JPH0532904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a wafer alignment method and an alignment apparatus used for manufacturing semiconductor devices.

[Technical background of the invention and its problems] In the manufacturing of semiconductor devices, a string section (orientation flat, hereinafter abbreviated as OF) is
A heat treatment process is performed to oxidize the surface of a thin disk-shaped semiconductor wafer having a wafer and to diffuse impurities into the surface. In this process, wafers are stored in a wafer holder for heat treatment called a boat, and a large number of wafers are processed at once. But at this time
If the OFs are in different positions, the heights of the wafers on the boat will vary, and the heat treatment will not be uniform across the wafers, increasing the number of chips that will be defective. Therefore, when performing a heat treatment process, it is necessary to align the OFs of the wafers and place them on the boat.

Conventionally, this work was performed by checking the wafer with tweezers or vacuum tweezers and visually aligning the OF.

However, this method has poor workability because it is manual work, and there is also the risk of accidentally damaging the wafer during the process.

Therefore, in order to simplify this work, the present applicant has already filed Japanese Patent Application No. 1983-71683. Said invention transfers wafers from a carrier to a boat;
The work of arranging and transferring OFs is performed automatically, and the outline is as follows. A rotating shaft is embedded in a block part with a part of its circumference exposed. A wafer is placed on this rotating shaft and the rotating shaft is rotated. When the wafer is rotated, the OF can be aligned by rotating the rotating shaft for an appropriate amount of time to stop when the OF hits the block.
At this time, the wafer's positional spacing in the direction of the rotation axis is maintained by a guide placed above the rotation axis, but as the wafer rotates, the position on the rotation axis often shifts gradually. Ta. For this reason, when the wafers are placed in the boat in the next step, the wafers often do not fit smoothly into the grooves of the boat, resulting in damage to the wafers.

[Object of the Invention] The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to control the position of the wafer in the rotational axis direction so that the wafer can be smoothly transferred to the wafer holder without damaging the wafer. The purpose is to align the OF while doing so.

[Summary and Effects of the Invention] A wafer is placed on a groove provided in a rotating shaft to support the periphery of the wafer. Next, when the rotating shaft is rotated, the wafer rotates due to friction with the rotating shaft.
After a while, the OF of the wafer comes into contact with a stop mechanism arranged on the side of the rotation axis, and the rotation of the wafer is stopped, thereby aligning the wafer. At this time, since the wafers are supported by the grooves, the wafer spacing is maintained constant. Therefore, when transferring the wafer to a wafer holder or the like, the wafer is not damaged, and the transfer can be performed smoothly.

[Embodiment of the Invention] An embodiment of the present invention will be described with reference to the drawings. First, the alignment device will be explained with reference to FIGS. 1 and 2.

The boat 1 includes two cylinders 1a and 1b having a plurality of second grooves, two cylinders 1c and 1d fixed below them, and 1a, 1b to hold these four cylinders in parallel. A cylinder 1e fixed near one end of the two cylinders 1b, and two cylinders 1f and 1g fixed to the other ends of the two cylinders 1a and 1b and their vicinity.
It consists of The second grooves of the two cylinders 1a and 1b are provided at the same pitch, their positions correspond to each other, and they are inclined inward.

The boat 1 has a hollow part and is placed on a pedestal 2 having a surrounding area. A block part 3 having a flat upper part is arranged to be freely insertable and removable in the hollow part of the pedestal 2. This insertion/removal is performed by vertically moving the support rod 3a extending below the block portion 3.

A rotary shaft 4 having a plurality of first grooves is buried in the block portion 3 so that a part of its circumference is exposed. The first groove provided on the rotating shaft 4 has the same pitch as the second groove on the boat 1, and its width is narrower than the second groove width on the two cylinders 1a and 1b of the boat 1. . The degree of embedding is such that the top of the first groove of the rotating shaft 4 is slightly above the upper surface of the block part 3.

Two cylinders 1 with a second groove of the boat
Two guides 5 and 6 each having a third groove for holding the circumferential portion of the wafer are provided above each of guides 5 and 1b. two guides 5, 6
are horizontally movable so that their spacing can be changed. Also, the third groove provided in these has the same pitch as the second groove of the boat 1, and the two guides are arranged so that the position of the third groove corresponds to the first groove of the rotating shaft. 5,6
is placed.

Note that the power parts of the support rod 3a and the two guides 5 and 6 are omitted.

Next, the operation will be explained using FIGS. 2, 3, and 4.

First, the boat 1 is fixed so that the second groove of the boat 1 attached to the pedestal 2 corresponds to the first groove of the rotating shaft 4 embedded in the block part 3. The upper surface of the rotating shaft 4 is located at almost the same height as the upper end of the boat 1. Two more guides 5,
6 is the appropriate spacing to hold the wafer.

Next, the wafer is inserted into each third groove of the two guides 5, 6 at corresponding positions. Then, the wafer is guided into the third groove of the guide and is placed in the first groove of the rotating shaft 4 at the corresponding position. (Figure 2) Note that the position of OF8 at this time is uncertain. Further, when the OF 8 is not on the rotation axis, the block part 3 is arranged so that the wafer and the block part 3 do not come into contact with each other.

Next, the rotating shaft 4 is rotated, for example, clockwise in FIG. 2. Then, the wafer 7 starts to rotate counterclockwise due to the frictional force with the first groove of the rotating shaft 4. After a while, the OF end 8a moves to the rotating shaft 4.
After that, the OF end 8b hits the block part 3, and the wafer 7 stops rotating. (FIG. 3) In other words, the block portion 3 functions as a stopping mechanism. Also, the rotating shaft 4 continues to rotate after this, and the OF of all wafers is
Rotate until the end 8b hits the block part 3 and stops rotating. Then, after a predetermined period of time has elapsed, the rotation of the rotating shaft 4 is stopped. It is sufficient that the rotation shaft 4 is rotated for 1.5 rotations of a disk having the same diameter as the wafer 7. If you do this,
In the state shown in FIG. 2, no matter where the OF8 is located on the wafer, when the rotation of the rotating shaft 4 stops, the OF8 will be aligned as shown in FIG. During the operation of aligning the OF 8, the position of the wafer 7 in the direction of the rotation axis does not shift because the rotation axis 4 is provided with the first groove, and is maintained at a predetermined position.

Next, the block part 3 is slowly lowered. Since the wafer 7 is supported by the block part 3 and the rotating shaft 4, it descends as the block part 3 descends. Eventually, the circumference of the wafer 7 enters the two guides 5 and 6, the third groove of the rotating shaft 4, and the second groove of the boat 1 at a position corresponding to the first groove, and the wafer 7 enters the block portion 3. Then, it is separated from the support by the rotating shaft 4 and comes to be supported by the boat 1. At this time, since the width of the first groove of the rotating shaft is narrower than that of the second groove of the boat, the wafer is smoothly accommodated in the second groove of the boat. (FIG. 4) Finally, the guides 5 and 6 are moved horizontally to widen the gap between them, and the boat 1 is taken out.

In the embodiment described above, a block portion was used as the stopping mechanism, but in addition to this, a bar may be disposed on the side of the rotating shaft in parallel with the rotating shaft to serve as the stopping mechanism.
It is also possible to drive the pedestal and store the wafers in the boat.

Furthermore, although the embodiment described above was for aligning a plurality of wafers at once, this can easily be applied to an apparatus that handles only one wafer.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a device according to an embodiment of the present invention, and FIGS.
-A' sectional view. 1...boat, 2...cradle, 3...block, 3a...support rod, 5...guide, 6...guide, 7...wafer, 8...OF.

Claims (1)

[Scope of Claims] 1. The upper surface of a rotating shaft having a plurality of first grooves embedded in a vertically movable stop mechanism and formed at a constant pitch, at the same pitch as the first grooves,
The wafer holder is positioned at approximately the same height as the upper end of the wafer holder having a second groove formed with a groove width greater than or equal to the first groove width, and a second groove formed at the same pitch as the first groove. A guide having three grooves for holding the circumference of the wafer is positioned above the wafer holder, and the first groove, second groove and third groove are arranged to correspond to each other. Inserting a thin disc-shaped wafer having a chord part in a part into the third groove of the guide and the first groove of the rotating shaft, and positioning the wafer in the direction of the guide and the rotating shaft. a step of supporting the wafer; a step of rotating the wafer by rotating the rotation shaft so that a circumferential portion of the wafer contacts a first groove of the rotation shaft; stopping the rotation of the wafer when the wafer passes through and comes into contact with the top surface of the stop mechanism; thereafter, stopping the rotation of the rotation shaft; and removing the stop mechanism and the rotation shaft from the wafer, and the rotation of the wafer is stopped. A wafer alignment method comprising the step of inserting a peripheral portion into a second groove of the wafer holder and holding the wafer by the guide and the wafer holder. 2. A vertically movable rotating shaft having a plurality of first grooves formed at a constant pitch for supporting a plurality of thin disc-shaped wafers each having a chord part; and a side of the rotating shaft. When the chord part of the wafer passes through the rotation axis and comes into contact with the upper surface of the wafer,
a vertically movable stop mechanism that stops the rotation; and a stop mechanism disposed on the side of the stop mechanism, the groove width being formed at the same pitch as the first groove of the rotating shaft and having a groove width greater than or equal to the first groove width. , and a wafer holder having a second groove corresponding to the first groove; a guide having a third groove corresponding to the groove and for holding the circumferential portion of the wafer; and a guide having a third groove for holding the circumferential portion of the wafer; and the rotation shaft and a stop mechanism for storing the wafer supported on the rotation shaft in a wafer holder. A wafer alignment device comprising: a drive mechanism that changes the positional relationship of the wafers; 3. The wafer alignment according to claim 2, wherein a block portion having a recessed portion and a rotating shaft embedded in the recessed portion with a part of its circumference exposed is used as a stopping mechanism. Device.