JPH04106952A - semiconductor manufacturing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to wafer transfer in a vertical CVD diffusion apparatus.

[Conventional technology CVD processing is one of the manufacturing processes for semiconductor devices.

This involves heating the required number of silicon wafers in a CVD device and performing chemical vapor deposition (CVD).
In order to ensure uniform CVD processing, multiple dummy wafers are arranged at both ends of the row to sandwich the product wafers, and inspection monitors are placed at required intervals along the way of the product wafers. One wafer each is arranged. This will be briefly explained with reference to FIG.

In the diffusion furnace, the wafers 1 are supported by a boat 2. When performing CVD processing on the wafers 1 in the diffusion furnace, the wafers 1 are first inserted into the boat 2 in the desired arrangement, and then the wafers 1 are The inserted boat 2 is charged into a diffusion furnace. Generally, the inside of a diffusion furnace does not have a uniform temperature distribution over the entire area, and therefore the boat 2 has a sufficient number of wafers to process (for example, 1.5 times the number of wafers to be processed). wafer storage space for the number of wafers (number of wafers), and when processing wafers, the wafer storage position on the boat 2 can be selected according to the number of wafers, or in a place with uniform temperature distribution. There is.

A dummy wafer group 3.4 consisting of an appropriate number of dummy wafers 1b is stored at the upper and lower ends of the wafer array of the boat 2, respectively, and a group 3.4 of dummy wafers consisting of a predetermined number of product wafers 1a is stored between the monitor wafers 1C. Wafer group 5
Further, a group of product wafers 5 are sequentially stored with the monitor wafer 1C in between. A monitor wafer 1C is inserted between the product wafer group 5 at the bottom and the dummy wafer group 4. The wafer transfer device carries out a series of operations in which wafers loaded in cassettes are transferred to the boat, and wafers after processing are loaded into empty cassettes.

A conventional wafer transfer device will be explained with reference to FIG.

The one shown in FIG. 4 shows a single-wafer type (one-by-one transfer system) wafer transfer device, in which a cassette 7 loaded with wafers 1 is placed around the handling unit 6.
are arranged on the same circumference, and the hand link uni・
- A transfer elevator 8 and a load/unload elevator 9 are provided adjacent to the throat 6, and the port pedestal 10 of the transfer elevator 8 rises and falls along the generatrix of the cylindrical surface including the circumference. A vertical diffusion furnace 12 is provided above the boat pedestal 11 of the load/unload elevator 9. Further, a transfer unit 13 for transferring the boat 2 is provided between the transfer elevator 8 and the loading/unloading elevator 9.

The handling unit 6 includes a rotating arm 14 that rotates around the center of the circumference and moves up and down, and a wafer suction chuck 15 that moves back and forth in the radial direction along the rotating arm 14, and picks up the wafers 1 loaded in the cassette 7. The wafers are picked up and taken out one by one, and sequentially transferred from the top to the boat 2 placed on the transfer elevator 8.The transfer elevator 8 follows the progress of the transfer of the wafers 1, descend step by step.

After the transfer of the wafers 1 has been completed, the boat 2 is transferred from the transfer elevator 8 to the load/unload elevator 9 by the transfer unit 13, and the load/unload elevator 9 charges the boat 2 into the diffusion furnace 12. do.

When the CVD process is completed, the boat 2 is taken out from the diffusion furnace 12, transferred to the transfer elevator 8 by the transfer unit 13, and loaded into the cassette 7 by the handling unit 6 in the reverse procedure to that described above.

The above-mentioned conventional transfer device is a single-wafer type, but there is also a batch-type type as shown in FIG.

This system is equipped with a wafer suction chuck 15 or 25 sets of suction plates 16, and is used to chuck all 25 wafers 1 loaded in a cassette 7 and transfer them to the boat 2.

[Problems to be Solved by the Invention] However, the above-described conventional single-wafer type transfer apparatus and bulk type transfer apparatus have the following problems.

Arrangement of wafers inserted into the hoard 2, upper stage,
The number of dummy wafers in the lower row, or how many monitor wafers to include in the product wafers and how many monitor wafers to provide, vary depending on the processing conditions or the customer's processing specifications.

The former single-wafer method transfers wafers one by one, so it can accommodate any arrangement of wafers. However, the number of operations is extremely large, which increases the transfer time, resulting in poor efficiency.Moreover, the large number of operations increases the probability of dust generation, which adversely affects product quality.

On the other hand, the latter method has the advantage of short transfer time and is extremely efficient, but since it processes 25 wafers in batches, it is not possible to arrange the wafers when transferring them. Therefore, when loading wafers into a cassette, dummy wafers, monitor wafers, and product wafers are mixed in a predetermined arrangement. Loading wafers into cassettes is a manual process, and loading different types of wafers into a predetermined array is very complicated and inefficient, and the current situation is that incorrect insertion is unavoidable. Ta.

In view of these circumstances, the present invention seeks to provide a wafer transfer device that can fully utilize the advantages of the single-wafer method and the batch method.

[Means for Solving the Problems] The present invention is characterized in that, in a wafer transfer device equipped with a required number of wafer transfer plates, at least one of the plates can be moved forward and backward. In addition, in a wafer transfer device equipped with a required number of wafer transfer grates (171), all but the top or bottom of the grates are connected to a pitch variable screw rod, and the screw rods are connected to a variable pitch screw rod. It is characterized in that the thread pitch of the threaded portion of the plate is changed to correspond to the position of the plate.

"Function" When transferring the required number of wafers at once, place each plate at the same position in the vertical direction, place the wafers at the same time, and perform the transfer operation. For example, when transferring one wafer, The plate is advanced, and the wafer is placed on the plate to transfer the wafer.Also, if the wafer storage pitch changes, the pitch variable screw rod is rotated to adjust to the change in the storage pitch. Make it correspond.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

What is shown in FIGS. 1 and 2 particularly shows the wafer gripping section 18 of the wafer transfer device according to the present example, and the wafer gripping section 18 is rotated as shown in FIGS. 4 and 5, for example. It is provided on the arm 14 so that it can move forward and backward in the radial direction.

Hereinafter, a vertical substrate 20 will be fixed to the second base plate 19, which will be described with reference to the gripping section 18, and an upper substrate 21 will also be fixed via a support (not shown).

A kite block 22 is fixed to the upper substrate 21, and a pair of left and right sliders 23°24.25 are attached to the kite block 22.
．． 26 so that it can slide freely. The slider 23.24,
25 and 26 are screwed into screw rods 27 and 28 rotatably provided on the upper substrate 21, respectively, and driven gears 29 and 30 are fitted into the upper ends of the screw rods 27 and 28, respectively.

A pitch change motor 31 is installed between both driven gears 29.30, and a drive gear 32 fitted to the output shaft of the pitch change motor 31 is meshed with both driven gears 29.30.

Inverted-shaped plate holders 34, 35, 36.37 are fixed to the sliders 23, 24, 25.26, respectively, and wafer support plates 39, 40, Install 41.42. Each wafer support plate 38, 39.40, 41.4
A recess 43 on which a wafer can be placed is formed on the upper surface of the wafer 2 .

The plate holders 34, 35, 36, 37 are shaped to support the wafer support plates 39, 40, 41, 42 at appropriate intervals in the vertical direction, and the plate holders 34, 35, 36, . The screw rods 27, 28 are engaged with the sliders 23, 24, 25, 26 to which the screw rods 37 are fixed. For the thread pitch that is screwed together,
The screw pitch of the part where the slider 24 to which the plate holder 35 that supports the support plate 40 in the third stage from the bottom is fixed is screwed is twice, and similarly the slider 25 in the fourth stage from the bottom
The screw pitch of the slider 26 of the fifth stage is three times that of the slider 26, and the screw pitch of the slider 26 of the fifth stage is four times that of the slider 26. However, the pitch between each wafer support plate 38, 39, 40, 41, 42 can be expanded or reduced while maintaining the relationship that the pitch is equal.

The first-stage support plate 38 is fixed to a plate holder 33 attached to the advance/retreat mechanism 44, and is configured to move forward and backward without vertical displacement.

The advancing/retracting mechanism 44 will be explained below.

Parallel swing links 45, 46 are pivotally connected to the vertical substrate 20, and intermediate portions of floating parallel links 47, 48 are pivotally connected to the parallel swing links 45, 46, respectively. The floating parallel link 4
7. The upper end of 48 is pivotally connected to the first stage plate holder 33, and the lower end of the floating parallel link 47°48 is attached to the slider 4.
It is pivoted to 9. The slider 49 is slidably provided on the vertical substrate 20 via an oid 50.

Thus, the radius of rotation of the parallel swing links 44, 46 and the radius of rotation of the floating parallel links 47, 48 about the pivot point of the grate holder 33 are made equal, and both parallel links 45,
46, 47, 48 so that the vertical displacement is offset by the rotational movement.

A lowermost wafer support plate 38 is attached to the plate holder 33.

a pivot shaft 5 fixed to one side 46 of the parallel swing links;
1 protrudes through the vertical substrate 20, and a pulley 52 is fixed to this protruding end. A reciprocating motor 54 is fixed to the anti-parallel swing link side of the vertical board 20 via a motor support fitting 53, a driving pulley 55 is fitted to the output shaft of the retracting motor 54, and the driving pulley 55 and the pulley 52
are connected by a timing belt 56.

Thus, the wafer support plate 38 can be moved forward and backward by forward and reverse rotation of the advance/retraction motor 54, and the amount of advance of the wafer support plate 38 is completely smaller than that of the upper wafer support plates 39, 40, 41, 42. It should stand out.

In the figure, 57.58 is a sensor that detects the stroke end of the floating parallel link 47.48, and 59.60 is the sensor 47.
This is a detection piece for activating 48.

The operation will be explained below.

All wafer support plates 38, 39, 40, 41.
When transferring wafers while supporting them at once using the wafer support plates 38, 39.40, 41.42,
In the figure, the position is indicated by the solid line.

Next, when performing fractional processing to transfer five or fewer wafers 1, the forward/backward motor 54 is driven and the drive pulley 55 is
, the parallel swing links 45, 46 are moved clockwise a in FIG. 2 via the timing belt 56 and pulley 52. Due to the swinging of the parallel a-moving links 45.degree. 46, the floating parallel links 47, 48 do not descend downwards, but instead rotate in a counterclockwise motion to send out the plate holster 33. When the sensor 57 detects the end of the stroke of the floating parallel link 47, 48, the forward/backward motor 54 is stopped.

Thus, only the lowest wafer support plate 38 is in a state where wafers can be transferred (indicated by the two-dot chain line in the second UjJ), and wafers can be transferred one by one.

When the rounding is completed and five wafers 1 are to be transferred at the same time again, the advancing/retracting motor 54 is driven in reverse to move the lowermost wafer support plate 38 back to the position indicated by the solid line in FIG.

Next, depending on the size of the wafers, the pitch between the wafers when storing the wafers is different. In this case, the pitch of the wafer support plates 38, 39, 40, 41, 42 is adjusted.

The pitch changing motor 31 is driven, and the screw rod 27.
Rotate 28. The rotation of the screw rond 27, 28 moves the sliders 23, 24, 25, 26 to which the plate holder is fixed.

As mentioned above, the portions where the sliders 23, 24, 25, and 26 are screwed together have different pinches at the same magnification, so the upper wafer support plate 39, 40, 41°, 42, etc., while maintaining an equal interval relationship, and the pitch is adjusted.

In the above embodiment, considering that the number of wafers stored in the wafer cassette is 25, the number of support plates was set to 5, which is a divisor of 25', or the number of support plates was may be set to 25.

Furthermore, it goes without saying that various modifications may be made without departing from the spirit of the present invention, such as using a wafer support plate that uses a vacuum suction method.

[Effects of the Invention] As described above, according to the present invention, it is possible to transfer a plurality of wafers at once or to transfer them one by one as appropriate, and the wafers can be transferred efficiently and the wafers It can be applied to any arbitrary arrangement of wafers, and even if the wafer storage pinch is changed, it can easily be handled, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part of an embodiment of the present invention ρJ;
FIG. 2 is a front perspective view of the same, FIG. 3 is an explanatory diagram showing the arrangement of wafers on a boat, and FIGS. 4 and 5 are explanatory diagrams each showing a conventional wafer transfer device. 1 is the wafer, 23.24, 25.26 are the sliders, 2
7.28 is a screw rod, 31 is a pitch change motor, 38, 39, 40, 41.42 is a wafer support plate, 44 is a forward/backward mechanism, and 54 is a forward/backward motor. Figure 4

Claims (1)

[Scope of Claims] 1) In a wafer transfer device equipped with a required number of plates for wafer transfer, at least one of the plates
A wafer transfer device characterized by being capable of moving wafers forward and backward. 2) In a wafer transfer device equipped with a required number of plates for wafer transfer, the plates except the top or bottom are connected to a pitch variable screw rod, and the threaded portion of the screw rod is A wafer transfer device characterized in that the screw pitch is changed to correspond to the position of the plate.