KR20040082170A - very precise cleaning apparatus using supercritical fluid with an improved structure - Google Patents

Abstract

PURPOSE: A superprecision cleaning apparatus using supercritical fluid having an improved structure is provided to perform uniformly and efficiently a cleaning process by improving a spraying structure and a structure of a sustain plate. CONSTITUTION: A cleaning fluid supply unit(10) stores and supplies one or more kinds of cleaning fluid. A heat exchanger(20) is used for mixing or cooling the one or more kinds of cleaning fluid. A high-pressure pump(30) is used for pressing the cleaning fluid to form the supercritical fluid. A reaction unit(40) cleans a target by using the supercritical fluid of the high-pressure pump. A processing unit processes the cleaning fluid of the reaction unit. The reaction unit includes a sustain plate for loading the target, a driver for rotating the sustain plate, and a sprayer for spraying the supercritical fluid.

Description

Very precise cleaning apparatus using supercritical fluid with an improved structure

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environmentally friendly dry cleaning apparatus that removes fine contaminants remaining on a surface of a target object by using a supercritical fluid. As a further improved structure, the present invention relates to an ultra-precision cleaning device configured to be removed more precisely.

In general, cleaning is classified into wet cleaning and dry cleaning, and among these, the most widely used cleaning method in the semiconductor process is wet cleaning.

Wet cleaning is a method of continuously removing contaminants by using chemicals suitable for contaminants in each cleaning step. SPM (H ₂ SO ₄ : H ₂ O ₂ ), APM (NH ₄ OH: H ₂ O ₂ Remove contaminants remaining in the object to clean by using a large amount of acid and alkaline solution such as: H ₂ O), HPM (HCl: H ₂ O ₂ ), HF, DHF.

However, such wet cleaning has a problem of acting as a factor of raising the product cost by using a large amount of ultrapure water and chemicals, as well as causing environmental pollution due to wastewater discharged after cleaning.

In response to this, a precision cleaning device has been developed, which is configured to introduce supercritical fluid compressed by a high pressure pump into the reactor and to perform precise cleaning in an environmentally friendly manner.

Such a conventional cleaning apparatus is used to clean precise parts such as high integrated circuits, but there are still limitations in removing contaminants of microstructures strongly adhered to high integrated circuits by interfacial tension.

On the other hand, the present inventors have developed a cleaning device having a higher cleaning efficiency than the conventional cleaning device using a supercritical fluid in the cleaning process according to the semiconductor process.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional cleaning device, and an object of the present invention is to provide an improved type of ultra-precision cleaning device, which is very suitable for removing contaminants of a microstructure strongly adhered to a highly integrated circuit due to interfacial tension. It is done.

In this aspect, a specific object of the present invention is to maintain the to-be-cleaned object so that the supercritical fluid is sprayed in the reactor, and the sprayed supercritical fluid can be cleaned uniformly. It is to provide an improved type of ultra-precision cleaning device provided with a holding plate rotatable inside the reactor.

1 is a circuit diagram showing an overall high precision cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a heat exchanger of FIG.

3 is an exploded perspective view showing a reactor of the cleaning apparatus of FIG. 1, with a driving part, a sensor, a pressure gauge, and the like removed.

4A and 4B are cross-sectional views illustrating the reactor in a state before sealing and in a sealing state, respectively.

In order to achieve the above object, the ultra-precision cleaning apparatus 1 according to the present invention includes a cleaning fluid supply unit 10 for storing and supplying at least one cleaning fluid; A heat exchanger (20) for mixing and cooling the cleaning fluid flowing from the cleaning fluid supply unit (10); A high pressure pump 30 for pressurizing the cleaning fluid from the heat exchanger 20 in a supercritical state; A reactor 40 for cleaning the object to be cleaned using the supercritical fluid from the high pressure pump 30; Means for treating the cleaning fluid used in the reactor 40, the reactor 40, the holding plate 43, the object to be cleaned is placed and held so that the object to be cleaned is uniformly cleaned as a whole And a driving unit 5 for rotating the holding plate 43 and a spraying unit 48 for spraying the supercritical fluid to the object to be cleaned held by the holding plate 43. Do it.

In this case, the to-be-cleaned object maintained in the holding plate 43 in the reactor 40 is preferably a circular wafer, and the spray unit 48 for spraying supercritical fluid to the to-be-cleaned object is constant. It is preferable that it is a ring spray part which has the surface of many spray holes 48a formed in the space | interval.

In addition, the ring-shaped spraying unit 48 is preferably installed in a form surrounding the circumference of the holding plate 43 in the inner side of the reactor 40.

In addition, the reactor 40 includes a frame 42 having a concave cleaning space 42a at the bottom of which the cleaning is performed, and a holding rotatably installed by the drive unit 5 inside the cleaning space 42a. Sealing 44 disposed on the plate 43 and the sealing sheet 42b of the frame 42 at the outer circumference of the upper end of the cleaning space 42a and arranged around the wafer holding plate 43. ) And a sealing lid 46 which seals the periphery of the holding plate 43 by lowering by the hydraulic cylinder 45 at the top of the frame 42 to press the sealing 44. .

In addition, the frame 42 has a through-shaped charging portion 42c for charging the object to be cleaned on the side wall, and the sealing lid 46 comes through the charging portion 42c. A plurality of " b " shaped loading pins 46c capable of receiving and holding the bottom surface are integrally provided, and the holding plate 43 allows the loading pins 46c to be lowered past the holding plate 43. Grooves (43c) to the vicinity of the edge, the holding plate (43) to hold the object to be cleaned on the holding plate 43, the load pin 46c is mounted on the holding plate 43 as the lowering; Preferably has a grip portion 43a protruding upward from the outer circumference.

In addition, the reactor 40 further includes a safety pin 47 for supporting the sealing lid 46 closed through the frame 42 from above to prevent the sealing lid 46 from being lifted during cleaning. Preferably, the sealing lid 46 is provided with a plurality of guide holes 46a, the bottom of the reactor 40 is a plurality of upright rods 46b passing through the guide hole 46a is integrally installed It is preferable to make.

Referring now to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

The ultra-precision cleaning apparatus according to the present embodiment performs ultra-precision cleaning of the object to be cleaned using carbon dioxide in a supercritical fluid state as the main solvent. Pressure above 72.8 atmospheres), a fluid in a third state with a liquid-like dissolution capacity and a gas-like diffusion and conduction.

Therefore, the supercritical fluid can quickly penetrate into the microstructure when applied to the cleaning process to effectively remove organic and inorganic contaminants contained therein.

In addition, the ultra-precision cleaning apparatus according to the present embodiment is to maximize the cleaning effect by applying a co-solvent together with carbon dioxide in a supercritical state, as described in detail below.

Figure 1 shows an overall high precision cleaning apparatus according to a preferred embodiment of the present invention. In the following description, a well-known wafer is used as the object to be cleaned.

As shown in FIG. 1, the washing apparatus 1 according to the present embodiment includes a washing fluid supply unit 10, a heat exchanger 20 for mixing and cooling the washing fluid flowing from the washing fluid supply unit, and a heat exchanger thereof. A high pressure pump 30 for pressurizing the cleaning fluid from the furnace 20 to the supercritical state, and a reactor 40 for cleaning the wafer by the supercritical fluid from the high pressure pump 30. The cleaning fluid, which has been cleaned at 40, passes through the regeneration filter 50 and is returned to the cleaning fluid supply unit 10 through the return pipe 2a or discharged to the outside.

In the present embodiment, the cleaning fluid supply unit 10 includes a main solvent reservoir 11 for storing carbon dioxide as a main solvent, a cooler 12 for cooling the main solvent, and a main solvent past the cooler 12. It is comprised by the main solvent conveyance pump 13 which conveys to the said heat exchanger 20.

In addition, the cleaning fluid supply unit 10 according to the present embodiment, the co-solvent supply source 15 and the co-solvent metering transfer pump for quantitatively transferring the co-solvent of the supply source 15 to the heat exchanger 20 described above. (16a, 16b) further comprising a co-solvent source (15) consisting of two reservoirs (15a, 15b) storing two different co-solvents.

In addition, the heat exchanger 20 is connected to the main solvent transfer pump 13 and the co-solvent metering pump (16a, 16b) by a pipe (2) is configured to receive and mix the main solvent and the co-solvent and to cool have.

In the present specification, the conduit 2 generally refers to a pipe conduit connecting the components of the washing apparatus 1 according to the present embodiment, but the conduits for returning and discharging the used washing fluid are respectively the return conduit 2a and It is described separately as the discharge line 2b.

In the present embodiment, the heat exchanger 20, as shown in Figure 2, has a magnetic seal-type scrubber 22 to more effectively mix the main solvent and the co-solvent, and inside the heat exchanger The installed cooling line 24 cools the mixed fluid more effectively. At this time, the cooling line 24 and the above-mentioned cooler 12 are configured to circulate the ester by using a chiller.

In addition, this heat exchanger 20 is provided with the pressure gauge 26 and the temperature sensor 27 which were installed in order to adjust the pressure and temperature in itself.

On the other hand, the washing fluid mixed and cooled in the heat exchanger 20 enters the reactor 40 having the structure shown in FIG. 3 through the conduit 2 while being in a supercritical state by the high pressure pump 30.

The reactor 40 is a portion in which the wafer is cleaned by the supercritical fluid, and can rotate the holding plate 43 on which the wafer (w; see FIGS. 3 to 4b) is seated and held to maximize the cleaning efficiency of the wafer. It is structured.

3, 4a and 4b is a view for explaining the structure of the reactor 40, Figure 3 is an exploded perspective view of the reactor, Figure 4a is a cross-sectional view showing the reactor in an open state without cleaning, 4B is a cross-sectional view of the reactor 40 in a sealed state for cleaning, which will be described later for cleaning.

As shown in Figs. 3, 4A and 4B, the reactor 40 includes a frame 42 having a concave cleaning space 42a at the bottom of which the cleaning is performed, and a driving part 5 outside the frame; 3 is provided with a wafer holding plate 43 rotated by the frame 40 in the cleaning space 42a while being rotatably installed in the frame 40.

In addition, the reactor 40 is provided on the sealing sheet 42b of the frame 42 at the outer periphery of the upper end of the cleaning space, and has a circular sealing 44 surrounding the wafer holding plate 43. .

In addition, the reactor 40 has a sealing lid 46 on its own upper portion that pressurizes the sealing to seal the periphery of the wafer holding plate 43, and in this embodiment, the sealing lid 46 is a frame. (42) The sealing cylinder 44 is pressed by the hydraulic cylinder 45 at the upper end to selectively seal the periphery of the holding plate 43.

In other words, the sealing lid 46 is provided at the end of the cylinder rod 45a of the hydraulic cylinder 45 to be selectively engaged with the sealing 44, and the selective engagement is a wafer holding plate 43. ) Serves to seal the surrounding cleaning space 42a into a space suitable for cleaning.

In this case, a plurality of guide holes 46a (only shown in FIG. 3) are formed at the edges of the sealing lid 46, and a plurality of upright rods 46b passing through the guide holes 46a are formed at the bottom of the reactor 40. ) Is installed to prevent the weakening of the sealing force caused by the movement of the sealing lid 46 more strongly.

In addition, the reactor 40 according to the present embodiment is a safety pin for supporting the sealing lid 46 closed through the frame 42 of the reactor as a safety means for preventing the sealing lid 46 from being lifted during cleaning ( 47) further.

As shown in Figure 4, the safety pin 47 is configured to be inserted deep into the frame 42 by the user's operation from the outside of the frame 42.

On the other hand, the reactor 40 is configured to automatically seat the wafer charged from the outside on the holding plate 43, the following description of the automatic seating structure of the wafer provided in the reactor 40 This will be done.

The reactor 40 has a through-type charging portion 42c (see FIG. 1) allowing the loading of the wafer on the side wall of the frame 42, and the sealing lid 46 receives the wafer from the outside on its bottom surface. Three " b " shaped loading pins 46c that can be retained are integrally provided.

In addition, the aforementioned wafer holding plate 43 has grooves 43c near the edge thereof to allow the loading pins 46c to be lowered past the holding plate 43, and the loading pins 43c. By passing these grooves 43c, the wafer held by the loading pin 46c is automatically seated on the wafer holding plate 43. As shown in FIG.

In addition, a grip portion 43a is formed at an outer circumferential portion of the wafer holding plate 43 to protrude upward to prevent the wafer from being separated due to the rotation of the holding plate 43.

In the foregoing description, the loading pin 46c is "b" shaped so that after the loading pin 46c is lowered, it does not interfere with the rotation of the retaining plate 43, which is shown in FIGS. The illustration of 4b will be fully understood by those skilled in the art.

On the other hand, the wafer automatically seated on the holding plate 43 as described above, is cleaned by the supercritical fluid introduced through the heat exchanger 20 and the high-pressure pump 30 mentioned above, according to the present embodiment The reactor 40 is configured to spray the supercritical fluid onto the wafer by a ring sprayer 48 in a shape surrounding the holding plate 43.

The spraying unit 48 is provided with a plurality of spray holes 48a formed at a uniform size and spacing on the surface, as best shown in Fig. 5, to heat shock or clean the wafer placed on the holding plate. It can prevent enough imbalance of condition.

Referring back to FIG. 1, the reactor 40 is connected to a conduit 2 through which the used cleaning fluid flows, and one of the branch conduits branched from the conduit 2 is connected to the regeneration filter 50. And, the other one constitutes the discharge pipe (2b).

In addition, the regeneration filter 50 separates the contaminants from the used regeneration fluid and sends the regenerated fluid to the heat exchanger 20 mentioned above through the return pipe 2a, and the contaminants are discharged from the pollutant 2c. Discharge to the outside through.

At this time, the regeneration filter 50 is provided with the pressure gauge 52 and the temperature sensor 54 for adjusting the pressure and temperature in itself.

Now, on the basis of the foregoing description and drawings, the operation of the cleaning apparatus will be described in detail.

When the worker seats the cassette containing the wafer to be cleaned in the loading cassette unit 5 shown in FIG. 1, the transfer robot 6 of FIG. 1 floats the wafer at the lowermost end of the cassette one by one and places the wafer on the sorter 7 Determine and fix the loading direction.

Thereafter, the wafer transfer robot 16 puts the wafer whose loading direction is determined on the loading pin 46c of the sealing lid 46 through the penetrating charging portion 42c.

When it is confirmed that the wafer is held by the loading pin 46c, the cylinder rod 45a of the cylinder 45 is lowered, and the cleaning space 42a around the wafer holding plate 43 is opened by the sealing lid 46. At this time, the loading pin 46c of the sealing lid 46 serves to securely seat the wafer on the holding plate 43 while descending past the wafer holding plate 43 (FIG. 3, FIG. 4a and 4b)

When the mounting of the wafer is completed, the safety pin 47 of the reactor 40 is closed, and then the cleaning process is performed through the flow of the cleaning fluid.

First, the main solvent transfer pump 13 and the cosolvent fixed quantity transfer pumps 16a and 16b of the cleaning fluid supply unit 10 send the main solvent and the cosolvent to the heat exchanger 20.

The main solvent and the co-solvent introduced into the heat exchanger 20 are mixed and cooled in the heat exchanger 20 and then sent to the high pressure pump 30 through the conduit 2.

In the high-pressure pump 30, the cleaning fluid mixed in the heat exchanger 20 is pressurized to the required pressure to change to a supercritical state, and the pressure at this time is checked by the reactor pressure gauge 49a.

Meanwhile, the supercritical fluid from the high pressure pump 30 enters the reactor 40 and is sprayed through the ring spray unit 48 in the reactor 40 to clean the wafer.

At this time, the temperature of the supercritical fluid to be reacted is checked by the reactor temperature sensor 49b, the temperature of which is an external heater 49c (see FIG. 1) installed upstream of the reactor and a heater inside the reactor 40 (not shown). Up to 200 ° C., and heat dissipation outside the reactor is inhibited by a cooling line 8 installed around the reactor 40. At this time, the cooling line 8 around the reactor 40 is configured to circulate the antifreeze using the reactor chiller.

On the other hand, when the cleaning is completed, the cleaning fluid used for cleaning is discharged to the outside of the reactor 40, again, the rinsing process to receive the pure carbon dioxide and solvent additives from the fluid supply unit 10 to clean the wafer To start.

At this time, the fluid used in the rinsing process is also made through the ring sprayer 48 inside the reactor, and the ring sprayer 18 allows the cleaning fluid to contact the wafer surface uniformly, resulting in heat imbalance. Prevents thermal cracking and uneven cleaning of the wafer.

When the rinse process is completed, the rotating wafer holding plate 43 is stopped, and the internal pressure of the reactor 40 is purged to atmospheric pressure.

When the operator confirms that the air pressure in the reactor 40 is equal to atmospheric pressure, the operator opens the safety pin 47 of the reactor 40 and opens the sealing lid 46 of the reactor 40 using the cylinder 45.

At this time, the wafer is lifted by the loading pin 46c, which hangs on the sealing lid 46, and then removed by the transfer robot 6 mentioned above.

On the other hand, the cleaning fluid discharged from the reactor 40 is returned through the regeneration filter (2) through the return pipe (2a) or is discharged to the outside through the discharge pipe (2b).

In addition, the cleaning device 1 according to the present embodiment is provided with safety means to prevent the danger caused by the use of a high pressure fluid.

That is, as shown in FIG. 1, the cleaning device 1 includes a heat exchanger relief 21 and a reactor lubricator 41 installed in the heat exchanger 20, the reactor 4, and the regeneration filter 50, respectively. And a filter relief 61, in which the cleaning fluid is discharged to the outside when the pressure inside the filter becomes equal to or higher than the predetermined pressure.

On the other hand, valve elements such as on-off valves, check valves or components such as pressure gauges that are not indicated in Figure 1 are apparent to those skilled in the art or less relevant to the spirit of the present invention, the detailed description thereof is omitted herein. lost.

As described above, according to the present invention, the spray structure of the supercritical fluid in the reactor and the structure of the rotating holding plate enable more uniform and efficient cleaning, and the nebulizer for spraying the supercritical fluid It takes the form of a circular ring having a plurality of spray holes having a constant size and spacing, and has the effect of preventing the thermal crack and the imbalance of the cleaning state caused by the heat imbalance in the conventional cleaning device, the cleaning space is substantially clean The sealing of can be made very surely, and in addition, it has the effect of being made automatically from the loading of the to-be-cleaned object to the sealing of the cleaning space.

Claims (5)

A cleaning fluid supply unit (10) for storing and supplying at least one cleaning fluid; A heat exchanger (20) for mixing and cooling the cleaning fluid flowing from the cleaning fluid supply unit (10); A high pressure pump 30 for pressurizing the cleaning fluid from the heat exchanger 20 in a supercritical state; A reactor 40 for cleaning the object to be cleaned using the supercritical fluid from the high pressure pump 30; Means for treating the cleaning fluid used in the reactor (40), The reactor 40 includes a holding plate 43 on which the to-be-cleaned object is seated and held so that the object to be cleaned is uniformly washed as a whole, a drive unit 5 for rotating the holding plate 43, and the And a spraying unit (48) for spraying the supercritical fluid into the wash object held by the holding plate (43). The method of claim 1, The to-be-cleaned object held in the holding plate 43 in the reactor 40 is a circular wafer, The spray unit 48 spraying the supercritical fluid to the object to be cleaned is a ring spray unit having a plurality of spray holes 48a on a surface at regular intervals and sizes, The ring-type spraying part (48) is a super-precision cleaning device using a supercritical fluid, characterized in that installed in the form of surrounding the circumference of the holding plate (43) inside the reactor (40). The method of claim 1 or 2, wherein the reactor 40, A frame 42 having a concave cleaning space 42a under which cleaning is performed; A holding plate (43) rotatably installed by the driving unit (5) inside the cleaning space (42a); A sealing 44 disposed on the sealing sheet 42b of the frame 42 at an outer circumference of the upper end of the cleaning space 42a and disposed to surround the wafer holding plate 43; Supercritical, characterized in that it comprises a sealing lid 46 for sealing the periphery of the holding plate 43 by lowering by the hydraulic cylinder 45 of the upper frame 42 to press the sealing 44 Ultra-precision cleaning device using a fluid. The method of claim 3, wherein The frame 42 has a through-shaped charging portion 42c for charging the object to be cleaned on the side wall, The sealing lid 46 is integrally provided on the bottom with a plurality of "b" shaped loading pins 46c that can receive and hold the object to be washed through the charging portion 42c. The retaining plate 43 has grooves 43c near the edges to allow the loading pins 46c to descend after the retaining plate 43, As the loading pin 46c is lowered, the holding plate 43 protrudes upward from an outer circumferential part of the holding plate 43 so as to hold the object to be cleaned on the holding plate 43 on the holding plate 43. Ultra precision cleaning device using a supercritical fluid, characterized in that it comprises a). The method of claim 4, wherein The reactor 40 further includes a safety pin 47 for supporting the sealing lid 46 closed through the frame 42 from above to prevent the sealing lid 46 from being lifted during cleaning, The sealing lid 46 is provided with a plurality of guide holes 46a, the bottom of the reactor 40 is characterized in that the plurality of upright rods 46b passing through the guide hole 46a is integrally installed. Ultra-precision cleaning device using a supercritical fluid.