Wafer dryer apparatus and method

A method of drying semiconductor wafers comprising:

• moving one or more semiconductor wafers from a first wafer carrier in a of liquid and out of the bath of liquid and to a second wafer carrier that is out of the bath of liquid and spaced from the first wafer carrier;
• flowing a mixture of nitrogen (N2) and isopropyl alcohol (IPA) onto the one or more wafers as the one or more wafers are moved out of the bath of liquid such that the surfaces of the one or more wafers are dried at least in part by a surface tension gradient between the IPA and the liquid in the bath;
• drying the first wafer carrier;
• shielding the one or more wafers on the second wafer carrier from mist or droplets arising from drying the first wafer carrier;
• and
• returning the one or more wafers from the second wafer carrier to the first wafer carrier following drying of the first wafer carrier.

An apparatus for drying semiconductor wafers comprising:

• a wafer receiving tank comprising a tank body which defines an interior tank chamber comprising upper and lower tank chamber portions, a top portion with a wafer carrier receiving opening communicating with the tank chamber and sized for receiving a first wafer carrier with one or more semiconductor wafers thereon, and a bottom portion, the tank further comprising a liquid inlet communicating with the lower tank chamber portion and for coupling to a source of cleaning liquid, the tank chamber having at least one overflow outlet at the upper tank chamber portion such that liquid from the liquid inlet flows upwardly to the at least one overflow outlet, the tank having a drain outlet communicating with the lower tank chamber portion;
• a wafer carrier lifter positioned in the tank chamber and positioned to receive a first wafer carrier with one or more semiconductor wafers thereon through the wafer carrier receiving opening, a first actuator coupled to the wafer carrier lifter and operable to lift and lower the wafer carrier lifter and the first wafer carrier received by the wafer carrier lifter and also to lift the one or more semiconductor wafers from a position on the first wafer carrier from a first lower wafer carrier position on the first wafer carrier to a second elevated wafer carrier transfer position above the first wafer carrier, wherein when in the first lower wafer carrier position the first wafer carrier and the one or more semiconductor wafers thereon are submerged in liquid in the interior tank chamber, the first actuator also being operable to lift the one or more semiconductor wafers thereon from the liquid in the lower chamber at a controlled wafer lifting rate;
• a wafer drying chamber coupled to the tank and mounted for movement from a first drying chamber position overlaying and covering the wafer carrier receiving opening to a second drying chamber position that is offset from the wafer carrier receiving opening and from the second drying chamber position to the first drying chamber position, a second actuator coupled to the wafer drying chamber and operable to move the wafer drying chamber from the first drying chamber position to the second drying chamber position and from the second drying chamber position to the first drying chamber position, a second wafer carrier positioned in the wafer drying chamber, the second wafer carrier receiving the one or more wafers from the first wafer carrier that have been lifted to the second elevated wafer carrier transfer position, the wafer drying chamber comprising a first gas inlet for coupling to a source of blended isopropyl alcohol and nitrogen (IPA/N2) so as to provide IPA/N2 to the surfaces of the wafers as the wafers are lifted out of the liquid in the interior tank chamber by the wafer carrier lifter toward the second elevated wafer carrier transfer position, the IPA in the IPA/N2 blend at least partially drying the surfaces of the wafers by surface tension gradient drying as the wafers are lifted out of the liquid;
• a valve coupled to the tank chamber and operable to drain the liquid from the tank through the drain at a rate that the IPA/N2 at least partially dries the surfaces of the first wafer carrier and wafer carrier lifter as the tank is drained to expose the first wafer carrier and wafer carrier lifter;
• the second actuator being operable to move the wafer drying chamber and the second wafer carrier with the received one or more wafers from the first drying chamber position to the second drying chamber position and from the second drying chamber position to the first drying chamber position;
• and
• at least one gas applicator positioned in the tank chamber for coupling to a source of N2 to deliver N2 to the first wafer carrier to continue drying the first wafer carrier and wafer lifter following exposure of the first wafer carrier and wafer lifter from liquid in the lower tank chamber portion and with the wafer drying chamber and one or more wafers from the first wafer carrier on the second wafer carrier in the second drying chamber position.

A method of drying semiconductor wafers comprising:

• moving one or more semiconductor wafers from a first wafer carrier in a bath of liquid in a tank and out of the bath of liquid and to a second wafer carrier that is out of the bath of liquid and spaced from the first wafer carrier;
• flowing a mixture of nitrogen (N2) and isopropyl alcohol (IPA) onto the one or more wafers as the one or more wafers are moved out of the bath of liquid such that the surfaces of the one or more wafers are dried at least in part by a surface tension gradient between the IPA and the liquid in the bath;
• draining liquid from the tank to expose the first wafer carrier in the tank;
• drying the first wafer carrier;
• shielding the one or more wafers on the second wafer carrier from mist or droplets arising from drying the first wafer carrier in the tank;
• and
• returning the one or more wafers from the second wafer carrier to the first wafer carrier following drying of the first wafer carrier.