Composition for substrate materials and process for the same as well as a heat conductive substrate and process for the same

Abstract

A composition for substrate materials according to the present invention includes 70-95 wt. % of inorganic powder and 5-30 wt. % of thermosetting resin composition and is in a finely crushed condition. The composition for substrate materials is prepared, for example, by crushing into fine pieces and mixing the inorganic powder and the thermosetting resin composition. A heat conductive substrate is provided with an insulator body formed by heating and pressurizing said composition for substrate materials and a wiring pattern is provided in such a condition that it is exposed on the surface of the insulator body. A process for manufacturing the heat conductive substrate comprises forming said composition for substrate materials into the insulator body by casting the above mentioned composition for substrate materials into a metal mold to be heated and pressurized so that said thermosetting resin is cured.

What is claimed is:  
     
         1 . A composition for substrate materials including 70-95 wt. % of inorganic powder having electrical insulation and 5-30 wt. % of thermosetting resin composition and being in a finely crushed condition.  
     
     
         2 . A composition for substrate materials according to  claim 1 , wherein said composition is in a powder condition.  
     
     
         3 . A composition for substrate materials according to  claim 1 , wherein said composition is in a granulation condition.  
     
     
         4 . A composition for substrate materials according to  claim 2 , wherein said thermosetting resin composition is in a liquid condition at a room temperature and the entire composition including this thermosetting resin composition is in a powder condition.  
     
     
         5 . A composition for substrate materials according to  claim 3 , wherein said thermosetting resin composition is in a liquid condition at a room temperature and the entire composition including this thermosetting resin composition is in a granulation condition.  
     
     
         6 . A composition for substrate materials according to  claim 1 , wherein said inorganic powder is coated with said thermosetting resin composition.  
     
     
         7 . A composition for substrate materials according to  claim 6 , wherein said thermosetting composition is in a B-stage condition.  
     
     
         8 . A composition for substrate materials according to  claim 1 , wherein said inorganic powder is at least one kind chosen from among Al 2 O 3 , MgO, BN and AlN.  
     
     
         9 . A composition for substrate materials according to  claim 1 , wherein said inorganic powder has a grain diameter in a range of 0.1-100 μm.  
     
     
         10 . A composition for substrate materials according to  claim 1 , wherein said thermosetting resin composition includes as a main component at least one kind of thermosetting resin chosen from among epoxy resin, phenol resin and cyanate resin.  
     
     
         11 . A composition for substrate materials according to  claim 10 , wherein said thermosetting resin composition 
 includes brominated polyfunctional epoxy resin as a main component, and    further includes bisphenol A-type novolac resin as a curing agent and imidazol as a curing accelerator.    
     
     
         12 . A composition for substrate materials according to  claim 11 , wherein said imidazol is micro-encapsulated.  
     
     
         13 . A composition for substrate materials according to  claim 10 , wherein at least one kind chosen from among a coupling agent, a dispersing agent, a coloring agent and a mold-releasing agent is added to said thermosetting resin composition.  
     
     
         14 . A process for manufacturing a composition for substrate materials, wherein 70-95 wt. % of inorganic powder and 5-30 wt. % of thermosetting resin composition including thermosetting resin which is in a solid condition at a room temperature are crushed into fine pieces and mixed.  
     
     
         15 . A process for manufacturing a composition for substrate materials, comprising the steps of: 
 70-95 wt. % of inorganic powder and 5-30 wt. % of thermosetting resin composition including a thermosetting resin which is in a liquid condition at a room temperature are mixed; and    a mixture prepared at the foregoing step is granulated and crushed into fine pieces.    
     
     
         16 . A process for manufacturing a composition for substrate materials comprising the steps of: 
 70-95 wt. % of inorganic powder and 5-30 wt. % of thermosetting resin composition including a thermosetting resin which is in a liquid condition at a room temperature are mixed;    said thermosetting resin composition is turned into a B-stage by heat treating a mixture prepared at the foregoing step under a temperature condition lower than a curing temperature of said thermosetting resin; and    said mixture gained as the B-stage into which said thermosetting resin composition is turned is crushed into fine pieces.    
     
     
         17 . A process for manufacturing a composition for substrate materials comprising the steps of: 
 70-95 wt. % of inorganic powder and 5-30 wt. % of thermosetting resin composition including a thermosetting resin are mixed with a solvent in which said thermosetting resin is solved;    a mixture processed at the foregoing step is dried at a temperature lower than a curing temperature of said thermosetting resin to remove said solvent from said mixture; and    said mixture from which said solvent is removed is crushed into fine pieces.    
     
     
         18 . A process for manufacturing a composition for substrate materials according to  claim 17  wherein said solvent includes at least one kind chosen from among methyl ethyl ketone, isopropanol and toluene.  
     
     
         19 . A heat conductive substrate having an insulator body formed by heating and pressurizing a composition for substrate materials including 70-95 wt. % of inorganic powder having electric insulation and 5-30 wt. % of thermosetting resin composition and being in a finely crushed condition.  
     
     
         20 . A heat conductive substrate according to  claim 19 , wherein a wiring pattern is provided in such a condition that it is exposed on a surface of said insulator body.  
     
     
         21 . A heat conductive substrate according to  claim 20 , wherein said wiring pattern is a lead frame.  
     
     
         22 . A heat conductive substrate according to  claim 19 , wherein a metal plate for heat radiation is provided in such a condition that it is exposed on a surface of said insulator body.  
     
     
         23 . A process for manufacturing a heat conductive substrate comprising: 
 the first step that a composition for substrate materials including 70-95 wt. % of inorganic powder having electric insulation and 5-30 wt. % of thermosetting resin composition and being in a finely crushed condition is cast into a metal mold; and    the second step that said composition for substrate materials is formed into a insulator body by heating and pressurizing said composition for substrate materials within said metal mold so that said thermosetting resin is cured.    
     
     
         24 . A process for manufacturing a heat conductive substrate according to  claim 23 , wherein a pressure when said composition for substrate materials is heated and pressurized is in a range of 1-20 MPa.  
     
     
         25 . A process for manufacturing a heat conductive substrate according to  claim 23 , wherein a temperature when said composition for substrate materials is heated and pressurized is in a range of 140-260° C.  
     
     
         26 . A process for manufacturing a heat conductive substrate according to  claim 23 , wherein: 
 in said first step, a lead frame is arranged in advance within said metal mold, and then said composition for substrate materials is cast into said metal mold; and    in said second step, said insulator body and said lead frame are integrally molded by heating and pressurizing said composition for substrate materials.    
     
     
         27 . A process for manufacturing a heat conductive substrate according to  claim 26 , wherein: 
 in said first step, a metal plate for heat radiation is arranged within said metal mold into which said composition for substrate materials is cast; and    in said second step, said insulator body and said metal plate are integrally molded by heating and pressurizing said composition for substrate materials.    
     
     
         28 . A process for manufacturing a heat conductive substrate according to  claim 23 , wherein: 
 in said first step, a metal foil is arranged in advance within said metal mold, and then said composition for substrate materials is cast into within said metal mold; and    in said second step, said insulator body and said metal foil is integrally molded by heating and pressurizing said composition for substrate materials, and then said metal foil is pattern-processed into a wiring pattern.    
     
     
         29 . A process for manufacturing a heat conductive substrate according to  claim 28 , wherein said metal foil is copper foils having a thickness of 12-200 μm of which surface is roughened at least in a part facing the composition for substrate materials.  
     
     
         30 . A process for manufacturing a heat conductive substrate according to  claim 28 , wherein: 
 in said first step, a metal foil is arranged within said metal mold into which said composition for substrate materials is cast; and    in said second step, said insulator body and said metal foil are integrally molded by heating and pressurizing said composition for substrate materials, and then these metal foil is pattern-processed into a wiring pattern.