| 摘要 |
<p>PURPOSE:To eliminate variations in film thickness between wafers by dividing the slits, for letting gas flow in a wafer holder for film formation, in the direction of length into smaller slits, shifting the positions of the divided slits every other slit in the direction of circumference, and forming them so that the ends of the adjacent smaller slits will be positioned on the circumference of the same circle. CONSTITUTION:A wafer holder 31 for film formation consists of a basket 311, a basket cover 312 and two substrate positioning frames 113. Slits for letting gas flow are formed on the basket 311. The slits are divided into a plurality of smaller slits 311a-1, 311a-2, and the smaller slits are positioned on both sides of each line at 45 deg. from the center line of the basket. Their positions are shifted in the direction of circumference every other smaller slit by an amount equal to or larger than the width of each smaller slit. The ends of the adjacent smaller slits are on the circumference of the same circle. Slits for letting gas flow are also formed on the basket cover 312 in the same manner. This makes constant the amount of material gas and thus eliminates variations in film thickness from one wafer to another.</p> |
