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EE143 Microfabrication Technology

Professor: Ali Javeyajavey@eecs.berkeley.edu506 Cory Hall(510) 643-7263

TAs: SangHoon Lee, leesh@me.berkeley.eduPeter Matheu, peter_matheu@berkeley.eduJohn Wyrwas, jwyrwas@eecs.berkeley.edu

Web Page: http://www-inst.eecs.berkeley.edu/~ee143/

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Schedule• Lectures: Tue/Thu, 3:30pm-5pm• Labs (218 Cory) – only 5 of the following 6 sections will be

offered:– M 2-5P, 218 CORY– Tu 10-1P, 218 CORY– W 9-12P, 218 CORY– Th 11-2P, 218 CORY– F 9-12P, 218 CORY

LAB SECTIONS WILL BEGIN ON January 28th• Office Hours:

– Ali Javey (Cory Hall, 506)Wednesdays, 10-11 am

– TAs (TBD)

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Reading Material• Primary Text:

Introduction To Microelectronic FabricationR. C. JaegerPrentice Hall

• Reference Texts:Semiconductor Device FundamentalsR. F. PierretAddison Wesley

Device Electronics for Integrated CircuitsR. S. Muller and T. I. KaminsWiley

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Grading– Laboratory

• Includes quizzes, lab work, and reports

– Homeworks• Assigned on Thursdays, due the following week in class

• You must work on your own– Tests (2-3)

• ~75 minutes each• given periodically per schedule• Open book and notes• No makeups

– Final Examination• Friday, Dec. 15th, 12:30pm- 3:30pm

• Open book and notes• No makeups

30%

30%

Letter grades will be assigned based approximately on the following scale:

A+: 95-100A: 88-95A-: 85-88B+: 80-85 B: 73-80 B-: 68-73C+: 65-68 C: 60-65 C-: 55-60D: 40-55 F: <40

30%

10%

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Course Information

• Prerequisites:– EE40/E100 and Physics 7B or equivalent

• Course Description– EE143 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.

Course Schedule

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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)

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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 8pm 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., 1st

choice, 2nd 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!!!

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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.

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Course Structure – Lab and Lecture• You learn the 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

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The EE143 Chip

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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

• 3rd week, GSIs will demonstrate how to clean masks

• 4th week, GSIs will demonstrate how to piranha- clean wafers

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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.

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Chemical Handling• wear protective gear when handling corrosive chemicals

– face shield, chemical apron, chemical gloves, respirator if necessary

• check glove for holes• check pH of unknown spillage, label everything• corrosive chemicals: H2SO4, HF, aluminum etch, TMAH• wash and rinse the exposed body parts with water for >

15mins• add acids to water, not the other way around• handle wet chemicals only at sinks, acid on right, others on

left side

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Chemical Handling (cont’d)• HF:

– be very 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??)

• H2SO4:– very painful, severely burns– add H2O2 to H2SO4 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!!

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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•

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Note: Not drawn to scale

Lab Floor Plan

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• Microfabrication Principles for IC and MEMS• Hands-on Fabrication and Testing of IC and MEMS Devices

EE143 Overview

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Fabricated Structures• Using a series of planar processing steps, it is possible to

create sophisticated 3D electrical and mechanical structures.

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17-stage Ring Oscillator

Electrical Functionality / Characterization• The resulting structures may be characterization

electrically or mechanically

EE143 – Ali Javey Slide 0-20Responsive Drug Delivery Valve

Gear Speed Reduction Unit Movable Mirror

Turbine engine

MEMS ActuatorsMEMS Actuators

Introduction to Si Processing EE143 in one day

Silicon Device Fabrication Technology

Over 1019 transistors (or 1,000,000,000 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 transistorsMSI (Medium Scale Integration) – hundreds

LSI (Large Scale Integration) - thousandsVLSI (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

CLASSMEASURED PARTICLE SIZE (MICROMETERS)

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 SiliconSi + O2 →

SiO2

Si +2H2 O → SiO2 + 2H2

Dry Oxidation :

Wet Oxidation :

Thin oxide

Thick oxide

Si Wafers

O2 N2

H2O or TCE(trichloroethylene)

Quartz tube

Resistance-heated furnace

Flowcontroller

Oxidation of Silicon

Lithography

Resist Coating

Exposure

Development

Etching and Resist Strip

Photoresist

OxideSi(a)

OpticalLens system

Deep Ultraviolet Light

Photomask withopaque and

clear patterns

Si Si

SiSi

Positive resist Negative resist

(c)

(d)(b)

Pattern Transfer–EtchingIsotropic etching Anisotropic etching

SiO2

SiO2

SiO2

(1)

(2)

(3)

photoresist

photoresist

SiO2

(1)

(2)

photoresist

photoresist

SiO2

SiO2

(3)

wet etch dry etch

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Ion Energy~1 keV to200 keV

Module: Ion Implantation

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ProcessingSteps

Si wafer

What is process integration?• Sequential use of a series of simple process steps or

“modules” to create complex structures

Slide 0-32

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The EE143 Lab Process (part I)

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The EE143 Lab Process (Part II)