| 摘要 |
<p>The specification describes and claims a method of making a cavity package which comprises procuring a package body (10) having a cavity within which an operative element (e.g. a silicon chip (20)) is located and having a securing surface to which a lid (16) may be secured, and applying onto the operative element in the cavity a deposit of a silicone gel-forming composition to cover the operative element with a layer of desired thickness of silicone gel (26). The silicone gel-forming composition may comprise an intimate mixture of (i) an organopolysiloxane having a viscosity from 100 to 10,000 mm<2>/s at 25 DEG C which is a copolymer of units of the general formulae RViSiO, R2SiO and CH3R2SiO0.5 where each R represents a methyl or phenyl group and Vi represents a vinyl group; (ii) a liquid hydrogen- siloxane of the general formula HRCH3SiO(R2SiO)nSiCH3RH where each R represents a methyl or a phenyl group and n has an average value such that the hydrogensiloxane has a viscosity of not more than about 10,000 mm<2>/s and (iii) a platinum catalyst, the R groups of (i) and (ii) being at least predominantly methyl groups. Prior to application of the silicone gel-forming composition to cover the operative element, a coating of a surface-active composition comprising a fluorine compound is formed on surfaces of the cavity at that end of the cavity which is adjacent the securing surface of the package body which extend heightwise of the operative element when the deposit of silicone gel is applied thereto.</p> |
