Line bending control for memory applications
A method for reducing bending of word lines in a memory cell includes a) providing a substrate including a plurality of word lines arranged adjacent to one another and above a plurality of transistors; b) depositing a layer of film on the plurality of word lines using a deposition process; c) after depositing the layer of film, measuring word line bending; d) comparing the word line bending to a predetermined range; e) based on the word line bending, adjusting at least one of nucleation delay and grain size of the deposition process; and f) repeating b) to e) one or more times using one or more substrates, respectively, until the word line bending is within the predetermined range.
1. A method for reducing bending of word lines in a memory cell, comprising:
a) providing a substrate including a plurality of word lines arranged adjacent to one another;
b) depositing a layer of film on the plurality of word lines using a deposition process;
c) after depositing the layer of film, measuring word line bending;
d) comparing the word line bending to a threshold tolerance range;
e) based on the word line bending, adjusting at least one of temperature and pressure of the deposition process; and
f) repeating b) to e) one or more times using one or more substrates, respectively, until the word line bending is within the threshold tolerance range.
2. The method of claim 1 , wherein the memory cell comprises a dynamic random access (DRAM) memory cell or a vertical NAND (VNAND) memory cell.
3. The method of claim 1 , wherein the temperature of the deposition process is adjusted in e).
4. The method of claim 1 , wherein the pressure of the deposition process is adjusted in e).
5. The method of claim 4 , wherein the temperature and the pressure of the deposition process are adjusted in e).
6. The method of claim 1 , wherein (e) includes decreasing the temperature of the deposition process if the word line bending is greater than the threshold tolerance range.
7. The method of claim 1 , wherein (e) includes increasing the temperature of the deposition process if the word line bending is less than the threshold tolerance range.
8. The method of claim 1 , wherein the layer of film is selected from a group consisting of molybdenum, tungsten, ruthenium and cobalt.
9. The method of claim 1 , further comprising arranging a liner layer between the plurality of word lines and the layer of film.
10. The method of claim 9 , wherein the liner layer includes titanium nitride.
11. The method of claim 1 , wherein (e) includes adjusting at least one of temperature and pressure of the deposition process to adjust nucleation delay of the deposition process.
12. The method of claim 11 , wherein the temperature of the deposition process is decreased in e) to increase the nucleation delay.
13. The method of claim 11 , wherein the pressure of the deposition process is decreased in e) to increase the nucleation delay.
14. The method of claim 11 , wherein the temperature and the pressure of the deposition process are decreased in e) to increase the nucleation delay.
15. The method of claim 1 , wherein (e) includes using an inhibitor species to adjust nucleation delay of the deposition process.
16. The method of claim 15 , wherein the inhibitor species is selected from a group consisting of molecular nitrogen and ammonia.
17. The method of claim 16 , wherein at least one of a concentration and an exposure time of the inhibitor species is increased in (e) to increase the nucleation delay.
18. The method of claim 1 , wherein (e) includes adjusting precursor chemistry or changing a mixture of precursors to adjust nucleation delay of the deposition process.
19. The method of claim 1 , wherein (e) includes adjusting at least one of temperature and pressure of the deposition process to control grain size of the deposition process.
20. The method of claim 1 , wherein (e) includes using impurities to control grain size of the deposition process.
21. The method of claim 1 , wherein (e) includes using insitu gases to control grain size of the deposition process and film roughness.