Microelectromechanical device having a common ground plane and method for making aspects thereof

Abstract

The present invention relates to MEM switches. More specifically, the present invention relates to a system and method for making MEM switches having a common ground plane. One method for making MEM switches includes: patterning a common ground plane layer on a substrate; forming a dielectric layer on the common ground plane layer; depositing a DC electrode region through the dielectric layer to contact the common ground plane layer; and depositing a conducting layer on the DC electrode region so that regions of the conducting layer contact the DC electrode region, so that the common ground plane layer provides a common ground for the regions of the conducting layer

1 . A method for forming a common ground for an microelectromechanical device comprising acts of:
 patterning a common ground plane layer on a substrate comprising acts of:
 depositing a ground plane photoresist pattern to form a common ground plane layer on at least a portion of a substrate having a substrate area; 
 depositing the common ground plane layer into the ground plane photoresist pattern; and 
 removing the ground plane photoresist pattern; 
   forming a dielectric layer on the common ground plane layer comprising acts of:
 depositing a dielectric layer having a thickness and an area on the common ground plane layer; 
 depositing a DC via photoresist pattern on the dielectric layer, patterned to leave a DC electrode via exposed; 
 etching through the thickness of a portion of the area of the dielectric layer at the DC electrode via to form a DC via in the dielectric layer, where the DC via connects with the common ground plane layer; and 
 removing the DC via photoresist pattern; 
   depositing a DC electrode region through the dielectric layer to contact the common ground plane layer; and   depositing a conducting layer on the DC electrode region so that regions of the conducting layer contact the DC electrode region, so that the common ground plane layer provides a common ground for the regions of the conducting layer comprising acts of:
 depositing a DC electrode region photoresist pattern; 
 depositing a conducting layer on the DC electrode region photoresist pattern and dielectric layer to form a set of DC electrodes in the set of DC electrode regions, where a DC electrode is in contact with the common ground plane layer through the DC via; and 
 removing the DC electrode region photoresist pattern; 
   depositing a sacrificial layer on the dielectric layer and the conducting layer, the sacrificial layer having a thickness; and   etching a plurality of tooth regions into the sacrificial layer proximate a portion of the conducting layer, such that the tooth regions, in a final device, provide a reduced adhesion area when the device closes.   
   
   
       2 . A method for forming a common ground for an microelectromechanical device as set forth in  claim 1 , further comprising acts of:
 depositing an anchor site photoresist pattern to provide for an anchor site;   etching through the sacrificial layer to an electrode region in order to expose a portion of the conducting layer at a DC electrode region to form an anchor site;   removing the anchor site photoresist pattern;   depositing an insulating first structure layer on the sacrificial layer and the anchor site, the insulating first structure layer having an area;   depositing a top electrode photoresist pattern for etching through the anchor site for providing contact to the conducting layer and for forming a top electrode space;   etching through the insulating first structure layer across at least a portion of the anchor site so that a portion of the conducting layer is exposed, and etching through the insulating first structure layer and through a portion of the thickness of the sacrificial layer at a top electrode site so that a top electrode space is defined through the insulating first structure layer, and into the sacrificial layer, proximate an electrode region;   removing the top electrode photoresist pattern;   depositing a device separation photoresist pattern on the insulating first structure layer, the device separation photoresist pattern forming separation regions for electrically separating desired areas of the microelectromechanical device and for separating desired devices;   depositing a conducting second structure layer on the insulating first structure layer, the exposed portion of the conducting layer, and in the top electrode space, the conducting second structure layer having an area;   removing the device separation photoresist pattern to eliminate unwanted portions of the conducting second structure layer in order to electrically separate desired areas of the microelectromechanical device and for separating desired devices;   depositing an insulating third structure layer on the microelectromechanical device, across the substrate area, the insulating third structure layer having an area; and   depositing a device shape photoresist pattern on the microelectromechanical device, across the substrate area, with the device shape photoresist pattern defining desired device shapes by selective exposure; and   selectively etching through exposed portions of the insulating first structure layer and the insulating third structure layer to isolate an microelectromechanical device having a desired shape; and   removing the device shape photoresist pattern.   
   
   
       3 . A method for forming a common ground for an microelectromechanical device comprising acts of:
 patterning a common ground plane layer on a substrate;   forming a dielectric layer on the common ground plane layer;   depositing a DC electrode region through the dielectric layer to contact the common ground plane layer;   depositing a conducting layer on the DC electrode region so that regions of the conducting layer contact the DC electrode region, so that the common ground plane layer provides a common ground for the regions of the conducting layer;   depositing a sacrificial layer, the sacrificial layer having a thickness; and   etching a plurality of tooth regions into the sacrificial layer proximate a portion of the conducting layer, such that the tooth regions, in a final device, provide a reduced adhesion area when the device closes.   
   
   
       4 . A method for forming a common ground for an microelectromechanical device comprising acts of:
 patterning a common ground plane layer on a substrate;   forming a dielectric layer on the common ground plane layer;   depositing a DC electrode region through the dielectric layer to contact the common ground plane layer;   depositing a conducting layer on the DC electrode region so that regions of the conducting layer contact the DC electrode region, so that the common ground plane layer provides a common ground for the regions of the conducting layer;   depositing an anchor site photoresist pattern to provide for an anchor site;   etching through the sacrificial layer to an electrode region in order to expose a portion of the conducting layer at a DC electrode region to form an anchor site;   removing the anchor site photoresist pattern;   depositing an insulating first structure layer on the sacrificial layer and the anchor site, the insulating first structure layer having an area;   depositing a top electrode photoresist pattern for etching through the anchor site for providing contact to the conducting layer and for forming a top electrode space;   etching through the insulating first structure layer across at least a portion of the anchor site so that a portion of the conducting layer is exposed, and etching through the insulating first structure layer and through a portion of the thickness of the sacrificial layer at a top electrode site so that a top electrode space is defined through the insulating first structure layer, and into the sacrificial layer, proximate an electrode region;   removing the top electrode photoresist pattern;   depositing a device separation photoresist pattern on the insulating first structure layer, the device separation photoresist pattern forming separation regions for electrically separating desired areas of the microelectromechanical device and for separating desired devices;   depositing a conducting second structure layer on the insulating first structure layer, the exposed portion of the conducting layer, and in the top electrode space, the conducting second structure layer having an area;   removing the device separation photoresist pattern to eliminate unwanted portions of the conducting second structure layer in order to electrically separate desired areas of the microelectromechanical device and for separating desired devices;   depositing an insulating third structure layer on the microelectromechanical device, across the substrate area, the insulating third structure layer having an area;   depositing a device shape photoresist pattern on the microelectromechanical device, across the substrate area, with the device shape photoresist pattern defining desired device shapes by selective exposure;   selectively etching through exposed portions of the insulating first structure layer and the insulating third structure layer to isolate an microelectromechanical device having a desired shape; and   removing the device shape photoresist pattern.   
   
   
       5 . A method of forming tooth regions on a metal portion of an microelectromechanical device comprising acts of:
 etching a plurality of tooth regions into a sacrificial layer proximate a portion of a conducting layer; and   depositing a dielectric layer over the sacrificial layer such that portions of the dielectric layer conform with the tooth regions to form teeth; whereby the dielectric layer may be urged into contact with another portion of the microelectromechanical device with the teeth providing a reduced adhesion area.   
   
   
       6 . A method of forming tooth regions on a metal portion of an microelectromechanical device as set forth in  claim 5 , further comprising acts of:
 patterning a conducting layer on a substrate such that portions of the conducting layer form electrodes; and   depositing a sacrificial layer on portions of the substrate and the conducting layer, where the sacrificial layer deposited is the sacrificial layer into which tooth regions are etched, wherein the tooth regions are formed protruding from a region selected from a group consisting of the substrate and the electrodes.   
   
   
       7 . A method of forming tooth regions on a metal portion of an microelectromechanical device as set forth in  claim 6 , further comprising acts of:
 depositing an anchor site photoresist pattern to provide for an anchor site;   etching through the sacrificial layer to an electrode region in order to expose a portion of the conducting layer at a DC electrode region to form an anchor site;   removing the anchor site photoresist pattern;   depositing an insulating first structure layer on the sacrificial layer and the anchor site, the insulating first structure layer having an area;   depositing a top electrode photoresist pattern for etching through the anchor site for providing contact to the conducting layer and for forming a top electrode space;   etching through the insulating first structure layer across at least a portion of the anchor site so that a portion of the conducting layer is exposed, and etching through the insulating first structure layer and through a portion of the thickness of the sacrificial layer at a top electrode site so that a top electrode space is defined through the insulating first structure layer, and into the sacrificial layer, proximate an electrode region;   removing the top electrode photoresist pattern;   depositing a device separation photoresist pattern on the insulating first structure layer, the device separation photoresist pattern forming separation regions for electrically separating desired areas of the microelectromechanical device and for separating desired devices;   depositing a conducting second structure layer on the insulating first structure layer, the exposed portion of the conducting layer, and in the top electrode space, the conducting second structure layer having an area;   removing the device separation photoresist pattern to eliminate unwanted portions of the conducting second structure layer in order to electrically separate desired areas of the microelectromechanical device and for separating desired devices;   depositing an insulating third structure layer on the microelectromechanical device, across the substrate area, the insulating third structure layer having an area; and   depositing a device shape photoresist pattern on the microelectromechanical device, across the substrate area, with the device shape photoresist pattern defining desired device shapes by selective exposure; and   selectively etching through exposed portions of the insulating first structure layer and the insulating third structure layer to isolate an microelectromechanical device having a desired shape; and   removing the device shape photoresist pattern.   
   
   
       8 . A common ground for an microelectromechanical device comprising:
 a substrate layer;   a common ground plane layer formed on a portion of the substrate layer;   a dielectric layer formed on the common ground plane layer and the substrate layer, the dielectric layer formed with conductor spaces therein, where at least one of the conductor spaces is in contact with the ground metal layer, the dielectric layer further including a dielectric top surface; and   a conducting layer formed as a set of conductors in the conductor spaces of the dielectric layer, with at least one of the conductors in contact with the common ground plane layer, the conducting layer having a conducting layer top surface, and where the dielectric top surface and the conducting layer top surface are formed in a substantially co-planar fashion to provide a planarized substrate structure.