Packaging and interconnection of contact structure

Details Packaging and interconnection of contact structure Packaging and interconnection of contact structure

2001-08-13

2002-05-07

Karlsen, Ernest (Department: 2858)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S762010, C257S692000, C257S696000

Reexamination Certificate

active

06384616

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an electronic packaging and interconnection of a contact structure, and more particularly, to an electronic packaging and interconnection for mounting a contact structure on a probe card or equivalent thereof which is used to test semiconductor wafers, semiconductor chips, packaged semiconductor devices or printed circuit boards and the like with increased accuracy, density and speed.
BACKGROUND OF THE INVENTION
In testing high density and high speed electrical devices such as LSI and VLSI circuits, high performance probe contactors or test contactors must be used. The electronic packaging and interconnection of a contact structure of the present invention is directed to the application of testing and burn-in testing of semiconductor wafers and dies, but not limited to such applications and is inclusive of testing and burn-in test of packaged semiconductor devices, printed circuit boards and the like. However, for the convenience of explanation, the present invention is described in the following mainly with reference to a probe card to be used in semiconductor wafer testing.
In the case where semiconductor devices to be tested are in the form of a semiconductor wafer, a semiconductor test system such as an IC tester is usually connected to a substrate handler, such as an automatic wafer prober, to automatically test the semiconductor wafer. Such an example is shown in
FIG. 1
in which a semiconductor test system has a test head
100
which is ordinarily in a separate housing and electrically connected to the test system through a bundle of cables. The test head
100
and the substrate handler
400
are mechanically connected with one another by means of a manipulator
500
and a drive motor
510
. The semiconductor wafers to be tested are automatically provided to a test position of the test head by the substrate handler such as a wafer prober.
On the test head, the semiconductor wafer to be tested is provided with test signals generated by the semiconductor test system. The resultant output signals from the semiconductor wafer under test are transmitted to the semiconductor test system wherein they are compared with expected data to determine whether IC circuits (chips) on the semiconductor wafer function correctly or not.
As shown in
FIGS. 1 and 2
, a test head
100
and a substrate handler
400
are connected with each other through an interface component
140
. The interface component
140
includes a performance board
120
which is typically a printed circuit board having electric circuit connections unique to a test head's electrical footprint, such as coaxial cables, pogo-pins and connectors. The test head
100
includes a large number of printed circuit boards
150
which correspond to the number of test channels (tester pins) of the semiconductor test system. Each of the printed circuit boards
150
has a connector
160
to receive therein a corresponding contact terminal
121
of the performance board
120
.
In the example of
FIG. 2
, a “frog” ring
130
is mounted on the performance board
120
to accurately determine the contact positions relative to the substrate handler
400
such as a wafer prober. The frog ring
130
has a large number of contact pins
141
formed, for example, by ZIF connectors or pogo-pins, connected to the contact terminals
121
, through coaxial cables
124
.
FIG. 2
further shows a structural relationship between the substrate handler
400
, the test head
100
and the interface component
140
when testing a semiconductor wafer. As shown in
FIG. 2
, the test head
100
is placed over the substrate handler
400
and mechanically and electrically connected to the substrate handler through the interface component
140
. In the substrate handler
400
, a semiconductor wafer
300
to be tested is mounted on a chuck
180
. A probe card
170
is provided above the semiconductor wafer
300
to be tested. The probe card
170
has a large number of probe contactors (contact structures)
190
, such as cantilevers or needles, to contact with circuit terminals or contact targets or contact pads in the IC circuit of the semiconductor wafer
300
under test.
Electrical terminals or contact receptacles of the probe card
170
are electrically connected to the contact pins
141
provided on the frog ring
130
. The contact pins
141
are also connected to the contact terminals
121
of the performance board
120
via the coaxial cables
124
where each contact terminal
121
is connected to the printed circuit board
150
of the test head
100
. Further, the printed circuit boards
150
are connected to the semiconductor test system main frame through the cable bundle
110
having several hundreds of cables therein.
Under this arrangement, the probe contactors (needles or cantilevers)
190
contact the surface of the semiconductor wafer
300
on the chuck
180
to apply test signals to the IC chips on the semiconductor wafer
300
and receive the resultant signals of the IC chips from the wafer
300
. The resultant output signals from the semiconductor wafer
300
under test are compared with the expected data generated by the semiconductor test system to determine whether the IC chips in the semiconductor wafer
300
properly perform the intended functions.
FIG. 3
is a bottom view of the probe card
170
of FIG.
2
. In this example, the probe card
170
has an epoxy ring on which a plurality of probe contactors
190
called needles or cantilevers are mounted. When the chuck
180
mounting the semiconductor wafer
300
moves upward in
FIG. 2
, the tips of the cantilevers
190
contact the contact targets such as contact pads or bumps on the wafer
300
. The ends of the cantilevers
190
are connected to wires
194
which are further connected to transmission lines (not shown) formed in the probe card
170
. The transmission lines in the probe card
170
are connected to a plurality of electrodes
197
which further contact the pogo pins
141
of FIG.
2
.
Typically, the probe card
170
is structured by a multilayer of polyimide substrates having ground planes, power planes, signal transmission lines in many layers. As is well known in the art, each of the signal transmission lines is designed to have a characteristic impedance such as 50 ohms by balancing the distributed parameters, i.e., dielectric constant and magnetic permeability of the polyimide, inductances and capacitances of the signal paths within the probe card
170
. Thus, the signal transmission lines are impedance matched to achieve a high frequency transmission bandwidth to the wafer
300
under test. The signal transmission lines transmit a small current during a steady state of a pulse signal and a large peak current during a transition state of the device's outputs switching. For removing noise, capacitors
193
and
195
are provided on the probe card
170
between the power and ground planes.
An equivalent circuit of the probe card
170
is shown in
FIGS. 4A-4E
to explain the limitations of bandwidth in the conventional probe card technology. As shown in
FIGS. 4A and 4B
, the signal transmission line on the probe card
170
extends from the electrode
197
, the strip line (impedance matched line)
196
, the wire
194
and to the needle (cantilever)
190
. Since the wire
194
and needle
190
are not impedance matched, these portions function as an inductor L in the high frequency band as shown in FIG.
4
C. Because of the overall length of the wire
194
and needle
190
is around 20-30 mm, the value of the inductor L is not trivial, resulting in the significant frequency limitation in testing a high frequency performance of a device under test.
Other factors which limit the frequency bandwidth in the probe card
170
reside in both power and ground needles shown in
FIGS. 4D and 4E
. If a power line can provide large enough currents to the device under test, it will not seriously limit the operational bandwidth in testing the device. However, because the series connected wire
194
and needle
190
for supplying

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