Liquid treatment method and liquid treatment device

Abstract

The present invention provides a liquid processing method and a liquid processing apparatus capable of supplying a processing liquid to a ring-shaped region other than a peripheral edge of the back surface of a substrate to perform local processing. The liquid processing method includes: a step of placing a center portion of the back surface of the substrate on a placement table and rotating the placement table; and a step of supplying a mist-shaped processing liquid from a nozzle to a position closer to the center than the peripheral edge of the back surface of the rotating substrate, and causing the processing liquid to volatilize so that the processing liquid is not supplied to the peripheral edge of the substrate by centrifugal force, thereby locally processing the ring-shaped region of the back surface of the substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid processing method and a liquid processing apparatus. BACKGROUND

[0002] In a manufacturing process of a semiconductor device, a liquid processing apparatus is used to supply various kinds of processing liquids to a semiconductor wafer (hereinafter, referred to as a wafer) as a substrate to perform liquid processing. As one example of the liquid processing, there is a process of supplying a cleaning liquid to the back surface of the wafer to perform cleaning. Patent Literature 1 discloses a wafer cleaning apparatus in which a nozzle that is a structure to release a flow of the cleaning liquid is provided on the back surface side of the wafer, and the cleaning liquid released from the nozzle is spread on the back surface of the wafer by centrifugal force generated by rotation of the wafer to perform cleaning.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2013-120911 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique capable of supplying a processing liquid to a ring-shaped region other than a peripheral end of a back surface of a substrate to perform local processing.

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] The liquid processing method of the present application includes a step of placing a center portion of a back surface of a substrate on a placement table and rotating the placement table, and a step of supplying a processing liquid in a mist state from a nozzle to a position closer to the center than a peripheral end of the back surface of the substrate being rotated, and volatilizing the processing liquid so that the processing liquid is not supplied to the peripheral end of the substrate by centrifugal force, thereby locally processing a ring-shaped region of the back surface of the substrate.

[0010] EFFECTS OF THE INVENTION

[0011] The present application can supply a processing liquid to a ring-shaped region other than a peripheral end of a back surface of a substrate to perform local processing. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a longitudinal sectional side view of a liquid processing apparatus of one embodiment of the present application.

[0013] Figure 2 is a plan view of the above-described liquid processing apparatus.

[0014] Figure 3 is a process chart showing processing performed by the above-described liquid processing apparatus.

[0015] Figure 4 is a process chart showing the treatment by the liquid treatment device.

[0016] Figure 5 is a process chart showing the treatment by the liquid treatment device.

[0017] Figure 6 is a process chart showing the treatment by the liquid treatment device.

[0018] Figure 7 is a process chart showing the treatment by the liquid treatment device.

[0019] Figure 8 is an explanatory view showing the state of the cleaning liquid in the above treatment process.

[0020] Figure 9 is an explanatory view showing the state of the cleaning liquid in the above treatment process.

[0021] Figure 10 is an explanatory view showing the state of the cleaning liquid in the above treatment process.

[0022] Figure 11 is an explanatory view showing the state of the cleaning liquid in the above treatment process.

[0023] Figure 12 is a longitudinal sectional side view showing an example of a nozzle provided in the above liquid treatment device.

[0024] Figure 13 is a side view showing another example of the above nozzle.

[0025] Figure 14 is a plan view showing the relationship between the discharge port of the above nozzle and the projection.

[0026] Figure 15 is a longitudinal sectional side view showing another example of the above liquid treatment device.

[0027] Figure 16 is a plan view showing still another example of the above liquid treatment device.

[0028] Figure 17 is an explanatory view showing the results of comparative tests.

[0029] Figure 18 is an explanatory view showing the results of comparative tests.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] T liquid flow, W wafer, 11 rotary chuck, 41 cleaning nozzle. DETAILED DESCRIPTION

[0032] An embodiment of the liquid processing apparatus 1 of the present application will be described below. The liquid processing apparatus 1 is used to form an anti-pollution film R on a circular substrate, i.e., a wafer W having a diameter of, for example, 300 mm, from the peripheral portion on the back surface side through the side surface of the wafer W to the peripheral portion on the front surface side. That is, the anti-pollution film R is a ring-shaped film formed to locally cover the peripheral portion on the back surface and the front surface of the wafer W, respectively, and to cover the entire circumferential direction of the wafer W. The anti-pollution film R is further described in detail, for example, by a metal-free resist. Also, the anti-pollution film R is formed to prevent the peripheral portion of the wafer W from being contaminated with metal when, for example, a resist film is formed by applying a metal-containing resist to the entire front surface of the wafer W by spin coating after that.

[0033] In the liquid processing apparatus 1, in order to remove foreign matter attached to the wafer W when the anti-pollution film R is formed or before being transported into the liquid processing apparatus 1, a cleaning liquid is supplied to a ring-shaped region around the center portion of the back surface of the wafer W. In order to prevent the anti-pollution film R from being removed by the cleaning liquid, the liquid processing apparatus 1 is configured to be capable of supplying the cleaning liquid in a mist state, which will be described later in detail.

[0034] Next, the structure of the liquid processing apparatus 1 will be described with reference to Figure 1 , a plan view Figure 2 . In the drawing, 11 is a rotary chuck that constitutes a stage for holding and rotating the wafer W, and is used to adsorb the center portion of the back surface of the wafer W to horizontally hold the wafer W. The rotary chuck 11 is connected to a rotating mechanism 13 via a vertically extending rotating shaft 12, and is capable of rotating the wafer W held by the rotary chuck 11 about the vertical axis by the rotating mechanism 13.

[0035] In the drawing, 21 is a cup-shaped body that surrounds the wafer W held by the rotary chuck 11. An exhaust pipe 22 is connected to the cup-shaped body 21, and is capable of exhausting the inside of the cup-shaped body 21 by an exhaust source not shown during processing of the wafer W. In the drawing, 23 is a baffle provided in the exhaust pipe 22, and is capable of adjusting the exhaust amount in the cup-shaped body 21 by adjusting the opening degree of the baffle according to a control signal to be described later. In the drawing, 24 is a drain pipe for removing various liquids from the cup-shaped body 21. In the drawing, 25 is a lift pin, and is capable of transferring the wafer W between a wafer W transport mechanism not shown and the rotary chuck 11 by lifting the lift pin 25 by a lift mechanism 26.

[0036] In addition, a horizontal stage 31 is provided in the cup-shaped body 21 so as to surround the above-mentioned rotating shaft 12, and a lower film forming nozzle 32 and a cleaning nozzle 41 are provided on the stage 31. These nozzles are provided at intervals in the rotating direction of the wafer W below the wafer W placed on the rotating chuck 11. The lower film forming nozzle 32 is connected to a resist supply mechanism 34 via a pipe 33. The resist supply mechanism 34 includes a valve, a pump, a tank, and the like, and is capable of pressure-feeding the resist stored in the tank to the lower film forming nozzle 32. The lower film forming nozzle 32 is capable of releasing the resist to the obliquely upper side from the center side of the wafer W to the outer side, and supplying the resist to the peripheral portion of the back surface of the wafer W. The resist is used to form the lower portion of the above-mentioned contamination preventing film R. 32A in the drawing is a release port of the lower film forming nozzle 32.

[0037] The cleaning nozzle 41 is connected to a cleaning liquid supply mechanism 44 and an air supply mechanism 45 via pipes 42 and 43, respectively. The cleaning liquid is, for example, a diluent. The cleaning liquid supply mechanism 44 and the air supply mechanism 45 are configured similarly to the resist supply mechanism 34, except that the cleaning liquid and the air are supplied to the cleaning nozzle 41, respectively. Therefore, the cleaning liquid and the air can be supplied to the cleaning nozzle 41 by opening the valves included in the cleaning liquid supply mechanism 44 and the air supply mechanism 45, respectively. The supply of the cleaning liquid and the air to the cleaning nozzle 41 is performed simultaneously, and the cleaning liquid is finely dispersed, that is, atomized by the air in the cleaning nozzle 41. That is, the air is a mist forming gas. The cleaning liquid and the air are supplied to the cleaning nozzle 41 at a flow rate corresponding to the opening degree of the valve of the cleaning liquid supply mechanism 44 and the air supply mechanism 45, respectively, and the opening degree of each valve is set in advance so as to finely disperse the cleaning liquid to an appropriate size in the nozzle.

[0038] The mist of the cleaning liquid thus generated in the cleaning nozzle 41 is released to the obliquely upper side from the center side of the wafer W to the outer side. The mist of the cleaning liquid is supplied to the area of the back surface of the wafer W, which is outside the area overlapping the rotating chuck 11 and is closer to the center of the wafer W than the position where the contamination preventing film R is formed.

[0039] In addition, a lower film forming nozzle 32 is provided in the cup-shaped body 21 so as to surround the above-mentioned rotating shaft 12, and a cleaning nozzle 41 is provided on the stage 31. These nozzles are provided at intervals in the rotating direction of the wafer W below the wafer W placed on the rotating chuck 11. The lower film forming nozzle 32 is connected to a resist supply mechanism 34 via a pipe 33. The resist supply mechanism 34 includes a valve, a pump, a tank, and the like, and is capable of pressure-feeding the resist stored in the tank to the lower film forming nozzle 32. The lower film forming nozzle 32 is capable of releasing the resist to the obliquely upper side from the center side of the wafer W to the outer side, and supplying the resist to the peripheral portion of the back surface of the wafer W. The resist is used to form the lower portion of the above-mentioned contamination preventing film R. 32A in the drawing is a release port of the lower film forming nozzle 32.

[0040] The upper film forming nozzle 51 is connected to a resist supply mechanism 56 via a pipe 55. The resist supply mechanism 56 is configured similarly to the resist supply mechanism 34, and the upper film forming nozzle 51 is able to release the resist pressurized from the resist supply mechanism 56 downward in the vertical direction. The resist released from the upper film forming nozzle 51 is used to form the upper portion of the aforementioned contamination preventing film R.

[0041] The liquid processing apparatus 1 includes a control section 10 constituted by a computer. The control section 10 has a program in which a group of steps is incorporated, and is able to send control signals to each section of the apparatus to implement the processes described later. Specifically, the control signals described above can be used to control the supply and cutoff of fluid from each supply mechanism to the nozzles, the rotation speed of the wafer W by the rotation mechanism 13, the opening of the baffle 23, the raising and lowering of the lift pins 25 by the lift mechanism 26, and the like. The program described above can be installed by being stored in a storage medium such as an optical disk, a hard disk, a memory card, a DVD, or the like.

[0042] Referring to the process chart of Figures 3-7 , a series of processes performed by the liquid processing apparatus 1 described above will be described. Also, reference is made to the schematic view showing the case where the cleaning liquid is supplied to the back surface of the wafer W, i.e. Figures 8-11 . First, the center portion of the wafer W transported to the back surface of the liquid processing apparatus 1 by a transport mechanism not shown is adsorbed on the spin chuck 11, and the wafer W is caused to rotate at a prescribed rotation speed. Then, the resist R0 is released from the lower film forming nozzle 32 to the peripheral portion of the back surface of the wafer W. The resist R0 flows to the side from the back surface of the wafer W due to the centrifugal force of the rotation of the wafer W and dries, forming the lower film R2 Figure 3 .

[0043] The release of the resist from the lower film forming nozzle 32 is stopped. Then, the upper film forming nozzle 51 releases the resist R0 while moving from the outer side of the wafer W upward to above the peripheral portion of the wafer W which is rotating at a prescribed rotation speed. Thus, the resist R0 is supplied from the upper end of the lower film R2 to the peripheral portion of the front surface side of the wafer W Figure 4 . After that, the release of the resist R0 from the upper film forming nozzle 51 is stopped, and the upper film forming nozzle 51 retreats from above the wafer W. The resist R0 released from the upper film forming nozzle 51 dries, and the aforementioned contamination preventing film R is formed from the resist R0 and the lower film R2 Figure 5 .

[0044] Then, while the wafer W is rotating at a prescribed rotation speed, the cleaning nozzle 41 is supplied with air and cleaning liquid, and the cleaning liquid is released in mist form from the cleaning nozzle 41 Figure 6 、 Figure 8The cleaning fluid droplets T accumulate on the back side of the wafer W. Part of the accumulated liquid falls off the wafer W due to its own weight, while the other part forms a liquid film T0 and remains on the back side of the wafer W. This liquid film T0 expands towards the periphery of the wafer W due to the centrifugal force of the wafer W's rotation, coming into contact with foreign matter P adhering to the back side of the wafer W. Figure 9 The foreign object P is either washed away from the back side of the wafer W by the liquid film T0, or dissolved in the liquid film T0 and removed from the back side of the wafer W. Figure 10 ).

[0045] By releasing the cleaning fluid in a mist state, the amount of cleaning fluid supplied per unit time to the location facing the cleaning nozzle 41 on the back side of the wafer W is less, resulting in a thin liquid film T0 at that location. Furthermore, the diluent forming the liquid film T0 evaporates as it travels towards the periphery of the wafer W, exposed to the airflow generated around the wafer W by the rotation of the wafer W and the exhaust within the cup-shaped body 21. Through this evaporation, the liquid film T0 becomes even thinner at the periphery of the wafer W, preventing it from reaching the anti-fouling membrane R. The dashed arrows in the figure indicate the evaporated cleaning fluid.

[0046] Thus, the area of ​​the liquid film T0 formed on the back side of the wafer W (= the area being cleaned) is a local annular region extending from the outer side of the area overlapping with the rotary chuck 11 to a position closer to the center of the wafer W than the position where the anti-contamination film R is formed. Then, the supply of air and cleaning liquid to the cleaning nozzle 41 is stopped, and the release of cleaning liquid mist from the cleaning nozzle 41 is stopped. Figure 11 Then, stop the rotation of wafer W. Figure 7 The wafer W is fed out from the liquid processing unit 1 using a transport mechanism (not shown).

[0047] As described above, in the liquid treatment apparatus 1, when cleaning the annular region outside the area overlapping the rotating chuck 11 on the back side of the wafer W, the cleaning liquid is sprayed onto the rotating wafer W. This causes the cleaning liquid, which is moved by the centrifugal force of rotation, to evaporate and be removed before reaching the periphery of the wafer W, preventing the cleaning liquid from being supplied to the anti-contamination film R. Therefore, it is possible to prevent the anti-contamination film R from dissolving or being washed away from the wafer W due to contact with the cleaning liquid. As a result, metal contamination at the periphery of the wafer W can be prevented, thus suppressing a decrease in the yield of semiconductor products manufactured from the wafer W.

[0048] To promote the volatilization of the liquid film T0 of the cleaning liquid and more reliably prevent the removal of the contamination prevention film R, for example, the opening degree of the baffle 23 at the time of the release of the cleaning liquid from the cleaning nozzle 41 can be made larger than the opening degree of the baffle 23 at the time of the release of the resist R0 from the lower film forming nozzle 32 and the upper film forming nozzle 51, respectively. That is, the exhaust amount in the cup-shaped body 21 at the time of the cleaning is made larger than the exhaust amount in the cup-shaped body 21 at the time of the formation of the contamination prevention film R, and the volatilization caused by the air current can be promoted.

[0049] In addition, the rotational speed of the wafer W at the time of the release of the cleaning liquid from the cleaning nozzle 41 can be made larger than the rotational speed of the wafer W at the time of the release of the resist R0 from the lower film forming nozzle 32 and the upper film forming nozzle 51, respectively, and the volatilization of the cleaning liquid caused by the air current generated by the rotation of the wafer W can be promoted. To sufficiently promote the volatilization of the liquid film T0 and prevent the liquid film T0 from contacting the contamination prevention film R, the rotational speed of the wafer W at the time of the release of the cleaning liquid is, for example, 1000 rpm or more, and preferably 1500 rpm or more.

[0050] The cleaning nozzle 41 described above is, for example, provided on the stage 31 so as to be capable of changing the angle with respect to the horizontal plane and the height with respect to the stage 31, and the angle and the height can be manually changed by the user of the apparatus, and the release position of the cleaning liquid on the wafer W can be adjusted. With such a configuration, the position of the area of the back surface of the wafer W to which the cleaning liquid is supplied and the area of the area can be adjusted.

[0051] The change of the angle (i.e., the orientation of the nozzle with respect to the wafer W) and the height (i.e., the position of the nozzle with respect to the wafer W) of the cleaning nozzle 41 described above can also be performed by a driving mechanism. Figure 12 In the example of the structure of the apparatus shown, as the driving mechanism, there are a rotation mechanism 61 and a lifting mechanism 62. The cleaning nozzle 41 is connected to the rotation mechanism 61, and the rotation mechanism 61 is connected to the lifting mechanism 62. The rotation mechanism 61 is liftable by the lifting mechanism 62. By rotating the cleaning nozzle 41 about the horizontal axis by the rotation mechanism 61, the angle with respect to the horizontal plane can be changed.

[0052] In addition, for example, the lower film forming nozzle 32 described above is configured to be movable along the radial direction of the wafer W by a moving mechanism, and the movement is controlled by the control section 10. That is, by making the lower film forming nozzle 32 movable, the position of the end portion of the contamination prevention film R on the back surface side of the wafer W near the center can be controlled. In this case, the control section 10 can control the operation of the rotation mechanism 61 and the lifting mechanism 62 in correspondence with the position of the lower film forming nozzle 32, i.e., the position of the end portion of the contamination prevention film R on the back surface side of the wafer W near the center of the wafer W, and change the position of the mist of the cleaning liquid supplied to the back surface of the wafer W.

[0053] Specifically, for example, the closer the end portion of the contamination preventing film R is to the peripheral edge of the wafer W, the closer the supply position of the mist of the cleaning liquid to the back surface of the wafer W (the position at which the discharge port of the cleaning nozzle 41 faces in the discharge direction of the cleaning nozzle 41) is made to the peripheral edge of the wafer W. By thus controlling the supply position of the mist, the position at which the liquid film TO disappears due to evaporation can be made to be in the vicinity of the contamination preventing film R, cleaning can be performed on the vicinity of the contamination preventing film R which is considered to be more likely to have the foreign matter P attached thereto when the contamination preventing film R is formed, and the liquid film TO can be prevented from contacting the contamination preventing film R as described above.

[0054] Further, the above adopts a configuration in which the supply position of the mist to the back surface of the wafer W is changed by the actions of both the rotation mechanism 61 and the elevation mechanism 62, but it can also be a configuration in which only either one of the rotation mechanism 61 and the elevation mechanism 62 is provided to change the supply position of the mist. Further, as the drive mechanism of the cleaning nozzle 41 for changing the cleaning position, it is not limited to being configured as the rotation mechanism 61 and the elevation mechanism 62, but for example, it can be configured as a movement mechanism that moves the position of the cleaning nozzle 41 on the stage 31 in the radial direction of the wafer W.

[0055] Further, the above adopts a configuration in which the supply position of the mist to the back surface of the wafer W is changed by the actions of both the rotation mechanism 61 and the elevation mechanism 62, but it can also be a configuration in which only either one of the rotation mechanism 61 and the elevation mechanism 62 is provided to change the supply position of the mist. Further, as the drive mechanism of the cleaning nozzle 41 for changing the cleaning position, it is not limited to being configured as the rotation mechanism 61 and the elevation mechanism 62, but for example, it can be configured as a movement mechanism that moves the position of the cleaning nozzle 41 on the stage 31 in the radial direction of the wafer W. Figure 12

[0056] Further, the above adopts a configuration in which the supply position of the mist to the back surface of the wafer W is changed by the actions of both the rotation mechanism 61 and the elevation mechanism 62, but it can also be a configuration in which only either one of the rotation mechanism 61 and the elevation mechanism 62 is provided to change the supply position of the mist. Further, as the drive mechanism of the cleaning nozzle 41 for changing the cleaning position, it is not limited to being configured as the rotation mechanism 61 and the elevation mechanism 62, but for example, it can be configured as a movement mechanism that moves the position of the cleaning nozzle 41 on the stage 31 in the radial direction of the wafer W. Figure 13 The cleaning nozzle 47 illustrated in FIG. 7 is configured in the same manner as the cleaning nozzle 41 except for the shape of the discharge port, and the shape of the discharge port 47A provided on the cleaning nozzle 47 is a square-shaped slit. Further, in FIG. 7, the black dots in the inside of the nozzle represent the cleaning liquid, and the elongated lines represent the air. Figure 13

[0057] In FIG. 7, the projection region of the above-described discharge port 47A onto the back surface of the wafer W in the direction in which the cleaning liquid is discharged is indicated as 47B. Figure 14 ​​The length of the wafer W in the X direction, which is the radial direction of the projection region 47B, is smaller than the length of the wafer W in the Y direction, which is orthogonal to the X direction. Therefore, the cleaning nozzle 47 is configured to be able to supply a relatively large amount of cleaning liquid per unit time to the wafer W, and the range of the mist of the cleaning liquid supplied to the wafer W in the radial direction is small. Since the range of the mist supplied in the radial direction is small, the spread of the liquid film TO in the radial direction of the wafer W can be suppressed. Therefore, by using the cleaning nozzle 47, the removal of the anti-pollution film R can be more reliably suppressed.

[0058] In addition, in addition to the Figure 13 , Figure 14 example, the release port 47A can be formed, for example, as an oval opening or as a curved slit. In the case where the release port 47A is formed in this way, it is also preferable to arrange the cleaning nozzle 47 in such a manner that the length of the X direction of the projection region 47B is < the length of the Y direction (more specifically, the length between one end and the other end in the X direction is < the length between one end and the other end in the Y direction).

[0059] Next, with reference to Figure 15 , Figure 16 , a liquid processing apparatus 7 as another embodiment will be described, focusing on the differences from the liquid processing apparatus 1. In the liquid processing apparatus 7, a volatilization promoting mechanism for promoting the volatilization of the cleaning liquid supplied to the wafer W is provided. As the volatilization promoting mechanism, a heating unit 71, 72, a dry gas supply unit 73, and a heated gas supply unit 81 are included.

[0060] The heating unit 71 is provided on the pipe 42 and has a heater that heats the flow of the cleaning liquid flowing in the pipe 42 toward the cleaning nozzle 41. In addition, the heating unit 72 is provided on the pipe 43 and has a heater that heats the air flowing in the pipe 43 toward the cleaning nozzle 41.

[0061] The dry gas supply unit 73 has a dry gas nozzle 74 and a dry gas supply mechanism 75. The dry gas nozzle 74 is provided on the table 31 at a position spaced apart from the cleaning nozzle 41 in the rotation direction of the wafer W and is capable of releasing dry gas obliquely upward from the center portion side of the wafer W toward the peripheral portion side. The dry gas flows along the back surface of the wafer W to promote the drying of the liquid film TO, and for this purpose, the position of the back surface of the wafer W to which the dry gas is supplied (the position toward which the release port of the dry gas nozzle 74 is directed) is a position closer to the center of the wafer W than the end portion of the anti-pollution film R. The dry gas supply mechanism 75 is configured similarly to the air supply mechanism 45, except that it supplies, for example, N2 gas (nitrogen) as the dry gas to the dry gas nozzle 74.

[0062] Next, the heated gas supply section 81 will be described. This heated gas supply section 81 includes a gas nozzle 82, a pipe 83, a heating section 84, a gas supply mechanism 85, an arm 86, and a moving mechanism 87. The moving mechanism 87 is capable of elevating the arm 86 as well as moving it along the guide 54. Thus, the gas nozzle 82 provided at the front end of the arm 86 is capable of moving between the center portion of the wafer W and the outside of the cup-shaped body 21.

[0063] In addition, the gas nozzle 82 and the gas supply mechanism 85 are connected via the pipe 83. The gas supply mechanism 85 is configured as the dry gas supply mechanism 75 to supply N2gas to the gas nozzle 82. The heating section 84 provided on the pipe 83 has a heater, and the N2gas is heated to a temperature higher than the temperature of the surroundings of the wafer W at the midway to the gas nozzle 82, and is released as heated gas from the gas nozzle 82 to the vertically downward direction.

[0064] In the liquid processing apparatus 7, after the contamination prevention film R is formed in the same procedure as the liquid processing apparatus 1, the cleaning liquid and air are supplied to the cleaning nozzle 41, respectively. The cleaning liquid and the air are heated by the heating sections 71 and 72, respectively, and are supplied to the cleaning nozzle 41, whereby the mist of the cleaning liquid at a temperature higher than the temperature of the surroundings of the wafer W is released from the cleaning nozzle 41 to the wafer W rotating as described above. Figures 8-11 The wafer W is cleaned as described above. The mist of the cleaning liquid is at a relatively high temperature, and thus the above-mentioned liquid film TO formed by the mist is easily volatilized. Thus, the contamination prevention film R can be more reliably prevented from being removed by the liquid film TO. Further, because the temperature is high, the cleaning effect of the liquid film TO is strong, and thus the foreign matter P can be more reliably removed from the back surface of the wafer W.

[0065] In addition, in the liquid processing apparatus 7, in parallel with the release of the mist of the cleaning liquid from the above-mentioned cleaning nozzle 41, the supply of the heated N2gas (heated gas) to the center portion of the front surface of the wafer W by the gas nozzle 82 and the supply of the N2gas (dry gas) to the back surface of the wafer W by the dry gas nozzle 74 are performed. The heated gas spreads from the center to the periphery of the front surface of the wafer W by the centrifugal force caused by the rotation of the wafer W and the exhaust in the cup-shaped body 21. The wafer W is heated by being exposed to the heated gas, and thus the cleaning effect by the mist of the cleaning liquid is enhanced, and the volatilization of the above-mentioned liquid film TO of the cleaning liquid is promoted. Further, the dry gas flows to the periphery of the wafer W by the centrifugal force caused by the rotation of the wafer W and the exhaust in the cup-shaped body 21. The liquid film TO is exposed to the dry gas, and the volatilization is promoted. Thus, by the respective effects of the heated gas and the dry gas, the drying of the liquid film TO is promoted, and the contamination prevention film R can be more reliably prevented from being removed by the liquid film TO.

[0066] Any one of the above-described heating sections 71, 72, the dry gas supply section 73, and the heating gas supply section 81 can be provided to promote volatilization of the cleaning liquid. Further, the above-described heating gas and dry gas are not limited to N2 gas, and for example, can be other inert gases such as Ar (argon) or air. Further, when volatilization of the cleaning liquid is promoted by heating the wafer W, the heating gas supply section 81 is not limited to be provided. For example, a heater can be embedded in the rotary chuck 11 to heat the wafer W. Further, a light irradiation section composed of an LED or the like can be provided on the stage 31 to irradiate light to the back surface of the wafer W to heat the wafer W.

[0067] As the gas supplied to the cleaning nozzle 41, only a gas that can atomize the cleaning liquid is required, and thus the gas is not limited to air, and for example, can be an inert gas such as N2 gas. Further, when the wafer W is cleaned, the wafer W on which the contamination preventing film R is not formed can be processed in such a manner that the cleaning liquid is not supplied to the peripheral end of the wafer W. Further, as the cleaning liquid, the cleaning liquid is not limited to a diluent, and for example, can be IPA (isopropyl alcohol), pure water, or the like.

[0068] Further, when the wafer W is cleaned as described above, even if a trace amount of the cleaning liquid is supplied to the contamination preventing film R, and a part of the surface of the contamination preventing film R is removed by the cleaning liquid, as long as the entire periphery of the peripheral edge portion of the back surface of the wafer W after cleaning is covered with the contamination preventing film R. That is, volatilization of the cleaning liquid is performed so that the contamination preventing film R is not removed from the back surface of the wafer W, and a case in which only a part of the contamination preventing film R is removed by cleaning processing is included.

[0069] Further, as the processing of the wafer W, the processing is not limited to cleaning, and for example, a coating liquid can be supplied to form a coating film in a ring shape on the wafer W. In this case, a solvent constituting the coating liquid supplied to the wafer W in a mist state is volatilized before reaching the peripheral end of the wafer W, and thus, the coating film can be formed in a ring-shaped region on the back surface of the wafer W except for the peripheral end.

[0070] The above-described embodiments can be omitted, replaced, changed, or combined in various ways without departing from the scope of the appended claims and the spirit thereof.

[0071] (Reference Test)

[0072] As a comparative test, a resist film was formed on the entire back surface of the wafer W, and cleaning processing of the back surface of the wafer W was performed using the liquid processing apparatus 1. Then, the wafer W after the cleaning processing was photographed. Further, as a comparative test, a resist film was formed on the entire back surface of the wafer W, and cleaning processing of the back surface of the wafer W was performed using a liquid processing apparatus for the comparative test, and the wafer W after the cleaning processing was photographed. The liquid processing apparatus for the comparative test was configured in the same manner as the liquid processing apparatus 1 except that the cleaning liquid was discharged as a stream from the cleaning nozzle.

[0073] Figure 17 An image obtained in the comparative test is shown in FIG. 6. In the comparative test, the resist film was removed from the position on the back surface of the wafer W outward of the central portion to the peripheral edge, but, as shown in FIG. 6, the resist film remained on the peripheral edge portion of the wafer W. Thus, according to the comparative test, it was confirmed that the cleaning liquid was supplied to the peripheral edge of the wafer W by discharging the cleaning liquid as a stream from the cleaning nozzle. Figure 18 An image obtained in the comparative test is shown in FIG. 6. In the comparative test, the resist film was removed from the position on the back surface of the wafer W outward of the central portion to the peripheral edge, but, as shown in FIG. 6, the resist film remained on the peripheral edge portion of the wafer W. Thus, according to the comparative test, it was confirmed that the cleaning liquid was supplied to the peripheral edge of the wafer W by discharging the cleaning liquid as a stream from the cleaning nozzle. Figure 18 An image obtained in the comparative test is shown in FIG. 6. In the comparative test, the resist film was removed from the position on the back surface of the wafer W outward of the central portion to the peripheral edge, but, as shown in FIG. 6, the resist film remained on the peripheral edge portion of the wafer W. Thus, according to the comparative test, it was confirmed that the cleaning liquid was supplied to the peripheral edge of the wafer W by discharging the cleaning liquid as a stream from the cleaning nozzle. Figure 17 An image obtained in the comparative test is shown in FIG. 6. In the comparative test, the resist film was removed from the position on the back surface of the wafer W outward of the central portion to the peripheral edge, but, as shown in FIG. 6, the resist film remained on the peripheral edge portion of the wafer W. Thus, according to the comparative test, it was confirmed that the cleaning liquid was supplied to the peripheral edge of the wafer W by discharging the cleaning liquid as a stream from the cleaning nozzle.

Claims

1. A liquid treatment method, characterized by, Comprising: a process of placing a center portion of the back surface of a substrate on a placement table and rotating the placement table; and a process of supplying a treatment liquid in mist form to a position closer to the center than the periphery of the back surface of the substrate being rotated from a nozzle and causing the treatment liquid to volatilize so that the treatment liquid is not supplied to the periphery of the substrate by centrifugal force, thereby locally processing a ring-shaped region of the back surface of the substrate, a length of a projection region obtained by projecting an opening of the nozzle on the substrate in a radial direction of the substrate is smaller than a length of the projection region in a direction orthogonal to the radial direction.

2. The liquid processing method according to claim 1, wherein: the treatment liquid is a cleaning liquid for cleaning the back surface of the substrate.

3. The liquid processing method according to claim 1 or 2, wherein: a process of forming a ring-shaped film locally covering the peripheral portion on the back surface of the substrate is included, the process of locally processing the ring-shaped region includes a process of causing the treatment liquid to volatilize so that the ring-shaped film is not removed.

4. The liquid processing method according to claim 1 or 2, wherein: a process of heating the substrate while supplying the treatment liquid to the substrate is included.

5. The liquid processing method according to claim 4, wherein: the process of heating the substrate includes a process of supplying a heating gas for heating the substrate to the front surface of the substrate.

6. The liquid processing method according to claim 1 or 2, wherein: the process of locally processing the ring-shaped region includes a process of simultaneously supplying a liquid flow of the treatment liquid and a mist-forming gas for atomizing the treatment liquid to the nozzle, the liquid processing method includes a process of heating the liquid flow of the treatment liquid or the mist-forming gas to be supplied to the nozzle.

7. The liquid processing method according to claim 1 or 2, wherein: a process of supplying a drying gas for promoting volatilization of the treatment liquid to the back surface of the substrate while supplying the treatment liquid in mist form to the substrate is included.

8. The liquid processing method according to claim 1 or 2, wherein: a process of changing a position of the substrate to which the treatment liquid in mist form is supplied by changing a position of the nozzle with respect to the substrate or an orientation of the nozzle with respect to the substrate by a driving mechanism in accordance with a state of the substrate placed on the placement table is included.

9. The liquid processing method according to claim 8, wherein: a process of forming a ring-shaped film locally covering the peripheral portion on the back surface of the substrate is included, the state of the substrate refers to a position of an end portion of the ring-shaped film closer to the center of the substrate.

10. A fluid treatment device characterized by, Comprising: a placement table for placing a center portion of the back surface of a substrate; a rotating mechanism for rotating the placement table; and a nozzle for supplying a treatment liquid in mist form to a position closer to the center than the periphery of the back surface of the substrate being rotated, causing the treatment liquid to volatilize so that the treatment liquid is not supplied to the periphery of the substrate by centrifugal force, thereby locally processing a ring-shaped region of the back surface of the substrate, The length of the projection area projected on the substrate by the release opening of the nozzle in a radial direction of the substrate is smaller than the length of the projection area in a direction orthogonal to the radial direction.

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