Electronic microcomponent of the variable capacitor or microswitch type, and process for fabricating such a component

Abstract

Process for fabricating electronic components, of the variable capacitor or microswitch type, comprising a fixed plate ( 1 ) and a deformable membrane ( 20 ) which are located opposite each other, which comprises the following steps, consisting in: depositing a first metal layer on an oxide layer ( 2 ), said first metal layer being intended to form the fixed plate; depositing a metal ribbon ( 10, 11 ) on at least part of the periphery and on each side of the fixed plate ( 1 ), said ribbon being intended to serve as a spacer between the fixed plate ( 1 ) and the deformable membrane ( 20 ); depositing a sacrificial resin layer ( 15 ) over at least the area of said fixed plate ( 1 ); generating, by lithography, a plurality of wells in the surface of said sacrificial resin layer; depositing, by electrolysis, inside the wells formed in the sacrificial resin ( 15 ), at least one metal region intended to form the deformable membrane ( 20 ), this metal region extending between sections of the metal ribbon ( 10, 11 ) which are located on each side of said fixed plate ( 1 ); removing the sacrificial resin layer ( 15 ).

1 . A process for fabricating electronic microcomponents, of the variable capacitor or microswitch type, comprising a fixed plate ( 1 ) and a deformable membrane ( 20 ) which are located opposite each other, which comprises the following steps, consisting in: 
 depositing a first metal layer on an oxide layer ( 2 ), said first metal layer being intended to form the fixed plate;    depositing a metal ribbon ( 10 ,  11 ) on at least part of the periphery and on each side of the fixed plate ( 1 ), said ribbon being intended to serve as a spacer between the fixed plate ( 1 ) and the deformable membrane ( 20 );    depositing a sacrificial resin layer ( 15 ) over at least the area of said fixed plate ( 1 );    generating, by lithography, a plurality of wells in the surface of said sacrificial resin layer;    depositing, by electrolysis, inside the wells formed in the sacrificial resin ( 15 ), at least one metal region intended to form the deformable membrane ( 20 ), this metal region extending between sections of the metal ribbon ( 10 ,  11 ) which are located on each side of said fixed plate ( 1 );    removing the sacrificial resin layer ( 15 ).    
     
     
         2 . The process as claimed in  claim 1 , wherein the oxide layer ( 2 ) is deposited on an integrated circuit.  
     
     
         3 . The process as claimed in  claim 1 , wherein the oxide layer ( 2 ) is made of quartz.  
     
     
         4 . The process as claimed in  claim 1 , wherein the first metal layer intended to form the fixed plate is inserted into a recess ( 3 ) formed in the oxide layer ( 2 ).  
     
     
         5 . The process as claimed in  claim 1 , wherein the first metal layer includes an extension ( 5 ) associated with a connection pad ( 6 ).  
     
     
         6 . The process as claimed in  claim 1 , wherein the ribbon ( 10 ,  11 ) is present along the periphery of the fixed plate ( 1 ), on two opposed sides of the latter.  
     
     
         7 . The process as claimed in  claim 1 , wherein the ribbon consists of a succession of individual segments.  
     
     
         8 . The process as claimed in  claim 1 , wherein the sacrificial resin layer ( 15 ) partly covers the peripheral ribbon ( 10 ,  11 ).  
     
     
         9 . The process as claimed in  claim 1 , which also includes a step consisting in etching the oxide layer in order to form one or more anchoring grooves ( 8 ,  9 ) intended to accommodate part of the peripheral ribbon ( 10 ,  11 ).  
     
     
         10 . The process according to  claim 1 , which also includes a step consisting in etching the oxide layer in order to form one or more anchoring grooves ( 8 ,  9 ) intended to accommodate part of the ends of the deformable membrane ( 20 ).  
     
     
         11 . The process as claimed in either of claims  9  and  10 , wherein the anchoring groove ( 8 ,  9 ) has a width (w) about twice the thickness of the deformable membrane ( 20 ).  
     
     
         12 . The process as claimed in  claim 11 , wherein the anchoring groove ( 8 ,  9 ) has a depth (d) more than one and a half times its width (w).  
     
     
         13 . The process as claimed in  claim 1 , which furthermore includes a step consisting, after the fixed plate has been deposited, in depositing a film ( 6 ) of a dielectric, intended to prevent the deformable membrane from bonding to said fixed plate.  
     
     
         14 . The process as claimed in  claim 1 , which furthermore includes a step consisting, after the sacrificial resin ( 15 ) has been removed, in producing, on the upper face of the deformable membrane or membranes, raised regions ( 25 ) capable of modifying the moment of inertia of the surface of the deformable membrane so as to produce membranes with programmed deformation.  
     
     
         15 . The process as claimed in  claim 14 , wherein the raised features are longitudinal ribs ( 25 ).  
     
     
         16 . The process as claimed in  claim 1 , wherein the metal used both for producing the fixed plate and the deformable membrane is chosen from the group comprising copper, chromium, nickel and alloys including these metals.  
     
     
         17 . A microcomponent of the variable capacitor or microswitch type, comprising: 
 a fixed metal plate ( 1 ) inserted into an oxide layer ( 2 );    at least two metal ribbons ( 10 ,  11 ) located peripherally and on each side of said fixed plate ( 1 );    at least one deformable metal membrane ( 20 ) located opposite said fixed plate ( 20 ) and resting at its two ends on the two metal ribbons.    
     
     
         18 . The microcomponent as claimed in  claim 17 , which is located on the upper face of an integrated circuit.  
     
     
         19 . The microcomponent as claimed in  claim 17 , wherein the deformable membrane ( 20 ) has, on its upper face, raised features ( 25 ) intended to modify its moment of inertia of the surface.  
     
     
         20 . The microcomponent as claimed in  claim 17 , wherein the fixed plate ( 1 ) is covered with a film ( 6 ) of a dielectric intended to prevent the deformable membrane ( 20 ) from bonding to the fixed plate ( 1 ).  
     
     
         21 . The microcomponent as claimed in  claim 17 , which includes anchoring grooves ( 8 ,  9 ) formed in the oxide layer ( 2 ) and located outside the fixed plate, said grooves ( 8 ,  9 ) being filled with a portion of the spacer ribbons ( 10 ,  11 ) and/or with the deformable membrane ( 20 ).  
     
     
         22 . The microcomponent as claimed in  claim 17 , wherein the metal constituting the fixed plate and the movable membrane is chosen from the group comprising copper, nickel and chromium.  
     
     
         23 . The microcomponent as claimed in  claim 17 , wherein the cross section of the deformable membrane ( 20 ) varies over the length of said deformable membrane.