Abstract: Methods and systems for reducing stiction through roughening the surface and reducing the contact area in MEMS devices are disclosed. A method includes fabricating bumpstops on a surface of a MEMS device substrate to reduce stiction. Another method is directed to applying roughening etchant to a surface of a silicon substrate to enhance roughness after cavity etch and before removal of hardmask. Another embodiment described herein is directed to a method to reduce contact area between proof mass and UCAV (“upper cavity”) substrate surface with minimal impact on the cavity volume by introducing a shallow etch process step and maintaining high pressure in accelerometer cavity. Another method is described as to increasing the surface roughness of a UCAV substrate surface by depositing a rough layer (e.g. polysilicon) on the surface of the substrate and etching back the rough layer to transfer the roughness.

Abstract: A device includes a micro-electromechanical system (MEMS) device layer comprising a proof mass. The proof mass includes a first proof mass portion and a second proof mass portion. The first proof mass portion is configured to move in response to a stimuli. The second proof mass portion has a spring attached thereto. The device further includes a substrate disposed parallel to the MEMS device layer. The substrate comprises a bumpstop configured to limit motion of the first proof mass portion. The device includes a first electrode disposed on the substrate facing the second proof mass portion. The first electrode is configured to apply a pulling force onto the second proof mass portion and to move the second proof mass portion towards the first electrode.

Abstract: Provided herein is a method including forming a MEMS cap. A cavity is formed in the MEMS cap wafer, and a bond material is deposited on the MEMS cap wafer, wherein the bond material lines the cavity after the depositing. The MEMS cap wafer is bonded to a MEMS device wafer, wherein the bond material forms a bond between the MEMS cap wafer and the MEMS device wafer. A MEMS device is formed in the MEMS device wafer. The bond material is removed from the cavity.

Abstract: A method for DRIE matched release and/or the mitigation of photo resist pooling, comprising: depositing a first mask layer over a first surface of a silicon substrate; exposing a first portion and second portion of the first mask layer to a first etch process, wherein the exposing forms a first exposed layer; depositing a second mask layer over the first mask layer; exposing a third portion of the second mask layer to a second etch process, wherein the exposing forms a second exposed mask layer, and wherein the third portion overlaps the first portion of the first mask layer; developing the second mask layer and etching the third portion of the second mask layer and developing the first portion of the first mask layer; etching the first portion of the first mask layer to a first depth; and developing the first mask layer to reveal exposed portions of the first mask layer and etching the second portion of the silicon substrate to a second depth.

Abstract: A microelectromechanical (MEMS) system may comprise multiple sensors within cavities of the MEMS system. The operation of different sensors requires different pressures within the respective cavities. A first cavity may be sealed at a first pressure. A through-hole may be etched into a cap layer of the MEMS system to introduce gas into a second cavity such that the cavity has a desired pressure. The cavity may then be sealed by a MEMS valve to maintain the desired pressure in the second cavity.

Abstract: A device includes a micro-electromechanical system (MEMS) device layer comprising a proof mass. The proof mass includes a first proof mass portion and a second proof mass portion. The first proof mass portion is configured to move in response to a stimuli. The second proof mass portion has a spring attached thereto. The device further includes a substrate disposed parallel to the MEMS device layer. The substrate comprises a bumpstop configured to limit motion of the first proof mass portion. The device includes a first electrode disposed on the substrate facing the second proof mass portion. The first electrode is configured to apply a pulling force onto the second proof mass portion and to move the second proof mass portion towards the first electrode.

Abstract: A microelectromechanical (MEMS) system may comprise multiple sensors within cavities of the MEMS system. The operation of different sensors requires different pressures within the respective cavities. A first cavity may be sealed at a first pressure. A through-hole may be etched into a cap layer of the MEMS system to introduce gas into a second cavity such that the cavity has a desired pressure. The cavity may then be sealed by a MEMS valve to maintain the desired pressure in the second cavity.

Abstract: A method includes fusion bonding a first side of a MEMS wafer to a second side of a first handle wafer. A TSV is formed from a first side of the first handle wafer to the second side of the first handle wafer and into the first MEMS wafer. A dielectric layer is formed on the first side of the first handle wafer. A tungsten via is formed in the dielectric layer. Electrodes are formed on the dielectric layer. A second MEMS wafer is eutecticly bonded with a first eutectic bond to the electrodes, wherein the TSV electrically connects the first MEMS wafer to the second MEMS wafer. Standoffs are formed on a second side of the first MEMS wafer. A CMOS wafer is eutecticly bonded with a second eutectic bond to the standoffs, wherein the second eutectic bond includes different materials than the first eutectic bond.

Abstract: A method for DRIE matched release and/or the mitigation of photo resist pooling, comprising: depositing a first mask layer over a first surface of a silicon substrate; exposing a first portion and second portion of the first mask layer to a first etch process, wherein the exposing forms a first exposed layer; depositing a second mask layer over the first mask layer; exposing a third portion of the second mask layer to a second etch process, wherein the exposing forms a second exposed mask layer, and wherein the third portion overlaps the first portion of the first mask layer; developing the second mask layer and etching the third portion of the second mask layer and developing the first portion of the first mask layer; etching the first portion of the first mask layer to a first depth; and developing the first mask layer to reveal exposed portions of the first mask layer and etching the second portion of the silicon substrate to a second depth.

Abstract: Methods and systems for reducing stiction through roughening the surface and reducing the contact area in MEMS devices are disclosed. A method includes fabricating bumpstops on a surface of a MEMS device substrate to reduce stiction. Another method is directed to applying roughening etchant to a surface of a silicon substrate to enhance roughness after cavity etch and before removal of hardmask. Another embodiment described herein is directed to a method to reduce contact area between proof mass and UCAV (“upper cavity”) substrate surface with minimal impact on the cavity volume by introducing a shallow etch process step and maintaining high pressure in accelerometer cavity. Another method is described as to increasing the surface roughness of a UCAV substrate surface by depositing a rough layer (e.g. polysilicon) on the surface of the substrate and etching back the rough layer to transfer the roughness.

Abstract: Provided herein is a method including forming a MEMS cap. A cavity is formed in the MEMS cap wafer, and a bond material is deposited on the MEMS cap wafer, wherein the bond material lines the cavity after the depositing. The MEMS cap wafer is bonded to a MEMS device wafer, wherein the bond material forms a bond between the MEMS cap wafer and the MEMS device wafer. A MEMS device is formed in the MEMS device wafer. The bond material is removed from the cavity.

Abstract: A method includes fusion bonding a first side of a MEMS wafer to a second side of a first handle wafer. A TSV is formed from a first side of the first handle wafer to the second side of the first handle wafer and into the first MEMS wafer. A dielectric layer is formed on the first side of the first handle wafer. A tungsten via is formed in the dielectric layer. Electrodes are formed on the dielectric layer. A second MEMS wafer is eutecticly bonded with a first eutectic bond to the electrodes, wherein the TSV electrically connects the first MEMS wafer to the second MEMS wafer. Standoffs are formed on a second side of the first MEMS wafer. A CMOS wafer is eutecticly bonded with a second eutectic bond to the standoffs, wherein the second eutectic bond includes different materials than the first eutectic bond.