Reduced-pin integrated circuit I/O test

• US 6,397,361 B1
• Filed: 04/02/1999
• Issued: 05/28/2002
• Est. Priority Date: 04/02/1999
• Status: Expired due to Term

• Current Assignee: Twitter Inc (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Saitoh, Toshiharu
• Primary Examiner(s): MOISE, EMMANUEL LIONEL
• Application Number:
  US09/285,911
• Time in Patent Office: 1,152 Days
• Field of Search: 714/724,719,733,734,736 324/73.1,158.1,763,765 326/30,90 327/108,563 365/201,218,230.06 713/1
• US Class Current: 714/724
• CPC Class Codes: G11C 29/02 Detection or location of defective auxiliary circuits, e.g. defective refresh counters
• CPC Class Codes: G11C 29/48 Arrangements in static stores specially adapted for testing by means external to the store, e.g. using direct memory access [DMA] or using auxiliary access paths

Abstract

The present invention provides a method and device for reduced-pin integrated circuit I/O testing. In this regard, the present invention provides for the testing of an integrated circuit or chip in a manner which is independent of the number of test pins present on the testing device. The method and device of the present invention are realized through an integrated circuit having two test ports: a scannable I/O test port and a Forcing-Measuring test port, and a plurality of switches. The scannable I/O test port is employed for the input and output of, among other things, scannable shift-register latch data which affects the states of the plurality of switches in the integrated circuit. The Forcing-Measuring test port is employed for, among other things, forcing or measuring voltages and currents associated with the I/O circuits under test through the switches to the circuits under test. The methods of the present invention are embodied in a plurality of test configurations including: an I/O Short-Circuit test configuration which verifies that each I/O is not short-circuited to a supply voltage or to ground; an I/O Negative and Positive Leakage test configuration; a Pull-Up and Pull-Down Resistor test configuration; Differential I/O test configuration; a Package test configuration; an I/O Driver Least Positive Up Level (LPUL) and Most Positive Down Level (MPDL) test configuration; a single-ended I/O receiver LPUL and MPDL test configuration; a differential I/O receiver LPUL and MPDL test configuration; and Differential I/O Terminator Resistor Test configuration.

Claims

1. A method for testing a chip comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of input/output circuits on the chip;

(b) selectively changing the state of a predetermined number of the plurality of switches from a first state to a second state,

(c) applying a test condition to a predetermined number of the plurality of input/output circuits on the chip through the plurality of switches; and

(d) measuring a resultant condition from the predetermined number of input/output circuits to determine if any of the pre-determined number of input/output circuits on the chip are faulty.

2. The method of claim 1 wherein step (b) comprises the step of inputting switch latch information into an input/output test port on the chip representative of the predetermined number of the plurality of switches to be changed from a first state to a second state.

3. The method of claim 1 wherein step (c) comprises the step of applying a predetermined test voltage to the predetermined number of the plurality of input/output circuits on the chip through the plurality of switches.

4. The method of claim 3 wherein step (d) comprises the step of measuring a resultant current.

5. The method of claim 1 wherein step (c) comprises the step of applying a predetermined test current to the predetermined number of the plurality of input/output circuits on the chip through the plurality of switches.

6. The method of claim 5 wherein step (d) comprises the step of measuring a resultant voltage.

7. A method for performing a short circuit test on input/output circuits on a chip, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of input/output circuits on the chip;

(b) changing the state of a predetermined switch associated with a predetermined input/output circuit on the chip;

(c) applying a predetermined current through the predetermined switch to the predetermined input/output circuit on the chip; and

(d) measuring a resultant voltage through the predetermined switch to determine whether there is a short-circuit in the predetermined input/output circuit on the chip.

8. The method of claim 7 wherein step (b) comprises the step of inputting switch latch information into an input/output test port on the chip representative of the predetermined switch to be changed from a first state to a second state.

9. The method of claim 7 further comprising the step of repeating steps (b)-(d) for every input/output circuit on the chip.

10. A method of performing a negative and positive leakage test on input/output circuits on a chip, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of input/output circuits on the chip;

(b) placing the plurality of switches in a first state;

(c) applying a predetermined voltage through the plurality of switches to the plurality of input/output circuits on the chip; and

(d) measuring a resultant current through the plurality of switches to determine whether there is a positive or negative leakage in the input/output circuits on the chip.

11. The method of claim 10 further comprising the steps of:

(a) if it is determined that there is leakage in the input/output circuits on the chip, placing a predetermined switch associated with a predetermined input/output circuit in a first state, and

(b) placing the remaining plurality of switches in a second state.

12. The method of claim 11 further comprising the step of applying a predetermined voltage through the predetermined switch to the predetermined input/output circuit on the chip.

13. The method of claim 12 further comprising the step of measuring a resultant current through the predetermined switch to determine whether there is any leakage in the predetermined input/output circuit on the chip.

14. The method of claim 13 further comprising the steps of repeatedly:

(a) applying a predetermined voltage through a predetermined switch to a predetermined input/output circuit on the chip; and

(b) measuring a resultant current through the predetermined switch to determine whether there is any leakage in the predetermined input/output circuit on the chip;

until all of the input/output circuits on the chip have been tested for leakage.

15. A method for testing pulling resistors associated with input/output circuits on a chip, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of pulling resistors and input/output circuits on the chip;

(b) selectively changing the state of a predetermined switch associated with a pulling resistor of a predetermined input/output circuit on the chip;

(c) applying a predetermined voltage through the predetermined switch to the pulling resistor of the predetermined input/output circuit on the chip; and

(d) measuring a resultant current through the predetermined switch to determine whether the pulling resistor of the predetermined input/output circuit is faulty.

16. The method of claim 15 wherein step (b) comprises the step of inputting switch latch information into an input/output test port on the chip representative of the predetermined switch to be changed from a first state to a second state.

17. The method of claim 15 further comprising the step of repeating steps (b)-(d) for pulling resistors of every input/output circuit on the chip.

18. A method of performing a functional parametric test on input/output circuits on a chip, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of input/output circuits on the chip;

(b) selectively changing the state of a predetermined switch associated with a predetermined input/output circuit on the chip;

(c) generating a current by turning on a first transistor of a complementary transistor driver stage of the predetermined input/output circuit on the chip;

(d) at least partially turning on a second transistor of the complementary transistor driver stage of the predetermined input/output circuit on the chip; and

(e) measuring a resultant voltage through the predetermined switch to determine whether the functional parametric test of the predetermined input/output circuit on the chip was successful.

19. The method of claim 18 further comprising the steps of:

(a) generating current by turning on the second transistor of the complementary transistor driver stage of the predetermined input/output circuit on the chip; and

(b) at least partially turning on the first transistor of the complementary transistor driver stage of the predetermined input/output circuit on the chip.

20. The method of claim 19 wherein the step of generating current by turning on the second transistor of the complementary transistor driver stage of the predetermined input/output circuit on the chip comprises the step of driving the gate of a PFET transistor to a logic LOW level.

21. The method of claim 18 wherein step (c) comprises the step of driving the gate of an NFET transistor to a logic HI level.

22. The method of claim 18 wherein steps (b), (c), (d), and (e) are performed for each input/output circuit on the chip.

23. The method of claim 22 wherein step (b) comprises the step of inputting switch latch information into an input/output test port on the chip representative of the predetermined switch.

24. The method of claim 22 further comprising the step of repeating steps (b)-(d) for every input/output circuit on the chip.

25. A method for testing differential input/output circuits on a chip, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with a plurality of differential input/output circuits on the chip;

(b) changing the state of a predetermined switch associated with a predetermined differential input/output circuit;

(c) applying a predetermined current through the predetermined switch to the predetermined differential input/output circuit; and

(d) measuring a resultant voltage through the predetermined switch to determine if the predetermined differential input/output circuit is faulty.

26. The method of claim 25 further comprising the step of applying a predetermined voltage through the predetermined switch to the predetermined differential input/output circuit.

27. The method of claim 26 further comprising the step of measuring a resultant current through the predetermined switch to determine if the predetermined differential input/output circuit is faulty.

28. A method for testing an integrated circuit package having a chip die, a plurality of pads on the chip die, and a plurality of pins associated with the plurality of pads, the method comprising the steps of:

(a) providing a plurality of switches on the chip which are associated with the plurality of pads;

(b) changing the state of a predetermined switch associated with a predetermined pad;

(c) applying a predetermined current through the predetermined switch to the predetermined pad; and

(d) measuring a resultant voltage through the predetermined switch to determine if the package is faulty.