Patent ID: 12235433

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that in the following description, the same reference numerals will be used for the same or equivalent elements, and duplicate description will be omitted.

[Configuration of Semiconductor Inspection Device]

A semiconductor inspection device100illustrated inFIG.1is a device that acquires an image of a semiconductor device (observation object) S and inspects internal information of the semiconductor device S. The semiconductor device S is formed, for example, by incorporating a plurality of elements on a silicon substrate. That is, the semiconductor device S includes the silicon substrate. The semiconductor device S is, for example, an individual semiconductor element (discrete), an optoelectronic element, a sensor/actuator, a logic LSI (Large Scale Integration), a memory element, a linear IC (Integrated Circuit), or a mixed device thereof. The individual semiconductor element includes a diode, a power transistor, etc. The logic LSI includes a transistor having a MOS (Metal-Oxide-Semiconductor) structure, a transistor having a bipolar structure, etc. Further, the semiconductor device S may be a package including the semiconductor device, a composite substrate, etc.

The internal information to be inspected includes information on a circuit pattern of the semiconductor device S, information on weak light emission from the semiconductor device S (light emission due to a defect in the semiconductor device S, transient light emission due to switching operation of a transistor in the semiconductor device S, etc.), information on heat generation due to a defect in the semiconductor device, etc. As illustrated inFIG.2, the semiconductor device S may be molded by a resin M so that a surface Sa is exposed, and may form a molded semiconductor device. The surface Sa is a surface on the opposite side from the device (integrated circuit, etc.) side in the semiconductor device S, and is, for example, a flat surface.

An image acquired by the semiconductor inspection device100may include an OBIC (Optical Beam Induced Current) image, a LADA (Laser Assisted Device Alteration) image, and a TR-LADA (Time Resolved Laser Assisted Device Alteration) image. The OBIC image is obtained by detecting a photogenic current generated by a laser beam as a characteristic value (current value or current change value) of an electric signal, and imaging the characteristic value in association with laser irradiation position information. The LADA image is acquired by scanning laser light in a state where a test pattern is applied to the semiconductor device S to detect a malfunction state, thereby imaging malfunction information as multi-valued correct/incorrect information for a laser irradiation position on the semiconductor device S. The TR-LADA image is acquired by synchronizing a pulse laser irradiating the semiconductor device S with a test pattern applied to the semiconductor device S to image malfunction information at a specific timing.

As illustrated inFIG.1, the semiconductor inspection device100includes an observation unit110, a control unit120, an analysis unit130, and a display device140. The observation unit110observes the semiconductor device S. The control unit120controls an operation of the observation unit110. The analysis unit130performs processing, instructions, etc. necessary for inspecting the semiconductor device S. The display device140is electrically connected to the analysis unit130, and displays images, data, etc. acquired or analyzed by the analysis unit130. The display device140is, for example, a display.

The observation unit110includes a stage111, an optical system112, a two-dimensional camera (photodetector)113, a moving mechanism114, and an LSM (Laser Scanning Microscope) unit115. The semiconductor device S is placed on the stage111with the surface Sa facing the optical system112side. The moving mechanism114moves the optical system112, the two-dimensional camera113, and the LSM unit115.

The optical system112includes a plurality of objective lenses150, a camera optical system112a, and an LSM unit optical system112b. The magnifications of the respective objective lenses150are different from each other. Each of the objective lenses150is disposed to face the surface Sa of the semiconductor device S placed on the stage111. As illustrated inFIG.2, a correction ring152and a correction ring adjustment motor153are attached to the objective lens150. By driving the correction ring adjustment motor153to adjust the correction ring152, the objective lens150can be reliably focused on a portion desired to be observed.

As illustrated inFIG.1, the camera optical system112aguides light from the semiconductor device S to the two-dimensional camera113. The two-dimensional camera113detects light guided by the camera optical system112a(light passing through the optical system112). The two-dimensional camera113can output image data for creating an image such as the circuit pattern of the semiconductor device S. For example, a CCD area image sensor, a CMOS area image sensor, etc. are mounted on the two-dimensional camera113. The two-dimensional camera113may be, for example, an InGaAs camera, an InSb camera, an MCT camera, etc.

The LSM unit optical system112bguides laser light output from the LSM unit115to the semiconductor device S, and guides laser light reflected by the semiconductor device S to the LSM unit115. The LSM unit optical system112bhas an optical scanning unit such as a galvano mirror, a polygon mirror, or a MEMS mirror, and scans laser beam with respect to the semiconductor device S. The LSM unit115emits laser light generated by a light source, and detects laser light reflected by the semiconductor device S using the photodetector115a.

The light source may generate, for example, CW (Continuous Wave) light or pulsed light that irradiates the semiconductor device S. Light generated by the light source may be not only coherent light such as laser light but also incoherent (non-coherent) light. As a light source that outputs coherent light, it is possible to use a solid-state laser light source, a semiconductor laser light source, etc. Further, as a light source that outputs incoherent light, it is possible to use an SLD (Super Luminescent Diode), ASE (Amplified Spontaneous Emission), an LED (Light Emitting Diode), etc.

The light source may output light in a wavelength range not absorbed by the semiconductor device S. For example, when the semiconductor device S includes a silicon substrate, the light source may output light of 1,300 nm or more. When acquiring the above-mentioned OBIC image, LADA image, or TR-LADA image, the light source may output light in a wavelength range in which electric charges are generated by light absorption in the semiconductor device S. For example, when the semiconductor device S includes a silicon substrate, the light source may output light in a wavelength range of 1,100 nm or less or 1,200 nm or less (for example, laser light in a wavelength band of about 1,064 nm).

The photodetector115ais, for example, an avalanche photodiode, a photodiode, a photomultiplier tube, a superconducting single photon detector, etc. The intensity of laser light detected by the photodetector115areflects the circuit pattern of the semiconductor device S. Therefore, the photodetector115acan output image data for creating an image such as a circuit pattern of the semiconductor device S.

The control unit120includes a camera controller121, an LSM controller122, and a peripheral controller123. The camera controller121is electrically connected to the two-dimensional camera113. The LSM controller122is electrically connected to the LSM unit115. The camera controller121and the LSM controller122control operations of the two-dimensional camera113and the LSM unit115, respectively, to control execution of observation of the semiconductor device S (acquisition of an image), setting of an observation condition of the semiconductor device S, etc.

The peripheral controller123is electrically connected to the moving mechanism114. The peripheral controller123controls the operation of the moving mechanism114to control movements of the optical system112, the two-dimensional camera113, and the LSM unit115, alignment thereof, etc. The peripheral controller123is electrically connected to the correction ring adjustment motor153(seeFIG.2). The peripheral controller123controls drive of the correction ring adjustment motor153to control adjustment of the correction ring152(seeFIG.2).

The analysis unit130includes an image analysis unit131and an instruction unit132. The analysis unit130includes a computer having a processor (CPU), and a RAM and a ROM as recording media. The analysis unit130is electrically connected to each of the camera controller121, the LSM controller122, and the peripheral controller123. The image analysis unit131creates an image based on image data output from each of the camera controller121and the LSM controller122, and executes analysis processing, etc. The instruction unit132refers to input content by an operator, analysis content by the image analysis unit131, etc., and gives an instruction to the control unit120with regard to execution of inspection of the semiconductor device S by the observation unit110. An operation unit (not illustrated) is electrically connected to the analysis unit130. A user operates the operation unit to operate the semiconductor inspection device100. The operation unit is, for example, a mouse, a keyboard, etc. Further, the operation unit may be, for example, a touch panel built in the display device140.

[Configuration of Solid Immersion Lens Unit]

The optical system112further includes a solid immersion lens unit1in addition to the above-mentioned objective lenses150, etc. As illustrated inFIG.2, the solid immersion lens unit1includes a solid immersion lens2, a holder3, and a support mechanism4. In the following description, in a state where the objective lens150faces the surface Sa of the semiconductor device S placed on the stage111, a side where the objective lens150is located with respect to the semiconductor device S is set to an upper side, and a side where the semiconductor device S is located with respect to the objective lens150is set to a lower side.

The holder3swingably holds the solid immersion lens2. The holder3has a side wall31, a bottom wall32, and a support member33. The side wall31has a tubular shape. The bottom wall32is integrally formed with the side wall31so as to close an opening on a lower side of the side wall31. The support member33is attached to the bottom wall32from a lower side. The side wall31, the bottom wall32, and the support member33are made of a non-magnetic material (for example, aluminum, aluminum alloy, non-magnetic stainless steel, etc.).

The support mechanism4movably supports the holder3in a direction parallel to an optical axis L of the objective lens150. The support mechanism4has an attached member41, a plurality of linear guides42, and a plurality of compression coil springs43. The attached member41has a tubular shape and is attached a lower end151aof a lens barrel151of the objective lens150. The plurality of linear guides42is disposed between an outer surface of the attached member41and an inner surface of the side wall31of the holder3. The plurality of linear guides42is disposed at equal pitches around the optical axis L. The plurality of compression coil springs43is disposed between a lower end surface of the attached member41and an upper surface of the bottom wall32of the holder3. The plurality of compression coil springs43is disposed around the optical axis L at equal pitches. In this way, when an external force is applied to the holder3from the lower side, the holder3moves upward from an initial position against an urging force of the plurality of compression coil springs43, and when the external force is removed from the holder3, the holder3returns to the initial position by the urging force of the plurality of compression coil springs43.

[Configuration of Solid Immersion Lens]

As illustrated inFIG.3, the solid immersion lens2has a first lens portion21and a second lens portion22. The first lens portion21includes a contact surface21a, a first tapered surface21b, and a first spherical surface21c. The contact surface21ais a flat surface and is brought into contact with the surface Sa of the semiconductor device S. The first tapered surface21bis a truncated cone-shaped surface that extends upward, and extends upward from an outer edge of the contact surface21a. The first spherical surface21cis a convex and hemispherical surface curved toward the upper side, and extends from an edge of the first tapered surface21bso as to oppose the contact surface21a. An outer diameter of the first lens portion21is, for example, about 1.5 mm to 2.0 mm. A center of curvature of the first spherical surface21cand an apex of a virtual cone including the first tapered surface21bcoincide with a spherical center C of the solid immersion lens and are located on the optical axis L below the contact surface21a. The spherical center C of the solid immersion lens coincides with a focal point of the solid immersion lens2.

The second lens portion22includes a second spherical surface22a, a second tapered surface22b, a third spherical surface22c, and a peripheral surface22d. The second spherical surface22ais a concave and hemispherical surface curved toward the upper side. The second spherical surface22afaces the first spherical surface21cof the first lens portion21and extends along the first spherical surface21c. The second tapered surface22bis a truncated cone-shaped surface that extends upward, and extends upward from the outer edge of the second spherical surface22a. The second tapered surface22bis flush with the first tapered surface21band forms one truncated cone-shaped surface together with the first tapered surface21b. The third spherical surface22cis a convex and hemispherical surface curved toward the upper side, and is disposed to face the objective lens150. The peripheral surface22dis a cylindrical surface, and is connected to an outer edge of the second tapered surface22band an outer edge of the third spherical surface22c. Centers of curvature of the second spherical surface22aand the third spherical surface22ccoincide with the center of curvature of the first spherical surface21c(the spherical center C of the solid immersion lens). An apex of a virtual cone including the second tapered surface22bcoincides with the spherical center C of the solid immersion lens.

Since the first lens portion21has the first tapered surface21b, the contact surface21aof the first lens portion21projects downward (opposite side from the objective lens150) with respect to the second lens portion22in a direction parallel to the optical axis L of the objective lens150. In other words, in the solid immersion lens2, the contact surface21ais located on a lowermost side, and a boundary between the first lens portion21and the second lens portion22is not located on a plane on which the contact surface21ais disposed.

The first lens portion21is formed of a first material having a refractive index substantially equal to or close to a refractive index of a substrate material (silicon (Si) in this example) of the semiconductor device S. The first material is, for example, Si, GaP (gallium phosphide), GaAs (gallium arsenide), Ge (germanium), diamond, SiC, or GaN (gallium nitride). The refractive indexes of Si, GaP, GaAs, Ge, diamond, SiC, and GaN are 3.5, 3.2, 3.5, 4.0, 2.4, 2.6, and 2.4, respectively. The second lens portion22is formed of a second material having a refractive index larger than a refractive index of air (atmosphere) and smaller than the refractive index of the first material. The second material is, for example, glass, polymer, sapphire, quartz, calcium fluoride, magnesium fluoride, etc. The refractive indexes of glass, polymer, sapphire, quartz, calcium fluoride, and magnesium fluoride are 1.5 to 2.0, 1.5 to 1.6, 1.8, 1.5, 1.4, and 1.4, respectively.

The first lens portion21and the second lens portion22are coupled to each other by an adhesive provided between the first spherical surface21cand the second spherical surface22a. The first lens portion21and the second lens portion22are bonded so that the centers of curvature of the first spherical surface21c, the second spherical surface22a, and the third spherical surface22ccoincide with each other. The adhesive is provided over the entire surface of, for example, the first spherical surface21cand the second spherical surface22a. As the adhesive, it is possible to use an adhesive having a refractive index closer to the refractive index of the second material than the refractive index of the first material. In this way, light is easily transmitted through the solid immersion lens2. A first antireflection film (AR coating) may be provided between the first spherical surface21cand the adhesive. The first antireflection film is provided, for example, over the entire surface of the first spherical surface21c. A second antireflection film may be provided on the third spherical surface22c. The second antireflection film is provided, for example, over the entire surface of the third spherical surface22c.

[Holding Structure of Solid Immersion Lens]

As illustrated inFIG.2, the solid immersion lens2is held by the holder3so as to be located on the optical axis L on the lower side (front side) of the objective lens150. As illustrated inFIGS.4and5, an opening32ais formed in the bottom wall32. A shape of the opening32awhen viewed from a direction parallel to the optical axis L is, for example, a circular shape with the optical axis L as a center line, and an inner diameter thereof is smaller than an outer diameter of the solid immersion lens2(outer diameter of the peripheral surface22d). A plurality of protrusions34is provided on an edge of the opening32a. The plurality of protrusions34extends from the edge of the opening32atoward a center of the opening32a. The plurality of protrusions34is integrally formed with the bottom wall32by a non-magnetic material. The plurality of protrusions34is disposed around the optical axis L at equal pitches. In the present embodiment, three protrusions34are disposed around the optical axis L at a pitch of 120°.

The support member33has an annular shape, and is attached to the bottom wall32from the lower side, for example, by being screwed to each of the protrusions34. A shape of an opening of the support member33when viewed from a direction parallel to the optical axis L is, for example, a circular shape with the optical axis L as a center line, and an inner diameter thereof is slightly larger than the outer diameter of the solid immersion lens2. An inward flange33ais integrally formed at a lower end of the support member33. A shape of an opening of the inward flange33awhen viewed from a direction parallel to the optical axis L is, for example, a circular shape with the optical axis L as a center line, and an inner diameter thereof is smaller than the outer diameter of the solid immersion lens2.

The solid immersion lens2is disposed so that the contact surface21aprotrudes downward from the opening of the inward flange33aand the peripheral surface22dis located inside the opening of the support member33. In this state, since the inner diameter of the opening of the support member33is slightly larger than the outer diameter of the solid immersion lens2, while movement of the solid immersion lens2in a direction perpendicular to the optical axis L is restricted, movement of the solid immersion lens2in the direction parallel to the optical axis L and swing of the solid immersion lens2(for example, moving to tilt by about 1° with respect to the optical axis L) are allowed. Further, since the inner diameter of the opening of the inward flange33ais smaller than the outer diameter of the solid immersion lens2, the solid immersion lens2is prevented from falling off to the lower side.

A plurality of accommodating holes36is formed on the upper surface of the bottom wall32. The plurality of accommodating holes36is disposed to correspond to the plurality of protrusions34, respectively. A magnet5is accommodated in each of the accommodating holes36. Each magnet5has, for example, a cylindrical shape, and a center line thereof is directed toward the spherical center C of the solid immersion lens2. As described above, the holder3is provided with a plurality of magnets5.

An inclined surface34ais formed on each protrusion34. Each inclined surface34afaces the third spherical surface22cof the solid immersion lens2. An accommodating portion35is formed on each inclined surface34a. Each accommodating portion35is, for example, a cylindrical recess. The magnet5is provided in the holder3to face a central portion of the accommodating portion35. For example, a center line of the accommodating portion35coincides with the center line of the magnet5accommodated in the corresponding accommodating hole36. The bottom surface35aof each accommodating portion35is a flat surface and faces the third spherical surface22cof the solid immersion lens2. A side surface35bof each accommodating portion35has a cylindrical shape. A distance between the bottom surface35aand the inclined surface34a(that is, a height of the side surface35b) is smaller than a diameter of a sphere6. As described above, the holder3is provided with a plurality of accommodating portions35.

Each accommodating portion35accommodates the sphere6. Each sphere6functions as a contact portion40in contact with the third spherical surface22cof the solid immersion lens2. Each sphere6is made of a magnetic material (for example, nickel, cobalt, iron, stainless steel, etc.). In each accommodating portion35, the sphere6is rotatably held at a center of the bottom surface35a(position facing the third spherical surface22cof the solid immersion lens2) by a magnetic force of the magnet5accommodated in the corresponding accommodating hole36. In this state, a part of the sphere6protrudes from the accommodating portion35. In the present embodiment, three spheres6are disposed around the optical axis L at a pitch of 120°.

As illustrated inFIG.4, in a state where an outer edge of the second tapered surface22bof the solid immersion lens2is in contact with the inward flange33aof the support member33, a gap is formed between the third spherical surface22cof the solid immersion lens2and each sphere6. In this way, when the solid immersion lens2moves upward, the third spherical surface22cof the solid immersion lens2comes into contact with the plurality of spheres6. Therefore, while the solid immersion lens2is prevented from moving further upward, the solid immersion lens2is allowed to swing. As described above, the holder3swingably holds the solid immersion lens2in a state where the third spherical surface22cof the solid immersion lens2is in contact with the plurality of spheres6.

An inner surface (at least the bottom surface35a) of each accommodating portion35may be subjected to a hardening treatment. The inner surface of each accommodating portion35is a region of the surface of the holder3with which at least the sphere6is in contact. The hardening treatment is a treatment in which the hardness of the surface of the holder3(in the present embodiment, the inner surface of each accommodating portion35) is made higher than the hardness of the inside of the holder3(in the present embodiment, the inside of each protrusion34). For example, when each protrusion34is made of aluminum or an aluminum alloy, an alumite treatment can be used as the hardening treatment. For the hardening treatment, it is preferable to select a treatment in accordance with a material forming each protrusion34.

[Example of Image Acquisition Method in Semiconductor Inspection Device]

As illustrated inFIG.1, in the semiconductor inspection device100, an observation part in the semiconductor device S is specified by the objective lens150to which the solid immersion lens unit1is not attached. This observation part is specified by an instruction to the peripheral controller123by the instruction unit132and control of drive of the moving mechanism114by the peripheral controller123.

Subsequently, switching to the objective lens150to which the solid immersion lens unit1is attached is performed, and the correction ring152of the objective lens150is adjusted. The correction ring152is adjusted by an instruction to the peripheral controller123by the instruction unit132and control of drive of the correction ring adjustment motor153by the peripheral controller123. Specifically, the correction ring152is adjusted in accordance with a characteristic of the solid immersion lens2(thickness and refractive index of each part of the solid immersion lens2, etc.), a substrate thickness of the semiconductor device S, a substrate material of the semiconductor device S, etc.

Subsequently, the contact surface21a(seeFIG.3) of the solid immersion lens2is brought into close contact with the surface Sa of the semiconductor device S. The contact surface21aof the solid immersion lens2is brought into close contact by an instruction to the peripheral controller123by the instruction unit132and control of drive of the moving mechanism114by the peripheral controller123.

Subsequently, focusing of the objective lens150to which the solid immersion lens unit1is attached is performed. The focusing of the objective lens150is performed by an instruction to the peripheral controller123by the instruction unit132and control of drive of the moving mechanism114by the peripheral controller123.

Subsequently, the observation part in the semiconductor device S is observed. This observation part is observed by an instruction to each of the camera controller121and the LSM controller122by the instruction unit132, and control of an operation of each of the two-dimensional camera113and the LSM unit115.

As illustrated inFIGS.6and7, when the contact surface21aof the solid immersion lens2is brought into close contact with the surface Sa of the semiconductor device S, the solid immersion lens2moves upward, and the third spherical surface22cof the solid immersion lens2comes into contact with the sphere6rotatably held by the magnetic force of the magnet5. At this time, as illustrated inFIG.6, when the surface Sa of the semiconductor device S is not tilted with respect to the optical axis L (that is, orthogonal to the optical axis L), the solid immersion lens2hardly swings, and the contact surface21aof the solid immersion lens2comes into close contact with the surface Sa of the semiconductor device S. On the other hand, as illustrated inFIG.7, when the surface Sa of the semiconductor device S is tilted with respect to the optical axis L, the solid immersion lens2attempts to swing to follow the surface Sa of the semiconductor device S, and each sphere6rotates while the third spherical surface22cof the solid immersion lens2and the surface of each sphere6are in point contact with each other. As a result, the solid immersion lens2swings smoothly to follow the surface Sa of the semiconductor device S. In this way, the contact surface21aof the solid immersion lens2can be brought into close contact with the surface of the semiconductor device S. Note that factors that cause the surface Sa of the semiconductor device S to be tilted with respect to the optical axis L include poor polishing of the surface Sa, tilting of a mounting board on which the semiconductor device S is mounted, etc.

[Action and Effect]

In the solid immersion lens unit1described above, the solid immersion lens2includes the first lens portion21formed of the first material and the second lens portion22formed of the second material having the refractive index smaller than the refractive index of the first material and coupled to the first lens portion21. In this way, a material having a wider bandgap than that of the first material can be selected as the second material. Therefore, for example, when compared to the case where the entire solid immersion lens2is formed of the first material, even when light having a short wavelength is used, it is possible to easily ensure the amount of light transmitted through the solid immersion lens2. That is, while the first material has a restriction that a material having a high refractive index needs to be selected, the second material does not have such a restriction, so that a degree of freedom of selection is high. Therefore, as the second material, it is possible to select a material having a higher transmittance for light having a shorter wavelength than that of the first material. As a result, in the semiconductor inspection device100including the solid immersion lens unit1, the light source of the LSM unit115can output light in a wavelength range absorbed to some extent by the first lens portion21(first material) and not absorbed by the second lens portion22(second material) (that is, transparent to the second lens portion22). In this way, it is possible to increase the resolution, and it is possible to perform various measurements using generation of electric charges associated with light absorption in the semiconductor device S. Further, the second lens portion22has the concave second spherical surface22afacing the convex first spherical surface21cof the first lens portion21, and the convex third spherical surface22cdisposed to face the objective lens150, and the contact portion40(sphere6) of the holder3comes into contact with the third spherical surface22c. In this way, the contact portion40comes into contact with the solid immersion lens2on the third spherical surface22cwider than the first spherical surface21c, so that the field of view of the solid immersion lens2can be ensured. Further, since the refractive index of the second lens portion22is larger than the refractive index of air, the field of view of the solid immersion lens2can be enlarged as compared with, for example, the case where the solid immersion lens2only has the first lens portion21. Therefore, according to the solid immersion lens unit1, it is possible to ensure the field of view of the solid immersion lens2while enabling observation using light having a short wavelength.

The centers of curvature of the first spherical surface21c, the second spherical surface22a, and the third spherical surface22ccoincide with each other. In this way, it is possible to favorably observe the semiconductor device S.

The contact surface21ais a flat surface. In this way, the contact surface21acan be easily brought into close contact with the surface Sa of the semiconductor device S.

The contact surface21aprotrudes to the opposite side from the objective lens150with respect to the second lens portion22in the direction parallel to the optical axis L of the objective lens150. In this way, it is possible to avoid a decrease in observation accuracy due to the contact of the second lens portion22with the semiconductor device S. That is, stress concentration may occur at a boundary portion between the first lens portion21and the second lens portion22, and it is difficult to improve processing accuracy of the boundary portion. Therefore, unlike the solid immersion lens unit1, when adopting a configuration in which not only the contact surface21aof the first lens portion21but also the second lens portion22comes into contact with the semiconductor device S, for example, since the boundary portion slightly protrudes, the contact surface21amay not be favorably in contact with the surface Sa of the semiconductor device S, and the observation accuracy may decrease. In contrast, in the solid immersion lens unit1, such a situation can be avoided, and a decrease in observation accuracy can be avoided.

The first material contained in the first lens portion21is Si, GaAs, GaP, Ge, diamond, SiC or GaN. In this way, the semiconductor device S can be observed with high resolution.

The second material contained in the second lens portion22is glass, polymer, sapphire, quartz, calcium fluoride, or magnesium fluoride. As described above, as the second material, it is possible to select a material having a lower refractive index than that of the first material.

The contact portion40includes the sphere6rotatably held at a position facing the third spherical surface22c. A part of light incident on the solid immersion lens2is blocked by the sphere6and a structure holding the sphere6(for example, the protrusion34). However, in the solid immersion lens unit1, as described above, since the sphere6comes into contact with the solid immersion lens2on the third spherical surface22cwider than the first spherical surface21cand the second spherical surface22a, the field of view of the solid immersion lens2can be ensured.

[Modifications]

In a first modification illustrated inFIG.8, the contact portion40in contact with the third spherical surface22cof the solid immersion lens2has a plurality of protrusions34. Each of the protrusions34extends from an inner surface of the opening32atoward a center of the opening32a. As illustrated inFIG.9, each protrusion34is configured as follows when viewed from the direction parallel to the optical axis L. Each protrusion34has a fan shape in which a length in a radial direction is longer than a length in a circumferential direction, and a center line34bthereof extends to pass on the optical axis L. A tip surface34cof each protrusion34has a curved surface and is located on a circumference R centered on the optical axis L. A contact position between each protrusion34and the third spherical surface22cis located on the circumference R.

As illustrated inFIG.10(a), in the state before the solid immersion lens2comes into contact with the semiconductor device S, the holder3holds the solid immersion lens2swingably in a direction of an arrow Y. The solid immersion lens2is supported by the support member33. When the contact surface21ais brought into contact with the surface Sa of the semiconductor device S from this state, as illustrated inFIG.10(b), the solid immersion lens2is separated from the support member33, and the third spherical surface22ccomes into contact with three protrusions34. At this time, the solid immersion lens2swings or rotates, so that the contact surface21afollows and comes into close contact with the surface Sa of the semiconductor device S. In this way, favorable close contact between the solid immersion lens2and the semiconductor device S can be obtained. As a result, for example, even when the surface Sa of the semiconductor device S is tilted with respect to the optical axis L, the semiconductor device S can be favorably observed.

In the first modification, the field of view of the solid immersion lens2can be ensured while enabling observation using light having a short wavelength, as in the above embodiment. Further, in the first modification, the contact portion40has the protrusion34extending from the inner surface of the opening32atoward the center of the opening32a. A part of light incident on the solid immersion lens2is blocked by the protrusion34. However, as described above, since the protrusion34comes into contact with the solid immersion lens2on the third spherical surface22cwider than the first spherical surface21c, the field of view of the solid immersion lens2can be ensured.

In the second modification illustrated inFIG.11, the second lens portion22does not include the peripheral surface22d, and includes a flat surface22e. The flat surface22eextends parallel to the contact surface21aand is connected to the first tapered surface21bof the first lens portion21and the second tapered surface22b. Since the flat surface22eis provided, the second tapered surface22bis not flush with and connected to the first tapered surface21b. The apex of the virtual cone including the second tapered surface22bis located below the centers of curvature of the first spherical surface21c, the second spherical surface22a, and the third spherical surface22c. In the second modification as well, the contact surface21aof the first lens portion21protrudes downward with respect to the second lens portion22(to the opposite side from the objective lens150) in the direction parallel to the optical axis L of the objective lens150. In the second modification, the field of view of the solid immersion lens2can be ensured while enabling observation using light having a short wavelength, as in the above embodiment.

The present disclosure is not limited to the above-described embodiment and modifications. The material and shape of each component are not limited to the above-mentioned material and shape, and various materials and shapes can be adopted. The shape of the solid immersion lens2is not limited to the hemispherical shape, and may be, for example, a Weierstrass shape. The contact surface21adoes not necessarily have to be a flat surface. The semiconductor device S may be formed by other indirect transition semiconductors such as diamond and germanium. When the substrate material is diamond, for example, light in an ultraviolet region is output from the light source of the LSM unit115. When the substrate material is germanium, for example, infrared light in a wavelength range of about 1.8 μm is output from the light source of the LSM unit115.

The centers of curvature of the first spherical surface21c, the second spherical surface22a, and the third spherical surface22cdo not have to coincide with each other. For example, when the first material contained in the first lens portion21is different from the substrate material of the semiconductor device S, the centers of curvature of the first spherical surface21c, the second spherical surface22a, and the third spherical surface22cmay be shifted from each other so that an aberration between the first lens portion21and the semiconductor device S is corrected.

The semiconductor inspection device100is not limited to an epi-illumination type device that brings the contact surface21aof the solid immersion lens2into contact with the surface Sa of the semiconductor device S from the upper side, and may be an inverted device that brings the contact surface21ainto contact with the surface Sa from the lower side. In the inverted semiconductor inspection device100, the third spherical surface22cof the solid immersion lens2is in contact with the sphere6even when the contact surface21ais not brought into contact with the surface Sa from the lower side. In this case, the contact surface21aof the solid immersion lens2can be easily brought into close contact with the surface of the semiconductor device S.

REFERENCE SIGNS LIST

1: solid immersion lens unit,2: solid immersion lens,3: holder,6: sphere (contact portion),21: first lens portion,21a: contact surface,21c: first spherical surface,22: second lens portion,22a: second spherical surface,22c: third spherical surface,32a: opening,34: protrusion (contact portion),40: contact portion,100: semiconductor inspection device,111: stage,112: optical system,113: two-dimensional camera (photodetector),115a: photodetector,150: objective lens, L: optical axis, S: semiconductor device (observation object).