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CN-117004949-B - Etching method

CN117004949BCN 117004949 BCN117004949 BCN 117004949BCN-117004949-B

Abstract

The application provides an etching method, which comprises the steps of providing a structure to be etched, wherein the structure to be etched comprises an insulating layer, a metal layer and a patterned photoresist layer, the metal layer and the patterned photoresist layer are sequentially arranged on the insulating layer, the photoresist layer is used as a mask, the metal layer is etched at a first etching angle by utilizing an inert gas ion beam to obtain an etching groove, a metal deposition layer is formed on the side wall surface of the photoresist layer in the etching process, the photoresist layer and the metal deposition layer are etched at a second etching angle by utilizing a mixed gas ion beam to remove the metal deposition layer, the mixed gas comprises inert gas and reaction gas, the reaction gas can react with the photoresist layer, the photoresist layer can be consumed, the depth-to-width ratio of the etching groove is reduced, the mixed gas is beneficial to etching the metal deposition layer by utilizing the mixed gas ion beam, the second etching angle is larger than the first etching angle, the metal deposition layer can be completely removed, the damage to the insulating layer can be reduced, and the yield of a metal electrode can be improved.

Inventors

  • WANG YAO
  • Peng Taiyan
  • YANG YUXIN
  • JIANG ZHONGYUAN
  • XU KAIDONG

Assignees

  • 江苏鲁汶仪器股份有限公司

Dates

Publication Date
20260508
Application Date
20220429

Claims (8)

  1. 1. An etching method, comprising: Providing a structure to be etched, wherein the structure to be etched comprises an insulating layer, a metal layer and a patterned photoresist layer, wherein the metal layer and the patterned photoresist layer are sequentially arranged on the insulating layer; Etching the metal layer at a first etching angle by using the photoresist layer as a mask and utilizing an inert gas ion beam to obtain an etching groove; Etching the photoresist layer and the metal deposition layer at a second etching angle by using a mixed gas ion beam to remove the metal deposition layer, wherein the mixed gas comprises inert gas and reactive gas, the second etching angle is larger than the first etching angle, the inert gas and the reactive gas jointly act on the metal deposition layer in the etching process, the inert gas modifies the metal deposition layer through physical bombardment, and the reactive gas reacts with the photoresist layer while assisting in modifying the metal deposition layer to play a role of reactive ion etching, so that the consumption of the photoresist layer is accelerated, the depth-to-width ratio of the etching groove is reduced, and repeated deposition of metal on the side wall is avoided to remove the metal deposition layer; The range of the second etching angle is 45-75 degrees, and the range of the first etching angle is 0-20 degrees.
  2. 2. The method of claim 1, wherein the etched trench partially penetrates the metal layer, and wherein the metal layer at the bottom of the etched trench is removed when the photoresist layer and the metal deposition layer are etched using the mixed gas ion beam at a second etching angle.
  3. 3. The method of claim 1, wherein the reactant gas is oxygen, nitric oxide, carbon monoxide, carbon dioxide, or a fluorine/chlorine based gas.
  4. 4. The method of claim 1, wherein the inert gas has a flow ratio in the mixed gas of greater than or equal to 0.5.
  5. 5. The method of claim 1, wherein the second etch angle ranges from 60 ° to 75 °.
  6. 6. The method of any one of claims 1-5, wherein the metal layer material is gold, silver, platinum, or copper.
  7. 7. The method according to any one of claims 1 to 5, wherein the inert gas flow rate in the mixed gas is 15 to 60sccm, and the reactive gas flow rate in the mixed gas is 2 to 20sccm.
  8. 8. The method according to any one of claims 1 to 5, wherein the beam current voltage of the inert gas ion beam and the mixed gas ion beam is 100V to 600V, and the particle acceleration voltage of the inert gas ion beam and the mixed gas ion beam is 50V to 100V.

Description

Etching method Technical Field The application relates to the technical field of semiconductor processes, in particular to an etching method. Background In metal electrode fabrication, the choice of metal layer material takes into account the performance requirements of the device, including resistivity, adhesion characteristics, deposition conditions of the thin film, and selectivity issues. Metals such as gold, silver and platinum provide significant performance characteristics such as having excellent characteristics of low resistivity, high chemical stability, high melting point, low surface work function, good ohmic contact with other metals, etc. Therefore, gold, silver, platinum, and the like are widely used as metal layers in the manufacture of electrodes. The metal etching is generally classified into wet etching and dry etching, and as the feature resolution gradually decreases, the dry etching is attracting attention due to its high transfer accuracy. The most important advantage of dry etching in a plasma environment for etching metals compared to wet etching is that lateral undercutting can be avoided and the roughness is lower, so that the metal layer has fewer dents. In the prior art, in the process of Etching metal in a plasma environment, the problem of redeposition of the side wall can be caused, and an Ion Beam Etching technology (IBE) can be used for removing residues of the side wall, but under a high aspect ratio structure, the incidence angle of the Ion Beam is limited, the advantages of the Ion Beam are difficult to fully develop, the residues of the side wall cannot be completely removed, and the underlying insulating layer is easy to excessively etch, so that the yield of the metal electrode is affected. Disclosure of Invention Accordingly, the present application is directed to an etching method capable of completely removing a metal deposition layer remained on a sidewall with less damage to an insulating layer. The specific scheme is as follows: In a first aspect, the present application provides an etching method, including: Providing a structure to be etched, wherein the structure to be etched comprises an insulating layer, a metal layer and a patterned photoresist layer, wherein the metal layer and the patterned photoresist layer are sequentially arranged on the insulating layer; Etching the metal layer at a first etching angle by using the photoresist layer as a mask and utilizing an inert gas ion beam to obtain an etching groove; and etching the photoresist layer and the metal deposition layer by using a mixed gas ion beam at a second etching angle to remove the metal deposition layer, wherein the mixed gas comprises inert gas and reaction gas, and the second etching angle is larger than the first etching angle. Optionally, the etching groove partially penetrates through the metal layer, and when the photoresist layer and the metal deposition layer are etched by using the mixed gas ion beam at a second etching angle, the metal layer at the bottom of the etching groove is removed. Optionally, the reaction gas is oxygen, nitric oxide, carbon monoxide, carbon dioxide or a fluorine/chlorine based gas. Optionally, the flow ratio of the inert gas in the mixed gas is greater than or equal to 0.5. Optionally, the second etching angle ranges from 45 ° to 75 °. Optionally, the second etching angle ranges from 60 ° to 75 °. Optionally, the first etching angle ranges from 0 ° to 20 °. Optionally, the metal layer material is gold, silver, platinum or copper. Optionally, the flow rate of the inert gas in the mixed gas is 15-60sccm, and the flow rate of the reaction gas in the mixed gas is 2-20sccm. Optionally, the beam current voltage of the inert gas ion beam and the mixed gas ion beam is 100V-600V, and the particle acceleration voltage of the inert gas ion beam and the mixed gas ion beam is 50V-100V. The embodiment of the application provides an etching method, which comprises the steps of firstly providing a structure to be etched, wherein the structure to be etched comprises an insulating layer, a metal layer and a patterned photoresist layer which are sequentially arranged on the insulating layer, then etching the metal layer by using an inert gas ion beam at a first etching angle with the photoresist layer as a mask to obtain an etching groove, forming a metal deposition layer on the side wall surface of the photoresist layer in the etching process, wherein the metal deposition layer seriously affects the subsequent process, then etching the photoresist layer and the metal deposition layer by using a mixed gas ion beam at a second etching angle to remove the metal deposition layer, the mixed gas comprises inert gas and reactive gas, the reactive gas can react with the photoresist layer, the photoresist layer can be consumed, the depth-width ratio of the etching groove is reduced, the repeated deposition of metal on the side wall is avoided, the mixed gas ion beam is beneficial to e