CN-122018048-A - Light-operated super-surface structure and manufacturing method thereof

Abstract

The invention discloses a light-operated super-surface structure and a manufacturing method thereof, wherein the light-operated super-surface structure comprises a composite dielectric layer, the composite dielectric layer comprises a silicon nitride carbide layer, an oxide layer and a silicon nitride layer which are stacked from bottom to top, a first metal railing consists of a base and a metal strip, wherein the first metal railing embedded in the silicon oxide layer and the silicon nitride carbide layer is defined as a base, the first metal railing embedded in the silicon nitride layer and protruding above the silicon nitride layer is defined as a metal strip, the width of the base in the silicon oxide layer is continuously and gradually increased towards the silicon nitride carbide layer, a second metal railing is arranged on one side of the first metal railing, the second metal railing and the first metal railing have the same structure, a gap is arranged between the first metal railing and the second metal railing, and a plurality of liquid crystals fill the gap.

Inventors

• GUO ZHIWEI
• QIU CHONGYI

Assignees

• 联华电子股份有限公司

Dates

Publication Date

20260512

Application Date

20241126

Priority Date

20241111

Claims (18)

1. 1. A light-operated supersurface (Light Control Metasurface, LCM) structure comprising: a composite dielectric layer, wherein the composite dielectric layer comprises a silicon carbide nitride (nitrogen doped silicon caribe) layer, an oxide layer, and a silicon nitride layer stacked from bottom to top; A first metal rail, wherein the first metal rail is composed of a base and a metal bar, the first metal rail embedded in the silicon oxide layer and the silicon carbide nitride layer is defined as the base, the first metal rail embedded in the silicon nitride layer and protruding above the silicon nitride layer is defined as the metal bar, and the width of the base in the silicon oxide layer continuously and gradually increases along the direction towards the silicon carbide nitride layer; The second metal railing is arranged on one side of the first metal railing, and the second metal railing and the first metal railing have the same structure; a gap arranged between the first metal railing and the second metal railing, and And a plurality of liquid crystals filling the gaps.
2. 2. The light control super surface structure of claim 1, wherein the metal strip has a top surface, and the width of the metal strip gradually decreases along the top surface toward the base.
3. 3. The light-operated subsurface structure as described in claim 1 wherein the metal strip comprises sidewalls, the sidewalls adjacent to the top surface having corners.
4. 4. The optically controlled subsurface structure of claim 1, further comprising: A first dielectric layer disposed under the composite dielectric layer, and The reflecting layer is embedded in the first dielectric layer, and is positioned right below the first metal railing and the second metal railing.
5. 5. The optically controlled subsurface structure of claim 4, further comprising: A second dielectric layer disposed over the composite dielectric layer, and And the copper wire structure is buried in the second dielectric layer, the composite dielectric layer and the first dielectric layer, wherein the copper wire structure comprises a first wire, a first plug and a second wire which are stacked from bottom to top.
6. 6. The light-operated subsurface structure of claim 5, wherein the second conductive line is embedded in the second dielectric layer and the composite dielectric layer, the width of the second conductive line in the silicon oxide layer continuously gradually increases in a direction toward the silicon carbide nitride layer, and the end of the second conductive line is located in the silicon carbide nitride layer.
7. 7. The optically controlled subsurface structure as described in claim 5 wherein the upper surface of the first conductive line and the upper surface of the reflective layer are level.
8. 8. The light-operated subsurface structure of claim 1 further comprising a protective layer in contact with the metal strips protruding above the silicon nitride layer, wherein the liquid crystals contact the protective layer.
9. 9. The optically controlled subsurface structure as described in claim 1 wherein the oxide layer contacts the silicon carbide nitride layer and the silicon nitride layer.
10. 10. A method of fabricating a light-operated subsurface (Light Control Metasurface, LCM) structure comprising: Providing a first dielectric layer, a composite dielectric layer and a second dielectric layer which are stacked from bottom to top, wherein the composite dielectric layer comprises a silicon nitride carbide (nitrogen doped silicon caribe) layer, an oxide layer and a silicon nitride layer which are stacked from bottom to top; forming a first trench embedded in the second dielectric layer and the silicon nitride layer; etching the silicon oxide layer by using a first etchant after forming the first trench to extend the bottom of the first trench into the silicon oxide layer; After the isotropic etching process, performing an anisotropic etching process with a second etchant to etch the silicon carbide nitride layer such that the bottom of the first trench extends into the silicon carbide nitride layer; forming a diffusion barrier layer covering the first trench after the anisotropic etching process; after forming the diffusion barrier layer, forming a metal layer to fill the first trench, and Removing all of the second dielectric layer and the diffusion barrier layer in the second dielectric layer to form voids, and A plurality of liquid crystals are provided to fill the gap.
11. 11. The method of claim 10, wherein the step of embedding the first trench into the silicon nitride layer comprises etching the silicon nitride layer with a third etchant using an anisotropic etching process.
12. 12. The method of claim 11, wherein the third etchant comprises hexafluorobutadiene (C 4 F 6 ).
13. 13. The method of claim 10, wherein the first etchant comprises carbon tetrafluoride (CF 4 ) and the second etchant comprises trifluoromethane (CHF 3 ).
14. 14. The method of claim 10, further comprising forming a first conductive line, a first plug, and a second conductive line stacked from bottom to top, wherein the first conductive line and the first plug are embedded in the first dielectric layer, and the second conductive line is embedded in the composite dielectric layer and the second dielectric layer.
15. 15. The method of making a light-operated subsurface structure as described in claim 14, further comprising: forming a second trench embedded in the second dielectric layer and the silicon nitride layer simultaneously while forming the first trench; Etching the silicon oxide layer by using the first etchant after forming the second trench so that the bottom of the second trench extends into the silicon oxide layer; after the isotropic etching process, etching the silicon carbide nitride layer by the second etchant to extend the bottom of the second trench into the silicon carbide nitride layer; Forming a diffusion barrier layer covering the second trench after the anisotropic etching process, and After the diffusion barrier layer is formed, the metal layer is formed to fill the second trench to form the second conductive line.
16. 16. The method of claim 15, wherein the diffusion barrier layer in the second trench contacts the first plug.
17. 17. The method of claim 14, further comprising simultaneously forming a reflective layer and the first conductive line embedded in the first dielectric layer, wherein the reflective layer is located directly under the first trench, and an upper surface of the first conductive line is aligned with an upper surface of the reflective layer.
18. 18. The method of claim 10, wherein the opening of the first trench is enlarged during the isotropic etching process.

Description

Light-operated super-surface structure and manufacturing method thereof Technical Field The present invention relates to a light-operated super surface structure and a manufacturing method thereof, and more particularly, to a manufacturing method for preventing metal rail (rail) in a light-operated super surface structure from tilting during etching. Background Optical radar is a sensing technology that emits a low power, eye-safe laser to measure the time required for the laser to complete a round trip between the sensor and the target. Optical radars can be used in home security systems, barcode scanners and face recognition systems, and their use in fully automated driving is also attractive. Unlike radar and sonar, optical radar provides high-resolution three-dimensional data, making it an important tool for the automotive, geological and agricultural industries. The optically controlled subsurface (Light Control Metasurface, LCM) is a semiconductor chip that deflects laser pulses based on the principle of light refraction of the material. The technology is used for the optical radar technology, can improve the sensing capability of the optical radar technology, is beneficial to the characteristics of semiconductor manufacture, and reduces the manufacturing cost. Disclosure of Invention In view of this, the present invention provides a method for fabricating an optically controlled super-surface structure, so as to improve the yield of the optically controlled super-surface structure. According to a preferred embodiment of the present invention, an optically controlled super-surface structure comprises a composite dielectric layer, wherein the composite dielectric layer comprises a silicon carbide nitride (nitrogen doped silicon caribe) layer, an oxide layer and a silicon nitride layer stacked from bottom to top, a first metal rail is composed of a base and a metal bar, wherein the first metal rail embedded in the silicon carbide layer and the silicon carbide nitride layer is defined as a base, the first metal rail embedded in the silicon nitride layer and protruding above the silicon carbide layer is defined as a metal bar, the metal bar has a top surface, the width of the metal bar gradually decreases along the direction of the top surface toward the base, the width of the base in the silicon oxide layer continuously gradually increases along the direction toward the silicon carbide nitride layer, a second metal rail is disposed on one side of the first metal rail, the second metal rail and the first metal rail have the same structure, a gap is disposed between the first metal rail and the second metal rail, and a plurality of liquid crystals fill the gap. According to another preferred embodiment of the present invention, a method for fabricating an optically controlled super-surface structure includes providing a first dielectric layer, a composite dielectric layer and a second dielectric layer stacked from bottom to top, wherein the composite dielectric layer includes a silicon carbide nitride layer, an oxide layer and a silicon nitride layer stacked from bottom to top, then forming a first trench embedded in the second dielectric layer and the silicon nitride layer, etching the silicon oxide layer with a first etchant to extend the bottom of the first trench into the silicon oxide layer after forming the first trench, etching the silicon carbide layer with a second etchant to extend the bottom of the first trench into the silicon carbide layer with an anisotropic etching process after the isotropic etching process, forming a diffusion barrier layer to cover the first trench after the anisotropic etching process, forming a metal layer to fill the first trench after the diffusion barrier layer is formed, finally removing all of the second dielectric layer and the diffusion barrier layer in the second dielectric layer to form a void, and finally providing a plurality of liquid crystal filled voids. In order to make the above objects, features and advantages of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below. The following preferred embodiments and drawings are, however, for purposes of illustration and description only and are not intended to limit the scope of the invention. Drawings Fig. 1 to 7 are schematic views of a method for fabricating an optically controlled super-surface structure according to a preferred embodiment of the invention. Symbol description 10 First dielectric layer 10A silicon oxide layer 10B silicon carbide nitride layer 12 Composite dielectric layer 12A silicon carbide nitride layer 12B oxide layer 12C silicon nitride layer 14 Second dielectric layer 16 First conductor 18 First plug 20 First groove 20A corner 22 Second groove 22A corner 24 Diffusion barrier layer 26 Metal layer 28 Mask layer 30 Protective layer 32 Liquid crystal 34A first metal rail 34B second metal rail 36 Base 38 Metal strip 40 Copper w