Method of decreasing fin bending

• US 9,552,978 B1
• Filed: 03/02/2016
• Issued: 01/24/2017
• Est. Priority Date: 03/02/2016
• Status: Active Grant

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Huang, Tong-Jyun, Feng, Li-Wei, Tsai, Shih-Hung, Jenq, Jyh-Shyang, Lin, Chien-Ting
• Primary Examiner(s): Maldonado, Julio J
• Assistant Examiner(s): Kolahdouzan, Hajar
• Application Number:
  US15/059,282
• Time in Patent Office: 328 Days
• Field of Search: 257/368, 438/427
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/0223 formation by oxidation, e.g. oxidation of the substrate
• 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02277 the reactions being activated by other means than plasma or thermal, e.g. photo-CVD
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/31056 the removal being a selective chemical etching step, e.g. selective dry etching through a mask
• CPC Class Codes: H01L 21/823431 with a particular manufacturing method of transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 21/823481 isolation region manufacturing related aspects, e.g. to avoid interaction of isolation region with adjacent structure
• CPC Class Codes: H01L 29/66795 with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/785 having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

A method of decreasing fin bending, includes providing a substrate including a plurality of fins, wherein a plurality of trenches are defined by the fins, the trenches include a first trench and a second trench, and the second trench is wider than the first trench. Later, a flowable chemical vapor deposition process is performed to form a silicon oxide layer covering the fins, filling up the first trench and partially filling in the second trench. After that, the silicon oxide layer is solidified by a UV curing process. Finally, after the UV curing process, the silicon oxide layer is densified by a steam anneal process.

Claims

1. A method of decreasing fin bending, comprising:

providing a substrate comprising a plurality of fins, wherein a plurality of trenches are defined by the fins, the trenches comprise a first trench and a second trench, and the second trench is wider than the first trench;

performing a flowable chemical vapor deposition process to form a silicon oxide layer covering the fins, filling up the first trench and partially filling in the second trench;

solidifying the silicon oxide layer by a UV curing process;

after the UV curing process, densifying the silicon oxide layer by a steam anneal process; and

after the steam anneal process, forming a high density plasma oxide layer covering the silicon oxide layer and filling in the second trench.

2. The method of decreasing fin bending of claim 1, further comprising:

performing a chemical mechanical polish process to remove part of the high density plasma oxide layer so as to align a top surface of the high density plasma oxide layer with a top surface of the silicon oxide layer.

3. The method of decreasing fin bending of claim 2, further comprising:

after the chemical mechanical polish process, performing an etching back process to etch the silicon oxide layer and the high density plasma oxide layer to make the top surface of the silicon oxide layer lower than an uppermost surface of each of the fins.

4. The method of decreasing fin bending of claim 3, wherein there is not any anneal process performed between the etching back process and the chemical mechanical polish process.

5. The method of decreasing fin bending of claim 1, wherein a shrinking force is formed within the silicon oxide layer in the first trench by performing the UV curing process on the silicon oxide layer, and the shrinking force points away from the second trench.

6. The method of decreasing fin bending of claim 1, wherein an expanding force is formed within the silicon oxide layer in the first trench by performing the steam anneal process on the silicon oxide layer, and the expanding force points toward the second trench.

7. The method of decreasing fin bending of claim 1, wherein the steam anneal process comprises oxidizing the silicon oxide layer in hydrogen/oxygen ambient.