# US 9,435,038 B2 · Ion implant assisted metal etching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,038 B2 - Document ID: US9435038B2 - Status: Granted - Kind: B2 - Application number: 14/473,424 - Filed: 2014-08-29 - Published: 2016-03-03 - Granted: 2016-09-06 - Earliest claimed: 2014-08-29 - Assignees: Varian Semiconductor Equipment Associates, Inc. - Applicants: Varian Semiconductor Equipment Associates, Inc. - Inventors: Thomas Omstead; William Davis Lee; Tristan Ma - Web page: https://patentgrep.com/patent/US9435038B2 ## CPC - C23F 17/00: Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 (coating for obtaining at least two superposed coatings either by methods not provided for in a single one of main groups C23C2/00 - C23C26/00, or by combinations of methods providedfor in subclasses C23C and C25D, C23C28/00) - C23F 1/00: Etching metallic material by chemical means (manufacture of printing surfaces B41C; manufacture of printed circuits H05K) - C23F 1/08: Apparatus, e.g. for photomechanical printing surfaces (photo- mechanical reproduction G03F) - C23G 1/02: with acid solutions - C23G 5/00: Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents - H01J 37/3171: {for ion implantation} - H10P 50/267: {using plasmas} - H10P 50/667: {by liquid etching only} - H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass - C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25 - C23G: CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract An improved method of etching a metal substrate is described. After a mask layer is applied to the metal substrate, an ion implantation process is performed which implants ions, such as oxygen ions, into the exposed regions of the metal substrate. This implantation creates regions of metal oxide, which may be more susceptible to etching. Afterwards, the exposed regions of metal oxide are subjected to an etching process. This process may be through vaporization or may be a wet etch process. In some embodiments, the etchant is selected so that the metal oxide binds with the etchant to form a volatile compound, which stays in the vapor or gaseous state. This may reduce the unwanted deposition of the metal to other surfaces. These ion implantation and etching processes may be repeated a plurality of times to create a recessed feature of the desired depth. ## Claims ### Claim 1 A method of forming a recessed feature in a metal substrate, comprising: implanting oxygen ions into a region of said metal substrate to form a metal oxide region having a thickness of about 10 nm; exposing said metal oxide region to an etchant; and repeating said implanting and exposing to create said recessed feature of a desired depth, wherein the oxygen ions are implanted at a plurality of energies so as to create a uniform distribution of oxygen ions throughout the metal oxide region. ### Claim 2 (depends on 1) The method of claim 1, wherein said etchant chemically reacts with metal oxide in said metal oxide region to form a volatile metal precursor. ### Claim 3 (depends on 2) The method of claim 2, wherein said etchant does not chemically react with said metal substrate. ### Claim 4 (depends on 3) The method of claim 3, wherein said etchant is in liquid form. ### Claim 5 (depends on 3) The method of claim 3, wherein said etchant comprises acetic acid. ### Claim 6 (depends on 2) The method of claim 2, wherein said etchant is introduced into a chamber and said method further comprises exhausting said volatile metal precursor from said chamber. ### Claim 7 (depends on 6) The method of claim 6, wherein the chamber is maintained at a pressure of less than 100 millitorr during the exposing. ### Claim 8 (depends on 1) The method of claim 1, wherein said etchant is in vapor or gas form. ### Claim 9 (depends on 1) The method of claim 1, wherein said etchant comprises HFAc. ### Claim 10 (depends on 1) The method of claim 1, further comprising applying a mask layer to said metal substrate prior to said implanting. ### Claim 11 (depends on 1) The method of claim 1, wherein said metal substrate comprises a transition metal. ### Claim 12 A method of forming a recessed feature in a metal substrate, comprising: performing a sputtering or etch process by directing hydrogen ions toward said substrate to create said recessed feature, wherein the sputtering or etch process creates metal depositions; implanting oxygen ions into the metal depositions created by said sputtering or etch process; and exposing said metal depositions to an etchant after said implanting. ### Claim 13 (depends on 12) The method of claim 12, wherein said etchant chemically reacts with metal oxide in said metal depositions to form a volatile metal precursor. ### Claim 14 (depends on 13) The method of claim 13, wherein said etchant comprises acetic acid. ### Claim 15 (depends on 12) The method of claim 12, wherein said etchant is in vapor or gas form. ### Claim 16 (depends on 12) The method of claim 12, wherein said etchant is in liquid form. ### Claim 17 (depends on 12) The method of claim 12, wherein said etchant comprises HFAc.