JP2006184081A - Probe pin for probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe pin capable of improving shock resistance by heightening the hardness of a tip part of a probe pin needle, and adjusting the hardness. <P>SOLUTION: In this probe pin 10 wherein the needle tip part 3a forms a contact part to an integrated circuit chip on a semiconductor wafer as a measuring object, at least the surface of the needle tip part 3a is coated with electroless PTFE-including nickel plating 5, to thereby heighten the surface hardness of the needle tip part 3a and improve shock resistance, and the surface hardness of the needle tip part 3a can be adjusted by adjusting the PTFE content rate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to probe pins for probe cards (hereinafter abbreviated as “probe pins”) for conducting energization inspection of integrated circuit chips on a semiconductor wafer.

  Hard and elastic tungsten, rhenium tungsten, beryllium copper alloy, etc. are used as probe pins for conducting energization inspection (wafer test) of integrated circuit chips in the manufacturing process of semiconductor wafers. Tungsten having excellent wear and toughness is often used.

  Tungsten is excellent for wear resistance, elastic force, toughness, hardness, etc., so it is a suitable material for probe pins composed of extremely thin wires with a diameter of several tens of microns. Due to frictional heat and heat generated by contact resistance when energized in contact with the circuit electrodes, the temperature of the needle tip rises and oxidation proceeds, and reacts with aluminum deposited on the integrated circuit, Aluminum oxide is generated and adhered to the needle tip portion (as a contact portion with respect to the integrated circuit chip on the semiconductor wafer as the object to be measured) by thousands to tens of thousands of contacts.

  When aluminum oxide adheres, the contact resistance of the needle tip portion increases, and the electrical conductivity is lowered to hinder the wafer test. Therefore, it is necessary to perform maintenance (cleaning) such as polishing the needle tip portion. Further, since the wafer test is interrupted during the cleaning process, there is a problem that the efficiency of the wafer test is deteriorated.

As one means for solving such a problem, PTFE (tetrafluoroethylene, trade name “ Probe pins with Ni plating containing Teflon ") have been developed. Although the probe pin described in Patent Document 1 can also achieve the purpose as described in the same publication, the plating film is easily cracked, recessed, or peeled off, and the electrical characteristics are affected by repeated contact with the integrated circuit chip. Inferior in durability, and as described later, there is also a problem in impact resistance.
JP 2001-74777 A

  The present invention solves the above-mentioned problems of the probe pin described in Patent Document 1, improves the impact resistance of the needle tip, and measures the long life of the plating film, thereby providing an integrated circuit for the probe pin. An object of the present invention is to provide a probe pin that can withstand repeated contact with a chip many times and that is not inferior to a conventional probe pin in wear resistance.

  In order to achieve the above object, the present invention provides a probe pin in which a needle tip portion forms a contact portion with respect to an integrated circuit chip on a semiconductor wafer as an object to be measured. It is a means of solving the problem by covering with plating.

  By adopting such a configuration, that is, at least the surface of the probe tip portion of the probe pin is coated with the electroless PTFE-containing Ni plating, the surface hardness of the probe pin tip portion is increased and the impact resistance is improved. An excellent probe pin can be obtained. Nevertheless, the friction coefficient of the tip of the needle can be kept at a value that is almost the same as that of the conventional probe pin, so that it is possible to obtain a probe pin that is not inferior to the conventional probe pin in terms of wear resistance. .

  Moreover, by setting the hardness of the electroless PTFE-containing Ni plating to Hv 300 to 900, it was possible to obtain a probe pin with extremely excellent impact resistance. When the hardness of the electroless PTFE-containing Ni plating is set to this value, a probe pin that can be used 300,000 times or more can be obtained as described later.

  An electroless PTFE-containing Ni plating is applied to the base material to form a plating layer having a precipitation hardness of Hv 200 to 500, and then heat treated to obtain an electroless PTFE-containing Ni plating with a hardness of Hv 300 to 900. As a means to solve the problem.

  Furthermore, the precipitation hardness of the electroless PTFE-containing Ni plating is controlled by adjusting the PTFE particle content in the electroless PTFE-containing Ni plating, thereby providing a means for solving the problems.

  The deposition hardness of the electroless PTFE-containing Ni plating can be adjusted by adjusting the content of PTFE particles in the electroless PTFE plating, and the hardness of the electroless PTFE-containing Ni plating can be increased by heat treatment. Therefore, PTFE plating (film) having high hardness and arbitrary hardness can be easily formed on the surface of the probe tip portion of the probe pin.

In the probe pin obtained according to the present invention, at least the surface of the probe tip portion of the probe pin is coated with the electroless PTFE-containing Ni plating, whereby the surface hardness of the probe pin needle tip portion can be increased. As a result, a probe pin excellent in impact resistance can be obtained, and as will be described later, it is possible to obtain a probe pin that can endure use about 10,000 times or more.
Nevertheless, since the slipperiness of the needle tip, that is, the coefficient of friction is almost the same as that of a conventional probe pin, the aluminum oxide film of the integrated circuit chip is placed on the needle tip of the probe pin when contacting the probe pin with the integrated circuit chip. Can be reduced. As a result, it is possible to maintain a stable contact resistance value, and it is possible to obtain a probe pin that is held in substantially the same manner as a conventional probe pin in terms of reducing the number of cleanings.

  Moreover, by adjusting the PTFE particle content of the electroless PTFE-containing Ni plating, the hardness of the plating can be adjusted, and if necessary, by further adding a heat treatment, the plating hardness can be further adjusted. A probe pin having a needle tip having a hardness suitable for the use mode can be obtained.

Hereinafter, the present invention will be specifically described with reference to embodiments shown in the drawings.
1 is a cross-sectional view of the probe pin, and FIG. 2 is an enlarged cross-sectional view of a portion A in FIG.

1 and 2 show a so-called “cantilever type probe pin (of the same type as the probe pin of Patent Document 1)”, and in FIGS. 1 and 2, reference numeral 10 denotes a probe pin.
Tens to hundreds of probe pins 10 are arranged on a printed wiring board (not shown) of a probe card for energization inspection of an integrated circuit chip on a semiconductor wafer. Re-W alloy and beryllium alloy are used as base materials.

  The probe pin 10 is formed of a main body portion 1 and a tapered linear taper portion 2 having a predetermined length formed at one end portion (tip side) of the main body portion 1, and a pointed end of the linear taper portion 2. 3 has a small-diameter needle tip portion 3a.

  As an example of dimensions, the main body 1 has a wire diameter of 0.07 to 0.7 mm, an overall length of 25 to 100 mm, a length of the linear tapered portion 2 of 0.3 to 6 mm, and a needle tip. The portion 3a has a diameter of 0.02 mm or less.

  In order to improve the adhesion of the electroless PTFE-containing Ni plating to the entire surface of the probe pin 10 processed into such a shape, the base Ni plating film 4 is formed by electroplating.

The probe pin 10 on which the base Ni plating film 4 is formed is then subjected to electroless PTFE-containing Ni plating (film) by electroless PTFE-containing Ni plating on the entire surface of the linear tapered portion 2 including the pointed end 3. 5 is formed.
The electroless PTFE-containing Ni plating 5 can be formed, for example, by immersing the tip side of the main body 1 in a solution of approximately 87 ° C. to 90 ° C. containing PTFE particles for about 30 minutes. By adjusting the content of PTFE particles in the solution, the precipitation hardness of the electroless PTFE-containing Ni plating 5 can be adjusted (see Table 1 below for this point, “Hardness Hv heat treatment in Table 1). The value in front is equivalent to me).
Theoretically, the initial purpose can be achieved by covering only the needle tip portion 3a formed at the tip end 3 with the electroless PTFE-containing Ni plating 5. Since it is extremely technically difficult to coat only the area portion with the electroless PTFE-containing Ni plating 5, in this embodiment, up to about 40% of the tip side of the main body 1 is immersed in the plating solution, By plating the entire portion soaked in the plating solution, the needle tip portion 3a is covered with the electroless PTFE-containing Ni plating 5.

  As shown in Table 1, the probe pin 10 to which the electroless PTFE-containing Ni plating 5 is applied has a precipitation hardness corresponding to the content of PTFE particles. If necessary, the hardness of the electroless PTFE-containing Ni plating 5 can be further increased by subjecting it to a heat treatment. This heat treatment can be performed, for example, by a conventional method of exposing in an atmosphere of 300 ° C. for about 1 hour.

Next, Table 1 shows the relationship between the content of PTFE particles in the solution of the probe pin 10 of this embodiment and the precipitation hardness of the electroless PTFE-containing Ni plating 5, and the experimental results on the effect of heat treatment.
The aspect of the test piece subjected to the experiment is as follows.
Overall shape: the shape shown in FIGS.
Total length: 100 mm (conventional example, any of the present invention products 1, 2, 3)
Wire diameter: 0.10 mm (conventional example, products 1, 2, and 3 of the present invention)
Length of linear taper portion: 3 mm (conventional example, products of the present invention 1, 2, 3)
Type of plating: conventional example; PTFE-containing Ni plating by electroplating
Invention products 1, 2, and 3; electroless PTFE-containing Ni plating Plating length: 5 mm (conventional example, both of the invention products 1, 2, and 3)
Plating thickness: 5 μm (conventional example, any of the present invention products 1, 2 and 3)
Base material: W
The plating solution (in the case of the present invention products 1, 2, and 3) comprises a nickel salt, a reducing agent, a complexing agent, a pH adjuster, a stabilizer, and a PTFE-Ni particle dispersant.

As shown in Table 1, when the PTFE particle content was 3%, an electroless PTFE-containing Ni plating (film) 5 having a precipitation hardness of hardness Hv400 was obtained.
By subjecting this to heat treatment, the hardness of the plating (film) could be increased to about Hv750.

  Furthermore, in the probe pin 10 manufactured in the above-described process, the electroless PTFE-containing Ni plating 5 formed on the needle tip portion 3a of the pointed end 3 contains PTFE particles. As indicated by the numerical values of the friction coefficients in Table 1, the probe pin 3 acts to improve the slipping property when the tip 3a of the tip 3 of the reference probe pin 10 contacts the integrated circuit chip. As a result, the adhesion of aluminum to the needle tip 3a of the probe pin 10 can be reduced, and the number of cleanings can be reduced and stable contact resistance can be maintained. Become. At the same time, wear resistance is improved.

Moreover, as shown in Table 1, it is possible to adjust the hardness of the electroless PTFE-containing Ni plating 5 by adjusting the PTFE particle content in the electroless PTFE-containing Ni plating 5, and it is also possible to increase the plating hardness by heat treatment. Therefore, it is possible to obtain the probe pin 10 including the needle tip portion 3a having a hardness suitable for the usage mode. In addition, the probe pin is superior to the conventional electroplating method in terms of the impact resistance of the probe tip 10a, but is not inferior in terms of wear resistance. You can get a pin.
In the above description, a cantilever type probe pin is taken as an example, but it goes without saying that the same effect can be obtained with a vertical type probe pin.

It is sectional drawing of the probe pin of one Embodiment of this invention. FIG. 2 is an enlarged cross-sectional view showing an arrow A portion in FIG.

Explanation of symbols

1: Body part 2: Linear taper part 3: Pointed end 3a: Needle tip part
4: Ni plating film 5: Electroless PTFE-containing Ni plating (film)
10: Probe pin

Claims (5)

  In the probe pin in which the needle tip portion forms a contact portion with respect to the integrated circuit chip on the semiconductor wafer as the object to be measured, at least the surface of the needle tip portion is covered with electroless PTFE-containing Ni plating Probe pin for probe card.   2. The probe pin for a probe card according to claim 1, wherein a base material of the probe pin is tungsten or rhenium tungsten.   3. The probe pin for a probe card according to claim 1, wherein the electroless PTFE-containing Ni plating film has a hardness of Hv 300 to 900. 4.   The electroless PTFE-containing Ni plating having the hardness Hv of 300 to 900 is formed by subjecting the base material to electroless PTFE-containing Ni plating to form a plating layer having a precipitation hardness of Hv200 to 500, and then heat-treating this. The probe pin for a probe card according to claim 3. 5. The probe pin for a probe card according to claim 4, wherein the precipitation hardness is adjusted by adjusting the content of PTFE particles in the electroless PTFE-containing Ni plating.