KR101445680B1 - Batch type cleaning apparatus for circumvolve wafer and method for cleaning - Google Patents

Abstract

A batch type cleaning apparatus and a cleaning method thereof for causing a wafer to be evenly cleaned by rotating the wafer. A batch type cleaning apparatus capable of rotating a wafer includes a cleaning tank in which a cleaning liquid is contained, a plurality of slots each of which accommodates a plurality of wafers in a vertical direction, and a lifting and lowering unit for moving the plurality of wafers into and out of the cleaning tank And a wafer rotating unit provided in the lift unit for rotating the wafer by spraying purge gas onto the wafer. Therefore, by rotating the wafer, the positions of the first and second potions, which have been previously acquired in the cleaning liquid, are changed, so that the contact time between the wafer and the cleaning liquid is made uniform, and the surface of the wafer can be uniformly cleaned.

Batch type cleaning device, wafer rotation

Description

BATCH TYPE CLEANING APPARATUS FOR CIRCUM VOLVE WAFER AND METHOD FOR CLEANING [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a batch type cleaning apparatus and a cleaning method thereof, and more particularly, to a batch type cleaning apparatus and a batch type cleaning method using the same.

In general, a semiconductor device can be manufactured by repeatedly performing a deposition, a photolithography, an etching process, and the like using a wafer, for example, a silicon wafer. Contaminants such as various particles, metal impurities, organic impurities, etc. may remain on the wafer during the processes. Since contaminants adversely affect the yield and reliability of semiconductor devices, a cleaning process is performed to remove contaminants remaining on the wafer during semiconductor manufacturing.

The cleaning method for cleaning semiconductor wafers can be largely divided into a dry cleaning method and a wet cleaning method. Among them, the wet cleaning method is a cleaning method using various chemical solutions, and a single wafer type in which a wafer is cleaned in a batch unit and a single wafer unit.

The batch type cleaning apparatus removes a contamination source by immersing a plurality of wafers at a time in a receiving tank containing a cleaning liquid. However, in the conventional batch type cleaning apparatus, it is not easy to cope with the trend of enlargement of wafers and there is a disadvantage that the cleaning liquid is used in many cases. In addition, when one of the wafers is broken during the cleaning process, the batch type cleaning apparatus may damage the entire wafer in the same receiving chamber and there is a risk that a large number of wafer defects may occur.

A single-wafer type cleaning apparatus is a cleaning apparatus for processing a wafer by a single wafer. The cleaning apparatus removes contamination sources by centrifugal force generated by rotation of the wafer and pressure applied to the cleaning liquid by jetting the cleaning liquid onto the wafer surface rotated at a high speed spinning method).

A batch type cleaning apparatus, which is usually called a wet station, is subjected to a series of processing steps while the wafer is transferred along the processing path of the cleaning processing section. The cleaning processing unit is provided with a plurality of cleaning units in which a cleaning liquid mixed with various chemical liquids at a predetermined ratio is received to perform a cleaning process with respect to the wafer. In order to remove the chemical liquid from the wafer after the chemical liquid cleaning process has been completed, A rinsing unit is provided in which a rinsing process is performed.

On the other hand, the conventional batch type cleaning apparatus is immersed in the cleaning tank in a state where a plurality of wafers are simultaneously mounted on the lift unit by 25 sheets or 50 sheets, and the cleaning process is performed.

Here, the wafers are arranged in the direction perpendicular to the cleaning liquid, so that the lower portion of the wafer is first taken in the cleaning liquid and then drawn out later, so that the contact time with the cleaning liquid differs between the upper and lower portions of the wafer. As a result, the cleaning effect of the wafer is different according to the contact time with the cleaning liquid, so that the wafer is not uniformly cleaned over the entire surface.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a batch type cleaning apparatus capable of uniformly cleaning the surface of a wafer and improving cleaning efficiency by making the contact time between the wafer and the cleaning liquid uniform.

The present invention also provides a cleaning method capable of uniformly maintaining the contact time between the wafer and the cleaning liquid in the above-described batch type cleaning apparatus.

According to embodiments of the present invention for achieving the object of the present invention, a batch-type cleaning apparatus capable of rotating a wafer includes a cleaning tank containing a cleaning liquid, a plurality of slots each accommodating a plurality of wafers in a vertical direction And a wafer rotating unit which is provided in the lift unit and rotates the wafer by spraying purge gas onto the wafer, so that the plurality of wafers are moved into and out of the cleaning tank.

In the embodiment, the wafer rotating portion may include a plurality of purge holes formed in the lower portion of each of the slots in the lift unit to inject purge gas into the respective wafers, a purge line for supplying purge gas to the plurality of purge holes, And a purge gas supply unit for selectively supplying the purge gas to the line. The purge gas may be a stable gas that does not chemically react with the cleaning liquid and the wafer. For example, the purge gas may be nitrogen gas.

In an embodiment, the slot is formed such that a portion of the wafer contacts the bottom of the slot, and the purge hole is formed in the slot portion in contact with the wafer.

In an embodiment, the lift unit has a slot portion for supporting at least three points below each wafer received in the vertical direction, and the purge hole is formed in any one of the slot portions. Of course, it is also possible that the purge holes are formed in the entirety of the plurality of slots.

In an embodiment, the purge hole ejects purge gas eccentrically from the radial direction of the wafer such that the wafer is rotatable in the slot by the injection of the purge gas.

According to another aspect of the present invention, there is provided a batch-type cleaning method for cleaning a plurality of wafers to be cleaned in a vertical direction to a cleaning liquid, A cleaning step for removing contamination on the surface of the wafer by immersing the wafer surface for a predetermined time or longer is performed. Before the wafers having been cleaned are taken out from the cleaning liquid, a position of the wafers is reversed by rotating the wafers in a vertically erected state by injecting a purge gas to the lower portion of the wafers, From the cleaning liquid. Therefore, the cleaning liquid can be uniformly cleaned on the surface of the wafer by making the contact time between the wafer and the cleaning liquid relatively uniform.

In an embodiment, the wafer rotation step is performed for a period of time before the cleaning of the wafer is completed and the wafer is withdrawn. Here, the wafer rotation step rotates the wafer by 180 DEG so that the position of the part first contacted with the cleaning liquid on the wafer and the position of the later contacted part can be reversed. Alternatively, the wafer is rotated a plurality of times so that when the wafer is taken out of the cleaning liquid, the wafer is rotated so that the position of the first portion of the wafer received in the cleaning liquid and the position of the later acquired portion are reversed.

According to the present invention, firstly, by rotating the wafer, it is possible to change the positions of the first portion and the second portion that are previously received in the cleaning liquid, and to maintain the contact time of the wafer with the cleaning liquid uniformly with respect to the wafer surface .

Further, since the contact time of the cleaning liquid is uniform, the surface of the wafer can be uniformly cleaned and the cleaning efficiency can be improved.

The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to or limited by the embodiments.

1 is a perspective view illustrating a batch type batch type cleaning apparatus according to an embodiment of the present invention. Fig. 2 is a sectional view of the lift unit taken along the line I-I in the cleaning apparatus of Fig. 1, and Fig. 3 is a side sectional view of the lift unit taken along the line II-II in the cleaning apparatus of Fig. 4 and 5 are front views of a wafer for explaining the operation of the wafer rotating part according to the embodiments of the present invention. 6A and 6B are front views of a wafer for explaining the operation of the wafer rotating unit according to an embodiment of the present invention.

Hereinafter, a batch type cleaning apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6B.

Referring to the drawings, a batch type cleaning apparatus includes a cleaning tank 20, a lift unit 100, and a wafer rotation unit 150.

The cleaning tank 20 is formed to have a sufficient size so that a plurality of wafers 10 can be simultaneously immersed in the cleaning liquid, while the cleaning liquid is received to provide a space in which the cleaning process for the wafer 10 is performed. For example, the cleaning tank 20 may be formed of quartz or synthetic resin. In addition, the cleaning tank 20 may be formed of a material that does not chemically react with the cleaning liquid. For example, Substantially non-reactive < / RTI > materials may be used. However, the shape and structure of the cleaning tank 20 can be variously changed according to the conditions required for cleaning the wafer 10 and the design specifications.

In the present invention, the cleaning liquid refers to a solution for cleaning contaminants remaining on the wafer 10. The cleaning liquid is a solution that is determined depending on the type of the wafer 10 and the type of the material to be removed, Are mixed at a certain ratio. For example, the cleaning liquid may be an etchant for etching a thin film on the surface of the wafer 10, and may be an aqueous solution of hydrogen fluoride (HF), a solution of sulfuric acid (H2SO4) or nitric acid (H3PO4) standard clean-1) solution.

The lift unit 100 is a device capable of moving the wafer 10 into and out of the cleaning tank 20 and includes a guide unit 110 capable of vertically holding the wafer 10, A lifting and lowering driving unit 130 for transmitting a driving force for lifting and lowering the lift unit 100 and a lifting and lowering unit 130 provided in the guide unit 110 to support the wafer 10, And the wafer rotating unit 150 rotates in a state of being supported by the guide unit 110.

The guide part 110 includes a plurality of slot parts 111 and 112. Each of the slots 111 and 112 may have a plurality of slots 111a and 112a at a plurality of points below the wafer 10 received in a direction perpendicular to the guide 110. In this specification, A method of supporting the wafer 10 at three points below the wafer 10 will be described as an example.

A plurality of slot parts 111 and 112 according to an embodiment of the present invention includes a first slot part 111 for supporting a lower portion of the wafer 10 and a second slot part 111 for spacing a predetermined distance from the first slot part 111, And a second slot part 112 provided on both sides of the first slot part 112. [

Here, the guide part 110 is formed in the first slot part 111 so that the second slot part 112 can stably support the side surface of the wafer 10 . In addition, the guide unit 110 is configured to accommodate the wafers 10 in a vertical direction by a unit of a single unit, and to accommodate the wafers 10 with a predetermined distance therebetween. 2 and 3, the first and second slots 111a and 112a may be formed by minimizing the contact area with the wafer 10 and by positioning the wafer 10 in the first and second slots 111a and 112a, And has an inclined surface to prevent the wafer 10 from colliding with the first and second slots 111a and 112a in and out of the second slots 111a and 112a. 2, the second slot 112a is substantially the same as the first slot 111a shown in FIG. 3 when seen from a side view, and the second slot 112a is a portion indicated by a broken line in FIG. And is inclined downward toward the bottom so as to be spaced apart from the wafer 10 by a predetermined distance.

The wafer rotating part 150 rotates the wafer 10 by spraying a purge gas PG to the lower part of the wafer 10. The wafer rotating part 150 includes a purge hole 151 formed in the first and second slot parts 111 and 112 and a purge line 152 for supplying purge gas PG to the purge hole 151, And a gas supply unit 155.

The purge gas PG may be a gas that does not chemically react with the wafer 10 and the cleaning liquid. For example, the purge gas PG may use nitrogen gas (N2) .

The purge hole 151 is formed in each of the first and second slots 111a and 112a so as to inject purge gas PG into the respective wafers 10, , 112a, just under the position where the wafer 10 is seated. Here, the purge hole 151 may be formed in both the first and second slot parts 111 and 112, as shown in FIG. Alternatively, the purge hole 151 may be formed only in one of the first slot portion 111 and the second slot portion 112, as shown in FIG.

The purge line 152 communicates the purge hole 151 to supply the purge gas PG to the purge hole 151 and forms a long tube shape in the first and second slot parts 111 and 112. [ As shown in FIG. Here, the purge hole 151 may have various hole sizes to minimize the air pressure difference of the purge gas PG generated according to the distance from the position where the purge gas is injected.

The wafer rotating unit 150 rotates the wafer 10 in the first and second slots 111a and 112a to a predetermined height by ejecting purge gas PG to the wafer 10 through the purge hole 151. [ And the wafer 10 is rotated by the flow of the purge gas PG. Particularly, the wafer 10 rotates while being accommodated in the first and second slots 111a and 112a.

The direction in which the purge gas PG is injected in the purge hole 151 so as to allow the wafer rotating unit 150 to rotate the wafer 10 is a direction in which the purge gas PG is injected at a predetermined distance eccentrically in the radial direction of the wafer 10. [ . Alternatively, the purge hole 151 may inject the purge gas PG toward the circumference of the wafer 10 so that a force acts on the wafer 10 in a tangential direction.

Hereinafter, the operation of the wafer rotating unit 150 according to an embodiment of the present invention will be described with reference to FIGS. 4 to 6B. 6A and 6B show only the wafer 10 for explaining the operation of the wafer rotating unit 150. The components of the wafer rotating unit 150 and the cleaning apparatus are already described in FIGS. The detailed description thereof will be omitted.

6A and 6B, when the wafer 10 is received in the cleaning liquid for cleaning the wafer 10, the portion of the wafer 10 which first contacts the cleaning liquid is referred to as a lower portion 10b And the portion which is finally contacted is called the upper potion 10a.

The wafer rotating part 150 changes the positions of the upper potion 10a and the lower potion 10b of the wafer 10 so as to make the contact time of the wafer 10 uniform. That is, the wafer rotating unit 150 rotates the wafer 10 while the wafer 10 is vertically received in the lift unit 100, thereby reversing the positions of the upper potion 10a and the lower potion 10b. Therefore, when the wafer 10 is received in the cleaning liquid, the upper potion 10a is first brought into contact with the cleaning liquid. However, when the wafer 10 is taken out, the upper potion 10a is drawn first, The cleaning effect by the time when the surface of the wafer 10 is in contact with the cleaning liquid can be maintained uniformly.

The wafer rotating unit 150 does not operate during the cleaning of the wafer 10 and rotates the wafer 10 before the wafer 10 is cleaned and taken out from the cleaning tank 20 . Alternatively, the wafer rotating part 150 may rotate the wafer 10 selectively only when the wafer 10 is taken in the cleaning liquid and when it is drawn out from the cleaning liquid.

The wafer rotating unit 150 rotates the wafer 10 a plurality of times so that the positions of the upper potion 10a and the lower potion 10b are reversed when the wafer 10 is taken out from the cleaning liquid . Alternatively, the wafer rotating part 150 may be rotated slowly until the positions of the upper potion 10a and the lower potion 10b are reversed.

Although the present invention has been described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined in the following claims. It can be understood that

1 is a perspective view illustrating a cleaning apparatus and a wafer lift unit according to an embodiment of the present invention;

Fig. 2 is a cross-sectional view of a lift unit cut along the line I-I in Fig. 1; Fig.

3 is a side cross-sectional view showing a cross section of the lift unit cut along the line II-II in FIG. 1;

4 is a front view of a wafer for explaining a wafer rotating part according to an embodiment of the present invention;

4 is a front view of a wafer for explaining a wafer rotating part according to another embodiment of the present invention;

6A and 6B are views for explaining the operation of the wafer rotating unit according to an embodiment of the present invention.

Description of the Related Art

10: wafer 10a: first potion

10b: second potion 20: cleaning tank

100: lift unit 110:

111: first slot part 111a, 112a: slot

112: second slot part 115: support part

130: lift driving part 150: wafer rotating part

151: purge hole 152: purge line

155: Purge gas supply part

G: Clearance PG: Purge gas

Claims (8)

A washing tub containing a washing liquid; A lift unit including a plurality of slots each of which accommodates a plurality of wafers in a vertical direction, and moving up and down to move the plurality of wafers into and out of the cleaning tank; And A wafer rotating unit provided in the lift unit for spraying purge gas on the wafer to rotate the wafer inside the lift unit; Lt; / RTI > Wherein, A plurality of purge holes formed in the lower portion of each of the slots in the lift unit to inject purge gas into the wafer; A purge line for providing a purge gas to the purge hole; And A purge gas supply unit for selectively supplying purge gas to the purge line; Type cleaning apparatus. delete The method according to claim 1, The slot being formed such that a portion of the wafer is in contact, Wherein the purge hole is formed in the slot portion in contact with the wafer. The method according to claim 1, Wherein the lift unit has a slot portion for supporting at least three points below each wafer received in the vertical direction, Wherein the purge hole is formed in at least one of the slots. The method according to claim 1, Wherein the purge hole injects purge gas eccentrically to the radial direction of the wafer. Obtaining a plurality of wafers received in the lift unit in a vertical direction to the cleaning liquid; Immersing the cleaning liquid in the wafer for a predetermined period of time; Rotating the plurality of wafers only within the lift unit with the wafers vertically erected by injecting purge gas under the wafers in the cleaning step; And When the cleaning step is completed, withdrawing the wafer from the cleaning liquid; Lt; / RTI > The method according to claim 6, Wherein the wafer rotation step is performed for a period of time before withdrawing the wafer. The method according to claim 6, Wherein the wafer rotating step rotates the wafer such that, when the wafer is taken out of the cleaning liquid, the wafer is reversed such that the position of the wafer is first inverted and the position of the wafer is reversed.

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