JPH09162154A - Substrate treating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the steam cleaning/drying performance by enhancing the circulation efficiency of phase conversion, i.e., boiling, evaporation and condensation, of a cleaning solvent. SOLUTION: A container 2 is provided, on the upper surface thereof, with an opening/closing cover body 3 equipped with a heater 6, at the lower part of bottom face and on the outer circumferential part of side face 21 thereof, with heaters 4, 5 and, at the upper part of inner side face thereof, with a cooling pipe 81 and a pressure reduction port P2. The pressure reduction port P2 is coupled with a pressure reducing section 9 and a solvent Q, contained in the enclosed container 2, is heated by means of the heater 4 under reduced pressure and boiled. On the other hand, it is cooled by means of a cooling pipe 81 and the vapor of solvent convects in a cleaning/drying chamber. The side face 21 of container and the cover body 3 are heated by means of the heaters 5, 6 and condensation of vapor is prevented thereat thus realizing ideal convection of vapor. A wafer 15 is exposed to the convection of vapor and the solvent is condensed on the surface thereof. The wafer 15 is cleaned with the condensed droplet and dried with latent heat generated at the time of condensation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for cleaning and drying a substrate such as a semiconductor wafer by using a solvent vapor.

[0002]

2. Description of the Related Art FIG. 6 is a schematic diagram showing the structure of a conventional steam dryer. A vapor drying apparatus 100 shown in the figure includes a container 101 that constitutes a drying chamber, a liquid organic solvent 102 such as trichlene, isopropyl alcohol (IPA), etc. housed in the container 101, and the organic solvent 1.
A heater 103 for vaporizing 02 and a cooling pipe 104 for liquefying the vapor of the organic solvent 102 are provided. The cooling pipe 104 is disposed above the inner side surface of the container 101, and cools the vapor of the organic solvent 102 that has risen to liquefy it in a mist state and lower it.

In the vapor drying apparatus 100, a wafer 105 is vertically oriented (in a direction in which a wafer peripheral edge is in a substantially vertical plane) in a substantially center of a container 101, and a heater 103 heats the organic solvent 102 to a boiling point or more under normal pressure. Washing and drying are performed by heating.

That is, when the liquid organic solvent 102 is boiled and converted into vapor, and the vapor rises, a part of the vapor is condensed on the surface of the wafer 105. The condensed droplets of the organic solvent 102 flow along the surface of the wafer 105, whereby the surface of the wafer 105 is cleaned. In addition, organic solvent 1
Latent heat due to the aggregation of 02 is applied to the wafer 105, whereby the wafer 105 is heated and dried. The droplets of the organic solvent 104 flowing down on the surface of the wafer 105 drop to the bottom of the container 101, and the liquid organic solvent 102 is discharged.
Is reduced to

On the other hand, the vapor of the organic solvent 102 that has not aggregated on the surface of the wafer 105 rises above the wafer 105 and is cooled by the cooling pipe 104 to become a mist-like liquid, part of which becomes a descending air stream. While the other part of the container 101 descends, the rest is condensed on the inner surface of the container 101, flows down on the inner surface, and is returned to the organic solvent 102 at the bottom of the container.

As described above, the organic solvent 1 is replenished in the container 101 by convection of vapor of the organic solvent 102 and heating.
No. 02 vapor ascending air current is generated, and the wafer 1
Of the organic solvent 102 aggregated on the surface of the wafer 105 by exposing the wafer 05 and heating by latent heat.
The cleaning and drying of 05 are performed simultaneously.

Further, Japanese Patent Laid-Open No. 63-10528 discloses a vapor drying method in which an organic solvent is vaporized by low temperature boiling under reduced pressure. In this drying method, the organic solvent is vaporized by boiling at a low temperature to suppress unnecessary vapor generation and reduce the risk of explosion of the organic solvent.

[0008]

The conventional vapor drying apparatus described above promotes cleaning and drying by heating and boiling the solvent 102 and exposing the wafer 105 to the circulation of the phase conversion of evaporation and aggregation of the solvent 102. However, since the organic solvent 102 is vaporized under normal pressure, only the organic solvent having a relatively low boiling point such as trichlene is substantially used in consideration of the circulation efficiency of the phase conversion of the solvent 102. .

However, since the above organic solvent is highly flammable and extremely dangerous, it is preferable to use pure water which is less dangerous. Although it is possible to use pure water as a solvent in the conventional apparatus, it is difficult to efficiently circulate the phase conversion despite the high boiling point of pure water and the large heating energy. Was difficult to apply to.

On the other hand, the drying method disclosed in Japanese Patent Laid-Open No. 63-10528 is intended to facilitate the removal of water droplets by forming a film of an organic substance on the surface of the wafer to which the water droplets are attached. Wafer cleaning and drying are not performed simultaneously using conversion. Therefore, in the same publication, it is shown that the organic solvent is vaporized by low-pressure boiling, but simply by low-pressure boiling the organic solvent, it is possible to efficiently perform the circulation of the phase conversion of evaporation and aggregation of the solvent. It is difficult, and it is extremely difficult to simultaneously wash and dry the wafer by the drying method disclosed in the publication.

The present invention has been made in view of the above problems, and provides a substrate processing apparatus capable of enhancing the circulation efficiency of phase conversion of a solvent and effectively cleaning and drying a substrate. .

[0012]

According to the present invention, a substrate treatment is carried out in which vapor of a solvent is aggregated on a surface of a substrate, the substrate is washed by flowing droplets of the solvent, and latent heat of the aggregation is used to dry the substrate. An apparatus comprising: a closed container in which the liquid solvent and the substrate are housed; a decompression means for reducing the pressure in the closed container; and a liquid medium for heating the solvent to evaporate the solvent. And heating means for cooling the vapor of the solvent, which is provided at a position above the storage position of the substrate on the side surface of the closed container (claim 1).

According to the above construction, the substrate is cleaned by heating the liquid medium by the first heating means while the pressure-reducing means brings the closed container containing the medium and the substrate into a predetermined decompressed state. And heating is performed. When the liquid medium is heated and the temperature of the solvent rises to the boiling point under reduced pressure, the solvent evaporates and the vapor rises. A part of the solvent vapor comes into contact with the surface of the substrate and is cooled by the substrate and aggregates. The aggregated droplets of the solvent flow down on the substrate surface and drop to the bottom surface of the container, but the substrate surface is washed by the downward flow of the solvent droplets. Further, the substrate is heated by the latent heat of the solvent vapor, which causes the substrate to be dried.

On the other hand, the vapor of the solvent not used for cleaning and drying the substrate rises above the storage position of the substrate, but is cooled by the cooling means to become a mist-like liquid.
It descends from the cooling position and is reduced to the liquid solvent on the bottom of the container. Then, when the substrate rises to the boiling point of the solvent under reduced pressure by the circulation of the phase conversion of the evaporation and aggregation of the solvent described above, the aggregation of the liquefied solvent on the substrate surface is stopped, and the cleaning and drying process is completed.

Further, according to the present invention, in the substrate processing apparatus, the ceiling surface of the closed container is inclined (claim 2).

With the above structure, the vapor of the solvent reaching the ceiling surface of the closed container is condensed on the ceiling surface, and the droplets drop by its own weight or flow down along the ceiling surface. Since it is inclined, the droplets of the solvent that have condensed on the ceiling surface flow down along the ceiling surface and are prevented from falling onto the substrate.

Further, according to the present invention, in the above substrate processing apparatus, there is provided a second heating means for heating a substantially central portion of a side surface of the closed container (claim 3). According to the above configuration, by heating the side surface of the container to a temperature equal to or higher than the boiling point of the solvent under reduced pressure by the second heating means, the solvent in the form of atomized liquid adheres to the substantially central part of the side surface of the container and The reduction from the side surface of the container to the bottom surface of the container is suppressed, and the vapor of the solvent efficiently convects inside the container.

Further, the present invention provides the substrate processing apparatus, further comprising a third heating means for heating the ceiling portion of the closed container (claim 4). According to the above configuration, the third heating means heats the ceiling of the container to a temperature equal to or higher than the boiling point of the solvent under reduced pressure, thereby preventing vaporization of the solvent vapor that has risen to the ceiling on the ceiling surface.

In the present invention, pure water is used as the solvent (claim 5). By using pure water as the solvent, the flammability is eliminated and the risk is reduced.

[0020]

1 is a schematic view of a substrate processing apparatus according to the present invention. The substrate processing apparatus 1 shown in the figure has a cylindrical container 2 on the top of which a hemispherical lid 3 is openably and closably provided, heaters 4, 5, and 6, a power supply unit 7, a cooling unit 8, and a decompression unit 9. This is a batch-type steam cleaning / drying apparatus including a purging unit 10, a condenser 11, and a control unit 12.

The substrate processing apparatus 1 is adapted to vaporize the solvent by low pressure boiling so that the most suitable vapor cleaning and drying can be performed when using pure water as the solvent. As a result, it is possible to suitably circulate boiling, evaporation, and agglomeration without excessively vaporizing pure water, and as described later, it is possible to perform vapor cleaning and drying of the substrate safely and highly efficiently. ing. Although pure water is preferably used as the solvent from the viewpoint of safety and cleaning efficiency, it is also possible to use an organic solvent such as IPA.

The container 2 and the lid 3 constitute a cleaning / drying chamber, and are made of quartz, and an O-ring or the like is provided on the joint surface between the container 2 and the lid 3 so as to form a sealed cleaning / drying chamber. The seal mechanism of is provided. Also, the container 2 has a side surface 21.
Is provided with a supply port P1 for supplying a liquid solvent Q for cleaning to an appropriate place on the lower side, an exhaust port P2 is provided at an appropriate place on the upper side of the side surface 21 for exhausting the cleaning / drying chamber, and the cleaning / drying is performed substantially at the center of the bottom surface 22 A discharge port P3 for discharging the treated solvent Q is provided. Further, a pressure sensor 13 for detecting the indoor pressure is provided at an appropriate position in the washing / drying chamber.

On the other hand, the lid 3 has a semi-spherical shape curved outward, and a purge port P4 for adjusting the pressure in the washing / drying chamber is provided at substantially the center of the ceiling surface 31, and the purge section 10 is provided at this purge port P4. Are connected. Each port P1
Valves B1, B2, B3, and B4 for opening and closing ports are provided at the base ends of P4 to P4, respectively. The lid 3 is curved so as to prevent the droplets of the solvent Q condensed on the ceiling surface 31 from falling, and an appropriate angle may be provided from the approximate center to the outer peripheral direction. Good.

The heater 4 is the solvent Q charged in the container 2.
Is a heat source for heating and boiling the water vapor and is disposed below the bottom surface 22 of the container 2. The heater 5 is a heat source for heating the side surface 21 of the cleaning / drying chamber, and is a side surface 21 of the container 2.
The heating heater 6 is a heat source for heating the ceiling portion of the cleaning / drying chamber, and is provided on the outer peripheral portion of the ceiling surface 31 of the lid 3.

The heaters 4 to 6 are connected to the power source section 7,
Power is supplied from the power supply unit 7. The energization control of the power supply unit 7 is performed by the control unit 12.

The cooling unit 8 comprises a cooling pipe 81 and a refrigerant circulator 82 for circulating a cooling medium made of an organic solvent such as water or CFCs in the cooling pipe 81. The cooling pipe 81 is an inner peripheral surface of the upper side surface of the container 2. Are arranged along.

The cooling pipe 81 is provided above the container 2 in order to prevent the solvent Q, which has been heated and boiled by the heater 4 and vaporized, from rising and to generate a descending air flow. Solvent Q
Of the vapor rises to a position above the container 2, it is cooled by the cooling pipe 81 and condensed into liquid fine particles (fog) Q ', and the atomized solvent Q'falls by its own weight.

The depressurizing unit 9 has a vacuum pump such as a rotary pump, and the vacuum pump sucks air in the washing / drying chamber from the exhaust port P2 to reduce the pressure in the washing / drying chamber to a predetermined value. The decompression unit 9 is connected to the exhaust port P2 via the condenser 11. Capacitor 11
Is for separating water in the exhaust gas, and the separated water is discharged through the drain 111 provided on the bottom surface.

On the other hand, the purge unit 10 has a gas supply unit for supplying an inert gas such as helium, and supplies the inert gas into the cleaning / drying chamber whose pressure has been reduced from the purge port P4 so that the pressure inside the chamber becomes normal pressure. Up to.

A wafer accommodating portion 14 for accommodating a wafer 15, which is a material to be dried, is provided at a substantially central position in the container 2. For example, as shown in FIG. 2, the wafer storage unit 14 includes a plurality of pairs of holding grooves 1 on both long sides of a rectangular holding frame 141.
42 and 142 'are formed at a predetermined interval, and by inserting the peripheral edge of the wafer 15 into each holding groove pair 142, 142', a plurality of wafers 15 are vertically erected and held in an array. Has become.

It is sufficient that the front and back surfaces of the wafer 15 are inclined with respect to the horizontal plane, and the front and back surfaces do not necessarily need to be aligned in the vertical direction. Therefore, the holding grooves 142, 14
2 ′ may be inclined with respect to the longitudinal direction of the long side of the holding frame 141 so that the front and back surfaces of the wafer 15 are inclined with respect to the vertical direction.

The controller 12 centrally controls the cleaning / drying of the wafer 15 according to a preset cleaning / drying process. The control unit 12 controls the drive of each actuator such as the valves B1 to B4, the power supply unit 7, the cooling unit 8, the decompression unit 9, and the purge unit 10 to clean and dry the wafer 15.

Next, the cleaning / drying operation of the substrate processing apparatus will be described with reference to the flowchart of FIG.
First, the lid 3 is opened upward, the wafer 15 is set in the wafer storage portion 14 in the container 2, and then the lid 3 is closed (step S1). Subsequently, the valve B1 of the supply port P1 is opened to supply a predetermined amount of the liquid solvent Q into the container 2 from a solvent supply device (not shown), and then the valve B1 is closed (switch S2). Then, the valve B2 of the exhaust port P2 is opened, the vacuum pump of the decompression unit 9 is driven, and the pressure in the cleaning / drying chamber is reduced to a predetermined value (step S3).
Further, the power supply unit 7 is driven to supply power to the heaters 4, 5 and 6, and the bottom surface 22, the side surface 21 of the container 2 and the ceiling portion of the lid 3 are heated to a temperature equal to or higher than the boiling point T _Q of the solvent Q under reduced pressure. It is heated (step S4).

When the cleaning / drying chamber is decompressed and the heater 5 heats the bottom surface 22 of the container 2, the solvent Q is vaporized and its vapor rises. Since the side surface 21 of the container 2 is heated by the heater 5, the solvent Q vaporized at the bottom of the container 2 rises upward without aggregating at the side surface 21 and reaches the upper position of the container 2 and the cooling pipe 81 The carrier medium Q'is condensed as liquid particles in the form of mist by being cooled by. The atomized solvent Q ′ descends to form a descending air stream, but since it is heated at room temperature during the descending and converted into vapor, it rises again before reaching the bottom of the container 2 and is vaporized. Due to the solvent Q and the liquefied solvent Q ′, convection of the solvents Q and Q ′ occurs in the washing / drying chamber. Since the heat of vaporization taken away from the liquid solvent Q by evaporation is replenished by the heater 4, the liquid solvent Q vaporizes smoothly until the room temperature rises to the boiling point T _Q of the solvent Q under reduced pressure. Be seen.

Then, in the convection generation process of the solvents Q and Q ', a part of the vapor of the solvent Q is condensed on the surface of the wafer 15, and the droplets flow down the surface of the wafer 15 to clean the wafer 15. Further, latent heat due to the agglomeration of the solvent Q is applied to the wafer 15, whereby the wafer 15 is heated and simultaneously dried (step 5).

Although a part of the vapor of the solvent Q rises up to the curved ceiling surface 31 of the lid body 3, since the lid body 3 is heated, the solvent Q is condensed on the ceiling surface 31 of the lid body 3. The droplets do not drop on the wafer 15.

Subsequently, it is judged whether or not a predetermined cleaning and drying time set in advance has elapsed (step 6). If the cleaning and drying time has elapsed, it is determined that the cleaning and drying processing has ended, and the process proceeds to step 7. To do. The above washing and drying time is
This is the time for the temperature of the wafer 15 heated by latent heat to rise to the boiling point T _Q of the solvent Q under reduced pressure. Wafer 15
Is raised to this temperature, the agglomeration of the solvent Q on the wafer 15 does not occur, so that the practical cleaning and drying process of the wafer 15 is completed at this point.

When the process proceeds to step 7, the purge port P
The valve B4 of No. 2 is opened, the inert gas is supplied from the purging unit 10 to the cleaning / drying chamber, and the pressure in the chamber is returned to normal pressure. Subsequently, the lid 3 is opened, the wafer 15 is taken out (step 8), and the valve B2 of the discharge port P2 is further opened.
The solvent Q in the container 2 is discharged (step 9), and the washing / drying process is completed.

In the above embodiment, the supply port P2 and the discharge port P3 of the container 2 are provided separately, but
As shown in FIG. 4, the common port P5 may be used, and the supply passage may be branched in the middle of the discharge passage. If the supply / exhaust port is set to the common port P5 in this manner, for example, after the cleaning with the cleaning chemical solution is completed, pure water is supplied from the common port P5 to cause the cleaning chemical solution in the container 2 to overflow from the upper surface of the container 2 It is possible to continuously perform cleaning with the cleaning chemical solution and pure water without exposing 15 to the outside air. Therefore, it is possible to continuously perform a series of conventional washing and drying steps using the washing / drying apparatus according to the present invention.

Further, as shown in FIG. 5, the ultrasonic oscillator 1
If 6 can be supported on the upper surface of the container 2, an ultrasonic cleaning process, which is performed as necessary in the cleaning process, can be performed by the same cleaning / drying device. In this case, if the ultrasonic wave oscillator 16 is brought into contact with the surface of the liquid while supplying the solvent Q so as to provide an overflow state and the ultrasonic energy is directly supplied to the solvent Q, ultrasonic cleaning may be performed as necessary. It can be done easily.

[0041]

As described above, in a substrate processing apparatus in which solvent vapor is agglomerated on the surface of a substrate, the substrate is washed by the droplets of the solvent flowing down, and the substrate is dried by latent heat due to the agglomeration. While heating the solvent under
Since it is vaporized by boiling at a low temperature, a solvent having a relatively high boiling point can be effectively and safely used for vapor cleaning and drying of the substrate. Further, since the low pressure boiling is performed, the heating energy for replenishing the steam can be reduced.

Further, since the ceiling surface of the closed container is inclined, it is possible to prevent the droplets of the solvent condensed on the ceiling surface from dropping onto the substrate.

Further, since the substantially central portion of the side surface of the closed vessel is heated, the vapor of the solvent does not aggregate on the inner surface of the vessel, and the convection of the vapor of the solvent can be effectively generated.

Further, since the ceiling surface of the closed container is heated, the condensation of the solvent vapor on the ceiling surface of the closed container is prevented, and the droplets of the solvent are prevented from dropping onto the substrate.
Further, since pure water is used as the solvent, safe and highly accurate cleaning and drying can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a substrate processing apparatus according to the present invention.

FIG. 2 is a perspective view showing the structure of a wafer storage unit.

FIG. 3 is a flowchart showing a cleaning / drying operation of the substrate processing apparatus according to the present invention.

FIG. 4 is a diagram showing a second embodiment of a cleaning / drying container applied to the substrate processing apparatus according to the present invention.

FIG. 5 is a diagram showing a method of ultrasonic cleaning using the substrate processing apparatus according to the present invention.

FIG. 6 is a schematic configuration diagram showing a configuration of a conventional steam drying device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 2 Container 21 Side surface 22 Bottom surface 3 Lid body 31 Ceiling surface 4, 5, 6 Heating heater 7 Power supply section 8 Cooling section 81 Cooling pipe 82 Refrigerant circulator 9 Pressure reducing section 10 Purging section 11 Condenser 12 Control section 13 Pressure sensor 14 Wafer Storage Section 141 Holding Frame 142, 142 'Holding Groove 15 Wafer 16 Ultrasonic Oscillator Q Solvent

Claims (5)

[Claims] 1. A solvent vapor is condensed on the surface of a substrate, and the substrate is washed by the flow of droplets of the solvent.
A substrate processing apparatus for drying the substrate by imparting latent heat due to agglomeration, in which a closed container in which the solvent of the liquid and the substrate are stored, a decompression means for reducing the pressure in the closed container, and a liquid A first heating means for heating the solvent to evaporate the solvent; and a cooling means for cooling the vapor of the solvent, the cooling means being provided at a position higher than the storage position of the substrate on the side surface of the closed container. A substrate processing apparatus comprising: 2. The substrate processing apparatus according to claim 1, wherein
A substrate processing apparatus, wherein a ceiling surface of the closed container is inclined. 3. The substrate processing apparatus according to claim 1, further comprising a second heating unit that heats a substantially central portion of a side surface of the closed container. 4. The substrate processing apparatus according to claim 1, wherein the ceiling part of the closed container is heated.
A substrate processing apparatus, comprising: 5. The substrate processing apparatus according to claim 1, wherein the solvent is pure water.