Apparatus for performing substrate processing, gas shower head, and method for performing substrate processing

Abstract

To provide a technique for accurately and speedily measuring pressure in a gas shower head.SOLUTION: In an apparatus that supplies processing gas to a substrate to process the substrate, the substrate is mounted on a mount table provided in a processing vessel, and a gas shower head provided opposite the mount table supplies the processing gas diffused in a gas diffusion space therein into the processing vessel through a plurality of gas supply holes formed in a shower plate. A gas supply part for supplying the processing gas into the gas diffusion space comprises a flow rate control part for the processing gas, and a pressure sensor part is provided in the gas diffusion space and outputs a pressure signal corresponding to a pressure measured value in the gas diffusion space. Then, a control part outputs a control signal for controlling the flow rate of the processing gas to the flow rate control part based upon the pressure measured value acquired from the pressure sensor part through the pressure signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for performing substrate processing, a gas showerhead, and a method for performing substrate processing. [Background technology]

[0002] CVD (Chemical Vapor Deposition) and ALD (Atomic Layer Deposition) are well-known processes for forming films on semiconductor wafers (hereinafter referred to as "wafers") in the manufacturing process of semiconductor devices. These film formation processes use source gases containing film raw materials and reactive gases that oxidize or reduce the source gases (hereinafter collectively referred to as "film formation gases").

[0003] Patent Document 1 describes a technique for efficiently mixing source gases with low vapor pressure and supplying them to a showerhead by providing a pressure gauge on the showerhead to measure the pressure. The diagram in Patent Document 1 shows that the pressure gauge is provided outside the showerhead and connected to the showerhead via a tube. Patent Document 2 also describes that a pressure sensor may be connected to a showerhead having multiple plenum volumes for use in semiconductor processing equipment. Besides film formation processes, gas showerheads are also used to supply process gases in etching processes, modification processes, and the like. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-252219 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-15466 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides techniques for accurately and quickly measuring pressure within a gas showerhead. [Means for solving the problem]

[0006] The present disclosure provides an apparatus for performing substrate processing by supplying a processing gas to a substrate in a processing vessel, the apparatus comprising: a mounting table provided in the processing chamber for mounting the substrate thereon; a gas shower head provided at a position facing the mounting table, the gas shower head including: a gas diffusion space for diffusing the processing gas; and a shower plate having a plurality of gas supply holes formed therein for supplying the processing gas diffused in the gas diffusion space into the processing vessel; a gas supply unit provided for supplying the processing gas to the gas diffusion space and including a flow rate regulator for the processing gas; a pressure sensor unit that is provided in the gas diffusion space and outputs a pressure signal corresponding to a pressure measurement value in the gas diffusion space; a control unit that outputs a control signal to the flow rate adjustment unit to adjust the flow rate of the processing gas based on the pressure measurement value acquired from the pressure sensor unit via the pressure signal. 、 the gas showerhead includes a plurality of the gas diffusion spaces separated from each other by partition walls; the pressure sensor units are provided directly within the plurality of diffusion spaces, the plurality of gas supply holes are provided in the plurality of diffusion spaces, respectively, so that the processing gas is supplied into the processing vessel from these diffusion spaces independently of each other; It is a device. [Effects of the Invention]

[0007] According to the present disclosure, the pressure inside a gas showerhead can be measured accurately and quickly. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional side view of a film forming apparatus according to an embodiment of the present disclosure. [Figure 2] 1A and 1B are an enlarged vertical cross-sectional view of a gas shower head according to an embodiment and a configuration diagram of a gas supply control device. [Figure 3]FIG. 1 is a cross-sectional plan view of a gas shower head according to an embodiment. [Figure 4] 1 illustrates a first configuration example of a pressure sensor according to an embodiment. [Figure 5] 10 is a second configuration example of a pressure sensor according to an embodiment. [Figure 6] A block diagram showing an electrical configuration of a film forming apparatus according to an embodiment. [Figure 7] FIG. 1 is a diagram illustrating the operation of film formation by the ALD method. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Film forming equipment> 1 to 6, a configuration of a film formation apparatus 1 that forms a film as substrate processing on a substrate, i.e., a wafer W, will be described as one embodiment of an apparatus for performing substrate processing. The film formation apparatus 1 is configured to supply a film formation gas as a processing gas into a processing chamber 11 that accommodates and processes the wafer W, and to form a film by atomic layer deposition (ALD).

[0010] In the ALD method, a film is formed by alternately supplying a source gas and a reactive gas multiple times. In the following example, a case where a silicon oxide (SiO2) film is formed on a wafer W will be described. Examples of the source gas containing the raw material (precursor) of the SiO2 film include gases such as Si2Cl6, Si2H6, HCDS (hexachlorodisilane), TDMAS (tridimethylaminosilane), and BDEAS (bisdiethylaminosilane).

[0011] Examples of reactive gases that react with the raw materials to obtain a SiO2 film include oxidizing gases such as oxygen (O2) gas and ozone (O3) gas. The reactive gas, for example, O2 gas, is converted into plasma and supplied to the wafer W, and the film forming apparatus 1 is configured as a plasma ALD apparatus. The reactive gas is not limited to the example of an oxidizing gas (O2 gas or O3 gas) for obtaining an oxide film (SiO2 film in the above example). An appropriate reactive gas is selected depending on the film to be formed on the wafer W and the nature of the reaction with the source gas. For example, nitrogen (N2) gas or ammonia (NH3) gas may be selected when obtaining silicon nitride. Furthermore, it is not essential that the reactive gas be turned into plasma. For example, a film may be formed by a thermal reaction on the surface of a heated wafer W.

[0012] In this example, the processing vessel 11 has a generally flat circular shape, and its sidewall is provided with a wafer loading / unloading port 12 and a gate valve 13 that opens and closes the loading / unloading port 12. An exhaust duct 14, which forms part of the sidewall of the processing vessel 11, is provided above the loading / unloading port 12. A slit-shaped opening 15 extending circumferentially is formed on the inner peripheral surface of the exhaust duct 14. The opening 15 constitutes an exhaust port for the processing vessel 11. One end of an exhaust pipe 16 is connected to the exhaust duct 14, and the other end of the exhaust pipe 16 is connected to an exhaust mechanism 17 consisting of a vacuum pump via a pressure adjustment mechanism 171 and a valve 172.

[0013] A disk-shaped mounting table 31 for horizontally mounting a wafer W is provided within the processing vessel 11. A heater for heating the wafer W and a grounded electrode plate can be embedded within the mounting table 31. The heater and the electrode plate are not shown in the figure.

[0014] The upper end of a rod-shaped support member 34, which penetrates the bottom of the processing vessel 11 and extends in the vertical direction, is connected to the center of the underside of the mounting table 31. The lower end of the support member 34 is connected to an elevation mechanism 35. The elevation mechanism 35 allows the mounting table 31 to move up and down between a lower position indicated by a dashed line in FIG. 1 and an upper position indicated by a solid line in the same figure. The lower position is a transfer position for transferring the wafer W to and from a transfer mechanism (not shown) for transferring the wafer W into the processing vessel 11 from the loading / unloading port 12. The upper position is a processing position where a film is formed on the wafer W.

[0015] In Fig. 1, reference numeral 36 denotes a flange, and reference numeral 37 denotes an expandable bellows. Reference numeral 38 denotes support pins for the wafer W, and there are, for example, three support pins 38 (only two are shown in the figure). Reference numeral 39 denotes a lifting mechanism that raises and lowers the support pins 38. When the mounting table 31 is positioned at the transfer position, the support pins 38 are raised and lowered through the through-holes 19 formed in the mounting table 31, causing the support pins 38 to protrude and retract from the upper surface of the mounting table 31. This operation allows the wafer W to be transferred between the mounting table 31 and the transfer mechanism.

[0016] <Gas shower head> A gas shower head 4 is provided on the exhaust duct 14 at a position facing the wafer W placed on the mounting table 31. In this example, the gas shower head 4 includes a top plate member 41 provided to close an opening formed on the upper surface of the processing chamber 11, and a shower plate 42 provided on the lower surface of the top plate member 41. The shower plate 42 is formed in a disk shape and is disposed to face the mounting table 31.

[0017] A flat gas diffusion space 43 for diffusing a film forming gas therein is formed between the top plate member 41 and the shower plate 42. A large number of gas discharge holes 45 are formed in a dispersed manner in the shower plate 42, and the processing gas diffused in the gas diffusion space 43 can be supplied into the processing vessel 11. 1 and 2, in this example, the periphery of the shower plate 42 is supported by an annular protrusion 44 that protrudes downward from the lower surface of the top plate member 41. The lower end of this annular protrusion 44 protrudes to a position close to the upper surface of the periphery side of the mounting table 31 that is placed at the processing position.

[0018] 2, the gas diffusion space 43 of the gas shower head 4 is partitioned into a plurality of sections by partition walls 46, and has a plurality of partitioned regions Z1 to Z3 from which gas can be independently discharged from the gas discharge holes 45. As shown in FIG. 3, the gas diffusion space 43 of this example is partitioned into a plurality of concentric sections by the partition walls 46 in correspondence with the radial direction of the wafer W placed on the mounting table 31.

[0019] That is, when viewed from the mounting table 31 side, the arrangement area of ​​the numerous gas ejection holes 45 in the shower plate 42 is divided into three partitioned areas (a first partitioned area Z1, a second partitioned area Z2, and a third partitioned area Z3) in the radial direction. In other words, the gas shower head 4 of this example includes a plurality of gas diffusion spaces 43.

[0020] In the following description, the gas diffusion space 43 partitioned from one another in the gas shower head 4 will also be referred to as the first to third partitioned regions Z1 to Z3. These first to third partitioned regions Z1 to Z3 are formed by concentrically dividing the shower plate 42, which is circular in plan view. Therefore, in terms of their respective planar shapes, the first partitioned region Z1 is circular, and the second and third partitioned regions Z2 and Z3 are annular. Note that the gas diffusion space 43 is not limited to being partitioned concentrically, and these partitioned regions Z1 to Z3 may be partitioned concentrically into ellipses or rectangles.

[0021] <Pressure sensor> In the gas showerhead 4 of this example having the above-described configuration, each of the compartmentalized regions Z1 to Z3 is provided with a pressure sensor 8. This example is characterized by the use of a small pressure sensor 8 that measures pressure inside the compartmentalized regions Z1 to Z3, which are the gas diffusion spaces 43. This differs from conventional pressure measurement methods in which a pressure gauge provided outside the gas showerhead 4 is connected to each of the compartmentalized regions Z1 to Z3 via a connection port.

[0022] 2 and 3 show examples in which the pressure sensors 8 are provided on the wall surfaces of the partition walls 46 and annular protrusions 44 that form the partitioned areas Z1 to Z3. Alternatively, the pressure sensors 8 may be provided on the bottom surface of the top plate member 41 that forms the ceiling surface of the partitioned areas Z1 to Z3. 3, in the gas showerhead 4 of this example, one pressure sensor 8 is provided in the central circular first compartment Z1. In addition, pressure sensors 8 are provided in the surrounding second and third annular compartments Z2 and Z3, respectively, at positions where lines extending in all directions from the center of each annulus intersect with the partition wall 46 and the annular protrusion 44. That is, four pressure sensors 8 are provided in each of the second and third compartments Z2 and Z3.

[0023] There are no particular limitations on the configuration of the pressure sensor 8, as long as it can be placed within the partitioned regions Z1 to Z3. Examples of pressure sensors 8 that can be placed within the partitioned regions Z1 to Z3 include a Pirani gauge 8a or a diaphragm-type MEMS (Micro Electro Mechanical Systems) pressure sensor (hereinafter also referred to as "MEMS sensor") 8b.

[0024] As shown in the schematic diagram of FIG. 4, the Pirani gauge 8a has a configuration in which a platinum filament 812 is stretched along the axial direction of a cylindrical casing 813 having an opening 814 formed at the tip. The platinum filament 812 is held by a holding member 811 made of a conductive metal. In the Pirani gauge 8a, power is supplied to the platinum filament 812, and a change in temperature of the platinum filament 812 due to collisions of gas molecules is detected as a change in resistance value. Therefore, the Pirani gauge 8a can detect the pressure within the compartment regions Z1 to Z3, which corresponds to the frequency of collisions of gas molecules, as the resistance value of the platinum filament 812.

[0025] Here, if a deposition gas containing halogen atoms, such as the aforementioned Si2Cl6, is supplied as a precursor for the SiO2 film, there is a risk of corrosion of the platinum filament 812. In such a case, the surfaces of the platinum filament 812 and the holding member 811 may be coated with a thin film of an oxide such as yttria (YO3), as long as a decrease in sensitivity is acceptable.

[0026] In the Pirani gauge 8a of this example, a circuit section 816 is provided at the base end of the casing 813. The circuit section 816 includes a small battery that supplies power to the platinum filament 812, a circuit for detecting the resistance value of the platinum filament 812, and a transmission circuit that outputs the detected resistance value as a pressure signal via wireless communication. Note that outputting the pressure signal via wireless communication is not an essential configuration, and a configuration in which the pressure signal is output via a signal line may also be employed. Furthermore, if power is supplied via a power supply line from a power source provided outside the gas diffusion space 43 or if power is supplied via contactless power transmission, the battery can be omitted.

[0027] In the Pirani gauge 8a, the temperature of the platinum filament 812 rises as current is applied, so care must be taken when using highly reactive deposition gases. However, because the compartmentalized regions Z1 to Z3 are maintained at a vacuum atmosphere of several Pa to several hundred Pa, there is little risk of the placement of the Pirani gauge 8a causing a rapid reaction of the deposition gas. On the other hand, when a highly reactive deposition gas that requires careful handling is used, the pressure may be measured using a diaphragm-type MEMS sensor 8b shown in FIG.

[0028] 5 has a configuration in which a diaphragm portion 822 made of silicone rubber is provided on the upper surface of a base portion 821 made of, for example, glass, with a diaphragm membrane 823 disposed via a cavity portion 824. A strain gauge 825 is disposed on the diaphragm membrane 823. For example, the strain gauge 825 is formed of a piezoresistance element whose resistance changes with deformation. With this configuration, when the diaphragm membrane 823 deforms in response to a change in the ambient pressure, the strain gauge 825 also deforms, which can be detected as a change in resistance value. In the MEMS sensor 8b of this example, the surfaces of the diaphragm portion 822 and the strain gauge 825 may also be coated with a thin film of oxide such as Y2O3 to protect them from corrosive film-forming gas, provided that a decrease in sensitivity is acceptable.

[0029] A circuit unit 827 is connected to the strain gauge 825 via a conductive wire 826. The circuit unit 827 includes a small battery that supplies power to the strain gauge 825, a circuit for detecting the resistance value of the strain gauge 825, and a transmitting circuit that outputs the detected resistance value as a pressure signal via wireless communication. In the MEMS sensor 8b of this example, outputting a pressure signal via wireless communication is not an essential configuration, and a configuration in which a pressure signal is output via a signal line may also be adopted. Furthermore, with regard to the power supply method, power may be supplied via a power supply line from a power source provided outside the gas diffusion space 43, or power may be supplied via contactless power transmission. In these cases, the placement of a battery in the circuit unit 827 can be omitted.

[0030] To generate plasma, as described below, high-frequency power may be applied to the gas showerhead 4. In such a case, the Pirani gauge 8a and the circuit sections 816 and 827 of the MEMS sensor 8b may be shielded from the high-frequency power applied to the gas showerhead 4 via an electromagnetic shield. Alternatively, pressure may be measured and a pressure signal may be output via wireless communication when the high-frequency power for plasma generation is not being applied. In addition, a heater for heating the film formation gas may be provided in the gas showerhead 4. In this case, the pressure sensor 8 (Pirani gauge 8a or MEMS sensor 8b) may be configured to be installed on the annular protrusion 44 or the partition wall 46 via a heat insulating member.

[0031] <Gas supply section> The gas shower head 4 is provided with a source gas supply unit 50 for supplying a source gas and a reaction gas supply unit 60 for supplying O2 gas as a reaction gas. The source gas supply unit 50 and the reaction gas supply unit 60 constitute the gas supply unit 7 of this example. The source gas and the reactive gas can be supplied independently to each of the partitioned regions Z1 to Z3 from the source gas supply unit 50 and the reactive gas supply unit 60. In this example, deposition gas supply paths 51, 52, and 53 for supplying the source gas and the reactive gas to each of the partitioned regions Z1 to Z3 are formed in the top plate member 41 of the gas shower head 4. Furthermore, purge gas supply paths 61, 62, and 63 for supplying purge gas for purging each of the partitioned regions Z1 to Z3 are formed in the top plate member 41.

[0032] 1 and 2 are merely examples. In practice, the first to third partitioned regions Z1 to Z3 are provided with an appropriate number of film formation gas supply paths 51, 52, 53 and purge gas supply paths 61, 62, 63. In FIG. 3, the positions of the film formation gas supply paths 51, 52, 53 and purge gas supply paths 61, 62, 63 are indicated by dashed lines. These deposition gas supply paths 51, 52, and 53 are supplied with a source gas (precursor gas) and a carrier gas, and a reactive gas (O 2 gas) and a carrier gas, respectively, via a gas supply unit 7.

[0033] 2, the gas supply unit 7 includes supply paths for source gas, reactive gas, and carrier gas, valves, a flow rate adjustment mechanism, etc. The flow rate adjustment mechanism is constituted by, for example, a mass flow controller. That is, the film formation gas supply paths 51, 52, and 53 are connected to a supply source 54 of a source gas (denoted as "PE (Precursor of Example)" in FIGS. 1 and 2) via source gas supply paths 541, 542, and 543, respectively. The source gas supply paths 541, 542, and 543 are provided with valves V11, V12, and V13 for supplying and stopping the source gas, respectively, and flow rate adjustment mechanisms M11, M12, and M13. The film formation gas supply paths 51, 52, and 53 are also connected to a supply source 55 of Ar gas, which is supplied as a carrier gas, via the source gas supply paths 541, 542, and 543, respectively, and a carrier gas supply path 551. The carrier gas supply path 551 is provided with valves V21, V22, and V23 for supplying and stopping the carrier gas, respectively, and flow rate adjustment mechanisms M21, M22, and M23. The gas used as the carrier gas is not limited to Ar gas, but may be selected from gas species such as Ar, He, Ne, Kr, Xe, and N2, either singly or in combination.

[0034] In addition, the film formation gas supply paths 51, 52, and 53 are connected to a reactive gas (O2 gas) supply source 56 via reactive gas supply paths 561, 562, and 563, respectively. The reactive gas supply paths 561, 562, and 563 are provided with valves V31, V32, and V33 for supplying and stopping the reactive gas, and flow rate adjustment mechanisms M31, M32, and M33, respectively. The film formation gas supply paths 51, 52, and 53 are also connected to a supply source 55 of Ar gas, which is supplied as a carrier gas, via the reactive gas supply paths 561, 562, and 563, respectively, and a carrier gas supply path 552. The carrier gas supply path 552 is provided with valves V41, V42, and V43 for supplying and stopping the carrier gas, and flow rate adjustment mechanisms M41, M42, and M43, respectively.

[0035] In this example, a raw material gas supply unit 50 is configured with the film formation gas supply paths 51, 52, and 53, raw material gas supply paths 541, 542, and 543, valves V11, V12, and V13, flow rate adjustment mechanisms M11, M12, and M13, and a raw material gas supply source 54. A reactive gas supply unit 60 is configured with the film formation gas supply paths 51, 52, and 53, reactive gas supply paths 561, 562, and 563, valves V31, V32, and V33, flow rate adjustment mechanisms M31, M32, and M33, and a reactive gas supply source 56.

[0036] The purge gas supply paths 61, 62, and 63 merge with an Ar gas supply path 553 along the way, and are connected to an Ar gas supply source 55, which is supplied as a purge gas, via a valve V5 and a mass flow controller M5. The operation of each valve and flow rate control mechanism is controlled by a control unit 10, which will be described later.

[0037] In the gas supply unit 7 having the above-described configuration, the valves V11, V12, and V13 for supplying raw material gases are opened when supplying raw material gases to the wafer W. The valves V31, V32, and V33 for supplying reactive gases are opened when supplying reactive gases to the wafer W. The valves V21, V22, and V23 or valves V41, V42, and V43 for supplying Ar gas are opened when supplying carrier gas to the wafer W.

[0038] By this operation, the source gas or reaction gas diluted with a predetermined amount of carrier gas is supplied to the first to third partitioned regions Z1 to Z3 of the gas diffusion space 43 via the source gas supply paths 541 to 543 and the film forming gas supply paths 51 to 53. Then, the source gas or reaction gas is discharged into the processing space 40 from the gas discharge holes 45 formed in the partitioned regions Z1 to Z3 of the shower plate 42, respectively.

[0039] The source gas or reaction gas discharged from the partitioned regions Z1 to Z3 is mainly supplied to the adsorption regions of the wafer W located opposite the partitioned regions Z1 to Z3 of the shower plate 42. That is, a plurality of adsorption regions are formed concentrically along the radial direction in regions opposite the partitioned regions Z1 to Z3 within the surface of the wafer W.

[0040] Therefore, by varying the discharge flow rate of the source gas per unit area among the first to third partitioned regions Z1 to Z3 on the gas shower head 4 side, the flow rate (supply flow rate) of the source gas supplied per unit area can be changed among the three adsorption regions on the wafer W. Furthermore, by varying the discharge time of the source gas among the first to third partitioned regions Z1 to Z3 on the gas shower head 4 side, the supply time of the source gas can be changed among the three adsorption regions on the wafer W side.

[0041] <Processing space and plasma formation mechanism> 1, the explanation will be continued. The space surrounded by the lower surface of the shower plate 42, the annular protrusion 44, and the upper surface of the mounting table 31 forms a processing space 40 in which the above-described film formation is performed. The shower plate 42 is paired with an electrode plate (not shown) in the mounting table 31, and is configured as an electrode plate for forming capacitively coupled plasma (CCP) in the processing space 40.

[0042] A high-frequency power supply 47 is connected to the shower plate 42 via a matching box (not shown). The above-mentioned CCP is formed by supplying high-frequency power from the high-frequency power supply 47 to the gas supplied to the processing space 40 via the shower plate 42. Note that a high-frequency power supply or a DC power supply for applying bias power to the electrode plate may be provided between the electrode plate of the mounting table 31 and the grounded end. Alternatively, the high-frequency power supply 47 may be connected to the electrode plate on the mounting table 31 side instead of the shower plate 42, and the shower plate 42 may be grounded. When film formation is performed without using plasma, the plasma generating mechanism such as the high frequency power supply 47 and bias power supply can be omitted.

[0043] <Control unit> The film forming apparatus 1 is also provided with a control unit 10 consisting of a computer. The control unit 10 includes a program, a memory, a data processing unit consisting of a CPU, and the like. The program contains instructions (steps) for sending control signals from the control unit 10 to each unit of the film forming apparatus 1 and executing film formation, which will be described later. Specifically, the above program controls the timing for opening and closing each valve, the flow rate setting value of the flow rate adjustment mechanism, the timing for turning on and off the high-frequency power supply 47, the heating temperature of the wafer W by the heater, and the like. These programs are stored in a storage unit 101, which may include, for example, a compact disk, a hard disk, an MO (magneto-optical disk), or a non-volatile memory, and installed in the control unit 10.

[0044] 6 is a block diagram showing the electrical configuration for controlling the pressure in the partitioned regions Z1 to Z3 using the pressure sensor 8. In FIG. 6, the gas showerhead 4 is shown partially cut out in a sector shape. For ease of illustration, the film formation gas supply paths 51, 52, and 53 and the purge gas supply paths 61, 62, and 63 formed in the top plate member 41 of the gas showerhead 4 are labeled with reference numerals that identify the respective gas supply paths.

[0045] The control unit 10 reads out, as parameters, the flow rate setting values ​​and supply times of each source gas, reactive gas, carrier gas, and purge gas set in the recipe stored in the memory unit 101. Then, the parameter setting unit 102 sets these parameters for each flow rate adjustment unit (flow rate adjustment mechanism M and opening / closing mechanism of valve V) in the gas supply unit 7.

[0046] The control unit 10 can also acquire pressure signals output from the pressure sensors 8 in the partitioned regions Z1 to Z3 via the receiving unit 80. It then compares each pressure signal with a preset pressure range at the measurement position and corrects the flow rate setting and supply time of each gas based on the comparison results. From this perspective, the control unit 10 can be said to have a function of outputting control signals for adjusting the flow rate of each process gas to each flow rate adjustment unit (flow rate adjustment mechanisms M11 to M13, M21 to M23, M31 to M33, M41 to M43, M5 and opening / closing mechanisms of valves V11 to V13, V21 to V23, V31 to V33, V41 to V43, V5) based on the pressure measurements acquired from the pressure sensors 8.

[0047] <Film formation operation> Next, an example of a substrate processing method according to the present disclosure, which is carried out using the above-described film formation apparatus 1, will be described with reference to Fig. 7. The horizontal axis of each chart shown in Fig. 7 indicates the passage of time within one cycle, and the vertical axis indicates the flow rate setting value of each flow rate adjustment mechanism (M11-M13, M31-M33, M21-M23, M41-M43, M5) expressed in 100% range. However, the flow rate setting values ​​of the flow rate adjustment mechanisms M21-M23, M41-M43, and M5 all show an example in which Ar gas is continuously supplied, so they are shown together in one chart.

[0048] When a wafer W to be processed is transferred from an external vacuum transfer chamber, gate valve 13 is opened, and a transfer mechanism (not shown) holding the wafer W is introduced into processing vessel 11 through load / unload port 12. Then, support pins 38 are raised to receive the wafer W above table 31 waiting at the transfer position. Thereafter, the transfer mechanism is withdrawn from processing vessel 11, and support pins 38 are lowered to place wafer W on table 31 (substrate placing step).

[0049] Next, the gate valve 13 is closed, and the mounting table 31 is raised to the processing position. Furthermore, the pressure inside the processing chamber 11 and the temperature of the wafer W are adjusted. As shown in Fig. 7, Ar gas is continuously supplied to each of the partitioned regions Z1 to Z3 as a purge gas, and the pressure inside the processing chamber 11 can be adjusted by adjusting the exhaust rate.

[0050] Next, film formation on the wafer W begins by the ALD method. The film formation sequence by the ALD method will be described with reference to the chart in Fig. 7. The chart in Fig. 7 shows the timing of supply / stop of various gases into the processing vessel 11 (i.e., supply time) and flow rate setting values ​​in each of the partitioned regions Z1 to Z3.

[0051] In the ALD method, film formation is performed by repeating the following cycle multiple times: supply of source gas → exhaust of source gas with purge gas → supply of reactive gas and plasma formation → exhaust of reactive gas with purge gas. Figure 7 shows the film formation sequence for one cycle.

[0052] In the gas supply unit 7, valves V21 to V23 and V41 to V43 are opened, and Ar gas is continuously supplied from the supply source 55 to the processing space 40 via the gas shower head 4. Valve V5 is also opened, and Ar gas is continuously supplied via each of the purge gas supply paths 61, 62, and 63. Next, valves V11 to V13 are opened, and a source gas is supplied from the supply source 54. The source gas flows into each of the partitioned regions Z1 to Z3 with Ar gas as a carrier gas, and is then discharged into the processing space 40 via the gas discharge holes 45 of the shower plate 42. In this manner, the source gas is supplied to the wafer W, and a precursor is adsorbed onto the surface of the wafer W (step S11).

[0053] In the gas shower head 4, the gas diffusion space 43 is divided into first to third partitioned regions Z1 to Z3, and the gas supply unit 7 is provided with flow rate adjustment mechanisms M11, M12, and M13 that adjust the supply rate of the source gas to each of the partitioned regions Z1 to Z3. With this configuration, the supply time and supply flow rate of the source gas to the wafer W can be made different among the partitioned regions Z1 to Z3. Figure 7 shows an example in which the supply start timing and supply flow rate of the source gas are made different among the partitioned regions Z1 to Z3.

[0054] These flow rate adjustments make it possible to independently adjust the amount of source gas adsorbed in the multiple adsorption regions formed according to the partitioned regions Z1 to Z3. Note that switching between supplying and stopping the source gas also involves flow rate adjustment between a state where the supply flow rate is greater than zero (supply) and a state where the supply flow rate is zero (stop).

[0055] Next, valves V11 to V13 are closed to stop the supply of source gas to wafer W. Meanwhile, valves V21 to V23, V41 to V43, and V5 remain open while Ar gas continues to be supplied, thereby purging source gas remaining in processing space 40 and not adsorbed to wafer W with Ar gas (step S12). In this way, source gas supply unit 50 supplies a mixed gas of Ar gas, which is a carrier gas, and source gas during the supply period of source gas, and continues to supply Ar gas during the period when the supply of source gas is stopped. This prevents backflow of source gas or reactive gas into film formation gas supply paths 51 to 53, source gas supply paths 541 to 543, and reactive gas supply paths 561 to 563.

[0056] Next, valves V31 to V33 are opened, and a reactive gas is supplied from the reactive gas supply source 56. The reactive gas flows into each of the partitioned regions Z1 to Z3 together with Ar gas, which serves as a carrier gas, and is then discharged into the processing space 40 through the gas discharge holes 45 of the shower plate 42. During the supply of O gas, which serves as the reactive gas, high-frequency power is applied to the shower plate 42 from the high-frequency power supply 47, converting the O gas into plasma. This plasma oxidizes the precursor adsorbed on the wafer W, and a layer of SiO is formed as a reaction product (step S13).

[0057] Flow rate adjusting mechanisms M31, M32, and M33 are provided to adjust the amount of reactive gas supplied to each of the partitioned regions Z1 to Z3 even during the reactive gas supply period. This configuration allows the supply time and supply flow rate of the reactive gas to the wafer W to be different among the partitioned regions Z1 to Z3. Figure 7 shows an example in which the supply start timing and supply flow rate of the reactive gas are different among the partitioned regions Z1 to Z3. By adjusting these flow rates, the flow rates of the reactant gas supplied to the plurality of adsorption regions formed according to the partitioned regions Z1 to Z3 can be adjusted independently.

[0058] Thereafter, the application of high-frequency power to the shower plate 42 is stopped, and valves V31-V33 are closed to stop the generation of plasma in the processing space 40 and the supply of reactive gas. Meanwhile, valves V21-V23, V41-V43, and V5 are left open while the supply of Ar gas continues, thereby purging the reactive gas and activated species of plasma remaining in the processing space 40 with Ar gas (step S14). In this way, the reactive gas supply unit 60 supplies a mixture of Ar gas, which serves as a carrier gas, and a reactive gas during the reactive gas supply period, and continues to supply Ar gas during the reactive gas supply period. This prevents the precursor and reactive gas from flowing back into the film formation gas supply paths 51-53, the source gas supply paths 541-543, and the reactive gas supply paths 561-563.

[0059] By repeating the above-described film formation sequence a preset number of times, a film (in this example, a SiO2 film) of a desired thickness can be formed on the surface of the wafer W (a step of supplying the processing gas into the processing vessel 11). In addition, by independently adjusting the supply times and supply flow rates of the source gas and the reactive gas among the multiple partitioned regions Z1 to Z3, the thickness distribution of the film formed on the wafer W can also be adjusted.

[0060] In the example described above, the gas supply unit 7 can be used to control the flow rate setting values ​​of the flow rate adjustment mechanisms M11, M12, M13, M31, M32, and M33 provided upstream of each of the partitioned regions Z1 to Z3, and the supply times of the raw material gas and the reactive gas.

[0061] At this time, it can be confirmed by prior experiments, fluid simulations, etc. that the supply flow rates of the film formation gas and purge gas necessary to obtain a desired film thickness distribution from each of the partitioned regions Z1 to Z3 to each adsorption region on the wafer W side are secured. However, in actual operation of the film formation apparatus 1, it may be necessary to adjust other parameters that affect the gas supply flow rates, such as adjusting the pressure inside the processing chamber 11, as necessary. At this time, it is not realistic to predict all possible changes in these other parameters and comprehensively identify the flow rate setting values ​​and supply times of each gas in the gas supply unit 7 by prior experiments and simulations.

[0062] Furthermore, in film formation using the ALD method developed by the applicant, it may be necessary to switch between steps S11 to S14 shown in FIG. 7 at intervals of, for example, 1 second or less, or, under more stringent conditions, about 0.2 to 0.5 seconds. When switching is performed at such extremely short intervals, the next step begins before the gas flow in each step reaches a steady state. In such an unsteady state, it may be difficult to accurately determine the flow rate through prior experiments or simulations.

[0063] 1 to 6, the film forming apparatus 1 of this embodiment is equipped with compact pressure sensors 8 that measure the pressure inside each of the divided regions Z1 to Z3. These pressure sensors 8 measure the pressure inside each of the divided regions Z1 to Z3 and output a pressure signal corresponding to the pressure measurement value (a step of outputting a pressure signal). For example, based on the results of this pressure measurement, the control unit 10 can determine, through operations based on the flow rate setting value and supply time set for the gas supply unit 7, whether the pressure inside each of the divided regions Z1 to Z3 is within the pressure range assumed for setting these parameters.

[0064] If the pressure in the partitioned regions Z1 to Z3 is outside the preset pressure range, it can be determined that the supply flow rate of the gas being supplied to the adsorption region on the wafer W side at that time is different from the supply flow rate assumed when the parameters were set. Therefore, the control unit 10 corrects the flow rate setting value and supply time for the parameters related to the gas supply that are out of the pressure range via the parameter setting unit 102 (a process of adjusting the flow rate of the process gas). This correction allows the actual gas flow rate supplied to the adsorption region on the wafer W to approach the supply flow rate required to obtain the desired film thickness distribution.

[0065] To cite a specific example based on the example of FIG. 7 , assume that during step S11, the pressure measured by the pressure sensor 8 installed in the second partitioned region Z2 is higher than the preset pressure range. In this case, the timing for starting the supply of the source gas may be delayed during the next cycle or during processing of the next wafer W, thereby shortening the time for supplying the source gas. Furthermore, when performing real-time control in which control is completed within step S11 in which the pressure measurement is performed, the timing for stopping the supply of the source gas may be advanced to shorten the time for supplying the source gas. Alternatively, the flow rate setting of the flow rate adjustment mechanism M12 for the source gas supplied toward the second partitioned region Z2 may be lowered to reduce the supply flow rate of the source gas. The flow rate setting of the flow rate adjustment mechanism M12 may be adjusted during processing of the next cycle or the next wafer W, or the flow rate setting may be changed while measuring the pressure in step S11.

[0066] As another example, suppose that the pressure measured by the pressure sensor 8 provided in the third partitioned region Z3 during step S12 is lower than a preset pressure range. In this case, the supply flow rate of Ar gas supplied as a carrier gas to the third partitioned region Z3 may be increased during step S12 in the next cycle or when processing the next wafer W, to supplement the supply amount of purge gas. Alternatively, the set flow rate of Ar gas may be increased while measuring the pressure in step S12. In this way, by measuring the pressure in the partitioned regions Z1 to Z3 using the pressure sensor 8, it is possible to more accurately control the supply of the film forming gas and the purge gas.

[0067] After repeating the above steps S11 to S14 a preset number of times, the mounting table 31 is lowered, and the wafer W is unloaded from the processing chamber 11 in the reverse order of the loading procedure, thereby completing the film formation on the wafer W. The film formation apparatus 1 according to the embodiment described above has the following advantages. The pressures in the compartmentalized regions Z1 to Z3 of the gas shower head 4 can be measured quickly. That is, the gas shower head 4 has sensing portions of the pressure sensors 8 (the platinum filaments 812 of the Pirani gauge 8a, the diaphragm membrane 823 and the strain gauge 825 of the MEMS sensor 8b) provided inside the compartmentalized regions Z1 to Z3. This configuration enables the pressures in the compartmentalized regions Z1 to Z3 to be measured more directly and accurately, enabling accurate and quick pressure measurements.

[0068] One possible method for measuring the pressures in the compartments Z1 to Z3 is to connect a pressure gauge located outside the gas showerhead 4 to the compartments Z1 to Z3 via a connection port. However, as mentioned above, when the gases supplied to the compartments Z1 to Z3 are switched one after another within a short time period of one second or less, the response of an external pressure gauge connected via a connection port becomes slow. As a result, it may be difficult to obtain a resolution in the pressure measurements that allows for identifying pressure changes in steps S11 to S14.

[0069] In this regard, the pressure sensors 8 provided in the gas diffusion spaces 43 corresponding to the partitioned regions Z1 to Z3 directly measure the pressures in the partitioned regions Z1 to Z3 without using connection ports, and can therefore measure the pressures quickly and accurately. As a result, this can be used for more accurate gas supply control, even when gases are switched quickly during film formation by the ALD method.

[0070] <Variations> 1 to 3, a configuration has been described in which multiple gas diffusion spaces 43 (first to third partitioned regions Z1 to Z3) are provided, and one or more pressure sensors 8 are provided in each of these partitioned regions Z1 to Z3. In this case, it is not essential to provide one or more pressure sensors 8 in all of the multiple gas diffusion spaces 43. If necessary, one or more pressure sensors 8 may be provided in some of the multiple gas diffusion spaces 43.

[0071] The number of gas diffusion spaces 43 provided in the film formation apparatus 1 (gas shower head 4) is not limited to plural. For example, one or more pressure sensors 8 may be disposed in only one gas diffusion space 43 formed for the gas shower head 4, and the supply of film formation gas and purge gas may be controlled based on the results of pressure measurements.

[0072] Furthermore, the method by which the control unit 10 adjusts the flow rates of the film formation gas and purge gas based on the results of the pressure measurement value in the gas diffusion space 43 acquired from the pressure sensor 8 is not limited to correcting the parameters (flow rate setting value, supply time) using the parameter setting unit 102. For example, a flow rate adjustment valve may be provided on the side of the Ar gas supply path 553, and the flow rate of the Ar gas may be continuously adjusted so that the pressure in the partitioned regions Z1 to Z3 is maintained within a preset pressure range.

[0073] Additionally, the method of forming a film using the film forming apparatus 1 is not limited to the ALD method described with reference to Fig. 7. For example, a pressure sensor 8 may be provided in the gas diffusion space 43 of the film forming apparatus 1 that forms a film by a CVD method by continuously supplying a source gas alone or continuously supplying a source gas and a reactive gas in parallel.

[0074] The gas shower head 4 having the pressure sensor 8 provided in the gas diffusion space 43 is not limited to being applied to the film formation apparatus 1 that forms a film on the wafer W. The pressure sensor 8 may be provided in the gas shower head 4 that supplies gas into the processing chamber 11 of an etching processing apparatus that supplies an etching gas to the wafer W to etch a film formed on the wafer W, or a modifying apparatus that performs a modifying process that modifies a substance on the wafer W with a modifying gas. In these cases, the etching gas and the modifying gas each correspond to the processing gas in the present disclosure.

[0075] In particular, etching equipment includes an ALE (Atomic Layer Etching) equipment that performs ALE, which etches the atomic layers of a target film one by one. The ALE equipment supplies a modifying gas that acts only on the outermost atomic layer of the wafer, and alternates between a chemical modification process and an etching process that removes only the chemically modified portion. The supply of modifying gas and etching gas in ALE requires high-precision flow rate control in a short time, similar to film formation using the ALD method. Therefore, one particularly preferred embodiment is a configuration in which a pressure sensor 8 is installed in a gas showerhead 4 that supplies these modifying gas and etching gas as process gases to measure the pressure, and the supply flow rate is adjusted based on the measurement results.

[0076] Furthermore, the technique of providing a pressure sensor 8 in the gas diffusion space 43 can also be utilized during other times besides processing the wafer W. For example, when developing the gas showerhead 4, the pressure sensor 8 may be provided in the gas diffusion space 43 to measure the pressure in the gas diffusion space 43 as basic data. When performing case studies on the volume of the gas diffusion space 43 or the number and arrangement of the gas outlet holes 45 formed in the shower plate 42, the pressure measured in the gas diffusion space 43 can be used to accurately grasp the current situation.

[0077] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0078] W wafer 1 Film deposition equipment 10 Control Unit 11 Processing container 31 Mounting table 4 gas shower heads 43 Gas diffusion space 7. Supply control equipment 8. Pressure Sensor

Claims

1. An apparatus for processing a substrate by supplying a processing gas to a substrate in a processing chamber, a mounting table provided in the processing chamber for mounting the substrate thereon; a gas shower head provided at a position facing the mounting table, the gas shower head including: a gas diffusion space for diffusing the processing gas; and a shower plate having a plurality of gas supply holes formed therein for supplying the processing gas diffused in the gas diffusion space into the processing vessel; a gas supply unit provided for supplying the processing gas to the gas diffusion space and including a flow rate regulator for the processing gas; a pressure sensor unit that is provided in the gas diffusion space and outputs a pressure signal corresponding to a pressure measurement value in the gas diffusion space; a control unit that outputs a control signal to the flow rate regulator to regulate the flow rate of the processing gas based on the pressure measurement value acquired from the pressure sensor unit via the pressure signal, the gas showerhead includes a plurality of the gas diffusion spaces separated from each other by partition walls; the pressure sensor units are provided directly within the plurality of diffusion spaces, The apparatus is configured such that the plurality of gas supply holes are provided in each of the plurality of diffusion spaces, so that the process gas is supplied into the process vessel from these diffusion spaces independently of one another.

2. The gas supply unit includes a plurality of flow rate adjusting units that adjust the flow rate of the processing gas supplied to the plurality of gas diffusion spaces, respectively; 2. The apparatus according to claim 1, wherein the control unit outputs the control signal to a flow rate control unit that controls the flow rate of the processing gas supplied to the gas diffusion space in which each of the pressure sensors is provided, based on the pressure measurement values ​​obtained from the plurality of pressure sensor units.

3. The apparatus according to claim 1 , wherein the gas supply unit supplies, as the processing gas, a film-forming gas for forming a film on the substrate.

4. 4. The apparatus according to claim 3, wherein the gas supply unit repeatedly switches between supplying a source gas containing a source material of the film to be formed on the substrate and a reaction gas for reacting with the source material to obtain the film, and further, upon the switching, supplies a purge gas for purging the gas diffusion space after stopping the supply of the source gas or the reaction gas, respectively.

5. 5. The device according to claim 1, wherein the pressure sensor unit has a wireless communication function and outputs the pressure signal via wireless communication.

6. 1. A gas showerhead for supplying a process gas to a substrate undergoing substrate processing, comprising: a gas diffusion space for diffusing the processing gas supplied from the outside, and a shower plate having a plurality of gas supply holes formed therein for supplying the processing gas diffused into the gas diffusion space; a pressure sensor unit provided in the gas diffusion space and outputting a pressure signal corresponding to a pressure measurement value in the gas diffusion space; the gas showerhead includes a plurality of the gas diffusion spaces separated from each other by partition walls; the pressure sensor units are provided directly within the plurality of diffusion spaces, a plurality of gas supply holes are provided in each of the plurality of diffusion spaces, so that the diffusion spaces are configured to supply the processing gas into a processing vessel accommodating the substrate independently of one another.

7. 7. The gas showerhead according to claim 6, wherein the pressure sensor unit is configured by a Pirani gauge or a diaphragm-type MEMS (Micro Electro Mechanical Systems) pressure sensor.

8. 8. The gas showerhead according to claim 6, wherein the pressure sensor unit has a wireless communication function and outputs the pressure signal via wireless communication.

9. A method for processing a substrate by supplying a processing gas to a substrate in a processing chamber, comprising: carrying the substrate into the processing vessel and placing the substrate on a mounting table provided in the processing vessel; supplying the processing gas into the gas diffusion space using a gas shower head provided at a position opposite the mounting table and having a gas diffusion space and a shower plate formed with a plurality of gas supply holes, and supplying the processing gas diffused into the gas diffusion space into the processing chamber via the shower plate; a step of outputting a pressure signal corresponding to a pressure measurement value in the gas diffusion space by a pressure sensor unit provided in the gas diffusion space; adjusting a flow rate of the processing gas supplied to the gas diffusion space based on the pressure measurement value acquired from the pressure sensor unit via the pressure signal; the gas showerhead includes a plurality of the gas diffusion spaces separated from each other by partition walls; the pressure sensor units are provided directly within the plurality of diffusion spaces, In the step of supplying the processing gas into the processing vessel, the plurality of gas supply holes are provided in each of the plurality of diffusion spaces, so that the processing gas is supplied into the processing vessel from these diffusion spaces independently of each other.

10. A method as described in Claim 9, wherein in the process of adjusting the flow rate of the processing gas, the flow rate of the processing gas supplied to the gas diffusion space in which each pressure sensor is installed is adjusted based on the pressure measurement values ​​obtained from the multiple pressure sensor units.

11. The method according to claim 9 or 10, wherein the processing gas is a deposition gas for depositing a film on the substrate.

12. 12. The method according to claim 11, wherein in the process of supplying the processing gas, a source gas containing raw materials for the film to be formed on the substrate and a reaction gas for reacting with the raw materials to obtain the film are repeatedly supplied as the film forming gas by switching between them, and further, during the switching, after stopping the supply of the source gas or the reaction gas, a purge gas is supplied to purge the gas diffusion space.

13. The method according to claim 9 , wherein the pressure sensor unit has a wireless communication function, and the step of outputting the pressure signal by wireless communication is carried out.

Images