photolithography machine control system rit computer engineering senior design project ben...
Post on 31-Mar-2015
213 Views
Preview:
TRANSCRIPT
Photolithography Machine Control System
RIT Computer Engineering Senior Design Project
Ben Conrad February 13, 2004 Mark Edwards
User Interface• Seven Executable Commands
– DEV#1: Dispense developer solution– PREWET: Dispense de-ionized(DI) water– RINSE: Dispenses DI water to clean wafer– N2: Dispenses Stream of Nitrogen (N2)– SPIN: Spin Dry the wafer– WAIT: Static delay option.– END PGM: End the program
• Parameters– Time: .1 – 999.9 sec. (.1 second resolution)– Speed: 0-7,999 RPM
How It Works
The Solitec Model 8360 spin casting and temperature controlled positive develop bake system is used in the photolithography process of making microelectronic circuits on silicon wafers. It automates the process of applying photoresist and baking a wafer, and is fully programmable through user input. This is accomplished through a keypad and LCD display. The user enters a series of operations with parameters on the keypad, thus forming “recipes” for the processing of particular sets of wafers. The main modules visible to the user are the digital display and input keypad, the input wafer cartridge, the chemical application spin chuck, the bake chuck, and the output wafer cartridge.
How We Did It
Parts Used in System I/O Circuit• (1) HCS12 Microcontroller
• (4) 74F675A 16-bit Serial In, Parallel Out Shift Registers
• (2) 74F676 16-bit Parallel In, Serial Out Shift Registers
• (2) LM741 Operational Amplifiers
• (2) DAC0800 8-bit Digital to Analog Converters
Design Goals•Meet customer requirements – system able to hold 10 “recipes” for wafer processing, control wafer speed from 0-8000RPM, timing accurate to 0.1 seconds.
•Allow use on coat and develop tracks – provide recipes general enough for controller to function on either machine
•Save RIT money – our total cost is $500 compared to $25,000 from industry – 98% savings
•Future Expandability
- Software handles extra sensors which may be added later
- System I/O hardware provides twice the I/O needed allowing expansion to machine with more processing stations
Solitec 8360 in RIT’s Fab
Spin Chuck Vacuum Tube
Bake Chuck Vacuum Tube
Wafer Output Cartridge
(25 wafers)
Wafer Input Cartridge
(25 wafers)
Top Down View
¾ Overhead View
Technological Arts’ HSC12 Board
Over 4000 lines of HCS12 assembly code was written to operate both the system and UI HCS12s.
The software controlled the inputs and outputs
diagrammed (left) by expanding the HCS12’s
input and output capabilities through the use of shift registers (below). Dual DAC’s provided analog
signals which controlled the motor speed.
Coating the wafer with photoresist or developing it by wet etching off layers after masking is an essential step in the process of creating microchips. In either track, the control system loads a wafer from the input cartridge, then moves it to the spin chuck. Once on the spin chuck, a vacuum is applied. The spin chuck is then accelerated to anywhere from 0-8000RPM while various chemicals are applied to the wafer. The 8360 has the ability to dispense a main chemical (developer), de-ionized water, and an air stream of nitrogen. When finished, the system moves the wafer to the bake chuck, where the wafer is heated for a variable, user-defined length of time. Finally, the system moves the wafer to the output cartridge, and the wafer is ready to be processed by another system.
B0
HC12- A3
B1
16 Bits to Cable (16-31)
8 Bits to DAC1
A4
Serial Out to HC12
B2
HC12- B4
U5
74F676
4
5
2
6
1
78910111314151617181920212223
SI
MODE
CLK
SO
CS
P0P1P2P3P4P5P6P7P8P9
P10P11P12P13P14P15
HC12-A116 Bits to Cable (0-15)
HC12- B2
B3
HC12- A7
8 Bits to DAC0
B4
Serial Out to HC12
B5
HC12-A2
HC12-A5
U3
74F675A
4
3
5
7891011131415
1617181920212223
6
1
2
SI
R/W
STCP
Q0Q1Q2Q3Q4Q5Q6Q7
Q8Q9
Q10Q11Q12Q13Q14Q15
SO
CS
SHCP
Ben Conrad, Mark Edwards
A3
A6
Schematic: Shift Register to HC12 Connections
16 input Bits (0-15)
HC12- A6
32 Input Bits
A7
U2
74F675A
4
3
5
7891011131415
1617181920212223
6
1
2
SI
R/W
STCP
Q0Q1Q2Q3Q4Q5Q6Q7
Q8Q9
Q10Q11Q12Q13Q14Q15
SO
CS
SHCP
U2
74F675A
4
3
5
7891011131415
1617181920212223
6
1
2
SI
R/W
STCP
Q0Q1Q2Q3Q4Q5Q6Q7
Q8Q9
Q10Q11Q12Q13Q14Q15
SO
CS
SHCP
HC12-A4
16 input Bits (16-31)
A2
HC12- B3
A1
U6
74F676
4
5
2
6
1
78910111314151617181920212223
SI
MODE
CLK
SO
CS
P0P1P2P3P4P5P6P7P8P9
P10P11P12P13P14P15
HC12-A0A0
U2
74F675A
4
3
5
7891011131415
1617181920212223
6
1
2
SI
R/W
STCP
Q0Q1Q2Q3Q4Q5Q6Q7
Q8Q9
Q10Q11Q12Q13Q14Q15
SO
CS
SHCP
HC12- B5
HC12 - P7
16 Bits to Cable (32-47)
HC12 - P6
48 Output Bits
A5
Part Price ($) Quantity Cost40x4 LCD Module w/ Backlight 29 1 294x4 Matrix Keypad 20 1 20
MAX232 (Serial Driver) 4 2 88MHz Crystal 1 2 2
20 Key Encoder 7 1 7
16-Bit Par. In Serial out Shift Register 5 2 1016-Bit Serial in Par. Out Shift Register 9 4 36Misc (wire, connectors, etc) 25 1 25
Misc Chips (DAC0800, LM741, etc) 1 10 10M68HC12 Microcontroller Dev Board. 180 2 360
TOTAL $507
Cost Breakdown
A collaborative effort between RIT Computer Engineering and Microelectronic Engineering Special thanks to: John C. Nash, Dr. Alan D. Raisanen, Thomas J. Grimsley, and Dr. Roy Czernikowski
The top-down diagram shows the wafer input and wafer output cartridges located on opposite ends of the line while the spin chuck and bake chuck are in the center. Vacuum tubes hold the wafers onto each chuck as they are processed. The gray rectangle represents a tray which is able to move between the input and output cartridge for wafer loading and unloading, respectively.
The 3/4th overhead view diagram shows the holes cut into the system tray to allow each chuck to move up or down to allow the tray to move to one of its three positions (at input, center, at output.) Conveyer belts move the wafer from the input assembly and to the output assembly. The black squares represent three switches used for position sensing on the system tray and two vacuum sensors on the vacuum tubes to determine if a wafer is currently making contact with the tube (and thus on the tube’s chuck.)
Control System Block Diagram
System I/O Hardware
Standby M ode 1 2 3 ESC
M ode:_ 4 5 6 SS
1 2 3 7 8 9 NXT
Run Program Service < 0 > ENT
Rec#00 1 2 3 ESC
4 5 6 SS
7 8 9 NXT
< 0 > ENT
Status: RunningBake Time: 000.0 Motor Speed: 0000
Funct: Step: 1 1 2 3 ESC
Rec #: 4 5 6 SS
1 2 3 4 5 6 7 8 9 NXT
DEV PREWET RINSE N2 SPIN WAIT < 0 > ENT
Time:Speed:
1 2 3 ESC
4 5 6 SS
1 2 3 7 8 9 NXT
Manual Op Status Vie w I/O < 0 > ENT
Standby Mode
Run Mode
Program Mode
Status Mode
UI Controller
The Team
Digital Controller – HCS12Analog I/O to Motor Board
Motor Speed In
Next Speed Out
Motor Accel Out
Digital Inputs
Position/Level Switch Sensors
Hot Plate at Temp.
No more wafers to processWafer sender ready
Wafer receiver cassette fullWafer receiver ready
Digital OutputsStore finished wafer
Load next incoming wafer
Solenoid Outputs
Servo BoardMotor RPMDetect
Switch Sensors
Entrance Wafer
Cassette Holder
Exit Wafer Cassette Holder
Solenoids
Hot Plate
HC11 SPI Interface
ClkSDI/MISO
SDO/MOSI
LCD Panel
Keypad
HCS 12
top related