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Sample Inter Office Memo - DOC by uup16732


Sample Inter Office Memo document sample

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									               Spartan Semiconductor Services, Inc.
               One Washington Square, San Jose, CA 95192

InterOffice Memo

To:         All Employees
From:       Emily L. Allen
Date:       November 2003
Subject:    Group Device Test Project

Your last remaining group project is Device Testing. In preparation for testing, as well as
for the writing of your individual final reports, your team needs to develop and document
your strategy for S3I Device testing.
Each SSSI wafer has on it four different types of device cells, a logic cell and a materials
cell. Device 1 cells is repeated 16 times on the wafer. Device 2 cell is repeated 16 times.
Device 3 and Device 4 cells are repeated 19 times. The Materials cell is repeated 16
times on the wafer.
Each cell has within it a number of different devices. For example, Device 1 cell has 10
transistors around the outside and 4 BJTs inside the cell. Documentation for each cell can
be found in the bound book of Mask Documentation available in the lab. You can also
download this (very large) file from the website.
Can your team test all of the devices on all of the wafers? Assuming 15 minutes per
device, using the tester for 40 hours per week, that would take more than a year.
So, what should you test? There are many options, and your team must decide on a
strategy. Your first question should be, “What is the purpose of the testing? What
question are we trying to answer?” Depending on the question, you could develop a
number of different strategies. For example, if your question is: “What is the wafer to
wafer difference in threshold voltage of the 32-micron gate length transistors?”, then your
strategy must include testing some number of transistors on every wafer. If your question
is “How much variability is there between the same transistor design on different areas of
the wafer?” Then you should focus on one wafer, or a small number of wafers, and try to
identify the uniformity across the wafer. If your question is: “How variable was the n-
type doping process across a single wafer?”, then you might just test the n-type resistors
on a single wafer.
Your Spartan Semiconductor Team should be sub-divided into Testing Teams of two or
three students. Each Testing Team is responsible for coming up with a device testing
strategy. The results of this testing will be used by both individuals in their individual
written final reports. In addition, all of the Testing Teams need to agree as a class on
how to jointly utilize the real estate on the wafers. For example, there are typically 5
device wafers to test, but each lab section may have 4 to 6 different Testing Teams.
Testing a block often scratches the metal on the pads, so each Testing Team should have
designated certain blocks on each wafer that “belong” to them. You can do this by

Group Device Test Project                 8/2/2011                                    Page 2

drawing a schematic of the wafer with its blocks and designating them to different
Testing Teams. Alternatively, your section could decide just to assign one wafer to each
Your Testing Team needs to decide this week what two questions you want to answer by
your testing, develop an overall strategy to answer the questions, and sign up for testing
hours in the lab.
Note that the final written reports must explain the electrical test results and how they
relate to the processing steps.
The Team should turn in one copy of the attached page:
1. A list of three questions you are trying to answer in your testing.
2. Your testing protocol to answer those questions.
3. An explanation of how the testing will be accomplished by the members of the group,
   including a specific schedule with names attached.
Please also note:
1. First review the manual for the HP4145. This unit has many capabilities and it will
   give you ideas of what to try and how to test.
2. This mask set is new and not all of these devices have been measured before.
3. It is easy to punch through if your test voltage is too high. This can destroy a device.
4. The ring oscillator will require an oscilloscope and a voltage source. In addition, the
   logic devices will also best be tested with a signal generator.
5. The capacitor test equipment may or may not be available.
6. Each team must measure at least two different types of devices, i.e. resistors, diodes,
   transistors, logic circuits.

Group Device Test Project               8/2/2011                                 Page 3

Team Name

Questions your testing will answer:


Testing protocol for each question: (Please add additional pages as necessary)




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