Film formation apparatus, film formation method, and substrate support member

Abstract

To prevent occurrence of a problem in processing a subsequent substrate due to film residue after processing when performing a film formation process on a substrate.SOLUTION: Provided is a film formation apparatus including a processing container, a first gas supply portion configured to supply a film formation gas into the processing container to form a film on a substrate placed on a stage, a second gas supply portion configured to supply a cleaning gas that removes a film formed inside the processing container by the film formation gas in a state in which the substrate is not accommodated in the processing container, a through-hole formed in the stage in a vertical direction, a rod-shaped substrate support member provided in the through-hole to support the substrate and extending in the vertical direction, a height changing mechanism configured to change a relative height of the stage and the substrate support member to switch between a state in which the substrate is supported by the stage and a state in which the substrate is supported by the substrate support member, and a groove formed on a side surface of the substrate support member and constituting a flow path of the cleaning gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a film formation apparatus, a film formation method, and a substrate support member. [Background technology]

[0002] In manufacturing semiconductor devices, various films are formed by supplying gas to a substrate such as a semiconductor wafer (hereinafter referred to as a wafer) placed on a stage inside a processing chamber under vacuum pressure. The apparatus for forming such films may be configured to include a substrate support member for supporting and raising and lowering the substrate relative to the upper surface of the stage, in order to transfer the substrate between the stage and a transfer mechanism that transports the substrate inside and outside the processing chamber.

[0003] Patent Document 1 discloses that the lift pins, which are the substrate support members described above, are configured with a notch cut out at the lower side of the enlarged upper end. When the processing chamber is evacuated, gas that accumulates between the substrate and the upper surface of the stage flows through the notch and through the through-holes in the stage through which the lift pins are inserted, and is removed, preventing the substrate from slipping on the stage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-165658 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can prevent problems that occur in processing a subsequent substrate due to film residue after a film formation process on the substrate. [Means for solving the problem]

[0006] The film forming apparatus according to the present disclosure includes a processing chamber having an evacuated atmosphere and a stage for placing a substrate thereon; a first gas supply unit that supplies a film formation gas into the processing chamber in order to form a film on the substrate placed on the stage; a second gas supply unit that supplies a cleaning gas that removes a film formed in the processing vessel by the film forming gas when the substrate is not stored in the processing vessel; a through hole formed in the stage in a vertical direction; a substrate support member disposed in the through hole and extending in a vertical direction to support the substrate; a height changing mechanism that changes the relative height between the stage and the substrate support member so that the substrate can be switched between a state in which the substrate is supported by the stage and a state in which the substrate is supported by the substrate support member; a groove formed on a side surface of the substrate support member and forming a flow path for the cleaning gas; Equipped with. [Effects of the Invention]

[0007] The present disclosure can prevent problems from occurring in the processing of subsequent substrates due to film residue after processing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional side view of a film forming apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a plan view of a stage in the film forming apparatus. [Figure 3] FIG. 2 is a perspective view of a lift pin provided on the stage. [Figure 4] FIG. 2 is a cross-sectional plan view of the lift pin. [Figure 5] FIG. 3 is a schematic diagram showing a gas flow during a cleaning process in the film forming apparatus. [Figure 6] 5A to 5C are process diagrams showing the operation of lift pins in the film forming apparatus. [Figure 7]FIG. 3 is a schematic diagram showing a gas flow during a cleaning process in the film forming apparatus. [Figure 8] 10A to 10C are process diagrams showing the operation of the lift pin in a comparative example. [Figure 9] FIG. 2 is a schematic diagram showing the gas flow around the lift pin. [Figure 10] FIG. 10 is a side view showing another example of the configuration of the lift pin. [Figure 11] FIG. 10 is a vertical cross-sectional side view of the film forming apparatus 1 equipped with lift pins having another configuration. [Figure 12] FIG. 10 is a schematic diagram showing the results of an evaluation test. [Figure 13] FIG. 10 is a schematic diagram showing the results of a comparison test. DETAILED DESCRIPTION OF THE INVENTION

[0009] A film formation apparatus 1 according to an embodiment of the present disclosure will be described with reference to the longitudinal side view of FIG. 1 . The film formation apparatus 1 includes a processing chamber 11, the interior of which is evacuated to a vacuum pressure. Wafers W are stored in the processing chamber 11, and a film formation gas is supplied to form a film on the wafer W. In this example, a TiN (titanium nitride) film is formed by ALD. After this film formation process is repeated, for example, a predetermined number of times to form films on multiple wafers W, a cleaning process is performed in which a cleaning gas is supplied into the processing chamber 11 without the wafers W stored therein. This removes the TiN film formed in various parts of the processing chamber 11 during film formation on the wafers W.

[0010] The processing vessel 11 is circular in plan view. A loading / unloading port 12 for the wafer W and a gate valve 13 for opening and closing the loading / unloading port 12 are provided on a sidewall of the processing vessel 11. An exhaust duct 14, which is rectangular in vertical cross section and annular in plan view, is provided above the loading / unloading port 12, and the exhaust duct 14 forms a part of the processing vessel 11. An exhaust port 15 opens in the sidewall on the inner periphery of the exhaust duct 14 along the circumferential direction of the exhaust duct 14. Therefore, the exhaust port 15 is formed in the sidewall of the processing vessel 11, and in plan view, the exhaust port 15 is annular in shape so as to surround a stage 21, which will be described later.

[0011] An exhaust mechanism 16 is connected to the exhaust duct 14. The exhaust mechanism 16 includes a valve disposed in an exhaust path and a vacuum pump that exhausts the interior of the processing vessel 11 through the exhaust path, and the amount of gas exhausted from the exhaust port 15 is adjusted by adjusting the opening of the valve using a control unit 100 (described later), thereby forming a vacuum atmosphere of a desired pressure inside the processing vessel 11. In the drawing, reference numeral 14A denotes a flow restriction member provided on the inner periphery of the exhaust duct for restricting the flow of gas during film formation processing.

[0012] 2, the stage 21 provided in the processing vessel 11 will be described. As shown in the figure, the stage 21 is circular in plan view. A portion of the upper side of the stage 21 is recessed, forming a circular recess 22. Three recesses 22 are provided on the periphery of the stage 21, and are spaced apart from one another along the circumferential direction of the stage 21.

[0013] The bottom surface of each recess 22 forms a pin support surface 23 that supports lift pins 6, which will be described later, and is formed as a horizontal surface. The upper surface of the stage 21 outside the recess 22 is formed as a wafer support surface 24. The wafer support surface 24 is also formed as a horizontal surface, and the wafer W is placed horizontally on this wafer support surface 24. As described above, the pin support surface 23 and the wafer support surface 24 each form a part of the upper surface of the stage 21. It should be noted that the wafer support surface 24 occupies most of the upper surface of the stage 21.

[0014] As shown in FIG. 1 , through-holes 25 extending in the vertical direction are formed in the stage 21. The upper and lower ends of the through-holes 25 open to the pin support surface 23 and the underside of the stage 21, respectively. A through-hole 25 is provided for each recess 22. Therefore, although only two through-holes 25 are shown in FIG. 1 , a total of three through-holes 25 are provided. In plan view, the through-holes 25 are circular. Furthermore, the diameter of the through-holes 25 is smaller than the diameter of the recesses 22 in plan view, and the centers of the recesses 22 and the through-holes 25 are aligned. Therefore, it can be said that the recesses 22 are formed by enlarging the upper side of the through-holes formed in the stage 21. Lift pins 6 are provided in the through-holes 25, which will be described in detail later. The peripheral surface of the through-holes 25 is shown as the hole wall surface 20.

[0015] A heater 26 is embedded in the stage 21, and heats the wafer W placed on the wafer support surface 24 to a predetermined temperature. The central lower portion of the stage 21 is supported by the upper ends of support columns 27, the lower ends of which penetrate the bottom of the processing vessel 11 and are connected to an elevator mechanism 28 provided outside the processing vessel 11. The elevator mechanism 28 raises and lowers the stage 21 between a standby position at the lower side within the processing vessel 11, shown by the dashed line in FIG. 1, and a processing position at the upper side within the processing vessel 11, shown by the solid line in FIG. 1.

[0016] The standby position is a position where the stage 21 waits to transfer the wafer W between the stage 21 and the transfer mechanism 10 that is entering the processing vessel 11 through the loading / unloading port 12. The transfer mechanism 10 is not shown in FIGS. 1 and 2. The processing position is a position where the wafer W is processed. Note that 29 in FIG. 1 is a cover that surrounds the side of the stage 21, which faces the flow regulating member 14A when the stage 21 is located at the processing position and, together with the flow regulating member 14A, prevents gas from flowing around to the underside of the stage 21.

[0017] 1, reference numeral 31 denotes a flange, which is attached to support column 27 and located below the bottom of processing vessel 11. Bellows 32, which is expandable and contractible, is provided to surround support column 27. Bellows 32 is connected to the bottom of processing vessel 11 and flange 31, respectively, to ensure airtightness inside processing vessel 11.

[0018] A support base 33 is provided below the stage 21, and the aforementioned support columns 27 penetrate this support base 33. The support base 33 is supported by the upper ends of support columns 34, the lower ends of which penetrate the bottom of the processing vessel 11 and are connected to an elevating mechanism 35 provided outside the processing vessel 11. The support base 33 is raised and lowered by the elevating mechanism 35, and when three lift pins 6 (described later) are supported by the support base 33, these lift pins 6 rise and lower collectively. A bellows 36 is provided to surround the support columns 34 and is flexible. The bellows 36 is connected to the bottom of the processing vessel 11 and the elevating mechanism 35 so as to ensure airtightness within the processing vessel 11.

[0019] Gas supply ports 41 and 42 are open at the bottom of the processing vessel 11. An inert gas supply mechanism 43 and a cleaning gas supply mechanism 44 are connected to the gas supply ports 41 and 42 via gas supply pipes, respectively. The cleaning gas supply mechanism corresponds to a second gas supply unit. An inert gas and a cleaning gas are supplied into the processing vessel 11 from the inert gas supply mechanism 43 and the cleaning gas supply mechanism 44 via the gas supply ports 41 and 42, respectively.

[0020] Specifically, this inert gas is, for example, N2 gas, and is supplied during the film formation process and cleaning process to adjust the partial pressure of the cleaning gas in the processing vessel 11 during the cleaning process and to prevent the film formation gas from flowing into the lower side of the stage 21 during the film formation process. The cleaning gas is, for example, ClF3 gas, and is supplied from a gas supply port 42 at a predetermined stage in the cleaning process, as will be described later. Each gas supplied from these gas supply ports 41 and 42 is exhausted to the exhaust port 15 of the exhaust duct 14, and flows upward within the processing vessel 11, then flows into the exhaust port 15 and is removed.

[0021] A top plate 51 is provided above exhaust duct 14 to close processing vessel 11 from above, and a shower head 52 that is circular in plan view is provided on the underside of top plate 51. Shower head 52 includes a gas diffusion space 53 provided therein and a large number of outlet holes 54 provided on the underside, and each outlet hole 54 communicates with gas diffusion space 53 and is formed facing stage 21. In addition, a circular protrusion 56 that protrudes downward is provided on the peripheral edge of shower head 52 to regulate the flow of gas.

[0022] When the stage 21 is positioned at the processing position, the annular protrusion 56 is close to the upper surface of the cover 29 of the stage 21, and the area surrounded by the stage 21, the annular protrusion 56, and the shower head 52 constitutes a processing space 50. The discharge holes 54 open into this processing space 50, and gas is supplied to the wafer W positioned in the processing space 50 during film formation processing. When the stage 21 is positioned at the processing position in this manner, the exhaust port 15 is located to the side of the annular gap formed between the annular protrusion 56 and the cover 29, and the gas supplied to the processing space 50 flows laterally to the outside of the processing space 50 and flows into the exhaust port 15 to be removed.

[0023] A gas supply mechanism 57 is connected to the top plate 51. Gas supplied from the gas supply mechanism 57 is supplied to the gas diffusion space 53 via flow paths formed on the top plate 51 and the upper side of the shower head 52 and then discharged from the discharge holes 54. The gases supplied from the gas supply mechanism 57 include a film-forming gas, an inert gas, and a cleaning gas. The film-forming gas is a gas for forming the TiN film on the wafer W, such as TiCl4 gas and NH3 gas. The inert gas is, for example, N2 gas, and is supplied to purge the processing space 50 when performing film formation by ALD and to adjust the partial pressure of the cleaning gas in the processing chamber 11 during the cleaning process. The cleaning gas is, for example, ClF3 gas, the same as the gas supplied from the gas supply port 42.

[0024] The gas supply mechanism 57 corresponds to the first gas supply unit. Each of the gas supply mechanism 57 and the above-described gas supply mechanisms 43 and 44 includes a gas supply source for storing gas, a valve disposed in a flow path from the gas supply source to the processing vessel 11, and a flow rate adjusting unit such as a mass flow controller for adjusting the flow rate of gas supplied downstream of the flow path.

[0025] Next, the lift pins 6 provided on the stage 21 will be described with reference to the perspective view of Fig. 3 and the cross-sectional plan view of Fig. 4. The lift pins 6 are substrate support members that transport the wafer W between the transport mechanism 10 and the stage 21, and are provided for each through-hole 25 and can be raised and lowered relative to the stage 21. To suppress thermal expansion, the lift pins 6 are made of, for example, ceramics, more specifically, alumina ceramics.

[0026] The lift pin 6 will be described in more detail. The lift pin 6 is a rod-shaped member that extends longitudinally, more specifically, vertically, and includes a shaft 61 and a head 62 provided above the shaft 61. The shaft 61 and the head 62 are each circular when viewed in the extension direction of the lift pin 6 (i.e., the vertical direction), and their central axes are aligned with each other. As will be described later, the diameter of the head 62 is larger than the diameter of the shaft 61 when viewed in the extension direction of the lift pin 6 so that the through-hole 25 can be blocked during a film formation process. Therefore, the area of ​​the head 62 is larger than the area of ​​the shaft 61 when viewed in the extension direction.

[0027] The diameter of the shaft portion 61 is formed slightly smaller than the diameter of the through-hole 25 of the stage 21, and the shaft portion 61 is inserted into the through-hole 25 of the stage 21. The diameter of the head portion 62 is slightly smaller than the diameter of the recess 22 of the stage 21. When the stage 21 is located in the processing position, the lower end of the lift pin 6 (the lower end of the shaft portion 61) is separated from the support base 33, and the head portion 62 is housed within the recess 22 and is supported by the pin support surface 23 of the recess 22, thereby blocking the through-hole 25 from above.

[0028] When the stage 21 is in the standby position, as shown in FIG. 5, the lower ends of the lift pins 6 contact the support base 33, and the heads 62 of the lift pins 6 protrude from the recesses 22 and are positioned above the wafer support surface 24. Because the lift pins 6 contact the support base 33 in this manner, the lift pins 6 rise and fall as the support base 33 is raised and lowered by the lifting mechanism 35, changing their height relative to the stage 21. Furthermore, when the lift pins 6 are supported by the support base 33 in this manner, the height positions of the lift pins 6 relative to the stage 21 also change when the stage 21 is raised and lowered by the lifting mechanism 28. Therefore, the lifting mechanisms 28 and 35 function as a height changing mechanism that changes the relative height between the stage 21 and the lift pins 6. This change in relative height switches between a state in which the wafer W is supported on the wafer support surface 24 and a state in which the wafer W is supported by the lift pins 6 while floating above the wafer support surface 24. Note that FIG. 5 shows the position of the lift pins 6 when a cleaning gas is supplied from the gas supply port 42 and a cleaning process is performed; this cleaning process will be described in detail later.

[0029] The shaft portion 61 is provided with grooves 63 extending in the extension direction of the shaft portion 61 from the upper end to the lower end. Four grooves 63 are provided, which are spaced apart from each other when viewed in the extension direction and are equally spaced around the circumference of the shaft portion 61. In this example, as shown in FIG. 4 , the side and bottom surfaces of the grooves 63 are formed so as to be perpendicular to each other. As described above, the shaft portion 61 is provided inside the through hole 25, and therefore the grooves 63 are positioned opposite the hole wall surface 20 of the through hole 25. As will be described in detail later, each groove 63 forms a flow path for the cleaning gas when the cleaning gas is supplied from the gas supply port 42 to perform cleaning.

[0030] Returning to FIG. 1 , the film forming apparatus 1 includes a control unit 100, which is a computer. The control unit 100 includes a program. The program includes instructions (steps) for transferring the wafer W to and from the transfer mechanism 10, for performing a film forming process on the wafer W, and for performing a cleaning process. The program is stored on a storage medium, such as a compact disc, a hard disk, or a DVD, and is installed in the control unit 100. The control unit 100 outputs control signals to each component of the film forming apparatus 1 based on the program, thereby controlling the operation of each component. Specifically, the control unit 100 controls the opening and closing of the gate valve 13, the raising and lowering of the stage 21 and the support table 33 by the lifting mechanisms 28 and 35, the supply of gases into the processing chamber 11 from the gas supply mechanisms 43, 44, and 57, the temperature of the heater 26, the operation of the exhaust mechanism 16, and the like.

[0031] Next, the loading of the wafer W into the film formation apparatus 1 and the film formation process for the wafer W will be described with reference to the process diagram of Fig. 6 showing the operation of the stage 21 and the lift pins 6 and the schematic diagram of the film formation apparatus 1 in Fig. 7. In Fig. 7, the flow of gas formed inside the processing vessel 11 is indicated by arrows.

[0032] First, with the stage 21 positioned at the standby position and the upper sides of the lift pins 6, including their heads 62, protruding upward from the recesses 22 of the stage 21, the transfer mechanism 10 supporting the wafer W enters the processing chamber 11 through the loading / unloading port 12 and positions itself above the stage 21 (left end of FIG. 6). The support base 33 rises to push up the lift pins 6, and the lift pins 6 support the wafer W instead of the transfer mechanism 10 (second from the left in FIG. 6). The transfer mechanism 10 retreats to the outside of the processing chamber 11, the loading / unloading port 12 is closed, and the stage 21 rises. As the stage 21 rises, the heads 62 of the lift pins 6 approach the stage 21. Then, the stage 21 comes to a standstill at a position where the wafer support surface 24 is close to the wafer W (preheating position), and the wafer W is heated by radiant heat from the stage 21 (center of FIG. 6).

[0033] Thereafter, the stage 21 resumes rising. As a result, the wafer W is placed on the wafer support surface 24, further increasing its temperature, while the heads 62 of the lift pins 6 are stored in the recesses 22 of the stage 21 (second from the right in FIG. 6). The stage 21 then rises further, and the pin support surface 23 of the recesses 22 supports the lift pins 6 instead of the support base 33, and the lift pins 6 move away from the support base 33. Thereafter, the stage 21 reaches the processing position and stops rising (right end in FIG. 6).

[0034] Next, TiCl4 gas, purge gas (inert gas), NH3 gas, and purge gas are supplied to the processing space 50 in this order, and this series of gas supplies is repeated as one cycle to form a TiN film on the wafers W. FIG. 7 shows the flow of gases during the film formation process using arrows. After the above cycle is repeated a predetermined number of times and the film formation process is completed, the reverse operation of the operation performed when the wafers W were loaded into the processing chamber 11 as described in FIG. 6 is performed, and the wafers W on which the film has been formed are unloaded from the processing chamber 11. This process of loading the wafers W into the processing chamber 11, performing the film formation process, and unloading them from the processing chamber 11 is repeated. As described above, after the film formation process has been performed on a predetermined number of wafers W, a cleaning process is performed.

[0035] During the film formation process, the through-hole 25 is blocked by the head 62 of the lift pin 6 as described above. However, trace amounts of film formation gas (TiCl4 gas and NH3 gas) may flow into the through-hole 25 through a small gap between the head 62 and the pin support surface 23 of the recess 22, potentially depositing a film on the side surface of the shaft 61 of the lift pin 6. The film 60 formed on the shaft 61 grows as the film formation process is repeated on the wafer W. The lift pin 6 of the film formation apparatus 1 is configured so that the film 60 is reliably removed during the cleaning process, preventing problems caused by the film 60 remaining.

[0036] Before describing in detail the cleaning process and the advantages of the configuration of the lift pins 6 during the cleaning process, the operation of the film formation apparatus 1A of the comparative example will be described. This film formation apparatus 1A has the same configuration as the film formation apparatus 1, except that lift pins 6A are provided instead of lift pins 6. Lift pins 6A have the same configuration as lift pins 6, except that grooves 63 are not provided.

[0037] Because the gap between the shaft 61 of the lift pin 6A and the wall surface 20 of the through-hole 25 is relatively small, it is difficult for cleaning gas to pass through. As a result, even if a cleaning process is performed, the film 60 may not be sufficiently removed, and may remain after the cleaning process. Then, as the film formation process is repeated after the cleaning process, the film 60 grows. Figure 8 shows a state of the lift pin 6A that may occur when the wafer W is transferred from the transfer mechanism 10 to the stage 21 and the stage 21 is moved to the processing position in a state where the film 60 has grown.

[0038] As explained in FIG. 6, after the wafer W is transferred from the transfer mechanism 10 to the lift pins 6A (left end and second from the left in FIG. 8), the stage 21 rises from the standby position and stops at the preheating position where the wafer support surface 24 is close to the wafer W (center in FIG. 8). For example, when the stage 21 rises, the side of the shaft 61 comes into contact with the hole wall surface 20. The formation of the film 60 increases the friction between the side of the shaft 61 and the hole wall surface 20, so that the shaft 61 is supported by the hole wall surface 20. In other words, the lift pins 6A become caught on the hole wall surface 20 and are prevented from descending relative to the stage 21.

[0039] Thereafter, as the stage 21 rises from the preheating position to the processing position, the lift pins 6A continue to be caught, so that even when the support base 33 moves away from the lift pins 6A, the heads 62 of the lift pins 6A are not stored in the recesses 22 and continue to protrude above the wafer support surface 24 (second from the right in FIG. 8). Therefore, the heads 62 continue to support the wafer W, and the portion of the wafer W supported by the heads 62 and the surrounding portion are not placed on the wafer support surface 24, and continue to float above the wafer support surface 24.

[0040] These areas are not sufficiently heated when the stage 21 reaches the processing position and the film formation process begins (right end of FIG. 8). As a result, the process proceeds with low temperature uniformity across the wafer W, and as a result, the thickness of the TiN film formed on the wafer W varies relatively greatly across the wafer W. Note that although it has been described that the lift pins 6A get stuck when the stage 21 moves from the standby position to the preheating position, this is only one example, and the sticking may occur at other times during the process.

[0041] To address this problem, it is conceivable to form the shaft 61 of the lift pin 6A and the hole wall surface 20 of the through-hole 25 so that the gap between the shaft 61 and the hole wall surface 20 is relatively large, thereby increasing the flowability of the cleaning gas in the gap and preventing the film 60 from remaining during the cleaning process. Specifically, it is conceivable to increase the flowability by making the diameter of the through-hole 25 larger than the diameter of the shaft 61.

[0042] However, if the diameter of the through-hole 25 is large relative to the diameter of the shank 61, the shank 61 may tilt relatively significantly within the through-hole 25, which may cause problems. Specifically, for example, the tilted shank 61 may climb onto the pin support surface 23 of the recess 22 or the wafer support surface 24 and remain supported thereon, preventing the lift pin 6 from moving up and down relative to the stage 21 as described in FIG. 6 . Furthermore, if the gap between the shank 61 and the hole wall surface 20 of the through-hole 25 becomes excessively large, the area of ​​the wafer W that overlaps the gap may not be sufficiently heated, resulting in a decrease in the uniformity of the temperature distribution within the wafer W. As a result, there is also a concern that the uniformity of the thickness of the TiN film formed on the wafer W may also decrease.

[0043] Therefore, in the film forming apparatus 1, grooves 63 forming a flow path for the cleaning gas are formed in the shaft portion 61 to improve the flowability of the cleaning gas between the shaft portion 61 and the hole wall surface 20 of the through-hole 25 and ensure that the film 60 on the shaft portion 61 is removed. The cleaning process in the film forming apparatus 1 will be described below with reference to FIG. 9 and the above-mentioned FIG. 5. These FIGS. 5 are schematic diagrams showing the gas flow in the processing chamber 11 with arrows, and FIG. 9 shows the gas flow around the lift pin 6 shown in FIG. 5 in more detail.

[0044] The stage 21 is positioned at the standby position, and the lift pins 6 are supported by the support base 33. At this time, the upper ends of the grooves 63 in the shaft portions 61 are positioned above the pin support surface 23 of the recesses 22 that form the upper surface of the stage 21. Because the grooves 63 are formed to reach the lower ends of the shaft portions 61, the lower ends of the grooves 63 are positioned below the lower surface of the stage 21. In other words, the lift pins 6 are positioned such that the grooves 63 extend from a height position above the through-holes 25 to a height position below the through-holes 25. Then, an inert gas is supplied from the shower head 52, and an inert gas and a cleaning gas are supplied from the gas supply ports 41 and 42, respectively, and these gases flow toward the exhaust port 15 as shown in FIG. 5 .

[0045] 9, part of the cleaning gas supplied into processing vessel 11 enters groove 63 from the lower side of stage 21 and flows upward through the gap formed by groove 63 and hole wall surface 20. The cleaning gas then flows out from this gap onto pin support surface 23 and toward exhaust port 15.

[0046] On the side surface of the shaft portion 61 of the lift pin 6, a relatively large gap is formed between the hole wall surface 20 and the portion where the groove 63 is formed. As described above, the groove 63 is formed from above the pin support surface 23 that forms the upper surface of the stage 21 to the lower surface of the stage 21, so that the gas inlet and outlet in the gap are large. Therefore, the cleaning gas flows into, through, and out of the gap formed by the groove 63 at a relatively high flow rate.

[0047] The gap formed between the portion of the side surface of the shank 61 outside the groove 63 and the hole wall surface 20 of the through-hole 25 is relatively small. However, as described above, the cleaning gas flows at a relatively high flow rate through the gap formed between the groove 63 and the hole wall surface 20, and the flow rate of the cleaning gas also becomes high in the gap formed by the portion outside the groove 63 that is continuous with the gap formed by the groove 63. Therefore, the cleaning gas flows at a higher flow rate in the portions around the shank 61 of the lift pin 6 than in the portions around the shank 61 of the lift pin 6A, and the film 60 formed on the portions of the side surface of the shank 61 is removed.

[0048] Note that TiN films adhering to other parts of the processing vessel 11 besides the shaft 61 are also removed by exposure to the cleaning gas. The cleaning process includes a stage (referred to as a lower-side cleaning stage) performed with the stage 21 in a standby state, as shown in FIGS. 5 and 9, and an upper-side cleaning stage. The upper-side cleaning stage is performed with the stage 21 in the processing position shown in FIG. 7, during which cleaning gas and inert gas are supplied from the shower head 52, and cleaning gas is also supplied from the gas supply port 42. The supplied gases flow into the exhaust port 15 and are exhausted, just as in the lower-side cleaning stage.

[0049] In this upper-side cleaning stage, the upper sides of the through-holes 25 are blocked by the heads 62 of the lift pins 6, making it more difficult for cleaning gas to flow into the gaps between the shafts 61 and the hole wall surfaces 20 than in the lower-side cleaning stage. Therefore, the film 60 on the shafts 61 of the lift pins is mainly removed in the lower-side cleaning stage. Either the lower-side cleaning or the upper-side cleaning may be performed first. After the cleaning process is completed, the loading into the processing chamber 11, film formation on the wafers W, and unloading of the wafers W from the processing chamber 11, which are described with reference to FIGS. 6 and 7, are resumed.

[0050] As described above, according to the film forming apparatus 1, even if a film 60 is formed on the side surface of the shaft portion 61 of the lift pin 6, the grooves 63 formed in the shaft portion 61 increase the flowability of cleaning gas around the shaft portion 61 during the cleaning process, and the film 60 is removed with high reliability. Therefore, it is possible to suppress variations in film thickness within the surface of the wafer W due to abnormal placement of the wafer W on the stage 21, as described in FIG. 8. As a result, it is possible to suppress a decrease in the yield of semiconductor products manufactured from the wafer W.

[0051] Furthermore, compared to the shaft portion 61 of the lift pin 6A, the shaft portion 61 of the lift pin 6 has a structure in which only a portion of the circumferential surface of the shaft portion 61 is recessed toward the center of the shaft portion 61 as a groove 63. This prevents the tilt of the lift pin 6, which would otherwise be caused by the through hole 25 being larger than the shaft portion 61, as described above. Furthermore, since the gap between the shaft portion 61 and the hole wall surface 20 of the through hole 25 is prevented from becoming excessively large, a decrease in the temperature uniformity of the wafer W is also suppressed.

[0052] Although the above description has been given assuming that film 60 is formed and grows on shank 61, even if a TiN film were to be formed and grow on hole wall surface 20, this could result in the wafer W being placed improperly as shown in Fig. 8. However, even if film 60 is formed on hole wall surface 20 in this way, the increased flowability of cleaning gas in the gap around shank 61 as described with reference to Figs. 5 and 9 ensures that film 60 is removed, thereby preventing such placement improperly.

[0053] The shape of the groove 63 formed in the shaft portion 61 is not limited to a shape in which the side surface and the bottom surface of the groove 63 are perpendicular to each other. For example, the width of the groove 63 may become narrower as it goes in the depth direction of the groove 63, so that the groove 63 is formed in a fan shape in cross section. The number of grooves 63 is not limited to four, either, and any number can be provided. Furthermore, the groove may be shaped so that one groove branches into multiple grooves as it extends, or multiple grooves merge as they extend.

[0054] The groove 63 is not limited to being formed along the extension direction of the shaft portion 61. For example, as shown in the side view of FIG. 10, the groove 63 may be formed spirally on the side surface of the shaft portion 61. As in FIG. 9, FIG. 10 also shows the lift pin 6 during the lower-side cleaning step, with the flow of gas indicated by dashed arrows. Furthermore, the shapes of the lift pin 6 and the through-hole 25 are not limited to the examples described above and may be modified as appropriate. For example, the lift pin 6 and the through-hole 25 may each have a rectangular shape in cross section.

[0055] 9, the stage 21 and the lift pins 6 are positioned such that the upper ends of the grooves 63 are located above the pin support surfaces 23 of the recesses 22, and the film 60 is removed by supplying cleaning gas from the gas supply ports 42 provided below the stage 21. With the stage 21 and the lift pins 6 positioned in this manner, the film 60 may be removed by supplying cleaning gas from the shower head 52 instead of supplying cleaning gas from the gas supply ports 42. That is, when removing the film 60, cleaning gas may be supplied to the grooves 63 from either the upper side or the lower side of the stage 21. However, in the film formation apparatus 1, when the stage 21 and the lift pins 6 are positioned as shown in FIG. 9, the exhaust port 15 is located above the stage 21. Therefore, in order to supply a sufficient amount of cleaning gas into the grooves 63, it is preferable to supply cleaning gas from the gas supply ports 42 below the stage 21, as described above.

[0056] FIG. 11 shows a longitudinal side view of a film formation apparatus 1 equipped with a lift pin 6B, another example of a lift pin. The lower end of this lift pin 6B is fixed to a support base 33 and moves up and down together with the support base 33. The lift pin 6B does not have a head 62, and a groove 63 is formed from the upper end to the lower end of the shaft 61. Therefore, the entire lift pin 6B forms the shaft 61, and the groove 63 is formed from the upper end to the lower end of the lift pin 6B. To match the shape of this lift pin 6B, the stage 21 does not have a recess 22, and a through-hole 25 is formed from the upper surface to the lower surface of the stage 21. When the support base 33 moves up and down relative to the stage 21 in the standby position, the upper end of the lift pin 6B protrudes and retracts into the wafer support surface 24 of the stage 21, thereby transferring the wafer W between the stage 21 and the transfer mechanism 10. During the lower-side cleaning stage, cleaning gas passes through the groove 63 as shown in FIG. 11 , and the film 60 on the side of the lift pin 6B is removed, just as with the lift pin 6.

[0057] As shown in lift pin 6B, the lift pin may be configured to be fixed to support base 33 without having a head 62, and the formation of groove 63 allows for more reliable removal of film 60. However, because lift pin 6B is fixed to support base 33 in this manner, it does not cause abnormal placement of wafer W due to continued support of stage 21 by the formed film 60, as described in FIG. 8 . Furthermore, when stage 21 is positioned at the processing position, lift pin 6B is removed from through-hole 25, and therefore, in the upper-side cleaning stage, lift pin 6B removed from through-hole 25 can be exposed to cleaning gas supplied from gas supply port 42. Therefore, it is particularly effective to form groove 63 on the shaft 61 of a lift pin, such as lift pin 6, which has a head 62 and a shaft 61 and is configured so that the shaft 61 is always positioned in through-hole 25.

[0058] The shape of the lift pin may be modified as appropriate from the examples described above, and may be a square rod, for example. The configuration of the film formation apparatus is not limited to the film formation apparatus 1 described above, and may be an apparatus that forms a type of film other than a TiN film. It is not limited to an apparatus that forms a film by ALD, and may be an apparatus that forms a film by CVD. The film formation apparatus 1 forms a film on the wafer W in an environment where no plasma is generated, but may be configured to form a film in a plasma environment.

[0059] Furthermore, in the film formation apparatus 1, exhaust port 15 is provided in the sidewall of the processing vessel 11 so as to surround the stage 21, and during the film formation process, exhaust is performed from the side of the stage 21 toward the outer periphery of the stage 21. The apparatus is not limited to having such a configuration in which exhaust port 15 is provided, and may have a configuration in which, for example, exhaust port 15 opens at the bottom of the processing vessel 11, and exhaust is performed downward from the stage 21 during the film formation process.

[0060] However, in a configuration in which exhaust port 15 is provided in the side wall of stage 21 and exhaust is directed toward the outer periphery of stage 21, as in film formation apparatus 1, the exhaust flow from exhaust port 15 is unlikely to flow through through holes 25. Therefore, if film formation gas leaks into through holes 25 as described above, the film formation gas will likely remain in through holes 25, making it easier to form film 60. In other words, the present technology is particularly effective when applied to a film formation apparatus in which exhaust port 15 is provided in the side wall of stage 21.

[0061] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and various omissions, substitutions, modifications, and combinations may be made in the above-described embodiments without departing from the scope and spirit of the appended claims.

[0062] Evaluation test Evaluation tests related to this technology will now be described. As Evaluation Test 1, a simulation was performed to measure the gas flow velocity distribution inside the processing chamber 11 of the film forming apparatus 1 in the lower side cleaning stage. In this simulation, N2 gas was supplied from the gas supply port 42 instead of the cleaning gas. Also, as Comparative Test 1, a simulation was performed with the same settings as Evaluation Test 1, except that the lift pins 6A described above were installed instead of the lift pins 6.

[0063] Figures 12 and 13 show the test results of Evaluation Test 1 and Comparative Test 1, respectively, and are schematic diagrams showing the distribution of gas flow velocity around lift pins 6 and 6A. The actual test results were obtained using computer graphics as images with a gradation display in which the color corresponds to the flow velocity of each part, but in Figures 12 and 13, the flow velocity distribution is shown by enclosing areas with similar flow velocities using contour lines and then applying patterns according to the range of flow velocities within the enclosed areas.

[0064] As shown in FIG. 13, in Comparative Test 1, the gas flow velocity in the gap between the shaft portion 61 of the lift pin 6A and the hole wall surface 20 of the through-hole 25 was relatively low. However, as shown in FIG. 12, in Evaluation Test 1, the gas flow velocity in the gap between the groove 63 of the shaft portion 61 and the hole wall surface 20 was higher than the flow velocity in the above gap in Comparative Test 1. More specifically, in Comparative Test 1, the flow velocity at some locations in the gap was 0.003 m / sec, and in Evaluation Test 1, the flow velocity at some locations in the gap was 0.015 m / sec. It is obvious that cleaning gas behaves similarly to N2 gas, and therefore Evaluation Test 1 and Comparative Test 1 demonstrate that providing groove 63 can improve the flowability of cleaning gas in the gap between shaft portion 61 and hole wall surface 20. Therefore, from these tests, it is estimated that abnormalities in the placement state of wafer W can be prevented, as described in the embodiment. [Explanation of symbols]

[0065] W wafer 11 Processing container 21 Stages 28, 35 Lifting mechanism 44 Cleaning gas supply unit 57 Gas Supply Section 6 lift pins 63 Groove

Claims

1. a processing chamber having an evacuated interior and a stage for placing a substrate thereon; a first gas supply unit that supplies a film formation gas into the processing chamber in order to form a film on the substrate placed on the stage; a second gas supply unit that supplies a cleaning gas that removes a film formed in the processing vessel by the film forming gas when the substrate is not stored in the processing vessel; a through hole formed in the stage in a vertical direction; a substrate support member disposed in the through hole and extending in a vertical direction to support the substrate; a height changing mechanism that changes the relative height between the stage and the substrate support member so that the substrate can be switched between a state in which the substrate is supported by the stage and a state in which the substrate is supported by the substrate support member; a groove formed on a side surface of the substrate support member and forming a flow path for the cleaning gas; A film forming apparatus comprising:

2. the substrate support member includes a shaft portion and a head portion having an area larger than that of the shaft portion when viewed in an extension direction of the substrate support member and provided above the shaft portion; The stage has a recess formed therein for accommodating the head, the bottom surface of which forms a part of the upper surface of the stage, The film deposition apparatus according to claim 1 , wherein the groove is provided in the shaft portion.

3. 3. The film forming apparatus according to claim 2, wherein when the cleaning gas is supplied into the processing chamber, the upper end of the groove is located above the upper surface of the stage and the lower end of the groove is located below the lower surface of the stage.

4. The film deposition apparatus according to claim 2 , wherein the grooves are provided in a plurality of locations spaced apart from each other in the extending direction of the substrate support member.

5. 2. The film forming apparatus according to claim 1, wherein an exhaust port is provided in a sidewall of the processing vessel for exhausting air toward an outer periphery of the stage.

6. placing the substrate on a stage provided inside the processing chamber and having a through-hole formed in the vertical direction; evacuating the interior of the processing vessel; supplying a film formation gas into the processing vessel from a first gas supply unit to form a film on the substrate placed on the stage; supplying a cleaning gas into the processing vessel from a second gas supply unit while the substrate is not stored in the processing vessel, thereby removing a film formed in the processing vessel by the film forming gas; changing the relative height of the stage and the substrate support member by a height change mechanism so that the substrate is switched between a state in which it is supported by the stage and a state in which it is supported by the substrate support member; a step of passing the cleaning gas through a groove formed on a side surface of the substrate support member and forming a flow path for the cleaning gas; A film forming method comprising:

7. a processing chamber having an evacuated interior and a stage for placing a substrate thereon; a first gas supply unit that supplies a film formation gas into the processing chamber in order to form a film on the substrate placed on the stage; a second gas supply unit that supplies a cleaning gas that removes a film formed in the processing vessel by the film forming gas when the substrate is not stored in the processing vessel; a through hole formed in the stage in a vertical direction; a substrate support member disposed in the through hole and extending in a vertical direction to support the substrate; a height changing mechanism that changes a relative height between the stage and the substrate support member so that the substrate can be switched between a state in which the substrate is supported by the stage and a state in which the substrate is supported by the substrate support member, A substrate support member having a groove formed on a side surface of the substrate support member, the groove forming a flow path for the cleaning gas.

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