JP3312748B2 - Wafer inspection apparatus and wafer inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer inspection apparatus,
In particular, the present invention relates to a wafer inspection apparatus for inspecting electrical characteristics of a large number of semiconductor element circuits formed on a semiconductor wafer.

[0002]

2. Description of the Related Art A semiconductor wafer has a large number of identical electric element circuits formed on its surface. Before cutting the electric element circuits into individual chips, a wafer prober is used to inspect the formation quality of each electric element circuit. A good or bad is determined for each electric element circuit by a wafer inspection apparatus called.

[0003] The wafer inspection apparatus includes a cassette storage unit, a wafer transfer unit, a table, a device control unit determination unit, and the like. A cassette accommodating a large number of wafers to be inspected is attached to the cassette accommodating section. The wafers are taken out of the cassette one by one by the wafer transport section and transported to the table. The table performs horizontal movement in the X-Y direction and vertical movement in the Z direction according to the element arrangement at the time of element inspection by sucking the wafer.

[0004] The device control section determination section includes a probe stage, a tester and the like. The probe stage has
A probe card corresponding to the wafer to be inspected is attached, and by contacting each electrode pad of the electric element circuit with a probe needle provided on the probe card, the formation quality of each electric element circuit is adjusted by the tester. The inspection is determined sequentially.

[0005] The wafer that has been inspected is transferred from the table to the cassette by the wafer transfer section and stored on the original shelf of the cassette.

[0006]

However, in the conventional wafer inspection apparatus, since a large number of wafers stored in one cassette are processed by one wafer inspection apparatus, the inspection time per cassette becomes long. There is a disadvantage that.
In addition, a plurality of wafer inspection apparatuses are provided, cassettes corresponding to the number of wafer inspection apparatuses are stored in the wafer stock unit, and wafers are taken out of the cassettes by the wafer transfer device, and wafer inspection corresponding to the wafers is performed. Although there is a wafer inspection apparatus that sequentially transports the wafer to the apparatus, this wafer inspection apparatus also has a disadvantage that the inspection time per cassette is long as described above.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wafer inspection apparatus capable of shortening the inspection processing time per cassette.

[0008]

In order to achieve the above object, the present invention provides a plurality of wafer inspection units arranged at predetermined intervals and a plurality of cassettes containing a large number of wafers to be inspected. A stockable cassette stock unit, and a first self-propelled cart movably arranged to take out the wafers stored in a predetermined cassette of the cassette stock unit one by one from the cassette and place it on a relay chuck. And transporting the wafer placed on the relay chuck to each of the plurality of wafer inspection units, and placing the wafer, which has been inspected by the wafer inspection unit, on the relay chuck so as to be movable so as to be movable. and second mobile carriage houses and conveyed to a cassette of the cassette stock part to said cassette the placed wafer after completion of the inspection to the relay chuck the first mobile carriage As well as controlled so, the wafer
After the inspection of the wafer by the inspection unit is completed, the
It takes time for a new wafer to be transferred
Removes wafers from the cassette attached to the wafer inspection unit.
A controller unit for controlling to take out and inspect;
It is characterized by having . In order to achieve the above object, the present invention provides a plurality of wafer inspection units arranged at predetermined intervals, a cassette stock unit capable of stocking a large number of cassettes containing a large number of wafers to be inspected, a cassette, A first self-propelled trolley movably disposed to take out the wafers stored in a predetermined cassette of the stock unit one by one from the cassette and place the wafers on the relay chuck, and place the wafers on the relay chuck; And a second self-propelled carriage movably arranged to carry the wafers to each of the plurality of wafer inspection units and to place the wafers inspected by the wafer inspection unit on the relay chuck. After the inspection is completed, the wafer placed on the relay chuck is transported by the first self-propelled carriage to the cassette in the cassette stock unit and stored in the cassette. The plurality of cassettes stocked in the first self-propelled carriage are arranged along a first transfer rail on which the first self-propelled carriage is movably movable, and the plurality of wafer inspection units are connected to the second self-propelled carriage. Are arranged along the second transfer rail movably arranged, and the wafer inspection by the wafer inspection unit is completed.
Later, a new wafer is transferred from the first self-propelled carriage.
If it takes time to that is attached to the upper blade inspection unit
Control to take out wafers from the cassette
And a controller unit that performs the operation. In order to achieve the above object, the present invention provides, among a plurality of cassettes stocked in a cassette stock unit, wafers to be inspected stored in a predetermined cassette one by one from the cassette by a first self-propelled carriage. The wafer is taken out, and the taken out wafer is placed on the relay chuck by the first self-propelled carriage, and the wafer placed on the relay chuck is placed in the second chuck.
The plurality of wafer inspection units are respectively transported by the self-propelled carriage, and the wafers that have been inspected by the plurality of wafer inspection units are taken out of the wafer inspection unit by the second self-propelled carriage, and the taken-out wafers are taken out of the second self-propelled carriage. The wafer is transported by the traveling carriage and placed on the relay chuck, and the wafer after inspection placed on the relay chuck is transported to the cassette in the cassette stock unit by the first self-propelled carriage and stored therein.
(C) after the inspection of the wafer by the inspection unit, the first self-propelled carriage
Where it takes time for a new wafer to be transferred from
The wafer from the cassette attached to the wafer inspection unit.
Is taken out and inspected .

[0009]

According to the present invention, first, of a plurality of cassettes stocked in the cassette stock section, wafers to be inspected stored in the first cassette are taken out one by one from the cassettes by the wafer transfer means. Each wafer is transported to a plurality of wafer inspection units. Next, in order from the wafers that have been inspected by the plurality of wafer inspection units, the wafers are transported to the original cassette by the wafer transport unit and stored therein, and the wafer to be inspected is taken out of the cassette and transferred to the inspected wafer inspection unit Transport.

As a result, the inspection processing time per cassette can be reduced by the number of wafer inspection units. For example, if eight wafer inspection units are installed, the inspection processing time can be reduced to 1/8 as compared with a conventional wafer inspection apparatus in which one wafer inspection unit inspects one cassette.
When the inspection of all the wafers stored in the first cassette is completed, the inspection of the wafer stored in the second cassette in the cassette stock unit is started. And the first
Is removed from the cassette stock unit and replaced with a new cassette containing the wafer to be inspected. In this way, the cassettes in which the wafer inspection has been completed are sequentially replaced with new cassettes and sequentially sent to the subsequent process.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a wafer inspection apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In FIG.
FIG. 1 is a top view showing an embodiment of a wafer inspection apparatus 10 according to the present invention.
2. It comprises a cassette stock unit 14, a wafer transfer unit 16, and a controller unit 18.

[Wafer Inspection Unit 12] Wafer Inspection Unit 12
Are four wafer probers 22A, 22A on one side (upward in the figure) with the transfer rail 20 of the wafer transfer device 16 interposed therebetween.
B, 22C and 22D, and 4 on the other side (downward in the figure).
The wafer probers 22E, 22F, 22G, and 22H are arranged in parallel at predetermined intervals and opposed to each other. Also,
Four testers 24A, 24B, 24C and 24D are connected to wafer probers 22A to 22H at a ratio of two to one.

The wafer prober 22A includes a first wafer transfer section 26, a probe stage 28, and the like. The wafer transfer section 26 supplies the wafer transferred by a self-propelled carriage 30 of the wafer transfer apparatus 16 described later to a supply section 26a.
Is transferred to a table (not shown) disposed below the probe stage 28. The table is
At the time of element inspection by sucking the wafer, horizontal movement in the X-Y direction and vertical movement in the Z direction according to the element arrangement can be performed.

A probe card (not shown) corresponding to a wafer to be inspected is attached to the probe stage 28, and each electrode pad of the electric element circuit is brought into contact with a probe needle provided on the probe card. Thus, the formation quality of each electric element circuit is sequentially inspected and determined by the tester 24A. The inspected wafer is transferred by the first wafer transfer unit 26 to the supply unit 26a. When the wafer is transferred to the supply unit 26a, a signal indicating the completion of the transfer is output to the controller unit 18.

A cassette storage section 32 is provided in the wafer prober 22A. A cassette 34 in which a large number of wafers to be inspected are stored is attached to the cassette storage section 32. The wafers are taken out of the cassette 34 one by one by a second wafer transfer unit (not shown) provided in the wafer prober 22A and transferred to the table.

Since the configuration of the wafer probers 22B to 22H is the same as the configuration of the wafer prober 22A described above, the description is omitted. [Cassette stock unit 14] Cassette stock unit 14
In the figure, four cassettes 36A, 36B, 36C and 36D each containing a large number of wafers to be inspected are arranged at predetermined intervals in the depth direction in the drawing. These cassettes 36A to 36D can be moved up and down in the depth direction in the figure by an elevating device (not shown) provided in the cassette stock unit 14.

The driving of the lifting device is controlled by the controller 18 described above. [Wafer transfer device 16] The wafer transfer device 16
Transport rail 20 disposed in the direction
And a transport rail 38 disposed in the Y direction orthogonal to the drawing.
A self-propelled carriage 40 is disposed on the transport rail 38 so as to be able to travel. Further, a wafer relay chuck 41 is provided near the self-propelled carriage 40.

As shown in FIG. 2, the self-propelled chassis 30 includes a chassis main body 42 and a robot unit 44. The chassis main body 42 is movably attached to the transport rail 20, and travels along the transport rail 20 by rotating wheels connected to a forward / reverse drive motor provided inside the chassis main body 42. can do. On the other hand, the robot unit 44 includes a chucking transfer unit 46 and a suction unit 4.
And 8. The chucking transfer section 46 has a drive motor 50 fixed on the chassis main body 42, and a transfer jig 52 is connected to the drive motor 50.
The transfer jig 52 can be turned 180 degrees while being moved in the direction of the arrow in the figure by driving the drive motor 52. A wafer chucking arm 54 is fixed to the transfer jig 52. The wafer chucking arm 54 can hold the wafer 56 and place it on the transfer chuck 58 of the suction unit 48.

The wafer 56 placed on the delivery chuck 58 is placed on the delivery chuck 58 at the same time as the wafer 56 is placed.
, And descends, and is stably held on the plate portion 60.
The configuration of the self-propelled chassis 40 is the same as that of the chassis main body 42 described above.
And the chucking transfer section 46, and a description thereof will be omitted. In addition, the traveling direction and traveling distance of the self-propelled undercarriages 30 and 40, the drive motor 50, and the vertical movement of the delivery chuck 58 are controlled by the controller 18.

Next, a control method by the controller 18 of the wafer inspection apparatus 10 configured as described above will be described. First, the self-propelled chassis 40 is moved to the position shown in FIG. Next, the robot unit 44 of the self-propelled undercarriage 40 and the elevating device of the cassette 36A are controlled, and the wafers 56 to be inspected stored in the cassette 36A are taken out one by one from the cassette 36A by the wafer chucking arm 54 and transferred. The jig 52 is rotated by 180 ° and placed on the relay chuck 41.

Next, the self-propelled chassis 30 is moved to the right end in FIG. Then, the robot unit 44 and the suction unit 48 of the self-propelled undercarriage 30 are controlled to hold the wafer 56 placed on the relay chuck 41 by the wafer chucking arm 54 of the self-propelled undercarriage 30, and to perform a transfer process. The tool 52 is rotated by 180 °, placed on the delivery chuck 58, and adsorbed by the delivery chuck 58. The delivery chuck 58 is lowered and held on the plate part 60.

Next, the self-propelled undercarriage 30 is moved leftward in FIG. 1 and stopped at the position of the wafer transfer section 26 of the wafer prober 22A. Then, the transfer chuck 58 is raised to separate the wafer 56 from the plate portion 60, and
After holding the wafer 56 by the wafer chucking arm 54, the transfer jig 52 is rotated clockwise by 90 ° and placed on the supply unit 26 a of the wafer transfer unit 26. The wafer 56 placed on the supply unit 26a is
Is transported to the table and inspected.

Thus, the remaining wafer prober 2
The wafers 5 of the cassette 36A are also used for 2B to 22H.
, 56,... Respectively, and each wafer prober 22B
Inspection is started from to 22H. Next, of the wafer probers 22A to 22H, the inspected wafer 56 is
When the wafers are transported to the supply units 26a of the wafer probers 22A to 22H, the wafers 56 whose inspection has been completed are sequentially performed from the wafer 56.
The wafer is transferred to and stored in the cassette 36A by the wafer transfer device 16. Since the wafer storage procedure by the wafer transport device 16 is the reverse of the wafer transport procedure described above,
The description is omitted.

After the transfer and storage of the wafer 56 are repeated, when the inspection of all the wafers 56 in the cassette 36A is completed, the inspection of the wafer 56 stored in the cassette 36B is started. Then, the user removes the cassette 36A from the cassette stock unit 14 and replaces the cassette 36A with a new cassette containing the wafer to be inspected. in this way,
The cassettes for which the wafer inspection has been completed are exchanged for new cassettes in order, and are sequentially sent to the subsequent processes.

Thus, in this embodiment, the inspection processing time per cassette can be reduced by the number of wafer inspection units. For example, when eight wafer probers 22A to 22H are installed as in this embodiment, the inspection processing time is reduced to 1/8 as compared with a conventional wafer inspection apparatus in which one wafer prober inspects one cassette. Can be shortened.

In the present embodiment, the inspection process for one type of wafer 56 has been described. However, the present invention is not limited to this, and when different types of wafers are stored in each of the cassettes 36A to 36D. The wafer probers 22A to 22H may be divided for each of the testers 24A to 24D and set so as to correspond to the type of wafer. Also, the wafer 5
If it takes time for the new wafer 56 to be transferred from the wafer transfer device 16 after the completion of the inspection in Step 6, the wafer may be taken out from the cassette 34 mounted on each of the wafer probers 22A to 22H and inspected. . As a result, the wafer inspection process can be performed efficiently.

Further, each of the wafer probers 22A to 22H
A wafer chucking arm may be provided to transfer the wafer 56 attracted to the transfer chuck 58 to the wafer probers 22A to 22H by the wafer chucking arm.

[0028]

As described above, according to the present invention, of a plurality of cassettes stocked in the cassette stock unit, a wafer to be inspected stored in a predetermined cassette can be used.
The first self-propelled carriage removes the wafers one by one from the cassette and places them on a relay chuck. The wafers placed on the relay chucks are transported by the second self-propelled carriage to a plurality of wafer inspection units. The wafer that has been inspected by the wafer inspection unit is placed on the relay chuck, and the inspected wafer is transported by the first self-propelled carriage to the cassette in the cassette stock unit and stored. As a result, the wafer inspection process can be performed efficiently. Further, as compared with a conventional wafer inspection apparatus in which one wafer inspection unit inspects one cassette, the inspection processing time per cassette can be greatly reduced. Further, inspection of the wafer is completed.
Later, a new wafer is transferred from the first self-propelled carriage.
If it takes a long time, the camera attached to the wafer inspection unit
Efficient because the wafer is taken out of the set and inspected
A wafer inspection process can be performed.

[Brief description of the drawings]

FIG. 1 is a top view showing an embodiment of a wafer inspection apparatus according to the present invention.

FIG. 2 is a front view of a wafer transfer cart applied to the wafer inspection apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Wafer inspection apparatus 12 ... Wafer inspection part 14 ... Cassette stock part 16 ... Wafer transfer device 18 ... Controller part 22A, 22B, 22C, 22D, 22E, 22F, 2
2G, 22H: Wafer prober 30, 40: Self-propelled carriage 36A, 36B, 36C, 36D: Cassette

Claims (3)

(57) [Claims] A plurality of wafer inspection units arranged at predetermined intervals; a cassette stock unit capable of stocking a large number of cassettes accommodating a large number of wafers to be inspected; and a predetermined cassette of the cassette stock unit. A first self-propelled carriage movably arranged to take out the stored wafers one by one from the cassette and mounting the wafer on the relay chuck, and a plurality of the wafers mounted on the relay chuck. conveys each wafer inspection unit, and a second mobile carriage wafers examined completed in wafer inspection unit is arranged capable of traveling movement of mounting to the relay chuck, mounted on the relay chuck inspection The control is performed such that the wafer after completion is transported by the first self-propelled carriage to the cassette in the cassette stock unit and stored in the cassette.
After the wafer inspection by the wafer inspection unit is completed, the first
It takes time for a new wafer to be transferred from the carriage
If not, remove the cassette from the wafer inspection unit.
Control to take out and inspect the wafer
Wafer inspection apparatus characterized by having a La unit. A plurality of wafer inspection units arranged at predetermined intervals; a cassette stock unit capable of stocking a large number of cassettes accommodating a large number of wafers to be inspected; and a predetermined cassette of the cassette stock unit. A first self-propelled carriage movably arranged to take out the stored wafers one by one from the cassette and mounting the wafer on the relay chuck, and a plurality of the wafers mounted on the relay chuck. A second self-propelled carriage movably arranged to carry the wafers, which have been inspected by the wafer inspection unit, to the relay chuck, respectively, while being transported to the wafer inspection unit; The wafer after the inspection is transported by the first self-propelled carriage to the cassette in the cassette stock unit and stored in the cassette, and is stored in the cassette stock unit. Several cassettes are arranged along a first transfer rail on which the first self-propelled carriage is movably movable, and the plurality of wafer inspection units are capable of traveling the second self-propelled carriage. disposed along a second transfer rail disposed, after the inspection of the wafer by the wafer inspection unit, the first
It takes time for a new wafer to be transferred from the self-propelled carriage.
In such a case, the cassette mounted on the wafer inspection unit
Control to take out and inspect wafers
Wafer inspection apparatus characterized by comprising: a chromatography la section. 3. A plurality of cassettes stocked in a cassette stock section, wafers to be inspected stored in a predetermined cassette are taken out one by one from the cassettes by a first self-propelled carriage, and the taken out wafers are taken out. Is mounted on the relay chuck by the first self-propelled carriage, and the wafer mounted on the relay chuck is transferred to a plurality of wafer inspection units by the second self-propelled carriage, respectively. The wafer, which has been inspected by the inspection unit, is taken out of the wafer inspection unit by the second self-propelled carriage, the taken-out wafer is transported by the second self-propelled carriage, mounted on the relay chuck, and mounted on the relay chuck. the wafer after completion of the inspection that is location and stored conveyed to a cassette of the cassette stock part by the first mobile carriage, after the inspection of the wafer by the wafer inspection unit, Serial first
It takes time for a new wafer to be transferred from the self-propelled carriage.
In such a case, the cassette mounted on the wafer inspection unit
And inspecting the wafer by taking out the wafer from the wafer.