Device manufacturing method and lithographic apparatus

A lithographic apparatus including a phase adjuster constructed and arranged to adjust a phase of an electric field of an optical radiation beam traversing a projection system of the lithographic apparatus, and a controller constructed and arranged to apply a spatial phase distribution to an optical wave traversing the phase adjuster, the controller including a computer program containing machine-readable instructions arranged to

• adjust a phase of zeroth order diffracted radiation to substantially match a phase of first first-order diffracted radiation, or vice versa, using the phase adjuster, and
• adjust a phase of second first-order diffracted radiation to substantially match the phase of the first first-order diffracted radiation plus 180° using the phase adjuster, wherein
• a mask pattern is illuminated with a beam of radiation to provide the zeroth order diffracted radiation, the first first-order diffracted radiation and the second first-order diffracted radiation emanating from the mask pattern and the zeroth and first-order diffracted radiation traverse the optical phase adjuster, and
• the mask pattern is imaged on a substrate using the projection system.

A device manufacturing method of projecting a pattern of a patterning device onto a substrate, the method comprising:

• emanating a zeroth order diffracted radiation, first first-order diffracted radiation and second first-order diffracted radiation from the pattern of the patterning device;
• imaging the pattern onto a substrate using a projection system;
• and
• adjusting phase of at least part of the diffracted radiation using an optical phase adjuster, wherein the zeroth and first-order diffracted radiation traverses the optical phase adjuster, the adjusting including:
• adjusting phase so that the phase of the zeroth order diffracted radiation substantially matches the phase of the first first-order diffracted radiation, and
• adjusting phase so that the phase of the second first-order diffracted radiation substantially matches the phase of the first first-order diffracted radiation plus 180°.