Apparatus and methods for reducing damage to substrates during megasonic cleaning processes

An apparatus for cleaning a thin, flat substrate, the apparatus comprising:

• a support supporting the substrate in a generally horizontal orientation;
• means for applying a thin film of liquid to a first surface of the substrate;
• and
• a sonic energy transmitter;
• wherein
• the transmitter transmits sonic energy to the substrate first surface, and the transmitter attenuates the sonic energy to reduce the number of sonic waves that strike the substrate at or near a ninety-degree angle.

Apparatus for cleaning a thin article having at least a first substantially planar surface, the apparatus comprising:

• a support for the article;
• a source of fluid for applying fluid to the first surface;
• a transmitter configured to vibrate so as to transmit sonic energy through the fluid to the first surface to loosen particles on the first surface;
• a transducer for vibrating the transmitter;
• and
• a wall with an opening therein through which gas is introduced to flow in contact with the transducer;
• wherein
• the transmitter attenuates the sonic energy to reduce the number of sonic waves that strike the article at or near a ninety-degree angle.

A method of cleaning a thin, flat substrate, the method comprising the steps of:

• supporting a thin, flat substrate, the substrate having at least a first surface;
• applying a liquid to the first surface;
• providing at least a first source of sonic energy;
• providing at least a first sonic energy transmitter spaced from the substrate but in contact with the liquid;
• energizing the first source of sonic energy, thereby applying sonic energy to the transmitter;
• transmitting sonic energy through the transmitter to the substrate first surface through the liquid;
• and
• attenuating the sonic energy to reduce the number of sonic waves that strike the substrate at or near a ninety-degree angle.