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CN-122018078-A - Semiconductor structure and manufacturing method thereof

CN122018078ACN 122018078 ACN122018078 ACN 122018078ACN-122018078-A

Abstract

The application provides a semiconductor structure and a manufacturing method thereof, wherein the method comprises the steps of providing a substrate, and sequentially forming a sacrificial layer and a mask layer on the substrate; etching the mask layer to form two opening patterns, wherein the cross section size of the first opening pattern is larger than that of the second opening pattern, performing ion implantation by taking the mask layer as a mask, forming a sacrificial treatment layer at the bottom of the first opening pattern, performing first etching by taking the mask layer as a mask, removing the sacrificial treatment layer, performing second etching by taking the mask layer as a mask, and forming a first groove and a second groove, the cross section size of the first groove is larger than that of the second groove, and the depth of the first groove is larger than that of the second groove. According to the application, two grooves with different cross section sizes and depths are formed in the same photoetching process, so that the process steps are reduced, the number of masks is reduced, and the cost is reduced.

Inventors

  • LIU JINLIN
  • PENG JIE

Assignees

  • 芯恩（青岛）集成电路有限公司

Dates

Publication Date
20260512
Application Date
20260213

Claims (10)

  1. 1. A method of fabricating a semiconductor structure, comprising: Providing a substrate, and sequentially forming a sacrificial layer and a mask layer on the substrate; Etching the mask layer to form two opening patterns exposing the sacrificial layer, wherein the cross section size of the first opening pattern is larger than that of the second opening pattern; performing ion implantation by taking the mask layer as a mask, and adjusting the ion implantation angle to enable ions to be implanted into the sacrificial layer at the bottom of the first opening pattern to form a sacrificial treatment layer, wherein ions cannot be implanted into the sacrificial layer at the bottom of the second opening pattern; Performing first etching by taking the mask layer as a mask, wherein the etching selection ratio of the sacrificial treatment layer to the sacrificial layer in the etching is greater than 10:1, so as to remove the sacrificial treatment layer at the bottom of the first opening pattern, forming an initial groove at the bottom of the first opening pattern, and And performing second etching by taking the mask layer as a mask, removing the substrate with partial depths of the bottoms of the first opening pattern and the second opening pattern, forming a first groove at the bottom of the first opening pattern, forming a second groove at the bottom of the second opening pattern, wherein the cross section size of the first groove is larger than that of the second groove, and the depth of the first groove is larger than that of the second groove.
  2. 2. The method of claim 1, wherein the base comprises a support substrate, a buried oxide layer, and a material layer stacked in sequence, and the first trench and the second trench are formed in the material layer.
  3. 3. The method of claim 1, wherein the first etching removes the sacrificial layer and the mask layer having a partial thickness of the sidewalls of the first and second patterns.
  4. 4. The method of manufacturing a semiconductor structure according to claim 3, wherein a cross-sectional dimension of the first opening pattern is smaller than a cross-sectional dimension of the first trench, and a cross-sectional dimension of the second opening pattern is smaller than a cross-sectional dimension of the second trench.
  5. 5. The method of claim 1, wherein the material of the sacrificial layer comprises silicon, the ion implanted ions comprise oxygen ions, the material of the sacrificial layer comprises silicon dioxide, and/or the material of the mask layer comprises silicon nitride.
  6. 6. The method of fabricating a semiconductor structure according to claim 5, wherein the density of oxygen atoms required to form the silicon dioxide having a thickness d is (2xρ_sio 2 ×N_A/M_SiO 2 ) ×d, wherein ρ_sio 2 is the density of silicon dioxide, n_a is the avogaldel-crafts constant, and m_sio 2 is the molar mass of silicon dioxide.
  7. 7. The method of claim 1, further comprising forming a buffer layer on the substrate before forming the sacrificial layer on the substrate, wherein the sacrificial layer is formed on the buffer layer.
  8. 8. The method of manufacturing a semiconductor structure according to claim 1, further comprising etching the substrate after the first trench and the second trench are formed, wherein a third trench is formed in the substrate, a cross-sectional dimension of the third trench is smaller than a cross-sectional dimension of the first trench, the cross-sectional dimension of the third trench is larger than a cross-sectional dimension of the second trench, and a depth of the third trench is smaller than a depth of the first trench, and a depth of the third trench is larger than a depth of the second trench.
  9. 9. The method of claim 1, wherein etching the mask layer to form two opening patterns exposing the sacrificial layer comprises: forming a photoresist layer on the mask layer; exposing and developing the photoresist layer to form a patterned photoresist layer, wherein the patterned photoresist layer exposes a first opening pattern area and a second opening pattern area of the mask layer; Etching the mask layer by using the patterned photoresist layer as a mask until the sacrificial layer is exposed to form the first opening pattern and the second opening pattern, and And removing the patterned photoresist layer.
  10. 10. A semiconductor structure fabricated by the method of any of claims 1 to 9, the semiconductor structure comprising: A substrate; A sacrificial layer on the substrate; a mask layer on the sacrificial layer, and And the first groove and the second groove penetrate through the mask layer and the sacrificial layer and extend into the substrate, wherein the cross section size of the first groove is larger than that of the second groove, and the depth of the first groove is larger than that of the second groove.

Description

Semiconductor structure and manufacturing method thereof Technical Field The present application relates to the field of semiconductor integrated circuits, and more particularly, to a semiconductor structure and a method for fabricating the same. Background In order to meet the signal input and output requirements of various devices in the fabrication of silicon optical chips, it is necessary to prepare optical waveguides (waveguide, WG) of various sizes, and the sizes and depths of the different optical waveguides are different. Because the structural parameters of each optical waveguide have large difference, especially the critical dimension and the etching depth are different, the prior art generally depends on a plurality of independent photomasks, and the manufacture of different optical waveguide structures is respectively finished through a plurality of photoetching and etching steps. The preparation method of the multiple photomask and the multiple etching has complex process steps and high cost. Disclosure of Invention The application aims to provide a semiconductor structure and a manufacturing method thereof, which can reduce the process steps, reduce the number of required masks and reduce the cost. In order to solve the above technical problem, according to a first aspect of the present application, there is provided a method for manufacturing a semiconductor structure, including the steps of: Providing a substrate, and sequentially forming a sacrificial layer and a mask layer on the substrate; Etching the mask layer to form two opening patterns exposing the sacrificial layer, wherein the cross section size of the first opening pattern is larger than that of the second opening pattern; performing ion implantation by taking the mask layer as a mask, and adjusting the ion implantation angle to enable ions to be implanted into the sacrificial layer at the bottom of the first opening pattern to form a sacrificial treatment layer, wherein ions cannot be implanted into the sacrificial layer at the bottom of the second opening pattern; Performing first etching by taking the mask layer as a mask, wherein the etching selection ratio of the sacrificial treatment layer to the sacrificial layer in the etching is greater than 10:1, so as to remove the sacrificial treatment layer at the bottom of the first opening pattern, forming an initial groove at the bottom of the first opening pattern, and And performing second etching by taking the mask layer as a mask, removing the substrate with partial depths of the bottoms of the first opening pattern and the second opening pattern, forming a first groove at the bottom of the first opening pattern, forming a second groove at the bottom of the second opening pattern, wherein the cross section size of the first groove is larger than that of the second groove, and the depth of the first groove is larger than that of the second groove. Optionally, the substrate includes a support substrate, an oxygen-buried layer, and a material layer stacked in sequence, and the first trench and the second trench are formed in the material layer. Optionally, in the first etching, the sacrificial treatment layer is removed, and the mask layer with partial thicknesses of the sidewalls of the first opening pattern and the second opening pattern is also removed. Optionally, the cross-sectional dimension of the first opening pattern is smaller than the cross-sectional dimension of the first trench, and the cross-sectional dimension of the second opening pattern is smaller than the cross-sectional dimension of the second trench. Optionally, the material of the sacrificial layer comprises silicon, the ion implanted ions comprise oxygen ions, the material of the sacrificial treatment layer comprises silicon dioxide, or/and the material of the mask layer comprises silicon nitride. Alternatively, the density of oxygen atoms required to form a silicon dioxide having a thickness d is (2Xρ_SiO 2×N_A/M_SiO2) x d, where ρ_SiO 2 is the density of silicon dioxide, N_A is the AvoGalileo constant and M_SiO 2 is the molar mass of silicon dioxide. Optionally, before forming the sacrificial layer on the substrate, forming a buffer layer on the substrate, wherein the sacrificial layer is formed on the buffer layer. Optionally, after the first groove and the second groove are formed, etching the substrate to form a third groove in the substrate, wherein the cross-sectional dimension of the third groove is smaller than that of the first groove, the cross-sectional dimension of the third groove is larger than that of the second groove, the depth of the third groove is smaller than that of the first groove, and the depth of the third groove is larger than that of the second groove. Optionally, the method for etching the mask layer to form two opening patterns exposing the sacrificial layer includes: forming a photoresist layer on the mask layer; exposing and developing the photoresist layer to form a patterne