JPH04251929A - Vapor cleaning and drying apparatus - Google Patents

Abstract

PURPOSE:To provide a vapor cleaning and drying apparatus which ensures high application efficiency of solvent without using quartz which is expensive and easily damaged as a material of a cleaning vessel. CONSTITUTION:A title apparatus comprises a shutter 9 which opens only when a cleaning object is loaded and unloaded, a cooling coil 11 for condensing vapor of solvent, a cleaning object supporting board 13, a nozzle 12 for poring solvent to the cleaning object 14, an exhaust pipe 15 for collecting solvent and a cleaning vessel 10 having a gas supply pipe 16 for the purging and moreover includes an apparatus for high purity solvent of the predetermined temperature.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam cleaning/drying device that has good solvent utilization efficiency and is inexpensive to manufacture.

0002

2. Description of the Related Art Steam cleaning and drying equipment used in the manufacturing process of semiconductor devices is equipped with an ultrapure water rinsing tank as a preceding stage equipment, and the low-temperature cleaning material taken out from the rinsing tank is
The solvent is poured into boiling point temperature solvent vapor that has been evaporated from the heated solvent, and the solvent that condenses on the surface of the steam-cleaned object dissolves the water on the surface of the cleaning object and flows down, removing moisture. Almost pure solvent condensate covers the cleaning item;
The solvent condensate evaporates and the drying ends.

[0003] In order for the above process to work, the surface temperature of the object to be cleaned must be lower than the steam temperature.

On the other hand, the temperature of the object to be washed gradually rises due to the heat of condensation, and eventually reaches the steam temperature and the condensation action stops. During this time, the amount of solvent liquid condensed on the surface of the cleaning object is given by the following equation.

[0005]

[Math 1]

v...Condensed liquid amount H...Heat capacity of the cleaning material Tv...Steam temperature
To...Initial temperature of the cleaning material ρ...Density of the solvent
h... Heat of condensation of solvent The amount of condensed liquid is proportional to the heat capacity of the object to be cleaned.For example, if the object is 150 mm in diameter and 0.
A 7 mm silicon wafer was soaked in isopropyl alcohol (I
When performing steam cleaning drying using PA), To=2
At 0°C, v≒2.5cm3. Since v is the sum of both the front and back sides of the silicon wafer, the amount of solvent flowing to the front side is only 1.25 cm3.

[0007] Steam cleaning and drying is performed at a constant takt time (for example, 7 min). In the above example, the cleaning items are carried into the cleaning tank every 7 minutes, but steam generation continues even in the standby state. Evaporation rate is 100cm3/m
In, and the number of wafers processed at one time is 25, the utilization rate of the generated steam is as follows.

[0008]

[Math 2]

All of the remaining residue is condensed and recovered by the cooling coil, but since it contains water that is suspected of being contaminated, it cannot be reused unless it is cleaned.

[0010] Then, add 100 cm3 of high-purity fresh solvent.
It will continue to be replenished at /min. If the annual operating time is 3600 hours, the amount of solvent used is 3600 x 60 x
0.1=21600kg=21.6Ton, of which the amount flowing on the surface of the wafer is as follows.

21600×0.089=1922kg=1.
The 92Ton ULSI manufacturing process has very strict requirements regarding the purity of the solvent. Therefore, the material forming the cleaning tank should be
Recently, high-purity quartz has come to be used.

0012

[Problems to be Solved by the Invention] In the conventional technology using a quartz tank with a complicated shape as described above, the equipment is expensive and
Moreover, it had the serious drawback of being easily broken. Further, the conventional technology has a problem in that the efficiency of using the solvent is low.

An object of the present invention is to provide a steam cleaning/drying device that does not require the use of an expensive and easily damaged quartz cleaning tank, and which has good solvent utilization efficiency.

[0014]

[Means for Solving the Problems] The above object is achieved by providing a shutter that opens only when cleaning items are taken out or put in, a cooling coil installed on the inner wall to condense solvent vapor, and a cooling coil installed at the bottom to place the cleaning items. a support stand, a nozzle for pouring the solvent over the entire surface of the object to be cleaned, a drain pipe installed at the bottom to collect the solvent, and a tank for purging the inside of the tank with inert gas or clean dry air. This is achieved by providing a cleaning tank with a gas supply pipe and a device for supplying a high purity solvent at a predetermined temperature.

[0015]

[Operation] The steam cleaning drying apparatus of the present invention is equipped with a device for supplying a high-purity solvent at a predetermined temperature, and the liquid high-purity solvent adjusted to a temperature slightly lower than the boiling point of the solvent by the device is
It is poured directly from the nozzle of the cleaning tank onto the object to be cleaned, wetting the surface of the object and cleaning it. The heated solvent evaporates from the washed object when pouring of the solvent is stopped, and the object is dry when taken out from the washing tank. Note that the solvent that wets the cleaning items falls to the bottom of the cleaning tank,
This contaminated solvent is discharged to the outside of the cleaning tank from a drain pipe provided at the bottom of the cleaning tank. Therefore, the solvent introduced from the nozzle is poured directly onto the object to be cleaned, and the clean solvent does not come into direct contact with the cleaning tank, so it is necessary to use quartz, which is expensive and easily damaged, as the material for the cleaning tank. There is no. Furthermore, since the solvent introduced from the nozzle is poured directly onto the object to be washed as described above, the efficiency of use of the solvent is extremely high.

[0016]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the above-mentioned washing and drying apparatus according to the present invention. As shown in FIG. 1, the steam cleaning and drying apparatus of the present invention consists of a cleaning section (2), a solvent heating section (2), and a solvent delivery section (2). These are essential elements for heating high-purity solvents to a predetermined temperature.
It is only necessary to have the ability to supply the above-mentioned cleaning section (3) when necessary.

[0017] The solvent delivery section (■) is a canister
This device pressurizes the solvent 2 in the tank with N2 gas fed through a filter 3 and pushes it out through a control valve 4 and a filter 5. The solvent heating section (2) houses a heat exchange coil 7 in a water tank 6 whose water temperature is controlled to be constant, and heats the solvent sent from the solvent delivery section (2) to a predetermined temperature. 8 in the figure indicates a heater. If the internal volume of the heat exchange coil 7 is made slightly larger than the amount of solvent used in one cleaning bath, it is easy to raise the temperature of the solvent even during the standby time.

The cleaning section (2) consists of a cleaning tank 10 provided with a shutter 9 at the opening and a support table 13 on the bottom on which the object 14 to be washed is placed, and a tank for supplying a solvent in the upper part of the cleaning tank 10. A nozzle 12 is provided, and a cooling coil 11 is attached to the inner wall of the tank for cooling and condensing the solvent vapor diffused within the tank. Furthermore, a gas supply pipe 16 is provided at the bottom of the tank 10 for purging the inside of the tank with an inert gas or clean dry air, and a drain pipe 15 is installed at the bottom for discharging contaminated solvent that has fallen to the outside of the tank. We are preparing for

When the object to be washed 14 is placed on the object support stand 13 of the washing tank 10 and the shutter 9 at the opening is closed, the heat exchange coil 7 of the solvent heating section (2) heats the object to a temperature slightly higher than the boiling point of the solvent. The high purity solvent heated to a low temperature flows through the nozzle 12.
It is sent from the washing material 14 and poured into the washing material 14.
Water is removed by dissolving and washing away water that may be contaminated from the surface of the surface. Therefore, in the final process of cleaning, the cleaning object 14
is covered with almost pure solvent, and since the solvent is heated, it evaporates quickly, and a dry washed product 14 is obtained. On the other hand, the contaminated solvent that has fallen to the bottom of the cleaning tank 10 is discharged from the cleaning tank 10 through a drain pipe 15 provided at the bottom. As mentioned above, since the warmed clean solvent introduced from the nozzle 12 is poured directly onto the cleaning object 14, the clean solvent does not come into direct contact with the cleaning tank 10, and therefore, as a cleaning tank, Since there is no problem even if the metal ions of the constituent materials are eluted, there is no need to use quartz, which is expensive and easily damaged, and stainless steel can be used sufficiently. Furthermore, since the solvent supply system is always in contact with only high-purity solvent, there is no risk that the surface that comes into contact with the solvent solution will be contaminated, so fluororesin or the like can be used.

[0020] In the present invention, the solvent is poured directly onto the object to be cleaned, so the solvent utilization efficiency is high.In the conventional method of cleaning by contacting with solvent vapor diffused in a tank, the solvent utilization efficiency is 8 to 8. However, in the present invention, although it varies depending on how the cleaning items are arranged in the cleaning tank, it is usually 3%.
Solvent utilization efficiencies of 0-50% can be obtained.

Although only one nozzle 12 for injecting the solvent is shown in FIG. 1, a plurality of nozzles may be used in order to effectively wet the entire surface of the object 14 with the solvent. In addition, the nozzle can be used as a movable nozzle, and when the object to be washed is put in or taken out from the washing tank, it can be pulled into the wall side of the tank, and after the object to be washed is placed on a support stand, the movable nozzle can be moved directly above the object to be washed. It may be moved so that the solvent can be poured effectively.

[0022]

[Effects of the Invention] As described above, the steam cleaning/drying apparatus according to the present invention has a shutter that opens only when cleaning items are taken in and out, a cooling coil provided on the inner wall for condensing solvent vapor, and a cooling coil for mounting cleaning items. A support stand installed at the bottom of the tank, a nozzle for pouring the solvent over the entire surface of the cleaning object, a drain pipe installed at the bottom for recovering the solvent, and an inert gas or clean dry air inside the tank. By having a cleaning tank with a gas supply pipe for purging with water and a device for supplying high-purity solvent at a predetermined temperature, it is possible to use inexpensive metal materials instead of using expensive and easily damaged materials such as quartz. It is possible to obtain a steam cleaning/drying device that can form a cleaning tank and has high solvent utilization efficiency.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a steam cleaning drying apparatus according to the present invention.

[Explanation of symbols]

7 Heat exchange coil 9 Shutter 11 Cooling coil 12 Nozzle 13 Support stand 14 Washing items 15 Drain pipe 16 Gas supply pipe

Claims (2)

[Claims] Claims 1: A shutter that opens only when taking in and out the cleaning items; a cooling coil provided on the inner wall for condensing solvent vapor; a support stand provided at the bottom for mounting the cleaning items; and the cleaning items. A cleaning device that has a nozzle for pouring solvent over the entire surface of the tank, a drain pipe provided at the bottom to collect the solvent, and a gas supply pipe for purging the inside of the tank with inert gas or clean dry air. A steam cleaning/drying device equipped with a tank and a device for supplying high-purity solvent at a predetermined temperature. 2. The steam cleaning and drying apparatus according to claim 1, wherein the high purity solvent at the predetermined temperature is a high purity solvent slightly lower than the boiling point temperature of the solvent.