# US 9,040,386 B2 · Method for varied topographic MEMS cap process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,386 B2 - Document ID: US9040386B2 - Status: Granted - Kind: B2 - Application number: 14/141,615 - Filed: 2013-12-27 - Published: 2015-01-29 - Granted: 2015-05-26 - Earliest claimed: 2013-07-23 - Assignees: Maxim Integrated Products, Inc. - Applicants: Maxim Integrated Products, Inc. - Inventors: Xuejun Ying; Li Li; Amit S. Kelkar; Brian S. Poarch - Web page: https://patentgrep.com/patent/US9040386B2 ## CPC - B81C 1/00626: {Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619} - B81B 7/0009: {Structural features, others than packages, for protecting a device against environmental influences (B81C1/00777 takes precedence)} - B81C 1/00269: {Bonding of solid lids or wafers to the substrate} - B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01) - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) ## Abstract A device includes sidewalls formed in a wafer surface, where the sidewalls descend to a recessed surface. The recessed surface generally promotes resist coverage on the wafer surface, including corners (e.g., junctions between the wafer surface and various surface topographies, such as cavities, the recessed surface, and so forth) on the wafer. In one or more implementations, a wet etching procedure is used to form the sidewalls and recessed surface. A resist material (e.g., a photoresist material) is deposited onto the wafer surface, where the photoresist fully covers one or more of the top corners of the wafer surface. In one or more implementations, the recessed surface is positioned adjacent a trench formed in the wafer to promote resist coverage on the top surface of the wafer. ## Claims ### Claim 1 A device comprising: a semiconductor wafer having a top surface and having a sidewall and a recessed surface formed in the top surface, the sidewall extending from the top surface to the recessed surface in the wafer; a trench formed in the semiconductor wafer, the trench positioned proximal to the recessed surface; and a photoresist material deposited onto the top surface of the semiconductor wafer, the photoresist material covering a top corner of the semiconductor wafer, the top corner comprising a junction between the top surface and the sidewall, the photoresist material extending from the top surface along the sidewall to the recessed surface, wherein the recessed surface preserves coverage of the top corner by supporting a portion of the photoresist material that extends along the sidewall to the top corner. ### Claim 2 (depends on 1) The device as recited in claim 1, further comprising a cavity formed in the top surface of the semiconductor wafer. ### Claim 3 (depends on 1) The device as recited in claim 1, further comprising one or more corners formed by the top surface of the semiconductor wafer proximal to the recessed surface. ### Claim 4 (depends on 1) The device as recited in claim 1, wherein the top surface is a bonding surface. ### Claim 5 (depends on 1) The device as recited in claim 1, wherein the semiconductor wafer is a microelectromechanical systems (MEMS) wafer. ### Claim 6 (depends on 5) The device as recited in claim 5, wherein the semiconductor wafer is a microelectromechanical systems cap (MEMS cap) wafer. ### Claim 7 (depends on 1) The device as recited in claim 1, wherein the sidewall has an angle of inclination from the recessed surface of from about 20 degrees to about 90 degrees. ### Claim 8 (depends on 1) The device as recited in claim 1, wherein the angle of inclination from the recessed surface of the sidewall is from about 54 degrees to about 55 degrees. ### Claim 9 (depends on 1) The device as recited in claim 1, further comprising a metal deposited on the top surface, where a top corner of the semiconductor wafer is free of the metal, the top corner comprising a junction between the top surface and the sidewall. ### Claim 10 (depends on 9) The device as recited in claim 9, wherein the metal is further located on the recessed surface, the metal on the recessed surface at least partially covered by a getter material. ### Claim 11 (depends on 10) The device as recited in claim 10, wherein a combined height of the metal and the getter material from the recessed surface is less than a height of the top surface from the recessed surface. ### Claim 12 A process comprising: providing a wafer; forming a trench in the wafer; forming a sidewall and a recessed surface in the wafer, the sidewall extending from a top surface of the wafer to the recessed surface in the wafer, the recessed surface proximal to the trench; and depositing a photoresist material onto the wafer and over a top corner of the semiconductor wafer, the top corner comprising a junction between the top surface and the sidewall, the deposited photoresist material extending from the top surface along the sidewall to the recessed surface, wherein the recessed surface preserves coverage of the top corner by supporting a portion of the photoresist material that extends along the sidewall to the top corner. ### Claim 13 (depends on 12) The process as recited in claim 12, further comprising: forming a cavity in a surface of the wafer. ### Claim 14 (depends on 12) The process as recited in claim 12, wherein forming the sidewall includes forming the sidewall with an angle of inclination from the recessed surface of from about 20 degrees to about 90 degrees. ### Claim 15 (depends on 14) The process as recited in claim 14, wherein the angle of inclination from the recessed surface of the sidewall is from about 54 degrees to about 55 degrees. ### Claim 16 (depends on 12) The process as recited in claim 12, further comprising: depositing a metal on the top surface, with a top corner of the semiconductor wafer being free of the deposited metal, the top corner comprising a junction between the top surface and the sidewall. ### Claim 17 (depends on 16) The process as recited in claim 16, further comprising: depositing the metal on the recessed surface; and at least partially covering the metal on the recessed surface with a getter material. ### Claim 18 A microelectromechanical (MEMS) device comprising: at least one of a processor or a sensor; and a device operably coupled to the at least one of the processor or the sensor, the device comprising: a semiconductor wafer having a top surface and having a sidewall and a recessed surface formed in the top surface, the sidewall extending from the top surface to the recessed surface in the wafer, the sidewall having an angle of inclination from the recessed surface of from about 20 degrees to about 90 degrees; a trench formed in the semiconductor wafer, the trench positioned proximal to recessed surface; and a metal deposited on the top surface of the semiconductor wafer, where a top corner of the semiconductor wafer is free of the metal, the top corner comprising a junction between the top surface and the sidewall.