zr [N (CH ₃ ) ₂ ] ₄ , Zr [N (C ₂ H ₅ ) ₂ ] ₄ , (C ₅ H ₅ ) Zr [N (CH ₃ ) ₂ ] ₃ , (C ₄ H ₉ NH) ₂ W (C ₄ Organometallic raw materials such as H ₉ N) ₂ , W (CO) ₆ , C ₁₄ H ₁₈ Co, CoCO) ₆ , Y (C ₅ H ₄ CH ₂ (CH ₂ ) ₂ CH ₃ ) ₃ , C ₁₄ H ₁₈ Ru It is also possible to use gas.

200 wafer (substrate)
201a 1st processing area 201b 2nd processing area 203 Reaction container 206 Plasma generation part 217 Susceptor

Claims (10)

Placing a plurality of substrates along a rotation direction of the substrate mounting table on a substrate mounting table rotatably provided in the processing chamber;
Rotating the substrate mounting table so that the substrate passes through a first processing region and a second processing region provided in the processing chamber along a rotation direction of the substrate mounting table;
Supplying a first element-containing gas containing a first element in the first processing region;
Plasma-excited mixed gas containing oxygen gas and hydrogen gas to generate active species, and supplying the active species into the second processing region,
The ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in the range of 95: 5 to 50:50.
A method for manufacturing a semiconductor device.   The method according to claim 1, wherein a ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in a range of 90:10 to 50:50.   The method according to claim 1, further comprising a step of heating the substrate to a predetermined temperature in a range of 100 ° C. or more and less than 300 ° C. after the step of placing the substrate on the substrate mounting table. The method according to claim 3, wherein in the step of heating the substrate to a predetermined temperature, the substrate is heated to a predetermined temperature in a range of 100 ° C. or higher and 200 ° C. or lower.   The method according to claim 1, wherein the first element-containing gas is a gas containing an organometallic compound having a methyl group.   The method according to claim 5, wherein the organometallic compound is trimethylaluminum. In the step of supplying the active species into the second processing region, the active species are supplied into the second processing region via an active species supply port provided in the second processing region.
The method of claim 1. The mixed gas is excited by a plasma generator,
The plasma generation unit is provided around the plasma generation chamber to which the mixed gas is supplied and the plasma generation chamber, and receives the application of high frequency power to plasma-excite the mixed gas supplied into the plasma generation chamber A coil, and
The active species supply port is provided in an upper part of the second processing region so as to face the substrate passing through the second processing region.
The method of claim 7. A processing chamber for processing the substrate;
A substrate mounting table provided with a substrate mounting surface that is rotatably provided in the processing chamber and on which a plurality of substrates are mounted along the rotation direction;
A heating unit configured to heat the substrate placed on the substrate placement surface;
A rotation mechanism for rotating the substrate mounting table;
A first processing region and a second processing region, which are provided in the processing chamber along the rotation direction of the substrate mounting table and process the plurality of substrates;
A first element-containing gas supply unit for supplying a first element-containing gas containing a first element to the first processing region;
A plasma generating unit for generating active species by plasma-exciting a mixed gas containing oxygen gas and hydrogen gas;
A mixed gas supply unit for supplying the mixed gas to the plasma generation unit;
An active species supply port provided in the second processing region and configured to supply the active species generated by the plasma generation unit into the second processing region;
Control configured to control the heating unit so as to control the mixed gas supply unit so that a ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in a range of 95: 5 to 50:50. And
A substrate processing apparatus comprising: A procedure for mounting a plurality of substrates along a rotation direction of the substrate mounting table on a substrate mounting table rotatably provided in a processing chamber of the substrate processing apparatus;
Rotating the substrate mounting table so that the substrate passes through a first processing region and a second processing region provided in the processing chamber along a rotation direction of the substrate mounting table;
Supplying a first element-containing gas containing a first element in the first processing region;
A step of plasma-exciting a mixed gas containing oxygen gas and hydrogen gas to generate active species, and supplying the active species into the second processing region,
The ratio of oxygen gas to hydrogen gas in the mixed gas is a predetermined ratio in the range of 95: 5 to 50:50.
A program to be executed by the substrate processing apparatus by a computer.