JPS636471A - Logic integrated circuit - Google Patents

Abstract

PURPOSE:To shorten a system-down time and to simplify inspection facilities at device level by installing a judging circuit part in a semiconductor logic integrated circuit and checking a function circuit part whenever necessary. CONSTITUTION:When a specific signal is inputted to an input terminal part A, the function circuit part 3 performs prescribed operation to output a prescribed signal to an output terminal B. An input switching circuit part 2 selects a signal from the input terminal part A or the signal from the judging circuit part 6 and an output switching part 4 connects the output signal of the function circuit part 3 by selecting the judging circuit part 6 or switching circuit part 5. All signals necessary for inspection are stored in the judging circuit part 6 and a judgement is made with an external control signal, so that if the circuit is defective, that is reported to the outside.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to semiconductor logic integrated circuits (hereinafter referred to as LSr),
In particular, the present invention relates to a semiconductor logic integrated circuit having a configuration that enables failure diagnosis of circuits configured therein.

[Conventional technology 1] Conventional LSIs are used mounted on printed wiring boards, but even if one of the LSIs fails, the effect is large and in most cases leads to system failure, so individual LSIs are required to have higher reliability than necessary. Moreover, the failure diagnosis requires a large amount of man-hours even if expensive equipment and highly skilled inspectors are used.

[Problems to be solved by the invention] When a so-called electronic circuit package is constructed by mounting a large number of conventional LSIs on a board with printed wiring, even if one LSI fails, the entire device will go down. , Since the failure diagnosis requires a large amount of man-hours, it takes a long time to restore the entire device and the number of times it is repaired is also large.Furthermore, it takes a lot of man-hours to completely inspect the package in the intermediate process. It is true that the situation is approaching the point where it is almost impossible to do so, both in terms of testing technology.

An object of the present invention is to provide a logic integrated circuit that enables highly reliable package inspection.

[Means for Solving the Problems] The present invention has at least one circuit section input terminal and one circuit section output terminal in one semiconductor chip, and when a predetermined signal is input to the input terminal, a predetermined signal is output. a functional circuit section that performs an operation and outputs a predetermined signal to the output terminal; input terminal sections whose number is the same as the number of input terminals of the functional circuit section; and output terminal sections whose number is the same as the number of output terminals of the functional circuit section. , an input switching circuit section that exists between the input terminal section and the functional circuit section and selects either a signal from the input terminal section or a signal from the determination circuit section described below; and a stage subsequent to the functional circuit section. an output switching circuit unit located at the output switching circuit unit, which selects and connects the output signal of the functional circuit unit to either a judgment circuit unit (described later) or a switching circuit unit (described later); and inspects the operation quality of the functional circuit unit. All necessary input signals and the corresponding correct output signals of the functional circuit are stored internally in advance, and the input switching circuit and the output switching circuit are switched by an external control signal. The input signals that have been accumulated are sequentially applied to the function circuit section, and the corresponding output signals are read in order and compared with the correct output signals that have been accumulated, and if the results are good. For example, the input switching circuit section and the output switching circuit section are operated to connect the input terminal section, the functional circuit section, and the output terminal section so that the circuit can be used as a logic integrated circuit having a specific function; If not, a determination circuit section having a function of operating a switching circuit section to be described later to set all output terminals of the output terminal section to high impedance and informing the outside through a terminal section to be described later that the chip is unusable; A switching circuit section that is located between the switching circuit section and the output terminal section and puts all output signals to the output terminal section into a high impedance state according to a signal from the judgment circuit section, and a terminal section that connects the judgment circuit section and the outside. This is a logic integrated circuit characterized by having the following features.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, a semiconductor logic integrated circuit (L
SI>1 indicates that the output of the functional circuit section 3 is outputted from the input terminal section A, the input switching circuit section 2, the functional circuit section 3, the output switching circuit section 4, the switching circuit section 5, the judgment circuit section 6, etc. It consists of an output terminal section B that informs the user that the LSll is unusable, and a terminal section C that indicates that the LSll is unusable. Input switching circuit section 2. Although the output switching circuit section 4 and the switching circuit section 5 are actually composed of a plurality of electronic switch circuits, they are shown here in the form of simple switches for the sake of simplicity.

The functional circuit section 3 performs a predetermined operation when a predetermined signal is input to the input terminal section A, and outputs a predetermined signal to the output terminal section B. The input switching circuit section 2 selects either the signal from the input terminal section A or the signal from the determination circuit section 6.

The output switching circuit section 4 selects and connects the output signal of the functional circuit section 3 to either the judgment circuit section 6 or the switching circuit section 5.

The judgment circuit section 6 stores in advance both all the input signals necessary for inspecting the operation quality of the functional circuit section 3 and the correct output signals of the functional circuit section 3 corresponding thereto. The input switching circuit section 2 and the output switching circuit section 4 are operated by an external control signal to sequentially apply the accumulated input signals to the functional circuit section 3, and each corresponding output signal is sequentially applied to the functional circuit section 3. Compare the read and stored correct output signals, and if the result is good, operate the input switching circuit section 2 and the output switching circuit section 4 to switch the input terminal section A, the functional circuit section 3, and the output terminal section. B is connected to make the chip usable as a logic integrated circuit with a specific function, and if not, the switching circuit section 5 is operated to set the output terminal of the output terminal section B to high impedance. It has a function of notifying the outside through the terminal section C that it is unusable. The switching circuit section 5 puts all the output signals to the output terminal section B into a high impedance state in response to the signal from the determination circuit section 6.

In FIG. 1, when a signal is normally applied to the input terminal section A from the outside, the signal is applied to the input switching circuit section 2 through the conductive path 7, and finally to the functional circuit section 3 through the conductive path 8. Ru. The functional circuit section 3 generates an output signal corresponding to the input signal, and outputs it to the outside through the route of the conductive path 9 → output switching circuit section 4 → conductive path 10 → switching circuit section 5 → conductive path 11 → output terminal section B. . Normally, the LSI of the present invention is used in the state shown in FIG.

FIG. 2 is a diagram showing the state when diagnosing LSI 1.

First, a diagnosis start signal is applied from the outside to the judgment circuit section 6 through the terminal section C using the control line 18.

The judgment circuit section 6 uses control lines 14 and 15 to connect the input switching circuit sections 2 to 2, respectively. By inverting each switch of the output switching circuit section 4, the judgment circuit section 6 → conductive path 12 → input switching circuit section 2 → conductive path 8 → functional circuit section 3 → conductive path 9 → output switching circuit section 4 → conductive path 13 → A conductive path for the determination circuit section 6 is formed.

Next, the judgment circuit section 6 uses this conductive path to
The input cover pattern to be inspected for quality is sent out, and the corresponding output cover pattern is read. The read pattern is sequentially compared with the correct output pattern for the input pattern, which is stored in the judgment circuit 6 in advance, to judge whether it is good or bad.

If the result is good, a good signal is sent to the outside through the sense line 17→terminal section C, and at the same time, the control line 14.
15 to set the switches of the input/output switching circuit sections 2 and 4 as shown in FIG. If the result is negative, the output of the switching circuit section 5 is set to a high impedance state using the signal on the control line 16, and the sense line 17→terminal C
Notify the outside of the negative status through the This situation is shown in Figure 3.

In this way, LSI has increased the number of terminals by a very small number (terminal part C
(-equivalent) allows complete diagnosis.

FIG. 4 shows a case in which a plurality of such LSIs are mounted on a printed wiring board to form an electronic circuit package (hereinafter referred to as package) 100 having an algorithm.

In the figure, S and T are input/output terminals, 50-52.60-62
10 to 12 are LSIs of the present invention, 40 to 42 are outputs connected to the control line 18 in FIG. 1, and 20 to 22.3
0 to 32 are signal lines connected to the sense line 17 in FIG. Further, in this diagram, actual input/output signal lines are omitted for simplicity.

In FIG. 4, driver circuits 70 and 71 are connected to the tip of the signal line 90 of the input terminal S, and each output of the driver circuits 70 and 71 is 10 to 12 degrees.
0 to 42 are used to start the judgment circuits built in each LSI 50 to 52 and 60 to 62 to execute diagnostic work, and the respective results are sent to the AND circuit 72 using signal lines 20 to 22 and 30 to 32. If the output 80 is outputted to the output terminal T, it becomes possible to judge whether the package 100 is normal or not by monitoring the output 80 from the system side by passing it under the terminal.

Even if a large number of such electronic circuit packages are used, the above-described method allows the system to instantly determine which package is defective, thereby greatly reducing system down time.

In addition, each L
Since the SI has a built-in judgment circuit, there is no need to apply a huge test pattern to check all the algorithms of the electronic circuit package as in the past, and the signal 90 in Fig. 4 can be applied. It is only necessary to monitor output 80, and if a certain LSI is defective, monitor output 20.
-22. A defective LSI can be instantly identified by checking only 30-32.

If package inspection is carried out based on this concept, only inspection equipment for the purpose of detecting defects that occur during manufacturing will be sufficient for package inspection, and the number of equipment and inspectors can be significantly reduced. .

[Effects of the Invention] As explained above, the present invention has a determination circuit section installed inside a semiconductor logic integrated circuit, so that it is possible to check the functional circuit section whenever necessary. It is easier than conventional methods, such as reducing system down time, simplifying the inspection method, which is currently the biggest bottleneck in package inspection, simplifying inspection equipment, lowering costs, and shortening failure diagnosis time. This has the effect of enabling more reliable package inspection.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG.
FIG. 3 is an explanatory diagram of the operation, and FIG. 4 is a diagram showing an electronic circuit package in which a plurality of LSIs shown in FIG. 1 are mounted. 1... Semiconductor logic integrated circuit of the present invention 2... Input switching circuit section 3... Functional circuit section 4... Output switching circuit section 5
...Switching circuit section 6...Judgment circuit section A...
Input terminal section B...Output terminal section C...Terminal section

Claims (1)

[Claims] (1) One semiconductor chip has at least one circuit input terminal and one circuit output terminal, and when a predetermined signal is input to the input terminal, a predetermined operation is performed to output a predetermined signal to the output terminal. A functional circuit section that outputs a signal, an input terminal section whose number is the same as the number of input terminals of the functional circuit section, an output terminal section whose number is the same as the number of output terminals of the functional circuit section, an input terminal section and the functional circuit section. an input switching circuit section that is located between the input terminal section and selects either a signal from the input terminal section or a signal from the determination circuit section (to be described later); an output switching circuit section to which either the judgment circuit section (described later) or the switching circuit section (described later) is selected and connected; and all input signals necessary to test the operation quality of the functional circuit section and their corresponding input signals. The input switching circuit section and the output switching circuit section are operated by controlling the input switching circuit section and the output switching circuit section by an external control signal, and store both the correct output signal of the functional circuit section internally in advance. The signals are sequentially applied to the functional circuit section, and each corresponding output signal is read in order and compared with the accumulated correct output signal. If the result is good, the input switching circuit section and the output switching circuit section are and the input terminal section,
The functional circuit section and the output terminal section are connected to make it usable as a logic integrated circuit having a specific function, and if not, the switching circuit section described later is operated to output the output from the output terminal section. A judgment circuit section which makes all the terminals high impedance and notifies the outside through the terminal section (to be described later) that the chip is unusable, and a judgment circuit section located between the output switching circuit section and the output terminal section, which outputs a signal from the judgment circuit section. A logic integrated circuit comprising: a switching circuit section that puts all output signals to a terminal section into a high impedance state; a judgment circuit section; and a terminal section that connects an external device.