Reliability Study On Multi-layer Substrates Of MCM And Thick-film Resistors

Thanks to its advantages such as small volume, light weight and good performance, Multi-chip Module (MCM) has drawn especial attention and has extensive applications in electronics, medication, spaceflight, automobile and telecommunication. Synchronously the reliability of MCM becomes one of research focuses internationally.This paper mainly studies the reliability of substrates of MCM-C including thick-film resistors, metal lines and vias for interconnection. Three types of LTCC (Low-temperature co-fired) substrates with different layers 5, 10 and 15 were designed and made. On top of the substrates locate three kinds of resistors with different resistances 10 ohm, 10K ohm and 100K ohm, and metal lines and vias are used for interconnection between layers. In the whole experiment, resistance of resistors and lines is our testing parameter. The experiment contains two sections, one is comparison experiment under extreme stresses (GEES), and the other is life-accelerated experiment with dual stresses (LAEDS). CEES Follows the method 1010A in GJB548-9, that is, samples are conducted temperature cycling experiment on temperature condition from -65 C to 175 C. While LAEDS conducts experiment under two temperatures 200 C and 230 C, each temperatures with two voltage stresses 16/60V and 12/45 V.With statistical theory this paper first carries out test of goodness of fix on life distribution, with the results that we can accept the hypothesis that the life of thick-film resistors obeys Weibull distribution. Then Best Linear Unbiased Estimation (BLUE) is used to figure out the distributional parameters, thereafter some life parameters such as average life and characteristic life can be available. From the experimental data under two different voltage stresses electric acceleration coefficient is calculated then anti-power law coefficient is figured out. From the experimental data under two different temperatures activation energy is calculated following Arrhenius law, after which life of room temperature can be extrapolated.At last, this study shows the results as follows. Life of thick-film resistors in LTCC substrates made in China obey Weibull distribution with shape parameter m=1.1549; The coefficient of anti-power law of electric stress is a =5.7143; Activation energy EI_ EH and Em of film resistors in 5-layer, 10 layer and 15-layer substrates are 0.192eV, 0.165eV and 0.114eV respectively; The resistor life in the three kinds of substrates has a ratio I2: II3: III2=:432.068: 407.088: 300.296=1.44: 1.36: 1.