Gas treatment device

Abstract

The invention provides a gas processing apparatus. The gas processing apparatus is configured to be provided with: a facing part which faces a mounting part of a substrate in a vacuum container and which is provided with a plurality of first gas ejection ports; a first diffusion space for the process gas provided above the facing portion so as to communicate with each of the first gas ejection ports; a plurality of second gas discharge ports opened in the vertical direction at the top facing the first diffusion space from above the first diffusion space; a second diffusion space for the process gas provided above the top so as to communicate with each of the second gas ejection ports; and a plurality of third gas ejection ports opened in an oblique direction having a greater inclination with respect to the vertical axis than the inclination of the second gas ejection ports with respect to the vertical axis, on the outer side of the region in which the second gas ejection ports are opened in the ceiling portion. Columns are formed along the circumferential direction of the first diffusion space and are respectively communicated with the second diffusion space.

Description

[0001] This application is a divisional application of an application with a filing date of August 9, 2019, application number 201910733817.2, and invention name “Gas Processing Device and Gas Processing Method”. Technical Field

[0002] The present disclosure relates to a gas processing device and a gas processing method. Background Art

[0003] As a gas treatment for a semiconductor wafer (hereinafter referred to as a "wafer") serving as a substrate, for example, ALD (Atomic Layer Deposition) and CVD (Chemical Vapor Deposition) are sometimes used to form a film. In such a gas treatment, for example, gas is supplied to the wafer in a spraying manner. Patent document 1 shows a film forming device for performing CVD (Chemical Vapor Deposition) by supplying gas to a mounting table for mounting a wafer. The film forming device is provided with a base for supporting the wafer and a shower head arranged above the base. The shower head includes a first porous plate (panel) and a second porous plate (blocking plate), the first porous plate (panel) facing the wafer and having a large number of holes; the second porous plate (blocking plate) constitutes the shower head, and is arranged above the first porous plate in a manner that divides the diffusion space of the gas in the up and down directions.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2002-69650 Summary of the invention

[0005] Problem that the invention aims to solve

[0006] The present disclosure provides a technology capable of performing gas processing with high uniformity within the surface of a substrate.

[0007] Solutions for solving problems

[0008] The gas processing device disclosed in the present invention comprises:

[0009] a vacuum container, wherein a vacuum atmosphere is formed inside the vacuum container;

[0010] a loading portion, which is disposed in the vacuum container and is used to load a substrate;

[0011] an opposing portion, which is opposed to the mounting portion and has a plurality of first gas ejection ports for ejecting a processing gas in a shower shape toward the substrate to perform gas processing;

[0012] A first diffusion space for the processing gas is provided above the facing portion in a manner communicating with each of the first gas ejection ports;

[0013] a plurality of second gas ejection ports, which are opened in a top portion of the first diffusion space and facing the first diffusion space in a vertical direction, and are used to supply the processing gas in a spraying manner to a central portion of the first diffusion space;

[0014] A second diffusion space for the processing gas is provided above the top portion in communication with each of the second gas ejection ports;

[0015] a gas supply path provided on an upstream side of the second diffusion space and configured to supply the processing gas to the second diffusion space; and

[0016] A plurality of third gas ejection ports are provided on the outer side of the region in the top portion where each of the second gas ejection ports is provided, along an inclined direction with respect to a vertical axis which is more inclined than the inclination of the second gas ejection ports with respect to the vertical axis, so as to eject the processing gas radially from the central portion side to the peripheral portion side of the first diffusion space, and the plurality of third gas ejection ports form a row along the circumferential direction of the first diffusion space and are respectively connected to the second diffusion space.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to perform gas processing with high uniformity within the surface of a substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a longitudinal sectional side view of the film forming apparatus according to one embodiment of the present disclosure.

[0020] Figure 2 It is a longitudinal sectional side view of the shower plate and the upper shower head constituting the film forming device.

[0021] Figure 3 4 is a perspective view of the lower surface side of the upper shower head.

[0022] Figure 4 4 is a perspective view of the upper surface side of the upper shower head.

[0023] Figure 5 4 is a cross-sectional top view of the upper shower head.

[0024] Figure 6 It is a perspective view of a flow path provided in the film forming apparatus.

[0025] Figure 7 is a top view of the flow path.

[0026] Figure 8 It is a schematic diagram for explaining the process performed by the film forming apparatus.

[0027] Fig. 9 It is a schematic diagram for explaining the process performed by the film forming apparatus.

[0028] Fig.10 It is a schematic diagram for explaining the process performed by the film forming apparatus.

[0029] Fig.11 is a timing chart of the processing performed by the film forming apparatus.

[0030] Fig.12 It is a top view of the wafer showing the results of the evaluation test.

[0031] Fig.13 It is a top view of the wafer showing the results of the evaluation test. DETAILED DESCRIPTION

[0032] Reference Figure 1 A film forming device 1 as an embodiment of a gas processing device disclosed in the present invention is illustrated with a longitudinal sectional side view. The film forming device 1 includes a flat circular processing container 11. A vacuum atmosphere is formed in the processing container 11, and a circular substrate, i.e., a wafer W, having a diameter of, for example, 300 mm is stored. The film forming device 1 repeatedly supplies TiCl4 (titanium tetrachloride) gas as a raw material gas and NH3 (ammonia) gas as a reaction gas to the wafer W alternately to perform ALD, thereby forming a TiN (titanium nitride) film. Between the time period when the TiCl4 gas as the first processing gas is supplied and the time period when the NH3 gas as the second processing gas is supplied, N2 (nitrogen) gas as an inert gas is supplied as a purge gas. By supplying the purge gas, the atmosphere in the processing container 11 is replaced from the TiCl4 gas atmosphere or the NH3 gas atmosphere to the N2 gas atmosphere. In addition, in the film formation process using ALD, N 2 gas is continuously supplied into the process container 11 as a carrier gas for introducing TiCl 4 gas and NH 3 gas into the process container 11 .

[0033] The side wall of the processing container 11 is provided with a wafer loading / unloading port 12 and a gate valve 13 for opening and closing the loading / unloading port 12. An exhaust duct 14 is provided on the upper side of the loading / unloading port 12. The exhaust duct 14 is formed by bending a duct having a rectangular longitudinal cross-section in a circular ring shape, and constitutes a part of the side wall of the processing container 11. A slit-shaped opening 15 extending in the circumferential direction is formed on the inner peripheral surface of the exhaust duct 14, and the opening 15 constitutes the exhaust port of the processing container 11.

[0034] In addition, the exhaust duct 14 is connected to one end of an exhaust pipe 16. The other end of the exhaust pipe 16 is connected to an exhaust mechanism 17 composed of a vacuum pump. A pressure adjustment mechanism 18 composed of, for example, a valve for adjusting pressure is provided in the exhaust pipe 16. The opening of the valve for adjusting pressure is adjusted based on a control signal output from the control unit 10 described later, so that the pressure in the processing container 11 is adjusted to a desired vacuum pressure.

[0035] In the figure, 21 is a circular mounting table horizontally arranged in the processing container 11 for mounting the wafer W. The wafer W is mounted in such a manner that its center is aligned with the center of the mounting table. A heater 22 is embedded in the mounting table 21 forming a mounting portion. The heater 22 heats the wafer W to 400°C to 700°C, for example. The upper end of a supporting member 23 that passes through the bottom of the processing container 11 and extends in the up-down direction is connected to the central portion of the lower surface side of the mounting table 21, and the lower end of the supporting member 23 is connected to a lifting mechanism 24. The mounting table 21 is moved up and down by the lifting mechanism 24. Figure 1 The lower position (processing position) indicated by the dotted line in Figure 1 The lower position is a position for delivering the wafer W to the transport mechanism of the wafer W entering the processing container 11 from the above-mentioned loading and unloading port 12. The upper position is a position for processing the wafer W.

[0036] Reference numeral 25 in the figure denotes a flange disposed below the bottom of the processing container 11 in the supporting member 23. Reference numeral 26 in the figure denotes a retractable bellows, the upper end of which is connected to the bottom of the processing container 11, and the lower end of which is connected to the flange 25, and the bellows ensures the airtightness in the processing container 11. Reference numeral 27 in the figure denotes three (only two are shown in the figure) supporting pins, and reference numeral 28 in the figure denotes a lifting mechanism for lifting and lowering the supporting pins 27. When the stage 21 is located at the handover position, the supporting pins 27 are lifted and lowered via the through holes 29 disposed on the stage 21, thereby protruding and retracting relative to the upper surface of the stage 21, thereby performing the handover of the wafer W between the stage 21 and the above-mentioned conveying mechanism.

[0037] A gas supply path forming portion 3 is provided on the upper side of the exhaust duct 14 to seal the inside of the processing container 11 from the upper side of the processing container 11. The gas supply path forming portion 3 includes a main body 31 and a gas inlet portion 32. The main body 31 is configured as a flat circular block, and the peripheral portion of the main body 31 is provided along the exhaust duct 14 and supported on the exhaust duct 14. A cooling mechanism for adjusting the temperature of the gas supply path forming portion 3 is provided on the upper side of the main body 31, but is omitted from the figure. The gas inlet portion 32 is formed by bulging upward along the radial direction of the upper surface of the main body 31.

[0038] The main body 31 is further described in detail. A circular top forming portion 33 is formed in the central lower portion of the main body 31, and the top forming portion 33 protrudes in the processing container 11 toward the mounting table 21 and constitutes the top of the processing container 11. The peripheral portion of the top forming portion 33 further extends downward to form an annular supporting protrusion 34, and a circular plate-shaped shower plate 35 is horizontally supported at the lower end of the supporting protrusion 34. The space surrounded and divided by the upper surface of the supporting protrusion 34 and the shower plate 35 is a first diffusion space 39 for diffusing each gas supplied from the upper shower head 42 described later in the lateral direction, and the first diffusion space 39 is configured as a flat circle.

[0039] The shower plate 35 is described. The shower plate 35 forms a facing portion that is disposed in a manner that faces the surface of the mounting table 21. Moreover, the upper surface of the shower plate 35 that defines the first diffusion space 39 is formed horizontally and flatly. In addition, the peripheral portion of the shower plate 35 is disposed along the above-mentioned support protrusion 34. The lower peripheral portion of the shower plate 35 protrudes downward to form a circular ring-shaped processing space forming protrusion 36, which is close to the peripheral portion of the mounting table 21 located at the upper position as described above. The space sandwiched between the shower plate 35 and the mounting table 21 located at the upper position and surrounded by the processing space forming protrusion 36 constitutes a processing space 37 for processing the wafer W. In the area surrounded by the processing space forming protrusion 36 in the shower plate 35, a large number of first gas ejection ports 38 are respectively punched in the thickness direction of the plate, that is, in the vertical direction. Therefore, the first gas ejection ports 38 are connected to the processing space 37 and the first diffusion space 39, respectively.

[0040] On the lower surface of the top forming portion 33 forming the first diffusion space 39, a recess is formed in the central portion of the area surrounded by the supporting protrusion 34, and a horizontal and flat facing surface 41 facing the shower plate 35 is formed on the outer side of the recess. The recess is circular, and its diameter increases as it goes downward, and a circular upper shower head 42 is provided in a manner protruding downward from the bottom surface of the recess. Therefore, an annular groove is formed along the circumference of the first diffusion space 39 in a manner surrounding the upper shower head 42, and the groove is provided as an annular groove 43. The head of the annular groove 43 becomes more pointed as it goes upward. In addition, the lower portion of the top forming portion 33 forming the facing surface 41, the annular groove 43, and the upper shower head 42 constitute a top 49 (refer to Figure 2 ).

[0041] Next, reference is also made to the longitudinal sectional side view of the upper shower head 42. Figure 2 , as a bottom side stereogram Figure 3 , as a top side stereogram Figure 4 , as a cross-sectional top view Figure 5 The outer side peripheral surface of the annular groove 43 as an annular groove is formed as an inclined surface 44 which is inclined downward from the center side to the peripheral side of the first diffusion space 39. The angle θ1 formed by the inclined surface 44 and the horizontal plane (see Figure 2 ) is, for example, 20° to 50°, more specifically, 30°. The inclined surface 44 guides the gas ejected from the third gas ejection port 53 of the upper shower head 42 described later into the annular groove 43 to the peripheral portion of the first diffusion space 39 to prevent the gas from being retained in the first diffusion space 39.

[0042] The lower part of the upper shower head 42 decreases in diameter as it goes toward the lower end of the upper shower head 42, so that the side surface of the lower part of the upper shower head 42 is formed into an inclined surface 46, and the inclined surface 46 forms the inner side circumferential surface of the above-mentioned annular groove 43. Moreover, the lower surface of the upper shower head 42 is continuous with the inclined surface 46, and is formed into a horizontal facing surface 47 facing the upper surface of the shower plate 35. In the facing surface 47, a large number of second gas ejection ports 51 are respectively punched in a dispersed manner along the vertical direction in the surface. In addition, in order to prevent a large amount of gas from being locally supplied to the wafer W, the second gas ejection port 51 is formed in a manner that does not overlap with the first gas ejection port 38 of the shower plate 35 described above. In addition, the first gas ejection port 38 and the second gas ejection port 51 are formed vertically, which means that they are formed vertically in design, and even if they are tilted by, for example, a few degrees relative to the vertical axis due to, for example, manufacturing errors or assembly errors of the device, they are also formed vertically.

[0043] A circular shallow recess is formed in the central upper part of the upper shower head 42, and the recess is closed from the upper side by the above-mentioned top forming portion 33. As a result, the recess is formed into a circular and flat second diffusion space 52 divided from the surrounding. In addition, when viewed from above, the centers of the upper shower head 42 and the second diffusion space 52 are aligned with the centers of the first diffusion space 39 and the mounting table 21 mentioned above, so that gas can be uniformly supplied to the wafer W. The gases supplied to the upper shower head 42 diffuse in the second diffusion space 52 in the lateral direction. The above-mentioned second gas outlets 51 are connected to the bottom of the second diffusion space 52.

[0044] In addition, a large number of third gas outlets 53 are arranged in a row along the circumferential direction of the first diffusion space 39 on the inclined surface 46 of the upper shower head 42. Each third gas outlet 53 has an opening at the same height position, and the intervals between adjacent third gas outlets 53 are equal to each other. Moreover, each third gas outlet 53 is formed to be inclined relative to the vertical direction in a manner that goes toward the center of the upper shower head 42 as it goes upward, and is connected to the side of the second diffusion space 52. For example, the angle θ2 formed by the opening direction of the third gas outlet 53 relative to the horizontal plane is 30° to 90° (refer to Figure 2 ), more specifically, for example, 45°. Figure 5 As shown, the third gas ejection ports 53 are formed by radially drilling holes in the upper shower head 42 in a plan view, and eject gas radially from the center side of the first diffusion space 39 toward the peripheral side.

[0045] In addition, Figure 2 , the height between the upper surface of the shower plate 35 and the facing surface 47 of the upper shower head 42 is represented as H1. In addition, the height between the upper surface of the shower plate 35 and the facing surface 41 on the outer side of the annular groove 43 is represented as H2. In order to prevent gas from being retained in the first diffusion space 39, these heights H1 and H2 are, for example, the same. Moreover, if the volume of the first diffusion space 39 is small, the time required for purging the TiCl4 gas and the NH3 gas in the first diffusion space 39 can be suppressed, and the length of the ALD cycle described later can be shortened. Therefore, with respect to the heights H1 and H2, for example, it is preferably set to be less than 8 mm, and with respect to the depth H3 of the annular groove 43, for example, it is preferably set to be less than 12 mm.

[0046] in addition, Figure 5 R1 shown is a virtual circle obtained by connecting the centers of the first gas outlets 38 located at the most peripheral position of the shower plate 35. R2 is a virtual circle obtained by connecting the centers of the second gas outlets 51 located at the most peripheral position in the facing surface 47 of the upper shower head 42. R3 represents a circle obtained by connecting the centers of the third gas outlets 53, but is shown in a manner overlapping with the outer edge of the upper shower head 42 in the figure. That is, circles R1, R2, and R3 respectively represent the formation areas of the first gas outlet 38, the second gas outlet 51, and the third gas outlet 53. The centers of the circles R1, R2, and R3 are consistent, and the sizes of the diameters are circle R1>circle R3>circle R2. Therefore, the area where the second gas outlet 51 and the third gas outlet 53 are distributed is smaller than the area where the first gas outlet 38 is distributed. The diameters of the circles R1, R2, and R3 are respectively represented as diameters L1, L2, and L3. L1 is substantially the same as the diameter of the wafer W, for example, 300 mm. L2 / L1 is, for example, 0.3 to 0.4, and L3 / L1 is, for example, 0.35 to 0.45.

[0047] return Figure 1 , and refer to Figure 6 and Figure 7 Next, the gas supply path 6 provided in the gas supply path forming portion 3 for supplying each gas to the second diffusion space 52 of the upper shower head 42 described above is described. The gas supply path 6 is composed of a first dedicated flow path 61, a second dedicated flow path 62, a confluent path 63, two branch paths 64, a third diffusion space 65, eight first connecting flow paths 71, and eight second connecting flow paths 72. The upper sides of the first dedicated flow path 61, the second dedicated flow path 62, the confluent path 63, and the branch paths 64 are provided, for example, in the above-mentioned gas introduction portion 32, and the lower sides of the branch paths 64, the third diffusion space 65, the first connecting flow paths 71, and the second connecting flow paths 72 are provided, for example, in the above-mentioned main body portion 31.

[0048] The first dedicated flow path 61 and the second dedicated flow path 62 are respectively arranged to extend in the horizontal direction, and these first dedicated flow paths 61 and the second dedicated flow paths 62 are divided in an independent manner. The raw material gas, the carrier gas of the raw material gas and the purge gas are supplied to the upstream side of the first dedicated flow path 61, and the reaction gas, the carrier gas of the reaction gas and the purge gas are supplied to the upstream side of the second dedicated flow path 62. Therefore, the first dedicated flow path 61 is a flow path dedicated to the raw material gas among the raw material gas and the reaction gas, and the second dedicated flow path 62 is a flow path dedicated to the reaction gas among the raw material gas and the reaction gas. The first dedicated flow path 61 is located above the second dedicated flow path 62, and the downstream side of the first dedicated flow path 61 is bent downward and connected to the second dedicated flow path 62. As a result, the downstream sides of these first dedicated flow paths 61 and the second dedicated flow paths 62 merge with each other to form the above-mentioned merged flow path 63.

[0049] The downstream side of the confluence path 63 extends horizontally along the extension direction of the second dedicated flow path 62, and then branches to the left and right when viewed in the extension direction, thereby forming the above-mentioned two branch paths 64. The downstream side of each branch path 64 extends in the horizontal direction, bends vertically downward, and is connected to different positions in the flat third diffusion space 65. By branching the downstream side of the confluence path 63 and connecting to the third diffusion space 65 in this way, the gas is distributed in the third diffusion space 65 with high uniformity, and the uniformity of the concentration of each gas in the above-mentioned second diffusion space 52 becomes higher. In addition, the lengths of the branch paths 64 are equal to each other.

[0050] When viewed from above, the third diffusion space 65 is composed of a cross flow path 66 formed by the intersection of a straight introduction path and another straight introduction path, four branch paths 67, and eight branch ends 68. The downstream ends of the branch paths 64 are connected to one end and the other end of a straight flow path constituting the cross flow path 66. The lengths from the center of the cross flow path 66 to the downstream ends of each branch path 64 are equal. The center of the cross flow path 66 is located at the center of the second diffusion space 52. When viewed from the extension direction of the other straight flow paths constituting the cross flow path 66, each end of the other straight flow paths branches to the left and right to form the branch paths 67.

[0051] The upstream side of the branch path 67 extends along a straight lead-in path forming the above-mentioned cross flow path 66. Moreover, the downstream side of the branch path 67 is bent relative to the upstream side and extends in a manner away from the center of the cross flow path 66. When viewed from the elongation direction of the flow path on the downstream side of the branch path 67, the downstream end of the branch path 67 branches to the left and right to form the above-mentioned branch ends 68. When viewed from above, these branch ends 68 are respectively formed to expand their width in a manner extending toward the outside of the center of the cross flow path 66. Moreover, the lower parts of these eight branch ends 68 are respectively connected to the upstream ends of eight first path flow paths 71 as linear flow paths. The lengths from the center of the cross flow path 66 to each first connecting flow path 71 are respectively equal.

[0052] The downstream side of the eight first connecting flow paths 71 is formed to extend radially when viewed from above as it goes obliquely downward, and the downstream end of the first connecting flow path 71 is connected to the peripheral portion of the above-mentioned second diffusion space 52 from above. Each first connecting flow path 71 has the same length as each other. Moreover, a second connecting flow path 72 as a linear flow path extends obliquely downward from the central portion in the length direction of each first connecting flow path 71, and the second connecting flow path 72 is formed to face the central portion side of the second diffusion space 52 when viewed from above. Each second connecting flow path 72 also has the same length as each other. Moreover, the downstream end of each second connecting flow path 72 is connected to a position in the second diffusion space 52 that is closer to the central portion side than the position connecting the first connecting flow path 71 in a manner spaced equally in the circumferential direction. In addition, the first connecting flow path 71 and the second connecting flow path 72 are connected to the second diffusion space 52 from a direction inclined relative to the second diffusion space 52 formed horizontally, and these first connecting flow paths 71 and the second connecting flow paths 72 are configured as inclined flow paths.

[0053] exist Figure 6 In FIG. 1 , the upstream end of the confluent passage 63 is indicated as point P1, that is, the position where the first dedicated passage 61 and the second dedicated passage 62 at the downstream ends of the first dedicated passage 61 and the second dedicated passage 62 merge with each other is indicated as point P1. Figure 2 , the downstream end of the first connecting flow path 71 is indicated as point P2, and the downstream end of the second connecting flow path 72 is indicated as point P3. Points P2 and P3 are also the upper ends of the second diffusion space 52. The lengths of the flow paths from point P1 to each point P2 are equal, and the lengths of the flow paths from point P1 to each point P3 are equal. In addition, the lengths of the flow paths from point P1 to point P2 are equal to the lengths of the flow paths from point P1 to point P3.

[0054] In addition, the case where the lengths of the flow paths are equal to each other includes the case where the flow paths are equal in the design of the device. That is, even if the assembly error of the components constituting the device or the processing accuracy of the components results in different lengths of the flow paths, as long as the design is made in such a way that the lengths of the flow paths are equal, it is also included in the case where the lengths of the flow paths are equal. In addition, with respect to each flow path from the point P1 to each point P2 and P3, the flow path widths at positions at the same distance from the point P1 can be set to the same width, or the concentration distribution of the gas in the second diffusion space 52 can be adjusted by setting the flow path widths to slightly different widths.

[0055] return Figure 1 The description is continued. The upstream ends of the first dedicated flow path 61 and the second dedicated flow path 62 formed in the above-mentioned gas supply path forming portion 3 are connected to the downstream ends of the pipes 81 and 91, respectively. The upstream end of the pipe 81 is connected to the supply source 84A of the TiCl4 gas as the processing gas via the valve V1, the gas storage tank 82A, and the flow adjustment unit 83A in sequence. The flow adjustment unit 83A is composed of a mass flow controller, which is used to adjust the flow rate of the TiCl4 gas supplied from the gas supply source 84A to the downstream side. In addition, the other flow adjustment units 83B to 83F described later are also constructed in the same way as the flow adjustment unit 83A, and are used to adjust the flow rate of the gas supplied to the downstream side of the pipe.

[0056] The gas storage tank 82A forming the gas storage section temporarily stores the TiCl4 gas supplied from the gas supply source 84A before the TiCl4 gas is supplied to the processing container 11. After the TiCl4 gas is stored in this way and the pressure in the gas storage tank 82A is increased to a predetermined pressure, the TiCl4 gas is supplied from the gas storage tank 82A to the gas supply path forming section 3. The supply and cutoff of the TiCl4 gas from the gas storage tank 82A to the gas supply path forming section 3 are performed by opening and closing the above-mentioned valve V1. By temporarily storing the TiCl4 gas in the gas storage tank 82A in this way, the TiCl4 gas can be supplied to the processing container 11 at a relatively high flow rate. In addition, the gas storage tanks 82B, 82D, and 82E forming the gas storage section described later also temporarily store the gases supplied from the gas supply source on the upstream side of the piping in the same manner as the gas storage tank 82A. The supply and cutoff of gas from the gas storage tanks 82B, 82D, 82E to the gas supply path forming portion 3 are performed by opening and closing valves V2, V4, and V5 provided on the downstream side of the gas storage tanks 82B, 82D, and 82E.

[0057] The downstream side of the valve V1 in the above-mentioned piping 81 is connected to the downstream end of the piping 85. The upstream end of the piping 85 is connected to the supply source 84B of N2 gas via the valve V2, the gas storage tank 82B, and the flow rate adjustment unit 83B in sequence. In addition, the downstream side of the valve V2 in the piping 85 is connected to the downstream end of the piping 86. The upstream end of the piping 86 is connected to the supply source 84C of N2 gas via the valve V3 and the flow rate adjustment unit 83C in sequence.

[0058] Next, the piping 91 is described. The upstream end of the piping 91 is connected to the NH3 gas supply source 84D via the valve V4, the gas storage tank 82D, and the flow rate adjustment unit 83D in sequence. The downstream side of the valve V4 in the piping 91 is connected to the downstream end of the piping 92. The upstream end of the piping 92 is connected to the N2 gas supply source 84E via the valve V5, the gas storage tank 82E, and the flow rate adjustment unit 83E in sequence. In addition, the downstream side of the valve V5 in the piping 92 is connected to the downstream end of the piping 93. The upstream end of the piping 93 is connected to the N2 gas supply source 84F via the valve V6 and the flow rate adjustment unit 83F in sequence.

[0059] A throttle hole 87 is formed on the downstream side of the valve V3 in the pipe 86, and a throttle hole 88 is formed on the downstream side of the valve V6 in the pipe 93. These throttle holes 87 and 88 are used to form narrow flow paths in the pipes 86 and 93 to prevent the gases supplied at a relatively large flow rate from the gas storage tank from flowing into the valves V3 and V6.

[0060] In addition, in order to perform the above-mentioned purging, the N2 gas supplied from the above-mentioned N2 gas supply sources 84B and 84E is supplied into the processing container 11. The N2 gas supplied from the N2 gas supply sources 84C and 84F is a carrier gas for the TiCl4 gas and the NH3 gas. As described above, the carrier gas is continuously supplied into the processing container 11 during the processing of the wafer W, and therefore the carrier gas is also supplied into the processing container 11 during the purging. Therefore, the time period for supplying the carrier gas into the processing container 11 overlaps with the time period for supplying the N2 gas from the gas supply sources 84B and 84E into the processing container 11 for purging. The carrier gas is also used for purging, but for the sake of convenience of description, the gas supplied from the N2 gas supply sources 84B and 84E is described as the purging gas, and the gas supplied from the N2 gas supply sources 84C and 84F is described as the carrier gas.

[0061] In addition, the film forming apparatus 1 includes a control unit 10. The control unit 10 is composed of a computer and includes a program, a memory, and a CPU. The program is compiled into a step group so that a series of actions described later in the film forming apparatus 1 can be implemented. The control unit 10 uses the program to output control signals to each part of the film forming apparatus 1 to control the actions of each part. Specifically, the control signals are used to control the opening and closing of each valve V1 to V6, the flow rate adjustment of the gas by the flow adjustment unit 83A to 83F, the pressure adjustment in the processing container 11 by the pressure adjustment mechanism 18, and the temperature adjustment of the wafer W by the heater 22. The above-mentioned program is stored in a storage medium such as a CD, a hard disk, or a DVD, and is installed in the control unit 10.

[0062] Next, referring to the diagram showing the opening and closing states of each valve and the flow state of gas in each pipe, Figure 8 to Figure 10 The film forming process performed by the film forming apparatus 1 is described below. Figure 8 to Figure 10 In FIG. 1 , the closed valve V is indicated by hatching to distinguish it from the open valve V. In addition, regarding the pipes 81, 85, 86, 91 to 93, the portion where the gas flows to the downstream side is indicated thicker than the portion where the gas does not flow to the downstream side. In addition, reference is also made to the timing diagram which shows the time period for supplying each gas. Fig.11 In this timing diagram, the supply period of the carrier gas is indicated by hatching, and the supply period of the purge gas is indicated by dots. In addition, the supply period of the TiCl4 gas and the supply period of the NH3 gas are indicated by mesh patterns, and the mesh representing the supply period of the TiCl4 gas is larger than the mesh representing the supply period of the NH3 gas.

[0063] First, with valves V1 to V6 closed, the wafer W is transported into the processing container 11 by the transport mechanism and placed on the mounting table 21 located at the transfer position. After the transport mechanism is withdrawn from the processing container 11, the gate valve 13 is closed. The wafer W is heated to the temperature described above by the heater 22 of the mounting table 21, and the mounting table 21 is raised to the processing position to form a processing space 37. On the other hand, the processing container 11 is made to have a predetermined vacuum pressure by exhausting gas from the exhaust duct 14.

[0064] Then, valves V3 and V6 are opened, and carrier gas (N2 gas) is supplied from N2 gas supply sources 84C and 84F to gas supply path 6, respectively. On the other hand, TiCl4 gas and NH3 gas are supplied from gas supply source 84A and gas supply source 84D to pipes 81 and 91. By closing valves V1 and V4, these TiCl4 gas and NH3 gas are stored in gas storage tanks 82A and 82D, respectively, so that the pressure in the gas storage tanks 82A and 82D is increased. After that, valve V1 is opened (time t1 in the figure), so that the TiCl4 gas stored in the gas storage tank 82A is supplied to the shower head 42 via the gas supply path 6. Moreover, the TiCl4 gas is ejected vertically downward from the second gas ejection port 51 of the upper shower head 42 and supplied to the central portion of the first diffusion space 39, and is ejected obliquely downward from the third gas ejection port 53 into the annular groove 43. The TiCl4 gas ejected into the annular groove 43 flows along the inclined surface 44 of the annular groove 43 as described above, and thus does not stay in the annular groove 43, but is supplied to the outside of the annular groove 43. Moreover, the upper surface of the shower plate 35 forming the upper and lower parts of the first diffusion space 39 and the facing surface 41 of the gas supply path forming portion 3 are flat, so the TiCl4 gas flowing out of the annular groove 43 can quickly go to the peripheral portion of the first diffusion space 39 in a manner that its flow is not blocked.

[0065] As described above, TiCl4 gas is supplied to each part of the first diffusion space 39, whereby within a short period of time after the supply of the TiCl4 gas begins, the TiCl4 gas is distributed in each part of the first diffusion space 39 with a highly uniform concentration. Furthermore, the TiCl4 gas is supplied to the wafer W from the first gas outlet 38 of the shower plate 35, and the TiCl4 gas is adsorbed on the surface of the wafer W with high uniformity. In parallel with the supply of the TiCl4 gas to the wafer W, a purge gas (N2 gas) is supplied from the gas supply sources 84B and 84E to the pipes 85 and 92, respectively. The purge gas is stored in the gas storage tanks 82B and 82E by closing valves V2 and V5, thereby increasing the pressure in the gas storage tanks 82B and 82E. Figure 8 , step S1).

[0066] After that, the valve V1 is closed and the valves V2 and V5 are opened (at time t2). Thus, the supply of TiCl4 gas into the processing container 11 is stopped, and the purge gas stored in each gas storage tank 82B and 82E is supplied to the gas supply path 6. The purge gas is ejected from the second gas ejection port 51 and the third gas ejection port 53 of the upper shower head 42 to the first diffusion space 39 in the same manner as the TiCl4 gas. Therefore, the purge gas rapidly diffuses in the first diffusion space 39 in the same manner as the TiCl4 gas, and is distributed in the first diffusion space 39 with a high uniformity of concentration, and is ejected from the shower plate 35.

[0067] As a result, the TiCl4 gas remaining in the processing space 37 that is not adsorbed on the wafer W is removed simultaneously or substantially simultaneously from above each portion within the surface of the wafer W, and the adsorption of the TiCl4 gas to the wafer W is stopped. The TiCl4 gas is purged to the exhaust pipe 14 to remove the TiCl4 gas from the processing container 11. The purging is performed in this way, and on the other hand, the valve V1 is closed, so that the TiCl4 gas supplied from the gas supply source 84A to the pipe 81 is stored in the gas storage tank 82A, and the pressure in the gas storage tank 82A is increased ( Fig. 9 , step S2).

[0068] Next, valves V2 and V5 are closed and valve V4 is opened (at time t3). Thus, the supply of purge gas to the gas supply path 6 is stopped, and NH3 gas stored in the gas storage tank 82D is supplied to the gas supply path 6, and the NH3 gas is ejected from the second gas outlet 51 and the third gas outlet 53 of the upper shower head 42 to the first diffusion space 39. The NH3 gas is also distributed in each part of the first diffusion space 39 with high concentration uniformity, similarly to the TiCl4 gas and the purge gas, and is supplied from the shower plate 35 to the processing space 37. Thus, NH3 gas is supplied to each part of the surface of the wafer W with high uniformity. As a result, the TiCl4 gas adsorbed with high uniformity on the surface of the wafer W undergoes a nitridation reaction to form a thin layer of TiN as a reaction product. On the other hand, by closing valves V2 and V5, the purge gas supplied from gas supply sources 84B and 84E to pipes 85 and 92 is stored in gas storage tanks 82B and 82E, respectively, thereby increasing the pressure in the gas storage tanks 82B and 82E ( Fig.10 , step S3).

[0069] After that, valve V4 is closed and valves V2 and V5 are opened, and each valve becomes Fig. 9The same open and closed state (time t4) as step S2 described in the above description is achieved. By becoming such an open and closed state, the supply of NH3 gas into the processing container 11 is stopped, and the purge gas stored in each gas storage tank 82B, 82E is supplied to the gas supply path 6 in the same manner as step S2. Then, the purge gas is sprayed from the upper shower head 42 to the first diffusion space 39, and then sprayed from the shower plate 35. By supplying the purge gas, the unreacted NH3 gas remaining in the processing space 37 is removed from above each portion of the surface of the wafer W simultaneously or substantially simultaneously to stop the nitridation reaction, thereby making the thickness of the thin layer of TiN in each portion of the surface of the wafer W consistent. The NH3 gas removed from above the wafer W is purged into the exhaust duct 14 to remove the NH3 gas from the processing container 11. While the purge is performed in this manner, the valve V4 is closed, thereby storing the NH 3 gas supplied from the gas supply source 84D to the pipe 91 in the gas storage tank 82D, thereby increasing the pressure in the gas storage tank 82D (step S4 ).

[0070] After a specified time has passed since time t4, valves V2 and V5 are closed and valve V1 is opened (time t5), the supply of purge gas into the processing container 11 is stopped, and TiCl4 stored in the gas storage tank 82A is supplied to the gas supply path 6. That is, the above-mentioned step S1 is performed again. Therefore, the time t5 when the above-mentioned purge ends is also the time t1 when the supply of the above-mentioned TiCl4 gas starts. After performing this step S1, the above-mentioned steps S2 to S4 are performed, and then steps S1 to S4 are performed again. That is, when the above-mentioned steps S1 to S4 are set as a cycle, the cycle is repeated so that a thin layer of TiN is deposited on the surface of the wafer W to form a TiN film. Moreover, after the cycle is executed a specified number of times, the wafer W is moved out of the processing container 11 in a process opposite to the process when the wafer W is moved into the processing container 11.

[0071] According to the film forming apparatus 1, an upper shower head 42 is provided for supplying gas from above the center of the first diffusion space 39 formed above the shower plate 35. The upper shower head 42 includes a second gas ejection port 51 opened vertically and a third gas ejection port 53 opened in a row in the circumferential direction of the first diffusion space 39 in a manner inclined toward the outside of the facing surface 47 forming the second gas ejection port 51. Gas is supplied to the center of the first diffusion space 39 by means of the second gas ejection port 51. On the other hand, a sufficient amount of gas is also quickly supplied to the peripheral portion of the first diffusion space 39 by means of the third gas ejection port 53. Therefore, each gas can be distributed in the first diffusion space 39 with high uniformity. As a result, gas can be supplied from the shower plate 35 to each portion within the surface of the wafer W with high uniformity of concentration, so that a TiN film can be formed within the surface of the wafer W with high uniformity of film thickness. In addition, the third gas ejection port 53 has an opening on the side surface of the center portion of the annular groove 43 as a concave portion near the first diffusion space 39, and the side surface of the annular groove 43 near the peripheral portion of the first diffusion space 39 forms an inclined surface 44 that descends toward the peripheral portion. Therefore, the gas ejected from the third gas ejection port 53 is suppressed from being retained in the annular groove 43, and a TiN film can be formed more reliably in the surface of the wafer W in a manner having a highly uniform film thickness.

[0072] In addition, when the wafer W is heated to a relatively high temperature of 400°C to 700°C for processing, in order to improve the uniformity of the film thickness of the wafer W in the plane and improve the coverage of the TiN film in each part of the surface of the wafer W, it is preferable to make the supply flow rate of the raw material gas relatively large. The gas storage tanks 82B and 82E described above are provided so that even if the raw material gas is supplied at a relatively large flow rate, the raw material gas can be purged in a short time by supplying a relatively large flow rate of purge gas to the gas supply path forming portion 3. In the case where each gas is supplied to the first diffusion space 39 at a relatively large flow rate, it can be considered that when the flow of the gas in the first diffusion space 39 is blocked, the concentration distribution of the gas in each part of the surface of the wafer is likely to be different. However, as also shown in the evaluation test described later, according to the structure of the above-mentioned film forming device 1, it is possible to prevent the gas from being stagnant in the first diffusion space 39, so that the surface of the wafer W can be processed with high uniformity. However, even when the gas is supplied without passing through the gas storage tanks, by supplying the gas using the upper shower head 42 as described above, it is possible to prevent the gas from stagnating in the first diffusion space 39, thereby enabling highly uniform processing within the surface of the wafer W. That is, the film forming apparatus 1 may be configured not to have the gas storage tanks.

[0073] In addition, the first connecting flow path 71 extending from the third diffusion space 65 is connected to the peripheral portion of the second diffusion space 52 from an oblique direction, thereby making the length of the gas flow path from the point P1 where the first dedicated flow path 61 and the second dedicated flow path 62 merge to the second diffusion space 52 consistent with each other. With such a structure, each gas can be supplied to each portion of the peripheral direction of the second diffusion space 52 with a high uniformity concentration, and each portion of the peripheral edge of the wafer W can be more reliably processed with high uniformity. In addition, by forming the second connecting flow path 72 branching from the first connecting flow path 71 and extending in an oblique direction, the length of the flow path from the above-mentioned point P1 to the point P2 of the peripheral portion of the second diffusion space 52 is made consistent with the length of the flow path from the point P1 to the point P3 near the center of the second diffusion space 52. With such a structure, gas is supplied to the center and the peripheral portion of the second diffusion space 52 with high uniformity, and the center and the peripheral portion of the wafer W can be more reliably processed with high uniformity.

[0074] In addition, in the above-mentioned embodiment, it is possible to have a structure in which the annular groove 43 is not provided on the lower surface of the top 49, or it is possible to have a structure in which the lower surface is provided as a flat surface and the second gas outlet 51 and the third gas outlet 53 are provided on the flat top surface. However, by providing the annular groove 43 as described above to guide the flow of the gas from the third gas outlet 53, it is possible to more reliably make the gas concentration in each part of the first diffusion space 39 uniform, and therefore it is preferred.

[0075] The shape of the inclined surface 44 of the annular groove 43 observed in a longitudinal section is not limited to a straight line, and may also be a curve. In addition, as for the annular groove 43, as long as the gas ejected from the third gas ejection port 53 can be guided in this way, it can also be divided in the circumferential direction. That is, recesses are formed at intervals in the circumferential direction. Moreover, each recess may also be configured as follows: the third gas ejection port 53 has an opening on the side of the central portion side of the first diffusion space 39, and the side of the peripheral portion side of the first diffusion space 39 forms an inclined surface. However, with respect to the recess having the third gas ejection port 53, by forming the annular groove 43 as described above, the ejected gas can flow radially in the annular groove 43. Thus, the uniformity of the gas in the radial direction in the first diffusion space 39 can be further improved, so it is preferred. In addition, in the above-mentioned example, the upstream side of the third gas ejection port 53 is connected to the side of the second diffusion space 52, but it may also be connected to the bottom of the second diffusion space 52.

[0076] As an embodiment, a film forming apparatus for performing ALD is shown, but the present invention can also be applied to a film forming apparatus for performing CVD, and in this case, a process gas can be supplied to each portion within the surface of the wafer W with high uniformity to perform film forming processing. In addition, the type of gas used is not limited to the above-mentioned example. Furthermore, the apparatus disclosed in the present invention is not limited to application to a film forming apparatus, but can also be applied to an etching apparatus for supplying a process gas to the wafer W for etching. In addition, the embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The above-mentioned embodiments can be omitted, replaced, and changed in various ways as long as they do not depart from the attached claims and their subject matter.

[0077] Evaluation test

[0078] Next, the evaluation test performed in association with the film forming apparatus 1 is described. As an evaluation test 1, the film forming apparatus 1 is used to perform film forming processing on the wafer W, and the distribution of the film thickness of each part within the surface of the wafer W is investigated. In addition, the average value of the formed film thickness and the range of the film thickness (maximum value of the film thickness - minimum value of the film thickness) are calculated. As a comparative test 1, the same test as the test of the film forming apparatus 1 is performed using the experimental film forming apparatus. The difference between the experimental film forming apparatus and the film forming apparatus 1 is described. In the experimental film forming apparatus 1, no annular groove 43 is provided on the top surface for defining the first diffusion space 39, and a circular gas ejection portion is provided in a manner protruding downward from the top surface. The gas ejection portion is provided in plurality at intervals in the circumferential direction of the first diffusion space 39. In addition, on the side surface of the gas ejection portion, a plurality of gas ejection ports are provided at intervals in the circumferential direction of the gas ejection portion. The gas ejection port of the gas ejection portion has a horizontal opening, and the gas ejection portion ejects gas radially when viewed from above.

[0079] Fig.12 2 is a top view of wafer W showing the results of evaluation test 1. Fig.13 FIG. 1 is a top view of wafer W showing the results of comparative test 1. Fig.12 , Fig.13 In FIG. 1 , the film thickness distribution in the surface of the wafer W is represented by contour lines. Fig.13 In the comparison test 1, the points at the specified film thickness are connected by solid lines, dashed lines, and dotted lines, and the film thickness on each line is different. In the comparative test 1, the area surrounded by the dashed line appears corresponding to the position of the gas ejection part. This is considered to be because: in the first diffusion space 39, the gas is more difficult to flow in the area below the gas ejection part than in other areas. In the evaluation test 1, there is no area where the film thickness is represented by the dashed line or the dotted line, so only the solid line contour is shown. This is considered to be because: the retention of gas in the first diffusion space 39 is suppressed, and the gas flows smoothly. In the evaluation test 1, the average value of the film thickness is The film thickness range is In Comparative Test 1, the average film thickness is The film thickness range is Thus, the average film thickness does not differ greatly, and the film thickness range in Evaluation Test 1 is smaller than that in Comparative Test 1. Therefore, the results of Evaluation Test 1 confirm that the uniformity of film thickness distribution of wafer W can be improved by processing using the film forming apparatus 1 .

Claims

1. A gas processing device, comprising: a vacuum container, wherein a vacuum atmosphere is formed inside the vacuum container; A mounting table, which is arranged in the vacuum container and is used to mount a substrate; a shower plate facing the mounting table and comprising a plurality of first gas ejection ports for ejecting a processing gas in a shower shape toward the substrate for gas treatment; A top portion, which is arranged above the shower plate, and comprises an upper shower head, an annular groove, and a facing surface, wherein the annular groove surrounds the upper shower head, a portion of the annular groove is defined by an inclined surface, the facing surface extends from an outer edge of the inclined surface, and the facing surface is horizontal and flat relative to the shower plate; The first diffusion space of the processing gas is provided between the shower plate and the top in a manner of being connected to each of the first gas ejection ports; a plurality of second gas ejection ports, the plurality of second gas ejection ports being vertically formed on the upper shower head for supplying the processing gas in a spraying manner to the central portion of the first diffusion space; A second diffusion space for the processing gas is provided above the top portion in communication with each of the second gas ejection ports; a gas supply path, which is disposed on the upstream side of the second diffusion space and is used to supply the processing gas to the second diffusion space; as well as a plurality of third gas ejection ports, wherein the plurality of third gas ejection ports are formed on the inclined surface of the upper shower head; Each of the plurality of third gas ejection ports extends from the second diffusion space, and each third gas ejection port is provided in the annular groove in an oblique direction with respect to the vertical axis that is greater than the inclination of the second gas ejection port with respect to the vertical axis. The third gas ejection ports of the plurality of third gas ejection ports are arranged in a row along the circumferential direction of the first diffusion space and communicate with the second diffusion space. Each of the plurality of third gas ejection ports is configured to eject the processing gas radially from a central portion side to a peripheral portion side of the first diffusion space.

2. The gas processing device according to claim 1, characterized in that: The plurality of first gas ejection ports and the plurality of second gas ejection ports are formed so as not to overlap with each other.

3. The gas processing device according to claim 1, characterized in that: The angle of the inclined surface of the top portion is in a range of 20° to 50° relative to a horizontal plane of the top portion.

4. The gas processing device according to claim 1, characterized in that: The plurality of third gas ejection ports have openings at the same height position, and intervals between adjacent third gas ejection ports are equal to each other.

5. The gas processing device according to claim 1, characterized in that: An angle of the plurality of third gas ejection ports is in a range of 30° to 90° relative to a horizontal plane of the upper shower head.

6. The gas processing device according to claim 1, characterized in that: The height between the upper surface of the shower plate and the facing surface of the upper shower head is the same as the height between the upper surface of the shower plate and the facing surface of the top.

7. The gas processing device according to claim 6, characterized in that: The height between the upper surface of the shower plate and the facing surface of the upper shower head is 8 mm or less.

8. The gas processing device according to claim 1, characterized in that: When the circle obtained by connecting the centers of the multiple first gas outlets located closest to the periphery of the shower plate is denoted as R1, the circle obtained by connecting the centers of the multiple second gas outlets located closest to the periphery of the upper shower head is denoted as R2, and the circle obtained by connecting the centers of the multiple third gas outlets is denoted as R3, the diameters of R1, R2, and R3 are R1>R3>R2.

9. The gas processing device according to claim 1, characterized in that: When the diameter of the circle obtained by connecting the centers of the multiple first gas outlets located at the most peripheral positions of the shower plate is set as L1, the diameter of the circle obtained by connecting the centers of the multiple second gas outlets located at the most peripheral positions of the upper shower head is set as L2, and the diameter of the circle obtained by connecting the centers of the multiple third gas outlets is set as L3, L2 / L1 is 0.3~0.4, and L3 / L1 is 0.35~0.

45.

10. The gas processing device according to claim 1, characterized in that: The gas supply path includes a plurality of inclined flow paths connected to the second diffusion space from a direction inclined with respect to the second diffusion space.

11. The gas processing device according to claim 10, characterized in that: The inclined flow path comprises: a first connecting flow path formed from the central portion side of the second diffusion space toward the peripheral portion side in a plan view and connected to the second diffusion space; as well as The second connecting flow path branches off from the first connecting flow path and is formed from the peripheral portion side toward the central portion side of the second diffusion space in a plan view to connect to a position in the second diffusion space closer to the central portion than a position connected to the first connecting flow path.

12. The gas processing device according to claim 1, characterized in that: The process gas includes a first process gas and a second process gas, The gas supply path comprises: A first dedicated flow path that supplies only the first process gas of the first process gas and the second process gas; a second dedicated flow path, which supplies only the second process gas of the first process gas and the second process gas; a merging passage formed by merging a downstream side of the first dedicated passage and a downstream side of the second dedicated passage; as well as A branch path is formed by branching the downstream side of the merged path to form a plurality of branch paths, and the branch paths are used to introduce the first processing gas and the second processing gas into the second diffusion space respectively.

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