JP2002303637A - Probe pin and contactor having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a needle single crystal-made probe pin capable of contacting an electrode having an Al or solder base having a surface oxide film and provide a probe card having the probe pin. SOLUTION: The pin is a semiconductor measuring vertical probe pin 1 made of a needle single crystal has a conductive film on the surface. The top end 2 of the pin 1 contacting an electrode 3 of an object under test has a round edge of 0.7 μm or less in radius, as seen in its lengthwise direction. When the probe pin contacts the electrode 3 of the object in a buckled state, the load perpendicular to the electrode surface per unit electrode contact area of the top end of the probe pin is 0.03-0.30 mN/um<2> and the top end face of the probe pin is inclined at an inclination angle of 87 degrees or less to the center line of the pin in the lengthwise direction. A probe card has the probe pin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe card for measuring electrical characteristics of a semiconductor integrated circuit or the like, and more particularly, to a probe card which constitutes a probe card and which is an important part of a probe for contacting an electrode of the semiconductor circuit or the like, and the probe The present invention relates to a probe card having pins connected to a circuit.

[0002]

2. Description of the Related Art In a process of manufacturing a semiconductor integrated circuit or the like, generally, at the stage when a large number of chips are formed on a semiconductor wafer, the electrical characteristics of each chip are measured to judge the quality of operation characteristics. For this measurement, a probe card in which a large number of probe pins are implanted according to the electrode shape of the device under test is used.

In general, a probe card has a flatness of a virtual surface formed by a plurality of probe pin tips, a flatness of an electrode of an object to be inspected, and an evaluation in order to bring a plurality of probe pins into contact with electrodes. An error such as parallelism between the two when incorporated in a device is absorbed and a load necessary for stabilizing the contact resistance value is applied. For this reason, the probe pins are designed so that the space between the tip portion that comes into contact with the device under test and the portion of the probe card fixed to the substrate is elastically bent. The amount of bending of the probe pin is called overdrive.

[0004] With the recent miniaturization and high integration of semiconductors, the pitch of probe pins has been narrowed. In this case, even though it is necessary to increase the accuracy of the probe pin tip position, when the diameter of the probe pin is reduced and the necessary overdrive is applied for tens of thousands to hundreds of thousands of times,
There is a problem that the plastic deformation of the probe pin occurs and the position accuracy of the tip of the probe pin deteriorates. Further, in recent wafer tests, high-temperature measurement for testing a wafer while it is heated to about 130 ° C. has become widespread, and there has been a problem of deterioration in positional accuracy due to temperature.

At present, most of the probe pins used are manufactured by implanting individual wires made of W into a printed wiring board. It is becoming difficult to meet the demands in both aspects of the manufacturing method and probe pin tip position accuracy.

Therefore, a method of applying a needle-like single crystal formed by VLS growth has been proposed (JP-A-5-1986).
No. 36, JP-A-5-215774, JP-A-5-215774
-218156), by these methods,
It has become easy to manufacture a high-density probe card with a narrow pitch, and it is possible to arrange probe pins with high precision.

The probe pin obtained by the above method has a structure in which the vertical pin buckles and bends when the probe pin is brought into contact with the electrode of the device under test and overloaded.
The probe pins are thin and long, so that they do not break due to buckling even if they load the necessary overdrive.
Since a needle-shaped single crystal that is easily bent is used, the load applied perpendicularly to the surface of the electrode of the test object has a very small value of 10 mN or less. When the buckling deformation, the probe pin slightly scratches the electrode surface of the object to be inspected. Contact characteristics can be obtained. On the other hand, most of semiconductor electrodes are electrodes based on Al, solder, or the like, and these electrode surfaces have an oxide film. In the probe pin using the needle-shaped single crystal, the load is small, and the probe tip has a small dimension to scratch the electrode surface, so that the oxide film cannot be broken, and it cannot be used for semiconductor applications having these electrodes. . To cope with this problem, the size of the needle-shaped single crystal was adjusted to increase the load applied in the direction perpendicular to the surface of the electrode, but electrical continuity between the probe pin and the electrode was confirmed, but the probe pin The conductive film at the tip is remarkably deformed, the probe pin is easily damaged, and when the number of contacts is increased, an oxide film is deposited on the tip of the probe pin to make it impossible to conduct electricity.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a probe card using a needle-like single crystal, which can be brought into contact with an electrode having a surface oxide film and made of Al or solder as a base material. .

[0009]

SUMMARY OF THE INVENTION The present invention relates to a vertical probe pin for measuring semiconductors, which is made of a needle-like single crystal and has conductivity provided on its surface, wherein the probe pin has a tip as viewed in the longitudinal direction of the probe pin. When the radius of the edge is 0.7 μm or less, when the probe pin buckles and comes into contact with the electrode of the device under test, a load applied in the vertical direction of the surface of the electrode is applied. The value divided by the contact area is in the range of 0.03 mN / μm 2 or more and 0.30 mN / μm 2 or less, and the tip surface of the probe pin is
A probe card having an inclination angle of not more than 87 degrees with respect to a pair at a center line in the longitudinal direction of the probe pin, and having the probe pin.

A probe card comprising a needle-like single crystal of Si, at least the tip of which is a vertical probe pin for semiconductor measurement, made conductive by silicide, and having the probe pin.

Alternatively, the probe card is a vertical probe pin for measuring a semiconductor, which is made of a needle-like single crystal and has at least the tip portion doped to be conductive, and has the probe pin.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The present invention relates to a probe pin 1 having a needle-like single crystal made conductive as shown in FIG. 1 shows a state in which the probe pin buckles due to the overdrive load and the tip end surface 2 of the probe pin is in contact with the electrode 3.

As the material of the needle-like single crystal, a material formed by, for example, VLS growth can be used. Specifically, Si, LaB6, Ge, α-Al2O3, Ga
As, GaP, MgO, NiO, SiC, InGa and the like. Among them, Si of the same material as the semiconductor is preferable because it has the same characteristics such as the coefficient of thermal expansion and the positional accuracy of the probe pin is hardly changed even at a high temperature. In general, the thickness of the acicular single crystal is several to 100 μm, and the length is several hundred μm to several mm.

As shown in FIG. 2, in order to make the needle-shaped single crystal 4 conductive, a conductive film 5 is generally provided on the surface of the needle-shaped single crystal 4, and this conductive film 5 is made of Au or an Au alloy. , Cu
Can be formed by various known methods such as a plating method, a vapor deposition method, and a sputtering method. For example, when the conductive film is provided by a plating method, the needle-like single crystal 4 is subjected to a base plating treatment of Ni-P or Cr or the like, and then Au or Au-N which is a low electric resistance metal.
There is also a method of plating a surface layer of i, Au-Co, Au-Cr, Au-Cu or the like. Further, in order to maintain the durability of the contact portion of the conductive film 5 with the electrode, Pd, P
t, Rh, Ir metal or Pd alloy with Pd added to metals such as Ag, Cu, Pt, Au, etc .; Ag, Sn, In, Zn,
A method has been proposed in which a contact material 6 such as an Ag alloy to which an oxide such as Cu is added is coated only on the tip of the probe pin (Japanese Patent Application Laid-Open Nos. 10-38918 and 2000-22).
No. 7440). The conductive film in the present invention means a film showing conductivity, and the material is not limited.

When the probe pin 1 is formed by covering the surface of the needle-like single crystal with a conductive film, if the radius of the edge of the probe pin 1 in the longitudinal direction is larger than 0.7 μm, the probe pin 1 The tip has a small dimension that scratches the electrode surface, cannot break an oxide film on the electrode surface, and cannot contact an electrode having a surface oxide film, such as Al or solder, as a base material.

Therefore, as a method for reducing the radius of the edge of the probe pin 1 in the longitudinal direction to 0.7 μm or less, for example, there is a method of polishing the probe pin tip surface 2 with a wrapping film or the like. Alternatively, there is a method of making the conductive film of the probe pin 1 thinner. However, if the conductive film of the entire probe pin is made thinner, the electric resistance of the probe pin becomes higher, and the probe pin becomes unsuitable as a contactor. Therefore, the tip of the probe pin is masked with a resist or the like so that the thickness of the conductive film is thicker on the side surface of the probe pin and thinner on the tip portion. It is also possible to remove a part of the conductive film by etching to make it thinner.
In the present invention, the method of setting the radius of the edge of the tip of the probe pin in the longitudinal direction to 0.7 μm or less is not limited to the above method.

When the probe pin 1 is formed by coating a conductive film on the surface of the needle-shaped single crystal and the radius of the edge of the probe pin 1 in the longitudinal direction is 0.7 μm or less, the electrode 3 The value obtained by dividing the vertical load on the surface by the area where the tip of the probe pin is in contact with the electrode 3 is 0.03 mN.
If it is smaller than / μm 2, the dimension at which the tip of the probe pin scratches the electrode surface is too small to make contact with the electrode having the surface oxide film. On the other hand, for the probe pin 1, the value obtained by dividing the vertical load on the surface of the electrode 3 by the area where the tip of the probe pin is in contact with the electrode 3 is 0.30 mN / μm.
If it is larger than 2, the conductive film coated on the needle-shaped single crystal will be significantly deformed, or the probe pin will be damaged, and the durability as a probe will be lost.

Therefore, a value obtained by dividing the load in the vertical direction of the surface of the electrode 3 by the area of the tip of the probe pin in contact with the electrode 3 is controlled within the range of 0.03 to 0.30 mN / μm 2. To do so, the radius of the edge of the tip of the probe pin viewed in the longitudinal direction, the length of the probe pin, or the diameter of the probe pin may be adjusted. That is, in order to reduce the value obtained by dividing the load in the vertical direction of the surface of the electrode 3 by the area where the tip of the probe pin is in contact with the electrode 3, the edge of the tip of the probe pin viewed in the longitudinal direction is required. The radius may be increased, the probe pin may be lengthened, or the probe pin may be narrowed. Conversely, in order to increase the value obtained by dividing the vertical load on the surface of the electrode 3 by the area where the tip of the probe pin is in contact with the electrode 3, the edge of the tip of the probe pin viewed in the longitudinal direction is required. May be reduced, the probe pin may be shortened, or the probe pin may be thickened. In the present invention, the method of controlling the value obtained by dividing the load in the vertical direction of the surface of the electrode 3 by the area of the tip of the probe pin in contact with the electrode 3 is not limited.

A probe pin 1 is formed by coating the surface of the needle-shaped single crystal with a conductive film. The edge of the tip of the probe pin 1 when viewed in the longitudinal direction is 0.7 μm or less. The value obtained by dividing the load in the vertical direction by the area where the tip of the probe pin is in contact with the electrode 3 is 0.03 to 0.3.
0mN / μm2, the probe pin 1
When the inclination angle of the probe pin tip surface 2 with respect to the longitudinal center line exceeds 87 degrees, buckling of the probe pin causes
When the tip of the probe pin rubs against the electrode, an oxide film is deposited on the tip of the probe pin, and a conduction failure occurs as the number of contacts increases.

As a method of inclining the contact surface of the vertical probe pin using the needle-shaped single crystal with the object to be inspected, at least the probe pin is pushed into a rotating disk-shaped wrapping tape. A method has been proposed in which polishing is performed in a state where the vicinity of the tip is bent and deformed (see Japanese Patent Application Laid-Open No. 10-148646). The amount of pushing the probe pin into the tape containing this abrasive,
By adjusting the polishing time and the rotational speed of the disk in a state in which the vicinity of the tip of the probe pin is bent and deformed, the inclination angle of the probe pin tip surface 2 with respect to the center line in the longitudinal direction of the probe pin of the present invention can be adjusted to 87. The degree can be easily reduced. Note that, in the present invention, the method of forming an inclination angle on the probe pin tip surface 2 with respect to the center line in the longitudinal direction of the probe pin is limited to the method of polishing at least the vicinity of the tip of the probe pin in a bent state. Not something.

On the other hand, in the present invention, as a method for making at least the tip portion of the needle-like single crystal of Si conductive with silicide, Ni, Ti, Co, Pt,
After depositing Pdi, Mo, Nb, or the like on the surface of the acicular single crystal by a CVD method, a sputtering method, a vapor deposition method, or the like, silicide is formed by a known method such as annealing in an inert gas atmosphere. Thereby, the needle-shaped single crystal can be made conductive. However, even if the entire surface of the needle-shaped single crystal is silicided, the resistance value of the entire needle-shaped single crystal is high,
It is necessary to form a conductive film, such as Au, which is a low-resistance metal for the purpose of conducting, on a side surface other than the tip portion of the needle-like single crystal.

Further, in the present invention, as a method for making at least the tip portion of the acicular single crystal conductive by doping,
It can be carried out using various known methods such as a gas doping method and an ion implantation method. For example, after polishing the tip of a needle-like single crystal grown by the VLS method, a doped epitaxial layer is grown on the surface of the needle-like single crystal using a gas-doping CVD apparatus. Thereby, the needle-like single crystal can be made conductive. However, even if an epitaxial layer doped on the entire surface of the needle-shaped single crystal is grown, the resistance of the entire needle-shaped single crystal is high. It is necessary to form a conductive film such as Au which is a low electric resistance metal.

In the present invention, the tip of the probe pin means that the probe pin does not cover the side face of the probe pin with a conductive film such as Au, which is a metal having a low electrical resistance, for the purpose of making it conductive. In a region where a thin conductive film is coated to reduce the radius of the edge of the tip seen to 0.7 μm or less, or a needle-like single crystal is made conductive by silicide or doping, in the longitudinal direction from the tip of the probe pin. It is preferably 200 μm or less. If the length of the tip of the probe pin is longer than 200 μm, the electric resistance of the probe pin increases, and the probe pin becomes unsuitable for a contactor.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. [Examples and Comparative Examples] <Preparation of Intermediate> Proposed method (JP-A-8-30)
No. 4456, JP-A-9-61462), a needle-like single crystal was VLS-grown on an SOI substrate by the following method. An Au deposited film having the same pattern shape as that of the wiring substrate was formed on the SOI wafer by photolithography. Further, Au is placed at a predetermined position where a needle-like single crystal is grown by photolithography and plating.
A bump was formed. Next, by using an etching solution with a strong acid, a part of the exposed Si
By using the etchant of (1), an Au vapor-deposited film was formed, and by using the etchant of strong acid again, a wiring line composed of a Si thin film having a convex Si base under the Au bump was formed. . The circuit board having this wiring line was heated to 950 ° C. in a reaction tube, and a mixed gas of silicon tetrachloride and hydrogen was flown to obtain a needle-like single crystal at the position where the Au bump was. In this example and the comparative example, a probe pin having 450 probe pins arranged at a pitch of 45 μm was used. In the above operation, a contactor intermediate having the probe pin 1 using the needle-shaped single crystal was prepared by adjusting the size of the Au bump so that the diameter of the needle-shaped single crystal was 15 μm. And

<Examples 1 to 6> A commercially available wrapping film containing diamond particles was attached to a disk having excellent flatness, and a contactor appropriately selected from the samples was placed at a position off the center of rotation of the disk. It was arranged so that the tip of the intermediate was in contact. The needle-like single crystal was installed so that the longitudinal direction was perpendicular to the rotation plane of the disk. By pressing down the contactor intermediate body in the vertical direction from the contact position and rotating the disk, the tip was polished while bending the needle-shaped single crystal in the rotational direction of the disk.

In the polishing, in order to make the probe pin have a predetermined length, the operation of contacting the contactor intermediate body with the wrapping film and then pushing it down by 2 μm to polish for 20 seconds was repeated. The wrapping film is a resin film containing diamond particles having an average particle size of 0.1 μm. The rotation speed of the disk was 1000 rpm, and polishing was performed at a position 25 to 35 mm away from the rotation center of the disk. After the needle-shaped single crystal reached the target length, the amount of depression was polished at 10 μm or 30 μm for 5 seconds and pulled up to obtain a needle-shaped single crystal having a tilt angle of 88 ° or 85 ° at the tip end surface. . The target length of the acicular single crystal was 1200 μm or 1500 μm.

Next, using an electroless Ni plating solution in an alkaline bath, N
An i film was formed. Then, mask the probe pin tip with a resist ink that is alkali-resistant and solvent-soluble,
A 1 μm-thick conductive film was formed on the surface of the Ni film on the side surface of the probe pin using an electrolytic Au plating solution in an alkaline bath. Further, by removing the resist ink at the tip of the probe pin with xylene, a probe pin having a Ni conductive film at the tip of the probe pin was prepared. By adjusting the time of Ni plating, samples having a Ni plating film thickness of 0.2 μm (Examples 1 and 3) and 0.6 μm (Examples 2 and 4) were prepared. In addition, all the chemicals, such as the plating solution and the resist ink, used in the above operation were commercial products.

Further, after Ni was vapor-deposited on the needle-like single crystal, annealing was performed at 400 ° C. for 30 minutes in a nitrogen atmosphere, so that the surface portion of the needle-like single crystal was Ni silicide. Thereafter, by performing the same operation as that after forming the Ni film in Examples 1 to 4, a probe pin having Ni silicide at the tip of the probe pin (Example 5) was formed.

Further, the needle-shaped single crystal is subjected to a heat treatment at 1180 ° C. for 10 minutes in a mixed gas atmosphere containing silicon tetrachloride, hydrogen, and a PH3 doping gas of 10 ppm with respect to hydrogen, thereby obtaining a surface of the needle-shaped single crystal. Was formed with P-doped Si. Then, by performing the same operation as that after forming the Ni film in Examples 1 to 4, the P-doped Si
(Example 6) was prepared.

With respect to the contactor obtained by the above operation, the probe pin was observed with a scanning electron microscope from the side, and
The taper angle, which is the inclination angle with respect to the center line in the longitudinal direction of the probe pin, and the radius of the edge of the tip when the probe pin was seen in the longitudinal direction were measured. The load applied to the tip of the probe pin was measured using a commercially available load cell. Thereafter, a probing durability test described later was performed to examine the change in the contact resistance with the Al solid wafer, and further, the deformation of the tip of the probe pin after 10,000 times of contact was observed. Table 1 shows the results. In the probing durability test, an overdrive was applied to an Al solid wafer at 40 μm, a cycle time was 175 msec, and a contact time was 125 msec.
Was performed under the following conditions. An optical microscope photograph of the contact mark with the probe pin on the Al solid wafer was taken, and the area of the contact mark measured from the photograph was defined as the area where the tip of the probe pin was in contact with the electrode 3. The load applied to the tip of the probe pin was divided by this value to calculate the unit area load of the contact portion. Using a commercially available digital multimeter, the change in the contact resistance was measured at the rate of A once every 100 contacts.
The resistance with the l-solid wafer was measured, and the maximum value of the dispersion of the measured values for 100 times was shown. The deformation of the pin tip was observed with an optical microscope (400 magnification).

[0031]

[Table 1] Examples

<Comparative Examples 1 to 3> The tip of the needle-shaped single crystal was appropriately selected from the contactor intermediates, and an inclination angle of 88 degrees was formed with respect to the longitudinal center line of the needle-shaped single crystal. A sample was prepared by performing the same operation as in Example 3 using the sample (Comparative Example 1). In addition, the same operation as in Examples 1 to 4 was performed to adjust the Ni plating treatment time, so that N
A sample in which the thickness of the i-plated film was 2.0 μm was prepared (Comparative Example 2). Samples were prepared by polishing the needle-shaped single crystal with the target lengths of 2800 μm and 800 μm and performing the same operation as in Example 2 (Comparative Examples 3 and 4). The same evaluation as in Examples 1 to 6 was performed on the contactors obtained by these operations. Table 2 shows the results. In Comparative Example 1, conduction was confirmed at the start of the test,
Due to the increase in the number of contacts, the display value of the digital multimeter became 1 MΩ or more, and conduction could not be secured. On the other hand, in Comparative Examples 2 and 3, the display value of the digital multimeter became 1 MΩ or more from the start of the test, and electrical continuity could not be confirmed. Further, in Comparative Example 4, several tens of contacts with the electrode
A part of the probe pin was broken and could not contact the electrode. In addition, the tip of the probe pin that had not been broken after 10,000 contacts was significantly deformed.

[0033]

[Table 2] Comparative example

[0034]

As is clear from the examples, the probe pin and the contactor using the needle-shaped single crystal of the present invention can be electrically connected to the electrode having the surface oxide film, and the contact resistance varies. It is useful because it has a characteristic that the tip of the probe pin is less deformed even when the overdrive is applied 10,000 times.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a probe pin of the present invention is in contact with an electrode in a buckled state.

FIG. 2 is a sectional view showing an example of a conventional probe pin.

[Explanation of symbols]

 1 Probe pin using needle-like single crystal 2 Probe pin tip surface 3 Electrode 4 Needle-like single crystal 5 Conductive film 6 Contact material

Claims (4)

[Claims] 1. A vertical probe pin for semiconductor measurement which is made of a needle-shaped single crystal and has conductivity provided on its surface, wherein the edge of the tip of the probe pin viewed in the longitudinal direction has a radius of:
0.7 μm or less, and when the probe pin buckles and comes into contact with the electrode of the test object, the load applied in the vertical direction of the surface of the electrode is the area where the tip of the probe pin is in contact with the electrode. 0.03 to 0.30 mN / μm 2
And the tip end surface of the probe pin has an inclination angle of 87 degrees or less with respect to a longitudinal center line of the probe pin. 2. A vertical probe pin for semiconductor measurement which is made of a needle-like single crystal of Si and has a surface provided with conductivity, wherein at least the tip of the probe pin is made conductive with silicide. Probe pin to 3. A vertical probe pin for semiconductor measurement which is made of a needle-like single crystal and has conductivity provided on the surface thereof, wherein at least the tip of the probe pin is doped and made conductive by a needle-like single crystal. A probe pin, characterized in that there is a probe pin. 4. A probe card having the probe pins according to claim 1, 2, 3 or 4.