Semiconductor device, fabricating method thereof, and fabricating method of memory

• US 9,899,396 B1
• Filed: 12/01/2016
• Issued: 02/20/2018
• Est. Priority Date: 12/01/2016
• Status: Active Grant

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: Lee, Chih-Hsiung, Lee, Chien-Ying, Han, Tzung-Ting
• Primary Examiner(s): Oh, Jaehwan
• Application Number:
  US15/366,682
• Time in Patent Office: 446 Days
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/76229 Concurrent filling of a plurality of trenches having a different trench shape or dimension, e.g. rectangular and V-shaped trenches, wide and narrow trenches, shallow and deep trenches
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H10B 41/42 Simultaneous manufacture of periphery and memory cells
• CPC Class Codes: H10B 41/50 characterised by the boundary region between the core region and the peripheral circuit region

Abstract

A method for fabricating a semiconductor device includes: forming a first trench and a wider second trench in a substrate and a material layer formed thereon, forming a flowable isolation material covering the material layer and filling in the first and second trenches, removing a portion of the flowable isolation material in the second trench so that the thickness of the remaining flowable isolation material on the sidewall of the second trench is 200 Å to 1000 Å, and forming a non-flowable isolation material on the flowable isolation material.

Claims

1. A method for fabricating a semiconductor device, comprising:

forming a material layer on a substrate;

forming a first trench and a second trench in the substrate and the material layer, wherein a width of the first trench is smaller than a width of the second trench;

forming a flowable isolation material covering the material layer and filling in the first trench and the second trench;

removing a portion of the flowable isolation material in the second trench, so that a thickness of the remaining flowable isolation material on a sidewall of the second trench is in a range of 200 Å

to 1000 Å

; and

forming a non-flowable isolation material on the flowable isolation material.

2. The method of claim 1, wherein after removing the portion of the flowable isolation material in the second trench, a distance between a top surface of the remaining flowable isolation material on a bottom of the second trench and a top surface of the substrate is larger than ⅓

of a distance between the top surface of the substrate and the bottom of the second trench.

3. The method of claim 1, wherein the thickness of the remaining flowable isolation material on a bottom of the second trench is larger than 200 Å

.

4. The method of claim 1, further comprising:

after the first and second trenches are formed but before the flowable isolation material is formed, forming a buffer layer on the substrate and the material layer.

5. The method of claim 1, further comprising:

after the flowable isolation material is formed but before the portion of the flowable isolation material in the second trench is removed, performing a semi-curing treatment to the flowable isolation material.

6. The method of claim 1, wherein removing the portion of the flowable isolation material in the second trench comprises:

forming, on the flowable isolation material, a patterned mask layer that exposes a portion of the flowable isolation material above the second trench; and

performing anisotropic etching with the patterned mask layer as an etching mask.

7. The method of claim 1, wherein the thickness of the remaining flowable isolation material on the sidewall of the second trench is uniform.

8. A method for fabricating a memory, comprising:

forming a gate dielectric material layer and a gate material layer in sequence on a substrate;

forming a plurality of first trenches and a plurality of second trenches in the gate material layer, the gate dielectric material layer and the substrate, wherein a plurality of floating gates and a gate dielectric layer are defined, and a width of the first trenches is smaller than a width of the second trenches;

filling a flowable isolation material in the first trenches and the second trenches;

removing a portion of the flowable isolation material in each second trench, so that a thickness of the remaining flowable isolation material on a sidewall of the second trench is in a range of 200 Å

to 1000 Å

;

forming a non-flowable isolation material in a remaining portion of the flowable isolation material in each second trench;

removing a portion of the flowable isolation material in each first trench;

forming an inter-gate dielectric layer on each floating gate; and

forming a plurality of control gates on the inter-gate dielectric layer.

9. The method of claim 8, wherein after removing the portion of the flowable isolation material in each second trench, a distance between a top surface of the remaining flowable isolation material on a bottom of the second trench and a top surface of the substrate is larger than ⅓

of a distance between the top surface of the substrate and the bottom of the second trench.

10. The method of claim 8, wherein the thickness of the remaining flowable isolation material on a bottom of each second trench is larger than 200 Å

.

11. The method of claim 8, further comprising:

after the first trenches and the second trenches are formed but before the flowable isolation material is filled in the first trenches and the second trenches, forming a buffer layer on the substrate, the floating gates and the gate dielectric layer.

12. The method of claim 8, further comprising:

after the flowable isolation material is filled in the first trenches and the second trenches but before the portion of the flowable isolation material in each second trench is removed, performing a semi-curing treatment to the flowable isolation material.

13. The method of claim 8, wherein removing the portion of the flowable isolation material in each second trench comprises:

forming, on the flowable isolation material, a patterned mask layer that exposes a portion of the flowable isolation material above the second trench; and

performing anisotropic etching with the patterned mask layer as an etching mask.

14. The method of claim 8, wherein the thickness of the remaining flowable isolation material on the sidewall of each second trench is uniform.