Liquid compression molding encapsulants
View Patent ↗Thermosetting resin compositions useful for liquid compression molding encapsulation of a silicon wafer are provided. The so-encapsulated silicon wafers offer improved resistance to warpage, compared to unencapsulated wafers or wafers encapsulated with known encapsulation materials.
1. A thermosetting resin composition, comprising
a thermosetting resin matrix comprising the combination of
an epoxy resin component, and
an epoxy curing agent consisting of a phenolic novolac component,
optionally an additional component selected from the group consisting of an episulfide resin, an oxazine, an oxazoline, a cyanate ester, a maleimide, a nadimide, an itaconimide, and combinations thereof;
a block copolymer,
a silica filler and
optionally a catalyst and accelerator,
wherein the block copolymer is an amphiphilic one selected from copolymers made from polystyrene, 1,4-polybutadiene and syndiotactic poly(methyl methacrylate); polymethylmethacrylate-block-polybutylacrylate-block polymethylmethacrylate copolymers; and combinations thereof,
wherein the silica filler comprises 50 to 90 percent by weight of the composition.
2. The composition of claim 1 , wherein when cured the composition exhibits a storage modulus in the range of about 20 GPas or less at room temperature, a CTE al of less than or equal to 10 ppm, and multiple Tgs.
3. The composition of claim 2 , wherein the multiple Tgs include a T g1 of about −70° C. to −30° C. and a T g2 of about 50° C. to 150° C.
4. The composition of claim 1 , wherein the block copolymer is present in an amount from 5 to 40 percent by weight.
5. The composition of claim 1 , wherein the silica filler comprises 70 to 90 percent by weight of the composition.
6. An encapsulated thinned silicon wafer comprising a thermosetting resin composition according to claim 1 disposed in contact with the thinned silicon wafer.
7. A method of improving warpage resistance in a thinned silicon wafer subjected to liquid compression molding comprising:
providing a thinned silicon wafer of a thickness of 25 μm to 300 μm;
molding a thermosetting resin composition according to claim 1 onto the silicon wafer to form an encapsulated wafer;
heat curing the encapsulated wafer to form a cured wafer; and
cooling the cured wafer to room temperature.
8. The method of claim 7 , wherein molding is at a temperature of 110° C. to 130° C., and heat curing is at a temperature from 110° C. to 150° C.
9. A liquid compression molding composition, comprising
a thermosetting resin matrix consisting of
an epoxy resin component made from bisphenol A, bisphenol F, bisphenol S, bisphenol E, biphenyl, and combinations thereof,
a phenolic novolac component,
optionally an epoxy reactive diluent,
optionally a cycloaliphatic epoxy, and
optionally an additional component selected from the group consisting of an episulfide resin, an oxazine, an oxazoline, a cyanate ester, a maleimide, a nadimide, an itaconimide, and combinations thereof;
a block copolymer,
a silica filler and
optionally a catalyst and accelerator,
wherein the block copolymer is an amphiphilic one selected from copolymers made from polystyrene, 1,4-polybutadiene and syndiotactic poly(methyl methacrylate); polymethylmethacrylate-block-polybutylacrylate-block polymethylmethacrylate copolymers; and combinations thereof,
wherein the silica filler comprises 50 to 90 percent by weight of the composition.