O cristal monitor de quartzo é um sistema essencial para medição e controlo com base em cristal de quartzo.

 

O cristal permite deposições de película fina precisas e repetíveis.

 

A microbalança de cristal de quartzo (QCMs) é um dispositivo microelectrónico utilizado em câmaras de deposição a vácuo para medir a espessura de película fina em substratos. Isto é feito utilizando a resposta de frequência fornecida pelo cristal de quartzo durante o processo de revestimento. Esta mudança de frequência pode ser associada à quantidade de material de revestimento sobre a superfície do cristal.

Os cristais de quartzo apresentam espessura ao nível de Ångström (1 Angstrom é equivalente a 0,00000000393701 Polegadas ou 0,0000001 Milímetros). O seu nível de precisão e precisão é significativo porque desvios de espessura tão pequenos quanto 10 Angstroms podem ter um grande efeito no desempenho do produto.

A implicação deste processo no sistema de controlo e a sua limitação é um passo importante para o desenvolvimento de produtos inovadores e novos. A importância dos sensores de cristal de quartzo tem vindo a aumentar nos últimos vinte anos, uma vez que os dispositivos ópticos, eléctricos e magnéticos mais avançados exigem um sensor capaz de processar as medições correctas.

Algumas das indústrias que utilizam este processo nos seus processos de produção: óptica, semicondutor, célula solar, e visor de película fina (OLED).

Obtenha uma vida mais longa do cristal do seu monitor de quartzo por selecção do eléctrodo apropriado.

 

  • 6MHz Quartz crystal sensors compatible with INFICON monitor, cotroller and microbalance.
    • Size: 14 mm (0.550 in.)
    • Frequency: 6 MHz
  • 5MHz Quartz crystal also available.
    • Size: 12.4 mm (0.489 in.)
    • Frequency: 5 MHz

Electrode Chart Selection

Electrode MaterialApplication TypeElectrode Chart SelectionMain Property
GoldStandardInfiniteMost common, adapted for most applications
SilverSputtering TypeDepends on oxidation and exposure to sulfur content in air (tarnishing effect)Highest thermal conductance. Adapted when better heat transfer to cooled sensor body is needed.
AlloyHigh Stress Coatings, Optical films, high stress semiconductor materialsShorter than gold, two times more than Silver, with time alloy oxidizeHigher Activity values compared to Gold and Silver

Check the quartz thin-film monitor equipment here.

About Quartz Crystal microbalance

QCM (quartz crystal microbalance) sensors measure the mass variation per unit area by measuring the changes in the resonator frequency of a quartz crystal using its piezoelectric properties. Frequency changes linearly with the mass (or thickness). Quartz crystal monitoring systems are an essential component of the thin film deposition vacuum chambers, usually used in mass production.

quartz crystal monitor

It’s very important to control the temperature since the resonance frequency can change a lot with the temperature too. There are different types of crystals depending on its tolerance with the temperature.

Usually, work at the Ångström level (Order of 10-10). Little thickness deviations such as 10 or fewer Ångströms can have a major effect on the product performance. QCM sensor measurements have been improving more and more in the past years. Nowadays advanced optical, electrical, and magnetic devices require a process sensor capable of measuring layer thicknesses with 1 Ångstrom resolution reliably.

 

How does a typical QCM system look?

Inside the vacuum chamber, the sensor is placed near the substrate to measure the thickness of the film. It’s important to know its operating frequency range and the electrode quality of this crystal. The vacuum chamber must have a tem perature controlled housing with the function of regulating the temperature of the sensor and its mechanical integrity.

Outside the chamber, an electric monitor creates a current which forces the crystal into vibration and tracks this frequency over time. It’s really important that this monitor can track accurately the crystal frequency changes and temperature characteristics. An internal microprocessor can convert this frequency changes in time to the actual thickness of the film.

 

Principal characteristics of the quartz crystals:

The crystal can have different electrode shape depending on the model system you are purchasing.

Physical Specifications of the crystal:

  • Material: Pure Silicon Dioxide monocrystal.
  • Dimensions: 0.550” +. 000/.002” OD
  • Contour: 2.5 – 3.0 diopter (212 – 177 mm radius of curvature) plano-convex
  • Finish: 7 microns rms roughness plano and contour sides
  • No chips, scratches or etch marks within a 13.95 mm diameter clear aperture

Electrical Specifications of the crystal:

  • Available Frequencies: 5 and 6 MHz, fundamental series resonance
  • Resistance: <10-15 Ohms
  • Contact Resistance: <10 Ohms edge to edge on pattern side

We also offer Physical vapor deposition (PVD) products and solutions, click here to access our page.