Abstract: A substrate carrier including an enclosure to hold substrates. The enclosure includes walls configured to surround the substrates, where the walls include a front panel, a back panel parallel to the front panel, and two side panels perpendicular to the front and back panels and to the substrates. The enclosure further includes a top opening, and a bottom opening. The substrate carrier further includes an adjustable clamping mechanism on each of the two side panels. The adjustable clamping mechanism includes a plurality of pairs of jaws that are each configured to clamp one of the substrates, where the jaws in each pair face one another with an intervening gap that is configured to accommodate a substrate. The substrate carrier further includes a locking mechanism on at least one of the two side panels, configured to lock positions of the plurality of pairs of jaws to fix positions of the substrates.