Centrifugal method for filing high aspect ratio blind mirco vias powdered materials for circuit formation
View Patent ↗The present disclosure relates generally to semiconductor, integrated circuits, and particularly, but not by way of limitation, to centrifugal methods of filling high-aspect ratio vias and trenches with powders, pastes, suspensions of materials to act as any of a conducting, structural support, or protective member of an electronic component.
1. A process for filling via openings on a substrate comprising:
providing a substrate having via openings provided on a via-surface;
providing at least a layer of a particulate suspension on said via-surface;
centrifuging said substrate; and
brushing said via-surface during centrifugation.
2. The process for filling via openings, according to claim 1 , wherein said particulate suspension comprises:
a suspension fluid; and
a plurality of particles.
3. The process for filling via openings, according to claim 1 , wherein said centrifugation is performed with a tub rotor.
4. The process for filling via openings, according to claim 1 , wherein said centrifugation is performed with a swinging-bucket rotor.
5. The process for filling via openings, according to claim 1 , further comprising vibrating said substrate or particulate suspension during centrifugation.
6. The process for filling via openings, according to claim 1 , further comprising creating a vacuum in a centrifuge chamber.
7. The process for filling via openings, according to claim 1 , further comprising spraying said particulate suspension against said via-surface.
8. The process for filling via openings, according to claim 2 , wherein said suspension fluid is a non-reactive fluid.
9. The process for filling via openings, according to claim 8 , further comprising forming a substantially dry mass in said via.
10. The process for filling via openings, according to claim 8 , further comprising:
wetting said via with a via-wetting fluid; and
displacing a gas from said via with said via-wetting fluid.
11. The process for filling via openings, according to claim 10 , wherein said via-wetting fluid is said suspension fluid.
12. The process for filling via openings, according to claim 10 , wherein said via-wetting fluid has a high wetting capacity for said substrate.
13. The process for filling via openings, according to claim 10 , wherein said via-wetting fluid is miscible with said suspension fluid.
14. The process for filling via openings, according to claim 10 , wherein said via-wetting fluid is easily displaced by said suspension fluid.
15. The process for filling via openings, according to claim 10 , wherein said via-wetting occurs under a partial vacuum.
16. The process for filling via openings, according to claim 10 , wherein said via wetting occurs remote from said centrifuge.
17. The process for filling via openings, according to claim 10 , wherein said via wetting occurs in said centrifuge.
18. The process for filling via openings, according to claim 10 , wherein said via-wetting fluid has a low viscosity.
19. The process for filling via openings, according to claim 8 , wherein said nonreactive fluid comprises a fluid selected from the group consisting of water, organic solvents, and mixtures thereof.
20. The process for filling via openings, according to claim 19 , wherein said nonreactive fluid further comprises an auxiliary selected from the group consisting of dispersing agents, soaps, detergents, and surfactants.
21. The process for filling via openings, according to claim 2 , wherein said suspension fluid is a reactive fluid.
22. The process for filling via openings, according to claim 21 , further comprising curing said reactive fluid thereby forming a substantially solid mass in said via.
23. The process for filling via openings, according to claim 21 , wherein said reactive fluid comprises a curable liquid resin selected from the group consisting of epoxies, reactive crosslinkable polymers, cyanate esters, bismaleimides, phenol formaldehydes, polynorbornenes, polystyrenes, polyacrylates, polyesters, polyurethanes, polycarbonates, polyimides, polyaryletherketones, silicones, fluorinated resins, and derivatives thereof.
24. The process for filling via openings, according to claim 23 , wherein said reactive fluid further comprises a dispersing agent.
25. The process for filling via openings on a substrate, according to claim 24 , wherein said dispersing agent is selected from the group consisting of detergents, naphthalene sulfonic acid condensates, functionalized silanes, and hexamethylsilazane (HMDS).
26. The process for filling via openings, according to claim 2 , wherein said suspension fluid is a melt above a melting temperature.
27. The process for filling via openings, according to claim 26 , further comprising freezing said melt thereby forming a substantially solid mass in said via.
28. The process for filling via openings, according to claim 26 , wherein said melt comprises a molten material selected from the group consisting of molten solder alloys molten metals, molten thermoplastic polymers, and waxes.
29. The process for filling via openings, according to claim 2 , wherein said plurality of particles is selected from the group consisting of metals, alloys, cores coated with metals, and cores coated with alloys.
30. The process for filling via openings, according to claim 29 , wherein:
a first portion of said cores is coated with a first solder-forming metal; and
a second portion of said cores is coated with a solder-forming metal complementary to said first metal.
31. The process for filling via openings, according to claim 29 , wherein said core is selected from the group consisting of metal, glass, ceramic, crystalline powders, and polymers.
32. The process for filling via openings, according to claim 29 , wherein said core is a ceramic or an alloy having a negative volumetric coefficient of thermal expansion.
33. The process for filling via openings, according to claim 32 , wherein said ceramic or alloy is selected from the group consisting of zirconium tungstate (ZrW 2 O 8 ), beta-eucryptite, and nickel-titanium alloys.
34. The process for filling via openings, according to claim 32 , wherein said melt is a bismaleimide and said core filler or core particle is a ceramic, metal oxide, or other material having a negative coefficient of thermal expansion.
35. The process for filling via openings on a substrate, according to claim 1 , wherein said substrate is charged or electrically biased relative to said particulate suspension.
36. The process for filling via openings on a substrate, according to claim 1 , further comprising:
providing a brush means; and
wiping excess particles from said via-surface using said brush means.
37. The process for filling via openings on a substrate, according to claim 36 , wherein said brush means is selected from the group consisting of doctor blades and brushes having bristles larger than a via opening.
38. The process for filling via openings on a substrate, according to claim 1 , further comprising:
providing a filler-mask having through-via defined herein, said mask having a via-surface disposed to contact said fluid suspension and a substrate-contact surface disposed to contact said substrate via-surface; and
aligning said mask on said substrate via-surface.
39. The process for filling via openings on a substrate, according to claim 38 , wherein the openings of said through-via are wider at said mask via-surface than at said substrate-contact surface.
40. The process for filling via openings on a substrate, according to claim 39 , wherein said through-via has multiple substrate-contact surface openings.
41. The process for filling via openings on a substrate, according to claim 38 , further comprising:
providing a substrate having an array of via openings, wherein said array comprises a plurality of sub-arrays;
providing a first filler-mask having a first subset of through-vias disposed to align with a first sub-array of vias from among the plurality of sub-arrays;
providing a first fluid suspension having a first composition;
filling said first sub-array of vias with said first suspension;
providing at least a second filler-mask having at least a second subset of through-vias disposed to align with a second sub-array of vias from among the plurality of sub-arrays;
providing at least a second fluid suspension having a second composition; and
filling said second sub-array of vias with said second fluid suspension.
42. The process for filling via openings on a substrate, according to claim 38 , further comprising:
providing an array of through-vias having openings on a bottom surface of said substrate; and
providing a gas-permeable film over said via openings on said bottom surface.
43. The process for filling via openings on a substrate, according to claim 1 , further comprising removing an excess of fluid or particles from said substrate via-surface.
44. The process for filling via openings on a substrate, according to claim 43 , wherein said removing comprises a technique selected from doctor-blading and chemical mechanical polishing.
45. The process for filling via openings on a substrate, according to claim 1 , wherein said particulate suspension comprises a thermoplastic composite sheet.
46. The process for filling via openings on a substrate, according to claim 45 , further comprising:
placing said thermoplastic composite sheet on said via-surface; and
heating said sheet thereby forming a melt.