JP2024014249A - Substrate processing method and substrate processing device - Google Patents

Abstract

To provide a substrate processing method and a substrate processing device, capable of causing an ultrasonic wave to act on a necessary area without damaging a pattern.SOLUTION: A substrate processing method includes: opening a pressurized valve 36 and pushing out a processing liquid from a discharge port 32 of an ultrasonic nozzle 30 to form a droplet D1 of the processing liquid; bringing the formed droplet D1 of the processing liquid into contact with a processing area P1 that is a part of an edge of a substrate W; and applying, from an ultrasonic vibrator 33, an ultrasonic wave to the droplet D1 brought into contact with the processing area P1. While ultrasonic cleaning can be performed to the processing area P1 by causing an ultrasonic wave to act on the processing area, the processing liquid does not come in contact with an area other than the processing area P1 and the ultrasonic wave does not act on the area other than the processing area P1. A pattern is formed in the area other than the processing area P1 that is a part of the edge. Accordingly, the ultrasonic wave does not act on the pattern, and acts on a necessary area while the pattern is prevented from being damaged.SELECTED DRAWING: Figure 8

Description

The present invention relates to a substrate processing method and a substrate processing apparatus for performing substrate processing such as cleaning or etching on a part of a processing area of a substrate. Substrates to be processed include, for example, semiconductor substrates, liquid crystal display substrates, flat panel display (FPD) substrates, optical disk substrates, magnetic disk substrates, solar cell substrates, and the like.

2. Description of the Related Art Conventionally, in the manufacturing process of semiconductor devices, substrate processing apparatuses have been used to perform various processes on semiconductor substrates (hereinafter simply referred to as "substrates"). As one such substrate processing apparatus, an ultrasonic cleaning apparatus is known that removes particles by supplying a cleaning liquid to a substrate with ultrasonic waves (for example, Patent Document 1).

A substrate cleaning device that performs such ultrasonic cleaning (for example, megasonic cleaning) discharges a cleaning liquid to which ultrasonic waves are applied to the surface of the substrate to be cleaned, and removes particles attached to the surface to be cleaned due to cavitation generated in the cleaning liquid. and other contaminants. Cavitation is a phenomenon in which bubbles are generated and disappear in a liquid in a short period of time due to pressure changes acting on the liquid. Ultrasonic cleaning removes particles and the like using a large impact generated when bubbles disappear, and has greater particle removal performance than cleaning that simply supplies cleaning liquid.

Japanese Patent Application Publication No. 2000-133626

One of the major problems with ultrasonic cleaning is that the patterns formed on the substrate are destroyed by cavitation. In other words, the impact caused by cavitation acts not only on particles but also on patterns, causing damage. As the cavitation intensity increases, the particle removal performance increases, but the damage to the pattern also increases. In particular, in recent years, the development of fragile patterns with large aspect ratios has progressed, and such fragile patterns are easily destroyed by ultrasonic cleaning.

Furthermore, in conventional ultrasonic cleaning, the cleaning liquid is supplied to the entire surface of the substrate, so the amount of cleaning liquid used must be large. From the perspective of SDGs (Sustainable Development Goals), the large amount of liquid consumed is also a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate processing method and a substrate processing apparatus in which ultrasonic waves can be applied to necessary areas without damaging a pattern.

In order to solve the above problem, the invention of claim 1 provides a substrate processing method for performing predetermined substrate processing on a part of the processing area of the substrate, including a holding step of holding the substrate, and a step of holding the substrate from the discharge port of the ultrasonic nozzle. A droplet forming step of extruding a treatment liquid to form droplets and bringing the droplets into contact with the treatment region of the substrate; and an ultrasound application step of applying ultrasound to the droplets brought into contact with the treatment region. and a suction step of suctioning the droplet brought into contact with the processing area.

Further, the invention of claim 2 is the substrate processing method according to the invention of claim 1, further comprising an inert gas blowing step of blowing an inert gas onto the processing area when the droplet is in contact with the substrate. It is characterized by being prepared.

A third aspect of the present invention is the substrate processing method according to the second aspect of the present invention, wherein in the inert gas blowing step, an inert gas is sprayed from the center of the substrate toward the outer peripheral edge.

Further, the invention according to claim 4 is characterized in that the substrate processing method according to any one of claims 1 to 3 further comprises a nozzle cleaning step of cleaning the ultrasonic nozzle in a nozzle cleaning tank. do.

Further, the invention according to claim 5 is the substrate processing method according to any one of claims 1 to 4, characterized in that the inner diameter of the discharge port is 0.5 mm or more and 1.0 mm or less.

Further, the invention according to claim 6 provides a substrate processing apparatus that performs predetermined substrate processing on a part of the processing area of the substrate, which includes a substrate holding section that holds the substrate, and a processing liquid that is extruded from a discharge port to form droplets. an ultrasonic nozzle for forming and applying ultrasonic waves to the droplets; and a nozzle drive mechanism for moving the ultrasonic nozzle; is brought into contact with the processing area of the substrate held by the substrate holder, and after applying ultrasonic waves to the droplets, the droplets are sucked.

The invention of claim 7 is the substrate processing apparatus according to the invention of claim 6, further comprising an inert gas jetting section that sprays an inert gas onto the processing area when the droplet is in contact with the substrate. It is characterized by being prepared.

Further, an eighth aspect of the present invention is the substrate processing apparatus according to the seventh aspect of the present invention, wherein the inert gas blowing section blows the inert gas from the center of the substrate toward the outer peripheral edge.

The invention according to claim 9 is characterized in that the substrate processing apparatus according to any one of claims 6 to 8 further includes a nozzle cleaning tank for cleaning the ultrasonic nozzle.

Moreover, the invention of claim 10 is characterized in that, in the substrate processing apparatus according to any one of claims 6 to 9, the inner diameter of the discharge port is 0.5 mm or more and 1.0 mm or less.

According to the invention of claims 1 to 5, the processing liquid is extruded from the discharge port of the ultrasonic nozzle to form droplets, the droplets are brought into contact with the processing area of the substrate, and the contacted droplets are subjected to ultraviolet rays. Since the sound waves are applied, the processing liquid does not come into contact with areas other than the processing area, and the ultrasonic waves do not act on the area, so the ultrasonic waves can be applied to the necessary areas without damaging the pattern.

In particular, according to the invention of claim 2, since the inert gas is sprayed onto the processing area when the droplet is in contact with the substrate, the processing area is blocked from oxygen and watermarks are prevented from forming on the processing area. can do.

In particular, according to the third aspect of the invention, since the inert gas is sprayed from the center of the substrate toward the outer peripheral edge, it is possible to prevent the processing liquid from flowing toward the inner region of the substrate where the pattern is formed. can.

According to the invention of claims 6 to 10, the droplets of the processing liquid formed at the discharge port of the ultrasonic nozzle are brought into contact with the processing area of the substrate and ultrasonic waves are applied to the droplets. The processing liquid does not come into contact with areas other than those areas, and the ultrasonic waves do not act on any areas other than those areas, so the ultrasonic waves can be applied to necessary areas without damaging the pattern.

In particular, according to the invention of claim 7, since the inert gas is sprayed onto the processing area when the droplet is in contact with the substrate, the processing area is blocked from oxygen and watermarks are prevented from forming on the processing area. can do.

In particular, according to the invention of claim 8, since the inert gas is sprayed from the center of the substrate toward the outer peripheral edge, it is possible to prevent the processing liquid from flowing toward the inner region of the substrate where the pattern is formed. can.

FIG. 1 is a plan view of a substrate processing apparatus according to the present invention. FIG. 2 is a side view showing the configuration of main parts of the substrate processing apparatus. It is a figure showing the composition of an ultrasonic nozzle. FIG. 3 is a diagram showing the configuration of a nozzle cleaning tank. 3 is a flowchart showing an operating procedure in the substrate processing apparatus. FIG. 3 is a diagram showing a state in which an ultrasonic nozzle is located directly above a processing area of a substrate. FIG. 6 is a diagram showing a state in which droplets of processing liquid are formed at the discharge port of the ultrasonic nozzle. FIG. 3 is a diagram showing a state in which a droplet of a processing liquid is in contact with a processing region of a substrate. FIG. 6 is a diagram showing a state in which an ultrasonic nozzle sucks a droplet that has been brought into contact with a processing region.

Embodiments of the present invention will be described in detail below with reference to the drawings. In the following, expressions indicating relative or absolute positional relationships (for example, "in one direction", "along one direction", "parallel", "orthogonal", "centered", "concentric", "coaxial") , etc.), unless otherwise specified, not only strictly represent their positional relationship, but also represent a state in which they are relatively displaced in terms of angle or distance within a range that allows tolerance or equivalent functionality to be obtained. Furthermore, unless otherwise specified, expressions indicating equal conditions (e.g., "same," "equal," "homogeneous," etc.) do not only refer to quantitatively strictly equal conditions, but also to tolerances or the same condition. It also represents a state in which there is a difference in the degree of function obtained. Furthermore, unless otherwise specified, expressions that indicate shapes (e.g., "circular shape," "square shape," "cylindrical shape," etc.) do not only strictly represent the shape geometrically; It represents the shape of the range in which the effect can be obtained, and may have, for example, unevenness or chamfering. In addition, expressions such as "comprising," "comprising," "equipment," "containing," and "having" a component are not exclusive expressions that exclude the presence of other components. In addition, the expression "at least one of A, B, and C" includes "only A," "only B," "only C," "any two of A, B, and C," and " All of A, B and C" are included.

FIG. 1 is a plan view of a substrate processing apparatus 1 according to the present invention. Further, FIG. 2 is a side view showing the main part configuration of the substrate processing apparatus 1. As shown in FIG. The substrate processing apparatus 1 is a single-wafer type substrate processing apparatus that performs a cleaning process or an etching process on one substrate W using ultrasonic waves. The substrate W to be processed is a disk-shaped semiconductor substrate made of silicon. Note that in FIG. 1 and the subsequent figures, the dimensions and numbers of each part are exaggerated or simplified as necessary for easy understanding.

The substrate processing apparatus 1 mainly includes a processing chamber 10 , a rotation holding section 20 , an ultrasonic nozzle 30 , a nozzle cleaning tank 50 , and a control section 90 .

The processing chamber 10 is a hollow housing. Inside the processing chamber 10, the above-mentioned rotation holding section 20, ultrasonic nozzle 30, etc. are provided. During substrate processing, the processing chamber 10 accommodates a substrate W to be processed.

A fan filter unit (FFU) 12 is installed on the ceiling of the processing chamber 10 . The fan filter unit 12 includes a fan for blowing air and a filter (for example, a HEPA filter), and supplies clean air downward from the ceiling of the processing chamber 10 . That is, the fan filter unit 12 supplies clean air into the processing chamber 10 .

An exhaust pipe 18 is connected to the bottom of the processing chamber 10 . The exhaust pipe 18 is connected to an exhaust mechanism (for example, an exhaust pump), which is not shown. The air supplied from the fan filter unit 12 is discharged from the exhaust pipe 18, thereby forming a downflow of clean air inside the processing chamber 10.

Further, the processing chamber 10 is provided with a loading/unloading port (not shown). The loading/unloading entrance is opened and closed by a shutter. The substrate W is carried into and out of the processing chamber 10 while the carry-in/out port is open. The loading/unloading entrance is closed while the substrate W is being processed.

The rotation holding section 20 includes a spin chuck 22 and a spin motor 25. The spin chuck 22 is a substrate holder that holds the substrate W in a horizontal position (a position in which the normal to the main surface of the substrate W is along the vertical direction). The spin chuck 22 in this embodiment is a vacuum suction type chuck. The spin chuck 22 attracts and holds the center portion of the lower surface of the substrate W. Note that the spin chuck may be another type of chuck such as a clamping mechanical chuck.

The spin chuck 22 has a disk shape with a diameter smaller than the diameter of the substrate W. When the lower surface of the substrate W is suctioned and held by the spin chuck 22, the peripheral edge of the substrate W protrudes outside the outer peripheral end of the spin chuck 22.

The spin chuck 22 is connected to a spin motor 25 via a spin shaft 27. That is, the upper end of the spin shaft 27 of the spin motor 25 is connected to the center of the lower surface of the spin chuck 22 . When the spin motor 25 rotates the spin shaft 27 while the substrate W is held by the spin chuck 22, the substrate W and the spin chuck 22 rotate in a horizontal plane around the rotation axis A1 along the vertical direction. .

A cup 40 is provided to surround the spin chuck 22. The cup 40 has a cylindrical shape, and the upper part of the cup 40 is inclined so that it approaches the spin chuck 22 as it goes upward. However, the inner diameter of the upper end portion of the cup 40 is larger than the diameter of the substrate W. The upper end of the cup 40 is higher than the height of the substrate W held by the spin chuck 22. Therefore, the liquid scattered by the centrifugal force from the substrate W rotated by the spin motor 25 is received and collected by the cup 40. The liquid collected by the cup 40 is discharged from a drain pipe provided at the bottom of the cup 40. Note that the cup 40 may have a multi-stage structure in which a plurality of collection ports are provided for different purposes.

The ultrasonic nozzle 30 is attached to the tip of a rod-shaped nozzle arm 61 that extends in the horizontal direction. The nozzle arm 61 is supported by an arm support shaft 62 that extends in the vertical direction. The arm support shaft 62 is connected to a nozzle drive section 63. The nozzle drive unit 63 rotates the arm support shaft 62 around a rotation axis A2 along the vertical direction. When the nozzle drive unit 63 rotates the arm support shaft 62, the nozzle arm 61 performs a pivoting operation, and the ultrasonic nozzle 30 moves to a standby position outside the cup 40, as shown by arrow AR1 in FIG. It moves along an arcuate trajectory to and from a processing position above the substrate W held by the spin chuck 22.

Further, the nozzle drive section 63 moves the arm support shaft 62 and the nozzle arm 61 up and down. Thereby, the ultrasonic nozzle 30 also moves up and down along the vertical direction.

FIG. 3 is a diagram showing the configuration of the ultrasonic nozzle 30. The main body 31 of the ultrasonic nozzle 30 is composed of a hollow cylindrical upper main body 31a and a cylindrical lower main body 31b. The inner diameter of the upper body portion 31a is larger than the inner diameter of the lower body portion 31b. The connecting portion between the upper body portion 31a and the lower body portion 31b is a tapered surface.

The lower end of the lower body portion 31b is an open end, and the open end serves as the discharge port 32 of the ultrasonic nozzle 30. The inner diameter d of the discharge port 32 is 0.5 mm or more and 1.0 mm or less.

An ultrasonic transducer 33 is provided in the upper part of the inner space of the main body upper part 31a. High frequency power is supplied to the ultrasonic transducer 33 from a high frequency power source (not shown). The ultrasonic transducer 33 generates ultrasonic waves when high-frequency power is applied.

Further, a pressurizing pipe 34 and a suction pipe 35 are connected to the main body upper part 31a of the main body part 31 in communication. The distal end of the pressurizing tube 34 is connected to the main body upper part 31a, and the proximal end is connected to the processing liquid supply mechanism 71. A pressurizing valve 36 is provided in the middle of the pressurizing pipe 34 .

The processing liquid supply mechanism 71 includes a tank for storing the processing liquid, a pump, and the like. The processing liquid supply mechanism 71 supplies the processing liquid to the pressurizing pipe 34 at a predetermined pressure. In this specification, the term "processing liquid" is a conceptual term that includes various chemical solutions and pure water. The chemical solution includes, for example, a solution for etching or a solution for removing particles, and specifically, an SC-1 solution (ammonium hydroxide, hydrogen peroxide, and pure water (a mixed solution of hydrochloric acid, hydrogen peroxide, and pure water), SC-2 solution (a mixed solution of hydrochloric acid, hydrogen peroxide, and pure water), or hydrofluoric acid (HF). The chemical solution also includes one diluted with pure water. In this embodiment, the processing liquid supply mechanism 71 supplies pure water to the main body 31 as the processing liquid.

The pressurizing valve 36 opens and closes the flow path of the pressurizing pipe 34. While supplying the processing liquid from the processing liquid supply mechanism 71 to the pressurizing pipe 34, when the pressurizing valve 36 opens the flow path of the pressurizing pipe 34, the processing liquid is supplied into the main body 31 at a predetermined pressure (positive pressure). Ru. When the pressurizing valve 36 closes the flow path of the pressurizing pipe 34, the supply of the processing liquid to the main body 31 is stopped. Note that the opening or closing of the flow path of the pressurizing pipe 34 by the pressurizing valve 36 is also referred to as opening or closing of the pressurizing valve 36.

On the other hand, the distal end of the suction tube 35 is connected to the main body upper part 31a, and the base end is connected to the suction mechanism 72. A suction valve 37 is provided in the middle of the suction pipe 35 .

The suction mechanism 72 includes a pump that sucks liquid. The suction mechanism 72 suctions the processing liquid from the suction tube 35 at a predetermined pressure.

The suction valve 37 opens and closes the flow path of the suction pipe 35. When the suction mechanism 72 suctions the liquid from the suction tube 35 and the suction valve 37 opens the flow path of the suction tube 35, the processing liquid is suctioned from the main body 31 at a predetermined pressure (negative pressure). When the suction valve 37 closes the flow path of the suction pipe 35, suction of the processing liquid from the main body 31 is stopped. Note that opening or closing of the flow path of the suction pipe 35 by the suction valve 37 is also referred to as opening or closing of the suction valve 37.

Further, as shown in FIGS. 1 and 2, a support member 81 is attached to the nozzle arm 61, and an inert gas nozzle 82 is supported by the support member 81. Since both the ultrasonic nozzle 30 and the inert gas nozzle 82 are attached to the common nozzle arm 61, both perform the same movement operation while maintaining a fixed relative positional relationship. For example, when the ultrasonic nozzle 30 moves along an arcuate trajectory as indicated by arrow AR1 in FIG. 1, the inert gas nozzle 82 similarly moves along an arcuate trajectory.

As shown in FIG. 3, the inert gas nozzle 82 is connected to an inert gas supply source 83 via a pipe 85. A valve 84 is provided in the pipe 85. When the valve 84 is opened, inert gas (nitrogen (N ₂ ) in this embodiment) is supplied from the inert gas supply source 83 to the inert gas nozzle 82, and the inert gas nozzle 82 blows out the inert gas. . The inert gas nozzle 82 sprays inert gas directly below the discharge port 32 including the discharge port 32 of the ultrasonic nozzle 30 . Note that the inert gas ejected from the inert gas nozzle 82 may be helium (He) or argon (Ar).

The control unit 90 controls various operating mechanisms provided in the substrate processing apparatus 1 . The hardware configuration of the control unit 90 is similar to that of a general computer. That is, the control unit 90 includes a CPU, which is a circuit that performs various calculation processes, a ROM, which is a read-only memory that stores basic programs, a RAM, which is a readable and writable memory that stores various information, and control software and data. It includes a storage unit (for example, a magnetic disk or SSD) for storing data. The control unit 90 is electrically connected to the pressure valve 36, the suction valve 37, etc., and controls the operations thereof.

The nozzle cleaning tank 50 is provided outside the cup 40 and near the standby position of the ultrasonic nozzle 30 . FIG. 4 is a diagram showing the configuration of the nozzle cleaning tank 50. A cleaning liquid is stored in the nozzle cleaning tank 50. This cleaning liquid may be the same as the processing liquid used by the ultrasonic nozzle 30. When cleaning the ultrasonic nozzle 30, the vicinity of the discharge port 32 of the lower part 31b of the main body is immersed in a cleaning liquid.

A drying nozzle 55 is attached to the nozzle cleaning tank 50. The drying nozzle 55 blows air supplied from an air supply source (not shown) onto the ultrasonic nozzle 30 pulled up from the nozzle cleaning tank 50. As a result, the exterior surface of the ultrasonic nozzle 30 is dried.

Next, the operation of the substrate processing apparatus 1 will be explained. FIG. 5 is a flowchart showing the operating procedure in the substrate processing apparatus 1. First, before starting to process the substrate W, the ultrasonic nozzle 30 is cleaned (step S1). When the substrate W is not present in the processing chamber 10, the ultrasonic nozzle 30 is on standby at a standby position outside the cup 40. A nozzle cleaning tank 50 is provided at the standby position. When the ultrasonic nozzle 30 is waiting at the standby position, the ultrasonic nozzle 30 is cleaned in the nozzle cleaning tank 50. A state where the ultrasonic nozzle 30 is being cleaned at the standby position is referred to as a standby state of the ultrasonic nozzle 30.

Specifically, as shown in FIG. 4, the lower end portion of the lower main body 31b of the ultrasonic nozzle 30 is immersed in the cleaning liquid stored in the nozzle cleaning tank 50, and the outer wall surface near the discharge port 32 is cleaned. Furthermore, the pressurizing valve 36 is opened and cleaning liquid (pure water in this embodiment) is supplied into the main body 31 of the ultrasonic nozzle 30 . When cleaning the ultrasonic nozzle 30, the pressurizing valve 36 is continuously opened and cleaning liquid continues to be supplied into the main body 31. The cleaning liquid supplied to the main body part 31 is discharged from the discharge port 32 into the cleaning liquid stored in the nozzle cleaning tank 50. Therefore, during cleaning of the ultrasonic nozzle 30, the inside of the main body 31 of the ultrasonic nozzle 30 is filled with cleaning liquid, and the cleaning liquid is flowing toward the discharge port 32. Then, ultrasonic waves are applied from the ultrasonic vibrator 33 to the cleaning liquid filling the inside of the main body 31 . As a result, the inner wall surface of the main body portion 31 of the ultrasonic nozzle 30 is ultrasonically cleaned. Contaminants separated from the inner wall surface of the main body 31 by ultrasonic cleaning are discharged into the nozzle cleaning tank 50 from the discharge port 32 at the lower end of the main body 31 together with the cleaning liquid. In this way, both the inner wall surface and the outer wall surface of the main body portion 31 of the ultrasonic nozzle 30 are cleaned.

Next, when starting the processing of the substrate W, a transfer robot outside the apparatus carries the substrate W to be processed into the processing chamber 10 and causes it to be held by the spin chuck 22 (step S2). The spin chuck 22 attracts the center portion of the lower surface of the loaded substrate W and holds the substrate W in a horizontal position.

After the substrate W is held by the spin chuck 22, the ultrasonic nozzle 30 moves to a predetermined processing position (step S3). When the ultrasonic nozzle 30 in the standby state starts to move, the nozzle drive section 63 raises the ultrasonic nozzle 30 and pulls it upward from the nozzle cleaning tank 50. While pulling up the ultrasonic nozzle 30, dry air is blown from the drying nozzle 55 onto the outer wall surface of the main body 31 of the ultrasonic nozzle 30 (see FIG. 4). Thereby, the outer wall surface of the ultrasonic nozzle 30 is dried, and it is possible to prevent liquid from dripping onto the substrate W from the outer wall surface of the ultrasonic nozzle 30 during processing. Furthermore, when the ultrasonic nozzle 30 starts moving, the pressure valve 36 is closed and the supply of cleaning liquid to the ultrasonic nozzle 30 is stopped. Note that since the suction valve 37 continues to be closed, the inside of the main body 31 of the ultrasonic nozzle 30 is filled with pure water, but pure water is not discharged from the discharge port 32. Further, the ultrasonic transducer 33 also stops operating.

In this embodiment, a cleaning process is performed to remove particles attached to the outer edge of the substrate W (bevel cleaning). In step S3, under the control of the control unit 90, the spin motor 25 rotates the substrate W, and the ultrasonic nozzle 30 moves on a circular trajectory along which the ultrasonic nozzle 30 moves in the processing area (a part of the edge portion) to be cleaned. (see Figure 1). Further, under the control of the control unit 90, the nozzle drive unit 63 rotates the ultrasonic nozzle 30 to move it above the edge of the outer periphery of the substrate W. Thereby, as shown in FIG. 6, the discharge port 32 of the ultrasonic nozzle 30 is located directly above the processing area P1 of the substrate W. In this state, both the pressure valve 36 and the suction valve 37 are stopped, and the inside of the main body 31 of the ultrasonic nozzle 30 is quietly filled with the processing liquid (pure water), and the processing liquid is transferred from the ultrasonic vibrator 33 to the processing liquid. The application of ultrasonic waves has also been suspended. Further, the rotation of the substrate W and the movement of the ultrasonic nozzle 30 are stopped, and the state where the ultrasonic nozzle 30 is located directly above the processing area P1 is maintained.

Next, the processing liquid is extruded from the discharge port 32 of the ultrasonic nozzle 30 to form droplets of the processing liquid (step S4). At this time, under the control of the control unit 90, the pressure valve 36 is opened for a certain period of time while the suction valve 37 is closed. When the pressure valve 36 is opened while the suction valve 37 is closed, the processing liquid is supplied from the pressure pipe 34 at a predetermined pressure, the processing liquid in the main body 31 is pressurized, and the processing liquid is discharged from the discharge port 32. will be pushed out. If the pressure valve 36 is kept open, the processing liquid will be discharged (outflowed) from the discharge port 32, but if the pressure valve 36 is opened for a certain period of time and then closed, A certain amount of processing liquid is pushed out from the outlet 32, and the pushed out processing liquid forms droplets due to surface tension.

FIG. 7 is a diagram showing a state in which droplets of processing liquid are formed at the discharge port 32 of the ultrasonic nozzle 30. A certain amount of processing liquid is extruded from the discharge port 32 of the ultrasonic nozzle 30, and droplets D1 of the processing liquid are formed directly above the processing area P1 of the substrate W. The shape of the droplet D1 is maintained without falling from the discharge port 32 onto the substrate W due to the balance between the surface tension of the processing liquid and gravity. The surface tension of the treatment liquid is determined by the surface condition of the ultrasonic nozzle 30, the viscosity of the treatment liquid, the temperature of the treatment liquid, and the like. In other words, the opening time of the pressurizing valve 36 may be controlled so as to push out an amount of processing liquid that does not cause the droplet D1 to fall from the discharge port 32.

After the droplet D1 of the processing liquid is formed at the discharge port 32 of the ultrasonic nozzle 30, the droplet D1 is brought into contact with the substrate W (step S5). Specifically, the nozzle drive unit 63 gently lowers the ultrasonic nozzle 30 to bring the droplet D1 of the processing liquid formed in the discharge port 32 into gentle contact with the processing region P1 of the substrate W.

FIG. 8 is a diagram showing a state in which a droplet D1 of the processing liquid is in contact with the processing region P1 of the substrate W. When the droplet D1 of the processing liquid formed at the discharge port 32 of the ultrasonic nozzle 30 contacts the processing region P1 of the substrate W, a liquid column of the processing liquid is formed between the discharge port 32 and the substrate W. Ru. At this time, since the amount of the droplets D1 is not so large, the processing liquid does not spread over the surface of the substrate W. Note that the processing region P1 is a part of the edge of the substrate W, and the width of the edge is 1 mm to several mm, but the inner diameter d of the discharge port 32 of the ultrasonic nozzle 30 is 0.5 mm or more. Since it is 0 mm or less, the droplet D1 does not protrude from the processing area P1.

Further, almost at the same time that the droplet D1 of the processing liquid comes into contact with the processing region P1 of the substrate W, the ultrasonic vibrator 33 starts operating and generates ultrasonic waves. The ultrasonic wave generated from the ultrasonic transducer 33 propagates through the processing liquid filling the main body 31 and is applied to the droplet D1 in contact with the processing region P1 (step S6).

Ultrasonic cleaning is performed on the processing region P1 by applying ultrasonic waves to the droplets D1 of the processing liquid. Specifically, by applying ultrasonic waves to the droplet D1, cavitation occurs in the droplet D1. As mentioned above, cavitation is a phenomenon in which bubbles are generated and disappear in a liquid in a short period of time due to pressure changes acting on the liquid. Then, due to the large impact generated when the bubbles disappear, contaminants such as particles adhering to the processing area P1 are peeled off. In this way, ultrasonic cleaning of the processing area P1 of the substrate W proceeds.

Furthermore, when the ultrasonic nozzle 30 performs ultrasonic cleaning, nitrogen gas is sprayed from the inert gas nozzle 82 into the vicinity of the processing area P1 with which the droplet D1 is in contact (step S7). When the droplet D1 is in contact with the substrate W, by spraying nitrogen gas from the inert gas nozzle 82 onto the processing area P1 that the droplet D1 is in contact with, the area around the processing area P1 becomes a nitrogen atmosphere and is filled with oxygen. As a result, it is possible to prevent a watermark from being attached to the processing area P1. A watermark is a stain caused by the action of moisture and oxygen on the surface of the substrate W. By blowing nitrogen gas from the inert gas nozzle 82 to block oxygen from around the processing region P1, oxidation in the processing region P1 is prevented and water marks are prevented from occurring.

As mentioned above, since the amount of the processing liquid droplet D1 formed in step S4 is not so large, basically the processing liquid will not reach the surface of the substrate W even when the droplet D1 contacts the processing area P1. It will not spread further. However, depending on the wettability (contact angle) of the surface of the substrate W, there is a possibility that the processing liquid will spread over the surface of the substrate W when the droplet D1 contacts the processing region P1. Specifically, if the surface of the substrate W is hydrophilic (the contact angle is small), the processing liquid will easily spread over the surface of the substrate W. For this reason, the surface of the substrate W is preferably water repellent (has a large contact angle).

In this embodiment, an inert gas nozzle 82 is provided inside the ultrasonic nozzle 30 when viewed from the spin chuck 22, and the inert gas nozzle 82 sprays nitrogen gas from the center of the substrate W toward the outer peripheral edge. Therefore, even if the surface of the substrate W is hydrophilic and the processing liquid constituting the droplet D1 spreads over the surface of the substrate W, the processing liquid can be directed toward the outer peripheral end of the substrate W. As a result, the processing liquid is prevented from spreading to the inner region (inner region than the edge portion) of the substrate W on which the pattern is formed and contaminating the inner region.

After a predetermined period of time has elapsed since the start of ultrasonic cleaning with the droplet D1 in contact with the processing area P1, the ultrasonic nozzle 30 sucks the droplet D1 that has been in contact with the processing area P1 (step S8). FIG. 9 is a diagram showing a state in which the ultrasonic nozzle 30 sucks the droplet D1 brought into contact with the processing region P1. At this time, under the control of the control unit 90, the suction valve 37 is opened while the pressure valve 36 is closed. When the suction valve 37 is opened while the pressure valve 36 is closed, the processing liquid in the main body 31 is sucked into the suction tube 35, and the processing liquid in the discharge port 32 is also sucked, creating a negative pressure on the droplet D1. acts. As a result, the droplet D1 of the processing liquid that was in contact with the processing region P1 is separated from the processing region P1 and sucked into the main body portion 31 through the discharge port 32. At this time, particles separated from the processing area P1 due to ultrasonic cleaning are also sucked into the main body portion 31 through the discharge port 32 together with the droplet D1. That is, particles have been removed from the processing area P1 of the substrate W. Note that since the inside of the ultrasonic nozzle 30 will be cleaned later in the nozzle cleaning tank 50, it is not necessary to completely suck all the processing liquid in the main body part 31 from the suction tube 35, and the droplet D1 will be transferred to the lower part of the main body 31b. It is sufficient to open the suction valve 37 only for a period of time that allows suction.

After the droplet D1 is sucked into the ultrasonic nozzle 30, the ultrasonic nozzle 30 moves to the standby position again (step S9). That is, the control unit 90 controls the nozzle drive unit 63 to rotate the ultrasonic nozzle 30 and move it to the standby position.

The same cleaning process as in step S1 is performed on the ultrasonic nozzle 30 that has returned to the standby position. At this time, the particles sucked together with the droplet D1 in step S8 are discharged from the discharge port 32 of the ultrasonic nozzle 30 into the nozzle cleaning tank 50.

In this embodiment, the processing liquid is extruded from the discharge port 32 of the ultrasonic nozzle 30 to form a droplet D1 of the processing liquid, and the droplet D1 is brought into contact with the processing area P1 of the substrate W. is given ultrasound. Thereby, ultrasonic cleaning can be performed by applying ultrasonic waves to the processing region P1, and particles attached to the processing region P1 can be removed. On the other hand, the processing liquid does not come into contact with areas other than the processing area P1 (including the inner area of the substrate W on which the pattern is formed), and the ultrasonic waves do not act on the areas other than the processing area P1. Therefore, the ultrasonic waves do not act on the pattern, and it is possible to prevent the pattern from being damaged by cavitation caused by the ultrasonic waves. As a result, it is possible to apply ultrasonic waves only to the area that requires cleaning, and while performing appropriate ultrasonic cleaning on the area, it is possible to apply ultrasonic waves to the area where the pattern has been formed. This can prevent damage to the pattern. That is, ultrasonic waves can be applied to necessary areas without damaging the pattern. Note that since the processing area P1 is a part of the edge of the substrate W, no pattern is formed in the processing area P1. It is preferable to set the processing area P1 at a location where contamination is likely to occur due to contact of some member with the edge of the substrate W in the previous process.

Further, in this embodiment, the droplets D1 of the processing liquid are brought into contact with only the processing region P1, which is a part of the edge of the substrate W, and the processing liquid is not supplied to other regions. That is, the cleaning of this embodiment can be considered as pseudo-dry cleaning in which most areas on the substrate W do not come into contact with the processing liquid. Therefore, the amount of processing liquid consumed can be significantly reduced compared to conventional ultrasonic cleaning.

Further, in this embodiment, while the droplet D1 of the processing liquid is in contact with the substrate W, nitrogen gas is sprayed from the inert gas nozzle 82 into the vicinity of the processing region P1. Thereby, it is possible to block the processing region P1 from oxygen and prevent watermarks from being attached to the processing region P1.

In particular, the inert gas nozzle 82 sprays nitrogen gas from the center of the substrate W toward the outer peripheral edge. Therefore, it is possible to prevent the processing liquid from flowing from the droplet D1 in contact with the processing region P1 of the substrate W toward the inner region of the substrate W where a pattern is formed.

Further, in this embodiment, the inner diameter d of the discharge port 32 of the ultrasonic nozzle 30 is 0.5 mm or more and 1.0 mm or less. The width of the edge portion of the substrate W is 1 mm to several mm. Therefore, the droplet can be brought into contact only with the edge portion without contacting the inner region of the substrate W, and the edge portion can be cleaned well without damaging the pattern.

The embodiments of the present invention have been described above, but the present invention can be modified in various ways other than those described above without departing from the spirit thereof. For example, in the above embodiment, the processing area P1, which is a part of the edge portion, is cleaned while holding the substrate W in a stationary state, but instead of this, the substrate W is rotated by the spin motor 25. At the same time, the entire edge portion may be ultrasonically cleaned.

Further, in the above embodiment, the cleaning process is performed on the processing area P1 which is a part of the edge of the substrate W, but the cleaning process is not limited to this, and a part of the inner area is cleaned. A cleaning process may also be performed. Even in the inner region of the substrate W, a pattern is not formed over the entire area, and there are portions in the inner region where no pattern is formed. A droplet D1 of the processing liquid may be brought into contact with a region where such an inner region pattern does not exist, and ultrasonic waves may be applied to the droplet D1 to clean the region. Even in this case, as in the above embodiment, ultrasonic waves can be applied to necessary areas without damaging the pattern. That is, the technology according to the present invention is a local processing technology that processes not only the edge portion of the substrate W but also any arbitrary location within the plane of the substrate W in a limited manner.

Further, in the above embodiment, pure water is used as the processing liquid, but instead of this, a cleaning liquid such as SC-1 liquid may be used as the processing liquid. If ultrasonic cleaning is performed using a cleaning liquid such as SC-1 liquid, particles firmly attached to the substrate W can be removed more effectively.

Further, the substrate processing technology according to the present invention is not limited to cleaning processing, but may also be etching processing. Specifically, for example, an etching solution such as hydrofluoric acid may be used as the processing solution, and droplets of the etching solution may be brought into contact with a partial region of the substrate W to perform the etching process on the partial region. A predetermined thin film is formed on the surface of the substrate W. A droplet of an etching liquid is brought into contact with a partial region of the substrate W on which a thin film has been formed, and an ultrasonic wave is applied to the droplet to perform an etching process on the thin film in the partial region. In this way, since the etching liquid is heated by the ultrasonic waves, the etching rate can be improved. In addition, thin films can be effectively etched by the effect of cavitation.

Further, the substrate processing apparatus 1 is provided with a cleaning nozzle for discharging a cleaning liquid, and the cleaning process is performed by discharging the cleaning liquid from the cleaning nozzle onto the surface of the substrate W before or after the ultrasonic cleaning of the above embodiment. You can also do it. In particular, it is effective to perform the cleaning process by discharging the cleaning liquid onto the surface of the substrate W after removing particles firmly attached to the edge of the substrate W by the ultrasonic cleaning of the above embodiment. be.

Further, in the above embodiment, both the pressurizing tube 34 and the suction tube 35 were connected to the main body 31 of the ultrasonic nozzle 30, but instead of this, a suction section is provided on the side of the main body 31 to remove liquid. The droplets may be sucked through a dedicated suction path different from the ejection port 32. In this way, contaminants such as particles are not drawn into the main body 31, so that contamination within the main body 31 can be more reliably prevented.

1 Substrate processing apparatus 10 Processing chamber 20 Rotation holding unit 22 Spin chuck 25 Spin motor 30 Ultrasonic nozzle 31 Main body 32 Discharge port 33 Ultrasonic vibrator 34 Pressure tube 35 Suction tube 36 Pressure valve 37 Suction valve 40 Cup 50 Nozzle cleaning Tank 55 Drying nozzle 63 Nozzle drive section 82 Inert gas nozzle 90 Control section W Substrate

Claims (10)

A substrate processing method for performing predetermined substrate processing on a part of a processing area of a substrate, the method comprising:
a holding step for holding the substrate;
a droplet forming step of extruding a processing liquid from a discharge port of an ultrasonic nozzle to form droplets, and bringing the droplets into contact with the processing region of the substrate;
an ultrasonic wave applying step of applying ultrasonic waves to the droplet brought into contact with the processing area;
a suction step of suctioning the droplet brought into contact with the treatment area;
A substrate processing method comprising: The substrate processing method according to claim 1,
A substrate processing method, further comprising an inert gas blowing step of blowing an inert gas onto the processing area while the droplet is in contact with the substrate. The substrate processing method according to claim 2,
A substrate processing method characterized in that, in the inert gas blowing step, an inert gas is sprayed from the center of the substrate toward the outer peripheral edge. The substrate processing method according to claim 1,
A substrate processing method further comprising a nozzle cleaning step of cleaning the ultrasonic nozzle in a nozzle cleaning tank. The substrate processing method according to any one of claims 1 to 4,
A substrate processing method characterized in that the discharge port has an inner diameter of 0.5 mm or more and 1.0 mm or less. A substrate processing apparatus that performs predetermined substrate processing on a part of a processing area of a substrate,
a substrate holding part that holds the substrate;
an ultrasonic nozzle that extrudes a processing liquid from a discharge port to form droplets and applies ultrasonic waves to the droplets;
a nozzle drive mechanism that moves the ultrasonic nozzle;
Equipped with
A droplet of the processing liquid formed at the discharge port of the ultrasonic nozzle is brought into contact with the processing area of the substrate held by the substrate holder, and after applying ultrasonic waves to the droplet, the droplet is A substrate processing device characterized by suctioning. The substrate processing apparatus according to claim 6,
A substrate processing apparatus further comprising an inert gas jetting section that sprays an inert gas onto the processing area when the droplet is in contact with the substrate. The substrate processing apparatus according to claim 7,
The substrate processing apparatus is characterized in that the inert gas blowing section blows inert gas from the center of the substrate toward the outer peripheral edge. The substrate processing apparatus according to claim 6,
A substrate processing apparatus further comprising a nozzle cleaning tank for cleaning the ultrasonic nozzle. The substrate processing apparatus according to any one of claims 6 to 9,
A substrate processing apparatus characterized in that the discharge port has an inner diameter of 0.5 mm or more and 1.0 mm or less.

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