JP4530189B2 - Method and apparatus for measuring flatness of untreated wafer of donor killer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for measuring the flatness of an untreated donor killer wafer, and in particular, irradiates light of a predetermined wavelength to make the relative dielectric constant in the wafer constant and detects the capacitance facing the wafer. A capacitance-type flatness measuring instrument that measures the flatness by calculating the distance between the wafer surface and the capacitance detection probe by arranging the probe, measuring the change in the high-frequency current value from the capacitance detection probe The present invention relates to a method and an apparatus for measuring flatness of a wafer not treated with a donor killer for measuring the flatness of a wafer surface.
[0002]
[Prior art]
Conventionally, a wafer having not been treated with a donor killer has been measured by measuring the flatness of the surface of the wafer using a capacitance type flatness measuring device. However, when the flatness of the surface of the wafer is measured using this capacitance type flatness measuring device, there is an erroneous measurement in which a non-defective product is determined as a defective product at a rate of several percent to several tens of percent per lot. This is because, in a wafer not treated with donor killer, interstitial oxygen is unevenly present inside the wafer and acts as a donor, so it is detected to be thicker or thinner than the actual wafer thickness, and based on these detected values The reason for this is thought to be the flatness.
[0003]
In addition, in the p-type as-grown wafer, particularly significant interstitial oxygen unevenness exists in a state where a portion with high electrical resistance (electrically neutral) and a portion with low electrical resistance exist in the wafer. For this reason, even though the sample is actually confirmed to have a uniform thickness with an electronic micrometer or the like, if it is a thin sample, erroneous measurement will occur. Therefore, accurate flatness data cannot be obtained unless the wafer is subjected to donor killer processing. However, when all defective donor killer processing is performed without selecting defective products that do not meet the standard of flatness from the beginning, the defective killer processing is a wasteful process for defective wafers from the beginning. It will be. Also, depending on the product specifications, there are wafers that do not require donor killer processing, but this product also has to be subjected to donor killer processing to check the flatness, which is a wasteful process. It was. For this reason, the present applicant has proposed an improvement of a measuring apparatus and a measuring method of the wafer not treated with donor killer in Japanese Patent Laid-Open No. 7-221149.
[0004]
According to the publication, as shown in FIG. 9, the capacitance type flatness measuring instrument is provided with a halogen lamp 33 having a wavelength of 1129 nm or less and an illuminance of 150,000 lux or more in the vicinity of the probe 31, so that the donor killer is not processed. The surface of the measured wafer 35 (hereinafter referred to as wafer 35) is irradiated with light. When light enters the bulk, it changes into excitation energy, and by converting the valence electrons of silicon into conduction electrons, the number of free electrons or holes generated from silicon is much greater than that of dopants and oxygen donors, and thus, like metals It becomes a state. That is, electrons are uniformly distributed in any part of the wafer 35. When the upper and lower surfaces of the wafer 35 are measured in such a state, the relative dielectric constant ε is constant everywhere. Therefore, by measuring the amount of electricity with the probe 31, the wafer 35, the probe 31a, and the wafer 35 The distance to the probe 31b can be accurately measured. Thus, the thickness of the portion of the wafer 35 can be measured by subtracting the distance between the wafer 35 and the probe 31a and the distance between the wafer 35 and the probe 31b from the distance between the probes 31a and 31b. It is described that the wafer 35 can accurately measure the flatness of the wafer 35 that has not been processed with the donor killer based on these measured values.
[0005]
[Problems to be solved by the invention]
Recently, there has been a demand for thinning a wafer on which an integrated circuit is formed with the aim of downsizing and low power consumption. Accordingly, improvement in wafer flatness is required. Therefore, there is a demand for measurement of wafer flatness with high accuracy and high reliability of measurement values. However, according to the above-mentioned Japanese Patent Application Laid-Open No. 7-221149, as a measuring apparatus and measuring method for a wafer not treated with donor killer, the conventional drawbacks are solved and satisfied, but the above-mentioned demand is achieved. For this purpose, further improvements are required. For this reason, in the new high-precision model, the measurement points on the wafer surface and the probe response frequency (Hz) are almost three times that of the conventional model. In this new high-precision model, the flatness of a wafer whose thickness was confirmed to be constant with an electronic micrometer or the like in advance was measured as disclosed in JP-A-7-221149. As shown in FIG. 5, there was a problem that a top hat groove shape and a spiral groove shape in which valleys (T) and peaks (Y) appear, and a stable measurement could not be performed.
[0006]
The present invention relates to a method and an apparatus for measuring the flatness of an untreated donor killer wafer, paying attention to the above-mentioned conventional problems, and in particular, by increasing the measurement points on the wafer surface and the probe response frequency (Hz). An object of the present invention is to provide a method and apparatus for measuring the flatness of an untreated donor killer wafer that can measure the flatness of the surface of the wafer with a stable accuracy even in a highly accurate model.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a method for measuring the flatness of an untreated donor killer wafer according to the present invention uses a capacitance flatness measuring device to measure the flatness of the surface of an untreated donor killer wafer. In the method for measuring the flatness of a processed wafer, the surface of the rotating donor killer unprocessed wafer is faced with the probe of the capacitance-type flatness measuring device, and energy equal to or greater than the band gap is provided immediately upstream of the probe facing portion. When measuring by irradiating light of the wavelength to be applied, the measurement of abnormalities (spiral shape) due to vibrations coming from the device / environment is suppressed by vibration-proofing the light source support of the irradiation light, and the donor killer unprocessed wafer Of the surface of the wafer, the front side in the rotational direction of the unprocessed wafer of the donor killer than the measurement position by the probe, and the measurement position The illumination light is irradiated to a position away beyond the amplitude width of the irradiation light in al the surface is obtained by the so that to measure. In this case, it is desirable to measure the flatness of the surface of the wafer by setting the illuminance of the light irradiating the surface of the untreated wafer with the donor killer to at least 400,000 lux which is greater than the band gap. Further, the vibration of the irradiation light source on the surface of the untreated wafer of the donor killer is suppressed to a maximum of 2 mm or less, preferably 1 mm or less on the wafer surface, and the synchronization with the apparatus vibration is cut off. It is desirable to do.
[0008]
An apparatus for measuring the flatness of an untreated donor killer wafer according to the present invention is a flatness measuring apparatus for an untreated donor killer wafer that measures the flatness of the surface of the untreated donor killer wafer using a capacitance type flatness measuring device. , The probe of the capacitance-type flatness measuring device facing the surface of the rotating donor killer unprocessed wafer, and light having a wavelength that gives energy equal to or greater than the band gap at the portion immediately upstream of the probe facing portion beyond a light source for irradiating the web over wafer surface, the vibration width of the irradiation light in the wafer surface from and the measuring position to a front side of the rotational direction of the donor killer unprocessed wafer than the measurement position by the probe a mounting support for the irradiation light from the light source to a remote location for supporting the light source so as to irradiate Te is interposed support portion mounting this And a vibration isolating means is obtained by a measurable by suppressing illuminance fluctuation of the light irradiation surface on the web over wafer irradiated from the light source. The light source mounting support part sandwiches a buffer plate with a fixed plate with respect to a fixed part such as a floor or a measuring instrument case, and stands up from one fixed plate to support the light source. What is necessary is just to comprise so that the vibration from a fixing | fixed part to a light source may be prevented.
[0009]
[Action]
According to the above configuration, when measuring the flatness of the unprocessed wafer with the donor killer, the measurement device is included in the portion that supports the light source so that the light of the predetermined wavelength irradiated on the surface of the wafer does not vibrate on the irradiation surface. It is necessary to suppress external vibration. For this reason, in the support device that supports the light source, the material of the buffer plate such as a rubber plate is inserted into both the upper and lower surfaces of the floor or the upper and lower surfaces of the mounting plate of the measuring instrument and is sandwiched between the fixed plates. . A support rod is erected from one side of the fixed plate to support the light source. As a result, the support rod that supports the light source does not transmit vibration from the upper fixed plate on which the support rod is erected and from the lower fixed plate on the opposite side, so the vibration of the light source is reduced. Accordingly, the fluctuation width of the light irradiating the surface of the wafer is reduced, and fluctuations in the surface illuminance of the wafer can be suppressed. Therefore, even in models with improved flatness measurement accuracy, the light source is attached by a support device using a buffer plate that suppresses vibration, so that the fluctuation width of the irradiated light is reduced, and the wafer light is reduced. Since the electrons in the irradiated area are stably and uniformly distributed without moving, it has become possible to measure accurately without causing a measurement abnormality due to external vibration including the measuring instrument.
[0010]
In such a situation, by increasing the illuminance of the light irradiating the wafer surface to at least 400,000 lux, which is greater than the band gap, even if the p-type as-grown wafer has significant interstitial oxygen unevenness, More free electrons or holes generated from silicon than oxygen donors and even more than before the illuminance increase, it becomes like a metal, and electrons are evenly distributed in every part of the wafer, so there is a variation in measurement. Get smaller. The illuminance of the irradiation light may be set to 400,000 lux or more. Specifically, the relationship between the intensity of illuminance and the occurrence of a top hat groove or the like is obtained for each wafer type, and is set based on this data. Well, in reality, the detection of the top hat-shaped groove is eliminated by irradiating 1 million lux light.
[0011]
Further, the irradiation position of the light whose vibration width is suppressed is irradiated in the vicinity of the probe on the surface of the wafer to be measured and at a distance away from the probe beyond the vibration width of the light. At this time, the irradiation position of the light is a maximum of 2 mm or less, preferably 1 mm or less of the vibration width of the light, and within 10 mm from a position where the light does not hit the probe even if the light vibrates (position exceeding 2 mm). , The overall temperature of the probe is stabilized, the accuracy is high, and high-precision measurement is possible.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a method and apparatus for measuring flatness of an untreated donor killer wafer according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same parts as those in the prior art are denoted by the same reference numerals and description thereof is omitted.
[0013]
FIG. 1 is an overall conceptual side view of a flatness measuring apparatus 1 for an untreated donor killer wafer according to the present invention. FIG. 2 is a side view of the light source support device of the flatness measuring device 1. FIG. 3 is a partial perspective view of the flatness measuring device 5.
[0014]
In FIG. 1, a flatness measuring device 1 for an untreated donor killer wafer includes a light source device 3 and a capacitance type flatness measuring device (hereinafter referred to as a flatness measuring device 5).
[0015]
The light source device 3 includes a light source support device 11 attached to the floor 7 and a light source 13 attached to the light source support device 11 and capable of adjusting the irradiation position.
[0016]
In FIG. 2, the light source support device 11 includes a buffer plate 15, an upper fixing plate 17, a lower fixing plate 19, a support bar 21, and a connecting bolt 23.
[0017]
The buffer plate 15 is inserted both between the floor 7 and the upper fixed plate 17 and between the floor 7 and the lower fixed plate 19. In this embodiment, the buffer plate 15 is a rubber plate material having a thickness of 5 mm to 8 mm. The buffer plate 15 is made of a synthetic rubber material. However, a rubber material such as natural rubber and synthetic rubber, a polymer resin such as urethane, plastic, and nylon, or a synthetic resin material may be used.
[0018]
A support bar 21 is erected on the upper fixing plate 17. As shown in FIG. 1, a plurality of support arms 21a and 21b are rotatably attached to the support bar 21. As shown in FIG. That is, joints 21c and 21d that allow the angle or length of both to be adjusted as necessary are inserted between the support rod 21 and the support arms 21a and 21b, and are fixed at positions adjusted by the bolts 27. Yes. Thereby, the irradiation position of the light source 13 can be arbitrarily adjusted by the support rod 21, the support arms 21a and 21b, and the joints 21c and 21d.
[0019]
As shown in FIG. 2, the connecting bolt 23 passes through holes 23 a formed in the upper fixing plate 17, the buffer plate 15, the floor 7, and the lower fixing plate 19, and is screwed into the nut 24. Yes. The connecting bolt 23 fastens the buffer plate 15 inserted between the floor 7 and the upper fixing plate 17 and between the floor 7 and the lower fixing plate 19. Further, the connecting bolt 23 has a predetermined clearance Ra with respect to the hole 23a formed in each of the connecting bolts 23 so as not to contact the floor 7.
[0020]
As described above, since the buffer plate 15 is inserted between both the floor 7 and the upper fixing plate 17 and between the floor 7 and the lower fixing plate 19, the buffer plate 15 stands on the upper fixing plate 17. The vibration to the support bar 21 provided is bolted from the upper fixed plate 17 to the support bar 21 by the buffer plate 15 inserted on the upper side and from the lower fixed plate 19 to the support bar 21 by the lower buffer plate 15 inserted. Is not transmitted to the upper fixed plate 17 through the support rod 21, and the support bar 21 is completely cut off from the floor 7. Thereby, the vibration width of the light 13 a from the light source 13 is suppressed to 2 mm or less at the maximum at the measurement position on the surface of the wafer 35.
[0021]
The light source 13 has a support arm 21a on the support rod 21, a support arm 21b on the support arm 21a, or a light source 13 on the support arm 21b, and the irradiation position at each location or a required location via joints 21c and 21d. It is attached to be adjustable. The light source 13 is a halogen condensing lamp or fiber illumination and has an illuminance of 400,000 lux. As shown in FIG. 3, the irradiation position of the light 13 a from the light source 13 is the upper surface of the wafer 35, and the position to be measured is irradiated at a position near the probe 31. For example, when the wafer 35 is rotated counterclockwise (arrow Ga) to measure the flatness of the wafer 35, the irradiation position is on the front side (Lif) of the rotation direction (Ga) with respect to the currently measured position, Irradiation is made at a position within 10 mm at the maximum from a position away from the measurement position of the probe 31 by a distance Sa (2 mm) at the minimum. As a result, as indicated by the one-dot chain line and the solid line, even if the light 13a on the wafer vibrates with the vibration width Sb (within 2 mm at the maximum), the probe 31 is irradiated so that the light 13a does not strike. Since the light 13a does not strike the probe 31, the temperature of the entire probe 31 is stabilized, the accuracy is high, and high-precision measurement is possible.
[0022]
In the above, an example in which only the front side of the measurement position of the probe 31 in the rotation direction in which the wafer 35 rotates is shown. The irradiation position of the light 13a may be irradiated from the measurement position of the probe 31 on both the front side (Lif) and the rear side (Lib) in the direction in which the wafer 35 rotates. At this time, the irradiation position of the light 13a is more stable when simultaneously irradiated from the front side (Lif) and the rear side (Lib) within 10 mm from the position where the light beam 13a does not hit the probe 31 (position exceeding 2 mm). good. In addition, the irradiation position of the light 13a is measured either when the wafer 35 is swung by irradiating the front side (Lif) of the measurement position to be measured and the rear side (Lib) of the opposite side. The measurement position is irradiated, and it is possible to measure even when rocking.
[0023]
The flatness measuring device 5 includes a capacitance sensor probe 31, an ammeter (not shown), a high-voltage AC voltage generator (not shown), and a flatness measuring body 29. The probe 31 includes an upper probe 31 a disposed on the upper side of the wafer 35 and a lower probe 31 b disposed on the lower side of the wafer 35. The flatness measuring device 5 causes a high-frequency current to flow through the upper probe 31a and the lower probe 31b disposed with the wafer 35 interposed therebetween at a measurement point position set in advance on the wafer 35, and a current value from an ammeter (not shown). The flatness is measured from the change in the distance between the wafer 35 and the upper probe 31a and the distance between the wafer 35 and the lower probe 31b. The measurement points on the surface of the wafer 35 are 400 points on the circumference, and the conventional 1/2 pitch in the circumferential direction. As a result, the total measurement points are approximately three times that of the conventional example. The probe response frequency is 750 Hz, almost three times that of the conventional example.
[0024]
The following confirmation test was performed by the above measurement method.
(1) Confirmation test 1,
As shown in FIG. 10, the illumination intensity from the light source 13 shown in FIG. 3 is from the conventional 200,000 lux using the wafer 35 in which the top hat shape and the spiral shape characterized by the shape of the center part being depressed are formed. Raised to 400,000 lux. As a result, the top hat shape in which peaks (Y) and valleys (T) appear as shown in FIG. 4 disappears, but the spiral shape in which spirals (R) appear as shown in FIG. 4 still remains. It was. One of the reasons for the disappearance of the top hat shape was that the measurement points on the wafer surface and the probe response frequency (Hz) were almost tripled compared to the conventional method. By changing from 200,000 lux to 400,000 lux, the number of free electrons or holes generated from silicon is much greater than that of dopants and oxygen donors, and the state of metal increases and is uniform in any part of the wafer. This is probably due to the distribution of electrons. Second, the irradiation position of the light 13a is within 10 mm from the front side in the direction in which the wafer 35 rotates, that is, the position where the light 13a does not hit the probe 31 at a position to be measured in the future (position exceeding 2 mm). Irradiate the place. This is probably because the probe 31 is prevented from being exposed to the light 13a, so that the entire temperature of the probe 31 is stabilized and the accuracy of the measurement accuracy is increased. Further, it is considered that the vicinity of the probe 31 is irradiated with high light illuminance, so that electrons are uniformly distributed at the measurement position.
[0025]
(2) Confirmation test 2,
Next, the light source 13 shown in FIG. 3 is supported by being isolated by the light source support device 11 of FIG. 1 so that the spiral shape disappears, and the vibration of the light 13a having a predetermined wavelength from the light source 13 is suppressed. Confirmation of irradiating the upper surface of the wafer 35 was performed. In other words, the buffer bar 15 is inserted between the floor 7 and the upper fixing plate 17 and between the floor 7 and the lower fixing plate 19, and the support bar 21 fixed to the upper fixing plate 17. The vibration width of the light 13 a from the light source 13 supported via the upper surface of the wafer 35 was suppressed to 2 mm or less at the maximum on the upper surface of the wafer 35. As a result, the spiral shape in which the remaining spiral (R) as shown in FIG. 4 appears disappeared as shown in FIG. This is because the wafer 35 is rotated or oscillated at the time of measurement, but the vibration of the light 13a irradiating the wafer 35 at that time (caused by external vibration including the measuring device) is reduced, and the wafer 35 is in a stable position. It is considered that the spiral shape disappeared because the energy equivalent to the band gap of the portion irradiated on the upper surface of the wafer 35 was uniformly applied. Further, when the spiral (R) appeared, the vibration width of the light 13a was changed and confirmed. From this result, it was confirmed that the spiral shape disappears if the maximum is 2 mm or less and the vibration from the measuring device is cut off, but preferably a better measurement shape can be obtained if it is 1 mm or less.
[0026]
(3) Confirmation test 3,
In the confirmation test 3, the measurement apparatus improved by incorporating the results of the confirmation test 1 and the confirmation test 2 was implemented. First, as a result of performing the flatness measurement of the wafer 35 before the heat treatment in the state without light irradiation using the improved measuring apparatus, a measurement of a top hat shape in which the periphery of the central portion is depressed as shown in FIG. 6 is obtained. It was. Next, heat treatment (temperature: 650 ° C., time: 30 minutes) is performed using the wafer 35 to improve the flatness of the wafer 35 before the heat treatment and the flatness of the wafer 35 subjected to the heat treatment. A verification test was carried out by comparing with the device irradiated with light. The verification was performed using two wafers 35. As a result, the flatness shape of the wafer 35 before the heat treatment as shown in FIG. 7 is almost the same as the flatness shape of the wafer 35 after the heat treatment as shown in FIG. There was found. From this result, it was found that measurement with higher accuracy is possible by measures against vibration of light irradiation performed in the confirmation test 2 and an increase in illuminance in the confirmation test 1.
[0027]
From the above confirmation, in the flatness measuring apparatus 1 of the unprocessed wafer for the donor killer, the light source 13 is supported by the light source support apparatus 11 while being vibrated, and the light 13a having a predetermined wavelength from the light source 13 has its vibration width suppressed. The upper surface of the surface of the wafer 35 to be measured is irradiated. The irradiated position is a position in the vicinity of the probe 31 of the capacitance type flatness measuring device and a position (Sa) away from the probe 31 beyond the vibration width of the light 13a. Irradiating the top. It was confirmed that the illuminance of the irradiated light 13a can be measured accurately and accurately by irradiating the wafer 35 with light 13a having a band gap of at least 400,000 lux and measuring the flatness of the surface of the wafer 35.
[0028]
In the above embodiment, the light source support device 11 of the light source device 3 is provided with the buffer plate 15 on the upper and lower surfaces of the floor 7, but may be attached to the flatness measuring body 29 as shown in FIG.
[0029]
In the flatness measuring apparatus for the donor killer unprocessed wafer in such an embodiment, both the upper and lower surfaces of the floor or the upper and lower surfaces of the measuring device mounting plate are used to suppress the vibration of the supporting device that supports the light source. Insert the buffer plate into and clamp it with the fixed plate. A support rod is erected from one side of the fixed plate to support the light source. The vibration to the support bar is not transmitted from the upper fixing plate to the support bar and from the lower fixing plate to the upper fixing plate, and is completely cut off from the floor. As a result, vibration is not transmitted to the support rod that supports the light source standing on the fixed plate, the vibration width of the light from the light source can be suppressed, and the electrons at the location where the light of the wafer is irradiated do not move. Since the distribution is stable and uniform, a stable current value can be measured and the accuracy is improved.
[0030]
Also, by increasing the illuminance of the light irradiating the surface of the wafer, the number of free electrons or holes generated from silicon becomes much larger than that of dopants and oxygen donors, resulting in a metal-like state. In addition, since the electrons are uniformly distributed, the variation in measurement is reduced. In addition, by irradiating 10 mm from the position where the light does not hit the probe even if the light irradiating the wafer vibrates, the temperature of the entire probe is stable, high accuracy, and high accuracy measurement is possible. Become.
[0031]
【The invention's effect】
As described above, the present invention provides a probe of the capacitance-type flatness measuring device which is disposed facing the surface of a rotating donor killer unprocessed wafer, and a band gap or more at a portion immediately upstream of the probe facing portion. A light source for irradiating the surface of the wafer with light having a wavelength for imparting energy; and a vibration isolating means interposed in a mounting support portion of the light source, and the illuminance fluctuation of the light irradiation surface on the wafer irradiated from the light source. Since measurement is possible by suppressing the measurement, the wafer surface flatness can be measured with a stable accuracy even with high-accuracy measurement points on the wafer surface and high-accuracy models with a high probe response frequency (Hz). An effect is obtained.
[Brief description of the drawings]
FIG. 1 is an overall conceptual side view of an apparatus for measuring flatness of an untreated donor killer wafer in an embodiment of the present invention.
FIG. 2 is a side view of a support device of a flatness measuring device for an untreated donor killer wafer in an embodiment of the present invention.
FIG. 3 is a partial perspective view of a measuring unit of the flatness measuring apparatus of the present invention.
FIG. 4 is a diagram showing the flatness measured when the light illuminance in Confirmation Test 1 is set to 400,000 lux.
FIG. 5 is a diagram of measuring the flatness of a support device that suppresses vibrations in confirmation test 2;
FIG. 6 is a shape diagram in which the flatness of a wafer is measured before being subjected to the heat treatment of confirmation test 3 and in a state where light is not irradiated.
7 is a diagram showing the shape of a wafer measured for flatness before being subjected to the heat treatment of confirmation test 3. FIG.
FIG. 8 is a shape diagram of the measured flatness of a wafer measured after the heat treatment of confirmation test 3;
FIG. 9 is a partial conceptual perspective view of a flatness measuring apparatus for a conventional donor killer unprocessed wafer.
FIG. 10 is a shape diagram of the measured flatness of a wafer when initially measured by the flatness measuring apparatus with improved accuracy according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Donor killer unprocessed wafer flatness measuring device 3 Light source device 5 Capacitance type flatness measuring device, flatness measuring device 5
7 Floor 11 Light source support device 13 Light source 13a Light from light source 15 Buffer plate 17 Upper fixing plate 19 Lower fixing plate 21 Supporting rod 21c Joint 23 Connection bolt 31 Probe 35 Measured wafer (wafer)

Claims (5)

In the flatness measurement method of a donor killer unprocessed wafer, which measures the flatness of the surface of the donor killer unprocessed wafer using a capacitance type flatness measurement device,
The surface of the rotating donor killer unprocessed wafer is made to face the probe of the capacitance type flatness measuring device, and light having a wavelength that gives energy more than the band gap is irradiated to the portion immediately upstream of the probe facing portion. When measuring, by suppressing the illuminance fluctuation of the light irradiation surface by shaking the light source support portion of the irradiation light ,
Out of the surface of the donor killer unprocessed wafer, the front of the donor killer unprocessed wafer in the rotational direction from the measurement position by the probe, and away from the measurement position beyond the amplitude width of the irradiation light on the surface the irradiation light is irradiated, measured to flatness measurement method of the donor killer unprocessed wafer, comprising Rukoto in position.   2. The donor killer according to claim 1, wherein the flatness of the surface of the wafer is measured by setting the illuminance of light irradiated to the surface of the unprocessed wafer of the donor killer to at least 400,000 lux that is equal to or greater than the band gap. Method for measuring the flatness of unprocessed wafers.   The vibration of the irradiation light on the surface of the donor killer unprocessed wafer is suppressed to a maximum of 2 mm or less, preferably 1 mm or less on the surface of the wafer by vibration isolation of the irradiation light source. Of measuring flatness of untreated donor killer wafer. In the flatness measuring device of the donor killer unprocessed wafer that measures the flatness of the surface of the donor killer unprocessed wafer using the capacitance type flatness measuring device,
The capacitance flatness measuring instrument probe disposed on the surface of the rotating donor killer unprocessed wafer, and light having a wavelength that gives energy equal to or greater than the band gap at the upstream portion of the probe facing part. a light source for irradiating the web over wafer surface, away from and the measuring position to a front side of the rotational direction of the donor killer unprocessed wafer than the measurement position by the probe beyond the vibration width of the irradiation light in the wafer surface and a mounting support for supporting the light source so that light emitted from the light source is irradiated to a position, and a vibration isolating means interposed support portion mounting of this, on the wafer to be irradiated from the light source An apparatus for measuring the flatness of an untreated donor killer unprocessed wafer, characterized in that measurement can be performed while suppressing fluctuations in illuminance on the light-irradiated surface.   The light source mounting support part sandwiches the buffer plate with a fixed plate with respect to a fixed part such as a floor or a measuring instrument case, and stands up from one fixed plate to support the light source. 5. The flatness measurement apparatus for a donor killer unprocessed wafer according to claim 4, wherein vibration from the fixed part to the light source is prevented.

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