WO2001014096A1

WO2001014096A1 - Multiple ultraviolet beam solid-state laser systems and methods

Info

Publication number: WO2001014096A1
Application number: PCT/US2000/015941
Authority: WO
Inventors: Yunlong Sun; Richard S. Harris
Original assignee: Electro Scientific Industries, Inc.
Priority date: 1999-08-20
Filing date: 2000-06-08
Publication date: 2001-03-01
Also published as: TW464579B; AU5478800A

Abstract

A multi-UV beam laser processing system uses at least first and second UV laser (30, 60, 90) beams (32, 34; 62, 64; 92, 94) from a single engine solid-state laser. The UV laser beams are directed to a work surface forsimultaneous processing resulting increased throughput. The solid-state laser (36, 66, 96) first generates a2nd harmonic green laser beam and then a non-linear crystal ('NLC') (42, 66, 98) generates a first UV beam. Because NLCs have limited conversion efficiency, the UV beam contains 'left over' fundamental and green laser power. Wavelength selective optics (108, 89, 108) separate the UV from the left over power, which is then converted by a second NLC (50, 114) into a second UV beam. Wavelength selective optics are used to separate out a second UV beam. The orientation of waveplates in front of each NLC controls their conversion efficiency so that the power levels of the first and second UV beams can be equalized or set to predetermined levels.

Description

MULTIPLE ULTRAVIOLET BEAM SOLID-STATE

LASER SYSTEMS AND METHODS

TECHNICAL FIELD This invention relates to laser systems and more particularly to single engine solid-state laser systems for emitting multiple ultraviolet ("UV") beams and methods of making and using same.

BACKGROUND OF THE INVENTION The etched circuit board ("ECB") industry is now utilizing laser beams to form smaller inter-layer connection pathways ("vias") required to produce ever increasing circuit densities. The typical laser employed is a Q-switched solid-state laser harmonically generating a UV beam that is directed toward the ECB.

Process speed, often referred to as process throughput, is a function of laser beam scanning speed, pulse repetition rate, pulse energy, and laser wavelength.

Although various laser wavelengths may be employed in processing ECBs, ultraviolet ("UV") wavelengths have many advantages. In particular, better processing quality and smaller via sizes became possible by employing UV wavelengths for processing conductor and dielectric layers. However, a factor limiting the available UV energy is the damage threshold of optical components employed to generate, direct, and focus the UV beam. Clearly, as laser beam energy levels are elevated, damage to these optical components increases. Generating the UV harmonics of a Q-switched, solid-state laser produces a UV beam that exhibits superior material processing capabilities in the ECB and numerous other industries. The "engine" of the laser is the resonant cavity (resonator) consisting of mirrors that enclose the lasing medium (Nd: YAG, YLF, YVO₄, etc.) and associated optics (Q-switch, polarizers, harmonic generating optics in the case of intra-cavity harmonic generation, etc.). Each engine typically requires an optical pump source for the lasing medium (arc lamp, laser diodes, etc.), a cooling system for the optical pump source, and control electronics. Frequency doubling the fundamental frequency of an IR engine generates the second harmonic "green" (2HG) and then frequency doubling again (quadrupling) generates the fourth harmonic UV (4HUV). Frequency mixing the IR and the 2HG (tripling) generates the third harmonic UV (3HUV). Conversion efficiency of the UV harmonic generation is approximately 10 to 15 percent. The UV component of the final output is separated from the green and IR components and directed to the optical train of the materials processing system while the unused green and IR components are dumped or trapped.

Existing laser-based ECB via processing systems either employ only one laser with a single laser beam or multiple lasers with different laser wavelengths. For example, U.S. Pat. No. 5,847,960 for MULTI-TOOL POSITIONING SYSTEM, which is assigned to the assignee of this application, describes a laser beam and workpiece positioning system capable of operating with a single CO₂ laser, a single IR Nd:YAG laser, a single UV Nd:YAG laser, or a combination of CO₂ and Nd:YAG lasers. Each solid-state laser beam is generated by a separate single engine laser. Increasing processing throughput has been mainly realized by increasing laser beam scanning speed, laser power, and pulse repetition rate.

Fig. 1 schematically illustrates a laser engine 9 consisting of a solid-state Nd:YAG rod 10 and an associated Q-switch 12 that generate an IR laser beam 14 within a cavity enclosed by resonator mirrors 16, 18, and 20. Mirrors 16, 18, and 20 are each highly reflective at the IR wavelength of 1,064 nanometer ("nm"), mirror 18 is highly reflective at the 2HG wavelength, and mirror 16 is also highly transmissive at the 2HG wavelength. The IR laser energy propagating in a forward direction from mirror 16 to 18 through a doubler 22 generates 2HG energy propagating in the forward direction. Because mirror 18 is highly reflective at both the 2HG and IR wavelengths, both the forward propagating IR and 2HG energy will be reflected in a reverse direction by mirror 18. The reverse propagating IR energy through doubler 18 generates 2HG energy propagating in the reverse direction. By carefully controlling the displacement between doubler 22 and mirror 18, the reflected reverse propagating 2HG constructively combines with the 2HG generated by the reverse propagating IR. The constructively combined 2HG laser beam is coupled out through mirror 16 as a first 2HG laser beam 24. If mirror 18 is also highly transmissive at the 2HG 532 nm wavelength, the forward propagating 2HG is directly coupled out at mirror 18 as a second 2HG laser beam 26. In this case, 2HG laser beams 24 and 26 have less power than would a single 2HG laser beam 24. Despite this prior laser work, there is no known prior work in which multiple UV beams are generated from a single engine laser and employed in ECB via and through hole processing applications.

What is needed, therefore, is a simple, less-costly, higher-efficiency UV laser system that is suitable for use in ECB processing applications and that does not cause damage to its associated optics.

SUMMARY OF THE INVENTION An object of this invention is, therefore, to provide a single engine laser apparatus and method for micro-machining an ECB with multiple UV laser beams that are directed toward the ECB by a positioner system. In a first preferred embodiment, the single solid-state laser emits a 2nd harmonic beam; a first nonlinear crystal receives the 2nd harmonic beam and produces a 4th harmonic beam including a residual 2nd harmonic beam; a first wavelength selective optical element receives the 4th harmonic beam and the residual 2nd harmonic beam, separates the residual 2nd harmonic beam from the 4th harmonic beam, and propagates the 4th harmonic beam toward the positioner system as a first UV beam. A second nonlinear crystal receives the residual 2nd harmonic beam and produces a second 4th harmonic beam and a second residual 2nd harmonic beam; and a second wavelength selective optical element receives the second 4th harmonic beam and the second residual 2nd harmonic beam, separates the second residual 2nd harmonic beam from the second 4th harmonic beam, and propagates the second 4th harmonic beam toward the positioner system as a second UV beam.

In a second preferred embodiment, the single solid-state laser emits first and second green beams; a first nonlinear crystal receives the first green beam and produces a first UV beam including a residual first green beam; a first wavelength selective optical element receives the first UV beam and the residual first green beam, separates the first residual green beam from the first UV beam, and propagates the first UV beam toward the positioner system. A second nonlinear crystal receives the second green beam and produces a second UV beam including a residual second green beam; and a second wavelength selective optical element receives the second UV beam and the residual second green beam, separates the second residual green beam from the second UV beam, and propagates the second UV beam toward the positioner system.

Process throughput of ECB via formation depends on laser beam scanning speed, laser wavelength, laser pulse repetition rate, and laser pulse energy. UV laser wavelengths also produce a higher quality finished via. The process of generating

UV laser energy through frequency doubling, tripling, or quadrupling is inherently inefficient leaving significant amounts of IR and green 2HG energy to be discarded. This invention utilizes the otherwise wasted green and IR energy to generate at least a second UV laser beam in another harmonic generation stage. The resulting two UV beams are tailored in their power levels to suit particular application needs.

Because some green and IR energy is still left unconverted, additional harmonic generation stages can be added to provide additional UV laser beams and further increase overall efficiency.

While UV lasers are advantageous for ECB processing, there are limits to how much UV power is available and maintainable. Factors limiting the available power include the power of the initial IR energy, the harmonic conversion efficiency, and the damage threshold of the NLCs and UV optics. In some applications too much UV power in a single beam can have adverse effects on processing quality and may cause workpiece damage. Increasing the laser pulse repetition rate and laser beam scanning speed mitigates workpiece damage, but there are scanning speed limits beyond which scanning accuracy diminishes.

This invention is advantageous because it increases the total usable UV laser power available from a single engine laser by generating multiple UV beams for concurrently processing multiple workpieces or multiple locations of a single workpiece at optimal power levels and scanning speeds. A laser beam and/or workpiece positioner employing multiple galvanometer scanning heads directs the multiple UV beams to multiple simultaneous material processing locations, thereby multiplying throughput while maintaining individual laser beam power levels below the damage threshold for their associated optical components and the NLCs. Therefore the system becomes more reliable and the cost is reduced relative to systems employing multiple lasers while workpiece processing throughput is increased.

This is particularly advantageous in an ECB processing system in which a dual beam positioner cuts either blind or through vias with improved process throughput. The single engine laser, dual UV beam ECB processing system can be combined with

CO₂ IR lasers so that the UV beams process conductor layers and the IR beams process dielectric layers, or the CO₂ IR laser provides rapid dielectric layer processing while the UV laser beams perform ECB trace cleaning or conductor layer drilling operations. An advantage of this invention is that it provides a high-efficiency UV laser that is suitable for use in ECB processing applications.

Another advantage of this invention is that it provides multiple UV laser beams from a single engine laser to increase ECB via formation throughput and simplify system complexity. Still another advantage of this invention is that it provides multiple UV laser beams having power levels that are substantially equal or proportional to a predetermined value.

Additional objects and advantages of this invention will be apparent from the following detailed description of preferred embodiments thereof that proceed with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic block diagram of a prior art laser that generates one or two green beams from a single engine solid-state IR laser.

Fig. 2 is a schematic block diagram of a first embodiment of a high-efficiency laser of this invention that generates two 4HUV laser beams from a single engine 2HG generating solid-state laser.

Fig. 3 is a schematic block diagram of a second embodiment of a high- efficiency laser of this invention that generates two 4HUV laser beams from a single engine solid-state laser generating two 2HG "green" beams.

Fig. 4 is a schematic block diagram of a third embodiment of a high- efficiency laser of this invention that generates two 3HUV laser beams from a single engine solid-state IR laser. Fig. 5 is an oblique pictorial view showing a dual-beam laser machining system suitable for use with this invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 2 shows a first preferred embodiment of a high-efficiency UV laser 30 of this invention that generates at least first and second UV laser beams 32 and 34 from a single engine, Q-switched, solid-state laser 36 that is conventionally configured to emit about an eight watt 2HG green beam 38. Laser 36 includes an IR generating laser that may be, for example, a 1,064 nm Nd:YAG or Nd:YVO₄ laser, or a 1,053 nm or 1,047 nm Nd:YLF laser. The Q-switch, 2HG generating NLC, and resonator mirrors are all part of laser 36. Assuming a 1,064 nm Nd:YAG laser is employed to generate a 532 nm green laser beam 38, a first waveplate 40 rotates the polarization of green beam 38 to an orientation suitable for generation by a first NLC 42 of a 4HUV, 266 nm UV laser beam 44. Because of the typical 10 to 15 percent conversion efficiency of NLC 42, UV laser beam 44 contains about one watt of 266 nm UV power and about seven watts of "left over" green power (not counting optical losses). The left over green power is referred to as a residual green laser beam 45. A wavelength selective optical element 46 reflects UV laser beam 44 to propagate first UV laser beam 32.

The seven watts of residual green laser beam 45 is passed through wavelength selective optical element 46 and a second waveplate 48, which rotates the polarization of residual green laser beam 45 to an orientation suitable for generation by a second NLC 50 of another 4HUV, 266 nm laser beam 52. Another wavelength selective optical element 54 reflects the UV to propagate second UV laser beam 34. Because of the typical 10 to 15 percent conversion efficiency of second NLC 50, laser beam 52 contains less than one watt of 266 nm UV power and about six watts of left over green power (again not counting optical losses), which is referred to as residual green laser beam 56.

Clearly, this harmonic generation process can be cascaded as needed to suit particular applications. First and second waveplates 40 and 48 can be oriented to change the harmonic generation efficiency of first and second NLCs 42 and 50, thereby setting the power levels of first and second UV laser beams 32 and 34 to predetermined or equalized values. This can be accomplished without any additional UV beam shutters or controls.

Skilled workers will understand that laser 36 may operate at different than the above-described power levels and that a variety of beam focusing and correction techniques may be employed in the different UV conversion stages to generate predetermined power levels and beam sizes for first and second UV laser beams 32 and 34.

Fig. 3 shows a second preferred embodiment of a high-efficiency UV laser 60 of this invention that generates first and second UV laser beams 62 and 64 from a single engine, Q-switched, 2HG Nd:YAG laser 66 that is configured similar to laser 9 of Fig. 1. Laser 66 generates first and second green laser beams 76 and 80, which are further directed through respective first and second waveplates 82 and 84 to rotate the polarization of green beams 76 and 80 into orientations suitable for generation by respective first and second NLCs 86 and 87 of 4HUV, 266 nm laser beams 62 and

64. Wavelength selective optical elements 88 and 89 are employed to separate the UV and green components into laser beams 62 and 64 and residual green laser beams 67 and 68.

In a manner similar to the first embodiment, various techniques of mirror design, waveplate orientation, focusing, and correction optics may be employed to tailor first and second UV laser beams 62 and 64 to particular application requirements. The first and second embodiments of this invention may be combined by cascading additional waveplate, NLC, and mirror stages to convert left over power present in residual green laser beams 67 and 68 to additional UV laser beams. Fig. 4 shows a third preferred embodiment of a high-efficiency UV laser 90 of this invention that generates at least first and second UV laser beams 92 and 94 from a single engine, Q-switched, IR laser 96 that emits an IR laser beam 97 that is frequency doubled by a first NLC 98 to generate about an eight watt, 2HG laser beam 100. NLC 98 also passes a residual IR laser beam 102. IR laser 96 may include, for example, a 1,064 nm Nd:YAG or Nd:YVO₄ laser, or a 1,053 nm or

1,047 nm Nd:YLF laser.

Assuming, for example, that IR laser 96 produces a 1,064 nm Nd:YAG laser beam and a 2HG beam 100 having a 532 nm wavelength. A second NLC 104 mixes together 2HG beam 100 and residual IR laser beam 102 to generate a 3HUV, 355 nm UV laser beam 106, which is reflected by a wavelength selective optical element 108 to propagate first UV laser beam 92. Because second NLC 104 has a finite mixing efficiency, it passes a residual IR laser beam 110 and a residual 2HG laser beam 112, both of which propagate through wavelength selective optical element 108 and are received by a third NLC 114. Third NLC 114 mixes together residual IR laser beam 110 and residual 2HG laser beam 112 to generate another 3HUV, 355 nm UV laser beam 116, which is reflected by a wavelength selective optical element 118 to propagate second UV laser beam 94. Because third NLC 114 has a finite mixing efficiency, it also passes a residual IR laser beam 120 and a residual 2HG laser beam 122, both of which propagate through wavelength selective optical element 118 and are either received by yet another NLC or are dumped. As in the first and second embodiments of this invention, waveplates can be added to set the powers of first and second UV laser beams 92 and 94 to predetermined values. The NLCs of this invention may be formed from any of BBO, LBO, or CLBO crystals, or from any other suitable UV generating NLC material.

Fig. 5 shows a representative application system utilizing the dual UV laser beams generated by any of the embodiments of this invention, in which a multi-head positioner 150 simultaneously processes vias on ECBs 152A and 152B, which may be separate ECBs or different portions of the same ECB. Multi-head positioner 150 may be based on four head positioner described in U.S. Pat. No. 5,847,960 for MULTI-TOOL POSITIONING SYSTEM, which is assigned to the assignee of this application. ECBs 152 A and 152B are fixtured and carried on a Y-axis slow stage

153 and fast X-Y stages 154A and 154B are carried on an X-axis slow stage 155. Of course, the roles of slow stages 153 and 155 may be reversed.

If more than two laser beams are available for processing, additional ECBs and associated fast stages 154 can be added. However, as the number of fast stages

154 carried on slow stage 155 increases, their accumulated mass becomes increasingly difficult to accelerate. Therefore, the practical number of fast X-Y stages 154 is limited to four, although the number may vary with positioner types and applications.

ECBs 152A and 152B are processed by associated laser beams 156A and 156B that are directed toward associated fast stages 154 A and 154B by way of associated mirrors 158A and 158B. Fast X-Y stages 154A and 154B deflect laser beams 156A and 156B to target locations in processing fields 162A and 162B located on associated ECBs 152A and 152B. Laser beams 156A and 156B are preferably UV laser beams generated by any of the high-efficiency UV lasers 30, 60, and 90 of this invention. Video cameras 160A and 160B are positioned on X-axis slow stage 155 for viewing associated processing fields 162 A and 162B, sensing the alignments, offsets, rotations, and dimensional variations of ECBs 152A and 152B, and aiming and focusing laser beams 156A and 156B.

EXAMPLE A typical application of this invention is the processing of blind or through vias and pathways in multilayer ECBs. Multilayer ECBs are typically manufactured by registering, stacking together, laminating, and pressing multiple 0.05 mm to

0.08 mm thick circuit board layers. Each layer typically contains a different interconnection pad and conductor pattern, which after processing constitutes a complex electrical component mounting and interconnection assembly. ECB component and conductor density continues to increase and tracks the densities of integrated circuits. Therefore, the requirement for making smaller, high quality ECB vias is changing proportionally.

Processing blind vias presents a difficult challenge for any via processing tool because of the tight depth, diameter, and positioning tolerances involved. This is because blind vias are typically processed through one or more conductor layers (e.g., copper, aluminum, gold, nickel, silver, palladium, tin, and lead), through their intervening dielectric layers (e.g., polyimide, FR-4 resin, benzocyclobutene, bismaleimide triazine, cyanate ester-based resin), but not through a predetermined final conductor layer. The resulting multi-layer vias are plated with a conductive material to electrically connect the multiple conductor layers. Multi-head positioner 150 is configured as an ECB blind via cutting apparatus in which laser beams 156A and 156B are UV laser beams having a wavelength less than about 400 nm.

UV laser beams 156A and 156B are capable of concurrently cutting one or more conductor and intervening dielectric layers of ECBs 152A and 152B. However, the laser power levels and pulse repetition rates must be carefully controlled to prevent unacceptable damage to the final conductor layer. Therefore, UV laser beams 156 A and 156B are controlled to cut through the one or more conductor layers and a portion of the final dielectric layer. Thereafter, the laser power levels and pulse repetition rates are adjusted to process the remaining dielectric layer without damaging the final conductor layer.

Some ECB processing applications require cutting relatively large hole diameters of about 200 micrometers or less. Multi-head positioner 150 can move UV laser beams 154 A and 154B in a spiral or circular path to cut such holes.

Skilled workers will recognize that portions of this invention may be implemented differently from the implementations described above for preferred embodiments. For example, the laser systems may employ other than the above- described power levels and wavelengths; positioner 150 may employ different optical components and paths; and a single engine laser may be employed, as required by particular applications, to generate multiple IR, green, and UV beams. ECB dielectric layer processing may also be enhanced by providing an additional IR laser beam or beams from a CO₂- or YAG-based IR laser together with the above- described multiple UV beams from a single engine laser. Such enhancements may include quickly cutting a large diameter home in a dielectric layer, and cutting the dielectric layer without damaging any underlying conductor layer. In such processing, the CO₂ laser may have a wavelength ranging from about 9.3 micrometers to about 10.6 micrometers, or the YAG laser may have a wavelength of about 1,064 nanometers.

It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.

Claims

We Claim:

1. A single engine laser apparatus for micro-machining an etched-circuit board ("ECB") with multiple ultraviolet ("UV") laser beams that are directed toward the ECB by a positioner system, comprising: a solid-state laser emitting a 2nd harmonic beam; a first nonlinear crystal receiving the 2nd harmonic beam and producing a 4th harmonic beam including a residual 2nd harmonic beam; a first wavelength selective optical element receiving the 4th harmonic beam and the residual 2nd harmonic beam, separating the residual 2nd harmonic beam from the 4th harmonic beam, and propagating the 4th harmonic beam toward the positioner system as a first UV beam; a second nonlinear crystal receiving the residual 2nd harmonic beam and producing a second 4th harmonic beam and a second residual 2nd harmonic beam; and a second wavelength selective optical element receiving the second 4th harmonic beam and the second residual 2nd harmonic beam, separating the second residual 2nd harmonic beam from the second 4th harmonic beam, and propagating the second 4th harmonic beam toward the positioner system as a second UV beam.

2. The apparatus of claim 1 in which the first and second nonlinear crystals include at least one of BBO, LBO, and CLBO.

3. The apparatus of claim 1 in which the first and second UV beams each have a wavelength ranging from about 261 nanometers to about 266 nanometers.

4. The apparatus of claim 1 in which the first UV beam has a first power level, the second UV beam has a second power level, and the apparatus further includes first and second waveplates for rotating a polarization angle of the respective

2nd harmonic beam and residual 2nd harmonic beam to adjust a harmonic generation efficiency of the respective first and second nonlinear crystals such that the first and second power levels are adjustable to predetermined or equalized power levels.

5. A single engine laser apparatus for micro-machining an etched-circuit board ("ECB") with multiple ultraviolet ("UV") laser beams that are directed toward the ECB by a positioner system, comprising: a solid-state laser emitting first and second green beams; a first nonlinear crystal receiving the first green beam and producing a first

UV beam including a residual first green beam; a first wavelength selective optical element receiving the first UV beam and the residual first green beam, separating the first residual green beam from the first UV beam, and propagating the first UV beam toward the positioner system; a second nonlinear crystal receiving the second green beam and producing a second UV beam including a residual second green beam; and a second wavelength selective optical element receiving the second UV beam and the residual second green beam, separating the second residual green beam from the second UV beam, and propagating the second UV beam toward the positioner system.

6. The apparatus of claim 5 in which the first and second nonlinear crystals include at least one of BBO, LBO, and CLBO.

7. The apparatus of claim 5 in which the first and second UV beams each have a wavelength ranging from about 261 nanometers to about 266 nanometers.

8. The apparatus of claim 5 in which the first UV beam has a first power level, the second UV beam has a second power level, and the apparatus further includes first and second waveplates for rotating a polarization angle of the respective first and second green beams to adjust a harmonic generation efficiency of the respective first and second nonlinear crystals such that the first and second power levels are adjustable to predetermined or equalized power levels.

9. A single engine laser apparatus for micro-machining an etched-circuit board ("ECB") with multiple beams of ultraviolet ("UV") laser energy that are directed toward the ECB by a positioner system, comprising: a solid-state laser emitting infrared ("IR") and 2nd harmonic beams; a first nonlinear crystal receiving the IR and 2nd harmonic beams and generating a 3rd harmonic beam including residual IR and 2nd harmonic beams; a first wavelength selective optical element receiving the 3rd harmonic beam and the residual IR and 2nd harmonic beams, separating the residual IR and 2nd harmonic beams from the 3rd harmonic beam, and propagating the 3rd harmonic beam toward the positioner system as a first ultraviolet ("UV") beam; a second nonlinear crystal receiving the residual IR and 2nd harmonic beams and producing a second 3rd harmonic beam and second residual IR and 2nd harmonic beams; and a second wavelength selective optical element receiving the second 3rd harmonic beam and the second residual IR and 2nd harmonic beams, separating the second residual IR and 2nd harmonic beams from the second 3rd harmonic beam, and propagating the second 3rd harmonic beam toward the positioner system as a second UV beam.

10. The apparatus of claim 9 in which the first and second nonlinear crystals include at least one of BBO, LBO, and CLBO.

11. The apparatus of claim 9 in which the first and second UV beams each have a wavelength ranging from about 349 nanometers to about 355 nanometers.

12. The apparatus of claim 9 in which the first UV beam has a first power level, the second UV beam has a second power level, and the apparatus further includes at least one waveplate for rotating a polarization angle of at least one of the IR beam, the 2nd harmonic beam, the residual IR beam, and the 2nd harmonic beam to adjust a harmonic mixing efficiency of at least one of the first and second nonlinear crystals such that the first and second power levels are adjustable to predetermined or equalized power levels.

13. In an etched-circuit board ("ECB") processing system, a method for micro-machining an ECB having a conductor layer and a dielectric layer with beams of laser energy that are directed toward the ECB by a multi-head positioner, comprising: providing a solid-state single engine laser emitting at least first and second ultraviolet ("UV") beams; directing the first and second UV beams toward first and second target locations on the ECB; setting the first and second UV beams to a first set of operating conditions; cutting through the conductor layer with the first and second UV beams at the first and second target locations; setting the first and second UV beams to a second set of operating conditions; and processing the dielectric layer with the first and second UV beams at the first and second target locations.

14. The method of claim 13 in which the first and second UV beams have a wavelength ranging from about 261 nanometers to about 355 nanometers.

15. The method of claim 13 in which the first and second sets of operating conditions include setting a power level and a pulse repetition rate of the first and second UV beams.

16. The method of claim 13 in which the multi-head positioner is capable of directing four UV beams toward four target locations on the ECB, and the method further includes splitting each of the first and second UV beams into two additional UV beams each having a predetermined power level, and directing the first, second, and two additional beams toward respective first, second, third, and fourth target locations on the ECB.

17. The method of claim 13 further including providing a CO₂ laser emitting an infrared ("IR") beam having a wavelength ranging from about 9.3 micrometers to about 10.6 micrometers, or providing a YAG laser emitting an IR beam having a wavelength of about 1,064 nanometers.