US 11,920,012 B2
Release film and method of manufacturing release film
Keisuke Sakai, Matsudo (JP); Norifumi Iwawaki, Matsudo (JP); Nanae Tanaka, Matsudo (JP); Satoshi Hiramatsu, Matsudo (JP); and Akane Kawafuchi, Matsudo (JP)
Assigned to KOBAYASHI & CO., LTD., Tokyo (JP)
Appl. No. 17/251,109
Filed by KOBAYASHI & CO., LTD., Tokyo (JP)
PCT Filed Apr. 8, 2019, PCT No. PCT/JP2019/015353
§ 371(c)(1), (2) Date Dec. 10, 2020,
PCT Pub. No. WO2019/244448, PCT Pub. Date Dec. 26, 2019.
Claims priority of application No. 2018-119270 (JP), filed on Jun. 22, 2018.
Prior Publication US 2021/0253815 A1, Aug. 19, 2021
Int. Cl. C08J 7/04 (2020.01); B29C 33/68 (2006.01); B32B 27/36 (2006.01); H01L 21/56 (2006.01); H01L 23/29 (2006.01)
CPC C08J 7/042 (2013.01) [B29C 33/68 (2013.01); B32B 27/36 (2013.01); H01L 21/566 (2013.01); H01L 23/293 (2013.01); H01L 2924/181 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A release film for use in sealing a semiconductor with a resin comprising:
an oligomer bleeding prevention layer formed of an acrylic resin or a siloxane resin and laminated on a first face of a base layer that is formed of a polyethylene terephthalate resin;
a surface layer formed of a fluororesin and laminated on the oligomer bleeding prevention layer; and
a surface layer formed of a fluororesin and laminated on a second face of the base layer, or
an oligomer bleeding prevention layer formed of an acrylic resin or a siloxane resin and laminated on a second face of the base layer, and a surface layer formed of a fluororesin and laminated on the oligomer bleeding prevention layer that is laminated on the second face,
wherein the fluororesin that forms the surface layers is a cured product of a fluororesin composition containing a reactive functional group-containing fluoropolymer and a curing agent, the reactive functional group-containing fluoropolymer is a hydroxy group-containing tetrafluoroethylene polymer, and the curing agent is an isocyanate curing agent,
the fluororesin that forms the surface layer on at least one face of the base layer comprises particles having an average particle size of 1 μm to 10 μm determined by laser diffraction particle size analysis,
the content of the curing agent in the fluororesin composition is 15 parts by mass to 50 parts by mass relative to 100 parts by mass of the reactive functional group-containing fluoropolymer, and
the content of the particles in the fluororesin composition is 10 parts by mass to 30 parts by mass relative to 100 parts by mass of the reactive functional group-containing fluoropolymer.