exam 1 friday sept 22 - iowa state universityclass.ece.iastate.edu/ee330/lectures/ee 330 lect 10...
TRANSCRIPT
![Page 1: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/1.jpg)
Exam 1 Friday Sept 22
• Students may bring 1 page of notes
• Next weeks HW assignment due on Wed Sept 20 at beginning of class
• No 5:00 p.m extension so solutions can be posted
• Those with special accommodation needs, please send me an email
message or contact me so arrangements can be made
• Review session - time to be announced
![Page 2: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/2.jpg)
EE 330
Lecture 10
IC Fabrication Technology Part III
− Metalization and Interconnects
− Parasitic Capacitances
− Back-end Processes
Devices in Semiconductor Processes
− Resistors
− Diodes
![Page 3: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/3.jpg)
IC Fabrication Technology
• Crystal Preparation
• Masking
• Photolithographic Process
• Deposition
• Etching
• Diffusion
• Ion Implantation
• Oxidation
• Epitaxy
• Polysilicon
• Planarization
• Contacts, Interconnect and Metalization
Review from Last Lecture
![Page 4: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/4.jpg)
Contacts
Vulnerable to pin holes(usually all contacts are same size)
A A’
Unacceptable Contact
B
B’
Acceptable Contact
Review from Last Lecture
![Page 5: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/5.jpg)
Contacts
Acceptable Contact
B
B’
Review from Last Lecture
![Page 6: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/6.jpg)
Contacts
2λ
1.5λ
2λ
1.5λ
Design Rule Violation
2λ
“Dog Bone” Contact
![Page 7: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/7.jpg)
Contacts
Common
Circuit
Connection
Standard Interconnection Buried Contact
Can save area but not
allowed in many processes
![Page 8: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/8.jpg)
Metalization
• Aluminum widely used for interconnect
• Copper often replacing aluminum in recent
processes
• Must not exceed maximum current density
– around 1ma/u for aluminum and copper
• Ohmic Drop must be managed
• Parasitic Capacitances must be managed
• Interconnects from high to low level metals
require connections to each level of metal
• Stacked vias permissible in some processes
![Page 9: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/9.jpg)
Metalization
Aluminum
• Aluminum is usually deposited uniformly over entire surface and
etched to remove unwanted aluminum
• Mask is used to define area in photoresist where aluminum is to be
removed
Copper
• Plasma etches not effective at removing copper because of absence
of volatile copper compounds
• Barrier metal layers needed to isolate silicon from migration of
copper atoms
• Damascene or Dual-Damascene processes used to pattern copper
![Page 10: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/10.jpg)
Patterning of Aluminum
PhotoresistContact Opening
from Mask
![Page 11: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/11.jpg)
Patterning of Aluminum
PhotoresistContact Opening
after SiO2 etch
![Page 12: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/12.jpg)
Patterning of Aluminum
PhotoresistContact Opening
after SiO2 etch
![Page 13: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/13.jpg)
Patterning of Aluminum
Metal Applied to Entire Surface
![Page 14: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/14.jpg)
Patterning of Aluminum
Photoresist Patterned
with Metal Mask
![Page 15: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/15.jpg)
Patterning of Aluminum
Aluminum After Metal Etch
(photoresist still showing)
![Page 16: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/16.jpg)
Copper Interconnects
Limitations of Aluminum Interconnects
• Electromigration
• Conductivity not real high
Relevant Key Properties of Copper
• Reduced electromigration problems at
given current level
• Better conductivity
Challenges of Copper Interconnects• Absence of volatile copper compounds
(does not etch)
• Copper diffuses into surrounding
materials (barrier metal required)
![Page 17: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/17.jpg)
Source:
Sept 13, 2017
![Page 18: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/18.jpg)
![Page 19: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/19.jpg)
![Page 20: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/20.jpg)
Copper Interconnects
Practical methods of realizing copper
interconnects took many years to
develop
Copper interconnects widely used in
some processes today
![Page 21: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/21.jpg)
Patterning of Copper
PhotoresistContact Opening
after SiO2 etch
Damascene Process
![Page 22: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/22.jpg)
Patterning of Copper
Tungsten (W)
Damascene Process
CMP Target
W has excellent conformality when formed from WF6
![Page 23: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/23.jpg)
Chemical-Mechanical Planarization (CMP)
http://en.wikipedia.org/wiki/Chemical-mechanical_planarizationAcknowledgement:
• Polishing Pad and Wafer Rotate in
non-concentric pattern to thin, polish,
and planarize surface
• Abrasive/Chemical polishing
• Depth and planarity are critical
![Page 24: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/24.jpg)
Patterning of Copper
W-plug
Damascene Process
CMP TargetAfter first CMP Step
![Page 25: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/25.jpg)
Patterning of CopperDamascene Process
Oxidation
After first CMP Step
![Page 26: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/26.jpg)
Patterning of CopperDamascene Process
Photoresist Patterned with
Metal Mask Defines Trench
![Page 27: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/27.jpg)
Patterning of CopperDamascene Process
Shallow Trench after Etch
W-plug
![Page 28: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/28.jpg)
Patterning of CopperDamascene Process
(Barrier metal added before copper to contain the copper atoms)
Barrier
Metal
![Page 29: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/29.jpg)
Patterning of CopperDamascene Process
Copper DepositionW-plug
![Page 30: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/30.jpg)
Patterning of CopperDamascene Process
Copper DepositionW-plug
CMP Target
Copper is deposited or electroplated (Barrier Metal Used for Electroplating Seed)
![Page 31: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/31.jpg)
Patterning of CopperDamascene Process
After Second CMP Step
W-plug
CMP Target
Copper
![Page 32: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/32.jpg)
Patterning of Copper
PhotoresistShallow Trench Defined
in PR with Metal Mask
Dual-Damascene Process
![Page 33: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/33.jpg)
Patterning of Copper
PhotoresistShallow Trench After Etch
Dual-Damascene Process
![Page 34: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/34.jpg)
Patterning of Copper
PhotoresistVia Defined in PR
with Via Mask
Dual-Damascene Process
![Page 35: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/35.jpg)
Patterning of Copper
PhotoresistVia Etch Defines
Contact Region
Dual-Damascene Process
(Barrier Metal added before copper but not shown)
![Page 36: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/36.jpg)
Patterning of Copper
Copper Deposited on Surface
Dual-Damascene Process
Copper is deposited or electroplated (Barrier Metal Used for Electroplating Seed)
![Page 37: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/37.jpg)
Patterning of Copper
Copper Deposited on Surface
Dual-Damascene Process
CMP Target
![Page 38: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/38.jpg)
Patterning of Copper
Copper Interconnect
Dual-Damascene Process
CMP Target
Copper Via
![Page 39: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/39.jpg)
Patterning of Copper
Dual-Damascene Process
Both Damascene Processes Realize Same Structure
Damascene ProcessTwo Dielectric Deposition Steps
Two CMP Steps
Two Metal Deposition Steps
Two Dielectric Etches
W-Plug
One Dielectric Deposition Steps
One CMP Steps
One Metal Deposition Steps
Two Dielectric Etches
Via formed with metal step
![Page 40: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/40.jpg)
Multiple Level Interconnects
3-rd level metal connection to n-active without stacked vias
![Page 41: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/41.jpg)
Multiple Level Interconnects
3-rd level metal connection to n-active with stacked vias
![Page 42: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/42.jpg)
Metalization
Interconnect Layers May Vary in Thickness or Be Mostly Uniform
12.5μ
![Page 43: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/43.jpg)
Interconnects
• Metal is preferred interconnect
– Because conductivity is high
• Parasitic capacitances and resistances of concern in all interconnects
• Polysilicon used for short interconnects
– Silicided to reduce resistance
– Unsilicided when used as resistors
• Diffusion used for short interconnects
– Parasitic capacitances are high
![Page 44: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/44.jpg)
Interconnects
• Metal is preferred interconnect
– Because conductivity is high
• Parasitic capacitances and resistances of concern in all interconnects
• Polysilicon used for short interconnects
– Silicided to reduce resistance
– Unsilicided when used as resistors
• Diffusion used for short interconnects
– Parasitic capacitances are high
![Page 45: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/45.jpg)
Resistance in Interconnects
L
W
H
A
B
BA
R
![Page 46: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/46.jpg)
Resistance in Interconnects
L
W
HA
B
BD
R
D
ρA
LR
A=HW
ρ independent of geometry and
characteristic of the process
![Page 47: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/47.jpg)
Resistance in Interconnects
L
W
HA
B
D
H
ρ
W
Lρ
A
LR
H << W and H << L in most processes
Interconnect behaves as a “thin” film
Sheet resistance often used instead of conductivity to characterize film
R□=ρ/H R=R□[L / W]
![Page 48: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/48.jpg)
Resistance in Interconnects
R=R□[L / W]
L
W
The “Number of Squares” approach to resistance determination in thin films
1 2 3 21NS = 21
L / W=21
R=R□NS
![Page 49: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/49.jpg)
Resistance in Interconnects
R=R□13.25
Corners Contribute
about .55 Squares
Fractional Squares
Can Be Represented
By Their Fraction
In this example:
NS=12+.55+.7=13.25
The “squares” approach is not exact but is good enough for
calculating resistance in almost all applications
![Page 50: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/50.jpg)
Example:
The layout of a film resistor with electrodes A and B is shown. If
the sheet resistance of the film is 40 Ω/□, determine the
resistance between nodes A and B.
10u
3u1u
A
B
![Page 51: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/51.jpg)
10u
3u1u
A
B
Solution
NS =9+9+3+2(.55)=22.1
RAB=R□NS=40x22.1=884Ω
![Page 52: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/52.jpg)
Resistance in Interconnects(can be used to build resistors!)
• Serpentine often used when large resistance required
• Polysilicon or diffusion often used for resistor creation
• Effective at managing the aspect ratio of large resistors
• May include hundreds or even thousands of squares
![Page 53: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/53.jpg)
Resistance in Interconnects(can be used to build resistors!)
d1
2d
2
Area requirements determined by both minimum
width and minimum spacing design rules
![Page 54: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/54.jpg)
Capacitance in Interconnects
C=CDA
CD is the capacitance density and A is the area of the overlap
![Page 55: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/55.jpg)
Capacitance in Interconnects
Metal 1
Metal 2
Substrate
A1
A4
A2
A3
A5
C12
C2S
C1S
M1
M2
SUB
Equivalent Circuit
C12=CD12 A5
C1S=CD1S (A1+A2+A5)
C2S=CD2S (A3+A4)
![Page 56: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/56.jpg)
Example
Two metal layers, Metal 1 and Metal 2, are shown. Both are
above field oxide. Determine the capacitance between Metal
1 and Metal 2. Assume the process has capacitance densities
from M1 to substrate of .05fF/u2, from M1 to M2 of .07fF/u2 and
from M2 to substrate of .025fF/u2.
30µ
30µ
30µ
30µ
10µ
10µ
Metal 1
Metal 2
![Page 57: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/57.jpg)
Example
The capacitance density from M1 to M2 is .07fF/u2
30µ
30µ
30µ
30µ
10µ
10µ
Solution
30µ
22
C1C2 400μ20μA
28fF0.07fF/400CAC 22
D12C1C212
![Page 58: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/58.jpg)
Capacitance and Resistance in
Interconnects
• See MOSIS WEB site for process
parameters that characterize parasitic
resistances and capacitances
www.mosis.org
![Page 59: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/59.jpg)
![Page 60: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/60.jpg)
![Page 61: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/61.jpg)
![Page 62: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/62.jpg)
![Page 63: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/63.jpg)
![Page 64: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/64.jpg)
Example
Determine the resistance and capacitance of a Poly interconnect that is
0.6u wide and 800u long and compare that with the same
interconnect if M1 were used.
0.6µ
800µ
POLY
POLY SQ SHR =n R
P-SUB DPSC =A•C
RSH=?
RDPS=?
![Page 65: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/65.jpg)
RSH=23.5Ω/□
CDPS=84 af/µ2
![Page 66: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/66.jpg)
Example
Determine the resistance and capacitance of a Poly interconnect that is
0.6u wide and 800u long and compare that with the same
interconnect if M1 were used.
0.6µ
800µ
8001333
0 6.SQ
n
20 6 800 480A= .
POLY SQ SHR =n R =23.5•1333=31.3KΩ
2 -2
P-SUB DPSC =A•C =480μ •84aFμ =40.3fF
POLY
![Page 67: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/67.jpg)
Example
Determine the resistance and capacitance of a Poly interconnect that is
0.6u wide and 800u long and compare that with the same
interconnect if M1 were used.
0.6µ
800µ
Metal 1
![Page 68: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/68.jpg)
RSH=0.09Ω/□
CDPS=27 af/µ2
![Page 69: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/69.jpg)
Example
Determine the resistance and capacitance of a Poly interconnect that is
0.6u wide and 800u long and compare that with the same
interconnect if M1 were used.
0.6µ
800µ
8001333
0 6.SQ
n
20 6 800 480A= .
M1 SQ SHR =n R =0.09•1333=120Ω
2 -2
M1-SUB DM1SC =A•C =480μ •27aFμ =13.0fF
Metal 1
![Page 70: Exam 1 Friday Sept 22 - Iowa State Universityclass.ece.iastate.edu/ee330/lectures/EE 330 Lect 10 Fall 2017.pdf · Exam 1 Friday Sept 22 ... • Next weeks HW assignment due on Wed](https://reader031.vdocuments.site/reader031/viewer/2022030904/5b4619877f8b9af5078b52fc/html5/thumbnails/70.jpg)
End of Lecture 10