JPS5697809A - Method and device for measuring thickness of dielectric layer with sandwiched conductive layer - Google Patents

Abstract

PURPOSE: To measure the thickness of a dielectric layer rapidly without destruction by measuring electric static capacity on a sheet top surface side and reverse surface side across a conductive layer.

CONSTITUTION: The surface of the 2nd dielectric layer 3 of sheet SHT consisting of the 1st dielectric layer 1, conductive layer 2 and the 2nd dielectric layer 3 is brought into close contact with the smooth surface of measurement table 5. The electrostatic capacity (the 1st electrostatic capacity) between conductive layer 2 and electrode 4 is expressed by equation I, where the layer thickness of the 1st dielectric layer 1, its dielectric constant, the layer thickness of conductive layer 2, the layer thickness of the 2nd dielectric layer 3, its dielectric constant, the area of measurement electrode 4, the distance between it and the smooth surface, and the dielectric constant under a vacuum are denoted as d₁, ε₁, d₂, d₃, ε₃, S, d₀, and ε₀ respectively and conductive layer 2 is grounded. Similarly, the 2nd electrostatic capacity C₂ is expressed by equation II when the surface of the 1st dielectric layer 1 is brought into close contact with the smooth surface of measurement table 5. Therefore, thickness d₁ and d₃ of dielectric layers 1 and 2 can be calculated by calculating equations III and IV by using said actually-measured values C₁ and C₂.

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