The present invention relates to electrical circuit repair generally.
This application claims benefit of Israeli Patent Application No. 197349 entitled “A Method and System for Electrical Circuit Repair”, filed 2 Mar. 2009; the above noted prior application is incorporated herein by reference.
The following publications are believed to represent the current state of the art:
U.S. Pat. Nos. 4,752,455; 4,970,196; 4,987,006; 5,173,441 and 5,292,559;
“Metal deposition from a supported metal film”, Bohandy, B. F. Kim and F. J. Adrian, J. Appl. Phys. 60 (1986) 1538; and
“A study of the mechanism of metal deposition by the laser-induced forward transfer process”, F. J. Adrian, J. Bohandy, B. F. Kim, and A. N. Jette, Journal of Vacuum Science and Technology B 5, 1490 (1989), pp. 1490-1494.
The present invention seeks to provide an improved system and method for electrical circuit repair.
There is thus provided in accordance with a preferred embodiment of the present invention a method of repairing electrical circuits including employing a laser and at least one laser beam delivery pathway for laser pre-treatment of at least one conductor repair area of a conductor formed on a circuit substrate and employing the laser and at least part of the at least one laser beam delivery pathway for application of at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined conductor location.
In accordance with a preferred embodiment of the present invention the pre-treatment includes laser ablation. Preferably, the laser is operated at different power levels during the laser pre-treatment and the application to the donor substrate.
In accordance with a preferred embodiment of the present invention the pre-treatment includes pre-treatment of a substrate repair area and pre-treatment of a conductor repair area. Additionally, the laser ablation produces surface roughening of the substrate repair area and the conductor repair area. Additionally, the pre-treatment of the substrate repair area and the pre-treatment of the conductor repair area include different extents of surface roughening.
Preferably, the at least one conductor repair area is selected by automated optical inspection.
In accordance with a preferred embodiment of the present invention the method of repairing electrical circuits also includes employing the laser and the at least one laser beam delivery pathway for laser ablation of excess conductor material. Additionally, the excess conductor material is formed by material detached from the donor substrate. Additionally or alternatively, the laser ablation of excess conductor material is performed subsequent to the application of at least one laser beam to a donor substrate, which is in turn performed subsequent to the laser pre-treatment.
There is also provided in accordance with another preferred embodiment of the present invention a method of repairing electrical circuits including employing a laser and at least one laser beam delivery pathway for laser ablation of excess conductor material in at least one conductor repair area of a conductor formed on a circuit substrate and employing the laser and at least part of the at least one laser beam delivery pathway for application of at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined conductor location.
In accordance with a preferred embodiment of the present invention the laser ablation of excess conductor material effects repair of short circuits. Preferably, the laser is operated at different power levels during the laser ablation and the application to the donor substrate.
In accordance with a preferred embodiment of the present invention the method of repairing electrical circuits also includes surface roughening of the at least one conductor repair area. Preferably, the at least one conductor repair area is selected by automated optical inspection.
There is further provided in accordance with yet another preferred embodiment of the present invention a method of repairing electrical circuits including pre-treatment of at least one circuit substrate repair area of a circuit substrate and of at least one conductor repair area of a conductor formed on the circuit substrate and lying adjacent the at least one circuit substrate repair area and applying at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined circuit substrate location in the at least one circuit substrate repair area and to at least one predetermined conductor location in the at least one conductor repair area, thereby to at least partially overlap a portion of the conductor at the at least one conductor repair area and to form at least an extension of the conductor in the at least one circuit substrate repair area.
In accordance with a preferred embodiment of the present invention the pre-treatment includes laser ablation. Additionally, the laser ablation produces surface roughening.
Preferably, the pre-treatment and the applying are carried out by the same laser. Additionally, the pre-treatment and the applying are carried out by the same laser at different power levels.
In accordance with a preferred embodiment of the present invention the pre-treatment of the substrate repair area and of the conductor repair area are carried out by the same laser at different power levels. Additionally, the pre-treatment of the substrate repair area and of the conductor repair area include different extents of surface roughening.
Preferably, the at least one predetermined substrate location in the at least one substrate repair area and the at least one predetermined conductor location in the at least one conductor repair area are selected by automated optical inspection.
There is even further provided in accordance with still another preferred embodiment of the present invention a system for repairing electrical circuits including a laser and a laser beam delivery pathway, laser pre-treatment functionality utilizing the laser and at least part of the laser beam delivery pathway for laser pre-treatment of at least one conductor repair area of a conductor formed on a circuit substrate and conductor deposition functionality utilizing the laser and at least part of the laser beam delivery pathway for application of at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined conductor location.
There is yet further provided in accordance with another preferred embodiment of the present invention a system for repairing electrical circuits including a laser and a laser beam delivery pathway, excess conductor ablation functionality employing the laser and at least part of the laser beam delivery pathway for laser ablation of excess conductor material in at least one conductor repair area of a conductor formed on a circuit substrate and conductor deposition functionality employing the laser and at least part of the laser beam delivery pathway for application of at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined conductor location.
Preferably, the laser ablation of excess conductor material effects repair of short circuits.
There is still further provided in accordance with yet another preferred embodiment of the present invention a system for repairing electrical circuits including a laser and a laser beam delivery pathway, pre-treatment functionality employing the laser and at least part of the laser beam delivery pathway for treatment of at least one circuit substrate repair area of a circuit substrate and of at least one conductor repair area of a conductor formed on the circuit substrate and lying adjacent the at least one circuit substrate repair area and conductor deposition functionality employing the laser and at least part of the laser beam delivery pathway for application of at least one laser beam to a donor substrate in a manner which causes at least one portion of the donor substrate to be detached therefrom and to be transferred to at least one predetermined circuit substrate location in the at least one circuit substrate repair area and to at least one predetermined conductor location in the at least one conductor repair area, thereby to at least partially overlap a portion of the conductor at the at least one conductor repair area and to form at least an extension of the conductor in the at least one circuit substrate repair area.
The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
Reference is now made to
As seen in
A bridge 112 is arranged for linear motion relative to inspection location 104 along a first inspection axis 114 defined with respect to chassis 100. An optical head assembly 116 is arranged for linear motion relative to bridge 112 along a second inspection axis 118, perpendicular to first inspection axis 114.
In accordance with a preferred embodiment of the present invention, as seen in detail in
The system preferably also includes a control assembly 124, preferably including a computer 126 having a user interface 128 and including software modules operative to operate the inspection subassembly 120 and repair subassembly 122. Control assembly 124 preferably receives a defect location input from an automatic optical inspection system, not shown, such as a Discovery 8000 system, commercially available from Orbotech Ltd. of Yavne, Israel.
As seen in
In accordance with an embodiment of the invention, inspection subassembly 120 and repair subassembly 122 are arranged to at least partly share the same optical path along optical axis 154. The repair subassembly 122 includes a pulsed laser source 170, such as a passive Q-switch micro laser available from Teem Photonoics of Grenoble, France, operative to generate a pulsed laser beam 174. A suitable micro laser may be selected, for example, from laser heads operative to output beams at a wavelength of 532 nm or at 1064 nm, depending on the application. Pulsed beam 174 is passed through collimating optics 178, which may include two lenses 180 and 182, having focal lengths of 80 mm and −150 mm respectively, operative to collimate the laser beam 174 to a preferred spot size of 0.5-3.0 mm. Laser beam 174 is then reflected by mirror 184 and is then adjusted to a specific diameter by a beam expender 185, including multiple lenses 186 placed and adjusted for the required size of collimated output beam. Lenses 186 may include lenses such as a 28 mm plano-convex lens, a −10 mm biconcave lens and a 129 mm plano-convex lens, respectively. Laser beam 174 is then directed by a lens 188 to impinge on a two-axis fast steering mirror (FSM) 190, commercially available from Newport Corporation, and then passes through a lens 192, such as a 108 mm meniscus lens, a mirror 194 and a lens 196, such as plano convex 338 mm lens. Lenses 188, 192 and 196 maintain the position of the beam on the FSM 190, which is located after lens 188, and the input aperture of objective lens module 164. Beam 174 then impinges on beam splitter 198, which directs beam 174 through objective lens module 164 along axis 154. In accordance with a preferred embodiment of the invention, the lenses and optical components are arranged as shown and are suitably coated for operation in conjunction with the selected wavelength of laser beam 174.
Reference is now made to
In the stage shown in
The image is analyzed by control assembly 124 and is preferably compared to a reference, such as CAM data, thereby to confirm the existence and type of defect and to provide a detailed contour of the defect, preferably including definition of at least one conductor repair area 250 and at least one substrate repair area 252.
Turning now to
It is appreciated that the pre-treatment of conductor repair area 250 and of substrate repair area 252 are typically different. The general purpose of the pretreatment of conductor repair area 250 and substrate repair area 252 is to provide enhanced adhesion between a conductor material to be deposited and the existing conductor and substrate by surface roughening thereof, through laser ablation. For example, if a Q-switched microchip 30 milliwatt 532 nm laser producing sub-nanosecond pulses is employed, roughening of the substrate and conductor surfaces is achieved by using a spot size, typically, of 10 micron diameter, to produce an X-Y grid of trenches, typically having a depth of 4-6 microns. It is appreciated that depending on the composition of the substrate and of the conductor, the laser energy impinging on a unit area of the surface is varied, for example, by varying the scan speed of the laser beam on the surface or by adjusting the power of the impinging laser beam.
Reference is now made to
Donor substrate 270 is typically made of a material transparent to the laser's wavelength, which may be rigid, such as glass, or flexible, such as plastic, which is coated on one side with a thin layer of conductor material 272.
As seen in
Preferably the inspection subassembly is employed before and during deposition to monitor the X-Y position of the donor substrate 270 in order to ensure that conductor material 272 is present at all relevant times in a region covering all expected laser beam impingement locations thereon. This functionality is enabled by the fact that the laser and the inspection subassembly share the same focus.
It is a particular feature of the invention that the same laser which is used for surface roughening is also used for deposition. Here, deposition is achieved, for example, if a Q-switched microchip 30 milliwatt 532 nm laser producing sub-nanosecond pulses is employed, by using a spot of size typically of 10 micron diameter, to fill in conductor repair area 250 and substrate repair area 252.
Typically, following the completion of the deposition, a subsequent inspection of conductor repair area 250 and substrate repair area 252, similar to inspection described in reference to
Reference is now made to
As seen in
In the illustrated example shown in
In the stage shown in
The image is analyzed by control assembly 124 and is preferably compared to a reference, such as CAM data, thereby to confirm the existence and type of defect and to provide a detailed contour of the defect, preferably including definition of at least one conductor removal area, in the illustrated example, first and second excess conductor material regions 302 and 304.
Turning now to
It is appreciated that the laser ablation of first and second excess conductor material regions 302 and 304 is achieved, typically, if a Q-switched microchip 30 milliwatt 532 nm laser producing sub-nanosecond pulses is employed, by using a spot size, typically, of 5-20 microns diameter. It is appreciated that depending on the composition of the excess conductor material, the laser energy impinging on a unit area of the surface is varied, for example, by varying the scan speed of the laser beam on the surface or by adjusting the power of the impinging laser beam.
Preferably the inspection subassembly is employed before and during laser ablation to monitor the X-Y position of PCB 106 in order to ensure that the laser beam impinges on first and second excess conductor material regions 302 and 304 while not impinging on conductors 310, 312 and 314. This functionality is enabled by the fact that the laser and the inspection subassembly share the same focus.
It is a particular feature of the invention that the same laser which is used for surface roughening and deposition, as described with reference to
Typically, following the completion of the laser ablation, a subsequent inspection of PCB 106, similar to inspection described in reference to
It is appreciated that the laser ablation functionality described hereinabove with reference to FIGS. 4 and 5A-5C for performing laser ablation of excess conductor material regions 302 and 304 may also be used on the same PCB 106 together with the surface roughening and deposition functionalities described hereinabove with reference to
It is also appreciated that both the surface roughening and deposition functionalities, described hereinabove with reference to
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the present invention includes both combinations and subcombinations of various features described herein and improvements and variations which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.
Number | Date | Country | Kind |
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197349 | Mar 2009 | IL | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IL10/00106 | 2/7/2010 | WO | 00 | 7/26/2011 |