Diffusion Furnace Controller Design

DIFFUSION FURNACE CONTROLLER DESIGN

Team 14 Joe GradyJames CrowHongyu ChenPrakalp SudhakarVictor Villagomez

Client/Faculty Advisor: Dr. Gary Tuttle

PROBLEM STATEMENTThe objective of the senior design project is to design a new set of temperature

controllers to use on a set of diffusion furnaces located at the Microelectronics

Research Center.

The project goals include:

• Temperature calibration of the furnaces

• Implementing of new temperature controllers into the current furnace system

• Providing a computer interface so that temperature of the furnaces can be

controlled and monitored remotely.

SYSTEM OVERVIEW

FUNCTIONAL REQUIREMENTS

• Controller must have a temperature tolerance within +/- 1 degree Celsius

• Controller must be digital and programmable (∆T/ ∆t)

• Controller must have communication capability

• Controller must be able to sample and store information for every cycle

• Controller must be able to control temperatures independently of each section

FUNCTIONAL REQUIREMENTS

• Software must be able to monitor and control the parameters of the temperature controller

• Software must be able to support simultaneous use by multiple students

• Software must be able to display graphs of the process

• Software needs to be accessed online via web browser

• Graphical interface of the software must be user-friendly

• Error checking and deviation

NON-FUNCTIONAL REQUIREMENTS

• The new controllers need to be placed where the old ones were so they need to able to fit within a certain space

• Connectors must be compatible with the new controller

• All the schematics and layout designs need to be of industry standards for future reference.

RISKS AND MITIGATIONS• Group might possibly lose members• No way to verify that the wafer is

placed in the correct oven• The amount of inputs on the CN616

controller will not allow us to use all of thermocouples used in the current set-up.

BUDGET

Parts and Materials: a) Suitable controller(s) b) Miscellaneous parts c) Poster

Without Labor$1,250.00$50.00$50.00

With Labor$1,250.00$50.00$50.00

Services:a)Website Upkeep (for 1 year) $60.00 $60.00Labor ($12.50 per hour):a)Crow, James b)Villagomez, Victorc)Sudhakar, Prakalpd)Grady, Joee)Chen, Hongyu

$1125.00$1125.00$1125.00$1125.00$1125.00

Parts and Materials: a) Suitable controller(s) b) Miscellaneous parts c) Poster

Without Labor$620.00$0.00$0.00

With Labor$620.00$0.00$0.00

Services:a)Website Upkeep (for 1 year) $0.00 $0.00Labor ($12.50 per hour):a)Crow, James b)Villagomez, Victorc)Sudhakar, Prakalpd)Grady, Joee)Chen, Hongyu

$375.00$375.00$375.00$375.00$375.00

Current Expenses

Total Expected Expenses

SCHEDULE – 1ST SEMESTER

SOFTWARE ARCHITECTURE

SOFTWARE ARCHITECTURE – SEQUENCE DIAGRAM

SOFTWARE ARCHITECTURE – USE CASES

SOFTWARE OVERVIEW

USER INTERFACE

All text field have a

acceptable range

SOFTWARE TEST PLAN

Simulation• CubicTest Tools

A graphical Eclipse plug-in For writing Selenium and Watir tests.

• Catus A simple framework for unit testing server-side code. It use JUnits and extends it.

• JMeter A full multithreading framework allows concurrent sampling. GUI interface for user friendly.

SOFTWARE TEST PLAN

What to test

• Website Application Module (user side)• Internet Server Module (between the server and the

website)• Communication Module (between server and controller)Metrics & Hypothesis

• Assume all hardware are working correctly • Test extreme cases --- like negative values and value out of range• Match corresponding protocols to the parameters

PROTOTYPE IMPLEMENTATION OF SERIAL COMMUNICATION

• Baud Rate = 4800• Data Bits = 8• Parity = N• Stop = 1

Operating Protocol• Controllers do not initiate

communication, Command Module does.

• All communication is in ASCII format

• To start communication Command Module sends alert code followed by ID

SCHEMATIC – OLD CONTROLLER

HARDWARE INTERFACE ISSUES

• SCR data sheets are unavailable and we are required to create test to determine the characteristics of the SCR.

• To control the SCR pairs we will need an op-amp interface circuit between the CN616 controller and the SCR’s gates.

THERMOCOUPLE INTERFACING

RS-232 INTERFACING

PROTOTYPE SCR INTERFACING

Omega CN616 – 1 output SCR

Pair

HARDWARE TEST PLAN

• Isolate a single SCR for characteristic testing to get its turn-on gate voltage

• Use this information to help interface the CN616 controller to the SCR circuit

• Test a single furnace with both a single thermocouple and the SCR circuit connected to the controller. Using a thermometer to compare controller measured temperature and actual temperature.

HARDWARE TEST PLANThermocouple

• Connect the master thermocouple pair (J2) to the CN616 controller input (Z2).

• Check that the 120VAC line voltage is properly connected to the CN616 controller, if so power it on.

• Once the CN616 is powered on set the controller’s 4th digit in the 4 digit model code to 6 as shown in Figure 4-2 below. This will correspond to an S-type thermocouple.

Figure 4-2, Function Setting

• Connect a multi-meter with the red lead connected to the thermocouples red wire and the black lead to ground to verify that the voltages are between 0-40mV.

HARDWARE TEST PLANSCR • Connect the center SCR gates to the op-amp circuits output’s

and then connect the op-amp circuit’s input to the CN616 controller output (Z2)

• Check that both the master thermocouple pair (J2) is connected to the CN616 controller input (Z2) and that the 120VAC line voltage is properly connected to the CN616 controller, if so power it on.

• Use CN616 manual, pages 33-34 to set the temperature to 1000° Celsius at a ramp up time of 20 minutes.

• Connect a multi-meter in series with the output of the CN616 and the op-amp circuit input to verify that the current does not exceed 10mA.

CURRENT PROJECT STATUS

• Thermocouple, AC line power, RS 232 have been all successfully interfaced and verified compatible.

• The tests have been developed for creating the SCR characteristics.

• The Op-amp interface circuit between the CN616 controller output and the input to the SCR gate has been designed and is in the process of being debugged.

• The software design module is setup.• The core test cases have been written, there is

need for more test cases.• The controller can already be tested for

communication

SCHEDULE – 2ND SEMESTER

RESOURCES

Professor• Thorough knowledge about current

microcontrollers, and advice for digital microcontrollers

User Manuals• Manual for current analog microcontrollers• Manual for new digital microcontroller.Manufacturers• Websites to purchase new digital

microcontrollers• Omega.com – New microcontroller• Easysw.com – Serial Programming Guide

QUESTIONS ?