EE 143 MICROFABRICATION TECHNOLOGY SPRING 2010 C Nguyen LAB REPORT 1 Due Friday Apr 23 2010 7 00 p m in the EE 143 homework box in 240 Cory Table of Contents I Profiles Layout 14 Points II Process Procedures 20 points III Calculations 36 Points IV Questions 30 Points V Bonus Questions 10 Points Total Points 110 possible graded out of 100 Please be sure to include the requirement signature regarding academic honesty All lab group members should print out this page the last page after the report template sign on the attached form and include it with your Lab Report Thank you REPORTS MUST BE WORD PROCESSED EXCEPT FOR SKETCHES AND HAND WRITTEN CALCULATIONS Each group of students will submit one joint report There will be a 20 PAGE max limit on the report Please use the report template Profiles Layout and Calculations do not count towards this page limit FOLLOW THE ATTACHED TEMPLATE FORMAT FOR THE REPORT STUDENTS NOT FOLLOWING THIS FORMAT WILL BE DEDUCTED 10 PER SECTION DEVIATING FROM TEMPLATE When possible be concise and use structured bullet points EE 143 MICROFABRICATION TECHNOLOGY SPRING 2010 C Nguyen I Profiles Layout 14 Points The process flow W1 Staring Wafer W2 Field Oxidation W3 ACTV Photolithography and Etch W4 Gate Oxidation W5a Anchor Opening Photolithography for MEMS W5b Polysilicon CVD W6 POLY Lithography and Etch Source Drain Clear W7a Spin on Glass Source Drain Pre diffusion W7b Source Drain Drive in Intermediate Oxidation W8 CONT Photolithography and Etch W9 Aluminum Evaporation W10 METL Photolithography Etch W11 RELE MEMS Comb drive Structure Release Photolithography Etch A A Draw cross sectional profiles AA of a MOSFET test structure 9 after each of the steps EE 143 MICROFABRICATION TECHNOLOGY SPRING 2010 C Nguyen Indicate all layers Label each feature and indicate thicknesses make roughly proportional sketches Illustrate and describe important details non planar interfaces from thermal oxidation isotropic etch profiles point source Al evaporation thermal oxidation growth These drawings should have significantly more detail than those on the lab manual website See the diagram below for the exact cross sections in question 5 Points B Draw top views of the same thin oxide MOSFET test structure 9 after each of the four photolithography steps ACTV POLY CONT METL 4 Points C Draw cross sectional profiles of the comb drive MEMS test structure 22 after each of the 12 major processing steps in the same fashion that you did for the MOSFET See the diagram below for the exact cross sections in question The line runs through the anchor hole of the polystructure 5 Points A A II Process Procedures 20 Points Refer to Template at the back of the Report A Describe monitoring measurements that were done during processing Film color Line Width Thickness EE 143 MICROFABRICATION TECHNOLOGY SPRING 2010 C Nguyen Resistivity Vernier Determine whether each layer was overetched or underetched Did you purposely over underetch Why Describe how the verniers are used to measure misalignment Using diagrams may help Were any layers misaligned intentionally For each pair of verniers ACTV POLY ACTV CONT POLY CONT CONT METL POLY RELE describe how far the marks may be misaligned in terms of device function 6 Points B List and concisely describe the possible problems that could have occurred during the batch fabrication steps W2 Field Oxidation W4 Gate Oxidation W5 Poly Deposition W7a Source Drain Prediffusion W7b Drive In Intermediate Oxidation W9 Aluminum Evaporation W10 Sintering What were the sources of the problems and how could you avoid them How do you expect these deviations to affect the performance function and cross section of the device List the types of monitoring measurements from Part A taken during each step 7 Points C Other than the problems that occurred during the batch sessions what were the particular problems or deviations from other groups that could occur in YOUR wafer Specifically these are the steps where all wafers were run in individually W3 ACTV Photolithography W5 ANCR anchor opening for MEMS Photolithography W6 POLY Photolithography W7 SOG Deposition SOG Strip W8 CONT Photolithography W10 METL Photolithography W11 RELE protect MOSFET for MEMS release Photolithography What were the causes and how were the problems overcome How would these affect device performance Include any illustrations that would be helpful List the types of measurements from Part A taken during each step 7 Points III Calculations 36 Points Refer to Report Template at Back of Report EE 143 MICROFABRICATION TECHNOLOGY SPRING 2010 C Nguyen Fill the template table with the following parameters from your own wafer 3 points a Film thickness each layer b Sheet Resistance after ion implantation and S D formation c over underetch measured photoresist from theoretical each layer Calculate the parameters asked for in the following questions list both the theoretical values and the empirical values when applicable We would like to see that you understand what processing abnormalities may have led to a discrepancy between the two Neatly write up and annotate all calculations and attach in appendix Points will be deducted if we cannot understand what you wrote 1 Theoretical and experimental thicknesses of field oxide gate and intermediate oxides Include orientation dependence of oxidation rate but not impurity dependence 9 points 2 Junction depths after pre diffusion and drive in theoretical assume only phosphorous doping with surface concentration limited by solid solubility You must consider the effect of the initial ion implantation For pre deposition you may use the box approximation but for drive in you must use the half gaussian calculation Why is this 10 points 3 Final surface concentrations of dopants as determined from Irvin s curves using sheet resistance measurements made in lab 2 points 4 Plot or sketch the change of dopant profile from the silicon surface through the source drain after each thermal step Field Oxidation Gate Oxidation Poly Deposition Pre Deposition Drive In Intermediate Oxidation Sintering Quantitatively label significant points such as Peak concentration Peak Width Junction Depth Show movement of the Silicon Silicon Dioxide interface and qualitatively show non ideal effects such as dopant redistribution during oxidation 11 points 5 Lateral diffusion under the MOSFET gates estimation Theoretical 2 points You may estimate Justify 6 List an estimate of the Young s modulus Poisson ratio
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