Probe for testing a semiconductor integrated circuit

Details Probe for testing a semiconductor integrated circuit Probe for testing a semiconductor integrated circuit

1996-12-23

2001-09-25

Nguyen, Vinh P. (Department: 2858)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S754090

Reexamination Certificate

active

06294922

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a probe for measuring electrical characteristics of a semiconductor integrated circuit, manufacture of the same, and a probe card assembly of vertically operative type employing the same which avoids undesireable contact and offers convenience in the work of exchanging a probe. The concept of the probe card assembly is explained in U.S. Pat. No. 5,134,365 granted Jul. 28, 1992.
DESCRIPTION OF THE RELATED ART
A conventional art of the vertically operative type probe card assembly will be described with reference to
FIGS. 24 and 25
, attached.
A conventional art of the vertically operative type probe card assembly includes, as shown in
FIG. 24
, a plurality of probes
850
, and board
860
fastening probes
850
, and housing members
870
mounted on the underside of board
860
.
The probe
850
is generally shaped in a needle work, of which a front part includes contact portion
851
for contacting onto electrode
710
of semiconductor integrated circuit
700
and a back part includes connecting portion
852
to be connected by connector
854
, such as gold line, to a wiring pattern formed on board
860
.
Therein flexible portion
853
in a generally lateral U shape is formed between contact portion
851
and connecting portion
852
. The flexible portion
853
is intended, as shown in
FIG. 25
, to bend or flex for keeping a desired contact pressure when a contact is made between contact portion
851
and electrode
710
.
Housing members
870
include two guide boards
871
,
872
provided with through holes
871
A,
872
A, and a pair of walls
823
for fastening two guide boards
871
,
872
with board
860
. Through holes
871
A,
872
A in two guide boards
871
,
872
are provided for insertion of contact portions
851
of probes
850
and arranged to align to positional pattern of electrodes
710
of semiconductor integrated circuit
700
for measurement.
On the other hand, board
860
is provided on its upperside with predetermined wiring pattern (not shown) and with a through hole
861
into which connecting portion
852
of probe
850
is inserted. See FIG.
25
. Connecting portion
852
inserted in through hole
861
will be connected to the wiring pattern above.
However, such conventional probe card assembly of vertically operative type as noted has been found to have problems or difficulties as below:
Normally such a probe card assembly of vertically operative type has been mounted with several hundreds or several thousands of probes in commercial operation, and replacement of some probes is necessary during operation when such probes are found to be worn out or damaged.
This replacement or exchange work of probes needs preliminary work of removing solder mass applied to the wiring pattern bonded with the connecting portions, and then taking the probes away from the board. However, lateral U letter shaped flexible portion
853
of each probe
850
hinders itself, due to steric figuration, from being pulled out through the through hole
861
of board
860
. For this reason, disassembling of housing members
870
is necessary prior to exchange probes
850
. The way of removing the probes
850
without disassembling thereof is possible when the probes can be cut at the flexible portions
853
. However such approach will incidentally injure other probes which are needless to be exchanged in the case of commercial operation where so many probes are equipped with the probe card assembly of vertically operative type, and therefore impossible in fact.
If such approach of exchange work should be possible, it requires, after removal of probes
850
of interest from board
860
, inserting new probes
850
through the through hole
861
of board
860
as well as through holes
871
A,
872
A of two guide boards
871
,
872
, and uniformizing heightwise positions of the contact portions
851
of new probes with those of other unchanged probes, and arranging orientations of the flexible portions
853
so as to be free from contact each other, and then soldering for bonding the connecting portions
852
with the wiring pattern. Thus, in the case of a commercial probe card assembly equipped with so many probes, the work of exchanging probes is labor intensive which requires performance by a skilled person with an excess amount of cautions.
Further, a conventional probe card assembly has had such measurements as: about 6 mm vertical thickness of the board, about 10 mm vertical length of the housing members, thus a probe has been about 20 mm length. Recent semiconductor integrated circuits have much progressed in employing higher speed signals and in turn require best shorter probes and wiring patterns in order to minimize signal attenuation and cross-talk troubles in advance. However, the probe length employed in the probe card assembly of vertically operative type has at shortest about 20 mm in the state of art, though further shortening has been desired as to probe length.
In addition, probes have been normally manufactured from tungsten wires which were produced by drawing tungsten rods manufactured by powder metallurgy. For this cause, drawing of tungsten wire extends flaw or defect to extend along the length of probes, so that cut sections of the drawn tungsten wires, that is, contact portions have more trend of forming irregularities, and thus the probe contact portions are easier to attract foreign matters than other portions.
In order to overcome such problems heretofore, the probes which have been applied to contact with electrodes are subject to cleaning for removing foreign matters from the contact portions. Otherwise the prior step is taken to make the contact portions round. However, the cleaning requires regular maintenance and as a result causes suspension of the operation employing the probes, and making round contact portions includes difficulty in forming a correct semi circle at the end of the contact portion and also difficulty in processing many probes concurrently, thus poor production efficiency.
On the other hand, some electrodes are in shapes of semi circular bump. Such electrodes should be applied by probes having a flat end of the contact portion, but such type of probes tends to change the shape of the end by the cleaning and in turn to make it difficult to obtain correct measurements subsequently.
SUMMARY OF THE INVENTION
The present invention intends to offer a probe card assembly of vertically operative type employing shorter length probes with the merit of facilitating the work of exchanging used probes even in the case where so many probes are equipped, and the probes suitable for such application, and process of manufacturing such probes.
A probe of the present invention features in a shape of generally needle work, and in having a buckling portion to bend or to buckle, upon contact onto an electrode of semiconductor integrated circuit at the end of its contact portion, wherein the probe has a generally round section and its buckling portion is thinner than other portions excepting the end of the contact portion, and the contact portion and the buckling portion are formed to be linear.
A process for manufacturing a probe of the present invention features generally in the process of manufacturing a probe for making a contact onto an electrode of semiconductor integrated circuit and in including a step of heating up to be molten the contact portion to be used to make a contact onto the electrode, and a step of forming a minuscule ball from the molten part.
A first probe card assembly configuration of vertically operative type features in including: a plurality of probes having a buckling portion to bend or to buckle, upon a contact by the end of its contact portion onto an electrode of semiconductor integrated circuit; and a first board provided with a first wiring pattern connected with a connecting portion of the probe; and a second board removably fastened with the first board and provided with a second wiring pattern connected with the first wiring pattern; and housing members mounted with the secon

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