a substrate 520 after the substrate transit 330 positions a substrate 520 within the substrate carrier assembly 501 the alignment pick ups 510 engage the substrate 520 with a v shaped notch 511 fig5 b that centers the substrate 520 axially within the substrate carrier 501 and aligns it within the plane defined by the notches of the three pickups once the substrate 520 has been 34 pre aligned 34 primary pick ups 515 engage the substrate 520 and the alignment pick ups 510 rotate out of the way shallow recesses 516 in the primary pick ups 515 fig5 c positively hold the substrate 520 with minimal overlap of and interference with the substrate face during processing furthermore the pick ups 510 515 have a degree of compliance to compensate for thermal expansion of substrates 520 after substrate 520 has been processed substrate transit 340 positions the end effector 341 within the center hole of the substrate 520 the primary pick ups 515 retract from the substrate 520 and the end effector engages the center hole and removes the substrate 520 by retracting until the substrate 520 is above the first available cassette slot the elevator 321 or 323 elevates the cassette until the substrate 520 is situated within the slot the transit 340 then releases the substrate 520 and fully retracts the elevator 321 or 323 then descends to the down position until another substrate 520 is positioned above it fig2 4 6 and 7 are referred to in the following discussion of the main chamber transport system as shown in fig6 carriage 610 supports substrate carrier assembly 501 and has a bearing set that allows motion.