JPS61229725A - Wafer processor - Google Patents

Abstract

PURPOSE:To efficiently improve productivity and make into a smaller size by vertically moving cassettes accommodating a number of wafers interlockedly, centering the wafers carried out of the cassettes, transferring the wafers onto a wafer chuck for positioning and performing a chip test. CONSTITUTION:Wafer cassettes WK1-WK4 that accommodate a number of wafers are stacked to form two-decker stacks with openings opposed to one another and each of the two-decker stacks is vertically moved with one cassette interlocked with the other. A finger FG for placing the wafers is made capable of pantographical movement by arms AM1 and AM2 and shafts G1, G2 and G3. The wafer WF carried out of the cassette WK by the arms AM1 and AM2 and the finger FG is centered by a centering hand CH, transferred to a wafer chuck WCT on an X-Y stage ST, positioned by a sensor QS either manually under visual observation through a monitor TVD or automatically, and then a chip test operation is performed under a microscope OP.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field] The present invention relates to a wafer processing apparatus used for processing wafers for manufacturing high-density integrated circuits, ie, circuit baking, surface inspection, chip operation testing, etc.

[Prior art]

゛Conventionally, in this type of equipment, its accuracy, productivity,
There were problems with the area occupied, and particularly with the wafer cassette placement mechanism, wafer removal and storage mechanisms.

〔the purpose〕

The present invention solves the above-mentioned difficulties and has features such as ultra-precision, high productivity, and miniaturization. In particular, the arrangement of the wafer cassette, wafer ejection, and storage mechanism are improved, and it is effective in high productivity and miniaturization. The purpose is to provide a wafer processing apparatus that is

(Embodiment) FIG. 1 is an overall overview diagram of a wafer prober according to an embodiment of the present invention, and WKI to WK4 are four wafer cassettes that store a large number of wafers WF, with openings facing each other. Stack in two layers. WKDI and WKD2 are drive units for interlocking the two stages of wafer cassettes and moving them up and down, respectively;
FG is the wafer mounting finger, AMI.

AM2 is arm, Gl, G2. G3 is a shaft and finger FG
is constructed so that it can be moved telescopically. AD is a drive unit that allows the arm and finger to move vertically and rotatably. Wafer cassette) Arm AMI from WK.

Wafer WF carried out by AM2 and finger FG
is centered by a centering hand CH and transferred onto a wafer chuck WC on an XY stage ST. The transferred wafer WF is repositioned by the capacitive sensor QS. At this time, the positioning is performed manually or automatically by visual observation using a television (TV) camera TVK and a television monitor TVD.

The wafer WF, which has been accurately positioned on the wafer chuck WC by the centering hand CH, is set directly below the microscope fiOP by moving the XY stage ST, and the chip terminals on the wafer WF and the probe terminals (not shown) can be aligned by visual observation. It is done. After that, a predetermined chip test operation is performed, and after the test, the wafer WF is transferred to the finger FC.
, AMI, and AM2 return the wafer cassette WK to its original position and repeat one or more operations to perform a chip test operation. Second. FIG. 3 is a side view and a top view of the main part of FIG. 1, showing the removal of the wafer from the cassette WK.

For example, a wafer cassette WK is a diagram showing how it is stored.
4 and the wafer cassette WK3 are raised to a predetermined position by the wafer cassette driving section WKD. Finger FG
and Arm AMI.

AM2 is moved left and right by an arm extension/contraction drive unit AD to take out and store wafers WFI to WF4, etc. The arm extension/contraction drive unit AD is moved up and down by an elevating mechanism HD to select a specific wafer from wafers WFI to WF4, etc. MO is a drive unit that provides rotational motion to the arm extension/contraction drive unit AD, and performs a wafer transfer operation between the wafer cassette WK and the wafer chuck WC.LZ is a semiconductor laser source, and HM is a laser beam from the semiconductor laser source LZ. The half mirror irradiates the light LW toward the wafer cassette side, and transmits the laser light LW reflected by the total reflection mirror FM provided at the outer end of the wafer cassette to the semiconductor laser sensor PS. By detecting this reflected laser light, the semiconductor laser sensor PS can reliably know the current position of the wafer WF, and can prevent malfunctions such as collision between the fingers FG and the wafer WF. Furthermore, since a semiconductor laser source is used as a light source, the accuracy of wafer position detection is significantly improved compared to a light emitting diode or the like. Further, since a large number of wafer cassettes can be set for both taking out and storing wafers, the wafer processing speed is greatly improved. Furthermore, the sensor PS can also read wafer cassette identification code information KC3, KO2, etc.

That is, KO2, KO2, etc. are made up of codes representing logic rlJ, rQ, and the sensor PS moves vertically and/or horizontally to read the code information of KO2, etc., and the cassette number etc. can be known.

FIG. 4 is a diagram showing an example of a wafer WF used for circuit burning, inspection, etc. WCN is code information for sorting wafers, and this information is used to prepare and prepare wafer numbers, wafer cassette numbers, loft numbers, etc. Various methods such as exposure printing from a reticle original plate, laser printing, and ink are used to write the information, and a television camera TVK shown in FIG. 1 is used to read this information. CHP indicates the circuit chip area to be tested.

Figure 5 is a front view looking at the opening of the wafer cassette (WK).
FIG. 4 shows how, for example, 25 wafers WF are stored. Here, wafers WF2 and WF3 are shown with an emphasis on the case where they have been deformed into arcuate shapes due to various treatments of the wafers. Strictly speaking, it is generally considered that the wafer has lost its flatness, so when taking out the wafer, etc.
It is necessary to pay close attention to the position of G entry. Therefore, the position of each wafer may be accurately detected in advance before the finger moves in and out, and the safest entry position of the finger FG, that is, the center position between each wafer, P1 to F26, etc., may be calculated.

FIG. 6 is a flowchart showing a finger entry/exit control procedure, which is stored as a microinstruction in the read-only memory ROM of FIG. 1, and the operation will be described below according to this procedure.

In step SAl, first, the wafer position detecting means, for example, the laser sensor PS, starts to rise from a predetermined origin position, for example, the lowest position in FIG. 5, and fine detection of the wafer position is started. The first distance d1 is determined at the stage when the sensor PS detects the first wafer Fl, and the second wafer WF is similarly determined.
2 is detected, the distance d2 is determined, and in step SA2, dl and d2 are stored in the random access memory RAM shown in FIG.

Next, in step SA3, the microprocessor MPU shown in FIG. 1 calculates d 1/2 and d2/2 in order to find the center position between each wafer, and stores each value in the RAM. Since it is possible to accurately take out and store the first wafer WF1 by simply measuring the distances di and d2 between these two locations, the sensor P
S is lowered to the origin in step SA4.Finger FG is then lowered to step S to take out the wafer WFI.
Raise it to the position of dl/2 calculated in A3. This allows the finger FC to be positioned at the safest point P1 in FIG. At this point P1, move finger FG to arm A.
MI and AM2 are used to extend the wafer and insert it into the wafer cassette WK (step 5AD), then further raise the finger FC by d1/2 (step 5A7), so that the upper surface of the finger FG can come into contact with the lower surface of the wafer WFI. Therefore, the vacuum suction mechanism (not shown) is turned on and operated, and the fingers FG attract the wafer WFI (step 5A).
8) L, then roughly rise by d2/2 (step 5A
9) Then, the fingers FG are pulled out from the wafer cassette WK while holding the wafer WF2 (step SA).
10) Then, the wafer WFI is transferred to the xY stage ST by arms AM1 and AM2 (step SA l l), and processing such as one circuit baking and inspection is performed (step 5A12). When the processing is completed, the processed wafer WFI is transferred to the xY stage ST.
It is collected from the stage ST to the finger FG, is adsorbed again (step 5A13), rotates to the origin (lowest position) in FIG. 5, and stands by facing it. In order to store the wafer WFI, the finger FG is now raised to the position dl+d2/2 in FIG. Insert (step 5A15) 0 Then lower finger FG by d2/2 (step S
A16) As a result, the wafer WFL rides on the protrusions KR and KL at the original position, and then the vacuum suction mechanism is turned off, so the wafer WFI is separated from the finger FG (step 5A17), and then the finger FG is further moved d2.
/2 (step S A 18), and then only the finger FG is pulled out from the cassette wK (step 5A
19) Taking out and storing the wafer WFI is performed accurately and safely by the control of 0 or more.
When taking out and storing the sensor ps is d2. Measure d3, calculate d2/2 and d3/2, store them, and perform the same control as above. Therefore, all positions 11 of each wafer
There is no need to memorize dl-d28, and dn can be stored in at most 2 locations.
Since it is sufficient to have a memory address of dn+1, the memory saving effect is large. However, all positions of each wafer may be stored.

FIG. 7 is a flowchart showing a plurality of modes of processing the four wafer cassettes shown in FIG. 1, and the instructions thereof are stored in the ROM as in the previous example. That is, two pairs of wafer cassettes WK 1eWK3 , WK whose openings face each other
2 This is an example of control in which the MWK4 can be used to select whether each cassette is used for both wafer ejection and storage, or only for ejection and storage.0 For example, if the inspected wafer is defective. If this is found to be the case, it may be desirable to store the error wafers together in a dedicated cassette without returning them to the same original position as when they were taken out. There are also cases where it is desired to improve the processing speed of wafers, that is, to save time for exchanging wafer cassettes. Therefore, it is preferable to be able to suitably select between the above two modes, as this will improve usability.In step SBI in FIG. 7, it is first determined which mode is to be operated. To do this, check the specific flag in the RAM shown in Figure 1, and if the specific flag is, for example, rl.
If it is "J", step 5B2111 is set to the dual-use mode of ejecting and storing; if it is "0", step SB7 is ejecting,
Each of the wafers WKI and WK2 (wafer cassette when proceeding to step 5B21) is taken out in sequence, and after processing such as inspection is completed, the wafers are stored in their original locations. This operation control is performed according to the control procedure shown in FIG. 886 described above. During the processing of wafer cassettes) WKI and WK2, the wafer cassettes) WK3. W
Replace K4 with a new one containing the wafer to be processed. Wafer cassette) When all the wafers in WKI and WK2 have been processed, the process proceeds to steps 5B41 and 5B42. In step 5B41, the wafer cassette WK3. Each wafer of WK4 is taken out in order, processed, and then stored in its original location.
At the same time, the wafer cassette (WKI, WK2) is replaced with the new one.Before processing the wafer cassette WK3, the wafer cassette identification code information may be read from the mark plate KC3 by the sensor PS and stored in the RAM.If configured in this way, Unmanned supply management of wafer cassettes is facilitated, and the cleanliness of the environment is also easily maintained. Furthermore, since a special sensor for identifying wafer cassettes is omitted, the structure can be made compact, and therefore a large clean room is not required, and the cost of maintaining the clean room is also reduced.

The above procedure is repeated and when the sensor PS and MPU determine that all cassettes have been filled, the process stops. Step SB
When it is determined that the wafer is in the take-out/storage-only mode, the process proceeds to step SR7. In step SB7, the wafer is taken out from the wafer cassette WKI, processed, and then the normal wafer is returned to the wafer cassette WKI, and the error wafer is returned to the opposite wafer cassette WKI. wafer cassette WK3. (The storage method in step 5 is a standard wafer cassette.) Since the positions of the wafer supporting protrusions KR and KL of WK are stored in advance in the ROM or RAM, the position of the fingers FG is controlled by reading them out. When the wafer cassette WK1 is completed, the process moves to the wafer cassette WK2, and the error wafer is stored in the opposing wafer cassette WK4 as described above. When all the wafers in the wafer cassettes WKI and WK2 have been processed, the process proceeds to step SB9, and the wafer cassette W
All of KI #WK4 will be replaced with new cassettes. As a matter of course, the new cassettes WKI and WK2 contain unprocessed wafers, and the new cassette WK3. WK4 is left empty. When the sensor PS and MPU determine that all predetermined cassettes have been filled, the process stops.

As described above, the present invention can greatly contribute to high productivity and miniaturization.

[Brief explanation of drawings]

FIG. 1 is an overview perspective view of one embodiment of the present invention, FIG. 2 is a partially enlarged side view thereof, FIG. 3 is a partially enlarged top view thereof, FIG. 4 is a front view of the wafer, and FIG. 5 is a partially enlarged side view thereof. The front view of the opening of the wafer cassette, FIGS. 6 and 7 are control flowcharts. F G---Finger AM---Arm P 5---Sensor W K---Wafer cassette

Claims (4)

[Claims] (1) Wafer removal and storage equipped with a plurality of wafer cassettes that each store a plurality of wafers, a vertical movement mechanism that moves each of the wafer cassettes up and down, and a movable mechanism that can face each opening of the wafer cassette. A wafer processing apparatus comprising: means. (2) The wafer removal and storage means includes a semiconductor laser source;
The wafer processing apparatus according to claim 1, further comprising a wafer position detection mechanism comprising a semiconductor laser sensor. (3) The wafer processing apparatus according to claim (1), wherein the movable mechanism includes rotation or vertical movement means. (4) The wafer cassette includes at least a pair of wafer cassettes with openings facing each other, and the wafer removal and storage means is arranged approximately at the center of the pair of wafer cassettes. Part (1)
The wafer processing apparatus described in Section 1.