JP4748901B2 - Semiconductor wafer mounting method and cassette used therefor - Google Patents

Description

[0001]
BACKGROUND 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 a thin wafer.
[0002]
[Prior art]
Conventionally, a semiconductor wafer to be processed is transferred to a mount table (a table for mounting a semiconductor wafer on a ring-shaped frame via an adhesive tape) as follows.
[0003]
A semiconductor wafer (hereinafter referred to as “wafer” where appropriate) whose surface has been subjected to pattern formation and whose back surface has been polished (hereinafter simply referred to as “back grind”) is transported by a transport mechanism having a robot arm, with the pattern surface facing upward. In this state, it is stored in multiple stages in the cassette.
[0004]
At this time, a cassette Ca as shown in FIG. 6 is used. That is, the cassette Ca is provided with the support plate 31 that holds the peripheral edge and the center of the wafer.
[0005]
The tip 32 of the robot arm that picks up the wafer from the cassette Ca has a comb-like tip 33 as shown in FIG.
[0006]
Thus, the cassette in which the wafers are stored in a plurality of stages is transferred to the mounting process. Next, in the mounting process, the tip of the robot arm of the transfer mechanism is inserted below the wafer, and the wafer is scooped up, held by suction, taken out, and transferred to the alignment stage.
[0007]
The wafer on which the pattern surface is placed on the alignment stage and has been aligned is sucked and held by the robot arm from below and transferred to the mount table. During this transfer process, the robot arm turns to reverse the wafer surface, that is, transfer the wafer back to the mount table.
[0008]
[Problems to be solved by the invention]
In the current market, a semiconductor wafer having a thickness of 200 μm or more is used. However, in recent years, with the demand for high-density mounting, semiconductor wafers tend to be gradually thinned to 150 to 50 μm, which is less than 200 μm.
[0009]
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 against the processing stress remaining after the back grinding decreases, so the distortion of the wafer increases.
[0010]
If the distortion of the wafer becomes large, if the tip of the robot arm is inserted under the wafer and scooped up, it will not be able to reliably hold the suction, resulting in a picking error or picking up with insufficient suction. Or When transferring a wafer taken out with insufficient suction and holding to each step, for example, when the robot arm is turned in the process of being transferred to the mount table and the back surface is turned upside down, The problem of falling will occur.
[0011]
In addition, since the edge of a thinly processed wafer is sharp, if the peripheral edge (edge) of the wafer hits the cassette wall surface during transfer of the cassette, the wafer edge is damaged. Or the wafer bites into the cassette wall. Further, if the wafer bites into the cassette wall surface, there is a possibility that problems such as a take-out error or damage to the edge occur when the wafer is taken out.
[0012]
The present invention has been made in view of such circumstances, and an object thereof is to provide a method for mounting a semiconductor wafer capable of handling a thin semiconductor wafer and a cassette used therefor.
[0013]
[Means for Solving the Problems]
In order to achieve such an object, the present invention has the following configuration.
That is, the invention according to claim 1 is a semiconductor wafer mounting method for holding a semiconductor wafer on a ring-shaped frame via an adhesive tape,
Adsorbing part of the transfer mechanism for a plurality of semiconductor wafers stored in a plurality of stages with at least the outer peripheral part of the semiconductor wafer supported by a support plate having a support surface extending from both side walls to the back side of the cassette. A process of sandwiching the outer peripheral portion of the semiconductor wafer from the back side by the tip provided with the support plate and carrying it out while adsorbing, and
A process of aligning the semiconductor wafer with the back surface facing upward;
A process of holding the semiconductor wafer on the ring-shaped frame via the adhesive tape by transporting the aligned semiconductor wafer and placing the adhesive wafer on the mount table with the back surface facing upward; It is equipped with.
[0014]
The invention described in claim 2 further comprises a process of peeling off the protective tape attached to the pattern surface of the semiconductor wafer.
[0016]
The present invention as described in claim 3 is a cassette containing a double number of semiconductor wafers in a plurality of stages,
A support portion formed from both side walls of the cassette to the back side so that at least the outer peripheral portion of the semiconductor wafer is placed with the back side facing upward;
By independently controlling the solenoid valve provided for each of the support portions provided in a plurality of stages with a connector, it is possible to independently control adsorption holding and release of the semiconductor wafer, and close the solenoid valve. A suction means that allows the semiconductor wafer to be sucked and held for a certain period of time with the connector removed;
It is characterized by comprising.
[0017]
The present specification also discloses the following solution.
[0018]
(1) A transfer mechanism for transferring a semiconductor wafer,
A semiconductor mounting apparatus comprising suction means for sucking and holding a peripheral region of a semiconductor wafer.
[0019]
According to the invention of (1), since the suction means for sucking and holding the peripheral region is provided, the semiconductor wafer can be sucked and held without being bent. As a result, the semiconductor wafer is stably held and transported. Can do.
[0020]
[Action]
The operation of the first aspect of the invention is as follows.
That is, since a plurality of semiconductor wafers are stored in a plurality of stages in the cassette with the back surface facing upward, the semiconductor wafer to be taken out can be picked up from above and taken out from the cassette. Since the taken-out semiconductor wafer is aligned with the back surface facing upward, the back surface of the semiconductor wafer is always directed upward until it is transferred to the mount table. In other words, the semiconductor wafer transfer mechanism of the conventional apparatus is equipped with a reversing mechanism for reversing the semiconductor wafer, but this mechanism becomes unnecessary. Therefore, the semiconductor wafer is prevented from dropping when the semiconductor wafer is turned over.
[0021]
According to the second aspect of the present invention, the semiconductor wafer and the ring-shaped frame are integrated on the mount table via the adhesive tape, and the protective tape is peeled off from the surface (pattern surface) of the semiconductor wafer that has been dispensed. Is done.
[0023]
According to the third aspect of the present invention, the semiconductor wafer placed on the support plate is sucked and held, so that the semiconductor wafer is held in a stable state without moving in the cassette.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing the overall configuration of a semiconductor wafer mounting device (hereinafter simply referred to as “wafer”) according to the present invention, and FIG. 2 is a diagram of a cassette for storing wafers in multiple stages.
[0025]
The semiconductor wafer mount apparatus, back-grinding the wafer supply section 1, the processing cassette C1 of the wafer W housed in the plurality of stages that have undergone is loaded, the first robot arm 2 is a wafer transport mechanism 3 is equipped with a wafer W Alignment stage 4 for alignment, alignment stage 5 for alignment of frame f, which is a ring-shaped frame, mount table 6 for mounting frame f and wafer W, and tape supply unit 7 for supplying adhesive tape T to mount table 6 A transfer mechanism 10 equipped with a second robot arm 9 for transferring a mount frame F in which a wafer W and a frame f are integrated; The peeling site 11 for peeling off the attached protective tape P and the peeling tape Tp to the peeling site 11 A tape supply unit 12 for feeding, a tape collecting unit 14 for taking up and collecting the peeled processed peeling tape Tp, a character recognition unit 15 for reading the serial number of the processed wafer W, and a barcode label on the mount frame F An upper part of the base 18 is provided with a printer 16 to be attached, a mount frame collection unit 17 in which cassettes C2 for storing the mount frames F in a plurality of stages are loaded.
[0026]
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 site 11, the character recognition unit 15, the printer 15, and the wafer collection unit 17 are included in the base 18. Whereas the tape supply unit 7 and the tape recovery unit 8 including a tape adhering unit and the like are provided on the upper surface, the tape supply unit 7 and the tape collection unit 8 are slidably provided on a member (not shown) across the mount table 6. Further, a tape supply unit 12 for supplying the release 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.
[0027]
The wafer supply unit 1 places the wafer W in a horizontal posture with the surface on which the protective tape P is attached facing down, that is, the back side facing up, on a support plate 20 provided in each stage of the cassette C1, and a plurality of these A cassette C1 containing a plurality of wafers W is loaded on a cassette table. The cassette base is turned by an air cylinder (not shown) so that the orientation can be changed.
[0028]
The cassette C1 has the characteristic configuration of the present embodiment. Hereinafter, a more specific description will be given with reference to FIGS. 2 and 3.
The cassette C1 is a flat plate having substantially the same shape as the inner 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. Support plates 20 are provided in a plurality of stages . A suction hole 21 for holding the wafer W by vacuum suction is provided at the center of the support plate 20. The suction hole 21 is connected to an electromagnetic valve 23 via a tube 22 inside the support plate 20.
[0029]
The electromagnetic valve 23 is provided on each support plate 20 and is connected to the vacuum source 25 through the air joint 24 from the upper part of the cassette C1. As the air joint 24, for example, a detachable one is used. Further, connectors 26 corresponding to the number of storage stages of the wafers W, that is, the number of support plates 20 are provided on the rear side surface of the cassette C1. This connector 26 is for transmitting a signal for independently controlling the solenoid valve 23 of each stage.
[0030]
In other words, the wafer W placed on the support plate 20 at an arbitrary location is placed on the support plate 20 and at the same time the electromagnetic valve 23 is opened (turned on) so that it is sucked and held by the suction hole 21. It has become. When removing the cassette C1 from the apparatus for storing the wafer W, the electromagnetic valve 23 is first closed, then the wiring connected to the connector 26 (for transmitting control signals) is removed, and the vacuum source 25 is removed from the air joint 24. The cassette C1 can be moved freely.
[0031]
Since the wafer W seals the suction hole 21, the vacuum suction state is maintained for a certain period after the electromagnetic valve 23 is turned off, so that the wafer W is stably held.
[0032]
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 electromagnetic valve 23 at the required location is opened (turned on). For example, the wafer W stored and held can be avoided from inadvertent vibration applied to the cassette C1.
The support plate 20 and the suction hole 21 correspond to the support portion of the present invention.
[0033]
Next, as shown in FIG. 4, the first robot arm 2 of the transport mechanism 3 has a ring-shaped tip 27, and a plurality of suction holes 28 are provided along the circumference of the center of the ring. ing. That is, when the tip 27 comes into contact with the wafer W, the wafer W is sandwiched between the tip 27 and the support plate 20, so that the distortion of the wafer W is corrected and the wafer W is circled at the tip 27. The peripheral region is held by vacuum suction.
[0034]
Further, the first robot arm 2 is configured to be able to move back and forth horizontally. The front end portion 27 is inserted into the wafer supply unit 1, the upper side of the wafer W, that is, the back surface is sucked and held, and the wafer to the alignment stage 4 is removed. W is supplied, and the wafer W is supplied from the alignment stage 4 to the mount table 6. At this time, the wafer W is sandwiched between a support portion (not shown) of the alignment stage 4 and the tip portion 27 so that the distortion of the wafer W is corrected.
[0035]
The mount table 6 transports and holds the frame f subjected to the alignment process on the alignment stage 5 by the movable table, and sucks and holds the wafer W placed at a predetermined position and posture by the first robot arm 2. It is like that.
[0036]
Moreover, the tape supply part 12 is comprised from the tape sticking unit which passes the adhesive tape T derived | led-out from the original fabric roll above the mount table 6, and the cutter mechanism K which cuts an adhesive tape. In addition, a tape collecting unit 8 that collects the cut remaining tape is also provided.
[0037]
The second robot arm 9 is configured so as to be able to move back and forth horizontally and turn, and the mount table 6 sucks and holds the mount frame F in which the wafer W and the frame f are integrated by attaching an adhesive tape, and the pattern surface faces upward. Thus, the arm is turned so that the mount frame F is reversed and carried into the peeling table.
[0038]
The tape supply part 12 supplies the peeling tape Tp derived | led-out from the original fabric roll through the upper direction of a 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 peeled together. It is configured. Note that the release tape Tp is narrower than the diameter of the wafer W.
[0039]
The character recognition unit 15 includes a CCD that reads characters such as a manufacturing number stamped on the wafer W and a computer that analyzes the read characters.
[0040]
The printer 16 newly converts the manufacturing management number into a barcode according to the character recognized by the character recognition unit 15, prints the barcode label on the mount frame F, and pastes it.
[0041]
The mount frame collection unit 17 inserts and stores the mount frame F on which the protective tape has been peeled off and the bar code is pasted into the cassette C2 with an appropriate interval in the vertical direction, and loads it onto the cassette base. It is supposed to be. This cassette stand is also turned by an air cylinder (not shown) so that the direction can be changed.
[0042]
The basic steps of the above-described embodiment apparatus will be described below with reference to FIG.
First, the tip of the first robot arm 2 is inserted into the gap of the cassette C 1 of the wafer supply unit 1, and one wafer W with the back side up is sucked and held from above and transferred onto the alignment stage 4. . Here, the alignment of the wafer W is performed based on the detection of the orientation flat or notch of the wafer W. The aligned wafer W is again attracted and held by the first robot arm 2 and transferred to the mount table 6.
[0043]
The mount table 6 includes a frame chuck portion (not shown). Then, the frame f aligned from the alignment stage 5 is supplied to the frame chuck portion and is sucked and held. At this time, the wafer W is placed on the mount table 6 in a predetermined posture and position, and is sucked and held. At this time, the sticking roller R1 of the adhesive tape T is in the standby position behind the frame f.
[0044]
Next, the affixing roller R1 rolls and moves on the wafer W and the frame f to affix the adhesive tape T. Then, the adhesive tape T is cut into a circle on the frame by the cutter mechanism K, and the remaining tape after the cutting is collected by the tape collecting unit 8.
[0045]
The mount frame F to which the adhesive tape T is attached and the frame f and the wafer W are integrated is paid out from the mount table 6, sucked and held by the second robot arm 9, and transferred to the peeling table. During this transfer process, the second robot arm 9 turns and the pattern surface of the wafer W faces upward.
[0046]
The wafer W transferred to the peeling table is placed on a suction pad (not shown) in a predetermined posture and position, and the pattern surface on which the protective tape P is attached is sucked and held in an upward posture. At this time, the peeling roller R2 is in a standby position away from the peeling table.
[0047]
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 adheres to the protective tape P integrally. The peeling tape Tp in the state is peeled off from the surface of the wafer W. At this time, the peeling tape Tp is supplied from the tape supply unit 12 in a timely manner, and the protective tape P peeled off together with the peeling tape Tp is collected by the tape collecting unit 14.
[0048]
The wafer W from which the protective tape P has been removed by the peeling tape Tp is transferred to the character recognition unit 15 by the transfer table, and the manufacturing number printed on the wafer W is recognized. Then, a label of a production management number newly bar-coded by the printer 16 is attached to the mount frame F.
[0049]
The mount frame F on which the barcode label attaching process has been performed is transported by the transport base and inserted into the cassette C2.
[0050]
Note that the configuration of the mounting process is not limited to the configuration of the above-described embodiment.
[0051]
As described above, the wafer W that has been subjected to the back grinding process is sucked and held in such a manner as to be sandwiched between the front end portion 27 and the support plate 20, thereby preventing distortion generated in the wafer W, and thus the front end portion 27 at the wafer. W can be reliably sucked and held, and stable transfer of the wafer W can be realized.
[0052]
Further, even when the cassette C1 is moved by vacuum-sucking the wafer W by the support plate 20 that covers the entire area of the wafer W and the suction holes 21 provided in the support plate 20, the wafer W is moved within the cassette C1. Can be kept stable.
[0053]
Further, the wafer W accommodated in the cassette C1 with the back surface facing upward is picked up from the upper side (back surface) of the wafer W by the first robot arm 2 having the ring-shaped tip portion 27, and is taken out. Handling, alignment, and transfer to the mount table 6 after the alignment processing, the wafer W is handled with the back surface facing upward, and as a result, the fall due to the reversal of the wafer W can be avoided.
[0054]
In addition, this invention is not limited to the said embodiment, It can deform | transform as follows.
[0055]
(1) In the above embodiment, one wafer W is sucked and held from the cassette C1 by the tip of the first robot arm 2, and the suction hole provided in the support plate of the wafer W of the cassette C1 at the time of this removal. The air may be supplied from the first robot arm 2 to support the suction holding by the first robot arm 2.
[0056]
(2) The support plate 20 of the cassette C1 of the above embodiment is configured to hold the entire area of the wafer W, but is not limited to this form. For example, as shown in FIG. You may use what reduced the weight by providing the opening part H in the center part so that W may not bend, when it mounts on a support plate.
[0057]
(3) In the above embodiment, the tip portion 27 of the first robot arm 2 has a ring shape and a plurality of suction holes 28 are provided. However, the present invention is not limited to the above embodiment. Any configuration may be used as long as the wafer W can be transported in a stable state without being bent when the wafer W is attracted and transported.
[0058]
【The invention's effect】
As is clear from the above description, according to the first aspect of the present invention, the wafers stored in a plurality of stages in the cassette are sucked and held from above with the back surface opposite to the pattern surface facing upward. By taking out and aligning with the back surface facing upward, the wafer can be handled with the back surface always facing upward until the wafer is placed on the mount table. As a result, it is possible to avoid the dropping of the wafer that occurs when the wafer is reversed during the transfer process.
[0059]
According to the second aspect of the present invention, the protective tape attached to the pattern surface of the wafer can be peeled off.
[0060]
According to the third aspect of the invention, since the wafer can be stored in a plurality of stages with the back surface of the wafer facing upward, the wafer can be picked up and taken out from above the wafer by the transfer arm. 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 taken out from the cassette. That is, the method of claim 1 can be suitably realized.
[0061]
According to the fourth aspect of the present invention, since the wafer can be held on the support portion by the suction means, the wafer can be held in a stable state without moving in the cassette.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall configuration of a semiconductor wafer mounting apparatus according to an embodiment of the present invention.
FIG. 2 is a partially broken perspective view of a cassette used in the apparatus of this embodiment.
FIG. 3 is a diagram showing a main part configuration of a cassette.
FIG. 4 is a diagram illustrating a distal end 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]
DESCRIPTION OF SYMBOLS 1 ... Wafer supply part 2 ... 1st robot arm 3 ... Wafer conveyance mechanism 4 ... Alignment stage 6 ... Mount table 20 ... Support plate 21 ... Suction hole 22 ... Pipe 23 ... Solenoid valve 24 ... Air coupling 25 ... Vacuum field 26 ... Connector 27 ... Robot arm tip 28 ... Suction hole C1 ... Cassette f ... Frame (ring-shaped frame)
F: Mount frame W: Semiconductor wafer

Claims (3)

A semiconductor wafer mounting method for holding a semiconductor wafer on a ring-shaped frame via an adhesive tape,
Adsorbing part of the transfer mechanism for a plurality of semiconductor wafers stored in a plurality of stages with at least the outer peripheral part of the semiconductor wafer supported by a support plate having a support surface extending from both side walls to the back side of the cassette. A process of sandwiching the outer peripheral portion of the semiconductor wafer from the back side by the tip provided with the support plate and carrying it out while adsorbing, and
A process of aligning the semiconductor wafer with the back surface facing upward;
A process of holding the semiconductor wafer on the ring-shaped frame via the adhesive tape by transporting the aligned semiconductor wafer and placing the adhesive wafer on the mount table with the back surface facing upward; A method for mounting a semiconductor wafer, comprising: The semiconductor wafer mounting method according to claim 1,
Furthermore, the mounting method of the semiconductor wafer provided with the process of peeling the protective tape affixed on the pattern surface of the semiconductor wafer. A cassette containing the multiple number of semiconductor wafers in a plurality of stages,
A support portion formed from both side walls of the cassette to the back side so that at least the outer peripheral portion of the semiconductor wafer is placed with the back side facing upward;
By independently controlling the solenoid valve provided for each of the support portions provided in a plurality of stages with a connector, it is possible to independently control adsorption holding and release of the semiconductor wafer, and close the solenoid valve. A suction means that allows the semiconductor wafer to be sucked and held for a certain period of time with the connector removed;
A cassette characterized by comprising

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