JP2873411B2 - Probe device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe device for measuring an electrical characteristic of a device under test by bringing a probe of a probe card into contact with an electrode pad of the device under test such as a semiconductor wafer.

[0002]

2. Description of the Related Art FIG. 5 shows a known probe apparatus for inspecting electrical characteristics of a large number of IC chips formed on a semiconductor wafer (hereinafter simply referred to as a wafer). The wafer a is placed on a wafer chuck b for holding the wafer a by suction, and a probe card c is installed above the wafer a. On the lower surface of the probe card c, a stylus d that is in contact with the electrode pad of the IC chip on the wafer a is implanted. Further, as shown in FIG.
, And is provided so as to be able to turn over the probe card c. When inspecting the electrical characteristics of the wafer a, the test head e is moved to the upper part of the probe card c, and the test head e and the probe card c are electrically connected via pins or the like.

[0003]

By the way, in this type of probe device, the test head e has a multi-pin structure as the IC chip becomes finer and more complicated, and is large and heavy. . For this reason, when the test head e is installed on the upper part of the probe device as in the related art, it is necessary to make the supporting structure robust, and the increase in size and weight of the probe device is unavoidable.

[0004] Further, since the wafer a held upward is contacted with the stylus d of the probe card c above the wafer a for inspection, the oxide film dust scraped off from the surface of the electrode pad by the stylus d is inspected. There is a problem that fine dust or the like that enters from outside the probe device easily adheres to the wafer a, and the quality of the wafer a is deteriorated.

In order to solve the above-mentioned problem, the present inventors have proposed a conventional method in which a wafer is held downward, a probe card is provided with a stylus upward under the wafer, and a test head is further provided below the probe card. An inverted probe device with an inverted vertical relationship with the probe device was created.

However, when this new inverted type probe apparatus is adopted, the following new problem occurs. That is, as described above, the test head has a multi-pin structure, and the built-in electronics of the test head, mainly the driver sensor card of the tester and the pin electronics generate much heat. The heat generated from the test head, particularly convection, may cause the probe card located above the test head to become hot. Also, in general,
It is desirable that the probe card, the wafer, and the like be kept at a constant temperature.

The present invention has been made in view of the above circumstances, and has been made to reduce the size of the apparatus, prevent dust from adhering to an object to be inspected, and take measures against heat, such as removing the influence of heat generated from the test head. It is an object of the present invention to provide a probe device.

[0008]

In order to achieve the above object, the present invention provides a tester in which a stylus of a probe card is brought into contact with an electrode pad of a device under test and connected to the probe card via a test head. A probe device for measuring the electrical characteristics of the object to be inspected, provided with the stylus of the probe card facing upward above the test head,
Along with holding the object to be inspected above the probe card by holding means such that its electrode pads face downward,
A down flow of the cooling gas flowing down the test object, the probe card and the test head is formed.

In the present invention, as the holding means, for example, a mounting table capable of vacuum suction may be used.
It is preferable to have a structure movable in the X, Y, and Z directions. Examples of the cooling gas include clean air cooled by an air conditioner or the like and low-temperature N2 gas. Further, in order to form a downflow of the cooling gas, for example, an outlet for the cooling gas may be provided on the holding means side, and a fan for suction and exhaust may be provided below the test head.

[0010]

The electrical characteristics of the device under test are measured by bringing the probe of the probe into contact with the electrode pad of the device under test.
The test head generates heat, and the probe card and the like above the test head are exposed to thermal influence mainly by thermal convection.
However, according to the present invention, since a downflow of the cooling gas flowing down the test head from the test object via the probe card is formed, the problem due to the heat generation of the test head can be eliminated. In addition, by this downflow, the intrusion of dust and the like from the outside to adhere to the wafer or the like is suppressed, and the probe device is maintained in a clean state. Further, by controlling the flow rate and temperature of the downflow of the cooling gas, it is possible to keep the temperature of the object to be inspected, for example, a wafer or the like, constant.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In FIG. 1 and FIG. 2 which is a plan view thereof,
Reference numeral 1 denotes an apparatus main body casing of the probe device. The probe device includes an inspection section 3 for inspecting electrical characteristics of a large number of IC chips formed on a wafer 2 to be inspected, and an inspection section 3.
And a transfer unit 4 for transferring the wafer 2. In the inspection unit 3, a chuck 5 for vacuum-holding with the IC chip forming surface of the wafer 2 facing downward and electrode pads of each IC chip of the wafer 2 held by the chuck 5 are provided. And a probe card 7 having a stylus 6.

The probe card 7 is, as shown in FIG.
It is installed on a plate 8 of the apparatus main body casing 1 via an insert ring 9. Each stylus 6 is connected to the wiring 1
0, etc., the performance board 1 of the test head 11
2 are connected. On the other hand, the chuck 5 is provided on the X stage 14 below the Y stage 13 as shown in FIG.
It is movable in the Y direction. Further, the chuck 5 has X
The stage 14 has a structure capable of moving in the vertical direction (Z direction) and rotating.

As shown in FIG. 3 or FIG.
A supply nozzle 15 for supplying air A cooled by an air conditioner or the like (not shown) and cleaned by a filter is provided on a side of the X stage 14. The supply nozzle 15 is provided downward on the probe card 7 side. Further, a fan 16 for sucking the cooling air A and forming a downflow of the air A is provided at the bottom of the test head 11. A caster 17 is attached to the test head 11 so that the test head 11 can move on the floor 18. Further, as shown in FIG.
9 is connected to the tester 20.

An alignment bridge 21 is provided on the side of the inspection section 3.
Reference numeral 1 denotes a T for detecting the position of the IC chip on the wafer 2 and detecting the trace of the stylus 6 on the dummy wafer.
Distance (height) in the Z direction from V camera 22 to wafer 2
And a capacitance sensor 23 for detecting the On the other hand, the X stage 14 is provided with a TV camera 24 for detecting the position of the stylus 6 of the probe card 7 as shown in FIG. Capacity sensor 23 and TV camera 2
A target member 25 for correcting a deviation of the reference position of the detection system 4 is attached. The target member 25 is a small piece of glass, and a chrome cross mark 26 serving as a reference point of the TV cameras 22 and 24 is provided on the lower surface thereof.
And a conductive transparent thin film is applied so that the capacitance sensor 23 can detect the position in the Z direction.

Next, the operation of this embodiment will be described. First, the test head 11 with the casters 17 is moved on the floor 18 and set on the inspection unit 3, and the electrical connection between the performance hood 12 and the probe card 7 is established.
Although the test head 11 and the tester 20 are connected by a cable 19, the test head 11 is moved on a floor 18 by a caster 17.
The risk of disconnection or poor contact of the cable 19 due to bending of the cable 7 or dragging over a long distance can be greatly reduced as compared with the related art.

Next, the X and Y stages 14 and 13 and the chuck 5 are driven so that the electrode pads of each IC chip of the wafer 2 aligned with the chuck 5 are brought into contact with the stylus 6 of the probe card 7 and the tester 20. The electrical characteristics are inspected by: In this inspection step, while the cooled air A is supplied from the supply nozzle 15, the test
The bottom fan 16 is rotationally driven. The air A blown from the supply nozzle 15 flows down the wafer 2, the probe card 7, and the performance board 12, passes through the through hole (not shown) formed in the upper plate surface of the test head 11, and enters the test head 11. It flows in and is discharged from the bottom of the test head 11 by the fan 16.

When the test head 11 is driven, a large amount of heat is generated from the pin electronics of the test head 11 and the like. Not receive. Further, since the downflow of the air A is formed, intrusion of dust and the like from the outside of the apparatus main body casing 1 can be prevented, and the periphery of the wafer 2 can be kept clean. Further, since the probe card 7 is located below the wafer 2, dust such as an oxide film scraped off by the stylus 6 does not adhere to the wafer 2. Further, by controlling the flow rate and temperature of the air A, the temperature of the space around the chuck 5 and the probe card 7 can be kept constant.

Electrode pads on wafer 2 and probe card 7
In order to make contact with the stylus 6, accurate positioning is required, but the TV cameras 22, 24 and the capacitance sensor 23 of the position detection system may have their reference points shifted due to temperature or other causes. There is. Therefore, the reference point of the detection system is corrected using the target member 25. That is, the cross mark 26 of the target member 25 is
Is detected, and the reference points of the X and Y coordinates are corrected. Further, the distance in the Z direction to the turret member 25 is determined by the capacitance sensor 23, and the cross mark 2 is determined by the TV camera 24.
The distance in the Z direction up to 6 is obtained, and the reference point of the Z coordinate of the detection system is corrected from these detected values. The distance in the Z direction between the TV camera 24 and the cross mark 26 is detected based on the focusing of the high- and low-magnification cameras of the TV camera 24.

In the above embodiment, the test head 1
1 has a caster 17 and a structure capable of moving on the floor portion 18. However, such a structure is not necessarily required. For example, the test head 11 is slidably mounted via a guide rail. Is also good.

[0020]

As apparent from the above description, according to the present invention, since the test head is an inverted type in which the test head is arranged below the probe device, the support mechanism and the moving mechanism of the test head can be simplified. The size and weight of the probe device can be reduced. Since the down flow of the cooling gas flowing down the test head via the test object and the probe card is formed, it is possible to eliminate adverse effects such as deformation of the probe card due to heat generated by the tester head. Further, by forming the downflow of the cooling gas, it is possible to suppress the entry of fine dust and the like from the outside of the probe device, and it is possible to reduce the quality deterioration due to the adhesion of dust to the inspection object. Further, by controlling the flow rate and temperature of the downflow of the cooling gas, the temperature around the object to be inspected or the like can be kept constant, and the accuracy and reliability of the inspection by the probe device can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view showing one embodiment of a probe device according to the present invention.

FIG. 2 is a partially broken plan view of FIG.

FIG. 3 is an enlarged front sectional view of a main part of FIG. 1;

FIG. 4 is an enlarged perspective view of a mechanism for moving a chuck portion of the wafer of FIG. 1;

FIG. 5 is a schematic configuration diagram of a conventional probe device.

[Explanation of symbols]

 2 Wafer (inspection object) 5 Chuck (holding means) 6 Contact probe 7 Probe card 11 Test head 15 Supply nozzle 16 Fan A Cooled air

Claims (1)

(57) [Claims] 1. A probe device in which a stylus of a probe card is brought into contact with an electrode pad of a device under test and an electrical characteristic of the device under test is measured by a tester connected to the probe card via a test head. The probe of the probe card is provided above the head with the stylus facing upward, and the test object is held above the probe card by holding means so that its electrode pad faces downward. And a down flow of a cooling gas flowing down the test head.