Test system for testing the quality of semiconductor parts and handling the collection of operation status data on the tester and handlers

A test system testing whether test objects, such as semiconductor parts, are good or bad collects operation status data to increase the operation rate of the tester testing the test objects and the handlers handling the test objects. The relay device to which the handlers and the tester are connected, collect operation status data from them, makes a count of test objects, and sends the data and the count to the server device and the storage device. Based on the collected data and count, the server device calculates the operation time of the handlers and the tester necessary or testing a unit of test objects. The next time the test is made, the handler references the operation time to search for the optimum combination of the handlers and the tester.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a test system including a tester for 
testing the quality of manufactured semiconductor parts and a plurality of 
handlers for carrying semiconductor parts into, or carrying them out from, 
the tester, and more particularly to the collection of operation status 
data on the tester and the handlers. 
2. Prior Art 
Conventionally, a test has been made in an IC or LSI parts factory to see 
if manufactured semiconductor parts satisfy the specified characteristics. 
In this test process, a test system has been used which includes two types 
of components: one is a tester for measuring the characteristics of 
semiconductor parts under a specified test condition (e.g., input voltage, 
ambient temperature, operating frequency) and the other is a handler for 
carrying semiconductor parts into, and carrying them out from, a test 
position so that the tester can test them. To meet the need for testing 
various types of semiconductor parts and for performing various types of 
tests, a variety of testers and handlers are provided. And, depending upon 
the semiconductor part to be tested and test items to be used in the test, 
a specific combination of a tester and handlers is used. 
In general, the tester designed for various semiconductor parts is large; 
it is installed in a fixed location within the factory. By contrast, the 
handler designed for semiconductor parts which is limited, is mobile; a 
handler is selected according to the type of semiconductor parts to be 
tested or the type of test to be performed. When the test system is in 
operation, a plurality of appropriate handlers are connected to the tester 
to measure the characteristics and performance of the semiconductor parts 
to be tested. 
To improve the utilization of the tester and the handler, the system also 
collects their operation data. The next time the same semiconductor part 
is manufactured, collected data is used in selecting the tester and the 
handler best suited for testing the semiconductor part. 
However, to reduce the workload on a worker responsible for collecting 
data, the conventional system has collected data only on the tester which 
most affects the utilization of the test system. In addition, it does not 
collect data on an operation change that occurs within a short period of 
time. This prevents data necessary for the optimum operation of the test 
system from being collected, making it difficult for the tester and 
handler to further increase the operation. 
SUMMARY OF THE INVENTION 
To solve the above mentioned problems, a test system according to the 
present invention collects operation status data from the tester testing a 
test object and the handlers handling the test object so that the tester 
can test the test object, makes a count of test objects, stores the status 
data and the count, and calculates the operation time necessary for the 
tester and handlers for testing a unit of test objects. 
The next time the same type of test object is tested, this system searches 
for a combination of the tester and handlers equivalent in efficiency to a 
combination of the tester and handlers used in the past in testing the 
same type of test object and finds the most suitable combination. This 
results in the test time being less than that spent in the past test, 
ensuring the tester and handler operation efficiency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The following explains an embodiment of a test system according to the 
present invention. 
FIG. 1 is a block diagram of a test system according to the present 
invention. This test system is installed in a factory manufacturing 
semiconductors such as ICs or LSIs and is for use in the final test 
process of test objects. It is composed primarily of a plurality of 
modules for testing test objects and a monitor control module for 
monitoring and controlling the whole system, thus forming a network on the 
whole. 
Each of a plurality of modules 100a-100n includes a device 10A, a bar code 
reader 10B, a relay device 20, a first handler 30A and a second handler 
30B and a tester 40. The device 10A receives data (e.g., test object type, 
lot number, test condition) necessary for performing a test on test 
objects such as ICs or LSIs and displays data received from a relay device 
20. The bar code reader 10B makes data entry easier. The relay device 20 
(operating as a collection means) collects data regarding the test result 
and the operating status of test objects from the handler 30A, hander 
30B,and tester 40. The first hander 30A and the second hander 30B carry 
in, mount, dismount, and carry out test objects so that the tester 40 can 
measure the characteristics of the tester objects. The test 40 measures 
the characteristics of test objects under the specified test condition. 
The monitor control module 200 includes a server device 50A which performs 
the overall monitoring and control of the whole system; a storage device 
50B which contains data entered from the device 10A, test result data on 
test objects sent from the relay device 20, and operating status data on 
the handlers 30A, 30B, and tester 40; a printer 50C which prints 
processing results produced by the server device 50A; a backup server 
device 60A and a backup storage device 60B which act as alternate devices 
for the server device 50A and storage device 50B respectively to ensure 
fault tolerance; and a display device 70 which displays processing results 
sent from the server device 50A or data stored in the storage device 50B. 
FIG. 2 shows the procedure for communication among the devices within a 
module. The relay device 20, the key module in each of modules 100a-100n 
for communication both with the monitor control module 200 and among the 
devices in the module, relays processing instructions, processing results, 
and error data to or from the first handler 30A, second handler 30B, 
tester 40, and device 10A. In addition, the relay device 20 sends or 
receives test result data regarding test objects, operating status data 
regarding the devices within the module, and device monitor and control 
information to or from the monitor control module 200. 
The handler 30A and the handler 30B each have their own identification 
numbers to uniquely identify themselves. The DIP switch or the parallel 
connector in each of the handler 30A and the handler 30B is used to set up 
the identification number. To prevent the identification number of a 
handler from duplicating with that of another, the server device 50A 
manages the correspondence between handlers and identification numbers. 
To allow the relay device 20 to know easily and reliably whether or not the 
handler 30A and/or handler 30B are connected to the relay device 20, a 
parallel-interface-based current loop is used as the interface between the 
relay device 20 and the handler 30A and/or the handler 30B. Although a 
little bit complex, a serial interface implemented through serial 
communication may also be used as the interface. 
To enable the relay device 20 to know the connection status of the handlers 
30A and 30B and, at the same time, their identification numbers, it is 
desirable that parallel connectors be used to set up the identification 
number of the handlers 30 and that a parallel interface be used between 
the relay device 20 and the handlers 30. This configuration allows the 
relay device 20 to check the loopback laid between the relay device 20 and 
each of the connected handlers 30, more specifically, to check which 
terminal is closed (the current is active) or open (the current is not 
active), thus giving the relay device 20 information as to whether or not 
the handlers are connected as well as their identification numbers. 
Conversely, when a connected handler 30 which has been powered on is 
disconnected from the relay device 20 or is powered off and all the 
terminals are open, the relay device 20 knows that the handler 30 is 
disconnected or the power is turned off. 
When the handler 30A or handler 30B is disconnected or when the power is 
off, the operator inputs a reason or a cause in the input/output device 
10A to exactly grasp the operation status for each handler. 
The relay device 20 outputs the connection status information and 
identification numbers, obtained as described above, to the server device 
50A; it also outputs operation information of the handler 30A, handler 
30B, and tester 40 to the server device 50A. 
FIG. 3 shows operation status data of the handlers and the tester. As shown 
in this figure, data of event management numbers, event occurrence 
time-stamps, test object lot numbers, tester/handler identification 
numbers, event contents, and event code numbers is sent from the relay 
device 20 to the server device 50A in real time. Based on the data, the 
server device 50A references identification numbers to identify the 
operating status of each device. The data is stored in the storage device 
50B. 
FIG. 3 does not show the handler operation time and the handler 
non-operation time. However, these two times may be clearly distinguished 
if the server device 50A assigns a period of time, during which the 
handler 30A or the handler 30B is not connected, as the handler 
non-operation time. 
FIG. 4 is a timing chart showing the processing times of test objects. The 
relay device 20 (operating as a collection means) collects information on 
the time during which each of the handler 30A, second handler 30B, and 
tester 40 processes a test object. More specifically, the relay device 20 
receives the operation start trigger pulse and the operation end trigger 
pulse from each of the handler 30A, handler 30b, and tester 40. And, for 
the test object A which is handled by the first handler 30A and the test 
object B (B') which is handled by the second handler 30B, the relay device 
20 (operating as a calculation means) uses the trigger pulse reception 
times to calculate the following three times: the time (t1-t2) during 
which the test object B waits to be tested by the tester 40, the test time 
(t2-t3) during which the test object B is tested by the tester 40, and the 
exchange time (t3-t4) during which the test object B is exchanged with 
some other test object B'. The relay device 20 then sends the calculation 
results to the server device 50A. 
The wait time, test time, and exchange time, described above, allow the 
system to evaluate the operation status of the handler 30A, handler 30B, 
or tester not only for the time during which each device is turned on; 
instead, the system evaluates the operation status using the time during 
which each device actually handles and tests a test object. This method 
gives the system more exact operation status data for the handler 30A, 
handler 30B, and tester 40. 
The relay device 20 also counts the number of test objects while 
calculating the times, and sends the count to the server device 50A. 
As described above, the relay device 20 outputs to the server device 50A 
and the storage device 50B various types of data such as the test result 
and the number of test objects, the connection status (operation status) 
of the handlers 30A and 30B, the wait time, test time, and exchange time 
of the handlers 30A and 30B and tester 40. The server device 50A performs 
calculation on the data stored in the storage device 50B. 
The server device 50A calculates the monthly and weekly operation time 
total for each device, calculates the contents of events for each lot, or 
calculates the total time required to test each unit of test objects. The 
display device 70 accesses the server device 50A to get the calculation 
result and displays it. 
The server device 50A stores into the storage device 50B the test history 
data for the test objects tested in the past. This history data includes 
the operation times required by the handlers 30A and 30B and the tester 40 
to test a unit of test objects for each lot as well as the identification 
numbers of the handlers 30A and 30B and tester 40 used in the test. When 
the same type of test object is tested, the system refers to the test 
history data to search for the best combination of the handlers 30A and 
30B and the tester 40, or for the best combination of the handlers 30C and 
30D and the tester 40' (not shown in the figure), for testing the object. 
This reduces the operation time required by the handler 30A and the tester 
40 to test a unit of test objects, thus enabling the same type of test to 
be completed in less time. 
The relay device 20 (operating as a computation means) not only measures 
the characteristics of test objects but also counts the numbers of good 
test objects and bad test objects. More specifically, it counts the number 
of good test objects, bad test objects, re-tested test objects, and the 
total number of test objects. The relay device 20 outputs these numbers to 
the server device 50A and the storage device 50B. 
The number of bad test objects includes not only bad test objects but also 
those objects which are bad because of faulty tools, such as faulty IC 
sockets or probes, on the handlers 30A and 30B and tester 40. Therefore, 
if the bad object ratio is higher than a pre-defined ratio (predefined by 
the server device 50A operating as a setting means), a re-test must be 
made to identify the real cause. To determine whether to make a re-test, 
the server device 50A (operating as a determination means) uses the 
numbers received from the relay device 20 and a ratio pre-defined for each 
test object type or for each test object lot. The server device 50A 
compares the bad object ratio received from the relay device 20 with a 
pre-defined ratio, making it possible to determine whether to make a test, 
precisely and speedily. 
Note that, when the re-test must be made, the system reads the test 
condition information from the storage device 50B (operating as 
accumulation means) instead of the user re-inputting the test condition in 
the input/output device 10A. This eliminates cumbersome data re-input and 
sets up the re-test condition smoothly and correctly. 
The above mentioned tools on the handlers 30 and tester 40 may cause 
electrical contact problems or mechanical malfunctions after long use. To 
reduce the number of test objects determined as bad because of aged tools, 
it is desirable that long-used tools be exchanged before problems develop. 
For this purpose, the handlers 30 and tester 40 collect tool usage length 
and tool usage count data, and the relay device 20 sends tool type data as 
well as collected tool usage length and tool usage count data to the 
server device 50A and storage device 50B. 
The storage device 50B contains specification data on the tool types and 
their maximum usage length and count and, upon receiving collected data 
from the relay device 20, updates tool usage length and count history 
data. The server device 50A (operating as acquisition means and judgement 
means) compares the specification data with the history data, both 
contained in the storage device 50B, and determines whether or not each 
tool is still usable. If the server device 50A determines that a tool can 
no longer be used, it sends information indicating the condition to the 
input/output device 10A and the display device 70 and suspends the 
processing until the user judges the condition. 
In this way, the server device 50A compares tool durability specification 
data with tool usage history data to determine if the tool is still 
usable, allowing the user to make a correct decision. As a result, this 
prevents a tool exceeding the maximum tool usage length or count from 
being used. 
When the handlers 30 and the tester 40 re-test a test object, they collect 
the tool usage length and count data again. Therefore, data collected 
during the re-test, which may also be used in determining whether the tool 
is usable, helps make a correct judgment.