JPH0568102B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wafer transfer method.

[Prior Art] As is well known, semiconductor devices are manufactured through a number of steps such as thermal oxidation treatment, impurity diffusion treatment, film deposition treatment, and etching treatment on a wafer that is cut from an ingot and subjected to surface treatment. has been done. For example, in a film deposition process, multiple jigs (such as carriers) containing multiple wafers that have been processed in the previous process are prepared, and the wafers in these carriers are moved to another jig for film deposition. After transferring to a quartz boat (for example, a quartz boat), this quartz boat is transported into a heat treatment furnace, and while maintaining the inside of the furnace at a predetermined temperature, various reaction gases are supplied to each A method is adopted in which a predetermined film is deposited on the wafer surface.

The method of transferring wafers to the quartz boat mentioned above is usually by inserting the wafers into a plurality of grooves vertically cut into two or four support rods of the quartz boat (for example, the method of 54-34774, JP-A-54-19673, JP-A-60-19656, etc.). On the other hand, recently, a method has been used in which a plurality of grooves are cut in the support rod of a quartz boat at a desired angle to the vertical direction, and wafers are inserted into these grooves to stand up. If the wafers are placed on the boat at an angle like this, when the quartz boat is transported into the heat treatment furnace and various reaction gases are supplied while maintaining the furnace interior at a predetermined temperature, the gases will flow onto the surface of each wafer. Even if the groove shape of the boat changes due to repeated use, the inclination direction of adjacent wafers remains the same as when the grooves are cut vertically. This has advantages such as being able to maintain the inclination direction in a constant direction while avoiding variations in the angle.

By the way, as a device for transferring wafers into a plurality of grooves cut obliquely into the support rod of the quartz boat mentioned above, the device disclosed in Japanese Utility Model Application No. 136543/1983 is known. This transfer device includes a pushing member that pushes up a plurality of wafers in a carrier, a wafer chuck that can move up and down and can be opened and closed to hold the plurality of wafers pushed up by the pushing member, and a wafer chuck that holds the plurality of wafers pushed up by the push-up member, and It consists of an inclined mounting table that is vertically movable and onto which the wafers are transferred.

[Problems to be Solved by the Invention] However, in the above-mentioned transfer device, the mount on which the wafer is transferred moves up and down, so when transferring wafers from a plurality of carriers to the mount,
In the second and subsequent transfer operations, the wafers that have already been propped up are affected by vibrations when the mount moves in the vertical direction. Moreover, when transferring multiple wafers held in a wafer chuck to a mounting table,
Since it is necessary to insert the mount between the wafer chucks, the width of the mount is restricted. As a result, it becomes difficult to stably transfer the wafer to the mount. Therefore, due to the effect of vibration on wafers already placed on the wafer due to the vertical movement of the mount, and the instability of wafer retention due to the width constraints of the mount, wafers may fall off or be adjacent to each other during transfer operations. There were problems such as damage caused by contact between wafers.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to stably transfer a plurality of wafers housed in a first jig such as a carrier into an inclined groove of a second jig such as a quartz boat. The purpose is to provide a wafer transfer method that can transfer wafers.

[Means for Solving the Problems] The present invention moves a plurality of wafers stored in a first jig to a second jig in which a plurality of grooves are cut at a desired angle with respect to the vertical direction. In the transfer method, the plurality of wafers in the first jig are sequentially moved from one end side to the other end side by a wafer chuck so that the lower end of each wafer is placed at an angle corresponding to the inclination angle of the groove with respect to the horizontal direction. the wafer chuck is moved above the second jig which is tilted and fixed so that the grooves are oriented in the vertical direction, and the wafer chuck is lowered to place each wafer in the wafer chuck in the second jig. The method is characterized by comprising a step of leaning the jigs against the grooves of the two jigs, respectively.

[Function] According to the present invention, the plurality of wafers in the first jig are sequentially moved from one end side to the other end side by wafer chucking, and the lower end of each wafer is sequentially bent at an angle corresponding to the inclination angle of the groove with respect to the horizontal direction. Then, the wafer chuck is held above the second jig, which is tilted and fixed so that the grooves are oriented vertically, and the wafer chuck is lowered to remove each wafer in the wafer chuck. By leaning the wafers against the grooves of the second jig, the plurality of wafers in the first jig can be stably transferred to the inclined grooves of the second jig. Moreover, even in the second and subsequent wafer transfer operations, the wafers that have already been transferred to the second jig can be stably transferred without being affected by vibrations.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 in FIG. 1 is a box-shaped housing. A carrier stage 2 and a boat stage 3 are provided on the housing 1 so as to be located on the same line. Further, an operation panel 4 is provided on the side wall of the housing 1 in parallel.

As shown in FIGS. 4A to 4D, the carrier stage 2 has holes 5 for projecting and retracting a push-up plate of a push-up mechanism, which will be described later, corresponding to the carriers to be placed thereon. Furthermore, a pair of boat support members 6a and 6b are erected on the boat stage 3 with a predetermined interval therebetween. These boat support members 6
a and 6b indicate the angle of inclination between the tops of the support member 6.
It is set to correspond to the inclination angle (Θ) of the quartz boat groove to be placed on points a and 6b.

Said carrier stage 2 and boat stage 3
An elongated hole 7 is formed in the housing 1 on the nearer side. Below the elongated hole 7, two guide shafts 8a and 8b are arranged parallel to each other, as shown in FIG. A sliding table 9 is placed on these guide shafts 8a and 8b. An engagement plate 10 is erected on the table 9, and the guide shaft 8a,
A ball screw 11 arranged parallel to 8b is screwed together. One end of this boat screw 11 is pivotally supported by a support plate 12, and the other end is connected to a pulse motor 13. This motor 13 is connected to a motor drive circuit 14, and the drive circuit 14 is connected to a control circuit 15. That is, by outputting a predetermined signal from the control circuit 15 to the drive circuit 14, the pulse motor 13 is driven, and the motor 1
The ball screw 11 connected to 3 rotates. Due to the rotation of the ball screw 11, the sliding table 9, which is engaged with the ball screw 11 via the engagement plate 10, moves 2
The book moves along guide rails 8a and 8b.

A push-up mechanism 16 is provided on the table 9. This thrusting mechanism 16 includes a first cylinder 18 having a piston 17 that moves up and down.
A push-up plate 19 is attached to the upper end of the piston 17, and has a plurality of arcuate grooves formed therein that extend and retract through the hole 5 of the carrier stage 2 as the piston 17 moves up and down. Also,
A second cylinder 2 having a pair of pistons 20a and 20b that moves up and down is disposed above the table 9.
1 is provided. These pistons 20a,
At the tip of 20b, a chuck drive mechanism 22 is provided as shown in FIG. This drive mechanism 22
The main body 2 has four actuating shafts 24a to 24d that extend horizontally from the main body 23 and can freely move forward and backward.
Each of the operating shafts 24a, 24b and 24 is provided at the rear end of each operating shaft 24a to 24d located within the
It consists of a gear system (not shown) that drives the gears c and 24d in opposite directions, and a motor (not shown) that rotates this gear system. A wafer chuck 25 is attached to the chuck drive mechanism 22. This wafer chuck 25 includes a pair of opening/closing plates 26a, which are arranged parallel to each other and facing each other.
26b. One opening/closing plate 26a located on the side closer to the main body 23 has a lower surface at the tips of two of the four operating shafts 24a to 24d (for example, 24a and 24b) that operate in the same direction, with the lower surface facing the horizontal direction. It is supported at an angle Θ. Further, the other opening/closing plate 24b is connected to the one opening/closing plate 24b.
The remaining two operating shafts 24c and 24d, which pass through the shaft a and move in the same direction, are supported at their tips with their lower surfaces inclined at an angle Θ with respect to the horizontal direction. Holding portions 27a and 2 for holding wafers are provided on the inner surfaces of the opening and closing plates 26a and 26b from near the center to the lower ends, respectively.
7b is attached, and these holding parts 27
A plurality of claws extending from the upper end to the lower end are formed on the inner surfaces of a and 27b in the width direction thereof. In such a chuck drive mechanism 22, when the motor of the drive mechanism 22 is operated, the two operating shafts 24a and 24b that support the opening/closing plate 26a of the wafer chuck 25 on the side closer to the main body 23 move backward, and support the other opening/closing plate 26b. The two operating shafts 24c and 24d move forward, and the pair of opening/closing plates 26a and 26b are opened. Also, when the operating shafts 24a, 24b, 24c, 24d supporting the respective opening/closing plates 26a, 26b are moved in the opposite direction, the pair of opening/closing plates 26
a, 26b are closed. Note that the pulse motor 13, the first and second pulse motors that rotate the ball screw 11,
cylinders 18, 21 and chuck drive mechanism 22
is operated at the timing necessary for the transfer by a programming signal from a control device (not shown) provided on the operation panel 4.

Next, a wafer transfer method will be explained with reference to the aforementioned FIGS. 1 to 4 and FIGS. 5 to 8.

() First, as shown in FIGS. 1 and 6, for example, four carriers 29a to 29d, each serving as a first jig containing a plurality of wafers 28, are installed at predetermined positions on the carrier stage 2. . In addition, the quartz boat 30 in which a plurality of grooves (not shown) that are inclined at a predetermined angle (Θ) with respect to the vertical direction are cut is transferred to a boat support member with different heights of the boat stage 3 by a transport device (not shown). 6
a, 6b. At this time, since the inclination angle between the tops of the boat support members 6a and 6b is set to correspond to the inclination angle (Θ) of the groove, the groove of the installed quartz boat 30 is positioned so that it faces vertically. be done.

() Next, the control circuit 15 outputs a predetermined signal to the drive circuit 14 to rotate the pulse motor 13 for a predetermined period of time, thereby rotating the ball screw 11 connected to the motor 13. As a result, the sliding table 9, which is engaged with the ball screw 11 through the engagement plate 10, is moved along the guide shafts 8a and 8b, and is supported by the table 9 through the second cylinder 21, chuck drive mechanism 22, etc. The fixed wafer chuck 25 is transferred to the first carrier 29a.
(as shown in Figure 4A).

Next, the motor of the chuck drive mechanism 22 is rotated to move back the two operating shafts 24a and 24b that support the opening/closing plate 26a on the side of the wafer chuck 25 closer to the driving mechanism 22, and supporting the other opening/closing plate 26b. Two operating shafts 24c, 2
4d is advanced to open and close the pair of opening/closing plates 26a, 26b.
open. Next, the first cylinder 18 of the push-up mechanism 16 is driven to raise the piston 17, and the push-up plate 19 attached to the tip of the piston 17 is
to rise. As a result, the push-up plate 19 passes through the hole 5 of the carrier stage 2, receives the plurality of wafers 28 stored in the carrier 29a within the arc-shaped groove at its upper part, and lifts each wafer 28 together with the push-up plate 19 into the open wafer chuck. 25 (as shown in FIG. 4B).

Next, the motor of the chuck drive mechanism 22 is rotated in the opposite direction to the above, and the opening/closing plate 26a of the wafer chuck 25 on the side closer to the drive mechanism 22 is rotated.
The two operating shafts 24a, 24b supporting the other opening/closing plate 26b are moved forward, and the two operating shafts 24c, 24d supporting the other opening/closing plate 26b are retreated to close the pair of opening/closing plates 26a, 26b (as shown in FIG. 4C). ). Next, the first cylinder 1 of the thrusting mechanism 16
8 to lower the piston 17, and lower the push-up plate 19 attached to the tip of the piston 17. When the push-up plate 19 descends between the closed opening/closing plates 26a, 26b of the wafer chuck 25, the wafer 28 received by the pushing up plate 19 is moved by the claws formed on the holding parts 27a, 27b of the opening/closing plates 26a, 26b. Engaged in the valley. At this time, since the lower surfaces of the opening/closing plates 26a and 26b are inclined at an angle of Θ with respect to the horizontal line, each wafer 28 is sequentially engaged and transferred from between the claws on the upper side of the holding parts 27a and 27b. , each wafer 28 is connected to the wafer chuck 24 as shown in FIGS. 4D and 5.
Accordingly, the lower ends of the wafers 28 are held so as to be located at an angle (Θ) corresponding to the inclination angle of the groove of the boat 30 with respect to the horizontal line from one end to the other.

() Next, the second cylinder 21 is driven to raise the pistons 20a, 20b and lift the wafer chuck 25 supported by the chuck drive mechanism 22 to a predetermined position (as shown in FIG. 6). Next, a predetermined signal is output from the control circuit 15 to the drive circuit 14 to rotate the pulse motor 13 for a predetermined time, and the ball screw 1 connected to the motor 13 is rotated.
1, the sliding table 9 engaged with the ball screw 11 via the engagement plate 10 is moved along the guide shafts 8a, 8b, and the second cylinder 21, chuck drive mechanism 22, etc. are attached to the table 9. The wafer chuck 25 supported and fixed via the quartz boat 30 is positioned directly above the front stage side of the quartz boat 30 (X _A in FIG. 7). After this, the second
pistons 20a, 2 by driving the cylinder 21 of
The wafer chuck 25 supported by the carrier drive mechanism 22 is shown in _FIG.
lower it to the position. As a result, each wafer 28 held in the chuck 25 is engaged with the groove of the quartz boat 30 inclined at an angle (Θ) with respect to the horizontal line, and the wafers 28 are transferred. At this time, since the quartz boat 30 is fixed and only the wafer chuck 25 moves up and down, the width of the quartz boat 30 is not restricted in relation to the wafer chuck 25, and a sufficiently wide quartz boat 30 can be used.
The transferred wafer 28 can be stably held in the quartz boat 30.

() Next, after the wafer transfer operation in the first carrier 29a is completed, the second cylinder 29a is transferred to the second cylinder 29a.
The wafer chuck 25 is raised by the first piston 20a, 20b, moved to the table 9 by the rotation of the pulse motor 13, the wafer chuck 25 is moved onto the second carrier 29b, and the wafer chuck 25 is lowered by the second cylinder 21 piston 20a, 20b. Then, preparations are made for transferring the wafer 28 into the second carrier. Subsequently, in a process similar to the above (), the plurality of wafers 28 in the second carrier 29b are moved by the wafer chuck 24 so that the lower end of each wafer 28 is moved from one end to the other, and the grooves of the boat 30 are successively aligned with the horizontal line. It is held so that it is positioned at an angle (Θ) corresponding to the inclination angle. After this, the same process as in () above (however, the position of the wafer chuck 25 on the quartz boat 30 is shown in FIG. 7).
_XB , the lowering position to the boat 30 is _ZB in FIG. and perform the transfer. At this time, since the quartz boat 30 is fixed to the boat support members 6a and 6b, it is possible to avoid the influence of vibrations on the wafers 25 already placed on the boat 30 due to the first transfer operation.

Next, the third and fourth carrier 29c,
By performing the same operation on the wafer 28 stored in the wafer 29d, the four carriers 2
The transfer is performed by engaging all of the wafers 28 in 9a to 29d with the grooves of the quartz boat 30 inclined at an angle (Θ) with respect to the horizontal line. However, when transferring the wafer 28 in the third carrier 29c, the wafer chuck 25 is transferred onto the quartz boat 30.
The position of is X _C shown in FIG. 7, and the lowering position to the boat 30 is Z _C shown in FIG. In addition, in transferring the wafer 28 in the fourth carrier 29d,
The position of the wafer chuck 25 on the quartz boat 30 is X _D shown in FIG. 7, and the position of the wafer chuck 25 lowered onto the boat 30 is Z _D in FIG. After performing such a transfer operation, the quartz boat 30 is placed horizontally so that each transferred wafer 28 is placed at an angle (Θ) with respect to the vertical direction of the boat 30 as shown in FIG. ) so that it can be propped up at an angle.

[Effects of the Invention] As detailed above, according to the wafer transfer method of the present invention, the width of the second jig is not limited by the relationship with the wafer chuck, and a plurality of wafers in the first jig can be transferred. It can be stably transferred to the inclined groove of the second jig,
Moreover, in the second and subsequent wafer transfer operations from the first jig to the second jig, it is possible to avoid the effects of vibration on the wafers that have already been transferred to the second jig, so that the various effects listed below can be achieved. I can demonstrate it.

Damage caused by falling of the wafer from the second jig or contact between adjacent wafers during the transfer operation can be prevented. In particular, when transferring one wafer from a plurality of first jigs to a second jig, wafers may fall off or adjacent wafers may fall off during the second and subsequent transfers from the first jig to the second jig. Damage caused by contact between the two can be effectively prevented.

Even if the wafer has a large diameter, it can be stably transferred to the second jig.

Due to the above action, when the quartz boat serving as the second jig is transported into the heat treatment furnace and various reaction gases are supplied while maintaining the predetermined temperature inside the furnace, the gas flows uniformly over the surface of each wafer. This makes it possible to perform processes such as film deposition with uniform thickness. Even if the groove shape of the boat changes due to repeated use, it is possible to maintain the inclination direction in a constant direction without causing the inclination directions of adjacent wafers to vary, which would occur if the grooves were cut vertically.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one form of a wafer transfer apparatus used in the wafer transfer method of the present invention, FIG. 2 is a perspective view showing main parts of the transfer apparatus shown in FIG. 1, and FIG. 2 is an enlarged perspective view of the chuck mechanism and wafer chuck; FIGS. 4A to 4D are schematic diagrams showing intermediate steps of wafer transfer; FIG. 5 is a view taken in the direction of arrow A in FIG. 4D;
FIG. 6 is a schematic diagram showing the state in which wafers are transferred to a quartz boat using a wafer chuck, FIG. 7 is a schematic diagram showing the position of the wafer chuck when wafers are transferred to a quartz boat by a wafer chuck, and FIG. 1 is a schematic diagram showing a quartz boat installed in a horizontal state after wafer transfer and a wafer tilted up against the boat; FIG. 1... Housing, 2... Carrier stage,
3... Boat stage, 6a, 6b... Boat support member, 9... Sliding table, 13... Pulse motor, 17... Pushing up mechanism, 19... Pushing up plate,
22...Chuck drive mechanism, 24a to 24d...
Operating axis, 25... Wafer chuck, 26a, 26
b... Opening/closing plate, 27a, 27b... Holding part, 28
...Wafer, 29a-29d...Carrier (first
jig), 30...quartz boat (second jig).

Claims (1)

[Scope of Claims] 1. A method for transferring a plurality of wafers stored in a first jig to a second jig in which a plurality of grooves are cut at a desired angle with respect to the vertical direction. A step of holding a plurality of wafers in the first jig using a wafer hitch so that the lower ends of each wafer are sequentially positioned at an angle corresponding to the inclination angle of the groove with respect to the horizontal direction from one end side to the other end side. Then, the wafer chuck is moved above the second jig fixed at an angle so that the grooves are oriented vertically, and the wafer chuck is lowered to place each wafer in the wafer chuck into the grooves of the second jig. A wafer transfer method characterized by comprising a step of standing the wafer upright. 2. The wafer chuck is capable of vertical movement and opening/closing, and is provided with a pair of opening/closing plates whose lower surfaces are inclined with respect to the horizontal direction at an angle corresponding to the inclination angle of the groove of the second jig, and the inner surfaces of these opening/closing plates, 2. The wafer transfer method according to claim 1, further comprising a holding portion having a plurality of claws extending in the width direction from the upper end to the lower end.