240-451 VLSI , 2000

1

Lecture Lecture 1 1

A review of microelectronics and an introductionto MOS technology

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

240-451 VLSI , 2000

2

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Why VLSI?

Introduction to integrated circuit technology- Affected by electronics engineering technology- Characterization of electronics at present-day

integration improved the design reduces manufacturing cost

240-451 VLSI , 2000

3

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

From design to market

Circuit Design Layout

Fabrication

Packaging Test Packaging

240-451 VLSI , 2000

4

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Integrated circuit (IC) era

Moore’s law : number of transistors per chip doublesevery year

240-451 VLSI , 2000

5

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

IC technology scaling

240-451 VLSI , 2000

6

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Metal-oxide-semiconductor

MOS = Metal Oxide Semiconductor

In the past : Metal gate over Oxide insulationPresent-day : polycrystalline silicon that we call

“Poly”

We use metal (aluminum) for interconnection wires on the surface of the chip.

240-451 VLSI , 2000

7

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI design process

1. Specification : Defined function, estimate cost

Adder

2. Architecture : Large block

Partition must be added in good design process if the circuit has complexity.

240-451 VLSI , 2000

8

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI design process

3. Logic :we can divide into 3 steps - Describe the behavior of circuit (Input, Output and behavior

C = A + B- Describe the structure of circuit

R 1 R 2 R 3

Adder

A B

240-451 VLSI , 2000

9

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI design process

- Detail design

R 1 R 2 R 3

A B

240-451 VLSI , 2000

10

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI design process

4. Circuit Transistor : Speed, power

5. Layout :

Now we are in those 2 process (process 4 and 5 )

240-451 VLSI , 2000

11

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

ArchitecturalLogic

Circuit

Behavioral Structural

Physical

device Today’s view

Relation in design process

240-451 VLSI , 2000

12

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Design Technology

240-451 VLSI , 2000

13

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI Technology

1. Schottky TTL (Transistor-transistor logic)

A

B

C= A * B

Vcc

240-451 VLSI , 2000

14

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI Technology

2. ECL (Emitter coupled logic)

C= A + B

Vcc

C= A + B

A B

-V EE

NOR

240-451 VLSI , 2000

15

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

3. MOS (Metal Oxide semiconductor)

VLSI Technology

VDD

C = A + BBA

NOR

240-451 VLSI , 2000

16

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

VLSI Technology

4. CMOS (Complementary MOS)

VDD

C = A + BA

B

240-451 VLSI , 2000

17

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Transistor Structure

240-451 VLSI , 2000

18

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Manufacturing Steps

240-451 VLSI , 2000

19

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Photolithography

Diffusion = High temperatureIon implementation = High velocity

240-451 VLSI , 2000

20

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Process Steps

p-tub n-tub

substrate

Doped substrate for n-type, p-type transistor

240-451 VLSI , 2000

21

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Process Steps (con’t)

Pattern polysilicon before diffusion regions:

p-tub n-tub

poly polygate oxide

240-451 VLSI , 2000

22

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Process Steps (con’t)

p-tub n-tub

poly poly

n+n+ p+ p+

Add diffusions, performing self-masking:

240-451 VLSI , 2000

23

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Process Steps (con’t)

p-tub n-tub

poly poly

n+n+ p+ p+

metal 1 metal 1

vias

Start adding metal layers:

240-451 VLSI , 2000

24

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

NMOS Process

240-451 VLSI , 2000

25

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Transistor Layout

n-type (tubs may vary):

w

L

240-451 VLSI , 2000

26

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

N-well CMOS Process

240-451 VLSI , 2000

27

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

N-well CMOS Process (con’t)

240-451 VLSI , 2000

28

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

CMOS Transistor layout

240-451 VLSI , 2000

29

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

MOS Symbol

nMOS nMOS pMOSenhancement depletion enhancement

240-451 VLSI , 2000

30

Department of Computer Engineering, Prince of Songkla University by Wannarat Suntiamorntut

Discussion and Question