Spectrometrical Systems for Control of Spectrum and Thickness of Coatings

Spectrometrical systems for control of spectrum and thickness of coatingsThe system is designated to equip vacuum technological plants for deposition of coatings with sputtering units of different type (magnetron, arc, thermal, electron-beam, etc.). The usage of the system is especially effective in the technology of creation of sophisticated optical coatings (antireflection, reflection, interference light filters), its informing possibilities surpass much the possibilities of the known systems of control of a coating reflection coefficient on the fixed wave length of the systems of control of a coating thickness (for example, on piezoelectric transducers).

The system is designated, first of all, to control the spectral coefficient of reflection of samples surface (products, certifier) moving during the process of deposition of film coatings with assistance of the devices go-round or linear type (or immovable). As the basic information there is a diagram on the computer monitor display in the real time showing dependence of a coating reflection coefficient (in %) on a wave length within the limits of the working spectral range. The system also provides the express after-work control and registration (with outlet of the results on the printer) of the reflection of the spectrum and the spectrum of transparency of a produced coating.

Structural system of the spectrometrical systems for control of spectrum and thickness of coatings

  1. Structural system of the spectrometrical systems for control of spectrum and thickness of coatingsSounding radiation source.
  2. Polychromator.
  3. Detector.
  4. Computer.
  5. Optofiber for reception of light reflected from a sample.
  6. Optofiber for transmission of sounding light on a sample.
  7. Objective.
  8. Sample.
  9. Optofiber for reception of sounding light.
  10. Software.

The device uses the standard SL 40 polychromator.

Polychromator specifications

  • Spectral range, nm - 300-1100.
  • Dispension, nm/mm - 55.
  • Spectral allowance, nm - less than 2,5.
  • Dimensions, mm - 80*150*250.
  • Fiber-optical inlets, pcs - to 3.

Spectre registration parameters

  • Registration channels number - 1024.
  • Number of spectrums per one taking - 1-255.
  • Integration time to registrate one spectrum - 0,001 c - 10 minutes.
  • Delay of registration start after actuation of the outer device (switching shutter on) - 1 ms - 60 s.
  • Pause between spectrums next in time - 1 ms - 1 min.
  • Perceptibility under E=7 keV - 200 fotons/count off ACP.
  • Dynamic range - not worse than 1/30000.

Detector parameters

  • Homogeneity of perceptibility by diodes (under calibrating) - not worse than ±1%.
  • Temperature of detector - 30° C.
  • Analog-to-digital conversion - 16 bits.
  • Microprocessor - DS5000, 8 bits RAM/ROM 32K.
  • Time of transuding - 6 ms/diode.
  • Total time of coding - 7 ms.
  • Interface to contact with computer - parallel EPP.

Main specifications

  • Working spectral range of system (recommended) from 380 to 860 nm (may be changed, moved into the ultra-violet field or amended with the ultra-violet range by a customer's order).
  • Spectral allowance - not worse than 1,5 nm.
  • Control of the system work and indication of results are effected with an assistance of a computer. Demands to a computer processor not lower P-133 MHz, operational system - Windows.
  • Time to set an operational mode - not more than 5 min.
  • Non-stop work duration - not less than 24 hours.
  • Registration process mode - continuos with an exposition 16 ms.
  • Working range of the environment temperature - from +15° to 135°C.

The software of the system allows: to adjust and to trim the system, to control samples reflection coefficient in the whole working range by way of diagrams in the real time, to compare a registrated spectral characteristics during the process with the characteristics of the best product (or standard). The programme also provides the express control after the operation and the registration of the reflection spectrums and the light transmission spectrums of a produced coating, to preserve, to look through, to process and to print the results of control.

 

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