Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
  • H05K3/027—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed by irradiation, e.g. by photons, alpha or beta particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
  • B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
  • B23K26/0624—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses using ultrashort pulses, i.e. pulses of 1ns or less
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/36—Removing material
  • B23K26/40—Removing material taking account of the properties of the material involved
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the groups H01L21/18 - H01L21/326 or H10D48/04 - H10D48/07
  • H01L21/4814—Conductive parts
  • H01L21/4846—Leads on or in insulating or insulated substrates, e.g. metallisation
  • H01L21/485—Adaptation of interconnections, e.g. engineering charges, repair techniques
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/08—Non-ferrous metals or alloys
  • B23K2103/10—Aluminium or alloys thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/16—Composite materials, e.g. fibre reinforced
  • B23K2103/166—Multilayered materials
  • B23K2103/172—Multilayered materials wherein at least one of the layers is non-metallic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Definitions

• the invention relates to a laser micro-beam machine for working on thin-filmed objects, such as for example integrated electronic circuits, in particular for cutting thin films of a thermally conductive material.
• the object of the present invention is in particular to avoid this drawback, and to improve this machine so as to allow a very fine and very precise cut of thin layers made in particular of materials which are good conductors of heat.
• the invention proposes a laser micro-beam machine of the aforementioned type, comprising a laser coupled to a mrcr ⁇ s " cope making it possible to focus the point of impact of the laser beam on an object with thin layers, such as an integrated electronic circuit for example, characterized in that the laser is a laser pulsed, has short duration pulses and low average power.
• the duration of the pulses is between a few nanoseconds and a few hundred nanoseconds approximately, their repetition frequency is between 100 Hz and a few kHz approximately, the energy of the laser beam is approximately 20 to 100 micro ⁇ joules per pulse, while the average power of the laser is around 20 to 100 mW. Thanks to the very short duration of the pulses emitted by the laser, the heat remains confined in an area localized at the point of impact of the laser beam on a thin layer, so that one can achieve a very fast and precise cut of this thin layer by sublimation of the material of this thin layer, without risk of damaging the surrounding areas, and in addition the energy expended to make this cut is much lower than the corresponding energy required in the case of use of a continuous laser.
• the continuous laser used in the machine described in French patent 2 608 484 has a power of about Watt, while the pulsed laser used in the context of the present invention has an average power of about 40 to 50 mW, about twenty times lower.
• the laser is made of solid state components, of the YAG or YLF type, and is pumped by a flash lamp or a laser diode.
• a laser of this type is reliable, has a very long service life, and reduced servitudes.
• the laser is associated with a frequency doubler, so as to emit a beam of wavelength of about 530 nm, which allows, on the one hand, good absorption by silicon and, on the other hand, to reduce the diameter of the point of impact of the laser beam on the object, and therefore to obtain better cutting finesse.
• This machine is for example of the type described in French Patent 2,608,484 and then essentially comprises a laser 10 at the outlet of which is provided an optical system 12 leading to a microscope 14 of which an objective 16 is oriented towards an object 18 with thin layers.
• Lighting means 20 are suitably connected to the microscope 14, which is itself connected to display means 22 making it possible to observe the action of the laser microbeam on the object 18.
• Control means 24 laser 10 and the displacement of the laser micro-beam on the surface of the object 18 are also provided.
• the laser beam transmission path comprising the optical system 12 and the microscope 14, the lighting path connecting the microscope 14 to the lighting means 20, and the display path, connecting the microscope- 14 by means of vi ⁇ sualisation 22, are carried by the same rigid and non-deformable plate, mounted on a fixed frame.
• the generator used is of the pulse type, such as for example a laser with bars Ud + YAG or YLF, pumped by a flash lamp or a laser diode, and having an average power of 1 40 mW, with an energy of 40 J per pulse, the pulse repetition frequency being of the order of 1 kHz.
• Lasers of this type have a small footprint, reduced servitudes, and a very long lifetime, due to their realization with components in the solid state. They can be equipped with a frequency doubler (designated here by the reference 26) which is a non-linear cris ⁇ tal placed in the laser cavity, which allows to emit a beam having a wavelength approximately 530 nm for better absorption by the silicon (in the case of processing of integrated circuits) and finer focusing of the laser micro-beam on the surface of the object 18 (the diameter of the point of impact of the laser micro-beam on the object 18 being less than the micrometer).
• a frequency doubler designated here by the reference 26
• the reference 26 is a non-linear cris ⁇ tal placed in the laser cavity, which allows to emit a beam having a wavelength approximately 530 nm for better absorption by the silicon (in the case of processing of integrated circuits) and finer focusing of the laser micro-beam on the surface of the object 18 (the diameter of the point of impact of the
• Q SWITCH acousto-optical modulator 28
• the machine according to the invention allows precise and fine cuts of very conductive materials such as gold or aluminum, by sublimation of these materials.
• very conductive materials such as gold or aluminum
• the heating between neighboring parts of the surface of the object 18, which is linked to the average power deposited, is very low compared to the case of the use of a continuous laser.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Plasma & Fusion (AREA)
• Ceramic Engineering (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Power Engineering (AREA)
• Laser Beam Processing (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9393337

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (2)

• 1990
  • 1990-02-02 FR FR9001226A patent/FR2657803A1/fr active Granted
• 1991
  • 1991-01-31 WO PCT/FR1991/000061 patent/WO1991011288A1/fr unknown

Patent Citations (2)

Non-Patent Citations (2)

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