06208407 is referenced by 499 patents and cites 8 patents.

In a lithographic projection apparatus, a time-saving height measurement method is used. While in a projection station (

105,108,111

) the pattern of a mask (

129

) is projected on the fields of a first substrate (

120

), the height of the fields of a second substrate (

121

) is measured in a measuring station (

133

). In the measuring station, the height of the substrate fields and the height of the substrate holder (

113

) are measured by a first height sensor (

150

) and a second height sensor (

160

), respectively, and the value of the height of the substrate holder associated with the ideal height of the substrate field is determined for each substrate field. In the projection station, only the height of the substrate holder (

111

) is controlled by a third height sensor (

180

). The second and third height sensors are preferably part of a composite XY interferometer system extended with a Z measuring axis.

Title
Method and apparatus for repetitively projecting a mask pattern on a substrate, using a time-saving height measurement
Application Number
9/114748
Publication Number
6208407 (B1)
Application Date
July 13, 1998
Publication Date
March 27, 2001
Inventor
Erik R Loopstra
Heeze
US
Agent
Pillsbury Madison & Sutro
US
Assignee
ASM Lithography
US
IPC
G03B 27/42
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