JP2009265384A - Optical member, light source device and inspecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical member, preventing a reflecting mirror of a light source device from being tarnished without requiring specific facility. <P>SOLUTION: The optical member includes: a support part (a transparent glass 16a); a reflecting part 16b supported by the support part and reflecting light 14b having a desired wavelength (e.g. ultraviolet ray light to visible light ray); and a heat ray absorbing part 16c, supported by the support part, absorbing at least light (e.g. infrared ray light) having a wavelength other than the desired wavelength to generate heat, and heating the reflecting part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical member, a light source device having the optical member, and an inspection device having the optical member or the light source device, which are used in an illumination light source such as a semiconductor wafer, a liquid crystal display substrate inspection device, and an exposure device.

  As an illumination light source, a light source device equipped with a Deep UV lamp or a mercury lamp that emits short-wavelength illumination light is known. In these illumination light sources that emit light of short wavelengths, various pollutants suspended in the vicinity of the light source are activated by ultraviolet rays contained in the light emitted from the light source, and substances generated by chemical reactions between the pollutants are the light source. There is a problem of reducing the reflection intensity by attaching to the reflection mirror of the apparatus (fogging the surface of the reflection mirror and consequently reducing the reflection intensity).

As a substance that cloudes the surface of such a reflector, for example, ammonium sulfate (NH ₄ ) ₂ SO ₄ is available. This ammonium sulfate (NH ₄ ) ₂ SO ₄ is known to sublime at a temperature of 120 ° C. or higher.

Therefore, a light source device equipped with a heater for heating the reflecting mirror as a fogging preventing means has been proposed (see Patent Document 1).
Japanese Patent No. 3266156

  The above-described anti-fogging means requires a heater provided in the reflecting mirror and a controller that controls the amount of electricity supplied to the heater so as not to overheat.

  The present invention provides an optical member, a light source device, and an inspection device having the optical member or the light source device capable of preventing the reflection mirror of the light source device from being fogged without requiring special equipment. Objective.

  The optical member according to claim 1 of the present invention that achieves the above object includes a support portion, a reflection portion that is supported by the support portion and reflects light having a desired wavelength, and the support portion and the reflection portion. And a heat ray absorbing part that absorbs heat rays transmitted through the reflection part and heats the reflection part.

  The optical member according to claim 2 of the present invention is characterized in that the reflecting portion transmits light having a wavelength other than the desired wavelength.

  The optical member according to claim 3 of the present invention is characterized in that the heat ray absorbing portion is a heat ray absorbing film provided on the surface of the support portion, and the reflecting portion is provided on the heat ray absorbing film. And

  A light source device according to a fourth aspect of the present invention includes a light source and an elliptical mirror that includes the optical member according to any one of the first to third aspects and reflects light from the light source. It is characterized by that.

  An inspection apparatus according to claim 5 of the present invention is an inspection apparatus for inspecting the surface of an object to be inspected, and is an optical member according to any one of claims 1 to 3 or a light source according to claim 4. It is equipped with a device.

  According to the present invention, it is possible to prevent the reflection mirror of the light source device from being fogged without requiring special equipment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS An embodiment of an optical member, a light source device equipped with the optical member, and an inspection device equipped with the optical member or the light source device will be described below with reference to FIGS.

  FIG. 1 is a schematic view of a light source device equipped with the optical member of the present invention.

  As shown in FIG. 1, a light source device 10 includes, in a lamp house 12, for example, a deep UV (deep ultraviolet lamp) lamp 14 as a light source and an elliptical mirror as an optical member that reflects light emitted from the deep UV lamp 14. 16 and a mirror 18 that reflects the light from the elliptical mirror 16 and guides it out of the lamp house 12.

  The Deep UV lamp (deep ultraviolet lamp) 14 is a xenon lamp based on a metal vapor such as mercury. As a light source, a mercury lamp or the like can be used in addition to the Deep UV lamp 14.

  As shown in detail in FIG. 2, the elliptical mirror 16 includes a transparent glass 16a as a support portion, a reflecting portion 16b disposed on the inner surface of the transparent glass 16a, and an inner surface (the transparent glass 16a provided with the reflecting portion 16b). A heat ray absorbing portion (heat ray absorbing film) 16c disposed between the surface and the reflecting portion 16b).

  The transparent glass 16a has a function of supporting the reflecting portion 16b and the heat ray absorbing portion (heat ray absorbing film) 16c, and light reflected by the reflecting portion 16b formed along the inner surface of the transparent glass 16a is reflected on the mirror 18. It has a light collecting function for focusing, and is formed in a substantially bell shape (see FIG. 1) as a whole.

  The reflection unit 16b reflects light 14b having a desired wavelength out of the light 14a emitted from the Deep UV lamp 14, for example, light having a wavelength in the range of 248 nm to 546 nm with high efficiency, and light 14c having other wavelengths, for example, wavelength Dielectric multilayer film in which light having a wavelength shorter than 248 nm, light having a wavelength longer than 546 nm, or non-reflecting light having a wavelength in the range of 248 nm to 546 nm is transmitted, and a plurality of dielectrics having different refractive indexes are laminated. Is a kind of dichroic mirror formed from

The heat ray absorbing portion (heat ray absorbing film) 16c is formed along the inner surface of the transparent glass 16a (between the surface of the transparent glass 16a on which the reflecting portion 16b is provided and the reflecting portion 16b), and is transmitted through the reflecting portion 16b. It absorbs the generated heat rays (infrared rays) and generates heat, and the sublimation temperature of ammonium sulfate (NH ₄ ) ₂ SO ₄ together with the heat from the deep UV lamp 16a (heat that heats the inner surface of the transparent glass 16a to near 120 ° C.) To 120 ° C. or higher.

  The material constituting the heat ray absorbing portion (heat ray absorbing film) 16c may be any material as long as it absorbs heat rays (infrared rays) and generates heat. For example, a laminated film composed of MgF2, ITO and ZrO2 Or a laminated film composed of ZnO and Ag can be used.

  The heat ray absorbing portion (heat ray absorbing film) 16c has a thickness of several tens to several hundreds of nm by, for example, chemical vapor deposition (plasma CVD, thermal CVD, laser CVD, etc.) or physical vapor deposition (vacuum vapor deposition, sputtering, etc.). It is formed.

  According to the optical device 10 described above, light from the ultraviolet region to the visible region (for example, a wavelength of 248 nm to 546 nm), which is the light 14b having a desired wavelength, out of the light from the Deep UV lamp 14, is reflected by the reflecting portion 16b. The light is condensed on the mirror 18, reflected from the mirror 18, and emitted from the lamp house 12 to the outside.

  Further, for example, light in the infrared region, which is light 14c in the other wavelength region, passes through the reflecting portion 16b and is irradiated to the heat ray absorbing portion (heat ray absorbing film) 16c. The heat ray absorbing portion (heat ray absorbing film) 16c absorbs this light to cause an exothermic reaction, and heats the adjacent reflecting portion 16b.

The reflecting portion 16b is made of ammonium sulfate (NH ₄ ) ₂ SO by heat from the Deep UV lamp 16a (heat that heats the inner surface of the transparent glass 16a to near 120 ° C.) and heat from the heat ray absorbing portion (heat ray absorbing film) 16c. It is heated to a temperature of 120 ° C. or higher, which is the sublimation temperature of ₄ . While the Deep UV lamp 16a is lit, the reflecting portion 16b is maintained at a temperature of 120 ° C. or higher. As a result, various pollutants floating in the vicinity of the Deep UV lamp 16a are activated and the pollutants are chemically separated. Even if the substance generated by the reaction adheres, it is sublimated immediately and there is no possibility that the surface (reflecting surface) of the reflecting portion 16b becomes cloudy.

  In addition, since the heating means such as a heater and a controller for controlling the amount of power to the heater are not equipped to heat the reflecting portion 16b, the apparatus does not become large and the equipment is not costly. There is no need to use special energy such as electrical energy.

  Moreover, since the light 14c which permeate | transmits the reflection part 16b which was not used until now among the light 14a from the DeepUV lamp | ramp 14 is utilized, the effective utilization of light energy can be aimed at.

  FIG. 3 shows an embodiment of the inspection apparatus 20 having the light source device 10 described above.

  For example, the inspection apparatus 20 inspects the surface properties of the semiconductor wafer 21 (the presence or absence of chips, the presence or absence of particles, the presence or absence of substances (such as photoresist residues) that interfere with processing of the semiconductor wafer). An inspection table 22 on which the semiconductor wafer 21 is placed, a light source device 10 that illuminates the surface of the semiconductor wafer 21 on the inspection table 22, a CCD sensor that receives light reflected from the surface of the semiconductor wafer 21, and the like. The light receiving device 23 is provided.

The light source device 10 is driven to illuminate the surface of the semiconductor wafer 21 on the inspection table 22, while the light receiving device 23 receives reflected light from the semiconductor wafer 21, and photoelectrically converts the received reflected light into an electrical signal. The image is sent from the light receiving device 23 to an image processing device (not shown), subjected to image processing, and the surface of the semiconductor wafer 21 is inspected. At the time of this inspection, the pollutant near the light source device 10 causes a chemical reaction due to the light from the Deep UV lamp 14, and the pollutant adheres to the reflecting portion 16b of the elliptical mirror 16 to fog the reflecting portion 16b and lower the reflection efficiency. Although there is a possibility, since the reflecting portion 16b is maintained at a temperature of 120 ° C. or higher as described above, even if ammonium sulfate (NH ₄ ) ₂ SO _{4 that} makes the surface (reflecting surface) of the reflecting portion 16b cloudy is attached. There is no risk that the sublimation rate is immediately sublimated and the reflectance is lowered, and the surface of the semiconductor wafer 21 can be continuously illuminated with a predetermined illuminance.

  The present invention is not limited to the above embodiment.

  Although the case where the optical member of the present invention is applied to the elliptical mirror 16 of the light source device 10 is shown, it can be applied to a dichroic mirror arranged in an optical path other than the light source device 10.

  Moreover, although the case where the transparent glass 16a was used as a support part was shown, it is not necessary to be transparent glass, and it is possible to use metal support parts, such as an aluminum alloy.

It is the schematic of the light source device equipped with the optical member of this invention. It is the elements on larger scale of the elliptical mirror as an optical member in FIG. It is the schematic of the inspection apparatus equipped with the optical apparatus 10 of FIG.

Explanation of symbols

10 Light source device 12 Lamp house 14 Deep UV lamp (light source)
14a, b Light 16 Elliptical mirror 16a Transparent glass (supporting part)
16b Reflector 16c Heat ray absorber

Claims (5)

A support part;
A reflective part that is supported by the support part and reflects light of a desired wavelength;
A heat ray absorbing part that is supported between the support part and the reflecting part, absorbs heat rays transmitted through the reflecting part, and heats the reflecting part;
An optical member comprising: The optical member according to claim 1,
The optical member, wherein the reflection part transmits light having a wavelength other than the desired wavelength. The optical member according to claim 1 or 2,
The said heat ray absorption part is a heat ray absorption film provided in the said support part surface, The said reflection part is provided on the said heat ray absorption film, The optical member characterized by the above-mentioned. A light source;
An elliptical mirror comprising the optical member according to any one of claims 1 to 3, and reflecting light from the light source;
A light source device comprising: An inspection device for inspecting the surface of an inspection object,
An inspection device comprising the optical member according to any one of claims 1 to 3 or the light source device according to claim 4.