Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1997-01-30
2001-01-30
Nguyen, Vinh P. (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S760020
Reexamination Certificate
active
06181146
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a burn-in board used in a burn-in test on a semiconductor product, and particularly to a burn-in board which single makes it possible to perform a burn-in test on plural kinds of semiconductor products which are equal to one another in their package and the number of pins.
2. Prior Art
In order to secure quality and reliability of a semiconductor product, a burn-in test is performed as a kind of screening tests for removing a product having a potential defect. In the burn-in test, a burn-in board is used as a board for accommodating a number of devices to be tested and the burn-in board is accommodated in a burn-in chamber and then the test is performed.
In an existing burn-in board, different kinds of devices to be tested (semiconductor products) which are equal to one another in their package and the number of pins are different in electric test conditions, and therefore, it has been necessary to change over the test circuits and so some additional boards have had to be prepared. As a method for solving such a problem, up to now, a technique is known which has been disclosed in a Japanese laid-open publication Tokkaihei No. 3-170078.
A burn-in board
100
disclosed in this publication has plural (four) IC sockets
102
on a printed wiring board
101
as shown by an external view in
FIG. 8 and a
circuit diagram in FIG.
9
. Each of the IC sockets
102
is provided with fourteen terminals (pins) represented by numbers
1
to
14
, where the terminals of numbers
1
to
6
have the corresponding signals
1
to
6
inputted to them through the respective resistors
103
and the terminals of numbers
8
to
13
have the corresponding signals
8
to
13
inputted to them through the respective resistors
103
. And the terminal of number
14
is connected to a first power source (Vcc)
107
through a circuit changeover socket
104
. The terminal of number
7
is connected to a second power source (the ground potential GND)
108
. The circuit changeover socket
104
can put on and off selectively either one of circuit changeover units
105
a
and
105
b
. The circuit changeover socket
105
a
has resistors
106
and the circuit changeover socket
105
b
has no resistor.
This burn-in board
100
makes it possible to change a circuit (insert or remove the resistors
106
in this example) by wiring a circuit part common to plural kinds of burn-in boards as it is on the single printed wiring board
101
and collecting one-end parts of other circuit wirings than the common part at a part (circuit changeover socket
104
) of the printed wiring board
101
and then putting on or off either one of the circuit changeover units
105
a
and
105
b
which have, respectively, other circuits than the common circuit.
By means of such a composition, the existing burn-in board
100
makes it possible to perform a burn-in test on plural kinds of semiconductor products which are equal to one another in the package and the number of pins.
In the existing burn-in board
100
, however, since one-end parts of other circuit wirings than the common circuit part are collected at a part of the single printed wiring board, wiring length of other circuits than the common circuit on the printed wiring board
101
cannot help being longer when the wiring is drawn from an IC socket
102
more distant from the circuit changeover socket
104
. And there has been a problem that a limit of expansion of a wiring pattern width due to its close pattern increases a signal noise and can have a bad influence upon devices to be tested (semiconductor products).
And some recent products have plural Vcc and GND power sources, where drawing around of the wiring comes to be complicated when collecting one-end parts of other circuit wirings than the common circuit part at a part of the printed wiring board
101
. Moreover, the existing burn-in board
100
has had another problem that manners of change of circuits are greatly limited since only wirings of other circuit parts than the common circuit part can be changed.
SUMMARY OF THE INVENTION
The present invention has been performed in consideration of such problems, and an object of the invention is to provide a burn-in board which can shorten wiring length of other circuit parts than the common circuit part, expand a wiring pattern width, reduce a signal noise, and can diversify manners of change of circuits.
A burn-in board according to the present invention comprises;
a tested device accommodating part which accommodates tested devices each of which has plural terminals, and which has plural test terminals to be electrically connected with the terminals of the tested devices accommodated in it,
a signal supplying means for supplying a signal to test terminals of said tested device accommodating part,
a first electric potential supplying means for supplying a first test electric potential to other test terminals of said tested device accommodating part,
a second electric potential supplying means for supplying a second test electric potential different from the first electric potential to test terminals of said tested device accommodating part, and
a test circuit changeover means which is provided near said tested device accommodating part and which can change a test circuit according to kinds of tested devices by selectively changing over the electric potentials supplied from said first and said second electric potential supplying means to the respective test terminals of said tested device accommodating part.
This burn-in board can change a test circuit by selectively changing over the electric potentials supplied from the first and the second electric potential supplying means to the respective test terminals of the tested device accommodating part according to kinds of tested devices by means of the test circuit changeover means.
A burn-in board as defined in claim
2
is a burn-in board as defined in claim
1
, wherein said test circuit changeover means comprises;
a first circuit changeover socket having plural first receptive terminals electrically connected, respectively, with plural test terminals of the tested device accommodating part and a first electric potential terminal electrically connected with a first electric potential supplying means,
a second circuit changeover socket having plural second receptive terminals electrically connected, respectively, with plural test terminals of the tested device accommodating part and a second electric potential terminal electrically connected with a second electric potential supplying means,
a first circuit changeover unit having plug-in terminals for electrically connecting the first electric potential terminals of the first circuit changeover socket with either receptive terminals corresponding to a test circuit out of the first receptive terminals, and
a second circuit changeover unit having plug-in terminals for electrically connecting the second electric potential terminals of the second circuit changeover socket with either receptive terminals corresponding to a test circuit out of the second receptive terminals.
In this burn-in board, the first electric potential terminals of the first circuit changeover socket are electrically connected with either receptive terminals corresponding to a test circuit out of the first receptive terminals by inserting the plug-in terminals of the first circuit changeover unit into the first receptive terminals and the first electric potential terminals of the first circuit changeover socket. Namely, either receptive terminals corresponding to the test circuit out of the first receptive terminals of the first circuit changeover socket are set at the first electric potential. In such a way, specific terminals out of the plural terminals of a tested device accommodated in the tested device accommodating part are set at the first electric potential. In the same way, the second electric potential terminals of the second circuit changeover socket are electrically connected with either receptive terminals
Holland & Hart LLP
Nguyen Vinh P.
Nippon Steel Semiconductor Corp.
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