US 6,582,221 B1 · Wafer boat and method for treatment of substrates

Abstract

A substrate holder for vertical furnaces is configured to support substrates in slots at inner portions of the substrates, rather than solely at the edges. The holder allows sufficient clearance above substantially the entire front face of the substrate that a substrate deflection or bow, induced by thermal stresses during loading and unloading of the substrate holder into and out of the furnace, can be accommodated without the substrate touching the support members of the substrate holder. A relationship is established such that, for given loading/unloading temperatures, a minimum amount of free space in the wafer slots is provided to avoid substrate scratching. Conversely, for a given amount of free space in the wafer slots, the relationship provides maximum loading and/or unloading temperatures to avoid scratching.

Claims14

Dependent claims

A method for thermal treatment of substrates, comprising:

providing a holder comprising a plurality of accommodations in a vertically spaced apart relationship, each accommodation capable of at least partially horizontally supporting a substrate at an inner area spaced more than 20 mm from the substrate edge, and each accommodation having a free height (h);
placing a plurality of substrates in the holder;
loading the substrate holder with the plurality of substrates into a vertical furnace at a loading temperature (Tload);
heating the furnace to a thermal treatment temperature;
performing the thermal treatment at the thermal treatment temperature;
cooling down the furnace after performing the thermal treatment to an unloading temperature Tunload;
unloading the substrate holder from the furnace after cooling down;
and
selecting one of (h) and (Tunload) and determining the other of (h) and (Tunload) according to a predetermined relationship between the free height and the unloading temperature in which scratching of the substrates is avoided.

6 more elements

Dependencies are inferred from the claim text.

Wafer boat and method for treatment of substrates

Life of this patent

Wafer boat and method for treatment of substrates

Life of this patent

Abstract

Claims14