Abstract:
A lithographic apparatus including a moveable object (WT) and a displacement measuring system arranged to determine a position quantity of the moveable object. The displacement measuring system includes an encoder (BC) and a grid structure. One of the encoder and the grid structure is connected to the moveable object. The grid structure includes a high precision grid portion (HG) and a low precision grid portion (LG). The encoder is arranged to cooperate with the high precision grid portion to determine the position quantity relative to the grid structure with a high precision. The encoder is arranged to cooperate with the low precision grid portion to determine the position quantity relative to the grid structure with a low precision.
Abstract:
The invention relates to a vibration isolator, comprising: a base; a coupling element to be coupled to a vibration sensitive object; a decoupling mass; a first vibration isolator pan arranged between the base and the decoupling mass; and a second vibration isolator part arranged between the decoupling mass and the coupling element, and wherein at least one of the first and second vibration isolator part comprises a pneumatic isolator.
Abstract:
A lithographic apparatus including a moveable object (WT) and a displacement measuring system arranged to determine a position quantity of the moveable object. The displacement measuring system includes an encoder (BC) and a grid structure. One of the encoder and the grid structure is connected to the moveable object. The grid structure includes a high precision grid portion (HG) and a low precision grid portion (LG). The encoder is arranged to cooperate with the high precision grid portion to determine the position quantity relative to the grid structure with a high precision. The encoder is arranged to cooperate with the low precision grid portion to determine the position quantity relative to the grid structure with a low precision.
Abstract:
The invention relates to a vibration isolator, comprising: a base; a coupling element to be coupled to a vibration sensitive object; a decoupling mass; a first vibration isolator part arranged between the base and the decoupling mass; and a second vibration isolator part arranged between the decoupling mass and the coupling element, and wherein at least one of the first and second vibration isolator part comprises a pneumatic isolator.
Abstract:
A measurement system for a lithographic apparatus includes a sub-frame compliantly mounted on a reference frame. A measurement device, e.g. an alignment sensor, is mounted on the sub-frame. Soft mounting of the sub-frame isolates the alignment sensor from high-frequency disturbances, e.g. acoustic noise, by acting as a low-pass filter with a cut-off frequency, e.g. in the range of from 100 to 200 Hz.