Mixed Three-Dimensional Memory

Abstract

The present invention discloses a mixed three-dimensional memory (3D-M.sub.x). Both data and codes are stored in a same 3D-M.sub.x die. Data, which require a lower cost per bit and can tolerate slow access, are stored in large memory arrays, whereas codes, which require fast access and can tolerate a higher cost per bit, are stored in small memory arrays.

Claims

1. A mixed three-dimensional memory (3D-M.sub.x), comprising: a first memory block for storing data, said first memory block comprising a plurality of vertically stacked memory levels including a first topmost memory level, said first topmost memory level comprising only a first memory array; a second memory block for storing codes, said second memory block comprising another plurality of vertically stacked memory levels including a second topmost level, said second topmost memory level comprising only a second memory array; wherein said second memory block is located side-by-side from said first memory block, said first memory array is larger than said second memory array.

2. The memory according to claim 1, wherein said memory is a three-dimensional random-access memory (3D-RAM).

3. The memory according to claim 1, wherein said memory is a three-dimensional read-only memory (3D-ROM).

4. The memory according to claim 3, wherein said 3D-ROM is a three-dimensional mask-programmed read-only memory (3D-MPROM).

5. The memory according to claim 3, wherein said 3D-ROM is a three-dimensional electrically-programmable read-only memory (3D-EPROM).

6. The memory according to claim 5, wherein said 3D-ROM is a three-dimensional one-time-programmable read-only memory (3D-OTP).

7. The memory according to claim 5, wherein said 3D-ROM is a three-dimensional multiple-time-programmable read-only memory (3D-mTP).

8. The memory according to claim 1, wherein said data are digital books, digital maps, digital music, digital movies, and/or digital videos.

9. The memory according to claim 1, wherein said codes are operating system, software, and/or digital games.

10. A mixed three-dimensional memory (3D-M.sub.x) comprising a 3D-M block, said 3D-M block further comprising a plurality of vertically stacked memory levels including a topmost memory level and at least an intermediate memory level, wherein: said topmost memory level comprises only a first memory array; said intermediate memory level comprises at least second and third memory arrays, wherein said second and third memory arrays do not share any address-select line; wherein said first memory array fully covers both said second and third memory arrays.

11. The memory according to claim 10, wherein said memory is a three-dimensional random-access memory (3D-RAM).

12. The memory according to claim 10, wherein said memory is a three-dimensional read-only memory (3D-ROM).

13. The memory according to claim 12, wherein said 3D-ROM is a three-dimensional mask-programmed read-only memory (3D-MPROM).

14. The memory according to claim 12, wherein said 3D-ROM is a three-dimensional electrically-programmable read-only memory (3D-EPROM).

15. The memory according to claim 14, wherein said 3D-ROM is a three-dimensional one-time-programmable read-only memory (3D-OTP).

16. The memory according to claim 14, wherein said 3D-ROM is a three-dimensional multiple-time-programmable read-only memory (3D-mTP).

17. The memory according to claim 10, wherein said first memory array stores data.

18. The memory according to claim 17, wherein said data are digital books, digital maps, digital music, digital movies, and/or digital videos.

19. The memory according to claim 10, wherein said second and third memory arrays store codes.

20. The memory according to claim 19, wherein said codes are operating system, software, and/or digital games.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1A is a cross-sectional view of a prior-art three-dimensional memory (3D-M); FIG. 1B is a die diagram of the prior-art 3D-M;

[0018] FIG. 2 illustrates the relationship between the array efficiency, the memory speed and the array size;

[0019] FIG. 3 is a die diagram of a preferred 3D-M.sub.x with mixed memory blocks;

[0020] FIG. 4 is a cross-sectional view of a preferred 3D-M.sub.x with mixed memory arrays.

[0021] It should be noted that all the drawings are schematic and not drawn to scale. Relative dimensions and proportions of parts of the device structures in the figures have been shown exaggerated or reduced in size for the sake of clarity and convenience in the drawings. The same reference symbols are generally used to refer to corresponding or similar features in the different embodiments. Although the examples shown in these figures are 3D-MPROM, this concept can be readily extended to other types of 3D-M.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Those of ordinary skills in the art will realize that the following description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons from an examination of the within disclosure.

[0023] Referring now to FIG. 2, the relationships between the array efficiency, the memory speed and the array size are disclosed. When the memory arrays are small, because the peripheral circuit of each memory array has a fixed size, the array efficiency degrades. As the memory arrays become larger, the array efficiency improves. However, as the parasitic capacitance and resistance increase, the access speed suffers.

[0024] In order to store both data and codes in a same 3D-M die while meeting their respective requirements on cost and speed, a mixed 3D-M (3D-M.sub.x) is disclosed. It comprises memory arrays (or, memory blocks) of different sizes. Data (e.g. digital books, digital maps, digital music, digital movies, and/or digital videos), which require a lower cost per bit and can tolerate slow access, are stored in large memory arrays (or, memory blocks), whereas codes (e.g. operating systems, software, and/or digital games), which require fast access and can tolerate a higher cost per bit, are stored in small memory arrays (or, memory blocks). The 3D-M.sub.x die could comprise mixed memory blocks or mixed memory arrays. In the mixed memory blocks (FIG. 3), the memory blocks with different sizes are formed side-by-side. In the mixed memory arrays (FIG. 4), a plurality of small side-by-side memory arrays are formed underneath a single large memory array.

[0025] Referring now to FIG. 3, a preferred 3D-M.sub.x with mixed memory blocks is shown. The 3D-M.sub.x die 2000 comprises a plurality of memory blocks 1a, 1b, 1ac-1dd. The memory blocks 1a, 1b contain larger memory arrays than those in memory blocks 1ac-1dd. As such, the memory blocks 1a, 1b can be used to store data, e.g. digital books, digital maps, digital music, digital movies, and/or digital videos, whereas the memory blocks 1ac-1dd can be used to store codes, e.g. operating systems, software, and/or digital games.

[0026] Referring now to FIG. 4, a preferred 3D-M.sub.x with mixed memory arrays is shown. This preferred 3D-M.sub.x comprises two memory levels 10, 20 with the memory level 20 stacked above the memory level 10. The memory level 20 is the topmost memory level and comprises a single memory array 200A, while the memory level 10 is an intermediate memory level and comprises two side-by-side memory arrays 100A, 100A′. Apparently, the memory array 200A in the memory level 20 is much larger than the memory arrays 100A, 100A′ in the memory level 10. The memory array 200A can be used to store data, e.g. digital books, digital maps, digital music, digital movies, and/or digital videos, whereas the memory arrays 100A, 100A′ can be used to store codes, e.g. operating systems, software, and/or digital games.

[0027] While illustrative embodiments have been shown and described, it would be apparent to those skilled in the art that many more modifications than that have been mentioned above are possible without departing from the inventive concepts set forth therein. For example, the mixed 3D-M disclosed in the present invention could be 3D-RAM or 3D-ROM. It could be either mask-programmed, or electrically-programmable. It could be further one-time-programmable, or multiple-time-programmable. The invention, therefore, is not to be limited except in the spirit of the appended claims