Fabrication Process Lithography l Resist coating soft bake

Fabrication Process Lithography l Resist coating + soft bake l Exposure l Post-exposure bake + development Etching l Silicon etch l Oxide Etch Post processing l Dicing l Substrate thinning l Cleaving © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 1: Bare SOI wafer Layer structure l 205 Top Si layer l 400 nm Buried Oxide Wafer size l 8” (200 mm) 205 nm Si 400 nm Si. O 2 Si-substrate © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 2: Photoresist Coating Resist l Shipley UV 3 l 800 nm thick Photoresist © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 3: Soft baking of resist Photoresist © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 4: Antireflective coating AR coating l l No standing waves in resist during lithography AR-coating 40 nm of NFC © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 5: Illumination Deep UV Lithography l Wavelength = 248 nm l NA = 0. 63 l Dose = 10 -40 m. J l Reduction = 4 X © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 6: Post-exposure bake © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 7: Development © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 8: Silicon etch Etch properties l TCP 9400 PTX n ICP-RIE n Low pressure /high density l Cl 2/HBr/He/O 2 chemistry l Two-step n break-through n main etch © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 9: Oxide Etch properties l l Exelan n Dual frequency n Medium pressure /medium density CF 4/CHF 3 chemistry © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 10: Resist strip © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 11: Protective Resist Layer Substrate thinning = dangerous 1 -3 m resist cover Wafer is diced into 3 x 3 cm 2 dies for substrate thinning © intec 2002 750 m http: //www. intec. rug. ac. be/groupsites/opto

Step 12: Glue on glass plate Glue = Bee’s wax l Heated to ± 130°C Bee’s wax Glass plate © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto

Step 13: Substrate thinning Mechanical grinding l Alumina powder l 5 -8 hours l Remove 500 m 250 m Bee’s wax Glass plate © intec 2002 http: //www. intec. rug. ac. be/groupsites/opto