Film-Assisted Molding (FAM) technologies.
Film-Assisted Molding is a cluster of proprietary technologies of Boschman Technologies comprising a variation on the transfer molding process. The Film-Assisted Molding process uses one or two plastic films in the mold. This film is sucked down into the inner surfaces of the mold (culls, runners and cavities) before the lead frames or substrates, i.e. the products to be encapsulated, are loaded into the mold. This is followed by the usual transfer molding process.
The molding material is first liquified by heat and pressure, and then forced into closed mold cavities and held there under additional heat and pressure until all material is solidified (i.e. cured). After opening the mold, the encapsulated products are unloaded. Next, the vacuum is removed and the film is transported across one length of the mold (renewed) and a new cycle can start. Film-Assisted Molding offers a number of advantages over conventional transfer molding. These include the easy release of the encapsulated products from the mold, and the fact that metal surfaces are kept clear of sticky molding compound. Another advantage is that the film functions as a soft cushion resulting in less wear of mold parts, i.e. a longer service life. Basically, there are 4 different process configurations within Film-Assisted Molding. There is Seal Film Technology (SFT) that uses a deformable seal film that is excellently suited for covering three-dimensional mold cavities, or the method that uses a non-deformable polyester-type adhesive film. This latter so-called Adhesive Film Technology (AFT) is meant to protect one flat side of the product from being encapsulated, e.g. metal contacts on flat surfaces. Boschman Technologies has further refined this technology so that different film can be used on either side of the product that will be encapsulated, with sealing film on top and adhesive or sealing film on the bottom. The method with seal film on both sides (SFT-SFT) is particularly suited for lead frame-mounted chips requiring package structuring on both sides. The method with seal film on one side and adhesive film on the other (AFT-SFT) is particularly suited for array packaging and leadless parts.
Film-Assisted Molding makes it possible to create open (windowed) packages by means of placing inserts in the bottom and/or top mold.