Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
2002-01-14
2004-05-25
Le, Dieu-Minh (Department: 2114)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C714S718000
Reexamination Certificate
active
06742144
ABSTRACT:
BACKGROUND OF INVENTION
This invention relates to elevated-temperature electronic-test systems, and more particularly to robotic testers for memory modules including SIMMs and DIMMs.
A variety of electronic systems including personal computers (PCs) use DRAM memory chips mounted on small, removable memory modules. Older single-inline memory modules (SIMMs) have been replaced with dual-inline memory modules (DIMMs), and 184-pin RIMMs (Rambus inline memory modules) and 184-pin DDR (double data rate) DIMMs. New kinds of memory modules continue to be introduced.
The memory-module industry is quite cost sensitive. Testing costs are significant, especially for higher-density modules. Specialized, high-speed electronic test equipment is expensive, and the greater number of memory cells on high-speed memory modules increases the time spent on the tester, increasing test costs.
Handlers for integrated circuits (ICs) have been used for many years in the semiconductor industry. Handlers accept a stack of IC chips that are fed, one at a time, to the tester. The tested IC is then sorted into a bin for IC chips that have passed or failed the test. Handlers have also been developed for memory modules.
Rather than use an expensive general-purpose I.C. tester, inexpensive testers based on PC motherboards have been developed. These motherboard-based testers cost only about $10 K while replacing a quarter-million-dollar I.C. tester. The memory module to be tested is inserted into a test socket on a test adapter board (daughter card) mounted on the back-side of the motherboard. Special handlers can be used for module insertion.
Elevated-temperature testing is often desired to more thoroughly screen for defects. Hot air can be blown onto the memory module being tested. Ideally, the motherboard itself is cooled while the memory module under test is heated. See the parent application, “Connector Assembly for Testing Memory Modules from the Solder-Side of a PC Motherboard with Forced Hot Air”, U.S. Ser. No. 09/702,017, now U.S. Pat. No. 6,357,023.
FIG. 1
highlights funneling hot air to the memory module being tested, while the motherboard inside a chassis is cooled. A conventional PC motherboard is mounted upside-down within chassis
60
. Rather than connect motherboard substrate
30
directly to chassis
60
, as in a conventional PC, motherboard substrate
30
is mounted to metal plate
64
by standoffs or spacers
61
. Motherboard substrate
30
is not mounted directly to chassis
60
in this embodiment, although it could be in some embodiments. Screws, bolts, or clamps (not shown) can be used to secure metal plate
64
to chassis
60
.
Test adapter board
50
is mounted to well
66
, while well
66
is mounted to metal plate
64
. Test socket
51
is mounted to test adapter board
50
, while pins
52
provide electrical connection from test socket
51
to motherboard substrate
30
. The memory module
18
being tested is inserted into test socket
51
. Test adaptor board
50
provides electrical connection from the module-under-test (MUT) in the SIMM/DIMM test socket
51
to the leads for the removed SIMM socket on the PC motherboard.
Motherboard substrate
30
has components
42
,
44
(I.C. chips, sockets, capacitors, etc.) mounted on component-side
32
of substrate
30
. Memory modules
36
are SIMM or DIMM modules that fit into SIMM/DIMM sockets
38
. SIMM/DIMM sockets
38
(hereinafter SIMM sockets
38
) have metal pins that fit through holes in substrate
30
. Expansion cards
46
are plugged into expansion sockets that are also mounted onto component-side
32
of substrate
30
. Cables
48
and expansion cards
46
are bulky but do not interfere with a robotic arm inserting memory module
18
into test socket
51
since cables
48
and expansion cards
46
are mounted below substrate
30
, while test socket
51
is mounted above substrate
30
. Cables
48
and expansion cards
46
are kept out of the way inside chassis
60
.
Test adapter board
50
is a small circuit board that allows an automated handler, a person, or a robotic arm easy access to SIMM/DIMM test socket
51
that is mounted on test adaptor board
50
. Test socket
51
on one surface of test adapter board
50
mates with connectors on SIMM/DIMM memory module
18
, the module-under test. The other surface of adaptor board
50
has adapter pins
52
inserted in holes to make electrical contact. These adaptor pins are soldered into through-holes in adaptor board
50
and in substrate
30
. Adapter pins
52
are arranged to have the same arrangement and spacing as the substrate-mounting pins for SIMM sockets
38
. One or more of SIMM sockets
38
has been removed from the component side of the PC motherboard, leaving the through-holes. Adapter pins
52
are then fitted through the exposed through holes for the removed SIMM socket. Rather than push the pins through from component-side
32
, adapter pins
52
are pushed through from solder-side
34
to component-side
32
.
Top plate
75
can be mounted to chassis
60
in a variety of ways, such as by standoffs or metal guides or brackets. Top plate
75
has an opening to allow access to test socket
51
so that a robotic arm can insert and remove memory module
18
from test socket
51
.
When environmental testing is desired, heated air is forced between top plate
75
and metal plate
64
. This heated air blows past memory module
18
when it is inserted into test socket
51
. The heated air warms memory module
18
to an elevated temperature. When memory module
18
is heated, it is typically more likely to fail than when at room temperature. Such elevated-temperature testing provides a margin or guard-band to the test, so that the passing memory modules are more reliable than modules tested at room temperature.
Cooling fan
71
is provided in chassis
60
to cool motherboard substrate
30
and its components
42
,
44
and expansion cards
46
. Even air at room temperature can be effective at cooling the motherboard if a sufficient volume of air is blown past the motherboard's components. Components such as integrated circuits heat up during operation and benefit from such cooling. Of course, reduced-temperature air could also be blown into chassis
60
, such as air from outside a building in a cold climate.
Since metal plate
64
separates motherboard substrate
30
from test adapter board
50
, the cooling air from cooling fan
71
is separated from the heated air blown against memory module
18
under test. Test adapter board
50
is mounted within well
66
and forms a sufficient seal to prevent the cooling air within chassis
60
from cooling memory module
18
being heated and tested.
Top plate
75
can be replaced with a tube, rectangular pipe, or air guide that blows hot air directly on memory module
18
. This may provide a more efficient air flow. Temperature sensors such as thermocouples could be added near the test socket. Chassis
60
can be provided with slots, holes and openings to allow for air flow to motherboard components
42
,
44
and expansion cards
46
. Multiple cooling fans can be used.
A larger chassis with multiple openings on the top, each for holding a metal plate
64
with a motherboard and test adapter board can be used. This allows for parallel testing using several motherboards and test sockets.
FIG. 2
is an overhead diagram looking down on a multi-motherboard test station with overhead rails for an x-y-z robotic handler. See the parent application, Automated Multi-PC-Motherboard Memory-Module Test System with Robotic Handler and In-Transit Visual Inspection, U.S. Ser. No. 09/660,714. Operator
100
can sit in front of the test station, controlling operation with a touch-screen or keyboard. Trays of untested memory modules can include a barcode that is scanned in to main system interface
65
by operator
100
before the tray is put into input stacker
63
. Robotic handler
80
then picks untested modules that are moved over to input tray
62
by stacker
63
. The modules are first inserted into leakage tester
82
. Modules that pass are
Auvinen Stuart T.
Kingston Technology Co.
Le Dieu-Minh
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