JP6245533B2 - Inspection apparatus and imaging device manufacturing method - Google Patents

Description

  The present invention relates to an illumination device that illuminates an object to be irradiated, an inspection device including the illumination device, and a method for manufacturing an image sensor using the inspection device.

  Solid-state image sensors used in digital cameras and the like, for example, CCD-type or CMOS-type image sensors, are integrated on the surface of a semiconductor wafer (hereinafter simply referred to as a wafer) by a CVD (chemical vapor deposition) process, a photolithography process, or the like. It is formed by stacking circuits. At this time, in general, a large number of solid-state image sensors are formed in a matrix on the surface of one wafer, and performance inspection is performed with each solid-state image sensor aligned on the wafer. Elements that pass this inspection are separated from the wafer and used in a digital camera or the like.

  Conventionally, in order to inspect a plurality of solid-state image sensors arranged in alignment on a wafer, an illumination device that illuminates an inspection target element on the wafer surface with illumination light with high illuminance uniformity, and a prober that moves the wafer An inspection apparatus having a tester that takes in an electrical output of an element to be inspected and inspects performance is used. A conventional lighting device uses non-polarized broadband light (white light) generated from a light source made of a lamp having a filament as illumination light (see, for example, Patent Document 1).

  In addition, there is used an apparatus for inspecting a pattern defect by making linearly polarized parallel light (illumination light) incident on the surface of a wafer on which a repeated pattern is formed and detecting light reflected from the pattern. In this inspection apparatus, for example, a concave reflecting mirror is used to convert a linearly polarized divergent light beam from a light source into parallel light and guide it to the wafer surface. At this time, rotation of the polarization plane of illumination light (polarization azimuth angle of linearly polarized light) occurs due to reflection by the concave reflecting mirror. Therefore, in order to suppress this rotation, for example, in a divergent light beam from a light source (in a non-parallel light beam) A plane parallel plate is disposed (see, for example, Patent Document 2).

JP 2006-222325 A US Pat. No. 7,307,725

  As a condition of illumination light emitted from the illumination device in order to inspect the solid-state imaging device, it is preferable that the light is first non-polarized light (light having a polarization degree of approximately 0%) just after being emitted from the lamp. However, even when non-polarized light is emitted from the light source, the degree of polarization is changed by an optical member such as a mirror for bending the optical path in the optical path in the middle of the illuminating device, and illumination is applied to the inspection target element When the degree of polarization of light becomes large (the degree of polarization exceeds an allowable range), the inspection accuracy may decrease due to polarization dependency of a detector or the like.

  For example, when inspecting the polarization characteristics of a solid-state imaging device, the illumination light can be set to linearly polarized light in an arbitrary direction by passing the illumination light through a linear polarizing plate whose rotation angle can be adjusted, for example. Is preferred. However, if the illumination light before passing through the linear polarizing plate is not non-polarized light, the amount of light varies depending on the polarization direction (polarization azimuth angle) of the illumination light after passing through the linear polarizing plate, resulting in a decrease in inspection accuracy. There is a risk.

  In view of such circumstances, an aspect of the present invention aims to illuminate an inspection target element with non-polarized light (light having a polarization degree of approximately 0%).

According to the present invention, in an inspection apparatus for inspecting an object to be inspected, a first optical member on which light generated from a light source is incident, and light having transparency to the light, and non-polarized light is incident on the object to be inspected. A second optical member that changes the degree of polarization of the light so as to detect the output from the object illuminated by the light from the illumination device, and based on the detection result And the second optical member is arranged at a position where the light emitted from the center of the light source is substantially parallel to the optical axis of the illuminating device. An inspection device is provided.
Moreover, in the inspection apparatus, as an example, the second optical member includes a plate-like optical member, and is disposed to be inclined with respect to a plane perpendicular to the optical axis of the illumination apparatus. The apparatus further includes an optical integrator on which light from the light source is incident, and a condenser lens that performs Koeler illumination of light from the light exit surface of the optical integrator to the inspection object in a substantially telecentric manner .

The present invention also describes the following invention.
According to the first aspect of the present invention, in the illumination device that illuminates the irradiated object, the light source unit that generates non-polarized light and the first light path that bends at least a part of the light path generated from the light source unit. An optical member, and a second optical member that is transparent to the light and reduces the degree of polarization of the light that is increased by the first optical member, the second optical member being the center of the light source unit There is provided an illuminating device in which light emitted from the illuminating device is disposed at a position substantially parallel to the optical axis of the illuminating device.
According to the second aspect, in the illumination device that illuminates the irradiated object, the light source unit that generates non-polarized light, the first optical member that bends the optical path of at least part of the light from the light source unit, and the An optical integrator that receives light from the light source unit, and a second optical member that has transparency to the light and that reduces the degree of polarization of the light that is increased by the first optical member. The member is provided with an illuminating device in which light emitted from the center of the light emitting surface of the optical integrator is arranged at a position substantially parallel to the optical axis of the illuminating device.

  According to the third aspect, in the illumination device that illuminates the irradiated object, the light source unit that generates light, the first optical member that bends at least a part of the optical path of the light generated from the light source unit, and the A second optical member having transparency to light and changing a degree of polarization of the light so that non-polarized light is incident on the irradiated object, the second optical member of the light source unit A lighting device is provided in which light emitted from the center is arranged at a position substantially parallel to the optical axis of the lighting device.

  According to the fourth aspect, in the illumination device that illuminates the irradiated object, the light source unit that generates light, the first optical member that bends at least a part of the optical path of the light generated from the light source unit, and the light source An optical integrator on which light from the unit is incident, and a second optical member that has transparency to the light and changes the degree of polarization of the light so that non-polarized light is incident on the irradiated object, The second optical member is provided with an illuminating device in which light emitted from the center of the light exit surface of the optical integrator is disposed at a position substantially parallel to the optical axis of the illuminating device.

  According to the fifth aspect, in the illumination device that illuminates the irradiated object, the light source unit that generates non-polarized light, the optical integrator on which the light from the light source unit is incident, and the light from the light source unit A first optical member that bends the light source, a condenser lens that provides Koeler illumination of light from the light exit surface of the optical integrator to the irradiated object in a substantially telecentric manner, and the condenser lens and the irradiated object. There is provided an illuminating device including a plane-parallel plate that has transparency to the light and reduces the degree of polarization of light that is increased by the first optical member.

Moreover, according to the 6th aspect, with the illumination apparatus of the 1st-5th aspect, the stage by which the to-be-inspected object illuminated with the light from the illumination apparatus is mounted, and the light from the illumination apparatus An inspection apparatus is provided that includes an inspection unit that detects an output from the illuminated inspection object and inspects the inspection object based on a result of the detection.
Moreover, according to the 7th aspect, the manufacturing method of an image pick-up element including the process of test | inspecting an image pick-up element with the test | inspection apparatus of the aspect of this invention is provided.

  According to the aspect of the present invention, the object to be inspected can be illuminated with non-polarized light (light having a polarization degree of approximately 0%).

It is a figure showing the inspection device concerning a 1st embodiment. (A) is a diagram showing the wavelength dependence (incident angle 45 °) of the reflectance of the aluminum-coated mirror, (b) is a diagram showing the incident angle dependence (wavelength 550 nm) of the reflectance, and (c) is the diagram The figure which shows the wavelength dependence (incident angle 45 degrees) of the polarization degree of a mirror, (d) is a figure which shows the incident angle dependence (wavelength 550nm) of the polarization degree. (A) is a graph showing the incident angle dependency of the energy reflectance per one reflecting surface (substrate material is BK7), and (b) is the incident angle dependency of the energy transmittance per one substrate (two surfaces). (C) is a diagram showing the incident angle dependence of the degree of polarization of transmission of a plane parallel plate (substrate material is BK7), (d) is a plane parallel plate (substrate material is BK7). It is a figure which shows the wavelength dependence (incidence angle of 28 degrees) of the degree of polarization by. It is a figure which shows the inspection apparatus of the state which has arrange | positioned the linear polarizing plate above a wafer. It is a figure which shows the incident angle dependence (substrate material is SF6) of the polarization degree of the transmission of a parallel plane plate. It is a figure which shows the inspection apparatus which concerns on 2nd Embodiment. (A) is a top view which shows the illumination area of the inspection apparatus of FIG. 6, (b) is a top view which shows another illumination area. It is a perspective view which shows the illuminating device which concerns on 3rd Embodiment. It is a flowchart which shows an example of the manufacturing process of an image pick-up element.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an inspection apparatus 100 according to the present embodiment. As an example, the inspection apparatus 100 has the performance of a plurality of CCD-type or CMOS-type solid-state imaging elements 58 (see FIG. 7A) in a state of being aligned on the surface of a wafer (semiconductor wafer) 50 made of silicon or the like. It is to be inspected. The inspection apparatus 100 includes an illumination device 80 that illuminates the irradiated surface 16 of the surface of the wafer 50, which is an object to be inspected, with illumination light IL having a uniform illuminance distribution, a prober 90 that moves the wafer 50, and an inspection target on the surface of the wafer 50. The tester 56 that takes in the electrical output of the solid-state image pickup device (device to be inspected) and inspects its performance, the main controller 53 comprising a computer that controls the overall operation of the entire device, and the optics that constitutes the illumination device 80 A frame mechanism (not shown) for supporting members and the like. Hereinafter, in the plane in which the wafer 50 moves, the X axis is taken in the direction parallel to the paper surface of FIG. 1, the Y axis is taken in the direction perpendicular to the paper surface in FIG. 1, and the Z axis is taken in the direction perpendicular to the plane. The rotation direction around an axis parallel to the axis will be described as the θz direction.

  First, the prober 90 can contact the stage 51 on which the wafer 50 is placed, the stage driving device 52 that drives the stage 51 in the X direction, the Y direction, and the θz direction, and the output terminal of the inspection target element on the surface of the wafer 50. A plurality of probe pins 55. The tester 56 inspects the performance of the inspection target element from the electrical signal (output) of the inspection target element (illuminated by the illumination device 80) obtained through the probe pin 55. The main control device 53 moves the stage 51 (wafer 50) via the stage driving device 52 based on the detection result of the alignment system (not shown), and the inspection target element is illuminated on the illuminated surface 16 of the illumination device 80. Move in.

Moreover, the illuminating device 80 includes the light source 1 that emits non-polarized illumination light IL that includes a wide wavelength range of approximately 400 to 700 nm. The illumination light IL emitted from the light source 1 is white light including red light (center wavelength: 600 nm), green light (center wavelength: 555 nm), and blue light (center wavelength: 450 nm), which are the three primary colors received by the image sensor. It is. For example, a halogen lamp having a filament is used as the light source 1. As the light source 1, a general incandescent lamp or a xenon lamp can be used.

  Further, the illumination device 80 is substantially in the + X direction from a plurality of optical members arranged in order from the light source 1 toward the irradiated surface 16, that is, the collector lens 2, the filter group 3, the relay optical system 4, and the relay optical system 4. It has a folding mirror 5 made of a plane mirror that bends the emitted light beam approximately 90 ° in the −Z direction, and a fly-eye lens 6 (optical integrator) for reducing illumination unevenness. Further, the illumination device 80 condenses the light flux from the fly-eye lens 6 and telecentricly illuminates the irradiated surface 16, and is inclined with respect to the plane 15 perpendicular to the optical axis AX of the optical system of the illumination device 80. And a linearly polarizing plate (polarizer) 9 supported so as to be able to be inserted into and removed from the illumination light path and to be rotatable in the θz direction. The filter group 3 includes a heat ray absorption filter 3A, a replaceable color filter 3B, a replaceable ND filter 3C for controlling the amount of light, a band pass filter (not shown), and the like.

  As an example, the folding mirror 5 is formed by forming a metal film such as aluminum on the reflecting surface of a glass plate. The reflecting surface 5a of the folding mirror 5 is inclined by 45 ° around an axis parallel to the Y axis with respect to the optical axis AX of the illumination device 80. As an example, the fly-eye lens 6 is formed by closely bonding a plurality of lens elements having a square cross-sectional shape. At this time, since the entrance surface of the fly-eye lens 6 and the irradiated surface 16 are conjugated by the condenser lens 7, the shape of the illumination area of the irradiated surface 16 is also square. The material (glass material) of the polarization correction plate 8 is desirably a material having a refractive index as high as 1.5 or more.

  In addition, the illumination device 80 is provided with an angle adjustment mechanism 10 that adjusts an inclination angle α of the polarization correction plate 8 with respect to the plane 15 and a linear polarization plate 9 in the illumination optical path as necessary, and the linear polarization plate in the illumination optical path. It has an insertion / removal rotation mechanism 20 that rotates 9 in the θz direction. The angle adjustment mechanism 10 includes a support portion 11 that rotatably supports an end portion of the polarization correction plate 8 in the −X direction, a support portion 12 that supports an end portion of the polarization correction plate 8 in the + X direction, and an arcuate guide portion 14. And the drive part 13 which moves the support part 12 via a gear mechanism along the guide part 14 is provided. The drive unit 13 may be a manual, but may be driven by a drive motor. Further, it is desirable to provide a rotation mechanism (not shown) that integrally rotates the polarization correction plate 8 and the angle adjustment mechanism 10 in the θz direction. In this case, the tilt angle α of the polarization correction plate 8 can be varied in an arbitrary direction with respect to the optical axis Ax of the illumination device 80 by the angle adjustment mechanism 10 and a rotation mechanism (not shown). The tilt angle α of the polarization correction plate 8 of the polarization correction plate 8 can be arbitrarily set in an arbitrary direction with respect to the optical axis Ax of the illumination device 80 without being limited to the angle adjustment mechanism 10 and the rotation mechanism (not shown). If it is a mechanism, for example, an existing mechanism such as kinematic support of the polarization correction plate 8 at three points can be applied. The insertion / removal rotation mechanism 20 rotates the support frame 21 that supports the linear polarizing plate 9, the bearing 22 that rotatably supports the support frame 21 on the inside, and the outer frame of the bearing 22 to rotate the linear polarizing plate 9 in the bearing 22. A first drive motor 23 installed in the illumination optical path and retracted from the illumination optical path, and a second drive motor 24 that rotates the support frame 21 (linearly polarizing plate 9) in the bearing 22 in the θz direction. Note that the configurations of the angle adjustment mechanism 10 and the insertion / removal rotation mechanism 20 are not limited to the above-described configurations, and a known technique may be applied.

  In the illuminating device 80, the light beam (illumination light IL) emitted from the light source 1 is converted (collimated) into a substantially parallel light beam substantially in the + X direction by the collector lens 2 and enters the filter group 3. The position where the filter group 3 is disposed is preferably near the back focal point of the collector lens 2 where the beam diameter is small or near the intermediate position (position where a light source image can be generated) of the relay optical system 4. Further, the filters 3A to 3C of the filter group 3 may be arranged at different positions. The filters 3A to 3C and the like may be arranged at an angle in order to reduce the influence of multiple reflection. The light beam that has passed through the filter group 3 is converted by the relay optical system 4 into a light beam having a size and a numerical aperture (NA) appropriate for entering the fly-eye lens 6, and the fly-eye lens 6 is passed through the folding mirror 5. Is incident on.

  In the present embodiment, the folding mirror 5 is disposed between the relay optical system 4 and the fly-eye lens 6 in order to reduce the size of the illumination device 80 and thus the inspection device 100. The folding mirror 5 is desirably installed at a position where light from the center of the light source 1 or the center of the exit surface of the fly-eye lens 6 is substantially parallel to the optical axis AX. If it is this position, since the light flux condensed on each position of the irradiated surface 16 is a light flux whose incident angle distribution to the folding mirror 5 is substantially equal to each other, the folding mirror 5 is inclined. Unevenness of light intensity (inclination unevenness) is unlikely to occur. If the folding mirror 5 is arranged at an intermediate position of the relay optical system 4, the incident angle distribution of the light to the folding mirror 5 differs depending on the condensing position of the irradiated surface 16. In this case, since the reflectance of the mirror generally depends on the incident angle, unevenness in the amount of illumination light (inclination unevenness) occurs.

  Then, the irradiated surface 16 is illuminated by the condenser lens 7 with a light beam emitted from the fly-eye lens 6 so as to be Koehler illumination using the exit surface of the fly-eye lens 6 as a secondary light source. At this time, the front focal position of the condenser lens 7 is generally set to the exit surface of the fly-eye lens 6 (the surface on which the pupil surface or the secondary light source is formed) so as to achieve telecentric illumination.

  Next, the operation of the polarization correction plate 8 in this embodiment will be described. When inspecting the inspection target element on the surface of the wafer 50 by the inspection apparatus 100 according to the present embodiment, as a first inspection method, for example, in order to eliminate the influence of the polarization dependence of the inspection target element, the non-polarized light is applied to the inspection target element. Irradiate a light flux. In this first inspection method, the linearly polarizing plate 9 is retracted outside the illumination optical path. As the light source 1, a light source that emits non-polarized illumination light IL is used. However, since the reflection mirror 5 used to reduce the size of the illumination device 80 has different reflectances for s-polarized light and p-polarized light, the degree of polarization of the light beam reflected by the folding mirror 5 changes (polarized light). For example, the degree of polarization may be about several percent. More specifically, since a linearly polarized light component is generated in the light beam reflected by the folding mirror 5, the degree of polarization may increase.

  It should be noted that the intensity difference between the polarized light component in the X direction (p-polarized light with respect to the folding mirror 5) and the polarized light component in the Y direction (s-polarized light with respect to the folded mirror 5) with respect to S1 and the X direction. S2 is the intensity difference between the polarization component tilted by 45 ° and the polarization component tilted by 135 °, S3 is the difference in intensity between right circular polarization and left circular polarization, and ST is the intensity of the total luminous flux. Defined in

Polarization degree = {(S1 ² + S2 ² + S3 ² ) ^1/2 / ST} × 100 (%) (1)
Hereinafter, light that can be regarded as having a degree of polarization of approximately 0% (light having a degree of polarization of about 1% or less) is referred to as non-polarized light.
The mirror coating used for white light is generally an aluminum coat. Therefore, as an example, if the folding mirror 5 is also a mirror (aluminum mirror) having an aluminum coating on the reflecting surface, the aluminum mirror has a reflectivity of approximately 90% at 45 ° incidence. Further, in the aluminum mirror, the reflectance characteristics for s-polarized light and p-polarized light are about 5% as shown in FIG. 2A (when the incident angle is 45 °) and FIG. 2B (when the wavelength is 550 nm). There is a difference.

  In the inspection apparatus 100 for inspecting a solid-state image sensor as in the present embodiment, it is desirable to support a wide wavelength range. However, if the mirror is compatible with a wide wavelength range, polarized light tends to be generated. When the inspection light may be a single-wavelength light such as a laser beam, the single-wavelength mirror coating can obtain a very high reflectance of almost 100% for both s-polarized light and p-polarized light. Therefore, almost no polarization occurs.

  The wavelength dependence and incidence angle dependence of the degree of polarization of reflected light when a non-polarized light beam enters the folding mirror 5 (here, an aluminum mirror) are shown in FIG. 2 (d) (when wavelength is 550 nm). The degree of polarization of the reflected light from the aluminum mirror has a small wavelength dependency (see FIG. 2C), but has a large incident angle dependency (see FIG. 2D). Since the incident angle of the light beam with respect to the folding mirror 5 is in the vicinity of 45 °, the degree of polarization of the reflected light from the folding mirror 5 is approximately 3%. In addition, when there is an optical member such as a beam splitter disposed obliquely with respect to a plane perpendicular to the optical axis in the illumination optical path, the degree of polarization of the light beam after passing through the optical member changes. .

  In the present embodiment, a change in the degree of polarization (an increase in the degree of polarization) generated in the light beam reflected by the folding mirror 5 is reduced (more specifically, linearly polarized light generated in the light beam reflected by the folding mirror 5). In order to reduce the component, a polarization correction plate 8 made of a parallel plane plate inclined is disposed between the condenser lens 7 and the irradiated surface 16. When the plane-parallel plate is disposed obliquely, the transmittance differs between the s-polarized light and the p-polarized light. Therefore, the intensity difference between the s-polarized light and the p-polarized light generated by the folding mirror 5 can be reduced, and the degree of polarization can be lowered. As an example, BK7 (d-line refractive index = 1.5168) is used as the material of the polarization correction plate 8. Although the refractive index of BK7 is not so high with respect to 1.5, the availability of a large plane-parallel plate is good.

Here, the relationship between the incident angles of the p-polarized light and the s-polarized light flux by the plane-parallel plate and the Fresnel reflectivity (energy reflectivity) Rp, Rs is as follows.
Rp = tan ² (θ ₁ −θ ₂ ) / tan ² (θ ₁ + θ ₂ ) (2)
Rs = sin ² (θ ₁ −θ ₂ ) / sin ² (θ ₁ + θ ₂ ) (3)
sinθ ₁ = nsinθ ₂ (4)
Here, θ ₁ is an incident angle in air, θ ₂ is a refraction angle in a plane parallel plate, and n is a refractive index of the plane parallel plate. When the material of the plane-parallel plate (polarization correction plate 8) is BK7, the relationship between the incident angle and the energy reflectance of p-polarized light and s-polarized light (per reflecting surface) is shown in FIG. FIG. 3B shows the relationship between the polarized light and s-polarized energy transmittance (per parallel plane plate), and FIG. 3B shows the relationship between the incident angle when non-polarized light is incident and the degree of polarization of the transmitted light. FIG. 3D shows the relationship between the wavelength when non-polarized light is incident and the degree of polarization of the transmitted light (when the incident angle is 28 °). Since the wavelength dependence of the refractive index of the optical glass is small, as shown in FIG. 3D, the wavelength dependence of the degree of polarization of transmitted light is also small. The incident angle of the light beam parallel to the optical axis with respect to the surface 8a (the surface on which light is incident) of the polarization correction plate 8 of FIG. 1 is the same as the inclination angle α with respect to the plane 15 adjusted by the angle adjusting mechanism 10.

  In the present embodiment, since the s-polarized light in the folding mirror 5 has a higher reflectance than the p-polarized light, if the plane parallel to the paper surface (XZ plane) in FIG. A linearly polarized light component in a direction perpendicular to the paper surface of FIG. 1 (Y-axis direction) is generated (that is, the degree of polarization of the reflected light of the folding mirror 5 is increased). In the folding mirror 5, a polarization component is generated due to the difference between the phase difference and the reflectance, but the phase of the light emitted from the non-polarized light source 1 is random, and the influence of the phase difference is small.

On the other hand, in the polarization correction plate 8 (parallel plane plate), the p-polarized light has higher transmittance than the s-polarized light. Therefore, the arrangement of FIG. 1 (the polarization correction plate 8 is parallel to the Y axis with respect to the plane 15). 1), when a non-polarized light beam enters the polarization correction plate 8, a linearly polarized light component in a direction parallel to the paper surface of FIG. 1 (X-axis direction) is generated.
Therefore, in the combination of the folding mirror 5 and the polarization correction plate 8, their linear polarization components (linear polarization component in the Y-axis direction and linear polarization component in the X-axis direction) cancel each other. By adjusting the (incident angle), the degree of polarization of the light beam that passes through the polarization correction plate 8 and travels toward the irradiated surface 16 can be reduced. When the glass material of the polarization correction plate 8 is BK7, the polarization angle of the transmitted light is about 3% when the inclination angle α is about 28 °, and the degree of polarization generated by the folding mirror 5 (aluminum mirror) inclined at 45 ° is almost equal. Offset.

  As shown in FIG. 1, when the folding mirror 5 is arranged at a position where the illumination light IL from the center of the light source 1 is substantially parallel to the optical axis AX, the incident angle to the folding mirror 5 is different even if the illumination position is different. Similar distribution. Therefore, the degree of polarization generated in the folding mirror 5 is about 3% even if the illumination position is different. Further, even if the wavelength of the illumination light IL is different, the wavelength dependence of the degree of polarization is small. Further, the polarization correction plate 8 is positioned between the condenser lens 7 that performs telecentric illumination and the irradiated surface 16 so that the light beam from the center of the exit surface of the fly-eye lens 6 is substantially parallel to the optical axis AX. is there. Therefore, the light beams incident on the polarization correction plate 8 have the same distribution of incident angles even if the illumination positions are different. Further, the wavelength dependence of the degree of polarization by the polarization correction plate 8 (parallel flat plate) is small. Accordingly, it is possible to widen the wavelength range over the entire illumination area of the irradiated surface 16 and reduce the degree of polarization of light (linearly polarized light component generated by reflection) increased by reflection at the folding mirror 5.

  Practically, a polarimeter 57 that can measure the degree of polarization of incident light is installed on the stage 51, and the illumination light is applied from the illumination device 80 to the irradiated surface 16 in a state where the polarimeter 57 is moved into the irradiated surface 16. IL may be irradiated. Then, the angle adjustment mechanism 10 tilts the polarization correction plate 8 so that the degree of polarization measured by the polarimeter 57 is smaller than, for example, 1% (or an allowable value smaller than this), or the degree of polarization is minimized. By adjusting the angle α, the irradiated surface 16 can be illuminated with non-polarized illumination light.

  Next, as a second inspection method in the present embodiment, the wafer 50 placed on the stage 51 of the prober 90 is illuminated with a linearly polarized light beam, for example, in order to measure the polarization characteristics of the inspection target element. In this inspection method, as described above, the inclination angle α of the polarization correction plate 8 is set so that the light beam transmitted through the polarization correction plate 8 becomes non-polarized light, and as shown in FIG. A linear polarizing plate (polarizer) 9 is installed by 20 in the illumination optical path. In this state, the irradiated surface 16 is illuminated with illumination light, and the tester 56 inspects the performance of the inspection target element.

  Furthermore, in order to inspect the polarization characteristics by setting the direction (polarization azimuth angle) of the linearly polarized light of the illumination light applied to the inspection target element to various directions as necessary, the insertion / removal rotation mechanism 20 performs linearly polarized light. The plate 9 is rotated in the θz direction. At this time, in this embodiment, since the illumination light incident on the linearly polarizing plate 9 is non-polarized light, even if the linearly polarizing plate 9 is rotated in the θz direction, the linearly polarized light beam that passes through the linearly polarizing plate 9 is transmitted. The amount of light does not change. Therefore, even if the rotation angle of the linear polarizing plate 9 is set to an arbitrary angle, the amount of light does not change, so that the polarization characteristics of the element to be inspected can be inspected with high accuracy.

The effects and the like of this embodiment are as follows.
The inspection apparatus 100 according to the present embodiment includes an illuminating device 80 that illuminates a solid-state imaging device (irradiated object) on the surface of the wafer 50 on the irradiated surface 16. The illumination device 80 includes a non-polarized light source 1 that generates broadband light, a folding mirror 5 that bends an optical path of light generated from the light source 1, a fly-eye lens 6 on which light from the light source 1 is incident, A polarization correction plate 8 that has transparency to the light and reduces the degree of polarization of the light that is increased by the folding mirror 5, and the polarization correction plate 8 extends from the center of the light exit surface of the fly-eye lens 6. The emitted light is disposed at a position that is substantially parallel to the optical axis AX of the illumination device 80.

According to the illumination device 80, even if the polarization degree of the broadband (white) non-polarized light beam generated from the light source 1 is changed (increased) by the folding mirror 5, the change (increase of the polarization degree) is caused by the polarization correction plate 8. Min) is reduced. Accordingly, a change in the degree of polarization of the non-polarized light beam generated from the light source 1 (increase in the degree of polarization) can be suppressed, and the solid-state imaging device (irradiated surface 16) to be inspected can be illuminated with a wide band and a non-polarized light beam. .

  The polarization correction plate 8 has a surface 8a on which light is incident, and the polarization correction plate 8 has a principal ray of the light (provided in the illumination device 80) with respect to an axis orthogonal to the surface 8a. A light beam that passes through the center of an aperture stop (not shown) (here, an oblique light beam that passes through the center of the exit surface (pupil surface) of the fly-eye lens 6) may intersect and enter the surface 8a. As a result, since the light incident on the polarization correction plate 8 always contains s-polarized light and p-polarized light components, it is possible to correct the change in the degree of polarization of the light reflected by the folding mirror 5. Thus, even if the optical system configured by the illumination device 80 is a decentered optical system, it is possible to correct the change in the degree of polarization of the light reflected by the folding mirror 5 by the polarization correction plate 8.

  Further, the illumination device 80 includes a fly-eye lens 6 for making the illuminance distribution uniform, and the polarization correction plate 8 has a light flux from the center of the exit surface (secondary light source) of the fly-eye lens 6 approximately on the optical axis AX. They are arranged in parallel positions. Accordingly, since the incident angle distribution on the polarization correction plate 8 of the light beam condensed at each position on the illuminated surface 16 is almost uniform regardless of the illumination position, the polarization due to the difference in illumination position on the illuminated surface 16 is achieved. The variation in degree can be reduced.

The polarization correction plate 8 is a plane parallel plate and is easy to manufacture. However, as the polarization correction plate 8, it is also possible to use a wedge-shaped optical member (plate-shaped optical member) such as a wedge-shaped prism having a certain angle between the front surface 8a and the back surface. . In this case, for example, the wedge-shaped optical member is inclined with respect to the optical axis AX with the angle formed by the plane (surface) incident on the wedge-shaped optical member and the plane 15 as the inclination angle α. In this case, it is considered that α is not zero and is inclined with respect to the optical axis.
Moreover, although the relay optical system 4 is provided in this embodiment, the relay optical system 4 can be omitted. Further, the light source 1 does not necessarily have a wide band. For example, when inspecting characteristics of an image sensor with respect to light of a specific wavelength, a light source that generates monochromatic and non-polarized light may be used as the light source 1. In this case, if the mirror is a folding mirror, a linearly polarized light component is hardly generated if a laser mirror having a reflectance close to 100% is used, but it is difficult to prevent a linearly polarized light component from being generated by a beam splitter or the like.

  In addition, the inspection apparatus 100 uses the illumination device 80, the stage 51 on which the inspection object illuminated by the light from the illumination device 80 (solid-state image sensor on the surface of the wafer 50) is placed, and the illumination device 50. And a tester 56 (inspection unit) that detects an output from the illuminated inspection object and inspects the inspection object based on a result of the detection. According to the inspection apparatus 100, since the inspection object (solid-state imaging device) can be illuminated with non-polarized light from the illumination device 80, the inspection can be performed with high accuracy.

  In addition, since the illumination device 80 includes the angle adjustment mechanism 10 that adjusts the inclination angle α of the polarization correction plate 8, for example, when the color filter 3B is replaced, the degree of polarization of the light beam transmitted through the polarization correction plate 8 is minimized. Thus, the inclination angle α can be adjusted. However, since the wavelength dependence of the degree of polarization is small, the tilt angle α of the polarization correction plate 8 can be fixed after being adjusted once. When the tilt angle α is fixed in this way, the polarization correction plate 8 may be supported by a support member having no adjustment mechanism without providing the angle adjustment mechanism 10.

Further, in the present embodiment, the glass material of the polarization correction plate 8 is BK7, so that it is easy to obtain. Actually, the glass material of the polarization correction plate 8 (parallel flat plate) has an advantage that the higher the refractive index, the smaller the inclination angle α, and the easier the arrangement.
FIG. 5 shows the incident angle dependence of the degree of polarization of transmitted light when SF6 (d-line refractive index = 1.805180) is used as the glass material of the polarization correction plate 8. From FIG. 5, when SF6 (heavy flint glass) is used, the incident angle (tilt angle α) for setting the degree of polarization to 3% is approximately 21 °, which is 28 when BK7 (crown glass) is used. Since it becomes smaller than °, the arrangement of the polarization correction plate 8 is easy.

Further, as the position where the polarization correction plate 8 is arranged, the light source 1 (in order to suppress unevenness in the amount of light (inclination unevenness) on the irradiated surface 16 by making the incident angle distribution of light with respect to the surface 8a substantially equal to the polarization correction plate 8. Alternatively, the distribution of the incident angles of the light beams on the polarization correction plate 8 in the positions where the light beams from the center of the secondary light source are substantially parallel to the optical axis AX (or the light beams collected at the respective positions of the irradiated surface 16). Are preferably equal to each other). Therefore, the polarization correction plate 8 is not only between the condenser lens 7 and the irradiated surface 16 as in the present embodiment, but also, for example, the position P1 between the filter group 3 and the relay optical system 4, the relay optical system 4 and It can also be arranged at a position between the folding mirror 5 or a position between the folding mirror 5 and the fly-eye lens 6.

  When the polarization correction plate 8 is disposed at the position P1, the illumination device 80 that illuminates the illuminated surface 16 includes the light source 1 that generates non-polarized light, and the folding mirror 5 that bends the optical path of the light generated from the light source 1. A polarization correction plate 8 that has transparency to the light and that reduces in advance the degree of polarization of the light that is increased by the folding mirror 5, and the polarization correction plate 8 receives light emitted from the center of the light source 1. It is disposed at a position substantially parallel to the optical axis AX of the illumination device 80. Also in this case, the irradiated surface 16 can be illuminated with non-polarized illumination light IL. In this case, the configuration between the folding mirror 5 and the irradiated surface 16 is arbitrary, and it is not always necessary to include an optical integrator.

Moreover, since the illuminating device 80 of this embodiment has the linear polarizing plate 9 supported by the insertion / removal rotation mechanism 20, it can illuminate the irradiated surface 16 with linearly polarized light in an arbitrary direction and the same amount of light. For example, when it is not necessary to inspect the polarization characteristics of the solid-state imaging device, it is not necessary to provide the linearly polarizing plate 9 and the insertion / removal rotation mechanism 20.
In the present embodiment, the degree of polarization of the light incident on the irradiated surface 16 (illumination light from the image sensor) is defined as a state in which non-polarized light can be regarded as having a degree of polarization of 0%. The polarization correction plate 8 may be installed so as to obtain illumination light having a degree of polarization corresponding to a predetermined inspection. For example, the degree of polarization of light incident on the irradiated surface 16 may be about 1%.

  In the above embodiment, a light source (light source 1) that generates non-polarized light having a degree of polarization of approximately 0% is used. However, light having a degree of polarization of not approximately 0% (so-called partially polarized light, polarized light). A light source that generates non-polarized light may be used, or a light source that generates non-polarized light and a predetermined optical member may be used to generate light whose degree of polarization is not nearly 0%. May be. In this case, the inclination angle α of the polarization correction plate 8 is set so that the solid-state imaging device (irradiated surface 16) is illuminated with non-polarized light, and the polarization degree of the light incident on the surface 8a by the polarization correction plate 8 is set. Change.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. In FIG. 6, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 6 shows a schematic configuration of an inspection apparatus 100A according to the present embodiment. The inspection apparatus 100A includes an illuminating device 80A that illuminates a solid-state image sensor (inspection target element) on the surface of the wafer 50, a prober 90 that moves the wafer 50, and a tester that inspects the performance of the inspection target element illuminated by the illuminating device 80A. (Not shown), a main controller 53, and a frame mechanism FR that supports an optical member and the like of the lighting device 80A.

  In the illuminating device 80A, the non-polarized broadband light beam (illumination light IL) emitted from the light source 1 in the substantially + Z direction passes through the collector lens 2, the filter group 3, and the first relay optical system 4A, and passes through the first relay optical system 4A. The optical path is bent approximately 90 ° in the + X direction by the folding mirror 5A, and enters the second relay optical system 4B. The light beam emitted from the relay optical system 4B is incident on the first fly-eye lens 6A after the optical path is bent approximately 90 ° in the −Z direction by the second folding mirror 5B. The light beam emitted from the fly-eye lens 6A passes through the lens 25 and a beam splitter 31 in which a beam splitter surface (Fresnel reflection surface) is formed on one surface of a plane parallel plate inclined approximately 35 ° with respect to the optical axis AX. The light enters the second fly's eye lens 6B. The light beam emitted from the fly-eye lens 6B enters the irradiated surface 16 through the condenser lens 7 and the polarization correction plate 8 inclined with respect to the plane perpendicular to the optical axis AX. The folding mirrors 5A and 5B are flat mirrors similar to the folding mirror 5 of FIG. 1, and the reflecting surfaces of the folding mirrors 5A and 5B are 45 around an axis parallel to the Y axis with respect to the optical axis AX of the illumination device 80A. ° Inclined. The folding mirrors 5A and 5B are respectively arranged at positions where the light beam from the center of the light source 1 is substantially parallel to the optical axis AX. The optical system of the illumination device 80A is composed of optical members from the light source 1 to the polarization correction plate 8.

  The illumination device 80A includes a beam splitter 31, a lens 32 that collects the light beam reflected (branched) by the beam splitter 31, and a light amount monitor system 30 that includes a photoelectric sensor 33 that receives the collected light beam. . Light amount information of the illumination light IL detected by the light amount monitor system 30 is output to the main controller 53. The main controller 53 controls the output of the light source 1 or controls the ND filter so that the illuminance on the irradiated surface 16 becomes a predetermined value based on the light quantity information, for example. The beam splitter 31 of the light quantity monitor system 30 has a light beam from the center of the exit surface (pupil plane or secondary light source) of the fly eye lens 6A between the lens 25 and the fly eye lens 6B substantially parallel to the optical axis AX. It is arranged at the position. The position where the beam splitter 31 is installed in this way is the position where the light beam from the center of the light source 1 or the secondary light source is substantially parallel to the optical axis AX (or the surface of the irradiated surface 16), like the folding mirrors 5A and 5B. It is desirable that the light beam condensed at each point is a position that uniformly includes light beams having the same incident angle distribution.

  Furthermore, the illumination device 80A includes a first rotation mechanism 35 that integrally rotates the fly-eye lenses 6A and 6B, the lens 25, the beam splitter 31, the lens 32, and the photoelectric sensor 33 in the θz direction, the polarization correction plate 8 and The angle adjusting mechanism 10 has a second rotating mechanism 40 that integrally rotates in the θz direction. For example, the rotation mechanism 35 rotates the support member 36 with respect to the frame mechanism FR via the gear mechanism 39 and the support member 36 that holds the optical member to be rotated via the bearing 37 with respect to the frame mechanism FR. Drive motor 38. Similarly, the rotation mechanism 40 includes a support member 41 that holds the angle adjustment mechanism 10 and the polarization correction plate 8 via a bearing 42 with respect to the frame mechanism FR, and a gear mechanism 44 that supports the support member 41 with respect to the frame mechanism FR. And a drive motor 43 that rotates via the motor. The main controller 53 controls the rotation angle of the support members 36 and 41 via the drive motors 38 and 43.

  Next, FIG. 7A shows a plurality of rectangular solid-state imaging devices 58 (the length a1 in the X direction and the width b1 in the Y direction) aligned on the surface of the wafer 50 of the present embodiment (FIG. 6). An example of the arrangement is shown. In FIG. 7A, the width of one side of the illuminated area 59 of FIG. Further, when the solid-state imaging device 58 is inspected by a tester (not shown), it is possible to inspect a plurality of solid-state imaging devices 58A to 58D, etc., which are arranged every other one in the Y direction as shown by hatching. To do. At this time, as an example, if the length a1 of the solid-state imaging device 58 is 9.8 mm, the width b1 is 7.6 mm, and the width A1 of the illumination area 59 is 44.6 mm, the illumination area 59 is indicated by a dotted line position 59A. Thus, when each side is arranged in parallel to the X axis or the Y axis, there are three solid-state image sensors 58A to 58C that can be inspected at a time.

  On the other hand, in the present embodiment, the fly eye lenses 6A, 6B and the like are rotated in the θz direction by the first rotation mechanism 35 of FIG. As shown by a solid line (here, at an angle inclined by 45 ° with respect to the X axis), it can rotate. In this state, since the four solid-state image sensors 58A to 58D enter the illumination area 59, the four solid-state image sensors 58 can be inspected at a time. In the case where the rotating mechanism 35 is not provided, in order to inspect four solid-state imaging devices 58 at a time, a wide illumination area 60 having a width A2 of, for example, 53.2 mm is required as shown in FIG. 7B. This increases the size of the lighting device.

Thus, in the present embodiment, since the rotation mechanism 35 is provided, more solid-state imaging devices can be inspected at a time without widening the illumination area 59 of the irradiated surface 16.
In the present embodiment, since the so-called double fly-eye configuration using the two-stage fly-eye lenses 6A and 6B is used, the uniformity of the illuminance distribution on the irradiated surface 16 is improved. Furthermore, by using the two folding mirrors 5A and 5B, the illuminating device 80A can be reduced in size even when the double-stage relay optical systems 4A and 4B are used in a double fly-eye configuration.

  However, two folding mirrors 5A and 5B are used, and the reflection surface of the second folding mirror 5B is parallel to a surface obtained by rotating the reflection surface of the first folding mirror 5A by 180 ° around the optical axis AX. is there. In other words, the light incident surfaces (XZ surfaces) along the optical axis of the folding mirrors 5A and 5B are parallel to each other. Further, from the description of the first embodiment, the reflection mirrors 5A and 5B both have high reflectivity with respect to light of s-polarized light (polarized light in the Y direction), so the degree of polarization of the light beam reflected by the reflection mirror 5B is It is almost twice as bad as in the first embodiment. Furthermore, in the present embodiment, the degree of polarization is also changed by the beam splitter 31 of the light amount monitor system 30 arranged in the illumination optical path. However, since the transmittance of the p-polarized light is usually high in the beam splitter 31, for example, the beam splitter 31 is inclined at, for example, approximately 35 ° in the θy direction with respect to the optical axis AX as shown in the arrangement of FIG. The degree of polarization of the light beam transmitted through the beam splitter 31 is substantially smaller than the degree of polarization of the light beam immediately after being reflected by the folding mirror 5B.

  However, in this embodiment, in order to rotate the illumination area 59 of the irradiated surface 16, the fly-eye lenses 6A and 6B and the beam splitter 31 are integrally rotated by the rotation mechanism 35. As a result, depending on the rotation angle of the beam splitter 31, the degree of polarization of the light beam after passing through the beam splitter 31 changes in a complicated manner, and the degree of polarization is higher than the degree of polarization of the light beam after being reflected by the folding mirror 5B. It can be.

  Therefore, in this embodiment, in order to reduce the degree of polarization of the light beam that has passed through the beam splitter 31, the inclination angle α with respect to the plane perpendicular to the optical axis AX can be adjusted between the condenser lens 7 and the irradiated surface 16. And a polarization correction plate 8 capable of adjusting the rotation angle in the θz direction. In the present embodiment, since the degree of polarization of the light beam incident on the polarization correction plate 8 may be higher than that in the first embodiment, in order to reduce the tilt angle α of the polarization correction plate 8, The correction plate 8 is preferably a plane parallel plate made of, for example, SF6 having a higher refractive index.

  As an example, before the use of the inspection apparatus 100A is started, a polarimeter 57 that can measure the degree of polarization of incident light is installed on the stage 51, the polarimeter 57 is moved into the irradiated surface 16, and light emission of the light source 1 is started. The main controller 53 rotates the fly-eye lenses 6A and 6B, the beam splitter 31 and the like via the rotation mechanism 35 in the θz direction by 180 ° / N (N is an integer of 4 or more, for example). The rotation angle and the inclination angle α of the polarization correction plate 8 are adjusted by the rotation mechanism 40 and the angle adjustment mechanism 10 so that the measured value of the polarization degree to be measured is smaller than the predetermined allowable value or the minimum value. Specifically, θz is adjusted so that the linear polarization direction or the elliptical polarization long axis direction of the polarimeter measurement result when the inclination angle α of the polarization correction plate 8 is 0 is s-polarized light, and then the inclination angle α is polarized. The measurement value of the degree is adjusted to be smaller than a predetermined allowable value or to a minimum value. If necessary, the fine adjustment of the rotation angle and the inclination angle α in the θz direction of the polarization correction plate 8 is repeated. Then, the rotation angle of the polarization correction plate 8 by the rotation mechanism 40 and the tilt angle α of the polarization correction plate 8 by the angle adjustment mechanism 10 are stored in correspondence with the rotation angle by the rotation mechanism 35. Thereafter, the beam splitter 31 or the like is further rotated 180 ° / N in the θz direction via the rotation mechanism 35, and the polarization correction plate when the measured value of the polarization degree becomes smaller than the predetermined allowable value or becomes the minimum value. The operation of obtaining and storing the rotation angle 8 and the inclination angle α is repeated until the rotation angle by the rotation mechanism 35 reaches 180 °. Ideally, the state rotated by 180 ° by the rotation mechanism 35 is the same polarization state as before rotation, so the rotation angle range of the rotation mechanism 35 is 0 ° to 180 ° (−90 ° to 90 °), but 180 Instead of rotating, it may be rotated 360 °. Since the rotation of the illumination field is 90 ° when the illumination field is square, the rotation angle range of the rotation mechanism 35 may be 0 ° to 90 ° (−45 ° to 45 °).

  Thereafter, when the solid-state imaging device on the surface of the wafer 50 is inspected using the inspection apparatus 100A, when the illumination area 59 of the irradiated surface 16 is rotated via the rotation mechanism 35, the irradiated surface is selected according to the rotation angle. The rotation angle and the inclination angle α of the polarization correction plate 8 are adjusted via the rotation mechanism 40 and the angle adjustment mechanism 10 so that the degree of polarization on the surface 16 is reduced. Accordingly, when white and non-polarized illumination light IL is used, even if the illumination area 59 is rotated in an arbitrary direction, the light beam applied to the illumination area 59 can be made non-polarized. In this embodiment, the folding mirrors 5A and 5B and the beam splitter 31 correspond to the optical member 1.

  The illumination device 80A that illuminates the illuminated surface 16 includes a light source 1 that generates non-polarized light, a fly-eye lens 6B that receives light from the light source 1, and a beam that bends part of the light from the light source 1. A splitter 31, a condenser lens 7 that performs Koehler illumination of the irradiated surface 16 in a substantially telecentric manner with light from the light exit surface of the fly-eye lens 6 </ b> B, and the condenser lens 7 and the irradiated surface 16. And a polarization correction plate 8 made of a plane parallel plate that reduces the degree of polarization of light that is increased by the folding mirrors 5A and 5B and the beam splitter 31. According to the illumination device 80A, the illuminated surface 16 can be illuminated with non-polarized light. In this case, the folding mirrors 5A and 5B are not necessarily provided.

  In the present embodiment, the polarization correction plate 8 may be disposed at a position where the light beam from the center of the light source 1 is substantially parallel to the optical axis AX. In the present embodiment, even when the folding mirrors 5A and 5B are not provided, the degree of polarization generated by the beam splitter 31 of the light quantity monitor system 30 can be corrected by providing the polarization correction plate 8.

  Also in this embodiment, a light source that generates light whose polarization degree is not nearly 0% (so-called partially polarized light, polarization degree of about 10% to 10%) may be used, or unpolarized light is used. A configuration in which light having a degree of polarization not substantially 0% may be generated by combining a light source to be generated and a predetermined optical member. In this case, the rotation angles in the tilt angles α and θz directions of the polarization correction plate 8 are set so that the solid-state imaging device (irradiated surface 16) is illuminated with non-polarized light, and the polarization correction plate 8 causes the surface 8a. The degree of polarization of incident light is changed.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG. In FIG. 8, portions corresponding to those in FIGS. 1 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 8 shows a schematic configuration of the illumination device 80B according to the present embodiment. The illumination device 80B can be used as, for example, the illumination device of the inspection device 100 in FIG.

  In the illumination device 80B, the non-polarized broadband light beam (illumination light IL) emitted from the light source 1 in the substantially + Y direction passes through the collector lens 2, the filter group 3, and the first relay optical system 4A, and the first relay optical system 4A. The optical path is bent approximately 90 ° in the + X direction by the folding mirror 5A, and enters the second relay optical system 4B. The light beam emitted from the relay optical system 4B is incident on the fly-eye lens 6 after the optical path is bent approximately 90 ° in the −Z direction by the second folding mirror 5C. The light beam emitted from the fly-eye lens 6 enters the irradiated surface via the condenser lens 7. An optical system of the illumination device 80B is composed of optical members from the light source 1 to the condenser lens 7.

  In this embodiment, the folding mirrors 5A and 5C are plane mirrors similar to the folding mirror 5 in FIG. 1, but the reflecting surface 5Aa of the folding mirror 5A is θz with respect to the optical axis parallel to the Y axis of the illumination device 80B. The reflecting surface 5Ca of the folding mirror 5C is inclined 45 ° around an axis parallel to the Y axis with respect to the optical axis parallel to the X axis of the illumination device 80B. In other words, the reflecting surface 5Ca of the second folding mirror 5C is parallel to a surface obtained by rotating the reflecting surface 5Aa of the first folding mirror 5A by 90 ° clockwise around the optical axis AX. As a result, with respect to the light flux parallel to the optical axis AX, the incident surface (XY surface) of the folding mirror 5A and the incident surface (XZ surface) of the folding mirror 5C intersect perpendicularly. (Or p-polarized light) becomes p-polarized light (or s-polarized light) with respect to the folding mirror 5C.

  In the present embodiment, from the description of the first embodiment, the reflection mirror 5A has a higher reflectance with respect to light of s-polarized light (here, polarization in the Z direction), but the light of s-polarized light is p in the reflection mirror 5C. It becomes polarized light and the reflectance becomes small. That is, a change in the degree of polarization of the light beam reflected by the folding mirror 5A (an increase in the degree of polarization) is reduced by reflection at the folding mirror 5C. Accordingly, the illumination device 80B can be miniaturized using the two folding mirrors 5A and 5C, and the change in the degree of polarization of the non-polarized light beam generated from the light source 1 (increase in the degree of polarization) can be suppressed. Can be illuminated with a broadband and non-polarized light beam.

  Further, in the case where the degree of polarization of light generated by the folding mirrors 5A and 5C and other optical members is further suppressed, the polarization correction plate 8 can be used as in the first and second embodiments. . In this case, the polarization correction plate 8 is disposed obliquely with respect to a plane perpendicular to the optical axis AX of the optical system of the illumination device 80B, between the condenser lens 7 of the illumination device 80B and the irradiated surface 16.

  The inclination angle α with respect to the plane perpendicular to the optical axis AX of the polarization correction plate 8 is based on the magnitude of the linearly polarized light component incident on the irradiated surface, and the light incident on the irradiated surface 16 is as non-polarized as possible. Decide to be a light. The rotation angle of the polarization correction plate 8 in the θz direction is determined based on the direction of the linearly polarized light component of the light incident on the irradiated surface.

  The illumination device 80B has an angle adjustment mechanism (not shown) and adjusts the tilt angle α of the polarization correction plate 8 and the rotation angle of the polarization correction plate 8 in the θz direction. Note that the inclination angle α of the polarization correction plate 8 and the rotation angle of the polarization correction plate 8 in the θz direction can be fixed once adjusted.

  Note that the polarization correction plate 8 is not only between the condenser lens 7 and the irradiated surface 16 but also at a position between, for example, the filter group 3 and the first relay optical system 4A, or folded with the first relay optical system 4A. A position between the mirror 5A, a position between the folding mirror 5A and the second relay optical system 4B, a position between the second relay optical system 4B and the folding mirror 5B, or a folding mirror 5B and a fly-eye lens. It can also be arranged at a position between 6.

In the present embodiment, the reflecting surface 5Ca of the second folding mirror 5C is parallel to a surface obtained by rotating the reflecting surface 5Aa of the first folding mirror 5A by 90 ° clockwise around the optical axis AX. The degree of polarization generated in the folding mirror 5A can be reduced most favorably. However, the reflecting surface 5Ca of the second folding mirror 5C may be parallel to a surface obtained by rotating the reflecting surface 5Aa of the first folding mirror 5A around the optical axis AX at an angle other than 90 °. Even in this case, the polarization correction plate 8 can reduce the degree of polarization of light incident on the irradiated surface 16.
In each of the above embodiments, a fly-eye lens is used as the optical integrator. However, as the optical integrator, a rod integrator or a combination of a rod integrator and a fly-eye lens can be used.

  Next, an example of a method for manufacturing an image sensor (solid-state image sensor) using the inspection apparatus 100 or 100A of the above embodiment will be described with reference to the flowchart of FIG. In step S401 (pattern formation process) in FIG. 9, first, an image is picked up using an exposure apparatus (not shown), an application process in which a photoresist is applied to a wafer to be exposed (wafer 50 in FIG. 1) to prepare a photosensitive substrate. A predetermined resist pattern is formed on the wafer by a photolithographic process including an exposure process in which an element mask pattern is transferred and exposed to a number of pattern forming regions on the photosensitive substrate, and a developing process in which the photosensitive substrate is developed. The Subsequent to this photolithography process, a circuit pattern of a large number of solid-state imaging devices including a large number of electrodes and the like is formed on the wafer through an etching process, a CVD process, a resist stripping process, and the like using the resist pattern as a mask. The The photolithography process or the like is executed a plurality of times according to the number of layers on the wafer.

  In the next step S402 (color filter forming step), a large number of three fine filter groups corresponding to red R, green G, and blue B are arranged in a matrix or red R, green G, and blue B are arranged. By arranging a set of three stripe-shaped filters in the horizontal scanning line direction, a color filter is formed corresponding to a large number of pixels of a large number of solid-state imaging elements on the wafer surface. In the next step S403 (inspection process), performance inspection of a large number of solid-state imaging devices on the wafer surface is performed using the inspection apparatuses 100 and 100A of the above-described embodiment.

In subsequent step S404 (module assembly process), the element that has passed the inspection in this manner is separated from the wafer, attached to a protective substrate, etc., and further, lead terminals and the like are attached to complete the solid-state imaging element.
According to the above-described method for manufacturing an image sensor, the process includes a step of inspecting a solid-state image sensor using the inspection apparatus of the above-described embodiment, and the inspection apparatus uses a non-polarized inspection light or a light amount regardless of the polarization direction. Since uniform inspection light with linearly polarized light can be used, performance inspection of the manufactured solid-state imaging device can be performed with high accuracy. Therefore, a high-performance solid-state image sensor can be manufactured.

  In the method of manufacturing the image sensor (solid-state image sensor) in FIG. 9, the solid-state image sensor is used in step 403 (inspection process) after step 402 (color filter forming process) using the inspection apparatuses 100 and 100A of the above embodiment. However, the performance inspection of the solid-state imaging device is not limited to after step 402 (color filter forming process), and for example, step 401 (pattern forming process) and step 402 (color filter forming process) You may carry out between.

  In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

  DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Collector lens, 3 ... Filter group, 4, 4A, 4B ... Relay optical system, 5, 5A-5C ... Folding mirror, 6, 6A, 6B ... Fly eye lens, 7 ... Condenser lens, 8 ... Polarization correction plate, 9 ... linearly polarizing plate, 10 ... angle adjustment mechanism, 16 ... irradiated surface, 20 ... insertion / removal rotation mechanism, 50 ... wafer (semiconductor wafer), 56 ... tester, 58 ... solid-state imaging device, 80, 80A , 80B ... lighting device, 90 ... prober, 100,100A ... inspection device

Claims (8)

In an inspection device for inspecting an object to be inspected,
A first optical member on which light generated from a light source enters;
A second optical member having transparency to the light and changing a degree of polarization of the light so that non-polarized light is incident on the inspection object;
Detecting an output from the inspection object illuminated with light from the illumination device, and inspecting the inspection object based on a result of the detection; and
With
The second optical member is disposed at a position where the light emitted from the center of the light source is substantially parallel to the optical axis of the illumination device ,
2. The inspection apparatus according to claim 1, wherein the second optical member includes a plate-like optical member and is inclined with respect to a plane perpendicular to the optical axis of the illumination device. The inspection apparatus according to claim 1 , wherein the plate-like optical member has a variable inclination angle with respect to a plane perpendicular to the optical axis of the illumination apparatus in an arbitrary direction. Wherein the first optical member inspection apparatus according to claim 1 or 2, characterized in that it comprises a beam splitter. The lighting device includes:
An optical integrator on which light from the light source is incident;
Inspection apparatus according to any one of claims 1 to 3, further comprising a, a condenser lens for Kohler illumination in a substantially telecentric light to the inspection object from the exit surface of the light in the optical integrator . In an inspection device for inspecting an inspection object,
A first optical member on which light generated from a light source enters;
A second optical member having transparency to the light and changing a degree of polarization of the light so that non-polarized light is incident on the inspection object;
Detecting an output from the inspection object illuminated with light from the illumination device, and inspecting the inspection object based on a result of the detection; and
With
The second optical member is disposed at a position where the light emitted from the center of the light source is substantially parallel to the optical axis of the illumination device ,
The lighting device includes:
An optical integrator on which light from the light source is incident;
An inspection apparatus further comprising: a condenser lens that irradiates light from the light exit surface of the optical integrator to the object to be inspected approximately telecentricly . The inspection apparatus according to claim 4, wherein the second optical member is disposed between the light source and the optical integrator.   The inspection apparatus according to claim 1, wherein the illumination device further includes the light source, and further includes a stage on which the inspection object is placed. The manufacturing method of an image pick-up element characterized by including the process of test | inspecting an image pick-up element with the test | inspection apparatus as described in any one of Claims 1-7.

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