JPH0628276B2 - Probe needle for measuring electrical characteristics of semiconductor wafers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a probe needle for measuring electrical characteristics of IC, LSI, etc. on a wafer.

(Prior Art) Conventionally, as a probe needle that can measure the electrical characteristics of IC, LSI, etc. on the wafer 1 shown in FIG. 5 even in a high frequency region, it is shown in FIG. The coaxial probe needle 6 is formed by projecting the signal line 4 at the center of the tip of the coaxial cable 3 and attaching the ground portion 5 to the outer periphery of the tip of the coaxial cable 3 so that its tip is parallel to the tip of the signal line 4 by about 200 μ. X, Y, Z of the measuring instrument 7 as shown in FIG.
A method of setting parameters on an arm 8 which is movable in the axial direction and bringing it into contact with a pad 2 such as an IC or LSI on the wafer 1 to measure parameters is adopted.

(Problems to be solved by the invention) By the way, in the coaxial probe needle 6, the signal line 4 and the ground portion 5 do not have a coaxial structure over several mm at the tip of the coaxial cable 3, so that the characteristic impedance at that portion. It changed, and accurate electrical characteristics could not be measured in the high frequency range. In addition, it was impossible to realize multiple terminals with this structure. Further, the coaxial probe needle 6 has a problem that crosstalk, that is, noise is large because the signal line 4 and the ground portion 5 are not shielded.

On the other hand, the development of high density and high speed ICs and LSIs has recently been advanced, and as a prober for evaluating these, stable characteristic impedance, multiple terminals, and reliable padding on wafers have been developed. It is necessary to provide a probe needle capable of reducing various contacts and crosstalk, and the development thereof is urgent.

Therefore, the present invention is intended to provide a probe needle that can achieve stabilization for setting characteristic impedance, increase in number of terminals, reliable contact and reduction of crosstalk, and that can accurately measure electrical characteristics in a high frequency region. is there.

(Means for Solving Problems) In a probe needle of the present invention for solving the above problems, a plurality of transmission lines are provided in parallel on a dielectric substrate, and the tip of each transmission line is raised upward. Then, an elastic material is filled between the dielectric plate below the ridges to form the ridges as contact parts, and the ground lines are arranged in parallel on the dielectric plates on both sides of each transmission line. It is characterized by being provided.

(Embodiment) An embodiment of the probe needle of the present invention will be described with reference to FIG. 1. 10 is made of alumina (Al ₂ O ₃ ) and has a length of 40 mm and a width of
A transmission board 11 made of Cu having a thickness of 3 μm and a width of 150 μm is provided in parallel in three rows at a distance of 200 μm on the dielectric substrate 10 having a thickness of 10 mm and a thickness of 0.6 mm. I am. The tip of each transmission line 11 is bent upward in a side trapezoidal shape to bulge, and an elastic body, for example, polyimide 15 is filled between the trapezoidal ridge 12 'and the lower dielectric substrate 10. The raised portion 12 'serves as a contact portion. Each transmission line
The thickness of 3μ on the dielectric substrate 10 between 11 and both sides,
The ground line 14 made of Cu and having a width of 150 μ is connected to the transmission line 11.
They are arranged in parallel with an interval of 200μ.

As described above, in the probe needle 16 'of the present invention, since the transmission lines 11 are provided in three rows in parallel on the dielectric substrate 10, the transmission lines are
11 has a strip line structure, and the characteristic impedance of the transmission line 11 does not change and is constant at any part. Therefore, the probe needle 16 'of FIG. 2 of the embodiment is set on the arm 8 movable in the X, Y and Z axis directions of the measuring instrument 7 as shown in FIG. in contact with 2, it was measured parameter, in a high frequency region, in this example could accurately measuring electrical characteristics at a high frequency of 30GH _Z. Further, even when this measurement is repeated, a ridge 12 'is provided at the tip of each transmission line 11, and the elastic body 15 is filled under the ridge 12' so that the ridge 12 can be elastically deformed. Therefore, in the measurement of the parameters, when the pad 2 of the IC, LSI or the like on the wafer 1 to be measured is contacted, the contact portion of each transmission line 11 is not crushed, and is always reliably and stably contacted. Furthermore, since the ground line 14 is provided between the transmission lines 11, the transmission lines 11 are shielded, crosstalk is reduced, and noise is significantly reduced.

Although the dielectric substrate 10 of the probe needle 16 'in the above embodiment is made of alumina, it may be made of quartz. Further, although the transmission line 11 has three columns in the above-mentioned embodiment, it is not limited to this, and any number of columns of two or more may be used.
It may be 0 columns. Furthermore, on the surface of the transmission line 11, Au
It may be plated.

(Effects of the Invention) As can be seen from the above description, since the probe needle of the present invention has a plurality of transmission lines provided in parallel on the dielectric substrate, the transmission line has a strip line structure. Therefore, the setting of the characteristic impedance can be stabilized, the characteristic impedance can be made constant in any part of each transmission line, and a multi-terminal can be realized by a plurality of lines of transmission lines. Moreover, in the probe needle of the present invention, since the graduation line is provided between the transmission lines, the transmission lines are shielded, crosstalk is reduced, and noise is significantly reduced. Moreover, in the probe needle of the present invention, the tip ends of the plurality of transmission lines are separated from the dielectric substrate and raised, and the raised portions are used as contact portions to fill the electrically insulating elastic body under the raised portions to raise the raised portions. Since it is elastically deformable, the contact portion of each transmission line is not crushed when it comes into contact with the object to be measured, and all of them are always reliably and stably contacted. Thus, high density, high speed ICs and LSIs on wafers
It is possible to accurately, surely and stably measure the electrical characteristics in a high frequency region such as.

[Brief description of drawings]

FIG. 1 is a perspective view showing a probe needle of a comparative example, FIG. 2 is a perspective view showing an embodiment of the probe needle of the present invention, and FIG.
FIG. 4 is a schematic view showing a usage state of the probe needle shown in FIG. 4, FIG. 4 is a perspective view of a conventional coaxial probe needle, and FIG. 5 is a schematic view showing a usage state of the coaxial probe needle shown in FIG.

Claims (1)

[Claims] 1. A transmission line is provided in parallel in a plurality of rows on a dielectric substrate, and the tip of each transmission line is raised upward so that an elastic material is provided between the transmission line and the dielectric substrate below the raised portion. A probe needle for measuring electrical characteristics of a semiconductor wafer, characterized in that the protrusions are filled with the protrusions to form contact portions, and ground lines are provided in parallel on the dielectric substrate on both sides of each transmission line.