Method of making release coatings for composite materials

Abstract

A release film for soft composite materials is provided. The release film contains a film with a closely packed self-assembled monolayer. A method of applying soft composite materials to a substrate without loss of the soft composite material to the release film is also provided. The method is useful in applications such as applying thermal pastes to semiconductor packaging.

1 . A method of fabricating a release film for a soft composite material comprising applying a monolayer of closely packed self-assembled molecules to at least one side of a film. 
   
   
       2 . The method as claimed in  claim 1 , wherein the monolayer of closely packed self-assembled molecules comprises an aliphatic group. 
   
   
       3 . The method as claimed in  claim 2 , wherein the aliphatic group is a C10 to C30 aliphatic group. 
   
   
       4 . The method as claimed in  claim 1 , wherein the closely packed self-assembled molecules are at least one selected from the group consisting of alkylphosphonates, alkyl phosphates, alkyl carboxylic acids, alkyl silanes, halogenated silanes, alkyl thiols, alkanethiolates and alkyl disulfides. 
   
   
       5 . The method as claimed in  claim 1 , wherein the film is a metal film, a metal film with a metal oxide coating, a metallized polymer film, a metallized polymer film with a metal oxide coating, a polymer film or a semiconductor film. 
   
   
       6 . The method as claimed in  claim 1 , wherein the film is a polymer film coated with aluminum, gold, titanium, copper or silver and wherein the polymer film is selected from the group consisting of polyester, polypropylene, polyethylene, polycarbonate, polyethylene naphthalate, polyvinyl chloride and fluoropolymer film. 
   
   
       7 . The method as claimed in  claim 1 , wherein the film is an aluminum film, a silver film, a titanium film, a gold film, or a copper film. 
   
   
       8 . The method as claimed in  claim 1 , wherein the film is an aluminized Mylar® film. 
   
   
       9 . The method as claimed in  claim 1 , wherein the film comprises a metal oxide coating. 
   
   
       10 . The method as claimed in  claim 9 , wherein the metal oxide coating is alumina or titania. 
   
   
       11 . The method as claimed in  claim 10 , wherein the film comprising a metal oxide coating is a polymer film or a metal film. 
   
   
       12 . The method as claimed in  claim 1 , wherein the film is about 1 mil to about 5 mils in thickness. 
   
   
       13 . The method as claimed in  claim 1 , wherein the release film has a water contact angle of about 100 degrees or greater. 
   
   
       14 . The method as claimed in  claim 1 , wherein the monolayer of closely packed self-assembled molecules are applied by dissolving the molecules in a solvent to form a solution, exposing the solution to the film, then rinsing the exposed film with solvent followed by drying. 
   
   
       15 . The method as claimed in  claim 1 , wherein the monolayer of closely packed self-assembled molecules is at least one selected from the group consisting of decylphosphonic acid and dodecylphosphonic acid. 
   
   
       16 . A release film produced by the method as claimed in  claim 1 . 
   
   
       17 . A method for producing a preform comprising applying a soft composite material to the release film as claimed in  claim 16 , wherein the monolayer of closely packed self-assembled molecules are between the film and the soft composite material. 
   
   
       18 . A preform produced by the method as claimed in  claim 17 . 
   
   
       19 . The preform as claimed in  claim 18 , wherein the soft composite material is a thermal paste. 
   
   
       20 . A method for introducing a thermal paste into a semiconductor package comprising aligning the preform as claimed in  claim 19  with at least one chip wherein the thermal paste faces the backside of the chip, mounting the preform onto the backside of the chip, applying sufficient pressure to the mounted preform to ensure adhesion of the thermal paste to the backside of the chip, peeling the release film of the preform from the thermal paste leaving the thermal paste on the backside of the chip, optionally mounting other components to the semiconductor package and compressing the thermal paste to a thickness with sufficient pressure. 
   
   
       21 . A semiconductor package produced by the method as claimed in  claim 20 .