EEC146B - Advanced Integrated Circuits Fabrication

3 units - Winter Quarter

Lecture: 2 hours

Laboratory: 3 hours

Prerequisites: EEC146A

Grading: Letter

Catalog Description: Fabrication processes for CMOS VLSI. Laboratory projects examine deposition of thin films, ion implantation, process simulation, anisotropic plasma etching, sputter metallization, and C-V analysis. Topics include isolation, projection alignment, epilayer growth, thin gate oxidation, and rapid thermal annealing.

Relationship to Outcomes:
Students who have successfully completed this course should have achieved:

Course Outcomes ABET Outcomes
An ability to apply knowledge of mathematics, science, and engineering A
An ability to design and conduct experiments, as well as to analyze and interpret data B
An ability to function on multidisciplinary teams D
An ability to identify, formulate, and solve engineering problems E

Expanded Course Description

  1. VLSI Processes
    1. Low-pressure chemical vapor deposition (LPCVD)
    2. Silicon, silicon dioxide, and silicon nitride thin films
    3. Device isolation by local isolation (LOCOS) and trench
    4. Epitaxial layer growth, film thickness optimization
    5. Vacuum systems: selection, design, and application
    6. Glow discharge processing
    7. Isotropic plasma etching, reactive ion etching (RIE), ion milling
    8. Ion implantation and graded impurity profiles
    9. Projection alignment and stepping
    10. Submicron structure processing using electron beam lithography
    11. Mid-UV proximity alignment
    12. Mask making for different aligner sources
    13. Thin gate dielectric growth
    14. Rapid thermal annealing. criteria for selecting run times
    15. Sputter deposition of metals and silicide formation
    16. Factors pertaining to formulating new processes
  2. Process Characterization Techniques
    1. Van der Pauw structures, Hall devices, and data interpretation techniques
    2. C-V and C-t analysis of MIS diodes
    3. Process simulation using SUPREM, energy and range selection criteria
    4. Step profilometry
    5. Light and dark field and interference-contrast optical microscopy
    6. Spreading resistance measurement
    7. Mass spectrometry and RGA end point detection
    8. Chemical defect etching
  3. Reliability Issues
    1. Electromigration elimination
    2. Hot carrier degradation and practical solutions
    3. Bird's beak
    4. Alpha-hit protection
    5. Latchup
    6. Body effect
    7. Punch-through
    8. Practical methods for eliminating failure mechanisms

Textbook: S. Ghandi, VLSI Fabrication Principles, Wiley.

Reference: S.Wolf and R. Tauber, Silicon Processing, Wiley.

Computer Use:
Three laboratory projects and two problem sets require the use of turn-key process simulation software, SUPREM-III. This operates on UNIX-based computers. Students need to generate an input file with the text editor and plot/print program results using various output devices.

Laboratory Projects:
Ten weekly three hour laboratory projects, corresponding to major technologies used in modern CMOS fabrication. Any fabrication procedures used in any given week's lab correspond to the technology being presented in the lectures that week, thereby providing immediate hands-on experience. A major project in design, fabrication and testing of MOS C­V and C-t test devices extends over several lab sessions. Design by using CAD software and testing of devices fabricated according to these designs is a key issue.

Engineering Design Statement:
Students are required to specify appropriate desirable operating performance, with justification, of the final device and design the process used to obtain that performance. Problems in the class are open-ended with different approaches being valid according to initial conditions of the IC and the technology chosen. Students learn to design a process to optimize performance and yield, and minimize complexity and parasitic effects. Students are required to compare theory with experimental results and to justify the differences. They are furthermore required to predict where digression from theory is likely to occur and account for this in setting fabrication operating parameters. Several issues of design are beyond simple analysis and therefore require CAD tools. Students must make judgements in setting process variables within the practical confines of the fabrication equipment they will be using.

Professional Compoenent: Engineering Depth, Laboratory
Engineering Science: 1 unit
Engineering Design: 2 units