KR100626869B1 - System for cleaning semiconductor wafers - Google Patents

Abstract

A semiconductor wafer cleaning system is disclosed. The disclosed semiconductor wafer cleaning system includes: an internal bath in which a plurality of wafers are accommodated, and a shower device is provided to spray cleaning liquid onto the wafer to clean the wafer; An outer bath installed at an outer edge of the inner bath to circulate the cleaning liquid; A circulation pipe installed to circulate the cleaning liquid from the external bath to the internal bath; A circulation pump installed at one side of the circulation pipe and connected to the external bath to operate a cleaning liquid; A heater installed at the other side of the circulation pipe to raise to a desired temperature to activate the chemical during cleaning of the wafer; A filter installed at another side of the circulation pipe to filter the cleaning liquid circulating through the circulation pipe; It characterized in that it comprises a; washing liquid inlet tube is installed so that the cleaning liquid flows into the inner bath.

According to the present invention, by making the hydrophobic silicon wafer surface hydrophilic after hydrofluoric acid (HF) cleaning, it is possible to prevent resorption of particles due to static electricity during the next step of cleaning, thereby maximizing the cleaning efficiency. have.

Wafer, hydrofluoric acid, ozone water

Description

Semiconductor Wafer Cleaning System {SYSTEM FOR CLEANING SEMICONDUCTOR WAFERS}

1 is a schematic flowchart of a cleaning process using hydrofluoric acid according to the prior art.

2 is a view schematically showing a configuration of a semiconductor wafer cleaning system according to the present invention.

Figure 3 is a detailed view of the shower device of Figure 2;

Figure 4 is a schematic cross-sectional view shown by cutting along the line A-A in FIG.

FIG. 5 is a schematic cross-sectional view taken along line B-B in FIG. 3. FIG.

6 is a detailed view showing 'C' part of FIG. 3 in more detail.

7 is a schematic flowchart of a cleaning process using hydrofluoric acid to which a semiconductor wafer cleaning system according to the present invention is applied.

<Description of the symbols for the main parts of the drawings>

11. Internal Bath

12. External Bath

21. Circulation pump

22. Ozone Contactor

24. Heater

31. Circulation piping

32. External Bath Drain

33. Ozone gas input pipe

34. Cleaning liquid input pipe

45. Quick Clean Valve

50. Shredder

51. Wafer

53. Bottom shower head sprayer

54. Front and rear shower sprayer

55. Side shear spray

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer cleaning system, and more particularly, a series of processes of rinsing, rinsing, and rinsing a wafer in a cleaning process using hydrofluoric acid (HF) in one bath. And a semiconductor wafer cleaning system that has been improved to proceed.

In the semiconductor manufacturing process, chemical-mechanical polishing equipment, which combines chemical removal processing and mechanical removal processing in one processing method, is used to planarize the widened surface of the wafer as the wafer is large-sized. have. Such CMP equipment consists of a polisher and a cleaner.

In the polisher, the wafer surface having the step is brought into close contact with the polishing pad, and then a slurry containing abrasive and chemical is injected between the wafer and the polishing pad to planarize the surface of the wafer.

After polishing, the cleaner removes residues and particles on the surface of the wafer.

Thus, in the semiconductor manufacturing process, the washing | cleaning process which removes a residue, particle | grains, etc. is important.

BACKGROUND ART Conventional cleaning processes are related to a cleaning method for cleaning and rinsing to remove organic materials and metal ions in a semiconductor wafer process using hydrofluoric acid or hydrofluoric acid and ozone water, and the related arts have been developed.

In this cleaning method, as shown in FIG. 1, rinsing was performed first, followed by hydrofluoric acid washing (steps 110, 120), and rapid drying and rinsing were then performed (steps 130, 140).

However, the above-mentioned rinsing, hydrofluoric acid cleaning, rinsing and drying processes are performed separately in different baths 1, 2, 3, and 4, and the wafer surface has unstable hydrophobicity. When proceeding to the next process step, there is a possibility of particle resorption.

In addition, using conventional wet cleaning (especially wafers of 12 inches or more) has a disadvantage of using a considerable amount of device space due to the multi-stage cleaning.

The present invention has been made to solve the above problems, and after hydrofluoric acid cleaning to make the surface of the hydrophobic silicon wafer hydrophilic to prevent resorption of particles due to static electricity, and to simplify the device to minimize the equipment space occupied by the device It is an object of the present invention to provide a semiconductor wafer cleaning system.

The semiconductor wafer cleaning system according to the present invention for achieving the above object comprises: an inner bath having a shower device provided with a plurality of wafers, and a cleaning liquid is injected to the wafer to clean the wafer; An outer bath installed at an outer edge of the inner bath to circulate the cleaning liquid; A circulation pipe installed to circulate the cleaning liquid from the external bath to the internal bath; A circulation pump installed at one side of the circulation pipe and connected to the external bath to operate a cleaning liquid; A heater installed at the other side of the circulation pipe to raise to a desired temperature to activate the chemical during cleaning of the wafer; A filter installed at another side of the circulation pipe to filter the cleaning liquid circulating through the circulation pipe; It characterized in that it comprises a; washing liquid inlet tube is installed so that the cleaning liquid flows into the inner bath.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view showing the configuration of a semiconductor wafer cleaning system according to the present invention.

Referring to the drawings, in the semiconductor wafer cleaning system according to the present invention, a plurality of wafers 51 are accommodated, and ultra-pure water (De-Ionized (DI) water) or the wafer 51 is used to clean the wafers 51. An inner bath (11) provided with a shower device (50) provided with a cleaning solution of ozone water (DIO₃), an outer bath (12) installed at an outer edge of the inner bath (11), and circulating with the cleaning solution; The circulation pipe 31 is installed to circulate the cleaning liquid from the outer bath 12 to the inner bath 11, and is connected to the outer bath 12 at one side of the circulation pipe 31 so as to operate the cleaning liquid to circulate. It is comprised including the pump 21.

In addition, the semiconductor wafer cleaning system according to the present invention includes a heater 24 installed at the other side of the circulation pipe 31 to raise to a desired temperature for activating the chemical during cleaning of the wafer 51, and the circulation pipe. A filter 25 for filtering the cleaning liquid circulating in the circulation pipe 31 and installed on the other side of the 31, and a cleaning liquid input such that the cleaning liquid such as ultrapure water or ozone water flows into the internal bath 11. The tube 34 is provided.

In addition, one side of the circulation pipe 31 is provided with an external bath drain pipe 32 so as to be discharged via the external bath 12 when overflowed after the cleaning solution is filled in the internal bath 11.

And on one side of the circulation pipe 31 is installed an ozone water concentration reduction prevention device to prevent a decrease in the concentration of ozone water to maintain a constant concentration, this ozone water concentration reduction prevention device is an ozone gas inlet pipe (10) 33) and an ozone contactor 22 which is installed in the circulation pipe 31 to one side of the ozone gas input pipe 33 so that ozone water is formed by the injected ozone gas.

In addition, an auxiliary heater 26 is installed at one side of the inner bath 11. Therefore, the heating of the chemical may be supplied in the process of circulating the circulation pipe 31 in the operation of the heater 24 or the auxiliary heater 26 or in the internal bath 11, or simultaneously.

Then, one side of the inner bath 11 is provided with a quick cleaning (QDR, Quick Dump Rinse) valve 45 for urgently draining the chemical in the inner bath 11 after the wafer 51 is cleaned.

The shower device 50 is configured such that the cleaning liquid is injected from above, below, and left and right of the wafer 51.

Specifically, as shown in FIG. 3, the shower device 50 is provided with a plurality of jetting means at predetermined intervals on the front and rear surfaces of the wafer 51 to spray the cleaning liquid toward the wafer 51. Front and rear side shower injector 54, and a lower side shower injector 53, which are provided with a plurality of spraying means at predetermined intervals on the bottom surface of the wafer 51, and spray the cleaning liquid toward the wafer 51; A plurality of injection means are installed on the left and right sides of the wafer 51 at regular intervals, and the side shower injection device 55 sprays the cleaning liquid toward the wafer 51.

Although each of the plurality of injection means is not shown in detail in the drawing, it may be composed of injection holes or injection nozzles formed in each shower injection device (53, 54, 55) is not limited to a special injection means. However, in order to perform effective cleaning of the wafer 51, it is preferable to use a spray nozzle.

In addition, as shown in FIG. 4, the lower side shower injection device 53 is formed in a U-shape to be sprayed in three directions of the wafer 51. In addition, the front and rear side shower injection device 54 is formed in a □ -shape to be injected in the four directions of the wafer 51, as shown in FIG.

In addition, as shown in Figure 6, the spacing of the injection means of the shear injection device (53, 54, 55) is, for example, 8 inches is preferably provided at intervals of about 6.34mm.

On the other hand, reference numerals 41, 42, 43, 44, which are not described in FIG. 2, are provided at one side of each pipe as described below to show a valve for controlling the inflow and discharge of the cleaning liquid and the like, and FIGS. 3 to 6 Reference numeral 52 denotes a shower of ultrapure or ozone water.

And reference numeral 23 shows a damper (damper) installed in the circulation pipe (31).

Referring to the operation of the semiconductor wafer cleaning system according to the present invention having the configuration as described above is as follows.

Referring back to the drawings, the semiconductor wafer cleaning system according to the present invention includes an internal bath 11 to an external bath 12 and a circulation pump 21, a damper 23, a heater 24, a filter 25, and the like. The wafer 51 is cleaned while being circulated to the inner bath 11 again.

In addition, when the wafer is cleaned by the circulation as described above, the surface of the wafer 51 may be made hydrophilic, thereby preventing resorption of particles during the movement after cleaning.

This will be described in more detail.

First, when performing the rinse process, the valves 42 and 44 on the circulation pipe 31 are closed, and the valves 41 and 43 of the external bath drain pipe 32 and the cleaning liquid inlet pipe 34 are opened. The ultrapure water is supplied to the inner bath 11 through the cleaning liquid inlet pipe 34, and the overflowed ultrapure water is drained through the circulation pipe 31 and the external bath drain pipe 32 through the external bath 12.

After a series of rinsing steps, the hydrofluoric acid is supplied together with ozone water and rinsed while circulating. The ozone water serves to oxidize the surface of the wafer 51, and the hydrofluoric acid performs cleaning while acting as an etching.

In addition, after sufficient cleaning is performed, all the valves 41, 42, 43, 44 are closed, and the rapid cleaning valve 45 is opened to emergencyly drain the chemical in the internal bath 11. This drained chemical can be recovered and reused.

In addition, since the surface of the etched wafer 51 becomes hydrophobic and unstable, particles can be adsorbed due to static electricity or the like, so that moisture of the wafer 51 is removed or watermarks are prevented through the shower device 50. Ultrapure water is supplied to continue cleaning. Ultrapure water can be replaced with ozone water.

After the drainage is completed, the rapid cleaning valve 45 is closed and the valve 43 on the cleaning liquid inlet pipe 34 is opened to rinse the ultrapure water or the ozone water to the internal bath 11.

At this time, the ozone water is supplied to continue supplying until the inner bath 11 is filled. Those overflowed after the inner bath 11 is filled up are drained through the outer bath 12 and through the circulation pipe 31 and the outer bath drain pipe 32.

On the other hand, the advantage of rinsing with ozone water is that the surface of the wafer 51 is made hydrophilic to prevent adsorption of particles when the wafer 51 is exposed to the outside of the bath.

Using this method, a series of rinsing, cleaning and rinsing can be performed in one internal bath (bath 1) 11 as shown in FIG. 7 (steps 210, 220, 230) and the wafer 51 having been rinsed. ) Dry through a dryer (step 240). This drying takes place in another bath, bath 2.

In addition, in order to activate the chemicals in the cleaning process, it may be used by raising the temperature. At this time, the temperature is increased by using the heater 24. In some cases, the auxiliary heater 26 may be used together.

In addition, the supply of ozone water used together in the hydrofluoric acid cleaning is used through the following process.

As shown in FIG. 2, the ozone water concentration lowering prevention device used for hydrofluoric acid cleaning is provided to supply ozone gas through the ozone gas inlet tube 33 during the chemical circulation process, and to form ozone water through the ozone contactor 22. do. The ozone water concentration reduction prevention device is to prevent the lowering of the concentration of ozone water and to maintain a constant concentration by continuously replenishing ozone which is halved due to the characteristic of ozone water during the circulation process in chemical cleaning.

As shown in FIG. 3, the shower apparatus 50 rinses the cleaning liquid evenly over the entire wafer 51 to prevent rinsing and to expose the surface of the hydrophobized surface by hydrofluoric acid cleaning.

4 and 5, the front and rear surfaces, the bottom surface, and the side cleaning liquid injectors are provided to be sprayed over the wafer 51 on both sides, the bottom, and the side surfaces thereof. And the interval between the injection hole of the shower device 50 or the injection means of the injection nozzle is ejected at a distance of 6.34mm, which is the distance between the wafer 51 in the cassette in the case of a general 8 inches. The distance between the wafers 51 in the cassette may vary according to the size of the wafer 51, and the distance may be changed accordingly.

As described above, the semiconductor wafer cleaning system according to the present invention has the following effects.

Conventionally, the surface becomes hydrophobic due to hydrofluoric acid cleaning, and the wafer surface becomes unstable, and there is a problem of resorption and contamination of particles due to static electricity during or out of the bath.

However, in the present invention, since a series of cleaning processes are performed in one bath, the hydrophobic silicon wafer surface is made hydrophilic after hydrofluoric acid (HF) cleaning, thereby resorbing particles due to static electricity during the next step of cleaning. The space of the apparatus can be greatly reduced by performing rinsing and cleaning in one bath as described above.

In particular, for large area wafers larger than 12 inches, the space taken up by the device can be significantly reduced.

In addition, a cleaning liquid injector capable of uniformly injecting the cleaning liquid over the entire wafer direction is provided so that the wafer is exposed to the air to block water marks that may occur during the drying process.

And since the surface of the wafer can be made hydrophilic, it is possible to prevent particles from resorbing on the wafer surface. Therefore, the cleaning efficiency can be maximized.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (13)

An internal bath in which a plurality of wafers are stored, and a shower device is provided to spray the cleaning liquid onto the wafer to clean the wafers; An outer bath installed at an outer edge of the inner bath to circulate the cleaning liquid; A circulation pipe installed to circulate the cleaning liquid from the external bath to the internal bath; A circulation pump installed at one side of the circulation pipe and connected to the external bath to operate a cleaning liquid; A heater installed at the other side of the circulation pipe to raise to a desired temperature to activate the chemical during cleaning of the wafer; A filter installed at another side of the circulation pipe to filter the cleaning liquid circulating through the circulation pipe; And a cleaning solution inlet tube installed so that the cleaning solution flows into the inner bath. The method of claim 1, One side of the circulation pipe is a semiconductor wafer cleaning system, characterized in that the external bath drain pipe is installed to be discharged via the external bath when the cleaning solution is filled in the inner bath and overflows. The method of claim 2, One side of the external bath drain pipe is a semiconductor wafer cleaning system, characterized in that a valve for controlling the external bath drain pipe is installed. The method of claim 1, One side of the circulation pipe is a semiconductor wafer cleaning system, characterized in that the ozone water concentration lowering prevention device is installed to prevent a decrease in the concentration of ozone water to maintain a constant concentration. The method of claim 4, wherein The ozone water concentration reduction prevention device, An ozone gas input pipe installed at one side of the circulation pipe to allow ozone gas to be introduced; And an ozone contactor installed at one side of the ozone gas inlet pipe so that ozone water is formed from the ozone gas introduced into the circulation pipe. The method of claim 1, One side of the inner bath is a semiconductor wafer cleaning system, characterized in that the auxiliary heater is installed. The method of claim 1, One side of the inner bath is a semiconductor wafer cleaning system, characterized in that the rapid cleaning valve for emergency draining the chemical in the inner bath after the cleaning of the wafer is installed. The method of claim 1, The shower device is a semiconductor wafer cleaning system, characterized in that the cleaning liquid is provided so as to spray the upper and lower sides and the left and right of the wafer. The method of claim 8, The shower device, Front and rear shower injectors provided with a plurality of spray means at predetermined intervals on the front and rear surfaces of the wafer to spray the cleaning liquid toward the wafer; A bottom shower injection device in which a plurality of injection means are installed at a predetermined interval on the bottom surface of the wafer to inject a cleaning liquid toward the wafer; And a side shower injector disposed at left and right sides of the wafer at predetermined intervals to inject a cleaning liquid toward the wafer. The method of claim 9, The bottom shower shower device, The semiconductor wafer cleaning system, characterized in that it is made of a U-shape to be injected in three directions of the wafer. The method of claim 9, The front and rear side shower injection device, The semiconductor wafer cleaning system, characterized in that the shape of the □ to be injected in the four directions of the wafer. The method of claim 9, And the jetting means comprises a jetting nozzle. The method of claim 1, One side of the circulation pipe and the cleaning liquid inlet pipe is a semiconductor wafer cleaning system, characterized in that a valve for controlling the inflow and discharge of the cleaning liquid and the like.

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