Semiconductor device with effective heat-radiation

Abstract

The semiconductor device has a silicon layer (SOI layer) ( 12 ) formed through a silicon oxide film ( 11 ) on a support substrate ( 10 ). A transistor (T 1 ) is formed in the SOI layer ( 12 ). The wiring ( 17 a ) is connected with a source of the transistor (T 1 ) through a contact plug ( 15 a ). A back metal ( 18 ) is formed on an under surface (back surface) of the support substrate ( 10 ) and said back metal ( 18 ) is connected with the wiring ( 17 a ) through a heat radiating plug ( 16 ). The contact plug ( 15 a ), the heat radiating plug ( 16 ) the wiring ( 17 a ) and the back metal ( 18 ) is made of a metal such as aluminum, tungsten and so on which has a higher thermal conductivity than that of the silicon oxide film ( 11 ) and the support substrate ( 10 ).

1 . A semiconductor device comprising: 
 a first insulating film;    a silicon layer formed on said first insulating film and in which a semiconductor element is built;    a second insulating film formed on said silicon layer;    a first wiring formed on said second insulating film;    a first plug connecting said semiconductor element of said silicon layer with said first wiring;    a cooling element formed under said first insulating film; and    a second plug connecting said first wiring with said cooling element, wherein    said first and second plugs and said first wiring have a higher thermal conductivity than that of said first insulating film, said second plug that is connected only with a source of said MOS transistor is connected with said cooling element.    
   
   
       2 . The semiconductor device according to  claim 1 , wherein 
 said cooling element is a Peltier cooling element.    
   
   
       3 . The semiconductor device according to  claim 2 , further comprising: 
 a support substrate composed of a material of higher resistance than that of said cooling element in a predetermined position between said first insulating film and said cooling element.    
   
   
       4 . The semiconductor device according to  claim 3 , wherein 
 a circuit region including at least one of a transistor, an inductor, a varactor and a resistance is provided in said semiconductor device, and    said predetermined position of said support substrate is below said circuit region.    
   
   
       5 . The semiconductor device according to  claim 1 , wherein 
 said first plug and said second plug are the same plug.    
   
   
       6 . A semiconductor device comprising: 
 a support substrate;    a first insulating film formed on said support substrate;    a silicon layer formed on said first insulating film and in which a semiconductor element is built;    a second insulating film formed on said silicon layer;    a first wiring formed on said second insulating film;    a first plug connecting said semiconductor element of said silicon layer with said first wiring; and    a second plug connecting said first wiring with said support substrate and reaching to the inside of said support substrate, wherein    said first and second plugs, said first wiring and said support substrate have a higher thermal conductivity than that of said first insulating film.    
   
   
       7 . The semiconductor device according to  claim 6 , wherein 
 said first plug and said second plug are the same plug.