LASER-SEEDING FOR ELECTRO-CONDUCTIVE PLATING
A workpiece ( 100 ) having substrate, such as a glass substrate, can be etched by a laser or by other means to create recessed features ( 200, 202 ). A laser-induced forward transfer (LIFT) process or metal oxide printing process can be employed to impart a seed material ( 402 ), such as a metal, onto the glass substrate, especially into the recessed features ( 200, 202 ). The seeded recessed features can be plated, if desired, by conventional techniques, such as electroless plating, to provide conductive features ( 500 ) with predictable and better electrical properties. The workpieces ( 100 ) can be connected in a stacked such that subsequently stacked workpieces ( 100 ) can be modified in place.
1 . A method of transferring a portion of a donor film, formed of a metal and supported by a transparent donor substrate, from the donor substrate, the method comprising:
directing a beam of laser energy through the donor substrate to impinge at a first location of the donor film, wherein characteristics of the beam of laser energy are sufficient to generate a melt front within a first region of the donor film, said melt front extending from an interface between the donor substrate and the donor film to a side of the donor film opposite the interface; and
after generating said melt front within the first region of the donor film, directing the beam of laser energy through the donor substrate to impinge on at a second location of the donor film, wherein characteristics of the beam of laser energy are sufficient to extend the melt front from the first region of the donor film to a second region of the donor film.
2 . The method of claim 1 , wherein the donor film has a thickness greater than 1 μm.
3 . The method of claim 2 , wherein the donor film has a thickness greater than 10 μm.
4 . The method of claim 3 , wherein the donor film has a thickness less than 250 μm.
5 . The method of claim 1 , wherein the beam of laser energy has an average power greater than 100 W.
6 . The method of claim 1 , wherein the beam of laser energy is manifested as a series of laser pulses.
7 . The method of claim 6 , wherein a pulse repetition rate of the series of laser pulses is at least 10 MHz.
8 . The method of claim 7 , wherein a pulse repetition rate of the series of laser pulses is at least 100 MHz.
9 . A method of forming a feature directly on a surface of a workpiece by transferring a portion of a donor film supported by a transparent donor substrate onto a workpiece, wherein the donor film has a thickness and the donor substrate is positioned in proximity to a workpiece with the donor film facing toward the workpiece, the method comprising:
directing a beam of laser energy through the donor substrate to impinge at a first location of the donor film, wherein characteristics of the beam of laser energy are sufficient to melt a first region of the donor film and expel the melted first region of the donor film onto the surface of the workpiece such that a height of the feature on the workpiece is greater than the thickness of the donor film.
10 . The method of claim 9 , wherein the donor film has a thickness greater than 1 μm.
11 . The method of claim 10 , wherein the donor film has a thickness greater than 10 μm.
12 . The method of claim 11 , wherein the donor film has a thickness less than 250 μm.
13 . The method of claim 9 , wherein the beam of laser energy has an average power greater than 100 W.
14 . The method of claim 9 , wherein the beam of laser energy is manifested as a series of laser pulses.
15 . The method of claim 14 , wherein a pulse repetition rate of the series of laser pulses is at least 10 MHz.
16 . The method of claim 15 , wherein a pulse repetition rate of the series of laser pulses is at least 100 MHz.
17 . The method of claim 1 , further comprising, after forming the feature, extending a height of the feature by directing a beam of laser energy through the donor substrate to impinge at a second location of the donor film, wherein characteristics of the beam of laser energy are sufficient to melt a second region of the donor film and expel the melted second region of the donor film onto the feature.