NON-VOLATILE MEMORIES, CARDS, AND SYSTEMS INCLUDING SHALLOW TRENCH ISOLATION STRUCTURES WITH BURIED BIT LINES
A non-volatile memory device can include a buried bit line in a substrate of a non-volatile memory device and a self-aligned shallow trench isolation region in the substrate that is self-aligned to the buried bit line.
This application is a Divisional of U.S. application Ser. No. 12/109,761, filed Apr. 25, 2008 in the United States Patent and Trademark Office, and claims priority from Korean Patent Application No. 10-2007-0041430, filed on Apr. 27, 2007, in the Korean Intellectual Property Office, the entire contents of all of which are hereby incorporated by reference.
FIELD OF THE INVENTIONThe present invention relates to the field of electronics, and more particularly, to methods of forming non-volatile memories and the devices so formed.
BACKGROUNDNon-volatile memory devices are widely used in various kinds of electronic products such as mobile telephones, etc. One type of non-volatile memory that has become popular is what is commonly referred to as NOR type flash memory. It is recognized that in conventional NOR flash memory, the metal contact employed in source/drain regions may use a significant area of the integrated circuit. Accordingly, one approach, sometimes referred to as buried bit line, has been used to avoid the formation of contacts in NOR type flash memory.
Non-volatile memories are also discussed in, for example, U.S. Patent Publication No. 2004/0169238 A1 to Lee et al., U.S. Patent Publication No. 2006/0180851 A1 to Lee et al., U.S. Pat. No. 5,526,307 to Yiu et al., U.S. Pat. No. 6,858,906 B2 to Lee et al, and U.S. Pat. No. 7,072,214 B2 to Jeong et al.
SUMMARYEmbodiments according to the invention can provide non-volatile memory devices, systems, and cards that include shallow trench isolation structures with buried bit lines. Pursuant to these embodiments, a non-volatile memory device can include a buried bit line in a substrate of a non-volatile memory device and a self-aligned shallow trench isolation region in the substrate that is self-aligned to the buried bit line.
In some embodiments according to the inventive concept, an electronic system can include a processor that is configured to coordinate operations of an electronic system and a volatile memory, that is electrically coupled to the processor, and that is configured to store and retrieve data responsive processor operations. A system interface, can be electrically coupled to the processor, and can be configured to provide communications between the processor and external systems and a non-volatile memory, can be electrically coupled to the processor, and can include at least one non-volatile memory device that includes a buried bit line in a substrate of a non-volatile memory device and a self-aligned shallow trench isolation region in the substrate that is self-aligned to the buried bit line.
In some embodiments according to the inventive concept, a memory card can include a non-volatile memory controller that is configured to coordinate operations of the memory card and a non-volatile memory, that can be electrically coupled to the non-volatile memory controller, and can include a non-volatile memory, which can include a buried bit line in a substrate of a non-volatile memory and a self-aligned shallow trench isolation region in the substrate that is self-aligned to the buried bit line.
The present invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown by way of example. The present invention may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Moreover, each embodiment described and illustrated herein includes its complementary conductivity type embodiment as well.
It will be understood that when an element is referred to as being “connected to,” “coupled to” or “responsive to” (and/or variants thereof) another element, it can be directly connected, coupled or responsive to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected to,” “directly coupled to” or “directly responsive to” (and/or variants thereof) another element, there are no intervening elements present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items and may be abbreviated as “/”.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” (and/or variants thereof), when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. In contrast, the term “consisting of” (and/or variants thereof) when used in this specification, specifies the stated number of features, integers, steps, operations, elements, and/or components, and precludes additional features, integers, steps, operations, elements, and/or components.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As described herein below in greater detail, shallow trench isolation structures can be formed self aligned to, for example, impurity regions that provide the buried bit line structures and NOR type flash memories. In particular, forming the shallow trench isolation structures so that they are self aligned to structures that provide the buried bit line of the non-volatile memory (i.e., the impurity regions) can help to substantially equalize ranks of the associated impurity regions (i.e., the lengths of the bit lines). For example, the formation of the self aligned shallow trench isolation structures can help to remove portions of the impurity regions which may have otherwise been formed misaligned by a conventional photolithographic process. As appreciated by the present inventors, using a photolithographic process to form the shallow trench isolation structures separate from the formation of the impurity regions to provide the buried bit lines can lead to misalignment errors thereby increasing the possibility of forming bit lines with different lengths within the same memory sector.
In further embodiments according to the invention, the impurity regions can be formed before the shallow trench isolation structures. In particular, the impurity regions may be formed in the substrate to provide immediately neighboring buried bit lines for the device. After the formation of the impurity region (i.e., the buried bit lines), a shallow trench isolation region can be formed in the substrate between the immediately neighboring buried bit lines. As appreciated by the present inventors, this approach can substantially equalize what may be otherwise different lengths of the immediately neighboring buried bit lines, which may be generated by conventional approaches. For example, as appreciated by the present inventors, if the shallow trench isolation structure is formed in the substrate using a standard photolithographic process (e.g., before the formation of the impurity regions), the subsequent formation of the impurity regions can be misaligned relative to the shallow trench isolation structures previously formed. Accordingly, this misalignment can lead to impurity regions (ultimately providing the buried bit lines) having different lengths.
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The layers described above are patterned to provide pluralities of openings 114 to define the lower pattern 110. Accordingly, the openings 114 expose respective portions of the substrate 100. Impurities are implanted into the exposed portions of the substrate 100 via the openings 114 to form impurity regions 120. It will be understood that the impurity regions 120 can provide buried bit lines for the NOR type flash memory in some embodiments according to the invention.
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As described herein, shallow trench isolation structures can be formed self aligned to, for example, impurity regions that provide the buried bit line structures and NOR type flash memories. In particular, forming the shallow trench isolation structures so that they are self aligned to structures that provide the buried bit line of the non-volatile memory (i.e., the impurity regions) can help to substantially equalize ranks of the associated impurity regions (i.e., the lengths of the bit lines). For example, the formation of the self aligned shallow trench isolation structures can help to remove portions of the impurity regions which may have otherwise been formed misaligned by a conventional photolithographic process. As appreciated by the present inventors, using a photolithographic process to form the shallow trench isolation structures separate from the formation of the impurity regions to provide the buried bit lines can lead to misalignment errors thereby increasing the possibility of forming bit lines with different lengths within the same memory sector.
In further embodiments according to the invention, the impurity regions can be formed before the shallow trench isolation structures. In particular, the impurity regions may be formed in the substrate to provide immediately neighboring buried bit lines for the device. After the formation of the impurity region (i.e., the buried bit lines), a shallow trench isolation region can be formed in the substrate between the immediately neighboring buried bit lines. As appreciated by the present inventors, this approach can substantially equalize what may be otherwise different lengths of the immediately neighboring buried bit lines, which may be generated by conventional approaches. For example, as appreciated by the present inventors, if the shallow trench isolation structure is formed in the substrate using a standard photolithographic process (e.g., before the formation of the impurity regions), the subsequent formation of the impurity regions can be misaligned relative to the shallow trench isolation structures previously formed. Accordingly, this misalignment can lead to impurity regions (ultimately providing the buried bit lines) having different lengths.
It will be apparent to those skilled in the art that various modifications and variations can be made in the invention. Thus, it is intended that the invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims
1. A non-volatile memory device comprising:
- a buried bit line in a substrate of a non-volatile memory device; and
- a self-aligned shallow trench isolation region in the substrate self-aligned to the buried bit line.
2. The non-volatile memory device according to claim 1 further comprising:
- a gate structure having the buried bit line self-aligned thereto, wherein the gate structure includes a protruding portion that extends into the substrate beyond a lower surface of the buried bit line.
3. An electronic system comprising:
- a processor configured to coordinate operations of an electronic system;
- a volatile memory, electrically coupled to the processor, configured to store and retrieve data responsive processor operations;
- a system interface, electrically coupled to the processor, configured to provide communications between the processor and external systems; and
- a non-volatile memory, electrically coupled to the processor, including at least one non-volatile memory device comprising: a buried bit line in a substrate of a non-volatile memory device; and a self-aligned shallow trench isolation region in the substrate self-aligned to the buried bit line.
4. The electronic system according to claim 3 further comprising:
- a gate structure having the buried bit line self-aligned thereto, wherein the gate structure includes a protruding portion that extends into the substrate beyond a lower surface of the buried bit line.
5. A memory card comprising:
- a non-volatile memory controller configured to coordinate operations of the memory card; and
- a non-volatile memory, electrically coupled to the non-volatile memory controller, including a non-volatile memory comprising: a buried bit line in a substrate of a non-volatile memory; and a self-aligned shallow trench isolation region in the substrate self-aligned to the buried bit line.
6. The memory card according to claim 5 further comprising:
- a gate structure having the buried bit line self-aligned thereto, wherein the gate structure includes a protruding portion that extends into the substrate beyond a lower surface of the buried bit line.
7. The memory card according to claim 6 wherein the gate structure comprises a U-shaped floating gate electrode.
Type: Application
Filed: Aug 22, 2011
Publication Date: Dec 8, 2011
Inventor: Wook Hyun KWON (Kyung-Ki Do)
Application Number: 13/214,571
International Classification: G06F 12/00 (20060101); H01L 29/788 (20060101); H01L 29/78 (20060101);