JP2514633B2 - Batch type wafer replacement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a diffusion device and a decompression type CV in a semiconductor manufacturing process.
The present invention relates to a batch type wafer exchanging machine for exchanging wafers for one cassette or wafers for a plurality of cassettes at the same time among wafer exchanging machines used in a wafer process such as D apparatus, and more particularly to a exchanging method thereof.

[Conventional technology]

The method of a wafer rearing machine (automatic wafer transfer device between a cassette and a boat) used in a semiconductor wafer process such as a diffusion apparatus and a decompression type CVD apparatus is roughly classified into a single wafer type and a batch rearranging method.

The single-wafer method is a method in which each groove of the boat is detected and one wafer is put into each groove, and the batch method is a method in which wafers for one cassette (25 sheets) or wafers for multiple cassettes are simultaneously replaced. So, it is now mainstream.

[Problems to be solved by the invention]

The single-wafer method has a large possibility of avoiding an operational error due to thermal deformation of the boat, but on the other hand, it takes a long time to replace the boat, which causes a large amount of dust.

In addition, since the batch type has few mechanical operations, the replacement time can be shortened, less dust is generated, and sufficiently quiet operation can be realized, but high precision machining is required for boats and the like, and further against thermal deformation of the boat due to long-term use There is no corresponding measure,
There were problems such as partial wafer tilt, minute damage to the wafer and boat, and defective operation due to the wafer being caught in the groove due to the groove position mismatch between the boat and lifter.

The present invention solves the above-mentioned problems in the batch type, relaxes the required accuracy in a new boat, and increases the allowable value of thermal deformation in a boat in use. SUMMARY OF THE INVENTION It is an object of the present invention to provide a batch type wafer replacement method capable of avoiding a malfunction due to a wafer being caught in a groove due to a mismatch between groove positions of a lifter and a lifter.

[Means for solving problems]

According to the method of the present invention, in order to solve the problems of the batch type and to achieve the above object, as shown in the drawing, a comb-shaped groove 4 for pushing up the wafer 3 from the lower portion of the cassette 1 or the boat 2.
And a wafer holding means 8 having a comb-shaped groove 6 for receiving the wafer 3 pushed up by the lifter 5 or delivering the wafer 3 to the lifter 5 in the upper part of the cassette 1 or the boat 2. In addition, in the batch type wafer exchanging machine having the high-accuracy positioning means 9 for the boat 2 or the cassette 1, the boat clamp by the high-accuracy positioning means 9 is released and the lifter 5 is moved up and down when the wafers are exchanged in the boat 2. Therefore, the wafer 3 is turned upside down.

〔Example〕

FIG. 1 is a simplified perspective view of a batch type wafer sorter according to the present invention, and FIGS. 2 and 3 are simplified cross-sectional views of a main part at the time of wafer sort by a cassette and by a boat, respectively. FIG. 5 is a simplified sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a detailed view of the boat groove portion in FIG.

First, the batch type wafer sorter according to the present invention will be described.

In the figure, 1 is a predetermined number (usually 25) of wafers 3 in each groove
A plurality of cassettes are mounted on 1a. Reference numeral 2 denotes a boat on which wafers 3 for a plurality of cassettes are placed in each groove 2a. The groove 2a of the boat 2 is Y-shaped as shown in FIG. 5, and the depth (depth of the vertical portion that actually supports the wafer) h of the groove 2a is about 1 to 2 mm.

5 is wafer 3 from the bottom of cassette 1 or boat 2
A lifter 8 having a comb-shaped groove 4 for pushing up the wafer receives the wafer 3 pushed up by the lifter 5 in the upper part of the cassette 1 or the boat 2, or the lifter 5
It is a wafer holding means (also called a clamper) with an openable / closable stopper 7 having comb-shaped grooves 6 for passing the wafer 3 to and from each other.

The lifter 5 and the wafer holding means 8 are provided in the same number as the number of the cassettes 1, and the upper and lower portions of the frame 10 are opposed to each other so that the comb-shaped grooves 4 and 6 of the cassettes 1 are aligned with each other.

The cassette 1 is positioned on a cassette moving table 11, and this table 11 can be moved by a table moving means, for example, a table feed screw 12, in the arrow direction in FIG. 1, and in the front-back direction perpendicular to the paper surface in FIG. There is.

Boat 2 is installed at Boat Home Station 14,
By means of station moving means 15, the direction of the arrow in FIG.
It can be moved in the left-right direction in the drawing, and in the direction perpendicular to the paper surface in FIG.

At the time of wafer replacement in the cassette 1, the table 11 is moved forward to move the cassette 1 to the lifter 5 and the wafer holding means 8.
Then, the table 11 is moved slightly so that the positions of the grooves 1a, 4 and 6 of the cassette 1, the lifter 5 and the wafer holding means 8 are aligned with each other.

After that, the lifter 5 is moved upward by a lifter vertical movement means, for example, a lifter vertical feed screw 13, and the wafers 3 for one cassette or a plurality of cassettes are transferred to the lifter 5, and then the wafer holding means 8 is opened and closed. To hold
Alternatively, the wafers 3 for one cassette or multiple cassettes can be transferred from the wafer holding means 8 to the lifter 5 and then transferred to the cassette 1 by lowering the lifter 5.

In addition, at the time of wafer replacement in boat 2,
14 is moved to the left to guide the boat 2 between the lifter 5 and the wafer holding means 8, and the positions of the boat 2, the lifter 5 and the grooves 2a, 4 and 6 of the wafer holding means 8 are aligned with each other. Is clamped at the station 14 by the high-precision positioning means 9.

Thereafter, similarly to the case of the cassette 1, the wafer 3 can be transferred from the boat 2 to the wafer holding means 8 or vice versa from the wafer holding means 8 to the boat 2 for one or more cassettes.

Conventionally, in such a batch type wafer sorter, the boat 2 is clamped at a fixed position by the high-precision positioning means 9 at the time of wafer sort in the boat 2, and then the plurality of lifters 5 are lifted individually or simultaneously.

According to the present invention, when the wafer is replaced by the boat 2, the boat 2
Is clamped and positioned at a fixed position by the high-precision positioning means 9, the clamp is temporarily released, and the lifters 5 are moved up and down by shifting up and down timings of the plurality of lifters 5.

In order to shift the lift timing of each lifter 5, for example, when the wafer 3 is transferred from the boat 2 to the wafer holding means 8, each lifter 5 is sequentially delayed by a predetermined time and raised, and conversely, the boat 2 is moved from the wafer holding means 8. When the wafer 3 is received, each lifter 5 may be sequentially delayed for a predetermined time and lowered.

H is a height difference based on a time difference during the ascent and descent of each lifter 5, and is set to a value sufficiently larger than the depth h of the groove 2a of the boat 2, that is, H >> h, but h is about 1 to 2 mm. Therefore, the value of H does not have to be so large and may be a very small value.

After positioning the boat 2 at a fixed position with high accuracy in this way, the clamps are released, and because the lifters 5 are moved up and down sequentially with a time lag, the lifter 5 is lifted.
When the wafer 3 in the groove 2a of the boat 2 is ejected upward by the lifter 5 or by the descending lifter 5
When the wafer 3 is put in the inside, even if a part of the boat 2 is thermally deformed, each lifter 5 and each groove 4, of the wafer holding means 8,
Even if there is a groove 2a of the boat 2 that does not correspond to 6, when the wafer 3 enters and leaves the groove 2a, the boat 2 is in the station.
Since the groove 2a of the boat 2 and the groove 4 of the lifter 5 are aligned with each other by slightly moving at 14, the groove 2a of the boat 2 and the groove 4 of the lifter 5 are aligned with the wafer 3
There is no risk of biting through.

By shifting the lift timing of each lifter 5, multiple cassettes, for example 100 sheets (4 cassettes), 150
Wafer replacement of 6 wafers (6 cassettes) is also performed in units of 1 cassette (25 wafers), so the tolerance of dimensional error required between all grooves of the boat can be increased, and the heat of the boat can be increased. It is possible to make a changer having high adaptability to deformation.

In this embodiment, the case where the lifters 5 are moved up and down sequentially with a time lag has been described, but the height position of each lifter 5 may be structurally shifted from the beginning by the H dimension.

〔The invention's effect〕

That is, according to the present invention, when the boat 2 is replaced with a new wafer, the boat 2 is clamped and positioned at a fixed position by the high-accuracy positioning means 9, the clamp is released, and the lifting timing of the lifters 5 is shifted. Each lifter 5
Since the boat 2 is moved up and down, even if a part of the boat 2 is thermally deformed, each lifter 5 and each groove of the wafer holding means 8 is deformed.
Even if there is the groove 2a of the boat 2 that does not match 4,6, when the wafer 3 moves in and out of the groove 2a, the boat 2 slightly moves on the station 14 so that the groove 2a of the boat 2 and the groove 4 of the lifter 5 are aligned. Therefore, it is possible to prevent the wafer from being caught in the groove due to the mismatch of the groove positions of the boat and the lifter.

In addition, by shifting the lifting timing of each lifter 5, the wafers for a plurality of cassettes are also rearranged sequentially in units of one cassette, so that the tolerance of the dimensional error required between all grooves of the boat is increased. Therefore, it is possible to make the changer highly responsive to the thermal deformation of the boat.

[Brief description of drawings]

FIG. 1 is a simplified perspective view of a batch type wafer exchanging machine according to the present invention, and FIGS. 2 and 3 are simplified cross-sectional views of essential parts at the time of exchanging wafers in a cassette and during exchanging wafers in a boat, respectively. 4 is a simplified sectional view taken along the line IV-IV of FIG. 3, and FIG. 5 is a detailed view of the boat groove portion of FIG. 1 ... Cassette, 1a ... Groove, 2 ... Boat, 2a ... Groove,
3 ... Wafer, 4 ... Comb groove, 5 ... Lifter, 6 ...
Comb-shaped groove, 7 ... Stopper, 8 ... Wafer holding means, 9
... High-precision positioning means.

Claims (1)

(57) [Claims] 1. A lifter having comb-shaped grooves for pushing up a wafer from a lower portion of a cassette or a boat, and a wafer for pushing up a wafer by the lifter or delivering a wafer to the lifter at an upper portion of the cassette or a boat. A batch type wafer exchanging machine, which comprises a wafer holding means having a comb-shaped groove and a highly accurate positioning means for a boat or a cassette,
A collective wafer replacement method, characterized in that when the wafer is replaced by a boat, the wafer clamp is released by raising the lifter by releasing the boat clamp by the high precision positioning means.