Gas bearing and lithographic apparatus including such a bearing

摘要

A gas (air) bearing in a ceramic body 1 is made using a separate restriction member to define the air restriction feature. The separate member may be a metal bushing 5 in which an insert 6 is fitted, the insert 6 having an opening defining the actual restriction feature. Alternatively the separate member may be a ceramic plate 8 with restriction features machined by laser or abrasion before or after attachment to the main body.