JP3603373B2 - Semi-custom IC test circuit - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a semi-custom IC test circuit mechanism that realizes a combination of a plurality of functions by changing a part of a wiring means using a conductive wiring material or a part of a semiconductor element forming means in an IC manufacturing process. About.
[0002]
[Prior art]
Conventional semi-custom ICs include a wiring means using a conductive wiring material on one or more IC chips or a semiconductor element forming means in an IC manufacturing process as a means for selecting a function. By changing the glass mask used in the same process above, the combination of all the functions of the semi-custom IC formed on the actual chip and the completion of the number of combinations of all the functions is completed. The body was being tested.
[0003]
For this reason, when the number of functions of the semi-custom IC increases, in order to confirm whether all conditions of the selected combination of functions can be realized, all combinations of functions are manufactured on a trial basis to confirm the functions, By performing electrical operation confirmation, it is confirmed that all of the combinations of functions satisfy the required specifications of the IC.
[0004]
Further, as the functions of the semi-custom IC increase, the combination of selected functions tends to increase in proportion to the number of functions. The time required to test the characteristics of the combination also increases in proportion to the increase in the function.
[0005]
When the number of functions of the semi-custom IC increases, the combination of selected functions tends to increase in proportion to the number of functions, and the combination of each function is changed to complete the combination according to the function in the manufacturing process. When the body is created and tested, the functions must be controlled due to variations in the characteristics, resistance components, capacitance induction components, wiring materials, insulating films, etc. of the transistors constituting the IC within the range controlled in the manufacturing process. The combination affects the characteristics of the semi-custom IC obtained and adds an uncertain factor to the judgment based on the test result.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to combine the functions of the semi-custom IC with the fixed functions of the completed product when the number of objects to be tested increases due to the increase in the functions of the semi-custom IC. In other words, it is possible to perform a test on any combination of functions of the semi-custom IC for all the completed products by the same procedure and regardless of the combination of functions of the completed products.
[0007]
[Means for Solving the Problems]
The above object is to provide a semi-custom IC that realizes a combination of a plurality of functions by changing a part of a wiring means using a conductive wiring material or a part of a forming means of a semiconductor element in an IC manufacturing process. by one or more test mode switching signal changes the operating state of the circuit to the signal state for performing an operation test of the transfer path (test mode), the one or test mode signal for producing a further test mode A test mode generation circuit to be generated,
The circuit inside the IC, which is generated by the test mode generation circuit, is set to the original state of the circuit inside the IC by the test mode, and the circuit inside the IC is selected from a plurality of functions of the semi-custom IC. Depending on the state of one or more function selection mode detection signals for setting a state for selecting a combination of functions (function selection mode), one of the places for selecting an arbitrary combination from the combination of the plurality of functions Or more function switching signals , a function switching signal generation circuit for generating data of one or more function switching data signals and a function switching signal generation clock signal,
In the manufacturing process, a signal from a physical function switching unit that selects at least one or more function combinations among a plurality of function combinations by a glass mask and a function switching signal generated by the function switching signal generation circuit , A function selection circuit exclusively selected by a test state signal indicating a test state generated by the test mode generation circuit;
This is achieved by switching functions in the test state by a function switching signal input to the function selection circuit.
[0008]
【Example】
An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.
[0009]
FIG. 1 is a block diagram of a function switching circuit of a semi-custom IC for automatic melody playing according to an embodiment of the present invention.
[0010]
By inputting the test mode switching signal 1 to the test mode generating circuit 4, a test mode signal 2 having a code corresponding to the test mode is generated. The test mode signal 2 is input to the test mode detection circuit group 12, and the state shifts to a state for inspecting a signal transmission path inside the IC corresponding to the test mode switching code included in the test mode signal 2.
[0011]
When the test mode switching signal 1 generates a condition preset in the test mode generation circuit 4, the test mode generation circuit 4 outputs the function selection mode detection signal 3. When the function selection mode detection signal 3 is output, the test mode generation circuit 4 returns the state of the test mode signal 2 to the test mode detection circuit group 12 from the test mode to the original signal transmission path of the IC. Is held in a state where the code is transmitted. When the function selection mode detection signal 3 is generated, the test mode generation circuit 4 holds the test mode signal 2 and the function selection mode detection signal 3.
[0012]
When the function selection mode detection signal 3 is generated, the function switching signal generation circuit 7 is activated, and the data of the function switching data signal 5 is selected as an arbitrary function switching code at the timing of the function selection signal generation clock signal 13. To generate a function switching signal 6.
[0013]
When the function selection mode detection signal 3 is input to the function switching circuit 10, if the state of the function selection mode is not detected, the function switching circuit 10 is used in at least one of a plurality of combinations of functions in the manufacturing process. The combination information provided by the physical function switching unit 9 for selecting the combination of the functions by the glass mask is used as the function switching signal 11 to fix the function inside the IC.
[0014]
When the state of the function selection mode is detected by inputting the function selection mode detection signal 3 to the function switching circuit 10, the function switching circuit 10 receives the function switching signal 6 having the function switching code. It is possible to arbitrarily set the function inside the IC using the combination information as the function switching signal 11.
[0015]
FIG. 2 shows a specific logic circuit diagram of FIG. 1, and FIG. 3 shows the timing of each signal in FIG.
[0016]
By inputting the test mode switching signal 1 to the test mode generating circuit 4, the IC is shifted to the test mode, the test mode switching signal 1 is supplied to the one input side of the OR gate 41 as an inverted signal by the inverter 40, and the reset signal 14 From the flip-flop (hereinafter referred to as DF) 42, which has been initialized by the above and is released from the reset state in synchronization with the first rising of the test mode switching signal 1, the DF 42 serving as an input of a 4-bit counter composed of DF 45 The output of the OR gate 41 is applied to the data input D, and the test mode signals 2a to 2d are output in synchronization with the timing of the test mode switching signal 1. The test mode switching signal 1 updates the output of the counter composed of the DFs 42 to 45, and the output of the NAND gate 46 becomes the function selection mode detection signal 3 at the timing when all the test mode signals 2a to 2d become "1". When "0" is generated, the function selection mode is set. Since the output signal of the NAND gate 46 is inverted and transmitted to the input side of the OR gate 41 to which the output of the inverter 40 is not connected by the inverter 47, all the test mode signals 2a to 2d become "1". The output of the NAND gate 46 is inverted by the inverter 47, and the output of the OR gate 41 becomes "1". The state of the clock signal from the DFs 42 to 45 is fixed, and the state of the function selection mode detection signal 3 which is the output of the NAND gate 46 is output. Is fixed to “0”.
[0017]
If at least one of the test mode signals 2a to 2d is in a state of "0", the output of the NAND gate 46 is in a state of "1", and the output of the NAND gate 46 is inverted by the inverter 47 and the OR gate 41 is inverted. However, since the output of the inverter 47 is "0", the output state does not change and the DFs 42 to 45 receive the clock signal and update the test mode signals 2a to 2d.
[0018]
The function selection mode detection signal 3 is inverted by the inverter 77 and becomes a reset signal of the shift register 8 composed of DF70 to DF76 of the function switching signal generation circuit 7 in the function selection mode in which the function selection mode detection signal 3 becomes "0". The reset from DF70 to DF76 is released. When the reset is released by the function selection mode detection signal 3, the shift register 8 waits for data input, and selects the data of the function switching data signal 5 as an arbitrary function switching code at the timing of the function selection signal generation clock signal 13. Thus, data of the function switching signal 6 is generated. The function selection mode detection signal 3 is input to the function switching circuit 10 and is connected to the input terminal of the AND gate 102 connected to the output of the physical function switching unit 9 which is not connected to the output of the physical function switching unit 9. The function selection mode detection signal 3 is input, and a signal obtained by inverting the function selection mode detection signal 3 by the inverter 100 is input to an input terminal of the AND gate 101 to which the function switching signal 6 is connected, to which the function switching signal 6 is not connected. The input terminal which is exclusively selected by inputting, is input to the internal function selection circuit 15 as the function setting signal 11 by the OR gate 103 and is not connected to the signal line A of the AND gate 150 of the internal function selection circuit 15 And the function setting signal 11 is input to the input terminal of the inverter 153 and the function is inverted by the inverter 153. By connecting the constant signal 11 to an input terminal of the AND gate 151 to which the signal line B is not connected, the signal line A or the signal line B is fixed as a signal line in the manufacturing process by the physical function switching unit 9. Are exclusively selected and output from the OR gate 152.
[0019]
When the function selection mode detection signal 3 is "1", the physical function switching section 9 is selected, and the AND gate 150 side of the internal function selection circuit 15 is selected as the function selection signal 11, and the signal line A is OR gated. 152 is output. When the function selection mode detection signal 3 is “0”, the AND gate 101 is selected by the function selection mode detection signal 3 inverted by the inverter 100, and the function switching signal 6 becomes the function selection signal 11 of the internal function selection circuit 15. The AND gate 150 and the AND gate 151 are arbitrarily connected to the AND gate 150 by a code generated by inputting the function switching data 5 and the function switching signal generation clock signal 13 to the shift register 8 of the function switching signal generation circuit 7. The signal line A and the signal line B connected to the AND gate 151 can be output from the OR gate 152.
[0020]
As a result, a test using not only the combination of functions of the semi-custom IC but also the combination of functions fixed in the manufacturing process of the IC, but also the combination of arbitrary functions by the function switching data 5 and the function switching signal generation clock signal 13 in the function selection mode. Is possible.
[0021]
In the first embodiment, when the number of functions increases and the number of combinations increases, the number of flip-flops and the like used for the shift register increases. Since the generation of the code corresponding to the mode becomes complicated, the additional storage type ROM is replaced with the part of the function switching signal generation circuit 7 or the part of the test mode generation circuit 4 to generate and test the combination code of the functions. It is possible to easily generate a code corresponding to the mode.
[0022]
【The invention's effect】
As described above, according to the present invention, a plurality of functions of a semi-custom IC are generated in a function selection mode by a signal generated by a test mode generation circuit, and are determined on a manufacturing basis by a function switching circuit. It is possible to generate an arbitrary combination of the above functions and operate the circuit inside the IC.
[0023]
Due to this, it is fixed to only one of the combinations of a plurality of functions determined in the manufacturing process of the semi-custom IC, so that wiring or elements on the IC by the conductive material for all the combinations of functions are fixed. Reduce the test production period of multiple times to achieve the combination of functions required to guarantee all of the above production conditions,
Reduce the number of tests for functional inspection to confirm the function of the finished product made by the test manufacturing,
This has the effect of eliminating a decrease in the accuracy of function combination due to an uncertain element in the inspection data due to a variation in the required specification characteristics of the IC due to a difference in element characteristics due to the manufacturing environment of the test product in the plurality of times.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is an equivalent circuit diagram of a function switching circuit of the semi-custom IC for automatic melody playing according to the embodiment of FIG. 1;
FIG. 3 is a timing diagram for the circuit of FIG.
[Explanation of symbols]
1 Test mode switching signal 2 Test mode signals 2a, 2b, 2c, 2d Test mode switching signal 3 Function selection mode detection signal 4 Test mode generation circuits 40, 47, 77, 100, 153 Inverters 41, 103, 152 OR gate 42, 43, 44, 45 Flip-flop 46 NAND gate 5 Function switching data signal 6 Function switching signal 6a, 6b, 6c, 6d, 6e, 6f, 6g Function switching signal 7 Function switching signal generating circuits 70, 71, 72, 73, 74 , 75, 76 Flip-flop 8 Shift register 9 Physical function switching unit 10 based on data arrangement on glass mask Function switching circuits 101, 102, 150, 151 AND gate 11 Function setting signal 12 Test mode detection circuit group 13 Function switching Signal generation clock signal 14 Reset signal 15 Internal function selection circuit

Claims (1)

In a semi-custom IC that realizes a combination of a plurality of functions by changing a part of a wiring means using a conductive wiring material or a part of a semiconductor element forming means in an IC manufacturing process,
By one or more test mode switching signal changes the operating state of the circuit within the IC to the test mode, a test mode generating circuit at which to generate the one or test mode signal for producing a further test mode,
Depending on the state of one or more function selection mode detection signals, which are generated by the test mode generation circuit and cause the circuit inside the IC to enter the function selection mode according to the test mode, any combination of the plurality of functions can be selected. one or more functional switching signal at selecting a combination, the function switching signal generator circuit for generating the one or more functional switching data signal data and functionality switching signal generated clock signal,
In the manufacturing process, a signal from a physical function switching unit that selects at least one or more function combinations among a plurality of function combinations by a glass mask and a function switching signal generated by the function switching signal generation circuit , A function selection circuit exclusively selected by a test state signal indicating a test state generated by the test mode generation circuit;
A semi-custom IC test circuit, wherein the function is switched by a function switching signal input to the function selection circuit in the test state.

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