Knowing Cantilever Paddle

During processing, semiconductor wafers must usually be heated in a specialized furnace. Such furnaces typically consist of long, thin, cylindrical tubes. The wafers are positioned in the furnace and reactor in such a way that they are arranged along a plane defined by the circular cross-section of the furnace or reactor and are spaced apart at predetermined, usually equally spaced, points along the central axis of the furnace or reactor. To achieve this positioning, the wafers are typically placed on slotted holders, called wafer boats, which place the wafers in a spaced configuration aligned along the central axis.

Small boats containing batches of wafers to be processed are placed on long cantilever paddles through which tubular furnaces and reactors can be inserted and withdrawn. Such paddles typically include a flat carrier section on which one or more small boats can be placed, and a long handle, located at one end of the flat carrier section, by which the paddles can be handled. A transition portion is usually formed between the handle and the carrier portion to make them a whole. Also, the handle must extend out of the furnace or reactor so that it and the wafer boat can be manipulated.

The positioning of the wafer ship within the furnace or reactor is important because it is desirable to place the center of each wafer as close as possible to the central axis of the furnace or reactor to achieve uniform processing conditions to which the wafers are subjected. Therefore, the bending of the paddle caused by the weight of the ship carrying the wafers must be considered in the paddle design, especially since the paddle is supported at only one end, i.e., the end that protrudes from the furnace chamber. In addition to considering the paddle design resulting from the operational weight requirements, a set of clamps designed to precisely hold the extended end of the paddle in position must also be used. These clamps must be quite robust to keep the paddle in a precisely desired position while being simple to use and minimizing the possibility of damage to the paddle during clamping.

Therefore, a cantilever paddle was needed that could be used with a heavier load while remaining compatible with existing clamping systems. There was also a need for a cantilever paddle that exhibited acceptable deflection characteristics over the entire range of weight loads it could be used with.

The cantilever paddle is recommended to using recrystallized silicon carbide with a CVD SiC thin layer, which is high purity and best choice for the components in semiconductor processing.

Semicorex can provide high quality cantilever paddles and customized services according to the drawings and working environment.