JP2003077988A - Semiconductor wafer mounting method and cassette used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer mounting method handling a thin semiconductor wafer and a cassette used for it. SOLUTION: The wafers W processed thin by finishing background processing are mounted on a support plate 20 in the state that reverses are upward in the cassette C1 and stored in multiple stages in the state that they are sucked and held. The wafers W are taken out to be sucked and held from upward (reverse side of wafer) by an edge ring-like arm 2 from the cassette C1 charged in a mounting device, and consistently handled in the state that the reverses of the wafers W are upward in transferring and mounting them to an alignment stage 4 and transferring and mounting them from the alignment stage 4 to a mounting table 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer mounting method and a cassette used therefor, and more particularly to a technique for handling thin wafers.

[0002]

2. Description of the Related Art Conventionally, a semiconductor wafer to be processed is transported to a mount table (a table for mounting a semiconductor wafer on a ring-shaped frame via an adhesive tape) as follows.

A semiconductor wafer (hereinafter, referred to as "wafer" as appropriate) whose back surface is polished (hereinafter, simply referred to as "back grinding") after pattern formation processing is carried by a carrying mechanism equipped with a robot arm to form a pattern surface. It is stored in multiple stages in a cassette with the face up.

At this time, the cassette Ca as shown in FIG.
Is used. That is, the cassette Ca is provided with the support plate 31 that holds the peripheral portion and the central portion of the wafer.

Then, as shown in FIG. 7, the tip portion 32 of the robot arm for taking out the wafer from the cassette Ca is
A comb-shaped tip 33 is used.

The cassette in which the wafers are stored in multiple stages as described above is transported to the mounting step. Next, in the mounting step, the tip of the robot arm of the transfer mechanism is inserted below the wafer, and the wafer is picked up, sucked and held, taken out, and transferred to the alignment stage.

The wafer, which is placed on the alignment stage with its pattern surface facing upward and has undergone the alignment process, is adsorbed and held by the robot arm from below and is conveyed to the mount table. In this transfer process, the robot arm is rotated and the wafer surface is reversed, that is, the back surface of the wafer is transferred upward and transferred to the mount table.

[0008]

In the present market, semiconductor wafers having a thickness of 200 μm or more are used. However, in recent years, with the demand for high-density mounting of semiconductor wafers,
The thickness of the wafer is 150 to 50 μm, which is less than 200 μm,
It tends to become thinner gradually.

Therefore, when the thickness of the wafer is less than 200 μm, the following problems occur in the current semiconductor wafer mounting method. As the wafer becomes thinner, the rigidity of the wafer against the processing stress remaining after back grinding decreases, so that the distortion of the wafer increases.

When the distortion of the wafer becomes large, when the tip portion of the robot arm is inserted under the wafer and suction-holding by scooping, the suction-holding cannot be performed reliably and a take-out error occurs, or the suction is insufficient. It is taken out as it is. When a wafer that has been taken out with insufficient suction and hold is transferred to each process, for example, when the wafer is turned upside down by rotating the robot arm in the process of being transferred to the mount table, the wafer Problems such as falling will occur.

Further, since the edge of the thinly processed wafer is sharp, if the wafer is stored in the cassette and the peripheral edge (edge) of the wafer hits the wall surface of the cassette during transfer of the cassette, the wafer is The edge may be damaged or the wafer may get stuck in the cassette wall. Further, if the wafer bites into the wall surface of the cassette, problems such as a take-out error when taking out the wafer and damage to the edge may occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor wafer mounting method and a cassette used therefor which can handle a thin semiconductor wafer.

[0013]

The present invention has the following constitution in order to achieve such an object. That is, the invention according to claim 1 is a method of mounting a semiconductor wafer in which a semiconductor wafer is held in a ring-shaped frame via an adhesive tape, wherein a plurality of semiconductors are stored in a cassette with a back surface facing upward. The process of taking out the wafer, transporting it, and aligning it with the back surface facing upward, and transporting the aligned semiconductor wafer, placing it on the mount table with the back surface facing upward, and applying adhesive tape By attaching the semiconductor wafer to the ring-shaped frame via the adhesive tape, the semiconductor wafer is held.

Further, the invention according to claim 2 further comprises:
It is provided with a process of peeling off the protective tape attached to the pattern surface of the semiconductor wafer.

According to a third aspect of the present invention, there is provided a cassette for accommodating a plurality of semiconductor wafers in multiple stages, the cassette having a support portion for mounting the semiconductor wafer with its back surface facing upward. Is.

Further, in the invention described in claim 4, in the cassette described in claim 3, the cassette is provided with a suction means for sucking and holding a semiconductor wafer in a supporting portion.

The present specification also discloses the following solutions.

(1) A semiconductor mounting device which is a transfer mechanism for transferring a semiconductor wafer, and is provided with a suction means for suction-holding a peripheral region of the semiconductor wafer.

According to the invention of (1), since the suction means for sucking and holding the peripheral area is provided, the semiconductor wafer can be sucked and held without bending, and as a result, the semiconductor wafer can be stably held. Can be transported.

[0020]

The operation of the invention described in claim 1 is as follows. That is, since a plurality of semiconductor wafers are stored in a cassette in multiple stages with the back surface facing upward, the semiconductor wafers to be taken out can be sucked and held from above and taken out from the cassette. Also, the semiconductor wafer taken out is
Since the alignment is done with the back side facing up,
The back surface of the semiconductor wafer is always directed upward until it is transported to the mount table. That is,
The semiconductor wafer transfer mechanism of the conventional apparatus has a reversing mechanism for reversing the semiconductor wafer, but this mechanism is not necessary. Therefore, the semiconductor wafer is prevented from dropping when the semiconductor wafer is turned over.

According to the second aspect of the invention, the semiconductor wafer and the ring-shaped frame are integrated with each other via the adhesive tape on the mount table, and the semiconductor wafer and the ring-shaped frame are protected from the surface (pattern surface) of the dispensed semiconductor wafer. The tape is peeled off.

According to the third aspect of the invention, it is possible to store the semiconductor wafers in multiple stages in the cassette with the back surface facing upward. That is, the method of claim 1 can be preferably realized.

Further, according to the invention of claim 4,
Since the semiconductor wafer placed on the supporting portion is sucked and held, the semiconductor wafer is held in a stable state without moving in the cassette.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a semiconductor wafer (hereinafter, simply referred to as “wafer”) mounting device of the present invention, and FIG. 2 is a diagram of a cassette for accommodating wafers in multiple stages.

This semiconductor wafer mounting apparatus includes a wafer supply unit 1 in which a cassette C1 in which a plurality of wafers W subjected to back grinding processing are stored is loaded, a wafer transfer mechanism 3 equipped with a first robot arm 2, and a wafer. Alignment stage 4 for aligning W, alignment stage 5 for aligning frame f, which is a ring-shaped frame, mount table 6 for mounting frame f and wafer W, adhesive tape T for supplying to mount table 6 Part 7, a tape collecting part 8 for collecting the residual tape after the adhesive tape T is attached, a transfer mechanism 10 equipped with a second robot arm 9 for transferring the mount frame F in which the wafer W and the frame f are integrated, and a pattern The peeling site 11 for peeling off the protective tape P attached to the surface and the peeling tape Tp Place tape supply unit 1 for supplying to 11
2, a tape collecting unit 14 that winds and collects the peeled and processed peeling tape Tp, a character recognition unit 15 that reads the serial number of the processed wafer W, a printer 16 that attaches a barcode label to the mount frame F, and a mount A mount frame recovery unit 17 in which the cassettes C2 for accommodating the frames F in multiple stages are loaded is provided on the upper portion of the base 18.

Here, the wafer supply unit 1, the wafer transfer mechanism 3, the alignment stages 4 and 5, the mount table 6, the wafer transfer mechanism 10, the peeling portion 11, and the character recognition unit 1 are provided.
5, the printer 15, and the wafer recovery unit 17 are the base 18
On the other hand, the tape supply unit 7 and the tape recovery unit 8 which are composed of a tape attaching unit
The mount table 6 is slidably arranged on a member (not shown) so as to straddle the mount table 6. Further, a tape supply unit 12 for supplying the peeling tape Tp and a tape recovery unit 14 are provided on the front surface of a vertical wall (not shown) standing on the upper surface of the base 12.

The wafer supply unit 1 places a wafer W in a horizontal position with the surface on which the protective tape P is attached facing downward, that is, the back surface facing upward, on a support plate 20 provided at each stage of the cassette C1, A cassette C1 in which a plurality of these wafers W are stored in multiple stages is loaded on a cassette table. The cassette base can be rotated by an air cylinder (not shown) to change its direction.

The cassette C1 has the characteristic structure of this embodiment. Hereinafter, a more specific description will be given with reference to FIGS. 2 and 3. The cassette C1 has a flat plate shape that is substantially the same as the internal area of the cassette C1 so that the wafer W whose pattern surface is protected by the protective tape P can be placed with the pattern surface facing downward. The support plates 20 are provided in multiple stages. A suction hole 21 for vacuum-sucking and holding the wafer W is provided in the center of the support plate 20. The suction hole 21 is connected to a solenoid valve 23 via a pipe 22 inside the support plate 20.

A solenoid valve 23 is provided on each support plate 20, and an air joint 24 is provided from the top of the cassette C1.
It is connected to the vacuum source 25 via. Air joint 2
For example, one that can be attached / detached with one touch is used as 4. Further, on the rear side surface of the cassette C1, the connectors 26 corresponding to the number of storage stages of the wafer W, that is, the number of the support plates 20 are provided.
Is provided. This connector 26 is for each stage of the solenoid valve 2
It is for transmitting a signal for controlling 3 independently.

That is, the wafer W placed on the support plate 20 at an arbitrary position is placed on the support plate 20, and at the same time, the electromagnetic valve 23 is opened (turned on) to cause the suction holes 2
It is adapted to be held by suction. Further, when the cassette C1 is removed from the apparatus for storing the wafer W, the electromagnetic valve 23 is first closed, then the wiring (for control signal transmission) connected to the connector 26 is removed, and the vacuum source 25 is removed from the air joint 24. Then, the cassette C1 can be freely moved.

Since the wafer W seals the suction hole 21, the electromagnetic valve 23 is turned off for a certain period of time.
The vacuum suction state is maintained and the wafer W is stably held.

When the wafer W is stored in the cassette C1 for a long time, the vacuum source 25 provided at the storage location is connected to the air joint 24, and the solenoid valve 23 at the required location is opened ( When turned on, the wafer W accommodated and held can be escaped from the careless vibration applied to the cassette C1. The support plate 20 and the suction holes 21 correspond to the support portion of the present invention.

Next, the first robot arm 2 of the transfer mechanism 3
As shown in FIG. 4, the tip 27 has a ring shape, and a plurality of suction holes 28 are formed along the circumference of the center of the ring.
Is provided. That is, when the tip portion 27 abuts on the wafer W, the wafer W is sandwiched between the tip portion 27 and the support plate 20, the distortion of the wafer W is corrected, and the tip portion 27 circles the wafer W. The peripheral area is vacuum-adsorbed and held.

Further, the first robot arm 2 is constructed so as to be capable of moving horizontally and horizontally, and the front end portion 27 is inserted into the wafer supply portion 1, and the upper side of the wafer W, that is, the rear surface is sucked and held and taken out, and the alignment stage 4 is arranged. Supply of the wafer W to the
The wafer W is supplied from the alignment stage 4 to the mount table 6. At this time, the wafer W is sandwiched between the support portion (not shown) of the alignment stage 4 and the tip portion 27.
The distortion of is corrected.

On the mount table 6, the frame f subjected to the alignment processing by the alignment stage 5 is carried and held by the movable table, and the wafer W placed on the predetermined position and posture by the first robot arm 2 is placed. It is designed to be adsorbed and held.

The tape supply unit 12 is composed of a tape attaching unit which passes the adhesive tape T drawn from the original roll over the mount table 6, and a cutter mechanism K which cuts the adhesive tape. The tape recovery unit 8 also includes a tape recovery unit 8 for recovering the cut residual tape.

The second robot arm 9 is constructed so that it can be moved forward and backward and swung horizontally. By attaching an adhesive tape to the mount table 6, the mount frame F in which the wafer W and the frame f are integrated is sucked and held, and the pattern surface is formed. The mount frame F is turned upside down by turning the arm so as to face upward, and the mount frame F is carried into the peeling table.

The tape supply unit 12 is adapted to supply the peeling tape Tp drawn from the original roll through the upper side of the peeling table. That is, the peeling roller R2 rolls on the surface of the protective tape P attached to the pattern surface of the wafer W to attach the peeling tape Tp, and the peeling tape Tp and the protective tape P are integrally peeled. Is configured. The peeling tape Tp is the wafer W.
The narrower than the diameter of is used.

The character recognition section 15 is composed of a CCD for reading characters such as a serial number stamped on the wafer W and a computer for analyzing the read characters.

The printer 16 converts the manufacturing control number into a bar code according to the character recognized by the character recognition unit 15,
A bar code label is printed out and attached to the mount frame F.

The mount frame recovery unit 17 inserts and stores the mount frame F, to which the protective tape has been peeled off and the bar code is affixed, into the cassette C2 with an appropriate space above and below it, and It is designed to be loaded on top. This cassette stand can also be turned by an air cylinder (not shown) to change its direction.

The basic steps of the apparatus of the above embodiment will be described below with reference to FIG. First, the front end of the first robot arm 2 is inserted into the gap of the cassette C1 of the wafer supply unit 1, one backside wafer W is adsorbed and held from above, and is taken out and placed on the alignment stage 4. . Here, the alignment of the wafer W is performed based on the detection of the orientation flat or the notch of the wafer W. The wafer W that has been aligned is again suction-held on the back surface by the first robot arm 2 and transferred to the mount table 6.

The mount table 6 has a frame chuck portion (not shown). Then, the aligned frame f is supplied from the alignment stage 5 to the frame chuck portion and suction-held. At this time,
The wafer W is placed on the mount table 6 in a predetermined posture and position, and is suction-held. At this time, the sticking roller R1 for the adhesive tape T is at the standby position behind the frame f.

Next, the sticking roller R1 rolls on the wafer W and the frame f to stick the adhesive tape T thereon. Then, the adhesive tape T is cut into a circle on the frame by the cutter mechanism K, and the residual tape after cutting is collected by the tape collecting unit 8.

The mount frame F in which the adhesive tape T is attached and the frame f and the wafer W are integrated is ejected from the mount table 6, sucked and held by the second robot arm 9, and conveyed to the peeling table. During this transfer process, the second robot arm 9 turns and the wafer W
The pattern surface of is turned up.

The wafer W transferred to the peeling table is placed on a suction pad (not shown) in a predetermined posture and position, and is held by suction with the pattern surface to which the protective tape P is attached facing upward. At this time, the peeling roller R
2 is at a standby position apart from the peeling table.

When the mount frame F is loaded on the peeling table, the peeling roller R2 rolls on the wafer W to stick the peeling tape Tp on the surface of the protective tape P and to be integrated with the protective tape P. The peeling tape Tp adhered to is peeled from the surface of the wafer W. At this time, the peeling tape Tp is timely supplied from the tape supply unit 12, and the protective tape P peeled together with the peeling tape Tp is collected by the tape collecting unit 14.

The wafer W from which the protective tape P has been removed by the peeling tape Tp is transferred to the character recognition unit 1 by the carrier.
5, the manufacturing number is printed on the wafer W, and the recognition process is performed. Then, the printer 16 affixes the label of the manufacturing control number, which is newly bar-coded, to the mount frame F.

The mount frame F, to which the bar code label is attached, is carried by the carrying table and inserted into the cassette C2 for storage.

The structure of the mounting process is not limited to the structure of the above embodiment.

As described above, the backgrinded wafer W is sucked and held by being sandwiched between the tip portion 27 and the support plate 20.
The distortion generated in the wafer W is prevented, and by extension, the tip portion 27
Thus, the wafer W can be surely sucked and held, and the stable transfer of the wafer W can be realized.

Further, the supporting plate 20 covering the whole area of the wafer W and the suction holes 21 provided in the supporting plate 20.
By sucking the wafer W in vacuum, the wafer W can be stably held in the cassette C1 even when the cassette C1 is moved.

Further, the wafer W housed in the cassette C1 with the back surface facing upward is sucked and held from above (the back surface) the wafer W by the first robot arm 2 having the ring-shaped tip 27, When the wafer W is handled with the back surface facing upward in all of the supply to the alignment stage 4, the alignment, and the transfer to the mount table 6 after the alignment processing, it is possible to avoid the wafer W from being dropped due to being inverted.

The present invention is not limited to the above embodiment, but can be modified as follows.

(1) In the above embodiment, one wafer W is sucked and held by the tip of the first robot arm 2 and taken out from the cassette C1. At this time, the wafer W is provided on the support plate of the wafer W of the cassette C1. Alternatively, air may be supplied from the suction holes to support suction holding by the first robot arm 2.

(2) The support plate 20 of the cassette C1 in the above embodiment is designed to hold the entire area of the wafer W, but the present invention is not limited to this form, and for example, as shown in FIG. In addition, it is possible to use a wafer W that is lightened by providing an opening H in the center thereof so that the wafer W does not bend when it is placed on the support plate.

(3) In the above embodiment, the tip end portion 27 of the first robot arm 2 has a ring shape and a plurality of suction holes 28 are provided, but it is not limited to the above embodiment. Instead, it is sufficient if the wafer W can be transported in a stable state without being bent during suction and transportation.

[0058]

As is apparent from the above description, according to the first aspect of the present invention, the wafers stored in the cassette in multiple stages are arranged from above with the back surface opposite to the pattern surface facing upward. By adsorbing and holding and taking out, and by aligning with the back side facing up,
Until the wafer is placed on the mount table, the wafer can be always handled with the back surface facing upward. As a result, it is possible to prevent the wafer from dropping when the wafer is turned over during the transfer process.

According to the second aspect of the present invention, the protective tape attached to the pattern surface of the wafer can be peeled off.

According to the third aspect of the present invention, since the back surface of the wafer can be stored in multiple stages with the back surface facing upward, the wafer can be adsorbed and taken out from above the wafer. At this time, since the wafer is sandwiched between the support portion and the tip of the arm, the distortion of the wafer can be corrected and the wafer can be taken out from the cassette. That is, the method of claim 1 can be preferably realized.

Further, according to the invention described in claim 4,
Since the wafer can be held on the supporting portion by the suction means, the wafer can be held in a stable state without moving in the cassette.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a semiconductor wafer mounting apparatus according to an embodiment.

FIG. 2 is a partially cutaway perspective view of a cassette used in the apparatus of this embodiment.

FIG. 3 is a diagram showing a main configuration of a cassette.

FIG. 4 is a diagram showing a tip portion of a robot arm according to an embodiment.

FIG. 5 is a perspective view of a modified cassette.

FIG. 6 is a perspective view of a conventional cassette.

FIG. 7 is a view of a tip portion of a conventional robot-arm.

[Explanation of symbols]

1 ... Wafer supply unit 2 ... 1st robot arm 3 ... Wafer transfer mechanism 4… Alignment stage 6… Mount table 20 ... Support plate 21 ... Adsorption hole 22 ... Tube 23 ... Solenoid valve 24 ... Air fitting 25 ... Vacuum source 26 ... Connector 27 ... Robot arm tip 28 ... Adsorption hole C1 ... cassette f ... Frame (ring frame) F ... Mount frame W ... Semiconductor wafer

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Claims (4)

[Claims] 1. A method of mounting a semiconductor wafer in which a semiconductor wafer is held on a ring-shaped frame via an adhesive tape, wherein a plurality of semiconductor wafers stored in a cassette are taken out and conveyed with the back side facing upward. , A process of aligning with the back surface facing upward, and carrying the aligned semiconductor wafer, placing the semiconductor wafer on the mount table with the back surface facing upward, and adhering the adhesive tape to the adhesive tape. And a step of holding the semiconductor wafer on the ring-shaped frame via the. 2. The method of mounting a semiconductor wafer according to claim 1, further comprising a step of peeling off a protective tape attached to a pattern surface of the semiconductor wafer. 3. A cassette for accommodating a plurality of semiconductor wafers in multiple stages, wherein the cassette includes a supporting portion for mounting the semiconductor wafer with the back surface of the semiconductor wafer facing upward. 4. The cassette according to claim 3, wherein the cassette is provided with suction means for sucking and holding a semiconductor wafer in a supporting portion.