Semiconductor device manufacturing: process – With measuring or testing
Reexamination Certificate
2000-03-29
2001-01-16
Chaudhuri, Olik (Department: 2814)
Semiconductor device manufacturing: process
With measuring or testing
C324S754090
Reexamination Certificate
active
06174744
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to structures of a probe card and a micro contact pin to be mounted on the probe card, which are used in testing performance of a semiconductor integrated circuit device formed on a semiconductor wafer, and a method of producing the probe card and contact pins. More particularly, this invention relates to a structure of a micro contact pin and a probe card having a large number of micro contact pins to test high density semiconductor integrated circuit devices on a semiconductor wafer.
BACKGROUND OF THE INVENTION
In testing a semiconductor integrated circuit on a semiconductor wafer such as a silicon wafer, a special machine such as a wafer prober is used which includes a probe card having a plurality of contact pins. The contact pins establish electrical connections with electrodes on the surface of the wafer to transmit signals therebetween.
FIGS. 4 and 5
show an example of structure in a conventional probe card for testing such semiconductor integrated circuits on a semiconductor wafer.
In
FIG. 4
, the probe card has contact pins
19
, an insulation plate
17
and coaxial cables
18
for testing a semiconductor device
7
which is formed on a silicon wafer
1
. The semiconductor device
7
to be tested has a plurality of electrodes
2
such as bonding pads on its surface.
The contact pins
19
in this case are called pogo pins which have an elastic function with a telescopic structure. Each of the contact pins
19
is provided to face the corresponding electrode
2
of the test device
7
. The electric connection will be established when the ends of the contact pins
19
are pressed on the electrodes
2
. The insulation plate
7
is to place the contact pins
19
in a predetermined position and fix the contact pins in such a position. The coaxial cables
18
are connected to the upper parts of the contact pins
19
for establishing electrical communication between the test device
7
and a test system
28
shown in a block diagram of FIG.
7
.
Another example of conventional probe card is shown in FIG.
5
. The probe card of
FIG. 5
includes a plurality of electrode bumps
21
, a membrane
20
, a probe frame
22
, screws
23
and coaxial cables
18
. The electrode bumps
21
are provided on the surface of the membrane
20
to meet the electrodes of the test device
7
on the silicon wafer
1
. In addition to the electrode bumps
21
, the membrane
20
is further provided with circuit patterns connected to the bumps
21
for transmitting electric signals. Namely, the electrode bumps
21
are electrically connected with the corresponding coaxial cables
18
through the circuit patterns.
A plunger
24
, screws
23
, a spring
25
and a pressure sensor
26
are provided to establish up-down movements of the electrode bumps
21
and the membrane
20
. Thus, the electrode bumps
21
are pressed on the electrodes to form electric connections therebetween. A probe frame
22
supports the various components noted above and allows the up-down movements of the electrode bumps
21
.
The position of the electrode bumps
21
with respect to the electrodes
2
on the test device
7
is adjusted by positioning the plunger
24
in vertical and horizontal directions by the screws
23
. Thus, the communication by electric signals between the semiconductor device
7
under test and a semiconductor test system
28
(
FIG. 7
) will be made through the coaxial cables
18
.
Because of the increasing density and operation speed in the semiconductor integrated circuits, probe cards for testing the integrated circuits on the semiconductor wafer need to have contact pins with higher density and better impedance matching at the connection points. Further, because of the increasing density and the scale of the integrated circuits, the contact pins on the probe card are required to maintain the sufficient electric contact with the electrodes on the wafer even when the flatness of the wafer is fluctuated or deteriorated.
When the electrodes
2
of the test device
7
are aluminum electrodes, to secure the electric contact between the electrodes
2
and the contact pins on the probe card, it is also required to have a scrubbing function for removing an oxide film on the surface of the electrode
2
. This scrubbing function is considered to maintain the sufficient electric contact with high reliability.
In the conventional probe card using the contact pins
19
shown in
FIG. 4
, it is possible to make the tip of the contact pin
19
small enough to match the size of the electrode
2
on the wafer. However, because the contact pin
19
needs to have a sufficient size to maintain the enough mechanical rigidity, and the spaces for connection with the coaxial cables
18
must be provided, it is considered that the minimum distance between the contact pins
19
is limited to about 1 mm pitch.
In the conventional probe card using the electrode bumps
21
on the membrane
20
as shown in
FIG. 5
, it, is possible to have higher density of the electrode bumps than the density of the probe card using the contact pins
19
of FIG.
4
. However, the density of
FIG. 5
is still limited to the order of about 0.5 mm. Further, the example of
FIG. 5
is not adequate to overcome the deterioration of the flatness of the wafer surface since the electrode bump
21
is not independent from the others. By the same reason, the scrubbing function for removing the oxide film of the electrodes of the test device is not available.
Therefore, in the conventional probe card using the pogo pin type contact pins or the membrane having the bumps are not suitable to meet the requirement of the recent semiconductor integrated circuit having an ultra small pitch between the electrodes. It is necessary to develop a probe card and a contact pin structure having a new approach to overcome the dimensional limit and to meet the needs of the high density semiconductor device.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a contact structure for electrically connecting a contact pin with an electrode of a device to be tested formed on a semiconductor wafer which is capable of reducing the pitch between the adjacent contact pins to test a high density semiconductor device.
It is another object of the present invention to provide a contact structure for electrically connecting a contact pin with an electrode of a device to be tested with high stability and high reliability by overcoming the fluctuations of flatness of the electrodes of the device to be tested.
It is a further object of the present invention to provide a contact structure for electrically connecting a contact pin with an electrode of a device to be tested with high stability and high reliability by scrubbing a surface of the electrode by the contact pin.
It is a further object of the present invention to provide a probe card having a contact structure of the present invention and a production method of the contact structure of the present invention.
The contact structure of the present invention includes a micro contact pin having electric conductivity formed on one end of a beam which is movable in a vertical direction, and a piezoelectric element formed on the beam to drive the beam in the vertical direction. The beam is made of silicon on the surface of which is formed of a conductive thin film, and the micro contact pin has a pyramid shape. The piezoelectric element is a bimorph plate mounted on an upper surface of the beam or both upper and lower surfaces of the beam.
Another aspect of the present invention is a probe card for establishing electrical connections between electrodes of a plurality of semiconductor circuits on a wafer and a semiconductor test system. The probe card is formed of a plurality of micro contact pins formed on corresponding beams and positioned relative to the electrodes of all of the semiconductor circuit on the wafer where each of the micro contact pins has electric conductivity and is formed on one end of each of the beams which is movable in a vertical dire
Watanabe Takashi
Yoshida Minako
Advantest Corp.
Chaudhuri Olik
Muramatsu & Associates
Weiss Howard
LandOfFree
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