| abstract |
The disclosure relates to an apparatus and anmethod for scanning a substrate in a processing systemn(40). A transmitter unit (56) and a receiver unitn(58) are disposed on a processing system and cooperatento transmit and detect energy, respectively. Thentransmitter unit is positioned to transmit a signalnonto the substrate surface (37) moving between vacuumnchambers (44), one of which is preferably a transfernchamber (42) of a cluster tool (100). Featuresndisposed on the substrate surface, which may includenparticles, devices, alphanumeric characters, thensubstrate edges, notches, etc., cause a scattering ornreflection of a portion of the signal. The receivernunit is disposed to collect the scattered/reflectednportion of the signal and direct the same to anprecessing unit (86). Preferably, the transmitternunit comprises a laser source and the receiver unitncomprises a charged-coupled device (CCD). Preferably,nthe invention is integrally positioned in a processingnsystem to allow substrate inspection during normalnoperation and provide real-time information. |