MEM 417_LabIII_Wet Etching (Repaired)

MEM 417_LabIII_Wet Etching (Repaired) - DREXEL UNI VERSI TY...

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Unformatted text preview: DREXEL UNI VERSI TY MEM 417 - MI CROFABRI CATI ON FALL 2008 LAB # 3 Wet Etching | Lakir Patel Lab # 3, Wet Etching was divided into three separate parts as follows: I) Chrome Etching I I) Buffered Oxide Etching (BOE) I I I) KOH Etching of Silicon Procedures: Chrome Etching: o Materials: A 4 X 4 in glass plate was used with a thin layer of Chromium and a coated positive photo resist (Shipley 1827). Developer solution was DI (1:3). A chrome etchant was also used. o Just like Photolithography Lab, A mask was coated with photo resist at a rate of 3000RPM for 30 seconds. This sample was soft baked for 3 minutes @ 100C. With a recommended UV dosage of 200mJ/cm^2, with a constant UV intensity @ 23.4mJ/cm^2, the exposure time was calculated to be about 9 seconds. Sample was then developed along with agitation for time duration of 30 seconds, rinsed with DI water and dried. Inspection under the microscope was performed to see if further development was needed, none did. Finally, sample was hard baked @ 100C for 3 minutes. o The sample was then etched, with agitation. Again, rinsed with DI water and dried for inspection to see if further etching was needed to achieve desired outcome. o To remove the PR from the sample, that is no longer needed, acetone was used extensively to strip PR from the sample. Then the sample was then sprayed with methanol and DI water to neutralize the acetone. Sample was then dried and inspected. Results will be discussed later. Buffered Oxide Etching (BOE): o Materials: A 3 inch (100) silicon wafer with thermally grown oxide was used. Photo resist pattern was used of Shipley 1827, from previous lab. BOE solution was created using, 40% NH4F and 49% HF, with 6:1, respectively. o To initiate Etching, the sample was hard baked @ 100C for 3 minutes. This time the sample was allowed to each without any agitation, with approximate etch rate of 0.1 m/min, approximately taking 10 minutes to reach desired depth. The sample then was DI water and dried for inspection. o To remove the PR from the sample, acetone once again was sprayed on the sample, as the strip was clearly seen washing to the bottom of the sample. To neutralize acetone, methanol and DI water were used. Inspection was performed after drying the sample....
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This note was uploaded on 11/30/2008 for the course MEM 417 taught by Professor Noh during the Fall '08 term at Drexel.

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MEM 417_LabIII_Wet Etching (Repaired) - DREXEL UNI VERSI TY...

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