EE143 Microfabrication Technology

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EE143Microfabrication Technology

• Professor Ali Javey
• ajavey_at_eecs.berkeley.edu
• 506 Cory Hall
• [phone]
• TAs SangHoon Lee, leesh_at_me.berkeley.edu
• Peter Matheu, peter_matheu_at_berkeley.edu
• John Wyrwas, jwyrwas_at_eecs.berkeley.edu
• Web Page http//www-inst.eecs.berkeley.edu/ee143
  /

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Schedule

• Lectures Tue/Thu, 330pm-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 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

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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, 1230pm-330pm
• Open book and notes
• No makeups

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 lt40
30
10
30
30
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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.

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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)
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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_at_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 arent 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 gt 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 (contd)

• 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.
  Dont 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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Lab Floor Plan
Note Not drawn to scale
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EE143 Overview

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

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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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Electrical Functionality / Characterization

• The resulting structures may be characterization
  electrically or mechanically

17-stage Ring Oscillator
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MEMS Actuators
Gear Speed Reduction Unit
Movable Mirror
Responsive Drug Delivery Valve
Turbine engine
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Introduction to Si ProcessingEE143 in one day
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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...
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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)
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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.

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Cleanroom Standards
Federal Standard Class Limits
CLASS MEASURED PARTICLE SIZE (MICROMETERS) MEASURED PARTICLE SIZE (MICROMETERS) MEASURED PARTICLE SIZE (MICROMETERS) MEASURED PARTICLE SIZE (MICROMETERS) 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?
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Introduction to Device Fabrication
Oxidation
Lithography Etching
Ion Implantation
Annealing Diffusion
Deposition
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Oxidation of Silicon
Dry Oxidation
Si O2 ? SiO2 Si 2H2O ? SiO2 2H2
Thin oxide
Wet Oxidation
Thick oxide
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Oxidation of Silicon
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Lithography
Development
Resist Coating
Positive resist
Negative resist
Photoresist






Oxide
Si


(a)
Si
Si
Deep Ultraviolet Light


(c)


Optical Lens system
Photomask with opaque and clear patterns


Si
Si



(d)
Exposure
Etching and Resist Strip
(b)
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Pattern TransferEtching
wet etch
dry etch
Isotropic etching
Anisotropic etching
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Module Ion Implantation
Ion Energy 1 keV to 200 keV
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What is process integration?

• Sequential use of a series of simple process
  steps or modules to create complex structures

Si wafer
Processing Steps
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The EE143 Lab Process (part I)
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The EE143 Lab Process (Part II)