Methods for producing 3D semiconductor memory device and structure utilizing alignment marks
A method for producing a 3D memory device, the method including: providing a first level including a first single crystal layer; forming first alignment marks and control circuits in and on the first level, where the control circuits include first single crystal transistors, where the control circuits include at least two metal layers; forming at least one second level disposed on top of the first level; performing a first etch step within the second level; forming at least one third level disposed on top of the at least one second level; performing a second etch step within the third level; and performing additional processing steps to form a plurality of first memory cells within the second level and a plurality of second memory cells within the third level, where the first memory cells include second transistors, and where the second memory cells include third transistors.
1. A method for producing a 3D memory device, the method comprising:
providing a first level comprising a first single crystal layer;
forming first alignment marks and control circuits in and on said first level,
wherein said control circuits comprise first single crystal transistors, and
wherein said control circuits comprise at least two interconnection metal layers;
forming at least one second level disposed on top of said control circuits;
performing a first etch step comprising a first etching of first holes within said second level;
forming at least one third level disposed on top of said at least one second level;
performing a second etch step comprising a second etching of second holes within said third level; and
performing additional processing steps to form a plurality of first memory cells within said second level and a plurality of second memory cells within said third level,
wherein said forming at least one second level comprises forming lithography holes atop of said first alignment marks to enable performing lithography steps aligned to said first alignment marks,
wherein said first etch step comprises performing at least one of said lithography steps aligned to said first alignment marks,
wherein said second etch step comprises performing at least one of said lithography steps aligned to said first alignment marks,
wherein said first memory cells comprise second transistors, and
wherein said second memory cells comprise third transistors.
2. The method according to claim 1 ,
wherein said control circuits comprise control of said first memory cells and of said second memory cells, and
wherein said first memory cells are positioned at least partially atop of said control circuits.
3. The method according to claim 1 ,
wherein said first memory cells and said second memory cells are a NAND nonvolatile type memory.
4. The method according to claim 1 ,
wherein said second level comprises at least two overlying layers each comprising different materials, and
wherein said different materials each comprise a differing etch rate and are selectively etchable with respect to each other.
5. The method according to claim 1 ,
wherein at least one of said second transistors has a channel, a source, and a drain, and
wherein said channel, said source, and said drain comprise a same doping type.
6. The method according to claim 1 ,
wherein said first etch step comprises use of one or more Reactive Ion Etching (RIE) processes.
7. The method according to claim 1 ,
wherein said etching second holes comprises performing a lithography step so that said second holes are aligned to said first holes.
8. A method for producing a 3D memory device, the method comprising:
providing a first level comprising a first single crystal layer;
forming first alignment marks and control circuits in and on said first level,
wherein said control circuits comprise first single crystal transistors,
wherein said control circuits comprise at least two metal layers;
forming at least one second level disposed on top of said control circuits;
performing a first etch step within said second level;
forming at least one third level disposed on top of said at least one second level;
performing a second etch step within said third level; and
performing additional processing steps to form a plurality of first memory cells within said second level and a plurality of second memory cells within said third level,
wherein said first etch step comprises performing a lithography step aligned to said first alignment marks,
wherein said first memory cells comprise second transistors, and
wherein said second memory cells comprise third transistors.
9. The method according to claim 8 ,
wherein said control circuits comprise control of said first memory cells and of said second memory cells, and
wherein said first memory cells are at least partially atop of said control circuits.
10. The method according to claim 8 ,
wherein said first memory cells and said second memory cells are a NAND nonvolatile type memory.
11. The method according to claim 8 ,
wherein said second level comprises at least two overlying layers each comprising different materials, and
wherein said different materials each comprise a differing etch rate and are selectively etchable with respect to each other.
12. The method according to claim 8 ,
wherein said forming at least one second level comprises forming lithography holes directly atop of said first alignment marks to enable performing lithography steps aligned to said first alignment marks.
13. The method according to claim 8 ,
wherein at least one of said second transistors has a channel, a source, and a drain, and
wherein said channel, said source, and said drain comprise a same doping type.
14. The method according to claim 8 ,
wherein said first etch step comprises etching first holes using of one or more Reactive Ion Etching (RIE) processes.
15. A method for producing a 3D memory device, the method comprising:
providing a first level comprising a first single crystal layer;
forming first alignment marks and control circuits in and on said first level,
wherein said control circuits comprise first single crystal transistors,
wherein said control circuits comprise at least two metal layers;
forming at least one second level disposed on top of said first level;
performing a first etch step within said second level;
forming at least one third level disposed on top of said at least one second level;
performing a second etch step within said third level; and
performing additional processing steps to form a plurality of first memory cells within said second level and a plurality of second memory cells within said third level,
wherein said first memory cells comprise second transistors, and
wherein said second memory cells comprise third transistors.
16. The method according to claim 15 ,
wherein said control circuits comprise control of said first memory cells and of said second memory cells, and
wherein said first memory cells are at least partially atop of said control circuits.
17. The method according to claim 15 ,
wherein said first memory cells and said second memory cells are a NAND nonvolatile type memory.
18. The method according to claim 15 ,
wherein said second level comprises at least two overlying layers each comprising different materials, and
wherein said different materials each comprise a differing etch rate and are selectively etchable with respect to each other.
19. The method according to claim 15 ,
wherein said first etch step comprises etching first holes and performing a lithography step aligned to said first alignment marks.
20. The method according to claim 15 ,
wherein said forming at least one second level comprises forming lithography holes directly atop of said first alignment marks to enable performing lithography steps aligned to said first alignment marks.