1. A photovoltaic assembly comprising:
a photovoltaic panel for converting light into electricity and comprising two opposite surfaces;
two curtains for absorbing solar heat to roast the photovoltaic panel when the two curtains are disposed to cover the two opposite surfaces of the photovoltaic panel, each of the two curtains comprising a stack of a reflective layer, a high thermal capacity layer and a transparent layer, wherein the high thermal capacity layer is sandwiched between the reflective layer and the transparent layer, the reflective layer being closer to the photovoltaic panel than the high thermal capacity layer and the transparent layer are when the two curtains cover the two opposite surfaces of the photovoltaic panel; and
two rollers each comprising a rotatable shaft for rolling each of the two curtains.
2. The photovoltaic assembly of claim 1, wherein the high thermal capacity layer comprises a black material.
3. The photovoltaic assembly of claim 1, further comprising a motor connected to the rotatable shaft for rolling each of the two curtains.
4. The photovoltaic assembly of claim 1, wherein the roller comprises a hollow cylinder-shaped housing to accommodate a rolled each of the two curtains.
5. The photovoltaic assembly of claim 1, wherein each of the two curtains has substantially the same area as either one of the two opposite surfaces of the photovoltaic panel.
6. The photovoltaic assembly of claim 1, wherein each of the two curtains is larger in area than either one of the two opposite surfaces of the photovoltaic panel.
7. The photovoltaic assembly of claim 1, wherein the two rollers are respectively disposed at two opposite edges of the photovoltaic panel.
8. The photovoltaic assembly of claim 1, wherein each of the two curtains comprises an insulation and moisture resistance material disposed at all edges of the stack of the reflective layer, the high thermal capacity layer and the transparent layer.
9. The photovoltaic assembly of claim 1, wherein the photovoltaic panel comprises an insulation and moisture resistance material disposed at all edges thereof.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for coupling a microelectronic device to a substrate comprising:
providing a substrate comprising a first surface, said first surface comprising a plurality of first metal bumps;
providing a microelectronic device comprising an active surface; such active surface comprising a plurality of second metal bumps; where at least one of the plurality of first metal bumps and the plurality of second metal bumps, comprises a solder;
disposing a polymer composition overlying the solder, where said polymer composition comprises a sacrificial polymer and a thermally activated base generator, said thermally activated base generator comprising a cation selected from formula 1, 2, or 3:
where each R1 is independently selected from hydrogen, a methyl or ethyl group, a linear, branched or cyclic C3-C12 alkyl group; a linear, branched or cyclic C3-C12 heteroalkyl group having from 1 to 4 heteroatoms independently selected from nitrogen, oxygen or sulfur; a C6-C10 aryl group; a C5-C10 heteroaryl group having from 1 to 4 heteroatoms independently selected from nitrogen, oxygen or sulfur; or where two R1 groups are taken together with any intervening atoms to form one or more cyclic alkyl or heteroalkyl groups as previously defined, and where for formula 1, at least one R1 is hydrogen;
providing the microelectronic device to the substrate such that each metal bump of the first plurality is aligned to a metal bump of the second plurality; where the polymer composition maintains such alignment;
heating the first plurality of metal bumps and the second plurality of bumps to a first temperature sufficient to melt the solder, such that the microelectronic device and the substrate become electrically and fixably coupled; the polymer composition providing a fluxing function; and
heating the polymer composition to a second temperature sufficient to cause thermal decomposition of the sacrificial polymer.
2. The method of claim 1, where the thermally activated base generator of the polymer composition disposed overlying the solder comprises a cation represented by formula 2 or formula 3.
3. The method of claim 1 or 2, where the thermally activated base generator of the polymer composition disposed overlying the solder further comprises a carboxylate anion.
4. The method of claim 3, where the thermally activated base generator of the polymer composition disposed overlying the solder comprises a cation represented by formula II.
5. The method of claim 1 where the sacrificial polymer of the polymer composition disposed overlying the solder is selected from a polypropylene carbonate, and a polycarbonate polymer comprising repeating units derived from one or more of endo-endo-2,3-norbornanedimethanol, exo-exo-2,3-norbornanedimethanol, endo-exo-2,3-norbornanedimethanol, exo-5-phenyl-exo-exo-2,3-norbornanedimethanol, exo-5-phenyl-endo-endo-2,3-norbornanedimethanol, norbornane spirocarbonate, and phenyl norbornane spirocarbonate.
6. The method of claim 5, where the thermally activated base generator of the polymer composition disposed overlying the solder comprises a cation represented by formula 2 or formula 3.
7. The method of claim 5 or 6, where the thermally activated base generator of the polymer composition disposed overlying the solder further comprises a carboxylate anion.
8. The method of claim 7, where the thermally activated base generator of the polymer composition disposed overlying the solder comprises a cation represented by formula 2.
9. The method of claim 1, where the first surface comprises a surface of a substrate and the active surface comprises a surface of a semiconductor chip and where the first metal bumps comprise a solder and the second metal bumps comprise copper.
10. The method of claim 9, where the thermally activated base generator comprises a cation represented by formula 2 and the sacrificial polymer is selected from a polypropylene carbonate, and a polycarbonate polymer comprising repeating units derived from one or more of endo-exo-2,3-norbornanedimethanol, endo-endo-2,3-norbornanedimethanol, exo-exo-2,3-norbornanedimethanol, exo-5-phenyl-exo-exo-2,3-norbornanedimethanol, exo-5-phenyl-endo-endo-2,3-norbornanedimethanol, norbornane spirocarbonate, and phenyl norbornane spirocarbonate.
11. The method of claim 9, where the thermally activated base generator is represented by formula IV and the sacrificial polymer is a polypropylene carbonate:
12. The method of claim 9, where the sacrificial polymer is selected from a polycarbonate polymer comprising repeating units derived from one or more of endo-endo-2,3-norbornanedimethanol, exo-exo-2,3-norbornanedimethanol, endo-exo-2,3-norbornanedimethanol, exo-5-phenyl-exo-exo-2,3-norbornanedimethanol, exo-5-phenyl-endo-endo-2,3-norbornanedimethanol, norbornane spirocarbonate, and phenyl norbornane spirocarbonate.
13. A sacrificial polymer composition comprising:
a polypropylene carbonate polymer having a weight average molecular weight of from 39,000 to 47,000 Dalton;
a thermally activated base generator selected from PT-393 or Et4N OAc.4H2O, or mixtures thereof; and
a solvent selected from to anisole or gamma butyrolactone.
14. The sacrificial polymer composition of claim 13 where the solvent is gamma butyrolactone.
15. The sacrificial polymer composition of claim 14 where the thermally activated base generator is PT-393.
16. The sacrificial polymer composition of claim 15 where the thermally activated base generator loading is from 0.5 parts per hundred polymer to 8 parts per hundred polymer, inclusive.
17. The sacrificial polymer composition of claim 15 further comprising 3 weight % of the composition Formic acid.