초록 ▼

Embodiments relate to a method, optical module and auto-focusing system for wafer edge exposure. The optical module comprises a light source emitting light of a wavelength to expose a photoresist, an exposing optics and a mask with an aperture between the light source and the exposing optics. The li

Embodiments relate to a method, optical module and auto-focusing system for wafer edge exposure. The optical module comprises a light source emitting light of a wavelength to expose a photoresist, an exposing optics and a mask with an aperture between the light source and the exposing optics. The light emitted from the light source passes through the mask and then reaches the exposing optics to image the aperture on the wafer edge covered with the photoresist to form a focused light spot. The positions of the light source, the mask and the exposing optics, and the size of the aperture are configured such that the optical axis of the incident light is perpendicular to the wafer surface, and the light spot completely covers the wafer edge in the radial direction of the wafer.

대표청구항 ▼

1. An auto-focusing system for wafer edge exposure, comprising: an optical module, comprising: a light source used for emitting light of a wavelength required to expose a photoresist, a first mask with a first aperture;a first optics;a second optics, wherein the light emitted from the light source p

1. An auto-focusing system for wafer edge exposure, comprising: an optical module, comprising: a light source used for emitting light of a wavelength required to expose a photoresist, a first mask with a first aperture;a first optics;a second optics, wherein the light emitted from the light source passing through the first mask, the first optics, and the second optics in sequence and then reaching the wafer edge; the first optics is used for directing the light coming from the first aperture of the first mask to the second optics; and the second optics is used for imaging the first aperture to form a light spot on the wafer edge coated with a photoresist, and wherein the positions of the light source, the first aperture, the first optics, the second optics in the optical module, and a size of the first aperture are configured such that an optical axis of an incident light is perpendicular to the wafer surface and the light spot is characterized by a width that is equal to or greater than a width of the wafer edge region in a radial direction of the wafer;a second mask with a second aperture;a photodetector, wherein the second aperture of the second mask and the first aperture of the first mask are arranged in mirror symmetry with respect to a semi-reflecting surface of the first optics and are of a same size, and wherein the light reflected from the wafer edge passes through the second optics and then is directed to the second mask by the first optics, and the photodetector is arranged on a side of the second mask opposite to the side on which the first optics is arranged, for collecting the light entering the second aperture of the second mask and then outputting a corresponding light intensity signal, wherein a position of the second mask is configured such that a first light intensity signal outputted from the photodetector when the light spot is in focus is larger than a light intensity signal outputted from the photodetector when the light spot is out of focus;a control module for outputting a control signal when the light intensity signal outputted from the photodetector is lower than the first light intensity signal; andan optical path adjusting module, comprising: a first optical path adjusting mechanism attached to the optical module for adjusting the tilt of the optical module with respect to the horizontal plane according to the control signal from the control module, such that the optical axis of the incident light is perpendicular to the wafer surface; anda second optical path adjusting mechanism attached to the optical module for adjusting the position of the optical module in the direction perpendicular to the wafer surface according to the control signal from the control module, such that the light spot is in focus. 2. The auto-focusing system according to claim 1, wherein the second optical path adjusting mechanism comprises: a translation member; a solenoid; anda ferromagnetic shaft;wherein a position of the ferromagnetic shaft is adjusted by adjusting a magnitude of a current flowing through the solenoid, so as to move the optical module along the translation member. 3. The auto-focusing system according to claim 1, wherein the second optical path adjusting mechanism comprises: a translation member; anda stepping motor including a screw rod;wherein the optical module is moved along the translation member by adjusting the screw rod. 4. The auto-focusing system according to claim 1, wherein the first optics comprises a beam splitter. 5. The auto-focusing system according to claim 1, wherein the second optics comprises a lens or a set of lenses. 6. The auto-focusing system according to claim 1, wherein the optical module further comprises a beam homogenizer arranged between the light source and the first mask, wherein the light emitted from the light source is turned into a light beam with uniform intensity distribution by the beam homogenizer. 7. The auto-focusing system according to claim 1, wherein the control module is configured to output a signal for increasing a driving current of the light source, so as to increase the light intensity of the light source. 8. The auto-focusing system according to claim 1, wherein the light source, the photodetector and the second optical path adjusting mechanism are connected to the control module through cables. 9. The auto-focusing system according to claim 1, wherein the photodetector is a two-dimensional array detector. 10. The auto-focusing system according to claim 1, wherein the photodetector is a two-dimensional array of charge coupled device detectors or CMOS detectors. 11. The auto-focusing system according to claim 1, wherein the photodetector is a two-dimensional array detector having at least a 2×2 array. 12. The auto-focusing system according to claim 1, wherein the optical path adjusting module further comprises a support mechanism including a backing plate, a top plate and a spring. 13. A method for wafer edge exposure by means of an auto-focusing system, the auto-focusing system comprising an optical module, a control module, an optical path adjusting module, the optical module comprising a light source, a first mask with a first aperture, a second mask with a second aperture, a first optics, a second optics, and a photodetector; the optical path adjusting module comprising a first optical path adjusting mechanism and a second optical path adjusting mechanism, which are attached to the optical module; the method comprising the following steps: emitting light of a wavelength configured to expose a photoresist from the light source, causing the light emitted from the light source to pass through the first aperture of the first mask and reaching the first optics;directing the light coming from the first aperture of the first mask to the second optics by the first optics;imaging the first aperture on a wafer edge coated with a photoresist by the second optics to form a light spot;configuring positions of the light source, the first aperture of the first mask, the first and second optics in the optical module, and a size of the first aperture, such that an optical axis of an incident light is perpendicular to a wafer surface, and the light spot is characterized by a width that is equal to or greater than a width of the wafer edge region in a radial direction of the wafer, the incident light on the wafer edge being reflected by the wafer edge and the reflected light passing through the second optics and the first optics in sequence;directing the light coming from the second optics to the second mask by the first optics;collecting the light travelling through the second aperture of the second mask and outputting a corresponding light intensity signal by the photodetector;configuring a position and a size of the second aperture of the second mask, such that the second aperture of the second mask and the first aperture of the first mask are arranged in mirror symmetry with respect to a semi-reflecting surface of the first optics and are of a same size, wherein a first light intensity signal outputted from the photodetector when the light spot is in focus is larger than a light intensity signal outputted from the photodetector when the light spot is out of focus;outputting a control signal to a second optical path adjusting mechanism of the optical adjusting module by the control module, when the light intensity signal outputted from the photodetector is lower than the first light intensity signal; andadjusting the position of the optical module in a direction perpendicular to the wafer surface in response to the control signal by the second optical path adjusting mechanism, such that the light spot is in focus. 14. The method according to claim 13, further comprising: rotating the wafer to expose the entire wafer edge with the focused light spot; andremoving the photoresist on the entire wafer edge by a development process. 15. The method according to claim 13, further comprising: turning the light emitted from the light source into a beam of light having uniform intensity distribution by a beam homogenizer; andirradiating the first mask. 16. The method according to claim 13, further comprising outputting a signal for increasing a driving current of the light source by the control module, so as to increase a light intensity of the light source. 17. The method according to claim 13, further comprising adjusting a tilt of the optical module with respect to the horizontal plane by the first optical path adjusting mechanism, such that the optical axis of the incident light is perpendicular to the wafer surface. 18. The method according to claim 17, wherein adjusting the tilt of the optical module comprises: detecting the reflected light with an array detector; anddetermining whether the optical axis of the incident light is perpendicular to the wafer surface based on the distribution symmetry of the reflected light over the array detector.