SiO2 (1 um thick) 10 um Si wafer (300 um thick) (1) Assume that you begin with a silicon wafer with SiO2 deposited on bo

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Sio2 1 Um Thick 10 Um Si Wafer 300 Um Thick 1 Assume That You Begin With A Silicon Wafer With Sio2 Deposited On Bo 1 (72.47 KiB) Viewed 14 times

SiO2 (1 um thick) 10 um Si wafer (300 um thick) (1) Assume that you begin with a silicon wafer with SiO2 deposited on both sides. Prior to etching SiO2, a photoresist pattern needs to be defined. Which photoresist will be better for this application, positive PR or negative PR? For the photoresist of your choice, what mask polarity do you choose, clear field or dark field? Justify your choices. (4) (2) If SiO2 is etched in BOE (6:1) and the oxide is a thermally grown oxide, what is the predicted etch time? Draw the etch profile below. (5) PR SiO2 Si 10 um = SiO2 Before etching After etching (3) Etching time control is essential in this case. Explain how you can determine if the etching has been completed. (3) (4) If the sample is over-etched (20 min) what will the etch profile look like? Draw the etch profile below. (3) (5) If RIE is used instead of BOE in (2), what will the etch profile look like? Draw the side view below. (3)