JP3351082B2 - Substrate drying method, substrate drying tank, wafer cleaning apparatus, and method of manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a substrate drying method and a substrate drying tank.
And a method for manufacturing a wafer cleaning apparatus and a semiconductor device.
I do.

[0002]

2. Description of the Related Art The miniaturization of semiconductor devices has been rapidly progressing, and the memory capacity has continued to increase to 64 MDRAM, 256 MDRAM, and so on, and research and development therefor are actively proceeding.

[0003] Under such circumstances, the wafer cleaning technology has become a very important technology in ensuring the reliability of devices and the product yield in the future. In particular, particles having a minimum pattern size of about 1/10 are said to affect the product yield, and with the miniaturization of devices, the requirements for cleaning devices have become more severe.

As a general method of cleaning a wafer, R
There is a CA cleaning method, and as a device for performing the cleaning method, a batch-type wet cleaning device has been mainly used. However, there are problems such as an increase in the size of the apparatus (increase in footprint) due to an increase in the diameter of the wafer, contamination of the wafer surface from the back surface of the wafer, and the single-wafer type automatic cleaning machine is also being reviewed.

As a method of cleaning a wafer, a method of spraying a chemical solution while rotating the wafer has been known to have an excellent particle removing effect and metal contamination effect (see Breakthrough by Realize Inc.). THROUGH) 1993 8-9 No. 37-38
page).

As shown in FIG. 3, a single wafer type automatic wafer cleaning apparatus 10 has a first cleaning tank 2, a second cleaning tank 4, and a rinsing and drying tank 6. The first cleaning tank 2 is a cleaning tank for cleaning the wafer 8 with an alkaline chemical solution.
The first cleaning nozzles 12a are mounted.

[0007] The first cleaning nozzles 12a, 12a are mounted on both sides of the wafer 8, and are, for example, ammonia-free.
Alkaline chemicals such as hydrogen peroxide are sprayable on both sides of the wafer. A first spray of pure water on both sides of the wafer 8 is performed on both sides of the wafer 8.
Pure water nozzles 14a, 14a are also arranged.

The wafer 8 transferred to the first cleaning tank 2 is
It is held by a rotatable first rotary chuck 16a. First
The rotary chuck 16a is configured so that the back surface of the wafer 8 can be sprayed. The wafer 8 is the first
It is carried into the cleaning tank 2 using a transfer arm or the like. First
The wafer 8 held by the rotary chuck 16a has a capacity of about 10
The spraying of ammonia-hydrogen peroxide is performed from the first cleaning nozzle 12a while rotating at a rotation speed of 00 rpm, and then the pure water is sprayed from the first pure water nozzle 14a in the same tank 2 to obtain a coarse rinse. Processing is performed.

The second cleaning tank 4 is a cleaning tank for cleaning the wafer 8 with an acidic chemical solution. Inside the tank 4, second cleaning nozzles 12b, 12b and third cleaning nozzles 12c, 12c are mounted. The second cleaning nozzles 12b, 12b are mounted on both sides of the wafer 8, and are arranged so that an acidic chemical such as hydrochloric acid-hydrogen peroxide can be sprayed on both sides of the wafer. The third cleaning nozzles 12c, 12c are mounted at both surface positions of the wafer 8, for example, DHF
An acidic chemical such as (dilute hydrofluoric acid) or BHF (such as buffered hydrofluoric acid or ammonium fluoride) is arranged to be sprayable on both surfaces of the wafer. Second pure water nozzles 14b, 14b for spraying pure water on both surfaces of the wafer 8 are also arranged at both surface positions of the wafer 8.

The wafer 8 transferred from the first cleaning tank 2 to the second cleaning tank 4 is held by a rotatable second rotary chuck 16b. The second rotary chuck 16b is configured so that the back surface of the wafer 8 can be sprayed. The wafer 8 is carried from the first cleaning tank 2 into the second cleaning tank 4 using a robot hand or the like. Second rotating chuck 1
The wafer 8 held by 6b is sprayed with a chemical solution from the second cleaning nozzle 12b and the third cleaning nozzle 12c while being rotated at a rotation speed of about 1000 rpm. Naturally, during the chemical treatment, pure water is sprayed from the second pure water nozzle 14b to perform a rough rinsing treatment.

The rinsing / drying tank 6 is a tank for rinsing the wafer 8 and then drying the wafer 8. Inside the tank 6, third pure water nozzles 14c and 14c and a fourth pure water nozzle 14d are mounted. . The third pure water nozzles 14c, 14c are mounted on both sides of the wafer 8, and are arranged so that pure water can be sprayed on both sides of the wafer. Fourth pure water nozzle 14
d is Yes and attached to the upper surface position of the wafer 8, are small vibrations (about 1 MH _Z) is pure water added (M-Sonic) arranged to be sprayed on the upper surface of the wafer.

The wafer 8 transferred from the second cleaning tank 4 to the rinsing / drying tank 6 is rotated by a third rotating chuck 16.
c. The third rotary chuck 16c is configured so that the back surface of the wafer 8 can be sprayed. The wafer 8 is transferred from the second cleaning tank 4 to the rinsing and drying tank 6.
It is carried in using a robot hand or the like.

The wafer 8 held by the third rotary chuck 16c is sprayed with pure water from the pure water nozzles 14c and 14d while rotating at about 1000 rpm, and is subjected to a final rinsing process to sufficiently remove the remaining chemical. Thereafter, the wafer is rotated at a high speed of about 3000 rpm to shake off and dry the water.

Finally, the dried wafer 8 is carried out to the unloader, and one cycle of the wafer cleaning and drying steps is completed. In the single wafer cleaning apparatus 10, the wafer 8
Is sent into each of the tanks 2, 4, and 6 one by one.

[0015]

In the spin drying process of the wafer performed in the rinsing / drying tank 6, FIG.
As shown in (a), since the water droplets 18 on the wafer 8 are blown off and dried by the centrifugal force generated when the wafer rotates,
The dry state changes greatly depending on whether the surface of the wafer 8 is hydrophilic or hydrophobic. The silicon oxide film is a hydrophilic surface, but the surfaces of the silicon substrate and the polysilicon film are hydrophobic surfaces.
When the surface of the wafer is a hydrophobic surface, water droplets are likely to remain at the center of the wafer where centrifugal force cannot be obtained, and poor drying tends to occur.

Therefore, by rotating the upper surface of the wafer at an extremely low speed (about 70 rpm) before spin drying, water droplets at the center of the wafer are moved in the peripheral direction to prevent poor drying. However, as for the back surface (lower surface) of the wafer 8, as shown in FIG. 4B, the weight of the water droplet 18 also acts, and even at a low speed rotation, the water droplet 18 does not move to the periphery, resulting in poor drying and poor drying. This causes an increase in the number of particles.

If there is defective drying of the wafer, moisture mist adheres to the surface of the wafer adjacent to the defectively dried wafer, and the wafer remains as minute particles and haze. Therefore, when, for example, a CVD film is formed on the wafer in the next step, there is a possibility that the flatness of the surface is adversely affected, and problems such as abnormal growth of particles constituting the film occur.

Japanese Patent Application Laid-Open No. 4-122024 discloses that in order to enhance the cleaning effect of a wafer, I
A configuration for discharging a mixed vapor containing PA vapor to a wafer is disclosed. However, the technique disclosed in this publication is a technique for improving the cleaning effect by discharging a mixed vapor with IPA to a wafer, and cannot be used for a method for drying a wafer.

[0019] The present invention has been made in view of such circumstances, the substrate drying method both sides of a substrate such as a wafer Ru can be satisfactorily and short time drying, and the substrate drying chamber,
Provided are a wafer cleaning apparatus and a method for manufacturing a semiconductor device.
The porpose is to do.

[0020]

In order to achieve the above object, a substrate drying method of the present invention is a method of drying a substrate in a single-wafer manner, wherein water droplets existing on the surface of the substrate to be dried are removed. Rotating the substrate at a first rotation speed capable of moving in the direction, and rotating the substrate at a second rotation speed higher than the first rotation speed, at least toward the back surface of the substrate. Discharging alcohol-based vapor. As the alcohol-based vapor, an alcohol-based vapor that is arbitrarily mixed with water is preferable, and methyl alcohol, ethyl alcohol, and isopropyl alcohol (hereinafter, sometimes simply referred to as “IPA”) can be used. preferable. IP
A is preferably inexpensive, high in purity,
This is for safety reasons. The first rotation speed is, for example, 100 rpm or less, preferably 80 rpm.
m, more preferably 70 rpm or less. The second rotation speed is, for example, 1000 r
pm or more, preferably 2000 rpm or more, and more preferably 3000 rpm or more. In the present invention, “discharge” is used in a broad concept including spray processing.

Preferably, after the step of discharging the alcohol-based vapor, a step of rotating the substrate at a third rotation speed higher than the first rotation speed without discharging the alcohol-based vapor. Have more. In this case, the third rotation speed of the substrate is, for example, 1000 rpm or more,
Preferably, it is 2000 rpm or more, more preferably 3 rpm.
000 rpm or more.

In the step of discharging the alcohol-based vapor,
Discharge the alcohol-based vapor at a temperature equal to or higher than the boiling point.
You.

Furthermore, in order to achieve the above object, the present invention
Ming's substrate drying tank is a rotating means that rotates substrates one by one.
And alcohol-based steam at least toward the back side of the substrate.
Steam nozzle means for discharging air, and the alcohol-based steam
And a collecting means for collecting the In addition, the front and back of the substrate
Further has a pure water nozzle means for discharging pure water to the surface
Preferably.

Further, in order to achieve the above object, the present invention
Ming's wafer cleaning system is designed to rotate substrates one by one.
And a rotating means for discharging a cleaning liquid onto the front and back surfaces of the substrate.
A substrate cleaning tank having a cleaning nozzle
A second rotating means for rotating the substrate one by one;
At least a steam nozzle that discharges alcohol-based steam toward the back
Slurry means and recovery means for recovering the alcohol-based vapor
And a substrate drying tank having:

Further, in order to achieve the above object, the present invention
The method of manufacturing a semiconductor device according to
A method of manufacturing a semiconductor device having a drying step, comprising:
Water droplets on the surface of the semiconductor device to be dried
At a first rotational speed capable of moving the semiconductor device in the
Rotating, and a second rotation speed higher than the first rotation speed.
While rotating the semiconductor device at a rotation speed of
Apply alcohol-based vapor at least to the back of the conductor device.
Discharging step.

[0026]

In the substrate cleaning method according to the present invention, since alcohol-based vapor is discharged to the substrate to be dried, the alcohol-based vapor causes a condensation reaction, effectively takes in moisture into the condensed liquid film, and improves the drying capacity. Improve.

If alcohol-based vapor such as IPA is discharged while rotating the substrate, a centrifugal force due to the rotation is also given, so that the drying ability is further improved, and poor drying of the substrate can be prevented. By rotating the substrate at a relatively low speed before discharging alcohol-based vapor, water droplets attached to the surface of the substrate can be moved in the peripheral direction. Water droplets adhering to the upper surface of the substrate can be removed without discharging system vapor. Water droplets adhering to the back surface of the substrate may still remain, but can be effectively removed by discharging the alcohol-based vapor while rotating the substrate.

By discharging the alcohol-based vapor only to the back surface of the substrate, the amount of the alcohol-based vapor used can be reduced, and the supply and recovery costs can be reduced. After discharging the alcohol vapors, by performing only a relatively fast spin drying, it is possible to perform the spin drying in the alcoholic vapor atmosphere, it is possible to reduce the charging phenomenon due to friction with air substrate. Further, since the alcohol-based vapor atmosphere is replaced with fresh air, safety when the acid chamber is close can be ensured.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a wafer rinsing and drying tank according to one embodiment of the present invention, and FIG.
(A)-(d) is the schematic which shows a rinsing process and a drying process.

A rinsing and drying tank 20 according to an embodiment of the present invention shown in FIG. 1 is provided instead of the rinsing and drying tank 6 of the cleaning apparatus 10 shown in FIG. Since the configurations of the first cleaning tank 2 and the second cleaning tank 4 of the cleaning device 10 have already been described, the description thereof will be omitted.

The rinsing and drying tank 20 according to the present embodiment is a tank for rinsing the wafer 8 and then drying it.
0, the third pure water nozzles 14c, 14c and the fourth
A pure water nozzle 14d is mounted. Third pure water nozzle 14
c and 14c are mounted on both sides of the wafer 8,
Pure water is sprayable on both sides of the wafer.
The fourth water nozzle 14d is Yes and attached to the upper surface position of the wafer 8, there are small vibrations (about 1 MH _Z) is pure water added (M-Sonic) arranged to be sprayed on the upper surface of the wafer . Note that the fourth pure water nozzle 14d may be arranged at both surface positions of the wafer.

In the present embodiment, a steam nozzle 22 is arranged inside the rinsing / drying tank 20 so as to discharge IPA vapor at least to the rear surface position of the wafer. From this steam nozzle 22, IPA steam heated to a boiling point of IPA or higher can be discharged. The temperature of the IPA vapor is not particularly limited, but is about 80 to 98 ° C.

As shown in FIG. 5, the rinsing / drying tank 20 is preferably provided with an IPA vapor recovery mechanism 30. The collection mechanism 30 includes a cooling pipe (for example, a quartz tube) 32 disposed at an upper portion in the tank 20, a receiving portion 33 disposed at a lower portion thereof, and an IPA disposed outside the tank 20.
And a temperature control tank 34. In the temperature control tank 34, the IPA is heated to an appropriate temperature by a heater. The IPA in the temperature control tank 34 can be configured to return to the steam nozzle 22 through an air valve 36 and a spray pump 38. A filter may be arranged in the path. With this recovery mechanism 30, the amount of IPA vapor used can be reduced, which contributes to a reduction in manufacturing costs.

The wafer 8 transferred from the second cleaning tank 4 shown in FIG. 3 to the rinsing / drying tank 20 is held by a rotatable third rotary chuck 16c. Third rotary chuck 16c
Is configured so that the back surface of the wafer 8 can be sprayed. The wafer 8 is placed in the second cleaning tank 4 shown in FIG.
From the rinsing and drying tank 20 shown in FIG. 1 using a robot hand or the like. Fresh clean air is always introduced into the rinsing / drying tank 20.

First cleaning tank 2 and second cleaning tank shown in FIG.
The wafer 8 cleaned in step 4 is sent into the rinsing and drying tank 20 shown in FIG.
c. Therefore, the wafer 8 is firstly
As shown in (a), while rotating at about 1000 rpm or less, pure water is sprayed from the pure water nozzles 14c and 14d, and a final rinsing process is performed to sufficiently remove the remaining chemical. Thereafter, as shown in FIG. 2B, the wafer 8 is rotated at a low speed of about 70 rpm or less for about 2 to 3 seconds to move the water droplet 18 on the surface of the wafer 8 to a position where a centrifugal force acts.

Thereafter, as shown in FIG. 2C, while the high-temperature (80 to 98 ° C.) IPA vapor is discharged from the IPA vapor nozzle 22 installed on the back side of the wafer 8, the rotation speed of the wafer 8 is increased. Is raised to about 3000 rpm or less in 2 to 3 seconds, and spin drying is continued for about 30 seconds. As a result, the IPA vapor discharged on the back surface of the wafer causes a condensation reaction, effectively taking in moisture into the condensed film, and improving the drying ability. In addition, as shown in FIG. 2D, a centrifugal force due to rotation of about 3000 rpm is also applied, so that the drying ability is further improved, and even on a wafer having a hydrophobic surface, poor drying on the back surface of the wafer is eliminated.

Finally, the dried wafer 8 is carried out to the unloader, and one cycle of the wafer cleaning and drying steps is completed. Next, a method of drying a wafer according to another embodiment of the present invention will be described. In the present embodiment, the wafer 8 cleaned in the first cleaning tank 2 and the second cleaning tank 4 shown in FIG. 3 is held on the third rotary chuck 16c of the rinsing and drying tank 20 shown in FIG. As shown in FIG. 2A, pure water is sprayed from the pure water nozzles 14c and 14d while rotating at a speed of about 1000 rpm or less, and a final rinsing process is performed to sufficiently remove the remaining chemical solution. Then, FIG.
As shown in (b), at a low speed of about 70 rpm or less,
The wafer 8 is rotated for about 2 to 3 seconds, and the water droplet 18 on the surface of the wafer 8 is moved to a position where a centrifugal force acts.

Thereafter, as shown in FIG. 2C, while the high-temperature (80 to 98 ° C.) IPA vapor is discharged from the IPA vapor nozzle 22 installed on the back side of the wafer 8, the rotation speed of the wafer 8 is increased. Is raised to about 3000 rpm or less in 2 to 3 seconds, and spin drying is continued for about 15 seconds while discharging IPA vapor. Thereafter, the discharge of the IPA vapor from the vapor nozzle 22 is stopped, and only spin drying is performed for about 15 seconds as shown in FIG.

As a result, the IP discharged on the back surface of the wafer
The A vapor causes a condensation reaction, effectively taking in moisture into the condensed film and improving the drying ability. 3000 rpm
Since a centrifugal force due to rotation of about m is also given, the drying ability is further improved, and even on a wafer having a hydrophobic surface, poor drying on the back surface of the wafer is eliminated.

[0040] Furthermore, in this embodiment, it becomes possible to perform the spin drying in the atmosphere of IPA vapor, it is possible to reduce the charging phenomenon due to friction with the air of the wafer. Also, I
Since the PA vapor atmosphere is replaced with fresh air, safety when the acid chamber (the second cleaning tank 4 shown in FIG. 3) is nearby can be ensured.

Finally, the dried wafer 8 is carried out to the unloader, and one cycle of the wafer cleaning and drying steps is completed. Note that the present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention.

For example, the substrate drying method and the drying tank according to the present invention can be applied not only to a wafer cleaning apparatus but also to other apparatuses requiring a wafer drying step. Further, the method and apparatus according to the present invention can be used as a method for drying a disk substrate other than a wafer, an apparatus for drying, and a cleaning apparatus in the same manner as in the case of a wafer.

[0043]

As described above, according to the present invention, it is possible to effectively prevent poor drying on the front and back surfaces of a substrate having a hydrophobic surface, particularly on the back surface, and obtain a clean substrate. Therefore, particles and haze after the substrate is dried are eliminated, and abnormal growth of the deposited film and deterioration of flatness due to the particles and haze are eliminated.

In addition, charging of the substrate surface can be prevented, and adhesion of particles can be reduced. As a result, the production yield of the semiconductor device on the substrate is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a wafer rinsing and drying tank according to one embodiment of the present invention.

FIGS. 2A to 2D are schematic views showing a rinsing step and a drying step.

FIG. 3 is a schematic sectional view of the entire wafer cleaning apparatus.

4 (a) and 4 (b) are schematic diagrams showing problems in a conventional drying tank.

FIG. 5 is a schematic cross-sectional view of a wafer rinsing and drying tank according to another embodiment of the present invention having an IPA recovery mechanism.

[Explanation of symbols]

 2 First cleaning tank 4 Second cleaning tank 6, 20 Rinse and drying chamber 8 Wafer 10 Wafer cleaning device 12a, 12b, 12c Cleaning nozzle 14a, 14b, 14c, 14d Pure water nozzle 16a, 16b , 16c Rotary chuck 22 Steam nozzle 30 Recovery mechanism

Claims (11)

(57) [Claims] A 1. A method of drying a substrate in single wafer, the water droplets on the surface of the substrate to be dried in the peripheral direction
Rotating the substrate at a first rotational speed that can be moved;
And a step of rotating the base at a second rotation speed higher than the first rotation speed.
While rotating the board, face at least the back side of the substrate
Substrate drying method and a step of discharging the alcohol vapors Te. 2. After the step of discharging the alcohol-based vapor.
Without discharging the alcohol-based vapor,
Rotating the substrate at a third rotation speed higher than the first rotation speed;
The method for drying a substrate according to claim 1, further comprising a step of rotating the substrate. 3. The method according to claim 2, wherein the alcohol-based vapor is discharged.
And discharging isopropyl alcohol vapor.
Or the substrate drying method according to 2. 4. The method according to claim 1, wherein the alcohol-based vapor is discharged.
Discharge the alcohol-based vapor at a temperature equal to or higher than the boiling point.
The method for drying a substrate according to claim 1. 5. A rotating means for rotating substrates one by one, and an alcohol-based vapor toward at least a back surface of the substrate.
A base having a steam nozzle means for discharging and a collecting means for collecting the alcohol-based vapor
Plate drying tank . 6. A method for discharging pure water to the front and back surfaces of the substrate.
The substrate drying device according to claim 5, further comprising a pure water nozzle means.
Drying tank. 7. A first rotating means for rotating substrates one by one.
If, on the front and back surfaces of the substrate, cleaning nozzle means for discharging a washing liquid
And a second rotating means for rotating the substrate one by one, and applying alcohol-based vapor toward at least the back surface of the substrate.
A base having a steam nozzle means for discharging and a collecting means for collecting the alcohol-based vapor
A wafer cleaning apparatus having a plate drying tank . 8. A method for drying a semiconductor device in a single wafer mode.
A method for manufacturing a semiconductor device, comprising: removing water droplets present on the surface of the semiconductor device to be dried;
The semiconductor device at a first rotational speed capable of moving the semiconductor device
Rotating the semiconductor device at a second rotation speed higher than the first rotation speed.
While rotating the conductor device, at least the semiconductor device
Even toward the rear surface closed and the step of discharging the alcohol vapors
Semiconductor device manufacturing method. 9. After the step of discharging the alcohol-based vapor.
Without discharging the alcohol-based vapor,
The semiconductor device at a third rotation speed higher than the first rotation speed;
9. The half of claim 8, further comprising rotating the device.
A method for manufacturing a conductor device. 10. The method according to claim 10, wherein the alcohol-based vapor is discharged.
Wherein isopropyl alcohol vapor is discharged.
10. The method for manufacturing a semiconductor device according to 8 or 9. 11. The method according to claim 11, wherein the alcohol-based vapor is discharged.
Discharge the alcohol-based vapor at a temperature equal to or higher than the boiling point.
A method of manufacturing a semiconductor device according to claim 8.
Construction method.