Interconnect arrangement and associated production methods

Abstract

An interconnect arrangement and fabrication method are described. The interconnect arrangement includes an electrically conductive mount substrate, a dielectric layer formed on the mount substrate, and an electrically conductive interconnect formed on the dielectric layer. At least a portion of the dielectric layer under the interconnect contains a cavity. To fabricate the interconnect arrangement, a sacrificial layer is formed on the mount substrate and the interconnect layer is formed on the sacrificial layer. The interconnect layer and the sacrificial layer are structured to produce a structured interconnect on the structured sacrificial layer. A porous dielectric layer is formed on a surface of the mount substrate and of the structured interconnect as well as the sacrificial layer. The sacrificial layer is then removed to form the cavity under the interconnect.

1 . An interconnect arrangement comprising: 
 an electrically conductive mount substrate;    a dielectric layer formed on the mount substrate; and    an electrically conductive interconnect formed on the dielectric layer,    wherein at least a portion of the dielectric layer under the interconnect contains a cavity.    
   
   
       2 . The interconnect arrangement of  claim 1 , further comprising a porous dielectric layer that adheres to the interconnect and bounds the cavity.  
   
   
       3 . The interconnect arrangement of  claim 1 , wherein the interconnect comprises a contact via that leads from the interconnect to a surface of the substrate and electrically connects to the substrate.  
   
   
       4 . The interconnect arrangement of  claim 1 , wherein the interconnect comprises a dummy contact via that leads from the interconnect to a surface of the substrate and does not electrically connect to the substrate.  
   
   
       5 . The interconnect arrangement of  claim 1 , wherein the interconnect comprises a barrier layer that prevents interconnect material from diffusing into the mount substrate.  
   
   
       6 . The interconnect arrangement of  claim 1 , further comprising a residual decomposition layer formed in the cavity on a surface of the mount substrate.  
   
   
       7 . An interconnect arrangement comprising: 
 an electrically conductive mount substrate;    a dielectric layer formed on the mount substrate;    an electrically conductive interconnect formed on the dielectric layer, at least a portion of the dielectric layer under the interconnect contains a cavity; and    dielectric supporting elements formed in the cavity on a surface of the mount substrate, the dielectric supporting elements support the interconnect.    
   
   
       8 . The interconnect arrangement of  claim 7 , further comprising a non-porous dielectric covering layer formed on the interconnect such that the cavity is also located to a side of the interconnect.  
   
   
       9 . The interconnect arrangement of  claim 7 , wherein the supporting elements are formed in a straight line and essentially at right angles to the interconnect.  
   
   
       10 . The interconnect arrangement of  claim 7 , wherein the supporting elements comprise islands.  
   
   
       11 . A method for production of an interconnect arrangement, the method comprising: 
 a) forming a sacrificial layer on an electrically conductive mount substrate;    b) forming an interconnect layer on the sacrificial layer;    c) structuring the interconnect layer and the sacrificial layer to produce a structured interconnect on the structured sacrificial layer;    d) forming a porous dielectric layer on a surface of the mount substrate and of the structured interconnect as well as the sacrificial layer; and    e) removing the sacrificial layer to form a cavity under the interconnect.    
   
   
       12 . The method of  claim 11 , wherein, in a), an opening for a contact via or a dummy contact via is formed in the sacrificial layer.  
   
   
       13 . The method of  claim 11 , wherein, in a) to c), a damascene or dual damascene process is carried out.  
   
   
       14 . The method of  claim 11 , wherein, in e) thermal conversion of the sacrificial layer is carried out in a temperature range from 300 to 600 degrees Celsius, with the gaseous decomposition products escaping through the porous layer.  
   
   
       15 . The method of  claim 11 , wherein, in e), a residual decomposition layer is formed on the surface of the mount substrate.  
   
   
       16 . A method for production of an interconnect arrangement, the method comprising: 
 a) forming a supporting structure on a mount substrate;    b) forming a sacrificial layer on a surface of the mount substrate and of the supporting structure;    c) planarizing the sacrificial layer to expose the surface of the supporting structure;    d) forming an interconnect layer on the surface of the sacrificial layer and of the supporting structure;    e) structuring the interconnect layer to produce a structured interconnect;    f) removing the sacrificial layer to form a cavity at least under the interconnect; and    g) forming a closed dielectric covering layer above the interconnect.    
   
   
       17 . The method of  claim 17 , wherein, after e), an opening for a contact via or a dummy contact via is formed in the sacrificial layer.  
   
   
       18 . The method of  claim 17 , wherein, in f), thermal conversion of the sacrificial layer is carried out in a temperature range from 300 to 600 degrees Celsius.  
   
   
       19 . The method of  claim 17 , wherein, in f), a residual decomposition layer is formed on the surface of the mount substrate.  
   
   
       20 . The method of  claim 17 , wherein, in a), the supporting structure is formed in a linear form or like islands.  
   
   
       21 . An interconnect arrangement comprising: 
 an electrically conductive mount substrate;    means for insulating the mount substrate, at least a portion of the means comprising a cavity; and    means for electrically interconnecting elements formed on the insulating means.    
   
   
       22 . The interconnect arrangement of  claim 21 , further comprising porous means for bounding the cavity.  
   
   
       23 . The interconnect arrangement of  claim 21 , wherein the interconnect means comprises barrier means for preventing interconnect material from diffusing into the mount substrate during fabrication.  
   
   
       24 . The interconnect arrangement of  claim 21 , further comprising residual decomposition means for permitting gaseous decomposition products created during fabrication to escape from the interconnect arrangement.  
   
   
       25 . The interconnect arrangement of  claim 21 , further comprising support means for supporting the interconnect means.