JP3192951B2 - Semiconductor wafer drying equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer drying apparatus used for drying a semiconductor wafer after a chemical treatment and a water washing treatment.

[0002]

2. Description of the Related Art As is well known, a semiconductor wafer that has been subjected to a chemical treatment such as etching is subjected to a cleaning treatment with water.
After being dried, it is transferred to the next step. Conventionally, such a series of processes has been performed as follows.

The prior art will be described below with reference to FIGS. FIG. 3 is a plan view, and FIG. 4 is a front view.

[0004] In FIGS. 3 and 4, reference numeral 1 denotes a semiconductor wafer; 2, a holding table for holding a plurality of semiconductor wafers 1; 3, a first chemical solution tank filled with a first chemical solution. Numeral 4 denotes a second chemical tank filled with a second chemical liquid, and numeral 5 denotes a washing tank filled with water.
Reference numeral 6 denotes a cassette stage. Reference numeral 7 denotes a cassette placed on the cassette stage 6, on which a plurality of semiconductor wafers 1 after water washing are transferred from the holding table 2 and held.

[0005] Reference numeral 8 denotes a spin dryer, in which a holder 9 is provided. The holder 9 accommodates and holds a cassette 7 for holding the semiconductor wafer 1, rotates in a direction of an arrow A around a rotation center X in a state where the semiconductor wafer 1 is horizontal, and revolves the semiconductor wafer 1 in a horizontal plane. Has become.

In such a structure, first, a plurality of semiconductor wafers 1 held on a holding table 2 so as to be arranged with a predetermined interval between their main surfaces are placed in a first chemical solution tank. 3 and then a second treatment as indicated by arrow B1.
Is transferred to the chemical tank 4 for chemical treatment. Then, the plurality of semiconductor wafers 1 subjected to the chemical treatment are transferred to a washing tank 5 as shown by an arrow B2, and the chemical liquid is removed by washing in the washing tank 5.

[0007] Thereafter, the plurality of semiconductor wafers 1 are placed one by one on a cassette 7 placed on a cassette stage 6 by an arrow B3.
, And are similarly held so as to be arranged with a predetermined interval between the main surfaces. Then, the cassette 7 holding a plurality of semiconductor wafers 1 is transferred to a holder 9 in a spin dryer 8 as shown by an arrow B4 and stored and held.

Further, the holder 9 is rotated in the direction of arrow A around the rotation center X in a state where the arrangement direction of the semiconductor wafers 1 accommodated therein is vertical, that is, the main surface of the semiconductor wafer 1 is horizontal. Is done. The water adhering to the surface of the semiconductor wafer 1 is removed by being shaken off by the centrifugal force accompanying the rotation, and the semiconductor wafer 1 is dried.

However, in the above prior art,
Since the semiconductor wafer 1 to which water has been washed and to which moisture has adhered is transferred to the cassette 7 and then dried by the spin dryer 8, a part of the semiconductor wafer 1 is naturally dried during the transfer. Insufficient drying such as waking up and spots may occur. In addition, since the semiconductor wafer 1 is held in the cassette 7, when the wafer is rotated and dried by the spin drier 8, the moisture adhering to the semiconductor wafer 1 is blocked by the cassette 7 and the removal is not performed smoothly. However, there is a fear that insufficient drying may occur.

Further, since the cassette 7 is usually made of a synthetic resin material such as PFA (tetrafluoroethylene-perfluoroalkylvinyl ether), which is resistant to chemicals at the time of chemical treatment, the cassette 7 is rotated by the spin dryer 8. There is a possibility that dust or particles existing in the atmosphere may be attracted to and adhere to the charged cassette 7 or the semiconductor wafer 1 by causing static electricity therein.

Furthermore, since a plurality of semiconductor wafers 1 are dried at one time, the drying state of each semiconductor wafer 1 is different, and there is a possibility that a watermark may be formed due to insufficient drying. .

As described above, in the drying process in which a plurality of semiconductor wafers 1 are held in the cassette 7 and dried at a time by the spin dryer 8, there is a possibility that defective drying may occur, and it is difficult to improve the quality in the drying process. Had become.

On the other hand, when a large centrifugal force is applied to the plurality of semiconductor wafers 1 held in the cassette 7 so that the drying is performed reliably, the spin dryer 8 has a large rotation radius. The space occupied by the spin dryer 8 is the first chemical solution tank 3, the second chemical solution tank 4, and the washing tank 5.
Therefore, it is desired to reduce the required space as much as possible from the viewpoint of effective use of the limited space in the clean room. By the way, the average size of the spin dryer 8 for drying the 6-inch semiconductor wafer 1 is as follows.
The width is about 800 mm and the depth is about 800 mm.

[0014]

As described above, conventionally, a plurality of semiconductor wafers are transferred to a cassette, and the semiconductor wafer is rotated by a spin drier while being held in the cassette to remove water by shaking off water and dried. Insufficient drying such as stains caused by drying partly when changing, partial insufficiency of drying due to disturbed cassettes, dirt and particles attracted by static electricity and adhere to semiconductor wafers, and drying at the same time Due to the different drying state among the plurality of processed semiconductor wafers, insufficient drying occurs in some parts, resulting in a watermark or the like, and quality improvement in the drying processing is required. Furthermore, a spin dryer requires a large centrifugal force to ensure drying, but occupies a large space in a clean room. In view of such a situation, the present invention has been made, and an object of the present invention is to provide a semiconductor wafer drying apparatus in which problems such as poor drying are unlikely to occur, quality in a drying process can be improved, and space can be saved. I do.

[0015]

SUMMARY OF THE INVENTION A semiconductor wafer drying apparatus according to the present invention comprises a buffer tank for holding a semiconductor wafer having been subjected to a washing treatment in water, and a transfer for picking up and transferring semiconductor wafers one by one from the buffer tank. And a rotary drying unit that supports one semiconductor wafer transferred by the transfer unit so that the main surface is substantially horizontal, and rotates at a high speed in a horizontal plane to remove water. And
Further, the semiconductor wafer is washed with water while a plurality of the semiconductor wafers are placed on one holding table, and is held in the water in the buffer tank while being mounted on the holding table. Further, the semiconductor wafer is held in the buffer tank such that the main surface is vertical, and further, the transfer unit is configured to hold the semiconductor wafer in a state where the main surface is vertical. The semiconductor wafer is picked up from the inside of the buffer tank, and is transferred to the rotary drying unit while being changed so that the main surface of the semiconductor wafer is horizontal during the transfer. The semiconductor wafer is supported at a plurality of locations on the outer periphery and rotated in a horizontal plane.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 is a perspective view, and FIG. 2 is a plan view.

In FIGS. 1 and 2, reference numeral 11 denotes a disc-shaped semiconductor wafer, and 12 denotes a holding table for holding a plurality of semiconductor wafers 11, for example, a batch processing 25.
The semiconductor wafers 11 are arranged so as to provide a predetermined interval between their main surfaces, and are held vertically.

Reference numeral 13 denotes a first chemical solution tank in which a first chemical solution is filled.
Is immersed in the first chemical solution by a transfer device (not shown) while being held by the holding table 12. 14
Is a second chemical solution tank filled with a second chemical solution, which is similarly immersed in the first chemical solution and taken out and transferred by the transfer device as shown by an arrow C1 as indicated by arrow C1.
Is also immersed in the second chemical solution while being held by the holding table 12.

Reference numeral 15 denotes a washing tank filled with water for washing, and a plurality of semiconductor wafers taken out and transferred as shown by an arrow C2 after being immersed in a second chemical solution by a transfer device. 11 is immersed while being held by the holding table 12, and is washed with water. Note that the first chemical solution tank 13 and the second
Are disposed in accordance with the order of the processing steps.

A washing buffer tank 16 is provided adjacent to the washing tank 15.
Is supplied so that water for washing is overflowed, and the water inside is always replaced by newly supplied water. The washing tank 1 is located in the washing buffer tank 16.
The plurality of semiconductor wafers 11 cleaned in step 5
While the main surface is kept vertical to 2, the device is transferred by a transfer device as shown by an arrow C3 and stored in water.

On the other hand, reference numeral 17 denotes a transfer section provided adjacent to the washing buffer tank 26, and a vertical movement for linearly moving the wafer chuck mechanism 18 vertically in the vertical direction as shown by the arrow D in FIG. A mechanism 19 and a horizontal moving mechanism 20 for moving the vertical moving mechanism 19 linearly forward and backward in the horizontal direction as shown by an arrow E are provided. Reference numeral 21 denotes a guide rail of the vertical movement mechanism 19, reference numeral 22 denotes a drive section of the vertical movement mechanism 19, reference numeral 23 denotes a guide rail of the horizontal movement mechanism 20, and reference numeral 24 denotes a drive section of the horizontal movement mechanism 20.

The wafer chuck mechanism 18 includes a rotating arm 25 having one end supported by a vertical moving mechanism 19 and having a horizontal rotating shaft and rotating as shown by an arrow F. And an opening / closing chuck 26 provided at the other end. The rotation arm 25 is connected to a rotation drive unit 27.
The opening / closing operation is performed by the opening / closing chuck 26 by the chuck driving unit 28 as indicated by an arrow G.

Reference numeral 29 denotes a rotary drying unit provided adjacent to the transfer unit 17, a rotary table 30 for horizontally supporting the semiconductor wafer 11 on the upper surface side, and the rotary table 30 at 3000 rpm in the direction indicated by the arrow H. And a drive motor 31 that rotates at a high speed of up to 5000 rpm. On the upper surface of the turntable 30, a plurality of crank mechanisms 33 each having a chuck pin 32 for horizontally supporting the semiconductor wafer 11 erected at an end thereof are provided substantially in a radial manner.

The chuck pin 32 has a columnar shape, and is formed such that the rotation center side of the tip portion has an inclined surface on the lower side and a vertical surface on the upper side, and has a half-moon cross section. The chuck pin 32 moves forward and backward in the direction of the rotation center of the turntable 30 while maintaining a state of being arranged on the same circumference by the crank mechanism 33.

Further, a transfer device (not shown) is provided in the vicinity of the rotary drying unit 29, so that the semiconductor wafers 11 for which the rotary drying has been completed are sequentially sent to the next step. The operation of each mechanism and each unit described above is controlled by a control unit (not shown) based on the setting contents input during operation and control contents programmed in advance.

In the above-described structure, first, the semiconductor wafers 11 held on the holding table 12 so as to be vertically arranged with a predetermined interval between their main surfaces are placed in the first chemical solution tank 13. Then, it is transferred to the second chemical solution tank 14 while being held by the holding table 12, and is subjected to chemical treatment. The semiconductor wafer 11 that has been subjected to the chemical treatment is transferred to the washing tank 15 while being held by the holding table 12, and the chemical liquid is removed by washing in the washing tank 15.

Thereafter, the semiconductor wafer 11 while being held by the holding table 12 is transferred to a washing buffer tank 16 which is always replaced with newly supplied water, and stored in water.

Subsequently, the semiconductor wafers 11 are gripped one by one from the water in the washing buffer tank 16 by the wafer chuck mechanism 18 and the vertical movement mechanism 19 of the transfer unit 17. That is, the opening / closing chuck 26 is opened vertically downward, and the semiconductor wafer 11 is put into the washing buffer tank 16 so as to grip the side edge portion. Then, the opening / closing chuck 26 is closed and the side edge portion of one semiconductor wafer 11 is gripped. afterwards,
By operating the vertical movement mechanism 19, the wafer chuck mechanism 18 is operated.
Is raised, and the opening / closing chuck 26 holding the semiconductor wafer 11 so that the main surface is vertical is flushed with the washing buffer tank 16.
Get out of

Next, the semiconductor wafer 11 taken out is
The rotation of the rotation arm 25 of the wafer chuck mechanism 18 changes the orientation so that the main surface is horizontal while being held by the opening / closing chuck 26. Then, the wafer chuck mechanism 18 is moved by the horizontal moving mechanism 20 so that the semiconductor wafer 11 is located immediately above the turntable 30 of the rotary drying unit 29.

Subsequently, the wafer chuck mechanism 18 is lowered by the operation of the vertical moving mechanism 19, and the semiconductor wafer 11 is moved.
The open / close chuck 26 is held on the inclined surface of the chuck pin 32 which is open so as to be located on the same circumference as the outer peripheral edge of the semiconductor wafer 11. Thereafter, the crank mechanism 33 is operated so that the chuck pins 32 move toward the center of rotation, and the semiconductor wafer 11 is lifted up along the inclined surface of the chuck pins 32, and the vertical surface of the chuck pins 32 is placed on the outer peripheral edge of the semiconductor wafer 11. Abut,
The semiconductor wafer 11 is supported horizontally.

Then, the turntable 30 is rotated at a high speed, whereby the semiconductor wafer 11 horizontally supported on the upper surface of the turntable 30 is rotated at a high speed, and the semiconductor wafer 11 adheres to the surface of the semiconductor wafer 11 by centrifugal force accompanying the rotation. The semiconductor wafer 11 is dried by shaking off and removing the moisture contained therein.

Thereafter, the operation of the rotary drying unit 29 is stopped, the crank mechanism 33 is operated to open the chuck pins 32, and the semiconductor wafer 11 which has been subjected to the rotary drying by the transfer device is transferred from the rotary table 30 to the next step. Will be sent to

Each of the above steps is performed in the washing buffer tank 1.
The semiconductor wafers 11 stored in the water 6 are picked up one by one by the transfer unit 17 and sequentially executed.

As described above, the semiconductor wafers 11 are taken out of the water in the washing buffer tank 16 stored one by one, and are immediately transferred to the rotary drying unit 29 without waiting for taking out another semiconductor wafer 11. Since rotational drying is performed at a high speed, insufficient drying such as spots due to natural drying does not occur. In addition, since there is no obstacle during rotation drying, drying is promoted and insufficient drying does not occur, static electricity generated during rotation is also suppressed, and adhesion of dust and particles to the semiconductor wafer 11 is reduced.

Further, since the drying is performed one by one, the generation of the watermark is eliminated and the quality can be improved, so that the management of the semiconductor wafers 11 one by one becomes easy.

On the other hand, since the rotary drying is for drying the semiconductor wafers 11 one by one, a large force is not required for the rotation drive, the rotary drying unit 29 is small, and the entire apparatus including the transfer unit 17 is required. Since the space can be reduced and the occupied space can be reduced, the space can be effectively used for installation in a limited place such as a clean room. Incidentally, when the 6-inch semiconductor wafer 11 is dried, the transfer section 17 has a width of 210 mm and a depth of 550 mm, and the rotary drying section 29 has a width of about 250 mm and a depth of about 250 mm, and is installed as shown in the plan view of FIG. In this case, the entire device only needs to have a width of 460 mm and a depth of 550 mm, thereby saving space.

[0037]

As is apparent from the above description, according to the present invention, the semiconductor wafers are picked up one by one by the transfer unit from the buffer tank and transferred to the rotary drying unit. By supporting so as to be substantially horizontal and rotating at a high speed in a horizontal plane to remove water and drying, problems such as poor drying hardly occur and the quality of the drying process can be improved, In addition, effects such as space saving can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view showing a schematic configuration of an embodiment of the present invention.

FIG. 3 is a plan view showing a schematic configuration of a conventional technique.

FIG. 4 is a front view showing a schematic configuration of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Semiconductor wafer 12 ... Holding stand 16 ... Rinse buffer tank 17 ... Transfer part 18 ... Wafer chuck mechanism 19 ... Vertical movement mechanism 20 ... Horizontal movement mechanism 25 ... Rotating arm 26 ... Opening / closing chuck 29 ... Rotary drying part 30 ... Rotating stand 32 ... Chuck pin

Claims (5)

(57) [Claims] 1. A buffer tank for holding semiconductor wafers having been subjected to a water washing process in water, a transfer unit for picking up the semiconductor wafers one by one from the buffer tank and transferring the semiconductor wafers, and A rotary drying unit for supporting the semiconductor wafer so that its main surface is substantially horizontal, and rotating the semiconductor wafer at high speed in a horizontal plane to remove water. 2. The semiconductor wafer according to claim 1, wherein a plurality of semiconductor wafers are subjected to a water washing process in a state where the plurality of semiconductor wafers are mounted on one holding table, and are held in water in a buffer tank while being mounted on the holding table. 2. The apparatus for drying a semiconductor wafer according to claim 1, wherein: 3. The apparatus for drying a semiconductor wafer according to claim 1, wherein the semiconductor wafer is held in a buffer tank so that a main surface thereof is vertical. 4. The transfer section picks up the semiconductor wafer from the buffer tank with the main surface being vertical, changes the semiconductor wafer so that the main surface is horizontal during transfer, and transfers the semiconductor wafer to the rotary drying section. 2. The apparatus for drying a semiconductor wafer according to claim 1, wherein: 5. The apparatus for drying a semiconductor wafer according to claim 1, wherein the rotary drying section supports the semiconductor wafer at a plurality of peripheral positions and rotates the semiconductor wafer in a horizontal plane.