Method and device for transferring wafers

An assembly comprising a cassette housing containing a wafer rack and a device for transferring wafers from and to cassettes, the device comprising:

• a lock chamber having a first opening in a first wall, wherein the first opening is configured to engage with a cassette housing to receive cassettes and a second opening in a second wall opposite the first wall, wherein the second opening is configured for moving the wafers to a treatment device, wherein the first and second openings are directly opposite to each other,
• at least one first closure device configured to close said first opening, wherein the first closure device is configured to receive a cover of said cassette housing,
• a gas feed and a gas discharge provided in said lock chamber,
• a second closure device provided separate from said first closure device and configured to close said second opening, wherein said first and second closure devices are adjacent and parallel to each other.

A method for transferring wafers from and to cassettes in a lock chamber having a first opening in a first wall and a second opening in a second wall directly opposite the first wall, a first closure device for the first opening and a second closure device for the second opening, comprising:

• placing the cassette against the lock chamber such that a cover of the cassette is coincident with the first closure device for the first opening of said lock chamber;
• releasing the cover of the cassette onto said first closure device of the lock chamber;
• moving the first closure device with the cover into the lock chamber, wherein during moving the cover of said cassette the second opening is closed;
• feeding purging gas through said lock chamber;
• and
• opening of said second opening by moving said second closure device in a direction parallel to said second opening, wherein said cassette remains stationary relative to said lock chamber during opening of said cassette, and wherein said first and second closure devices move independently from each other.