JP2001308048A - Method of cleaning and carrying ground wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent polishing chips or abrasive grains from sticking to the surface of a chuck which vacuum-chucks a wafer. SOLUTION: A polished wafer is carried to the next process via the following processes. (1) A scrub washer 209a is shifted to a position above a wafer to be polished, vacuum-chucked by a chuck 107, and a wafer-polishing face is cleaned by brush scrubbing by rotating a brush, while supplying cleaning water onto a wafer face by nozzle 211, and polishing chips and abrasive grains are washed away. (2) The supply of cleaning liquid is stopped, and the scrub washer 209a is lifted, and then the rinse water of a quantity (0.5-3 liters/min. with a wafer, for example, 200 mm or 30 mm in diameter) that a water layer is made on the surface of the water is supplied by rinse water supply pipe 209c. (3) The wafer is carried to the next process (for example, accommodation in a storage cassette, etching, and polishing) by suction pad, after chucking the wafer by rotating the suction pad 112a of a carriage mechanism 112 onto the topside of the wafer cleaned and rinsed, while continuing the supply of the rinsing water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a next step of cleaning a wafer which has been ground and cleaned without grinding debris or abrasive grains on the surface of the ground wafer, for example, a step of storing a wafer in a storage cassette, or The present invention relates to a method of transporting the wafer to an etching step or a polishing step.

[0002]

2. Description of the Related Art In order to reduce the grinding time of a wafer, a plurality of grinding wheels mounted on a plurality of spindles are used as a back grinding device for a device wafer. The throughput time is shortened. For example, Japanese Patent Laying-Open No. 11-307489 discloses a grinding apparatus using an index table.

The etching mechanism 20 shown in FIGS. 4 and 5
In the grinding apparatus 1 to which a wafer loading cassette 101 is attached, (A) a wafer loading cassette 11 is provided on the left side.
7 on the right side, and a wafer unloading cassette 117
Are arranged in the front row as a pair, and (B) the wafer row is placed on the base.
A temporary wafer mounting table 106 is arranged at the rear of the loading cassette, and a wafer cleaning mechanism 113 is arranged at the rear of the wafer unloading cassette in the next row. An index turntable is provided in the hollowed out area, and this index turntable
The table 108 is provided with three wafer chuck mechanisms 107, 107, 107 which are revolvable at equal intervals around the axis of the table, and includes a wafer loading / wafer unloading zone s1 and a coarse grinding zone. (D) The table is divided into finishing grinding zones s3, and (D) a grinding wheel suitable for each grinding zone is provided on a frame 111 standing upright from the base in the rear row of the index turntable. 111b, 11
A grinding mechanism having 1d supported on spindle shafts 111a and 111c is provided corresponding to a wafer chuck mechanism located in each grinding zone. (E) The front row of the pair of cassettes, the temporary mounting table, and the wafer cleaning mechanism. An articulated robot 115 having an elevating mechanism 103, a rotary drive mechanism, a wafer alignment measuring mechanism, and a control mechanism for driving the respective arms 115a, 115b, 115c is erected substantially at the center of the base between the next rows. The wafer on the temporary table can be transferred to a chuck mechanism of a wafer loading / wafer unloading zone s1 of an index turntable, and the wafer on a cleaning mechanism can be transferred to a wafer unloading cassette. The articulated robot 115 is rotated about a pair of shafts provided on the left and right at substantially the center of a base provided with an index turntable (F). A transfer pad 112 for transferring a wafer from a temporary mounting table having a freely provided wafer suction pad 112a to a chuck mechanism of a wafer loading / wafer unloading zone, and a wafer loading / wafer unloading zone on the chuck mechanism. (G) a cleaning mechanism 109b of a chuck mechanism and a dresser 109a of a chuck mechanism capable of moving in the left-right direction on a screw bar provided on a frame body 110 erected from a base, (G). Have a pair.

The above-mentioned grinding device 101 (however, chuck mechanisms provided on the index turntable are a, b, c
M = 3 groups. ), The following steps are used to grind the wafer.

(1) Robot 115 provided on a base
The wafer is sucked from the wafer loading cassette 117 to the suction arm and is placed on the temporary mounting table 106. (2) The index turntable 118 is rotated 120 degrees, and then the wafer on the temporary table is transferred to the transfer pad 11.
The wafer is transferred to the chuck mechanism a of the wafer loading / wafer unloading zone S1 of the index turntable by rotating the transfer pad.
In the meantime, the wafer is sucked from the wafer loading cassette to the suction arm of the robot,
06.

(3) Index turntable 11
After rotating the chuck mechanism a to the coarse grinding zone S2 and the chuck mechanism b to the wafer loading / wafer unloading zone S1, the first spindle shaft 111a is lowered. Whetstone 111
b is pressed against the wafer, and the chuck mechanism a and the first spindle shaft are rotated to roughly grind the wafer.
The first spindle shaft is raised, and during this time, the wafer on the temporary table is transferred to the chuck mechanism b of the wafer loading / wafer unloading zone S1 of the index turntable by the transfer pad 112, and the robot 115 The wafer in the wafer loading cassette is placed on the temporary mounting table by using.

(4) The index turntable is set to 1
Rotate by 20 degrees and place chuck mechanism a on finish grinding zone S3.
After moving the chuck mechanism b to the coarse grinding zone S2 and the chuck mechanism c to the wafer loading / wafer unloading zone S1, the second spindle shaft 111c is lowered to remove the grindstone 111d. The wafer is pressed and the chuck mechanism a and the spindle shaft are rotated to finish grind the wafer. Then, the second spindle shaft is raised, and during this time, the first spindle shaft is lowered to move the grindstone to the wafer. Is pressed to rotate the chuck mechanism b and the spindle shaft to roughly grind the wafer. Then, the first spindle shaft is raised, and the wafer on the temporary mounting table is indexed by a transfer pad. -Loading / wafer unloading zone-
To the chuck mechanism c of the
The wafer in the wafer loading cassette is placed on the temporary mounting table by using 15.

(5) The index turntable is set to 1
By rotating the chuck mechanism 20 degrees, the chuck mechanism a is moved to the wafer loading / wafer unloading zone S1, the chuck mechanism b is moved to the finish grinding zone S3, and the chuck mechanism c is moved to the rough grinding zone S2. The finish-ground wafer is transferred to the cleaning mechanism 113 by the transfer pad 112, and the wafer is cleaned. Then, the arm of the robot 25 in the etching mechanism 20 attracts the finished-ground and cleaned wafer, and is etched. The wafer is placed on a spinner 26 of the mechanism, and the surface of the wafer is etched, cleaned, and rinsed.
The rinsed wafer is sucked by the suction arm of the robot 25 and stored in the unloading cassette 24.
Next, the transport pad 112 is rotated so that the
The upper wafer is indexed into a wafer table.
To the chuck mechanism a of the loading / wafer unloading zone, while the suction arm of the robot 115
The wafer is sucked from the wafer loading cassette onto the temporary mounting table, and the second spindle shaft is lowered to press the grindstone against the wafer while rotating the chuck mechanism b and the spindle shaft. Finish grinding of the wafer is performed, then the second spindle shaft is raised, and the first spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism c and the spindle shaft are rotated to rotate the wafer. Rough grinding is performed, and then the first spindle shaft is raised.

(6) One index turntable
The chuck mechanism b is rotated by 20 degrees, the chuck mechanism b is used as a wafer loading / wafer unloading zone, the chuck mechanism c is used as a finish grinding zone, and the chuck mechanism a is used as a rough grinding zone.
The wafer is then transferred to a cleaning mechanism, and the robot is cleaned.
The finished grinding and washed wafer is adsorbed on the arm, and the wafer is placed on a spinner 26 of an etching mechanism, and the wafer surface is etched, washed and rinsed. The rinsed wafer is sucked by the suction arm of the robot 25 and stored in the unloading cassette 24. Then
By rotating the transfer pad 112, the wafer on the temporary table 106 is loaded into an index turntable.
The wafer is transferred to a chuck mechanism b of a wafer unloading zone, and a wafer is suctioned from a wafer loading cassette to a suction arm of the robot, and the wafer is placed on a temporary mounting table. Is lowered to press the grindstone against the wafer, the chuck mechanism c and the spindle shaft are rotated to finish grind the wafer, and then the second spindle shaft is raised, and
The second spindle is lowered to press the grindstone against the wafer, and the chuck mechanism a and the spindle are rotated to roughly grind the wafer, and then the first spindle is raised.

(7) The index turntable is set to 1
By rotating the chuck mechanism 20 degrees, the chuck mechanism c becomes a wafer loading / wafer unloading zone, the chuck mechanism a becomes a finish grinding zone, and the chuck mechanism b becomes a rough grinding zone.
Then, the wafer that has been finish-ground by the transfer pad is transferred to a cleaning mechanism, and the wafer is cleaned and rinsed. The arm of the robot 25 attracts the wafer that has been finish-ground and cleaned, and is etched. Put on the spinner 26 of the mechanism,
Etching, cleaning and rinsing of the wafer surface. The rinsed wafer is sucked by the suction arm of the robot 25 and stored in the unloading cassette 24.
Then, the transfer pad is rotated to transfer the wafer on the temporary table to the chuck mechanism c of the wafer loading / unloading zone of the index turntable.
On the other hand, the wafer arm is attached to the suction arm of the robot 115.
The wafer is sucked from the loading cassette and placed on a temporary mounting table, during which the second spindle shaft is lowered to press the grindstone against the wafer, and the chuck mechanism a and the spindle shaft are rotated to finish grind the wafer. And then raise the second spindle shaft, and
The second spindle is lowered to press the grindstone against the wafer, and the chuck mechanism b and the spindle are rotated to roughly grind the wafer, and then the first spindle is raised.

(8) Hereinafter, the rotation of the index turntable, the finish grinding and cleaning of the coarsely ground wafer, the etching of the wafer, and the unlocking of the etched wafer.
Steps (5) to (7) of storing in a loading cassette, transferring a new wafer to a wafer loading / unloading zone to a chuck mechanism, and rough grinding of a wafer are repeated. The cleaning mechanism 109b of the chuck mechanism
And a dresser 109a of the chuck mechanism can move up and down and move in the left-right direction. When the temporary table is empty with no wafer, the dresser 109a cleans or dresses the chuck.

In FIG. 4, reference numeral 21 denotes a shutter mechanism provided on a partition wall of the grinding apparatus 101 and the etching mechanism 20 for opening and closing an opening for transferring a wafer. 35 is a shutter mechanism. A polishing mechanism may be used instead of the etching mechanism (see Japanese Patent Application No. 11-111250).

In the conventional grinding device, the cleaned wafer is cleaned by the grinding device 101 after the grinding.
The wafer was transferred to the cleaning mechanism 113, where cleaning and rinsing were performed. However, the surface of the wafer dries while the wafer ground by the chuck is transferred, and grinding debris and solids in the grinding fluid adhere to the wafer surface, and the cleaning mechanism 113 removes these solids from the wafer surface. Or the surface of the chuck dries while the similarly ground wafer is transferred from the chuck to the next process (cleaning, etching, polishing or unloading, etc.)
Grinding debris and solids in the grinding fluid adhere to the chuck surface, making cleaning and dressing of the chuck difficult, and causing scratches on the wafer.

In particular, adhesion of such solid matter is considered to be a problem in grinding the back surface of a wafer on which a device pattern is provided, and it is proposed to brush-scrub the wafer on a chuck provided on an index table. Kaihei 10-172
No. 932). That is, the cleaning mechanism 113 in FIG. 4 is eliminated, and the cleaning mechanism 109b of the chuck mechanism and the dresser 109a of the chuck mechanism are used.
Is a grinding apparatus 201 in which a cleaning mechanism 209b of a chuck mechanism and a wafer scrub cleaning mechanism 209a are replaced. In such a grinding apparatus 201, the ground wafer on the chuck is cleaned and transported as follows.

(1) A rotatable brush and a cleaning liquid are applied to a brush surface of a wafer, which is vacuum-chucked on a gas-permeable disk-shaped base (chuck) supported on a rotatable hollow shaft. A scrub cleaning device 209a having a nozzle for supply is lowered to press a rotating brush on the wafer surface, and to brush scrub the wafer surface while spraying a cleaning liquid from the nozzle on the wafer surface. (2) The brush-scrub-cleaned wafer is put on the suction pad 1
The wafer 12 is rotated to move the wafer, and after the wafer is sucked, the wafer is transferred to the next step by the suction pad.

[0016]

In the above-mentioned scrub cleaning, supply of the cleaning liquid is stopped after cleaning the ground surface of the wafer.
The cleaning device 209a is raised and moved to the left and right, and then the wafer is transferred to the next step by the suction pad. Therefore, there is an opportunity for the above-mentioned solid matter to adhere to the wafer surface and the chuck surface during the lifting of the scrub cleaning device 209a, the movement to the left and right, and the rotation of the suction pad 112.

The adhesion of solids on the wafer surface can be prevented by extending the scrub cleaning time. However, adhesion of solids on the chuck surface cannot be prevented, making chuck cleaning difficult. The present invention prevents the chuck and wafer surface from drying while the ground wafer is transferred from the chuck to the next process (cleaning, etching, polishing or unloading, etc.), and removes grinding chips and grinding fluid from the wafer surface. It is an object of the present invention to provide a method for transferring a ground wafer to which no solid matter adheres.

[0018]

According to a first aspect of the present invention, there is provided a method of cleaning a wafer ground by a grinding apparatus and transferring the wafer to a next step, wherein the method includes the following steps (1) to (4). And a method of cleaning and transporting a wafer. (1) Vacuum chucking is performed on a disk-shaped table having air permeability and water permeability supported on a rotatable hollow shaft with the ground surface of the ground wafer facing upward. (2) A scrub cleaning device having a rotatable brush and a nozzle for supplying a cleaning liquid to the brush surface is lowered to press the rotating brush onto the wafer surface, and to brush the wafer surface while spraying the cleaning liquid from the nozzle onto the wafer surface. Scrub clean.

(3) After the supply of the cleaning liquid is stopped and the scrub cleaning equipment is raised, or after the scrub cleaning equipment is raised and the supply of the cleaning liquid is stopped, a water film is formed on the wafer surface from the rinse water supply pipe. Depressurization of the vacuum chuck is stopped while supplying as much rinsing water as possible, and pressurized water is supplied from the hollow shaft to the back surface of the wafer, thereby facilitating separation of the wafer from the chuck. (4) While continuing to supply the rinsing water, the suction pad of the transfer mechanism is rotated and moved to the upper surface of the washed and rinsed wafer, and the wafer having the water film formed on the surface is sucked. The wafer is transferred to the next step by the suction pad.

When the ground wafer is transferred, the surface of the wafer and the surface of the chuck-shaped disk-shaped table (chuck) are wet with the rinsing water, so that adhesion of solids can be prevented. When the wafer is removed from above the chuck, the chuck cleaning device 209b cleans the wet chuck surface, so that foreign matter does not adhere to the chuck surface.

According to a second aspect of the present invention, in the above-mentioned cleaning / transporting method, the scrub cleaning device and the chuck cleaning device are arranged so as to be paired on the left and right sides of the rinse water supply tube, and the scrub cleaning device, the rinse water supply tube and The chuck cleaning device is integrally provided so as to be horizontally movable on a plane parallel to the surface of the disk-shaped base.

The grinding device becomes compact.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a partial plan view showing an example of a grinding device used for carrying out the present invention, FIG. 2 is a side view of the grinding device, and FIG. 3 is a diagram showing a scrub cleaning device, a chuck cleaning device and a rinse water supply pipe of the grinding device. FIG. 3 is an enlarged view of FIG. 2 showing a portion.

The grinding apparatus 20 shown in FIGS. 1, 2 and 3
In FIG. 1, 107a, 107b and 107c are chucks, 108 is an index table, 111a is a first spindle axis, 111c is a second spindle axis, 112 is a transport pad, 112a is a suction pad, 112b is a rotary axis,
112c is an air tube, 209a is a scrub cleaning device, 20
9b is a chuck cleaning device, 209c is a rinse water supply pipe,
210 is a brush, 211 is a washing water spout, 212 is a ceramic dresser, 213 is an air cylinder for raising and lowering the scrub cleaning equipment, 214 is an air cylinder for raising and lowering the chuck cleaning equipment, 215 is a fixing plate for the rinse water supply pipe,
216 is a hose. The scrub cleaning device 209a and the chuck cleaning device 209b are arranged so as to form a pair on the left and right sides of the rinse water supply pipe 209c. Are provided so as to be able to move horizontally on a plane parallel to.

Reference numeral 217 denotes a rail, a scrub cleaning device,
It is used to move the rinse water supply pipe and the chuck cleaning device together in the horizontal direction. 218 is a plastic chain
It is. 219 and 220 are two-point in-process gages (wafer thickness measuring devices).

The cleaning and transfer of the wafer vacuum-adsorbed to the chuck 107 of the second grinding zone S3, which has been ground by the grinding device 201, is performed through the following steps. (1) The index table 108 is rotated, and the chuck 107 of the second grinding zone S3 is loaded / wafer-loaded.
Move to unloading / scrub cleaning zone S1. (2) A scrub cleaning device 209a is mounted on the rail 217 at a position above the vacuum-adsorbed ground wafer in the zone S1.
Then, the brush 211 of the scrub cleaning device is lowered until the brush 211 of the scrub cleaning device comes into contact with the surface of the wafer.
The brush is rotated while supplying the wafer to the wafer surface, and the wafer grinding surface is scrubbed with a brush to wash away grinding dust and abrasive grains. During this time, the chuck is rotating. The brush may be rotated and the scrub cleaning device may be lowered while supplying cleaning water to bring the brush into contact with the wafer surface. (3) The supply of the cleaning liquid is stopped, and the scrub cleaning device 209a is used.
After raising, or raising the scrub cleaning equipment,
After the supply of the cleaning liquid is stopped, the rinse water supply pipe 20
9c, the amount of water film formed on the wafer surface (for example,
The vacuum pressure of the vacuum chuck is stopped while rinsing water (0.5 to 3 liters / minute for a 0 mm or 300 mm wafer) is supplied, and pressurized water is supplied to the back surface of the wafer from the hollow shaft to facilitate wafer separation from the chuck. I do. (4) While continuing to supply the rinsing water, the suction pad 112 of the transfer mechanism 112 is placed on the upper surface of the cleaned and rinsed wafer.
After the wafer is sucked, the wafer is conveyed to the next step (for example, storage cassette, etching, polishing) by the suction pad.

When the wafer is conveyed and the chuck on the S1 zone is emptied, the chuck cleaning device 209b is moved to the rail 2
17, the chuck ceramic is lowered until the annular ceramic 212 of the chuck cleaning device comes into contact with the wafer surface, the ceramic is rotated while cleaning water is supplied to the wafer surface, and the chuck surface is cleaned to remove grinding chips and abrasive grains. Wash off.
During this time, the chuck is rotating.

[0028]

According to the method of cleaning and carrying a ground wafer of the present invention, the wafer surface is rinsed with rinsing water even when the wafer is carried to the next step, and the surface of the chuck is removed when the wafer is removed from the chuck. Since the rinsing water is supplied to the chuck surface and the chuck surface is wetted, it does not happen that grinding dust and abrasive grains are dried and adhered to the chuck surface.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a grinding device.

FIG. 2 is a side view of the grinding device of FIG.

FIG. 3 is a partially enlarged view of FIG. 1;

FIG. 4 is a partial plan view of a grinding device provided with an etching mechanism.

FIG. 5 is a perspective view of a known grinding device.

[Explanation of symbols]

 101 Grinding device 201 Grinding device 107 Chuck 108 Index table 111a, 111c Spindle shaft 111b, 111d Grinding wheel 112 Transfer mechanism 112a Suction pad 209a Brush scrub cleaning device 209b Chuck cleaning device 209c Rinse water supply pipe

Claims (2)

[Claims] 1. A method of cleaning and transporting a wafer ground by a grinding device and transporting the wafer to the next step, wherein the method includes the following steps: (1) a rotatable hollow shaft Vacuum chucking is performed on the disc-shaped base having air permeability and water permeability, with the ground surface of the ground wafer facing upward. (2) A scrub cleaning device having a rotatable brush and a nozzle for supplying a cleaning liquid to the brush surface is lowered to press the rotating brush onto the wafer surface, and to brush the wafer surface while spraying the cleaning liquid from the nozzle onto the wafer surface. Scrub clean. (3) After the supply of the cleaning liquid is stopped and the scrub cleaning equipment is raised, or after the scrub cleaning equipment is raised and the supply of the cleaning liquid is stopped, the amount of a water film formed on the wafer surface from the rinse water supply pipe is reduced. Depressurization of the vacuum chuck is stopped while rinsing water is being supplied, and pressurized water is supplied to the back surface of the wafer from the hollow shaft to facilitate the separation of the wafer from the chuck. (4) While continuing to supply the rinsing water, the suction pad of the transfer mechanism is rotated and moved to the upper surface of the cleaned / rinsed wafer to remove the rinsed / rinsed wafer having a water film formed on the surface. The suction pad of the transfer mechanism is rotated and moved to the upper surface, and after the wafer is sucked, the wafer is transferred to the next step by the suction pad. 2. A scrub cleaning device and a chuck cleaning device are arranged so as to form a pair on the left and right sides of a rinse water supply pipe, and the scrub cleaning device, the rinse water supply pipe and the chuck cleaning device are integrally parallel to the surface of the disk-shaped base. 2. The method for cleaning and transporting a wafer according to claim 1, wherein the method is provided so as to be horizontally movable on a flat surface.