Electrical connectors – With coupling movement-actuating means or retaining means in... – Including compound movement of coupling part
Reexamination Certificate
2002-05-29
2003-07-15
Gilman, Alexander (Department: 2833)
Electrical connectors
With coupling movement-actuating means or retaining means in...
Including compound movement of coupling part
C439S259000
Reexamination Certificate
active
06592389
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the testing of electronic integrated circuits, and more particularly the invention relates to sockets for receiving packaged integrated circuits for test purposes.
The packaged integrated circuit typically includes a polymer or ceramic housing for a semiconductor chip with electrical leads extending from the package which are electrically connected to the semiconductor chip. In a dual in-line package (DIP), the electrical leads are arranged in two parallel rows with the leads depending from the bottom of the housing.
Packaged integrated circuits must undergo a number of different tests, each test requiring the insertion of the integrated circuit package and leads into a test socket. To prevent bending or damage to the leads, zero insertion force (ZIF) sockets have been devised to limit the force exerted on the leads when the package is inserted into a test socket. The most widely known and used ZIF sockets are from 3M Corporation and Aries Corporation. In these sockets the leads of a DIP (dual in-line package) are pinched between two pieces of metal which are, in turn, soldered to a printed circuit board. The metal pieces are held in place by the body of the ZIF socket which is typically made of plastic. The metal pieces are electrically conducting to provide a good electrical path from the DIP lead to the printed circuit board in which the ZIF socket is attached. In all cases, the bodies of these sockets are made of some organic material (plastics or polymers) which can only withstand temperatures as high as 250 degree C. for extended periods of time. The metal used to pinch the leads of the IC DIP packages are beryllium copper alloy or beryllium nickel alloy for a high temperature operation not to exceed 250 degree C. While these sockets perform well within their stated specifications, they cannot be used at temperatures in excess of 250 degree C. because the materials will decompose and fail.
U.S. Pat. No. 6,179,640, assigned to the present assignee, discloses a test socket including two members having planar surfaces arranged to permit relative lateral movement between the two members. One member is a package support and has a plurality of holes extending therethrough for receiving the integrated circuit package leads. Each hole has sufficient size to receive a lead with minimal or no force. The second member is a contact support and has a plurality of contact wires arranged to be in spaced juxtaposition with package leads when a package is inserted into or removed from the support member. The contacts are slidable into engagement with the package leads after the package is inserted.
FIG. 1A
is a plan view of contact support
10
of ZIF socket
8
in accordance with ′640 Patent with spring wires
12
,
14
providing contacts for leads of an integrated circuit package (not shown) which extend through holes
16
,
18
in package support
11
of socket
8
. Wires
12
,
14
are arranged in parallel groups of wire which are anchored to the socket in holes at opposing ends
20
,
21
and
22
,
23
. Vertical separation of the rows of holes
16
and
18
may be 0.3 inch to accommodate an industry standard I.C. package called “narrow DIP”.
FIG. 1B
shows package support
11
slid relative to contact support
10
whereby wires
12
,
14
are moved from holes
16
,
18
and permit the insertion of leads of an integrated circuit package into holes
16
,
18
.
FIGS. 2A
,
2
B represent the same ZIF socket of
FIG. 1
, but now engaged by leads or pins
30
,
31
of UUT
32
. For clarity, the main body of UUT
32
has been removed from
FIG. 2B
to expose the underlying interaction between pins
30
,
31
and spring wires
12
,
14
.
It will be noted that the socket holes
16
,
18
are not located midway between the anchor points of the wires, but rather the length of the wire sections that lie underneath the body of the UUT are significantly shorter than the wire sections that lie outside of the UUT
32
. This causes the shorter inner wire sections to distort more than the longer outer sections.
In order for the spring wire contacts to perform well, a certain amount of reasonable “working distance” must be provided between the anchor points and the contact points. If the working distance is too small, damage to either the UUT pins or the spring wires can result. Experience shows that the smaller the working distance, the more difficult the overall design of the ZIF mechanism, especially in terms of allowing tolerances of the socket components. Consequently, a low working distance can have significant adverse ramifications in terms of both cost and reliability of the final product.
The present invention is directed to increasing the working distance in such a ZIF socket.
BRIEF SUMMARY OF THE INVENTION
In accordance with the invention, wire contacts in a contact support plate of a ZIF test socket are arranged in two parallel partially interdigitated sets to thereby increase the minimum working distance between contact points on the wire and anchor points at either end of the wire. The wires are inclined with respect to the alignment of lead receiving holes in the package support plate to allow for the interdigitation of the sets of wires. Thus the working distance of the wire under the DIP package is not limited to less than half the width of the package.
The invention and objects and features thereof will be more readily apparent from the following detailed description and dependent claims when taken with the drawing.
REFERENCES:
patent: 3932012 (1976-01-01), Reimer et al.
patent: 3993381 (1976-11-01), Horbach
patent: 4090667 (1978-05-01), Crimmins
patent: 4478472 (1984-10-01), Baar
patent: 4583806 (1986-04-01), Tainter, Jr. et al.
patent: 4679886 (1987-07-01), King
patent: 4688870 (1987-08-01), Egawa et al.
patent: 4786256 (1988-11-01), Angeleri et al.
patent: 5021000 (1991-06-01), Scheibner
patent: 5243757 (1993-09-01), Grabbe et al.
patent: 6179640 (2001-01-01), Sikora et al.
patent: 6217341 (2001-04-01), Glick et al.
Beyer Weaver & Thomas LLP
Gilman Alexander
QualiTau, Inc.
LandOfFree
High-temperature minimal (zero) insertion force socket does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High-temperature minimal (zero) insertion force socket, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-temperature minimal (zero) insertion force socket will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3049963