1. Field of the Invention
The present invention relates to an IC testing apparatus for testing a semiconductor device constructed by a semiconductor integrated circuit (hereinafter referred to as IC), such as, for example, a memory IC or a logic IC.
2. Description of Related Art
FIG. 3 shows a schematic configuration of an example of a conventional IC testing apparatus. An IC testing apparatus comprises, mainly, an IC tester 100 which generates a test pattern signal to be applied to an IC under test, an address signal, a control signal, an expected value signal and the like, and determines whether an IC under test is defectless (pass or conforming article) or defective (failure or non-conforming article) based on a response output signal read out from the IC under test, and a handler (semiconductor device transporting and handling apparatus) 400 which transports ICs to be tested from a loader section to a test section to make an electrical contact between an IC under test and an IC socket, and carries, when the test is completed, the tested IC out of the test section to an unloader section where the tested ICs are sorted out or classified on the basis of the test results.
The IC tester 100 includes a test head 200 which is a separate body electrically connected to the main body of the IC tester via a cable KB1. In the exemplary IC testing apparatus, this test head 200 is disposed in the predetermined position under the test section of the handler 400. The test head 200 usually includes a driver group for applying a test pattern signal and/or an address signal generated by the IC tester 100 to an IC under test, and a comparator group for comparing a response output signal read out from the IC under test with an expected value signal. An output signal from the comparator group is sent to the IC tester 100 via the cable KB1.
On the upper portion of the test head 200 is detachably mounted a member or fixture 300 called a measurement part which electrically connects a group of drivers and a group of comparators in the test head to IC sockets SK to which lead terminals of the IC under test are electrically contacted (hereinafter simply referred to as a measurement part). A predetermined number of IC sockets are mounted on the upper surface of the measurement part 300, which is disposed in the test section of the handler 400.
The handler 400 makes, after transporting the IC under test to its test section, the IC under test contact with the IC socket SK and the IC tester 100 applies a predetermined test pattern signal to the IC under test through the cable KB1, the test head 200, the measurement part 300 and the IC socket SK to perform the test of the IC under test. The tested IC is removed from the IC socket by the handler 400 and then transported from the test section to the unloader section.
The IC tester 100 operates in accordance with a test program stored in a main controller 101 and tests the IC under test via the IC socket mounted on the measurement part 300. That is, a test pattern signal is applied to the IC under test from the IC tester 100 via the cable KB1, the test head 200, and the measurement part 300. The response signal from the IC under test is acquired by the test head 200 via the measurement part 300, and the response signal is compared with an expected value signal supplied from the IC tester 100 by the comparator group disposed within the test head 200, then the comparison result is transmitted to the IC tester 100 via the cable KB1. The IC tester 100 performs a determination operation to identify the failure position of the IC under test or the like based on the result of the comparison between the response signal and the expected value signal.
Next, the reason why the measurement part 300 is detachably mounted on the test head 200 will be explained.
There are many kinds of ICs under test. Therefore, when ICs each having pins the number of which is different from that of another IC are tested, a measurement part 300 must be replaced by another measurement part 300 on which an IC socket adaptable to the specific IC under test is mounted.
In addition, since the number of pins of an IC varies from several tens to several hundreds depending on the IC kind, the number of ICs which can be tested at the same time, i.e., the number of ICs which can be tested simultaneously (hereinafter referred to as the number of simultaneous tests) largely varies. Specifically explaining, the number of channels through which test pattern signals or power supply voltages, device control signals and the like can be supplied to an IC under test from the IC tester 100 is about 1000 in general, 1024 in specific. Some of the 1024 channels of the signal paths are appropriately allocated to each IC socket SK to perform the test. Therefore, when ICs each having a small number of pins are tested, the number of simultaneous tests can be large, but when ICs each having several hundred pins are tested, the number of simultaneous tests is obliged to become small.
For the above reason, a plurality of measurement parts 300 on each of which IC sockets of one kind in terms of the number of pins are mounted are provided. One of those measurement parts 300 is mounted on the test head 200 in accordance with the kind (the specifications) of the IC under test so that the test of different kinds of ICs can be performed.
FIGS. 4 to 10 show examples of various types of measurement parts. FIGS. 4A, 4B and 4C are plan view diagrams each showing a construction of a measurement part 300 called type No. 5 (TYPE=5). Further, in each drawing of FIGS. 4 to 10, a square area in the measurement part 300 shown by a dotted line indicates a mounting position of an IC socket SK, and a numeral in the square area indicates a number affixed to each IC socket SK (also corresponds to a number affixed to an IC under test to be contacted with the IC socket).
FIG. 4A shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 32 (SUM=32) and the IC sockets are arranged in 4 rows.times.8 columns (hereinafter expressed as 4.times.8). FIG. 4B shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 16 (SUM=16) and the IC sockets are arranged in 4 rows.times.4 columns (4.times.4). FIG. 4C shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 4 rows.times.2 columns (4.times.2). Further, in FIGS. 4B and 4C, a portion to which 0 is affixed indicates a position having no IC socket. The common characteristics of the measurement parts 300 of TYPE-5 shown in FIGS. 4A, 4B and 4C are that the IC sockets SK are disposed in all of the 4 rows and the numbers of the IC sockets are indexed in the horizontal direction.
On the contrary, FIGS. 5A, 5B and 5C are plan view diagrams each showing a construction of measurement part 300 called type No. 4 (TYPE=4). FIG. 5A shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 32 (SUM=32) and the IC sockets are arranged in 4 rows.times.8 columns (4.times.8). FIG. 5B shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 16 (SUM=16) and the IC sockets are arranged in 4 rows.times.4 columns (4.times.4). FIG. 5C shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 4 rows.times.2 columns (4.times.2). The characteristic of the measurement part of TYPE=4 different from that of the measurement part of TYPE=5 shown in FIG. 4 is that in the measurement part of TYPE=4, the numbers of the IC sockets are indexed in the vertical direction. Further, the number allocation of the IC sockets is determined based on the preference of each user and there is no technical difference between the numbering methods.
FIG. 6 is a plan view diagram showing a construction of measurement part 300 called type No. 3 (TYPE=3). The measurement part 300 of TYPE=3 is one in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 2 rows.times.4 columns (2.times.4). The characteristic of the measurement part 300 of TYPE=3 is that the mounting positions and the indexed numbers of the IC sockets SK are arranged in cross-stitch arrangement. Only one kind of this type as shown in FIG. 6 is available.
FIGS. 7A, 7B and 7C are plan view diagrams each showing a construction of a measurement part 300 called type No. 2 (TYPE=2). FIG. 7A shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 16 (SUM=16) and the IC sockets are arranged in 2 rows.times.8 columns (2.times.8). FIG. 7B shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 2 rows.times.4 columns (2.times.4). FIG. 7C shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 4 (SUM=4) and the IC sockets are arranged in 2 rows.times.2 columns (2.times.2). In the measurement part 300 of TYPE=2, the numbers of the IC sockets SK are all indexed in the horizontal direction.
FIGS. 8A, 8B and 8C are plan view diagrams each showing a construction of a measurement part 300 called type No. 1 (TYPE=1). FIG. 8A shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 16 (SUM=16) and the IC sockets are arranged in 2 rows.times.8 columns (2.times.8). FIG. 8B shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 2 rows.times.4 columns (2.times.4). FIG. 5C shows a measurement part 300 in which the number of simultaneous tests SUM is equal to 4 (SUM=4) and the IC sockets are arranged in 2 rows.times.2 columns (2.times.2). In the measurement part 300 of TYPE=1, the numbers of the IC sockets SK are all indexed in the vertical direction.
FIGS. 9 and 10 show examples of special measurement parts. FIG. 9 is a plan view diagram showing a construction of a measurement part 300 called type No. 6 (TYPE=6). The measurement part 300 of TYPE=6 is one in which the number of simultaneous tests SUM is equal to 8 (SUM=8) and the IC sockets are arranged in 1 row (1.times.8).
FIG. 10 is a plan view diagram showing a construction of a measurement part 300 called type No. 7 (TYPE=7). The measurement part 300 of TYPE=7 is one in which the number of simultaneous tests SUM is equal to 16 (SUM=16) and the IC sockets are arranged in 2 rows (2.times.8).
As described above, there are provided various types of measurement parts 300, and one of those types of measurement parts is selected correspondingly to ICs under test. The selected measurement part is mounted on the test head 200 to perform the test of the ICs under test.
Incidentally, there are following preparation items to be performed prior to the start of a test for ICs under test.
(1) A measurement part 300 on which IC sockets SK corresponding in number to pins of an IC under test have been mounted is selected and mounted on the test head 200.
(2) A test program is loaded in the main controller 10 of the IC tester 100 (see FIG. 3), said test program having such function that it indexes a number to each of ICs under test in accordance with the type of the mounted measurement part 300, thereby to identify each IC under test.
(3) In order for the handler 400 to perform the operation for transporting ICs under test to the IC sockets SK in accordance with the type of the mounted measurement part 300, an arrangement type 4.times.8, 4.times.4, 4.times.2, . . . or the like is set in a setting device 401 of the handler 400.
After the preparation work described above is completed, the test of the ICs under test is performed. However, since a conventional system does not have means to make sure which type of the measurement part 300 is mounted on the test head 200, an operator must certainly perform, when the measurement part 300 is replaced by another one, the operation of the item (2) for the IC tester 100, and the operation of the item (3) for the handler 400.
If the operator fails to perform those operations, the test is not normally performed and in the worst case, IC supplying means of the handler 400 and/or the IC sockets SK mounted on the measurement part 300 and the like are damaged. Moreover, there is a problem that a serious accident such as a misclassification occurs, due to an erroneous recognition of the number of an IC socket SK, during the classification operation of the tested ICs at the unloader section based on the test results.