Patent - This invention is an adhesive film comprising a a top layer that is substantially UV curable and that has a glass transition temperature of 50degrees C. or less; and b a bottom layer that is substantially not UV-curable Additional embodiments include a bundled wafer lamination film, a semiconductor wafer with a multilayer adhesive film attached, a process for attaching a semiconductor die to a substrate, and a method of preventing individually diced dies from sticking to one another. This invention relates to multilayer adhesive films for use in semiconductor packages, processes for using those films, and semiconductor packages assembled with those films. The films of this invention, when used in bundled wafer backside lamination processes, do not cause individual dies to stick together after dicing. Adhesive films are often used in the fabrication of semiconductor packages, for example, in attaching silicon semiconductor dies to substrates. Generally, these films are compositions that are applied to a carrier and then B-staged to partially cure or dry the composition into a film form. The film may then be applied to a dicing tape, the carrier removed, and the exposed side of the film applied to the back side of a semiconductor wafer, thereby sandwiching the adhesive film between the back side of the wafer and the dicing tape. This enables the wafer to be diced into individual dies having adhesive film attached, the combination of die and film, including multilayer film, hereinafter called a die structure. The die structures are then picked off the dicing tape and placed on a substrate with the adhesive film adjacent to the substrate. The adhesive film, when cured, typically with the application of heat, bonds the die to the substrate. Due to operational considerations, it may necessary to have a time delay between dicing the wafer into individual dies and picking up the die for bonding to a substrate. In these cases it has been observed that the adhesive film on the back of individual dies sometimes sticks to the adhesive film on the back of adjacent dies, causing more than one die to be removed from the carrier or dicing tape. This is problematic and it would be preferable to have an adhesive film that will not cause dies to stick together after dicing and before die attach.
Source : APN 01-27-11 20110018127/US-A1 NDN- 041-1136-1032-7 INVENTOR- Lee, Byoungchul Cypress, CA, US PATENT APPLICATION NUMBER- 894816/12 DATE FILED- 2010-09-30 PUBLICATION NUMBER- 20110018127/US-A1 PUBLICATION DATE- 2011-01-27 MAILING ADDRESS- Henkel Corporation; 10 Finderne Avenue, Suite B; Bridgewater; NJ; 08807; US FIRM- Henkel Corporation US PATENT CLASS- 257729000O; X257678000; X438113000; X428343000; X4283550AC; X4283550EP; X257E21505; X257E23003; X257E23005 INTERNATIONAL PATENT CLASS- H01L02314; H01L02312; H01L02158; B32B02730; B32B02738; C09J00700
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