Abstract: A clamp for fixturing a substrate when forming and thermally processing upon the substrate a thermally flowable layer. The clamp comprises a backing member having a top member connected through a first mechanical means to the backing member. The backing member and the top member are sized such that a substrate may be clamped between the backing member and the top member. A portion of the top member overlaps the substrate and leaves exposed a first portion of the substrate when the substrate is clamped between the backing member and the top member. The clamp also comprises a shroud connected through a second mechanical means to the backing member, where a portion of the shroud overlaps the top member. The shroud leaves exposed a second portion of the substrate which is smaller than and contained within the first portion of the substrate. The shroud is removable from the backing member while the substrate remains clamped between the backing member and the top member.