JPH01182756A - Probe card - Google Patents

Abstract

PURPOSE:To enable detecting the presence of a wafer correctly, by covering a contact-point with non-oxidizing compound metal in order to prevent oxidation. CONSTITUTION:A first probe 11 and a second probe 14 are formed with tungsten. The vicinity of contact points 13 of the probes 11 and 14 is plated with metal in order to prevent oxidation. Gold, platinum, silver and the like are used for plating. An insulating material 12' is formed at the tip part of the probe 11, which is the contact point to a body to be measured. Thus the flow of a current, which is conducted through the probe 11, into the body to be measured, i.e., a material under measurement, is prevented. Therefore, erroneous current does not flow through the body to be measured when the body is measured. Erroneous measurement can be avoided. Thus the efficient measurement can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a probe card for measuring the electrical characteristics of an object to be measured in the manufacturing process of a semiconductor integrated circuit element (IC).

[Prior art and problems to be solved by the invention] When measuring a wafer, which is an assembly of ICs, which is an object to be measured using a prober, each bonding pad of each IC chip is electrically connected to the prober body. The electrical and electrical characteristics of the IC are sequentially measured by contacting a large number of implanted probe needles. For measurement, the mounting table on which the wafer is placed is raised, and an edge sensor with an open/open circuit is used to detect contact between the IC chip's bonding pad and the probe needle; at this time, the edge sensor becomes an open circuit. . When the measurement of one or more ICs is completed, the mounting table is lowered and the probe needle leaves the object to be measured. At the same time, the edge sensor becomes a closed circuit to notify this state. The mounting table is moved so that the probe needle contacts the next IC chip, and is raised again to bring the bonding pad into contact with the probe needle, thereby continuously measuring the IC chips.

The measurement of one wafer is now completed.

In such electrical and electrical characteristic testing where continuous measurements are performed, the mounting table is raised and lowered each time the measurement of each IC is started and completed. In order to detect this operating state, the edge sensor is shaped like a plow.The edge sensor shown in Figure 3 has a tip 2 bent vertically, a needle 1 that contacts the wafer, and a portion just before the needle 1 bends vertically. It consists of a needle 4 with a tip 5 bent in the horizontal direction so as to make contact at 3. (Other probe needles and edge sensors are omitted.) The first needle 1 and the second needle 4 are constantly connected to a current. The wafer 6 is lifted and the tip 2' of the first needle 1 comes into contact with the wafer 6, and when the wafer 6 is lifted a little further, the first needle 1 also rises slightly. However, the contact point 3 with the second needle 4 becomes a switch, becomes non-contact, and becomes an open circuit, thereby detecting the presence of the wafer.IC
When the measurement is completed, the mounting table on which the wafer is placed is lowered, the probe needle leaves the IC, and the contacts 3 of the edge sensor come into contact, forming a closed circuit. The prober reads this status and displays it. In this way, I
It is used to detect the presence or absence of C and the state in which the probe needle repeatedly contacts and separates from the IC.

Here, current is constantly flowing through the two-needle contacts of the edge sensor, making them susceptible to oxidation. When the surface is oxidized, the contact resistance increases, resulting in poor contact, which impairs the function of the edge sensor, resulting in a disadvantage that the IC's retention capacity decreases or becomes unmeasurable.

Therefore, one object of the present invention is to provide an edge sensor that eliminates the above-mentioned drawbacks, maintains a good contact state at the contacts, and functions as a good switch.

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the present invention provides a probe needle whose tip is brought into contact with an electrode of the object to be measured to measure the electrical characteristics of the object to be measured, and the wafer. In a probe card equipped with an edge sensor that detects the position of the object, the edge sensor includes at least two needles having one contact and forming a closed circuit, and when the probe needle is not in contact with the electrode of the object to be measured, , the at least two needles are in contact and electrically conductive, and when the probe needle contacts the electrode of the chip, the first needle of the at least two needles is raised and the second needle is raised. The point of contact with the needle separates, resulting in an open circuit,
The contact portion is coated with a non-oxidizing compound metal to prevent oxidation.

[Example] Hereinafter, the present invention will be explained by giving examples.

In the edge sensor shown in FIG. 1, the first needle 11 has a tip 12 bent vertically, an insulator 12'' is glued to the tip, and the contact point 13 is made to contact the lower part of the first needle 11. A second needle 1 whose tip portion 15 is bent horizontally
4 is formed, and when the chip is measured, it is connected to an electric circuit different from the measurement circuit and is in a conductive state.

These needles must be hard so that they can withstand repeated contact tests, and are made of hard metal such as tungsten. The first needle 11 and the second needle 14 are made of tungsten, and the contact point 1 of the first needle 11 and the second needle 14 is
The area around 3 is plated with metal to prevent oxidation. The metals used for plating are hard and have good conductivity, such as gold, platinum,
Silver, rhodium, etc. are applied. Gold, platinum, and rhodium are suitable because they are chemically stable and extremely hard, but silver plating discolors due to oxides and sulfides, so it is preferable to perform rhodium plating or chromate treatment on the silver plating to prevent this. It is. These metal-plated contacts are resistant to oxidation due to high temperatures and contact, and due to oxidation,
The contact resistance of tungsten increases, and it is possible to prevent the switch from becoming defective due to poor contact.

In addition, an insulator 12'' is formed at the tip of the first needle 11, which is the part that contacts the object to be measured, to prevent the current conducted through the first needle 11 from flowing to the object to be measured, which is the object to be measured. To prevent.

Therefore, when measuring the object to be measured, an erroneous current will not flow to the object to be measured and erroneous measurements will not be made, and efficient measurement can be performed.

The insulator 12'' may be an insulating material made of plastic, glass, or other material. However, depending on the edge sensor, this insulator may not be necessary.

Another embodiment of the edge sensor is shown in FIG.

In FIG. 2, an ordinary probe needle 26 is provided with an insulating part 27, and a first needle 24 is formed by bending the tip part 25 in the horizontal direction so as to contact the insulating part 27. A second needle 21 that makes contact with a contact point 23 is formed to form an edge sensor.

The first needle 24 and the second needle 21 have a contact point 23 and are electrically connected. The probe needle 26 is also used for normal IC measurements, but when it comes into contact with the rising wafer and is pushed up, the probe needle 26 pushes up the first needle 24 on the insulating part 27, thereby making contact with the second needle 21. 23 becomes a non-contact state and can be used as a needle to detect the presence of a wafer.

The first needle 24 and the second needle 21 are always electrically connected,
Since the insulating portion 27 is provided at the contact point with the probe needle 26, the wafer measurement circuit and the wafer detection sensor circuit can be kept in an insulated state. First needle 24 and second needle 2
The contact portion 23 with 1 is plated with gold, platinum, silver, or rhodium to prevent oxidation.

[Effects of the Invention] As explained above, in the edge sensor of the present invention, since the contacts of at least two needles are plated with metal, poor contact between the contacts can be avoided and the presence of a wafer can be correctly detected. Therefore, measurement can be carried out efficiently without causing any erroneous operation of the prober. In addition, since the current flowing through the edge sensor is provided with an insulating section, it can be prevented from flowing as miscellaneous current to the chip, which is the object to be measured.
Accurate measurement results can be obtained.

[Brief explanation of the drawing]

1 and 2 are diagrams showing an embodiment of an edge sensor according to the present invention, and FIG. 3 is a diagram showing a conventional edge sensor. 1.11.24...First needle 4.14.21...Second needle 3.13.23...Contact 12'... ...Insulator 27...
・・・・・・・・・・・・Insulation part 611@・e・Φ・
・■・Φ・・・e-wafer agent Patent attorney Moritani -O Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a probe card comprising a probe needle whose tip contacts an electrode of the object to be measured and measures the electrical characteristics of the object to be measured, and an edge sensor that detects the position of the object to be measured, the edge sensor has one contact point. When the probe needle is not in contact with the electrode of the object to be measured, the at least two needles are in contact and conductive; When contacting the electrode of the chip, the first needle of the at least two needles is lifted, and the point of contact with the second needle is separated, resulting in an open circuit, and the contact portion is oxidized. A probe card characterized by being coated with a non-oxidizing compound metal for prevention.