JP4056529B2 - Deposition equipment - Google Patents

Description

  The present invention relates to a film forming apparatus, and more particularly to a film forming apparatus using a molecular beam epitaxy apparatus (MBE apparatus) capable of generating various uniform thin films on a semiconductor substrate.

  As a method for producing a highly uniform coating on the substrate surface, a molecular beam epitaxy apparatus (MBE apparatus) is considered to be optimal and is actually used. According to the MBE apparatus, it is possible to perform the film formation from the so-called layer-by-layer control to the continuous film formation under an ultrahigh vacuum. FIG. 4 shows a conventional MBE apparatus, where 1 is a vacuum chamber having a main exhaust system 2, 3 is a Knudsen cell (K cell) mounted on the bottom of the vacuum chamber 1 for accommodating an evaporation source, and 4 is The shutter of the K cell 3, 5 is a substrate holding unit mounted on the top of the vacuum chamber 1, 6 is a substrate, 7 is the substrate heater provided in the holding unit 5, and 8 is the substrate 6 on its lower surface. A bottomed cylindrical substrate fixture for fixing, 9 is a substrate holder for attaching the substrate fixture 8 to the substrate holder 5, and 10 is a bottom portion of the vacuum chamber 1 for constituting a cold trap around the evaporation source. A liquid nitrogen shroud provided in the vacuum chamber 1, a sub chamber provided in a side portion of the vacuum chamber 1, a gate valve 12 capable of opening and closing the vacuum chamber 1 and the sub chamber 11 in an airtight manner, and 13, Provided in chamber 11 A sample replacement port, 14 is provided in the sub chamber 11, transport means for transporting the substrate 6 from the sub chamber 11 into the vacuum chamber 1, 15 is an auxiliary exhaust system provided in the sub chamber 11, 16 Is a reflection high-speed molecular beam diffractometer (RHEED) for observing the thin film of the substrate 6 being formed.

  The K cell 3 may be one or more as necessary, and an electron gun (ion gun) may be provided instead of the K cell 3.

  As the heater 7 of the conventional MBE apparatus, a disk-shaped plate heater is used to heat the substrate 6.

An example of the conventional MBE apparatus is disclosed in Patent Document 1.
JP-A-6-9297

  However, in the conventional film forming apparatus, it is difficult to rapidly heat the substrate, and even if the bottom thickness of the substrate fixture 8 is made as thin as possible, it is difficult to heat the substrate to a high temperature of 1000 ° C. or higher. It was.

  Therefore, it is possible to rapidly heat the substrate by combining a disk-shaped plate heater and other heating methods, for example, infrared light, laser light, electron gun, etc., but red light from the outside via an optical guide such as a mirror. Since external light or laser light is guided to irradiate the substrate, it is difficult to accurately irradiate a predetermined position on the substrate itself, and adjustment work takes a long time.

  In addition, the use of a combination of a disk plate heater, infrared light, and laser light has the disadvantage that temperature control is difficult and a uniform temperature distribution of the substrate cannot be obtained.

  The present invention eliminates the above-mentioned drawbacks.

  A film forming apparatus according to the present invention includes a vacuum chamber provided with an exhaust system, an evaporation source for film formation provided in the vacuum chamber, an opening provided in the vacuum chamber, and an attachment / detachment that hermetically closes the opening. A laser emitted from the semiconductor laser oscillator, comprising: a free lid; a laser light transmission window provided on the lid; a semiconductor laser oscillator provided on the outer surface of the lid; and a substrate holder provided on the inner surface of the lid. A film is formed on the substrate by irradiating light onto the substrate held by the substrate holder through the laser light transmission window and heating the substrate.

  The film forming apparatus of the present invention includes a laser diaphragm disposed between the substrate held by the substrate holder and the laser light transmission window.

  In addition, a heat equalizing plate is provided between the substrate held by the substrate holding portion and the laser light transmission window.

  Further, a laser diaphragm is disposed between the soaking plate and the laser light transmission window.

  The vacuum chamber further includes an infrared transmission window for a radiation thermometer.

  According to the present invention, the substrate can be rapidly heated without using a disk-shaped plate heater.

  Further, according to the present invention, the laser oscillator and the substrate holding unit can be fixed to the lid that is detachably and airtightly attached to the opening of the vacuum chamber, and the laser oscillator and the substrate holding unit can be adjusted by removing them from the vacuum chamber. Therefore, the position can be adjusted so that the laser beam can be accurately irradiated onto the substrate, the working time for the adjustment can be significantly shortened, and the substrate can be heated uniformly.

  In addition, since an infrared transmission window is provided in the vacuum chamber so that the substrate temperature can be measured with a radiation thermometer, the substrate temperature and temperature distribution can be measured in real time.

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

  In the film forming apparatus of the present invention, as shown in FIG. 1, instead of using the substrate holding unit 5 and the heater 7 at the top of the conventional vacuum chamber 1, an opening 17 is provided at the top of the vacuum chamber 1. The opening 17 is hermetically closed with a lid 19 having a laser light transmission window 18, and a continuous wave high-power direct semiconductor laser oscillator 21 is placed on the upper surface of the lid 19 via a laser oscillator holder 20 so that the laser light exit side is downward. And a substrate holder 23 is provided on the lower surface of the lid 19 via a support bar 22.

  Further, a laser beam diaphragm 24 is provided between the lower end of the support rod 22 and the substrate holder 23 in order to adjust the laser beam and the irradiation area as required.

  An infrared transmission window 25 having a size equal to or larger than the substrate size is provided at the lower end of the vacuum chamber 1, and a radiation thermometer 26 is provided below the transmission window 25, and the infrared transmission window 25 is formed by the radiation thermometer 26. Then, the temperature is measured from the infrared rays emitted from the substrate 6.

  The high-power direct semiconductor oscillator 21 preferably has a high output of 1 kW or more and has a uniform laser beam intensity over a wide area by passing through the optical lens system 30.

  Further, it is preferable that the laser oscillator holder 20 can adjust the height of the laser oscillator 21, and the support rod 22 can adjust the height of the substrate holder 23.

  The diaphragm 24 is preferably made of a material having good thermal conductivity, and the surface thereof is preferably ceramic coated.

  The laser light transmitting window 18 is preferably made of high-purity quartz, and the window diameter is preferably at least the diameter of the substrate.

  Further, as the material of the infrared transmitting window 25, barium fluoride, sapphire, calcium fluoride, germanium, zinc selenide and the like are preferable.

  Further, silicon, sapphire, zinc oxide or the like is used as a substrate, Zn, Mg, Ga or the like is used as an evaporation source, and O, N or the like is used as a radical source.

  Since the film forming apparatus of the present invention is configured as described above, the laser oscillator holder 20 and the support rod 22 are operated in a state where the lid 19 is removed from the vacuum chamber 1, so that the substrate 6 and the laser are operated. After the positional relationship of the oscillator 21 is accurately determined, the lid 19 is attached to the vacuum chamber 1, the vacuum chamber 1 is set to a high vacuum, laser light is emitted from the laser oscillator 21, and the laser light transmission window 18 is passed through. Then, the substrate 6 in the vacuum chamber 1 is irradiated and heated to form a film on the substrate 6.

  As shown in FIG. 2, depending on the type of substrate, the soaking plate 27 is fixed to the substrate holder 23, the substrate 6 is fixed to the lower portion of the soaking plate 27, and the upper surface of the soaking plate 27 is fixed. The substrate 6 may be heated by radiating heat and conduction heat from the soaking plate 27.

  As the soaking plate 27, it is preferable to use graphite, SiC, Inconel, Ni or the like.

  According to the present invention, for example, when a semiconductor laser having a power of 1.2 kW is used, the temperature of a 2-inch Si substrate can be raised to 1000 ° C. within one minute without using a disk-shaped plate heater.

  Further, according to the present invention, since the laser oscillator 21 and the substrate holder 23 are fixed to the lid 19 so that the position can be adjusted, the position can be adjusted so that the substrate 19 can be removed and the substrate can be accurately irradiated with laser light. The working time for adjustment can be remarkably shortened, and the substrate can be heated uniformly.

  Moreover, since the infrared transmission window 25 is provided in the lower part of the vacuum chamber 1 so that the substrate temperature can be measured with a radiation thermometer, the substrate temperature and the temperature distribution can be measured in real time.

  If necessary, the lid 19 having the laser oscillator and the substrate support rod can be replaced with a lid having a conventional disk-shaped plate heater.

  As shown in FIG. 3, a cylindrical optical path tube 28 reaching the upper part of the soaking plate 24 is provided at the lower part of the lid 19 of the first embodiment so as to guide the laser light to the substrate 6. Also good.

  Further, the substrate holder 23 provided at the lower end of the support bar 22 can be rotated around the support bar 22 located on the side of the sub chamber 11, and the substrate 6 is moved by the transport means 14 when rotated by 180 degrees. To be moved to the desired position.

  Reference numeral 29 denotes a rotatable shutter for controlling the intermittent film forming process.

It is a side view for description of the film-forming apparatus of the present invention. It is a side view for description of the other Example of the film-forming apparatus of this invention. It is a side view for description of another embodiment of the film forming apparatus of the present invention. It is a side view for description of a conventional film forming apparatus.

Explanation of symbols

1 Vacuum chamber 2 Main exhaust system 3 Knudsen cell (K cell)
4 Shutter 5 Substrate holder 6 Substrate 7 Heater 8 Substrate fixture 9 Substrate holder 10 Liquefied nitrogen shroud 11 Sub chamber 12 Gate valve 13 Sample exchange port 14 Transport means 15 Auxiliary exhaust system 16 Reflection high-speed molecular beam diffraction device (RHEED)
Reference Signs List 17 Opening 18 Laser Light Transmission Window 19 Lid 20 Laser Oscillator Holder 21 Continuous Oscillation High Power Direct Diode Semiconductor Laser Oscillator 22 Support Bar 23 Substrate Holder 24 Laser Light Aperture 25 Transmission Window 26 Radiation Thermometer 27 Heating Plate 28 Optical Path Tube 29 Shutter 30 Optical lens system

Claims (5)

  A vacuum chamber provided with an exhaust system; an evaporation source for film formation provided in the vacuum chamber; an opening provided in the vacuum chamber; a detachable lid that hermetically closes the opening; and The laser light transmission window provided, a semiconductor laser oscillator provided on the outer surface of the lid, and a substrate holding part provided on the inner surface of the lid, the laser light emitted from the semiconductor laser oscillator is passed through the laser light transmission window. A film is formed on the substrate by irradiating the substrate held by the substrate holding portion through heating and heating the substrate.   2. The film forming apparatus according to claim 1, further comprising a laser diaphragm disposed between the substrate held by the substrate holding portion and the laser light transmission window.   The film forming apparatus according to claim 1, further comprising a soaking plate disposed between the substrate held by the substrate holding unit and the laser light transmission window.   4. The film forming apparatus according to claim 3, wherein a diaphragm for laser is disposed between the soaking plate and the laser beam transmitting window.   5. The film forming apparatus according to claim 1, wherein the vacuum chamber further includes an infrared transmission window for a radiation thermometer.

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