Patent ID: 8343693

Claim:
A focus test mask comprising a test pattern which is to be projected onto an object via a projection optical system, wherein the test pattern includes: a first light shielding portion which extends in a line form in a first direction and which shields a light; a first phase shift portion which is provided on one side of the first light shielding portion in relation to a second direction perpendicular to the first direction, which extends in a line form in the first direction, which is formed to have a line width in relation to the second direction narrower than a line width of the first light shielding portion, and which changes a phase of the light transmitted therethrough; a first transmitting portion which is provided on the other side of the first light shielding portion in relation to the second direction, which extends in a line form in the first direction, which is formed to have a line width in relation to the second direction narrower than the line width of the first light shielding portion, and through which the light is transmitted; and a second phase shift portion which is provided on a side of the first transmitting portion opposite to the first light shielding portion in relation to the second direction, which is formed to have a line width in relation to the second direction wider than the first transmitting portion, and which changes the phase of the light transmitted therethrough.