JP2003022994A - Wafer washing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer washing method for washing a wafer on which a pattern is formed. SOLUTION: By applying the washing treatment of a wafer W on which the pattern is formed while using a two-fluid nozzle 7 for forming mist M by mixing a pressed gas and a washing liquid, particles can be removed without damaging the pattern. As one of appropriate washing conditions, a distance L from a discharge port for discharging the mist M to the wafer W is 10 mm, the quantity of gases to be used is 60 L/min, the quantity of washing liquids to be used is 150 mL/min, and the liquid drops of a particle diameter within the range from 5 μm to 20 μm are formed. As a washing liquid, ultra-pure water, to which carbon dioxide (CO2 ) is added, is used and as a gas, nitrogen (N2 ) of inert gas is used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor substrate, a glass substrate for a liquid crystal display, a glass substrate for a photomask,
The present invention relates to a substrate cleaning method in which a cleaning liquid is supplied to a substrate for an optical disk (hereinafter, simply referred to as a substrate) to perform a cleaning process, and particularly, a technique for cleaning a substrate on which a pattern such as a pattern formed by photolithography or a wiring pattern formed by vapor deposition Regarding

[0002]

2. Description of the Related Art Conventionally, as a technique for forming a pattern on a substrate, for example, photolithography in which a photoresist is applied and mask alignment is performed, and then etching is performed to form a pattern, or a wiring pattern of metal, alloy, metal compound, or the like There is vapor deposition (sputtering, CVD, etc.) for forming the.

[0003]

However, as shown in FIG. 3, the substrate W having such a convex pattern PA has the following problems. That is, if the substrate W on which the pattern PA is formed is washed in order to remove the particles Q (particles) of the minute foreign matter attached to the substrate W, the pattern PA is damaged.

As a method for cleaning the substrate, chemical cleaning such as cleaning with a chemical solution, scrub cleaning by directly contacting a brush with a substrate rotating at high speed, or supplying ultrapure water to which ultrasonic waves are applied to the substrate. Then, ultrasonic vibration is applied to the substrate to perform sonic cleaning, such as physical cleaning. However, the chemical cleaning is not effective because it causes a chemical reaction with the pattern PA to damage the pattern. In the case of physical cleaning, first, in megasonic cleaning, particles Q of 1 μm or less cannot be removed sufficiently, and ultrasonic waves are applied to the substrate W, which damages the pattern PA.
On the other hand, in the scrub cleaning, since the brush directly contacts the substrate W, the pattern PA is also damaged and is not effective. This is because the cleaning power for the convex pattern PA is not optimized by setting the cleaning power by pressing the brush at the surface position of the substrate W, and it is difficult to control. Was

The present invention has been made in view of the above circumstances, and an object thereof is to provide a substrate cleaning method for cleaning a patterned substrate.

[0006]

In order to achieve such an object, the present inventors changed the conditions such as the cleaning method, the cleaning liquid to be used and the amount of the cleaning liquid to be used to form the patterned substrate. I tried cleaning.

Among the various conditions mentioned above, under certain conditions, it was possible to remove the particles without damaging the pattern. Therefore, the inventors of the present invention have conceived that the above object can be achieved based on the conditions.

The present invention created based on the above knowledge has the following configuration. That is, the invention according to claim 1 uses a two-fluid nozzle that mixes the cleaning liquid and the pressurized gas inside the nozzle to form a mist, and discharges the formed mist from the discharge port at the tip of the nozzle. hand,
A method for cleaning a substrate, comprising: cleaning the substrate; in the two-fluid nozzle, a gas of 20 L / min inside the nozzle.
To 100 L / min to form a mist, and the mist-forming cleaning liquid is discharged onto the processed surface of the patterned substrate to perform a cleaning process on the substrate. To do.

[Operation / Effect] According to the invention described in claim 1, the mist is formed by mixing the cleaning liquid and the pressurized gas under various cleaning conditions, and the formed mist is discharged. By using the two-fluid nozzle for cleaning the patterned substrate, the particles can be removed without damaging the pattern.

More specifically, according to the two-fluid nozzle, the cleaning liquid is divided by the gas supplied to form droplets. At the same time, the gas also acts as a carrier at the time of ejecting the droplet, so that the supply amount of the gas functions as a parameter for controlling the ejection speed of the droplet, that is, the cleaning effect on the processing surface of the substrate. Therefore, by controlling the gas supply amount, a better substrate cleaning process is performed. Further, in order to prevent the damage of the pattern, it is desired that the pattern be used in a range where the cleaning power is small, but it is important that the width of the change in the cleaning power between the upper end and the lower end of the pattern is small.

Here, according to the cleaning method of the present invention, since mist droplets having individually controlled particle diameters are supplied,
The characteristic that the cleaning power does not change so much within the range of the unevenness due to the fine pattern has a favorable effect on the removal of particles. Therefore, as for the pattern of the substrate to be cleaned, a convex pattern is formed on the substrate surface (the invention according to claim 2).

The preferred amounts of gas and cleaning liquid used in the above-mentioned two-fluid nozzle are as follows. In the case of gas, the range from 20 L / min to 100 L / min,
Further, the range is from 20 L / min to 60 L / min (the invention according to claim 3). Further, in the case of a cleaning liquid, the range from 10 mL / min to 200 mL / min (the invention according to claim 4), and further 100 mL / mi
n to 200 mL / min (invention according to claim 5), further 100 mL / min to 150 mL / min
The range is up to min (the invention of claim 6). Within the above range, the particles can be suitably removed without damaging the pattern.

Further, the cleaning liquid is composed of pure water, carbon dioxide (C
It is preferable that O ₂ ) is added (the invention according to claim 7). By adding carbon dioxide, the specific resistance value decreases,
The static electricity generated by the friction between the processing surface of the substrate and the cleaning liquid is suppressed, and the dielectric breakdown of the substrate can be prevented.
Furthermore, the gas is preferably an inert gas (the invention according to claim 8). Examples of the inert gas include nitrogen (N ₂ ), dry (non-wet) air (dry air), and argon (Ar). The use of the inert gas does not cause a chemical reaction with the cleaning liquid, the substrate or the pattern, so that the cleaning liquid, the substrate or the pattern is not adversely affected.

Further, a preferable distance from the discharge port for discharging mist in the two-fluid nozzle to the processing surface of the substrate is in the range of 5 mm to 10 mm (the invention according to claim 9). Within the above range, the particles can be suitably removed while maintaining the cleaning power without damaging the pattern.

Further, the mist droplet diameter is from 5 μm to 2
The range is up to 0 μm (the invention of claim 10).
Particles between the patterns can be suitably removed without damaging the patterns within the above range.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a substrate cleaning apparatus used in a substrate cleaning method according to an embodiment, and FIG. 2 is a vertical sectional view showing a configuration of a cleaning nozzle (two-fluid nozzle) according to the embodiment. In this embodiment, a substrate on which a pattern is formed in an apparatus (not shown) for performing a photolithography process or a vapor deposition process, that is, a substrate having a convex pattern on the surface of the substrate is cleaned by the substrate cleaning according to this embodiment. Description will be given by taking as an example the case of transporting to the apparatus and further cleaning using a two-fluid nozzle.

Six support pins 1 formed in a cylindrical shape
As shown in FIG. 1, the disk-shaped spin chuck 1 on which a is erected is rotatably driven by an electric motor 5 via a rotary shaft 3 connected to the bottom surface. In FIG. 1, only two support pins 1a are shown in order to avoid making the drawing complicated. By this rotation drive, the substrate W whose peripheral portion is abutted and supported by the support pins 1a is rotated in the horizontal plane around the rotation center P. Discharge around the spin chuck 1 from a two-fluid cleaning nozzle 7 (hereinafter, abbreviated as “two-fluid nozzle 7”) that mixes a pressurized gas G and a cleaning liquid S to form a mist M. A scattering prevention cup 9 is provided to prevent the generated mist M from scattering. The scattering prevention cup 9 is configured to move up and down with respect to the spin chuck 1 when receiving the uncleaned substrate W from the spin chuck 1, as indicated by an arrow in the figure.

In the case where the substrate W is not washed, as described above, the substrate W in this embodiment is a separate device (not shown) for forming a pattern, for example, photolithography process or vapor deposition process. A substrate on which a pattern is formed is used. In addition, you may perform a washing process and a drying process also in the above-mentioned apparatus. The cleaning process in this case is 2
It is not necessary to use a fluid nozzle, and it is a physical cleaning such as a chemical cleaning for cleaning only with a cleaning liquid, a scrub cleaning for directly contacting a brush for cleaning, or a sonic cleaning for applying ultrasonic vibration. Good.

As shown in FIG. 1, the two-fluid nozzle 7 is supported by a support arm 11 in an inclined direction with its discharge port oriented perpendicular to the processing surface of the substrate W, as shown by the arrow in the figure. The drive mechanism 13 is configured to move up and down / swing together with the support arm 11. The support arm 1
1 may be configured to be swingable in parallel to the horizontal plane, and the two-fluid nozzle 7 may be configured to cross the processing surface of the substrate W. Note that the two-fluid nozzle 7 is arranged so that the ejection port of the two-fluid nozzle 7 is located at a position separated from the processing surface of the substrate W by a distance L during cleaning. This distance L is preferably in the range of 5 mm to 10 mm. Within the above range, the particles can be suitably removed without damaging the pattern. By the way, if it is less than 5 mm, it is difficult to adjust the two-fluid nozzle 7 because the two-fluid nozzle 7 and the substrate W are likely to come into contact with each other, and particles removed by cleaning the substrate W scatter to the two-fluid nozzle 7. It may adhere and further damage the pattern. On the contrary, if it exceeds 10 mm,
The cleaning effect on the substrate W may be reduced.

A supply pipe 15a for supplying the cleaning liquid S and a gas introduction pipe 15b for introducing the compressed gas G are connected to the body of the two-fluid nozzle 7. Supply pipe 15a
Is configured so that ultrapure water to which carbon dioxide (CO ₂ ) is added is supplied as a cleaning liquid S from an ultrapure water device 21 connected via a control valve 19 which is controlled to open and close by a controller 17. ing. In addition, the gas introduction pipe 15b has a control valve 2 which is opened and closed by a controller 17.
3, the gas G is supplied from a gas supply device 27 which is connected via a controller 3 and a pressure adjuster 25 which performs pressure adjustment such as pressurization and depressurization of the gas G.

In this embodiment, ultrapure water to which carbon dioxide is added is used as the cleaning liquid S, but only acid, alkali, pure water, ozone water obtained by dissolving ozone in pure water, etc. are exemplified. As described above, the cleaning liquid is not particularly limited as long as it is a cleaning liquid used for normal substrate cleaning. Further, in this embodiment, by using the ultrapure water added with carbon dioxide as the cleaning liquid S, the specific resistance value is lowered, and the static electricity generated by the friction between the processing surface of the substrate W and the cleaning liquid S is suppressed. The dielectric breakdown of the substrate W can be prevented.

As a gas used as the gas G,
In the embodiment, nitrogen (N ₂) Is used.
As an inert gas, for example, in a dry state, not wet
There are air (dry air), argon (Ar), and the like.
In this embodiment, the cleaning liquid S and the base are prepared by using an inert gas.
Since it does not chemically react with the plate W or pattern, it can be washed.
It does not adversely affect the cleaning solution S, the substrate W, or the pattern.
Yes.

The electric motor 5, the drive mechanism 13, the control valves 19 and 23, and the ultrapure water supply device 27 described above are controlled by the controller 17 as a whole.

Next, the two-fluid nozzle 7 will be described with reference to FIG. The mixing part 29 in the two-fluid nozzle 7 has a structure in which the supply pipe 15a surrounds the outside of the gas introduction pipe 15b via the support part 31, that is, the gas introduction pipe 15b is inserted in the supply pipe 15a. It is composed of a heavy pipe structure. Further, the tip portion 33 of the two-fluid nozzle 7 is constituted by connecting an orifice-shaped tube and an accelerating tube which is a straight cylindrical tube for accelerating the mist M. In this embodiment, the inner diameter φ of the discharge port at the tip portion 33 is 3.3 mm.

The two-fluid nozzle 7 may have a structure in which the gas introduction pipe 15b surrounds the outside of the supply pipe 15a, in addition to the structure in which the outside of the gas introduction pipe 15b is surrounded by the supply pipe 15a as described above. The inner diameter φ of the discharge port is 3.
It is not limited to 3 mm.

The amount of the gas G used in the two-fluid nozzle 7 is in the range of 20 L / min to 100 L / min,
More preferably, 20 L / min to 60 L / min
The range is up to. The amount of the cleaning liquid S used in the two-fluid nozzle 7 is in the range of 10 mL / min to 200 mL / min, preferably 100 mL / min to 200 m.
Range up to L / min, more preferably 100 mL /
The range is from min to 150 mL / min. Within the above range, the particles can be suitably removed without damaging the pattern.

Next, the operation of the substrate cleaning apparatus having the above structure will be described. As the cleaning condition, the distance L from the discharge port for discharging the mist-cleaned cleaning liquid S to the processing surface of the substrate W is 10 mm, and the amount of the gas G used is 6
0 L / min, the amount of cleaning liquid S used is 150 mL
/ Min. Then, at this time, the droplet size of the formed mist cleaning liquid S is controlled in the range of 5 μm to 20 μm. First, the shatterproof cup 9 is lowered with respect to the spin chuck 1, and the patterned substrate W is placed on the spin chuck 1. Then, the scattering prevention cup 9 is raised and the two-fluid nozzle 7 is moved to the cleaning position. Next, while rotating the substrate W at a constant speed at a low speed, the mist M is supplied to the substrate W from the two-fluid nozzle 7, and the mist M is hit on the substrate W. After performing the cleaning process for a certain time in the above-described state, the discharge of the mist M is stopped and the two-fluid nozzle 7 is moved to the standby position. At the same time, the substrate W is rotated at a high speed to scatter the washed cleaning liquid S to the surroundings, and the substrate W is shaken off and dried to complete a series of cleaning processes. The rotation speed of the substrate W during low-speed rotation is, for example, 50.
It is 0 rpm.

When the two-fluid nozzle 7 is swung on the processing surface of the substrate W, the periphery of the substrate W-the center of rotation P-
The number of times the substrate W is scanned, such as the edge,
For example, it is set to twice and the scanning speed of the two-fluid nozzle 7 is set to 5 mm / sec.

By using the above-mentioned two-fluid nozzle 7 to clean the patterned substrate W, particles can be removed without damaging the pattern. In particular, the cleaning process can be performed without collapsing the convex pattern.

Further, as a cleaning condition, the distance L from the discharge port for discharging the mist-ized cleaning liquid S to the processing surface of the substrate W is 10 mm, and the amount of the gas G used is 60 L / m.
and the amount of the cleaning liquid S used is 150 mL / min
Is. The distance L is in the range of 5 mm to 10 mm, and the amount of gas G used is 20 L / min to 100 L / min.
Within the range of min, preferably 20 L / min to 6
Within the range of 0 L / min, the usage amount of the cleaning liquid S is within the range of 10 mL / min to 200 mL / min, preferably 100 mL / min to 200 mL / m.
within a range up to in, more preferably 100 mL / mi
It is within the range from n to 150 mL / min. Therefore, since the cleaning conditions are within these ranges, it is possible to preferably remove the particles without damaging the pattern.

That is, if the amount of the gas G or the cleaning liquid S used is larger than these ranges, the cleaning power becomes large and the pattern is damaged. If it is smaller than these ranges, the cleaning power becomes small and particles are not sufficiently removed. Was confirmed.

Furthermore, since ultrapure water to which carbon dioxide is added is used as the cleaning liquid S, the dielectric breakdown of the substrate W can be prevented. Moreover, since nitrogen (N ₂ ) which is an inert gas is used as the gas G, the cleaning liquid S, the substrate W, and the pattern are not adversely affected.

The present invention is not limited to the above embodiment, but can be modified as follows.

(1) In this embodiment described above, the substrate W on which the pattern is formed is formed in a separate apparatus (not shown) for forming the pattern, for example, performing the photolithography process or the vapor deposition process. Then, the substrate was transferred to the substrate cleaning apparatus according to this example and further cleaned using a two-fluid nozzle. Furthermore, since the above-mentioned separate apparatus can perform the cleaning process and the drying process, the cleaning process in this case includes the cleaning process by the two-fluid nozzle of this embodiment and the cleaning process by the separate device. The number of times is two, but only cleaning with a two-fluid nozzle may be performed. For example, a two-fluid nozzle may be provided in the separate apparatus described above, and the patterned substrate W may be cleaned by the two-fluid nozzle in the apparatus and then dried. As described above, even if the cleaning is performed only once, the same effect as that of the present embodiment can be obtained as long as the cleaning is performed by the two-fluid nozzle. Further, when the above-mentioned separate device is provided with the two-fluid nozzle, the device itself can be simplified.

[0035]

As is apparent from the above description, according to the present invention, by cleaning the patterned substrate using the two-fluid nozzle, particles are removed without damaging the pattern. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a substrate cleaning apparatus used in a substrate cleaning method according to an embodiment.

FIG. 2 is a vertical cross-sectional view showing the configuration of a two-fluid nozzle according to this embodiment.

FIG. 3 is an explanatory diagram showing a conventional patterned substrate.

[Explanation of symbols]

W ... Substrate S ... Cleaning liquid G ... gas M ... Mist 1… Spin chuck 7 ... 2-fluid nozzle 21 ... Ultrapure water equipment 27 ... Gas supply device

Front page continuation (51) Int.Cl. ⁷ identification code FI theme code (reference) G02F 1/13 101 G02F 1/13 101 1/1333 500 1/1333 500 G11B 7/26 G11B 7/26 (72) Invention Person Masanobu Sato 4-chome, Tenjin Kitamachi, 1-chome, Horikawa-dori Teranouchi, Kamigyo-ku, Kyoto 1 Japan Nippon Screen Manufacturing Co., Ltd. (72) Inventor Hayato Iwamoto 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony shares In-house (72) Inventor Hajime Ugagami 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony F-term (reference) 2H088 FA21 FA30 HA01 MA20 2H090 HC18 JB02 JB04 JC19 3B201 AA01 AB02 AB33 BA06 BB21 BB38 BB92 BB99 CC13 5D121 GG11 GG16 GG18

Claims (10)

[Claims] 1. A two-fluid nozzle that mixes a cleaning liquid and a pressurized gas inside a nozzle to form a mist and discharges the formed mist from a discharge port at the tip of the nozzle,
A method for cleaning a substrate, comprising: cleaning a substrate;
Mist is formed by supplying the mist by supplying the mist to the substrate on which the pattern is formed, and the substrate is cleaned. Characteristic substrate cleaning method. 2. The substrate cleaning method according to claim 1, wherein the substrate has a convex pattern. 3. The substrate cleaning method according to claim 1, wherein the amount of gas using the gas in the two-fluid nozzle is in the range of 20 L / min to 60 L / min. Substrate cleaning method. 4. The substrate cleaning method according to claim 1, wherein the amount of the liquid that uses the cleaning liquid in the two-fluid nozzle is in the range of 10 mL / min to 200 mL / min. A method of cleaning a substrate, comprising: 5. The substrate cleaning method according to claim 1, wherein an amount of the liquid using the cleaning liquid in the two-fluid nozzle is in a range of 100 mL / min to 200 mL / min. A method of cleaning a substrate, comprising: 6. The substrate cleaning method according to claim 1, wherein an amount of the liquid that uses the cleaning liquid in the two-fluid nozzle is in a range of 100 mL / min to 150 mL / min. A method of cleaning a substrate, comprising: 7. The substrate cleaning method according to claim 1, wherein the cleaning liquid is pure water to which carbon dioxide (CO ₂ ) is added. 8. The substrate cleaning method according to claim 1, wherein the gas is an inert gas. 9. The substrate cleaning method according to claim 1, wherein a distance from a discharge port for discharging the mist in the two-fluid nozzle to a processing surface of the substrate is 5 mm to 10 mm.
A method for cleaning a substrate, which is in a range up to mm. 10. The substrate cleaning method according to claim 1, wherein the droplet size of the mist is in the range of 5 μm to 20 μm.