JPH04157753A - Surface treatment device - Google Patents

Abstract

PURPOSE:To enable a wafer to be transferred in order without generating an empty rack at each rack of a boat even if a wafer cassette is not full or wafers and hence there are empty racks by padding the wafers into the racks of the boat starting from the first rack in a transfer sequence from the wafer cassette to the boat. CONSTITUTION:When a start command of sequence is generated, a vacuum suction pen 19A approaches No.1 rack at a first stage of a wafer cassette 21 from the waiting position P10, moves a path of points P10-P11-P12, checks to see of there are wafers in this rack while moving between P11 and P12 with a sensor 53, performs vacuum suction of a wafer W1 if it exists, and then moves a path P12-P13-P14-P24. When the vacuum suction pen 19A reaches immediate before the point P13, non-suction state is switched on, and the wafer W1 is transferred to the No.1 rack of the boat 17. When this transfer cycle ends, the vacuum suction pen 19A moves from P24 to P20, and then approaches the No.2 rack of a wafer cassette 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface treatment apparatus for surface treatment of semiconductor wafers.

[Prior art] Fig. 6 shows a system for performing surface treatment of the type disclosed in, for example, Japanese Patent Application Laid-Open No. 63-239938, in which 10 is a vertical reactor, 11 is a furnace shutter ζ12
is a boat elevator, and the reactor 10 is equipped with a furnace body 13, a heater 14, a quartz tube 15, and a support flange 16 as shown in FIG. body) is supplied. 17 is a semiconductor wafer W1. to be subjected to CVD processing. This is a boat that holds a large number of dummy wafers W and filler wafers WF in stages, and is transferred by a transfer device 18 to a boat support stand 12B on an elevating table 12A of a boat elevator 12.

The semiconductor wafers Wp are stored in a wafer cassette 21 as shown in FIG. Dummy wafers WD and filler wafers WF are replaced after their service life has elapsed.
The same is true.

Below, semiconductor wafer W and dummy wafer W! 1 and filler wafer W are collectively referred to as wafer W.

This boat 17, as shown in FIGS. 9 and 10,
Between the upper plate 17A and the lower plate 17B, there are four shelf posts 22 to 2.
Each of the shelf pillars 22 to 25 has recesses 26 on which the peripheral portions of wafers are placed, which are spaced apart from each other at regular intervals in the vertical direction.

Each wafer is transferred to the cassette 21 with a robot finger (spatula-shaped vacuum suction pen 19A) attached to the transfer robot 19.
The wafers are taken out one by one and carried into the boat 17 in the direction of the arrow in FIG. (becomes a shelf) 26.

This transfer operation, that is, from the wafer cassette 21 to the boat 1
The transfer sequence for transferring the wafer to No. 7 will be described below.

When a command to start this transfer sequence is issued, the vacuum suction pen 19A approaches the fence of shelf number 1 in the first stage of the wafer cassette 21 from its standby position P+o, and moves to points P, -P, . - Move along the path of P, □, PlL
While moving Plt, this wafer W is vacuum-suctioned and lifted from the shelf, and as it is, P I Pt3 P
t4 Move along the route of Pt4. Vacuum suction pen 19A
When the wafer W reaches just before the point pus, it is switched to the non-suction state, and while the ptz Pt4 is being moved, the wafer W is placed on the shelf No. 1 of the boat 17 (semiconductor wafer W).
It is placed on the top shelf of a multi-tiered shelf that stores p.

When this transfer cycle is finished, the vacuum suction pen 19A
P7. From there, head toward P2° and approach the shelf number 2 of the wafer cassette 21. Similar to above,
The vacuum suction pen 19A moves along the path pto pit-Pt2. There are no wafers on this shelf, but the vacuum suction pen 19A can be used without stopping the transfer cycle.
Move along the path of tz Pz+ Pt4 Psa.

Therefore, the transfer cycle is executed, but the shelf number 2 of the boat 17 is left blank.Next, the vacuum suction pen 19A is moved to P34-P. - While moving along the path of PHI P3g and moving P31 psi as before, vacuum suction the wafer Wz, lift it from the shelf, and move to P3! The wafer Wt is transferred to the shelf No. 3 of the boat 17 by moving along the path Pss P31 P44.

[Problem to be solved by the invention]

As described above (conventionally, even if the shelf of the wafer cassette 21 that the vacuum suction ben 19A approaches is empty, the transfer cycle is executed, and if the wafer cassette 21 is empty, the boat 17 is also Since there are blank spaces, the spacing between the wafers within the board 17 becomes uneven, resulting in uneven processing.

The present invention has been made to solve this problem, and regardless of whether or not there is a blank space in the wafer cassette, wafers can be transferred to a boat without creating a blank space, and the yield is increased compared to the conventional method. The purpose of the present invention is to provide a surface treatment device that can perform the following steps.

[Means to solve the problem]

In order to achieve the above object, the present invention provides that in the sequence of transferring a wafer cassette to a boat, if there are no wafers on the shelf of the approached wafer cassette, the transfer cycle is stopped and the next step is carried out. When a wafer is approached on the shelf of the tier, and there is a wafer on the approached fence, the transfer cycle is continuously executed, and in the invention of claim 1, the control section that controls the transfer sequence has a control unit that controls each column of the wafer cassette. In the transfer sequence from a wafer cassette to a boat, if there are no wafers on the shelf of the approaching wafer cassette, the column of the shelf number of the fence in question is written in the above table. Write "No", stop the transfer cycle, approach the next column, and if there are wafers on the shelf you approach, write "Yes" in the shelf number column of the shelf in the table above and move the In the sequence where the loading cycle is continued and the wafers are transferred back from the boat to the wafer cassette, if the table above is accessed and the value in the column of the accessed shelf number is "Yes", this shelf is When the transfer robot executes the return transfer cycle with the shelf number specified as the wafer return destination, and the value in this column is "None",
The configuration is such that the return transfer cycle is stopped, the next shelf number column is accessed, and this is repeated until the column with the value "Yes" is accessed.

[Effect]

In the present invention, in the transfer sequence from the wafer cassette to the boat, the boat column is filled with wafers first, so even if the wafer cassette is not full of wafers and there are blank columns, each column of the boat is sequentially filled with wafers. The wafers are transferred without any blank spaces.

In addition, a table is provided in which the seed information (presence or absence of wafers) of the wafer cassette is written, and in the sequence of transferring wafers back from the boat to the wafer cassette, this table is accessed and In order of
Returning the wafers from the boat ensures that each wafer is returned to its original shelf in the wafer cassette.

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

In FIG. 1, 50 is a sequencer, 51 is a control device for the mobile robot 19 that operates based on commands from the sequencer, 52 is a main body of the mobile robot 19, and 53 is a sensor provided on the vacuum suction ben 19A. It has a built-in table memory (backup memory, DRAM) 50A having a table as shown in FIG.

FIG. 2 shows the path of the vacuum suction ben 19A of the mobile robot 19 when it approaches the shelf of the wafer cassette 21 and transfers the wafer to the column of the boat 17.

Here, for ease of understanding and convenience of explanation,
The path of the vacuum suction ben 19A is shown assuming that wafers are sequentially taken out from the upper shelf of the wafer cassette 21 and transferred sequentially from the upper rail of the boat 17 to the lower shelf.

Figure 4 is a flowchart of the transfer program executed in the sequence of transferring wafers from the wafer cassette to the boat, and Figure 5 is a flowchart of the transfer program executed in the sequence of transferring wafers from the boat to the wafer cassette. be.

Next, the wafer transfer operation will be explained.

(1) Transfer sequence from wafer cassette to boat When this sequence start command is issued, vacuum suction vent 1
9A is the wafer cassette 21 from its standby position PL (l).
Approach the shelf number No. 1 column in the first row of
Move the path of point P1゜-PlI Pit and move to PlI
While moving the PHI, the sensor 53 checks whether there is a wafer on this shelf or not. In this example, there is a wafer Wl, so wafer W1 is vacuum-suctioned, lifted from the column, and then transferred to the ptg P+3-P+4 pin. Move along the route. When the vacuum suction vent 19A reaches just before point PI3, it is switched to a non-suction state and PI3 P
While the wafer Wl is being moved from +4, the wafer Wl is placed on the shelf No. 1 of the boat 17. When the sensor 53 detects a wafer, "1" is written in the shelf number N001 column of the table shown in FIG.

When this transfer cycle is finished, the vacuum suction ben 19A
From F'za, head toward P2° and approach the shelf number 2 of the wafer cassette 21. Similar to above,
Vacuum suction Ben 19A is P! . -While moving along the path of PHI-ptz and moving PHI-ptg, the sensor 53 checks whether there are any wafers on this shelf. Since there are no wafers on this fence, the vacuum suction ben 19A stops the transfer operation, descends from P2□ to P□, and P! . From P
,. the shelf number N of the wafer cassette 21.
o. Start approaching the 3rd shelf. Here, since the sensor 53 does not detect a wafer, "0" is written in the shelf number No. 2 column of the table in FIG.

Next, the vacuum suction ben 19A moves to point P. -P31Pa
Pl1. While moving p3g, the sensor 53 checks whether there is a wafer in this column, and in this example, wafer W! Since there is
This wafer W2 is lifted from the shelf by vacuum suction and moved as it is along the path PSm F'+APt4P23 P+4. When the vacuum suction pen 19A reaches just before point PR3, it is switched to the non-suction state and Pzs PI4
While moving the wafers Wt to the shelf number N0 of the boat 17
It is placed on shelf 02. Since there are wafers here, "1" is written in the shelf number No. 3 column of the table in FIG. 3.

After this, the vacuum suction ben 19A is moved to P2. From there, go to P4° via Pa4 and check the shelf number of wafer cassette 21.
, Approach the 4th shelf. The wafer W on the shelf No. 4 is transferred to the shelf No. N003 of the boat 17.

When the vacuum suction ben 19A approaches the shelf No. 6, there are no wafers on this shelf, so "0" is written in the shelf No. 6 column of the table above, and the vacuum suction ben 19A After stopping the transfer operation and moving from Pa1 to Pl as shown in Fig. 3, from Pth to P
,. Return to P. Move to and start approaching shelf number 7. There are no wafers on this shelf either, so the shelf number on the table above.

"0" is written in the column 7, and the vacuum suction ben 19A is
After stopping the transfer operation and moving from P'rt to pin, P? l to P. Return to P@. Move to and start approaching shelf number 8. Shelf number N
Since there is a wafer W on the shelf No. o, 8, "1" is written in the shelf number No. 8 column of the table above, and the vacuum gripping ben 19A is PHI PaA PSm-ps.
3 Move the wafer WS along the path of Pa4 to boat 17.
Transfer to shelf number 5.

Thereafter, similar operations are repeated a number of times equal to the number of shelves of the wafer cassettes 21, and the sequence of transferring the wafers in the wafer cassettes 21 to the boat 17 is completed.

In this way, the shelves of the boat 17 are filled with wafers first, so even if there is a blank space in the wafer cassette 21, there will be no blank space in the boat 17.

(2) Transfer sequence from boat to wafer cassette When the start command for this sequence occurs, the shelf number 1 column of the table in Figure 3 is accessed.Currently, the value of this column is "1". Therefore, the transfer robot 19 is designated as the shelf with the shelf number of the wafer cassette 21 as the wafer return destination, and the vacuum suction ben 19A is designated as the shelf number N of the boat 17.
o. Have them approach the 1st shelf. vacuum suction ben 19
A is pto P14P13 Ptz P++
P+. The wafer Wl is returned to the fence of shelf number N001 of the wafer cassette 21 and transferred.

When this return transfer cycle is completed, the shelf number No. 32 column in the table of FIG. 3 is accessed. Since the value of this column is now "0", the return transfer operation is stopped, and then the column of shelf number N013 of the table is accessed.

Since the value in this column is "IJ," the transfer robot 19 is designated as the shelf with the relevant shelf number of the wafer cassette 21 as the wafer return destination, and approaches the fence of the boat 17 with the shelf number No. 2 with the vacuum suction ben 19A. Vacuum adsorption ben 19
A is the path shown by the double arrow in FIG.
pzaPsi Pta PsAP3z P3+
The path of P2O is changed to [1], and the wafer W2 is returned to the shelf No. 3 of the wafer cassette 21 and transferred.

When this return transfer cycle is completed, the shelf number N094 column of the table in Figure 3 is accessed, and the value of this column is "1".
” Therefore, the vacuum suction ben 19A specifies this shelf as the wafer return destination and returns the shelf number N013 of the boat 17.
approach the wafer cassette 21 and place the wafer W3 in the wafer cassette 21.
Return to the shelf with shelf number N004 and transfer. Similarly, the wafer W on the fence with shelf number 3 of the boat 17 is transferred back to the shelf with shelf number 5 of the wafer cassette 21. When this return transfer cycle is completed, the shelf number No. 6 column of the table in Figure 3 is accessed, and since the value in this column is "0", the return transfer operation is stopped, and then the corresponding The shelf number 7 column of the table is accessed. The value in this column is also "0", so next,
The column of shelf number N008 of the table is accessed. Since the value in this column is "1", the transfer robot 19 is designated as the shelf with the shelf number of the wafer cassette 21 as the wafer return destination, and transfers the vacuum 1st pen 19A to the shelf number N of the boat 17.
The wafer W is approached to the shelf No. 005 and transferred back to the shelf No. 8 along the route shown by the double arrow in FIG.

In this way, when one return transfer cycle is completed, the next shelf number column in the table is accessed and the value of this column is set to "
1", the shelf with this shelf number is specified as the wafer return destination, and the vacuum suction ben 19A executes the return transfer cycle. If the value in this column is "0", the wafer is returned to the shelf with this shelf number. The transfer cycle is stopped and the next shelf number column is accessed, and this is repeated until the column with the value "1" is accessed, ensuring that each wafer in the boat 17 is
The wafer cassette 21 is returned to its original shelf.

Note that the moving path of the vacuum suction ben 19A is not limited to that shown in FIG. Although the case where the wafers are sequentially transferred from the upper shelf to the lower shelf of the wafer cassette 17 has been described, in an actual apparatus, the order in which wafers are taken out from the wafer cassette 21 is from bottom to top, and the boat 17 is loaded with wafers from the upper shelf. It is desirable to transfer items sequentially from the shelf to the lower shelf.

This is because it is possible to reduce adverse effects such as falling of foreign objects when the vacuum suction ben 19A moves.

Further, since the table memory RAM (DRAM) 50A is a backup memory, even if there is a momentary power outage, the written type information will not be erased, so the transfer operation can be performed as is.

〔Effect of the invention〕

As explained above, when the wafer cassette is not full of wafers and there is a blank space, the robot finger that approaches this blank space will approach the next shelf without performing a transfer cycle, and the transfer within the boat will be carried out. Since the loading is done in the order of the shelves on the boat, even if there is a blank space in a wafer cassette, it can be transferred to the boat without creating a blank space, and therefore, there is no problem with the mutual spacing of wafers within the boat. It is possible to prevent the occurrence of uneven processing due to uniformity,
Yield can be improved compared to conventional methods. Also, when transferring wafers back from the boat to the wafer cassette,
Since the return destination is designated and the return transfer is performed based on the species information of the wafer cassette before the wafer is transferred from the wafer cassette to the boat, the wafer can be reliably returned to the original shelf of the wafer cassette.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a control device for explaining the present invention in detail, and Fig. 2 shows a vacuum suction pen of the mobile robot in the above embodiment approaching the fence of the wafer cassette and transferring the wafer to the fence of the boat. FIG. 3 is a table of the table memory used in the above embodiment, FIGS. 4 and 5 are transfer programs for the mobile robot in the above embodiment, and FIG. 6 is a diagram showing the vacuum suction route when A schematic diagram showing an example of a system of a surface treatment apparatus, FIG. 7 is a longitudinal sectional view showing a processing unit in the above system, FIG. 8 is a diagram showing a wafer cassette in the above system, and FIGS. 9 and 10 are respectively The top view and longitudinal sectional view of the boat in the above system, and Figure 11 show the path of the vacuum suction pen of a conventional mobile robot when it approaches the wafer cassette shelf and transfers the wafer to the boat column. FIG. 10-Reactor, 12--Elevator, 17--Boat, 18--Transfer device, 19--Transfer robot, 19A--Vacuum suction pen, 20--Stage, 21-- Wafer cassette, 50- sequencer, 50A-- table memory, 51- transfer robot control device.

Claims (2)

[Claims] (1) Wafer cassettes that can store a predetermined number of wafers in stages on each shelf at regular intervals, and are loaded into and taken out from a stage at a predetermined position; a boat that can be stored in stages and transferred from a fixed location into a processing unit or vice versa;
A transfer in which the wafer cassettes are approached one after another in shelf order according to a predetermined sequence, or the wafers are taken out one by one by approaching the shelves of the boat one after another in order of shelf order, and transferred from the wafer cassette to the boat or vice versa. In a surface processing apparatus equipped with a transfer robot that executes a loading cycle, in the transfer sequence from the wafer cassette to the boat, if there are no wafers on the shelf of the wafer cassette that is approached, the transfer cycle is stopped and the next step is performed. A surface processing device that approaches a shelf of a tier, and if there is a wafer on the approached shelf, continues the transfer cycle. (2) Wafer cassettes that can store a predetermined number of wafers in stages at regular intervals in each column and are loaded into and unloaded from a stage at a predetermined position; boats that can be stored in stages on shelves and transported from a fixed location into a processing unit or vice versa;
A transfer in which the wafer cassettes are approached one after another in shelf order according to a predetermined sequence, or the wafers are taken out one by one by approaching the shelves of the boat one after another in order of shelf order, and transferred from the wafer cassette to the boat or vice versa. In a surface processing system equipped with a transfer robot that executes a loading cycle, the control unit that controls the transfer sequence is equipped with a table memory that has various shelf number columns and write fields for wafer cassettes, and the control unit that controls the transfer sequence is equipped with a table memory that has various shelf number columns and write fields for wafer cassettes. In the transfer sequence, if there are no wafers on the shelf of the approached wafer cassette, write "None" in the shelf number column of the shelf in the table above, cancel the transfer cycle, and approach the next shelf. If there are wafers on the approached shelf, write "Yes" in the shelf number column of the shelf in the table above and continue the transfer cycle, and in the sequence of transferring the wafers from the boat back to the wafer cassette. If the above table is accessed and the value in the accessed shelf number column is "Yes", the shelf with this shelf number is specified as the wafer return destination, and the transfer robot starts the return transfer cycle. Execute, and if the value in this field is "None",
A surface treatment apparatus characterized in that the return transfer cycle is stopped, a next shelf number column is accessed, and this is repeated until a column with a value of "present" is accessed.