JP2908161B2 - Cassette magazine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cassette magazine for transporting semiconductor wafers in a process, and more particularly, to a cassette magazine capable of automation of work flow management and delivery to various processing devices.

[0002]

2. Description of the Related Art A semiconductor wafer used as a substrate of a semiconductor device is obtained by slicing a single crystal ingot of, for example, silicon in a direction perpendicular to a plane of a rod axis thereof, chamfering, lapping, and etching the resultant. ,
A mirror surface wafer is obtained by sequentially performing processing such as polishing.

[0003] In performing such various kinds of processing, silicon wafers are classified according to various purposes such as types, ingots, resistances, and oxygen concentrations.
Processing is performed for each lot of about 0 sheets.

Processing is performed in a state of being divided for each lot because processing specifications corresponding to various purposes are different, and when a defect occurs in a semiconductor device,
If the cause is present in the wafer, the process conditions and the like at the time of manufacturing the wafer are verified, and the results are provided for cause analysis and feedback to the process conditions and the like.

Therefore, it is important not only to sort wafers by lot, but also to verify process conditions such as heat history at the time of pulling up. Therefore, the order of slicing is managed by some method. There is a need.

For this reason, conventionally, a jig for accommodating wafers called a cassette has been adopted, and wafers are sequentially accommodated in the cassette, and the cassettes are sorted by lot and conveyed in the processing step. I was

[0007] However, although such a cassette can usually accommodate about 25 wafers, one lot is about 250 wafers in many cases, so that about 10 cassettes are considered as one unit in a processing step. Had to be transported. Therefore, in order to prevent cassettes of different lots from being mixed, cassettes of the same lot are further housed in a box called a container, and the containers are transported in the process in units of containers.

[0008]

However, in the conventional method of transferring a wafer using a cassette and a container,
There were various problems as follows.

First, a cassette accommodating about 25 wafers is routed in the process by using about 10 cassettes as one unit if the number of wafers in one lot is about 250, but is stored in one container. In some cases, it was not possible to accommodate all cassettes in one lot, and in many cases, wafers in one lot often spread over several containers.

Conversely, in some cases, the number of wafers in one lot may be small. For example, even if the number of wafers in one lot is sufficient for one cassette, this one lot is used so that cassettes of another lot are not mixed. Only the cassette was housed in one container and the process was handled.

That is, the cassettes of the same lot are always accommodated in one container, and one or a plurality of containers are mounted on a cart and transported in units of one lot.

When the handling of cassettes and containers is considered in order to avoid mixing between lots as described above, the transportation by the hand cart becomes wasteful especially when the number of wafers in one lot is small.

On the other hand, depending on the processing step, wafers of different lots may be processed collectively, and in such a case, containers of different lots may be piled up on the line side. Therefore, depending on the processing order, it may be necessary to take out the lower one of the stacked containers, and the work of extracting the desired container is extremely complicated. There was also a risk of giving.

In addition to these problems, all the conventional wafer cassettes are handed over to each processing apparatus, and therefore, it is sufficiently considered that the wafers may be damaged each time they are handed over.

As described above, when a semiconductor wafer is handled, it is possible to verify the manufacturing history of each wafer and to prevent mixing between lots that are desirably divided. There has been a demand for the development of a comprehensive flow management system having all of the manufacturing quality, production technology, and production control, which can satisfy the original requirements in terms of quality such as adhesion prevention.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and can efficiently transfer a wafer while preventing damage to the wafer and preventing mixing between lots. It is intended to provide a cassette magazine.

[0017]

In order to achieve the above object, a cassette magazine according to the present invention is a cassette magazine for storing a cassette for accommodating a plurality of semiconductor wafers in a fixed position, comprising: a fixed base plate; A rotary table mounted on the rotary table and rotatably provided with respect to the fixed base plate; a rotary table provided on the rotary table and tilted in advance by a predetermined angle downward in a rearward direction of the semiconductor wafer with respect to the cassette;
In comprising a plurality of cassette shelves provided tiltably, and a removable cover provided to cover the cassette shelf provided on the rotary table, the fixed baseplate
The cassette shelf is held horizontally on the table and rotating table.
Through holes for inserting push-up pins for
That, it is characterized in that.

[0018]

A cassette accommodating a plurality of semiconductor wafers is stored on a cassette shelf provided on a rotary table. In particular, if the number of cassettes that can be stored in the cassette shelf is set to the maximum number of one lot, one lot of semiconductor wafers will always be loaded in one cassette magazine, and semiconductor wafers of different lots will be processed in the process. There is no risk of mixing.

Further, since the rotary table according to the present invention is provided rotatably with respect to the base plate, when the semiconductor wafer is transferred in a processing step, the rotary table is fixed at a predetermined angle with the base plate fixed. By rotating the semiconductor wafer, the semiconductor wafers stored in each cassette can be sequentially taken out or returned.

Further, since the cassette shelf provided on the rotary table is provided so as to be tiltable in the direction in which the semiconductor wafers are stored, the cassette shelf is tilted during the transfer, and is kept horizontal only when the semiconductor wafers are transferred. This makes it possible to prevent the semiconductor wafer from jumping out during transportation, and to smoothly deliver the semiconductor wafer.

Since the cover is detachably provided on the rotary table so as to cover the cassette shelf, if the cover is attached during the transfer and the cover is removed only when the semiconductor wafer is transferred, the transfer work can be performed. It is possible to exhibit a dustproof effect during transportation without any trouble.

[0022]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a cassette magazine according to an embodiment of the present invention, FIG. 2A is a plan view showing the cassette magazine of the embodiment, FIG. 2B is a side view thereof, and FIG.
FIG. 3A is a sectional view taken along line AA in FIG.
FIG. 2B is a sectional view taken along the line BB of FIG.

Cassette Magazine The cassette magazine M of this embodiment has a base plate 1 made of synthetic resin such as polyvinyl chloride.
As shown in (a), a concave portion 5 is formed in which the turntable 2 is fitted and placed.

An identification label 6 such as a bar code is attached to the back surface of the base plate 1 so that it can be compared with an identification label (not shown) attached to each cassette C. For example, using a host computer or the like, it is determined whether a cassette C containing a specific semiconductor wafer W is stored in which cassette magazine M, and furthermore, which cassette shelf 3 of the cassette magazine M is stored. It can be stored and retrieved. The information of the bar code label 6 attached to the back surface of the base plate 1 is read by a bar code reader (not shown) arranged in each step or the like, and is output to a host computer or the like.

The material forming the base plate 1 is not limited to a synthetic resin, but a light metal such as aluminum can be used. The structure for rotatably mounting the turntable 2 is not limited to the fitting structure formed by the recesses 5 formed in the base plate 1, and the base plate 1
A fitting structure in which a convex portion is formed on the rotary table 2 and a concave portion is formed on the rotary table 2 side may be used. However, as described later, in this embodiment, the base plate 1 is formed of polyvinyl chloride,
Since the turntable 2 is made of aluminum, the structure shown in FIG. 3A is adopted in consideration of the workability of both.

The rotary table 2 is made of aluminum, and has a recess formed in the base plate 1 as described above.
5 , but rotatably provided with respect to the base plate 1. This is because the semiconductor wafers W can be moved from the cassette shelves 3 mounted on the turntable 2 at regular intervals.
This is because the direction of the cassette shelf 3 is sequentially changed even when the base plate 1 is fixed to a conveyor or the like when sequentially taking out or returning the cassette shelves.

Rotary table 2 with respect to base plate 1
The specific structure for rotating is as follows.
That is, as shown in FIGS. 2A and 3A,
First, four through holes 7 are formed in the base plate 1, and the ball bearing 8 of the magazine stand S penetrates the four through holes 7 to push up the rotary table 2, whereby the rotary table 2 is moved to the base plate 1. Rise from. A through hole 10 through which the rotating shaft 9 passes is formed in the center of the base plate 1.
An engagement hole 12 for engaging with a pin 11 formed at the tip of the rotating shaft 9 is formed on the back surface of the rotating shaft 9.

After the ball bearing 8 is raised, the rotary shaft 9 is also raised, and after passing through the through hole 10 and the pin 11 is engaged with the engaging hole 12, the rotary shaft 9 is rotated by a predetermined angle. By doing so, the turntable 2 supported by the ball bearing 8 rotates smoothly. When the rotary table 2 is rotated by a predetermined angle, the ball bearing 8 and the rotary shaft 9 are lowered, and the rotary table 2 is mounted on the base plate again. The ball bearing 8 described above
Is a specific example, and other means may be employed in the cassette magazine M of the present invention.

A cassette shelf 3 on which a plurality of cassettes C each containing a plurality of semiconductor wafers W can be stored is formed on the rotary table 2. For example, in the embodiment shown in FIG. 1 and FIG.
Cassettes (= 300 wafers), and 4 cassettes (= 200 wafers) for an 8-inch wafer so that 8 cassettes (= 200 wafers) can be stored on the rotary table 2 (that is, 9 wafers).
Each cassette shelf 3 is formed at an interval of 0 °. In the case of a 6-inch cassette, three cassettes C (two cassettes in the case of 8 inches) can be stacked on one cassette shelf 3. It has become.

In this embodiment, in particular, the reference position of the semiconductor wafer W in each cassette C is kept constant, for example, as shown in FIG.
The h _1, h ₂ shown in (b) in the constant irrespective specifications of the wafer W and the cassette C, and to allow accurately grasp operations of the semiconductor wafer W by the handling robot R.

However, when the storage pitch of the wafer W in the cassette C is different, such as in the case of a 6-inch wafer and an 8-inch wafer, the bar code information of the cassette magazine M or the cassette C is output to the handling robot R. This is dealt with by changing the operation trajectory mode of the handling robot R.

The cassette shelf 3 is structurally constructed as shown in FIG.
(B) and FIG. 3 (b), the cassette shelf 3
And a mounting plate 14 on which the cassette C is mounted, which are rotatably mounted on a bracket 15 fixed on the rotary table 2.

The semiconductor wafer cassette C used in this embodiment has a structure in which the semiconductor wafers W are inserted horizontally at a predetermined pitch and stored therein as shown in FIG. The semiconductor wafer may fall off due to vibration at the time. Therefore, when mounting the cassette shelf 3 on the rotary table 2,
If the cassette shelf 3 is provided so as to be tiltable, and particularly if the cassette shelf 3 is lowered backward as shown by the solid line in FIG. 3B, it is possible to prevent the semiconductor wafers from dropping during the transfer.

However, it can be said that it is preferable that the cassette shelf 3 is tilted downward at the time of transportation. However, when the semiconductor wafer W is transferred to a processing apparatus or the like, it is preferable that the cassette shelf 3 is horizontal. In some cases, it may be appropriate in view of the damage to W. Therefore, in this embodiment, a through hole 16 through which a push-up pin 17 rising from the magazine stand S penetrates is formed in the base plate 1 and the turntable 2, and as shown in FIG. 16, the cassette shelf 3 is pushed up horizontally.
When the semiconductor wafer W is delivered, this posture is maintained.

The cassette magazine M of this embodiment has a cylindrical dustproof cover 4 as shown in FIGS. 1 and 2, and is set so as to cover each cassette C stored in the cassette shelf 3. . The side and ceiling of the dust cover 4 are made of a transparent synthetic resin such as polycarbonate, and a flange 4a is formed at the lower edge for reinforcing and opening / closing the cover with a magazine stand.
The flange portion 4a is formed at a position where it does not hinder delivery of the semiconductor wafer to the processing apparatus, and further has a hole 18 into which a pin 19 of an opening / closing mechanism provided on the magazine stand S is inserted.

Next, a preferred magazine stand S used for transferring a semiconductor wafer W to a processing apparatus or the like using the cassette magazine M of the present invention will be described. FIG.
FIG. 5 is a plan view showing a magazine stand in which the cassette magazine according to the present invention is used, and FIG. 5 is a sectional view taken along the line CC in FIG.

The magazine stand S according to the present embodiment includes a belt conveyor 20 for transferring a cassette magazine M from a carrier, a rotating mechanism for rotating the rotary table 2 of the cassette magazine M, and a cassette for the cassette magazine M. A horizontal maintenance mechanism for keeping the shelf 3 horizontal, an opening / closing mechanism for opening and closing the dustproof cover 4 of the cassette magazine M, and a handling robot R for taking semiconductor wafers W in and out of the cassette C are provided.

Belt Conveyor The belt conveyer 20 has a pair of belts 22 laid on a plurality of rotating rollers 21 and rotated by a drive motor (not shown), and carries the base plate 1 in and out in the direction of the arrow in FIG. At the stop end of the base plate 1, FIG.
As shown in (1), a stopper pin 23 whose position can be adjusted is provided, and the stopper pin 23 determines the position in the moving direction.

As shown in FIG. 4, a positioning plate 25 having positioning rollers 24 is provided on both sides of the conveyed base plate 1, and at least one of the positioning rollers 24 (and / or Alternatively, a positioning plate 25) is provided movably so that positioning in the left-right direction is performed.

The presence or absence of the cassette magazine M is detected by a photoelectric sensor 26 (see FIG. 5) provided below the base plate 1, and when the cassette magazine M is transported to a fixed position, the belt conveyor 20 stops. Also,
When the loading of the cassette magazine M is completed, the entire belt conveyor 20 is lowered by being supported by the guide pins 43 and the bushes 44 and by operating one fluid cylinder 42, and comes to a position where it does not contact the base plate 1. ing.

Two guide poles 30 are provided between the upper plate 28 and the lower plate 29 fixed to the frame 27 of the rotating table magazine stand S of the rotary table.
The guide bush 31 is slidably fitted into each of the two. A movable plate 32 is fixed to these guide bushes 31, and the tip of a rod 34 of a fluid cylinder 33 attached to the lower plate 29 is fixed to the movable plate 32.

Therefore, when the rod 34 is raised by driving the fluid cylinder 33, the movable plate 32 is raised while the guide bush 31 slides along the guide pole 30.

A reducer 35 connected to an output shaft of a rotary motor (not shown) is fixed to the movable plate 32. The rotary shaft 9 is fixed to the upper plate 28 via the reducer 35. The rotating shaft 9 is vertically movable and rotatable with respect to the upper plate 28 by being provided through the bearing bush 36. Also, the speed reducer 35
The four ball bearings 8 each having a ball 8a at the tip are fixed to the plate 37 fixed to the movable plate 32, and move up together with the rotating shaft 9 as the movable plate 32 rises.

A fluid cylinder 38 is fixed on the upper plate 28 of the horizontal mechanism of the cassette shelf, and a push-up pin 17 at the tip of a rod has a through hole 16 formed in the base plate 1 and the rotary table 2 of the cassette magazine M. To push up the bottom of the cassette shelf 3 to keep the cassette shelf 3 horizontal.

Since the mechanism for maintaining the cassette shelf 3 horizontally by the fluid cylinder 38 is necessary only when the semiconductor wafer W is taken in and out of the cassette C, for example, the position where the handling robot R is installed (FIG. 4) Only).

Dust Cover Opening / Closing Mechanism In the magazine stand S of this embodiment, a pin 19 is inserted into the hole 18 of the dustproof cover 4 shown in FIG. When the access to the semiconductor wafer W is completed by pushing up the dust-proof cover 4, the dust-proof cover 4 is attached again and dust and the like adhere to the semiconductor wafer W when the access to the semiconductor wafer W is completed. To prevent

More specifically, as shown in FIG. 5, rack and pinion gear boxes 39 corresponding to the number of holes 18 are fixed to the upper plate 28, and the pins 19 having the racks are connected to the rack and pinion mechanism. Up and down. At this time, in order to equalize the ascending and descending speeds of the pins 19 and to suppress the inclination of the dust cover 4 supported by the pins 19, only one motor drives the pinion in the gear box 39, and Box 3
Reference numeral 9 is connected so as to be synchronized by a rotation transmitting member (not shown).

Note that the ascending and descending limits of the pin 19, that is, the positioning of the ascending position (open position) and the descending position (set position in the cassette magazine) of the dustproof cover 4 are as follows.
This is performed by detecting a predetermined position of the pin 19 with a proximity switch or the like.

Handling robot As shown in FIG. 4, the magazine stand S according to this embodiment
Is provided with a handling robot R for taking in and out the semiconductor wafer W stored in the cassette C with respect to processing equipment such as chamfering, lapping, etching, and polishing. In addition, a multi-axis arm is provided according to the requirements of each processing step.

In FIG. 5, "40" indicates the cassette C
2 is a photoelectric sensor for detecting the presence or absence of the semiconductor wafer W in the cassette magazine M, and includes a through hole 41 (see FIG. 2) formed in the base plate 1 and the turntable 2 of the cassette magazine M.
(Refer to (a)), the detection light is applied to the semiconductor wafer W stored in the cassette C. Therefore, if no semiconductor wafer W is stored in the cassette C, no reflected light is returned to the photoelectric sensor 40, and this result is output to the handling robot R to prevent unnecessary work in advance. can do.

Next, the operation will be described. First, the single crystal ingot is sliced in the direction perpendicular to the plane of the rod axis, the plurality of obtained semiconductor wafers W are divided into predetermined lots, and then stored in the cassette C in the order of slicing. And
Cassettes C of the same lot are stored in one cassette magazine M
To be mounted on.

In the present embodiment, the number of semiconductor wafers in one lot is usually about 250 to 300 (200 for 8 inches).
12 wafers (= 300 wafers) for a 6-inch wafer, and 8 cassettes (= 200 wafers) for an 8-inch wafer.
Thus, a maximum of one cassette magazine is sufficient for a 6-inch wafer, and a maximum of one cassette magazine is sufficient for an 8-inch wafer.

Particularly, in order to prevent semiconductor wafers of different lots from being mixed in the process, it is preferable that all the cassettes C stored in one cassette magazine M be the same lot of cassettes C.

Further, since the cassette shelf 3 provided on the rotary table 2 is provided so as to be tiltable in the storage direction X of the semiconductor wafer W, the cassette C tilts backward during the transfer, and the vibration during the transfer is performed. For example, the semiconductor wafer W can be prevented from jumping out of the cassette C.

In this manner, the cassette C is
After the cassette magazine M is stored, the cassette magazine M is transported to a target processing step using an automatic transport vehicle or the like, and the above-described magazine stand S is provided at the entrance of each processing step. Then, the cassette magazine M transferred from the automatic carrier is sent by the belt conveyor 20 until the cassette magazine M abuts against the stopper pin 23 for positioning, and left and right positioning is performed by the positioning roller 24.

By the way, when the cassette magazine M is delivered, the bar code mark 6 attached to the back surface of the base plate 1 is read, and information on the semiconductor wafer W carried into the processing step is sent to the host computer. Sent.

When the positioning of the cassette magazine M is completed, the belt conveyor 20 stops, and the operation of taking out the semiconductor wafer W is started. In this case, first, the dustproof cover 4 is pushed up to enable the handling robot R to access the semiconductor wafer.

That is, the motors (not shown) are operated to raise the respective pins 19 synchronously via the gear box 39 of the rack and pinion. With the rise of the pins 19, the tips of the pins fit into the holes 18 formed in the flange 4a of the dustproof cover 4, and the dustproof cover 4 starts to rise as the pins 19 further rise. The upper limit of the dust cover 4 is detected by detecting a predetermined position of the pin 19 with a proximity sensor or the like, and outputting this to the motor stops the motor. Thus, the dustproof cover 4 is opened, and the operation of the handling robot R for the semiconductor wafer W stored in the cassette C starts.

When loading and unloading semiconductor wafers W by the handling robot R, the rotary table 2 is rotated so that the cassette shelf 3 storing the target cassette C is located at a position facing the handling robot R.

That is, first, the fluid cylinder 33 is operated. As a result, the movable plate 32, the speed reducer 35, the rotating shaft 9 and the ball bearing 8 rise integrally, the rotating shaft 9 passes through the through-hole 10 of the base plate 1, and the leading end thereof is 12 is engaged.

At about the same time, the ball bearing 8 passes through the through hole 7 of the base plate 1 and pushes up the back surface of the turntable 2 to slightly lift the turntable 2 from the base plate 1. Activate the rotation motor from this state,
After rotating the rotating shaft 9 by a predetermined angle via the speed reducer 35, the rod 34 of the fluid cylinder 33 is lowered and the rotary table 2 is mounted on the base plate 1 again. As a result, the target cassette shelf 3 rotates to the position facing the handling robot R.

Next, the fluid cylinder 38 attached to the upper plate 28 is operated to raise the push-up pin 17. As a result, the tip of the push-up pin 17 passes through the through-hole 16 of the base plate 1 and the rotary table 2 to push up the bottom surface of the cassette shelf 3. Since the stroke of the push-up pin 17 is set so that the cassette shelf 3 is horizontal, the handling operation of the semiconductor wafer W stored in the cassette C of the cassette shelf 3 accessed by the handling robot R can be performed smoothly. In addition, it will be kept horizontal during the operation.

When the loading and unloading of the semiconductor wafers W by the handling robot R is completed, the next cassette shelf C is rotated to a position facing the handling robot R. At this time, the push-up pin 17 is once lowered. When the operation for all the cassettes C on the turntable 2 is completed, the pins 19 are lowered to close the dust-proof cover 4, and the belt conveyor 20 is operated in the reverse direction (unloading direction) to discharge the cassette magazine M.

Incidentally, depending on the processing step, the handling robot of the magazine stand described above may be omitted, and the cassette may be manually taken out or returned from the cassette magazine. However,
Even in such a process, the cassette magazine of the present invention effectively functions in preventing mixing between lots and performing efficient transport.

The embodiments described above are described to facilitate understanding of the present invention, but not to limit the present invention. Therefore, each element disclosed in the above-described embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, the configuration of the magazine stand using the cassette magazine of the present invention is not limited to the embodiment shown in FIGS. 4 and 5, and at least the rotating mechanism of the rotary table and the horizontal maintaining mechanism of the cassette shelf are provided. As long as it is provided, it can be appropriately changed according to the intended processing step. In addition, the processing steps in which the cassette magazine of the present invention is used are not limited to the above-described steps of chamfering, lapping, etching, polishing and the like of the semiconductor wafer. Any process that can be applied can be applied.

[0067]

As described above, according to the present invention, there is provided a cassette magazine capable of efficiently transporting semiconductor wafers while preventing damage to semiconductor wafers and preventing mixing between lots. Can be. Further, automation of such a delivery operation of the semiconductor wafer can be expected.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cassette magazine according to one embodiment of the present invention.

FIG. 2A is a plan view showing the cassette magazine of the embodiment, and FIG. 2B is a side view of the same.

FIG. 3A is a sectional view taken along line AA of FIG. 2A;
FIG. 2B is a sectional view taken along the line BB of FIG.

FIG. 4 is a plan view showing a magazine stand in which the cassette magazine according to the present invention is used.

FIG. 5 is a sectional view taken along line CC of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base plate 2 ... Rotary table 3 ... Cassette shelf 4 ... Dustproof cover 8 ... Ball bearing 9 ... Rotating shaft 17 ... Push-up pin 19 ... Pin 20 ... Belt conveyor W ... Semiconductor wafer C ... Cassette M ... Cassette magazine S ... Magazine stand R … Handling robot X… Semiconductor wafer storage direction

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-156952 (JP, A) JP-A-3-248443 (JP, A) JP-A-57-126144 (JP, A) JP-A-3-15644 203253 (JP, A) Hikaru 4-113446 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/68

Claims (1)

(57) [Claims] 1. A cassette magazine (M) for storing a cassette (C) for accommodating a plurality of semiconductor wafers (W) in a fixed position and transporting the cassette (C) to a target position. 1) a rotary table (2) mounted on the fixed base plate (1) and rotatably provided with respect to the fixed base plate (1); and a rotary table (2) provided on the rotary table (2). A plurality of cassette shelves (3) provided to be tiltable in a state of being tilted in advance by a predetermined angle downward in the storage direction (X) of the semiconductor wafer (W) with respect to the cassette (C); Removable cover (4) provided to cover the provided cassette shelf (3)
With the door, the fixed base plate (1) and the turntable (2)
A pusher for holding the cassette shelf (3) horizontally.
A cassette magazine , wherein a through hole through which an upper pin is inserted is formed .