JP2000262989A - Substrate washing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably improve the washing effect of a substrate by efficiently using a small amount of washing liq. to perform highly clear washing. SOLUTION: A linear nozzle 112 is fixed so as to be located at the back surface of an arranged wafer 104. On the other hand, a linear nozzle 113 is provided in freely removable from almost central site of the wafer 104 to the outer peripheral direction, and the nozzle 113 is located in the outer peripheral direction of the wafer 104 when the nozzle 113 is not used, and the nozzle 113 is rotated to the site overlapping with the linear nozzle 112 as observed from upward at the time of washing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning apparatus, and is particularly suitably applied to cleaning of a substrate such as a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, a substrate cleaning process for manufacturing a semiconductor device has been performed by a so-called batch type cleaning method.
This cleaning method is a method in which substrates are immersed in a cleaning tank in a state where the substrates are arranged side by side in units of 10 and cleaned.

[0003]

However, in the batch-type cleaning method, the interval between the parallel substrates must be narrowed in order to improve the productivity, and as a result, the time for inflow and discharge of the cleaning liquid between the substrates is reduced. In addition, it is essentially difficult to ensure the uniformity of the cleaning liquid flow. Further, there is a disadvantage that the surface of the substrate is always affected by contamination by the back surface of the adjacent substrate.
Further, there is a problem that much time is required when the substrates are sequentially moved to the cleaning tanks of different cleaning liquids, and when the chemical solution flows into and out of the cleaning tanks. Further, there is a problem that the amount of the chemical solution and ultrapure water required for cleaning the substrate is enormous.

Accordingly, an object of the present invention is to provide a substrate cleaning apparatus capable of using a small amount of cleaning liquid extremely efficiently, performing highly clean cleaning, and significantly improving the substrate cleaning effect.

[0005]

A substrate cleaning apparatus according to the present invention is a substrate cleaning apparatus for cleaning a substrate by supplying a cleaning liquid to a substrate provided at a predetermined site, wherein the front and back surfaces of the substrate are cleaned. A pair of cleaning liquid ejecting means for simultaneously discharging the cleaning liquid, one of the cleaning liquid ejecting means has a function of applying high frequency or ultrasonic waves to the substrate via the cleaning liquid, and the other of the cleaning liquid ejecting means , Which is movable from the substantially central portion of the installed substrate to the outer peripheral direction, and operates during cleaning so that discharge areas of the cleaning liquid from both the cleaning liquid ejecting means on the substrate overlap when viewed from above. .

One embodiment of the substrate cleaning apparatus according to the present invention is a single-substrate spin cleaning apparatus which mounts each substrate and supplies the cleaning liquid while rotating the substrate in a circumferential direction.

In one embodiment of the substrate cleaning apparatus according to the present invention, the thickness of the liquid film of the cleaning liquid on the substrate is maintained at a substantially constant value equal to or more than １ ／ of the wavelength of the ultrasonic wave.

In one embodiment of the apparatus for cleaning a substrate according to the present invention, each of the cleaning liquid spraying means has a linear nozzle mounted on one side and a linear nozzle which can be fixed stationary so as to overlap with the linear nozzle when viewed from above. And a portion of the substrate on which the high-frequency or ultrasonic energy applied from one side has been propagated can be covered with the cleaning liquid by the other cleaning liquid spraying means.

In one embodiment of the substrate cleaning apparatus according to the present invention, the one cleaning liquid ejecting means is provided at a predetermined distance from the back surface of the substrate, and the other cleaning liquid ejecting means is disposed at a predetermined distance from the front surface of the substrate. It is set apart.

In one embodiment of the substrate cleaning apparatus of the present invention, the one cleaning liquid jetting means having a function of applying high frequency or ultrasonic waves to the substrate is provided below the substrate.

In one embodiment of the substrate cleaning apparatus according to the present invention, the one cleaning liquid ejecting means includes a means for generating the high frequency or ultrasonic wave and a line for transmitting the high frequency or ultrasonic wave and discharging the cleaning liquid. And the linear nozzle is formed such that the width of the linear nozzle becomes narrower upward from the means for generating high frequency or ultrasonic waves.

In one embodiment of the substrate cleaning apparatus according to the present invention, the narrowed area is within a range of a short-range sound field area from the means for generating the high frequency or ultrasonic waves.

In one embodiment of the substrate cleaning apparatus of the present invention, a plurality of step surfaces are formed on the inner wall surface of the linear nozzle in the narrowed region.

In one embodiment of the substrate cleaning apparatus according to the present invention, the concave amount of the step surface is set to approximately １ ／ of the wavelength of the high frequency or ultrasonic wave.

In one embodiment of the substrate cleaning apparatus of the present invention, a discharge port for discharging the linear liquid is provided near an upper end of the linear nozzle.

In one embodiment of the substrate cleaning apparatus according to the present invention, a liquid contacting part of each of the cleaning liquid ejecting means is made of amorphous carbon.

In one embodiment of the substrate cleaning apparatus according to the present invention, the one cleaning liquid jetting means includes a means for generating the high frequency or ultrasonic wave and a linear means for transmitting the high frequency or ultrasonic wave and discharging the cleaning liquid. A pure water is supplied to a predetermined region between the substrate having the nozzle and the means for generating high frequency or ultrasonic waves and the substrate, and the high frequency or ultrasonic waves are applied to the cleaning liquid via the pure water.

In one embodiment of the apparatus for cleaning a substrate according to the present invention, the area to which the pure water is supplied is within a range of a short-range sound field area from the means for generating high frequency or ultrasonic waves.

[0019]

In the substrate cleaning apparatus of the present invention, high-frequency or ultrasonic waves are applied to one surface (for example, the back surface) of the substrate together with the injection of the cleaning liquid from one (for example, the lower) cleaning liquid jetting means, and the other is made movable (for example). For example, the cleaning liquid is injected from a cleaning liquid injection unit (upper part) at a portion overlapping one cleaning liquid injection unit when viewed from above. In this case, since the other cleaning liquid ejecting means is located at a position opposed to the one cleaning liquid ejecting means via the substrate, the thickness of the liquid film of the cleaning liquid determined by the interval between each cleaning liquid ejecting means and the substrate is maintained at a desired constant value. Not only to sag,
High frequency or ultrasonic waves from one cleaning liquid ejecting means are applied very efficiently to the liquid film of the cleaning liquid on the other cleaning liquid ejecting means side via the substrate. Therefore, it is possible to clean the front and back surfaces of the substrate with a minimum amount of cleaning liquid with high precision.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the substrate cleaning apparatus of the present invention will be described in detail with reference to the drawings. The substrate cleaning apparatus of the present embodiment is a single wafer spin cleaning apparatus capable of realizing a wide range of functions in a wet cleaning process of a semiconductor wafer or the like.

FIG. 1 is a schematic sectional view showing a main structure of a substrate cleaning apparatus according to the present embodiment. The substrate cleaning apparatus includes a substrate (wafer) 10 such as a silicon substrate to be cleaned.
4 is a closed space for accommodating the wafer 104, and a cleaning chamber 1 provided with a gate valve 105 serving as a loading / unloading portion of the wafer 104.
01, a wafer mounting means 106 having a wafer holding pin 103 for holding the wafer 104 from the side and a rotation driving motor for rotating the fixed wafer 104 in the direction of the arrow in the figure. A cleaning liquid collision buffer plate 102 provided to surround from the side, and a cleaning liquid supply mechanism 111 for supplying a cleaning liquid to the wafer 104
It is comprised including. Here, the cleaning liquid collision buffer plate 102 is not always necessary, and the role of the cleaning liquid collision buffer plate 102 can be replaced by providing the cleaning chamber with a slightly curved surface.

The substrate cleaning apparatus is provided with a nozzle (not shown) for supplying N ₂ gas, an inert gas, or the like. When the wafer 104 is dried after cleaning, The wafer 104 is dried by rotating at a high speed while simultaneously spraying N ₂ gas or the like on the front and back surfaces, or the wafer 104 is washed while the inside of the washing chamber 101 is replaced with a high concentration of N ₂ gas or an inert gas. And so on.

The cleaning liquid supply mechanism 111 includes a pipe 107 serving as a flow path for the cleaning liquid, a cleaning liquid injection device 108 for injecting a predetermined amount of a cleaning liquid raw material or gas into the flow path to obtain a cleaning liquid having a predetermined concentration. A pair of cleaning liquid jetting means provided in the vicinity of the front surface and the rear surface of the installed wafer 104 and simultaneously supplying cleaning liquid adjusted to a desired concentration by the cleaning liquid injector 108 to the front and rear surfaces of the rotating wafer 104. It is provided with linear nozzles 112 and 113.

As shown in FIGS. 2 and 3, the linear nozzle 112 is fixed so as to be located on the back surface of the wafer 104 on which the nozzle 104 is placed. On the other hand, the linear nozzle 113 is movable from the substantially central portion of the wafer 104 to the outer peripheral direction, and when not in use, as shown in FIG.
4, and rotates to a position overlapping the linear nozzle 112 when viewed from above, as shown in FIG.

As the cleaning liquid, ultrapure water containing oxygen,
Ozone-containing ultrapure water, dilute hydrogen peroxide solution, hydrofluoric acid, hydrogen-containing hydrofluoric acid, surfactants, various chemical liquids using ultrapure water, etc. The supply is switched for each cleaning step.

Next, the configuration of the linear nozzles 112 and 113,
And the positional relationship between them will be described in detail.

FIG. 7 is a perspective view showing an example of the linear nozzle 112. The linear nozzle 112 and the linear nozzle 113 have a shape extending in the longitudinal direction as described above. In the embodiment illustrated in FIG. 7, the linear liquid discharged linearly from between the nozzles 121 and the surface of the wafer 104 and Supplied on the back.

FIGS. 4, 5 and 6 show a state in which the linear nozzles 112 and 113 are arranged on the front and back surfaces of the wafer 104 during cleaning. In these figures, the cleaning liquid 120 is supplied from both the linear nozzles 112 and 113, and megasonic (ultrasonic) is supplied to the cleaning liquid 120 from the cleaning nozzle 112 installed on the back surface (downward) of the wafer 104. Supplied. In these figures, the linear nozzles 112 and 113 extend in a direction perpendicular to the paper surface. The arrow A indicates the rotation direction of the wafer 104.

FIG. 4 shows the linear nozzles 112 and 11.
The nozzle shape of No. 3 is constituted by parallel opposed wall surfaces as shown in FIG.

The linear nozzles 112 and 11 having the structure shown in FIG.
3, the opening ends of the nozzles 112 and 113 and the wafer 104
It is possible to improve the cleaning efficiency by making the distance closer. That is, by bringing the opening ends close to each other, the resistance of the cleaning liquid 120 to the rotation of the wafer 104 due to the viscosity can be increased. Here, since the relative positions of the linear nozzle 112 and the linear nozzle 113 are set to overlap each other when viewed from above, the wafer 104 is
Of the wafer 104 can be propagated to the cleaning liquid 120 discharged from the linear nozzle 113 via the wafer 104, and the front and back surfaces of the wafer 104 can be efficiently cleaned.

FIG. 4B shows a linear nozzle 11 suitable for a case where the number of revolutions of the wafer 104 is set relatively high.
2 shows a positional relationship between 2 and 113. As described above, the positional relationship between the linear nozzle 112 and the linear nozzle 113 is shifted by a predetermined amount in accordance with the number of rotations of the wafer 104, so that the cleaning liquid 1 discharged from the linear nozzle
The position where 20 is supplied on the wafer 104 can be opposed. Therefore, the linear nozzles 112 and 113
Is desirably arranged so that the supply position of the cleaning liquid 120 on the wafer 104 overlaps on the front surface and the back surface. In this case, the linear nozzles 112 and
It is not always necessary that the position of 113 overlaps the front surface and the back surface of the wafer 104.

FIG. 5 shows another embodiment of the linear nozzle 113 installed on the surface (above) of the wafer 104. Here, the linear nozzle 113 is formed in a slope shape, and the linear liquid flows on the slope to be supplied onto the wafer 104. Then, the rotation direction of the wafer 104 indicated by the arrow A,
The directions of the linear liquids flowing on the slope are set in opposite directions.

In such a configuration, by making the direction of the linear liquid flowing on the slope opposite to the rotation direction of the wafer 104, it is possible to further improve the cleaning efficiency. That is, the energy of the cleaning liquid 120 flowing down the slope can be added to the rotation of the wafer 104. Also in this case, the linear nozzle 1
By making the distance (d ₁ ) between the wafer 13 and the wafer 104 close to each other, the cleaning efficiency can be improved by utilizing the viscosity of the cleaning liquid 120.

Here, the cleaning nozzle 112 installed on the back surface of the wafer 104 is desirably installed facing the position of the slope end, that is, the position where the cleaning liquid 120 of the cleaning nozzle 113 is supplied onto the wafer 104. Thereby, the megasonic supplied from the cleaning nozzle 112 is supplied to the wafer 104 via the cleaning liquid 120 from the cleaning nozzle 112, and further efficiently propagated to the cleaning liquid 120 supplied onto the wafer 104 from the cleaning nozzle 113. be able to.

FIG. 6 shows still another embodiment of the linear nozzle 113 installed on the surface (above) of the wafer 104.
Here, the linear nozzle 113 has a pipe shape, and the cleaning liquid 120 is supplied inside. Pipe-shaped linear nozzle 11
3 has an opening toward the surface of the wafer 104, from which the cleaning liquid 120 is supplied toward the surface of the wafer 104. Also in this case, the direction in which the cleaning liquid 120 is supplied from the pipe-shaped linear nozzle
Since the rotation direction is opposite to the rotation direction of 04, an effect equivalent to that of the linear nozzle 113 in the mode shown in FIG. 5 can be obtained. Further, by adjusting the distance (d ₂ ) between the lower end of the pipe-shaped linear nozzle 113 and the wafer 104, it is possible to improve the cleaning efficiency by utilizing the viscosity of the cleaning liquid 120. The opening for supplying the cleaning liquid from the pipe-shaped linear nozzle 113 toward the wafer 104 may be a linear slit or a plurality of openings (holes).

Next, the configuration of the linear nozzles 112 and 113 will be described in detail. In the following description, the linear nozzle 112 installed below the wafer 104 will be mainly described, but it is of course possible to apply the configuration of the linear nozzle 113 without the megasonic supply mechanism. is there.

FIG. 7 is a perspective view showing the entire structure of the linear nozzle 112. As shown in FIG. The linear nozzle 112 includes a nozzle 121,
Ultrasonic vibrator 123, diaphragm 122, cleaning liquid supply pipe 12
4. Here, in FIG. 7, for convenience, the end face of the nozzle 121 is shown as a cross section.
Actually, the nozzle 121 is also formed on the end face, and the linear liquid supplied from the linear liquid supply pipe 124 is supplied only upward.

The nozzle 1 which is a liquid contact part of the cleaning liquid spraying means
21 and the diaphragm 122 are formed of amorphous carbon. This makes it possible to minimize the generation of particles due to the cleaning liquid, especially the hydrofluoric acid solution.

The ultrasonic vibrator 123 is composed of, for example, a piezoelectric element made of ceramic, and generates ultrasonic vibration by applying a predetermined high frequency. The ultrasonic vibration is further propagated upward through the vibration plate 122 attached on the ultrasonic vibrator 123.

The cleaning liquid supply pipe 124 supplies the cleaning liquid 120 onto the vibrator 122. Ultrasonic vibration (megasonic) from the diaphragm 122 is propagated to the cleaning liquid 120 supplied on the vibrator 122.

FIG. 8 is a cross-sectional view schematically showing the wavefront transmitted from the oscillator 122 to the cleaning liquid 120 by megasonic. From the ultrasonic oscillator 123 to the oscillator 1
The vibration propagating into the cleaning liquid 120 via the nozzle 22 propagates as a spherical wave generated from each point of the vibration plate 122 on the ultrasonic vibrator 123, propagates as an overlapping plane wave in the arrow B direction, and It is conveyed to the back of.

The range of the distance E upward from the diaphragm 122 shown in FIG. 8 indicates a short-range (close) sound field area. In this region, a spherical wave is radially propagated in the cleaning liquid because it is close to the vibration source (for example, in the direction of arrow A). Therefore, in this range, the vibration propagating in the horizontal direction is reflected by the nozzle 121, and an unnecessary reflected wave may be transmitted into the cleaning liquid 120.

In this embodiment, in consideration of this state, the slope 121a is formed by widening the wall surface of the nozzle 121 toward the lower surface in the short-range sound field region.
In this way, by forming the nozzle 121 as the inclined surface 121a in the short-range sound field region and enlarging the width, it is possible to minimize the generation of unnecessary reflected waves due to the megasonic reflecting on the inner wall surface of the nozzle 121. Can be.

The short-range sound field area E is defined by the following equation when the wavelength of the megasonic is λ and the width of the ultrasonic vibrator is 2d. E = d ² / λ

Therefore, it is desirable that the vertical distance of the slope 121a is set to be larger than the short-range sound field area (E = d ² / λ). In other words, when the megasonic frequency is 1.5 MHz, the wavelength (λ) is 1 mm, and the width (2d) of the ultrasonic vibrator 123 is 3 mm, the short-range sound field region is 2d = 3. Then, E = 1.5 ² /1=2.25 (mm), so that the vertical distance of the slope 121a is 2.25 (mm).
By setting the diameter to be equal to or more than mm, it is possible to obtain a nozzle shape in which adverse effects due to reflected waves are suppressed.

Also, the megasonic frequency is set to 1.5 MHz.
z, the wavelength (λ) is 1 mm, and the width (2
In the case where the d) and 5 mm, the near field region, E = 2.25 ² /1=6.25(mm). Therefore, the vertical distance of the slope 121a 6.25
By setting the diameter to be equal to or more than mm, it is possible to obtain a nozzle shape in which adverse effects due to reflected waves are suppressed.

FIG. 11 is a perspective view showing a state where the inclined surface 121a of the nozzle 121 is viewed from the inside. Minute steps 121c (gratings) are formed at predetermined intervals on the inner wall surface of the slope 121a. FIG. 12 shows the slope 121a.
Shows a cross section in a direction perpendicular to the direction in which

As shown in FIG. 12, the concave amount of the step 121c is preferably set to about １ ／ of the megasonic wavelength (λ). By setting the concave amount in this way,
When megasonic is reflected on the inner wall surface of the slope 121a, it is possible to effectively interfere the wave traveling from the diaphragm 122 toward the slope 121a with the reflected wave on the inner wall surface 121c, and attenuate the reflected wave accurately. Is possible.

Next, referring to FIG.
The flow of the cleaning liquid 120 in the inside will be described. As described above, above the short-range sound field region E, the megasonic propagates upward in the cleaning liquid 120 as a plane wave. Therefore, the cleaning liquid 120 flows upward with the width of the plane wave shown in FIG.

Here, as shown in FIG. 8, the horizontal width of the plane wave is substantially the same as the horizontal width (D ₁ ) of the ultrasonic transducer 123. Therefore, the cleaning liquid 120 flows upward in this range, and the surface of the nozzle 121 rises at the center of the interval (D ₂ ) between the nozzles 121.

In this embodiment, the nozzle 1
The interval (D ₂ ) of 21 is the width (D ₁ ) of the ultrasonic transducer 123.
It is set larger than. As an example, when the width (D ₁ ) of the ultrasonic transducer 123 is about 3 mm, the interval (D ₂ ) between the nozzles 121 is set to about 5 mm. When the width (D ₁ ) of the ultrasonic vibrator 123 is about 5 mm, it is preferable to set the interval (D ₂ ) between the nozzles 121 to about 8 mm.

As described above, the interval (D ₂ ) between the nozzles 121
Is set to be larger than the width (D ₁ ) of the ultrasonic vibrator 123, so that the cleaning liquid 120 that has flowed upward flows laterally on the surface, and as shown by arrows in FIG.
Will flow down along the vertical wall of the.

As described above, the cleaning liquid 120 directed upwards
By flowing downward along the wall surface of the nozzle 121 and circulating it, the amount of the cleaning liquid 120 flowing out from the nozzle 121 to the outside can be minimized, and the megasonic from the ultrasonic vibrator 123 can be reliably prevented. It can propagate to the wafer 104.

Next, the state of the cleaning liquid 120 in the linear nozzle 112 when the wafer 104 is dried will be described. FIG. 10 shows the linear nozzle 112 during drying.

As shown in FIG. 10, a discharge port 121b is provided on a wall surface of the nozzle 121 of the linear nozzle 112. During drying, the supply of the cleaning liquid 120 from the cleaning liquid supply pipe 124 is stopped, and the wafer 1
The wafer 104 is dried at a high speed while simultaneously blowing N ₂ gas or the like on the front and back surfaces of the wafer 04.

At this time, when the supply of the cleaning liquid 120 from the cleaning liquid supply pipe 124 is stopped, the cleaning liquid 120 in the nozzle 121 is discharged from the discharge port 121b. Thus, the liquid level of the cleaning liquid 120 in the nozzle 121 is located below the outlet 121b. Therefore, the surface of the cleaning liquid 120 can be sufficiently separated from the tip of the nozzle 121. This allows the wafer 104 to be dried during drying.
Even if is rotated at a high speed, a sufficient distance is secured from the back surface of the wafer 104 to the front surface of the cleaning liquid 120, so that the cleaning liquid 120 can be prevented from blowing up and being separated by the high-speed rotation, and can be transferred to the wafer 104 during drying. Cleaning liquid 1
20 can be prevented from adhering. In particular, when the interval (D ₂ ) between the nozzles 121 is larger than 2 mm, the suction of the cleaning liquid 1120 upward is intense.
By providing the outlet 121b, this suction can be suppressed. It should be noted that one or several outlets 121b can be provided.

Next, a more specific configuration of the linear nozzle 11 will be described.
2 will be described with reference to FIGS.

FIG. 13 is a perspective view showing the entire structure of the linear nozzle 112. As shown in FIG. Here, the cleaning liquid 120 is discharged to the back surface of the wafer 104 from the slit 125a. A cleaning liquid supply pipe 128 supplies the cleaning liquid 120 onto the diaphragm. Reference numeral 126 denotes a vibrator cover, in which an ultrasonic vibrator 131 is stored. Reference numeral 127 denotes a power supply cable for transmitting a high frequency to the ultrasonic transducer 131.

FIG. 14 is a diagram showing a cross section of the linear nozzle 112 in a direction perpendicular to the direction in which the slit 125a extends. The linear nozzle 112 includes an upper block (horn part) 125, a diaphragm 130, a lower block 132, and a vibrator cover 126 as main constituent members.

The upper block 125 is a member corresponding to the nozzle 121 of the linear nozzle 112 described with reference to FIG.
Are formed wider toward the diaphragm 130. The wide portion corresponds to the above-described short-range sound field region.

The diaphragm 130 is provided on the lower surface of the upper block 125.
Is attached. Upper block 125 and diaphragm 13
Numeral 0 is in close contact with the peripheral portion, and the O-ring 129 prevents the cleaning liquid 120 from leaking. Then, the cleaning liquid 120 is supplied between the upper block 125 and the vibration plate 130 from the cleaning liquid supply pipe 128. Therefore, the cleaning liquid 120 is provided between the upper block 125 and the diaphragm 130.
And it exists inside the O-ring 129.

The ultrasonic vibrator 13 is provided on the back surface of the vibrating plate 130.
1 is pasted. The portion of the lower block 132 corresponding to the ultrasonic transducer 131 is an opening, and the ultrasonic transducer 131 is accommodated in this opening.

A transducer cover 126 is attached to the lower part of the lower block 132 so as to cover the ultrasonic transducer 131. Preferably, N ₂ gas or the like is caused to flow in the space inside the vibrator cover 126 so that the vibrator cover 1
It is possible to minimize the contamination that occurs in 26.

The cleaning liquid supply pipe 128 is connected to the lower block 132
And, it is supplied between the upper block 125 and the diaphragm 130 through the diaphragm 130. Here, the cleaning liquid supply pipe 12
8 is connected to a supply groove 125c formed in the upper block 125.

FIG. 15 is a plan view of the upper block 125 as viewed from below. The supply groove 125c is formed in a U shape so as to surround the slit 125a. And FIG.
Reference numeral 125g shown in FIG. 5 indicates a portion to which the cleaning liquid supply pipe 128 is connected in the supply groove 125c.

A gap is formed between the supply groove 125c and the slope 125b of the slit 125a. Upper block 1
The surface 125d forming the gap in 25 is formed as a concave surface at a smaller amount than the portion closely contacting the diaphragm 130 at the periphery of the upper block 125, and the diaphragm 13
When they are brought into close contact with 0, a minute gap is formed. An appropriate amount of the gap is about 0.2 mm.

FIG. 16 is a schematic diagram showing a state in which the cleaning liquid 120 supplied from the cleaning liquid supply pipe 128 to the supply groove 125c reaches the slit 125a through the gap. FIG. 16 is a plan view of the upper block 125 as viewed from below similarly to FIG. 15, but shows a plan view of an enlarged state of a region indicated by a two-dot chain line 125f shown in FIG.

As shown in FIG. 16, the cleaning liquid supply pipe 128
The cleaning liquid 120 supplied to the supply groove 125c from below flows along the supply groove 125c, and goes directly below the slit 125a through a gap formed by the surface 125d. Immediately below the slit 125a, since the vibration plate 130 is vibrated by the ultrasonic vibrator 130, the cleaning liquid 120 flows upward as described with reference to FIGS.

In the apparatus shown in FIGS. 13 to 16 described above, the diaphragm 13 just below the slit 125a
Since the cleaning liquid 120 can be uniformly supplied to 0,
The cleaning liquid 120 to be supplied to the back surface of the wafer 104 can be supplied uniformly and without unevenness.

As described above, the linear nozzles 112 and 113 are disposed on the front and back surfaces of the wafer 104, respectively.
By supplying megasonic from the linear nozzle 112 below the wafer 104, the cleaning liquid 1 is supplied by megasonic.
Bubbles generated in the wafer 20 are transferred from the linear nozzle 112 to the wafer 10.
4 can be effectively removed from the cleaning liquid 120 supplied to the back surface. In other words, when the ultrasonic transducer is installed on the linear nozzle 113 installed above the wafer 104, when bubbles are generated in the linear nozzle 113, the air bubbles are lifted upward and left behind just below the diaphragm. It is assumed that the megasonic does not efficiently propagate to the cleaning liquid 120. By installing the ultrasonic oscillators 123 and 130 in the linear nozzle 112 installed above the wafer 104 as in the present embodiment, bubbles in the cleaning liquid 120 are removed from the contact surface between the cleaning liquid 120 and the wafer 104 or the side thereof. It is possible to surely escape from the direction.

Hereinafter, a wafer cleaning process using the single wafer spin cleaning apparatus shown in FIGS. 1 to 3 will be described in the order of steps with reference to FIG. First, the ultrapure water containing ozone (O ₃ ) is supplied from the linear nozzles 112 and 113 to the rotating wafer 10.
4 is supplied to the front and back surfaces (step S1). This allows
Organic substances, metals, various particles and the like adsorbed on the front and back surfaces of the wafer 104 are removed.

Subsequently, a mixed solution of hydrofluoric acid (HF) mixed with a hydrogen peroxide solution (H ₂ O ₂ ) and a surfactant was used, and the frequency of the mixed solution was 0.8 MHz to 6.0.
The cleaning liquid irradiated with megasonics of MHz is supplied to the front and back surfaces of the wafer 104 in the same manner (step S2). Specifically, the mixed solution is sprayed from the linear nozzle 112 onto the wafer 104 and megasonic is applied. At the same time, the linear nozzle 1
The mixed solution is injected from 13. At this time, not only the thickness of the liquid film is maintained at a desired constant value, but also the linear nozzle 112
Is very efficiently applied to the liquid film of the mixed solution of the linear nozzle 113 via the wafer 104. The thickness of the liquid film is desirably about １ ／ or more of the megasonic wavelength of the mixed solution. 1
Below about / 4, it is difficult to sufficiently superpose the megasonic on the mixed solution injected from the linear nozzles 112 and 113. The megasonic wavelength is about 1.5 mm when the frequency is 1 MHz, about 1.0 mm at 1.5 MHz, and about 0.3 mm at 5 MHz.

As a result, in step S1, the wafer 104
Organic substances, metals, various particles, etc., remaining in the substrate are removed. Here, the frequency of the megasonic irradiating the cleaning liquid is 0.8 M
When the frequency is lower than Hz, a sufficient cleaning effect cannot be expected. On the other hand, when the frequency is too high, there is a concern that a predetermined portion or the like of the cleaning apparatus may have some adverse effect. Therefore, it is considered that the upper limit is about 6.0 MHz at present. However, if the concern of the adverse effect is eliminated or it is possible to eliminate it, it is expected that a higher frequency will be used in the future.

Subsequently, a cleaning liquid which is ultrapure water containing ozone is supplied to the front and back surfaces of the wafer 104 in the same manner (Step S3). Thus, the surfactant remaining on the wafer 104 in step S2 is removed.

Subsequently, ultrapure water is similarly applied to the wafer 104.
(Step S4). Thus, the surface of the wafer 104 is rinsed. Thereafter, the wafer 104 is dried by passing N ₂ gas through (Step S5).
The cleaning process ends.

As described above, according to the present embodiment, since the linear nozzles 113 are located at positions opposed to the linear nozzles 112 via the wafer 104 during cleaning, each linear nozzle 11
Not only is the thickness of the cleaning liquid film determined by the distance between the wafers 2 and 113 and the wafer 104 kept at a desired constant value, but also the megasonics from the cleaning nozzle 112 cause the cleaning liquid of the linear nozzle 113 to pass through the wafer 104. It will be applied very efficiently to the liquid film. Therefore, it is possible to clean the front and back surfaces of the wafer 104 with a minimum amount of cleaning liquid with high precision.

(Experimental Example) Here, an experiment was conducted to examine the relationship between the thickness of the liquid film of the cleaning liquid obtained by the above cleaning process and the cleanliness of the wafer surface. Hereinafter, this experiment will be described.

The cleaning process was performed under the following conditions, and the relationship between the liquid film thickness (mm) and the particle removal rate (%) was examined. Here, ultrapure water was used as the cleaning liquid, the megasonic frequency was 1.5 MHz (applied only from the back surface of the wafer), and the cleaning time was 16 seconds.
The experimental results are shown in Table 1 below.

[0079]

[Table 1]

The wafers had a diameter of 8 inches, and the particles having a diameter of 0.16 μm or more were counted. The particle removal rate (%) is 100 ×
{1- (number of particles on wafer after cleaning / number of particles on wafer before cleaning)}.

As is evident from Table 1, according to the substrate cleaning apparatus of the present embodiment, it is possible to achieve a great improvement in the cleanliness of the wafer by keeping the thickness of the cleaning liquid film at a desired value. Was.

Next, referring to FIG.
Another mode of the cleaning nozzle 112 installed in the lower part of 4 will be described. The cleaning nozzle 112 shown in FIG. 18 includes a nozzle 121, an ultrasonic vibrator 123, a vibration plate 122, and a cleaning liquid supply pipe 124. In this aspect,
Unlike the configuration shown in FIG. 7, the nozzle 121 arranged at a predetermined interval above the diaphragm 122 is different from the amorphous carbon plate 14 installed horizontally at the bottom.
Connected by 0. As described above, the nozzle 121 is made of amorphous carbon. Further, the thickness of the amorphous carbon plate 140 is about 0.5 mm or １ ／ of the megasonic wavelength from the vibrator 123.
It is desirable to be about. Although the diaphragm 122 uses amorphous carbon in the above-described example, quartz may be used.

Then, the vibration plate 122 and the carbon plate 140
Between them, pure water (UPW) is supplied. Pure water is
The water is supplied from the pure water supply pipe 141 and discharged from the pure water discharge pipe 142. The vibration transmitted from the vibrator 123 to the vibration plate 122 propagates to the carbon plate 140 via pure water. The cleaning liquid 12 supplied on the carbon plate 140
The vibration propagates to zero.

As described above, the range of the distance E (= d ² / λ) upward from the diaphragm 122 is a short-range sound field area. Therefore, by ensuring that the distance between the diaphragm 122 and the carbon plate 140 is larger than the distance E, a plane wave can be propagated from above the carbon plate 140 toward the wafer 104. In addition, the distance from the horizontal end face of the diaphragm 122 to the pure water supply pipe 141 and the pure water discharge pipe 142 is also kept at the distance E or more. As a result, transmission of unnecessary reflected waves in pure water can be suppressed.

In the cleaning nozzle 112 having such a configuration, by supplying pure water mainly to the short-range sound field region, transmission of unnecessary reflected waves into the cleaning liquid 120 can be suppressed, so that the wafer can be efficiently processed. 104 can be cleaned. Also, the oscillator 123 and the wafer 104
Is required to be longer than the distance E.
By supplying pure water between the wafer 23 and the wafer 104, it is not necessary to arrange a member made of amorphous carbon or the like having a relatively high material cost in this region. Therefore, the manufacturing cost of the cleaning nozzle 112 can be significantly reduced.

[0086]

According to the present invention, it is possible to use a small amount of a cleaning liquid extremely efficiently and to perform highly clean cleaning, thereby greatly improving the substrate cleaning effect.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main configuration of a substrate cleaning apparatus (single wafer spin cleaning apparatus) according to an embodiment of the present invention.

FIG. 2 is an enlarged schematic view showing the vicinity of a cleaning nozzle of the substrate cleaning apparatus when not in use.

FIG. 3 is an enlarged schematic view showing the vicinity of a cleaning nozzle of the substrate cleaning apparatus in use.

FIG. 4 is a schematic view showing a linear nozzle of the substrate cleaning apparatus according to one embodiment of the present invention.

FIG. 5 is a schematic view showing a linear nozzle of the substrate cleaning apparatus according to one embodiment of the present invention.

FIG. 6 is a schematic view showing a linear nozzle of the substrate cleaning apparatus according to one embodiment of the present invention.

FIG. 7 is a schematic diagram showing a linear nozzle provided on a lower surface of a wafer of the substrate cleaning apparatus according to one embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a wave propagating in a cleaning liquid in a linear nozzle according to an embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a flow in a cleaning liquid in a linear nozzle according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a state of a cleaning liquid during drying in a linear nozzle according to an embodiment of the present invention.

FIG. 11 is a perspective view showing an inner wall surface of a linear nozzle according to an embodiment of the present invention.

FIG. 12 is a sectional view showing an inner wall surface of a linear nozzle according to an embodiment of the present invention.

FIG. 13 is a perspective view showing a specific configuration of a linear nozzle according to an embodiment of the present invention.

FIG. 14 is a sectional view showing a specific configuration of a linear nozzle according to an embodiment of the present invention.

FIG. 15 is a plan view showing an upper block of a linear nozzle according to an embodiment of the present invention.

FIG. 16 is an enlarged plan view showing an upper block of a linear nozzle according to an embodiment of the present invention.

FIG. 17 is a block diagram illustrating a cleaning process using the substrate cleaning apparatus according to the embodiment of the present invention.

FIG. 18 is a schematic view showing another aspect of the linear nozzle provided on the lower surface of the wafer of the substrate cleaning apparatus according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 Cleaning chamber 102 Cleaning liquid collision buffer plate 103 Wafer holding pin 104 Wafer 105 Gate valve 106 Wafer setting means 107 Piping 108 Cleaning raw liquid injector 111 Cleaning liquid supply mechanism 112, 113 Linear nozzle 120 Cleaning liquid 121 Nozzle 122 Vibration plate 123 Ultrasonic vibrator 123 124 Cleaning liquid supply pipe 125 Upper block 126 Vibrator cover 127 Power supply cable 128 Cleaning liquid supply pipe 129, 134 O-ring 130 Vibration plate 131 Ultrasonic vibrator 132 Lower block 140 Amorphous carbon plate 141 Pure water supply pipe 142 Pure water discharge pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuhisa Nitta 4-1-1 Hongo, Bunkyo-ku, Tokyo Inside the Ultra Clean Technology Development Laboratory (72) Inventor Masahiro Miki 4-1-1 Hongo, Bunkyo-ku, Tokyo No.4 Inside Ultra Clean Technology Development Research Center

Claims (14)

[Claims] 1. A substrate cleaning apparatus for cleaning a substrate by supplying a cleaning liquid to a substrate provided at a predetermined site, wherein the cleaning liquid is discharged to a front surface and a back surface of the substrate at the same time. The cleaning liquid ejecting means has a function of applying a high frequency or an ultrasonic wave to the substrate via the cleaning liquid, and the other cleaning liquid ejecting means has an outer periphery from a substantially central portion of the installed substrate. A substrate cleaning apparatus, wherein the substrate cleaning apparatus is movable in two directions, and operates so that discharge areas of the cleaning liquid from both of the cleaning liquid ejecting means on the substrate overlap when viewed from above. 2. The substrate cleaning apparatus according to claim 1, wherein the substrate cleaning apparatus is a single-substrate spin cleaning apparatus which is mounted on each substrate and supplies the cleaning liquid while rotating the substrate in a circumferential direction. 3. The substrate cleaning apparatus according to claim 1, wherein the thickness of the liquid film of the cleaning liquid on the substrate is maintained at a substantially constant value equal to or more than １ ／ of the wavelength of the ultrasonic wave. 4. The cleaning liquid jetting means has a linear nozzle installed on one side, and a linear nozzle which can be fixed stationary so as to overlap with the linear nozzle installed on one side so as to overlap with the linear nozzle when viewed from above. The portion on the substrate to which the high-frequency or ultrasonic energy has been propagated can be covered with the cleaning liquid by the other cleaning liquid ejecting means.
4. The substrate cleaning apparatus according to any one of 3. 5. The method according to claim 1, wherein the one cleaning liquid ejecting means is installed at a predetermined distance from the back surface of the substrate, and the other cleaning liquid ejecting means is installed at a predetermined distance from the surface of the substrate. The substrate cleaning apparatus according to claim 1. 6. The cleaning liquid jetting means having a function of applying high frequency or ultrasonic waves to the substrate is provided at a lower portion of the substrate. A substrate cleaning apparatus as described in the above. 7. The one cleaning liquid ejecting means includes: a means for generating the high frequency or ultrasonic wave; and a linear nozzle through which the high frequency or ultrasonic wave is propagated to discharge the cleaning liquid. 7. The substrate cleaning apparatus according to claim 6, wherein the width of the substrate is narrowed upward from the means for generating high frequency or ultrasonic waves. 8. The substrate cleaning apparatus according to claim 7, wherein the narrowed area is set within a range of a short-range sound field area from the high-frequency or ultrasonic wave generating means. . 9. The substrate cleaning apparatus according to claim 8, wherein a plurality of step surfaces are formed on an inner wall surface of the linear nozzle in the narrowed region. 10. The substrate cleaning apparatus according to claim 9, wherein a concave amount of the step surface is set to approximately １ ／ of a wavelength of the high frequency or ultrasonic wave. 11. The substrate linear device according to claim 6, wherein a discharge port for discharging the linear liquid is provided near an upper end of the linear nozzle. . 12. The cleaning liquid jetting means according to claim 6, wherein a liquid contact portion of said cleaning liquid jetting means is made of amorphous carbon.
12. The substrate linear device according to any one of items 11 to 11. 13. The one cleaning liquid ejecting means includes: a means for generating the high frequency or ultrasonic wave; and a linear nozzle through which the high frequency or ultrasonic wave is propagated and discharges the cleaning liquid. The substrate according to claim 6, wherein pure water is supplied to a predetermined region between the means for generating a sound wave and the substrate, and the high frequency or ultrasonic wave is applied to the cleaning liquid via the pure water. Cleaning equipment. 14. The substrate cleaning method according to claim 13, wherein the region to which the pure water is supplied is within a range of a short-range sound field region from the high-frequency or ultrasonic wave generating unit. apparatus.