JPS622455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wafer washing and drying apparatus that accommodates and rotates a large number of semiconductor wafers, washes them, centrifugally dehydrates them, and dries them.

Processes such as photolithography, thermal diffusion, and oxide film formation in the manufacturing process of semiconductor products are performed on the wafer surface, so dust and dirt that adhere to the wafer surface before each process can cause a decrease in yield after each process. It's getting old.

Therefore, before each processing step, the wafers are cleaned in advance using a wafer cleaning and drying device, and increasing the cleaning effect of this cleaning and drying device improves yield, and by increasing processing capacity, productivity can be increased. I can do it.

A conventional wafer cleaning/drying apparatus is shown in FIGS. 1 and 2 as a vertical sectional view and a plan sectional view. Reference numeral 1 denotes a cylindrical cleaning container with an open top, supported on a pedestal (not shown) in a vibration-proof manner, and provided with an exhaust port 2 at the bottom. Reference numeral 3 denotes an electric motor supported on the bottom side of the cleaning container 1 by a support frame 5, and the shaft end of a rotating shaft 4 passes through the center of the bottom and projects upward. Reference numeral 6 denotes a turntable which is fixed to the shaft end of the rotary shaft 4 and rotated, and mounting seats 7 are fixed to the upper surface of the turntable at a plurality of positions (four positions in the illustrated example) at equal intervals in the circumferential direction. Reference numeral 8 denotes a rotating frame fixed on each mounting seat 7, on the inside of which accommodating portions 8a are arranged at multiple locations (four locations in the example shown) at equal intervals in the circumferential direction, and on the back thereof, there are exclusion holes 8b. is open. Reference numeral 9 denotes a plurality of storage tools that are fitted and held in each of the storage portions 8a from the inside, and wafers 10 are inserted and stored in the multi-stage radial holding grooves 9a with gaps in the vertical direction, respectively.
An exclusion hole 9a is bored in the back. 11 is a lid that is placed over the cleaning container 1 through a gasket 12; 13 is a nozzle mounting rod that is attached to the center of the lower surface of the lid and extends downward, and is located in the center of the cleaning container 1; The nozzles are fixedly fixed, and the flow holes 13a communicate with these nozzles. A connecting pipe 15 enters the lid 11 from the outside and is connected to the flow hole 13a.

The cleaning and drying of the wafer 10 using the conventional apparatus described above was performed as follows. First, the turntable 6 is rotated at low speed by the electric motor 3, and cleaning liquid is sprayed from each nozzle 14. Each wafer 10 is rotated while being cleaned by the sprayed cleaning liquid. When the cleaning is finished, the turntable 6 is rotated at high speed by the electric motor 3, and the cleaning liquid adhering to the surface of the wafer 10 is scattered outward by centrifugal force. At the same time, drying gas is blown out from the nozzle 14 to clean the surface of the wafer 10. dry. At this time, the scattered cleaning liquid mixes with the dry gas to form a mist and is discharged from the exhaust port 2 at the bottom of the cleaning container 1.

However, in the conventional apparatus described above, the rotating shaft 4 of the turntable 6 is arranged concentrically with the cylindrical cleaning container 1, and the dry gas jetted from the nozzle and the cleaning liquid jetted onto the wafer 10 and blown away by centrifugal force are mixed. The atomized mixture is discharged from the turntable 6 before being discharged from the exhaust port 2 at the bottom of the cleaning container 1.
Also, due to the high speed rotation of the rotating frame 8, the gap between the rotating frame 8 and the inner wall of the cleaning container 1 is reduced. Due to the secondary flow caused by the non-uniformity of the flow velocity of the atomized mixture in this state, a vertical flow is generated along the inside of the side plate 1a of the cleaning container 1, and it is not discharged quickly, so the cleaning container The inner surface of the side plate 1a and the wafer 10
There was a drawback that the atomized material that came into contact with the wafer 10 and became contaminated circulated in the direction of the arrow A and re-adhered to the surface of the wafer 10, causing contamination.

In this invention, the center of the turntable is shifted with respect to the side plate of the cleaning container so that the gap with the outer circumference of the turntable is from a small part to a part where it becomes large, and A discharge port is provided on the side of the small gap, and the atomized mixture of cleaning liquid along the inner surface of the side plate of the cleaning container is quickly discharged from the discharge port, preventing re-contamination of wafers, enhancing the cleaning effect, and improving yield. The purpose of the present invention is to provide a wafer cleaning/drying apparatus.

3 and 4 are a longitudinal sectional view and a plan sectional view of a wafer cleaning and drying apparatus according to an embodiment of the present invention, and are 3-10, 12-15, 8a, 8b, 9
a and 9b are the same as those of the conventional device described above. 2
Reference numeral 1 denotes a cleaning container with an open top, and a side plate 21a is formed in a spiral shape concentrically with the axial center of the turntable 6, and the side plate 21a is formed in a spiral shape concentrically with the axial center of the turntable 6, from the side with a large gap to the outer circumference of the turntable 6 to the side with a small gap in the rotation direction. An exhaust port 22 is provided across the section, and a drain port 23 is provided at the bottom.

24 is a lid that connects the cleaning container 2 through the gasket 12.
1, and a nozzle mounting rod 13 is protruded downward at the center of the same axis as the turntable 6.

The cleaning and drying of the wafer 10 using the apparatus of the above-mentioned embodiment is performed in the same manner as in the case of the conventional apparatus. First, the turntable 6 is rotated at a high speed, and wafer cleaning liquid is simultaneously jetted from each nozzle 14 to uniformly clean each wafer 10 of each storage tool 9 rotated by the turntable 6. At this time, the cleaning liquid that has been spouted out, cleaned the wafer 10, and passed outward is mainly discharged from the drain port 23 at the bottom. Next, when cleaning of the wafer 10 is finished, drying gas is ejected from the nozzle 14, and at the same time, the turntable 6 is rotated at high speed and the wafer 10 is also rotated at high speed. As a result, the residual cleaning liquid adhering to the wafer 10 and storage tool 9 is blown off by the centrifugal force, and the wafer 10 is dried by the drying gas.

As shown in FIG. 4, the turntable 6 and storage tool 9 rotating in the direction of arrow B correspond to the impeller of a centrifugal blower, while the cleaning container 21 corresponds to the casing, and the nozzle mounting rod 13 located at the center of rotation The dry gas ejected from each nozzle 14 of
The spiral-shaped side plate 2 circulates axially symmetrically with respect to the outer circumference of the
They merge inside 1a, pass in the direction of arrow C, and are discharged from the exhaust port 22.

In this way, the cleaning container 21 has a spiral shape, so that the flow velocity v of the drying gas passing in the direction of arrow C is almost constant, and secondary flow, that is, upstream and downstream flow in the axial direction, is prevented from occurring. Therefore, the cleaning liquid remaining on the surface of the wafer 10 is blown away by the centrifugal force and becomes a mist, which forms a mixture with the dry gas and is quickly discharged from the exhaust port 22. This prevents the atomized mixture from flowing along the side plate of the cleaning container and remaining there for a long time, circulating upward and re-contaminating the wafers 10, as in the prior art.

FIG. 5 is a sectional plan view of a wafer cleaning and drying apparatus according to another embodiment of the present invention. Reference numeral 26 denotes a cleaning container whose top is open and surrounded by a side plate 26a in a cylindrical shape, and the axial center Q of the turntable 6 is offset from the axial center P of this cleaning container. m is the eccentricity value. Thereby, the gap between the side plate 26a and the outer circumference of the turntable 6 is made to extend from a small portion to a large portion. A discharge port 27 is provided from the side of the side plate 26a where the gap is large to the side where the gap is small in the direction of rotation.
Side plate 26a on the side of the small gap part of the discharge port 27
A blocking plate 28 is provided to protrude inwardly to prevent the atomized air-fuel mixture from circulating and improve its discharge. In addition, if a guide plate 29 is further provided on this weir plate 28 as shown by a chain line, the fluid flow in this part will become much smoother. Since the cleaning container 26 is cylindrical, it can be made cheaper than the spiral-shaped cleaning container 21 described above.

As described above, according to the present invention, the center of the turntable is shifted so that the gap between the outer circumference of the turntable and the side plate of the cleaning container ranges from a small part to a large part, and a gap is created in the side plate. Since the exhaust port is provided from the side with a large gap to the side with a small gap in the direction of rotation, the atomized mixture of cleaning liquid flowing along the inside of the side plate of the cleaning container is quickly exhausted from the exhaust port, making it possible to eliminate It is prevented from remaining in the cleaning container for a long time and being processed, adhering to the wafer again and causing re-contamination, improving the cleaning effect and improving the yield in the next processing step.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventional wafer cleaning and drying apparatus, and FIG. 2 is a cross-sectional view taken along the - line in FIG.
3 is a longitudinal cross-sectional view of a wafer cleaning and drying apparatus according to one embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the - line in FIG. 3, and FIG. 5 is a wafer cleaning and drying apparatus according to another embodiment of the present invention. FIG. 4 is a sectional view corresponding to FIG. 3...Electric motor, 6...Turntable, 8...
Rotating frame, 9...Storage equipment, 10...Wafer,
13... Nozzle mounting rod, 14... Nozzle, 21...
...Cleaning container, 21a...Side plate, 22...Exhaust port,
24... Lid, 26... Washing container, 26a... Side plate, 27... Outlet, 28... Blocking plate. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A cleaning container having a cylindrical shape and having an open top covered with a lid, the axial center of which is aligned with the inner surface of the side plate of the cleaning container so that the gap with the outer circumference is from a small part to a large part. a turntable that is rotated while being displaced and disposed below the cleaning container;
A rotating frame fixed on this turntable, held at equal intervals in the circumferential direction on this rotating frame,
A plurality of storage devices each storing a large number of wafers with a gap between the top and bottom, and a plurality of nozzles attached to the center side of the lower surface of the lid, located at the axis of the rotating frame. The side plate is provided with a nozzle mounting rod for injecting cleaning liquid and then drying gas from each of the nozzles, and the side plate has an exhaust port extending from the side of the larger gap to the side of the smaller gap in the direction of rotation. A wafer cleaning/drying device characterized by being provided with. 2. The wafer cleaning and drying apparatus according to claim 1, wherein the cleaning container has a side plate formed in a spiral shape, and the axial center of the turntable is aligned with the center of the spiral. 3. The wafer cleaning and drying apparatus according to claim 1, wherein the cleaning container has a cylindrical side plate, and the axial center of the turntable is offset from the axial center of the cylinder.