EE 143 Microfabrication Technology Professor Ali Javey ajaveyeecs

EE 143 Microfabrication Technology Professor: Ali Javey ajavey@eecs. berkeley. edu 506 Cory Hall (510) 643 -7263 TAs: Sang. Hoon Lee, leesh@me. berkeley. edu Peter Matheu, peter_matheu@berkeley. edu John Wyrwas, jwyrwas@eecs. berkeley. edu Web Page: http: //www-inst. eecs. berkeley. edu/~ee 143/ EE 143 – Ali Javey Slide 0 -1

Schedule • Lectures: Tue/Thu, 3: 30 pm-5 pm • Labs (218 Cory) – only 5 of the following 6 sections will be offered: – – – M 2 -5 P, 218 CORY Tu 10 -1 P, 218 CORY W 9 -12 P, 218 CORY Th 11 -2 P, 218 CORY F 9 -12 P, 218 CORY LAB SECTIONS WILL BEGIN ON January 28 th • Office Hours: – Ali Javey (Cory Hall, 506) Wednesdays, 10 -11 am – TAs (TBD) EE 143 – Ali Javey Slide 0 -2

Reading Material • Primary Text: Introduction To Microelectronic Fabrication R. C. Jaeger Prentice Hall • Reference Texts: Semiconductor Device Fundamentals R. F. Pierret Addison Wesley Device Electronics for Integrated Circuits R. S. Muller and T. I. Kamins Wiley EE 143 – Ali Javey Slide 0 -3

– Laboratory Grading • Includes quizzes, lab work, and reports 30% – Homeworks • Assigned on Thursdays, due the following week in class • You must work on your own 10% – Tests (2 -3) • ~75 minutes each • given periodically per schedule • Open book and notes • No makeups 30% – Final Examination • Friday, Dec. 15 th, 12: 30 pm 3: 30 pm • Open book and notes • No makeups EE 143 – Ali Javey Letter grades will be assigned based approximately on the following scale: A+: 95 -100 A: 88 -95 A-: 85 -88 B+: 80 -85 B: 73 -80 B-: 68 -73 C+: 65 -68 C: 60 -65 C-: 55 -60 D: 40 -55 F: <40 30% Slide 0 -4

Course Information • Prerequisites: – EE 40/E 100 and Physics 7 B or equivalent • Course Description – EE 143 teaches the fundamentals of integrated-circuit (IC) fabrication and surface-micromachining technology, giving the student a basic understanding of IC and micromachining processes and the effect of processing choices on device performance. Students learn to use process simulation tools and also fabricate and characterize devices in the laboratory. This lecture part will cover the processing techniques and design methodologies of microfabrication. We will discuss the process modules: lithography, thermal oxidation, diffusion, ion implantation, etching, thin-film deposition, epitaxy, metallization. The second part of the course will cover process simulation, layout design rules, MOS, IC, and MEMS process integration. The laboratory part of the course will provide students opportunities to have hands-on experience to fabricate and characterize a NMOS chip with simple MEMS components. EE 143 – Ali Javey Slide 0 -5

Course Schedule Introduction to Materials and Processing (1 -2 weeks) Photolithography (1 week) Etching (1 week) Oxidation (1 week) Deposition (1 week) Diffusion (1 week) Ion Implantation (1 week) Metallization/CMP (1 week) Simulation/Layout (1 week) Process Integration (1 week) Introduction to Devices (2 weeks) Nanolithography and Nanofabrication (1 week) EE 143 – Ali Javey Slide 0 -6

Laboratory Information • We do our best to limit lab size to 12 people; as a result, your telebears enrollment is not a guarantee of being assigned to a lab. • You MUST send an email to Professor Javey (ajavey@eecs. berkeley. edu) by Thursday 8 pm including the following information: – 1) Full Name – 2) Major – 3) Year (Jr. , Sr. , Grad student, etc. ) 4) Rank list of preferred lab sections in descending order of preference (i. e. , 1 st choice, 2 nd choice…) – 5) List of any lab sections that you CANNOT attend • Failure to send an email may result in you being dropped from the course, even if you are registered on telebears. • Final lab assignment will be sent to you via email. PLEASE ENSURE THAT YOUR EMAIL ADDRESS ON TELEBEARS IS CORRECT, SINCE THIS WILL BE USED FOR OFFICIAL CORRESPONDENCE!!! EE 143 – Ali Javey Slide 0 -7

Lab Safety Week of 1/28 • Mandatory Lab attendance required • You will have a lab orientation session, and will have to pass a safety quiz before you are officially enrolled in this course. • You MUST attend the lab session to which you are assigned. EE 143 – Ali Javey Slide 0 -8

Course Structure – Lab and Lecture • You learn theories in class; you practice them in lab • You are going to make: – resistors, diodes, MOS-cap – bipolar transistor, MOS-transistor, … – some MEMS structures, like bimorphs, … • By the end of the semester, you should have learnt – basic lab techniques – how to operate some fabrication equipment – how to characterize the devices you made EE 143 – Ali Javey Slide 0 -9

The EE 143 Chip EE 143 – Ali Javey Slide 0 -10

Lab Cleanliness • only enter the clean room fully gowned – hair net + lab coat + glove + shoe net + safety goggles • do NOT touch chemicals / equipment with bare hands • always handle wafers with tweezers and trays (unless told otherwise) • wash hands before and after entering the lab (why? ? ) – before: so as not to contaminate wafers or equipment – after: avoid chemicals being indigested • 3 rd week, GSIs will demonstrate how to clean masks • 4 th week, GSIs will demonstrate how to piranhaclean wafers EE 143 – Ali Javey Slide 0 -11

Lab Safety • do NOT enter the lab when GSI aren’t present • know all the emergency exits (ask the GSIs to show you) • know where to find the MSDS – under the whiteboard in characterization room • know where to find the closet water sources, shower, eye wash • ask whenever not clear • do NOT try things out without permission • NO eating, drinking, playing, etc. inside the lab • Things in the lab can be dangerous if not carefully handled. Be sure to respect the chemicals. EE 143 – Ali Javey Slide 0 -12

Chemical Handling • wear protective gear when handling corrosive chemicals – face shield, chemical apron, chemical gloves, respirator if necessary • • check glove for holes check p. H of unknown spillage, label everything corrosive chemicals: H 2 SO 4, HF, aluminum etch, TMAH wash and rinse the exposed body parts with water for > 15 mins • add acids to water, not the other way around • handle wet chemicals only at sinks, acid on right, others on left side EE 143 – Ali Javey Slide 0 -13

Chemical Handling (cont’d) • HF: – be very careful – HF will penetrate your body and attack your skeletal system; once you feel it, it is already eating your bones!!! – apply calcium gluconate if exposure is suspected – use only plastic beakers for HF (why? ? ) • H 2 SO 4: – – very painful, severely burns add H 2 O 2 to H 2 SO 4 to prepare piranha do not carry the beaker around after mixing (HOT!!) use only glass beakers for piranha (why? ? ) • Chemicals used in the lab are often harmful. Don’t breathe and avoid exposure if possible. • Use teflon-ware when handling wafers in acids. Be careful, those teflon tweezers do not hold the wafers very well!! EE 143 – Ali Javey Slide 0 -14

Chemical Disposal • organic chemicals are discarded in designated containers • NOTE: in this lab, photoresist (PR) is also dumped down the drain. • do NOT mix organic wastes with acids (why? ? ) – can cause fire or even explosion • do NOT mix acids and bases • EE 143 – Ali Javey Slide 0 -15

Lab Floor Plan Note: Not drawn to scale EE 143 – Ali Javey Slide 0 -16

EE 143 Overview • Microfabrication Principles for IC and MEMS • Hands-on Fabrication and Testing of IC and MEMS Devices EE 143 – Ali Javey Slide 0 -17

Fabricated Structures • Using a series of planar processing steps, it is possible to create sophisticated 3 D electrical and mechanical structures. EE 143 – Ali Javey Slide 0 -18

Electrical Functionality / Characterization • The resulting structures may be characterization electrically or mechanically 17 -stage Ring Oscillator EE 143 – Ali Javey Slide 0 -19

MEMS Actuators Gear Speed Reduction Unit Responsive. EE 143 Drug Delivery Valve – Ali Javey Movable Mirror Turbine engine Slide 0 -20

Introduction to Si Processing EE 143 in one day

Silicon Device Fabrication Technology Over 1019 transistors (or 1, 000, 000 for every person in the world) are manufactured every year. Variations of this versatile technology are used for flat-panel displays, micro-electro-mechanical systems (MEMS), and even DNA chips for DNA screening. . .

Terminology SSI (Small Scale Integration) – few transistors MSI (Medium Scale Integration) – hundreds LSI (Large Scale Integration) - thousands VLSI (Very Large Scale Integration) - millions ULSI (Ultra Large Scale Integration)

Foundry (Fab) • Foundry (also called a fab for fabrication plant) is used to refer to a factory where devices like integrated circuits are manufactured. The central part of a fab is a cleanroom. • Note the difference between a fab and a lab.

Cleanroom Standards Federal Standard Class Limits MEASURED PARTICLE SIZE (MICROMETERS) CLASS 0. 1 0. 2 0. 3 0. 5 5. 0 1 35 7. 5 3 1 NA 10 350 75 30 10 NA 100 NA 750 300 100 NA 1, 000 NA NA NA 1, 000 7 10, 000 NA NA NA 10, 000 70 100, 000 NA NA NA 100, 000 700 Why do we need cleanrooms?

Introduction to Device Fabrication Oxidation Lithography & Etching Ion Implantation Annealing & Diffusion Deposition

Oxidation of Silicon Dry Oxidation : Wet Oxidation : Si + O 2 Si. O 2 Thin oxide Si +2 H 2 O Si. O 2 + 2 H 2 Thick oxide

Oxidation of Silicon

Lithography Development Resist Coating Positive resist Photoresist Oxide Si (a) Deep Ultraviolet Light Optical Lens system Si Si (c) Photomask with opaque and clear patterns Si Exposure Negative resist (b) (d) Si Etching and Resist Strip

Pattern Transfer–Etching wet etch Isotropic etching dry etch Anisotropic etching

Module: Ion Implantation Ion Energy ~1 ke. V to 200 ke. V EE 143 – Ali Javey Slide 0 -31

What is process integration? • Sequential use of a series of simple process steps or “modules” to create complex structures Si wafer Processing Steps EE 143 – Ali Javey Slide 0 -32

The EE 143 Lab Process (part I) EE 143 – Ali Javey Slide 0 -33

The EE 143 Lab Process (Part II) EE 143 – Ali Javey Slide 0 -34