JP5048942B2 - Probe pin, probe card and probe device - Google Patents

Description

  The present invention relates to a probe pin, a probe card, and a probe device for contacting an object to be inspected and inspecting electrical characteristics of the object to be inspected.

  For example, inspection of electrical characteristics of electronic circuits such as ICs and LSIs formed on a semiconductor wafer is performed by pressing probe pins provided on the probe device against and contacting the electrodes of the electronic circuit on the wafer side. Yes.

  Since the above-mentioned probe pin needs to scrape the oxide film on the electrode surface, conventionally, a strong metal such as tungsten or nickel has been used as the material of the probe pin so that it can withstand many inspections. (See Patent Document 1).

JP 2005-106497 A

  However, in the inspection of electrical characteristics, when the probe pin contact portion is pulled away from the wafer side electrode, a part of the wafer side electrode may peel off and adhere to the probe pin contact portion. For this reason, there are concerns that deposits may accumulate on the contact portion of the probe pin due to a large number of inspections, resulting in poor electrical contact between the probe pin and the electrode. For this reason, it was necessary to replace the probe pin in a short period of time, and to remove the accumulated deposits with a brush, which shortened the life of the probe pin.

  By the way, in recent years, in order to reduce the contact pressure between the probe pin and the electrode, a voltage is applied to the probe pin in contact with the electrode, and the oxide film on the surface of the electrode is broken down by utilizing the fritting phenomenon. Techniques for achieving conduction with electrodes have been proposed. In this case, it has been confirmed that a relatively strong adhesive force is generated by welding between the probe pin and the electrode. When the probe pin and the electrode are pulled apart, a part of the electrode breaks due to the tensile stress at that time. It is easily damaged and sticks to the contact area of the probe pin. Therefore, particularly when the fritting technique is used, deposits accumulate on the probe pin, and contact failure between the probe pin and the electrode tends to occur.

  The present invention has been made in view of the above points, and an object of the present invention is to prevent a part of a contact portion on the inspection object side such as a wafer from peeling off and adhering to a contact portion of a probe pin. .

A reference example for achieving the above object is a probe pin for contacting an object to be inspected to inspect the electrical characteristics of the object to be inspected, and at least the surface of the contact portion in contact with the object to be inspected is It is characterized in that it is made of a material whose strength is weaker than the contact part on the side of the inspection object. A material with low strength means a material that breaks with a small stress.

According to this reference example , the surface of the contact portion of the probe pin is weaker than the contact portion on the inspection object side. Peel off. In such a case, no deposits are deposited on the probe pin, and a new surface of the probe pin is always exposed, so that stable contact with the object to be inspected can be maintained even if the probe pin is used many times. As a result, for example, the cleaning work of the probe pin becomes unnecessary, and the life of the probe pin can be extended.

  The surface of the contact portion may be formed of a material having a low strength, and the inner portion of the surface of the contact portion may be formed of a material having a stronger strength than the contact portion on the inspection object side.

  The weak material of the contact portion may be tin or an alloy containing tin.

  The probe pin may be used when the probe pin is electrically connected to the contact portion on the inspection object side using a fritting phenomenon.

According to a reference example from another viewpoint, a probe card provided with the probe pins described in the above reference example is provided.

  According to another aspect of the present invention, there is provided a probe apparatus including a probe pin for contacting an object to be inspected and inspecting an electrical characteristic of the object to be inspected, which is more than a contact part on the object side to be in contact with the probe pin A container for storing a melt of a material having low strength, and a moving mechanism for moving the container so that the contact portion of the probe pin that contacts the object to be inspected can be immersed in the melt in the container. , At least the surface of the contact portion of the probe pin is formed of a material whose strength is weaker than that of the contact portion on the inspection object side.

  According to the present invention, since the surface of the contact portion of the probe pin is weaker than the contact portion on the inspection object side, when the bonded probe pin and the inspection object are separated, the contact portion side of the probe pin is broken and peeled off. To do. Therefore, no deposits are deposited on the probe pin, and the new surface of the probe pin is exposed, so that stable contact with the object to be inspected can be maintained even if the probe pin is used many times. As a result, for example, the cleaning work of the probe pin becomes unnecessary, and the life of the probe pin can be extended. Further, since the contact portion of the probe pin can be immersed in the melt of the container, the peeled portion of the contact portion can be supplemented and recovered. As a result, the lifetime of the probe pin can be further extended. Moreover, since the surface shape of the contact portion of the probe pin is stabilized, the contact with the object to be inspected is further stabilized.

  The probe device may include a heating member that heats the container.

  The probe device may have a fritting function that electrically connects the object to be inspected and the probe pin using a fritting phenomenon.

  According to the present invention, it is not necessary to clean the probe pin, and the life of the probe pin can be extended. In addition, since stable contact points with low electrical resistance can be formed, the inspection accuracy of electrical characteristics can be stabilized.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is an explanatory diagram showing an outline of the configuration of the probe apparatus 1 according to the present embodiment.

  For example, the probe apparatus 1 includes a probe card 2, a mounting table 3 on which a wafer W as an object to be inspected is mounted, and a moving mechanism 4 that moves the mounting table 3.

  The probe card 2 includes, for example, a contactor 11 that supports a plurality of probe pins 10 that contact the electrodes of the wafer W on the lower surface, and a printed wiring board 12 that transmits and receives electrical signals to the probe pins 10 through the main body of the contactor 11. . The contactor 11 and the printed wiring board 12 are formed, for example, in a substantially disk shape, and the printed wiring board 12 is arranged on the upper surface side of the contactor 11 so as to be able to energize the contactor 11.

  The probe pin 10 is joined to a connection terminal 20 formed on the lower surface of the main body of the contactor 11, for example. For example, as shown in FIG. 2, the probe pin 10 includes a linear beam portion 30 and a contact portion 31 protruding in a direction perpendicular to the tip portion of the beam portion 30, and has a substantially L shape. The rear end side of the beam portion 30 is joined to the connection terminal 20, and the contact portion 31 protrudes downward at the tip end of the beam portion 30. The contact portion 31 contacts the electrode P as a contact portion of the wafer W.

  The probe pin 10 is integrally molded, for example, and is entirely formed of an electrode P of the wafer W, for example, a conductive material having a lower strength than aluminum, for example, tin. As the material of the probe pin 10, for example, a material having a tensile strength smaller than that of the electrode P by 10 MPa or more is selected.

  Inside the main body of the contactor 11, connection wirings (not shown) for electrically connecting the probe pins 10 on the lower surface side and the printed circuit board 12 on the upper surface side are formed.

For example, as shown in FIG. 3, the probe pin 10 applies a voltage to a test circuit 40 that transmits and receives electrical signals for testing electrical characteristics, and to a pair of probe pins 10 in order to cause a fritting phenomenon. The fritting circuit 41 is connected via a switching circuit 42 that switches between the test circuit 40 and the fritting circuit 41. Here, the fritting phenomenon is that when the potential gradient applied to the surface of the electrode P becomes about 10 ⁵ to 10 ⁶ V / cm, the oxide film on the surface of the electrode P is broken down, and a current flows through the oxide film. A phenomenon. The fritting circuit 41 applies a predetermined voltage between a pair of probe pins 10 in contact with the electrode P of the wafer W to increase the potential gradient between the two probe pins 10, thereby At the two contact portions between the probe pin 10 and the electrode P, the oxide film on the surface of the electrode P can be broken down at the same time to electrically connect the electrode P and the probe pin 10. In the present embodiment, the fritting function is realized by the fritting circuit 41.

  As shown in FIG. 1, the moving mechanism 4 includes, for example, a horizontal support base 50 that supports the mounting table 3 from below, a lift drive unit 51 such as a cylinder that lifts and lowers the horizontal support base 50, and a lift drive unit 51 in the horizontal direction. The XY stage 52 is moved in two directions, the X direction and the Y direction. Thereby, the wafer W mounted on the mounting table 3 can be moved three-dimensionally and the probe pin 10 can be brought into contact with a desired electrode P of the wafer W.

  For example, next to the mounting table 3 on the horizontal support table 50, a heating plate 61 is provided as a heating member in which a heater 60 that generates heat by power feeding is incorporated. On the hot plate 61, as shown in FIG. 4, a container 62 for storing molten tin A which is a constituent material of the probe pin 10 is provided. The molten tin A in the container 62 can maintain a molten state by the heat of the hot plate 61. Further, since the container 62 is mounted on the same horizontal support base 50 as the mounting table 3, it can be moved three-dimensionally by the moving mechanism 4, and the contact portion 31 of the probe pin 10 is connected to the molten tin A in the container 62. Can be dipped. Thereby, tin can be adhered to the contact portion 31 of the probe pin 10.

  Next, the operation of the above-described probe apparatus 1 will be described together with the wafer W inspection process. First, the wafer W is mounted on the mounting table 3. Next, the wafer W is three-dimensionally moved by the moving mechanism 4, and the two probe pins 10 are brought into contact with each electrode P of the wafer W as shown in FIG. At this time, the electrode P and the probe pin 10 are contacted with an extremely low contact pressure. Next, a voltage is applied between the two probe pins 10 of each electrode P using the fritting circuit 41. By gradually increasing this voltage and increasing the potential gradient between the probe pins 10, a fritting phenomenon occurs, and the oxide film on the surface of the electrode P is dielectrically broken (fritting process). Thus, the electrical resistance between the probe pin 10 and the electrode P is reduced, and the probe pin 10 and the electrode P are electrically connected.

  After all the electrodes P and the probe pins 10 are electrically connected, the switching circuit 42 switches the fritting circuit 41 to the test circuit 40. Subsequently, an electrical signal is sent from each probe pin 10 to the electrode P using the test circuit 40, and the electrical characteristics of the electronic elements on the wafer W are inspected.

  When the inspection of the electrical characteristics is completed, the wafer W is lowered by the moving mechanism 4 and the probe pin 10 is separated from the electrode P. When the fritting process described above is performed, the adhesive force between the probe pin 10 and the electrode P is increased. This is considered to be because a high current temporarily flows in a narrow contact region between the probe pin 10 and the electrode P during the fritting process, and the probe pin 10 and the electrode P are welded. When the probe pin 10 is pulled away from the electrode P, tensile stress acts on the probe pin 10 and the electrode P. Since the strength of the probe pin 10 is weaker than that of the electrode P, the probe pin 10 is in contact with the probe pin 10 and the electrode P as shown in FIG. When the electrode P is pulled apart, a part of the surface of the contact portion 31 of the probe pin 10 is broken and peeled off and adheres to the electrode P.

  Thereafter, the wafer W is unloaded from the probe apparatus 1. Then, after the above-described inspection process is repeated a predetermined number of times, the container 62 is horizontally moved to the lower side of the probe pin 10 by the moving mechanism 4 as necessary, and then lifted, as shown in FIG. The contact portion 31 of the pin 10 is immersed in the molten tin A in the container 62. In this way, tin is replenished to the missing portion of the contact portion 31 of the probe pin 10, and the surface shape of the probe pin 10 is recovered.

  According to the above embodiment, since the probe pin 10 is made of tin that is weaker than the electrode P of the wafer W, when the probe pin 10 and the electrode P are pulled apart, the probe pin 10 side is broken and peeled off. To do. As a result, a part of the electrode P does not adhere and accumulate on the probe pin 10 side, and a new surface of the probe pin 10 is exposed. Therefore, even if the probe pin 10 is used many times, the probe pin 10 and the electrode P Can maintain contact with. Therefore, the lifetime of the probe pin 10 can be extended. In addition, since no deposits are deposited on the probe pin 10, the contact of the probe pin 10 with the electrode P can be stabilized.

  In the above embodiment, since the electrical connection between the probe pin 10 and the electrode P is achieved using the fritting phenomenon, it is considered that welding has occurred between the probe pin 10 and the electrode P. For this reason, a relatively large force is required when pulling apart. Therefore, forming the probe pin 10 used for the fritting process with a material having a lower strength than the electrode P and urging the probe pin 10 to rupture means that a part of the electrode P adheres to the probe pin 10. It is very effective in preventing.

  In the above embodiment, since the container 62 in which the molten tin A is stored is provided in the probe device 1, the probe pin 10 is immersed in the molten tin A in the container 62 to replenish the defective portion of the probe pin 10. be able to. Thereby, since the shape of the probe pin 10 is maintained, the lifetime of the probe pin 10 can be further extended.

  Since the container 62 is mounted on the hot plate 61, the molten tin A in the container 62 can be maintained in a molten state.

In the above embodiment, the entire probe pin 10 is formed of tin. However, only the surface of the contact portion 31 of the probe pin 10 is formed of tin that is weaker than the electrode P, and the surface of the contact portion 31 is formed. The inner portion may be made of a material stronger than the electrode P, such as nickel or tungsten. For example, as shown in FIG. 7, the main body 10a of the probe pin 10 is made of nickel (Ni), and the surface 10b of the contact portion 31 of the probe pin 10 is coated with tin. The tin on the surface 10b is coated to a thickness of about 10 ^{−4 to} 0.01 mm, for example. According to this example, since the main body 10a of the probe pin 10 is formed of a material having high strength, the strength of the entire probe pin 10 is ensured, and for example, the probe pin 10 is not deformed by contact with the electrode P. Moreover, since only the surface of the contact portion 31 is coated with tin, the chipping at the time of separation is performed only on the surface of the contact portion 31, so that a large tin lump does not adhere to the electrode P side. Note that the entire main body 10a (the beam portion 30 and the contact portion 31) of the probe pin 10 may be formed of the above-described strong material, or only the contact portion 31 may be formed of a strong material. .

  The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the spirit described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs. For example, in the above embodiment, tin is used as a material having a strength lower than that of the electrode P. However, other materials such as an alloy containing tin and solder may be used. In the above embodiment, the present invention is applied to the probe pin used when the fritting process is performed. However, the present invention can also be applied to the probe pin used for the inspection in which the fritting process is not performed. . The present invention can also be applied to the case where the object to be inspected is another substrate such as an FPD (flat panel display) other than the wafer W, a mask reticle for a photomask, or the like.

  Experiments were performed on the life of the probe pin when the material of the probe pin 10 is tin, which is weaker than the electrode P, and when the material of the probe pin is tungsten. The material of the electrode P at this time is aluminum. In FIG. 8, the horizontal axis indicates the number of measurements, and the vertical axis indicates the contact resistance. If the contact resistance is high, the probe pin cannot be used and the life of the probe pin will be extended. As shown in FIG. 8, the probe pin 10 using tin (Sn) has a stable contact resistance of about 1Ω even when the number of measurements is 300 times. With respect to probe pins using tungsten (W), the number of measurement is about 50 times, the measurement points where the contact resistance value varies greatly, and the contact resistance value is also large. From this experimental result, it can be confirmed that the life of the probe pin is prolonged by making the material of the probe pin 10 tin. In addition, it can be confirmed that the contact between the probe pin and the electrode is more stable because the contact resistance is stable at a low value when tin is used for the probe pin.

  The present invention is useful in extending the life of the probe pin.

It is a side view which shows the outline of a structure of a probe apparatus. It is explanatory drawing of the longitudinal cross-section which shows the structure of the attachment part of a probe pin. It is explanatory drawing which shows the function of the circuit of a printed wiring board. It is explanatory drawing of the longitudinal cross-section of a container and a hot platen. It is explanatory drawing which shows the state which two probe pins contacted the electrode. (A) is explanatory drawing of the longitudinal cross-section which shows the state which contacted the probe pin to the electrode. (b) is explanatory drawing of the longitudinal cross-section which shows the state which pulled the probe pin away from the electrode. It is explanatory drawing of the longitudinal cross-section of the contact part which coat | covered the surface with tin. It is a graph which shows the experimental result which measures the lifetime of a probe pin.

Explanation of symbols

1 Probe Device 10 Probe Pin 31 Contact Part P Electrode W Wafer

Claims (3)

A probe device having a probe pin for contacting an object to be inspected to inspect the electrical characteristics of the object to be inspected,
  A container for storing a melt of a material whose strength is weaker than the contact portion on the inspected object side that contacts the probe pin;
  A moving mechanism for moving the container so that the contact portion of the probe pin that contacts the object to be inspected can be immersed in the melt in the container,
  At least the surface of the contact portion of the probe pin is formed of a material whose strength is weaker than that of the contact portion on the inspection object side. The probe apparatus according to claim 1, further comprising a heating member that heats the container. The probe apparatus according to claim 1, wherein the probe apparatus has a fritting function for electrically conducting an object to be inspected and a probe pin using a fritting phenomenon.

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