Device and method for compensating defect in semiconductor memory

• US 7,020,003 B2
• Filed: 06/21/2004
• Issued: 03/28/2006
• Est. Priority Date: 02/11/2004
• Status: Active Grant

• Current Assignee: Winbond Electronics Corporation
• Original Assignee: Winbond Electronics Corporation
• Inventors: Yeh, Jun-Lin
• Primary Examiner(s): Tran, Andrew Q.
• Assistant Examiner(s): Le, Toan
• Application Number:
  US10/710,123
• Publication Number:
  US 20050174827A1
• Time in Patent Office: 645 Days
• Field of Search: 365/120, 365/230.06, 365/500, 365/230.08, 365/189.05
• US Class Current: 365/120
• CPC Class Codes: G11C 29/88 with partially good memories
• CPC Class Codes: G11C 29/883 using a single defective memory device with reduced capacity, e.g. half capacity

Abstract

A device for compensating a semiconductor memory defect suitable for a semiconductor memory is provided. The device comprises: a memory array, the memory array having a memory region consisting of a plurality of memory cells, the memory array being coupled to the address decoder circuit and the sensing circuit for storing data, if the memory array has a defect, the memory array is divided into a plurality of sub-memory regions, wherein one of the plurality of sub-memory regions is defectless, the memory array is replaced by the defectless sub-memory regions for storing data. A selection circuit coupled to the control unit, selects one of the memory region and the defectless sub-memory region to store data. A first input address buffer coupled to the control unit and the address decoder circuit has an address input port and an address output port. The address input port receives a most significant bit address signal, wherein if the memory array is defectless, the selection circuit outputs a selection signal to select the memory region to store data and makes the control unit control the address output port to output the most significant bit address signal to the address decoder circuit. If the memory array has the defect, the selection circuit outputs a selection signal to select the defectless memory region to store data and makes the control unit control the address output port to output the selection signal to the address decoder circuit.

Claims

1. A device for compensating a semiconductor memory defect, suitable for a semiconductor memory, said semiconductor memory including a control unit, an address decoder circuit, and a sensing circuit, said device comprising:

a memory array, comprising a memory region having a plurality of memory cells, said memory array being coupled to said address decoder circuit and said sensing circuit for storing data, wherein if said memory array has a defect, said memory array is divided into a plurality of sub-memory regions, one of said plurality of sub-memory regions is defectless, and wherein said memory array is replaced with said defectless sub-memory region for storing data;

a selection circuit, coupled to said control unit, said selection circuit selecting one of said memory region and said defectless sub-memory region to store data; and

a first input address buffer, coupled to said control unit and said address decoder circuit, said first input address buffer including an address input port and an address output port, said address input port receiving a most significant bit address signal;

wherein if said memory array is defectless, said selection circuit outputs a selection signal to select said memory region to store data and makes said control unit control said address output port to output said most significant bit address signal to said address decoder circuit;

if said memory array has said defect, said selection circuit outputs a selection signal to select said defectless memory region to store data and makes said control unit control said address output port to output said selection signal to said address decoder circuit.

2. The device of claim 1, further comprising a chip identification circuit coupled to said control unit, said chip identification circuit including an output terminal, a whole signal terminal, and a partial signal terminal, said chip identification circuit enabling one of said whole signal terminal and said partial signal terminal to output an identification signal at said output terminal to represent a memory size of said semiconductor memory.

3. The device of claim 1, further comprising a second input address buffer coupled to said address decoder circuit and said control unit, said second input address buffer including a plurality of address input ports and a plurality of address output ports, said plurality of address input ports receiving a plurality of address signals except said most significant bit address signal from said first input address buffer and sending said plurality of address signals to said address decoder circuit.

4. The device of claim 3, wherein said selection circuit includes:

an enable circuit, having an enable signal output terminal, wherein said enable circuit sends an enable signal via said control unit to said first input address buffer to determine said first input address buffer and outputs one of said most significant bit address signal and said selection signal;

a region selection circuit, coupled to said control unit, wherein when said memory region has said defect, said region selection circuit sending said selection signal via said control unit to said first input address buffer to select said defectless sub-memory region to store data; and

a NAND gate, having two input terminals and an output terminal, wherein one of said two input terminals of said NAND gate is coupled to said enable circuit to receive said enable signal, the other of said two input terminals of said NAND gate receives said control signal, and said output terminal of said NAND gate outputs a first buffer control signal to said first input address buffer via said control unit.

5. The device of claim 4, wherein said first input address buffer includes:

a NOR gate, having two input terminals and an output terminal, wherein one of said two input terminals of said NOR gate receives said first buffer control signal, the other of said two input terminals of said NOR gate receives said most significant bit address signal;

a first transmission gate module, having an input terminal and an output terminal, wherein said input terminal of said first transmission gate is coupled to said output terminal of said NOR gate, and said output terminal of said first transmission gate is coupled to said address decoder circuit;

a second transmission gate module, having an input terminal and an output terminal, wherein said input terminal of said second transmission gate receives said selection signal, said output terminal of said second transmission gate is connected to said output terminal of said first transmission gate module and coupled to said address decoder circuit; and

a first inverter, having an input terminal and an output terminal, wherein said input terminal of said first inverter receives said enable signal, said output terminal of said first inverter is coupled to said first transmission gate module and said second transmission gate module.

6. The device of claim 5, wherein said first transmission gate module includes:

a second inverter, having an input terminal and an output terminal, wherein said input terminal of said second inverter is coupled to said output terminal of said NOR gate; and

a first transmission gate, having an input terminal, an output terminal, an N-type MOS terminal and a P-type MOS terminal, wherein said input terminal of said first transmission gate is coupled to said output terminal of said second inverter, said N-type MOS terminal of said first transmission gate receives said enable signal, said P-type MOS terminal of said first transmission gate is coupled to said output terminal of said first inverter, said output of said first transmission gate is coupled to said address decoder circuit.

7. The device of claim 6, wherein said second transmission gate module includes:

a second transmission gate, having an input terminal, an output terminal, an N-type MOS terminal and a P-type MOS terminal, wherein said input terminal of said second transmission gate receives said selection signal, said P-type MOS terminal of said second transmission gate receives said enable signal, said N-type MOS terminal of said second transmission gate is coupled to said output terminal of said first inverter, said output terminal of said second transmission gate is connected to said output terminal of said first transmission gate and coupled to said address decoder circuit.

8. The device of claim 4, wherein said selection signal is an address-fixed address signal.

9. The device of claim 1, wherein the number of said sub-memory regions is a base 2 multiple exponential, said multiple is a positive integral.

10. A method for compensating a semiconductor memory defect, suitable for a semiconductor memory, said semiconductor memory including a memory region to store data for access and a plurality of address input ports for inputting an address signal, said address signal determining a location of said data in said memory region, said semiconductor memory including an identification code for representing a size of said semiconductor memory, said method comprising:

determining whether said memory region of said semiconductor memory has a defect;

wherein when said memory region of said semiconductor memory is found to be defective, said memory region is divided into a plurality of sub-memory regions, and wherein one of said plurality of sub-memory regions is defectless; and

replacing said memory region with said defectless sub-memory region to store said data.

11. The method of claim 10, wherein said step of replacing said memory region with said defectless sub-memory region to store said data includes:

disabling a most significant bit address of said plurality of address input ports; and

replacing said most significant bit address with a selection signal to select defectless sub-memory region.

12. The method of claim 11, wherein said step of replacing said memory region with said defectless sub-memory region to store said data further includes:

modifying said identification code of said semiconductor memory to represent a modified size of said semiconductor memory.