JPS6236837A - Wafer processor - Google Patents

Abstract

PURPOSE:To improve the operability of removing and containing a wafer cassette by providing supporting members for supporting the wafer cassettes respectively and a bending mechanism equipped to a part of the supporting members for altering the attitude of the cassette. CONSTITUTION:A wafer cassette WK4 is, for example, raised together with a wafer cassette WK3 by a wafer cassette driver WKD2 to the prescribed wafer delivering and recovering position. A finger FG and arms AM1, AM2 are telescoped by a pulse motor SM contained in an arm telescoping driver AD to remove or contain wafers WF1-WF4. The driver AD elevationally moves together with a base KD by a movable plate EB of an elevator mechanism HD to select a specific wafer of the wafers WF1-WF4. An MO is a rotary driver for rotating the driver AD at every base KD to convey the wafer between the cassette WK and a wafer chuck WC.

Description

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

[Prior Art] Conventionally, this type of apparatus has drawbacks in its accuracy, productivity, and area occupied, and in particular, there have been operational problems when taking out and storing wafer cassettes.

[Objective] The present invention solves the above-mentioned difficulties, and provides a wafer processing apparatus that has features such as ultra-precision, high productivity, and miniaturization, and has improved operability especially when taking out and storing wafer cassettes. The purpose is to

[Embodiment] FIG. 1 shows an overall schematic diagram of a wafer prober 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. WKDI, WKD
Reference numeral 2 designates 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 a finger for mounting wafers, and AMI and AM2 arms. G1
, 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 AI) is configured to be capable of vertical movement and rotation by mounting the arm and finger.

The wafer WF carried out from the wafer cassette WK by arms AMI, AM2 and fingers FG is centered by a centering hand CH and transferred to a sea urchin hatch Vtsuk 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 OP by moving the XY stage ST, and the chip terminals on the wafer WF and the probe terminals (not shown) are checked by visual observation or automatically. Alignment is performed. A predetermined chip test operation is performed on the bond, and after the test, the wafer W is returned to its original position in the wafer node WK by fingers FG1 and arm AM1.AM2. A chip test operation is sequentially performed for each WF in the backup set WK.

Second. FIG. 3 is a side view and an L side view of the main part of FIG. 1, showing how the wafer W is taken out and stored from the wafer cassette WK. However, finger FG and arm AM
I and AM2 have been rotated 90'' clockwise with respect to FIG. 1. In the same figure, for example, wafer cassette WK4
is the wafer cassette drive unit W together with the wafer cassette WK3.
The wafer is raised to a predetermined wafer delivery and collection position by KD2.

The fingers FG and the arms AMI 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 wafers WF1 to WF4, etc. The arm extension/contraction drive unit AD is moved up and down together with the base Kr) by the movable plate EB of the lifting mechanism HD, and the wafers WF1 to WF are
A specific wafer is selected from among the four. MO is a rotary drive unit for rotating the arm extension/contraction drive unit AD along with the base KO, and performs a wafer transfer operation between the binding support set WK and the wafer chuck WC.

LZ is a semiconductor laser source, HM is a half mirror that irradiates laser light [W from the semiconductor laser source LZ toward the wafer cassette side, and is reflected by a total reflection mirror FM (FMR or FML) installed at the outer edge of the wafer cassette. The generated laser light mW is transmitted and transmitted to the semiconductor laser sensor PS.

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 current position of finger F can be known reliably, and malfunctions such as collision between finger FG and finger 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 EB, and the plate LS is provided with a hole LH, and the laser beam passes through the hole LH at the position shown in FIG. 2, and there is no hole at the position shown in FIG. Be cut off.

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 HM
, the semiconductor laser sensor PS is arranged at a position 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 passes through this telescopic arm.
This can be done by groove fitting, gluing, or other methods. As a result, the arm, which has a large range of movement, and the tube move around in conjunction with each other, so the tube and arm do not become entangled, and the overall space can be made smaller.

In Fig. 2, KS4 U and KS41- are the uppermost (lower) position signal generating means, for example, consisting of protrusions, and IE and PH in the lowering mechanism H1 detect the position of the movable plate [B]. , a light emitting/receiving element that determines the wafer delivery or collection position.

The fingers FG are arranged in two directions, upper and lower, as shown in Figure 4 A, B, and C4.
It consists of a simple structure of two plates FGLJ and FGI- pasted together. The upper plate FG LJ is provided with through holes U1 to tJ10, and the lower plate FGI- is provided with through holes L2 to 11.
7 is set. And groove L1 and hole ui, U2
.

A vacuum suction chamber is formed with U3. That is, the groove ]-1 is the hole (Jlo, which connects the tube T through the tube holder TH.
U is connected and exhausted. A wafer is placed in the upper part of the suction chamber formed as shown in FIG. 4B, and the wafer is sucked into the closed chamber, where suction of the wafer is carried out. Also, hole LJ8
, U9, L6.17, etc., as shown in Fig. 4C, the bin SR,
St- is fitted. As shown in Fig. 3, the bins SR and SL are positioning members for positioning the end face of the wafer WF, and any one of the holes tJ4, U6, and U8 is used for wafers with different diameters such as 4 inches, 6 inches, and 8 inches. Select and fit the bottle S l-. Similarly, the bottle SR has hole IJ5.
, LJ7.

Select U9 and fit it. This is preferable because the bin position can be determined optimally for the wafer depending on the diameter.

As shown in FIG. 2, the upper wafer cassettes WKI and WK3 are constructed so that, for example, support plates KS3 and KS3B can be bent outward by a hinge mechanism CT. This will cause the lower h
Cera1-WK2. This is preferable because the WK4 replacement operation becomes easy. 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 provided at the position corresponding to the wafer removal and storage position (the upper position of the cassette in Figure 1). That's fine.

The aforementioned sensor PS is the wafer cassette 1 to identification code information K.
C3, KO2, etc. can also be read.

That is, KO2, KO2, etc. consist of codes representing logic "il, ro, I," and the sensor SP moves vertically and/or horizontally to read the code information of KO2, etc., thereby knowing the cassette identification number. can.

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

Figure 6 is a front view looking at the opening of Hatsucho Bakaset 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 when taking out a wafer, etc., it is necessary to pay close attention to the insertion position of the finger FG. Therefore, before moving the finger in and out, accurately detect the position of each wafer, and calculate the center position P1 to P26 of the finger FG (1') @ safe entry position mark, etc. between each wafer. [Noba good.

FIG. 7A is a control block diagram for this purpose, and FIG. 8 is a flowchart showing the control procedure, which is stored as microinstructions in the read-only memory ROM shown in FIG. 1.7. The operation will be explained below according to this procedure. do. In step SA1, 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 11d26 is determined when the sensor PS detects the first wafer WF 25, and the distance ijl U2 is determined when the sensor PS detects the second wafer WF 24.
5 is determined, and the detection is performed in the same manner up to the lowest dl.

At this time, the sensor PS may be operated at one valve at a constant speed, that is, 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 Jj PS may be lowered at a high speed at a position where a wafer is not present, and moved at a low speed at a position where a wafer is present. Therefore, if the digits 111 to D26 of each wafer in a standard Univac hit are stored in advance in a part of the ROM shown in FIG. That is, first, the microprocessor MPU takes in the standard position information 1126 from address A1)1 in the ROM, and based on this information, determines the pulse train OM shown in FIG. 7B, for example. The pulse widths 1 to TIO of each pulse of this drive pulse train DM are stored in a table format in an unillustrated part of the ROM, and first, the binarized time information corresponding to T1 is stored in a down counter under the control of the MPU. Stored in K. At the same time, flip-flop FF is set and motor drive circuit MD operates. A quaternary counter is built into the motor drive circuit Ml).
The first output opens the AND gate A1, and the first drive pulse (T1) starts the pulse motor PM.

The down counter DK starts subtraction in response to the oscillation pulse of the oscillator O8C, and when the value reaches a specific value, for example O, the specific value decoder, for example O de]-da DC, detects this and resets the flip-flop FF. . This ends the drive pulse T1. Similarly, AND gates A2 and A
3 and A4 in sequence, and the 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 below, <T3. The pulse width gradually becomes shorter from T4, and the descending speed of the sensor PS gradually increases until the pulse width T4.
At the repeat drive period 4, the lowering speed is lowered at a constant high speed. Furthermore, when approaching the vicinity of the first wafer WF25 shown in FIG. 6, the pulse width shown in FIG. When the sensor PS reaches the vicinity of the existing position, the sensor PS descends at a constant low speed sufficient to detect the laser reflected light. At this time, the pulse motor PM is driven by a drive pulse having a pulse width TI. When the position detection of wafer WF1 is completed, the pulse widths T8, T9', T
The sensor PS gradually becomes shorter like IO, and the descending speed of the sensor PS gradually increases.As before, it continues to descend at a constant high speed, and when it descends by a predetermined amount, the second address AD2 of the ROM in FIG.
is specified, and the position information Dm is extracted. This location information [)
m is the standard position information I) 25~O when expressed as the wafer spacing
2 is common, and address AD2 is sufficient as the data area for position information [)m. Thereafter, the same operation as described above is repeated until D2 according to the position information I[IDm, and finally, the address A113 of the ROM is designated, and the same operation as described above is performed according to the position information D1 on the bottom side, and the sensor PS
detects the lowest position signal generating means KS4L and stops the descent. 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 is actually present during this wafer position inspection, this fact is written in the RAM, and this wafer presence information (1, 0) is written in the RAM along with the wafer position information. This is convenient because it can quickly skip positions where no wafer exists. It is further preferable to store standard position information of other wafer cassettes of different sizes at addresses AD4 to AD6 of the ROM and to selectively use them.

Next, in step SA2, the detected center positions d1/2 to 62B/2 between each of the detected points are processed by the microprocessor MP.
U outputs and each value is stored in the RAM of FIG. 7A as shown. Next, in order to take out the wafer WFI, the finger FG is raised from the current position (lowest point) to the position d1/2 calculated in step SA2 (step SA3).
). This allows the finger FG to be positioned at the safest point P1 in FIG. To stop at this position, the coincidence circuit CO of both the target value storage register OR and the up counter UK1 shown in FIG. 7A is used. Waveform B in FIG. 6 shows the 1 stomach velocity curve of finger FG at this time.

At this point P1, extend arms AM1 and AM2 and insert finger FG into wafer cassette WK (step SA
4), and then drive the lowering mechanism HD to lower the finger F.
G is increased by d1/2 (step SA5). This allows the upper surface of the finger FG to come into contact with the lower surface of the wafer WF1, so the vacuum suction mechanism described above is turned on and operates, and the finger FG attracts the T-wafer WFI (step 5A6). Then finger FG, then d2/
2 (step SA7) L, then wafer W
Pull out the wafer from the cassette WK with the FI still adsorbed (step 5A8). Continuing - Rotate the C-arm telescopic drive unit 8 by 90° using the drive unit MO to make the finger FG directly face the XY stage ST, extend the arms AMl and AM2, and move WF1 from the finger FG to the centering hand C.
Transfer to H (step SA9). (3) WF1 is further transferred from the centering hand CH to the XY stage ST (step S A10), and undergoes processing such as circuit burning and inspection (step S5A11).

When the processing is completed, the processed wafer WF1 is transferred from the XY stage ST to the finger FG via the centering hand CH.
is collected and adsorbed again (step SΔ12.13). Next, the arms AM1 and AM2 are contracted and rotated, and the finger FG is lowered from the current position (the highest point) to the position of dl +62 /2 in FIG. 6, that is, the safety point P2, in order to store the wafer WF1 (step A 14) Let it happen. At this point, extend arms AM1 and AM2 at MP2 and insert finger 1G into 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 WFI moves from the finger FG to the IIIBJ.
(Step S A 17), and then the finger FG is roughly lowered by d2/2 (Step S A 18), and only the finger FG is pulled out from the cassette WK (Step S A 18).
A 19) It will be destroyed. With the above control, the WF1 can be taken out and stored accurately and safely. Next, the control for taking out and storing the Eva WF2 is controlled by d2/2.
The same procedure as above is performed based on the value of d3/2, and the same procedure is repeated until n-26 is reached.

FIG. 9Δ schematically represents the above situation. In the figure, X indicates the timing position of the finger FG, and after descending from this point to point Y (end point), the position of Insertion of the finger FG into the cassette WK begins at point A for ejection, the ejection is completed at point 8, transfer to centering hand C) (at point 0, and transfer from centering hand CH to point D). Retrieval is performed, and at point [the insertion of the finger FG into the cassette WK for wafer storage starts, the storage ends at point F, and the removal and storage of the second wafer WF starts from that position. It is shown that.

In the figure, for the sake of clarity, all 3 of WF1 to WF3 are shown.
Shown as a sheet. Further, the processes corresponding to each point A to F are indicated by the same reference numerals on the flowchart V in FIG. Further, the standby position X of the finger FG is set at approximately the same height as the centering hand C1-1 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. 9D.

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 workpiece WF1 are set almost on the same line, and the standby position of the fingers 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 9E, 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 9D. 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 that the wafer delivery or collection position (the position of the centering hand CH) is set at approximately the center position of the wafer cassette, that is, near the middle wafer WF2. The distance is the least and is the most preferable. This is evident since all wafers must be transported to a predetermined fixed point, ie, a wafer transfer or retrieval location. This advantage can be similarly expected in the case of FIG. 9F. It is extremely desirable to save as much wasted time as possible in this type of apparatus because it can contribute to improving the overall speed for processing wafers.

Roughly speaking, not all wafers are always stored in the wafer cassette, and there are cases in which defective wafers are removed from the front culm before being transferred to the main stream, and in this case, If the operations related to wafer removal and storage of the fingers FG are skipped at a position where no wafer exists, 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 moved to RAM like d25/2. When the sensor PS detects that the missing wafer WF2 does not exist, it writes a logic "0" into the address Ad2 of the RAM, and further writes Dm as position information to the right neighbor. [)m is the standard (O position information) of tsu■ha as mentioned above. In this way, if 51!lII+'1j then JhaW[2 is absent,
It is possible to avoid the measurement error, that is, the risk of mistakenly identifying WF1 as WF2 when WF1 is detected.

Furthermore, during the wafer unloading process, the unnecessary operation of taking out the 7f L and 7f WF2 can be omitted, thereby reducing the number of connections. That is, in the above-mentioned unloading mode, after the wafer WF1 is unloaded, the wafer WF1 is unloaded, and when the blank information [01 of the RAM address Ad2 is detected, dl /
2+Dm+d3/2(f>If you perform the calculation, 1 in Figure 6 is obtained.
It is possible to find the vicinity of three points. Therefore, it is preferable to skip the P2 point and quickly increase the finger FG from the 11th point to the 13th point.

- In the example of diagram F, the reference positions @x, Y, 7 may be selectively made to correspond to the positions of the start point signal generating means KS4 U, KS4 L, ``B (or LF, PI-1), etc. in Figure 2. For example, in the example of FIG. 9A, X=KS4U.

=19-Y-KS41-, and in the example of Figure 9F, X = l-E
(or PI-1, FB), Y-KS4 L may be used.

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.

Because the wafer cassettes with different diameters of 8 inches also turn yellow (the distance between each T is different), No. 91-3,
X or Y on the lower side (common end) as shown in Figures 9D and 9F
A type of device that can be used in common is preferable because it can handle various sizes of disks.

[Effects] As described in 1 below, the present invention can greatly contribute to improving the operability.

[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 the wafer, FIG. 6 is a front view of the opening of the wafer cassette, and FIG. 7 is a control block diagram of the present invention, and FIG. 7B is 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 WKD...Wafer cassette drive unit MPU...Microprocessor ROM...Read-only memory RAM...Random access Memory KS...Support plate CT...Hinge mechanism

Claims (1)

[Claims] 1. A support member that supports each of a plurality of wafer cassettes;
A wafer processing apparatus comprising at least one bendable mechanism provided in a part of the support member for changing the orientation of the wafer cassette. 2. A patent in which the support member supports two wafer cassettes in a vertically stacked manner, and the bendable mechanism includes a hinge mechanism that tilts the upper half of the support member and the upper wafer cassette backward. A wafer processing apparatus according to claim 1.