JPH0719809B2 - Wafer prober - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention measures various electrical characteristics of semiconductor elements (hereinafter, chips) formed on a surface of a semiconductor wafer (hereinafter, wafer). In particular, the present invention relates to a wafer prober equipped with an automatic transfer device for probe cards.

(Prior Art) A wafer prober measures the electrical characteristics of each of a large number of chips formed on a wafer and eliminates chips that have been determined to be defective before the assembly process, thus reducing costs and improving productivity. Is a device for contributing to.

By the way, recent semiconductor manufacturing processes are required to improve productivity, yield and quality.
As the size of wafers increases and automation of manufacturing equipment progresses, the same goes for probers.A prober that can measure automatically by setting a wafer cassette containing wafers is available. Being developed.

However, due to the high integration of chips and the increase in the number of products in recent years, the number of small-quantity and multi-product production processes is increasing, and the number of operations by the operator is greatly increasing.
In particular, the probe card needs to be exchanged for each specific target chip type. For example, when measuring X type chips and then measuring Y type chips, the probe card is used according to the Y type. Need to be replaced.

Conventionally, in such a probe card exchange means, an operator loosens a screw or the like on the head plate to remove the probe card, and then attaches a probe card suitable for the Y type, and the like. Was done by artificial means.

(Problems to be Solved by the Invention) However, as described above, in the conventional wafer prober, the operator artificially replaces the probe card every time the type of wafer is replaced, which conflicts with automation in the semiconductor manufacturing process. Of course, it is extremely difficult to improve productivity, yield, variety, etc.

In particular, the probe stylus of a probe card lacks durability due to friction against the tip, so in order to obtain highly reliable measurement results, the probe card must be replaced frequently, and therefore the operator must check the probe card one by one. This requires a lot of time for replacement and selection of product types, which not only hinders the reduction of work time, but also causes the operator to drop the probe card during transportation while installing the probe card and damage it. I was afraid.

Therefore, the present invention has been made to solve the above-mentioned problems, by automating the probe card transport system, facilitating full automation of the prober, and improving productivity, yield, and probe card replacement. An object of the present invention is to provide a wafer prober capable of improving safety.

[Structure of the Invention] (Means for Solving Problems) A wafer prober of the present invention is a wafer for measuring by contacting a stylus mounted on a probe card with electrode pads of semiconductor elements formed in large numbers on a semiconductor wafer. In the prober,
A plurality of types of the probe card can be arranged at predetermined positions, and the probe card can be automatically exchanged through a transfer mechanism including an expandable arm that takes out the probe card according to a preset program and transfers the probe card to the insert ring. It is characterized by being configured as described above.

(Working) With the telescopic arm that is vertically movable in the prober body and movable in the direction of rotation, hold the desired probe card from the multiple probe cards stored in the card storage shelf and transport it to the insert ring. As a result, the card carrier system can be fully automated when the probe card is exchanged, the prober can be easily automated, and the productivity, the yield, and the safety when the probe card is exchanged can be improved.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing the outer appearance of a wafer prober of the embodiment,
Reference numeral 1 is a main stage of the wafer prober, and 2 is a loader stage of the wafer prober.

Wafer cassettes 3a and 3b for accommodating wafers are arranged in the loader stage 2. For example, when measuring a wafer in the wafer cassette 3a, the wafer is taken out from the wafer cassette 3a by a wafer transfer mechanism (not shown). The wafer that has been transferred to the measurement position and the measurement of which has been completed is transferred to the wafer cassette 3b and stored in the reverse order.

Reference numeral 4 is a test head, which is rotatably attached by a rotary shaft 5 that is an attachment portion with the prober main body.
A ring-shaped insert ring 6 is provided at the center of the upper surface of the main stage 1, and a probe card is mounted on the insert ring 6. During wafer measurement,
The test head 4 is in close contact with the main stage 1, and the detection signal detected by the stylus of the probe card at this time is the probe card, the insert ring 6,
It is transmitted to a prober tester (not shown) via a measurement circuit in the test head 4.

On the other hand, on the left side of the main stage 1, a card storage rack 7 that stores a plurality of probe cards, and a desired probe card is automatically taken out from the card storage rack 7 to the probe card mounting position, that is, the lower surface of the insert ring 6. An automatic probe card transport mechanism 8 for transporting this is provided.

FIG. 2 is a view showing a more detailed structure of the probe card automatic transfer mechanism 8 and the lower surface of the test head 4, in which a plurality of probe cards 9 are provided in the probe card accommodation rack 7.
Is housed.

Reference numeral 21 is a base of the probe card automatic transfer mechanism, and a rotary base 22 is arranged on the base 21 with a gap therebetween.

An expandable telescopic arm, for example, an expandable arm 23 having a structure in which a large number of links are connected to each other in an X shape by pivot pins is arranged on the rotary base 21.

The expandable arm drive screw 24 is attached to the rotary base 21 at both ends thereof by sliding support members 25a and 25b in parallel with the expandable direction of the expandable arm 23. A ball nut 26 is screwed into the telescopic arm driving screw 24, and the ball nut 26 and the support pin 27 of the telescopic arm 23 are connected by a nut connecting plate 28.

Further, a telescopic arm drive motor 29 is installed on the rotary base 22, and a gear 29a provided on the rotating shaft of this 29 and a gear 24a provided at one end of the telescopic arm drive screw 24 are a timing belt. It is connected by 30.

That is, the expansion and contraction operation of the expansion and contraction arm 23 transmits the rotation of the expansion and contraction arm drive motor 29 mounted on the rotation base 22 to the drive screw 24 via the timing belt 25, and this rotation causes the drive screw 24 to be screwed. By moving the ball nut 27, the nut connecting plate 29 that connects the ball nut 27 and the support pin 28 of the expandable arm 23 is moved.

A disk-shaped probe card mounting plate 31 is attached to the tip of the telescopic arm 23.
Are attached, and probe card support pins 32 are provided on the peripheral portion of the probe card at intervals of 120 degrees.

On the other hand, a rotary motor 33 is attached to the base 21, a gear is attached to the rotary shaft of the rotary motor 33, and the gear is provided in the gap between the rotary base 22 and the base 21. It is connected by a timing belt to the omitted rotary base rotary shaft. That is, the rotation base 22 is rotated by rotating the rotation motor 33.

By the way, the base 21 can be moved up and down in the Z-axis direction by a vertical drive mechanism. This vertical drive mechanism has three vertical guide shafts 34 vertically mounted on the main body of the prober, a vertical drive screw 35, and a vertical drive mechanism. It is composed of a motor 36.

A gear is attached to the rotation of the vertical drive motor 36, and this gear is connected to the gear inserted through the lower end of the vertical drive screw 35 via a timing belt.

Each of the three vertical guide shafts 34 penetrates a bearing member 38 provided on the base 21 and is vertically provided from the main body of the prober, and the penetrating portions have a slidable structure. A ball nut 37 is screwed onto the vertical drive screw 35, and the ball nut 37 is fixed to the base 21.

That is, in the ascending / descending structure of the base 21, by rotating the vertical drive screw 35 by the rotation of the vertical drive motor 36, the ball nut 37 integrated with the base 21 screwed to the vertical drive screw 35 moves up and down. It is done by doing.

The operation of such a probe card automatic transport device will be described.

First, the probe card 9 corresponding to the wafer type is selected based on the wafer type information programmed in advance in the memory mechanism of the prober CPU, and the probe card mounting plate 31 is stored in the card storing rack 7 and is selected. After extending the telescopic arm 23 so as to be inserted into the lower surface of the probe card 9, the vertical drive motor 36 is driven to raise the base 21, and the probe card 9 is mounted on the probe card mounting plate 31. Then, the probe card 9 is temporarily placed on a probe card alignment mechanism (not shown) for alignment.

After the alignment is completed, the probe card 9 is mounted again, the rotary motor 33 is driven to rotate the rotary base 22 by 90 degrees, and then the telescopic arm 23 is extended to insert the probe card 9 on the lower surface of the test head 4. The probe card 9 is conveyed to the lower surface of the ring 6, and then the vertical motor 36 is driven to raise the base 21 to bring the probe card 9 and the insert ring 6 into contact with each other. After that, the probe card 9 and the insert ring 6 are fixed by the probe card fixing mechanism.

By the way, although it is a probe card fixing mechanism, this may be a mechanism such as, for example, in this example, the test head 4
Positioning pins 42, which are respectively driven by a plurality of air cylinders 41, are arranged on the outer periphery of the insert ring 6 at a plurality of positions.
The positioning pin 42 presses the card holder 9a of the probe card 9 from the lower surface to fix it.

That is, radial fixing grooves 9b are provided at a plurality of locations on the lower surface of the card holder 9a, and the positioning pins 42 are fitted into the fixing grooves 9b.

As described above, according to the prober of the present invention, it is possible to transport the probe card to the insert ring of the test head completely automatically.Therefore, the operator does not accidentally drop and damage the probe card when transporting it. Further, when the work is fully automated, for example, when the attachment / detachment of the probe card and the insert ring is automated to achieve the complete automation of the work, this can be easily dealt with, and the production efficiency, the product type, and the yield can be improved.

Also, a scalar robot or the like may be used for the transport mechanism,
In this case, a plurality of types of probe cards may be mounted on the ring-shaped card mounting plate instead of the probe card storage shelf.

[Effects of the Invention] As described above, according to the wafer prober of the present invention, it greatly contributes to the complete automation of the work, the production efficiency, the quality, and the yield are improved, and it is easy to cope with the small-lot production of other products. Become.

[Brief description of drawings]

FIG. 1 is a view showing the outer appearance of a wafer prober of an embodiment of the present invention, and FIG. 2 is a view showing the structure of a probe card automatic transfer mechanism. 4 ... Test head, 6 ... Insert ring, 7 ... Card storage rack, 8 ... Probe card automatic transfer mechanism,
9 ... Probe card, 21 ... Base, 22 ... Rotation base,
23 ... Telescopic arm, 24 ... Telescopic arm drive screw, 29 ... Telescopic arm drive motor, 31 ... Probe card mounting plate, 33 ... Rotation motor, 35 ... Vertical drive screw, 36 ... Vertical Drive motor.

Claims (2)

[Claims] 1. A wafer prober for measuring a contact point of a probe card by contacting electrode pads of a plurality of semiconductor elements formed on a semiconductor wafer with a plurality of types of the probe card at predetermined positions. At the same time, the wafer prober is configured so that the probe card can be automatically exchanged via a transfer mechanism having an expandable arm that takes out the probe card according to a preset program and transfers the probe card to the insert ring. 2. The telescopic arm has a structure in which a large number of links are crossed in an X shape and the intersections and joints are connected by pivot pins. Wafer prober.