JPH11133061A - Probe card and method for testing the card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe card having no fear of damaging a protective film due to contact with a dummy needle because of easy taking of an ohmic contact, of operating a pressure of the needle at a wiring layer or the like. SOLUTION: A probe card 26 comprises a plurality of probe needles 25 to be brought into contact with a plurality of pellet regions 17 on a wafer 10, and a plurality of dummy needles 24 to be brought into contact with a scribing line 12 of a periphery of the region having an electrode pad 13 at the time of bringing the needles 24 into contact with the pad 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card, and more particularly, to a probe card for measuring electrical characteristics of a semiconductor integrated circuit formed in a plurality of pellet regions partitioned on a wafer.

[0002]

2. Description of the Related Art In general, a large-scale semiconductor integrated circuit (hereinafter, referred to as a large-scale semiconductor integrated circuit)
LSIs) are formed in a large number of pellet regions partitioned by grid-like scribe lines formed on a wafer. The electrical characteristics of the semiconductor integrated circuit formed in each pellet region are measured using an IC tester in a wafer state that is not separated as each LSI chip. During this measurement,
Since the electrode pads of semiconductor integrated circuits are extremely small, IC
A probe card is mounted on the test head of the testing machine. The probe card includes a large number of elongated probe needles that contact each electrode pad and exchange signals between the semiconductor integrated circuit and the IC tester.

In the conventional probe card, when measuring the electrical characteristics of each pellet region in which about 1000 pieces are formed per wafer, the tip of the probe needle is pressed against the wafer to make ohmic contact with the electrode pad. Therefore, the tip of the probe needle was easily worn. The service life of such a probe card is, for example, about several hundred thousand times, which is equivalent to about 500 wafers. In particular, in recent years, due to the demand for LSI miniaturization and the progress of assembly bonding technology, etc., LSI electrode pads have become
One side is reduced from about 120 μm to about 80 μm. Along with this, the outer diameter of the tip of the probe needle of the probe card is also thinned to about 50 to 30 μm, so that the wear of the probe needle 15 becomes faster and the service life of the probe card itself is almost halved. . For this reason, proposals have been made to reduce wear of the probe needle tip.

FIG. 5 is a plan view showing the probe card proposed above in use. A large number of pellet regions 17 are formed on the wafer 10 and partitioned by the grid-like scribe lines 12. The probe card 16 has a ring-shaped card body 16a, and the card body 16a is provided with a probe needle 15, dummy needles 20, 21 in an opening 16b.
, And are arranged in a predetermined order in the circumferential direction.

The probe card 16 is mounted on a test head (not shown) of an IC tester, and is fixed with the pellet region 17 to be measured positioned substantially at the center of the card body 16a. At this time, the tip of each probe needle 15 contacts a corresponding aluminum electrode pad (hereinafter simply referred to as an electrode pad) 13. The tip of each dummy needle 20 contacts the electrode pad 13 with which the adjacent probe needle 15 contacts, and the tip of the dummy needle 21 contacts the electrode pad 13.
In contact with the protective film region where no is formed. In the probe card 16, the probe needle 15 and the dummy needles 21 and 22
Is brought into contact in this manner, the load applied to the probe needle 15 is reduced, and wear of the tip is reduced.

[0006]

In the conventional probe card 16, the probe needle 15 and the dummy needle 20 are simultaneously brought into contact with the same electrode pad 13 during measurement, as described above. For this reason, when aligning the probe card 16 with the target pellet region 17, the probe needle 15 is easily detached from the electrode pad 13 due to misalignment,
There was a problem that it was difficult to make ohmic contact.
In addition, the dummy needles 21 in contact with the protective film region may damage the protective film and deteriorate the moisture resistance of the pellet region 17, or the semiconductor element may be damaged due to the pressure of the dummy needles 21 acting on the wiring layer. was there.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a probe card which is easy to make an ohmic contact, has no risk of damaging a protective film by contact with a dummy needle, or acting on a wiring layer due to the pressure of the dummy needle. With the goal.
A further object of the present invention is to provide a test method that can be suitably performed using the above-mentioned probe card.

[0008]

In order to achieve the above object, a probe card according to the present invention comprises a plurality of probe needles which contact electrode pads of a semiconductor integrated circuit formed in a plurality of pellet regions on a wafer; A plurality of dummy needles that come into contact with scribe lines around a pellet region having the electrode pads when the probe needles contact the electrode pads.

In the probe card of the present invention, at the time of measurement,
Since the probe needle can be brought into contact with the electrode pad separately from the dummy needle, it is easy to make ohmic contact. By bringing the plurality of dummy needles into contact with the scribe line of the wafer, the load applied to the probe needles can be reduced, so that the abrasion of the probe needle tips can be reduced. Further, since the dummy needle does not contact the protective film region, there is no danger of damaging the protective film by the contact of the dummy needle or damaging elements such as transistors due to the pressure on the wiring layer when the dummy needle contacts. be able to.

Here, it is preferable that a plurality of dummy needles be maintained at a common substrate potential.

More preferably, the probe needles and the dummy needles have substantially the same elasticity, and 30 or more dummy needles are provided. In this case, the supporting force to the probe needle obtained by bringing the dummy needle into contact with the scribe line is stabilized.

It is preferable that the probe needle and the dummy needle have an outer diameter of each tip of 30 μm or less. In this case, it is possible to sufficiently meet the recent demand for LSI miniaturization.

[0013] Preferably, the probe card is formed in a ring shape, and probe needles and dummy needles are arranged substantially alternately in the circumferential direction. In this case, the effect of supporting the load on the probe needle with the dummy needle can be made more effective.

According to another aspect of the present invention, there is provided a test method using the probe card, wherein an electric potential equal to a substrate supply voltage of the semiconductor integrated circuit is supplied to the dummy needle while an electric potential of the semiconductor integrated circuit is supplied to the dummy needle. The characteristic is measured.

Since the scribe line is usually at the same potential as the semiconductor substrate, according to the above-mentioned test method, the measurement can be performed without malfunction by supplying the substrate potential to the dummy needle when measuring the electrical characteristics. it can.

[0016]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a plan view showing a probe card according to an embodiment of the present invention in use. On the wafer 10, a large number of pellet regions 17 divided by scribe lines 12 formed in a lattice with a width a (for example, 50 μm).
Are formed. The probe card 26 includes a ring-shaped card main body 26a, and a plurality of probe needles 25 and dummy needles 24 extend in the card main body 26a with their distal ends substantially at the center of the opening 26b.

The probe needles 25 and the dummy needles 24 are positioned so as to be substantially alternately arranged in the circumferential direction of the card body 26a, and the rear ends thereof are fixed to the card body 26a. Each probe needle 25 has its position and position so that when the probe card 26 is set at a regular position where the pellet region 17 to be measured is located substantially at the center of the opening 26b, the corresponding electrode pad 13 properly contacts. Length is set. The position and length of each dummy needle 24 is set so that each probe needle 25 contacts the scribe line 12 around the pellet region 17 having the electrode pad 13 when the probe needle 25 contacts the electrode pad 13. ing. In the present embodiment, the probe needles 25 and the dummy needles 24 have substantially the same elasticity, and a total of 30 or more dummy needles 14 are provided. Each dummy needle 14 has a card body 26
a are electrically connected to each other.

FIG. 2 is a sectional view showing a probe needle, a dummy needle, and a pellet region at the time of measurement. Each tip of the probe needle 25 and the dummy needle 24 is bent in a hook shape, and the outer diameter c of each tip is formed to be, for example, 30 μm or less. A wafer 10 is mounted on a wafer stage 19, and a pellet region 11 on the wafer 10
The tip of the probe needle 25 is in contact with the electrode pad 13 provided in the above, and the tip of the dummy needle 24 is in contact with the scribe line 12 around the pellet region 11. Pellet area 1
The length b of one side is, for example, about 120 μm.

FIG. 3 is a schematic diagram showing a measurement system of the probe card of FIG. The probe card 26 is mounted on the LSI tester 20, and the probe needle 25 and the dummy needle 24 are electrically connected to the LSI tester 20 in a predetermined state. A plurality of dummy needles 1 connected to each other
4 is supplied from the LSI tester 20 with a potential equal to the substrate supply voltage of the semiconductor integrated circuit. Usually, the substrate potential is also supplied from one or more pins to the LSI side when measuring the electrical characteristics. That is, all the dummy needles 14 are electrically connected to, for example, one of the plurality of probe needles 25 to which the substrate potential is supplied.

When the measurement is performed using the probe card 26 having the above-described configuration, first, the probe card 26 is mounted on a test head of an IC tester (not shown), and the pellet area 17 to be measured is substantially placed on the card body 16a. The probe card 26 is fixed while being positioned at the center. When the wafer stage 19 is raised, the electrode pads 13 come into contact with the probe needles 25. When the wafer stage 19 is lowered, the electrode pads 13 are separated from the probe needles 15, and the wafer stage 19 is moved in parallel. It can be sequentially sent to the pellet area 17.

With the pellet area 17 to be measured positioned substantially at the center of the card body 16a, the wafer stage 1
When 9 is raised, probe needle 25 contacts its corresponding electrode pad 13. When measuring in this state, the LSI tester 2 is connected to the dummy needles 14 that are electrically connected to each other.
Substrate potential is supplied from 0, and pellet region 1
Signals are exchanged between the semiconductor integrated circuit 1 and the LSI tester 20. Since the scribe line 12 has the same potential as the semiconductor substrate, the measurement is performed without malfunction by supplying the substrate potential to the dummy needle 24.

In the above measurement, the probe needle 25 can be brought into contact with the electrode pad 13 separately from the dummy needle, so that an ohmic contact can be easily made. Further, the load applied to the probe needles 25 can be reduced by bringing the plurality of dummy needles 24 into contact with the scribe lines 12 of the wafer 10, so that the probe needles 2
Wear of the tip of No. 5 can be reduced. FIG. 4 is a graph showing a correlation between the number of dummy needles and the number of times the probe card can be used. When the dummy needles 24 are not provided at all, the service life of the probe card is about 2 to 3000 times, but when the dummy needles 24 become about 30 pieces, the service life of the probe card becomes 50,000 times. Get closer. This is a result in the case where the elasticity of the dummy needle 24 and the probe needle 25 is substantially the same. For example, when the dummy needle 24 having elasticity greater than the probe needle 25 is used, less than 30 needles are provided. It becomes possible.

The scribe line 12 is connected to the wafer 10
Since the dummy needles 25 are distributed over a wide area in a lattice
The degree of freedom of arrangement is high, and the number can be easily increased. Further, since the dummy needle 25 does not contact the protective film region, the protective film is damaged by the contact of the dummy needle 25, or an element such as a transistor is damaged by the pressure on the wiring layer when the dummy needle 25 contacts. There is no fear.

Although the present invention has been described based on the preferred embodiment, the probe card of the present invention and the test method using the probe card are not limited to the above embodiment. Probe cards with various modifications and changes from the above embodiment and test methods using the probe cards are also included in the scope of the present invention.

[0025]

As described above, according to the probe card of the present invention, the ohmic contact is easily made, the protective film is damaged by the contact of the dummy needle, or the pressure by the dummy needle acts on the wiring layer. Can be eliminated. Further, since the substrate potential is usually supplied to the dummy needle that contacts the scribe line having the same potential as the semiconductor substrate, the test method according to the present invention can perform the measurement without malfunction.

[Brief description of the drawings]

FIG. 1 is a plan view showing a use state of a probe card according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a probe needle, a dummy needle, and a pellet region during measurement.

FIG. 3 is a schematic diagram showing a measurement system of the probe card of FIG.

FIG. 4 is a graph showing a correlation between the number of dummy needles and the number of times the probe card can be used.

FIG. 5 is a plan view showing a conventional probe card in use.

[Explanation of symbols]

 Reference Signs List 10 wafer 12 scribe line 13 electrode pad 17 pellet area 24 dummy needle 25 probe needle 26 probe card

Claims (6)

[Claims] 1. A plurality of probe needles contacting an electrode pad of a semiconductor integrated circuit formed in a plurality of pellet regions on a wafer, and a periphery of the pellet region having the electrode pad when the probe needle contacts the electrode pad. And a plurality of dummy needles contacting the scribe line. 2. The probe card according to claim 1, wherein said plurality of dummy needles are electrically connected to each other. 3. The probe card according to claim 1, wherein the probe needles and the dummy needles have substantially the same elasticity, and 30 or more dummy needles are provided. 4. The probe card according to claim 1, wherein each of the probe needle and the dummy needle has an outer diameter of 30 μm or less at each tip. 5. The probe card according to claim 1, wherein the probe needle and the dummy needle are formed in a ring shape, and the probe needles and the dummy needles are arranged substantially alternately in a circumferential direction. 6. A test method using the probe card according to claim 1, wherein an electric characteristic of the semiconductor integrated circuit is measured while supplying a potential equal to a substrate supply voltage of the semiconductor integrated circuit to the dummy needle. A test method using a probe card.