| abstract |
The present invention generally provides an apparatus and a method for scanning a substrate in a processing system. A transmitter unit and a receiver unit are disposed on a processing system and cooperate to transmit and detect energy, respectively. The transmitter unit is positioned to transmit a signal onto the substrate surface moving between vacuum chambers, one of which is preferably a transfer chamber of a cluster tool. Features disposed on the substrate surface, which may include particles, devices, alphanumeric characters, the substrate edges, notches, etc., cause a scattering or reflection of a portion of the signal. The receiver unit is disposed to collect the scattered/reflected portion of the signal and direct the same to a processing unit. Preferably, the transmitter unit comprises a laser source and the receiver unit comprises a charged-coupled device (CCD). Preferably, the invention is integrally positioned in a processing system to allow substrate inspection during normal operation and provide real-time information. |