Coating treatment method

Abstract

To accurately form a coating film on a side surface of a peripheral part of a substrate.SOLUTION: A coating processor for coating a peripheral part of a substrate with coating liquid has: a holding rotation part holding and rotating the substrate; a coating liquid supply nozzle supplying the peripheral part of the substrate held by the holding rotation part with the coating liquid; a movement mechanism moving the coating liquid supply nozzle; and a control part controlling the holding rotation part, the coating liquid supply nozzle, and the movement mechanism. The control part is configured to perform control of, by controlling the movement mechanism, moving the coating liquid supply nozzle from outside a periphery of the substrate to a prescribed position of a peripheral edge on the substrate at a first speed while supplying coating liquid with the coating liquid supply nozzle, rotating the holding rotation part held by the substrate, and then while supplying coating liquid with the coating liquid supply nozzle, by controlling the movement mechanism, moving the coating liquid supply nozzle from the prescribed position to outside the periphery of the substrate at a second speed faster than the first speed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a coating process method Regarding. [Background technology]

[0002] BACKGROUND ART Conventionally, a process of applying a coating liquid to the peripheral edge of a substrate such as a semiconductor wafer (hereinafter, sometimes simply referred to as a wafer) has been carried out.

[0003] In this regard, Patent Document 1 describes a peripheral edge coating device including a rotation holding unit that horizontally holds and rotates a circular substrate, a nozzle that supplies a coating liquid to form a coating film on the peripheral edge of the substrate, a movement mechanism that moves the nozzle to move the supply position of the coating liquid between the peripheral edge of the substrate and a position outside the substrate, and a control unit that outputs a control signal to control the rotation of the substrate by the rotation holding unit, the discharge of the coating liquid from the nozzle, and the movement of the nozzle by the movement mechanism. While rotating the substrate and supplying the coating liquid from the nozzle, the control unit moves the supply position of the coating liquid from the outside of the substrate toward the peripheral edge of the substrate, applying the coating liquid to a wedge-shaped area with an angle of 10° or less when viewed from above. Next, while continuing to rotate the substrate and supply the coating liquid, the control unit stops the movement of the nozzle and applies the coating liquid in a band along the peripheral edge of the substrate, and outputs a control signal so that the edge of the band-shaped coating liquid comes into contact with the coating liquid applied to the wedge-shaped area, thereby coating the coating liquid around the entire circumference of the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-62436 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology according to the present disclosure forms a coating film on the side surface of the peripheral edge of a substrate with high precision. [Means for solving the problem]

[0006] One aspect of the present disclosure is a coating process for applying a coating liquid to a peripheral portion of a substrate. method And, While rotating the substrate, a coating liquid is supplied from a coating liquid supply nozzle, and the coating liquid supply nozzle is moved at a first speed from outside the periphery of the substrate to a predetermined position on the periphery of the substrate. Thereafter, while supplying the coating liquid from the coating liquid supply nozzle, the coating liquid supply nozzle is moved at a second speed from the predetermined position to outside the periphery of the substrate. After the coating liquid supply nozzle has moved in the direction of the outer edge of the substrate, the rotation speed of the substrate is set so that a protective film of the coating liquid is formed in an area of ​​60 to 80% from the upper end of the edge surface of the peripheral edge side of the substrate. do. [Effects of the Invention]

[0007] According to the present disclosure, a coating film can be formed with high precision on the side surface of the peripheral edge portion of a substrate. [Brief explanation of the drawings]

[0008] [Figure 1] 10A and 10B are explanatory views showing a state in which a protective film is formed on the peripheral edge of a wafer. [Figure 2] FIG. 10 is an explanatory diagram showing a state in which a protective liquid is attached to the inner rim of a cup. [Figure 3] 1 is a side cross-sectional view illustrating a schematic configuration of a coating treatment apparatus according to an embodiment; [Figure 4] 1 is a plan view illustrating a schematic configuration of a coating treatment apparatus according to an embodiment; [Figure 5] 5A to 5C are explanatory views showing the movement of a nozzle in the coating method according to the embodiment. [Figure 6] 10 is an explanatory diagram showing how resist liquid splashes when the nozzle scans out from the wafer. FIG. [Figure 7]FIG. 10 is an explanatory diagram showing a state in which a protective film is formed up to the underside of the peripheral edge of the wafer. [Figure 8] FIG. 10 is an explanatory diagram showing a state in which a protective film is formed only on the upper side of the peripheral edge of the wafer. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the manufacturing process of semiconductor devices, a series of photolithography steps are performed, including a resist coating process in which a resist solution is supplied onto a wafer to form a resist film, thereby forming a predetermined resist pattern on the wafer. The series of steps described above is performed in a coating and developing processing system equipped with various liquid processing devices for processing the wafer, heat processing devices, and a transport device for transporting the wafer. Furthermore, after the photolithography process, the wafer may then be subjected to an etching process or the like, and the series of photolithography steps may be performed again.

[0010] In such a process, a coating process may be performed to form a protective film on the peripheral edge of the wafer in order to protect the peripheral edge during the etching process. This will be described in detail with reference to Figure 1. As shown in the figure, the peripheral edge of the wafer W is roughly divided into zone Z1, which is a flat upper surface, zone Z2, which is a sloped surface continuing from zone Z1, zone Z3, which is a vertical side edge (peripheral edge side edge) continuing from zone Z2, zone Z4, which is a sloped surface continuing from zone Z3, and zone Z5, which is a flat lower surface continuing from zone Z4.

[0011] A protective film P is formed on zones Z1, Z2, and Z3, which do not have a resist pattern during etching and are therefore susceptible to damage by the etchant. As the protective film P, for example, a resist film made of a resist liquid is used.

[0012] Such peripheral coating processing has conventionally been performed by a peripheral coating processing apparatus. Specifically, while the wafer is rotated by a holding / rotating unit such as a spin chuck that holds the wafer, a protective liquid supply nozzle N that forms a protective film, as shown in Figure 2, is moved from the outer periphery of the wafer W toward the center of the wafer W while discharging the protective liquid, and is stopped at the end of the coating area toward the center of the wafer W, and then the protective liquid supply nozzle N is retracted again toward the outer periphery of the wafer W. In this way, a protective film P is formed in zones Z1, Z2, and Z3 on the peripheral edge of the wafer W, as shown in Figure 1.

[0013] Then, in order to form the protective film P in a desired region of the zone Z3, for example, 60% to 80% of the region from the top end, the rotation speed of a holding rotation unit such as a spin chuck is adjusted.

[0014] Incidentally, a cup C shown in FIG. 2 is disposed outside a holding / rotating part such as a spin chuck. As described above, when forming a protective film in a desired region of zone Z3, if the holding / rotating part is rotated at high speed, the protective liquid splashes onto the edge of the cup C, particularly onto the inner surface of a block body provided on the edge of the cup C, as will be described later, and it has been found that contamination D caused by the protective liquid adheres to the inner surface of the edge of the cup C.

[0015] Therefore, the technology disclosed herein prevents the protective liquid from adhering to the inner edge of the cup when applying a coating liquid to the peripheral edge of a substrate such as a wafer, and accurately forms a protective film on the side surface of the peripheral edge.

[0016] Hereinafter, the present embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0017] FIG. 3 is a schematic cross-sectional side view of a coating processing apparatus 1 according to an embodiment, and FIG. 4 is a schematic plan view of the same. The coating processing apparatus 1 is configured as an apparatus for applying a protective liquid, such as a resist liquid, to the peripheral edge of a wafer W to form a protective film. The coating processing apparatus 1 includes a spin chuck 10 as a holding and rotating unit. The spin chuck 10 is configured to horizontally hold the wafer W, which is a circular substrate having a diameter of, for example, 300 mm, by vacuum suction. The spin chuck 10 is connected to a rotation drive unit 11 including a motor and the like. The rotation drive unit 11 rotates the spin chuck 10 vertically at a rotation speed corresponding to a control signal output from a control unit 100, which will be described later.

[0018] The wafer W is transferred to and from the spin chuck 10 by raising and lowering three support pins 12 (only two are shown in the figure for convenience of illustration) that support the backside of the wafer W. The support pins 12 are provided on a base 13, and the base 13 can be raised and lowered by driving an elevation mechanism 14.

[0019] A guide ring 20 having a mountain-shaped cross section is provided below the spin chuck 10, and an annular outer peripheral wall 21 is provided on the outer peripheral edge of the guide ring 20, extending downward. A cup 22 is arranged to surround the spin chuck 10 and the guide ring 20. That is, the cup 22 has a circular opening at the top and is configured to surround the wafer W held by the spin chuck 10. A cylindrical block body 22a is provided on the inner edge of the top of the cup 22. The block body 22a has the function of preventing mist from being released to the outside and of properly guiding the downflow into the cup 22.

[0020] As described above, the cup 22 is open at the top so that the wafer W can be transferred to the spin chuck 10. A gap 23 forming a discharge path is formed between the inner peripheral surface of the cup 22 and the outer peripheral wall 21 of the guide ring 20. An exhaust pipe 24 standing upright from the bottom 22b is provided at the bottom 22b of the cup 22. A drain port 25 is also provided at the bottom 22b of the cup 22.

[0021] The coating processing apparatus 1 is provided with a nozzle 30 serving as a coating liquid supply nozzle that supplies a protective liquid (coating liquid). The nozzle 30 has a discharge port 30a formed on its lower end surface. The nozzle 30 is connected to a resist liquid supply source 32 that stores the resist liquid via a resist liquid supply pipe 31. The resist liquid supply source 32 is provided with a pump, and pressure-feeds the resist liquid toward the nozzle 30, and the pressure-feed resist liquid is discharged from the discharge port 30a. The resist liquid supply pipe 31 is provided with a supply device group 33 including a valve, a flow rate adjuster, etc., and the supply, stop, and amount of the resist liquid supplied to the nozzle 30 are controlled based on control signals output from the control unit 100.

[0022] As shown in Fig. 4, the nozzle 30 is supported by an arm 41 extending horizontally. For convenience of illustration, the nozzle 30 is supported vertically in Fig. 3, but in reality, as shown in Fig. 5 described below, the nozzle 30 is disposed at a predetermined angle, for example, about 30 degrees, in a plan view relative to the tangential direction of the wafer W, and is directed toward the outside of the wafer W. Furthermore, the nozzle 30 is disposed at a predetermined angle, for example, about 30 degrees, rather than perpendicular to the horizontal plane of the wafer W. The angle at which the nozzle 30 is disposed can be determined within any range.

[0023] Nozzle 30 is connected to a moving mechanism 42 via an arm 41. Moving mechanism 42 moves along guide rails 43 extending laterally, and can raise and lower arm 41. Moving mechanism 42 moves in accordance with a control signal from control unit 100, and this movement of moving mechanism 42 allows nozzle 30 to move between a standby position 44 provided outside cup 22 and the periphery of wafer W. The moving distance, moving speed, and moving direction of moving mechanism 42 are also controlled by control signals from control unit 100.

[0024] The coating treatment apparatus 1 having the above configuration is controlled by the control unit 100 as described above. The control unit 100 is configured by a computer including, for example, a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores programs for controlling various processes in the coating treatment apparatus 1. The programs may be recorded on a computer-readable storage medium H and installed into the control unit 100 from the storage medium. The storage medium H may be temporary or non-temporary.

[0025] Next, an example of a coating method using the coating processing apparatus 1 configured as described above will be described. First, the wafer W is suction-held on the spin chuck 10, and the rotation driver 11 rotates the wafer W. The nozzle 30 is then moved toward the center of the wafer W from the standby position 44 shown in FIG. 3 described above. As shown in FIG. 5(a), the nozzle 30 begins discharging the resist solution inside the cup 22 and outside the periphery of the wafer W, more specifically, at a position between the inner circumferential surface of the block body 22a of the cup 22 and the outer edge of the wafer W. In this state, the nozzle 30 is moved to a predetermined position on the periphery of the wafer W at a first speed, e.g., 1 to 10 mm / sec (scan-in). Here, the predetermined position is a position where the desired radial width of the protective film to be formed with the resist solution can be achieved. The width of this protective film is set depending on the characteristics and properties of the protective film to be formed and the type of subsequent etching process, and is, for example, approximately 1 to 5 mm.

[0026] 5(b), when the nozzle 30 reaches a predetermined position, it is stopped. The resist solution continues to be discharged from the nozzle 30 while the wafer W rotates, for example, one to five times. As a result, a protective film P made of the resist solution is formed on the peripheral edge of the wafer W with the aforementioned width.

[0027] 5(c), the nozzle 30 is moved (scanned out) from the predetermined position in FIG. 5(b) toward the outside of the periphery of the wafer W at a second speed faster than the first speed, for example, a speed exceeding 50 mm / sec, preferably a speed of 80 to 200 mm / sec. Thereafter, the discharge of the resist liquid is stopped, and the nozzle 30 is then moved to the standby position 44.

[0028] In this way, by discharging the resist liquid onto the peripheral edge of the wafer W, a protective film P is formed in zones Z1, Z2, and Z3 on the peripheral edge of the wafer W, as shown in Fig. 1. It was confirmed that the contaminant D adhering to the inner surface of the edge of the cup C, as seen in the conventional method and shown in Fig. 2, does not occur. More specifically, it was confirmed that the protective liquid does not splash onto the inner surface of the block body 22a, causing the contaminant D to occur on the inner surface of the block body 22a. The deposition of resist liquid on the block body 22a and the resulting contamination D may indicate that the resist liquid has splashed beyond the block body 22a onto the outer surface of the cup 22. Furthermore, the resist liquid PL that splashed onto the inner circumferential surface of the block body 22a may collide with the inner circumferential surface and bounce back onto the wafer W, potentially adhering to areas where the resist liquid was not applied. The risk of such splashing increases as the resist liquid adheres and accumulates on the inner circumferential surface of the block body 22a. While the inner surface of the cup 22 can be cleaned with a cleaning liquid such as a solvent, cleaning the block body 22a is difficult. Therefore, suppressing or preventing the splashing of the protective liquid on the inner circumferential surface of the block body 22a can solve these problems.

[0029] The inventors conducted various experiments and found that, conventionally, the nozzle 30 moved at the same speed when it was moved to a predetermined position (during scan-in) as it moved from the predetermined position outward from the periphery of the wafer W (during scan-out). It was also found that, when the nozzle 30 moved to the predetermined position (during scan-in), the protective liquid did not adhere to the inner surface of the edge of the cup 22, but when the nozzle 30 moved from the predetermined position outward from the periphery of the wafer W (during scan-out), the protective liquid adhered to the inner surface of the edge of the cup 22.

[0030] Furthermore, when we investigated the cause of the protective liquid adhering to the inner surface of the edge of the cup C and the inner peripheral surface of the block body 22a, we confirmed that the protective liquid adheres to the inner surface of the edge of the cup C when a protective film P has already been formed on the upper peripheral surface of the wafer W and when resist liquid PL is further ejected on top of that, the ejected resist liquid PL collides with the protective film P that is not completely dry, causing the resist liquid PL to splash out with great force. Therefore, by shortening the time during which the resist liquid PL splashes out due to such collision as much as possible, the amount of protective liquid that splashes and adheres to the inner surface of the edge of the cup 22 and the inner peripheral surface of the block body 22a can be reduced accordingly.

[0031] Therefore, as in the above-described embodiment, by making the speed of the nozzle 30 during scanning out faster than the speed of the nozzle 30 during scanning out, the time during which the ejected resist liquid PL collides with the protective film P that is not completely dry can be shortened, thereby preventing the splashed resist liquid PL from adhering to the inner surface of the edge of the cup 22, particularly the inner surface of the block body 22a.

[0032] 1, this type of protective film P needs to be formed in zones Z1, Z2, and Z3 on the periphery of the wafer W, and the formation area in zone Z3 preferably covers 60 to 80% of the area from the top end. Such formation area is controlled by the rotation speed of the wafer W while the resist liquid, which is the protective liquid, is being discharged by the nozzle 30.

[0033] For example, if the rotation speed of the wafer W becomes too low, the protective film P will reach not only zone Z3 but also zone Z4, causing problems with subsequent transport and processing, as shown in Fig. 7. On the other hand, if the rotation speed of the wafer W becomes too high, the protective film P may not reach zone Z3 and may only cover zones Z1 and Z2, as shown in Fig. 8, which defeats the original purpose of the protective film P, which is to protect zone Z3 during the etching process.

[0034] Therefore, it is important to control the rotation speed of the wafer W when the protective liquid is discharged, but simply focusing on and controlling the rotation speed of the wafer W may result in the resist liquid PL scattered during scan-out adhering to the inner periphery of the edge of the cup 22 or the inner periphery of the block body 22 a, as described above. Therefore, it has been an extremely difficult problem to arbitrarily control the rotation speed of the wafer W when the protective liquid is discharged, while also preventing the protective liquid PL from adhering to the inner periphery of the cup 22, particularly the inner periphery of the block body 22 a.

[0035] As described above, in the technology of the present disclosure, by making the speed of the nozzle 30 during scan-out faster than the speed during scan-in, it is possible to prevent the protective liquid from adhering to the inner periphery of the cup 22, particularly the inner circumferential surface of the block body 22a, and therefore it is possible to focus only on controlling the region in which the protective film P is formed in zone Z3 and arbitrarily control the rotation speed of the wafer W. Therefore, the technology of the present disclosure can accurately form a coating film on the side surface of the peripheral edge of the substrate and prevent the resist liquid PL from adhering to the inner periphery of the cup, particularly the inner circumferential surface of the block body 22a.

[0036] According to the inventors' findings, by maintaining the rotation speed of the wafer W at 500 rpm or higher, preferably 800 rpm to 2000 rpm, in combination with the movement speed of the nozzle 30 during scan-out, the formation area of ​​the protective film P in the zone Z3 at the periphery of the wafer W can be kept within the range of 60 to 80%, and further, the resist liquid PL, which is the protective liquid, can be appropriately prevented from adhering to the inner edge of the cup 22.

[0037] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0038] For example, the following configuration is also proposed in this disclosure. (1) A coating treatment apparatus that applies a coating liquid to a peripheral portion of a substrate, a holding and rotating unit that holds and rotates the substrate; a coating liquid supply nozzle that supplies a coating liquid to a peripheral portion of the substrate held by the holding and rotating unit; a moving mechanism that moves the coating liquid supply nozzle; a control unit that controls the holding and rotating unit, the coating liquid supply nozzle, and the movement mechanism, The control unit rotates the holding and rotating unit that holds the substrate, while supplying a coating liquid from the coating liquid supply nozzle, controlling the movement mechanism to move the coating liquid supply nozzle from outside the periphery of the substrate to a predetermined position on the periphery of the substrate at a first speed; Thereafter, while supplying the coating liquid from the coating liquid supply nozzle, the coating processing apparatus is configured to control the movement mechanism to move the coating liquid supply nozzle from the predetermined position toward the outside of the periphery of the substrate at a second speed that is faster than the first speed. (2) The coating treatment device according to (1) above, wherein the second speed is a speed exceeding 50 mm / sec. (3) The coating treatment device according to (1), wherein the rotation speed of the holding and rotating part is 500 rpm or more. (4) The coating treatment apparatus according to (1) above, wherein the second speed is a speed exceeding 50 mm / sec, and the rotation speed of the holding rotation unit is 500 rpm or more. (5) The coating treatment device according to (4), wherein the rotation speed of the holding rotation part is 800 rpm to 2000 rpm. (6) A coating method for coating a coating liquid on a peripheral portion of a substrate, comprising: While rotating the substrate, a coating liquid is supplied from a coating liquid supply nozzle, and the coating liquid supply nozzle is moved at a first speed from outside the periphery of the substrate to a predetermined position on the periphery of the substrate; Thereafter, the coating liquid supply nozzle is moved from the predetermined position toward the outside of the periphery of the substrate at a second speed that is faster than the first speed while the coating liquid is being supplied by the coating liquid supply nozzle. (7) The coating method according to (6) above, wherein the second speed is a speed exceeding 50 mm / sec. (8) The coating method according to (6) above, wherein the rotation speed of the substrate is 500 rpm or more. (9) The coating method according to (6) above, wherein the second speed exceeds 50 mm / sec, and the rotation speed of the holding rotation unit is 500 rpm or higher. (10) The coating treatment method according to (9) above, wherein the rotation speed of the holding and rotating part is 800 rpm to 2000 rpm. (11) A readable computer storage medium storing a program that runs on a computer of a control unit that controls a coating processing device to execute a coating processing method for applying a coating liquid to a peripheral portion of a substrate, the program comprising: The coating treatment device includes: a holding and rotating unit that holds and rotates the substrate, a coating liquid supply nozzle that supplies a coating liquid to a peripheral edge portion of the substrate held by the holding and rotating unit, and a movement mechanism that moves the coating liquid supply nozzle, The coating treatment method includes: While rotating the substrate, a coating liquid is supplied from the coating liquid supply nozzle, and the coating liquid supply nozzle is moved at a first speed from outside the periphery of the substrate to a predetermined position on the periphery of the substrate; Thereafter, while supplying the coating liquid from the coating liquid supply nozzle, the coating liquid supply nozzle is moved from the predetermined position toward the outside of the periphery of the substrate at a second speed that is faster than the first speed. Computer storage media. (12) The computer storage medium according to (11), wherein the second speed is greater than 50 mm / sec. (13) The computer storage medium according to (11), wherein the rotation speed of the substrate is 500 rpm or more. [Explanation of symbols]

[0039] 1 Coating treatment equipment 10 Spin chuck 11 Rotation drive unit 12 Support pin 13 Foundation 14 Lifting mechanism 20 Guide Ring 21 Outer wall 22 cups 22a Block Letters 23 Gap 24 Exhaust pipe 25 drain port 30 nozzles 30a outlet 31 Resist liquid supply pipe 32 Resist liquid supply source 33 Supply equipment group 41 Arm 42 Moving mechanism 43 Guide rail 100 control section H storage medium P protective film PL resist liquid W wafer Z1~Z5 Zones

Claims

1. A coating processing method for applying a coating liquid to a peripheral portion of a substrate, comprising: While rotating the substrate, a coating liquid is supplied from a coating liquid supply nozzle, and the coating liquid supply nozzle is moved at a first speed from outside the periphery of the substrate to a predetermined position on the periphery of the substrate; Thereafter, while supplying the coating liquid from the coating liquid supply nozzle, the coating liquid supply nozzle is moved from the predetermined position toward the outside of the periphery of the substrate at a second speed; a rotation speed of the substrate is set so that, after the coating liquid supply nozzle is moved in the outer periphery direction of the substrate, a protective film of the coating liquid is formed over an area of ​​60 to 80% from the upper end of the peripheral edge side end face of the substrate.

2. The coating processing method according to claim 1 , wherein the second speed is greater than 50 mm / sec.

3. 2. The coating processing method according to claim 1, wherein the rotation speed of the substrate is 500 rpm or more.

4. 2. The coating processing method according to claim 1, wherein the second speed exceeds 50 mm / sec, and the rotation speed of the substrate is 500 rpm or higher.

5. 5. The coating processing method according to claim 4, wherein the rotation speed of the substrate is 800 rpm to 2000 rpm.

Images