Reliability and Failure of Electronic Materials and Devices 2nd. Edition by Milton Ohring, Lucian Kasprzak | 9780120885749 | 120885743 | Holooly

Electronic Devices and Circuits

Reliability and Failure of Electronic Materials and Devices

19 SOLVED PROBLEMS

Question: 4.3

A collection of 60 laser diodes were tested, and 7 failures occurred after 1000 h. The lifetimes obtained are tabulated below. 1. Plot the results in both Weibull and lognormal fashion. 2. What is the MTTF for each? 3. For the lognormal plot, what is the value of σ? 4. For the Weibull plot, what ...

Verified Answer:

First,

F(t_{i})

is calculated for n...

Question: 7.1

After introduction of 1.7 ppm of Cl2 into an 85°C/80% RH ambient, the corrosion leakage current across metal stripes on a ceramic substrate increased. If the moisture layer is 100 nm thick, what is the electrolyte sheet resistance? ...

Verified Answer:

Chlorine dissolves in water through the reaction [...

Question: 4.4

Consider a 50-pin module such that the probability of failure upon inserting it into a mating connector is 1.8 × 10^-3 % per pin. What is the probability of failure of the module? ...

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In this problem the module is the system (s), and ...

Question: 8.1

Consider a ceramic package where the solder glass used has the following properties; E(g) = 0.7 × 10^6 kg/cm², v(g) = 0.27, α(g) = 6.8 × 10^-6 °C^-1. Similarly, for the alumina ceramic, E(c) = 3.5 × 10^6 kg/cm², v(c) = 0.25, α(c) = 7.2 × 10^-6 °C^-1. If the seal processing temperature is 450°C, ...

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It is assumed that all stresses are relieved at 45...

Question: 5.1

Consider the contact structure of Figure 5.7(c) consisting of a pure Al film of indicated geometry over Si. Calculate the depth (y) of Si depletion in the wafer during a processing heat treatment of 1 h at 450°C, where the solubility (S) of Si in Al is 0.5 wt%. The respective densities for Si and ...

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The amount of Si needed to saturate the metal cont...

Question: 9.2

In flip-chip interconnections using 95 Pb-5 Sn solder, suppose that stresses encountered in service fluctuate between σ/G = 7 × 10^-4 and 1 × 10^-3 at temperatures between 25 and 35 °C. A measure of contact degradation is taken as the ratio of creep strains at the two stress levels. What is ...

Verified Answer:

We refer to the high stress/temperature state as 2...

Question: 4.1

Suppose that a population of 525,477 solid-state devices is burned in at elevated temperature, and the number of failed devices are weeded out as a function of time is recorded in the following table. Determine the failure rates, λ(t), at the indicated times. ...

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Results of the calculations are tabulated. Tim...

Question: 4.6

Suppose that ICs are used in a critical application at 40°C. The manufacturer selects a sample population of 1000 chips, ages them at 150°C for 2 years (ta = 1.75 × 10^4 h) and no failures are observed. Typical data for other similar products suggest that the activation energy for failure is 0.4 eV ...

Verified Answer:

First the AF is evaluated from Eqn (4.36):

...

Question: 6.1

A pulse of 4500 V is discharged from a person into a pen junction. The junction area is 5 × 10^-7 cm² and the resistance is 20Ω . Assume that the voltage across the device is negligible compared with that of the ESD pulse. a. Over what time span does the discharge occur? b. What is the maximum ...

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a. For the human body model the time constant is [...

Question: 9.4

Accelerated temperature cycling of solder joints on a 256 pin quad flat package (QFP) was carried out at a frequency of 1 cycle/45 min over the range -40 to 125 °C. The Weibull cumulative failure distribution was found to be of the form Fs(t) = 1 – exp[-(t/42,900)^1.27], where t is the time in ...

Verified Answer:

1. Substituting in Eqn (9.38),

AF=\frac{N(u...

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