Electrical connectors – With coupling movement-actuating means or retaining means in... – Retaining means
Reexamination Certificate
2001-02-07
2003-04-22
Feild, Lynn D. (Department: 2839)
Electrical connectors
With coupling movement-actuating means or retaining means in...
Retaining means
Reexamination Certificate
active
06551122
ABSTRACT:
This invention relates generally to automatic test equipment. More particularly, this invention relates to a device for mechanically attaching automatic test equipment with machinery that positions semiconductor devices for testing.
BACKGROUND OF THE INVENTION
Semiconductor manufacturers generally test semiconductor devices at various stages of production. During manufacturing, integrated circuits are fabricated in large quantities on a single silicon wafer. The wafer is cut into individual integrated circuits called dies. Each die is loaded into a frame, and bonding wires are attached to connect the die to leads that extend from the frame. The loaded frame is then encapsulated in plastic or another packaging material to produce a finished product.
Manufacturers have a strong economic incentive to detect and discard faulty components as early as possible in the manufacturing process. Accordingly, many semiconductor manufacturers test integrated circuits at the wafer level, before a wafer is cut into dies. Defective circuits are marked and generally discarded prior to packaging, thus saving the cost of packaging defective dies. As a final check, many manufacturers test each finished product before it is shipped.
To rapidly test large quantities of semiconductor components, manufacturers commonly use automatic test equipment (“ATE” or “testers”). In response to instructions in a test program, a tester automatically generates input signals to be applied to an integrated circuit, and monitors output signals. The tester compares the output signals with expected responses to determine whether the device under test, or “DUT,” is defective. Because testers are highly automated, they can run millions of tests in only a few seconds.
Customarily, component testers are designed in two different portions. A first portion, called a “test head,” includes circuitry that is preferably located close to the DUT, for example, driving circuitry, receiving circuitry, and other circuitry for which short electrical paths are essential. A second portion, called a “tester body,” is connected to the test head via cables, and contains electronics that are not required to be close to the DUT.
Special machines move and electrically connect devices to a tester in rapid succession. A “prober” is used to move devices at the semiconductor wafer level. A “handler” is used to move devices at the packaged device level. Probers, handlers, and other devices for positioning a DUT relative to a tester are generically known as “peripherals.” Peripherals generally include a site where DUTs are positioned for testing. The peripheral rapidly feeds a DUT to the test site, the tester tests the DUT, and the peripheral moves the DuT away from the test site, so that another DUT can be tested.
The test head and peripheral are separate pieces of machinery that generally have separate support structures. Therefore, before testing can begin it is necessary for the test head and the peripheral to be attached together. In general, this is accomplished by moving the test head toward the peripheral, carefully aligning the test head, and latching the test head to the peripheral. Once latched, a docking mechanism pulls the test head and peripheral together, causing spring-loaded contacts between the test head and peripheral to compress and form electrical connections between the tester and the DUT. This process of aligning and attaching the test head to the peripheral is commonly known as “docking.”
FIG. 1
illustrates a conventional mechanism for docking a test head to a peripheral. The docking mechanism of
FIG. 1
is customarily used in conjunction with the Catalyst™ test system, provided by Teradyne, Inc. of Boston, Mass. As shown in
FIG. 1
, a docking mechanism
100
is attached to a receptacle
112
. Several docking mechanisms
100
are generally attached to the outside of a test head near the top of the test head. Several receptacles are generally attached to a peripheral, in complementary locations that allow the docking mechanisms
100
to mate with the receptacles
112
. The docking mechanism
100
and receptacle
112
of
FIG. 1
are shown in a fully docked configuration, i.e., in the configuration they assume for electronically testing devices.
As shown in
FIG. 1
, the docking mechanism
100
includes a latch barrel
110
and a latchpin
118
that runs axially within the latch barrel
110
. Four ball bearings
116
are positioned within holes in the latch barrel
110
, around the circumference of the latchpin
118
. The outer entrances to the holes are slightly deformed from perfect circles (not visible in the figure). The deformed regions form a barrier that prevents the ball bearings
116
from falling out of the latch barrel
110
.
The latchpin
118
has different portions
118
a
and
118
b
along its length, and the different portions have different diameters. To effect latching and unlatching, the latchpin
118
advances and retracts with respect to the latch barrel
110
. As the latchpin
118
moves, the portion of the latchpin that
118
makes contact with the ball bearings
116
changes. As a result, the radial positions of the ball bearings
116
change. For example, when the portion
118
a
of the latchpin with a relatively large diameter aligns with the ball bearings
116
, the ball bearings extend outwardly from the center of the latch barrel
110
, increasing the effective circumference of the latch barrel
110
. When the portion
118
b
of the latchpin
118
with a relatively small diameter aligns with the ball bearings
116
, the ball bearings are free to collapse inwardly, reducing the effective circumference of the latch barrel
110
.
The receptacle
112
includes a washer
114
having an inner diameter just slightly larger than the outer diameter of the latch barrel
110
with the ball bearings
116
fully retracted. Depending upon the position of the latchpin
118
relative to the latch barrel
110
, the ball bearings
116
either prevent the washer
114
and latch barrel
110
from separating, or allow the washer
114
to freely slide off and on the latch barrel
110
.
An actuator
120
establishes the position of the latchpin
118
. The latchpin
118
has a threaded portion (not visible) that extends into the actuator
120
. The actuator
120
includes a nut (not visible) that has a fixed position relative to the actuator
120
and engages the threaded portion of the latchpin
118
. The latchpin can be rotated under control of a motor and gears (not visible) that reside within the actuator
120
. Depending upon the direction of rotation, the latchpin
118
either advances or retracts relative to the actuator
120
.
FIGS. 2A-C
illustrate various configurations that the docking mechanism
100
assumes during normal use.
FIG. 2A
shows the docking mechanism
100
in a “ready-to-latch” configuration—prior to the latch barrel
110
being inserted into the receptacle
112
. The latchpin
118
is fully retracted. A spring (not shown) exerts an upward force
216
on the latch barrel
110
(base region
220
) relative to the latchpin
118
, so that the a tab
210
extending from the latchpin
118
rests against a lower inside shoulder
214
b
of the latch barrel
110
. The first portion
118
a
of the latchpin with the relatively large diameter rests against the ball bearings
116
, and the ball bearings
116
partially protrude through the holes in the latch barrel
110
.
FIG. 2B
shows the docking mechanism
100
at the instant that the latch barrel
110
is inserted into the receptacle
112
(not shown). As the latch barrel
110
is inserted into the receptacle
112
, the washer
114
catches the ball bearings
116
and exerts a downward force on them. The latch barrel
110
is then pushed downwardly, and the ball bearings
116
are moved into contact with the relatively narrow portion
118
b
of the latchpin
118
. The ball bearings collapse inwardly, and the latch barrel
110
enters through the washer
114
of the receptacle
112
. Once the ball bearings
116
clear the washer
114
, the latch barrel
Bosy Brian J.
Lewinnek David W.
Dinh Phuong K T
Feild Lynn D.
Rubenstein Bruce D.
Teradyne, Inc.
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