Reduced pattern loading using silicon oxide multi-layers

• US 8,716,154 B2
• Filed: 10/03/2011
• Issued: 05/06/2014
• Est. Priority Date: 03/04/2011
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Bhatia, Sidharth, Gee, Paul Edward, Venkataraman, Shankar
• Primary Examiner(s): ARORA, AJAY
• Application Number:
  US13/251,621
• Publication Number:
  US 20120225565A1
• Time in Patent Office: 946 Days
• Field of Search: 438/790
• US Class Current: 438/790
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence

Abstract

Aspects of the disclosure pertain to methods of depositing conformal silicon oxide multi-layers on patterned substrates. The conformal silicon oxide multi-layers are each formed by depositing multiple sub-layers. Sub-layers are deposited by flowing BIS(DIETHYLAMINO)SILANE (BDEAS) and an oxygen-containing precursor into a processing chamber such that a relatively uniform dielectric growth rate is achieved across the patterned substrate surface. A plasma treatment may follow formation of sub-layers to further improve conformality and to decrease the wet etch rate of the conformal silicon oxide multi-layer film. The deposition of conformal silicon oxide multi-layers grown according to embodiments have a reduced dependence on pattern density while still being suitable for non-sacrificial applications.

Claims

1. A method for forming a conformal silicon oxide multi-layer on a patterned substrate in a substrate processing region of a processing chamber, wherein the patterned substrate has a densely patterned region and a sparsely patterned region, the method comprising sequential steps of:

performing a first cycle of chemical vapor deposition comprising the operations;

flowing BDEAS into the substrate processing region,

flowing a first oxygen-containing precursor into the substrate processing region, wherein the operations of flowing the BDEAS and flowing the first oxygen-containing precursor are concurrent, and

forming a first conformal silicon oxide sub-layer of the conformal silicon oxide multi-layer on the patterned substrate from the BDEAS and the first oxygen-containing precursor by chemical vapor deposition;

removing unreacted and partially-reacted precursors from the substrate processing region; and

performing a second cycle of chemical vapor deposition comprising the operations;

flowing BDEAS into the substrate processing region,

flowing a second oxygen-containing precursor into the substrate processing region, and

forming a second conformal silicon oxide sub-layer of the conformal silicon oxide multi-layer on the patterned substrate from the BDEAS and the second oxygen-containing precursor by chemical vapor deposition,

wherein a thickness of the first conformal silicon oxide sub-layer is about 100 Å

or less.

2. The method of claim 1 wherein flowing the first and second oxygen-containing precursors into the substrate processing region comprises flowing molecular oxygen into the substrate processing region.

3. The method of claim 2 wherein the first and second oxygen-containing precursors consists essentially of molecular oxygen (O₂).

4. The method of claim 2 wherein the first and second oxygen-containing precursors contains essentially no ozone (O₃).

5. The method of claim 1 wherein flowing the first and second oxygen-containing precursors comprise flowing molecular oxygen and ozone into the substrate processing region.

6. The method of claim 5 wherein a flow rate of the ozone is less than about 300 sccm.

7. The method of claim 1 wherein a first thickness of the conformal silicon oxide multi-layer in the densely patterned region is within 10% of a second thickness in the sparsely patterned region.

8. The method of claim 7 wherein the first and second thicknesses are measured on a substantially-vertical surface of the patterned substrate, wherein the substantially-vertical surface is substantially perpendicular to the patterned substrate.

9. The method of claim 7 wherein the two thicknesses of the conformal silicon oxide multi-layer in the densely and sparsely patterned regions are measured on a substantially-horizontal surface of the patterned substrate.

10. The method of claim 1 wherein a first thickness of the conformal silicon oxide multi-layer in the densely patterned region is within 3% of a second thickness in the sparsely patterned region.

11. The method of claim 1 wherein the operation of flowing BDEAS comprises flowing BDEAS at a rate greater than or about 100 mg/min.

12. The method of claim 1 further comprising treating the first conformal silicon oxide sub-layer with a plasma after performing the first cycle and before performing the second cycle of chemical vapor deposition.

13. The method of claim 12 wherein the plasma is formed from at least one of argon, helium, ozone or nitrogen (N₂).

14. The method of claim 12 wherein the plasma is formed using a frequency greater than or about 5 MHz and a power greater than or about 300 Watts.

15. The method of claim 1 wherein a pressure in the substrate processing region during formation of the first conformal silicon oxide sub-layer is below or about 350 Torr.

16. The method of claim 1 wherein a temperature of the patterned substrate during formation of the first conformal silicon oxide sub-layer is below or about 400°

C.

17. The method of claim 1 wherein the thickness of the first conformal silicon oxide sub-layer is about 50 Å

or less.

18. The method of claim 1 wherein an average exposed substantially-vertical area prior to deposition in the densely patterned region exceeds that of the sparsely patterned region by a multiplicative factor of about 2.

19. The method of claim 1 further comprising an operation of flowing a carrier gas which carries the BDEAS into the substrate processing region during the first cycle of chemical vapor deposition.