JP2590363B2 - Pitch converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a pitch converter for converting an arrangement pitch of a plate-like body such as a semiconductor wafer.

(Prior Art) In general, in a semiconductor manufacturing apparatus, a group of wafers mounted on a boat formed using quartz or the like is loaded into and unloaded from a heat treatment unit to perform heat diffusion processing and the like on a large number of wafers at once. ing.

Therefore, when performing such a thermal diffusion process on a wafer, a storage jig in which a plurality of wafer groups are aligned and stored,
For example, it is necessary to take out a group of wafers from a cassette or the like using a wafer transfer device, and perform a loading operation of placing the wafers on a boat. Further, after the completion of the diffusion process, it is necessary to perform an unloading operation to store the wafer group placed on the boat in the original cassette again by using the wafer transfer device.

In order to perform such an operation, the conventional wafer transfer device is provided with a pair of chucks formed to be freely openable and closable. A vertical holding groove is formed.

When the loading operation is performed, the plurality of wafers arranged and stored in the cassette are transferred to a predetermined upper position using a wafer lifting device, and the transferred wafers are sandwiched from both sides using the chuck. And transport it to the boat. Since a plurality of storage grooves are formed at regular intervals on the boat, the loaded wafers are aligned and stored along the grooves at regular intervals. Such a loading operation is repeatedly performed on a plurality of cassettes placed on the cassette floor, so that a group of wafers stored in the plurality of cassettes is successively transferred onto the boat.

Incidentally, a maximum of 25 wafers are generally stored in the cassette at a pitch of 3/16 inch, and this wafer group is usually transferred onto a boat at the same pitch using the wafer transfer device.

However, on account of performing various processes on these wafers, a plurality of wafers are placed on the boat at a pitch interval different from that in the cassette, for example, twice, three times, such as 6/16 inch pitch or 9/16 inch pitch. Transferring at pitch intervals is often required.

It is not feasible to perform such wafer transfer with a different pitch interval using a conventional fixed groove.

Therefore, various proposals for executing pitch conversion have been made, but those which change the pitch steplessly are excellent in practicability. No. 66944 discloses this.

As shown in FIG. 7, a chuck mechanism 2 including a plurality of chucks 2a for holding a plurality of wafers 1 so that respective surfaces thereof are parallel to each other, and operating the chucks 2a independently of each other. It comprises a plurality of link members 3 that can vary the pitch between them, and a drive mechanism 4 that drives the plurality of link members 3 simultaneously.

The fulcrum positions 3a of the link member 3 are different from each other, and one end of the link member 3 is moved by the same distance by the rotation of the drive mechanism, and the other end is moved by a different distance according to the fulcrum position. Then, the pitch conversion is to be executed.

(Problems to be Solved by the Invention) In the above-described conventional apparatus, a link member 3 is required for each chuck member 2a in order to independently drive the chuck members 2a, and the configurations of the link members 3 are different from each other. Therefore, there is a problem that the configuration is extremely complicated and the size of the apparatus is increased.

In addition, the movement of the multiple ends in the case where one end of the link member 3 is moved at the same distance strictly follows an arc shape, and the chuck member 2a to be moved linearly is moved by an arc-shaped locus. However, the resistance at the time of movement is large, and smooth movement cannot be ensured.

In view of the above, an object of the present invention is to solve the conventional problem described above, and to use a lead screw to reliably convert the arrangement pitch of the objects to be processed with a simple configuration and to remove dust from the threaded portion. It is an object of the present invention to provide a pitch converter capable of preventing scattering of the pitch.

It is another object of the present invention to provide a pitch converter capable of forming a thread groove having a different lead angle with high accuracy and performing high-precision pitch conversion even when the arrangement pitch is relatively narrow. .

[Structure of the Invention] (Means for Solving the Problems) The invention according to claim 1 is a pitch converter that performs pitch conversion of an arrangement pitch of a plurality of workpieces, and a plurality of workpieces are arranged one by one. A plurality of supporting portions to be supported, a lead screw in which a thread groove having a different lead angle is formed for each region to be screwed with each of the supporting portions, and a threaded portion between the lead screw and the plurality of supporting portions. A cover for covering, and means for exhausting the inside of the cover, wherein each of the support portions is moved along the screw groove by forward and reverse rotation of the lead screw, and the inside of the cover is exhausted by the exhaust means. The arrangement pitch of the object to be processed is converted.

According to a second aspect of the present invention, in a pitch converter for converting the pitch of arrangement of a plurality of workpieces, a plurality of support portions for supporting a plurality of workpieces one by one, and a plurality of the support portions are provided. A plurality of threaded portions each of which is screwed with each support portion in a region divided into a plurality of portions in the arrangement direction of the object to be processed, and in which a screw groove having a different lead angle is formed for each region screwed with the support portion. Means for synchronously rotating the plurality of lead screws in forward and reverse directions, and converting the arrangement pitch of the object by forward and reverse rotation of the plurality of lead screws. Features.

According to a third aspect of the present invention, in the second aspect, a cover that covers a threaded portion between the plurality of lead screws and the support portion and a unit that exhausts the inside of the cover are further provided. And

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the lead screw has a thread groove in which a lead feed direction is different on both sides of a center in a screw axis direction, and The thread groove having a smaller lead angle is formed as the distance from the center increases.

(Operation) In the present invention, the pitch of the plate-like body can be changed by using a special screw. That is, a bolt-nut system or the like is configured with a normal screw, and only linear movement is possible. However, the lead screw of the present invention has a common thread cutting reference point as shown in FIG. A plurality of screw grooves 10a, 10b, 10c, 10d with different leads
Etc. are formed.

The lead of each thread groove has an integer multiple relationship as shown in FIG.

Therefore, by rotating the lead screw by θ (radian), the moving piece screwed into the screw groove 10a moves from the reference point by θ · l1 / π, and similarly, each of the moving pieces screwed into the screw grooves 10b, 10c, and 10d. The moving piece moves from the reference point by θ · l2 / π, θ · 3 / π, and θ · 4 / π. Here, the relationship between the leads is l2 = 2 · l1, l3 = 3 · l1l4 = 4 · l1, so the spacing between the moving pieces is equal to θ · l1 / π, and the rotation of the lead screw This interval can be varied steplessly in proportion to the angle θ.

As a result, by moving the chuck together with the moving piece, the arrangement pitch of the plate-like bodies supported by the chuck can be changed in a stepless manner.

The thread groove is preferably formed such that the lead feed direction is different from the center as shown in FIG. 1 (B). In this case, pitch conversion is performed on the center. Therefore, the moving distance of the moving piece at the end becomes half as compared with the case of FIG. 1 (A).

According to the first aspect of the invention, by using the above-described lead screw, in addition to being able to perform simple and accurate pitch conversion accurately, dust generated in the screwed portion is exhausted and scattered out of the cover. Therefore, the pitch conversion atmosphere of the object can be kept clean.

In the invention of claim 2, in view of the difficulty in forming a plurality of types of screw grooves having different lead angles on one lead screw, the pitch conversion drive is divided into a plurality of lead screws and executed. Thereby, the thread groove formed in each lead screw can be formed with high accuracy, and the pitch conversion accuracy can be increased.
In particular, since the arrangement pitch of the objects to be processed is narrow, for example, 1/8 to 1/4 inch, it is quite difficult to form a plurality of types of screw grooves in close contact with a narrow area, and a plurality of lead screws are required. It is effective to use.

(Embodiment) Next, an embodiment in which the present invention is applied to a wafer pitch converter used in a semiconductor manufacturing apparatus will be specifically described with reference to the drawings.

As shown in FIG. 2, the wafer transfer device of this embodiment
The cassette stage 22 on which the plurality of cassettes 20 are mounted and the boat stage 32 on which the boat 30 is mounted are arranged substantially linearly adjacent to each other, and the chuck device 40 moves along each of these stages 22, 23. The moving groove 42 is provided.

The inside of the apparatus main body 300 is formed in a substantially hollow shape, and as shown in FIG.
A pair of rails 50 are provided along the rail, and the slider 52 is formed along the rail 50 so as to move.

The slide position of the slider 42 is controlled by rotating a ball screw 54 using a motor (not shown). Then, the chuck device 40 and the wafer lifting device 60 are disposed adjacent to each other, and the operation of taking out the wafer from the cassette 20 and transferring the wafer to the boat 30 and the operation of the reverse process are performed by using both the devices 40 and 60. .

In the embodiment, the cassette stage 22 is provided with a plurality of table insertion ports 24 as shown in FIG. 3 at regular intervals, and each of the cassettes 20 has an opening provided at the bottom thereof. It is placed on the table 22 so as to be located on the table 24. In each of the cassettes 20 placed in this manner, vertical grooves 20a for accommodating and holding wafers at regular intervals are formed in parallel on the inner surfaces of both walls.

In a semiconductor device, the wafer group stored in the cassette 20 is often handled as one unit. For this reason, the storage grooves 20a are provided at 25 intervals at a pitch of 3/16, and are formed so that a maximum of 25 wafers can be stored in the cassette 20 as one unit.

As shown in FIG. 3, the wafer lifting device 60 is formed so that the table 62 can be moved upward of the stage 22 through the insertion port 24.

On the surface of the table 62, a storage groove for the cassette 20 is provided.
Twenty-five wafer support grooves are formed in accordance with the pitch interval of 2a, and support the wafer w at a constant pitch interval from the lower end thereof.

Therefore, as shown in FIG. 3, by moving the table 62 upward through the insertion port 24, the plurality of wafers w stored in the cassette 20 are placed in a state where the lower ends thereof are supported by the table 62. It is transferred upward.

Then, the wafer w transferred to the upper predetermined position is pinched using the chuck device 40 functioning as a wafer pinching means, and transferred to the boat 30 via a predetermined moving path. The transfer of the wafer w to the boat 30 is performed in the fourth step.
This is performed in the same manner as the method for the cassette 20 as shown in the figure.

The chuck device 40 includes a head 44 that moves up and down in the figure as shown in FIG. 3, a pitch conversion driving unit 100 that is attached to the head 44 via an arm 46, and that can be opened and closed in the left and right directions in the figure. , Supported by this pitch conversion drive unit 100,
It has a pair of chucks 48, 48 used as a holder for holding the wafer w.

Here, as shown in FIG. 5, the pair of chucks 48, 48 are chuck portions capable of chucking one wafer w at a time.
The pitch conversion drive unit 100 converts the intervals between the chuck units 80.

The pitch conversion drive unit 100 drives a lead screw 101 by a motor (not shown) or the like to move a nut part 83 (described later) screwed to the lead screw 101, thereby performing pitch conversion. It is possible.

Here, the lead screw which is a characteristic configuration of the device of the present embodiment
101 will be described.

The thread groove formed in the lead screw 101 is formed as shown in FIG. 1 (B). That is, in the figure, the vertical axis indicates the circumferential length of the screw shaft (π · d when the screw diameter is d), and the horizontal axis indicates the amount of movement of the nut portion 83. The lead screw 101 is formed with a plurality of screw grooves having different leads. The lead of the first lead screw 10a on the right side of the center in the longitudinal direction of the shaft (lead screw 1) is formed.
If the distance in the axial direction that moves along the thread groove when rotated) is 11, the leads after the second lead screw 10b have the following relationship.

l2 = 2 · l1 l3 = 3 · l1 l4 = 4 · l1

In order to obtain such a thread groove, it is sufficient to form the groove screw by changing the lead angle. In general, when the lead is l and the screw diameter is d, tan α = π · d / l, and the lead angles α1, α2, α3, etc. may be set so that each screw groove satisfies the above relationship.

In addition, such a first screw groove 10a, a second screw groove 10 ...
b is also arranged on the left side of FIG. 1 (B), and the thread groove on the left side is formed as a reverse screw so that the lead feed direction for the same direction rotation is opposite to that of the right side. I have.

It is sufficient that each of the above-mentioned thread grooves is formed within a range of one turn, and it is not always necessary to form a thread reference point (see FIG. 1 (B)
It is not necessary to form them continuously from (the center position), but may be formed in a portion corresponding to a region where each chuck unit 80 moves.

In the case of the present embodiment, 25 wafers w at a time
25, so that the chuck groove 80 is provided on the right side of FIG. 1 (B).
A total of 24 are provided on the left side, 12 each, 13 at the center
The third corresponding fixed chuck portion 80 is arranged.

As shown in FIGS. 5 and 6, the chuck portion 80 includes:
Guide holes 82 and 82 for vertically inserting two guide shafts 85 and 85 are formed in a chuck piece 81 formed with a groove 81a for chucking a wafer w, and further screwed into the screw groove. A nut portion 83 is formed.

The chuck portion 80 is formed with slit-shaped notches 84, 84 from the upper and lower ends, and one part of the notch portions 84, 84 is housed in the cover 86, and the chuck piece on the other side is formed. Only 81 is exposed. Then, a configuration in which the inside of the cover 86 is evacuated as necessary can be adopted.

 Next, the operation will be described.

In the case of the present embodiment, the arrangement pitch of the cassettes on which the wafers w are initially mounted is 3/16 inch, and when the wafers w are mounted on the boat with this pitch, the pitch conversion is unnecessary. However, the arrangement pitch of the wafers w may be changed according to the type of the process or the like.
A pitch between 〜 inch and 1/4 inch is often adopted, and a pitch that is an integer value in mm may be adopted depending on the user.

As described above, when the wafers w are mounted on the boat at a pitch different from the arrangement pitch in the cassette, pitch conversion is performed according to the following steps.

First, the wafer w is chucked by the pair of chucks 48,48. In this case, the interval between the chuck portions 80 of the pair of chucks 48 is naturally 3/16 inch.

Next, when pitch conversion is required, the lead screw 101
Rotate in one direction. Then, this lead screw 101
Chuck part 80 having a nut part 83 screwed into the thread groove of
The pitch is converted by linearly moving the nut portion 83 along each thread groove.

That is, by rotating the lead screw by θ (radian), the moving piece screwed into the screw groove 10a moves to a position away from the reference point by θ · l1 / π, and similarly, the moving piece moves to the screw groove 10b, 10c, 10d. The moving pieces to be screwed are θ · l2 / π, θ · l3 / π, θ · l4 /
It will move to a position away from the reference point by π. Here, the relationship between the leads is as follows: l2 = 2 · l1, l3 = 3 · l1l4
= 4 · l1, the spacing between the moving pieces is θ · l1
/ π, and this interval can be changed steplessly in proportion to the rotation angle θ of the lead screw.

In the case of FIG. 1 (B), similar thread grooves are formed on the left and right sides of the center in the longitudinal direction so that the lead feed directions are opposite to each other. When the pitch is increased, the other chuck portions 80 move away from the center thirteenth chuck portion 80 which is immovable despite the rotation of the lead screw 101, and when the pitch is narrowed, As a result, the arrangement pitch of the wafers w can be arbitrarily changed. In the case where the wafer w is used as a semiconductor manufacturing apparatus as in the present embodiment, dust generated from the operating unit is generated on the wafer w. If it adheres, the yield will deteriorate. Therefore, it is desirable to cover this operating part with a cover 86. In particular, notches 84, 84 are formed in the chuck piece 81, and the cover 86 is formed in the notches 84, 84. So that it can be partially inserted Doing, it is possible to reliably prevent the scattering of dust from the drive unit. Further, preferably, the inside of the cover 86 is evacuated to discharge the generated dust, so that the operation can be more appropriately performed in a clean room.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, as the thread groove formed in the lead screw 101, it is preferable to form a reverse screw with the center as a boundary. However, as shown in FIG. May be formed.

When the number of chuck portions is large, a single lead screw may not be sufficient as in the case of the above-described embodiment, so that a plurality of lead screws with a fixed thread cutting reference position are arranged. Is preferred. A plurality of lead screws are screwed with respective support pieces in a region divided into a plurality in the arrangement direction of the wafer, and a method of driving the plurality of lead screws by synchronously rotating them is adopted. Can also.

In addition, the moving piece that engages with the lead screw is not limited to the nut portion 83, but may be any protrusion that moves along the thread groove, and is engaged via a bearing in order to smoothly perform the movement. It may be something. In addition, a method in which the lead screw side is protruded and the moving one side is formed as a groove can be similarly implemented.

[Effects of the Invention] As described above, according to the present invention, the lead formed on the lead screw is screwed into each of the screw grooves having an integral multiple relationship by the simple drive of rotating the lead screw. The moving piece and the chuck fixed to the moving piece can be moved.

The lead screw structure allows the interval between the chuck portions to be changed steplessly, and the pitch of the plate-like bodies supported one by one on the chuck portion can be changed steplessly.

[Brief description of the drawings]

1 (A) and 1 (B) are schematic explanatory views for explaining a lead screw lead according to an embodiment of the present invention, and FIG. 2 is an example of a wafer transfer apparatus to which the present invention is applied. FIG. 3 is a schematic explanatory view showing a positional relationship between a chuck and a wafer pusher, FIG. 4 is a schematic explanatory view showing a positional relationship between a chuck and a boat, and FIG. FIG. 6 is a schematic perspective view of a chuck section, and FIG. 7 is a schematic explanatory view of a conventional pitch converter. 10a, 10b, 10c, 10d ... thread groove, 80 ... chuck part, 83 ... moving piece (nut part), 86 ... cover, 101 ... lead screw, l1, l2, l3, l4 ... lead, w ... plate-like body.

Claims (4)

(57) [Claims] 1. A pitch converter for converting an arrangement pitch of a plurality of workpieces into a pitch, wherein the plurality of support sections support the plurality of workpieces one by one, and each of the support sections is screwed. A lead screw in which a screw groove having a different lead angle is formed for each region; a cover that covers a threaded portion between the lead screw and the plurality of support portions; and a unit that exhausts the inside of the cover, A pitch, wherein each of the support portions is moved along the screw groove by forward / reverse rotation of a lead screw, and the inside of the cover is exhausted by the exhaust means to change an arrangement pitch of the objects to be processed. Converter. 2. A pitch converter for converting an arrangement pitch of a plurality of workpieces into a pitch, comprising: a plurality of support portions for supporting a plurality of workpieces one by one; A plurality of lead screws, each of which is screwed with each of the support portions in the plurality of divided regions in the arrangement direction of the body, and in which a screw groove having a different lead angle is formed for each region to be screwed with the support portion Means for synchronously rotating a plurality of the lead screws in forward and reverse directions, wherein the arrangement pitch of the objects to be processed is changed by forward and reverse rotation of the plurality of lead screws. Converter. 3. The pitch converter according to claim 2, further comprising: a cover for covering a threaded portion between the plurality of lead screws and the support portion; and means for exhausting the inside of the cover. Machine. 4. The lead screw according to any one of claims 1 to 3, wherein the lead screw has a thread groove in which a lead feed direction is different on both sides of a center in a screw axis direction, and is far from the center. The pitch converter, wherein the thread groove having a smaller lead angle is formed.