JP3974919B2 - Laser deposition system - Google Patents

Description

  The present invention relates to a film forming apparatus using a laser, and more particularly to a film forming apparatus using a laser capable of generating various uniform thin films on a substrate such as a semiconductor substrate.

  FIG. 6 shows a conventional film forming apparatus using a laser, wherein 1 is a vacuum chamber, 2 is a substrate such as a semiconductor substrate, and 3 is a substrate placing portion provided in the vacuum chamber 1 for placing the substrate 2. Is a laser light incident process window provided on the ceiling of the vacuum chamber 1, 5 is a mass flow for introducing a stable gas into the vacuum chamber 1, and 6 is an exhaust for exhausting the air in the vacuum chamber 1. A pump 7 is a pressure control valve for controlling the degree of vacuum in the vacuum chamber 1.

In the conventional laser deposition apparatus, a laser beam is guided to the vicinity of the process window 4 by an optical fiber (not shown) to form, for example, an insulating film on a substrate, and the process window is guided from the tip of the optical fiber. A laser beam is irradiated onto the substrate 2 placed on the substrate placement unit 3 in the vacuum chamber 1 via 4. As such conventional laser-based film forming apparatuses, there are those described in Patent Document 1 and Patent Document 2.
Japanese Patent Laid-Open No. 2002-252181 (FIG. 1) JP 2000-87223 A (FIG. 1)

  However, in the above conventional laser film forming apparatus, the laser beam applied to the substrate is not defocused, so that a large area semiconductor substrate having a diameter of 2 inches cannot be uniformly heated at a desired temperature increase rate. In addition, when the laser beam was defocused, the amount of laser beam leaking from the substrate increased, resulting in poor thermal efficiency and uniform heating.

  The present invention eliminates the above-mentioned drawbacks.

The laser film deposition apparatus of the present invention mounts a substrate in a vacuum chamber, directly irradiates the substrate with high-power semiconductor laser light from the outside of the vacuum chamber through the window of the vacuum chamber, and heats the substrate. In the film forming apparatus, the laser beam irradiated to the substrate is defocused light, and a reflector with a total reflection coating that can change the curved shape is provided behind the substrate in the vacuum chamber to reflect the laser beam leaking from the substrate. The position and curvature of the reflector can be adjusted so that a desired position on the substrate can be irradiated .

  The effect of this invention is shown below.

  (1) Since the leaked laser light is picked up by the reflector and applied to the substrate, uniform heating can be performed with high thermal efficiency.

  (2) Since the position and curvature of the reflector can be arbitrarily changed, a desired temperature distribution can be given to the substrate.

  (3) The substrate can be rapidly heated.

  (4) There is no possibility that the laser beam directly hits the apparatus, and the apparatus is less damaged.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 and FIG. 2 each show a film forming apparatus using a laser according to the present invention. Laser light emitted from a continuous wave high power semiconductor laser oscillator 8 into a vacuum chamber 1 is passed through an optical lens unit 10. The defocused light 9 is used to irradiate the substrate 2 in the vacuum chamber 1 directly or through a soaking plate (not shown) to heat the substrate 2. A reflector 11 having a curved surface is provided behind the substrate platform 3, and the reflector can adjust the position and curvature of the curved reflector by external control, and irradiates the reflected light of the reflector 11 to a desired position on the substrate. I will do it.

  As the reflector 11, a total reflection coating film is formed on the surface of heat-resistant glass, quartz, or a metal having good thermal conductivity. As the reflective film, it is preferable to form ITO (transparent conductive film) or a metal having good thermal conductivity by vapor deposition. The reflective function can be enhanced by depositing several kinds of metals on top of each other. Examples of the deposited metal include Al, Cr, Inconel, Ni, Au, Ag, Pt, Mo, W, Cu, and Rh.

  Note that silicon, sapphire, zinc oxide or the like can be used as the substrate, and graphite, SiC, Inconel, or Ni can be used as the soaking plate.

  In addition, the reflector 11 in the present invention is formed of multiple pieces of metal plate or heat-resistant glass or quartz having a reflective film formed on the surface as shown in FIGS. 3 and 4, and has a dome shape with a hole in the center. The position and curvature of the dome can be changed from R1 to R2 as shown in FIGS. 4 to 5 by external control.

  Further, an infrared transmission window 12 having a size equal to or larger than the substrate size is provided at a position facing the laser beam at the bottom of the vacuum chamber 1, and the infrared thermometer 13 is caught and the temperature is measured by the radiation thermometer 13.

  Silicon, sapphire, zinc oxide or the like can be used as the substrate, and graphite, SiC, Inconel, or Ni can be used as the soaking plate.

  As described above, in the film forming apparatus using the laser according to the present invention, leakage laser light, for example, laser light deviated from the substrate irradiation surface among the defocused light emitted toward the substrate 2 and the substrate 2 are transmitted. A part of the laser light is picked up by the curved reflector 11 provided behind the substrate, reflected toward the substrate by the reflective film on the surface of the curved reflector, and irradiated to the substrate, so that the heating efficiency of the substrate 2 is improved. The improvement and uniform heating of the substrate are possible, and rapid heating becomes possible.

  The laser used in the present invention is a continuous-wave high-power semiconductor laser device having a high output of 1 kW or more and having a uniform laser light intensity over a wide area. In the present invention, the laser light applied to the substrate is defocused laser light, but it can also be applied to parallel light.

It is a front view of the film-forming apparatus by the laser of this invention. It is a front view of the film-forming apparatus by the laser of the other Example of this invention. It is a top view of the reflector of the film-forming apparatus by the laser of this invention. It is a side view of the reflector shown in FIG. It is explanatory drawing which shows the curvature change of the reflector shown in FIG. It is explanatory drawing of the film-forming apparatus by the conventional laser.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Board | substrate 3 Board | substrate mounting part 4 Process window 5 Mass flow 6 Exhaust pump 7 Pressure control valve 8 Continuous oscillation high output semiconductor laser oscillator 9 Laser beam (defocus light)
DESCRIPTION OF SYMBOLS 10 Optical lens part 11 Reflector 12 Infrared transmission window 13 Radiation thermometer

Claims (1)

In a film forming apparatus in which a substrate is mounted in a vacuum chamber, the substrate is heated by directly irradiating the substrate with high-power semiconductor laser light from the outside of the vacuum chamber through the window of the vacuum chamber, and a film is formed on the substrate. The laser beam to be irradiated is defocused light, and a reflector with total reflection coating that can change the curved surface shape is provided behind the substrate in the vacuum chamber so that the laser beam leaking from the substrate can be reflected and irradiated to a desired position on the substrate. A film forming apparatus using a laser , wherein the position and curvature of the reflector can be adjusted .

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