EE 432/532Final Report – CyMOS process

May 5, 2017

Group x

George WashingtonAbraham LincolnThomas Jefferson

Theodore Roosevelt

Lab instructor – Donald Trump (soon to be on Mt. Rushmore, also)

OverviewWrite an overview or synopsis of the CyMOS process as it went for your group. (Should be more than two sentences but shorter than one page.)

Processing details

1. Starting wafers – number, type, resistivity, doping level.2. Field oxide

a. Describe the purpose of the field oxide and the design goals. List your desired oxide thickness and the time and temperature you chose to use. (Put the calculations in an ap-pendix.)

b. Standard Clean – Explain the purpose of the standard clean and summarize the basic pro-cedure.

c. Wet Oxidation – Summarize the basic steps of the wet oxide growth process.d. Results – Summarize the operation of the Filmetrics system. List your measured oxide

thickness, including the wafer map. Describe any problems encountered in the lab.

3. Lithography for pwella. Describe the purpose of the pwell lithographyb. Summarize the lithography process. Give some detail, but DO NOT simply provide a

step-by-step recounting of the SOP.c. Results – Include photographs. Describe any problems / anomalies encountered.

4. Boron diffusion for pwella. Describe the purpose of the pwell diffusion and the design goals. Include predicted sur-

face concentration, junction depth and oxide thicknesses. (Put the calculations in an ap-pendix.) Include a graph of the diffusion profile. (Can be from the diffusion excel calcu-lator.)

b. Standard Clean – Don’t summarize. Simply state that the standard clean was identical to that done prior to the field oxidation and refer the reader to section 2-b.

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c. Diffusion deposition and drive – Summarize the basic steps of the diffusion process. Don’t forget to include the LTO and oxidation portions.

d. Results – List your measured oxide thickness. Include the measured sheet resistance. (both from 4PP and TLM 1). Describe any problems / anomalies encountered during the diffusion.

5. Lithography for PMOS source and draina. Describe the purpose of the PMOS lithographyb. Refer the reader to the lithography description in Sec. 3-b. Include appropriate comments

about the need for alignment.c. Results – Include photographs. Describe any problems / anomalies encountered.

6. Boron diffusion for PMOS source and draina. Describe the purpose of the PMOS diffusion and the design goals. Include predicted sur-

face concentration, junction depth, and oxide thicknesses. (Put the calculations in an ap-pendix.) Include a graph of the expected diffusion profile. (Can be from the diffusion ex-cel calculator.)

b. Standard Clean – Don’t summarize. Simply state that the standard clean was identical to that done prior to the field oxidation and refer the reader to section 2-b.

c. Diffusion deposition and drive – Refer the reader to section 4-c, but also describe any dif-ference between the PMOS diffusion process and the pwell diffusion process.

d. Results – List your measured oxide thickness. Include the measured sheet resistance (both 4PP and TLM 2). Include the profile measured by SIMS. Describe any problems / anomalies encountered during the diffusion.

7. Lithography for NMOS source and draina. Describe the purpose of the NMOS lithographyb. Refer the reader to the lithography description in Sec. 3-b.c. Results – Include photographs. Describe any problems / anomalies encountered.

8. Phosphorus diffusion for NMOS source and draina. Describe the purpose of the NMOS diffusion and the design goals. Include predicted sur-

face concentration, junction depth, and oxide thicknesses. (Put the calculations in an ap-pendix.) Include a graph of the expected profile. (Could put it together with the pwell graph. Can be from the diffusion excel calculator).

b. Standard Clean – Refer the reader to the description in section 2-b.c. Diffusion deposition and drive – Summarize the basic procedure for the phosphorus dif-

fusion process.d. Results – List your measured oxide thickness. Include the measured sheet resistance

(both 4PP and TLM 3). Include the profile measured by SRP. Describe any problems / anomalies encountered during the diffusion.

9. Lithography for the gatea. Describe the purpose of the gate lithographyb. Refer the reader to the description in Sec. 3-b.c. Results – Include photographs. Describe any problems / anomalies encountered.

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1. Oxidation for the gatea. Describe the purpose of the gate oxide growth and the design goals. Include predicted

oxide thicknesses (Put the calculations in an appendix.) b. Standard Clean – Refer the reader to the description in section 2-b.c. Dry oxidation – Summarize the basic procedure for the gate oxide dry oxidation process.d. Results – List your measured oxide thickness. Describe any problems / anomalies en-

countered during the oxidation.

11. Lithography for contact vias / metallizationa. Describe the purpose of the contact via lithography lithography and metallization.b. Refer the reader to the description in Sec. 3-b for the lithography. Write a summary of

the metallization process.c. Results – Include photographs. Describe any problems / anomalies encountered.

12. Lithography for contactsa. Describe the purpose of the contact lithography.b. Refer the reader to the description in Sec. 3-b for the lithography, but describe the differ-

ences in this step from previous lithography steps. Describe the etching of the aluminum to form the contacts.

c. Results – Include photographs. Include etch times. Describe any problems / anomalies encountered.

SimulationsInclude SUPREM simulations for your process. There should be a full 2-D simulation for an NMOS/PMOS pair, showing expected cross-sectional view of the structure. Also, include 1-D simulations for the NMOS/PWELL and PMOS diffusions, including extracted junction depths, oxide thickness, and sheet resistances. Discuss these results in comparison to your hand calcula-tions and actual measurements taken in the lab.

TestingSummaryWrite a summary of the testing for your group. Include commentary about the problems you en-countered, non-working devices, or unusual results.

Results

1. TLM results. This is the one item where can get some concrete results, since everyone obtain good ohmic contacts to the TLM patterns before re-processing. Include the values for RS, RC, LT, and ρc for each TLM. Include at least one graph of R vs. L.

2. Transistor I-V characteristics. (Be sure to indicate which devices the curves came from and the measurement parameters used.

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3. Transistor parameters from one die. Probably best put into the form of a table. Calculate the µCox for the NMOS and PMOS devices.

4. C-V curves. Determine Cox from the curves. Compare the measured value of Cox with the measured value the gate oxide.

5. Wafer map. Include the data from your wafer map. Discuss variations seen. Discuss any anomalies.

6. Include any additional measurements that you completed.

Appendices

1. Put all of the detailed calculation one appendix and then quote the results in the main body of the report. Be sure to label the different calculations so that the reader can easily find the rele-vant equations.

2. Attach a completed process traveler.

Comments

1. Use the template to structure your report, if you’d like. If you have already written most of your report, then keep it as is, but use the template to make sure that you’ve included every-thing. If you use the template, use the headings only – all the text should be removed and re-placed with your own writings.

2. You may find that you don’t have some of the data. (Never obtained or lost in the interim.) Simply state that you don’t have the data in those cases. You won’t be penalized, unless there is a lot of missing information.

3. You can steal figures from the lab notes and class notes to use in your report – you have my permission. For example, you might want to include some of the little pictures from the process traveler page at each step in the process to help show what it happening.

4. Put some effort into the esthetics of the report. e. Number the pages.f. Use your best English. (Usually one person does the initial draft and everyone else helps

edit.)g. Write succinctly.h. Be consistent with fonts and headings and adjust the margins and spacings so that things

are neatly arranged. i. Learn how to do superscripts and subscripts in your word processor. j. It is not necessary to typeset the equations, but it certainly looks nicer if you do.

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k. If you use tables, adjust the cell size and align the rows and columns so that the table looks “nice”.

l. When making graphs, label the axes (include units!) and size the graph to fit in with the rest of the report.

m. Tables and graphs should always have titles (Table x, Figure y) and captions.

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