JP2007024613A - Contact terminal and connector for semiconductor device inspection using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact terminal with an improved deposition prevention effect of a conductive metal on a contact part of the contact terminal, and to provide a connector for inspection on a semiconductor device. <P>SOLUTION: This contact terminal 1 makes electrical contact with an electrode of the semiconductor device. The maximum height Ry of surface roughness of the contact part 2 of the contact terminal 1 with the electrode is 10μm or less. The contact part 2 is characterized by being formed out of a carbon coating 7 containing metallic material. This connector for inspection uses this contact terminal 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contact terminal to be brought into contact with an electrode of a semiconductor device, and an inspection connection device using the contact terminal.

  A semiconductor device such as an IC package is provided with a large number of electrodes, and a conductive metal layer such as gold or solder is formed on the surface of these electrodes by plating or the like. Then, the inspection of the electrical characteristics or the like of the semiconductor device is performed by using a connection device for inspection having a plurality of contact terminals and bringing the contact terminals into electrical contact with the electrodes of the semiconductor device.

  In such a connection device for inspection, the contact terminal is repeatedly brought into contact with the electrode on which the conductive metal layer of the semiconductor device is formed. Therefore, a conductive metal such as solder adheres to the contact portion of the contact terminal with the electrode. The phenomenon that occurs. If the attached conductive metal is oxidized to increase the electrical resistance, contact failure may occur during connection inspection.

The contact resistance value of a conventional contact terminal is generally 0.1 to 50 mΩ in the initial stage, but an example in which the contact resistance value deteriorates to about several hundred mΩ when repeatedly used is known.
As a countermeasure against this, the contact terminals have been regularly cleaned and replaced. However, such measures reduce the productivity of the semiconductor production line and the life of the contact terminals.

Accordingly, the inventors of the present application have developed a contact terminal to which a conductive metal such as solder is difficult to adhere by forming a coating having low cohesiveness at the tip of the contact terminal, and disclosed in Patent Document 1. Patent Document 1 discloses a contact terminal characterized in that a carbon film containing a metal element having a property of forming carbide is formed on the surface of the tip of the contact terminal. Since the carbon coating containing the metal element has low cohesiveness with respect to the metal, adhesion of conductive metal such as solder to the contact terminal can be prevented.
JP 2002-318247 A (paragraphs 0030 to 0032, FIG. 5)

  However, there is a strong demand for contact terminals that can be used stably for a longer period of time in order to improve the productivity of semiconductor manufacturing lines. In addition, tin-copper-silver-based lead-free solder has been widely used to prevent environmental pollution. As a result, the problem of tin adhesion to the contact terminals has become prominent, further preventing metal adhesion. It has been demanded.

  Therefore, in the present invention, a contact terminal having an improved effect of preventing the conductive metal from adhering to the contact portion of the contact terminal, and a semiconductor device inspection having an improved effect of preventing the conductive metal from adhering to the contact portion of the contact terminal. An object is to provide a connection device.

In order to solve the above problems, in the present invention, the maximum height Ry in the surface roughness is set to 10 μm or less so that the contact portion with the electrode of the contact terminal becomes a smooth surface, and a carbon coating containing a metal element is formed in the contact portion. A contact terminal having a structure characterized by being formed is employed.
In addition, the structure includes a plurality of contact terminals having a maximum height Ry in a surface roughness of a contact portion with an electrode of the contact terminal of 10 μm or less, and a carbon coating containing a metal element formed on the contact portion. The connection device for inspection of semiconductor devices was adopted.

According to such a contact terminal, the effect of preventing the conductive metal from adhering to the contact portion of the contact terminal can be improved.
Moreover, if such a contact terminal is used, the connection device for test | inspection of the semiconductor device by which the adhesion prevention effect of the electroconductive metal to the contact part of a contact terminal was improved can be provided.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a perspective view illustrating an example of an inspection connection device 10 including a plurality of contact terminals 1 according to the present embodiment. In FIG. 1, it is assumed that the semiconductor device 11 is a QFP (Quad Flat Package) and the inspection connection device 10 is an IC socket. A large number of electrodes 12 are arranged at predetermined intervals on the outer periphery of the four sides of the semiconductor device 11, and a solder film that is a conductive metal layer is formed on the surface of each electrode 12.

  The plurality of contact terminals 1 of the inspection connection device 10 are embedded in a housing 20 formed of an insulating material such as a resin, and the contact portions 2 of the contact terminals 1 are located at positions corresponding to the electrodes 12 of the semiconductor device 11. Lined up and exposed. Furthermore, a part of an arm 5 to be described later is exposed outside the aligned contact portions 2.

  When inspecting the semiconductor device 11, first, the semiconductor device 11 is aligned with a predetermined position by the four positioning pins 21 protruding from the housing 20, and then the semiconductor device 11 is pressed from above as indicated by an arrow in FIG. 12 is brought into electrical contact with the contact portion 2 of the contact terminal 1. Note that the pressing may be performed manually or automatically using an air cylinder or the like.

FIG. 2 is a perspective view illustrating a state of contact between the contact terminal 1 and the electrode 12 according to the present embodiment.
The contact terminal 1 is provided with a contact portion 2 on a surface that can come into contact with the electrode 12 and a pin 3 for connecting to an external measuring instrument (not shown). Further, the contact terminal 1 is formed in a shape capable of pressing the contact portion 2 against the electrode 12 by a spring bias utilizing deflection. In the present embodiment, the spring is biased by using the deflection of the arm 5 extending from the support portion 4 in a cantilever shape.

  As described above, the semiconductor device 11 is pressed to electrically contact each electrode 12 of the semiconductor device 11 and the contact portion 2 of the corresponding contact terminal 1, and then an electrical inspection is performed. At this time, a part of the solder film of the electrode 12 is melted by heat generated by energization, and the contact portion 2 that is spring-biased contacts and separates while rubbing the electrode 12. Conventionally, it is considered that these two points are the main causes of the solder adhering to the surface of the contact portion 2. Furthermore, when a metal such as solder attached to the contact portion 2 is oxidized to form an oxide film, the contact resistance increases, resulting in a decrease in the reliability of the electrical inspection.

  FIG. 3 is an essential part enlarged view schematically showing a cross-sectional structure of the contact portion 2 of the contact terminal 1 according to the present embodiment. The contact portion 2 of the contact terminal 1 according to the present embodiment is formed of an amorphous carbon film 7 containing a metal element. The carbon film 7 having an amorphous structure has a low surface cohesiveness, and therefore adhesion of a molten metal such as solder is suppressed.

  Further, since the entire surface of the carbon coating 7 is formed with a smooth surface having a maximum height Ry of 10 μm or less in the surface roughness, even if the contact portion 2 makes contact or detachment by rubbing the electrode 12, Metals such as solder are difficult to be scraped off. For this reason, adhesion of solder or the like to the carbon film 7 forming the contact portion 2 can be prevented. In this way, it is possible to effectively prevent adhesion of metal such as solder on the entire surface of the contact portion 2 that can be in contact with the electrode 12.

  Below, the contact terminal 1 which concerns on this embodiment is demonstrated in more detail. The contact terminal 1 is processed into a predetermined shape using a metal such as Cu or Ni as a base material or an alloy mainly containing any of these metal elements, for example, beryllium copper, phosphor bronze, or nickel alloy, and the contact portion 2 Can be obtained by forming the carbon film 7 after polishing the portion where the film is formed to a predetermined surface roughness.

  Since the inspection connecting apparatus 10 according to this embodiment is intended for inspection of the semiconductor device 11 having a large number of electrodes 12, it is necessary to process a large amount of contact terminals 1 having the same shape from the base material. As a processing method suitable for this, press cutting, laser cutting, electric discharge cutting, cutting with a router, or the like can be used. However, when such a processing method is used, the cut surface of the contact terminal 1 is in a very rough state or a non-uniform state.

  Therefore, in this embodiment, after the contact terminal 1 is processed, it is polished in advance so that the maximum height Ry in the surface roughness of the portion where the contact portion 2 is formed is 10 μm or less. By setting the maximum height Ry to 10 μm or less in this polishing step, the maximum height Ry of the surface of the contact portion 2 can be set to 10 μm or less.

  Polishing of the contact portion 2 is performed by a known polishing method such as dry polishing using a polishing material or a grindstone containing an abrasive such as aluminum oxide in resin, rubber or nonwoven fabric, or mechanical / chemical polishing using a colloidal silica slurry. An abrasive with Ry of 10 μm or less can be selected as appropriate. Further, the smaller the maximum height Ry is, the more preferable it is to prevent adhesion of metal such as solder. However, in order to make the maximum height Ry less than 0.5 μm, a facility for maintaining a clean environment is required, resulting in an increase in manufacturing cost.

  The carbon film forming the contact portion 2 can be formed by various methods such as chemical vapor deposition (CVD), sputtering, and arc ion plating (AIP). It is preferable to apply a sputtering method or an AIP method because it is easy to form a carbon film with low electrical resistance or to easily introduce a metal element into the carbon film. In particular, the sputtering method is preferable because a high-quality carbon film 7 can be formed.

  That is, the structure of the carbon coating includes a diamond structure and a graphite structure, and in order to obtain sufficient hardness and low electrical conduction, an amorphous structure which is an intermediate structure between the two is desirable. According to the sputtering method, such a structure can be easily formed, and the mixing of hydrogen that inhibits electric conduction hardly occurs.

  Further, the carbon film forming the contact portion 2 can contain a metal element in order to reduce the electric resistance. As such a metal element, one or more of Ti, V, Nb, Zr, Mo, W, Ta, Hf, Cr, Mn, Fe, Co, and Ni can be appropriately selected and used. In particular, a carbon film containing at least 10 to 30 atomic% of W is excellent in preventing adhesion of metal such as solder.

  If the W content is less than 10 atomic%, the effect of preventing the adhesion of metal such as solder to the contact portion 2 is insufficient, and if the W content exceeds 30 atomic%, W oxide is likely to be generated. The reliability of the physical test is reduced. Furthermore, if the content of W in the carbon coating is 14 to 20 atomic%, the effect of preventing the adhesion of metals such as solder can be further enhanced, and the generation of W oxide can be more effectively suppressed.

  In order to contain a metal element in the carbon coating, the above sputtering method can be used. Specifically, a carbon film containing an intended metal element by using one carbon target and individual targets of each metal element to be contained in the carbon film, or a composite target in which these metal elements and carbon are mixed. Can be easily formed. Here, the composite target is one in which carbon and other metal elements are arranged in a mosaic or mixed in a form that is contained in a matrix.

  Further, as a modification of the present embodiment, in order to improve the adhesion of the carbon coating 7 to the base material, an intermediate layer having a gradient composition in which the ratio of carbon and metal element gradually changes between the carbon coating 7 and the base material. Can also be provided. Also in the case of providing the gradient composition intermediate layer, it is possible to easily form the gradient composition intermediate layer by preparing a plurality of targets by sputtering and adjusting the input power to each.

In addition, it is preferable that the thickness of the carbon film 7 shall be 0.5-1.0 micrometer. If the thickness of the carbon coating 7 is less than 0.5 μm, the carbon coating 7 is likely to be peeled off, and if it exceeds 1.0 μm, the electrical resistance of the contact portion 2 becomes high, which is not preferable. In addition, the carbon coating 7 that forms the contact portion 2 only needs to be formed only in a portion where the contact terminal 1 may come into contact with the electrode 12 of the semiconductor device 11.
In the inspection connecting device 10 using the contact terminal 1 described above, the contact terminal 1 is disposed at a predetermined position of the resin housing 20 as shown in FIG. Can be attached and manufactured.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not of a nature limiting the present invention, and any design changes may be made in accordance with the spirit of the embodiments and examples of the invention. It is included in the technical scope of the present invention. In the embodiment, the case where the inspection connecting device 10 is an IC socket has been described as an example. However, the contact terminal 1 of the present invention can also be applied to a probe card and a spring probe.

<Example 1>
A contact terminal 1 having a predetermined shape is punched out from a thin nickel plate, and the contact portion 2 is formed with an abrasive containing fine aluminum oxide powder (manufactured by Sumitomo 3M: trade name <3M> lapping film sheet 3 μAO). Roughly polished to a maximum surface height Ry of 15 μm, then finer polishing material (manufactured by Sumitomo 3M: trade name <3M> lapping film sheet 0.3 μAO: polishing with aluminum oxide having a particle size of 0.3 μm After the material was processed into a smooth surface with Ry of 10 μm or less, a carbon coating 7 containing W was formed by the following procedure.

First, a graphite target and a chromium target are placed in a commercially available magnetron sputtering apparatus, the contact terminal 1 is placed so as to face them, and after evacuating to 1 × 10 ⁻⁴ Pa or less, the Ar gas is set at a pressure of 2 mmTorr. The plasma was introduced into the chamber until it was, and Ar plasma was generated by applying a high frequency voltage, and sputter etching of the contact portion 2 by Ar ions was performed at Rf power: 500 watts for 3 minutes. Note that portions other than the contact portion 2 of the contact terminal 1 were masked. Further, a small amount of W chip was placed on the graphite target to form a composite target, and the formed carbon film 7 was adjusted to contain about 14 atomic% of W. As a result, a contact terminal 1 having a structure in which a chromium film / an intermediate layer having a gradient composition containing chromium, graphite, and W / a carbon film 7 containing W and a carbon film 7 containing W was laminated on the base material nickel was manufactured.

  And the maximum height Ry in the surface roughness of the contact part 2 and arithmetic mean roughness Ra were measured. Hereinafter, the contact terminal 1 according to the first embodiment may be referred to as a polished product. The W content in the carbon coating 7 was confirmed by energy dispersive X-ray analysis (EDX).

  Next, the contact terminal 1 is subjected to 2000 times with an energizable plate (hereinafter referred to as a test plate) whose surface is tin-plated under the conditions of a load of 30 g to 200 g, a stroke of 0.2 mm to 0.9 mm, and a current of 1 A or less. After contacting, the adhesion state of the foreign material on the surface of the contact part 2 was observed with a scanning electron microscope (SEM), and the tin adhesion amount was evaluated by EDX. The SEM was measured with SEMEDXIII Type N manufactured by Hitachi, and the EDX was measured with EMAXEX-2000 manufactured by Horiba.

  Note that the maximum height Ry and arithmetic mean roughness Ra are exceptionally high and low and are regarded as scratches visually by using a 20x objective lens with a VK85550 ultra-deep shape measurement microscope manufactured by Keyence. A range of 100 × 200 μm was extracted from a portion having no valley and automatically measured. Ry was obtained by calculating the sum of the height Yp from the average line to the highest peak and the depth Yv to the lowest valley. Ra was obtained by calculating the average value after summing the absolute values of deviations from the average surface to the measurement curved surface. Note that the above-described microscope uses reflection of laser light, and measures Ry and Ra using data of all dots by measuring a 100 × 200 μm range with 139 × 277 pixels.

<Comparative Example 1>
A contact terminal 1 was manufactured in the same manner as in Example 1 except that the polishing in Example 1 was not performed. Then, the same analysis and measurement were performed by the same method and apparatus as in Example 1. (Hereinafter, the contact terminal 1 of Comparative Example 1 may be referred to as an unpolished product.)

<Comparative Example 2>
The contact terminal 1 in which the contact portion 2 was formed by gold plating by electrolytic plating instead of the carbon coating 7 containing W was not manufactured in Example 1. Then, the same analysis and measurement were performed by the same method and apparatus as in Example 1. (Hereinafter, the contact terminal 1 of Comparative Example 2 may be referred to as a gold-plated product.)

  The SEM photograph of the contact part 2 of each contact terminal 1 which concerns on Example 1 and Comparative Examples 1-2 before and after making it contact with a test plate to FIG. Table 1 shows the maximum height Ry, arithmetic average roughness Ra of the contact portion 2 of each contact terminal 1 according to Example 1 and each comparative example before contact with the test plate, and tin adhered after contact. The mass concentration of is shown. Here, the mass concentration of tin means the content (%) of tin when the total mass of carbon, W, Ar, and tin detected by EDX is 100.

In the SEM photograph of the surface of the polished product of Example 1 (FIG. 4a), no significant change was observed before and after the contact, and no significant foreign matter was observed over the entire surface.
On the other hand, in the SEM photograph after contact of the non-polished product of Comparative Example 1 (FIG. 4b), the adhesion of foreign matter was observed near the upper left, and from the upper left in the SEM photograph of the gold-plated product of Comparative Example 2 (FIG. 4c). Further noticeable adhesion of foreign matter was observed from the lower left. By EDX analysis, it was confirmed that these foreign substances were tin.

  Furthermore, when the adhesion amount of tin measured by EDX was compared, the adhesion amount to the polished product of Example 1 was 2% or less of Comparative Example 1 (non-polished product) and 1 / 1,000 or less of Comparative Example 2. It was. From this, it was clearly shown that the amount of tin attached to the contact terminal 1 according to the present invention is extremely small compared to the conventional one.

From the above, by forming the contact portion 2 with the carbon coating 7 containing W having a maximum surface height Ry of 10 μm or less, there is a remarkable effect that adhesion of foreign matter (tin) to the surface can be effectively prevented. It became clear that it was obtained.
From another point of view, the contact portion 2 is formed of the carbon coating 7 containing W having an arithmetic average roughness Ra of 0.50 μm or less on the surface, so that foreign matter (tin) adheres to the surface. It can be said that it can be effectively prevented.

  In addition, it turns out by the comparison of the comparative example 1 and the comparative example 2 that the higher adhesion prevention effect is acquired by forming the contact part 2 with the carbon film 7 containing W rather than gold plating.

It is a perspective view which shows an example of the connection apparatus for a test | inspection provided with two or more contact terminals which concern on this embodiment. It is a perspective view showing a mode of contact of a contact terminal and an electrode concerning this embodiment. It is a principal part enlarged view which represents typically the cross-section of the contact part of the contact terminal which concerns on this embodiment. (A) is a surface SEM photograph before and after contact of the contact portion 2 of each contact terminal according to Comparative Example 1 and (c) of Comparative Example 2;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Contact terminal 2 Contact part 7 Carbon film 10 Connection apparatus 11 for inspection 11 Semiconductor device 12 Electrode

Claims (3)

A contact terminal in contact with an electrode of a semiconductor device,
The maximum height Ry in the surface roughness of the contact portion of the contact terminal with the electrode is 10 μm or less,
The contact terminal is formed of a carbon film containing a metal element.   2. The contact terminal according to claim 1, wherein the surface of the contact portion is formed by mechanical chemical polishing or dry polishing.   A connection device for inspection of a semiconductor device, comprising a plurality of contact terminals according to claim 1.