Low refractive index resin composition for TPP nano 3D printing and photonic wire bonding method using the same
Disclosed are a low refractive index resin composition for TPP nano 3D printing and photonic wire bonding method using the same. The low refractive index resin composition for TPP nano 3D printing is made of a fluorinated resin composition with a low refractive index including a (meth)acrylic reactive group with sufficient solvency for a photoinitiator for TPP reaction. As a result, by supporting to print a micro-sized single-mode optical waveguide as well as cladding of an optical waveguide surrounding the single-mode optical waveguide thus formed through a TPP nano 3D printing method, a photonic wire bonding (PWB) method that can manufacture a photonic integrated circuit (PIC) with minimal optical loss and high reliability is proposed.
1 . A low refractive index resin composition for two photon polymerization (TPP) nano 3D printing, comprising:
30 to 70 wt % of perfluoro ether oligomer;
8 to 30 wt % of fluorinated monomer;
10 to 40 wt % of fluorinated (meth)acrylate oligomer; and
0.5 to 2.0 wt % of photoinitiator for TPP reaction.
2 . The low refractive index resin composition of claim 1 , wherein the perfluoro ether oligomer has a structure of [Formula 1] below
Where,
R 1 is each independently a (meth)acrylate group having a hydrocarbon (CH 2 ) number of 2 to 10,
R 2 is each independently —CH 2 O— or —CH 2 (OCH 2 CH 2 ) a O— (a is an integer from 1 to 3),
R 3 is an aromatic or aliphatic hydrocarbon group having 6 to 20 carbon atoms,
R 4 is each independently —CH 2 —, —CH 2 CH 2 — or —CH 2 (OCH 2 CH 2 ) a — (a is an integer from 1 to 10),
m, o, p, q, and r are repeating numbers for each repeating unit,
m and o are 1 to 6,
r is 1 to 5,000,
p is 1 to 20, and
a ratio p/q of p to q ranges from 0.8 to 2.5.
3 . The low refractive index resin composition of claim 1 , wherein the fluorinated monomer has a fluorine content of 30 to 60 wt %.
4 . The low refractive index resin composition of claim 3 , wherein the fluorinated monomer is selected from the group consisting of 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, 1H,1H,5H-octafluoropentyl acrylate, 1H,1H,5H-octafluoropentyl methacrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 1H,1H,2H,2H-nonafluorohexyl acrylate, 1H,1H,2H,2H-nonafluorohexyl methacrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, 1H,1H,2H,2H-tridecafluoro-n-octyl acrylate, H,1H,2H,2H-tridecafluoro-n-octyl methacrylate, and 1,6-bis(acryloyloxy)-2,2,3,3,4,4,5,5-octafluorohexane.
5 . The low refractive index resin composition of claim 1 , wherein the photoinitiator for the TPP reaction is selected from the group consisting of a bis-triazole-based initiator, a benzylamine-based initiator, an aminostyryl-triazines-based initiator, an imidazole-based initiator, a benzyl morpholino phenyl-based initiator, a bengal-based initiator, an erythrosine-based initiator, an isopropylthioxan-based initiator, a thienyl coumarin-based initiator, and a diphenyl phosphine-based initiator.
6 . The low refractive index resin composition of claim 1 , wherein the fluorinated (meth)acrylate oligomer has a structure of [Formula 5] below
Where,
k, l, m, and n are constants, each having a value between 0 and 10,000,
R is —H, —CH 3 , or a hydrocarbon group having 20 or less carbon atoms,
R f is a fluorocarbon group having 2 to 40 carbon atoms including fluorocarbons (—CF 2 —, —CF 3 ),
F 1 is a hydrocarbon group having 2 to 40 carbon atoms and containing at least one (meth)acrylate, vinyl or epoxy reactive group,
F 2 is a silane containing 1 to 3 methoxy reactive groups (—OCH 3 ) or ethoxy reactive groups (—OCH 2 CH 3 ), and
F 3 is a hydrocarbon group that does not react with a urethane bonding reaction and has 2 to 40 carbon atoms, and is a hydrocarbon group in which a part of the bonded hydrogen (H) is substituted with oxygen (O) or nitrogen (N).
7 . The low refractive index resin composition of claim 6 ,
wherein a molar ratio of k, l, m, and n is adjusted in a range of 60 to 80% for k, 2 to 20% for l, 2 to 10% for m, and 2 to 20% for n, respectively.
8 . A low refractive index resin composition for two photon polymerization (TPP) nano 3D printing, comprising:
30 to 70 wt % of fluorinated siloxane oligomer having a structure of [Formula 2] below;
8 to 30 wt % of fluorinated monomer;
10 to 40 wt % of fluorinated (meth)acrylate oligomer; and
0.5 to 2.0 wt % of photoinitiator for TPP reaction
Where,
R 1 is each independently a (meth)acrylate group having a hydrocarbon (CH 2 ) number of 2 to 10,
R 2 is a hydrogenated carbon group or a fluorinated carbon group having 2 to 20 carbon atoms,
R 3 is an alkoxysilane group having 1 to 5 silicon atoms
l, m, n, and o are repeating numbers for each repeating unit, all ranging from 1 to 5,000.