# US 8,541,854 B2 · Method of minimizing beam bending of MEMS device by reducing the interfacial bonding strength between sacrificial layer and MEMS structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,854 B2 - Document ID: US8541854B2 - Status: Granted - Kind: B2 - Application number: 13/349,596 - Filed: 2012-01-13 - Published: 2012-05-03 - Granted: 2013-09-24 - Earliest claimed: 2008-04-11 - Assignees: International Business Machines Corporation - Applicants: John M. Cotte; Nils D. Hoivik; Christopher Jahnes; Minhua Lu; Hongqing Zhang - Inventors: John M. Cotte; Nils D. Hoivik; Christopher Jahnes; Minhua Lu; Hongqing Zhang - Web page: https://patentgrep.com/patent/US8541854B2 ## CPC - B81C 1/00476: {removing a sacrificial layer (B81C1/00912 takes precedence)} - G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means} - Y10T 156/11: Methods of delaminating, per se; i.e. , separating at bonding face - Y10T 428/24942: including components having same physical characteristic in differing degree - Y10T 428/24975: No layer or component greater than 5 mils thick - Y10T 428/263: Coating layer not in excess of 5 mils thick or equivalent - 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) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The beam bending of a MEMS device is minimized by reducing interfacial strength between a sacrificial layer and a MEMS structure. ## Claims ### Claim 1 A structure for fabricating a MEMS device which comprises the structural layer of a MEMS device, a main sacrificial layer and an additional sacrificial buffer layer located between the MEMS structural layer and main sacrificial layer, wherein the additional sacrificial buffer layer is a different material than the main sacrificial layer and has weaker bonding strength to both the sacrificial layer and MEMS structural material as compared to the bonding strength between the main sacrificial layer and MEMS structural layer, wherein the main sacrificial layer has a thickness of about 10 nanometers to about 50,000 nanometers and the additional sacrificial buffer layer has a thickness of 100 nanometers or less and is thinner than the main sacrificial layer. ### Claim 2 (depends on 1) The structure according to claim 1, wherein the main sacrificial layer is selected from the group consisting of diamond like carbon, silicon, silicon dioxide, polyimide and photoresist. ### Claim 3 (depends on 2) The structure according to claim 2, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 60 MPa/ml1/2 or less. ### Claim 4 (depends on 2) The structure according to claim 2, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 20 MPa/ml1/2 or less. ### Claim 5 (depends on 2) The structure according to claim 2, wherein the sacrificial buffer layer is selected from the group consisting of photoresist, polyimide and diamond like carbon. ### Claim 6 (depends on 2) The structure according to claim 2, wherein the sacrificial buffer layer is diamond like carbon. ### Claim 7 (depends on 1) The structure according to claim 1, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 60 MPa/ml1/2 or less. ### Claim 8 (depends on 1) The structure according to claim 1, wherein the sacrificial buffer layer is selected from the group consisting of photoresist, polyimide and diamond like carbon. ### Claim 9 (depends on 1) The structure according to claim 1, wherein the main sacrificial layer is diamond like carbon. ### Claim 10 (depends on 1) The structure according to claim 1 wherein the MEMS structural layer comprises SiO2. ### Claim 11 (depends on 10) The structure according to claim 10 wherein the main sacrificial layer is silicon and the additional sacrificial buffer layer is diamond like carbon. ### Claim 12 A method for fabricating a MEMS device which comprises: obtaining a structure which comprises the structural layer of a MEMS device, a main sacrificial layer and an additional sacrificial buffer layer located between the MEMS structural layer and main sacrificial layer, wherein the additional sacrificial buffer layer is a different material than the main sacrificial layer and has weaker bonding strength to both the sacrificial layer and MEMS structural material as compared to the bonding strength between the main sacrificial layer and MEMS structural layer and separating the MEMS structural layer from the main sacrificial layer and additional sacrificial buffer layer to thereby provide the MEMS device, wherein the main sacrificial layer has a thickness of about 10 nanometers to about 50,000 nanometers and the additional sacrificial buffer layer has a thickness of 100 nanometers or less and is thinner than the main sacrificial layer. ### Claim 13 (depends on 12) The method according to claim 12, wherein the main sacrificial layer is selected from the group consisting of diamond like carbon, silicon, silicon dioxide, polyimide and photoresist. ### Claim 14 (depends on 12) The method according to claim 12, wherein the additional sacrificial buffer layer is selected from the group consisting of photoresist, polyimide or diamond like carbon. ### Claim 15 (depends on 12) The method according to claim 12, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 60 MPa/ml1/2 or less. ### Claim 16 (depends on 12) The method according to claim 12, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 20 MPa/ml1/2 or less. ### Claim 17 A method for fabricating a MEMS device which comprises: obtaining a structure which comprises the structural layer of a MEMS device, a main sacrificial layer and an additional sacrificial buffer layer located between the MEMS structural layer and main sacrificial layer, wherein the additional sacrificial buffer layer is a different material than the main sacrificial layer and has weaker bonding strength to both the sacrificial layer and MEMS structural material as compared to the bonding strength between the main sacrificial layer and MEMS structural layer and separating the MEMS structural layer from the main sacrificial layer and additional sacrificial buffer layer to thereby provide the MEMS device, wherein the additional sacrificial buffer layer has a bonding strength with the MEMS structural layer and main sacrificial layer of about 20 MPa/ml1/2 or less, and wherein the bond between the main sacrificial layer, additional sacrificial buffer layer and MEMS structural layer is broken or weakened prior to said separating the MEMS structural layer from the main sacrificial layer and additional sacrificial buffer layer. ### Claim 18 (depends on 17) The method according to claim 17, wherein the main sacrificial layer has a thickness of about 10 nanometers to about 50,000 nanometers and the additional sacrificial buffer layer has a thickness of 100 nanometers or less and is thinner than the main sacrificial layer. ### Claim 19 (depends on 17) The method according to claim 17, wherein the main sacrificial layer is selected from the group consisting of diamond like carbon, silicon, silicon dioxide, polyimide and photoresist. ### Claim 20 (depends on 17) The method according to claim 17, wherein the additional sacrificial buffer layer is selected from the group consisting of photoresist, polyimide or diamond like carbon.