Substrate treatment method and substrate treatment apparatus

Abstract

To improve coverage of a TiSiN film.SOLUTION: A substrate treatment method of forming a TiSiN film in which a titanium nitride film and a silicon nitride film are laminated on a surface of a substrate includes: (a) preparing the substrate on a stage in a treatment container; (b) supplying Ti material gas containing Ti material and nitriding gas alternately into the treatment container X times to form the titanium nitride film; and (c) supplying Si material gas containing Si material and nitriding gas into the treatment container and supplying the Si material gas at least Y times to form the silicon nitride film, where (d) the (b) and the (c) are executed in this order Z times; the X and the Z are integers of 1 or more; and the Y is an integer of 2 or more.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] Patent Document 1 proposes a first film forming step including a first step of supplying a first source gas containing a metal into a processing chamber and removing the first source gas from the processing chamber, a second step of supplying a second source gas for reducing the first source gas into the processing chamber and removing the second source gas from the processing chamber, and a third step of supplying a third source gas containing silicon into the processing chamber and removing the third source gas from the processing chamber, and further has a second film forming step of forming a conductive layer on a layer containing metal, nitrogen, and silicon formed by the first film forming step.

[0003] Patent Document 2 proposes a film forming method including a step of providing a substrate in a processing chamber, a step of forming a metal-based film on the substrate in the processing chamber, and then a step of supplying a Si-containing gas into the processing chamber with the substrate provided therein.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a substrate processing method and a substrate processing apparatus capable of improving the coverage of a TiSiN film.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, there is provided a substrate processing method for forming a TiSiN film in which a titanium nitride film and a silicon nitride film are laminated on the surface of a substrate, including: (a) preparing the substrate on a stage in a processing chamber; (b) alternately supplying an X number of times a Ti source gas containing a Ti source and a nitriding gas into the processing chamber to form the titanium nitride film; (c) supplying a Si source gas containing a Si source and a nitriding gas into the processing chamber, wherein the Si source gas is supplied at least Y number of times to form the silicon nitride film; (d) performing the steps (b) and (c) in this order Z number of times, where X and Z are integers of 1 or more, and Y is an integer of 2 or more.

Advantages of the Invention

[0007] According to one aspect, the coverage of the TiSiN film can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 7

Figure 8

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Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0010] [TiSiN film] The TiN film (titanium nitride film) is used, for example, for the capacitor electrodes of memory cells. As the formation of the TiN film, for example, an ALD (Atomic Layer Deposition) method using TiCl4 (tetrachlorotitanium) gas as the Ti source gas and NH3 (ammonia) gas as the nitriding gas is used. Further, in order to improve the chemical resistance and oxidation resistance of the TiN film, the formation of a TiSiN film in which Si (silicon) is doped into the TiN film has been proposed.

[0011] FIG. 1 is a cross-sectional view showing an example of the film structure of the TiSiN film 201 formed on the surface of the substrate W. By repeating the step of alternately forming the TiN film 101 and the SiN film 102 on the surface of the silicon substrate 200 Z times, a TiSiN film 201 in which Z layers of the TiN film 101 and the SiN film 102 are alternately laminated is formed. As the formation of the SiN film, for example, an ALD method using SiH4 (silane) gas as the Si source gas and NH3 gas as the nitriding gas is used. Note that a CVD (Chemical Layer Deposition) method may be used for the formation of the TiN film and the SiN film.

[0012] Each layer of the TiN film 101 is formed by repeating the film formation sequence of the TiN film 101 X times. Each layer of the SiN film 102 is formed by repeating the film formation sequence of the SiN film 102 Y times. The film formation sequence of the TiN film 101 repeated X times is also referred to as the "TiN sequence", and the film formation sequence of the SiN film 102 repeated Y times is also referred to as the "SiN sequence". Then, the entire X - time - repeated TiN sequence and the Y - time - repeated SiN sequence are combined together and executed Z times. As a result, as shown in FIG. 1, a TiSiN film 201, which is a laminated film in which Z layers of the TiN film 101 and Z layers of the SiN film 102 are alternately laminated, is formed.

[0013] In the film formation of the TiSiN film 201, there may be a problem that the coverage of the SiN film 102 is inferior to that of the TiN film 101 due to the self - decomposition of the Si source gas. For example, in a substrate having a concave pattern due to the self - decomposition of the Si source gas, a large amount of the SiN film is formed on the upper surface side of the concave portion.

[0014] Therefore, a substrate processing method by ALD method that can improve the coverage of the SiN film in the TiSiN film is proposed. For example, the TiN film is formed by alternately supplying TiCl4 gas and NH3 gas X times. The SiN film is formed by alternately supplying SiH4 gas and NH3 gas Y times. At this time, by changing the ratio (hereinafter, also referred to as the "cycle ratio") of the number of repetitions X when forming one layer of the TiN film 101 and the number of repetitions Y when forming one layer of the SiN film 102, a TiSiN film with improved coverage can be formed while adjusting the silicon concentration.

[0015] Hereinafter, with reference to FIG. 2, an example of a substrate processing apparatus capable of executing the substrate processing apparatus will be described, and then with reference to FIGS. 3 and later, a substrate processing method for forming a TiSiN film with improved coverage will be described.

[0016] [Substrate Processing Apparatus] FIG. 2 is a schematic cross-sectional view showing an example of a substrate processing apparatus 10 according to an embodiment. The substrate processing apparatus 10 is an ALD apparatus that forms a TiSiN film 201, which is a laminated film of a TiN film 101 and a SiN film 102, on the surface of a substrate W, such as a wafer. The substrate processing apparatus 10 alternately repeats forming one layer of the TiN film 101 and then forming one layer of the SiN film 102 to form the TiSiN film 201 shown in FIG. 1.

[0017] The substrate processing apparatus 10 includes a processing chamber 1, a stage 2, a shower head 3, an exhaust unit 4, a processing gas supply unit 5, and a control device 7. The processing chamber 1 is made of a metal such as aluminum and has a substantially cylindrical shape. An inlet / outlet 11 for loading or unloading the substrate W is formed in the side wall of the processing chamber 1, and the inlet / outlet 11 can be opened and closed by a gate valve 12. An annular exhaust duct 13 having a substantially rectangular cross-section is provided on the main body of the processing chamber 1. A slit 13a is formed along the inner peripheral surface of the exhaust duct 13. Further, an annular exhaust space 13b is formed in the exhaust duct 13. An exhaust port 13c is formed in the outer wall of the exhaust duct 13. A top wall 14 is provided on the upper surface of the exhaust duct 13 so as to close the upper opening of the processing chamber 1. The space between the top wall 14 and the exhaust duct 13 is hermetically sealed by a seal ring 15.

[0018] The stage 2 horizontally supports the substrate W in the processing chamber 1. The stage 2 has a disk shape corresponding to the size of the substrate W and is supported by a support member 23. The stage 2 is made of a ceramic material such as aluminum nitride (AlN), or a metal material such as aluminum or a nickel-based alloy, and a heater 21 for heating the substrate W is embedded therein. The heater 21 is supplied with power from a heater power supply (not shown) and generates heat. Then, the output of the heater 21 is controlled by a temperature signal of a thermocouple (not shown) provided near the wafer placement surface on the upper surface of the stage 2, so as to control the substrate W to a predetermined temperature.

[0019] In stage 2, a cover member 22 made of ceramics such as alumina is provided so as to cover the outer peripheral region of the wafer mounting surface and the side surface of stage 2. The support member 23 extends downward from the center of the bottom surface of stage 2 through a hole formed in the bottom wall of the processing container 1 and is connected to a lifting mechanism 24 at its lower end. The lifting mechanism 24 enables stage 2 to move up and down via the support member 23 between the processing position shown in FIG. 1 and the transfer position where the wafer can be transferred shown by the two-dot chain line below it. Further, a flange portion 25 is attached below the processing container 1 of the support member 23, and a bellows 26 that partitions the atmosphere inside the processing container 1 from the outside air and expands and contracts as stage 2 moves up and down is provided between the bottom surface of the processing container 1 and the flange portion 25.

[0020] Near the bottom surface of the processing container 1, three (only two are shown) support pins 27 are provided so as to protrude upward from the lifting plate 27a. The support pins 27 can be moved up and down via the lifting plate 27a by a lifting mechanism 28 provided below the processing container 1, and are inserted into through holes 2a provided in stage 2 at the transfer position and can protrude and retract with respect to the upper surface of stage 2. By moving the support pins 27 up and down in this way, the substrate W is transferred between the wafer transfer mechanism (not shown) and stage 2.

[0021] The shower head 3 supplies the processing gas in a shower shape into the processing container 1. The shower head 3 is made of metal, is provided so as to face stage 2, and has substantially the same diameter as stage 2. The shower head 3 has a main body portion 31 fixed to the top wall 14 of the processing container 1 and a shower plate 32 connected below the main body portion 31. A gas diffusion space 33 is formed between the main body portion 31 and the shower plate 32, and a gas introduction hole 36 is provided in the gas diffusion space 33 so as to penetrate the centers of the main body portion 31 and the top wall 14 of the processing container 1. An annular protrusion 34 protruding downward is formed at the peripheral edge of the shower plate 32, and gas discharge holes 35 are formed in the flat surface inside the annular protrusion 34 of the shower plate 32.

[0022] In the state where the stage 2 is at the processing position, a processing space 37 is formed between the shower plate 32 and the stage 2, and an annular gap 38 is formed with the upper surface of the annular protrusion 34 and the cover member 22 of the stage 2 being close to each other. The width (length) of the gap between the lower surface of the annular protrusion 34 and the upper surface of the cover member 22 is indicated by "gap G".

[0023] The exhaust section 4 exhausts the interior of the processing vessel 1. The exhaust section 4 includes an exhaust line 41, a pressure adjustment section (APC: Auto Pressure Controller) 42, a valve 43, and a vacuum pump 44. One end of the exhaust line 41 is connected to the exhaust port 13c of the exhaust duct 13, and the other end is connected to the suction port of the vacuum pump 44. Between the exhaust duct 13 and the vacuum pump 44, the pressure adjustment section 42 and the valve 43 are provided in order from the upstream side. The pressure adjustment section 42 adjusts the pressure in the processing space 37 by adjusting the conductance of the exhaust path. The valve 43 switches the opening and closing of the exhaust line 41. During processing, the gas in the processing space 37 reaches the exhaust space 13b of the exhaust duct 13 through the annular gap 38 and the slit 13a, and is exhausted from the exhaust port 13c of the exhaust duct 13 by the vacuum pump 44 of the exhaust section 4 through the exhaust line 41.

[0024] The processing gas supply section 5 includes a Ti raw material gas supply line L1, a Si raw material gas supply line L2, an NH3 gas supply line L3, and a purge line L4.

[0025] The Ti raw material gas supply line L1 extends from a TiCl4 supply source GS1, which is a supply source of TiCl4 gas as the Ti raw material gas, for example, and is connected to a merging pipe L5. The merging pipe L5 is connected to the gas introduction hole 36. In the Ti raw material gas supply line L1, a mass flow controller (MFC) M1, a buffer tank T1, and an on-off valve V1 are provided in order from the TiCl4 supply source GS1 side. The mass flow controller M1 controls the flow rate of the TiCl4 gas flowing through the Ti raw material gas supply line L1. The buffer tank T1 temporarily stores the TiCl4 gas and supplies the required TiCl4 gas in a short time. The on-off valve V1 switches the supply and stop of the TiCl4 gas during the ALD process.

[0026] The Si raw material gas supply line L2 extends from an SiH4 supply source GS2, which is a supply source of SiH4 gas, for example, as the Si raw material gas, and is connected to the merging pipe L5. In the Si raw material gas supply line L2, a mass flow controller M2, a buffer tank T2, and an on-off valve V2 are provided in order from the SiH4 supply source GS2 side. The mass flow controller M2 controls the flow rate of the SiH4 gas flowing through the Si raw material gas supply line L2. The buffer tank T2 temporarily stores the SiH4 gas and supplies the necessary SiH4 gas in a short time. The on-off valve V2 switches the supply and stop of the SiH4 gas during the ALD process.

[0027] The NH3 gas supply line L3 extends from an NH3 gas supply source GS3, which is a nitrogen-containing gas, for example, as the NH3 gas, and is connected to the merging pipe L5. In the NH3 gas supply line L3, a mass flow controller M3, a buffer tank T3, and an on-off valve V3 are provided in order from the NH3 gas supply source GS3 side. The mass flow controller M3 controls the flow rate of the NH3 gas flowing through the NH3 gas supply line L3. The buffer tank T3 temporarily stores the NH3 gas and supplies the necessary NH3 gas in a short time. The on-off valve V3 switches the supply and stop of the NH3 gas during the ALD process.

[0028] The purge line L4 extends from an N2 gas supply source GS4, which is a supply source of N2 gas, and is connected to the merging pipe L5. The purge line L4 supplies N2 gas during the purge step in film formation by the ALD method. In the purge line L4, a mass flow controller M4, a buffer tank T4, and an on-off valve V4 are provided in order from the N2 gas supply source GS4 side. The mass flow controller M4 controls the flow rate of the N2 gas flowing through the purge line L4. The buffer tank T4 temporarily stores the N2 gas and supplies the necessary N2 gas in a short time. The on-off valve V4 switches the supply and stop of the N2 gas during the purge of the ALD process.

[0029] The top wall 14 is connected to an RF (Radio Frequency) power supply 50 via a matcher 51. The RF power supply 50 supplies high-frequency (RF) power for plasma generation.

[0030] The control device 7 controls the operations of each part of the substrate processing apparatus 10. The control device 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU executes substrate processing according to a recipe stored in a storage area such as the RAM. Various process conditions such as film formation conditions are set as control information for the apparatus in the recipe. The control information may be, for example, gas flow rate, pressure, temperature, and process time. Note that the recipe and the program used by the control device 7 may be stored in, for example, a hard disk or a semiconductor memory. Further, the recipe etc. may be set at a predetermined position in a state of being accommodated in a portable computer-readable storage medium such as a CD-ROM or a DVD and read out.

[0031] [Film Formation Method] Next, a substrate processing method for forming a TiSiN film in which a TiN film (titanium nitride film) and a SiN film (silicon nitride film) are laminated on the surface of a substrate by ALD (Atomic Layer Deposition) method will be described. FIG. 3 is an example of a flowchart showing an example of a substrate processing method according to an embodiment. The substrate processing method in FIG. 3 is controlled by the control device 7 and executed by the substrate processing apparatus 10.

[0032] First, in step S1, the substrate W is carried into the processing chamber 1 of the substrate processing apparatus 10. Specifically, with the stage 2 heated to a predetermined temperature (for example, 300°C to 700°C) by the heater 21 lowered to the transfer position (shown by a two-dot chain line in FIG. 1), the gate valve 12 is opened. Subsequently, the substrate W is carried into the processing chamber 1 through the carry-in outlet 11 by a transfer arm (not shown) and supported by the support pins 27. When the transfer arm retracts from the carry-in outlet 11, the gate valve 12 is closed. Further, the support pins 27 are lowered and the substrate W is placed on the stage 2 to prepare the substrate W.

[0033] Subsequently, in step S2, the stage 2 is raised to the processing position (indicated by the solid line in FIG. 2), and the gap G between the lower surface of the annular protrusion 34 and the upper surface of the cover member 22 is controlled. The gap G may be controlled to 0.5 mm or less.

[0034] Next, in step S3, the temperature of the substrate W on the stage 2 is raised, and the opening degree of the pressure adjustment unit 42 is adjusted. That is, the substrate W on the stage 2 is heated by the heater 21, for example, to 300°C to 700°C. Further, the control device 7 controls the exhaust unit 4 to adjust the inside of the processing container 1 to a predetermined degree of vacuum. Thereafter, the control device 7 opens the on-off valve V4 and closes the on-off valves V1 to V3. Thereby, N2 gas is supplied into the processing space 37 from the N2 gas supply source GS4 through the N2 gas supply line L4 to increase the pressure. Further, the control device 7 adjusts the opening degree of the pressure adjustment unit 42 so that the pressure in the processing space 37 becomes a desired pressure based on a pressure sensor (not shown) that detects the pressure in the processing space 37. At this time, TiCl4 gas is supplied from the TiCl4 supply source GS1 into the buffer tank T1, and the pressure in the buffer tank T1 is maintained substantially constant. SiH4 gas is supplied from the SiH4 supply source GS2 into the buffer tank T2, and the pressure in the buffer tank T2 is maintained substantially constant. NH3 gas is supplied from the NH3 gas supply source GS3 into the buffer tank T3, and the pressure in the buffer tank T3 is maintained substantially constant.

[0035] In step S4, a film forming process is executed. In this film forming process, a TiSiN film is formed on the substrate W, but the specific process will be described later. When the film forming process is completed, the process proceeds to step S5.

[0036] In step S5, the control device 7 controls the elevating mechanism 24 to lower the stage 2 to the transfer position.

[0037] In step S6, the substrate W is carried out from the processing chamber 1 of the substrate processing apparatus 10. Specifically, the support pins 27 are raised to lift the substrate W placed on the stage 2 and support it with the support pins 27. Also, the gate valve 12 is opened. Subsequently, the substrate W is carried out from the processing chamber 1 through the carry-in / outlet 11 by the inserted transfer arm (not shown). When the transfer arm retracts from the carry-in / outlet 11, the gate valve 12 is closed. Thus, the process of forming the TiSiN film on the substrate W in the substrate processing apparatus 10 is completed.

[0038] <First Embodiment> [Film Formation Example 1 of TiSiN Film] In the first embodiment, film formation example 1 of the TiSiN film in step S4 of FIG. 3 will be further described with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing an example of the film formation method according to the first embodiment. FIG. 5 is a time chart showing an example of the film formation method according to the first embodiment.

[0039] (Film Formation of TiN Film) Steps S11 to S15 in FIG. 4 show an example of the TiN sequence, and the TiCl4 gas and the NH3 gas are alternately supplied X times into the processing chamber 1 to form a TiN film by an ALD process.

[0040] In step S11, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V1 is opened, and the TiCl4 gas is supplied from the Ti raw material gas supply source GS1 to the processing space 37 through the Ti raw material gas supply line L1. At this time, the TiCl4 gas is once stored in the buffer tank T1 and then supplied into the processing chamber 1. Thereby, the TiCl4 gas is adsorbed on the surface of the substrate W.

[0041] Next, in step S12, surplus TiCl4 gas or the like in the processing space 37 is purged. In step S12, the on-off valve V1 is closed to stop the supply of TiCl4 gas. Also, the on-off valve V4 is in an open state, and N2 gas is supplied into the processing container 1 from the N2 gas supply source GS4 through the purge line L4. Thereby, the TiCl4 gas in the processing container 1 is replaced with N2 gas. Note that the purge gas is not limited to N2 gas and may be an inert gas such as Ar gas.

[0042] Next, in step S13, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V3 is opened, and NH3 gas is supplied from the NH3 gas supply source GS3 through the NH3 gas supply line L3 to the processing space 37. At this time, the NH3 gas is once stored in the buffer tank T3 and then supplied into the processing container 1. Thereby, NH3 gas is supplied to the surface of the substrate W. Thereby, a TiN film can be formed by heat treatment using the TiCl4 gas precursor.

[0043] Next, in step S14, surplus NH3 gas or the like in the processing space 37 is purged. In step S14, the on-off valve V3 is closed to stop the supply of NH3 gas. Also, the on-off valve V4 is in an open state, and N2 gas is supplied into the processing container 1 from the N2 gas supply source GS4 through the purge line L4. Thereby, the NH3 gas in the processing container 1 is replaced with N2 gas.

[0044] Next, in step S15, it is determined whether the set number X (X is a positive integer of 1 or more) has been repeated. In step S15, the processes of steps S11 to S15 are repeated until it is determined that the repetition has been performed X times. When it is determined in step S15 that the repetition has been performed X times, the process proceeds to step S16. Thereby, the first layer of the TiN film 101 with a desired film thickness is formed on the substrate W (see FIG. 1).

[0045] "TiN Xcycle (X = 4)" in Fig. 5 shows a time chart when steps S11 to S14 are repeated X times, i.e., 4 times, with one execution of steps S11 to S14 in the TiN sequence defined as one cycle.

[0046] (Film formation of SiN film) Steps S16 to S20 in Fig. 4 show an example of the SiN sequence, where SiH4 gas and NH3 gas are alternately supplied Y times into the processing vessel 1, and a SiN film is formed by an ALD process.

[0047] In step S16, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V2 is opened, and SiH4 gas is supplied from the Si raw material gas supply line L2 via the SiH4 supply source GS2 to the processing space 37. At this time, the SiH4 gas is once stored in the buffer tank T2 and then supplied into the processing vessel 1. Thereby, the SiH4 gas is adsorbed on the surface of the TiN film 101 of the substrate W.

[0048] Next, in step S17, the excess SiH4 gas and the like in the processing space 37 are purged. In step S17, the on-off valve V2 is closed to stop the supply of SiH4 gas. Also, the on-off valve V4 is open, and N2 gas is supplied from the N2 gas supply source GS4 into the processing vessel 1 via the purge line L4. Thereby, the SiH4 gas in the processing vessel 1 is replaced with N2 gas. Note that the purge gas is not limited to N2 gas and may be an inert gas such as Ar gas.

[0049] Next, in step S18, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V3 is opened, and NH3 gas is supplied from the NH3 gas supply source GS3 into the processing space 37 via the NH3 gas supply line L3. At this time, the NH3 gas is once stored in the buffer tank T3 and then supplied into the processing vessel 1. Thereby, the NH3 gas is supplied to the surface of the substrate W. Thereby, a SiN film can be formed by heat treatment using the precursor of the SiH4 gas.

[0050] Next, in step S19, surplus NH3 gas or the like in the processing space 37 is purged. In step S19, the on-off valve V3 is closed to stop the supply of NH3 gas. Also, the on-off valve V4 is in an open state, and N2 gas is supplied into the processing container 1 from the N2 gas supply source GS4 via the purge line L4. Thereby, the NH3 gas in the processing container 1 is replaced with N2 gas.

[0051] Next, in step S20, it is determined whether the set number of times Y (Y is a positive integer of 2 or more) has been repeated. In step S20, the processes of steps S16 to S20 are repeated until it is determined that the repetition has been performed Y times. When it is determined in step S20 that the repetition has been performed Y times, the process proceeds to step S21. Thereby, the first layer of the SiN film 102 with a desired film thickness is formed on the first layer of the TiN film 101 (see FIG. 1).

[0052] "SiN Ycycle (Y≧2)" in FIG. 5 shows a time chart when steps S16 to S19 are repeated Y times, that is, 2 times, with one execution of steps S16 to S19 in the SiN sequence being defined as one cycle.

[0053] Next, in step S21, it is determined whether steps S11 to S20 have been repeated the set number of times Z (Z is a positive integer of 1 or more). In step S21, the processes of steps S11 to S20 are repeated until it is determined that the repetition has been performed Z times. When it is determined in step S21 that the repetition has been performed Z times, this process ends. Thereby, a TiSiN film in which the TiN film 101 and the SiN film 102 are alternately laminated Z layers each is formed on the substrate W (see FIG. 1).

[0054] "Zcycle" in FIG. 5 indicates that with Z being a positive integer of 1 or more, the TiN sequence and the SiN sequence are combined and the whole is executed once as one cycle, and the process is repeated Z times (Z cycles).

[0055] As described above, the substrate processing method according to the first embodiment is a substrate processing method for forming a TiSiN film in which a TiN film and a SiN film are laminated on the surface of a substrate, including: (a) preparing the substrate on a stage in a processing chamber; (b) alternately supplying a Ti source gas containing a Ti source and a nitriding gas into the processing chamber X times to form a TiN film; (c) alternately supplying a Si source gas containing a Si source and a nitriding gas into the processing chamber Y times to form a SiN film; and (d) executing (b) and (c) in this order Z times. Here, X and Z may be integers of 1 or more, and Y may be an integer of 2 or more.

[0056] The fact that Y is 2 or more, that is, the SiN sequence is repeated 2 or more times, will be described based on the experimental results of FIGS. 6 to 8.

[0057] [Experimental Result 1] Figure 6 shows Experimental Result 1. Figure 6 is a graph showing an example of the experimental results of the coverage of the SiN film with respect to the cycle ratio of X and Y (the ratio of X, which is the number of repetitions when forming one layer of the TiN film, and Y, which is the number of repetitions when forming one layer of the SiN film). According to this, when the TiN sequence is repeated X times and the SiN sequence is repeated Y times, as the ratio of Y to X increases, it does not happen that the SiN film 102 with worse coverage than the TiN film 101 continues to be laminated. The SiN film 102 was thinly formed and continued to complement the remaining adsorption sites on the surface of the TiN film 101. As a result, the coverage of the SiN film 102 was improved. In other words, for the TiN:SiN on the horizontal axis, that is, the cycle ratio of X:Y, as the ratio of Y to X increases as 4:1, 4:10, 4:20, etc., once the SiN film is formed, the SiH4 gas does not adsorb near the upper surface or the opening of the concave portion 202 where there are no remaining adsorption sites on the surface of the TiN film 101, and adsorbs at the bottom of the concave portion 202 where there are remaining adsorption sites on the surface of the TiN film 101. Therefore, finally, a SiN film 102 with good coverage could be formed. As a result, as shown on the vertical axis of Figure 6, the higher the ratio of Y to X, the more the step coverage (step coverage property) of the SiN film 102 with respect to the pattern of the concave portion 202 could be improved.

[0058] [Experimental Result 2] Figure 7 shows Experimental Result 2. Figure 7 is a graph showing an example of the experimental results of the film formation rate of the Z cycle with respect to the cycle ratio of X and Y. The horizontal axis of Figure 7 shows the cycle ratio. The description "TiN:SiN = 4:Y (cycles)" on the horizontal axis indicates that in this experiment, X was fixed at "4" and Y was changed to the numerical value on the horizontal axis for the experiment.

[0059] The vertical axis of Figure 7 shows the film formation rate per cycle of forming the TiN film and the SiN film one by one as the Z cycle rate in the formation of the TiSiN film in which the TiN film and the SiN film are formed in Z layers. The Z cycle rate is the total film thickness of the TiN film and the SiN film per cycle.

[0060] According to the graph of FIG. 7, with X fixed at 4, the Z cycle rate increases as Y increases. However, when Y is 2 or more, the Z cycle rate does not change much with the increase of Y. That is, in the example of FIG. 7, it was found that by setting Y to 2 or more, the coverage of the SiN film 102 can be sufficiently improved.

[0061] FIG. 8 is a cross-sectional view of a film showing an example of the coverage effect of the SiN film on the cycle ratio of X and Y. For example, in FIG. 8(a), when the number of repetitions X of the TiN film 101 is 4 and the number of repetitions Y of the SiN film 102 is 1, the SiN film 102 is formed on the upper surface of the recess 202 formed in the substrate W and the side surfaces near the opening. On the other hand, the SiN film 102 was not sufficiently formed on the bottom surface of the recess 202 and the side surfaces near the bottom. The TiN film 101 is formed with good coverage on the upper surface, side surface and bottom surface of the recess 202 by setting the number of repetitions X to 4.

[0062] In contrast, in FIG. 8(b), when X remains 4 and Y is 20, the SiN film 102 is sufficiently formed on the upper surface, side surface and bottom surface of the recess 202, and the coverage of the SiN film 102 is improved.

[0063] Consider the control of the cycle ratio of X and Y by these experiments and the reason for the improvement of the coverage of the SiN film. When Y is 1 with respect to X being 4, due to the self-decomposition of the SiH4 gas, the SiN film 102 is easily formed on the upper surface of the recess 202 where the SiH4 gas can easily reach and the side surfaces near the opening. On the other hand, it is difficult for the SiH4 gas to reach the bottom of the recess 202, and it is difficult to form the SiN film 102. In contrast, when Y increases to 20, the SiH4 gas also reaches the bottom of the recess 202 where there are remaining adsorption sites on the surface of the TiN film 101, and the SiN film 102 is formed at the bottom of the recess 202. On the other hand, the SiN film 102 is not formed on the SiN film 102 on the upper surface of the recess 202 where the SiN film 102 has been formed or near the opening. From this, it can be seen that for the adsorption of the SiH4 gas, the surface of the TiN film 101 on which the SiN film 102 is not formed is required. From the above, when Y is 2 or more, the coverage of the SiN film can be improved.

[0064] [Experimental Result 3] Figure 9 is a graph showing an example of the experimental results of the coverage of the SiN film 102 with respect to the cycle ratio and the gap G. SiN / (TiN+SiN) on the horizontal axis of Figure 9 is the ratio of the number of SiN cycles Y to the total number of cycles (X+Y). The vertical axis indicates the step coverage (step coverage property in the pattern of the recess).

[0065] The dashed-dotted line A (hatched 〇) in the graph of Figure 9 shows the step coverage when, for the film formation conditions of the SiN film, the gap G is 0.5 mm, the stage temperature (temperature of the heater 21) is 520 °C, the cycle ratio of TiN:SiN (X:Y) is 4:Y, X is fixed at 4, and Y is changed. Also, the numerical values indicated by % in the graph represent the Si concentration in the TiSiN film.

[0066] The two-dot chain line B (black ●) indicates that the gap G is 3 mm, and the other film formation conditions of the SiN film are the same as those of the dashed-dotted line A.

[0067] The broken line C (white 〇) shows the step coverage when the cycle ratio of TiN:SiN (X:Y) is 1:Y, X is fixed at 1, and Y is changed. The other film formation conditions of the SiN film are the same as those of the two-dot chain line B.

[0068] The point D (△) shows the step coverage when, for the film formation conditions of the SiN film, the gap G is 3 mm, the stage temperature is 440 °C, and the cycle ratio of TiN:SiN (X:Y) is fixed at 1:5.

[0069] The solid line E (white 〇) shows the step coverage when the TiN film is formed at a stage temperature of 520 °C. The step coverage of the TiN film is as high as about 95%. In contrast, the coverage of the SiN film 102 is relatively poor.

[0070] From the perspective of productivity, it is important to form a SiN film with good step coverage while minimizing the cycle ratio of the SiN film to the TiN film as much as possible. For this purpose, as shown by the dashed line A and the dotted line B, it has been found that the cycle number X of the TiN film is preferably 4 or more.

[0071] Conversely, considering the cases of point D where the cycle number X of the TiN film is 1 and the dashed line C, if X is set to 1 and the TiN sequence is performed only once, generally, the TiN film 101 formed by the single-wafer substrate processing apparatus 10 shown in FIG. 2 has an island structure that is less than a monolayer. FIG. 10(a) schematically shows a case where the cycle ratio of TiN:SiN (X:Y) is 1:Y and the TiN film 101 is a discontinuous film with an island structure. In this case, since the surface area of the TiN film 101 increases and the adsorption area of the SiH4 gas increases, more SiH4 gas needs to be supplied until the coverage of the SiN film 102 improves. Therefore, from the perspective of forming the SiN film 102 with good coverage using less Si raw material, it is disadvantageous. Thus, as a guideline for one monolayer of the TiN film 101, in the single-wafer substrate processing apparatus 10, it is preferable that the TiN film 101 has 4 or more cycles. As a result, as shown in FIG. 10(b), when the cycle ratio of TiN:SiN (X:Y) is 4:Y, the TiN film 101 is in a state of a continuous film with one monolayer formed, and the surface area of the TiN film 101 can be reduced. Thereby, by supplying less SiH4 gas onto the TiN film 101, a SiN film 102 with good coverage can be formed.

[0072] From the above, for example, the cycle ratio of TiN:SiN (X:Y) is controlled such that Y is 2 times or more of X, such as 1:5, 4:10, etc. At this time, by controlling X as an integer of 1 or more and Y as an integer of 2 or more, the coverage of the SiN film 102 can be improved. Furthermore, it is more preferable to control X to be 4 or more. Since the TiN film 101 becomes a continuous film, a SiN film 102 with good coverage can be formed by supplying less SiH4 gas.

[0073] According to the film formation method according to the first embodiment, when forming a TiSiN film by combining a TiN sequence and a SiN sequence, the cycle ratio (X:Y) of X and Y, which are the number of repetitions of the TiN sequence and the SiN sequence, is controlled. X is controlled to be an integer of 1 or more, and Y is controlled to be an integer of 2 or more. By controlling the cycle ratio (X:Y), the step coverage of the SiN film 102 can be improved. Thereby, a TiSiN film 201 with good coverage can be formed.

[0074] Furthermore, X is preferably the number of times the TiN film becomes a continuous film, and is preferably 4 or more. Thereby, even if the supply amount of the Si raw material gas is made smaller, a TiSiN film 201 with good coverage can be formed.

[0075] <Second Embodiment> [Film Formation Example 2 of TiSiN Film] Next, Film Formation Example 2 of the TiSiN film in step S4 of FIG. 3 will be further described with reference to FIGS. 11 and 12. FIG. 11 is a flowchart showing an example of the film formation method according to the second embodiment. FIG. 12 is a time chart showing an example of the film formation method according to the second embodiment.

[0076] In FIG. 11, the same step numbers are assigned to the steps that perform the same processing as the steps of the film formation method according to the first embodiment shown in FIG. 4, and the description of the processing with the same step numbers is omitted or simplified.

[0077] (Film Formation of TiN Film) Steps S11 to S15 in FIG. 11 are steps of alternately supplying TiCl4 gas and NH3 gas into the processing vessel 1 X times and forming a TiN film by an ALD process, which are the same steps as in the first embodiment.

[0078] "TiN Xcycle (X = 4)" in FIG. 12 shows a time chart when steps S11 to S14 are repeated 4 cycles with one cycle being the execution of steps S11 to S14 once in the TiN sequence.

[0079] Steps S36 to S41 in FIG. 11 are steps of forming a SiN film by an ALD process by supplying SiH4 gas Y times into the processing vessel 1 and then supplying NH3 gas once. This group of steps is different from the first embodiment in which SiH4 gas and NH3 gas are alternately supplied Y times to form a SiN film by an ALD process.

[0080] In step S36, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V2 is opened, and SiH4 gas is supplied from the Si raw material gas supply source GS2 to the processing space 37 through the Si raw material gas supply line L2. At this time, the SiH4 gas is once stored in the buffer tank T2 and then supplied into the processing vessel 1. Thereby, the SiH4 gas is adsorbed on the surface of the TiN film 101 of the substrate W.

[0081] Next, in step S37, the excess SiH4 gas and the like in the processing space 37 are purged. In step S37, the on-off valve V2 is closed to stop the supply of SiH4 gas. Also, the on-off valve V4 is open, and N2 gas is supplied from the N2 gas supply source GS4 into the processing vessel 1 through the purge line L4. Thereby, the SiH4 gas in the processing vessel 1 is replaced with N2 gas.

[0082] Next, in step S38, it is determined whether steps S36 to S37 have been repeated the set number Y (Y is an integer of 2 or more). In step S38, the processes of steps S36 to S37 are repeated until it is determined that they have been repeated Y times. When it is determined in step S38 that they have been repeated Y times, the process proceeds to step S39. Thereby, the first layer of the SiN film 102 with a desired film thickness is formed on the first layer of the TiN film 101 of the substrate W (see FIG. 1).

[0083] Next, in step S39, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V3 is opened, and NH3 gas is supplied from the NH3 gas supply source GS3 to the processing space 37 through the NH3 gas supply line L3. At this time, the NH3 gas is once stored in the buffer tank T3 and then supplied into the processing container 1. Thereby, the NH3 gas is supplied to the surface of the substrate W. Thereby, a SiN film can be formed.

[0084] Next, in step S40, the excess NH3 gas and the like in the processing space 37 are purged. In step S40, the on-off valve V3 is closed to stop the supply of NH3 gas. Also, the on-off valve V4 is open, and N2 gas is supplied from the N2 gas supply source GS4 into the processing container 1 through the purge line L4. Thereby, the NH3 gas in the processing container 1 is replaced with N2 gas.

[0085] "SiN Ycycle (Y≥2)" in FIG. 12 means that in the SiN sequence, one cycle is defined as executing steps S36 to S37 once, and after steps S36 to S37 are repeated Y times, that is, two or more times, steps S39 to S40 are executed once. This shows the time chart when forming the SiN film.

[0086] Next, in step S41, it is determined whether steps S11 to S15 and S36 to S40 have been repeated a set number of times Z (Z is a positive integer). In step S41, until it is determined that the repetition has been Z times, the processes of S11 to S15 and S36 to S40 are repeated (refer to Zcycle in FIG. 12). When it is determined in step S41 that the repetition has been Z times, this process ends. Thereby, a TiSiN film in which the TiN film 101 and the SiN film 102 are alternately laminated Z layers each is formed on the substrate W (refer to FIG. 1).

[0087] As described above, the substrate processing method according to the second embodiment is a substrate processing method for forming a TiSiN film in which a TiN film and a SiN film are laminated on the surface of a substrate, including: (a) preparing the substrate on a stage in a processing chamber; (b) alternately supplying an X number of times a Ti source gas containing a Ti source and a nitriding gas into the processing chamber to form a TiN film; (c) supplying a Si source gas containing a Si source and a nitriding gas into the processing chamber, and after supplying the Si source gas Y number of times, supplying the nitriding gas to form a SiN film; and (d) executing (b) and (c) in this order Z number of times. Here, X and Z may be integers of 1 or more, and Y may be an integer of 2 or more.

[0088] According to the film formation method according to the second embodiment, when forming a TiSiN film by combining a TiN sequence and a SiN sequence, the cycle ratio (X:Y) between the TiN film sequence and the SiN sequence is controlled. X is controlled to be an integer of 1 or more, and Y is controlled to be an integer of 2 or more. Thereby, the coverage of the TiSiN film can be improved. In addition, the same effects as those of the film formation method according to the first embodiment can be obtained.

[0089] Furthermore, in the SiN sequence (FIG. 12) according to the second embodiment, since the SiH4 gas is repeatedly supplied Y number of times and then the NH3 gas is supplied only once, the execution time of the SiN sequence can be shortened.

[0090] <The Third Embodiment> [Film Formation Example 3 of TiSiN Film] Next, the film formation example 3 of the TiSiN film in step S4 of FIG. 3 will be further described with reference to FIGS. 13 and 14. FIG. 13 is a flowchart showing an example of the film formation method according to the third embodiment. FIG. 14 is a time chart showing an example of the film formation method according to the third embodiment.

[0091] In FIG. 13, the same step numbers are assigned to the steps that perform the same processing as those in the film formation method according to the first embodiment shown in FIG. 4, and the description of the processing with the same step numbers is omitted or simplified.

[0092] (Deposition of TiN film) Steps S11 to S15 in FIG. 13 are steps of alternately supplying TiCl4 gas and NH3 gas into the processing vessel 1 X times and forming a TiN film by an ALD process, which are the same steps as those in the first embodiment.

[0093] "TiN Xcycle (X = 4)" in FIG. 14 shows a time chart when steps S11 to S14 are repeated 4 cycles, with one execution of steps S11 to S14 defined as one cycle in the TiN sequence.

[0094] Steps S46 to S51 in FIG. 14 are steps of supplying SiH4 gas into the processing vessel 1 Y times and then supplying NH3 gas once to form a SiN film by an ALD process, where Y can be 1 or more. In this regard, it is different from the first and second embodiments where Y is 2 or more.

[0095] In step S46, with the on-off valve V4 open, the on-off valves V1 to V3 closed, the on-off valve V2 is opened, and SiH4 gas is supplied from the SiH4 supply source GS2 to the processing space 37 through the Si raw material gas supply line L2. At this time, the SiH4 gas is once stored in the buffer tank T2 and then supplied into the processing vessel 1. Thereby, the SiH4 gas is adsorbed on the surface of the TiN film 101 of the substrate W.

[0096] Next, in step S47, the excess SiH4 gas and the like in the processing space 37 are purged. In step S47, the on-off valve V2 is closed to stop the supply of SiH4 gas. Also, the on-off valve V4 is open, and N2 gas is supplied from the N2 gas supply source GS4 into the processing vessel 1 through the purge line L4. Thereby, the SiH4 gas in the processing vessel 1 is replaced with N2 gas.

[0097] Next, in step S48, with the on-off valve V4 open and the on-off valves V1 to V3 closed, the on-off valve V3 is opened, and NH3 gas is supplied from the NH3 gas supply source GS3 to the processing space 37 through the NH3 gas supply line L3. At this time, the NH3 gas is once stored in the buffer tank T3 and then supplied into the processing container 1. Thereby, the NH3 gas is supplied to the surface of the substrate W. As a result, the following chemical reaction occurs by heat treatment using the precursor of SiH4 gas, and a SiN film can be formed. 6SiH4(g)+32NH3(g)=6SiN+24NH5+N2(g)

[0098] Next, in step S49, the excess NH3 gas and the like in the processing space 37 are purged. In step S49, the on-off valve V3 is closed to stop the supply of NH3 gas. Also, the on-off valve V4 is in the open state, and N2 gas is supplied from the N2 gas supply source GS4 into the processing container 1 through the purge line L4. Thereby, the NH3 gas in the processing container 1 is replaced with N2 gas.

[0099] Next, in step S50, it is determined whether the time of the SiN sequence (the film formation time of the SiN film), that is, the time of steps S46 to S49 (the cumulative time of steps S46 to S49 when Y is 2 or more), is twice or more the time per cycle of the TiN sequence (the film formation time per cycle of the TiN film), that is, the time per cycle of steps S11 to S14.

[0100] In step S50, if it is determined that the time of the SiN sequence is less than twice the time per cycle of the TiN sequence, the process returns to step S46 to repeat the SiN sequence. In step S50, if it is determined that the time of the SiN sequence is twice or more the time per cycle of the TiN sequence, the process proceeds to step S51.

[0101] "SiN Ycycle (Y = 1)" in Fig. 14 shows the time chart when forming a SiN film by executing steps S46 to S50 once in the SiN sequence. When the time for one cycle of the TiN film sequence is 2 seconds, the time of the SiN sequence is 4 seconds or more.

[0102] Next, in step S51, it is determined whether steps S11 to S15 and S46 to S50 have been repeated a set number Z (Z is a positive integer). In step S51, the processes of S11 to S15 and S46 to S50 are repeated (refer to Zcycle in Fig. 14) until it is determined that they have been repeated Z times. When it is determined in step S51 that they have been repeated Z times, this process ends. Thereby, a TiSiN film in which the TiN film 101 and the SiN film 102 are alternately laminated Z layers each is formed on the substrate W (refer to Fig. 1).

[0103] As described above, the substrate processing method according to the third embodiment is a substrate processing method for forming a TiSiN film in which a TiN film and a SiN film are laminated on the surface of a substrate, including: (a) preparing the substrate on a stage in a processing container; (b) alternately supplying a Ti source gas containing a Ti source and a nitriding gas into the processing container X times to form a TiN film; (c) supplying a Si source gas containing a Si source and a nitriding gas into the processing container, and supplying the Si source gas at least Y times to form a SiN film; and (d) executing (b) and (c) in this order for Z cycles. Here, X, Y, and Z may be integers of 1 or more. Also, the time of (c) may be 2 times or more the time per cycle of (b).

[0104] According to the film formation method according to the third embodiment, when forming a TiSiN film by combining a TiN sequence and a SiN sequence, the time of the SiN sequence (when Y is 2 or more, the cumulative time of the SiN sequence) is controlled to be 2 times or more the time per cycle of the TiN sequence. X and Y are 1 or more. In the third embodiment, Y may be set once. By controlling the time of the SiN sequence to be 2 times or more the time per cycle of the TiN sequence, the supply amount of SiH4 gas is increased, and a SiN film with good coverage can be formed. Thereby, the coverage of the TiSiN film can be improved. In addition, the same effects as the film formation methods according to the first and second embodiments can be obtained.

[0105] [Others] In the substrate processing methods of the first to third embodiments, the Ti source gas containing a Ti source is a gas containing Ti such as TiCl4 and TiBr4.

[0106] In addition, the Si source gas containing a Si source is a gas containing Si such as SiH4 (silane), Si2H6 (disilane), SiH2Cl2 (dichlorosilane), or SiCl4.

[0107] In addition, the nitriding gas used in the sequence of the TiN film and the nitriding gas used in the SiN sequence are gases containing N such as NH3, N2H4, NH(CH3)2, or N2H3CH3. The nitriding gas used in the sequence of the TiN film and the nitriding gas used in the SiN sequence may be the same gas or different gases.

[0108] The substrate processing apparatus disclosed in this specification can be applied to any of a single wafer apparatus that processes substrates one by one, a batch apparatus that processes a plurality of substrates collectively, and a semi-batch apparatus.

[0109] As described above, according to the substrate processing methods of the first to third embodiments, the coverage of the TiSiN film can be improved.

[0110] The substrate processing method and substrate processing apparatus according to the embodiments disclosed this time should be considered as illustrative and not restrictive in all respects. The embodiments can be modified and improved in various forms without departing from the scope and gist of the appended claims. The matters described in the above-described multiple embodiments can also adopt other configurations within a non-contradictory range, and can be combined within a non-contradictory range.

Explanation of Reference Numerals

[0111] 1...Processing container, 2...Stage, 3...Shower head, 5...Processing gas supply unit, 7...Control device, 10...Substrate processing apparatus, 101...TiN film, 102...SiN film, 201...TiSiN film, 202...Recessed portion, L1...Ti raw material gas supply line, L2...Si raw material gas supply line, L3...NH3 gas supply line, L4...Purge line, L5...Confluence pipe

Claims

1. A substrate processing method for forming a TiSiN film in which a titanium nitride film and a silicon nitride film are laminated on the surface of a substrate, comprising: (a) preparing the substrate on a stage in a processing chamber; (b) alternately supplying an X number of times a Ti source gas containing a Ti source and a nitriding gas into the processing chamber to form the titanium nitride film; (c) supplying a Si source gas containing a Si source and a nitriding gas into the processing chamber, the Si source gas being supplied at least Y number of times to form the silicon nitride film; and (d) performing steps (b) and (c) in this order Z number of times, wherein X and Z are integers of 1 or more, and Y is an integer of 2 or more. A substrate processing method.

2. A substrate processing method for forming a TiSiN film in which a titanium nitride film and a silicon nitride film are laminated on the surface of a substrate, comprising: (a) preparing the substrate on a stage in a processing chamber; (b) alternately supplying an X number of times a Ti source gas containing a Ti source and a nitriding gas into the processing chamber to form the titanium nitride film; (c) supplying a Si source gas containing a Si source and a nitriding gas into the processing chamber, the Si source gas being supplied at least Y number of times to form the silicon nitride film; and (d) performing steps (b) and (c) in this order Z number of times, wherein X, Y, and Z are integers of 1 or more, and the time of step (c) is 2 times or more the time per one time of step (b). A substrate processing method.

3. In step (c), the Si source gas and the nitriding gas are alternately supplied Y number of times. The substrate processing method according to claim 1.

4. In step (c), after supplying the Si source gas Y number of times, the nitriding gas is supplied. The substrate processing method according to claim 1.

5. X is the number of times the titanium nitride film becomes a continuous film. The substrate processing method according to any one of claims 1 to 4.

6. X is 4 or more. The substrate processing method according to any one of claims 1 to 4.

7. Steps (b) and (c) are performed by an ALD method. The substrate processing method according to any one of claims 1 to 4.

8. The gap between the cover member of the stage and the annular protrusion of the shower head facing the stage is 0.5 mm or less. The substrate processing method according to any one of claims 1 to 4.

9. The substrate processing method according to any one of claims 1 to 4.

10.

11.

12.

13.

14. The Ti source gas is either TiCl ４ or TiBr ４ one of them,

15.

16. The Si raw material gas is SiH ４ , Si ２ H ６ , SiH ２ Cl ２ or SiCl ４ and is any one of them. The substrate processing method according to any one of claims 1 to 4.

11. The nitriding gas is NH ３ , N ２ H ４ , NH(CH ３ ), ２ or N ２ H ３ CH ３ and is any one of them. The substrate processing method according to any one of claims 1 to 4.

12. A substrate processing apparatus having a control unit, A substrate processing apparatus that executes the substrate processing method according to any one of claims 1 to 4 under the control of the control unit.

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