# US 10,501,314 B2 · System and method for maintaining a smoothed and anti-stiction surface on a MEMS device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,314 B2 - Document ID: US10501314B2 - Status: Granted - Kind: B2 - Application number: 16/066,607 - Filed: 2016-12-29 - Published: 2019-01-17 - Granted: 2019-12-10 - Earliest claimed: 2015-12-30 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Jochen Stehle; Gary Yama - Web page: https://patentgrep.com/patent/US10501314B2 ## CPC - B81C 1/00333: {Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325} - B81B 3/0016: {Arrangements for avoiding sticking of the flexible or moving parts not provided for in groups B81B3/0005 - B81B3/0013} - B81C 2203/0118: Bonding a wafer on the substrate, i.e. where the cap consists of another wafer - B81C 2203/0136: Growing or depositing of a covering layer - B81C 2203/0145: Hermetically sealing an opening in the lid - B81C 2203/0154: Moulding a cap over the MEMS device - 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 method of fabricating a MEMS device includes an epi-polysilicon cap layer epitaxially growth on one of a substrate or a sacrificial layer deposited on the substrate. A portion of the epi-polysilicon cap layer has been removed to form a plurality of access openings. The sacrificial layer is etched away to form a cavity below the access openings. A barrier layer is deposited over the epi-polysilicon cap layer, inner walls of the cavity, and inner walls of the access openings using an atomic layer deposition (ALD) process. A refill epi-polysilicon layer is epitaxially grown in the access openings and seals the openings after the cavity is formed. ## Claims ### Claim 1 A Microelectromechanical system (MEMS) device comprising: a substrate; a sacrificial layer on the substrate; an etched structure formed in a portion of the sacrificial layer; a cap layer epitaxially grown on the sacrificial layer, the cap layer including: a first cap layer portion defining at least one access opening extending upwardly from the etched structure; and a second cap layer portion defining a lateral wall of the etched structure; a barrier layer including: a first barrier layer portion deposited on the first cap layer portion of the cap layer; a second barrier layer portion deposited on the second cap layer portion of the cap layer; and a refill material epitaxially grown on a portion of the first barrier portion and sealing the at least one access opening within the cap layer. ### Claim 2 (depends on 1) The MEMS device of claim 1 wherein the cap layer is a polysilicon layer. ### Claim 3 (depends on 1) The MEMS device of claim 1 wherein the barrier layer is an anti-stiction layer. ### Claim 4 (depends on 1) The MEMS device of claim 1 wherein the etched structure is formed by a vapor hydrofluoric (vHF) acid. ### Claim 5 (depends on 1) The MEMS device of claim 1 wherein the barrier layer is formed from Aluminum Oxide (Al2O3). ### Claim 6 (depends on 1) The MEMS device of claim 1, further comprising a second sacrificial layer deposited on the cap layer. ### Claim 7 (depends on 6) The MEMS device of claim 6, further comprising a second etched structure formed in a portion of the second sacrificial layer. ### Claim 8 A method of manufacturing a Microelectromechanical system (MEMS) device, comprising: providing a sacrificial layer on a substrate; epitaxially growing a cap layer over the sacrificial layer; forming at least one access opening through the cap layer; forming an etched structure in a portion of the sacrificial layer through the at least one access opening; depositing a first barrier layer portion on a first cap portion of the cap layer, the first cap portion defining the at least one access opening; depositing a second barrier layer portion on a second cap portion of the cap layer, the second cap portion defining a lateral wall of the etched structure; and epitaxially growing a refill material on a portion of the first barrier portion to seal the at least one access opening. ### Claim 9 (depends on 8) The method of claim 8 wherein the cap layer is a polysilicon layer. ### Claim 10 (depends on 8) The method of claim 8 wherein the barrier layer is an anti-stiction layer. ### Claim 11 (depends on 8) The method of claim 8 wherein the etched structure is formed by a vapor hydrofluoric (vHF) acid. ### Claim 12 (depends on 8) The method of claim 8 wherein the barrier layer is formed from Aluminum Oxide (Al2O3). ### Claim 13 (depends on 8) The method of claim 8, further comprising: providing a second sacrificial layer on the cap layer. ### Claim 14 (depends on 13) The method of claim 13, further comprising: forming a second etched structure in a portion of the second sacrificial layer. ### Claim 15 A Microelectromechanical system (MEMS) device, comprising: a substrate; a first layer on the substrate, the first layer including a lateral wall defining a gap region in the first layer; a second layer disposed over the first layer, the second layer including: a support structure disposed on the substrate in a portion of the gap region; and a cap portion supported by the support structure over the gap region so as to define a cavity between the cap portion and the substrate, the cap portion having at least one access opening that extends upwards from the cavity; a barrier material coated onto surfaces of the substrate that define the cavity, onto surfaces of the support structure that define the cavity, and onto surfaces of the cap portion that define the at least one access opening; and a refill material disposed on a portion of the barrier material coated onto the surfaces of the cap portion so as to seal closed the at least one access opening within the cap portion.