JP2019169546A - Wafer transfer apparatus for prober - Google Patents

Abstract

To provide a wafer transfer apparatus for prober, capable of suppressing generation of a jumping phenomenon when retention of a wafer W is released.SOLUTION: The wafer transfer apparatus for prober includes an electropneumatic regulator 60 provided on an air supply passage 54 connecting a Bernoulli chuck 38 of a transfer arm 20 with a compressor 52. The electropneumatic regulator 60 is controlled by a signal control section 66 so that a pressure of the compressed air supplied from the compressor 52 to the Bernoulli chuck 38 lowers gradually.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a prober that performs electrical inspection of a plurality of chips formed on a semiconductor wafer, and more particularly to a wafer transfer apparatus that transfers a semiconductor wafer within the prober.

  In the semiconductor manufacturing process, a semiconductor wafer (hereinafter referred to as a wafer) is subjected to various processes to form a plurality of chips having devices. Each chip is inspected for electrical characteristics and then divided by a dicer, and then fixed to a lead frame or the like and assembled. The inspection of electrical characteristics is performed by an inspection unit of a prober (see, for example, Patent Document 1). In the inspection unit, the wafer is held on the wafer chuck, and the probe is brought into contact with the electrode pad of each chip. The prober tester supplies power and various test signals from a terminal connected to the probe to the chip, and analyzes the signals output to the electrodes of the chip to confirm whether or not it operates normally.

  In the prober, uninspected wafers are stored in a wafer cassette. From this state, the wafers are held by the holding unit of the transfer arm and transferred from the wafer cassette to the inspection unit. In addition, the wafer that has been inspected is held by the holding portion of the transfer arm, returned from the inspection portion to the wafer cassette, and stored. Patent Document 1 discloses that the lower surface of an uninspected wafer is held (supported) by a transfer arm without suction.

JP, 2006-192484, A

  Wafers, which are semiconductor manufacturing apparatuses, tend to be thinned in recent years due to lighter products and improved characteristics, and some of them are warped during the manufacturing process. When a warped wafer is held by the transfer arm disclosed in Patent Document 1, the warpage is temporarily corrected to be flat when holding, but the original warpage is reproduced on the wafer when the holding is released. Therefore, a phenomenon that the wafer jumps with respect to the transfer arm at that time occurs.

  When such a jump occurs in the wafer, the wafer is displaced in the transfer arm, so that the positioning accuracy of the wafer with respect to the inspection unit deteriorates, or the wafer comes into contact with other members and is damaged. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a prober wafer transfer device capable of suppressing the wafer jumping that occurs when the wafer is released.

  In order to achieve the object of the present invention, a prober wafer transfer apparatus of the present invention is provided with a transfer arm for transferring a wafer, and a chuck that is provided on the transfer arm and holds the wafer in a non-contact manner by discharging air. A compressed air supply source, an air supply channel connecting the chuck unit and the compressed air supply source, and an air pressure control unit provided in the air supply channel, the compressed air supply source to the chuck unit By adjusting the pressure of the supplied compressed air, it is connected to the air pressure adjusting unit that can change the holding force of the chuck unit with respect to the wafer, and is supplied to the chuck unit from the compressed air supply source. And a control unit that controls the air pressure adjusting unit so that the pressure of the compressed air gradually decreases.

  In one embodiment of the present invention, the air pressure adjusting unit is an electropneumatic regulator that adjusts the pressure of compressed air supplied from a compressed air supply source to the chuck unit, and the control unit is a level of an electric signal applied to the electropneumatic regulator. It is preferable that it is a signal control part which reduces gradually.

  According to one aspect of the present invention, the air pressure adjustment unit is provided in a plurality of branch channels branched from the air supply channel and connected to the chuck unit, and a plurality of branch channels, each having a different amount of restriction. A throttle valve, and a valve that is provided between the air supply channel and the plurality of branch channels, and selectively switches one branch channel connected to the air supply channel from among the plurality of branch channels And the control unit is a valve control unit that controls the valve so as to switch the branch flow path from the branch flow path of the throttle valve having a small throttle amount to the branch flow channel of the throttle valve having a large throttle amount. preferable.

  According to the present invention, it is possible to suppress the splashing of the wafer that occurs when the holding of the wafer is released.

Overall perspective view showing the configuration of the prober of the embodiment Plan view of relevant parts showing the configuration of the transfer arm Explanatory drawing showing the pneumatic circuit of the compressed air supply device of Bernoulli chuck Explanatory drawing which showed the state of the wafer by the wafer conveyance device of an embodiment Explanatory drawing which showed the pneumatic circuit of the compressed air supply apparatus of other embodiment.

  Hereinafter, preferred embodiments of a wafer transfer apparatus for a prober according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a prober 10 to which the wafer conveyance device of the embodiment is applied.

  A prober 10 shown in FIG. 1 includes a prober body 12 and a loader unit 14 adjacent to the prober body 12. In FIG. 1, the loader unit 14 is shown in a transparent manner to show a schematic structure inside the loader unit 14.

  The loader unit 14 shown in FIG. 1 includes a load port 16 on which a wafer cassette 18 is placed, a transfer arm 20 constituting a wafer transfer device, a pre-alignment stage 22 and the like.

  An uninspected wafer W stored in the wafer cassette 18 (in FIG. 1, the wafer W is shown at a position above the wafer cassette 18 for easy understanding) is moved in the direction of arrow A. The lower surface is held by 20. Thereafter, the wafer W is taken out of the wafer cassette 18 by the movement of the transfer arm 20 in the direction of arrow B and transferred to the pre-alignment stage 22.

  The pre-alignment stage 22 includes a sub chuck 24, a pre-alignment sensor 26, a load sensor 28, a lift device (not shown), a centering device (not shown), and the like. Is pre-aligned at a predetermined position.

  The pre-aligned wafer W is held again by the transfer arm 20 and then transferred to the inspection unit 34 of the prober body 12 by the movement of the transfer arm 20 in the direction of arrow C. Here, the wafer W is subjected to electrical inspection of a chip using a probe card (not shown). When the electrical inspection is completed, the wafer W is held again by the transfer arm 20 and then returned to the loader unit 14 by the operation of the transfer arm 20 in the direction of arrow D. Thereafter, the wafer W is moved in the direction of arrow A. It is stored in the wafer cassette 18 by the operation.

  FIG. 2 is a main part plan view showing the configuration of the transfer arm 20.

  As shown in FIG. 2, the transfer arm 20 has a ring-shaped holding portion 34 at the tip. A flat surface 36 of the holding unit 34 has a Bernoulli chuck 38 that holds the wafer W. The Bernoulli chuck 38 is a non-contact type chuck member that holds the wafer W by the Bernoulli effect by discharging compressed air from a chuck opening 38 </ b> A formed in the transfer arm 20. The Bernoulli chuck 38 is an example of a chuck portion that is a component of the present invention.

  A plurality of Bernoulli chucks 38 (six in the example of FIG. 2) are arranged at predetermined positions on the surface 36 of the holding portion 34. A plurality of rubber pads 40 are arranged on the surface 36 of the holding portion 34 so as to surround the Bernoulli chuck 38. These pads 40 are attached to the surface 36 so as to protrude by a predetermined amount with respect to the surface 36.

  According to the transfer arm 20 configured as described above, when the compressed air is discharged from the chuck opening 38A of the Bernoulli chuck 38, a negative pressure generated in the gap between the surface 36 of the holding unit 34 and the lower surface of the wafer W. As a result, the wafer W is attracted to the surface 36 of the holding portion 34 and brought into contact with the pad 40. Thereby, according to the transfer arm 20 of the embodiment, the wafer W can be held in contact with the pad 40.

  FIG. 3 is an explanatory diagram showing a pneumatic circuit of the compressed air supply device 50 that operates the Bernoulli chuck 38.

  As shown in FIG. 3, the compressed air supply device 50 includes an air supply channel 54 that supplies the compressed air from the compressor 52 to the Bernoulli chuck 38. As an example, the compressed air supply device 50 includes a regulator 56, a directional control valve 58 including an electromagnetic valve, an electropneumatic regulator 60, a flow meter 62, and an in-line filter 64. It comprises by providing in order toward the downstream from the upstream side.

  The compressor 52 is an example of a compressed air supply source that is one of the components of the present invention. The regulator 56 has a function of adjusting the compressed air from the compressor 52 to a pressure suitable for the Bernoulli chuck 38. The direction control valve 58 includes an A port 58A and a B port 58B, and has a function of selectively switching the flow path between the A port 58A and the B port 58B. When the direction control valve 58 is switched to the A port 58A side, the air supply passage 54 is opened, and the compressed air of the compressor 52 is supplied to the Bernoulli chuck 38. Further, as shown in FIG. 4, when the direction control valve 58 is switched to the B port 58B side, the air supply flow path 54 is shut off at the position of the direction control valve 58, so that the compressor 52 to the Bernoulli chuck 38 The supply of compressed air is stopped.

  The electropneumatic regulator 60 has a function of adjusting the pressure of the compressed air supplied from the compressor 52 to the Bernoulli chuck 38 continuously (steplessly) or stepwise. The electropneumatic regulator 60 is an example of an air pressure adjusting unit that is one of the components of the present invention.

  The electropneumatic regulator 60 is connected to the signal control unit 66, and adjusts the pressure of the compressed air supplied to the Bernoulli chuck 38 based on the level of the electric signal supplied from the signal control unit 66 as described above. Can do. The signal control unit 66 is an example of a control unit that is one of the components of the present invention.

  The signal control unit 66 functions as a part of a control device (not shown) that controls the prober 10 in an integrated manner, and when the transfer arm 20 holds the wafer W, and when the transfer arm 20 releases the hold of the wafer W. In addition, a signal indicating a holding operation and a signal indicating a releasing operation are provided from the above-described control device.

  When a signal indicating the holding operation is given from the control device, the signal control unit 66 gives an electric signal of a level corresponding to the holding to the electropneumatic regulator 60. Further, when a signal indicating the release operation is given from the control device, the signal control unit 66 gradually lowers the level of the electric signal given to the electropneumatic regulator 60 from the level corresponding to the holding to the level corresponding to the release. .

  The change in pressure by the electropneumatic regulator 60 can be confirmed by looking at the numerical value displayed on the flow meter 62.

  Next, the operation of the compressed air supply device 50 configured as described above will be described. FIG. 4 shows a state of the wafer W when the warped wafer W is held and released by the transfer arm 20 of the embodiment.

  As shown in the upper diagram of FIG. 4, when the wafer W is placed on the holding unit 34 of the transfer arm 20, a signal indicating the holding operation is given from the control device to the signal control unit 66 (see FIG. 4). Then, the signal control unit 66 gives the electropneumatic regulator 60 an electric signal of a level corresponding to the holding. As a result, compressed air having a pressure corresponding to the holding is discharged from the Bernoulli chuck 38, and the wafer W is elastically deformed (warping is corrected) and held by the holding unit 34 as shown in the middle diagram of FIG. 4.

  Next, when a signal indicating the release operation is given from the control device to the signal control unit 66, the signal control unit 66 changes the level of the electric signal supplied to the electropneumatic regulator 60 from the level corresponding to the holding to the release. Gradually lower to the desired level. As a result, the pressure of the compressed air discharged from the Bernoulli chuck 38 gradually decreases, so that the wafer W held in an elastically deformed state in the holding unit 34 is, as shown in the lower diagram of FIG. Without bouncing on 34, the shape gradually returns from the shape indicated by the two-dot chain line to the shape indicated by the solid line with the original warp.

  Therefore, according to the wafer transfer apparatus of the embodiment, the electropneumatic regulator 38 (air pressure adjustment) is connected to the air supply channel 54 that connects the Bernoulli chuck 38 (chuck part) of the transfer arm 20 and the compressor 52 (compressed air supply source). Since the signal control unit 66 (control unit) controls the electropneumatic regulator 38 so that the pressure of the compressed air supplied from the compressor 52 to the Bernoulli chuck 38 gradually decreases, the holding of the wafer W is released. The bounce phenomenon that sometimes occurs can be suppressed. Thereby, according to the wafer conveyance device of the embodiment, the problem that the wafer W is displaced in the conveyance arm 20 or the wafer W is in contact with other members and is damaged can be solved.

  Next, another embodiment of the compressed air supply device will be described. FIG. 5 is an explanatory diagram showing a pneumatic circuit of the compressed air supply device 70 of another embodiment, and the same components as those of the compressed air supply device 50 shown in FIG. Is omitted.

  The compressed air supply device 70 shown in FIG. 5 includes an air supply channel 54 that supplies the compressed air from the compressor 52 to the Bernoulli chuck 38. As an example, the compressed air supply device 70 includes a regulator 56 and an air pressure adjustment unit 72 in the air supply flow path 54 in order from the upstream side to the downstream side of the airflow.

  The air pressure adjusting unit 72 shown in FIG. 5 has a plurality of (three in FIG. 5) branch channels 74, 76, and 78. These branch flow paths 74, 76, and 78 are branched from the air supply flow path 54 and connected to the Bernoulli chuck 38.

  The air pressure adjustment unit 72 includes throttle valves 80, 82, and 84 provided in the branch flow paths 74, 76, and 78, respectively. These throttle valves 80, 82, 84 have different throttle amounts, for example, the throttle amount of the throttle valve 80 is the smallest, the throttle amount of the throttle valve 84 is the largest, and the throttle amount of the throttle valve 82 is the same. It is set in the middle. Further, the throttle amount of the throttle valve 80 is set to a throttle amount that enables the Bernoulli chuck 38 to hold the wafer W. However, the throttle amount of each of the throttle valves 82 and 84 allows the wafer W to be released. The amount is set.

  The air pressure adjusting unit 72 includes directional control valves 86, 88, and 90 provided in the branch flow paths 74, 76, and 78, and a valve control unit that controls operations of the directional control valves 86, 88, and 90, respectively. 92.

  The directional control valves 86, 88, and 90 are connected to the air supply flow channel 54 through one branch flow channel (one of the branch flow channels 74, 76, and 78). The valve can be selectively switched between 76 and 78. The directional control valves 86, 88, 90 configured in this way are valves provided between the air supply channel 54 and the branch channels 74, 76, 78, and select one branch channel. Has substantially the same function as the valve. Therefore, the direction control valves 86, 88, and 90 constitute a valve that is a component of the present invention.

  The valve control unit 92 functions as a part of a control device (not shown) that controls the prober 10 in an integrated manner, and when the transfer arm 20 holds the wafer W, and when the transfer arm 20 releases the hold of the wafer W. In addition, a signal indicating a holding operation and a signal indicating a releasing operation are provided from the above-described control device.

  When a signal indicating the holding operation is given from the control device, the valve control unit 92 selects the branch channel 74 provided with the throttle valve 80 corresponding to the holding, and the branch channel 74 is connected to the air supply channel 54. The direction control valves 86, 88, and 90 are operated so that Specifically, the A port 86A of the directional control valve 86 is connected to the branch flow path 74A on the downstream side of the directional control valve 86, and the B ports 88B and 90B of the directional control valves 88 and 90 are connected to the directional control valve 88, It connects to the branch flow paths 76A and 78A on the downstream side of 90. As a result, the branch flow path 74 is connected to the air supply flow path 54. The branch flow paths 74A, 76A, 78A are part of the branch flow paths 74, 76, 78.

  Further, when a signal indicating the release operation is given from the control device, the valve control unit 92 selects the branch flow paths 74 and 76 having the throttle valves 82 and 84 corresponding to the release, and the branch flow paths 76 and 78 are selected. The direction control valves 86, 88, and 90 are operated so as to be connected to the air supply flow path 54 in order. Specifically, the B port 86B of the direction control valve 86 is connected to the branch flow path 74A, and the A port 88A of the direction control valve 88 is connected to the branch flow path 76A. Thereafter, the B port 88B of the direction control valve 88 is connected to the branch flow path 76A, and the A port 90A of the direction control valve 90 is connected to the branch flow path 78A. Thereby, the branch flow paths 76 and 78 are connected to the air supply flow path 54 in order.

  Next, the operation of the compressed air supply device 70 shown in FIG. 5 will be described with reference to FIG.

  As shown in the upper diagram of FIG. 4, when the wafer W is placed on the holding unit 34 of the transfer arm 20, a signal indicating the holding operation is given from the control device to the valve control unit 92. Then, the valve control unit 92 selects the branch flow path 74 provided with the throttle valve 80 corresponding to the holding, and the direction control valves 86, 88, 90 so that the branch flow path 74 is connected to the air supply flow path 54. Is operated as described above. That is, the A port 86A of the direction control valve 86 is connected to the branch flow path 74A, and the B ports 88B and 90B of the direction control valves 88 and 90 are connected to the branch flow paths 76A and 78A. As a result, the branch flow path 74 is connected to the air supply flow path 54, and compressed air having a pressure corresponding to the holding is discharged from the Bernoulli chuck 38, so that the wafer W is elastic as shown in the middle diagram of FIG. It is deformed (warping is corrected) and held by the holding portion 34.

  Next, when a signal indicating the release operation is given from the control device to the valve control unit 92, the valve control unit 92 selects the branch flow paths 74 and 76 including the throttle valves 82 and 84 corresponding to the release, and branches. The direction control valves 86, 88, 90 are operated as described above so that the flow paths 76, 78 are sequentially connected to the air supply flow path 54. That is, the B port 86B of the direction control valve 86 is connected to the branch flow path 74A, and the A port 88A of the direction control valve 88 is connected to the branch flow path 76A. Thereafter, the B port 88B of the direction control valve 88 is connected to the branch flow path 76A, and the A port 90A of the direction control valve 90 is connected to the branch flow path 78A. As a result, the pressure of the compressed air discharged from the Bernoulli chuck 38 decreases stepwise, so that the wafer W held in the elastically deformed state in the holding portion 34 is, as shown in the lower diagram of FIG. Without jumping on the holding portion 34, the shape gradually returns from the shape indicated by the two-dot chain line to the shape indicated by the solid line with the original warp.

  Therefore, according to the wafer transfer apparatus of FIG. 5, the throttle valves 80, 82, 84 and the direction control valves 86, 88, which have different throttle amounts, are branched into the branch channels 74, 76, 78 branched from the air supply channel 54. 90, and the valve controller 92 controls the direction so that the branch channel is switched from the state in which the branch channel 74 is connected to the Bernoulli chuck 38 to the branch channels 76 and 78 of the throttle valves 82 and 84 having a large throttle amount. Since the valves 86, 88, and 90 are controlled, it is possible to suppress the bounce phenomenon that occurs when the holding of the wafer W is released. Thereby, according to the wafer transfer apparatus of FIG. 5, the problem that the wafer W is displaced in the transfer arm 20 or the wafer W comes into contact with other members and is damaged can be solved.

  The prober wafer transfer apparatus according to the embodiment has been described in detail above, but the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the scope of the present invention. Of course it is good.

W ... wafer, 10 ... prober, 12 ... prober body, 14 ... loader section, 16 ... load port, 18 ... wafer cassette, 20 ... transfer arm, 22 ... pre-alignment stage, 24 ... sub-chuck, 26 ... pre-alignment sensor, 28 ... Stock sensor, 34 ... Holding part, 36 ... Surface, 38 ... Bernoulli chuck, 40 ... Pad, 50 ... Compressed air supply device, 52 ... Compressor, 54 ... Air supply flow path, 56 ... Regulator, 58 ... Direction control Valve, 60 ... Electro-pneumatic regulator, 62 ... Flow meter, 64 ... In-line filter, 70 ... Compressed air supply device, 72 ... Air pressure adjusting unit, 74, 76, 78 ... Branch channel, 80, 82, 84 ... Throttle valve , 86, 88, 90 ... direction control valve, 92 ... valve control unit

Claims (3)

A transfer arm for transferring a wafer;
A chuck portion that is provided on the transfer arm and holds the wafer in a non-contact manner by discharging air;
A compressed air source;
An air supply flow path connecting the chuck portion and the compressed air supply source;
An air pressure control unit provided in the air supply flow path, wherein a holding force of the chuck unit with respect to the wafer is adjusted by adjusting a pressure of the compressed air supplied from the compressed air supply source to the chuck unit. A changeable air pressure adjuster;
A control unit connected to the air pressure adjusting unit and controlling the air pressure adjusting unit so that the pressure of the compressed air supplied from the compressed air supply source to the chuck unit gradually decreases;
A prober wafer transfer device. The air pressure adjustment unit is an electropneumatic regulator that adjusts the pressure of the compressed air supplied to the chuck unit from the compressed air supply source,
The control unit is a signal control unit that gradually decreases the level of an electric signal applied to the electropneumatic regulator,
The prober wafer transfer apparatus according to claim 1. The air pressure adjuster is
A plurality of branch channels branched from the air supply channel and connected to the chuck portion,
A plurality of throttle valves provided in the plurality of branch channels, each having a different throttle amount;
A valve that is provided between the air supply channel and the plurality of branch channels and selectively switches one of the branch channels connected to the air supply channel from the plurality of branch channels. And having
The control unit is a valve control unit that controls the valve so as to switch the branch flow path from the branch flow path of the throttle valve having a small throttle amount to the branch flow path of the throttle valve having a large throttle amount. 2. The prober wafer transfer apparatus according to claim 1.

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