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Silicon Wafer Oxidation Boat

IP.com Disclosure Number: IPCOM000047582D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Gilmartin, PA: AUTHOR [+2]

Abstract

An improved silicon wafer oxidation boat is shown in Figs. 1 and 2, wherein Fig. 2 is the end view from the inlet side of Fig. 1. Mixing baffles and a convection baffle are added to a standard open-rail oxidation boat. There is an increased silicon dioxide formation uniformity obtained with this boat compared with the boat without baffles. Nonuniform thermal silicon dioxide thicknesses were observed in 82.5 mm. wafers oxidized in large bore (132 mm.) furnace tubes. In this system oxygen (O2) carrier gas is bubbled through 95 C water at 1 liters/minute to supply water (H2O) vapor. Total flow into the furnace tube is approximately 8 liters/minute.

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Silicon Wafer Oxidation Boat

An improved silicon wafer oxidation boat is shown in Figs. 1 and 2, wherein Fig. 2 is the end view from the inlet side of Fig. 1. Mixing baffles and a convection baffle are added to a standard open-rail oxidation boat. There is an increased silicon dioxide formation uniformity obtained with this boat compared with the boat without baffles. Nonuniform thermal silicon dioxide thicknesses were observed in 82.5 mm. wafers oxidized in large bore (132 mm.) furnace tubes. In this system oxygen (O2) carrier gas is bubbled through 95 C water at 1 liters/minute to supply water (H2O) vapor. Total flow into the furnace tube is approximately 8 liters/minute. Silica mixing baffles 10 and convection baffle 11 were attached to a standard oxidation boat 12 to promote gas mixing between O2 and H2O portions of the cycle and to prevent convection cells over the wafers. The baffles 10 and 11 are circular 110 mm. in diameter for a 130 mm. inner diameter process tube. Four one-centimeter holes 14 are located in each of the two mixing baffles. The pattern is rotated 45OE so that the holes 14 do not align. No holes are present in the convection baffle. A comparison was made between wafers oxidized in a standard boat and in a baffled boat. The oxidation was performed at 925OEC using a cycle of 7 min. O2, 53 min. H2O vapor, 10 min. O2 . The results were: Thicknesses were measured at 19 points on each wafer. Averages are over all 19 points. Sigma (s) is the stan...