JP4606443B2 - Circuit pattern substrate inspection method and substrate inspection apparatus using charged particle beam - Google Patents

Description

  The present invention relates to a substrate inspection technique using a charged particle beam, and in particular, detects foreign matters and defects on a substrate such as a semiconductor wafer having a fine circuit pattern in the inspection technique using a charged particle beam such as an electron beam. Related to inspection technology.

  Along with the higher integration of semiconductor circuits, wiring patterns are becoming increasingly multilayered and complicated, and at the same time, the dielectric constant of insulating film materials between wirings has been reduced and diversified. There is a need for a technique for inspecting such an electrical defect of a semiconductor circuit at high speed and stably during the semiconductor manufacturing process. In system LSIs and the like, it is necessary to develop a wide variety of circuit formation processes in a short period of time, and thus a technique for inspecting various types of circuits is required.

  In response to the needs of such semiconductor circuit manufacturing technology, as described above, a charged particle beam is used to irradiate a wafer in the middle of the semiconductor manufacturing process, and the semiconductor circuit is inspected using the secondary electron contrast generated by the surface potential difference. By doing so, it is possible to inspect the circuit pattern for electrical defects during the semiconductor manufacturing process.

  For example, a method disclosed in, for example, Japanese Patent Application Laid-Open No. 11-121561 (Patent Document 1) is known as a method for inspecting non-conduction of a contact hole including a transistor such as a CMOS. In this method, the contact on the n diffusion layer is inspected by negatively charging the surface, and the contact on the p diffusion layer can be inspected for non-conducting defects by positively charging the surface. It is disclosed. When inspecting on the n diffusion layer, normal contacts are not charged, but non-conductive contacts are negatively charged on the surface, thereby detecting defects as a difference in the contrast of the secondary electron image, In the case of contact inspection on the p-diffusion layer, normal contacts are not charged, but non-conducting contacts are detected as differences in the contrast of secondary electron images by positively charging the surface. Is disclosed.

On the other hand, in Japanese Patent Laid-Open No. 11-87451 (Patent Document 2), a carrier is generated by a laser beam at a pn junction while supplying a charge by charged beam irradiation, and a current induced thereby is taken out from the substrate and measured. A method for inspecting contact defects is disclosed. This method enables non-contact current supply at any location, provides an inspection method for a semiconductor device inspection device that does not require the formation of electrode pads, and inspects and analyzes semiconductor devices by OBIC during the manufacturing process. Is possible.
Japanese Patent Laid-Open No. 11-121561 Japanese Patent Laid-Open No. 11-87451 JP 2000-357483

  However, the conventional electron beam semiconductor inspection method has the following problems.

  In order to inspect non-conduction of a circuit pattern including contacts having various types of junctions such as CMOS, it was necessary to inspect the wafer surface twice in order of positive polarity and negative polarity. For example, the contact 38 on the n diffusion layer 40 as shown in FIG. 2 is inspected by negatively charging the surface. In this case, normal holes are not charged, but contacts that are non-conductive defects are negatively charged.

  Further, the contact 39 on the p diffusion layer 41 is inspected by positively charging the surface. In this case, normal holes are not charged, but contacts that are non-conducting defects are positively charged. As described above, it is necessary to inspect the positive polarity and the negative polarity in order, and it takes time, and there is a problem that uneven charging is likely to occur and sensitivity is lowered.

  Further, in the contact charged during electron beam irradiation, for example, in the contact 38 on the n diffusion layer when charged positively, when the resistance of the junction formed on the substrate varies, the junction Since the charging voltage of the contact varies due to the variation in resistance, there is a problem in that the contrast of the secondary electron image is different and a normal contact is erroneously detected as a defect.

  In addition, in the conventional method of measuring the substrate current when the charged beam is irradiated while irradiating the laser beam, electron-hole pairs are generated in the substrate by the laser beam irradiation, so noise is generated in the substrate current and is weak. There was a problem that it was difficult to detect the difference in OBIC current.

  Furthermore, in the method of generating a carrier by laser beam irradiation and detecting the substrate current, the spatial resolution is limited to the spatial resolution of the laser beam, which makes it difficult to inspect a fine pattern.

  In addition, in semiconductor devices, several doped layers are also formed under the pn junction formed in the contact portion. Therefore, the OBIC current is affected by the junction formed between the respective layers, and the sensitivity is increased. There was a problem of a decrease.

  Furthermore, when an insulating film is formed between the pattern circuit and the Si substrate, as in the case of an SOI wafer, and the pattern circuit and the Si substrate are electrically insulated, the inspection is impossible. There was a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate inspection method that solves the above-mentioned problems, and controls the surface of a wafer having various circuit patterns and the charging of the circuit pattern at high speed and stably, and performs defect inspection at high speed and high accuracy. It is in.

  Another object of the present invention is to provide a technique that contributes to optimization of a semiconductor manufacturing process from the obtained defect information.

  Furthermore, another object of the present invention is to provide a technique that contributes to improving the reliability of a semiconductor device by detecting a process abnormality at an early stage and managing it in the management of a semiconductor manufacturing process.

  First, a method for inspecting non-conduction of a circuit pattern including contacts having various types of junctions such as CMOS will be described. Conventionally, it is necessary to inspect the positive polarity and the negative polarity in order and inspect, which not only takes time, but also has a problem that uneven charging tends to occur and sensitivity is lowered.

  Therefore, in order to avoid inspecting twice by changing the polarity of the surface charge, by irradiating light from the upper surface of the wafer during electron beam irradiation and acquiring a secondary electron image, Means were provided to reduce the effect of contrast on the bond.

The wavelength of light used was a wavelength that transmitted through the insulating film of the circuit pattern and did not transmit Si at the junction. For example, when SiO ₂ and Si ₃ N ₄ are used as the insulating film formed on the circuit pattern, means for irradiating light with a wavelength of 200 nm or more is provided. The light of this wavelength passes through the SiO ₂ and Si ₃ N ₄ formed on the pattern and is absorbed by the Si substrate to generate electron-hole pairs. Since this light cannot pass through the plug formed on the upper surface of the joint, in order to irradiate the joint with light, the light is irradiated from the direction shifted from the direction of the arrangement of the pattern circuits as shown in FIG. Means for irradiating were provided.

  As another means to avoid inspecting twice by changing the polarity of the surface charge, secondary electrons are obtained by irradiating light from the back of the wafer during electron beam irradiation and acquiring secondary electron images. Means were provided for reducing the effect of image contrast on bonding. As a wavelength of light, means for irradiating a wavelength of 900 nm or more and 1200 nm or less that is transmitted through the Si substrate and generates an electron / hole pair at a junction formed on the surface of the Si substrate is provided.

  Thus, by irradiating the ultraviolet light or laser light during electron beam irradiation, electron-hole pairs are generated at the junction. As a result, the difference in charging voltage on the plug surface depending on the type of bonding can be eliminated, and non-conductivity can be inspected on all types of bonding if the inspection is performed once.

  Further, in the present invention, since secondary electrons generated from the surface of the semiconductor circuit are detected to inspect defects, unlike the conventional method of detecting the substrate current, carriers generated on the substrate by laser light irradiation are considered to be noise. The inspection can be performed without becoming. Furthermore, since the spatial resolution of the present invention depends on the spatial resolution of secondary electrons, it is possible to inspect a fine pattern as compared with the conventional method of detecting a substrate current.

In addition, in a conventional inspection method using secondary electron images, in a hole pattern formed on an insulating film such as Si ₃ N ₄ , even if the pattern is irradiated with a charged particle beam, the hole pattern between the hole and the insulating film around the hole Because no potential contrast was formed, no non-aperture inspection could be performed. Therefore, means for acquiring a secondary electron image is provided while conducting at least one type of insulating film surface among different types of insulating films forming the circuit pattern of the region to be inspected. As an example, means for making the surface of the insulating film conductive by irradiating the wafer surface with ultraviolet light during electron beam irradiation was provided.

For example, when inspecting a hole pattern in which the material at the bottom of the hole is Si ₃ N ₄ and the material around the hole is SiO ₂ , the wavelength for transmitting SiO ₂ and making the Si ₃ N ₄ surface conductive is 150 nm or more. A means for irradiating ultraviolet light of 200 nm or less was provided. At this time, a means for introducing ultraviolet light through a fiber or the like was provided, and a means capable of irradiating the wafer surface from a high angle with a pattern having a high aspect ratio.
Furthermore, a filter was provided between the ultraviolet light source and the sample stage as means for removing a part of the secondary charged particles generated by the ultraviolet light irradiation.

  In addition, in the conventional defect inspection method using secondary electron images, it is impossible to distinguish and detect the type of non-conducting defect, for example, non-opening due to the contact hole bottom residue or non-conducting due to wiring voids. . Therefore, a means for acquiring a secondary electron image while irradiating light from the front surface or the back surface during electron beam irradiation was provided.

  Furthermore, a mechanism was provided for comparing the secondary electron image acquired while irradiating light with the secondary electron image acquired without laser irradiation to determine the type of defect. When irradiating light from the back side, a mechanism for irradiating light with a wavelength of 1.2 μm or more was provided.

  When the defect is irradiated with laser, the resistance value of the defect changes due to the heat transfer effect. For this reason, a difference occurs in the charging voltage on the surface of the defect portion depending on the type of defect, and the contrast of the secondary electron image changes. By comparing secondary electron images with and without light irradiation, it is possible to evaluate the type of defect.

  According to the present invention, various types of semiconductor circuit inspection can be performed regardless of the type and material of the circuit pattern of the semiconductor device, and high-sensitivity inspection can be performed.

  In addition, it is possible to detect the types of detected defects separately.

  Furthermore, abnormal charging of the circuit pattern can be prevented, the electron beam irradiation area can be uniformly charged, a stable secondary electron image can be detected at high speed, and high-sensitivity inspection can be performed.

  As a result, early start-up of semiconductor manufacturing processes and early countermeasures against defects have become possible, making it possible to improve the reliability and productivity of semiconductor devices.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
In this embodiment, an example of a non-conducting inspection method in the case where different types of bonds are formed on the substrate of the wafer to be inspected will be described. An example of the configuration of the semiconductor inspection apparatus in the present embodiment is shown in FIG.

  A semiconductor device inspection apparatus 1 includes an electron optical system 2, a stage mechanism system 3, a wafer transfer system 4, a vacuum exhaust system 5, an optical microscope 6, a control system 7, an operation unit 8, and a light irradiation system 9. The electron optical system 2 includes an electron gun 10, a condenser lens 11, an objective lens 12, a detector 13, an energy filter 14, a deflector 15 (for example, an EXB deflector), an electrode 16 on the upper surface of the wafer, and a wafer height detector. Has been.

  The light irradiation system 9 includes an ultraviolet light source 17 and a nozzle 18. The stage mechanism 3 includes an XY stage 19, a holder (sample stage) 20 for holding and placing the wafer, a holder 21 and a retarding power source 23 for applying a negative voltage to the wafer 22. A position detector based on laser length measurement is attached to the XY stage 20. The wafer transfer system 4 is configured such that the wafer 22 moves back and forth among the cassette mounting unit 24, the wafer loader 25, and the XY stage 20.

  The control system 7 includes a signal detection system control unit 26, a blanking control unit 27, a beam deflection correction control unit 28, an electron optical system control unit 29, a stage control unit 30, an electrode control unit 31, and an ultraviolet light control unit 32. ing.

  The operation unit 8 includes an operation screen and operation unit 33, an image processing unit 34, an image / inspection data storage unit (storage unit) 35, and an external server 36.

In this embodiment, a wafer to be inspected having several types of bonding is irradiated with an electron beam while irradiating light 37, and a defect inspection is performed from the detected secondary electron image. As a light source 17 for reducing the influence of the type of bonding, light having a wavelength of 1000 nm or less that is longer than the absorption edge of the insulating film forming the circuit pattern and absorbed by the Si substrate is irradiated. For example, when the insulating film is SiO ₂ , light with a wavelength of 150 nm to 1000 nm is irradiated. When Si ₃ N ₄ is contained in the insulating film, light with a wavelength of 200 nm to 1000 nm is irradiated.

  As the light, for example, a laser beam having a wavelength of 633 nm or an excimer lamp such as D2 can be used. In the case of an excimer lamp using D2, ultraviolet light having a specific wavelength can be obtained by installing a filter for selecting a wavelength after the light source.

  Also, several types of wavelengths can be selected with one light source. For example, a case where a circuit pattern having a cross-sectional structure shown in FIG. 6 is irradiated with laser light having a wavelength of 633 nm will be described. The light 37 generated from the light source 17 is introduced into the vacuum through a vacuum window made of a material through which the generated light 37 can be transmitted. For example, a substance such as quartz, MgF2, or LiF can be used. The light introduced into the vacuum is introduced through an insulating nozzle 18 or the like.

  Thereby, it is possible to acquire a secondary electron image while preventing noise generated due to irregular reflection of light in the vacuum chamber. It is also possible to install a mirror or the like in the nozzle 18 that guides the light, and collect or deflect the light to irradiate the wafer surface. The light can uniformly irradiate an area sufficiently wider than the area where the electron beam is scanned.

When acquiring simultaneously secondary electron image and the light irradiation, it is possible to detect the secondary electrons having a specific energy using the energy filter 14. Thereby, it is possible to inspect by removing noise caused by secondary electrons including photoelectrons emitted by light irradiation. As an example, an energy filter that acquires secondary electrons equal to or higher than a certain threshold can be used. By setting the threshold value to a threshold value that is equal to or lower than the energy of the light 37 and acquiring a secondary electron image, noise due to light irradiation can be reduced.

  The defect detection method will be described according to the inspection flow. FIG. 5 shows an inspection flow. First, the cassette shelf number of the wafer to be inspected is designated on the operation screen 33 (step 53). Then, wafer information such as a pattern layout is input as information on the wafer to be inspected. As inspection conditions, an inspection region, electron beam irradiation energy, beam current, scanning speed, and scanning size when acquiring a secondary electron image are input (step 54). Further, the inspection conditions stored in a database can be used from the information of the wafer to be inspected. Information on the wafer to be inspected, electron beam irradiation conditions, and inspection conditions can be input from the external server 36. As light irradiation conditions, conditions such as wavelength, power, and irradiation region are input.

  When the inspection is started, the wafer 22 is transferred to the inspection apparatus. After the wafer 22 is transferred from the cassette into the wafer loader, the wafer loader is evacuated. Thereafter, the sample is introduced into an inspection chamber that has already been evacuated (step 55).

  After the wafer load is completed, the electron beam irradiation conditions are set to each part by the electron optical system control unit 25 based on the inputted inspection conditions. Then, the stage 19 moves so that the beam calibration pattern is placed under the electron optical system 2 on the wafer holder 21 (step 56). Thereafter, an electron beam image is obtained, and the contrast, etc. of the image are adjusted by adjusting the focus, astigmatism, and detection system settings (step 57). At the same time, the height of the wafer 22 is obtained, and at the time of subsequent electron beam image acquisition, the focusing condition can be automatically adjusted based on the result of the wafer height detection without performing focusing every time.

  Thereafter, alignment of the image of the wafer 22 to be inspected with the optical microscope and the secondary electron image is performed from two points on the wafer 22. Further, a secondary electron beam image is acquired and the brightness is adjusted (step 60). Based on the inspection condition file, when acquiring an electron beam image, the electron beam current, the electron beam irradiation energy, the voltage applied to the energy filter 14, the detector 13 to be used, and the gain of the detection system are set. Set parameters and acquire an electron beam image. When the brightness adjustment is completed, an inspection is executed (step 61). The inspection area is designated in advance in the inspection condition file.

  As an example of a method for inspecting a non-conducting defect by irradiating light 37 using the present embodiment, an embodiment in which the inspection is performed with the circuit pattern of FIG. The wafer surface is irradiated with, for example, an electron beam with an irradiation energy of 500 eV to charge the plug made of Si to a positive polarity. When the n diffusion layer 69 is formed on the p-well 72 formed on the Si substrate 73, a reverse bias is applied to the junction, so that a depletion layer is formed at the junction. As a result, electrons are not supplied from the Si substrate 73 and the plug is charged positively.

  On the other hand, when the p diffusion layer 70 formed on the n-well 71 is formed, a forward bias is applied to the junction, so that electrons are supplied from the Si substrate 73 and the surface of the plug 76 becomes 0V. Accordingly, the secondary electron image at this time is as shown in FIG. Since the non-conductive plug 75 is positively charged and observed dark, it is difficult to distinguish between the normal hole 74 and the non-conductive defect 75 only by inspection using positive polarity charging.

  On the other hand, when laser light having a wavelength of 633 nm is irradiated, the laser light passes through the insulating film 78 and reaches the substrate Si73. This laser beam can generate electron-hole pairs in the depletion layer formed in Si and the junction and excite the electrons in the valence band to the conduction band, so even when reverse bias is applied A current can be passed through.

  Accordingly, the plug 74 is also supplied with electrons from the Si substrate, so that charging of the plug is alleviated. As a result, when laser light is irradiated, a secondary electron image can be acquired without the influence of bonding as shown in FIG. 8, and a non-conducting defect can be detected by one inspection.

  In contrast, when the inspection is performed with the wafer surface charged to a negative polarity, the conventional method applies a reverse bias to the junction between the normal plug 76 and the defective plug 77, so the normal plug 76 and the defective plug 77 are distinguished. Can not do it.

  In this embodiment, since the laser beam is applied to the joint and a current flows through the joint, the defective plug 77 and the defective plug 75 are charged. As a result, even when negative charging is used, defect inspection can be performed from the difference in secondary electron images regardless of the type of bonding.

  At this time, the incident direction in which the ultraviolet light 37 is irradiated will be described next. In a circuit pattern such as a normal memory, as shown in FIG. 9, the patterns are arranged so as to be orthogonal. Normally, poly Si or metal is used as the plug material, so the above ultraviolet light cannot pass through the plug portion. Therefore, a configuration is adopted in which the incident direction of the ultraviolet light 37 can be shifted from the pattern arrangement direction 81 for irradiation. As a result, even in a dense pattern circuit, the junction of the underlying Si is irradiated with ultraviolet light to reduce the influence of bonding, and non-defects can be detected.

Next, an example of a method for detecting a non-opening defect in a hole whose base is formed on an insulating film such as Si ₃ N ₄ will be described. As a light source to be irradiated to conduct on the underlying insulating film, light having a wavelength longer than the absorption edge of the insulating film forming the circuit pattern and shorter than the absorption edge of the underlying insulating film is irradiated. For example, as shown in FIG. 10, when the upper insulating film 45 is SiO ₂ and the underlying insulating film 43 is Si ₃ N ₄ , ultraviolet light having a wavelength of 140 nm to 200 nm is irradiated.

  As the light source 17, an ultraviolet light source such as ArF (wavelength: 193 nm), Kr2 (wavelength: 146 nm), Xe (wavelength: 172 nm) can be used. For example, the case where a circuit pattern having a cross-sectional structure shown in FIG. 10 is irradiated with ultraviolet light having a wavelength of 193 nm will be described.

When the circuit pattern of FIG. 10 is irradiated with an electron beam without ultraviolet light irradiation and the pattern surface is charged positively, both SiO ₂ and the underlying Si ₃ N ₄ are charged positively. The non-opening hole 83 becomes a secondary electron image as shown in FIG. 11A, and it is impossible to detect a defect.

On the other hand, when ultraviolet light having a wavelength of 193 nm is irradiated, the ultraviolet light passes through the SiO ₂ of the upper layer 45 and reaches the Si ₃ N ₄ of the base 43. Since this ultraviolet light is Si ₃ N ₄ and can excite electrons in the valence band to the conduction band, secondary electrons are likely to be emitted from the bottom of the normal hole 82.

As a result, as shown in FIG. 11B, the normal hole 82 was bright and the non-opening hole 83 was observed dark, and non-opening inspection was possible even on an insulating film such as Si ₃ N ₄ .

  At this time, the incident direction in which light is irradiated will be described next. As shown in FIG. 10, there may be a layer 84 made of the same material as the base insulating film between the layers. In a wafer having such a structure, a method of irradiating at a high angle is effective for allowing light to reach the underlying insulating film.

  FIG. 12 shows an outline of the vicinity of the wafer surface of an apparatus for irradiating light from a high angle. In this configuration, light 37 is guided to the probe tip using a fiber 85 or the like and can be irradiated from the side of the objective lens 12. As a result, it becomes possible to irradiate light 37 at a high angle with respect to the wafer surface, it is possible to efficiently conduct the insulating film on the bottom of the hole, and non-opening inspection of holes on the insulating film is possible. It was.

  The location determined as a defect using the method described above is automatically recorded with the coordinates of the defect location, the signal value, the type of defect, the size of the defect, etc., and the equivalent on the wafer map in the operation screen 33. Marks with defects are displayed by type at the locations to be operated. When the inspection of the area specified in the inspection condition file is completed, the defect portion can be imaged again (step 62 in FIG. 5).

  According to the method described above, various types of semiconductor circuits can be inspected regardless of the type and material of circuit pattern bonding, and high-sensitivity inspection can be performed. As a result, it has become possible to contribute to early start-up of semiconductor manufacturing processes and early countermeasures against defects.

(Example 2)
In this embodiment, an example of a method for inspecting non-conduction by irradiating laser light 37 from the back surface of the wafer 22 will be described. An example of the semiconductor inspection apparatus used in this embodiment is shown in FIG. The electron optical system 2, the stage mechanism system 3, the wafer transfer system 4, the vacuum exhaust system 5, the optical microscope 6, the control system 7, the operation unit 8, and the laser light irradiation system 9 are configured. Except for the laser beam irradiation system 9, the configuration is the same as that described in the first embodiment. The laser light 37 generated from the laser light source 17 is introduced into the vacuum through a vacuum window made of a material that can transmit the generated laser light. The laser beam introduced into the vacuum is irradiated from the back surface of the wafer 22 to be inspected.

  Windows for performing laser light irradiation are provided on the back surface of the sample stage 20, the holder 21 and the XY stage 19 of the wafer 22 to be inspected. This window is made of a material that can transmit laser light 37. On the other hand, the electron beam 51 for acquiring the inspection image is irradiated and scanned from the upper surface of the wafer. The laser beam 37 and the electron beam 51 can simultaneously irradiate the same part from the back surface and the front surface of the wafer 22, and a secondary electron image on the wafer surface can be acquired while the laser beam 37 is irradiated from the back surface. .

  When a secondary electron image is acquired simultaneously with laser light irradiation, secondary electrons excited by the laser light become noise in the secondary electron image. In order to remove this noise, it is also possible to detect secondary electrons having specific energy using the energy filter 14. Thereby, it is possible to remove the noise emitted by the laser light irradiation and inspect it. As an example, it is possible to use an energy filter 14 that acquires secondary electrons equal to or higher than a certain threshold.

  For example, different types of junctions may be formed on the substrate of the wafer to be inspected, such as CMOS. First, an example of a method for performing defect inspection from a detected secondary electron image by irradiating an electron beam from the wafer surface while irradiating a wafer to be inspected having several types of bonding from the back surface of the wafer. .

  Conventionally, as described in the first embodiment, when the circuit pattern shown in FIG. 6 is charged to the positive polarity, the plug made of Si is also charged to the positive polarity. The secondary electron image at this time is as shown in FIG. 7, and it was difficult to distinguish between the normal hole 74 and the non-conductive defect 75 only by the inspection using the positive charge. On the other hand, in this embodiment, as a laser light source 17 for reducing the influence due to the type of bonding, for example, a laser beam having a wavelength of 900 to 1200 nm that can pass through a Si substrate and perform electron excitation at the bonding portion. Irradiate.

  This wavelength of laser light transmits not only the Si substrate but also substances such as oxide films and insulating films. For this reason, when laser light is irradiated from the back surface of the wafer, it is possible to transmit the laser beam to the bonded portion through the Si substrate. This laser light can excite valence band electrons to the conduction band at the junction. Therefore, even when the electron beam is irradiated so that a reverse bias is applied to the junction, the electrons are supplied from the Si substrate and the junction, so that charging of the plug 74 is alleviated. As a result, when laser irradiation is performed, it is possible to acquire a secondary electron image with little influence of bonding as shown in FIG. 8, and non-conducting defects can be detected by one inspection.

  In the present embodiment, since the light 37 is irradiated from the back surface of the wafer, it is possible to inspect regardless of the shape or material of the pattern formed on the Si substrate. Further, since the laser beam of this wavelength can pass through the oxide film, it is effective for inspecting a circuit pattern formed on the oxide film such as an SOI wafer. Basically, it is desirable to install a window for laser beam irradiation on the back surface of the sample stage 20, the wafer holder 21 and the XY stage 19. Alternatively, the bottoms of the sample stage 20, the wafer holder 21, and the stage 19 are made of a material that can transmit laser light 37, such as poly Si, so that the inspection is performed without installing a window.

  Next, an example of a method for distinguishing and detecting the type of non-conducting defect as shown in FIG. 4, for example, non-opening 47 due to the residue at the bottom of the contact hole or non-conducting 48 due to the void of the wiring will be described.

  Conventionally, when the circuit pattern shown in FIG. 4 is positively charged, both the defect 47 due to the non-opening due to the hole bottom residue and the defect 48 due to the void generated in the plug are positively charged. Therefore, it is difficult to distinguish and detect the defective plug 47 and the defective plug 48 from the secondary electron image at this time.

  On the other hand, in this embodiment, in order to detect each defect type, it is possible to acquire a secondary electron image while irradiating the laser beam 37 from the back surface of the wafer. As the laser light source 17, for example, a laser beam having a wavelength of 900 or more that is transmitted through a Si substrate and capable of performing electron excitation in the wiring portion is irradiated. This wavelength of laser light transmits not only the Si substrate but also substances such as oxide films and insulating films.

  For this reason, when the laser beam 37 is irradiated from the back surface of the wafer, it is possible to transmit the laser beam to the defective portion through the Si substrate. This laser beam is absorbed by the junction or the wiring part. At this time, when there is a defect such as a non-opening or a void in the wiring part, a thermoelectromotive force is generated in the defective part by the energy of the laser beam. When the resistance of the defective portion is changed by the thermoelectromotive force, the charging voltage of the defective portion is changed. As a result, the contrast of the secondary electron image of the defective portion is also changed.

  At this time, since the thermoelectromotive force due to laser light irradiation varies depending on the type of defect, the change in contrast of the secondary electron image varies depending on the type of defect. From the contrast change of the secondary electron image when the laser beam 37 is irradiated and when the laser beam 37 is not irradiated, it is possible to detect the types of defects detected as non-defect defects by the conventional method.

  In this embodiment, since the laser beam 37 is irradiated from the back surface of the wafer, it is possible to inspect regardless of the shape or material of the pattern formed on the Si substrate. Further, since the laser beam of this wavelength can pass through the oxide film, it is also effective for inspection of a circuit pattern formed on the oxide film such as an SOI wafer. Basically, it is desirable to install a window for laser beam irradiation on the back surface of the sample stage 20, the wafer holder 21 and the XY stage 19. Alternatively, the bottoms of the sample stage 20, the wafer holder 21, and the stage 19 are made of a material that can transmit the laser light 37, such as poly Si, so that inspection can be performed without installing a window.

  Alternatively, when the circuit pattern is not complicated, it is possible to detect the defect by distinguishing the type of non-conducting defect even by the method of irradiating the light 37 from the wafer surface as shown in the first embodiment. In this case, the light source 17 is irradiated with light having a wavelength longer than the absorption edge of the insulating film and shorter than the absorption edge of the wiring material.

For example, when the insulating film is SiO ₂ and the wiring material is poly Si, light with a wavelength of 150 nm to 1000 nm is irradiated. When Si ₃ N ₄ is contained in the insulating film, light with a wavelength of 200 nm to 1000 nm is irradiated. When light 37 having this wavelength is irradiated onto the wafer surface, the light passes through an insulating film such as SiO ₂ and is absorbed by the wiring portion.

  At this time, if there is a defect such as a non-opening or a void in the wiring portion, a thermoelectromotive force is generated in the defective portion by the energy of the light 37 as in the case where the laser beam is irradiated from the back surface of the wafer 22 described above. When the resistance of the defective portion is changed by the thermoelectromotive force, the charging voltage of the defective portion is changed. As a result, the contrast of the secondary electron image of the defective portion is also changed. At this time, since the thermoelectromotive force due to light irradiation varies depending on the type of defect, the change in contrast of the secondary electron image varies depending on the type of defect.

  From the change in the contrast of the secondary electron image when the light 37 is irradiated and when the light 37 is not irradiated, it has become possible to distinguish and detect the types of defects detected as non-defects in the conventional method.

(Example 3)
In addition, this method stabilizes the charging of the wafer surface and makes it possible to obtain a stable secondary electron image. In this embodiment, an example of a method for stabilizing the charging of the wafer surface will be described.

  In a conventional inspection apparatus, when an insulating material is formed on at least a part of a circuit to be inspected, the wafer surface may be abnormally charged during the inspection depending on the layout of the circuit pattern. As a result of abnormal local charging or uneven charging, the secondary electron image may be shifted or uneven, and as a result, an inspectable secondary electron image may not be acquired. This is because if the surface of the wafer is abnormally charged, the trajectory of the primary electron beam slightly shifts due to surface charging, making it impossible to obtain a secondary electron image of the desired area, or areas where the charging voltage is abnormally different. If they are adjacent to each other, the trajectory of the secondary electrons is affected, and a desired secondary electron image cannot be obtained.

  For example, as shown in FIG. 14, an abnormally high potential difference is generated between a region 51 where the density of the conductor is high and a region 52 where the insulating film is high as an inspection pattern. For this reason, secondary electrons emitted near the boundary between the region 51 with a high wiring density and the region 52 with a high proportion of the insulating film do not reach the detector 13, making it difficult to inspect the edge of the region. there were. Alternatively, in the pattern formed on the insulating film or dielectric film, since the circuit pattern is electrically insulated from the Si substrate, it becomes easy to be charged by electron beam irradiation, and the secondary electron image shifts during electron beam irradiation. As a result, there is a problem that a secondary electron image of a desired region becomes difficult or a pattern shape is deformed and observed.

  As a method for removing the charge on the surface, as disclosed in Japanese Patent Laid-Open No. 2000-357483 (Patent Document 3), UV light is applied in synchronization with a time when a secondary electron image for inspection is not acquired. There is a method of irradiating the surface of an inspection wafer. In this method, the charged particle beam and ultraviolet light for charge removal are alternately irradiated to remove the charge on the wafer, so that the entire charged particle irradiation area can be removed, but in the secondary electron image It has been difficult to remove local unevenness of the secondary electron image caused by charging. Further, unevenness of the secondary electron image due to abnormal charging on the surface or uneven charging can be reduced to some extent by optimizing the irradiation conditions of the electron beam used for the inspection. However, with the increase in variety of semiconductor circuits, there is a problem that it takes time to realize optimization for each type.

  In this embodiment, in order to avoid such abnormal charging, a means for acquiring a secondary electron image while irradiating an electron beam while irradiating light and making the wafer surface uniformly charged is provided. At this time, the light can be uniformly applied to an area sufficiently larger than the electron beam scanning area.

In this embodiment, the semiconductor inspection apparatus shown in FIG. 1 can be used. As a light source 17 for stabilizing the charging of the wafer surface, light having a wavelength shorter than the absorption edge of the insulating film forming the circuit pattern is irradiated. For example, when the insulating film surface is SiO ₂ , ultraviolet light having a wavelength of 150 nm or less is irradiated. When the surface of SiO ₂ is irradiated with, for example, ultraviolet light having a wavelength of 126 nm, electrons in the valence band on the surface of SiO ₂ are excited to rise to the conductor and become conduction electrons. Thereby, only the SiO ₂ surface is conductive. As the ultraviolet light source, for example, an Ar2 (wavelength: 126 nm) or excimer lamp such as D2, a third harmonic of a YAG laser (wavelength: 118 nm), or an Ar2 excimer laser (wavelength: 126 nm) can be used.

  In the case of an excimer lamp using D2, ultraviolet light having a specific wavelength can be obtained by installing a filter for selecting a wavelength after the light source. In addition, since several types of wavelengths can be selected with one light source, the present embodiment can be realized with the same apparatus as the first and second embodiments according to the circuit pattern of the wafer to be inspected.

  Here, as an example, an embodiment in which ultraviolet light (wavelength 126 nm) of an excimer lamp made of Ar 2 is used is shown. The ultraviolet light 37 generated from the light source 17 is introduced into the vacuum through a vacuum window made of a material that can transmit the generated ultraviolet light 37. For example, a substance such as MgF2 or LiF can be used. The ultraviolet light introduced into the vacuum is introduced through an insulating nozzle 18 or the like. As a result, it is possible to acquire a secondary electron image while preventing noise generated due to irregular reflection of ultraviolet light in the vacuum chamber.

  Further, a mirror or the like can be installed in the nozzle 18 for guiding the ultraviolet light, and the ultraviolet light can be condensed or deflected to irradiate the wafer surface. The ultraviolet light can uniformly irradiate an area sufficiently wider than the area where the electron beam is scanned.

  When a secondary electron image is acquired simultaneously with the irradiation with ultraviolet light, secondary electrons having specific energy can be detected using the energy filter 14. A monochromator having the same function as the filter for selecting the wavelength may be used. Thereby, it is possible to inspect by removing noise caused by secondary electrons including photoelectrons emitted by ultraviolet light irradiation. As an example, an energy filter that acquires secondary electrons equal to or higher than a certain threshold can be used. By setting the threshold value to a threshold value that is equal to or lower than the energy of the ultraviolet light 37 and acquiring a secondary electron image, noise due to ultraviolet light irradiation can be reduced.

  An example of the secondary electron image acquired using a present Example is shown. In the conventional inspection method, the secondary electron image may drift due to charging of the wafer surface, or a part of the pattern may not be observed. In general, when electrons are irradiated on the surface of an insulating film, secondary electrons are emitted and charged. Especially for conductive patterns floating in insulating films and patterns formed on SOI wafers, depending on the type of pattern, pattern charging may become abnormal locally, making it difficult to obtain a secondary electron image that can be inspected. there were.

  When an electron beam is irradiated while irradiating such a pattern with ultraviolet light to make the surface of the insulating film conductive, if an abnormal charge is formed on the surface of the insulating film, the electron beam irradiation region and nearby electrons are charged. Therefore, an extreme potential difference is not locally formed in the electron beam scanning region.

  As a result, when this embodiment is used, a stable secondary electron image can be detected, and a highly sensitive inspection can be performed.

Example 4
In addition, this technique allows the wafer surface to be positively or negatively charged before inspection, and then acquire a secondary electron image, thereby increasing the potential contrast and enabling high-speed and high-sensitivity inspection. Become. In this embodiment, an example of a method for performing high-speed and high-sensitivity inspection by charging the wafer surface to positive polarity using light will be described.

  In the conventional inspection method, high-sensitivity inspection is performed by increasing the potential contrast by irradiating an electron beam before the inspection and acquiring a secondary electron image after charging the wafer surface positively or negatively in advance. Could be done. However, in the method of obtaining a potential contrast after irradiating an electron beam to the wafer surface in advance, it takes time to charge the wafer surface by scanning the electron beam 49 before the inspection. Further, it is difficult to uniformly charge the wafer surface.

  In the present embodiment, means for uniformly charging the wafer surface by irradiating light before or during irradiation with the electron beam 50 is provided. Furthermore, an electrode was provided above the wafer, and a means for charging the wafer surface positively by controlling the electric field on the wafer surface by applying a voltage higher than the wafer surface to the electrode was provided. In this embodiment, the semiconductor inspection apparatus shown in FIG. 1 can be used.

  First, in this embodiment, a method for charging the wafer surface to positive polarity will be described. By irradiating the wafer surface with light 37, the wafer surface can be charged. Alternatively, by applying a positive voltage to the wafer 22 on the electrode 16 placed on the upper surface of the wafer 22 simultaneously with the irradiation of the light 37, an electric field is generated on the upper surface of the wafer to control the charging voltage on the wafer surface. it can.

As the wavelength of light, light having a wavelength shorter than the absorption edge of the insulating film forming the circuit pattern is irradiated. For example, when the insulating film is SiO ₂ , ultraviolet light having a wavelength of 150 nm or less is irradiated. As the ultraviolet light source, for example, an Ar2 (wavelength: 126 nm) or excimer lamp such as D2, a third harmonic of a YAG laser (wavelength: 118 nm), or an Ar2 excimer laser (wavelength: 126 nm) is used as in the first embodiment. be able to.

When the insulating film is Si ₃ N ₄ , UV light with a wavelength of 200 nm or less is irradiated. For example, when the insulating film on the wafer surface is SiO ₂ , a method for charging the wafer surface to positive polarity will be described. When the surface of SiO ₂ is irradiated with, for example, ultraviolet light having a wavelength of 126 nm, electrons in the valence band on the surface of SiO ₂ are excited to a vacuum level by the photoelectric effect. For this reason, as a result of electrons generated by the photoelectric effect being released from the SiO ₂ surface into a vacuum or diffusing in the insulating film, the ultraviolet light irradiation region is entirely charged to be positive. Simultaneously with UV light irradiation, if a positive voltage is applied to the electrode with respect to the wafer, electrons are extracted from the wafer surface, increasing the efficiency of secondary electron emission from the wafer surface, making the surface of the wafer 22 efficiently positive. Can be charged.

  By adjusting the voltage of the electrode 16, the charging voltage on the wafer surface can be controlled. By applying a uniform potential to the ultraviolet light irradiation region and the electrode 16, a region sufficiently wider than the electron beam scanning region can be uniformly charged. As a result, a uniform secondary electron image can be acquired.

  As an electron beam scanning method for acquiring wafer charging light 37 and an inspection image, the wafer is divided into several inspection regions, and charging of the wafer 22 and secondary electron image acquisition are alternately repeated, During the movement time of the wafer 22, the wafer surface can be efficiently charged to a positive polarity and inspected. FIG. 15 shows an example of the light 37 scanning method. First, the light 37 is irradiated and scanned as shown in FIG. 15A under the condition where the light 37 is set in the first irradiation area 65 and the voltage of the electrode 16 is set.

  Next, the electron beam 51 for image acquisition is scanned in the first scanning region 66 as shown in FIG. 15B to acquire a secondary electron image. At this time, the voltage of the electrode 16 is switched to the set value at the time of image acquisition to acquire a secondary electron image. Next, as shown in FIG. 15C, the electrode voltage is switched to the set value at the time of charging, and the second irradiation region 67 is irradiated with the light 37.

  Thereafter, the electrode voltage is switched again to the set value at the time of acquiring the secondary electron image, and the second scanning region 68 is scanned with the image acquiring electron beam 51. At this time, the light 37 can be irradiated while moving the wafer 22. Thus, since the light 37 can be irradiated during the movement time of the wafer 22, it is possible to inspect without taking extra time for charging the wafer.

  Further, as shown in FIG. 16, the light source 17 for charging the wafer and the electrode 16 for controlling the charging voltage at the time of charging are set so as to be shifted from the optical axis of the electron optical system 2, and charging and secondary electron image detection are performed. Can be performed continuously in the same vacuum chamber. As a method of removing noise entering the secondary electron detector by irradiation of light 37, a voltage is applied to the energy filter 14 arranged in front of the detector 13 to detect secondary electrons separated by energy. it can.

  By the method described above, the wafer surface can be positively charged stably at high speed, and high-speed and high-sensitivity inspection is possible.

  Furthermore, in the conventional method of charging the wafer surface using an electron beam, the potential distribution on the upper surface of the wafer is emitted from the wafer as the electron beam irradiated to charge the wafer, the electron beam irradiated when acquiring the inspection image, and the wafer. Therefore, it is necessary to form a potential distribution that can simultaneously control the trajectories of secondary electrons, and it is difficult to satisfy the conditions applicable to various types of semiconductor circuits.

  However, by providing a means for charging the wafer surface by irradiating light, an electrode that forms a potential distribution that can control only the electron beam irradiated when acquiring the inspection image and the secondary electron trajectory emitted from the wafer. If conditions are used, inspection becomes possible. Therefore, it has become much easier to determine the inspection conditions for each wafer.

  In summary, the first point is that the step of irradiating / scanning the substrate on which the circuit pattern is formed with the primary charged particle beam from the charged particle source, the step of irradiating the circuit pattern substrate with light, and the circuit pattern substrate And a step of inspecting the conduction / non-conduction of the circuit pattern from the change in the contrast of the detected signal.

  The second point is that a primary charged particle beam from the first charged particle source is charged on a substrate on which a circuit pattern has been formed in advance, and a circuit pattern is formed from the primary charged particle beam from the second charged particle source. A step of irradiating and scanning the substrate, a step of irradiating the circuit pattern substrate with light, a step of detecting secondary charged particles from the circuit pattern substrate, and a continuity / non-conduction of the circuit pattern based on a change in the contrast of the detected signal. And a step of inspecting continuity. Specifically, the first charged particle source and the second charged particle source described above may be the same.

  More specifically, the wavelength of the light used in the light irradiation step includes a wavelength of 200 nm to 1200 nm. Still further, the wavelength of light used in the step of irradiating the light includes a wavelength of 900 nm to 1200 nm.

  Further, as the step of irradiating the light, infrared light is irradiated from the back surface of the wafer.

  The third point is the step of irradiating and scanning the substrate on which the circuit pattern is formed with the primary charged particle beam from the charged particle source, the step of irradiating the circuit pattern substrate with light, and the secondary charged particles from the circuit pattern substrate. And a step of selectively conducting the surface of the insulating film according to the type of the insulating film constituting the circuit pattern formed on the substrate, and from the secondary charged particles from the substrate And a step of inspecting the conduction / non-conduction of the circuit pattern from the change of the contrast of the detected signal based on the signal. Specifically, the step of conducting the surface of the insulating film is to use light. Another feature is that a wavelength of 150 nm to 200 nm is used as the light in the step of irradiating the light.

  The fourth point is that a sample stage on which a substrate is placed, a charged particle source, a deflector that scans a primary charged particle beam from the charged particle source on a substrate on which a circuit pattern is formed, and a primary charged particle beam An objective lens for irradiating the substrate, a light source for irradiating the substrate with light, and irradiating the circuit pattern substrate with light from the light source to detect secondary charged particles obtained from the substrate, and based on the detected secondary charged particles And an inspection unit that stores the next charged particle image and inspects the conduction / non-conduction of the circuit pattern from the contrast of the stored image. Moreover, it exists also in the point which has arrange | positioned the said light source under the sample stand. Furthermore, it may be characterized by having a filter provided between the light source and the sample stage.

  The fifth point is that a charged particle source, a step of irradiating and scanning a substrate on which a circuit pattern is formed with a primary charged particle beam from the charged particle source, and a circuit pattern on the substrate electrically from the back surface of the substrate. The step of irradiating the surface of the member forming the circuit pattern with light to stabilize the surface potential, and based on a signal from secondary charged particles from the substrate There is also a method characterized by inspecting the quality of the pattern. Specifically, a wavelength of 150 nm or less is used as the light. Further, the primary electron beam and the light are simultaneously irradiated.

  The sixth point is that the charged particle source, the step of irradiating and scanning the substrate on which the circuit pattern is formed with the primary charged particle beam from the charged particle source, and the surface of the member forming the circuit pattern on the substrate The method includes the step of irradiating light to make the substrate surface potential positive, and checking the quality of the pattern based on a signal from secondary charged particles from the substrate. Specifically, a wavelength of 150 nm or less is used as the light. More specifically, in the step of positively charging the surface potential, there is a mechanism for adjusting the potential of the electrode for adjusting the potential of the substrate surface installed above the substrate.

  As described above, the feature of the present invention is that the electrical connection state is inspected without physically contacting the probe with the circuit pattern provided on the substrate. That is, the electrical characteristics (circuit pattern conduction / non-conduction state) are inspected at the wafer inspection stage before the probe inspection. In particular, light is irradiated to the PN junction, the resistance is lowered, and the current is applied to irradiate light in a positively charged state, and when the brightness is darker than the surroundings, it is determined as a defect, and conversely, it is negatively charged. When it is, it can be determined that a brighter area than the periphery is a defect.

The block diagram which shows an example of the semiconductor inspection apparatus of this invention. Explanatory drawing of the conventional method which test | inspects the non-conduction of a contact hole. Explanatory drawing of the problem of the conventional inspection method. Explanatory drawing of the kind of non-conduction of a contact hole. The figure which shows an example of the test | inspection flow in this invention. Explanatory drawing of the CMOS test | inspection method of this invention. The figure which shows an example of the secondary electron image at the time of using the conventional inspection method. The figure which shows an example of the secondary electron image at the time of using the inspection method of this invention. Explanatory drawing of the incident direction of light. Explanatory drawing of an example of the test | inspection method of this invention. The figure which shows an example of the secondary electron image at the time of using the conventional inspection method and the inspection method of this invention. The block diagram which shows an example of the semiconductor inspection apparatus of this invention. The block diagram which shows an example of the semiconductor inspection apparatus of this invention. The figure which shows an example of the secondary electron image at the time of producing uneven charging. Explanatory drawing which shows an example of the scanning system of the electron beam and light of this invention. The block diagram which shows an example of the semiconductor inspection apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus, 2 ... Electro-optical system, 3 ... Stage, 4 ... Wafer conveyance system, 5 ... Vacuum exhaust system, 6 ... Optical microscope, 7 ... Control system, 8 ... Operation part, 9 ... Light irradiation system, 10 ... Electron gun, 11 ... condenser lens, 12 ... objective lens, 13 ... detector, 14 ... energy filter, 15 ... deflector, 16 ... electrode, 17 ... light source, 18 ... nozzle, 19 ... XY stage, 20 ... wafer holder, 21 ... Holder, 22 ... Wafer, 23 ... Retarding power supply, 24 ... Wafer cassette, 25 ... Wafer loader, 26 ... Signal detection system control unit, 27 ... Blanking control unit, 28 ... Beam deflection correction unit, 29 ... Electro-optic system control 30 ... Stage control unit 31 ... Electrode control unit 32 ... Light control unit 33 ... Operation screen 34 ... Image processing unit 35 ... Data holding unit 36 ... External server 37 ... Light 38 ... n diffusion Contact hole on the layer, 39 ... contact hole on the p diffusion layer, 40 ... n diffusion layer, 41 ... p diffusion layer, 42 ... n well, 43 ... insulating film 44 ... Hole pattern, 45 ... Insulating film around the hole, 46 ... Normal hole, 47 ... Non-opening due to residue, 48 ... Non-conduction due to void, 49 ... Electron beam for preliminary irradiation, 50 ... Electron beam for image acquisition, 51 ... area 52 ... area 53 ... wafer set 54 ... inspection condition input 55 ... load 56 ... stage movement 57 ... beam calibration 58 ... alignment 59 ... calibration 60 ... adjustment 61 ... inspection 62 ... Image acquisition, 63 ... Result output, 64 ... Unload, 65 ... First region, 66 ... First scanning region, 67 ... Second region, 66 ... Second scanning region, 69 ... n diffusion layer, 70 ... p diffusion layer, 71 ... N well, 72 ... P well, 73 ... Si substrate, 74 ... normal plug, 75 ... defective plug, 76 ... normal plug, 77 ... defective plug, 78 ... interlayer insulating film, 79 ... field Oxide layer, 80 ... Gate electrode, 81 ... Pattern arrangement direction, 82 ... Normal hole, 83 ... Non-open hole, 84 ... Spacer, 85 ... F Iba.

Claims (6)

A step of irradiating and scanning a primary charged particle beam from a charged particle source onto a circuit pattern substrate placed on a sample stage, in which a circuit pattern including an insulating film and a wiring material is formed;
By irradiating the circuit pattern substrate with ultraviolet light from an ultraviolet light source, and simultaneously applying a positive voltage to the circuit pattern substrate on the electrode placed on the upper surface of the circuit pattern substrate, the upper surface of the circuit pattern substrate Generating an electric field to positively charge the charging voltage on the surface of the circuit pattern substrate;
Removing a part of the secondary charged particles generated by the ultraviolet light irradiation with a filter provided between the ultraviolet light source and the sample stage;
Detecting secondary charged particles from the circuit pattern substrate;
And a step of inspecting conduction / non-conduction of the circuit pattern from a change in contrast of the detected signal,
A circuit pattern substrate inspection method using a charged particle beam, wherein a wavelength of the ultraviolet light is shorter than an absorption edge of the insulating film. Using a primary charged particle beam from a first charged particle source to form a circuit pattern including an insulating film and a wiring material in advance, and charging a circuit pattern substrate placed on a sample stage;
Irradiating and scanning the circuit pattern substrate on which a circuit pattern is formed with a primary charged particle beam from a second charged particle source;
By irradiating the circuit pattern substrate with ultraviolet light from an ultraviolet light source, and simultaneously applying a positive voltage to the circuit pattern substrate on the electrode placed on the upper surface of the circuit pattern substrate, the upper surface of the circuit pattern substrate Generating an electric field to positively charge the charging voltage on the surface of the circuit pattern substrate;
Removing a part of the secondary charged particles generated by the ultraviolet light irradiation with a filter provided between the ultraviolet light source and the sample stage;
Detecting secondary charged particles from the circuit pattern substrate;
And a step of inspecting conduction / non-conduction of the circuit pattern from a change in contrast of the detected signal,
A circuit pattern substrate inspection method using a charged particle beam, wherein a wavelength of the ultraviolet light is shorter than an absorption edge of the insulating film. A step of irradiating and scanning a circuit pattern substrate formed on a sample stage with a circuit pattern including an insulating film and a wiring material formed from a primary charged particle beam from a charged particle source;
By irradiating the circuit pattern substrate with ultraviolet light from an ultraviolet light source, and simultaneously applying a positive voltage to the circuit pattern substrate on the electrode placed on the upper surface of the circuit pattern substrate, the upper surface of the circuit pattern substrate Generating an electric field to positively charge the charging voltage on the surface of the circuit pattern substrate;
Removing a part of the secondary charged particles generated by the ultraviolet light irradiation with a filter provided between the ultraviolet light source and the sample stage;
Detecting secondary charged particles from the circuit pattern substrate;
A step of selectively conducting the surface of the insulating film according to the type of insulating film constituting the circuit pattern formed on the substrate, and detecting based on a signal from secondary charged particles from the substrate And a step of inspecting conduction / non-conduction of the circuit pattern from a change in contrast of the processed signal,
A circuit pattern substrate inspection method using a charged particle beam, wherein a wavelength of the ultraviolet light is shorter than an absorption edge of the insulating film. In the circuit pattern substrate inspection method using the charged particle beam according to claim 3,
A circuit pattern substrate inspection method using a charged particle beam, characterized by performing ultraviolet light irradiation as a step of conducting the insulating film surface. A sample stage on which a circuit pattern substrate on which a circuit pattern including an insulating film and a wiring material is formed;
A charged particle source;
A deflector that scans the circuit pattern substrate with a primary charged particle beam from the charged particle source;
An objective lens for irradiating the circuit pattern substrate with a primary charged particle beam;
An ultraviolet light source for irradiating the circuit pattern substrate with ultraviolet light having a wavelength shorter than the absorption edge of the insulating film;
Means for removing a part of secondary charged particles generated by the ultraviolet light irradiation by a filter provided between the ultraviolet light source and the sample stage ;
An electrode for charging control that is installed on the upper surface of the circuit pattern substrate and applies a positive voltage to the circuit pattern substrate;
Irradiating the circuit pattern substrate with a primary charged particle beam from the charged particle source, detecting secondary charged particles obtained from the circuit pattern substrate, and storing a secondary charged particle image based on the secondary charged particle image An inspection unit for inspecting the conduction / non-conduction of the circuit pattern from the contrast of the secondary charged particle image;
A circuit pattern substrate inspection apparatus using a charged particle beam. A sample stage on which a circuit pattern substrate on which a circuit pattern including an insulating film and a wiring material is formed;
A charged particle light source system for irradiating the circuit pattern substrate with a primary charged particle beam; and
An ultraviolet light source capable of irradiating the circuit pattern substrate with ultraviolet light;
Means for removing a part of secondary charged particles generated by the ultraviolet light irradiation by a filter provided between the ultraviolet light source and the sample stage ;
An electrode for charging control that is installed on the upper surface of the circuit pattern substrate and applies a positive voltage to the circuit pattern substrate;
Irradiating the primary charged particle beam onto the circuit pattern substrate, detecting secondary charged particles obtained from the circuit pattern substrate, storing a secondary charged particle image based on the secondary charged particle image, and storing the stored secondary charged particle image An inspection section for inspecting the conduction / non-conduction of the circuit pattern from the contrast of
Control means capable of controlling the wavelength of the ultraviolet light to be shorter than the absorption edge of the insulating film according to the material of the insulating film;
A circuit pattern substrate inspection apparatus using a charged particle beam.

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