Semiconductor device and manufacturing method therefor

• US 10,644,017 B2
• Filed: 07/16/2018
• Issued: 05/05/2020
• Est. Priority Date: 09/08/2017
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Yamashita, Tomohiro
• Primary Examiner(s): Diaz, Jose R
• Application Number:
  US16/036,324
• Publication Number:
  US 20190081057A1
• Time in Patent Office: 659 Days
• CPC Class Codes: H01L 29/40117 the electrodes comprising a charge-trapping insulator
• CPC Class Codes: H01L 29/42344 with at least one additional gate, e.g. program gate, erase gate or select gate
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/66545 using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
• 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 29/66833 with a charge trapping gate insulator, e.g. MNOS transistors
• CPC Class Codes: H01L 29/7851 with the body tied to the substrate
• CPC Class Codes: H01L 29/792 with charge trapping gate insulator, e.g. MNOS-memory transistors
• CPC Class Codes: H10B 43/30 characterised by the memory core region
• CPC Class Codes: H10B 43/40 characterised by the peripheral circuit region

Abstract

On the upper surface of a fin projecting from the upper surface of a semiconductor substrate, there are formed a control gate electrode through a gate insulating film and a memory gate electrode through a gate insulating film. A semiconductor region is formed in the fin beside the control gate electrode. On the semiconductor region, an insulating film, a first interlayer insulating film, and a second interlayer insulating film are formed. A plug reaching the semiconductor region is formed in the second interlayer insulating film, the first interlayer insulating film, and the insulating film. A cap film is formed between the control gate electrode and the interlayer insulating film, and the plug is positioned also right above the cap film.

Claims

1. A semiconductor device comprising:

a first projecting unit which is a part of a semiconductor substrate, projects from an upper surface of the semiconductor substrate, and extends in a first direction along a main surface of the semiconductor substrate;

a first gate electrode which is formed over an upper surface and a side surface of the first projecting unit through a first gate insulating film, and extends in a second direction orthogonal to the first direction;

a second gate electrode which is formed over the upper surface and the side surface of the first projecting unit through a second gate insulating film, is adjacent to a first side surface of the first gate electrode through the second gate insulating film, and extends in the second direction;

a sidewall spacer which is formed beside a second side surface of the first gate electrode on a side opposed to the first side surface;

a semiconductor region which is formed in the first projecting unit beside the sidewall spacer;

a first insulating film which is formed over the semiconductor region;

a first interlayer insulating film which is formed over the first insulating film;

a second interlayer insulating film which is formed over the first interlayer insulating film and the first gate electrode; and

a plug which is formed in the second interlayer insulating film, the first interlayer insulating film, and the first insulating film, in a manner to reach the semiconductor region,

wherein a cap film is formed between the first gate electrode and the second interlayer insulating film,

wherein the plug is positioned also right over the cap film, and

wherein the first interlayer insulating film and the second interlayer insulating film are formed from a material which differs from that of the first insulating film and the cap film.

2. The semiconductor device according to claim 1,

wherein the first gate insulating film is formed along a bottom surface and a side surface of the first gate electrode,

wherein the first gate insulating film is formed between the cap film and the second gate insulating film, and

wherein the first gate insulating film is formed from a material which differs from that of the first insulating film and the cap film.

3. The semiconductor device according to claim 2,

wherein the first gate insulating film and the second gate insulating film are formed between the cap film and the second gate electrode.

4. The semiconductor device according to claim 3,

wherein a silicide layer is formed over the second gate electrode.

5. The semiconductor device according to claim 2,

wherein the first interlayer insulating film and the second interlayer insulating film are formed from silicon oxide,

wherein the first insulating film and the cap film are formed from silicon nitride, and

wherein the first gate insulating film is formed from metal oxide.

6. The semiconductor device according to claim 5,

wherein the metal oxide is an oxide film including hafnium, an oxide film including aluminum, an oxide film including zirconium, or an oxide film including tantalum.

7. The semiconductor device according to claim 1,

wherein the second gate insulating film has a charge storage layer,

wherein the first gate electrode, the first gate insulating film, the second gate electrode, the second gate insulating film, and the semiconductor region form a non-volatile memory.

8. The semiconductor device according to claim 7,

wherein two non-volatile memories which are adjacent to each other are formed symmetrically about the semiconductor region, and

wherein the plug is positioned right over the cap film of each of the adjacent non-volatile memories.

9. A manufacturing method for a semiconductor device, comprising the steps of:

(a) preparing a semiconductor substrate;

(b) retreating a part of the semiconductor substrate, thereby forming a first projecting unit, which is apart of the semiconductor substrate, projects from an upper surface of the semiconductor substrate, and extends in a first direction along a main surface of the semiconductor substrate;

(c) forming a dummy gate electrode over the upper surface and a side surface of the first projecting unit through a first insulating film;

(d) forming a second gate insulating film over the upper surface and the side surface of the first projecting unit and over a first side surface of the dummy gate electrode;

(e) forming a second gate electrode over the upper surface and the side surface of the first projecting unit and over a second side surface of the dummy gate electrode on a side opposed to the first side surface, through the second gate insulating film;

(f) forming a sidewall spacer over the upper surface of the first projecting unit and over the second side surface of the dummy gate electrode, after the step (e);

(g) forming a semiconductor region in the first projecting unit beside the sidewall spacer, using ion implantation;

(h) forming a second insulating film over the semiconductor region;

(i) forming a first interlayer insulating film over the second insulating film;

(j) forming an opening for exposing the first projecting unit between the sidewall spacer and the second gate insulating film, by removing the dummy gate electrode and the first insulating film, after the step (i);

(k) forming a first gate insulating film in the opening;

(l) embedding a first gate electrode in the opening, through the first gate insulating film;

(m) retreating an upper surface of the first gate electrode;

(n) forming a cap film over the first gate electrode in a manner to fill the opening, after the step (m);

(o) forming a second interlayer insulating film over the first interlayer insulating film and the cap film, after the step (n); and

(p) forming a contact hole reaching the semiconductor region, in the second interlayer insulating film, the first interlayer insulating film, and the second insulating film,

wherein the contact hole is positioned right above the cap film, and

wherein the first interlayer insulating film and the second interlayer insulating film are formed from a material which differs from that of the second insulating film and the cap film.

10. The manufacturing method for a semiconductor device, according to claim 9,

wherein the first gate insulating film is formed between the cap film and the second gate electrode, and

wherein the first gate insulating film is formed from a material which differs from that of the second insulating film and the cap film.

11. The manufacturing method for a semiconductor device, according to claim 10,

wherein the first gate insulating film and the second gate insulating film are formed between the cap film and the second gate electrode.

12. The manufacturing method for a semiconductor device, according to claim 11,

wherein a silicide layer is formed over the second gate electrode.

13. The manufacturing method for a semiconductor device, according to claim 9,

wherein, in the step (p), the second insulating film and the cap film serve as an etching stopper, when etching the second interlayer insulating film and the first interlayer insulating film.

14. The manufacturing method for a semiconductor device, according to claim 13,

wherein the step (p) includes the steps of

(P1) etching the second interlayer insulating film and the first interlayer insulating film,

(P2) after the step (P1), etching a part of the cap film, and at a same time etching the second insulating film to form the contact hole reaching the semiconductor region,

wherein, in the step (P1), the second insulating film and the cap film serve as an etching stopper, and

wherein, in the step (P2), the first gate insulating film serves as an etching stopper.

15. The manufacturing method for a semiconductor device, according to claim 11,

wherein the first and second interlayer insulating films are formed from silicon oxide, and

wherein the second insulating film and the cap film are formed from silicon nitride, and

wherein the first gate insulating film is formed from metal oxide.

16. The manufacturing method for a semiconductor device, according to claim 15,

wherein the metal oxide is an oxide film including hafnium, an oxide film including aluminum, an oxide film including zirconium, or an oxide film including tantalum.

17. The manufacturing method for a semiconductor device, according to claim 9,

wherein the second gate insulating film has a charge storage layer, and

wherein the first gate electrode, the first gate insulating film, the second gate electrode, the second gate insulating film, and the semiconductor region form a non-volatile memory.

18. The manufacturing method for a semiconductor device, according to claim 17,

wherein two non-volatile memories which are adjacent to each other are formed symmetrically about the semiconductor region, and

wherein the contact hole is positioned right over the cap film formed over the first gate electrode of each of the adjacent non-volatile memories.