JP4836626B2 - Semiconductor substrate inspection method, semiconductor substrate inspection apparatus, semiconductor substrate evaluation method, and semiconductor substrate evaluation apparatus - Google Patents

Description

  The present invention relates to a semiconductor substrate inspection method for detecting defects in a semiconductor substrate using photoluminescence, and an inspection apparatus for detecting defects in a semiconductor substrate using photoluminescence.

  When a semiconductor integrated circuit is formed on a semiconductor substrate such as a silicon wafer, crystal defects present on the semiconductor substrate cause a normal operation of the semiconductor integrated circuit. In addition, with the miniaturization of semiconductor integrated circuits, minute crystal defects on a semiconductor substrate that have not been a problem in the past have become apparent as factors that hinder the normal operation of the circuit.

  For example, when the wiring rule becomes 0.35 μm, a void defect having a size of about 0.1 μm, which was not a problem with the previous design rule, became apparent. A void defect is an aggregate of atomic vacancies formed during silicon crystal growth. The form of the void defect is a regular octahedral structure with a side of about 0.1 μm (see, for example, Non-Patent Document 1).

  It is known that the void defect has a unique distribution depending on the crystal growth conditions in the silicon crystal (see, for example, Non-Patent Document 2).

  FIG. 1 schematically shows a typical defect distribution in a silicon ingot. Referring to FIG. 1, the silicon ingot is roughly classified into four regions (region A, region B, region C, and region D) from the top. Of the above four regions, region C is a substantially defect-free region, but regions A, B, and D are regions where defects occur. It is known that the type and distribution of defects are determined by the growth rate V of the silicon crystal and the ratio V / G of the temperature gradient G at the solid-liquid interface (see, for example, Non-Patent Document 3).

  For example, a void defect occurs when the value of V / G is large and occurs mainly in the region A in FIG. Further, when the value of V / G is decreased, another type of defect such as that seen in the region B occurs. In the silicon belonging to the region B, stacking faults occur when an oxidation heat treatment is performed after processing the wafer. The defects found in the region B are called oxidation induced stacking faults (sometimes called OSF for short). The region B is called an OSF ring region because it is distributed in a ring shape on the silicon wafer.

  If the value of V / G is further reduced, a defect-free region as seen in region C can be formed. However, if the value of V / G is further reduced, a new region as shown in region D is obtained. Defects occur. The defect generated in the region D is a dislocation loop in which interstitial silicon atoms are aggregated.

  The ratio of the region C that is a defect-free region to the entire silicon ingot is limited. Further, it takes a great deal of man-hours to specify the location of the region C in the ingot, and it is necessary to keep the pulling speed low in order to form a defect-free region. Therefore, it is substantially difficult to use only the region C which is a defect-free region for a product (wafer).

  For this reason, for example, it is preferable that the region A that has a defect (void defect) but can be formed at a high pulling rate is effectively used. For example, since a silicon wafer formed from the region A is used for a fine device having a wiring rule of 0.35 μm or later, a method of annealing the wafer to eliminate void defects has been proposed. Such a wafer may be called an annealed wafer.

  As described above, in order to effectively use the silicon ingot, it is necessary to specify the above-described region. In this case, since the OSF ring region in the region B becomes a large boundary between the region A and the region C, it is particularly important to specify the OSF ring region.

  In the OSF ring region (region B), minute oxygen precipitates are formed at the stage of crystal growth. Therefore, when silicon related to the OSF ring region is oxidized, interstitial atoms aggregate with oxygen precipitates as nuclei, and an extrinsic stacking fault is formed. Since such stacking faults are accompanied by lattice distortion, the OSF ring region can be identified by X-ray topography. Therefore, there has been a case where X-ray topographic measurement is performed after the silicon wafer is heat-treated (oxidation treatment) to specify the OSF ring region.

In addition, since the OSF ring region has a high oxygen precipitate density even before the heat treatment (oxidation treatment), the oxygen precipitate density after the heat treatment is significantly higher than those in the regions A and C. Therefore, the OSF ring region may be specified by evaluating the oxygen precipitate density after the heat treatment (oxidation treatment).
Itsumi et al. Appl. Phys. 78 (1995) 5984. Hyun-Soo et al., Jpn. J. et al. Appl. Phys. 40 (2001) L1286 V. V. Voronkov et al., J. MoI. Crystal Growth 59 (1982) 625.

  However, the conventional methods for specifying the OSF ring region require a heat treatment (oxidation treatment) in any case, so that it takes a long time to implement the method.

  For example, for conventional oxygen precipitate evaluation, it was necessary to treat silicon at a temperature of 600 ° C. to 800 ° C. for several hours and then to treat it at a temperature of 1000 ° C. to 1100 ° C. for several tens of hours. In this case, it takes several days only for the evaluation of the area B. Furthermore, since the conventional method for detecting the region B requires heat treatment, it has been difficult to inspect the product wafer. For this reason, it has been difficult to perform process management related to the inspection of a defective area. Therefore, a change in the defect region due to a defect in crystal growth has caused problems such as deterioration of the characteristics of the semiconductor device and a decrease in the yield of manufacturing the semiconductor device.

  In view of this, the present invention has a general object to provide a new and useful semiconductor substrate inspection method and semiconductor substrate inspection apparatus that solve the above-described problems.

  A specific object of the present invention is to provide a semiconductor substrate inspection method for detecting defects in a semiconductor substrate with good efficiency and a semiconductor substrate inspection apparatus for detecting defects in a semiconductor substrate with good efficiency.

In the first aspect of the present invention, the above-described problems are detected in the irradiation step of irradiating the semiconductor substrate with excitation light, the detection step of detecting light emission by photoluminescence due to the irradiation of the excitation light, and the detection step. A data processing step for processing the emission data to detect defects in the semiconductor substrate, and detecting the emission by irradiating the excitation light until the temporal change rate of the emission intensity becomes substantially constant. by, method of inspecting a semi-conductor substrate you detect the defect, the semiconductor substrate is a silicon substrate, the defects, the inspection method of a semiconductor substrate is a defect in the OSF ring region and resolve.

  In the above inspection method, the excitation light is irradiated until the temporal change rate of the intensity of the emitted light becomes substantially constant, so that it is easy to detect a defect by detecting the emitted light. For this reason, there is an effect that the defect of the semiconductor substrate can be detected without performing a specific process such as a heat treatment or an oxidation process. In addition, it becomes possible to perform process management related to the inspection of the defect area, and the yield of manufacturing semiconductor devices can be improved.

In the second aspect of the present invention, the above-mentioned problem is detected by the irradiation unit that irradiates the semiconductor substrate with excitation light, the detection unit that detects light emission by photoluminescence due to the irradiation of the excitation light, and the detection unit. A data processing unit that processes emission data to detect defects in the semiconductor substrate, and detects the emission by irradiating the excitation light until the temporal change rate of the emission intensity becomes substantially constant. by, there is provided an inspection apparatus of a semi-conductor substrate that is configured to detect the defect, the semiconductor substrate is a silicon substrate, the defects, the inspection apparatus of a semiconductor device is defective in the OSF ring region ,Resolve.

  According to the above inspection apparatus, since the excitation light is irradiated until the temporal change rate of the emission intensity becomes substantially constant, it becomes easy to detect a defect by detecting the emission. For this reason, there is an effect that the defect of the semiconductor substrate can be detected without performing a specific process such as a heat treatment or an oxidation process. In addition, it becomes possible to perform process management related to the inspection of the defect area, and the yield of manufacturing semiconductor devices can be improved.

In the third aspect of the present invention, the above-described problems are detected by the irradiation step of irradiating the silicon substrate with excitation light, the detection step of detecting light emission by photoluminescence due to the irradiation of the excitation light, and the detection step. A data processing step for processing emission data, and in the irradiation step, the silicon substrate is irradiated with the excitation light for a period of time until the time change rate of the emission intensity becomes substantially constant. The problem is solved by a semiconductor substrate evaluation method that detects defects in the OSF ring region inside .

  In the semiconductor substrate evaluation method described above, the excitation light is irradiated until the temporal change rate of the emission intensity becomes substantially constant, so that the accuracy of evaluation of the semiconductor substrate is improved.

In the fourth aspect of the present invention, the above-described problem is detected by the irradiation unit that irradiates the silicon substrate with excitation light, the detection unit that detects light emission by photoluminescence due to the irradiation of the excitation light, and the detection step. A data processing unit for processing luminescence data, and the irradiating unit irradiates the excitation light for a period of time until the time change rate of the intensity of the luminescence becomes substantially constant, thereby the silicon substrate. This is solved by a semiconductor substrate evaluation apparatus that detects defects in the OSF ring region therein.

  In the semiconductor substrate evaluation apparatus described above, since the excitation light is irradiated until the time change rate of the emission intensity becomes substantially constant, the evaluation accuracy of the semiconductor substrate is good.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the inspection method of the semiconductor substrate which detects the defect of a semiconductor substrate with favorable efficiency, and the inspection apparatus of the semiconductor substrate which detects the defect of a semiconductor substrate with favorable efficiency.

  In the semiconductor substrate inspection method (inspection apparatus) according to the present invention, a defect of the semiconductor substrate is detected using a photoluminescence method. The photoluminescence method is a method of irradiating a semiconductor substrate to be measured, for example, a semiconductor substrate made of a silicon wafer with a laser beam having a wavelength higher in energy than the band gap of silicon, and measuring emitted light. When light having a photon energy larger than the band gap of a semiconductor is used as an excitation source and the semiconductor is irradiated with excitation light and absorbed, non-equilibrium electrons and holes are generated. They go through several metastable states and return to their initial thermal equilibrium by further recombination. The light emitted by the luminescent recombination in this process is light emission by photoluminescence, and a method of analyzing / inspecting a sample by detecting the light emission is called a photoluminescence method.

  FIG. 2 is a typical photoluminescence spectrum of a silicon wafer (silicon single crystal). The light emission shown in this figure is called band edge light emission, and is light emission in the recombination process of free electrons in the conduction band and free holes in the valence band.

  For example, when a defect exists in a silicon crystal, electrons or holes generated by light irradiation are trapped in the defect, so that the intensity of band edge emission decreases. Therefore, a decrease in the band edge emission intensity indicates that there are defects in the crystal.

  For this reason, it is possible to detect crystal defects in the semiconductor substrate (silicon wafer) by measuring the two-dimensional distribution (in-plane distribution) of the emission intensity related to the photoluminescence of the semiconductor substrate (silicon wafer). For example, it is specified whether the silicon wafer includes a defective region (such as region A or region B shown in FIG. 1) or a non-defective region (region C shown in FIG. 1). Is possible. Further, when the silicon wafer includes the OSF ring region, it is possible to specify the location of the OSF ring region.

  However, it has heretofore been difficult to detect crystal defects due to the difference in emission intensity by such a photoluminescence method. This is because the difference between the emission intensity at the portion where no defect exists and the emission intensity at the portion where the defect exists is slight.

  For this reason, there has been a case in which a method of facilitating the detection of defects by heat-treating the semiconductor substrate has been taken, but there is a problem that the heat treatment takes time.

  Therefore, the inventors of the present invention have made extensive studies on a method for detecting defects by a photoluminescence method without heat-treating (oxidizing) the semiconductor substrate. As a result, as described below, the inventor of the present invention has found that the emission intensity related to photoluminescence changes with time.

  FIG. 3 is a diagram in which changes with time of emission intensity related to photoluminescence when a semiconductor substrate (silicon substrate) is irradiated with excitation light (laser light) are examined.

  Referring to FIG. 3, it can be seen that the emission intensity increases with time. Further, the speed at which the emission intensity increases becomes maximum immediately after the start of excitation light irradiation, and then gradually decreases.

  FIG. 4 is a diagram showing the results of examining the temporal change rate of the emission intensity in the case of FIG. Referring to FIG. 4, the temporal change rate of the emission intensity becomes maximum immediately after the start of excitation light irradiation, and then decreases rapidly. It was found that the time change rate became substantially constant after about 3 seconds from the start of excitation light irradiation, and hardly changed thereafter.

  Conventionally, evaluation of semiconductor substrates by photoluminescence method has been given the highest priority on evaluation efficiency (time), so it is common to measure the emission intensity after several hundred milliseconds have elapsed after the start of excitation light (laser light) irradiation. It was the target.

  On the other hand, in the defect detection according to the photoluminescence method according to the present invention, the emission can be detected by irradiating the semiconductor substrate with excitation light until the temporal change rate of the intensity of light emission related to photoluminescence becomes substantially constant. It is a feature. For this reason, it is easy to detect defects in the semiconductor substrate. In this case, the difference between the light emission intensity at the portion where no defect exists and the light emission intensity at the portion where there is a defect becomes larger than the conventional case, and the defect can be easily detected. The detection results of these defects will be described later.

  Next, a specific example of the semiconductor substrate inspection apparatus and the semiconductor substrate inspection method by the above-described photoluminescence method will be described.

  FIG. 5 is a diagram schematically showing a semiconductor substrate inspection apparatus 100 according to the first embodiment of the present invention. Referring to FIG. 5, the inspection apparatus 100 includes a holding base 101 that holds a semiconductor substrate 102, an irradiation unit 104 that irradiates the semiconductor substrate 102 with excitation light (laser light), and a detection that detects light emission of the semiconductor substrate 102. A unit 105 and a device control unit (computer) 200.

  The irradiation unit 104 is made of an Ar laser (wavelength 364 nm), for example, and has a structure for irradiating the semiconductor substrate 102 with excitation light. The excitation light emitted from the irradiation unit 104 is reflected by the reflection plate 103 and then irradiated to the semiconductor substrate 102.

  The semiconductor substrate 102 is made of, for example, a silicon substrate, and emits light by photoluminescence when irradiated with excitation light from the irradiation unit 104. Light emission related to photoluminescence of the semiconductor substrate 102 is detected by the detection unit 105.

  Further, the holding table 101 is operated in the X and Y directions orthogonal to each other by a holding table operating means (not shown), and is configured to be able to measure the distribution of light emission in the plane of the semiconductor substrate 102. ing.

  The apparatus control unit 200 has a function of controlling the operation of the inspection apparatus 100. For this reason, the apparatus control unit 200 processes the irradiation unit control unit 201 that controls the irradiation unit 104, the detection unit control unit 202 that controls the detection unit 202, and the light emission data detected by the detection unit to generate a defect. Data processing means 203 for detecting data, storage means 204 for storing data, and input / output means 205 serving as a user interface.

  In the inspection apparatus 100 described above, by detecting the light emission of the semiconductor substrate 102 by irradiating the semiconductor substrate 102 with excitation light until the temporal change rate of the light emission intensity of the semiconductor substrate 102 becomes substantially constant, The semiconductor substrate 102 is configured to detect defects.

  In this case, the irradiation time of the excitation light (laser light) of the irradiation means 104 is controlled as follows, for example. First, the irradiation time is input in advance from the input / output unit 205 and stored in the storage unit 104. The irradiation unit control unit 201 irradiates the excitation light based on the value stored in the storage unit 204 until the temporal change rate of the emission intensity of the semiconductor substrate 102 becomes substantially constant (hereinafter, in the text). Method A).

  Moreover, the irradiation time of the excitation light (laser light) of the irradiation means 104 may be controlled as follows, for example. First, the irradiation unit 104 is controlled by the irradiation unit control means 201, and the semiconductor substrate 102 is irradiated with excitation light. Here, the intensity of light emitted from the semiconductor substrate 102 is detected by the detection unit 105 controlled by the detection unit control means 202. Further, the data processing means 203 processes the light emission intensity data detected by the detection unit 105, and calculates the temporal change rate of the light emission intensity. The irradiation unit control unit 201 irradiates the semiconductor substrate 102 with excitation light until a time when the data processing unit 203 determines that the rate of change in emission intensity over time is constant (hereinafter, method B). In this case, there is no need to input the irradiation time of the excitation light in advance, and there is an effect that the irradiation time can be controlled according to various changes in measurement conditions.

  Next, a semiconductor substrate inspection method using the above-described inspection apparatus 100 will be described based on the flowchart of FIG.

  First, in the step shown in Step 1 (denoted as S1 in the figure, the same applies hereinafter), the irradiation unit 104 is controlled by the irradiation unit control unit 201. For example, excitation light composed of Ar laser light having a wavelength of 364 nm is emitted from the semiconductor. The substrate 102 is irradiated. In this case, the semiconductor substrate 102 is irradiated with excitation light by the method A or the method B described above until the temporal change rate of the intensity of light emission related to the photoluminescence of the semiconductor substrate 102 becomes substantially constant.

  In the step shown in step 2, light emission of the semiconductor substrate 102 due to irradiation of excitation light is detected by the detection unit 105 controlled by the detection unit control means 202.

  In the step shown in Step 3, the light emission data detected by the detection unit 105 is processed by the data processing unit 203, and a defect of the semiconductor substrate 102 is detected.

  In this case, as described above, the data processing unit 203 may calculate a time at which the rate of change of the emission intensity with time is constant.

  In the above semiconductor substrate inspection method (inspection apparatus), it is possible to detect defects in the semiconductor substrate without subjecting the semiconductor substrate to substantial processing such as heat treatment or oxidation treatment. It is a feature.

  Conventionally, there has been a case where a semiconductor substrate is subjected to heat treatment (oxidation treatment) in order to facilitate defect detection. For example, in order to specify the OSF ring region (region B in FIG. 1), a method of forming a stacking fault in the OSF ring region by oxidizing silicon may be used. In addition, oxidation treatment may be performed to further increase the density of oxygen precipitates in the OSF ring region.

  On the other hand, in the case of the present embodiment, since it is not necessary to perform a substantial inspection process (heat treatment, oxidation process, etc.) on the semiconductor substrate, it is possible to detect defects efficiently. In addition, since it is possible to detect defects in the semiconductor substrate that is the product (semiconductor device), the process management of the semiconductor device manufacturing process related to the inspection of the defect area is performed by using the inspection method (inspection apparatus) according to this embodiment. It becomes possible. Therefore, it is possible to improve the manufacturing yield of the semiconductor device.

Next, the detection result of the defect using said inspection method (inspection apparatus) is demonstrated based on FIGS. In the following detection results, a p-type (B-added) silicon wafer (resistivity: 10 Ω · cm) having a diameter of 200 mm is used for the semiconductor substrate 102. Further, C (carbon) and N ₂ (nitrogen) may be added to the silicon wafer as impurities. Further, an Ar laser (wavelength 364 nm) is used as the irradiation unit 104. The laser irradiation time is 3 seconds.

  FIG. 7 is a schematic diagram in which light emission intensity related to photoluminescence detected by the substrate inspection method according to the present embodiment is visualized in light and dark (black and white). In the figure, the portion that appears black is the portion with low emission intensity, which is considered to indicate a defect.

  Referring to FIG. 7, in the silicon wafer shown in this figure, a portion where the emission intensity decreases in a donut shape is recognized, which is considered to indicate a crystal defect (defect in the OSF ring region) of the silicon wafer. It is done.

  FIG. 8 shows the light emission intensity related to the photoluminescence of the silicon substrate as a profile with the distance from the wafer center as the horizontal axis.

  Referring to FIG. 8, it can be seen that the emission intensity falls in a region of about 60 to 80 mm from the center of the wafer. This is because a crystal defect exists in the region, and is considered to be a defect in the OSF ring region.

  FIG. 9 is a bird's-eye view showing the light emission intensity related to the photoluminescence of the silicon substrate. Referring to FIG. 9, as described in the case of FIG. 8, the region where the emission intensity is reduced on the ring is about 60 to 80 mm from the wafer center. That is, the defect of the OSF ring region was confirmed more clearly in this drawing.

  FIG. 10 shows another method for inspecting a silicon wafer produced by cutting out from substantially the same position in the same lot as the silicon wafer used in the inspection of FIGS. It is the figure which showed the result of having performed. In the case shown in this figure, the silicon wafer is subjected to heat treatment (oxidation treatment) at 780 ° C. for 3 hours and further at 1000 ° C. for 16 hours, and the scattering of infrared rays is examined.

  Referring to FIG. 10, even in the case shown in this figure, defects (OSF ring region defects) were confirmed in the region 60 to 80 mm from the wafer center, as in the case shown in FIG. 8 or FIG. 9. As a result, it was confirmed that the defect could be detected by the inspection method and the inspection apparatus according to this example.

  FIG. 11A and FIG. 11B are bird's-eye views comparing the difference in emission intensity when the laser irradiation time is changed in the substrate inspection method according to the present embodiment. In FIG. 11A, the irradiation time is 3 seconds, and in FIG. 11B, the irradiation time is 100 ms.

  Referring to FIGS. 11A and 11B, when the irradiation time shown in FIG. 11A is 3 seconds, the emission intensity drops in the area indicated by the arrow (the area of about 60 to 80 mm from the wafer center). On the other hand, when the irradiation time shown in FIG. 11B is 100 ms, such a drop is not observed.

  When the laser irradiation time is short, the temporal change rate of the emission intensity is not sufficiently converged, and the emission intensity is strong (no defect) or the emission intensity is weak (there is a defect). This is probably because the difference in the

  On the other hand, if the laser irradiation time is increased until the temporal change rate of the emission intensity becomes substantially constant, the difference in emission intensity between when there is a defect and when there is no defect is increased, and it is considered that the defect can be easily detected. .

  Further, in the present invention, for example, so-called ultraviolet rays having a wavelength of 400 nm or less (for example, an Ar laser having a wavelength of 364 nm) are used as excitation light, so that it is closer to a portion on the silicon surface side, that is, a portion where a device is actually formed. Partial defects can be selectively detected.

  On the other hand, a longer wavelength (for example, a laser beam having a wavelength of 500 nm or more) can be used in consideration of the defect detection capability without considering the depth at which the defect exists.

  In the present invention, a p-type silicon wafer has been described as an example of the semiconductor substrate, but the present invention is not limited to this. For example, it is obvious that the present invention can be applied to an n-type silicon wafer or a semiconductor substrate other than silicon (compound semiconductor, such as GaAs).

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the specific embodiments described above, and various modifications and changes can be made within the scope described in the claims.
(Appendix 1)
An irradiation step of irradiating the semiconductor substrate with excitation light;
A detection step of detecting light emission by photoluminescence due to irradiation of the excitation light;
A data processing step of processing the light emission data detected in the detection step to detect defects in the semiconductor substrate,
A method for inspecting a semiconductor substrate, wherein the defect is detected by irradiating the excitation light until the rate of change of the intensity of light emission with time becomes substantially constant, and detecting the light emission.
(Appendix 2)
The method of inspecting a semiconductor substrate according to appendix 1, wherein the semiconductor substrate is a silicon substrate.
(Appendix 3)
The semiconductor substrate inspection method according to appendix 2, wherein the semiconductor substrate is not substantially heat-treated.
(Appendix 4)
4. The method of inspecting a semiconductor substrate according to appendix 2 or 3, wherein the semiconductor substrate is not substantially oxidized.
(Appendix 5)
5. The method for inspecting a semiconductor substrate according to any one of appendices 2 to 4, wherein the defect is a defect in an OSF ring region.
(Appendix 6)
6. The semiconductor substrate inspection method according to any one of appendices 2 to 5, wherein in the irradiation step, the semiconductor substrate is irradiated with laser light having a wavelength of 400 nm or less.
(Appendix 7)
An irradiation unit for irradiating the semiconductor substrate with excitation light;
A detection unit for detecting light emission by photoluminescence by irradiation of the excitation light;
A data processing unit that processes light emission data detected by the detection unit to detect defects in the semiconductor substrate;
Inspection of a semiconductor substrate, wherein the defect is detected by irradiating the excitation light until the rate of change in intensity of light emission with time is substantially constant, and detecting the light emission. apparatus.
(Appendix 8)
The semiconductor substrate inspection apparatus according to appendix 7, wherein the semiconductor substrate is a silicon substrate.
(Appendix 9)
9. The semiconductor substrate inspection apparatus according to appendix 8, wherein the semiconductor substrate is not substantially heat-treated.
(Appendix 10)
The semiconductor substrate inspection apparatus according to appendix 8 or 9, wherein the semiconductor substrate is not substantially oxidized.
(Appendix 11)
11. The semiconductor substrate inspection apparatus according to any one of appendices 8 to 10, wherein the defect is a defect in an OSF ring region.
(Appendix 12)
12. The semiconductor substrate inspection apparatus according to any one of appendices 8 to 11, wherein the irradiation unit is configured to irradiate the semiconductor substrate with laser light having a wavelength of 400 nm or less.
(Appendix 13)
An irradiation step of irradiating the semiconductor substrate with excitation light;
A detection step of detecting light emission by photoluminescence due to irradiation of the excitation light;
A data processing step for processing the light emission data detected in the detection step,
The method for evaluating a semiconductor substrate, wherein, in the irradiation step, the excitation light is irradiated for at least a time until a temporal change rate of the intensity of the light emission becomes substantially constant.
(Appendix 14)
An irradiation unit for irradiating the semiconductor substrate with excitation light;
A detection unit for detecting light emission by photoluminescence by irradiation of the excitation light;
A data processing unit for processing the light emission data detected in the detection step,
The said irradiation part irradiates the said excitation light more than the time until the time change rate of the said light emission intensity becomes substantially constant, The evaluation apparatus of the semiconductor substrate characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the inspection method of the semiconductor substrate which detects the defect of a semiconductor substrate with favorable efficiency, and the inspection apparatus of the semiconductor substrate which detects the defect of a semiconductor substrate with favorable efficiency.

It is a figure which shows the typical defect distribution in a silicon ingot. It is a figure which shows the typical photo-luminescence spectrum of a silicon wafer. It is the figure which investigated the change by the time passage of the emitted light intensity which concerns on the photoluminescence of a silicon wafer. It is a figure which shows the time change rate of the emitted light intensity in the case of FIG. It is a figure which shows the inspection apparatus of the semiconductor substrate by Example 1 of this invention. It is a flowchart which shows the inspection method of a semiconductor substrate. It is the schematic diagram which visualized the emitted light intensity which concerns on photoluminescence with light and dark. The light emission intensity of FIG. 7 is displayed as a profile with the distance from the wafer center on the horizontal axis. FIG. 8 is a bird's eye view of the emission intensity of FIG. This is a result of confirming defects in the heat-treated silicon wafer. It is the figure (the 1) which compared the difference in the emitted light intensity by the irradiation time of a laser. It is the figure (the 2) which compared the difference in the emitted light intensity by the irradiation time of a laser.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Inspection apparatus 101 Holding stand 102 Semiconductor substrate 103 Reflector 104 Irradiation part 105 Detection part 200 Apparatus control part 201 Irradiation part control means 202 Detection part control means 203 Data processing means 204 Storage means 205 Input / output means

Claims (6)

An irradiation step of irradiating the semiconductor substrate with excitation light;
A detection step of detecting light emission by photoluminescence due to irradiation of the excitation light;
A data processing step of processing the light emission data detected in the detection step to detect defects in the semiconductor substrate,
By detecting the emission time rate of change of intensity of the light emission by irradiating the excitation light to be essentially constant, method of inspecting a semi-conductor substrate you detect the defect,
The semiconductor substrate is a silicon substrate;
The method of inspecting a semiconductor substrate, wherein the defect is a defect in an OSF ring region . Wherein in the irradiation step, the semiconductor substrate inspection method according to claim 1, wherein a wavelength or less of the laser beam 400nm is irradiated to the semiconductor substrate. An irradiation unit for irradiating the semiconductor substrate with excitation light;
A detection unit for detecting light emission by photoluminescence by irradiation of the excitation light;
A data processing unit that processes light emission data detected by the detection unit to detect defects in the semiconductor substrate;
By detecting the emission time rate of change of intensity of the light emission by irradiating the excitation light to be essentially constant, there is provided an inspection apparatus of a semi-conductor substrate that is configured to detect the defect ,
The semiconductor substrate is a silicon substrate;
The semiconductor substrate inspection apparatus , wherein the defect is a defect in an OSF ring region . 4. The semiconductor substrate inspection apparatus according to claim 3 , wherein the irradiation unit is configured to irradiate the semiconductor substrate with laser light having a wavelength of 400 nm or less. An irradiation step of irradiating the silicon substrate with excitation light;
A detection step of detecting light emission by photoluminescence due to irradiation of the excitation light;
A data processing step for processing the light emission data detected in the detection step,
In the irradiation step, the defect of the OSF ring region in the silicon substrate is detected by irradiating the excitation light for a time period until the time change rate of the emission intensity becomes substantially constant. A method for evaluating a semiconductor substrate. An irradiation unit for irradiating the silicon substrate with excitation light;
A detection unit for detecting light emission by photoluminescence by irradiation of the excitation light;
A data processing unit for processing the light emission data detected in the detection step,
The irradiation unit detects a defect in the OSF ring region in the silicon substrate by irradiating the excitation light for a time until the time change rate of the emission intensity becomes substantially constant. A semiconductor substrate evaluation apparatus.