Inspection device and inspection method
An inspection device according to the present disclosure includes a detector for inspection that includes a plurality of pixels arranged on a light receiving surface and acquires image data by transferring charge produced by light received by the plurality of pixels in a transfer direction at a specified transfer timing, a light source that emits illumination light including pulsed light, a pulse enable circuit that controls emission timing for the light source to emit the illumination light based on the transfer timing, an illumination optical system that illuminates an object to be inspected with the illumination light, a condensing optical system that condenses, on the detector for inspection, light from the object to be inspected illuminated with the illumination light, and a processing unit that inspects the object to be inspected by using the image data of the object to be inspected.
1. An inspection device comprising: a detector for inspection configured to include a plurality of pixels arranged on a light receiving surface including a transfer direction and a direction orthogonal to the transfer direction, and acquire image data by transferring charge produced by light received by the plurality of pixels in the transfer direction at a specified transfer timing; a light source configured to emit illumination light including pulsed light; a pulse enable circuit configured to control an emission timing for the light source to emit the illumination light based on the transfer timing; an illumination optical system configured to illuminate an object to be inspected with the illumination light; a condensing optical system configured to condense, on the detector for inspection, light from the object to be inspected illuminated with the illumination light; and a processing unit configured to inspect the object to be inspected by using the image data of the object to be inspected.
2. The inspection device according to claim 1 , wherein the light source is an LPP light source configured to emit the illumination light by applying laser light to a droplet generated at a generation timing asynchronous to the transfer timing, and the pulse enable circuit controls the emission timing by controlling application of the laser light.
3. The inspection device according to claim 1 , further comprising: a monitor unit configured to acquire luminance of the illumination light detected by illuminating a detector for correction with a part of the illumination light, wherein the processing unit corrects the image data of the object to be inspected by using a previously measured luminance distribution of the illumination light on the light receiving surface and luminance of the illumination light at the emission timing acquired by the detector for correction, and the processing unit inspects the object to be inspected by using the corrected image data of the object to be inspected.
4. The inspection device according to claim 3 , wherein the processing unit comprises: a position recording shift register configured to record positions of the plurality of pixels arranged in the transfer direction at the emission timing; and a luminance register configured to record luminance of the illumination light at the emission timing, wherein the processing unit corrects the image data of the object to be inspected by using the previously measured luminance distribution of the illumination light on the light receiving surface, positions of pixels recorded in the position recording shift register, and luminance of the illumination light recorded in the luminance register.
5. The inspection device according to claim 4 , wherein the processing unit includes a plurality of the position recording shift registers and a plurality of the luminance registers corresponding to a plurality of pulsed light emitted from the light source during a time of integration of charge of the plurality of pixels, the processing unit shifts positions of the respective pixels recorded in each of the position recording shift registers in the transfer direction in synchronization with the transfer timing, and the processing unit corrects image data of the object to be inspected by using the positions shifted and output in each of the position recording shift registers, luminance of the illumination light recorded in each of the luminance registers, and the previously measured luminance distribution of the illumination light on the light receiving surface.
6. The inspection device according to claim 3 , wherein the detector for inspection is a detector including a TDI sensor, and the detector for correction is a detector including a photodiode.
7. An inspection method comprising: a step of preparing a detector for inspection configured to include a plurality of pixels arranged on a light receiving surface including a transfer direction and a direction orthogonal to the transfer direction, and acquire image data by transferring charge produced by light received by the plurality of pixels in the transfer direction at a specified transfer timing; a step of preparing a light source configured to emit illumination light including pulsed light; a step of emitting the illumination light from the light source while controlling emission timing for the light source to emit the illumination light based on the transfer timing; a step of illuminating an object to be inspected with the illumination light; a step of condensing, on the detector for inspection, light from the object to be inspected illuminated with the illumination light; and a step of inspecting the object to be inspected by using the image data of the object to be inspected.
8. The inspection method according to claim 7 , wherein the step of preparing a light source configured to emit illumination light including pulsed light prepares an LPP light source configured to emit the illumination light by applying laser light to a droplet generated at a generation timing asynchronous to the transfer timing, and the step of emitting the illumination light controls the emission timing by controlling application of the laser light.
9. The inspection method according to claim 7 , further comprising a step of preparing a detector for correction configured to acquire luminance of the illumination light; a step of acquiring luminance of the illumination light by illuminating the detector for correction with a part of the illumination light; and a step of correcting the image data of the object to be inspected by using a previously measured luminance distribution of the illumination light on the light receiving surface and luminance of the illumination light at the emission timing acquired by the detector for correction, wherein the step of inspecting the object to be inspected inspects the object to be inspected by using the corrected image data of the object to be inspected.
10. The inspection method according to claim 9 , wherein the step of correcting the image data of the object to be inspected prepares a position recording shift register configured to record positions of the plurality of pixels arranged in the transfer direction at the emission timing, and a luminance register configured to record luminance of the illumination light at the emission timing, and corrects the image data of the object to be inspected by using a previously measured luminance distribution of the illumination light on the light receiving surface, positions of pixels recorded in the position recording shift register, and luminance of the illumination light recorded in the luminance register.
11. The inspection method according to claim 10 , wherein the step of correcting the image data of the object to be inspected prepares a plurality of the position recording shift registers and a plurality of the luminance registers corresponding to a plurality of pulsed light emitted from the light source during a time of integration of charge of the plurality of pixels, shifts positions of the respective pixels recorded in each of the position recording shift registers in the transfer direction in synchronization with the transfer timing, and corrects image data of the object to be inspected by using the positions shifted and output in each of the position recording shift registers, luminance of the illumination light recorded in each of the luminance registers, and the previously measured luminance distribution of the illumination light on the light receiving surface.
12. The inspection method according to claim 9 , wherein the detector for inspection is a detector including a TDI sensor, and the detector for correction is a detector including a photodiode.