JP2001210696A - Pitch-converting mechanism of wafer transfer machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pitch-converting mechanism for infinitely converting pitches of a plurality of wafers by adjusting a gap between a pair of wafers. SOLUTION: A plurality of wafer-holding plates 3 is fitted loose to a guide axis 2, which is fixed on a fixed base 1 of a pitch-converting mechanism, and pivot pins 13 are provided on fixed parts on the sides of the holding plates 3. A pair of link plates 10r and 10f, having the same strip shapes, pivot the pivot pins 13 in X shapes at pivot holes 12 at the center. The pivot holes 12 at the center penetrate connecting holes 14m and 14n provided on the ends along the length. The connecting holes 14m and 14n on the ends of the link plate 10r on the pivot pin 13 are respectively connected to the corresponding connecting holes 14m and 14n, which are provided on the other link plate 10f of the pair of link plates on the pivot pins 13 of the holding plates 3 which are adjacent to the corresponding holding plate, such that the connecting holes 14m and 14n can rotate freely via connecting pin 15m and 15n. With an adjusting means for changing a gap between any one of the holding plates 3 and the base 1 or another holding plate 3, it is possible to convert the pitches of the plurality of holding plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pitch conversion mechanism of a wafer transfer machine, and more particularly, to a stepless continuous pitch between adjacent wafers in a plurality of wafers held in parallel by the wafer transfer machine. The present invention relates to a pitch conversion mechanism of a wafer transfer machine that can be switched to the other.

[0002]

2. Description of the Related Art A typical flow of a wafer 20 in a heat treatment process will be described with reference to FIGS. Wafer carrier (or cassette) 27 holding a plurality of wafers 20
However, the carrier stage 26 is driven by the cassette drive motor 28.
Is sent to the position facing the transfer machine 25 as shown by the arrow R1. The finger 11 on the movable base 29 of the transfer machine 25 is
It is directed to the carrier stage 26 by the rotation motor 31 rotating in the direction of the arrow T, and is adjusted to the height of the carrier 27 by the transfer machine elevating mechanism 33. The movable table 29 is sent to the carrier stage 26 by the reciprocating motor 30 driven in the direction of the arrow R2, and the fingers 11 are inserted into the cassette 27 to
20 is held, and the movable table 29,
Therefore, the finger 11 is returned to the center position of the transfer machine 25.
Next, the movable base 29 is rotated by the rotation motor 31, and the finger 11 is directed to the quartz boat 32. Boat lifting mechanism
The wafer 20 is inserted together with the finger 11 by the reciprocating motor 30 into the quartz boat 32 sent to an appropriate position by 34, and after the wafer 20 is held by the quartz boat 32, the movable table 29 is moved by the reciprocating motor 30. Finger 11 is a transfer machine
Returned to 25 center position.

The wafer 20 loaded in the quartz boat 32 is
As shown in FIG. 5, the boat is moved into the quartz tube 36 of the furnace 35 by the boat elevating mechanism 34 and subjected to heat treatment. The heat-treated wafer 20 is transferred to a transfer machine by a boat lifting mechanism 34.
It is lowered to the position facing 25. Thereafter, the wafer 20 is transferred to the carrier 27 in the reverse order of the loading on the boat 32, and is carried out of the carrier stage 26.

In the semiconductor manufacturing process, a semiconductor wafer 20
Heat treatment equipment such as a furnace 35 for performing diffusion, annealing, CVD, etc., on the wafer requires extremely strict control in terms of the uniformity of the in-plane temperature of the wafer 20, the temperature history of the wafer 20, and the like. ing. This is because the temperature control of the wafer 20 in the heat treatment process greatly affects the quality and thickness of the film formed on the wafer 20 as the performance and precision of the semiconductor device become higher and higher. On the other hand, the structure of the heat treatment furnace 35 has shifted from a conventional horizontal structure to a vertical furnace having good thermal stability and production efficiency. Among the vertical furnaces, there are various types from the conventional low-speed heating / cooling type to the recent high-speed heating / cooling type, and it is very important to be able to manage various temperatures including the in-plane temperature distribution of the wafer 20. It is a feature.

[0005] In the low temperature rise / fall temperature, the wafer pitch on the quartz boat 32 is made narrower than that on the wafer carrier (or wafer cassette) 27 in order to perform a large-capacity processing, and a large number of wafers 20 are inserted into the quartz boat 32. . In addition, in the high-speed temperature rise / fall, a relatively small number of wafers 20 are inserted into the quartz boat 32 with a wider pitch than the wafer carrier 27 in order to cope with precise temperature control and large-diameter wafers 20.

For this reason, the finger 11 of the wafer transfer machine is used.
It is necessary to take out the wafer 20 from the wafer carrier 27 at the carrier pitch, and insert the wafer 20 at a different pitch depending on whether the quartz boat 32 is slowly raising or lowering the temperature or high-speed raising or lowering the temperature when loading the wafer into the quartz boat 32. become. The carrier 27 for receiving the wafer 20 to the transfer machine 25
A mechanism for converting the pitch between adjacent wafers into the pitch at the time of insertion into the quartz boat 32 has been required.

[0007]

However, it is common practice to transfer a plurality of wafers 20 at once to improve the efficiency of the process, and a carrier 27 for holding the wafers 20 is used.
The quartz boat 32 is very precise, and is required to have an accuracy of ± several tens μm. In order to drive a mechanism that performs pitch conversion with such a high level of precision, a precise and expensive mechanical element such as a ball screw must be used.

[0008] Further, the transfer machine 25 is required to have a structure that generates as little dust as possible. Therefore, a precise and expensive mechanical element such as a ball screw (not shown) of the rolling friction type must be used to drive the pitch conversion mechanism mounted on the transfer machine 25. Further, if the pitch of a plurality of wafers 20 is changed at one time, the number of ball screws required for the number of wafers 20 is required, so that the mechanism itself is large and complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pitch conversion mechanism for continuously changing the pitch of a plurality of wafers on a transfer machine by adjusting the interval between a pair of wafers.

[0010]

Referring to FIG. 1, a pitch conversion mechanism 40 of a wafer transfer machine according to the present invention has a guide shaft 2 fixed to a base 1 on a movable base 29 of a transfer machine 25. A plurality of fitted wafer holding plates 3, a pivot pin 13 provided at a predetermined portion of an end surface of each of the holding plates 3, a pair of connection holes 14m and 14n at both ends in the longitudinal direction (see FIG. 3). A pivot hole 12 (see FIG. 3) at the center of the coupling holes 14m and 14n and having the same shape pivotally supported by the pivot holes 12 to the pivot pins 13 of each holding plate 3 at mutually opposite inclinations. A pair of strip-shaped link plates 10r and 10f, and one of the link plate pairs 10r and 10f pivotally supported by the pivot pins 13 of each holding plate 3.
10 r (or 10 f) coupling hole pairs 14 m and 14 n and link plate pairs 10 pivotally supported by pivot pins 13 of adjacent holding plates 3 on both sides of the holding plate 3.
The link plate 10 having a reverse inclination (hereinafter, may be referred to as “reverse inclination”) with respect to the one link plate 10r in r · 10f.
connecting pin pairs 15m and 15n rotatably connecting the corresponding connecting holes 14m and 14n of f (or 10r), respectively, and the holding plate 3 from any one of the plurality of sheets to the base 1 or another holding plate 3.
Adjusting means for changing the distance between the holding plates 3, the pitch of the plurality of holding plates 3 connected by the link plate being converted by the adjusting means.

Preferably, the adjusting means is a means 21 (see FIG. 2A) for connecting any of the plurality of holding plates 3 to the guide shaft 2 (see FIG. 2A), A threaded drive shaft 5 penetrating through the plurality of holding plates 10 in parallel with 2, a rotating means (7, 8, 9) of the drive shaft 5, and any one of the holding plates 3 not connected to the base 1 And a driven nut 6 screwed to the drive shaft 5.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an example of a mode of coupling a plurality of holding plates 3 and a plurality of link plates 10 with respect to three adjacent holding plates 3i, 3j, and 3k. As shown in FIG. 1, each holding plate 3 has a finger 11 for holding a semiconductor wafer 20 and a finger parallel mechanism 17 outside the present invention. The finger 11 is fixed to the holding plate 3 by a finger fixing screw 16. When a large number of holding plates 3 are assembled, the pivot pins 13 are attached to predetermined portions on the end surfaces of the respective holding plates 3 so as to form a row 23 (see FIG. 2B) parallel to the guide shaft 2. In the example of FIG. 3, although the receiving holes 19i, 19j, and 19k of the pivot pins are provided in the portions of the three holding plates 3i, 3j, and 3k, the pivot pins 13i, 13j, and 13k are provided in the portions by other means. 13k may be attached respectively. The pivot pins 13i are inserted into the receiving holes 19i of the holding plate 3i by passing through the pivot holes 12ir and 12if at the center in the length direction of each pair of the strip-shaped link plates 10ir and 10if having the same shape. 10 ir · 10if link plate holding plate 3
pivot on i. In a similar manner, the pivot pin 13j pivotally supports the link plate pair 10jr · 10jf to the holding plate 3j, and the pivot pin 13k pivotally supports the link plate pair 10kr · 10kf to the holding plate 3k.

For convenience of description, attention will be focused on a pair of link plates 10jr and 10jf pivotally supported on pivot pins 13j of the central holding plate 3j among the three plates. The link plates 10jr and 10jf have a pair of coupling holes 14jrm and 14jrn and a pair of coupling holes 14jf at both ends in the longitudinal direction, respectively.
m · 14jfn, and a pivot hole 12 (in this case, 12
jr or 12jf) is the bond hole pair 14m · 14n (14jrm · 14j in this case)
rn or 14jfm / 14jfn).

One end of the link plate 10jr (or 10jf) of the link plate pair 10jr.10jf on the pivot pin 13j is a pair of connection hole pairs 14jr at both ends.
m · 14jrn and the link plate 10jr in the pair of link plates 10ir · 10if and 10kr · 10kf on the pivot pins 13i and 13k of the adjacent holding plates 3i and 3k on both sides of the holding plate 3j. A pair of coupling pins 15jm and 15jn for rotatably coupling the corresponding coupling holes 14ifm and 14kfn of 10if and 10kf are provided.

It should be noted that in the above description, a pair of link plates 10jr and 10jf pivotally supported on the pivot pin 13j has been described.
One of 10jr coupling hole pair 14jrm ・ 14jrn coupling pin pair
This is the point that only 15jm and 15jn are defined. Actually, the pair of coupling holes 14jfm and 14 of the other link plate 10jf on the pivot pin 13j
A coupling pin for jfn is also required. However, these coupling hole pairs 14jfm and 14jfn are formed by the link plate pairs on the pivot pins 13i and 13k of the adjacent holding plates 3i and 3k on both sides of the holding plate 3j.
10ir ・ 10if and 10kr ・ 10kf reverse inclined link plate 10ir and
It is rotatably connected to the corresponding connection holes 14irn and 14kfm of 10kr, and the connection pins 15km and 15in for that are connected to the pair of connection pins 15km, 15kn and 15k corresponding to the pivot pins 13i and 13k, respectively.
It belongs to im · 15in.

As means for adjusting the distance between the holding plates 3, that is, the pitch of the wafers 10 held by the holding plate 3, the embodiment shown in FIGS. 3 is the holding plate fixing means 21 (FIG.
(See (A))). Next, the threaded drive shaft 5 is pivotally supported on the base 1 in parallel with the guide shaft 2 and extends through the plurality of holding plates 3. At this time, the drive shaft 5 can freely rotate with respect to the holding plate 3. In this embodiment, a driven nut 6 meshing with the screw of the drive shaft 5 is attached to the holding plate 3 farthest from the base 1, for example, the fifth holding plate 3 from the base 1 in FIG. Further, a driving device 7 such as a rotary motor is connected to a gear train composed of gears 8 and 9,
Alternatively, it is connected to the drive shaft 5 via a transmission means equivalent to this.

Assuming that the screw pitch of the drive shaft 5 is p, if the drive shaft 5 is rotated n times, the driven nut 6
With respect to the product np. 2A and 2B show a case where the holding plates 3 are brought close to each other to form a small pitch, and FIG. 2C shows a case where the mutual spacing of the holding plates 3 is widened to make the pitch large. According to the pitch converting mechanism 40 of the present invention shown in FIG. 3, a pair of link plates 10 of the same shape is pivotally supported at a predetermined portion of each holding plate 3 at the center and the adjacent holding plate 3
Since the coupling holes 14 at both ends of each link plate are pivotally supported with each other, the distance between the holding plates 3 is kept constant regardless of the position of the holding plate 3. In other words, a plurality of holding plates 3 and therefore the wafer 11 can be held at a constant pitch.

In the example shown in FIG. 1, when one end of the five holding plates 3 is fixed to the guide shaft 2 and the multi-end one is connected to the drive shaft 5 via the driven nut 6, the pitch By rotating the p-threaded drive shaft 5, the pitch of the holding plate 3, and thus of the wafer 11, is increased by np / 4 (= np /
(5-1)) can be increased or decreased. In this mechanism, since the rotation angle of the rotating shaft 5 can be adjusted substantially steplessly, the pitch can be adjusted steplessly.

Further, the holding plate fixing means 21 shown in FIG.
Is changed not to the one closest to the base 1 but to the one closest to the base 1, so that the width of increase and decrease of the pitch of the holding plate 3 corresponding to n rotations of the drive shaft 5 is increased from np / 4 to np / 3. be able to. In short, the pitch accuracy can be selected by selecting the number of the holding plates 3 in the pitch conversion mechanism 40 and the position of the holding plate 3 to be fixed.

In this manner, the object of the present invention is to provide a "pitch conversion mechanism for continuously changing the pitch of a plurality of wafers on a transfer machine by adjusting the interval between a pair of wafers therein".

Further, from the viewpoint of the drive system of the drive shaft 5, it is easy to deal with the torque and the step angle of the motor of the drive device 7.

Further, since only one part of the drive shaft 5 and the driven nut 6 is brought into frictional contact under pressure for the pitch conversion, even when a precise and expensive mechanical element such as a ball screw is required, the frictional contact is required. The number of such elements can be minimized and the device can be manufactured at low cost.

[0023]

In the above description, the number of the guide shafts 2 is one in the embodiment of FIG. 2. However, in order to secure the parallelism of the wafer 20, two guide shafts as shown in FIG. It is also possible to use two or more than three. Also,
In the embodiment shown in FIG. 1, the drive shaft 5 is provided at the center of both guide shafts 2.

The ball bush 4 shown in FIG. 1 is inserted between the guide shaft 2 and the holding plate 3 to restrict the movement of the holding plate 3 in the plane direction. The ball bush 4 may be replaced with another suitable linear guide rail (not shown) or the like.

In the embodiment shown in FIG. 3, a pair of link plates 10r.
0f is pivotally supported by the pivot pins 13 via the ball bearings 22, respectively. In the figure, a double ring with hatching around the pivot hole 12 or the coupling hole 14 represents a ball bearing 22.
In a case where the coupling holes 14 of the two link plates 10r and the coupling holes 14 of the link plates 10f on different holding plates are coupled, an example in which the ball bearing 22 is used with one of the link plates 10r or 10f is illustrated.
Ball bearings are used for low-cost devices that do not require dust generation.
The ball bearing 22 is indispensable when dust generation is disfavored or when a transmission mechanism by rolling friction is required.

[0026]

As described above, the pitch conversion mechanism of the wafer transfer device according to the present invention connects a plurality of wafer holding plates to each other by a link mechanism, and sets a distance between only a pair of wafer holding plates in the plurality of wafer holding plates. By adjusting the pitch, the pitches of all the wafer holding plates are adjusted, so that the following remarkable effects are obtained.

(A) The number of expensive mechanical elements, such as ball screws, capable of precisely controlling the moving distance can be minimized, and the pitch conversion mechanism can be manufactured at low cost. (B) The size of the pitch can be adjusted substantially steplessly. (C) Pitch conversion of a large number of wafers can be easily handled by stacking the same pitch conversion mechanism for a small number of wafers. (D) Since the wafer holding plate to be driven for pitch conversion can be arbitrarily selected, the degree of freedom of operation is high. (E) By changing one wafer to be fixed to the guide shaft out of a plurality of wafers, the number of wafers involved in determining the pitch width can be changed, thereby improving the pitch conversion accuracy. (F) The conditions such as the torque and the step angle for the motor driving the drive shaft can be easily handled. (G) The versatility is high because there are few restriction conditions.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of a wafer pitch conversion mechanism of the present invention.

FIG. 2 is a front view and a side view of a main part of the mechanism.

FIG. 3 is an exploded perspective view showing a method of connecting the link plates.

FIG. 4 is a diagram used for explaining functions of the wafer transfer machine.

FIG. 5 is a diagram used to explain wafer loading and unloading to and from a furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Guide shaft 3 ... Wafer holding plate 4 ... Ball bush 5 ... Drive shaft 6 ... Driven nut 7 ... Drive device 8, 9 ... Gear 10 ... Link plate 11 ... Finger 12 ... Pivot hole 13 ... Pivot pin 14 ... connecting hole 15 ... connecting pin 16 ... finger fixing screw 17 ... finger parallel mechanism 19 ... pivot pin receiving hole 20 ... wafer 21 ... holding plate fixing means 22 ... ball bearing 23 ... parallel row 25 ... transfer machine 26 ... carrier Stage 27 Carrier 28 Cassette drive motor 29 Moving table 30 Reciprocating motor 31 Rotating motor 32 Quartz boat 33 Transfer machine lifting mechanism 34 Boat lifting mechanism 35 Heat treatment furnace 36 Quartz tube 40 Pitch Conversion mechanism

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihiro Suzuki, Inventor Yoshihiro Suzuki 3-20-8 Narita Nishi, Suginami-ku, Tokyo Inside Okura Electric Co., Ltd. (72) Inventor Yuichi Hayashi 3-20-8 Narita Nishi, Suginami-ku, Tokyo F term (reference) in Okura Electric Co., Ltd. 5F031 CA02 DA01 FA01 FA11 FA12 FA25 GA44 GA47 GA49 GA50 LA07 MA28 MA29 MA30

Claims (7)

[Claims] 1. A plurality of wafer holding plates loosely fitted on a guide shaft fixed to a base on a movable table of a wafer transfer machine, and pivot pins provided at predetermined positions on end surfaces of the respective holding plates. It has a pair of coupling holes at both ends in the longitudinal direction and a pivot hole at the center of the pair of coupling holes, and has the same shape which is pivotally supported on the pivot pins of each holding plate by the pivot holes at mutually opposite inclinations. A pair of strip-shaped link plates, a coupling hole pair of one link plate of a pair of link plates on a pivot pin of each holding plate, and the one of the pair of link plates on a pivot pin of a holding plate adjacent to both sides of the holding plate. A pair of coupling pins for rotatably coupling the link plate and the corresponding coupling hole of the link plate having a reverse inclination, and the distance from any one of the plurality of holding plates to the base or another holding plate. Adjusting means for changing the pitch of the plurality of holding plates joined by the link plate by the adjusting means. Wafer transfer machine pitch conversion mechanism becomes. 2. The pitch conversion mechanism according to claim 1, wherein a ball bearing for engaging with the pivot pin is provided in a central pivot hole of the strip-shaped link plate. 3. A pitch conversion mechanism according to claim 1, wherein a ball bearing is provided in a coupling hole of at least one of the link plates pivotally supported by said pivot pins. Pitch conversion mechanism of wafer transfer machine. 4. A pitch converting mechanism according to claim 1, wherein said adjusting means is a means for fixing any one of said holding plates to a guide shaft, and is pivotally supported by said base and parallel to said guide shaft. Formed by a screwed drive shaft passing through the plurality of holding plates, a rotating means of the drive shaft, and a driven nut attached to any of the holding plates not fixed to the guide shaft and screwed to the drive shaft. A pitch conversion mechanism for a wafer transfer machine. 5. The pitch conversion mechanism according to claim 4, wherein a holding plate fixed to said guide shaft is a holding plate closest to a base. 6. A pitch conversion mechanism according to claim 4, wherein the rotation means of the drive shaft is a drive motor held by the base and connected to the drive shaft by a gear train. Conversion mechanism. 7. A pitch conversion mechanism according to claim 4, wherein two parallel guide shafts are provided, and a drive shaft of said adjusting means is provided at an intermediate portion between said two parallel guide shafts. The pitch conversion mechanism of the wafer transfer machine provided.