1. Reliability Laboratory Presentation on Setting up Reliability Laboratory Presented by Dr. G.H. Massiha Department of Industrial Technology University of Louisiana, Lafayette

2. Topics Need for setting up Reliability Laboratory Reliability issues in Metal thin Films. Reliability Problems. Electromigration Measurement Techniques. Excess Noise Measurement. 1/f Noise Phenomenon. Presence of 1/f Noise. Measurement System And Technique. Experimental Set-up Diagrams of the samples used. Results Concluding Remarks

3. Need for setting up Reliability Laboratory One of the research lab in Department of Industrial Technology, University of Louisiana at Lafayette provides facility for students to study reliability issues in metal thin films. Students will learn new techniques to measure excess noise in the metal thin film. This hands on experience will make students well prepared to handle challenges in the various research labs, on joining industry. Website at: http://www.ucs.louisiana.edu/~ghm2469

4. Reliability issues in Metal Thin films Metal Thin Films should maintain Structural integrity. In Metal thin films structures chemical reaction or inter diffusion appears in small scale at room temperature. Tighter constraints are placed on film material and dimensions.

5. Reliability Problems The decrease in the thin film dimension has caused a rise in the current density. The failure mechanisms encountered in VLSI, metallization defects form the 20 –30%. Metallization Defects: Electromigration – Most prominent device failure mode. Aluminum Micro-cracks Contact Alloying Problems Bonding Problems

6. SEM Picture of Damaged Al Film

7. Electromigration Measurement Techniques Measurement of mass accumulation and Depletion. Needs special Design samples, expensive experiment setup. The Median Time Failure Measurement(MTF) Needs large number of identically and fabricated samples. Resistance Measurement It is difficult to assume that the electromigration is the only source of resistance change. – Also, a long period of test time is needed and the test samples usually are not reusable for repeating electro- migration tests.

8. Excess Noise Measurement Have close links to the electromigration damage in the thin films. Magnitude of excess noise is very sensitive to its electromigration damage. Short period of time needed for noise measurements. Non-destructive nature. Ideal tool for studying electromigration in thin films.

9. 1/f Noise Phenomenon 1/f 0 white noise, shows a fluctuation in which the power changes at random, irrespective of wave frequency. The 1/f 2 Brownian noise, the bottom curve, shows waves which change in very strict conformity with a certain fluctuation pattern. The 1/f, the middle line, indicates a pattern in which the power change is inversely proportional to the frequency. The 1/f noise is less random then White Noise and more random then Brownian noise

10. Presence of 1/f Noise It appears in widely different systems such as radioactive decay, chemical systems, biology, fluid dynamics, astronomy, electronic devices, optical systems, network traffic and economics. Classical music and 1/f noise. -- Frequency is inversely proportional to the power, a relationship which creates 1/f fluctuations. The constant, rusty noise of a TV after broadcasting ends is displeasing. On the contrary, wave patterns which are most soothing conform to the 1/f fluctuation. The sounds created by classical music following a 1/f fluctuation patterns are especially soothing to our ears.

11. Measurement system and Techniques An oscilloscope can be used to see and measure a voltage across a resistor when direct current is passed through the conductor. Using a very fine lens to look at the voltage configuration on the oscilloscope screen, one can see that the voltage fluctuates with time.

12. Experimental setup SR785-100 kHz Dual channel Dynamic Signal Analyzer. EG&G Ultra Low-Noise Voltage Preamplifier. SR715 LCR meter. DC Power Supply MultiMeter. Biasing Circuit Thermocouple

13. SEM Picture of The Sample

14. Layout of the Sample Used 2 set of three different thin film resistances R1 = 75.7  R2 = 63.12  R3 = 39.96  R1 R2 R3

15. Resistance variation with Temperature

16. A Typical One over f Noise 1/f Noise Spectrum from 3 to 300 Hz.

17. Concluding Remarks Noise measurement is a quick technique of understanding characteristics of interconnects and provides with information about reliability. Students learn how to use Spectrum Analyzer to capture and analyze signals generated by the change in the metal thin film resistance while the film is biased and is under stress. In addition Students learn the capability and usage of low noise amplifier, thermocouple, and LCR meter. Furthermore, students learn to design and build biasing and stressing circuits. In conclusion students working in this research laboratory would write a technical paper to present the results obtained in various experiments performed. We hope students become prepared to the challenges of working in various research laboratories when they join the industry.

18. Contributed By Kuldeep S. Rawat Graduate Student Center for Advanced Computer Studies Edie Lau Undergraduate Student Industrial Technology University of Louisiana, Lafayette This study is sponsored by the State of Louisiana Board of Regent Contract No. LEQSF(1999-02)-RD-A-54 Contributed By Kuldeep S. Rawat Graduate Student Center for Advanced Computer Studies Edie Lau Undergraduate Student Industrial Technology University of Louisiana, Lafayette This study is sponsored by the State of Louisiana Board of Regent Contract No. LEQSF(1999-02)-RD-A-54