Design of a Quartz Boat for High Temperature Wafer Processing
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Standard boats presently used in high temperature wafer processing, as for arsenic diffusion in a closed capsule (in the range of 1100-1200Œ), may cause severe damage at the periphery of the wafer which, in turn, will reduce the final test yields. Theoretically, a standard quartz boat secures the wafer at four contact points, depicted as A, B, C and D in the above schematic side view, but practically it secures on two points only due to an undesired misadjustment, such as a tilt of the boat, for example. It has been shown that in this range, due to the difference between the temperature coefficients of silicon and quartz and to the internal stresses in the silicon wafers, the latter may warp and then become blocked at contact points A and C.