JPH1090360A - Short/open inspection apparatus for terminals at lsi - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a short/open inspection apparatus by which the function of all terminals at an LSI can be checked, by which an inspection process is simplified and whose inspection accuracy is enhanced. SOLUTION: By data used to generate a clock and various signals which are sent from a personal computer 11, a shift register 41 turns on or off three- state output buffers 32a, 32b through switching circuits 61, 63, it sets the input/ output mode of a terminal A or a terminal B, and it supplies a high-level signal or low-level signal to the terminal A or the terminal B through a switching circuit 62 or 64. The shift register 41 controls analog switches 31a, 31b so as to be turned on and off, and it connects a check terminal 5 to the terminal A or the terminal B. The personal computer 11 judges the existence of the short circuit between the terminal A and the terminal B on the basis of a signal which is input from the check terminal 5. As a result, the installation number of lands which are used to send data to the terminals A, B from the outside can be reduced, and the function of all terminals can be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI terminal short / open inspection apparatus for inspecting an LSI terminal for short circuit and open circuit for connecting an LSI to wiring on a substrate.

[0002]

2. Description of the Related Art Conventionally, this type of terminal provided in an LSI has a short circuit because solder is placed between connection wirings between terminals, or a solder for connecting a terminal and a wiring on a substrate floats. Or, it may be open because the connection wiring is broken. Therefore, an open / short inspection of the terminal on such an LSI substrate is required. This is conventionally performed by a visual inspection, an inspection using image processing, and an inspection using a function checker. I have.

[0003] Among the conventional inspection methods, the visual inspection has a limit in the accuracy of human attention, which is limited. Inspection using image processing reduces the reflectance due to uneven lighting,
There is a problem that the accuracy cannot be increased so much due to the relationship between the visual field and the resolution, and there is a problem that it takes a long time to perform the image processing.

In the visual inspection and the inspection using the image processing, the inspection using the function checker is performed because of low accuracy. However, a bet nail for inputting / outputting an inspection signal to all terminals is brought into contact. It is necessary to provide a land to make it work. However, with the increase in the number of terminals and the high-density mounting of the LSI, it has become very difficult to provide lands for contacting bet nails for inputting the signals to all terminals. Not only does it take much time and effort to create inspection software because of the large number of terminals, but it also takes time to perform inspection using a function checker.

[0005] Therefore, in the open / short inspection of the multi-terminal LSI terminals, a visual inspection, an image processing inspection, an inspection using a function checker, and the like are combined to make a bet nail contact with all terminals. Inspections that do not require lands are performed, but this includes inspection methods with low accuracy, so there is a limit to overall improvement in accuracy, and a combination of a plurality of different inspection methods is performed. Therefore, there is a problem that the inspection process becomes complicated and takes time.

[0006]

As described above, the conventional LS
According to the short / open inspection method of the I terminal, the inspection process is complicated and time-consuming because the inspection is performed using three types of inspections: a visual inspection, an inspection using image processing, and an inspection using a function checker. In addition, there is a problem that there is a limit to the improvement of the overall accuracy because the above-mentioned problem and an inspection method with low accuracy are included. Moreover, since lands for contacting the bet nail with all the terminals of the multi-terminal LSI are not provided, it is difficult to perform the inspection with the most accurate function checker on all the terminals. There was also.

Accordingly, the present invention has been made to solve the above-described problems, and a function check test can be performed on all terminals of an LSI regardless of the number of terminals, thereby reducing the time required for the test process. It is an object of the present invention to provide an LSI terminal short / open inspection device that can be simplified and improve inspection accuracy.

[0008]

According to the first aspect of the present invention, an LS
A mode switching means for switching any one of a plurality of terminals for connecting I and an external wiring to an input mode or an output mode; and a mode switching means for applying a voltage to a terminal switched to the input mode by the mode switching means. Output means for outputting an output signal, a switch means for electrically connecting / disconnecting the terminal switched to the input mode and the output means, and generating and supplying a switching control signal for the mode switching means and the switching means. And a signal supply unit for generating and supplying a high-level or low-level signal to a terminal switched to the output mode by the mode switching unit, and providing the signal supply unit with the signal. While supplying data and a clock for operating this signal generating means, the mode switching means switches to an input mode. A controller for inputting a signal input to a connected terminal through the switch means and the output means, and performing a short / open inspection process of the terminal based on the input signal, outside the LSI. Have.

With this configuration, one of the plurality of terminals is set to the output mode by the mode switching means, the other terminal adjacent thereto is set to the input mode, and then the input mode terminal is set to the switch means. And the signal supply means supplies a signal to the output mode terminal. At this time, the controller short-circuits / opens the terminal based on the level of the signal input from the output means. To inspect.

According to a second aspect of the present invention, there is provided mode switching means for switching an arbitrary one of a plurality of terminals for connecting an LSI and an external wiring to an input mode or an output mode, and provided in the LSI. A terminal fixed to an output mode constituting at least a part of the plurality of terminals, an output unit outputting a signal applied to a terminal switched to an input mode by the mode switching unit, and the mode switching unit Switch means for electrically connecting / disconnecting the terminal switched to the input mode and the output means,
A switching control signal for controlling the operation of the mode switching means and the switch means is generated and supplied, and a high level or a low level is applied to a terminal switched to an output mode or a terminal fixed to the output mode by the mode switching means. A signal supply means for generating and supplying a signal;
And data for generating the signal and a clock for operating the signal generating means are supplied to the signal generating means, and input to a terminal switched to an input mode by the mode switching means. A controller that inputs a signal through the switch means and the output means and performs a short / open inspection process on the terminal based on the input signal is provided outside the LSI.

With such a configuration, after one of the plurality of terminals is set to the output mode by the mode switching means and the other terminal adjacent thereto is set to the input mode, the input mode terminal is set to the switch means. Then, a signal is supplied to the terminal in the output mode or the terminal fixed in the output mode by the signal supply means, and at this time, the controller adjusts the level of the signal input from the output means. Then, the short / open of the terminal is inspected.

According to a third aspect of the present invention, there is provided a configuration including test signal input means for inputting a test signal for setting the mode switching means, the switch means, and the signal generation means in an operation mode from outside the LSI. .

With such a configuration, a test signal is externally input to the LSI by the input means, whereby the LSI enters a testable mode.

According to a fourth aspect of the present invention, the controller has a configuration for displaying a result of the inspection process.

With this configuration, the inspector sees the inspection result and knows whether or not the LSI terminal has a short / open.

According to a fifth aspect of the present invention, the controller comprises:
A configuration is provided that includes a personal computer that generates the data and the clock and performs a short / open inspection process of a terminal for connecting the LSI to an external wiring.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of an LSI short / open inspection apparatus according to the present invention. Reference numeral 1 denotes a controller for supplying data and a shift clock for operating the board inspection circuit of the LSI 60, and includes a personal computer 11, an A / D converter 12
And a parallel-serial converter 13. Reference numeral 2 denotes a random logic circuit for performing the original function operation of the LSI 60, and reference numerals 3a and 3b denote bidirectional buffers, and analog switches 31a and 31b and three-state output buffers 32a and 32.
b, terminals A and B for connection to normal buffers 33a and 33b and wiring on the substrate. Reference numeral 4 denotes a control circuit for a board inspection function, which includes a shift register 41 for creating inspection data signals to be supplied to the switch circuits 62 and 64 and the analog switches 31a and 31b, and a decoder 42 for decoding an output signal of the shift register 41. doing.

Reference numerals 62 and 64 denote switch circuits for outputting a high-level or low-level test signal to the three-state output buffers 32a and 32b of the bidirectional buffers 3a and 3b in the test mode. Reference numerals 61 and 63 denote three-state output buffers 32a. , 32b, a switch circuit for supplying a test signal for turning on and off, an analog signal inputted from a terminal A or a terminal B to detect an open signal of a terminal due to a short circuit, unsoldering, etc. , A data terminal for inputting data from the controller 1, a clock terminal 72 for inputting a shift clock from the controller 1 to the control circuit 4, and a 73 for setting the LSI 60 in the board inspection mode. This is a test terminal for inputting high-level signals. In made to the substrate inspection mode. Reference numeral 74 denotes an output terminal for monitoring the data input from the data terminal 71 to confirm that the control circuit 4 is operating normally. Here, the short / open inspection device of the LSI 60 is the remaining part except the random logic circuit 2 in FIG. 1 and is mounted on the LSI 60.

The switch circuit 61 and the three-state output buffer 32a, the switch circuit 63 and the three-state output buffer 32b each constitute mode switching means, the analog switches 31a and 31b constitute switching means, and the shift register 41 comprises It constitutes a supply means. The test terminal 73 constitutes a test signal input unit. or,
The personal computer 11 has a display for display.

Next, the operation of this embodiment will be described. First, adjacent terminals A and B of one LSI 60
The inspection operation for detecting a short circuit will be described with reference to FIG. By setting the LSI 60 to the test mode by inputting a high-level signal to the test terminal 73 of the LSI 60, the shift register 41 is enabled and the switch circuits 61 to 64 are switched to the terminal b. Thereafter, the controller 1 performs the following control to determine whether or not the terminals A and B are short-circuited.

The inspector sets the personal computer 11 of the controller 1 to a mode for inspecting the presence or absence of a short circuit between the terminals A and B of one LSI 60. The personal computer 11 outputs data corresponding to the set mode and a shift clock for operating the shift register 41 to the parallel-serial converter 13. As a result, the serialized data and the shift clock are output from the parallel-serial converter 13 to the data terminal 71 and the clock terminal 72 of the LSI 60.

First, the shift register 41 supplies a high-level signal to the OEA of the switch circuit 61 of the LSI 60 in the first step,
a, the switch circuit 62 and the terminal A
To set the terminal A to the output mode, supply a high-level signal to DATA-A of the switch circuit 62, and output the high-level signal to the terminal A from the three-state output buffer 32a. At the same time, L
A low-level signal is supplied to the OEB of the switch circuit 63 of the SI 60, the three-state output buffer 32b is turned off, the switch circuit 64 and the terminal B are disconnected, and the terminal B is set to the input mode. Further, at this time, the analog switch 31
The high-level SW0 is supplied to the terminal b, the analog switch 31b is turned on, and the input signal of the terminal B is output to the check terminal 5.

Thereafter, the A / D converter 1 of the controller 1
2 converts the signal output from the check terminal 5 into a digital signal by the A / D converter 12 and inputs the digital signal to the personal computer 11. The personal computer 11 is an LSI
DATA-A (high-level signal) output from the 60 shift register 41 to the switch circuit 62, that is, the LSI
The signal output to the terminal A 60 and the signal input from the check terminal 5 are compared, and it is determined whether or not both match at a high level, and the determination result is stored.

Next, in a second step, the shift register 41 supplies a low-level signal to the OEB of the switch circuit 62, and outputs a low-level signal to the terminal A from the three-state output buffer 32a. Then, the controller 1
The personal computer 11 converts the signal output from the check terminal 5 into a digital signal by the A / D converter 12 and inputs the digital signal. The personal computer 11 compares DATA-A (low level) output to the switch circuit 62, that is, the signal output to the terminal A, with the signal input from the check terminal 5, and determines whether or not both match at the low level. judge.

The personal computer 11 short-circuits the terminals A and B only when the signal output to the terminal A in both the first step and the second step matches the signal returned from the check terminal 5. Is determined, and the determination result is displayed on the screen.

Next, an inspection operation for detecting a short circuit between the adjacent terminals A and B of the two LSIs 601 and 602 will be described with reference to FIG. However, the LSIs 601 and 602 are the same as the LSI 60. LSI 601
A high-level signal is input to each test terminal 73 of the LSI 602 to set the respective LSIs 601 and 602 to the test mode to make the shift registers 41 of both the LSIs 601 and 602 operable. 64 is switched to the terminal b side. Thereafter, the controller 1 performs the following control to determine whether there is a short circuit between the terminals A and B.

The examiner connects the personal computer 11 of the controller 1 to the terminals A connected to each other and the terminals B connected to each other.
In this mode, the presence or absence of a short circuit between the terminals A and B of the LSIs 601 and 602 is set. The personal computer 11 stores data corresponding to the set mode and the shift register 4 of each of the LSIs 601 and 602.
1 is output to the parallel-serial converters 131 and 132.

Thus, the parallel-serial converter 13
From 1 the serialized data and clock are LS
It is output to the data terminal 71 and the clock terminal 72 of I601, and at the same time. The serialized data and the serialized clock are output from the parallel-serial converter 132 to the data terminal 71 and the clock terminal 72 of the LSI 602.

The shift register 41 of the LSI 602 has L
A high-level signal is supplied to the OEA of the switch circuit 61 of the SI 602, and a high-level signal is supplied to the OEB of the switch circuit 63.
The 2a and 3 state output buffers 32b are turned on, and the terminals A2 and B2 are set to the output mode.

Next, the shift register 41 of the LSI 602
Sends a high-level signal to DATA-A of the switch circuit 62 of the LSI 602 and the DATA-B of the switch circuit 64.
Are supplied with low-level signals. At this time, the three-state output buffer 32a and the three-state output buffer 3
Since 2b is on, a high-level signal is output to the terminal A2 and a low-level signal is output to the terminal B2.

Next, the shift register 41 of the LSI 601
Supplies a low-level signal to the OEA of the switch circuit 61 of the LSI 601 and the OEB of the switch circuit 63, and
By turning off the state output buffer 32a and the three-state output buffer 32b, the terminal A1 and the terminal B
Set 1 to input mode. At the same time, the shift register 41 supplies a high-level signal to the SWO of the analog switch 31a of the LSI
a is turned on, a low-level signal is supplied to SW1 of the analog switch 31b, and this switch 31b is turned off. As a result, the signal at the terminal A1 of the LSI 601 is output to the check terminal 5 through the analog switch 31a.

The personal computer 11 of the controller 1 converts the output signal of the check terminal 5 into an A / D converter 121
By converting to a digital signal and inputting it, LSI
The voltage of terminal A of 601 is measured, and the measurement result is stored.

Next, the shift register 41 of the LSI 601
Supplies a low-level signal to SW0 of the analog switch 31a of the LSI 601,
a is turned off, and a high-level signal is supplied to SW1 of the analog switch 31b to turn on the analog switch 31b. As a result, the signal at the terminal B1 of the LSI 601 is output to the check terminal 5 through the analog switch 31b.

The personal computer 11 of the controller 1 converts the output signal of the check terminal 5 into an A / D converter 121.
By converting to a digital signal and inputting it, LSI
The voltage of terminal B of 601 is measured, and the measurement result is stored. Next, the personal computer 11 is the LSI 601
Comparing the measured voltages of the terminal A and the terminal B. If the signal of the terminal A is at a high level and the signal of the terminal B is at a low level, it is determined that there is no short circuit. Are the same level, it is determined that there is a short circuit.

Next, an inspection operation for detecting the open state of the adjacent terminals A and B of two LSIs will be described with reference to FIG. The inspector sets the personal computer 11 of the controller 1 to a mode of inspecting the presence or absence of the wiring between the terminals A and the terminals B of the two LSIs 601 and 602 to which the terminals A and the terminals B are connected. The personal computer 11 outputs data corresponding to the set mode and a shift clock for operating the shift register 41 of each of the LSIs 601 and 602 to the parallel-serial converters 131 and 132. As a result, the serialized data and the shift clock are output from the parallel / serial converter 131 as L.
The data is output to the data terminal 71 and the clock terminal 72 of the SI 601, and at the same time, the serialized data and the serialized shift clock are output from the parallel-serial converter 132 to the data terminal 71 and the clock terminal 7 of the LSI 602.
2 is output.

The shift register 41 of the LSI 602 is LS
By supplying a high-level signal to the OEA of the switch circuit 61 of I602 and turning on the three-state output buffer 32a to connect the switch circuit 62 and the terminal A2,
The terminal A2 is set to the output mode. The shift register 41 of the LSI 602 sets DATA-A of the switch circuit 62 to a high level signal and outputs this signal to the terminal A2 through the three-state output buffer 32a.

Next, the O of the switch circuit 61 of the LSI 601 is
A low-level signal is supplied to the EA to turn off the three-state output buffer 32a, thereby setting the terminal A1 to the input mode. The shift register 41 of the LSI 601 supplies a high-level signal to the SWO of the analog switch 31a to turn on the analog switch 31a, and outputs the signal input to the terminal A1 to the check terminal 5 through the analog switch 31a.

Next, the personal computer 11 of the controller 1 outputs the output signal of the check terminal 5 to the A / D converter 1
By converting the digital signal into a digital signal at 21 and inputting it, the input signal at the terminal A1 is measured, and the measured level is stored.

Next, the shift register 41 of the LSI 602 supplies a low-level signal to DATA-A of the switch circuit 62, and outputs this signal to the terminal A2 through the three-state output buffer 32a. After that, the personal computer 11 outputs the output signal of the check terminal 5 of the LSI 601 to A /
The input level of the terminal A1 is measured by converting the digital signal into a digital signal by the D converter 121 and inputting it. The personal computer 11 sets the terminal A when the DATA-A of the switch circuit 62 of the LSI 602 is set to a high level signal.
1 is at a high level, and D
The terminal A1 when ATA-A is a low level signal
If the measurement result is low, it is determined that there is no open state between the terminals A1 and A2 and around it, but if a measurement result other than the above is obtained, it is determined that there is an open state.

The personal computer 11 determines the presence or absence of an open state between the terminal B1 and the terminal B2 and the vicinity thereof by the same operation as described above.

According to the present embodiment, the LSI 60 (LS
A board inspection circuit for inspecting short / open of terminals A and B of I601 or LSI 602) is built in the same LSI 60, the substrate inspection circuit is operated, and data for an inspection signal is supplied. By providing the controller 1 for performing the short / open inspection of the terminal A and the terminal B outside, even if the LSI 60 is a multi-terminal LSI in which the LSI 60 is mounted at a high density, the number of lands that contact the bed nail can be reduced. . Therefore, even for a multi-terminal LSI mounted at high density, a function check with high inspection accuracy can be easily performed for all terminals. For this reason, it is not necessary to combine inaccurate visual inspection and inspection based on image processing, and the inspection process can be simplified, and quick and appropriate inspection can be performed.
Further, since the control circuit 4 for inspection is mounted on the LSI 60, the inspection program of the personal computer 11 can be simplified even if the LSI is mounted with many terminals and high density. There is an advantage.

In the above-described embodiment, the bidirectional buffers 3a and 3b with the analog switches 31a and 31b are used. However, if these buffers are used only as output terminals in the normal mode, they are shown in FIG. As described above, the unidirectional buffer 3a including the output buffer 32c and the analog switch 31a may be mounted, and the same effect as in the above embodiment can be obtained.

In the above embodiment, the inspection operation of the two adjacent terminals A and B of the LSI 60 has been described. However, even if there are a plurality of these terminals, the inspection can be performed with the same configuration. There is a similar effect.

[0044]

As described above, according to the present invention, LS
By enabling the function check inspection for all the terminals of I regardless of the number of terminals, the inspection process can be simplified and the inspection accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an LSI equipped with an LSI terminal short / open inspection apparatus according to the present invention.

FIG. 2 is a block diagram for explaining a method for inspecting the presence or absence of a short circuit between adjacent terminals of the LSI shown in FIG. 1;

FIG. 3 is a block diagram for explaining a method of checking whether or not the terminals of the two LSIs shown in FIG. 1 are short-circuited;

FIG. 4 is a block diagram for explaining a method of inspecting whether or not the LSI terminal and the land of the substrate shown in FIG. 1 are open;

FIG. 5 is a block diagram showing a configuration example of another LSI in which an LSI terminal short / open inspection device of the present invention is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Controller 2 Random logic circuit 3a, 3b Bidirectional buffer 4 Control circuit 5 Check terminal 11 Personal computer 12, 121, 122 A / D converter 13, 131, 132 Parallel / serial converter 31a, 31b Analog switch 32a, 32b 3 State output buffers 33a, 33b Buffer 41 Shift register 42 Decoder 60, 601, 602 LSI 61, 62, 63, 64 Switch circuit 71 Data terminal 72 Clock terminal 73 Test terminal 74 Output terminal A, A1, A2, B, B1, B2 Terminal

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hayato Shiina 21 Toshiba Communication Technology Co., Ltd. 3-1-1 Asahigaoka, Hino-shi, Tokyo

Claims (5)

[Claims] 1. Mode switching means for switching any one of a plurality of terminals for connecting an LSI and an external wiring to an input mode or an output mode, and switching to an input mode by the mode switching means. An output unit that outputs a signal applied to a terminal that is connected to the terminal; a switch unit that electrically connects and disconnects the terminal that is switched to the input mode with the output unit; and a switching control signal of the mode switching unit or the switching unit. And a signal supply means for generating and supplying a high-level or low-level signal to a terminal switched to an output mode by the mode switching means.
I, data for generating the signal and a clock for operating the signal generating means are supplied to the signal generating means, and input to a terminal switched to an input mode by the mode switching means. And a controller for inputting a signal through the switch means and the output means, and performing a short / open check process of the terminal based on the input signal, provided outside the LSI. Open inspection device. 2. A mode switching means for switching any one of a plurality of terminals for connecting an LSI and an external wiring to an input mode or an output mode, and a plurality of terminals provided in the LSI. A terminal fixed to an output mode which constitutes at least a part of the above, output means for outputting a signal applied to a terminal switched to the input mode by the mode switching means, and switching to the input mode by the mode switching means. A switch means for electrically connecting / disconnecting the terminal and the output means, generating and supplying a switching control signal for controlling the operation of the mode switching means and the switch means, and switching to an output mode by the mode switching means. Signal that generates and supplies a high-level or low-level signal to the Said and means LSI
And data for generating the signal and a clock for operating the signal generating means are supplied to the signal generating means, and are input to a terminal switched to an input mode by the mode switching means. A controller for inputting a signal through the switch means and the output means, and performing a short / open check process of the terminal based on the input signal, provided outside the LSI; Open inspection device. 3. A test signal input means for inputting a test signal for setting the mode switching means, the switch means, and the signal generation means to an operation mode from outside the LSI. The LSI terminal short / open inspection device described in the above. 4. The short / open inspection apparatus according to claim 1, wherein the controller displays an inspection processing result. 5. The controller according to claim 1, wherein the controller includes a personal computer that generates the data and the clock, and performs a short / open check process of a terminal for connecting the LSI to an external wiring. 5. The short / open inspection device for an LSI terminal according to any one of 1 to 4.