Apparatus for measuring an exposure intensity on a wafer
View Patent ↗An apparatus for measuring an exposure intensity on a wafer is disclosed. According to one aspect, an apparatus for measuring an exposure intensity on a wafer includes an exposure device for generating a radiation having a predetermined wavelength. Further, the apparatus includes a mask at a first predetermined distance from the exposure device for patterned exposure of a wafer A detection device detects the exposure intensity at a second predetermined distance from the exposure device. A compensation device can be moved into the beam path between the exposure device and the detection device for the purpose of influencing the beam path.
1. Apparatus for measuring an exposure intensity on a wafer having:
(a) an exposure device for generating a radiation having a predetermined wavelength;
(b) a mask at a first predetermined distance from the exposure device for patterned exposure of a wafer;
(c) a detection device for detecting the exposure intensity at a second predetermined distance from the exposure device; and
(d) a compensation device which can be moved into the beam path between the exposure device and the detection device for the purpose of influencing the beam path, wherein the compensation device is made of fluorine-doped quartz glass from which hard pellicles are formed.
2. Apparatus according to claim 1 wherein the compensation device has a thickness of less than 1 mm, preferably 0.8 mm.
3. Apparatus according to claim 1 , wherein the radiation of the exposure device has a wavelength of less than 200 nm, preferably less than 160 nm.
4. Apparatus according to claim 1 , wherein the movable compensation device is fixed in a movable mount that can be precisely determined in terms of the distance in the exposure direction, and/or in terms of the angle with respect to the exposure direction and/or with respect to the mask, and can be set independently of the mask.
5. Apparatus according to claim 4 , wherein the mount of the movable compensation device has a device for generating predetermined mechanical stresses in the movable compensation device.
6. Apparatus according to claim 1 , wherein the movable compensation device is arranged between the detection device and the mask.
7. Apparatus according to claim 1 , wherein the exposure device has a light source, preferably a laser.
8. Apparatus according to claim 1 , wherein the movable compensation device is arranged permanently in the beam path.
9. Apparatus according to claim 1 , wherein provision is made of an imaging optical arrangement having at least one lens for generating a predetermined beam path between the mask and the detection device, the imaging optical arrangement being optimized for a mask with a hard pellicle.
10. Apparatus according to claim 1 , wherein the detection device has a CCD camera.
11. Method for measuring an exposure intensity on a wafer, having the following steps:
(a) generating a radiation having a predetermined wavelength by means of an exposure device.
(b) patterned exposing a detection device instead of a wafer by means of a mask at a first predetermined distance from the exposure device.
(c) detecting the exposure intensity by means of the detection device at a second predetermined distance from the exposure device; and
(d) influencing of the beam path by means of a compensation device that can be moved into the beam path between the exposure device and the detection device if a mask without a hard pellicle is measured, wherein the compensation device is made of fluorine-doped quartz glass from which hard pellicles are formed.