Northwestern Mechanical Engineering 451: Micromachining

Catalog description  Fundamental fabrication issues for microscale components used in MEMS/Nanotechnology. Understand and designing microfabrication processes based on photolithography and deposition/etching steps.  Prerequisite: Senior standing or higher

Who takes it Tech or other science major graduate students who plan their research based on micro/nano systems approaches. Those who want to gain broad knowledge about the new micro/nano technology trends.

What it's about  Micro Electro Mechanical Systems (MEMS) has demonstrated powerful capabilities in many fields of engineering and science. MEMS-based commercial products are already in the market, replacing existing technology, or creating new possibilities. This technology is firmly based on a unique manufacturing paradigm, micromachining. Micromachining is a core technology that enables the MEMS and related new approaches in engineering and science. This course will cover the fundamental fabrication and theoretical issues of the micromachining critical in micro/nano systems applications.

Textbook Foundations of MEMS, by Chang Liu.  Introduction to Microelectronics Fabrication, R.C. Yaeger. 

Week 1: Overview of Microelectronics and MEMS Technology. Detailed analysis of MEMS products: DLP mirror display, SmartPhone gyroscopes, accelerometers. * Show'n'tell slides 

Week 2: Overview of cleanroom and foundry operations. Basic fabrication knowledge: Lithography, oxidation, chemical vapor deposition, dry etching. MEMS intro.  Litho+Metal 

Week 3: Basic fabrication knowledge: wet etching, deep reactive ion etching, wafer bonding oxidation film deposition etching doping interconnects 

Week 4: MEMS processing: Bulk micromachining. Surface micromachining. Sacrificial layer etching.  Surface micromachining Bulk machining  Table of commonly encountered MEMS materials Table of commonly used processing methods Table of reaction between the common materials and processes

Week 5: Circuit fundamentals. Basic MOS circuit design and fabrication. Process-Mat-Design Synthesis. Mask layout. CMOS BJT Integration  

Week 6: Novel fabrication techniques.  NEMS. MEMS/Circuit Integration. Wafer/chip packaging and encapsulation. MEMS vacuum packaging and encapsulation. process magic  

Week 7: Case studies: how to make cantilevers with bells and whistles on them. 

Week 8: Case studies: accelerometers and motion sensors for consumer electronics and automotive applications. STMicroelectronics, InvenSense, Analog Devices. History. Cross comparison.

Week 9: Case studies: microfluidic devices for biomedical applications, bioMEMS devices 

Week 10: Case studies: pressure sensors and acoustic sensors.  The business of microfabrication and MEMS (patents). Final Presentations on the last two lectures. (Final presentation will also be held in the finals week).

Finals project:

Form 1-3 people teams (must cross at least two department if more than one).  Choose from the following options:
Option 1: Conduct a survey (technical literature, patent, business news) on a material or fabrication process related to fabrication and packaging of integrated electronics, preferrably a new, emerging technology. 
(Suggestions of processes: through silicon via, stack packaging, three dimensional printing, stealth dicing, ultra lithography, Parylene, deep reactive ion etching, silicon germanium, Bosch process, ICP RIE, chip packaging trends. SOI transistor)
(Suggestions for materials: ultra capacitor, gate oxide technology, hafnium oxide, large wafer, etc)

Hint: Find out about principles, background, intellectual properties, pros and cons, competitors, benefits to business (e.g., cost saving).

Option 2: Conduct a survey of a class of devices or products (not process or materials).  Preferrablly study a family of competing devices for a given application or service. Explore the current technical and commercial landscape pertaining to this product. If possible, identify a possible revolutionary fabrication process, material, or design that would provide a game changer or improvement. 
(Suggestions of device classes: magnetic field sensors, inertial measurement units, large screen TV monitors, photovoltaic panel, rechargable batteries)
(Suggestions of applications: projection display, ink jet printing, pico projector, etc)
(Suggestions for companies: motion sensor companies (Analog Devices, InvenSense, STMicroelectronics, etc), IMU companies, acoustic sensor companies, pressure sensor companies, flow sensor cmopanies, magnetic field sensor companies, solar photovoltaic companies, processing equipment manufacturers).

Report and presentation

Prepare a slide show (must be 20 sliders or fewer) to summarize your survey results.  For option 1 type, must present comprehensive and detailed technical analysis. All major claims must be backed by evidence or analysis.  The survey must cover respectable depth and breadth. For option 2 type, must present comprehensive review of existing state of the art honestly before proceeding to identify key improvement ideas.

A group presentation will be given to the entire class.  Each presentation, irrespective or group size and topic, must be less than 18 min, with 2 min allocated to questioning.

Each group should email the ppt file to the instructor (email or via file transfer such as yousendit) at least 2 hours prior to the final presentation. Each group should also prepare a second option (own computer or flash drive) to make sure the talk will run smoothly. Try avoid embedding animation and movies in the ppt file.  The submitted file should be in .ppt format, not .pptx. A PDF version is also requested to be emailed to the instructor to make sure the appearance won't chance across systems. 

A technical dossier (printed, stapled or otherwise securely assembled) should be delivered to the instructor prior to the presentation. The dossier should contain the following:
1. Printout of all PPT pages (3 slides per page style);
2. Up to five key references or papers.

Criteria for evaluating the presentation:
1. A presentation must teach the class well about the topic you studied;
2. A presentation should not be a simple stacking of facts. It should provide insight and analysis;
3. A presentation should have both technical depth (model, pros and cons, limitations) and breadth (bigger picture, competition, technology trends, technical and business needs).

Advise: be curious and dig deep.  Don't be afraid to dig up dirts (technical or business) that will "ruin" the good news.  If you don't finish with a good news in the end, it is alright.  What is not alright, is for people to not spend the time, not be honest and logical, and assume too many things without asking critical questions. WHAT MATTERS IS THAT you understand what you talk about.

Grading will be based on the quality of your research and your talk. Five minutes into your talk, it will become apparent to everyone whether you did your research or not. At finish, I suspect the degree of your accomplishment will be plainly simple for everyone to judge. The only way for you to do well, is to spend time. For example, you may want to Google some terms, go from page 1 to page 100 of the search results, and follow each link in the search. And then keep going. You should feel your efforts is not a linear effort, but an exponentially growing effort. This is what exhaustively researching a topic should feel like.

Certainly, make sure you work on a topic you are interested in deeply. Otherwise you will miss at least 90% of the fun.