Offset-printing method for three-dimensional printed memory with multiple bits-per-cell
The present invention discloses an offset-printing method for a three-dimensional printed memory with multiple bits-per-cell. The mask-patterns for different bits-in-a-cell are merged onto a multi-region data-mask. At different printing steps, a wafer is offset by different values with respect to the data-mask. Accordingly, data-patterns from a same data-mask are printed into different bits-in-a-cell.
1. An offset-printing method for a three-dimensional printed memory with multiple bits-per-cell, comprising the steps of:
1) forming a substrate circuit on a semiconductor wafer, wherein said wafer comprises at least two adjacent dice including a first die and a second die;
2) a first printing step for transferring a first mask pattern of a data-mask to a first data-coding layer, wherein an origin of said data-mask is initially aligned to an origin of said first die at said first printing step;
3) a second printing step for transferring a second mask pattern of said data-mask to a second data-coding layer above said first data-coding layer, wherein said origin of said data-mask is initially aligned to an origin of said second die at said second printing step;
wherein said first and second mask patterns are located on a same data-mask; said first and second data-coding layers are formed in a same memory level.
2. The method according to claim 1 , wherein said data-mask comprises at least first and second mask-regions whose mask patterns are transferred to said first and second data-coding layers.
3. The method according to claim 2 , wherein the mask pattern of said first mask-region is transferred to said first data-coding layer in said first die at said first printing step.
4. The method according to claim 2 , wherein the mask pattern of said second mask-region is transferred to said first data-coding layer in said second die at said first printing step.
5. The method according to claim 2 , wherein the mask pattern of said first mask-region is transferred to said second data-coding layer in said second die at said second printing step.
6. The method according to claim 2 , wherein the mask pattern of said second mask-region is transferred to said second data-coding layer in said first die at said second printing step.
7. The method according to claim 2 , wherein said first data-coding layer of said first die stores a first data-array.
8. The method according to claim 2 , wherein said second data-coding layer of said first die stores a second data-array.
9. The method according to claim 2 , wherein said first data-coding layer of said second die stores a second data-array.
10. The method according to claim 2 , wherein said second data-coding layer of said second die stores a first data-array.
11. The method according to claim 1 , wherein a displacement between said first and second dice is smaller than a stepping distance of said first printing step.
12. The method according to claim 11 , wherein said stepping distance of said first printing step is at least twice said displacement between said first and second dice.
13. The method according to claim 1 , wherein a displacement between said first and second dice is smaller than a stepping distance of said second printing step.
14. The method according to claim 13 , wherein a stepping distance of said second printing step is at least twice said displacement between said first and second dice.
15. The method according to claim 1 , wherein a total number of data-masks is fewer than a total number of data-coding layers.
16. The method according to claim 15 , wherein said total number of data-masks is one.
17. The method according to claim 1 , wherein said first printing step is photo-lithography.
18. The method according to claim 1 , wherein said second printing step is photo-lithography.
19. The method according to claim 1 , wherein said first printing step is imprint-lithography.
20. The method according to claim 1 , wherein said second printing step is imprint-lithography.