Testing method for water vapor penetration rate of thin film

Abstract

The invention discloses a testing method for the water vapor penetration rate of a thin film. The testing method comprises the following steps: S1, evaporating a calcium thin film layer on a substrate; S2, depositing a packaging thin film layer on the substrate through an atomic layer deposition layer under protective gas, enabling the calcium thin film layer to be covered with the packaging thin film layer to obtain a thin film device to be measured; and S3, testing the thin film device to be measured obtain in the step S2 by adopting a Kelvin four-probe method, obtaining a time-varying conductivity curve of the calcium thin film layer in the thin film device to be measured, and extracting the slope of a linear part of the curve: d(1 / R) / dt, and substituting into a next formula as shown in the specification to obtain the water vapor penetration rate of the thin film eta WVTR, wherein in the formula, n is water vapor penetration characteristic coefficient at the temperature of 25 DEG C, M(H2O) is the molar mass of water, M(Ca) is the molar mass of calcium, delta is calcium specific resistance, rho is calcium density, L is the length of the calcium thin film layer, and W is the width of the calcium thin film layer. The test precision can reach 1 * 10<-6> g * m<-2> * d<-1>, and the test method has the advantages of being quick, simple, high in accuracy and the like.

Description

technical field [0001] The invention relates to a method for testing the water vapor transmission rate of a thin film, in particular to a method for testing the water vapor transmission rate of a thin film used in an OLED display device. Background technique [0002] In the development of OLED (Organic Light-Emitting Diode, Organic Light-Emitting Diode) technology, high-reliability packaging technology has become one of the key issues that need to be solved urgently. With the development of OLED display lighting technology in the direction of flexibility, large size, and thinness, thin-film packaging has become the most promising emerging packaging technology. [0003] Film water vapor transmission rate (Water vapor transmission rate, WVTR) is the most important technical parameter for evaluating thin film packaging, and the high-precision water vapor transmission rate test method is the basis for studying the performance of packaging films. At present, the methods for test...

AI Technical Summary

Problems solved by technology

The measurement accuracy of the radioisotope tracer method is 2×10 － 7 g·m －2 d －1 , this method is expensive to test, and the radioactive substances used are dangerous to a certain extent. The requirements for equipment and laboratory conditions are relatively strict, and at the same time, many experimental parameters are involved, which are difficult to control.

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