JPH06310486A - Method and apparatus for drying substrate - Google Patents

Abstract

PURPOSE:To efficiently dry a substrate with reliability by spraying the vapor of water-soluble alcohol on the surface of the substrate being rotated. CONSTITUTION:A gas feed path 30 consists of a pipe 33 that connects a nitrogen gas inlet 31 and the gas spray nozzle 13 in a substrate processing section 10. The pipe 33 is midway connected to a bath 35 with isopropyl alcohol(IPA), a water-soluble alcohol, stored therein. The bath 35 is equipped outside its bottom with a heater 37, which heats the bath 35 to produce the vapor of IPA. The produced vapor is mixed with nitrogen gas passing through the pipe 33, and the resultant gas mixture is sprayed on a substrate W through the gas spray nozzle 13. The nozzle 13 is directed so that the gas mixture will be sprayed toward the center of the rotation of the substrate W surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate to be processed such as a semiconductor substrate or a glass substrate for liquid crystal (hereinafter, simply referred to as substrate).
The present invention relates to a substrate drying method for drying a substrate and a substrate drying apparatus used in this method.

[0002]

2. Description of the Related Art Generally, a semiconductor manufacturing process includes a drying step of drying a cleaned substrate.
As a drying method for realizing this drying step, a centrifugal dehydration method in which a substrate is rotated and water droplets on the substrate are blown off by a centrifugal force due to the rotation is well known.

In this centrifugal dehydration type, there has been proposed a structure in which air is blown onto the surface of the substrate for the purpose of more efficient drying (Japanese Patent Publication No. 62-62-62).
53942, etc.). That is, more efficient drying is realized by blowing off the water droplets adhering to the substrate surface by the air blown in addition to the centrifugal force generated by the rotation of the substrate. Further, a structure has also been proposed in which nitrogen gas is blown onto the substrate surface instead of the air (Japanese Patent Laid-Open No. 57-42).
No. 121).

On the other hand, as a substrate drying method, in addition to the centrifugal dehydration method, an IPA vapor method has been proposed. In this method, the substrate is placed in an atmosphere of vapor (vapor) of isopropyl alcohol (IPA) to replace water attached to the substrate with the vapor of IPA for dehydration.

[0005]

However, all of the above-mentioned conventional techniques have a problem that it takes a considerable amount of time to dry the moisture on the substrate and the drying efficiency is poor. In particular, in the centrifugal dehydration type substrate drying method, since the action of the centrifugal force is small in the rotation center portion of the substrate surface, the water drainage is poor, and water residue easily occurs in the center portion.

The substrate drying method and the substrate drying apparatus of the present invention have been made in order to solve the above-mentioned problems in the prior art, and an object thereof is to dry a substrate efficiently and surely.

[0007]

In order to achieve such an object, as a means for solving the above-mentioned problems, in the substrate drying method according to the first invention, the substrate is rotated and adhered to the surface of the substrate. A method of drying a substrate in which water drops are drained and dried is characterized in that a vapor of a water-soluble alcohol is sprayed onto the surface of the rotating substrate. Further, in the substrate drying method according to the second aspect of the invention, in the configuration of the first aspect of the invention, the vapor spraying direction is a direction toward the center of rotation of the substrate surface.

Further, a substrate drying device according to a third aspect of the invention is the substrate drying device used in the first aspect of the invention, wherein a substrate rotating means for holding and rotating the substrate and a vapor of water-soluble alcohol are generated. It is characterized in that it is provided with a vapor generating means for causing it and a supplying means for supplying the vapor of the water-soluble alcohol generated in the vapor generating part to the surface of the substrate held by the substrate rotating means.

[0009]

In the substrate drying method according to the first aspect of the invention configured as described above, in addition to the centrifugal force generated by rotating the substrate, the water droplets on the substrate surface are blown off by spraying the vapor of the water-soluble alcohol. Further, since the water-soluble alcohol vapor sprayed on the substrate surface is partially dissolved in the water droplets on the substrate surface, the surface tension of the water droplets is lowered, and the liquid drop of the water droplets during rotation of the substrate is improved. Further, the vapor of alcohol dissolved in the water droplets raises the vapor pressure of the water droplets and evaporates the water droplets together with the alcohol content.

The substrate drying method according to the second invention is
More efficient drying can be performed on the center of rotation where water is poorly drained. Furthermore, according to the substrate drying apparatus of the third invention, the methods of the first and second inventions are effectively implemented.

[0011]

Preferred embodiments of the present invention will be described below in order to further clarify the constitution and operation of the present invention described above. FIG. 1 is a schematic configuration diagram of a rotary substrate processing apparatus 1 as a first embodiment of the present invention.

As shown in FIG. 1, the rotary substrate processing apparatus 1 includes a substrate processing section 10 for performing a drying process on a semiconductor substrate (simply referred to as a substrate) W and an isopropyl alcohol (IPA) vapor. A gas supply unit 30 that introduces nitrogen gas into the substrate processing unit 10.

The substrate processing unit 10 holds the substrate W and rotates horizontally at a predetermined rotation speed, and a nitrogen gas which is arranged above the substrate W and is supplied from a gas supply unit toward the substrate W. A gas spray nozzle 13 for spraying,
A scattering prevention member 15 that surrounds the horizontally rotating substrate W and prevents scattering of water droplets blown off from the substrate W, a processing container 17 that houses the spin chuck 11, the gas spray nozzle 13, and the scattering prevention member 15, and a processing container 17 An upper lid 19 disposed on the upper part of the container for taking in outside air, and a processing container 1
7 is provided with a forced exhaust port 21 attached to the lower wall and a drive motor 23 that rotationally drives the spin chuck 11.

As shown in FIG. 2, the spin chuck 11 has four arms 11b extending radially around the rotation base 11a, and the outer edge of the disk-shaped substrate W is provided at the tip of each arm 11b. Is provided with a stepped portion 11c. According to this spin chuck 11, the substrate W is
The substrate W is arranged horizontally on the book arm 11b, and is positioned concentrically with the rotation shaft 11d by each step 11c to hold the substrate W. When the drive motor 23 is rotationally driven, the drive motor 23
The spin chuck 11 is connected via a rotating shaft 11d connected to
Rotates and the substrate W rotates. In the substrate processing unit 10 having such a configuration, the air in the processing container 17 can be forcibly discharged from the forced exhaust port 21.

On the other hand, the gas supply unit 30 is provided with a pipe line 33 extending from a nitrogen gas inlet 31 for feeding nitrogen gas to the gas spray nozzle 13 of the substrate processing unit 10, and the pipe line 3 thereof.
In the middle of 3, a tank 35 storing the IPA liquid is connected. Further, a heater 37 is provided outside the bottom of the tank 35, and the heater 37 heats the tank 35 to cause the IP.
A vapor of A is generated. The generated vapor is mixed with the nitrogen gas flowing through the pipe 33 and is discharged from the gas spray nozzle 13 toward the substrate W together with the nitrogen gas. The blowing direction of the gas blowing nozzle 13 is set to the substrate W.
It is the direction toward the center of rotation of the surface.

Further, the IPA liquid in the tank 35 is provided with a liquid temperature sensor 41 for detecting the temperature in the liquid, and the detection signal of the liquid temperature sensor 41 is inputted to the temperature adjusting section 43. The temperature control unit 43 controls ON / OFF of energization to the heater 37 by controlling ON / OFF of the thyristor 45 according to the detection signal of the liquid temperature sensor 41, and as a result, the bath 35
The temperature of the IPA liquid is adjusted to a constant temperature, for example 70 degrees.

In the rotary substrate processing apparatus 1 having such a structure, in addition to the above-described drying process for the substrate W, the substrate W is rinsed with pure water as a pre-process.
A water washing process is performed to wash the water. In this process of washing with water, a pure water spray nozzle (not shown) is prepared in the processing container 17, and a pure water supply unit (not shown) for supplying pure water to the pure water spray nozzle is prepared. The pure water is rinsed onto the substrate W.

Next, how the rotation speed of the substrate W can be changed from the water washing process to the drying process will be described. As shown in FIG. 3, the rotation speed of the substrate W gradually increases with the start of the water washing process, and then the rotation speed R becomes constant.
Is kept at 1. After that, when the washing process is transferred to the drying process, the rotation speed of the substrate W further increases and is kept at a predetermined rotation speed R2 higher than the rotation speed R1. After that, when the drying process is completed, the rotation speed of the substrate W is gradually reduced. With this configuration, the draining and drying process is performed at a higher rotation speed than that during washing with water.

In this embodiment, as shown in FIG. 3, the rinsing of pure water is started at the start of the water washing process and the rinsing of pure water is finished at the end of the water washing process. Further, the spraying of the IPA vapor is started at the start of the drying step, and the spraying is finished at the end of the drying step.

The configuration of the first embodiment has been described in detail above. According to the first embodiment, in addition to the centrifugal force generated by the rotation of the substrate W, the nitrogen containing IPA vapor on the surface of the substrate W is added. Water droplets on the surface of the substrate W are blown off by blowing gas. Furthermore, IPA sprayed on the surface of the substrate W
Since a part of the vapor is dissolved in the water droplets on the surface of the substrate W, the surface tension of the water droplets is lowered, and the liquid drop of the water droplets when the substrate is rotated is improved. Further, the vapor of alcohol dissolved in the water droplets raises the vapor pressure of the water droplets and evaporates the water droplets together with the alcohol content. As a result, the water droplets on the surface of the substrate W are efficiently and surely dried.

Particularly, in this embodiment, the gas spray nozzle 1
Since the spraying direction of the vapor by 3 is set to be the direction toward the rotation center of the surface of the substrate W, it is possible to perform more efficient drying on the rotation center portion where the water drainage is conventionally poor.

The following is the result of an experimental examination on how the drying efficiency was improved by this example. In the configuration of only the centrifugal dehydration shown as the conventional example, it took 30 seconds at the rotation speed of the substrate W of 3000 [rpm] to completely finish the drying. Further, in the configuration in which the nitrogen gas is sprayed to the centrifugal dehydration, the rotation speed of the substrate W is 3000 [rpm] and it takes 15 seconds. On the other hand, in the rotary substrate processing apparatus 1 of this embodiment, the rotation speed of the substrate W is 3000 [rpm].
] It took 5 seconds.

In this embodiment, as described above, the drying process and the actual spraying period of the IPA vapor are completely coincident with each other. On the other hand, as shown in FIG. The vapor spraying period may be finished before the end of the drying process. Further, as shown in FIG. 5, the spraying of the IPA vapor may be started before the completion of the water washing step, and the IPA vapor spraying period may be partially overlapped with the pure water rinsing period in the water washing step.

The second embodiment of the present invention will be described below. The rotary substrate processing apparatus (horizontal axis rotary substrate drying apparatus) of the second embodiment differs from the rotary substrate processing apparatus 1 of the first embodiment in the configuration of the substrate processing unit 10. In the substrate processing unit 10 of the first embodiment, one substrate W is spin chucked.
1, but the substrate processing unit of the second embodiment is configured to hold a plurality of substrates W. The gas supply unit for supplying the nitrogen gas containing IPA vapor to the substrate processing unit has the same configuration as the gas supply unit 30 of the first embodiment. The configuration of the substrate processing section 50 of the second embodiment will be described below with reference to FIG.

As shown in FIG. 6, the substrate processing section 50 includes a substantially cylindrical processing container 51, a horizontal shaft type rotor 53 rotatably provided in the processing container 51, and a detachable type on the rotor 53. Substrate holder 55 that is installed and holds a plurality of substrates W
A holder elevating part 57 which is provided at the lower part of the processing container 51 so as to elevate and lower the substrate holder 55, and a plurality of substrate holders 55 which are arranged parallel to the horizontal axis of the rotor 53 and are held by the substrate holder 55. A gas spray nozzle 59 for spraying nitrogen gas from above toward the substrate W is provided.

At the upper part of the peripheral wall of the processing container 51, the substrate entrance / exit 6
1, and an exhaust port 63 is formed in the lower part of the peripheral wall. The substrate inlet / outlet 61 is covered with an upper lid 67 provided with an inlet 65 for taking in outside air. A filter 69 is attached to the suction port 65.

The rotor 53 has a pair of rotating flanges 71 and 72 arranged so as to face each other with a space therebetween, and a plurality of connecting rods 73 that connect the rotating flanges 71 and 72 so as to be integrally rotatable. There is. A pair of rotary flanges 71, 72
A substrate holder 55 is installed between them. Further, the rotary flanges 71 and 72 are fixed with a rotary shaft 75 protruding outward, and the rotary shaft 75 is supported by bearings 77 and 78 arranged at both ends of the processing container 51. The rotary shaft 75 is rotated by a drive motor (not shown) arranged outside the processing container 51. Between the bearing 77 and the rotary flange 71 of the rotary shaft 75, a propeller 79 is attached to prevent particles generated in the rotary shaft 75 and the bearing 77 from flowing back into the processing container 51. A propeller 80 is mounted between the bearing 78 and the rotary flange 72. The air flow caused by the propellers 79 and 80 can flow outward.

The gas spray nozzle 59 is formed by forming a plurality of holes 59a in the lengthwise direction of a tube having a circular cross section. As described above, nitrogen gas is applied from above toward the plurality of substrates W held by the substrate holder 55. Spray gas. The nitrogen gas is nitrogen gas containing IPA vapor supplied from a gas supply unit (not shown) having the same configuration as the gas supply unit 30 of the first embodiment.

According to the horizontal axis type rotary substrate drying apparatus of the second embodiment configured as described above, the centrifugal force generated by the rotation of the substrate W and the surface of the substrate W are applied to the substrate as in the first embodiment. IP
By spraying nitrogen gas containing A vapor, water droplets on the surface of the substrate W can be blown off.
Since a part of the vapor of A is dissolved in the water droplets on the surface of the substrate W, the surface tension of the water droplets is lowered, and the liquid drop of the water droplets when the substrate is rotated is improved. Further, the vapor of alcohol dissolved in the water droplets raises the vapor pressure of the water droplets and evaporates the water droplets together with the alcohol content. As a result, the water droplets on the surface of the substrate W can be dried efficiently and surely. In particular, according to this second embodiment,
Since a plurality of substrates W can be dried at the same time, the drying efficiency is excellent.

The third embodiment of the present invention will be described below. The rotary substrate processing apparatus (vertical axis rotary substrate drying apparatus) of the third embodiment differs from the rotary substrate processing apparatus 1 of the first and second embodiments in the configuration of the substrate processing unit 10. . In the substrate processing unit 50 of the second embodiment, the rotation shaft 75 of the rotor 53 on which the substrate holder is installed is arranged in the horizontal direction, but in the third embodiment, the rotation shaft of the rotor is arranged in the vertical direction. It is a configuration. The configuration of the substrate processing section 100 of the third embodiment will be described below with reference to FIG.

As shown in FIG. 7, the substrate processing section 100 is
A substantially cylindrical processing container 101, a vertical axis type rotor 103 rotatably provided in the processing container 101, and a rotor 10.
3, substrate holders 105 and 106 that are detachably installed on the substrate 3 and hold a plurality of substrates W, and the cylindrical rotation shaft 1 of the rotor 103.
A gas spray nozzle 109 that is inserted into the inside of 07 and projects from the rotation shaft 107 and sprays nitrogen gas toward the plurality of substrates W held by the substrate holders 105 and 106 is provided.

A suction port 111 is provided at the upper part of the processing container 101.
However, an exhaust port 113 is formed on the peripheral wall. A filter 115 is attached to the suction port 111. The gas spray nozzle 109 has a plurality of holes 109a formed in the length direction of a tube having a circular cross section, and sprays nitrogen gas toward the plurality of substrates W held by the substrate holders 105 and 106 as described above. . The nitrogen gas is nitrogen gas containing IPA vapor supplied from a gas supply unit (not shown) having the same configuration as the gas supply unit 30 of the first embodiment.

According to the vertical axis type rotary substrate drying apparatus of the third embodiment having the above-described structure, the centrifugal force due to the rotation of the substrate W and the substrate W can be applied similarly to the first and second embodiments. By blowing nitrogen gas containing IPA vapor onto the surface, the water droplets on the surface of the substrate W can be blown off. Furthermore, since a part of the IPA vapor dissolves in the water droplets on the surface of the substrate W, the surface of the water droplets The tension is lowered, and the liquid drop of water drops is improved when the substrate is rotated. Further, the vapor of alcohol dissolved in the water droplets raises the vapor pressure of the water droplets and evaporates the water droplets together with the alcohol content. As a result, the water droplets on the surface of the substrate W can be dried efficiently and surely. Particularly, according to the third embodiment, a plurality of substrates W can be dried at the same time as in the second embodiment, and the drying efficiency is excellent.

In the first to third embodiments, the vapor contained in the nitrogen gas is IPA vapor, but it may be replaced with vapor of other water-soluble alcohol such as methanol or ethanol.

Although some embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments. For example, instead of the semiconductor substrate W as a substrate, a glass substrate for liquid crystal may be used.
The vapor of IPA may be sprayed onto the substrate W in place of the nitrogen gas by spraying the vapor onto the substrate W, and the vapor may be sprayed onto the substrate W as it is, which can be carried out in various modes without departing from the scope of the present invention. Of course.

[0036]

As described above, according to the substrate drying method and the substrate drying apparatus of the present invention, the substrate can be efficiently and reliably dried.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a rotary substrate processing apparatus 1 as a first embodiment to which the present invention is applied.

FIG. 2 is a main part perspective view showing a spin chuck 11 provided in a substrate processing section 10 of a rotary substrate processing apparatus 1 and a substrate W held by the spin chuck 11.

FIG. 3 is a timing chart showing a relationship between a process such as IPA vapor spraying performed in the rotary substrate processing apparatus 1 and the rotation speed of the substrate W.

FIG. 4 is a timing chart showing a first different aspect of the relationship between the processing and the rotation speed of the substrate W.

5 is a timing chart showing a second different aspect of the relationship between the processing and the rotation speed of the substrate W. FIG.

FIG. 6 is a schematic configuration diagram showing a substrate processing section 50 of a rotary substrate processing apparatus as a second embodiment.

FIG. 7 is a schematic configuration diagram showing a substrate processing section 100 of a rotary substrate processing apparatus as a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotation type | mold substrate processing apparatus 10 ... Substrate processing part 11 ... Spin chuck 13 ... Gas spray nozzle 15 ... Scattering prevention member 17 ... Processing container 19 ... Upper lid 21 ... Forced exhaust port 23 ... Drive motor 30 ... Gas supply part 31 ... Nitrogen Gas inlet 33 ... Pipeline 35 ... Tank 37 ... Heater 50 ... Substrate processing unit 51 ... Processing container 53 ... Rotor 55 ... Substrate holder 59 ... Gas spray nozzle 59a ... Hole 100 ... Substrate processing unit 101 ... Processing container 103 ... Rotor 105, 106 ... Substrate holder 109 ... Gas spray nozzle 109a ... Hole W ... Substrate

Claims (3)

[Claims] 1. A substrate drying method of rotating a substrate to drain water drops adhering to the surface of the substrate and drying the substrate, wherein a vapor of a water-soluble alcohol is sprayed onto the surface of the rotating substrate. 2. The substrate drying method according to claim 1, wherein the vapor spraying direction is a direction toward the center of rotation of the substrate surface. 3. The substrate drying apparatus used in the method of claim 1, wherein the substrate rotating means holds and rotates the substrate, the vapor generating means generates vapor of water-soluble alcohol, and the vapor generating part. A substrate drying apparatus, comprising: a supply unit configured to supply the vapor of the water-soluble alcohol generated in step 1 to the surface of the substrate held by the substrate rotating unit.