Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1999-07-27
2001-08-07
Karlsen, Ernest (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S762010
Reexamination Certificate
active
06271674
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a probe card suitable for electrically testing a plurality of chips formed in a form of a matrix on a semiconductor wafer.
2. Prior Art
In general, there are formed a plurality of integrated circuit portions, i.e., IC chip portions (referred to merely as a chip or chips hereinafter) in a form of a matrix on a semiconductor wafer. Each chip has a rectangular shape, and each of its edge portions corresponding to each side of the rectangular chip has a plurality of electrode pads or an electrode portion. Chips constituting rows and columns of the matrix are aligned in every row and column.
Chips of this kind are subject to the electrical test for determining whether or not the circuit formed on each chip can operate in such a manner as defined in the specification thereof. Such an electrical test is often carried out, before separating chips in pieces from the wafer, that is, in the state that the chips stay on the wafer, by means of a probe card including a plurality of probes for pressing the electrode portion with their needle point. In the electrical test of this kind, if the test is performed on the chip by chip basis, it would take a very long time to complete the test of all the chips.
In order to obviate such a long and unnecessary time consuming work, there has been proposed a probe card which enables a predetermined number of chips on the wafer to be tested in one test. In order to perform the test using such probe card, the chips lying on the wafer are first divided into groups including some chips, for instance, a group consisting of some chips which are selected every other chip or every third chips lying on the wafer, or a series of chips aligned in the form of row or column on the wafer. Then, the test is carried out on such chip groups on the group by group basis, thereby reducing the number of tests needed for completing the test of all the chips on the wafer and shortening the time required for completing the same.
In case of the above-mentioned prior art probe card, however, since the chip group which can be tested simultaneously consists of chips selected every other chip or every third chip, or a series of chips aligned in the form of row or column, it is not possible to test simultaneously four chips arranged side by side across each of the imaginary boundary lines intersecting each other substantially in the cross-like shape, in other words, four chips located around the intersection of boundary lines. Accordingly, the number of electrical tests per wafer becomes large, and it takes a long time for completing the test of one wafer.
A probe card capable of testing adjacent four chips simultaneously has been disclosed by the Japanese Patent Application Public Disclosure (KOKAI) No. H9-283575. In this probe card, the same number of probes as the number of a lot of chips are fitted to a plurality of long supporters, and these supporters are arranged on the printed circuit board in a lattice-like form.
However, according to the probe card as described above, since a lot of probes have to be fitted to each supporter, the work for fitting the probes to the supporter are apt to become complicated. Especially, should there exist only one probe erroneously fitted to the supporter, the supporter itself will be rejected through the product inspection, thus worsening the production yield of the supporter and the probe, which in turn results in the rise in their manufacturing cost. Accordingly, it is required that the work for fitting the probes to the supporter be carried out more carefully.
Therefore, in the probe card for use in the test of chips formed on the semiconductor wafer, it is the most important thing that, while adjacent four chips located around the intersection portion of the boundary lines intersecting each other in the cross-like shape can be tested simultaneously, the work for putting probe blocks together in the lattice-like form should be facilitated.
SUMMARY OF THE INVENTION
A probe card according to the invention includes a base plate, a plurality of probe blocks having first and second probe groups including a plurality of probes, respectively, the probe blocks being fitted to the base plate substantially in a lattice-like form. Respective needle points of the probes belonging to the first and second probe groups are located on one and the other sides of each of imaginary boundary lines. The probe blocks located around a lattice intersection portion position the needle point parts of the probes located in the vicinity of the lattice intersection portion in the same direction with respect to their needle rear parts.
The probe blocks are arranged on the base plate. Therefore, it is not required to fit to each probe block the same number of probes as the number of electrode portions of a lot of chips. As a result, the number of probes to be fitted to each probe block can be reduced remarkably.
In the probe card, the needle points of the first and second probe groups located around the lattice intersection portion are made to oppose to the electrode portions belonging to the electrode group of one and the other of two adjacent chips located side by side across each of imaginary boundary lines respectively extending from the lattice intersection portion and are pressed against the corresponding electrode portions.
A plurality of probe blocks located around a lattice intersection portion position the front side portions of the probes located in the vicinity of said lattice intersection portion in the same direction, i.e., in a windmill-like manner. Therefore, a plurality of probes do not interfere with the work for combining a plurality of probe blocks in the lattice-like form, and it is possible to test simultaneously adjacent four chips arranged across each of the imaginary boundary lines intersecting each other substantially in the cross-like shape.
A plurality of probe blocks located around the lattice intersection portion may position, around the lattice intersection portion, the needle point parts of their probes on the same side with respect to their needle rear parts. With this, all the probes of the probe blocks are extended to the same side like the vanes of a windmill, so that the work for setting up the probes is made easier.
In the preferable embodiment of the invention, each probe block further includes a supporter for supporting the probes, and the probe card further comprises a probe set-up means. The probe set-up means includes a plurality of cross joints for joining the probe blocks together substantially in the cross-like form and fitting the joined probe blocks to the base plate substantially in the lattice-like form.
In the embodiments as described above, a plurality of probe blocks located around the lattice intersection portion can extend, around the lattice intersection portion, all of their front side portions in the same direction relative to the fitting position of the probes to the supporter. In this way, since all the front side portions of each probe block project on the same side, i.e., in a windmill-like manner from the supporter, the work for fitting the probes to the supporter is made easier.
A plurality of probe blocks located around the lattice intersection portion can include four probe blocks which radially extend and are combined so as to form substantially a cross shape. Each cross joint may combine four probe blocks together substantially in a cross shape and fit the combined probe blocks to the base plate. In this way, since it is possible to make each probe block correspond to one imaginary boundary line radially extending from the lattice intersection portion, the work for fitting the probes to the probe set-up means, the base plate or the supporter is made easier.
Alternatively, the cross joint may be arranged on the base plate with a predetermined space therebetween in the first direction in parallel to the base plate so as to extend in the second direction intersecting the first direction, each cross joint puts a plurali
Hasegawa Yoshiei
Hirai Yukihiro
Narita Satoshi
Sugiyama Tadashi
Tandai Takahiko
Christensen O'Connor Johnson & Kindness PLLC
Kabushiki Kaisha Nihon Micronics
Karlsen Ernest
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