JPS6236839A - Wafer processor - Google Patents

Abstract

PURPOSE:To provide a safety of a laser for detecting the position of a wafer by providing a laser generation source composed to move linearly and rotatably and means for allowing the source to emit a laser light only when the source is disposed at the specific position. CONSTITUTION:A half mirror HM emits a laser light LW from a semiconductor laser source LZ toward a wafer cassette side, transmits a laser light LW reflected on a fully-reflecting mirror FM provided at the outer end of the cassette to a semiconductor laser sensor PS. Accordingly, the present position of the wafer WF can be effectively known to prevent an erroneous operation. A semiconductor laser source is used as a light source to remarkably improve the wafer position detecting accuracy. Further, the laser light can be interrupted in response to the rotation of a driver AD to safely operate. In other words, a laser light interrupting plate LS is integrated with a plate EB, a hole LH is formed at the plate LS, the laser light passes the hole LH at the position as shown, and is interrupted at the other position.

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, and the like.

[Prior Art] Conventionally, this type of apparatus has had drawbacks in its accuracy, productivity, occupied area, etc., and in particular, there have been problems with the safety mechanism for the laser used to detect the wafer position.

[Objective] The present invention solves the above-mentioned difficulties, and provides an evaporation processing apparatus that has features such as ultra-precision, high productivity, and miniaturization, and in particular has safety measures against lasers for wafer position detection. The purpose is to

[Embodiment] FIG. 1 shows an overall schematic diagram of a wafer blobber according to an embodiment of the present invention. In the figure, WKI to WK4 are four wafer cassettes that store a large number of wafers WF, and are stacked in two stages with their respective openings facing each other. WKDl, WKD2
1 is a drive unit for vertically moving each of the two stages of wafer cassettes in conjunction with each other via a support plate KS, FG is a finger for mounting wafers, and AMl and AM2 are arms. Gl,
G2.

G3 is the axis, arm AMI, AM2 and finger FG
is constructed so that it can be moved telescopically. AD is a drive unit for telescopically moving the arm and finger. Further, this drive unit AD is configured to be able to move up and down and rotate freely by mounting the arm and finger. Wafer WF carried out from wafer cassette WK by arms AMI, AM2 and fingers FG is centered by centering hand CH and placed on XY stage 5T-F.
wafer chuck WC. Transferred Eva W
F is repositioned by a capacitive sensor QS.

At this time, the positioning is performed manually or automatically by visual observation using the television (TV) camera 1VK and the television monitor TVD.

Wafer chuck WC by centering hand Cl-1
The wafer WF that is accurately positioned is placed on the XY stage ST.
By moving it, it is set directly below the microscope OP, and the eye? [The chip terminals on the wafer WF and the probe terminals (not shown) are aligned by inspection or automatically. After that, a predetermined chip test operation is performed, and after the test, the wafer WF
is finger FG1 arm AM1. The wafer cassette WK is returned to its original position by AM2. By repeating the above operations, each wafer WF in the wafer cassette hWK
A chip test operation is performed sequentially for each.

Second. FIG. 3 is a side view and a top view of the main part of FIG. 1, showing how the wafer WF is taken out and stored from the wafer cassette WK. However, finger FG and arm AM
1. AM2 has been rotated 90° clockwise with respect to FIG. In the same figure, for example, the Uniba Hits WK4 is a wafer cassette drive unit WK together with a wafer cassette WK3.
The wafer is pushed upward to a predetermined wafer delivery and collection position by D2.

The fingers FG and the arms AM1 and AM2 are expanded and contracted by a pulse motor SM built in the arm expansion/contraction drive unit AD to take out or store the wafers WF1 to WF4, etc. The arm telescopic drive unit AD is moved up and down together with the base KD by the movable plate EB of the elevating mechanism HD, and the wafers WF1 to WF4 are moved up and down together with the base KD.
A specific wafer is selected from among the following. MO is a rotation drive unit for rotating the arm extension/contraction drive unit AD along with the base KD, and performs a wafer transfer operation between the wafer cassette WK and the wafer chuck Wc.

LZ is a semiconductor laser source, l-IM is a semiconductor laser source L7
This is a half mirror that irradiates the laser beam LW from the wafer cassette toward the wafer cassette side.The laser beam reflected by the total reflection mirror FM (FMR or FML) provided at the outer end of the wafer cassette transmits the laser beam W to the semiconductor laser sensor PS. introduce. A semiconductor laser sensor PS inside the protective case SB detects this reflected laser light.

Since this apparatus is configured as described above, the wafer W
The location of F can be reliably known, and malfunctions such as collision between finger FG and wafer WF can be prevented.

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. Furthermore, since the laser beam can be blocked according to the rotation of the drive unit AD, safe operation can be achieved. That is, the laser beam blocking plate LS is integrated with the plate FB, and the plate LS is provided with a hole Ll-1, and the laser beam passes through the hole LH at the position shown in FIG. It is blocked because there is no.

This is preferable because the laser beam is emitted only at necessary positions and not at unnecessary positions, ensuring safety during maintenance and inspection.

Furthermore, since the semiconductor laser source LZ is arranged so that the light emission direction is directed upward as shown in FIG. Pulse motor SM for expansion and contraction
This is preferable as it allows coexistence with Also half mirror)
The IM and semiconductor laser sensor PS are arranged at positions opposite to the direction in which the fingers FG extend, as shown in FIG. 2.3. This is preferable because the optical path of the sensor PS is not blocked by the arm and the extension and contraction of the arm is not obstructed. A vacuum tube TU for wafer suction is placed along this telescopic arm by a method such as penetrating it, fitting it into a groove, or adhering it. As a result, the arms and tubes, which have a large range of movement, move around in conjunction with each other, so the tubes and arms do not become entangled, and the overall space can be made smaller.

In FIG. 2, KS4 U and KS4 L are wafer uppermost (lower) position signal generating means, each consisting of a protrusion, for example, and L-E and PH in the lowering mechanism Hrt detect the position of the movable plate EB, and detect the position of the wafer. This is a light emitting/receiving element that determines the delivery or collection position.

The finger [G has a simple structure of two upper and lower plates FGLJ and FGL glued together as shown in FIGS. 4A, B, and G.

-Plate FGU is provided with through holes U1 to UIO, and lower plate FGL is provided with grooves Ll and through holes ]-2 to L7.

And groove L1 and hole ui, Li2.

A vacuum suction chamber is formed with U3. That is, the groove L1 is the hole t.
J10. The tube TU is connected and exhausted via the tube boulder T+-1. When a wafer is placed on the upper part of the suction chamber formed as shown in FIG. 4B, the wafer is suctioned and becomes a closed chamber, where wafer suction is performed. Also, hole ()8
．． U9. For L6.17, etc., there are bins SR, , as shown in Figure 4C.
SL is fitted. The bins SR and SL- are positioning members for positioning the end face of the wafer WF as shown in FIG. Select one and fit the bottle SL. Similarly, for bottle SR, holes U5 and Li
2.

Select U9 and fit it to φ. This makes it possible to optimally determine the bin position for wafers of different diameters, which is preferable.

As shown in FIG. 2, the upper wafer cassettes WKI, WK3 are constructed such that, for example, support plates KS3, KS3B are bendable by an external force by a hinge mechanism CT. This makes it easy to replace the lower cassettes WK2 and WK4, which is preferable. Note that it is not necessary to provide two mirrors FM at the rear of the cassette, one above the other, and only one mirror with a length corresponding to a single cassette is placed at the position corresponding to the wafer removal and storage position @ (the upper position of the cassette in Figure 1). Just be prepared.

The aforementioned sensor PS is the wafer cassette identification code information KC.
3. KO2 etc. can also be read.

That is, KO2, KO2, etc. consists of a code representing logic 11'' and rOJ, and the sensor SP moves vertically and/or horizontally to read the code information such as KO2, etc., thereby knowing the cassette identification number. .

FIG. 5 shows an example of a wafer WF used for circuit burning, inspection, etc. In the same figure, WCN is code information that identifies the wafer, including the wafer number, wafer cassette number, and lot number.
A number etc. will be prepared. To write this information, various methods such as exposure printing from a reticle original plate, laser printing, ink, etc. are used, and to read this information, a television camera TVK shown in FIG. 1 is used. CHP indicates the circuit chip area to be tested.

Figure 6 is a front view of the opening of the wafer cassette WK.
A state in which, for example, 25 wafers WF of FIG. 5 are stored is shown. Here, wafers WF2 and WF3 are shown with 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 it is necessary to pay close attention to the insertion position of the fingers FG when taking out the wafer. Therefore, it is sufficient to accurately detect the position of each wafer in advance before moving the finger in and out, and to lock out the safest entry position of the finger FG, that is, the center position P1 to I''6 between the wafers.

FIG. 7A is a control block diagram for that purpose, and FIG. 8 is a flowchart 1 showing the control procedure, which is stored as a microinstruction in the read-only memory ROM of FIG. Explain the operation. In step SAI, the wafer position detection means, for example, the laser sensor PS starts to descend and starts detecting the wafer position, for example, when it detects the uppermost position signal generation means KS4U shown in FIG. The first distance d26 is determined at the stage when the sensor PStfi detects the first wafer WF25, and similarly 2
At the stage when the first wafer WF24 is detected, the distance @ d 25
is determined, and detection is performed in the same manner up to the lowest dl.

At this time, the sensor PS may be raised at a constant speed, that is, at a constant speed that is lower than the response speed of the sensor PS, but this inevitably reduces the overall detection speed.

Therefore, as shown by waveform A in FIGS. 6 and 7B, the sensor PS is lowered at high speed at the position where the wafer is not present.
It is sufficient to move at a low speed at the position where the wafer is present. Therefore, the positions ID1 to D26 of each wafer in a standard wafer cassette may be stored in advance in a part of the ROM shown in FIG. 7A, and the operation may be controlled according to the stored contents.

That is, first, the microprocessor MPU takes in the standard position information D26 from the address ADI of the ROM, and based on this information, determines the pulse train 1) M shown in FIG. 7B, for example. Pulse width T1 to T of each pulse of this drive pulse train DM
10 is stored in a table format in an unillustrated part of the ROM, and first, binary coded 1-to-1 information corresponding to T1 is stored in M.
It is stored in the down counter OK under the control of P LJ. At the same time, the flip-flop ``['' is set, and the motor drive circuit MD operates.A quaternary counter is built in the motor drive circuit M['), and the first output opens the AND gate A1, and the first The pulse motor PM starts to be activated by the drive pulse (T1).

The down counter [)K starts subtraction in response to the oscillation pulse of the oscillator O8C, and when the value reaches a specific value, e.g. Reset. This ends the drive pulse T1. Similarly, AND gate A2,
A3 and A4 are sequentially passed, and driving with the pulse width T1 is completed.

Next, time information corresponding to the pulse width T2 is stored in the down counter DK, and the same operation as above is performed. As shown in FIG. 7B, the pulse width gradually becomes shorter as <T3 and T4, and the falling speed of the sensor PS gradually increases, and when the pulse width T4 is repeatedly driven, it falls at a constant high speed. , when approaching the vicinity of the first wafer WF 25 shown in FIG. 6, the pulse width shown in FIG. 7B becomes T5, T6.
The sensor PS continues to descend while being decelerated, and the sensor PS is located near the location of the wafer WF 25.
When the sensor PS reaches the laser beam, the sensor PS descends at a constant low speed sufficient to detect the laser reflected light. At this time, the pulse width T7
The pulse motor PM is driven by the drive pulse. When the position detection of the wafer WFI is completed, the pulse widths T8 and T9
, 71o, the descending speed of the sensor PS gradually increases, and it continues to descend at a constant high speed as before, and when it descends to a predetermined level, it specifies the second address AD2 of the ROM in FIG. 7A, Extract position information Dm. This positional information Qm is expressed in terms of wafer spacing, and is standard positional information 025~
D2 is common, and only one address AD2 is sufficient as the data area for the position information Dm. Thereafter, the same operation as described above is repeated until D2 according to the position information Dm, and finally the ROM address AD3 is specified, and the bottom position information D
1, the sensor PS detects the lowest position signal generating means KS4L and stops the lowering.

Since the actual position of each wafer is detected in this way, the next full-scale wafer removal and storage becomes extremely accurate.

Also, if it is detected that no wafer actually exists during this wafer position detection, that fact is written in the RAM.If this wafer presence/absence information (1,0) is written in the RAM together with the wafer position information, the wafer can be detected. This is convenient because it allows you to quickly skip to a position that does not exist. Standard position information for other wafer cassettes of different sizes is also stored in the ROM.
It is more preferable to store them in addresses AD4 to AD6 and use them selectively.

Next, in step SA2, the detected center positions d1/2 to d26/2 between each wafer are determined by the microprocessor M.
PtJ starts and stores each value in the RAM of FIG. 7A as shown. Next, in order to take out the wafer WF1, the finger FG is raised from the current position (lowest point) to the position d1/2 calculated in step SA2 (step SA
3). As a result, the finger F is placed at the safest point P1 in Figure 6.
G can be located. To stop at this position, use the target value storage register OR and up counter UK shown in Figure 7A.
1. A matching circuit CO for both is used. Waveform B in FIG. 6 shows the rising speed curve of the finger FG at this time.

At this point P1, extend the arms AMI and AM2 and insert the fingers FG into the wafer cassette WK (step SA
4), and further drives the lifting mechanism 1''D to raise the finger FG by d1/2 (step SA5).

The upper surface of the finger FG can now come into contact with the lower surface of the wafer WF1, so the vacuum suction mechanism described above is turned on and operated, and the finger FG attracts the wafer WFI (go to step S)1-. Then finger FG, then d
Lift up by 2/2 (step SA7) L, then pull out from the wafer cassette WK while holding the wafer WFI (step 5A8). Next, the arm telescopic drive unit AD is rotated by 90 degrees by the drive unit MO to make the finger FG face the XY stage ST, and the arms AMl and AM2 are extended to move the wafer WF1 from the finger FG to the centering hand C.
Transfer to H (step SA9). The wafer WF1 is moved roughly from the centering hand Cl-1 to the XY stage ST.
(Step S A 10), and processes such as circuit burning and inspection (Step 5A11) are performed.

When the processing is completed, the processed wafer WF1 is transferred from the XY stage S1- to the finger F via the centering hand CH.
G and adsorbed again (step 5A12.13). Next, the arms AM1 and AM2 are contracted and rotated,
To store wafer WF1, move finger FG to the current position (
R upper point) to the position of dI +62 /2 in FIG. 6, that is, the safety point P2 (step 5A14). At this position P2, extend the arms AMI and AM2 and insert the fingers FG into the wafer cassette WK (step 5A15).
do.

Next, lower the finger FG by d2/2 (step S
A 16) Let it happen. As a result, the wafer WFI rides on the protrusions KR and KL at the original position, and then the vacuum suction mechanism is turned off, so the wafer WF1 is separated from the finger FG (step S A 17), and then the finger FG is further moved by d2/2. It is lowered (step S A 18) and only the finger FG is pulled out from the cassette WK (step S A
19) To be killed. The above control allows the wafer WFI to be taken out and stored accurately and safely. Then wafer WF
2 takeout and storage control is now d2 /2. d3
The same procedure as above is performed based on the value of /2, and in the same way, n-
Do this until you reach 26.

FIG. 9A schematically shows the above situation. In the figure, X indicates the standby position of the finger FG, which detects the position of the wafer as it descends from this point to point Y (end point), and then picks up the wafer WFI closest to that position. Therefore, the insertion of the finger FG into the cassette WK is started at point A, the removal is completed at point 8, the transfer to centering hand Cl-1 is performed at point 0, and the insertion from centering hand Cl-1 is performed at point D. Retrieval is performed, and finger FG is used for wafer storage at point E.
The insertion of the wafer into the cassette WK is started, the storage is completed at one point, and the removal and storage of the second wafer WF starts from that position.

In the figure, all three wafers, WF1 to WF3, are used for ease of understanding.
Shown as a sheet. Further, the processes corresponding to each point A to F are indicated by the same reference numerals in the flowchart of FIG. Further, the standby position @X of the finger FG is set at approximately the same height as the centering hand CH, and near the uppermost wafer WF3. Therefore, the total vertical movement distance is shorter than in the example shown in FIG. 9B, which is preferable. This also applies to FIG. 9r1.

FIG. 9B shows an example in which the position of the centering hand CH, that is, the wafer delivery or collection position, and the position of the lowest wafer WFI are set to be almost on the same line, and the standby position of the finger is also set on the same line, In this case, as shown in the figure, the total distance of vertical movement of the finger becomes long. Move the finger standby position X in Figure 9B to the top wafer WF3.
As shown in Figure 9F, even when the finger is set at a position near , that is, at position Y in Figure 9B, the overall vertical movement of the finger is almost the same as in Figure 9B and longer than in Figures 9A and 9P. It is obvious. However, it is preferable that each of the wafers be taken out and stored starting from the wafer closest to the position where all scanning for wafer position detection has been completed. Furthermore, it is preferable to process the wafers from the bottom to the top so that the upper wafers are less contaminated. The example in FIG. 9C shows a situation in which the wafer transfer or collection position If (position of the centering hand CH) is set at approximately the center position of the wafer cassette, that is, near the middle wafer WF2, and in this case, the total vertical movement of the finger FG is The distance is the shortest and the most preferable. This is evident since all wafers must be transported to a predetermined fixed point, ie, a wafer transfer or collection location. This advantage can be similarly expected in the case of FIG. 9F. Saving even a small amount of wasted time in this manner contributes to increasing the overall speed of wafer processing in this type of apparatus, and is therefore extremely desirable.

In general, the wafer cassette does not always contain all the wafers, and there are cases where defective wafers are removed beforehand and transferred to this prober. If the operations related to wafer removal and storage of the fingers FG are skipped in the position where the wafer is not loaded, the overall processing speed can be improved. This will be explained below. In FIG. 6, it is assumed that the wafer WF2 is now missing. As explained above, when it is detected that each wafer exists at a predetermined position, R in FIG.
Logic "1" is written as shown in AM, and half the value of the position information of each wafer is written in d26/2. It is stored in RAM like d25/2. When the sensor PS detects that the missing wafer WF2 does not exist, it writes logic fllrOJ to the address Ad2 of the RAM, and further writes Qm as position information to the right side. As mentioned above, Om is the standard position information of the wafer. If processed in this way, wafer WF2
It is possible to avoid a measurement error of the sensor PS due to the absence of the wafer WFI, that is, the risk of mistakenly identifying the wafer WFI as the wafer WF2 when it is detected.

Also, wafer WF2 that does not exist during wafer unloading processing
It is possible to increase the speed by omitting the wasteful operation of taking out the material. That is, in the above-mentioned wafer unloading mode, the wafer W
After taking out or storing FI, RAM address Ad2
When detecting wafer no information “0”, dl /2+Dm
By performing the calculation +63/2, the vicinity of the 23 points in FIG. 6 can be obtained. Therefore, it is preferable to skip the 22nd point and quickly increase the finger FG from the 11th point to the 23rd point.

In the example shown above, the reference positions X, Y, Z are the starting point signal generating means KS4 U, KS4 L, EB (or LE
, PH), etc. may be selectively made to correspond. For example, in the example of FIG. 9A, X=KS4U.

Y=KS4L, and in the example of FIG. 9F, X=LE (or PH, EB) and Y=KS4L.

Furthermore, it is clear that the orientation of the wafer cassette is not limited to vertical, but may be set diagonally or horizontally (FIGS. 9C and 9F). Also, the wafer is 4 inches.

When the wafer cassettes have different diameters of 8 inches, the heights of the wafer cassettes also differ (the distance between each wafer is different), so
．． An apparatus of a type in which the lower side (common end) X or Y can be shared, as in the example shown in FIG. 9F, is preferable because it can handle various wafer sizes.

[Effects] As described above, the present invention can greatly contribute to laser safety measures.

[Brief explanation of the drawing]

Fig. 1 is an overview perspective view of an embodiment of the present invention, Fig. 2 is a partially enlarged side view thereof, Fig. 3 is a partially enlarged top view thereof, and Fig. 4A
4B and 4C are configuration examples of fingers, FIG. 5 is a front view of a wafer, FIG. 6 is a front view of an opening of a wafer cassette, FIG. 7 is a control block diagram of the present invention, and FIG. 78 is a control waveform diagram, FIG. 8 is a control flowchart diagram,
9A to 9F are explanatory diagrams of the operation of the fingers. FG...Finger AM...Arm PS...Sensor WK...Wafer cassette LZ...Semiconductor laser source W [...Wafer AD...Driver LS...Laser light blocking plate L H ... Hole

Claims (1)

[Claims] 1. A laser source configured to allow linear and rotational movement, and means for allowing laser emission only when the laser source is at a specific position. Wafer processing equipment. 2. A claim in which the means for allowing laser emission comprises an opaque plate material having one or more openings through which the laser beam from the laser source passes only when the laser source is at a specific position. The wafer processing apparatus according to item 1. 3. Wafer transport means for taking out a wafer from a wafer cassette and transporting it to a predetermined wafer delivery position by rotating and linear motion, or transporting the wafer collected at the delivery position to the wafer cassette and storing the wafer; A wafer processing apparatus comprising a laser source that emits a laser toward a wafer storage position of a cassette, and wafer detection means that detects the storage position or the presence or absence of a wafer at the storage position, A wafer processing apparatus characterized in that an opaque plate having one or more openings is disposed, one of the opaque plate or the laser source is fixed, and the other is linked to the movement of the transport device.