THERMAL LASER EVAPORATION SYSTEM AND METHOD OF PROVIDING A THERMAL LASER BEAM AT A SOURCE

Abstract

The present invention is related to a thermal laser evaporation system (10), the thermal laser evaporation system (10) comprising: a laser light source (30) for providing a thermal laser beam (34) for evaporating one or more materials (22) from a source (20); a thermal laser beam shaping system (40) comprising a collimation lens (42) and a focusing lens (44) for directing the thermal laser beam (34) onto the source (20); a vacuum chamber (12); a vacuum window (14) for conducting the thermal laser beam (34) into the vacuum chamber (12); and an aperture (16) arranged within the vacuum chamber (12) between the vacuum window (14) and the source (20).

Further, the present invention is related to a method of providing a thermal laser beam (34) at a source (20) in order to evaporate one or more materials (22) from the source (20); the method comprising the steps of: providing a thermal laser beam (34); directing the thermal laser beam (34) via a thermal laser beam shaping system (40) comprising a collimation lens (42), a shaping device (60) and a focusing lens (44) into a vacuum chamber (12) comprising a vacuum window (12) for conducting the thermal laser beam (34) into the vacuum chamber (12) and through an aperture (16) arranged within the vacuum chamber (12) at the source (20).

Claims

1-24. (canceled)

25. A thermal laser evaporation system, the thermal laser evaporation system comprising: a laser light source for providing a thermal laser beam for evaporating one or more materials from a source; a thermal laser beam shaping system comprising a collimation lens and a focusing lens for directing the thermal laser beam onto the source; a vacuum chamber; a vacuum window for conducting the thermal laser beam into the vacuum chamber; and an aperture arranged within the vacuum chamber between the vacuum window and the source, wherein the thermal laser beam shaping system comprises a shaping device arranged in between the collimation lens and the focusing lens for adapting at least one of a position, a shape, and a size of the thermal laser beam at the source.

26. The thermal laser evaporation system according to claim 25, wherein the shaping device preserves a parallel or at least essentially parallel alignment of the thermal laser beam after the collimation lens.

27. The thermal laser evaporation system according to claim 25, wherein the collimation lens and the focusing lens are stationary within the laser beam shaping system.

28. The thermal laser evaporation system according to claim 25, wherein the shaping device comprises at least some of the following components selected from the group of members consisting of one or more mirrors, one or more beam compressors, one or more beam expanders, one or more beam splitters, one or more lenses, one or more prisms and combinations of the foregoing.

29. The thermal laser evaporation system according to claim 25, wherein the shaping device comprises one of the following shape adapting elements for adapting the shape of the thermal laser beam: Anamorphic prism pairs Combination of cylindrical lenses Beam clipping elements Free-form mirrors.

30. The thermal laser evaporation system according to claim 25, wherein the shaping device comprises one of the following size adapting elements for adapting the size of the thermal laser beam: A defocusing lens and a matched focusing lens A focusing lens and a matched defocusing lens Beam clipping elements Beam compressors Beam expanders Free-form mirrors.

31. The thermal laser evaporation system according to claim 25, wherein the shaping device comprises one of the following position adapting elements for adapting the position of the thermal laser beam on the source: Prisms Mirrors, in particular free-form mirrors Diffractive optical elements Beam clipping elements.

32. The thermal laser evaporation system according to claim 31, wherein the thermal laser beam shaping system comprises a driving apparatus for moving at least one of the position adapting elements for scanning the source by adapting the position of the thermal laser beam on the source.

33. The thermal laser evaporation system according to claim 25, wherein the thermal laser beam shaping system further comprises a splitting device for splitting the thermal laser beam coming from the laser light source into two or more partial laser beams, wherein the shaping device is configured to adapt at least one of a position, a shape, and a size of the two or more partial laser beams.

34. The thermal laser evaporation system according to claim 32, wherein the splitting device comprises one of the following splitting elements for splitting the thermal laser beam coming from the laser light source into two or more partial laser beams: Mirrors Prisms Apertures.

35. The thermal laser evaporation system according to claim 33, wherein the shaping device is configured to adapt the two or more partial laser beams differently with respect to at least one of a position, a shape, and a size of the two or more partial laser beams.

36. The thermal laser evaporation system according to claim 25, wherein the thermal laser beam is impinging onto the source at an angle between 30° and 60° so that an elliptical beam spot adjusted by the laser beam shaping system directed at the source produces a circular beam spot on the source.

37. The thermal laser evaporation system according to claim 25, wherein the collimation lens and/or the focusing lens is integrated into the shaping device.

38. The thermal laser evaporation system according to claim 25, wherein the focusing lens focuses the thermal laser beam on a pointlike focal volume located in the vacuum chamber between the vacuum window and the source, and wherein the aperture comprises an aperture opening and is arranged with its aperture opening at the focal volume for shielding the vacuum window from particles evaporated from the source.

39. A method of providing a thermal laser beam at a source in order to evaporate one or more materials from the source; the method comprising the steps of: providing a thermal laser beam; directing the thermal laser beam via a thermal laser beam shaping system comprising a collimation lens, a shaping device and a focusing lens into a vacuum chamber comprising a vacuum window for conducting the thermal laser beam into the vacuum chamber and through an aperture arranged within the vacuum chamber at the source, wherein the step of directing the thermal laser beam via the thermal laser beam shaping system comprises a configuration of at least one of a position, a shape, and a size of the thermal laser beam at the source by the shaping device.

40. The method according to claim 39, whereby the method is carried out by a thermal laser evaporation system, the thermal laser evaporation system comprising: a laser light source for providing the thermal laser beam for evaporating one or more materials from the source; the thermal laser beam shaping system comprising a collimation lens and a focusing lens for directing the thermal laser beam onto the source; the vacuum chamber; the vacuum window for conducting the thermal laser beam into the vacuum chamber; and the aperture arranged within the vacuum chamber between the vacuum window and the source, wherein the thermal laser beam shaping system comprises a shaping device arranged in between the collimation lens and the focusing lens for adapting at least one of a position, a shape, and a size of the thermal laser beam at the source.

41. The method according to claim 39, whereby a parallel or at least essential parallel alignment of the thermal laser beam after the collimation lens is preserved by the shaping device.

42. The method according to claim 39, whereby the shape of the thermal laser beam is adapted by clipping parts of the thermal laser beam and/or by using anamorphic prism pairs and/or a combination of cylindrical lenses and/or free-form mirrors for altering the shape of the thermal laser beam.

43. The method according to claim 42, whereby a thermal laser beam provided by the laser light source with circular cross section is transformed by the shaping device into a thermal laser beam with an elliptical cross section.

44. The method according to claim 39, whereby the size of the thermal laser beam is adapted by clipping parts of the thermal laser beam and/or by using a matched pair of a defocusing lens and a focusing lens and/or beam compressors and/or beam expanders and/or free-form mirrors.

45. The method according to claim 39, whereby the position of the thermal laser beam on the source is adapted by clipping parts of the thermal laser beam and/or by using position adapting elements, in particular mirrors and/or prisms and/or diffractive optical elements, for altering the position of the thermal laser beam within the beam shaping system.

46. The method according to claim 45, whereby adapting the position of the thermal laser beam includes scanning the laser beam across the source by moving at least one of the position adapting elements by a driving apparatus of the thermal laser beam shaping system.

47. The method according to claim 39, whereby the step of directing the thermal laser beam via the thermal laser beam shaping system comprises splitting the thermal laser beam coming from the laser light source into two or more partial laser beams by a splitting device of the thermal laser beam shaping system.

48. The method according to claim 39, wherein the thermal laser beam shaping system focuses the thermal laser beam on a pointlike focal volume located in the vacuum chamber between the vacuum window and the source, and wherein an aperture is arranged with its aperture opening at the focal volume and shields the vacuum window from particles evaporated from the source.

Description

[0090] The present invention is further described hereinafter with reference to illustrated embodiments shown in the accompanying drawings. There is shown:

[0091] FIG. 1 A thermal laser evaporation system according to the invention with a thermal laser beam shaping system altering a size of the laser beam,

[0092] FIG. 2 A thermal laser evaporation system according to the invention with a thermal laser beam shaping system altering a position of the laser beam,

[0093] FIG. 3 A thermal laser evaporation system according to the invention with a thermal laser beam shaping system altering a size and a shape of the laser beam, and

[0094] FIG. 4 A thermal laser evaporation system according to the invention with a thermal laser beam shaping system splitting the laser beam in two partial laser beams.

[0095] All FIGS. 1 to 4 show different embodiments of a thermal laser evaporation system 10 according to the invention. Accordingly, in the following the common parts of the laser evaporation systems 10 depicted in FIGS. 1 to 4 are described together, whereby the differences of the embodiments are pointed out.

[0096] The depicted thermal laser evaporation systems 10 comprise a laser light source 30, whereby in all embodiments the terminal end of an optical fiber 32 is shown. The laser beam 34 is directed by a laser beam shaping system 40 onto a source 20 placed within a vacuum chamber 12.

[0097] The source 20 provides the material 22 to be evaporated and/or sublimated by the impinging laser beam 34. The laser beam 34 enters the vacuum chamber 12 through a vacuum window 14.

[0098] The laser beam shaping system 40 focus the laser beam 34 onto a pointlike focal volume located within the vacuum chamber 12 between the vacuum window 14 and the source 20. At and around this focal volume, an aperture 16 is arranged, whereby an aperture opening 18 of the aperture is aligned with respect to the pointlike focal volume of the laser beam 34. The aperture provides shielding the vacuum window 14 from a deposition of evaporated and/or sublimated material 22 of the source 20.

[0099] The depicted embodiments of the laser evaporation system 10 essentially differ in their laser beam shaping systems 40. Hence, in the following, these laser beam shaping systems 40 and their functionalities are described.

[0100] All depicted laser beam shaping systems 40 share a collimation lens 42 at an upstream end 52 of the laser beam shaping system 40 and a focusing lens 44 at the respective downstream end 54 of the laser beam shaping system 40. In this connection it should be noted that the upstream end 52 is located closest to the laser light source 30 and the downstream end 54 is located furthest away from the laser light source 30.

[0101] At least an additional shaping device 60 (see FIGS. 1 to 3) or an additional splitting device 46 (see FIG. 4) is arranged in between the collimation lens 42 and the focusing lens 44. The laser beam 34 emerging from the optical fiber 32 is divergent in most of the cases. The collimation lens 42 is adapted to this convergence and transfers the incoming laser beam 34 into a parallel aligned laser beam 34. The focusing lens 44 receives this parallel aligned laser beam 34 and directs it onto the source 20, in particular including the focusing onto the aforementioned pointlike focal volume arranged within the vacuum chamber 12.

[0102] As depicted, the shaping devices 60 and also the splitting device 46 depicted in FIG. 4, preserve the parallel alignment of the laser beam 34. Hence, the alterations and adaptations of the laser beam 34 provided by the shaping devices 60 and by the splitting device 46, have no impact onto the general optical imaging properties of the laser beam shaping device 40 determined by the collimation lens 42 and the focusing lens 44. In addition, this allows arranging these elements stationary, the collimation lens 42 and the focusing lens 44, within the laser beam shaping system 40 and in particular with respect to the end of the optical fiber 32 and the source 20.

[0103] In FIG. 1, an embodiment of a laser beam shaping device 40 is shown, in which a switchable size adapting element 64 forms the shaping device 60 of the laser beam shaping system 40. Such size adapting elements 64 are for instance beam compressors, beam expanders, free-form mirrors and/or matched pairs of defocusing lenses and focusing lenses. In particular, in the status depicted on the left, the size adapting element 64 is deactivated and essential no size alteration of the laser beam 34 is present. On contrast to that, on the right hand side of FIG. 1, the size adapting element 64 is activated and the laser beam 34 is compressed. This for instance increases a spatial energy density of the laser beam 34 on the target 20.

[0104] Additionally and as depicted by the slash-dotted lines, in this embodiment of the thermal laser evaporation system 10, the collimator lens 42 is integrated into the shaping device 60. An especially compact setup can therefore be provided.

[0105] Also FIG. 2 shows two embodiments of the thermal laser evaporation system 10 according to the invention. In contrast to FIG. 1, the shaping devices 60 are constructed as position adapting elements 66. Such position adapting elements 66 can be constructed for instance by using prisms, mirrors, diffractive optical elements and/or beam clipping elements.

[0106] As described above, the shaping devices 60 have no impact onto the general optical imaging properties of the laser beam shaping device 40 determined by the collimation lens 42 and the focusing lens 44. Hence the position alteration of the laser beam 34 provided by the position adapting elements 66 are directed by the focusing lens 44 onto the source 20, resulting in different impingement areas on the source 20.

[0107] Additionally, a driving apparatus 50 is mechanically connected to the position adapting element 66 to induce a movement of the respective position adapting element 66. This allows to actively alter and choose the impingement area of the laser beam 34 on the target 20, in other words, to scan the surface of the source 20 with the laser beam 34.

[0108] FIG. 3 shows the general possibility to combine several shaping devices 60, in this case a size adapting element 64 and a shape adapting element 62. As each of the shaping devices 60 preserves the parallel alignment of the laser beam 34 between the collimation lens 42 and the focusing lens 44, also a combination of two or more shaping devices 60 provides this preservation functionality. The effect of the shape adapting element 62 is depicted by presenting the cross sections 38 of the laser beam 34, whereby the shown shape adapting element 62 alters the cross section 38 of the laser beam 34 from circular to elliptical.

[0109] In FIG. 4, a splitting device 46 and its splitting element 48 are shown. In the splitting element 48, the laser beam 34 is split into two partial laser beams 36. Each partial laser beam 36 is independently directed onto the source 20 by the focusing lens 44. Shaping devices 60 (not shown) can also be used to alter parameters as for instance size, shape and/or positon of the partial laser beams 36, both individually and collectively, respectively.

TABLE-US-00001 Reference list 10 laser evaporation system 12 vacuum chamber 14 vacuum window 16 aperture 18 aperture opening 20 source 22 material 30 laser light source 32 optical fiber 34 laser beam 36 partial laser beam 38 cross section 40 laser beam shaping system 42 collimation lens 44 focusing lens 46 splitting device 48 splitting element 50 driving apparatus 52 upstream end 54 downstream end 60 shaping device 62 shape adapting element 64 size adapting element 66 position adapting element