Chemical vapor deposition of high conductivity, adherent thin films of ruthenium
View Patent ↗A multi-step method for depositing ruthenium thin films having high conductivity and superior adherence to the substrate is described. The method includes the deposition of a ruthenium nucleation layer followed by the deposition of a highly conductive ruthenium upper layer. Both layers are deposited using chemical vapor deposition (CVD) employing low deposition rates.
1. A method of forming a ruthenium-containing film on a substrate, said method comprising a pulsed deposition process including (i) vapor deposition of ruthenium on said substrate from a ruthenium precursor vapor, (ii) deoxygenating the ruthenium deposited on said substrate under process conditions that are more reducing than those of said vapor deposition of ruthenium, and (iii) repeating said vapor deposition (i) and deoxygenating (ii) in continuously repeated alternating sequence until a predetermined thickness of said ruthenium-containing film has been achieved, wherein said film has a resistivity of less than about 30 μΩ-cm.
2. The method of claim 1 , wherein temporal length of deposition in each succeeding repetition of said vapor deposition is substantially equal, and said temporal length of deposition in each succeeding repetition of said vapor deposition is less than temporal length of deposition in a first occurrence of said vapor deposition.
3. The method of claim 2 , wherein said first occurrence and each said succeeding repetition of said vapor deposition, are each conducted at surface reaction rate-limited deposition conditions.
4. The method of claim 1 , wherein said more reducing process conditions include at least one of lower pressure, lower oxygen content, higher temperature and higher reducing agent content.
5. The method of claim 1 , wherein said predetermined thickness is greater than 40 Å.
6. The method of claim 1 , wherein said predetermined thickness is less than 120 Å.
7. The method of claim 1 , wherein said predetermined thickness is less than 100 Å.
8. The method of claim 1 , wherein said predetermined thickness is less than 80 Å.
9. The method of claim 1 , wherein said predetermined thickness is less than 65 Å.
10. The method of claim 1 , wherein said predetermined thickness is less than 60 Å.
11. The method of claim 1 , wherein said pulsed deposition process includes a constant temperature.
12. The method of claim 1 , wherein said pulsed deposition process includes a constant temperature of 280° C.
13. The method of claim 1 , wherein said pulsed deposition process includes a constant temperature of 300° C.
14. The method of claim 1 , wherein said more reducing process conditions include pressure of 9 Torr.
15. The method of claim 1 , wherein said more reducing process conditions include H 2 content of 4%.