Method and apparatus for detecting aberrations in an optical system

A construction for detecting aberrations in an optical system utilized in a lithographic projection apparatus comprising:

• a radiation system for supplying a projection beam of radiation;
• a mask table for holding a mask;
• a substrate table for holding a substrate;
• and
• a projection system for projecting a pattern in the mask onto a target portion of the substrate,
• said optical system comprising at least one of the radiation system and projection system,
• said construction comprising a mask plate carrying a monitor pattern, said monitor pattern comprising a plurality of sub-resolution features disposed on said mask plate, said plurality of sub-resolution features arranged so as to form a predetermined test pattern on said substrate, said predetermined pattern being utilized to detect said aberrations,
• wherein none of said plurality of sub-resolution features are individually imaged on said substrate.

A device manufacturing method comprising the steps of:

• (a) providing a substrate that is at least partially covered by a layer of radiation-sensitive material;
• (b) providing a projection beam of radiation using a radiation system;
• (c) using patterning means to endow the projection beam with a pattern in its cross-section;
• (d) using a projection system to project the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material,
• wherein, prior to the use of an integrated device pattern in step (d), an aberration monitoring step is performed comprising the steps of:
• providing the pattern of step (C) to comprise a monitor having a plurality of sub-resolution features, where the plurality of sub-resolution features is arranged so as to form a predetermined test pattern when projected on the substrate;
• projecting the monitor onto the substrate using the projection system, and;
• analyzing the position of said predetermined test pattern and the position of the plurality of sub-resolution features in the monitor so as to determine if there is an aberration in at least one of the radiation system and projection system,
• wherein none of said plurality of sub-resolution features are individually imaged on said substrate.