Semiconductor memory component and method for testing semiconductor memory components having a restricted memory area (partial good memories)

• US 20060250864A1
• Filed: 03/15/2006
• Published: 11/09/2006
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Polaris Innovations Limited (Wi-LAN Inc.)
• Original Assignee: Infineon Technologies AG
• Inventors: Hartmann, Udo
• Granted Patent: US 7,382,669 B2
• Time in Patent Office: Days
• US Class Current: 365/201
• CPC Class Codes: G11C 2029/1806 Address conversion or mapping, i.e. logical to physical address
• CPC Class Codes: G11C 29/18 Address generation devices; Devices for accessing memories, e.g. details of addressing circuits
• CPC Class Codes: G11C 29/38 Response verification devices

Abstract

A semiconductor component and method of testing a semiconductor component is disclosed. The invention relates to the parallel testing of semiconductor memory components having a fully functional memory area, which are classified as all good memory, and of semiconductor memory components having a restricted memory area, which are classified as partial good memory. For testing semiconductor memory components classified as partial good memory, the result, independently of the result of the comparison for those test addresses which are assigned to a memory area outside the functional memory area of the semiconductor memory component classified as partial good memory, is overwritten with an error free signal and a semiconductor memory component classified as all good memory is simulated. The testing of semiconductor memory components classified as partial good memory is accelerated and simplified.

Claims

1. A semiconductor memory component comprising:

a memory cell array, including data word groups having a desired number of memory cells storing data bits;

a test write register for buffer-storing a primary test data word read into the memory cell array at a test address; and

comparator units for comparing mutually corresponding data bits of the respective primary test data word and of a secondary test data word read out from the memory cell array from the test address, in which case, when mutually corresponding data bits in the primary and secondary test data words match, an error free signal is generated in each case on PF signal lines respectively assigned to one of the comparator units,

2. The semiconductor memory component of claim 1, further comprising an error address memory for storing an error address identifying a nonfunctional partial area of the desired address space, and an address comparator for comparing the respective test address with the error address, in which case, when the test address matches the error address, an error free signal is constrained in each case on the PF signal lines.

3. The semiconductor memory component as claimed in claim 1, having a test logic comprising:

a data generator connected to the data lines and serving for generating the primary test data words;

an address counter for generating the test addresses;

a sequence controller, which controls the data generator and the address counter in a test mode of the semiconductor memory component; and

an evaluation unit comprising the test write register and the comparator units.

4. The semiconductor memory component as claimed in claim 1, comprising a compression unit that combines an error information item transmitted on the signal lines on a number of compression signal lines that is less than the number of PF signal lines.

5. The semiconductor memory component of claim 1, comprising erasable I/O skip units respectively assigned to a data line, an I/O skip unit being erased if memory cells assigned to the respective data line are identified as not being functional, and an erased I/O skip unit constraining an error free signal on the corresponding PF signal line.

6. The semiconductor memory component of claim 1, comprising a classification memory element for storing a classification information item for distinguishing semiconductor memory components classified as all good memories, in the case of which the desired address space is functional, from semiconductor memory components classified as partial good memory, in the case of which a partial area of the desired address space is nonfunctional.

7. The semiconductor memory component as claimed in claim 6, comprising wherein the address comparator can be activated by the classification memory element.

8. The semiconductor memory component as claimed in claim 6, comprising wherein the classification memory element is suitable for storing a classification identifier, on the basis of which it is possible to distinguish between semiconductor memory components in the case of which the desired number of data lines is functional and semiconductor memory components in the case of which a portion of the data lines is nonfunctional.

9. The semiconductor memory component as claimed in claim 8, comprising wherein the I/O skip units can be activated by the classification memory element.

10. A semiconductor memory component comprising:

a memory cell array, including data word groups having a desired number of memory cells;

a plurality of data lines connected to a respective one of the memory cells of the data word groups suitable for transmitting data bits stored in the memory cells;

a plurality of internal address lines configured for a desired address space in the memory cell array to be addressed by means of the internal address lines;

a test write register for buffer-storing a primary test data word read into the memory cell array at a test address; and

comparator units for comparing mutually corresponding data bits of the respective primary test data word and of a secondary test data word read out from the memory cell array from the test address, in which case, when mutually corresponding data bits in the primary and secondary test data words match, an error free signal is generated in each case on PF signal lines respectively assigned to one of the comparator units,

further comprising an error address memory for storing an error address identifying a nonfunctional partial area of the desired address space, and an address comparator for comparing the respective test address with the error address, in which case, when the test address matches the error address, an error free signal is constrained in each case on the PF signal lines.

11. The semiconductor memory component as claimed in claim 10, having a test logic comprising:

a data generator connected to the data lines and serving for generating the primary test data words;

an address counter for generating the test addresses;

a sequence controller, which controls the data generator and the address counter in a test mode of the semiconductor memory component; and

an evaluation unit comprising the test write register and the comparator units.

12. The semiconductor memory component as claimed in claim 10, comprising:

a compression unit, that combines an error information item transmitted on the signal lines on a number of compression signal lines that is less than the number of PF signal lines.

13. The semiconductor memory component of claim 10, comprising erasable I/O skip units respectively assigned to a data line, an I/O skip unit being erased if memory cells assigned to the respective data line are identified as not being functional, and an erased I/O skip unit constraining an error free signal on the corresponding PF signal line.

14. The semiconductor memory component of claim 10, comprising a classification memory element for storing a classification information item for distinguishing semiconductor memory components classified as all good memories, in the case of which the desired address space is functional, from semiconductor memory components classified as partial good memory, in the case of which a partial area of the desired address space is nonfunctional.

15. The semiconductor memory component as claimed in claim 14, comprising wherein the address comparator can be activated by the classification memory element.

16. The semiconductor memory component as claimed in claim 14, comprising wherein the classification memory element is suitable for storing a classification identifier, on the basis of which it is possible to distinguish between semiconductor memory components in the case of which the desired number of data lines is functional and semiconductor memory components in the case of which a portion of the data lines is nonfunctional.

17. The semiconductor memory component as claimed in claim 16, comprising wherein the I/O skip units can be activated by the classification memory element.

18. A method for testing semiconductor wafers having semiconductor memory components each having a memory cell array, which in each case has a desired address space predefined by a desired number of addressing lines and a desired I/O area predefined by a desired number of data lines the memory cell arrays being functional to different extents, comprising:

functionally testing the memory cell arrays of the semiconductor memory components in a prefuse memory test;

replacing nonfunctional areas of the memory cell arrays by activating redundant memory cells;

storing an error address identifying an irreparable memory area within the desired address space in an error address memory in semiconductor memory components having a restricted memory area; and

functionally testing the semiconductor memory components in a postfuse memory test by writing in and reading out test data words at test addresses within the desired address space, an error-free behavior of the respective irreparable memory area being simulated in semiconductor memory components having a memory area with restricted functionality when the respective test address matches the error address.

19. The method as claimed in claim 18, comprising wherein during the postfuse memory test, generating the test data words and the test addresses in an internal test logic of the respective semiconductor memory device;

writing the test data words to the memory cell array and are buffer-stored in a test write register; and

reading out the test data words from the memory cell array and comprising bit by bit with the test data words buffer-stored in the test write register, an error free signal being generated on the corresponding signal lines when the compared data bits match, and an error signal being generated when there is no match.

20. The method as claimed in claim 18, comprising wherein marking a further irreparable memory area within the desired I/O area by erasing I/O skip units, assigned in each case to a data line assigned to the further irreparable memory area, in the semiconductor memory components having a restricted memory area, the erased I/O skip units, in the case of semiconductor memory components having a further irreparable memory area, simulating an error-free behavior of data lines assigned to the further nonfunctional memory area.

21. A semiconductor memory component comprising:

a memory cell array, including data word groups having a desired number of memory cells configured to store data bits;

means for buffer-storing a primary test data word read into the memory cell array at a test address; and

comparator means for comparing mutually corresponding data bits of the respective primary test data word and of a secondary test data word read out from the memory cell array from the test address, in which case, when mutually corresponding data bits in the primary and secondary test data words match, an error free signal is generated in each case on PF signal lines respectively assigned to one of the comparator means,

further comprising means for storing an error address identifying a nonfunctional partial area of the desired address space, and an address comparator for comparing the respective test address with the error address, in which case, when the test address matches the error address, an error free signal is constrained in each case on the signal lines.