Compositions for electronic circuitry applications and methods relating thereto
Compositions useful in circuitry substrates are described which have a polyimide component, and a sterically hindered hydrophobic epoxy component. Generally, a flowable precursor is applied and then cured to a wholly or partially solidified mass. The invention is also directed to methods of forming a passive electrical component upon or into a circuit board.
1 . An electronic substrate comprising:
a. a polyimide component having a glass transition temperature greater than 250° C., and
b. a sterically hindered hydrophobic epoxy component, wherein the weight ratio of polyimide component (“A”) to epoxy component (“B”) is A:B, where A is between and including 1 to 15 and where B is 1, and
wherein the substrate is a semiconductor device stress buffer layer, an interconnect dielectric layer, a circuitry protective overcoat layer, a bond pad redistribution layer, or a solder bump under fill.
2 . An electronic substrate in accordance with claim 1 , wherein:
a. the polyimide component comprises a phenolic moiety; and
b. the sterically hindered hydrophobic epoxy component is represented by the following formula:
where
z is an alkyl, alkoxy, phenyl, phenoxy, halogen, or a combination thereof;
Y is oxygen; sulfur; methylene; fluorenylidene; ethylidene; sulfonyl; cyclohexylidene; 1-phenylethylidene; C(CH 3 ) 2 ; C(CF 3 ) 2 ; or a combination thereof; and
m is an integer between, and including, 0 and 5; and
wherein the paste further comprises a blocked or unblocked tertiary aromatic amine catalysts.
3 . An electronic substrate in accordance with claim 2 further comprising an electrically conductive material, wherein the electrically conductive material is a carbon, a metal, or a metal oxide, and wherein the epoxy component is tetramethyl biphenol epoxy (TMBP), tetramethylbisphenol A (TMBPA), tetrabromobisphenol-A, or a combination thereof.
4 . An electronic substrate in accordance with claim 3 , further comprising a thermal cross-linking agent.
5 . An electronic substrate in accordance with claim 4 , wherein the paste is solidified and bonded directly to copper.
6 . An electronic substrate in accordance with claim 1 , wherein the polyimide component is represented by the general formula:
where X is SO 2 , C(CF 3 ) 2 , C(CF 3 ) 2 C(CF 3 )phenyl, C(CF 3 )CF 2 CF 3 , C(CF 2 CF 3 )phenyl or a combination thereof,
and where Y is derived from a diamine component, wherein from 2 to 50 mole percent of the diamine component is a phenolic-containing diamine.
7 . An electronic substrate in accordance with claim 6 , wherein the phenol containing diamine is selected from a group consisting of: 2,2′-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (6F-AP); 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB); 2,4-diaminophenol, 2,3-diaminophenol; 3,3′-diamino-4,4′-dihydroxy-biphenyl; 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; and combinations thereof.
8 . An electronic substrate in accordance with claim 1 , wherein the polyimide is derived from one or more of the following dianhydrides: 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA), 2,2-bis(3,4-dicarboxyphenyl)1,1,1,3,3,3-hexafluoropropane dianhydride (6-FDA), 1-phenyl-1,1-bis(3,4-dicarboxyphenyl)-2,2,2-trifluoroethane dianhydride, 1,1,1,3,3,4,4,4-octylfluoro-2,2-bis(3,4-dicarboxyphenyl)butane dianhydride, 1-phenyl-2,2,3,3,3-pentafluoro-1,1-bis(3,4-dicarboxylphenyl)propane dianhydride, 4,4′-oxydiphthalic anhydride (ODPA), 2,2′-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2′-bis(3,4-dicarboxyphenyl)-2-phenylethane dianhydride, 2,3,6,7-tetracarboxy-9-trifluoromethyl-9-phenylxanthene dianhydride (3FCDA), 2,3,6,7-tetracarboxy-9,9-bis(trifluoromethyl)xanthene dianhydride (6FCDA), 2,3,6,7-tetracarboxy-9-methyl-9-trifluoromethylxanthene dianhydride (MTXDA), 2,3,6,7-tetracarboxy-9-phenyl-9-methylxanthene dianhydride (MPXDA), 2,3,6,7-tetracarboxy-9,9-dimethylxanthene dianhydride (NMXDA) and combinations thereof.
9 . An electronic substrate in accordance with claim 2 , wherein the electrically conductive material is a reduced oxide of a metal selected from the group consisting of Ru, Bi, Gd, Mo, Nb, Cr and Ti.
10 . An electronic substrate in accordance with claim 2 , wherein the electrically conductive material is a metal carbide, a metal nitride, a metal boride, a titanium nitride, a carbide, a zirconium boride, a tungsten boride or a combination thereof.
11 . An electronic substrate in accordance with claim 1 , wherein the polyimide component is crosslinked.
12 . An electronic substrate in accordance with claim 1 , wherein the polyimide component and epoxy component are crosslinked together by means of a sterically hindered phenol crosslinking agent, wherein the amount of sterically hindered phenol added to the polyimide component and the epoxy component is between 0.6 and 3.0 mole percent of the amount of sterically hindered epoxy component.
13 . An electronic substrate in accordance with claim 12 , wherein the sterically hindered phenol is a member of a group consisting of: 3,3′,5,5′-tetramethylbiphenol-4,4′-diol, 4,4′-isopropylidenebis(2,6-dimethylphenol), 4,4′-isopropylidenebis(2,6-dibromophenol) and combinations thereof.
14 . An electronic substrate in accordance with claim 12 , wherein the phenol is represented by the general formula:
where Z is an alkyl, alkoxy, phenyl, phenoxy, halogen or combinations thereof,
where Y is a covalent bond, oxygen, sulfur, methylene, fluorenylidene, ethylidene, sulfonyl, cyclohexylidene, 1-phenylethylidene, C(CH 3 ) 2 , or C(CF 3 ) 2 , and
where m is an integer between and including 0, 1, 2, 3, 4 and 5.
15 . An electronic substrate in accordance with claim 1 further comprising a crosslinking agent selected from a group consisting of blocked isocyanates, polyhydroxystyrene, epichlorohydrin, phenol formaldehyde, and 1,1,1-tris(p-hydroxyphenyl)ethane triglycidyl ether and reaction products thereof.
16 . An electronic substrate in accordance with claim 1 further comprising a filler component from a group consisting of barium titanate, barium strontium titanate, lead magnesium niobate, titanium oxide, talc, fumed silica, silica, fumed aluminum oxide, aluminum oxide, bentonite, calcium carbonate, iron oxide, titanium dioxide, mica, glass, barium nitride, aluminum nitride, aluminum oxide coated aluminum nitride, silicon carbide, boron nitride, aluminum oxide, graphite, beryllium oxide, silver, copper, diamond and combinations thereof.
17 . An electronic substrate in accordance with claim 1 further comprising a metal adhesion agent selected from a group consisting of polyhydroxyphenylether, polybenzimidazole, polyetherimide, polyamideimide, 2-amino-5-mercaptothiophene, 5-amino-1,3,4-thiodiazole-2-thiol, benzotriazole, 5-chloro-benzotriazole, 1-chloro-benzotriazole, 1-carboxy-benzotriazole, 1-hydroxy-benzotriazole, 2-mercaptobenzoxazole, 1H-1,2,4-triazole-3-thiol, mercaptobenzimidazole and reaction products thereof.
18 . An electronic substrate in accordance with claim 1 , wherein the substrate comprises a polymer thick film (PTF) resistor, polymer thick film (PTF) electrical conductor, a discrete capacitor, or a planar capacitor.
19 . A method of forming a passive electrical component for a circuit board, comprising:
(a) preparing a composition comprising a polyimide component, a sterically hindered hydrophobic epoxy and an organic solvent;
(b) applying this composition to an electrically conductive foil;
(c) heating the printed foil so as to bond the composition to the foil, to remove the screen printing solvent, and to cure the formulation to form a solid mass;
(d) laminating the foil with the cured composition component side down to an organic circuit board so as to attach the composition to the organic circuit board; and
(e) etching the foil to form at least one of two terminations that contact the composition to yield a passive electrical component.