Nonvolatile semiconductor memory device

• US 9,236,127 B2
• Filed: 10/01/2014
• Issued: 01/12/2016
• Est. Priority Date: 10/11/2013
• Status: Active Grant

• Current Assignee: Mosaid Technologies Incorporated (MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management))
• Original Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Inventors: Rhie, Hyoung Seub
• Primary Examiner(s): BERNSTEIN, ALLISON
• Application Number:
  US14/503,709
• Publication Number:
  US 20150103600A1
• Time in Patent Office: 468 Days
• US Class Current: 1/1
• CPC Class Codes: G11C 16/0466 comprising cells with charge storage in an insulating layer, e.g. metal-nitride-oxide-silicon [MNOS], silicon-oxide-nitride-oxide-silicon [SONOS] G11C16/0483, G11C16/0491 take precedence
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: H01L 29/66833 with a charge trapping gate insulator, e.g. MNOS transistors
• CPC Class Codes: H10B 43/20 characterised by three-dimensional arrangements, e.g. with cells on different height levels

Abstract

A non-volatile memory device, including: a substrate; a plurality of string stacks disposed over the substrate, each string stack including a long axis and a short axis in a plane parallel to the substrate, the long axis extending along a y-direction and the short axis extending along an x-direction, each string stack including a plurality of strings being stacked in a direction vertical to the substrate and having a first end and a second end at different locations in the y-direction, the plurality of string stacks including a first and a second set of string stacks, at least some of the string stacks of the first set of string stacks being offset along the x-direction from at least some of the string stacks of the second set of string stacks.

Claims

1. A non-volatile memory device, comprising:

a substrate;

a plurality of string stacks disposed over the substrate,

each string stack comprising a long axis and a short axis in a plane parallel to the substrate, the long axis extending along a y-direction and the short axis extending along an x-direction,

each string stack comprising a plurality of strings being stacked in a direction vertical to the substrate and having a first end and a second end at different locations in the y-direction,

the plurality of string stacks comprising a first and a second set of string stacks,

the first set of string stacks comprising at least two string stacks located at the same location in the y-direction and at different locations in the x-direction forming a repetitive pattern with a pitch A,

the second set of string stacks being adjacent to the first set of string stacks and comprising at least two string stacks located at the same location in the y-direction and at different locations in the x-direction forming a repetitive pattern with a pitch A,

the first set of string stacks and the second set of string stacks being at different locations in the y-direction,

at least some of the string stacks of the first set of string stacks being offset along the x-direction from at least some of the string stacks of the second set of string stacks by a distance B, the distance B being different from an integer multiple of the pitch A.

2. The non-volatile memory device of claim 1, wherein the non-volatile memory device is a NAND Flash device.

3. The nonvolatile memory device of claim 1, comprising:

a plurality of pads disposed over the substrate,

each pad having at least a first and a second sidewall,

each of the first sidewalls facing a same direction relative to other first sidewalls,

the first sidewalls facing directions opposite the second sidewalls, and,

the first and second sidewalls facing directions parallel to the y-direction.

4. The non-volatile memory device of claim 3, wherein:

the pads are bit line pads, each bit line pad being electrically connected to a bit line.

5. The non-volatile memory device of claim 3, wherein:

the pads are source line pads.

6. The non-volatile memory device of claim 3, wherein:

the plurality of pads comprises at least a first and a second stack of pads,

each stack of pads comprising a plurality of pads being stacked in a direction vertical to the substrate.

7. The non-volatile memory device of claim 6, wherein:

the first set of string stacks is connected to the first stack of pads,

the second set of string stacks is connected to the second stack of pads,

each string stack of the first set of string stacks being oriented in the same y-direction.

8. The non-volatile memory device of claim 7, wherein:

each of the first sidewalls of the first stack of pads is disposed to face a space between at least two string stacks of the second set of string stacks.

9. The non-volatile memory device of claim 6, wherein:

the first set of string stacks is connected to the first stack of pads,

the second set of string stacks is connected to the first stack of pads,

the string stacks of the first and the second set of string stacks are oriented in opposite directions to form an alternating even-odd orientation.

10. The non-volatile memory device of claim 9, wherein:

each of the first sidewalls of the first stack of pads is disposed to face a space between at least two string stacks of the second set of string stacks.

11. The non-volatile memory device of claim 1, wherein:

the distance B is substantially half of the pitch A.

12. The non-volatile memory device of claim 3, wherein:

portions of the plurality of pads are fabricated using a tilted ion beam bombardment.