Substrate processing method, substrate processing apparatus, and software

Abstract

The etching method according to the present disclosure includes: supplying a first etching gas and a second etching gas including at least one of ammonia gas and amine gas from a gas supply source to a gas supply path; a storage step of storing the first etching gas and the second etching gas in a storage part provided in the gas supply path and increasing the pressure inside the storage part; and a gas supply step of opening a valve provided on the downstream side of the reservoir in the gas supply path to supply the first etching gas and the second etching gas stored in the reservoir to a processing container in which a substrate is stored so as to etch a first film formed on the substrate.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method, a substrate processing device, and software. Background Art

[0002] When processing substrates such as semiconductor wafers (hereinafter referred to as wafers), gases temporarily stored in a tank are sometimes released into a processing vessel for processing. Patent Document 1 describes the use of He, HCl, and SF6 gases stored in a tank to perform etching on substrates used in the manufacture of flat panel displays (FPDs).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5235293 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a technology that enables highly uniform etching of various portions within a surface of a substrate when etching the substrate using a first etching gas and a second etching gas containing at least one of ammonia gas and amine gas.

[0008] Solutions for solving problems

[0009] The etching method disclosed herein includes the following steps: supplying a first etching gas and a second etching gas including at least one of ammonia gas and amine gas from a gas supply source to a gas supply path;

[0010] a storing step of storing the first etching gas and the second etching gas in a storage portion provided in the gas supply path and increasing the pressure inside the storage portion; and

[0011] In the gas supply process, a valve provided on the downstream side of the storage portion in the gas supply path is opened to supply the first etching gas and the second etching gas stored in the storage portion to a processing container in which a substrate is stored, so as to etch the first film formed on the substrate.

[0012] Effects of the Invention

[0013] The present disclosure enables highly uniform processing of various portions within the surface of the substrate when etching the substrate using a first etching gas and a second etching gas containing at least one of ammonia gas and amine gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1It is a longitudinal sectional front view of an etching apparatus as one embodiment of the present disclosure.

[0015] Figure 2 It is a longitudinal sectional side view of the etching device.

[0016] Figure 3 It is a schematic perspective view showing the interior of the etching device.

[0017] Figure 4 is a timing diagram of the process performed by the etching apparatus.

[0018] Figure 5 1 is a functional diagram showing the operation of the etching device.

[0019] Figure 6 1 is a functional diagram showing the operation of the etching device.

[0020] Figure 7 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0021] Figure 8 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0022] Figure 9 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0023] Figure 10 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0024] Figure 11 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0025] Figure 12 It is a schematic diagram showing a longitudinal cross section of the surface of the wafer to be etched.

[0026] Figure 13 is a timing diagram of other processes performed by the etching apparatus.

[0027] Figure 14 1 is a functional diagram showing the operation of the etching device.

[0028] Figure 15 is a timing diagram of other processes performed by the etching apparatus.

[0029] Figure 16 This is a timing chart for explaining the processing in the evaluation test. DETAILED DESCRIPTION

[0030] Regarding the etching device 1 which is one embodiment of the etching device of the present disclosure and implements the etching method involved in the present disclosure, Figure 1 、 Figure 2 1 and 2 show a longitudinal sectional front view and a longitudinal sectional side view, respectively. First, an overview of the process performed in the etching apparatus 1 will be described. The etching apparatus 1 uses a halogen-containing gas and an alkaline gas as etching gases to etch the surface of the wafer W under a desired pressure in a vacuum atmosphere. During this etching, no plasma is formed around the wafer W.

[0031] The wafer W transported to the etching apparatus 1 has a SiOx (silicon oxide) film 101 formed as a first film and a SiN (silicon nitride) film 102 formed as a second film, with these films exposed on the surface of the wafer W. Both the SiOx film 101 and the SiN film 102 are susceptible to etching by the etching gas. In other words, when a halogen-containing gas as the first etching gas and an alkaline gas as the second etching gas are supplied together, both the SiOx film 101 and the SiN film 102 are etched.

[0032] The etching apparatus 1 is configured to selectively etch the SiOx film 101 between the SiOx film 101 and the SiN film 102 with high uniformity across the surface of the wafer W. Specifically, the etching apparatus 1 utilizes the difference in incubation time with etching gas (halogen-containing gas and alkaline gas) between the SiOx film 101 and the SiN film 102 to perform the aforementioned selective etching. The incubation time refers to the time from when the gas is adsorbed onto the film on the substrate until it begins to react with the film.

[0033] As the halogen-containing gas, a fluorine-containing gas, more specifically, hydrogen fluoride (HF) gas, is used. As the alkaline gas, NH3 (ammonia) gas or amine gas is used. More specifically, trimethylamine (TMA) gas is used. When using these etching gases, the incubation time for the SiOx film 101 is shorter than that for the SiN film 102. That is, immediately after both the halogen-containing gas and the alkaline gas are supplied to the wafer W, the SiOx film 101 is etched, while the SiN film 102 is not.

[0034] The etching apparatus 1 is configured to store the wafer W in the processing container 11 and exhaust the gas therein. Meanwhile, the etching gas is stored in a tank and pressurized. Furthermore, the etching gas is released from the tank into the processing container 11. This allows the etching gas to diffuse rapidly within the processing container 11. Furthermore, the etching gas supply is stopped relatively quickly from the start of supply. By stopping the etching gas supply and exhausting the processing container 11, the etching gas is removed from the processing container 11, thereby suppressing etching of the SiN film 102.

[0035] The supply and shutoff of the etching gas into the processing vessel 11 is controlled by a valve located downstream of the tank. By repeatedly opening and closing this valve at a relatively high rate, the SiOx film 101 is selectively etched to the desired amount. Furthermore, the etching gas released from the tank diffuses rapidly within the processing vessel 11, thereby minimizing variations in the timing of etching gas adsorption across the surface of the wafer W. This results in highly uniform etching across the surface of the wafer W.

[0036] As the above-mentioned tanks, a tank for halogen-containing gas and a tank for alkaline gas are provided separately. In other words, HF gas and NH3 gas or TMA gas are stored in different tanks (tanks 81 and 82). This prevents the halogen-containing gas and alkaline gas from reacting with each other while they are stored in the tanks. In conjunction with the provision of tanks for each gas, the above-mentioned valves are provided as valve V1 on the downstream side of tank 81 and as valve V2 on the downstream side of tank 82.

[0037] In this example, the timing of opening and closing valves V1 and V2 is synchronized. That is, the period during which HF gas is supplied to processing vessel 11 coincides with the period during which NH3 gas or TMA gas is supplied to processing vessel 11. Furthermore, two wafers W are stored in processing vessel 11, and these two wafers W are placed on worktables 5 arranged side by side within processing vessel 11. The aforementioned etching process is performed uniformly and uniformly on these two wafers W. This improves the productivity of the apparatus.

[0038] Next, regarding the schematic structure of the etching device 1 described above, reference will be made to the diagram showing the interior of the device. Figure 3 The processing container 11 constituting the etching apparatus 1 is described with reference to a perspective view. The processing container 11 comprises a lid 12 and a container body 13. The container body 13 forms the side walls and bottom wall of the processing container 11. The container body 13 includes an outer wall portion 14 and an inner wall portion 15, each of which has a concave shape when viewed in longitudinal section. The inner wall portion 15 is located within the outer wall portion 14, thereby forming a double-walled side wall and bottom wall of the processing container 11.

[0039] A processing space-forming member 41 is provided within the inner wall 15. The processing space-forming member 41 is used to divide the area surrounded by the container body 13 into two sections, one for processing wafers W. The processing space-forming member 41 can be raised and lowered freely without interfering with the transfer of wafers W to the worktable 5. The two processing spaces 4 will sometimes be referred to as processing spaces 4A and 4B to distinguish them from each other.

[0040] Two shower plates 3 are installed on the lower surface of the lid 12 of the processing container 11, separated on the left and right sides. Together with a processing space-forming member 41, these shower plates 3 form processing spaces 4A and 4B, and supply gas to these processing spaces 4A and 4B, respectively. Furthermore, a worktable 5 for placing wafers W is installed in each processing space 4A and 4B. Each worktable 5 can be raised or lowered, allowing wafers W to be positioned at a desired height for processing. Furthermore, exhaust from the processing spaces 4A and 4B is provided through exhaust ports 28, which are located at the left and right center openings of the bottom of the container body 13.

[0041] Next, the structure of each part of the etching device 1 is described in detail. In the following description, regarding the shower plate 3, the shower plate 3 forming the processing space 4A and the shower plate 3 forming the processing space 4B are sometimes referred to as 3A and 3B respectively to distinguish them from each other. In addition, regarding the workbench 5, the workbench 5 set in the processing space 4A and the workbench 5 set in the processing space 4B are sometimes referred to as 5A and 5B respectively to distinguish them from each other. In addition, the same components of the components for processing the wafer W in the processing space 4A and the components for processing the wafer W in the processing space 4B are marked with the same numbers to show them. In addition, the left and right directions and the front and back directions are respectively represented as the X direction and the Y direction that are orthogonal to each other in the figure.

[0042] The upper end of the inner wall portion 15, which constitutes the container body 13, extends outward, thereby forming a flange 16. This flange 16 is supported from below by the upper end of the outer wall portion 14. Furthermore, the inner wall portion 15 is removably attachable to and detachable from the outer wall portion 14. A gap 17 is formed between the outer wall portion 14 and the inner wall portion 15. As described later, holes are formed at various locations in the inner wall portion 15 and the outer wall portion 14 to allow the worktable 5 and the processing space-forming member 41 to be raised and lowered within the processing container 11, as well as holes for exhaust. O-rings 37 are provided as sealing members along the edges of each of these holes, and these O-rings 37 are tightly fitted to the outer wall portion 14 and the inner wall portion 15. As a result, the gap 17 is disconnected from these holes, forming a sealed space.

[0043] Inert gas is supplied and exhausted into gap 17 via a gas supply pipe and exhaust pipe (not shown) connected from the outside of processing container 11. During processing of wafers W, gap 17 is maintained at a relatively low pressure. This prevents gas from leaking from processing space 4 to the outside of processing container 11 and effectively insulates processing space 4 from the outside of processing container 11.

[0044] Furthermore, through holes 18 and 19 are formed in the front wall portions of the outer wall portion 14 and the inner wall portion 15 constituting the container body 13, respectively. These through holes 18 and 19 overlap with each other in the front-back direction (Y direction) (see FIG. Figure 2The through holes 18 and 19 are slit-shaped elongated in the left-right direction (X direction), and the cylindrical member 21 is in close contact with the circumference forming the through holes 18 and 19 and is provided to extend from the through hole 18 to the through hole 19 in a manner extending forward and backward.

[0045] The area surrounded by the cylindrical member 21 constitutes a transfer port 22 for wafers W. Wafers W are delivered to the workstations 5A and 5B through the left and right areas of the transfer port 22, respectively. The transfer port 22 is opened and closed by a gate valve 23 provided in front of the outer wall 14. Wafers W are transferred between the interior and exterior of the processing container 11 via the transfer port 22 by a transfer mechanism (not shown).

[0046] Furthermore, the flange 16 of the inner wall portion 15 supports the peripheral edge of the cover 12 via a heater (not shown) formed along the flange 16. Shower plates 3 (3A, 3B) are provided on the lower surface of the cover 12, spaced apart from each other on the left and right sides. The shower plates 3 are circular in plan view and each includes a diffusion space 32 for horizontally diffusing gas and a gas outlet 33 connected to the diffusion space 32. A plurality of gas outlets 33 are dispersedly formed on the lower surface of the shower plate 3, each opening toward the upper surface of the workbench 5.

[0047] A flow path forming portion 34 is provided on the upper side of the lid 12 of the processing container 11. A piping system 6, described later, is connected to the flow path forming portion 34. Gas supplied from the piping system 6 is supplied to the diffusion spaces 32 of the shower plates 3A and 3B via the flow paths formed in the flow path forming portion 34. The circuit for supplying the etching gas in the piping system 6 is shared by the shower plates 3A and 3B. The flow paths in the flow path forming portion 34 are configured to distribute the etching gas supplied from the circuit to the respective diffusion spaces 32 of the shower plates 3A and 3B.

[0048] Two through-holes 24 are formed at intervals on the left and right sides of the bottom of the inner wall portion 15 constituting the container body 13. The portion of the bottom of the outer wall portion 14 that overlaps with the through-holes 24 constitutes the bottom forming portion 10. A lower inner wall 25, which is a cylindrical body, is provided on each bottom forming portion 10. The main body of the lower inner wall 25 is located within the through-hole 24, and the upper end of the lower inner wall 25 extends outward at a position above the through-hole 24, thereby forming a flange 26. In addition, an exhaust path 27 serving as a through-hole is formed on the side wall on the lower side of the lower inner wall 25, and the inside and outside of the lower inner wall 25 are connected via the exhaust path 27.

[0049] Furthermore, an exhaust port 28 is formed at the bottom of the outer wall portion 14, opening in the left-right direction between the positions of the aforementioned through-holes 24. A through-hole 29 is formed above the exhaust port 28 at the bottom of the inner wall portion 15. Exhaust port 28 can exhaust the area surrounded by the inner wall portion 15 through this through-hole 29. One end of an exhaust pipe 20 is connected to the bottom of the outer wall portion 14 from below, opening toward the exhaust port 28. Furthermore, the other end of the exhaust pipe 20 is connected to the exhaust mechanism 2A via a valve V10. The exhaust mechanism 2A is comprised of, for example, a turbomolecular pump or a dry pump, and adjusts the pressure within the processing container 11 by adjusting the opening of the valve V10.

[0050] The processing space-forming member 41 is described in detail. The processing space-forming member 41 extends horizontally and has two vertically spaced through holes 42 formed therein. Each through hole 42 is a hole for forming the processing space 4 and has a circular shape when viewed from above. The upper edge of the processing space-forming member 41 extends outward to form an upper flange 43. Furthermore, an O-ring 38 is provided along the upper edge of each through hole 42.

[0051] Furthermore, the lower end portion of each through-hole 42 protrudes toward the central axis of the through-hole 42, thereby forming a lower flange 44. An O-ring 39 is provided on the lower flange 44 along the circumference of the through-hole 42. The lower flange 44 is located below the flange 26 of the lower inner wall 25. The portion above the lower flange 44 of the circumferential surface forming the through-hole 42 is designated as the inner circumferential surface 45.

[0052] The left and right central lower portions of the processing space forming member 41 are supported by support columns 46. The support columns 46 extend through the bottom of the processing container 11 and are connected to a lifting mechanism 47 disposed outside the processing container 11. Reference numeral 48 in the figure denotes a flange disposed on the support columns 46 on the outside of the processing container 11. Reference numeral 49 in the figure denotes a bellows capable of vertical expansion and contraction. This bellows surrounds the support columns 46 and is connected to the flange 48 and the bottom of the processing container 11, thereby ensuring airtightness within the processing container 11. Furthermore, the positions of the support columns 46 and the lifting mechanism 47 are offset rearward relative to the position where the exhaust port 28 is formed. This lifting mechanism 47 allows the processing space forming member 41 to be raised and lowered between a processing position on the upper side and a standby position on the lower side.

[0053] Figure 1 、 Figure 2The figures show the states where the processing space forming member 41 is located at the processing position and the standby position, respectively. In the processing position, the O-ring 38 on the upper flange 43 is in close contact with the periphery of the shower plate 3, and the O-ring 39 on the lower flange 44 is in close contact with the flange 26 of the lower inner wall 25. Thus, a space surrounded by the shower plate 3, the processing space forming member 41, the lower inner wall 25, and the bottom of the outer wall 14 is formed on the left and right sides of the processing container 11. A workbench 5 is provided in this space, and the area above the workbench 5 in this space is the processing space 4. Each processing space 4 is exhausted through the exhaust port 28 via the exhaust path 27 of the lower inner wall 25 mentioned above. In addition, as shown Figure 2 As shown, the upper end of the processing space forming member 41 at the standby position is located below the transfer port 22 , thereby enabling the wafer W to be transferred into the processing container 11 .

[0054] Furthermore, shafts 40 are provided, extending downward from the left and right sides of the upper flange 43 and penetrating the inner wall 15 and outer wall 14. Shafts 40 prevent the processing space-forming member 41 from shaking during raising and lowering. Similar to the support 46, shafts 40 also have flanges 48 and are surrounded by bellows 49 connected to the flanges 48 and the bottom of the processing container 11, thereby ensuring airtightness within the processing container 11.

[0055] In addition, when the exhaust path in the processing container 11 is formed as described above, a protective film for corrosion protection against the etching gas is formed on the parts of the processing container 11 that come into contact with the etching gas or the parts that may come into contact with the etching gas. Therefore, the protective film is a film made of a material different from the base material constituting the processing container 11. Specifically, for example, the protective film is formed on the side surface of the inner wall portion 15 facing the processing space 4, the bottom surface, and the upper surface of the bottom forming portion 10 constituting the outer wall portion 14. The inner wall portion 15 and the bottom forming portion 10 can be loaded and unloaded relative to other parts constituting the processing container 11, thereby facilitating maintenance of the device. The base material of the processing container 11 is, for example, aluminum, and the material of the protective film can be appropriately selected according to the etching gas used. When HF gas, NH3 gas, or TMA gas is used as in this example, the protective film is made of, for example, Ni (nickel).

[0056] Next, the workbench 5 (5A, 5B) will be described. Each workbench 5 is circular when viewed from above, with its upper surface facing the lower surface of the shower plate 3, and its side surface facing the inner peripheral surface 45 of the through-hole 42 of the processing space forming member 41. The upper side of the workbench 5 is configured as an electrostatic holding disk (holding disk: chuck) that adsorbs the wafer W placed on the upper surface of the workbench 5. A fluid flow path 51 is formed on the lower side of the workbench 5. By supplying a fluid whose temperature has been adjusted by a temperature adjustment mechanism (not shown) to the flow path 51, the wafer W adsorbed on the workbench 5 is brought to the desired temperature. In addition, a supply pipe and an exhaust pipe for the fluid in the flow path 51 are connected to the workbench 5, but are not shown in the figure.

[0057] The upper end of an enclosure 52 that is concave in a longitudinal section is connected to the lower part of each workbench 5, and a horizontal plate 53 is provided in the enclosed space surrounded by the enclosure 52 and the lower surface of the workbench 5. Three (only two are shown in the figure) vertically extending pins 54 are provided on the horizontal plate 53. The horizontal plate 53 is connected to a pillar 55 that passes through the bottom of the enclosure 52 and the bottom forming portion 10 of the processing container 11, and the lower end of the pillar 55 is connected to a lifting mechanism 56 provided on the outside of the processing container 11. The pins 54 for supporting the wafer W protrude and sink on the upper surface of the workbench 5 through the lifting mechanism 56, and the wafer W is transferred between the conveying mechanism (not shown) and the workbench 5. In addition, 50 in the figure is a through hole provided on the workbench 5, through which the pins 54 pass.

[0058] Furthermore, support columns 57, which support the enclosure 52 from below, are provided so as to penetrate the bottom-forming portion 10 of the processing container 11 and are connected to a lifting mechanism 58 disposed outside the processing container 11. A bellows 59, which surrounds the support columns 57 and the aforementioned support columns 55 and is capable of vertical expansion and contraction, is provided so as to be surrounded by the lower inner wall 25. The bellows 59 has an upper end connected to the periphery of the enclosure 52 and a lower end connected to the bottom of the outer wall 14. Similar to the bellows 49, it also ensures airtightness within the processing container 11.

[0059] Furthermore, the support 57, the lifting mechanism 58, and the bellows 59 are provided for each work table 5. Therefore, the heights of the work tables 5A and 5B can be adjusted individually. However, in this example, the heights of the work tables 5 are made uniform so that the wafers W on the work tables 5A and 5B can be processed in the same manner. Furthermore, the fact that the work tables 5 can be raised and lowered in this manner means that the volume of the area above the work tables 5, i.e., the processing space 4, can be adjusted.

[0060] Next, the piping system 6 will be described. The piping system 6 includes piping 61, 62, 63, and 64 whose downstream ends are connected to the flow path forming portion 34. Piping 61 is connected to the shower plate 3A, and piping 62 is connected to the shower plate 3B. Furthermore, the upstream side of piping 61 is connected to the N2 gas supply source 71A via a flow adjustment mechanism 60, and the upstream side of piping 62 is connected to the N2 gas supply source 71B via a flow adjustment mechanism 60. The flow adjustment mechanism 60 is composed of a valve and a mass flow controller, and switches the supply and cutoff of gas to the downstream side of the flow path and adjusts the flow rate of the gas. In addition, the flow adjustment mechanism 60 provided in piping other than piping 61 and 62 described later has the same structure as the flow adjustment mechanism 60 provided in piping 61 and 62. The N2 (nitrogen) gas supplied from the N2 gas supply source 71 acts as a carrier gas for the etching gas and also acts as a purge gas for purging the interior of the processing container 11.

[0061] Pipes 63 and 64 form a gas flow path with a storage unit. The downstream end of pipe 63 is connected to shower plates 3A and 3B via the flow path of flow path forming portion 34. Furthermore, pipe 63 is provided with valve V1, tank 81, and valve V3 in this order toward the upstream side. Furthermore, upstream of valve V3, pipe 63 branches to form pipes 63A and 63B. Pipe 63A is connected to HF gas supply source 72 via flow control mechanism 60. Pipe 63B is connected to N2 gas supply source 73 via flow control mechanism 60. The N2 gas supplied from N2 gas supply source 73 serves as a diluent for the HF gas. Valve V3 is open while the various gases are being supplied to and stored in tank 81, serving as the first storage unit. It is closed while valve V1, serving as the first valve, is open to prevent the gas stored in tank 81 from flowing back into pipe 63.

[0062] The downstream end of the piping 64 is connected to the shower plates 3A and 3B via the flow path of the flow path forming portion 34. Furthermore, regarding the piping 64, a valve V2, a tank 82, and a valve V4 are sequentially provided toward the upstream side. Furthermore, on the upstream side of the valve V4, the piping 64 branches to form piping 64A, 64B, and 64C. A flow rate adjustment mechanism 60 is provided in each of the piping 64A to 64C. Furthermore, the upstream end of the piping 64A is connected to the TMA gas supply source 74, the upstream end of the piping 64B is connected to the NH3 gas supply source 75, and the upstream end of the piping 64C is connected to the N2 gas supply source 76. Either the NH3 gas or the TMA gas is supplied toward the tank 82. The N2 gas supplied from the N2 gas supply source 76 is a diluent gas for the NH3 gas and the TMA gas. The valve V4 is opened while the gases are supplied to and stored in the tank 82 serving as the second storage unit, and is closed while the valve V2 serving as the second valve is open to prevent the gases stored in the tank 82 from flowing back through the pipe 64 .

[0063] Pressure sensors 80 are provided in tanks 81 and 82, respectively, and detection signals of the pressures in tanks 81 and 82 are sent to a control unit 90 described later. The control unit 90 can detect the pressures in tanks 81 and 82 based on the detection signals. In addition, the detection signals are sent to the control unit 90 at intervals shorter than 100 milliseconds, specifically, for example, at intervals of 10 milliseconds, and the control unit 90 can detect the pressures in tanks 81 and 82 at these intervals. The pressure detection interval is shorter than the time it takes to change valves V1 and V2 from one state to the other, between an open state and a closed state. Therefore, as described later, by switching the steps of processing the wafer W by opening and closing valves V1 and V2, the pressures in tanks 81 and 82 can be detected for each step to determine whether there is an abnormality.

[0064] like Figure 1 As shown, the etching apparatus 1 includes a control unit 90, which serves as a computer. This control unit 90 includes software, memory, a CPU, an operation unit, and an alarm output unit. The operation unit is a data input device for the user of the etching apparatus 1 to make various settings, and is comprised of, for example, a touch panel. The operation unit can be used to set actions to be taken when pressure abnormalities occur within tanks 81 and 82, as described later, and various settings related to the treatment process. These various settings are stored in the memory of the control unit 90. The alarm output unit, comprised of, for example, a display and a speaker, notifies the user of abnormalities and determination results, as described later, by displaying a predetermined screen or sounding a predetermined sound as an alarm.

[0065] Commands (steps) are incorporated into the software to enable the processing of wafers W, which will be described later. This software is stored on a storage medium such as an optical disk, hard disk, memory card, magneto-optical disk, or DVD, and is installed in the control unit 90. The control unit 90 uses this software to output control signals to various components of the etching apparatus 1 to control the operation of each component, thereby enabling the processing of wafers W. Specifically, the control unit 90 controls the opening and closing of valves V1 to V4, the opening adjustment of valve V10, the supply of various gases to the downstream side of each pipe by the flow adjustment mechanism 60, the height adjustment of the worktable 5 by the lifting mechanism 58, the raising and lowering of the processing space forming member 41 and the pin 54 by the lifting mechanisms 47 and 56, and the opening and closing of the transfer port 22 by the gate valve 23.

[0066] The software includes a program for performing the following processing: detecting the pressure within tanks 81 and 82 based on the detection signal; determining whether the detected pressure is within a specified range; and performing a response action if the detected pressure is determined not to be within the specified range. Examples of response actions include suspending the processing of the currently executing wafer W and outputting an alarm; outputting an alarm and suspending the processing of the next wafer W to be transferred to the device (processing of the currently executing wafer W continues); or simply outputting an alarm without suspending the processing of the wafer W. Among these actions, the user's pre-set settings are executed.

[0067] Furthermore, before processing the wafers W, the user selects a processing recipe for the wafers W. The processing recipe is a combination of parameters related to the processing conditions for the wafers W, and is stored in the memory of the control unit 90. Specifically, the parameters that make up this combination include the pressure within the processing container 11, the processing temperature of the wafers W, and parameters related to the gases supplied into the processing container 11. These gas-related parameters include the timing and flow rate of gas supply to the downstream side by the flow control mechanisms 60, as well as the timing of opening and closing valves V1 to V4.

[0068] The software includes a program that assists in the production of a processing procedure. This program is a program that calculates the pressures in the tanks 81 and 82 by user input parameters before processing the wafer W, and determines whether the calculated values ​​are appropriate. As a judgment of whether the calculated values ​​are appropriate, in addition to judging whether the pressures in the tanks 81 and 82 storing gas converge within the allowable range (i.e., whether they exceed the upper threshold and the lower threshold), it also includes judging whether the pressure difference in the tanks 81 and 82 when the valves V1 and V2 are switched to the open state converges within the allowable range. In addition, if the calculated value does not converge within the allowable range after judgment, the program is configured to output an alarm to that effect from the alarm output unit.

[0069] The determination of the pressure difference in the tanks 81 and 82 will be further described. As described above, in this example, the gases are supplied toward the shower plate 3 by simultaneously opening the valves V1 and V2 on the downstream sides of the tanks 81 and 82. Assume that when the pressure difference in the tanks 81 and 82 is too large, the gas supplied from one of the tanks 81 and 82 flows toward the other tank via the shower plate 3. In other words, a backflow of gas occurs in the piping system 6. In this case, there is a possibility that an undesirable reaction may occur between the gases, resulting in the inability to process the wafer W normally. In order to prevent such adverse conditions, the program is configured as follows: the pressure difference is determined as described above, and an alarm is output when the setting is inappropriate, thereby prompting the user to reset the parameters. The method for determining the pressure difference will be described in detail after explaining the operation example of the etching device 1.

[0070] Next, refer to the timing diagram Figure 4 , indicating the supply state of gas to the processing container 11 and the flow of gas in the processing container 11 Figure 5 、 Figure 6 The operation example of the etching device 1 is described below. Figures 7 to 12 In this example, TMA gas is used, but the same process can be used even when NH 3 gas is used instead of TMA gas.

[0071] about Figure 4 The timing diagram shows the pressure changes in tanks 81 and 82, the opening and closing states of valves V1 and V2, the timing of supplying HF gas to tank 81, the timing of supplying TMA gas to tank 82, and the pressure changes in the processing container 11 (i.e., the pressure changes in the processing space 4). In addition, the pressure in the processing container 11 changes according to the opening of valve V10, so the pressure change chart shows the changes in the opening of valve V10. Figure 5 、 Figure 6 In FIG. 6 , regarding each pipe constituting the pipe system 6, the portion through which the gas flows is shown thicker than the other portions. Figures 7 to 12 In several figures, HF gas is set as 103 and TMA gas is set as 104 and they are schematically shown respectively.

[0072] First, with the processing space forming member 41 in standby position and the stage 5 in standby position at a relatively low position so as not to interfere with the transfer of the wafers W, two wafers W are transferred into the processing container 11 by the transfer mechanism. Figure 7 Surfaces of the wafers W thus transferred into the processing container 11 are shown. The wafers W are adsorbed onto the respective stages 5 via the pins 54 and brought to a desired temperature, for example, -20°C to 150°C.

[0073] After the transport mechanism retreats from the processing container 11, the processing space-forming member 31 rises to the processing position, forming the processing space 4. Each worktable 5 rises to a predetermined height, approaching the shower plates 3A and 3B, respectively. N2 gas is then supplied from N2 gas supply sources 71A and 71B via the shower plates 3A and 3B to the processing spaces 4A and 4B, respectively. Meanwhile, the opening of valve V10 is adjusted to a predetermined opening (set to a first opening), and the processing spaces 4A and 4B within the processing container 11 are brought to a predetermined pressure.

[0074] The valves V1 and V2 are closed, and the valves V3 and V4 are opened. Then, the HF gas supply source 72 and the N2 gas supply source 73 start to supply HF gas and N2 gas to the empty tank 81, and the TMA gas supply source 74 and the N2 gas supply source 76 start to supply TMA gas and N2 gas to the empty tank 82 (in the diagram, time t1, Figure 6). The respective gases are stored in tanks 81 and 82, and the pressure within these tanks 81 and 82 rises from the initial pressure (first pressure) before the start of gas supply. When the desired second pressure (hereinafter referred to as the release pressure) within tanks 81 and 82 is reached, valves V3 and V4 are closed, while valves V1 and V2 are opened (time t2). Furthermore, at time t2, the opening of valve V10 is changed to a predetermined second opening that is larger than the first opening, and the supply of HF gas, TMA gas, and N2 gas to tanks 81 and 82 is stopped via the flow control mechanism 60.

[0075] By opening valves V1 and V2, the gas stored in tanks 81 and 82 is released into processing spaces 4A and 4B, and rapidly diffuses throughout the processing space 4 ( Figure 6 ). In addition, by changing the opening of the valve V10 to the second opening, the pressure in the processing spaces 4A and 4B drops to a specified pressure (referred to as other pressure). Due to this pressure drop, the gases also diffuse rapidly in the processing spaces 4A and 4B. In addition, at the moment when the gases are released from the tanks 81 and 82 as described above, the pressure in the processing spaces 4A and 4B is made to be a relatively high pressure (referred to as one pressure) in order to prevent adverse conditions caused by excessive differential pressure between the tanks 81 and 82 and the processing spaces 4A and 4B. Specifically, the positional displacement of the wafer W caused by the pressure of the supplied gas and the lifting of particles caused by the airflow formed in the processing container 11 are prevented. In addition, the one pressure and the other pressure of the processing spaces 4A and 4B are, for example, pressures in the range of 0.133Pa to 666Pa.

[0076] The HF gas 103 and the TMA gas 104 diffused into the processing spaces 4A and 4B are adsorbed on the entire surface of the wafer W, that is, the entire surface of the SiOx film 101 and the SiN film 102 ( Figure 8 ). Moreover, due to the difference in incubation time mentioned above, only the SiOx film 101 of the SiOx film 101 and the SiN film 102 starts to be etched ( Figure 9 Then, for example, before the pressures in tanks 81 and 82 return to their initial pressures, valves V1 and V2 are closed (time t3), stopping the supply of gas from tanks 81 and 82 to processing spaces 4A and 4B. The pressures in tanks 81 and 82 at this point are set to the standby pressure (third pressure). Furthermore, by rapidly closing valves V1 and V2, in this example, (standby pressure - initial pressure) > (release pressure - standby pressure).

[0077] HF gas 103 and TMA gas 104 are removed from processing spaces 4A and 4B by exhausting processing spaces 4A and 4B and by the purge action of N2 gas supplied from N2 gas supply sources 71A and 71B. Since the pressure of processing spaces 4A and 4B is reduced to a relatively low pressure, the removal of HF gas 103 and TMA gas 104 is efficiently performed, and the concentration of HF gas 103 and TMA gas 104 in processing spaces 4A and 4B is sharply reduced. Due to this concentration reduction, HF gas 103 and TMA gas 104 adsorbed on SiOx film 101 and SiN film 102 are released from the SiOx film 101 and SiN film 102 into processing spaces 4A and 4B ( Figure 10 、 Figure 11 ). Therefore, the progress of etching of the SiOx film 101 is stopped, and the start of etching of the SiN film 102 is blocked.

[0078] After that, valves V3 and V4 are opened, and the flow rate adjustment mechanism 60 is used to resume the supply of HF gas and N2 gas to tank 81 and the supply of TMA gas and N2 gas to tank 82. The opening of valve V10 is restored to the first opening (time t4), and the pressures in the processing spaces 4A and 4B rise and return to the same pressure. Thus, at time t4, the same operation as at time t1 is performed, and the state of the processing container 11 is restored. Figure 5 status.

[0079] When the pressure in the tanks 81 and 82 rises from the standby pressure and becomes the release pressure, the same action as at time t2 is performed. That is, the valves V3 and V4 are closed, the valves V1 and V2 are opened, the opening of the valve V10 is changed to the second opening, and the HF gas, TMA gas and N2 gas are supplied to the tanks 81 and 82 by the flow adjustment mechanism 60 and then stopped (at time t5). Therefore, the action of the device at this time t5 is the same as the action at time t2. Through this action, the gas stored in the tanks 81 and 82 is released to the processing spaces 4A and 4B, and on the other hand, the pressure in the processing spaces 4A and 4B drops to other pressures. As the processing container 11, it becomes Figure 6 state, and the selective etching of the SiOx film 101 is started again.

[0080] Then, similarly to time t3, valves V1 and V2 are closed (time t6), and HF gas 103 and TMA gas 104 are removed from processing chambers 4A and 4B. The progress of etching of SiOx film 101 is stopped, and the start of etching of SiN film 102 is blocked. Furthermore, valves V3 and V4 are opened, and the supply of HF gas and N2 gas to tank 81 and TMA gas and N2 gas to tank 82 is resumed. The opening of valve V10 is restored to the first opening (time t7). That is, at time t7, the device operates similarly to time t4. Furthermore, when the pressure within tanks 81 and 82 rises from the standby pressure and reaches the release pressure, the same operations as at times t2 and t5 are performed (time t8).

[0081] In this way, at time t5 to t8, the series of actions from time t2 to t5 is repeated. Moreover, the same actions are repeated after time t8. By performing the cycle in this way, the selective etching of the SiOx film 101 is repeated. When the predetermined number of cycles are completed and the etching amount of the SiOx film 101 reaches the desired amount ( Figure 12 ), each wafer W is carried out from the processing container 11 in the reverse process of carrying the wafers W into the processing container 11.

[0082] As described above, a step of storing gas in tanks 81 and 82 (referred to as an initial storing step) is first performed. Then, wafers W are processed by repeating a cycle consisting of a gas release step of releasing gas from tanks 81 and 82 into processing space 4, an exhaust step of stopping the release of gas from tanks 81 and 82 and exhausting each gas from processing space 4, and a re-storage step of supplying the released amount of gas to tanks 81 and 82. The exhaust step and the re-storage step are performed in parallel.

[0083] Furthermore, the gas release step occurs while valves V1 and V2 are open, corresponding to the periods between t2 and t3 and t5 and t6. The duration of a single gas release step is relatively short, for example, less than one second. Therefore, in the aforementioned treatment example, when valves V1 and V2 are open, not all of the gas in tanks 81 and 82 is released into the treatment space 4, and some gas remains. Consequently, the initial gas storage step (between t1 and t2) of storing gas in empty tanks 81 and 82 is longer than the secondary gas storage step (between t4 and t5 and t7 and t8).

[0084] As described above, in the etching apparatus 1, by opening valves V1 and V2, a relatively large amount of HF gas and TMA gas, which have been pressurized by being stored in tanks 81 and 82, is released into the processing space 4. Consequently, the HF gas and TMA gas quickly spread throughout the processing space 4, and are thereby adsorbed onto the SiOx film 101 at various locations within the surface of the wafer W simultaneously or substantially simultaneously, thereby initiating etching. Consequently, the uniformity of etching the SiOx film 101 within the surface of the wafer W can be improved. Furthermore, after the valves V1 and V2 are opened, the valves V1 and V2 are quickly closed. Specifically, by closing valves V1 and V2 before the pressure within the tanks 81 and 82 returns to its initial pressure, etching of the SiN film 102 can be suppressed, and etching of the SiOx film 101 can be selectively performed.

[0085] In addition, the cycle after the initial storage step (time t1-t2 period) is described as being repeated three times or more in the above description, but the number of repetitions is arbitrary. In addition, when the required etching amount is small, the cycle can be performed only once without repeating the cycle.

[0086] In the above process, the pressure in the processing space 4 is reduced by changing the opening of valve V10 while valves V1 and V2 are opened. However, the opening of valve V10 may be changed at a timing slightly before or after the opening of valves V1 and V2 by a predetermined time. Changing the opening of valve V10 at a timing slightly before or after the opening of valves V1 and V2 in this manner also includes reducing the pressure in the processing container at a timing corresponding to the opening of the valves, similar to changing the opening of valve V10 at the same opening time.

[0087] In addition, during the execution of the above-mentioned initial storage step and the subsequent cycles, detection signals are continuously sent from the pressure sensors 80 of the tanks 81 and 82 to the control unit 90 at a specified interval to monitor the pressure inside the tanks 81 and 82. The interval for sending the detection signal is shorter than the time for opening the valves V1 and V2 to perform the gas release step (during the time t2-t3 and the time t5-t6). Therefore, the pressure is detected separately for the gas release step in which the valves V1 and V2 are opened and for the other steps in which the valves V1 and V2 are closed. That is, with respect to the valves V1 and V2, the pressure is detected during each opening period and each closing period. Moreover, the presence or absence of abnormalities is monitored based on the pressure. Therefore, abnormalities in the operation of the device can be quickly discovered, and the yield of semiconductor products manufactured from the wafer W can be prevented from decreasing.

[0088] Supplementary explanation will be given regarding the determination of the pressure difference within tanks 81 and 82, which is used to assist the user in creating a process. To determine this pressure difference, the pressure within tanks 81 and 82 is calculated when the downstream valve V1 or V2 is open. Tank 81 will be described below. Assuming that the volume (unit: cc) of tank 81 is constant, the pressure within tank 81 varies depending on the amount of gas supplied to tank 81 (unit: cc) and the amount of gas discharged from tank 81 (unit: cc). The amount of gas discharged is affected by the pressure within tank 81, but if valve V1 is only open for a very short period of time, it can be assumed that the amount of gas discharged varies solely with the pressure within tank 81. Furthermore, in a stable operating state (the state after time t2 in the aforementioned graph, where valves V1 and V2 are repeatedly opened and closed), the pressure within tank 81 is the same at each time valve V1 is opened, and the gas supply amount equals the gas discharge amount. The gas supply amount is the flow rate of the gas supplied to the tank 81×time. Since HF gas and N 2 gas are supplied to the tank 81 , the gas flow rate is (HF gas flow rate+N 2 gas flow rate).

[0089] Under the above premise, users will Figure 4 The time from time t1 to time 2 (i.e., the time from filling the empty tank 81 with gas until valve V1 is opened) and the flow rates of HF gas and N2 gas supplied to the tank 81 from the flow control mechanism 60 located upstream of the tank 81 are set as parameters. The time from time t1 to time 2 multiplied by (HF gas flow rate + N2 gas flow rate) is the gas supply rate to the tank 81, which is set to a value that does not exceed the volume of the tank 81. The pressure within the tank 81 when valve V1 is opened at time t2 is automatically calculated using this gas supply rate, the volume of the tank 81, and a predetermined calculation formula.

[0090] Furthermore, as described above, the amount of gas ejected based on the opening of the valve V1 is determined by the pressure within the tank 81. Based on the calculated pressure of the tank 81 when the valve V1 is opened, the amount of gas ejected is calculated using a predetermined formula. As described above, the amount of gas ejected = the amount of gas supplied to compensate for the pressure drop. Furthermore, since the flow rate of HF gas + the flow rate of N2 gas are already set, the time required to refill the tank 81 with gas can also be automatically calculated based on the gas flow rate and the gas supply amount ( Figure 4 The time between time t4 and time t5, the time between time t7 and time t8 of the graph are displayed and the user is informed.

[0091] As described above, the pressure within tank 81 when valve V1 is open can be calculated based on the user's settings. Similarly, the pressure within tank 82 when valve V2 is open can be calculated based on the flow rates of the gases supplied to tank 82 and the time settings from time t1 to time t2. The flow rates and supply times of the gases supplied to tank 81 set by the user correspond to the first parameter, while the flow rates and supply times of the gases supplied to tank 82 correspond to the second parameter. For the pressures (virtual pressures) within tanks 81 and 82 thus calculated, the difference between the pressures within tank 81 and 82 at the same time (virtual pressure difference) is calculated, and a determination is made as to whether this calculated value falls within the allowable range (i.e., to detect the presence of an abnormality).

[0092] Because the period during which valve V1 is open is extremely short, it appears that the change in tank 81's pressure is constant and the amount of gas discharged varies solely based on the pressure within tank 81. However, in reality, the change in tank 81's pressure and the amount of gas discharged vary depending on the pressure within tank 81 and the duration of valve V1's opening. As described above, the pressure within tank 81 at the time valve V1 is opened at time t2 is automatically calculated. However, a predetermined formula can also be prepared to calculate the pressure after valve V1 is fully opened based on the duration of valve V1's opening and the pressure within tank 81 at the time of valve V1's opening. Furthermore, the pressure within tank 81 after valve V1 is fully opened, calculated using this formula, can be used to calculate the time required to refill tank 81 with gas after valve V1 is fully opened, as described above. Furthermore, if gas is supplied to tank 81 while valve V1 is open, the decrease in tank 81's pressure due to valve V1 opening will be reduced by the amount of gas supplied, affecting the amount of gas discharged from tank 81 and the change in tank 81's pressure. Therefore, the above calculation formula is set to calculate the pressure after valve V1 is completely opened based on the gas supply time and flow rate during the period when valve V1 is open. The user sets the opening time of valve V1, the gas supply time to tank 81 during the period when valve V1 is open, and the gas flow rate to be supplied.

[0093] When calculating the pressure in the tank 81, the amount of pressure increase in the tank 81 is calculated by multiplying the flow rate of each gas to the tank 81 by the supply time and the predetermined coefficient. Furthermore, the pressure drop in the tank 81 is considered to be caused by an amount corresponding to the opening time of the valve V1, and the amount of pressure drop in the tank 81 is calculated by multiplying the opening time of the valve V1 by the predetermined coefficient. Figure 4The time between moments t1 and t2 and the flow rates of HF gas and N2 gas supplied to tank 81 are set by the user. In addition, the time between moments t5 and t6 when valve V1 is opened during the execution of the cycle, the time between moments t4 and t5 during the re-storage step during the execution of the cycle, and the flow rates of HF gas and N2 gas supplied to tank 81 are set by the user. The pressure inside tank 81 at moments t2 and t5 when valve V1 is opened can also be calculated by this setting. By setting the parameters in tank 82 in the same way, the pressure at moments t2 and t5 when valve V2 is opened can be calculated. Furthermore, the pressure difference inside tanks 81 and 82 at each moment t2 and t5 can be calculated, and a determination can be made as to whether it is within the allowable range. In addition, it is described as monitoring the respective pressures inside tanks 81 and 82 during the processing of wafer W, but the pressure difference inside tanks 81 and 82 can also be calculated in the same way as when the processing recipe is prepared, and a determination can be made as to whether there is an abnormality based on this pressure difference.

[0094] In addition, when using a gas that causes the reaction of the wafer W to progress by the interaction of two gases, such as the HF gas and TMA gas exemplified, it is sufficient to set the state in which each gas is supplied to the wafer W. That is, during the period in which one gas is adsorbed on the wafer W (during the period in which the separation from the wafer W is not completed), the other gas can be supplied to the wafer W. Therefore, it is not limited to supplying each gas to the wafer W at the same time, and each gas can also be supplied to the wafer W alternately. That is, during Figure 4 In the illustrated process, the periods during which the valves V1 and V2 are open coincide with each other. However, the periods during which the valve V1 is open and the periods during which the valve V2 is open may be staggered with each other.

[0095] Figure 13 The timing chart shown in the figure shows an example of processing in which the periods during which valves V1 and V2 are opened are staggered. Figure 4 The processing of the timing diagram is set to delay the timing of opening the valve V2 and supplying the TMA gas into the tank 82. Specifically, the processing is repeated in sequence by opening the valve V1 to release the HF gas into the processing space 4, closing the valve V1, releasing the TMA gas into the processing space 4 by opening the valve V2, and closing the valve V2. An interval is left between closing one of the valves V1 and V2 and opening the other, during which the processing space 4 is purged and exhausted. However, from the time when one etching gas is supplied to the wafer W to the time when another etching gas is supplied, the etching gas is separated from the SiOx film 101. Therefore, from the viewpoint of improving the productivity of the device by improving the etching property of the SiOx film 101, it is preferred to perform the above steps as in Figure 4 The periods during which the valves V1 and V2 are open are made consistent as in the process described in .

[0096] Alternatively, the timing of opening valves V1 and V2 can be staggered, so that their opening periods overlap. Thus, for example, by opening valve V2 slightly later than valve V1, both valves V1 and V2 can be opened, and gases can be supplied from tanks 81 and 82 to the processing space 4. However, to prevent backflow of gases from one tank to the other via the shower plate 3, valves V1 and V2 are preferably opened simultaneously.

[0097] In addition, in order to quickly diffuse the gas supplied from the tanks 81 and 82 in the processing space 4, it is preferable that the volume of the processing space 4 is as small as possible. Figure 5 、 Figure 6 As shown in the example, the worktable 5 is preferably positioned close to the shower plate 3, which forms the top of the processing container 11. However, depending on the processing process, it is not desirable to position the worktable 5 too close to the shower plate 3. For example, in a processing process in which the pressure within the tanks 81 and 82 is relatively high when valves V1 and V2 are open, the ejection pressure of the gas from the shower plate 3 becomes excessively high, and the area directly below the gas ejection port 33 of the shower plate 3 on the surface of the wafer W is considered to be damaged.

[0098] Therefore, when the wafers W are processed, the stage 5 may be positioned at the same height. However, it is preferably positioned at a height that matches the processing conditions of the wafers W. Figure 14 and Figure 5 Similarly, a longitudinal sectional side view of the etching apparatus 1 during the processing of the wafer W is shown. Figure 5 Compared with the example shown, the height position of the workbench 5 is lower. The following operation can be performed: when the pressure in the tanks 81 and 82 is relatively low when the valves V1 and V2 are open, Figure 5 When the pressure in the tanks 81 and 82 is relatively low when the valves V1 and V2 are opened, the workbench 5 is arranged at the height shown in FIG. Figure 14 When the height of the workbench 5 is changed as shown, it is preferable to change the distance H1 between the upper surface of the workbench 5 and the shower plate 3 within a range of, for example, 10 mm to 100 mm (see Figure 14 ). In addition, when the user of the apparatus sets multiple processing recipes, he or she also sets the height of the worktable 5 corresponding to each processing recipe, and stores the corresponding height in the memory of the control unit 90. Alternatively, the following operation can be performed: when the user selects a processing recipe to be used from multiple processing recipes, the worktable 5 is positioned at the height corresponding to the selected processing recipe (i.e., the selected processing conditions) according to the data in the memory, and the wafer W is processed.

[0099] In the etching apparatus 1, HF is used as the halogen-containing gas, and NH₃ or TMA gas is used as the alkaline gas to etch the SiOx film, but the etching process is not limited to this. For example, the film to be etched may be a Si film containing oxygen other than the SiOx film, or a SiOCN film. Alternatively, a silicon oxide film using tetraethyl orthosilicate gas as the raw material may be used. Furthermore, as the halogen-containing gas, HCl, HBr, HI, SF₆, and other gases may be used in addition to HF.

[0100] When etching Si films containing oxygen, amines other than TMA can be used. Specifically, gases of various amine compounds such as dimethylamine, dimethylethylamine, diethylamine, triethylamine, mono-tert-butylamine, pyrrolidine, and pyridine can be used. Furthermore, as other specific examples of amine compounds, compounds in which some or all of the C-H bonds of the above compounds are replaced with C-F bonds (such as 1,1,1-trifluorodimethylamine) can be used.

[0101] Furthermore, when etching is performed using the etching apparatus 1, it is particularly effective to expose films having different incubation times, such as the SiOx film 101 and the SiN film 102, on the wafer W, and selectively etch the film having the shorter incubation time. However, the films to be etched are not limited to this. For example, the etching apparatus 1 can be used even when only a single film is exposed on the surface of the wafer W and this film is the film to be etched.

[0102] Furthermore, the film to be etched is not limited to the aforementioned oxygen-containing Si film; other Si-containing films may also be used. Specifically, it may be a Si film, SiGe film, or other silicon-containing film. When etching these Si and SiGe films, F2 gas, IF7 gas, IF5 gas, ClF3 gas, SF6 gas, or the like can be used as a halogen-containing gas, and NH3 gas can be used as an alkaline gas. Furthermore, in this specification, when a compound constituting a film or gas "contains" a substance, it does not mean that the substance is contained as an impurity, but rather that the substance is contained as a primary component of the compound.

[0103] For example, when etching a Si film using F2 and NH3 gases, depending on the processing temperature of the wafer W when these gases are supplied, AFS ((NH4)SiF6) remains due to the denaturation of the Si film. This AFS is then removed by heating the wafer W. Etching in this application includes not only removing the film with the gases but also simply denaturing it. In other words, the process of denaturing the Si film into AFS is also included in the etching process.

[0104] In addition, although it has been described that one of NH3 gas and amine gas is selected for use, both gases can also be used. Therefore, a mixed gas composed of these NH3 gases and amine gases can also be supplied to the wafer W. In addition, when supplying the wafer W as a mixed gas like this, the NH3 gas and the amine gas can be stored together in the above-mentioned tank 82, or the NH3 gas and the amine gas can be stored separately in the tank and mixed when supplied to the processing container 11. Therefore, the circuit (supply path) for setting the tank is not limited to two. In addition, the halogen-containing gas and the alkaline gas can also be stored in the same common tank. However, as mentioned above, the halogen-containing gas and the alkaline gas may react with each other while being stored in the tank, so it is preferred to store them in different tanks as described so far.

[0105] In addition, when the wafer W is processed by the tanks 81 and 82, Figure 4 、 Figure 13 In the process of the diagram described above, after the gas is released, the valves V1 and V2 are quickly closed, but the process is not limited to this. As an example of this process, Figure 15 The process shown in the diagram (for the sake of convenience, it is recorded as a continuous supply process) is to Figure 4 The following description will focus on the differences between the processes described (sometimes referred to as pulse supply processes). Figure 15 At time t11 in the pulse supply process, HF gas and TMA gas begin to be supplied to tanks 81 and 82, respectively. Therefore, the operation at time t11 is the same as the operation at time t1 in the pulse supply process. Thereafter, at time t12, valves V1 and V2 are opened to supply gas from tanks 81 and 82 to processing spaces 3A and 3B. The operation at time t12 differs from the operation at time t2 in the pulse supply process in that valves V3 and V4 are not closed, and the supply of HF gas and N2 gas from HF gas supply source 72 and N2 gas supply source 73 to tank 81, and the supply of TMA gas and N2 gas from TMA gas supply source 74 and N2 gas supply source 76 to tank 82, continue.

[0106] After the pressure in tanks 81 and 82 drops sharply due to the release of the pressurized gas inside, it slowly drops back to its initial pressure. Valves V1 to V4 are closed, and the flow rate adjustment mechanism 60 stops the supply of gas from each gas supply source to tanks 81 and 82. The opening of valve V10 is changed from the first opening to the second opening (time t13). The pressure in processing space 4 then drops from one pressure to another, and exhaust of the gases from processing space 4 progresses.

[0107] By repeating the above series of actions as a cycle, a desired amount of SiOx film 101 is etched. In such a process, HF gas and TMA gas can be quickly diffused to the entire surface of the wafer W, so that the SiOx film 101 can be etched with high uniformity in all parts of the surface of the wafer W. However, the SiN film 102 is exposed to HF gas and TMA gas for a relatively long time. Therefore, in order to improve the etching selectivity of the SiOx film 101, the SiN film 102 is exposed to HF gas and TMA gas for a relatively long time. Figure 4 The pulse supply process described is effective.

[0108] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The embodiments described above may be omitted, replaced, modified, and combined in various ways without departing from the scope of the appended claims and the spirit thereof.

[0109] 〔Evaluation Test〕

[0110] The following describes evaluation tests conducted in conjunction with this technology. In these evaluation tests, a substrate with a pattern formed thereon was processed using an etching apparatus 1, and the pattern was observed before and after etching. Furthermore, the etching amount of the SiOx film 101 and SiN film 102 exposed on the surface of the wafer W and forming the pattern was measured before and after etching, and the selectivity ratio (= etching amount of SiOx film 101 / etching amount of SiN film 102) was calculated. Evaluation Tests 1-1 to 1-3 were conducted using different etching methods.

[0111] As evaluation test 1-1, Figure 16 As shown in the timing diagram of the device, the operation of each part of the device is carried out to perform the processing. Figure 16 Treatment (set to non-pressurized treatment), description and Figure 4 The difference between the pulse supply processing. At time t21, each gas is supplied to the tanks 81 and 82 through the flow adjustment mechanism 60, and on the other hand, the closed valves V1 and V2 are opened. Then, at time t22, the valves V1 and V2 are closed, and the valve V10 set to the first opening is set to the second opening to reduce the pressure in the processing container 11. When the above series of processes are regarded as a cycle, the wafer W is etched by repeating the cycle 5 times. In this way, in the evaluation test 1-1, tanks 81 and 82 are provided, but in order to prevent the tanks 81 and 82 from playing the role of storing and pressurizing the gas, each gas is supplied to the processing space 4. As an evaluation test 1-2, the process is carried out by Figure 15 The continuous supply process described above was carried out 5 times. Figure 4 The number of cycles after the initial storage step was set to 25.

[0112] The selectivity ratio was 1.2 in Evaluation Test 1-1, 3.1 in Evaluation Test 1-2, and 52.3 in Evaluation Test 1-3. Therefore, Evaluation Test 1-3 was the most favorable result, while Evaluation Test 1-2 was the second most favorable result. These test results confirm the effectiveness of storing HF gas and TMA gas in tanks 81 and 82, respectively, before supplying them to the processing vessel 11. Furthermore, regarding valves V1 and V2, closing valves V1 and V2 before the gases are completely released from tanks 81 and 82 and the pressures within tanks 81 and 82 return to their initial levels is effective.

[0113] Description of Reference Numerals

[0114] W: wafer; 11: processing container; 63, 64: piping; 72, 74: gas supply source; 81, 82: tank.

Claims

1. An etching method comprising the following steps: supplying a first etching gas and a second etching gas including at least one of ammonia gas and amine gas from a gas supply source to the gas supply path; a storing step of storing the first etching gas and the second etching gas in a storage portion provided in the gas supply path and increasing the pressure inside the storage portion; and In the gas supply process, a valve provided on the downstream side of the storage portion in the gas supply path is opened to supply the first etching gas and the second etching gas stored in the storage portion to a processing container in which a substrate is stored, so as to etch the first film formed on the substrate.

2. The etching method according to claim 1, wherein The first etching gas is a halogen-containing gas, The first film is a silicon-containing film.

3. The etching method according to claim 2, wherein: The method further includes an opening and closing step of repeatedly opening and closing the valve to repeat the gas supply step, thereby repeatedly etching the first film.

4. The etching method according to claim 3, wherein: The storage process comprises: an initial storage step of changing the pressure in the storage portion from a first pressure to a second pressure higher than the first pressure; and a restoring step of restoring the pressure in the storage unit, which has reached a third pressure lower than the second pressure and higher than the first pressure by performing the gas supply step, back to the second pressure; A cycle consisting of the gas supply step and the restorage step is repeated.

5. The etching method according to claim 3, comprising the following steps: At a timing corresponding to the opening of the valve, the pressure in the processing container is reduced from one pressure to another pressure; and From the time the valve is opened until the valve is opened next time, the pressure in the processing container is increased from the other pressure to the one pressure.

6. The etching method according to claim 2, wherein: The storage portion includes a first storage portion and a second storage portion, The valve comprises a first valve and a second valve, The storage step includes storing the first etching gas in a first storage portion and storing the second etching gas in a second storage portion. The gas supply step includes opening the first valve provided on the downstream side of the first storage unit and the second valve provided on the downstream side of the second storage unit.

7. The etching method according to claim 6, wherein: The gas supply step includes a step of simultaneously opening the first valve and the second valve.

8. The etching method according to claim 2, wherein: A second film of a different type from the first film is formed on the substrate, The valve is closed and the process container is exhausted to selectively etch the first film among the first film and the second film.

9. The etching method according to claim 8, wherein: The first film is a silicon oxide film, and the second film is a silicon nitride film.

10. The etching method according to claim 1, wherein The method further includes the step of raising and lowering a table on which the substrate is placed in the processing container by a driving mechanism to change the distance between the table and the top of the processing container. The gas supplying step includes supplying the first etching gas and the second etching gas to the substrate positioned on the stage at a height set according to processing conditions of the substrate.

11. The etching method according to claim 3, comprising the following steps: detecting the pressure in the storage portion by a pressure sensor; and The presence or absence of abnormality is determined based on the pressure.

12. The etching method according to claim 11, wherein The pressure detection is performed for the valve that is repeatedly opened and closed during each opening period and each closing period of the valve.

13. The etching method according to claim 1, wherein: A plurality of work tables for placing the substrates in the processing container are provided in the processing container. The gas supply step includes a step of collectively supplying the first etching gas and the second etching gas to the substrates placed on the respective stages.

14. An etching device comprising: a gas supply source for supplying a first etching gas and a second etching gas including at least one of ammonia gas and amine gas; a gas flow path for supplying the first etching gas and the second etching gas from the gas supply source; a processing container that stores the substrate on which the first film is formed, and the processing container is connected to the downstream end of the gas flow path; a storage portion provided in the gas flow path; and A valve is provided on the downstream side of the storage portion in the gas flow path. After the valve is closed to store the first etching gas and the second etching gas in the storage portion and the internal pressure of the storage portion is increased, the valve is opened to supply the first etching gas and the second etching gas into the processing container to etch the first film.

15. A software for an etching device, comprising the following steps: supplying a first etching gas and a second etching gas including at least one of ammonia gas and amine gas from a gas supply source to the gas supply path; a storing step of storing the first etching gas and the second etching gas in a storage portion provided in the gas supply path to increase the pressure inside the storage portion; as well as The gas supply step opens a valve provided on the downstream side of the storage portion in the gas supply path to supply the first etching gas and the second etching gas stored in the storage portion to a processing container in which a substrate is stored, so as to etch the first film formed on the substrate.

16. The software according to claim 15, wherein: The storage portion includes a first storage portion and a second storage portion, The valve comprises a first valve and a second valve, The storing step includes storing the first etching gas in a first storage portion and storing the second etching gas in a second storage portion. The gas supply step includes simultaneously opening the first valve provided on the downstream side of the first storage unit and the second valve provided on the downstream side of the second storage unit. The software performs the following steps: detecting an abnormality in the difference between the virtual pressures in the first storage section and the second storage section based on a first parameter set for calculating the virtual pressure in the first storage section and a second parameter set for calculating the virtual pressure in the second storage section.

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