Method for testing semiconductor components using interposer

Details Method for testing semiconductor components using interposer Method for testing semiconductor components using interposer

2002-04-16

2004-11-16

Nguyen, Vinh P. (Department: 2829)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S765010

Reexamination Certificate

active

06819127

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to the testing and assembly of semiconductor components, such as semiconductor dice and packages having contact balls. More particularly, this invention relates to an interposer for electrically engaging semiconductor components having contact balls.
BACKGROUND OF THE INVENTION
Ball grid array technology is increasingly employed in the manufacture of high performance semiconductor components requiring a high input/output capability. A ball grid array semiconductor component includes external contacts in the form of balls arranged in a dense grid pattern (e.g., rows and columns). Exemplary ball grid array semiconductor components include BGA packages, chip scale packages, and bumped bare dice.
The balls in the ball grid array can have different shapes, such as spherical, hemispherical, or dome. Typically the balls comprise solder, which permits the semiconductor components to be surface mounted, or alternately flip chip mounted, to a mating component such as a printed circuit board.
Recent developments in ball grid array technology permit the balls to be made smaller and with tighter pitches. For example, for fine ball grid array (FGBA) components, the balls can have a diameter as small as about 0.127 mm (0.005 inch), and a center to center pitch as small as about 0.228 mm (0.008 inch). As the balls become smaller and closer, it becomes more difficult to make electrical connections with the balls for testing and for surface mounting the components in the fabrication of electronic assemblies.
For testing applications, sockets are typically employed to hold the components, and to make the temporary electrical connections with the contact balls on the components. The socket then interfaces with a test board, or other substrate, in electrical communication with test circuitry.
FIGS. 1A and 1B
illustrates a prior art component
10
that includes contact balls
12
. As used herein the term “contact balls” refers to external contacts on the component
10
in electrical communication with integrated circuits or other electrical elements contained on the component
10
. The contact balls
12
can have any conventional shape that provides a raised contact surface. By way of example, representative shapes include spherical, hemispherical, dome, bump and conical. In addition, the contact balls
12
have a diameter “D” and a pitch “P”. A representative range for the diameter D can be from about 0.127 mm (0.005 inch) to 0.762 mm (0.030 inch). A representative range for the pitch P can be from about 0.228 mm (0.008 inch) to 2.0 mm (0.078 inch).
FIG. 2A
illustrates a prior art test system
14
for testing the component
10
. The test system
14
includes multiple sockets
16
mounted to test sites
22
on a test board
18
. Each socket
16
is designed to hold a component
10
.
As shown in
FIG. 2B
, the test sites
22
on the socket
16
include contacts
24
in electrical communication with test circuitry
20
. The contacts
24
are adapted to make temporary electrical connections with the contact balls
12
on the component
10
. In the embodiment illustrated in
FIG. 2B
the contacts
24
are mounted in openings
28
in the socket
16
and include y-shaped segments
26
that physically and electrically engage the contact balls
12
. A force applying mechanism (not shown) associated with the socket
16
presses the component
10
against the contacts
24
with a force F. This permits native oxide layers on the contact balls
12
to be penetrated by the y-shaped segments
26
. In addition to the y-shaped segments
26
, the contacts
24
on the socket
16
also include terminal segments
30
that plug into electrical connectors
32
in the test board
18
. As shown in
FIG. 2C
, the pitch P of the contacts
24
matches the pitch P (
FIG. 1B
) of the contact balls
12
. As shown in
FIG. 2D
, the pitch P of the terminal segments
30
of the contacts
24
also matches the pitch P (
FIG. 1B
) of the contact balls
12
. This type of contact
24
is sometimes described as a “straight through” contact.
Alternately, as shown in
FIGS. 2E and 2F
, another type of contact
24
A is adapted to exert a force F on the contact balls
12
. As shown in
FIG. 2E
, an opening
28
A receives the contact ball
12
with the contact
24
A in an unactuated position with a zero insertion force. As shown in
FIG. 2F
, actuation of the contact
24
A presses the contact
24
A against the contact ball
12
with a force F. The contact
24
A can be constructed with a mechanical lever or rocker as is known in the art. This type of contact
24
A is adapted to exert a wiping action on the contact ball
12
which breaks through native oxide layers.
One problem with the conventional socket
16
is that it is difficult to accommodate contact balls
12
having a pitch of less than about 0.65 mm. Specifically, the contacts
24
(or
24
A) cannot be made as small, or as close, as the contact balls
12
. This is especially true with sockets having “straight through” contacts
24
. Also, components that mate with the socket
16
, such as the test board
18
, must include mating electrical connectors
32
for the contacts
24
(or
24
A). The mating electrical connectors
32
may require more space to fabricate than the contacts
24
(or
24
A), making fabrication of the test board
18
difficult.
Another problem with the conventional socket
16
is that the contacts
24
(or
24
A) can only make electrical connections with one size and pitch of contact balls
12
. Often times a component
10
will be initially manufactured with contact balls
12
having a relatively large size (e.g., 0.40 mm) and pitch (e.g., 1.0 mm). However, due to design and fabrication process improvements, the size and pitch of the contact balls
12
will shrink. This requires that the socket
16
be redesigned and replaced each time the component
10
changes. This type of socket
16
is expensive to make, and becomes more expensive as the size and pitch of the contact balls
12
decreases. The test boards
18
for the sockets
16
must also be redesigned to accommodate the replacement sockets. In general, redesign and replacement of the sockets and test boards represents a significant expense for semiconductor manufacturers.
The present invention is directed to an interposer which configures test sockets for testing components having different sizes and pitches of contact balls. In addition, the interposer permits test sockets to be constructed with external contacts having a pitch that is greater than a pitch of the contact balls on the component. The interposer can also be utilized in assembly applications for modifying electronic assemblies to accommodate components having different contact balls.
SUMMARY OF THE INVENTION
In accordance with the present invention, an interposer for electrically engaging semiconductor components having contact balls is provided. The interposer can be used to fabricate test sockets and test systems, and to perform test methods. In addition, the interposer can be used in the fabrication of electronic assemblies wherein semiconductor components having contact balls are mounted to a mating substrate, such as a printed circuit board.
The interposer, broadly stated, comprises: a base with external contacts; an interconnect on the base for electrically engaging contact balls on a semiconductor component; and an alignment member on the base for aligning the component to the interconnect.
In a test embodiment, the interposer configures a test socket for testing semiconductor components having contact balls. In addition, the interposer is interchangeable with other interposers adapted to electrically engage contact balls on other components. This permits the same test socket to be used with different interposers to test components having different configurations of contact balls. Accordingly, the interposer can be “tailored” for a particular component, while the test socket remains “universal” in character.
In an assembly embodiment, the interposer configures a substrate (e.g.

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