Method for manufacturing embedded memory using high-K-metal-gate (HKMG) technology

Patent metadata

Field	Value
Publication number	US-10128259-B1
Application number	US-201715651403-A
Country	US
Kind code	B1
Filing date	Jul 17, 2017
Priority date	Jul 17, 2017
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A method for manufacturing embedded memory using high-κ-metal-gate (HKMG) technology is provided. A gate stack is formed on a semiconductor substrate. The gate stack comprises a charge storage film and a control gate overlying the charge storage film. The control gate includes a first material. A gate layer is formed of the first material, and is formed covering the semiconductor substrate and the gate stack. The gate layer is recessed to below a top surface of the gate stack, and subsequently patterned to form a select gate bordering the control gate and to form a logic gate spaced from the select and control gates. An ILD layer is formed between the control, select, and logic gates, and with a top surface that is even with top surfaces of the control, select, and logic gates. The control, select, or logic gate is replaced with a new gate of a second material.

First claim

What is claimed is:

1. A method for manufacturing an integrated circuit (IC), the method comprising:
forming a gate stack on a semiconductor substrate, wherein the gate stack comprises a charge storage film and a control gate overlying the charge storage film, and wherein the control gate includes a first material;
forming a gate layer covering the semiconductor substrate and the gate stack, wherein the gate layer includes the first material;
recessing a top surface of the gate layer to below a top surface of the gate stack;
patterning the gate layer to form a select gate, and to further form a logic gate spaced from the select and control gates;
forming an interlayer dielectric (ILD) layer laterally between the control, select, and logic gates, wherein the ILD layer is formed with a top surface that is even with top surfaces respectively of the control, select, and logic gates; and
replacing the control, select, or logic gate with a new gate, wherein the new gate includes a second material different than the first material.

2. The method according to claim 1 , further comprising:
replacing the control, select, and logic gates respectively with new gates, wherein the new gates include the second material.

3. The method according to claim 1 , wherein the first material includes polysilicon, and wherein the second material includes metal.

4. The method according to claim 1 , wherein the charge storage film includes an oxide-nitride-oxide (ONO) film.

5. The method according to claim 1 , wherein the recessing comprises:
forming an anti reflective coating (ARC) layer covering the gate layer; and
simultaneously etching the ARC layer and the gate layer until the top surface of the gate layer has been recessed to the control gate and the ARC layer has been removed.

6. The method according to claim 5 , wherein the recessing further comprises:
forming a logic hard mask on the gate layer, wherein the logic hard mask covers a logic region of the semiconductor substrate on which the logic gate is formed, wherein the select and control gates are formed on a memory region of the semiconductor substrate that is laterally spaced from the logic region, wherein the ARC layer is formed covering the logic hard mask, and wherein the simultaneous etching stops on the logic hard mask.

7. The method according to claim 1 , wherein the patterning of the gate layer comprises:
forming a dummy gate hard mask layer covering the gate layer; and
performing an etch into the dummy gate hard mask layer and the gate layer to form the select and logic gates, and to further form a logic gate hard mask and a memory gate hard mask, wherein the logic gate hard mask overlies the logic gate, and wherein the memory gate hard mask overlies the control and select gates.

8. The method according to claim 1 , wherein the replacing replaces the control, select, or logic gate with both the new gate and a high κ dielectric layer underlying the new gate.

9. The method according to claim 1 , wherein the replacing comprises:
performing an etch into the control, select, or logic gate to remove the control, select, or logic gate, and to form an opening in place of the control, select, or logic gate;
forming a high κ dielectric layer along a bottom surface of the opening;
forming a metal layer filling the opening over the high κ dielectric layer; and
performing a planarization into the metal layer to the top surface of the ILD layer, such that the new gate is formed in the opening and from the metal layer.

10. An integrated circuit (IC) comprising:
a semiconductor substrate;
a memory cell on the semiconductor substrate, wherein the memory cell comprises a pair of source/drain regions in the semiconductor substrate, and further comprises a select gate, a charge storage film, a high κ control gate dielectric layer, and a control gate, wherein the source/drain regions define a selectively-conductive channel extending continuously from one of the source/drain regions to another one of the source/drain regions, wherein the select gate and the charge storage film are on the selectively-conductive channel, wherein the high κ control gate dielectric layer overlies the charge storage film and has a U-shaped cross section, and wherein the control gate is metal and overlies the high κ control gate dielectric layer; and
a logic device on the semiconductor substrate, laterally spaced from the memory cell, wherein the logic device comprises a logic gate.

11. The IC according to claim 10 , wherein the charge storage film includes an oxide-nitride-oxide (ONO) film.

12. The IC according to claim 10 , wherein the memory cell further comprises a high κ select gate dielectric layer, wherein the select gate overlies the high κ select gate dielectric layer, and wherein the select gate is metal.

13. The IC according to claim 10 , wherein the memory cell further comprises:
a pair of control gate sidewall spacers respectively on opposite sides of the control gate, wherein the control gate sidewall spacers both directly overlie the charge storage film; and
an inter-gate spacer between the select gate and the control gate sidewall spacers, wherein the inter-gate spacer laterally and directly contacts both the charge storage film and one of the control gate sidewall spacers.

14. The IC according to claim 13 , wherein the memory cell further comprises a high κ select gate dielectric layer, wherein the select gate overlies and contacts the high κ select gate dielectric layer, and where the inter-gate spacer laterally contacts the high κ select gate dielectric layer.

15. The IC according to claim 13 , wherein the control gate sidewall spacers laterally contact the high κ control gate dielectric layer, and wherein the inter-gate spacer laterally contacts the select gate.

16. The IC according to claim 10 , further comprising a second memory cell on the semiconductor substrate, laterally spaced from the logic device and the memory cell, wherein the second memory cell comprises a second pair of source/drain regions in the semiconductor substrate, and further comprises a second select gate, a second charge storage film, and a second control gate, wherein the source/drain regions of the second pair define a second selectively-conductive channel extending continuously respectively from and to the source/drain regions of the second pair, wherein the second select gate and the second charge storage film are on the second selectively-conductive channel, and wherein the second control gate overlies the second charge storage film.

17. A method for manufacturing an integrated circuit (IC), the method comprising:
forming a pair of gate stacks on a memory region of a semiconductor substrate, wherein the gate stacks each comprise an oxide-nitride-oxide (ONO) charge storage film and a polysilicon control gate overlying the ONO charge storage film;
forming a polysilicon gate layer covering and conformally lining the semiconductor substrate and the gate stacks;
forming an antireflective coating (ARC) layer covering the polysilicon gate layer;
simultaneously etching the ARC layer and the polysilicon gate layer until the ARC layer has been removed and a top surface of the polysilicon gate layer has been recessed to below top surfaces of the gate stacks;
patterning the gate layer to form a pair of polysilicon select gates on the memory region of the semiconductor substrate, respectively bordering the polysilicon control gates of the gate stacks, and to further form a polysilicon logic gate on a logic region of the semiconductor substrate that is spaced from t

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Yang Tsung-Yu
• Huang Chung-Jen
• Wu Yun-Chi

Classifications

• H10P95/062

  involving a dielectric removal step · CPC title

• H10P76/2043

  using an anti-reflective coating · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P50/73

  using masks for insulating materials · CPC title

• H01L27/11526

  Electricity · mapped topic