Individual Progress Report

Description

The Individual Progress Report (IPR) is a chance to put your contributions to the team's progress in writing. The report will discuss not only the components and subsystems you have personally been responsible for, but what components you have helped work on as well. It is important to talk about the relation between your work and your teammates' work as well.

Requirements and Grading

This report should be 5-12 pages of your own work. This means that you cannot take paragraphs/text from your Design Review document, since that was a collaborative effort. The IPR Grading Rubric describes what we look for in grading this assignment. The requirements are expanded on below:

  1. General: Concise writing is encouraged, but it is important that all pertinent information is conveyed. All figures should be labeled and formatted consistently.
  2. Formatting: Please refer to the Final Report Guidelines for general writing guidelines, since the format of this report should be very similar to that of the final report. Note that each component of the Final Report may be tailored to the parts of the project the individual has been active in.
  3. Introduction: First, discuss what portion of the system you have been active in designing connects to which portion of a different subsystem, and how these interact to complete an overall objective. Then discuss what you have accomplished, what you are currently working on, and what you still have left to do.
  4. Design: Discuss the design work you have done so far. It is expected that you have done calculations and/or found relevant equations, created circuits for your parts of the project, and simulated / drawn schematics for your parts. You may have already, at a high level, discussed how your part fits into the rest of the project, but you should expand on the technical details and interface between your module(s) and the other modules of the project.
  5. Verification: Testing and verification is also very important. Make sure you describe each test that was performed and its procedure in detail, and give quantitative, meaningful results. Also describe tests that have yet to be performed. We should be convinced that if all your tests will pass, your part of the project will work.
  6. Conclusion: Discuss a plan and timeline for completing your responsibilities and your project as a whole. Also explain the ethical considerations of your project by consulting the IEEE Code of Ethics, ACM Code of Ethics, or another relevant Code of Ethics.
  7. Citations: You need citations. Cite sources for equations, Application Notes you referenced in your design, and any literature you used to help design or verify your work. If you checked something from another course's lecture slides, Google'd for things related to your project, or anything similar, then you have something you need to cite. At the very least, since you have talked about the ethical considerations of your project as it relates to a published code of ethics (e.g., IEEE or ACM), you should cite those!

Submission and Deadlines

The IPR should be submitted on canvas in PDF format by the deadline listed on the Course Calendar.

Four Point Probe

Simon Danthinne, Ming-Yan Hsiao, Dorian Tricaud

Four Point Probe

Featured Project

# Four Point Probe

Team Members:

Simon Danthinne(simoned2)

Ming-Yan Hsiao(myhsiao2)

Dorian Tricaud (tricaud2)

# Problem:

In the manufacturing process of semiconductor wafers, numerous pieces of test equipment are essential to verify that each manufacturing step has been correctly executed. This requirement significantly raises the cost barrier for entering semiconductor manufacturing, making it challenging for students and hobbyists to gain practical experience. To address this issue, we propose developing an all-in-one four-point probe setup. This device will enable users to measure the surface resistivity of a wafer, a critical parameter that can provide insights into various properties of the wafer, such as its doping level. By offering a more accessible and cost-effective solution, we aim to lower the entry barriers and facilitate hands-on learning and experimentation in semiconductor manufacturing.

# Solution:

Our design will use an off-the-shelf four point probe head for the precision manufacturing tolerances which will be used for contact with the wafer. This wafer contact solution will then be connected to a current source precisely controlled by an IC as well as an ADC to measure the voltage. For user interface, we will have an array of buttons for user input as well as an LCD screen to provide measurement readout and parameter setup regarding wafer information. This will allow us to make better approximations for the wafer based on size and doping type.

# Solution Components:

## Subsystem 1: Measurement system

We will utilize a four-point probe head (HPS2523) with 2mm diameter gold tips to measure the sheet resistance of the silicon wafer. A DC voltage regulator (DIO6905CSH3) will be employed to force current through the two outer tips, while a 24-bit ADC (MCP3561RT-E/ST) will measure the voltage across the two inner tips, with expected measurements in the millivolt range and current operation lasting several milliseconds. Additionally, we plan to use an AC voltage regulator (TPS79633QDCQRQ1) to transiently sweep the outer tips to measure capacitances between them, which will help determine the dopants present. To accurately measure the low voltages, we will amplify the signal using an JFET op-amp (OPA140AIDGKR) to ensure it falls within the ADC’s specifications. Using these measurements, we can apply formulas with corrections for real-world factors to calculate the sheet resistance and other parameters of the wafer.

## Subsystem 2: User Input

To enable users to interact effectively with the measurement system, we will implement an array of buttons that offer various functions such as calibration, measurement setup, and measurement polling. This interface will let users configure the measurement system to ensure that the approximations are suitable for the specific properties of the wafer. The button interface will provide users with the ability to initiate calibration routines to ensure accuracy and reliability, and set up measurements by defining parameters like type, range, and size tailored to the wafer’s characteristics. Additionally, users can poll measurements to start, stop, and monitor ongoing measurements, allowing for real-time adjustments and data collection. The interface also allows users to make approximations regarding other wafer properties so the user can quickly find out more information on their wafer. This comprehensive button interface will make the measurement system user-friendly and adaptable, ensuring precise and efficient measurements tailored to the specific needs of each wafer.

## Subsystem 3: Display

To provide output to users, we will utilize a monochrome 2.4 inch 128x64 OLED LCD display driven over SPI from the MCU. This display will not only present data clearly but also serve as an interface for users to interact with the device. The monochrome LCD will be instrumental in displaying measurement results, system status, and other relevant information in a straightforward and easy-to-read format. Additionally, it will facilitate user interaction by providing visual feedback during calibration, measurement setup, and polling processes. This ensures that users can efficiently navigate and operate the device, making the overall experience intuitive and user-friendly.

# Criterion for Success:

A precise constant current can be run through the wafer for various samples

Measurement system can identify voltage (10mV range minimum) across wafer

Measurement data and calculations can be viewed on LCD

Button inputs allow us to navigate and setup measurement parameters

Total part cost per unit must be less than cheapest readily available four point probes (≤ 650 USD)

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