JP2011205084A - Device for detecting crack of wafer, method of detecting the crack, device and method for manufacturing solar cell or semiconductor element, and solar cell or semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting cracks, capable of reliably detecting the cracks of a wafer.SOLUTION: The device for detecting the cracks is configured such that a wafer 13 is positioned and held by being sandwiched between a pillar member 11 and an audio sensor 15 by interposing an elastic material; in this sandwiched state, a vibration part 19 coated with an elastic material 22 is made to collide with the wafer 13 and vibrated; vibration waveform transmitted to the wafer 13 then is detected by the audio sensor 15; and the cracks are detected based on a frequency component higher than the resonant frequency of the vibration waveform.

Description

  The present invention is, for example, a crack used to discriminate cracks such as cracks and internal cracks, which are called microcracks, in semiconductor wafers including silicon wafers and solar cell wafers, or compound semiconductor wafers such as SiC and GaN. The present invention relates to a detection device, a crack detection method thereof, a solar cell or semiconductor element manufacturing device, a manufacturing method thereof, and a solar cell or semiconductor element.

  Note that the semiconductor elements widely include discrete semiconductor elements, LEDs, CCDs, ICs, LSIs, and the like.

  For example, a single crystal solar cell uses a silicon wafer as a material. This silicon wafer is formed by cutting out a semiconductor ingot, generating a semiconductor, and forming a semiconductor wafer including a solar cell wafer. The solar cell wafer is then provided with electrodes to form solar cells, and a plurality of solar cells are arranged and connected to each other by wiring to produce a solar cell called a solar cell module. The

  Here, the solar battery includes both a solar battery cell and a solar battery module in which the solar battery cells are arranged. The silicon wafer, solar cell wafer, semiconductor wafer, or compound semiconductor wafer such as SiC or GaN is hereinafter collectively referred to as a wafer.

  Recently, especially in single crystal solar cells, wafers have been made thinner to reduce costs. In such a wafer, the frequency of occurrence of so-called cracks called micro cracks and internal cracks in the manufacturing process is increasing, and when this crack occurs, the conversion efficiency and durability of the solar cell to be manufactured are increased. This leads to a decrease in productivity, leading to a decrease in productivity. Further, not only in the solar cell wafer, a semiconductor is formed on the wafer in an intermediate process, and then a semiconductor element is manufactured through a final process. This causes not only a defect or a decrease in durability, but also a decrease in yield of semiconductor elements.

  Accordingly, various techniques have been proposed as inspection techniques for detecting the presence or absence of such cracks in the wafer.

  For example, as a first technique, there is a method of forcibly bending a silicon wafer and detecting and analyzing a shock wave generated at that time (see, for example, Patent Document 1).

  As a second technique, a substrate (wafer) is fixed using a vacuum suction pad, a sound is generated by applying vibration to the substrate, and the generated sound is captured by an acoustic sensor such as a non-contact microphone, There is a method of analyzing by the acoustic analysis (see, for example, Patent Document 2).

  Furthermore, as a third technique, there is a method of irradiating a wafer with infrared light and detecting and analyzing the transmitted light or reflected light using a CCD camera or the like (see, for example, Patent Document 3).

JP 2002-34392 A JP 2005-142495 A JP 2000-065760 A

  However, the first technique has a problem that cracks are generated due to the possibility of promoting the growth of cracks due to the configuration of bending the wafer.

  In the second technique, since the means for fixing the substrate and the acoustic sensor must be opposed to the wafer in a non-contact state, the structure of the sensor is complicated, and ambient noise is reduced. There is a problem that it is difficult to efficiently detect only the generated sound.

  Furthermore, in the third technique, irradiation with infrared light may cause the wafer to expand and cracks may temporarily stick together. It is difficult to identify cracks and it is difficult to make a reliable determination.

  The present invention has been made in view of the above circumstances, and has a simple configuration, realizes reliable and reliable crack detection, and can improve the productivity of solar cells or semiconductor elements. An object of the present invention is to provide a crack detection apparatus, a crack detection method thereof, a solar cell or semiconductor element manufacturing apparatus, a manufacturing method thereof, and a solar cell or semiconductor element.

  The invention according to claim 1 is directed to an acoustic sensor that is in contact with a wafer and detects a vibration waveform transmitted to the wafer, a wafer holding unit including the acoustic sensor, and an excitation unit for at least one surface of the wafer The wafer has cracks from the vibration waveform detected by the acoustic sensor in a state where the vibration means provided with the vibration means and the vibration part of the vibration means vibrates at least one surface of the wafer. A wafer crack detection device is configured to include signal processing means for extracting the indicated frequency and determination means for detecting the presence or absence of cracks in the wafer based on extraction information of the signal processing means.

  In this case, an elastic material can be interposed between at least one of the strut member and the wafer, between the acoustic sensor and the wafer, and between the excitation unit and the wafer.

  According to the above configuration, the wafer is sandwiched and held between the support member and the acoustic sensor with the elastic material interposed, and the vibration unit is vibrated with the elastic material interposed, High-precision detection can be performed without damaging the wafer and without being affected by air when the vibration waveform is detected by the acoustic sensor. As a result, after simplifying the configuration, high-accuracy crack detection is realized, and the yield of wafer manufacturing can be improved easily and easily.

  According to a second aspect of the present invention, the wafer holding means including the acoustic sensor is applied only to a surface of the wafer where the semiconductor is not formed and / or a portion where the semiconductor around the wafer is not formed normally. A wafer crack detection device was constructed so as to be in contact with each other.

  Also in this case, an elastic material can be interposed between at least one of the acoustic sensors and the wafer, and between the vibration unit and the wafer, but the elastic material may not be interposed.

  According to a thirteenth aspect of the present invention, there is provided a wafer crack detection method comprising: a wafer holding step for holding a wafer by a wafer holding means including an acoustic sensor; and an excitation for exciting at least one surface of the wafer by an excitation unit. A vibration waveform transmitted to the wafer by the acoustic sensor in a state in which vibration is applied to the wafer in the vibration step, and extracting a frequency indicating that the wafer has a crack from the vibration waveform; And a determination step for detecting the presence or absence of cracks in the wafer based on the extracted information.

  In this case, an elastic material can be interposed between at least one of the strut member and the wafer, between the acoustic sensor and the wafer, and between the excitation unit and the wafer.

  According to the above configuration, the wafer is held by the elastic material interposed between the support member and the acoustic sensor in the wafer holding step, and the vibration unit vibrates with the elastic material in the vibration step. As a result, the wafer can be detected with high accuracy without being affected by air when the vibration waveform is detected by the acoustic sensor in the determination step without damaging the wafer during vibration. As a result, after simplifying the configuration, high-accuracy crack detection is realized, and the yield of wafer manufacturing can be improved easily and easily.

  The wafer crack detection method according to the fourteenth aspect of the present invention is further characterized in that, in the wafer holding step, the wafer holding means including the acoustic sensor includes a surface on which a semiconductor of the wafer is not formed and / or a semiconductor around the wafer. Is configured to abut only on a portion that is not normally formed.

  Also in this case, an elastic material can be interposed between at least one of the acoustic sensors and the wafer, and between the vibration unit and the wafer, but the elastic material may not be interposed.

  The solar cell or semiconductor element manufacturing apparatus according to the invention of claim 25 is an apparatus for manufacturing a solar cell or a semiconductor element by generating a semiconductor on a wafer, and detecting cracks in the wafer of claim 1 and claim 2. It was configured including crack detection by the device.

  According to the above configuration, since a solar cell or a semiconductor element can be manufactured using a wafer having no cracks, it is possible to improve the manufacturing yield.

  A method for manufacturing a solar cell or a semiconductor device according to an invention according to claim 26 is a method for manufacturing a solar cell or a semiconductor device by generating a semiconductor on a wafer, and according to the method for detecting a crack in a wafer according to claims 13 and 14. It was configured including crack detection.

  According to the above configuration, since a solar cell or a semiconductor element can be manufactured using a wafer having no cracks, it is possible to improve the manufacturing yield.

  The invention according to claim 27 is a solar cell or a semiconductor element manufactured by producing a semiconductor on a wafer, and includes crack detection by the crack detection apparatus for a wafer according to claims 1 and 2 in the manufacturing process. Configured.

  According to the above configuration, since a solar cell or a semiconductor element can be manufactured using a wafer having no cracks, it is possible to improve the manufacturing yield.

  The invention according to claim 28 is a solar cell or a semiconductor device manufactured by producing a semiconductor on a wafer, and includes crack detection by the crack detection method for a wafer according to claims 13 and 14 in the manufacturing process. Configured.

  According to the above configuration, since a solar cell or a semiconductor element can be manufactured using a wafer having no cracks, it is possible to improve the manufacturing yield.

  As described above, according to the present invention, a crack detection of a wafer that realizes reliable and reliable crack detection with a simple configuration and can improve the productivity of solar cells or semiconductor elements. An apparatus, its crack detection method, a solar cell or semiconductor element manufacturing apparatus, its manufacturing method, and a solar cell or semiconductor element can be provided.

It is the perspective view which showed the structure of the crack detection apparatus of the wafer which concerns on one embodiment of this invention. It is the top view which showed the state which looked at FIG. 1 from one side. It is the top view which showed the state which looked at FIG. 1 from the side surface orthogonal to FIG. It is the side view which showed the holding | maintenance state of the wafer of FIG. It is the characteristic view shown in order to demonstrate an example without the crack in the determination step by the crack detection method of the wafer concerning one embodiment of this invention. It is the characteristic view shown in order to demonstrate an example with a crack in the determination step by the crack detection method of the wafer concerning one embodiment of this invention. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. It is a top view which shows roughly the structure of the wafer in which the semiconductor was formed. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on the other modification of embodiment shown in FIG. FIG. 13 is a side view showing a main part of a wafer crack detection apparatus according to still another modification of the embodiment shown in FIG. 12. It is the side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention. (A) And (b) is the top view and side view which showed the principal part of the crack detection apparatus of the wafer which concerns on other embodiment of this invention.

  Hereinafter, a wafer crack detection apparatus, a crack detection method thereof, a solar cell or semiconductor element manufacturing apparatus, a manufacturing method thereof, and a solar cell or semiconductor element according to embodiments of the present invention will be described in detail with reference to the drawings. To do.

  FIG. 1 shows a wafer crack detection apparatus according to an embodiment of the present invention. A support member 11 is erected on a base 10 at, for example, a substantially central portion (see FIGS. 2 and 3). . An elastic material 12 is attached to the support member 11 (see FIG. 4). On the elastic material 12, for example, one of the wafers 13 such as a solar cell wafer in which a semiconductor for a solar cell is generated. A surface is placed.

  On the base 10, a plurality of, for example, three positioning pins 14 constituting a wafer positioning means are erected around the support member 11 with a predetermined interval. The positioning pins 14 are in contact with three locations around the wafer 13 in a state in which the wafer 13 is placed on the support member 11 with the elastic material 12 interposed therebetween, thereby restricting movement of the wafer 13 in the surface direction. Then, the wafer 13 is positioned at the crack detection position.

  Further, a contact type acoustic sensor 15 is provided on the base 10 so as to face the support member 11. The acoustic sensor 15 has an elastic material 12 attached to the tip, and the elastic material is brought into close contact with the other surface of the wafer 13 placed on the elastic material 12 of the column member 11, thereby The wafer 13 is sandwiched and held in cooperation with the member 11 (see FIG. 4). A configuration is also possible in which the support member 11 pushes up the wafer 13 transferred onto the base 10 from below and holds it.

  The acoustic sensor 15 is detachably attached to, for example, the distal end portion of the support arm 17 constituting the support member, and is provided so as to be movable and adjustable in the vertical direction and the arrow A and B directions. The base end portion of the support arm 17 is provided so as to be movable in the directions of arrows C and D with respect to the base 10 via the moving mechanism 18. As a result, the acoustic sensor 15 is moved and adjusted so as to face the column member 11 of the base 10 via the support arm 17 and the moving mechanism 18.

  Here, the wafer 13 is sandwiched between the support member 11 and the acoustic sensor 15 in the state where the elastic material 12 is interposed, and crack detection is performed, thereby simplifying the support structure and manufacturing costs. Reduction can be achieved.

  Further, the base 10 has a vibrating means 19 that constitutes a vibrating means, for example, a bar-like vibrating portion 19 that can be dropped with respect to the support arm 20 that constitutes the support member, and moves in the directions of arrows A and B. Adjustable. The support arm 20 is provided so as to be movable and adjustable in the directions of arrows C and D with respect to the base 10 via the moving mechanism 21. As a result, the vibration exciter 19 is moved and adjusted with respect to the base 10 via the support arm 20 and the moving mechanism 21, and is moved and adjusted, for example, in the peripheral direction of the base 10 from the acoustic sensor 15.

  Recent solar cell wafers have many square shapes with rounded corners. In the present embodiment, as an example, the vibration unit 19 vibrates a point about 1/3 from the outside on the perpendicular line extending from the acoustic sensor 15 to the side of the square, and has obtained good results. .

  For example, an elastic material 22 including a material exhibiting viscoelasticity is attached to the tip portion of the vibration unit 19, and is temporarily lifted from the support arm 20 and dropped from a height of about 1 cm. Then, the vibration unit 19 collides with the surface of the wafer 13 from the elastic material 22 to vibrate the wafer 13.

  Here, the vibration unit 19 is preferably dropped on the wafer 13 closer to the end than the acoustic sensor 15 in order to vibrate the wafer 13 efficiently. In this way, the light vibration unit 19 of about 1 g with the elastic material 22 attached to the tip is dropped on the wafer 13 from a low height position of about 1 cm and vibrated, so that it is elastic at the time of collision. Since the stress due to the material 12 colliding with the wafer 13 can be kept small, the cracks and damage can be effectively prevented.

  As the above-described vibration means, the vibration unit 19 is installed on the lower surface of the wafer and is configured to be lifted by means such as a spring and collide with the lower surface of the wafer. It can be configured to drop on top, be launched obliquely and hit the wafer 13, or can be configured using a piezoelectric actuator, voice coil, ultrasonic transducer, or the like.

  The elastic materials 12 and 22 may be viscoelastic materials, for example, silicon rubber, other rubber materials or plastic materials, or formed by filling a bag or the like with a liquid or gel material. By interposing between the acoustic sensor 15, the support member 11, the excitation unit 19 and the wafer 13, the air between the acoustic sensor 15 and the support member 11 is prevented from intervening on the wafer 13. The two are placed in close contact with each other.

  That is, since the acoustic impedance differs greatly between the wafer 13 and the air, if air exists between the acoustic sensor 15 and the wafer 13, the acoustic signal generated on the wafer 13 is not efficiently transmitted to the acoustic sensor 15, and the measurement efficiency However, since the elastic material 12 is present between the acoustic sensor 15 and the wafer 13, air does not enter between the wafer 13 and is in direct contact with the wafer 13. As a result, mismatching of acoustic impedance can be suppressed, and high-sensitivity performance can be obtained by suppressing reflection, and desired noise resistance can be obtained without being affected by ambient noise, and vibration can be prevented. It can be efficiently converted into a voltage signal.

  In addition, since the wafer 13 is sandwiched and held between the support member 11 and the acoustic sensor 15 with the elastic material 12 interposed as shown in FIG. 4, vibration can be efficiently converted into an electrical signal as described above. The force for sandwiching the wafer 13 can be made relatively weak. As a result, the stress applied to the wafer 13 during crack detection can be kept small, and highly reliable crack detection can be performed. The elastic material 12 interposed between the column member 11 and the acoustic sensor 15 and the wafer 13 is provided by being attached to each end of the column member 11 and the acoustic sensor 15, for example.

  And, when the elastic material 22 provided in the vibration unit 19 is dropped on the surface of the wafer 13 and collides, the material prevents the generation of harmonic components and increases the measurement accuracy by the acoustic sensor 15; It plays the role of preventing damage to the wafer 13 at the time of collision.

  Here, as the acoustic sensor 15, for example, an AE sensor (an ultrasonic sensor using a piezoelectric element) is used, and in addition, an electrodynamic type, an electrostatic type, a piezoelectric type, and a strain gauge that can be contacted with the elastic material 12 interposed. Etc. are effective. As a result, the acoustic sensor 15 is in close contact with the wafer 13 via the elastic material 12, and air is not present between them, so that high-sensitivity performance is ensured as described above, and the desired noise resistance is achieved. As a result, it is less affected by ambient noise, and highly accurate measurement is realized. Furthermore, if the resonance frequency of the acoustic sensor is close to the frequency region indicating the presence of cracks, a result with higher sensitivity and excellent noise resistance can be obtained.

  The output of the acoustic sensor 15 is connected to the signal processing unit 24 constituting the signal processing means, for example, via the amplification unit 23, and the vibration unit 19 is dropped on the wafer 13 to give an impact. The voltage signal 1 based on the vibration waveform transmitted to the wafer 13 is output to the amplifying unit 23. The amplifying unit 23 amplifies the input voltage signal 1 to generate a voltage signal 2 and outputs the voltage signal 2 to the signal processing unit 24.

  The signal processing unit 24 sets a cutoff frequency using, for example, a high-pass filter or a band-pass filter according to the performance of the acoustic sensor 15 and the type of the wafer 13. That is, the wafer 13 generates only a low frequency (mainly audible frequency) such as a resonance frequency due to resonance, but if a crack is present, a frequency higher than the resonance frequency (mainly ultrasonic waves) is generated. It has been known. Therefore, the signal processing unit 24 sets the cutoff frequency of the high-pass filter to a frequency (mainly ultrasonic) higher than the resonance frequency of the wafer, for example, about 1 kHz to 10 MHz. Alternatively, it is possible to extract a frequency component characteristically generated by a crack of the wafer by a band pass filter.

  The signal processing unit 24 outputs the voltage signal 3 obtained by extracting a frequency higher than the resonance frequency from the input voltage signal 2 to the determination unit 25 constituting the determination unit. The determination unit 25 counts the number of points exceeding a predetermined voltage threshold, for example, voltage ± 10 in FIGS. 5 and 6 within a predetermined time of the time domain waveform of the input voltage signal 3, and the number of points is It is determined whether it has exceeded a preset threshold, for example, 20 times or more, and if it does not exceed the threshold as shown in FIG. 5, it is determined that there is no crack, and if it exceeds the threshold as shown in FIG. Is determined.

  As the wafer 13 used for the crack detection, it is effective for any of silicon wafers, solar cell wafers in which semiconductors constituting the solar cell are generated, semiconductor wafers in which semiconductors are generated, or compound semiconductor wafers such as SiC and GaN. It is.

  Next, the crack detection procedure for the wafer 13 will be described.

  First, in the wafer holding step, the wafer 13 is placed on the elastic material 12 of the support member 11, and its periphery is brought into contact with a plurality of positioning pins 14, and the acoustic sensor 15 is moved by the moving mechanism 28 and the support arm 17. It is operated so as to face the column member 11 and is brought into contact with the upper surface of the wafer 13 through the elastic material 12 so as to be in close contact therewith. Here, the acoustic sensor 15 and the support member 11 are arranged to face each other in a state where the elastic material 12 is interposed and air is prevented from entering between both surfaces of the wafer 13 so as to position and hold the wafer 13.

  In the vibration step, the vibration unit 19 is opposed to the end side of the acoustic sensor 15 on the wafer 13 as described above. The vibration unit 19 is lifted to a predetermined height as described above, and the wafer is 13 is dropped onto the elastic member 22 and collided from the elastic material 22 at the tip thereof to be vibrated. With the wafer 13 being vibrated, the process proceeds to a determination step.

  In this determination step, the voltage signal 1 based on the vibration waveform transmitted to the wafer 13 by the acoustic sensor 15 is detected and output to the amplifying unit 23. The voltage signal 1 input by the amplifying unit 23 is amplified to generate the voltage signal 2. The voltage signal 2 is input to the signal processing unit 24. The signal processing unit 24 extracts the voltage signal 3 having a frequency higher than the resonance frequency of the wafer 13 from the input voltage signal 2 and outputs the voltage signal 3 to the determination unit 25. As described above, the determination unit 25 detects the presence or absence of a crack in the wafer 13 based on the input voltage signal 3, and determines whether the wafer 13 is good or bad according to the presence or absence of the crack.

  In the wafer 13 on which crack detection has been performed using the above-described wafer crack detection apparatus, a semiconductor is generated, wiring, packaging, and the like are performed, and a solar cell or a semiconductor element is formed. Thereby, since it becomes possible to manufacture a solar cell or a semiconductor element only using the favorable wafer 13, the yield of the manufactured solar cell or semiconductor element can be improved.

  In addition, the wafer 13 on which crack detection has been performed by the above-described wafer crack detection method, after a semiconductor is generated, is subjected to wiring, packaging, and the like to form a solar cell or a semiconductor element. Thereby, since it becomes possible to manufacture a solar cell or a semiconductor element only using the favorable wafer 13, the yield of the manufactured solar cell or semiconductor element can be improved.

  In addition, the wafer 13 on which crack detection has been performed by the above-described wafer crack detection apparatus is generated by using a solar cell or a semiconductor element manufacturing apparatus, and then subjected to wiring, packaging, etc., and the solar cell or semiconductor element. Is manufactured. Thereby, since it becomes possible to manufacture a solar cell or a semiconductor element only using the favorable wafer 13, the improvement in the yield in manufacture of a solar cell or a semiconductor element can be aimed at.

  The wafer 13 on which crack detection has been performed by the above-described method for detecting cracks in a wafer is subjected to wiring, packaging, etc. after a semiconductor is produced using a solar cell or a semiconductor element manufacturing method, and the solar cell. Alternatively, a semiconductor element is manufactured. Thereby, since it becomes possible to manufacture a solar cell or a semiconductor element only using the favorable wafer 13, the improvement in the yield in manufacture of a solar cell or a semiconductor element can be aimed at.

  In the above-described embodiment, the case where the amplification unit 23 is configured separately from the signal processing unit 24 has been described. However, the present invention is not limited to this, and the output of the acoustic sensor 15 is necessary for signal processing. If the signal processing unit 24 has a desired output voltage, or the signal processing unit 24 is configured to have an amplification function, the amplifier 23 can be configured without being provided separately. Be expected.

  In the above-described embodiment, the case where the quality of the wafer 13 is determined based on the number of times that exceeds the voltage threshold using the voltage signal has been described. However, the present invention is not limited to this. It is also possible to perform the analysis and determine whether the wafer 13 is good or bad based on the frequency component.

  Then, in addition to the number of times exceeding the voltage threshold, average value detection or effective value detection is performed, and smoothing is performed with a predetermined time constant, or a result such as peak hold is used to determine pass / fail, or It is also possible to make a configuration such that a defect is determined in a state where these integral values are a certain value or more.

  Further, the present invention is not limited to the above-described embodiment. For example, as shown in FIG. 7, a pair of acoustic sensors 151, 151 are arranged opposite to each other as shown in FIG. 7, and the wafer 13 is mounted by the pair of acoustic sensors 151, 151. It is also possible to configure so as to detect cracks by sandwiching and holding. However, in the description of FIG. 7, for the sake of convenience, the same portions as those in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, in this embodiment, one of the pair of acoustic sensors 151 and 151 is provided so as to stand on the base 10 with the tip end portion to which the elastic material 12 is attached facing up. The other of the acoustic sensors 151 and 151 corresponds to the other through the support arm 14 with the elastic material 12 attached to the tip portion similarly arranged oppositely and with the elastic material 12 facing downward. And can be moved freely.

  The acoustic sensors 151 and 151 are configured such that one surface of the wafer 13 is placed on one elastic material 12 and the other of the acoustic sensors 151 and 151 is moved and adjusted with respect to the other surface of the wafer 13. When the elastic material 12 is brought into close contact with each other, the wafer 13 is sandwiched and held by both. In this state, the wafer 13 is vibrated using the vibration unit 19 as described above. For example, the voltage signal based on the vibration waveform transmitted to the wafer 13 is measured by both acoustic sensors 151 and 151, and crack detection is performed in the same manner. Is done.

  In this embodiment, for example, even if one of the acoustic sensors 151 and 151 is difficult to measure the voltage signal, it is possible to determine the defect of the wafer 13, and the detection can be diversified, which is further improved. Expected. Alternatively, the determination reliability can be improved by performing determination based on one or both of the outputs of the acoustic sensors 151 and 151.

  Further, according to the present invention, as shown in FIG. 8, an acoustic sensor 152 to which the elastic material 12 is attached is provided so as to stand on the base 10, and the central portion of the wafer 13 is located at the acoustic sensor 152 using the vacuum suction pad 26. The wafer 13 may be positioned and held by being transported so as to be positioned and bringing the vacuum suction pad 26 and the acoustic sensor 152 into contact with each other. Here, the elastic material 12 is also provided at the portion of the vacuum suction pad 26 in contact with the wafer 13, and the same effect as in the other embodiments is achieved.

  In particular, in the case of a wafer on which a semiconductor is formed, it is preferable that the semiconductor wafer is held and vibrated as in still another embodiment described below.

  The wafer 13 has a semiconductor formed on its surface side by a fine process. Therefore, on the surface side 13A of such a wafer 13, a semiconductor as shown by oblique lines in FIG. 9 is formed, and the semiconductor forming region 13-1 susceptible to damage and the surrounding semiconductor surrounding the semiconductor forming region 13-1 are formed. It is manufactured to have a peripheral region 13-2 that is not normally formed. In the semiconductor formation region 13-1 on the surface 13A side, it is not preferable that the support member 11, the acoustic sensor 15 or the vibration exciter 19 are in contact with each other even though the elastic materials 12 and 22 are used. On the surface side of 13, it is preferable that the strut member 11, the acoustic sensor 15, or the vibration unit 19 is disposed so that only the peripheral region 13-2 is in contact with the elastic materials 12 and 22. Further, since the back surface 13B side of the wafer 13 is only a semiconductor substrate or a layer structure is formed on the semiconductor substrate, there is no risk of damage, and the back surface 13B side is a support column instead of the front surface 13A side. The member 11, the acoustic sensor 15, or the vibration unit 19 may be brought into contact via the elastic materials 12 and 22. Further, the side end surface of the wafer 13 is also a region connected to the peripheral region 13-2, and the support member 11 or the acoustic sensor 15 may be similarly held through the elastic materials 12 and 22 and held.

  Various embodiments based on the structural characteristics of the wafer 13 will be described below with reference to FIGS. 10 to 16A and 16B. Here, the elastic materials 12 and 22, the support member 11, the acoustic sensor 15 or the vibration unit 19 shown in FIGS. 10 to 16A and 16B are provided in the wafer crack detection apparatus shown in FIG. Therefore, for details of the apparatus, refer to the above-described embodiment. In the following embodiments and FIGS. 10 to 16A and 16B, the same reference numerals are used as in the above-described embodiments, and detailed descriptions thereof are omitted. Regarding the above, reference is also made to the embodiment already described.

  In the embodiment shown in FIG. 10, the wafer 13 is placed on the acoustic sensor 15 so that the back surface 13B side thereof contacts the acoustic sensor 15 via the elastic material 12, and the peripheral region 13 on the front surface 13A side. -2 is brought into contact with the support member 11 via the elastic material 12, and an appropriate support pressure is applied to the wafer 13 so that the wafer 13 is supported so as not to move. Then, an excitation pressure is applied to the wafer 13 upwardly as indicated by an arrow from an excitation unit 19 (not shown) arranged on the back surface 13B side, so that the wafer 13 is vibrated. . The presence or absence of cracks in the wafer 13 is detected by the vibration of the wafer 13 as described above.

  In the support structure shown in FIG. 10, it is preferable that the support pressure applied from the support member 11 to the wafer 13 is adjusted to an optimum support pressure so as not to expand cracks generated in the wafer 13 itself. Further, since the vibration unit 19 vibrates from the back surface 13B side of the wafer 13, it is not possible to employ vibration due to the drop of the vibration unit 19, and the vibration unit 19 collides with a means such as a spring. It can be configured by an electromechanical vibration element such as a piezoelectric actuator or the like described above. Furthermore, in the support structure in FIG. 10, when the acoustic sensor 15 can support the wafer 13 only by its own weight and the vibration does not cause the wafer 13 to move, the support member 11 is provided. Not necessary. In this structure, the wafer 13 may fall off the acoustic sensor 15 due to vibration from the outside, so that the positioning pins 14 shown in FIG. 1 are provided to prevent the wafer 13 from moving on the acoustic sensor 15. It is preferable. Further, a non-contact stopper may be provided on the side surface or the back surface of the wafer 13 in order to prevent the wafer 13 from being displaced or inclined together with or in place of the positioning pin 14.

  In the holding vibration structure shown in FIG. 10, the acoustic sensor 15 is disposed in the central region on the back surface 13 </ b> B side of the wafer 13, but as shown in FIG. 11, the acoustic sensor 15 is opposed to the column member 11. May be arranged. In the holding vibration structure in FIG. 11, as an example, a wafer 13 is placed on three acoustic sensors 15 via an elastic material 12, and the column member 11 is elastic so as to face the end surfaces of the three acoustic sensors 15. The acoustic sensor 15 and the column member 11 are arranged so as to be in contact with the wafer 13 through the material 12 and to support the wafer 13 at three points. Also in this arrangement structure, the holding force (supporting force) applied to the wafer 13 is preferably adjusted so as not to expand cracks generated in the wafer 13 even during vibration. From this viewpoint, it is preferable that the end surfaces on which the acoustic sensor 15 and the column member 11 support the wafer 13 are formed to have substantially the same shape and the same area.

  In the holding vibration structure shown in FIG. 11, the wafer 13 is placed on the plurality of acoustic sensors 15. However, the mounting is substantially the same type as the acoustic sensor 15 that replaces at least one acoustic sensor 15 and the acoustic sensor 15. A mounting support (not shown) is disposed below the wafer 13, and the wafer 13 is placed on the at least one acoustic sensor 15 and the mounting support (not shown) via the elastic material 12. May be. It is preferable that the acoustic sensor 15 is optimally arranged at the optimum position for detecting cracks in the wafer 13. Further, in the holding vibration structure shown in FIG. 11, the presence or absence of cracks in the wafer 13 is detected in the same manner as described above by vibrating the wafer 13 from below the wafer 13. Further, also in the support structure in FIG. 11, when the acoustic sensor 15 can support the wafer 13 only by its own weight and the vibration does not cause the movement of the wafer 13, the support member on the surface 13 </ b> A side. 11 may not be provided. In this structure, since the wafer 13 may fall off the acoustic sensor 15 due to external vibration, the positioning pin 14 shown in FIG. 1 is similarly provided, and the movement of the wafer 13 on the acoustic sensor 15 is performed. It is preferably prevented. Further, a non-contact stopper may be similarly provided on the side surface or the back surface of the wafer 13 in order to prevent the wafer 13 from being displaced or inclined together with or in place of the positioning pin 14.

  10 and 11, the support member 11 that holds (supports) the wafer 13 is brought into contact with the peripheral region 13-2 on the wafer surface 13A side through the elastic material 12, and the acoustic sensor 15 is provided around the wafer back surface 13B. Although arranged in the region, as shown in FIG. 12, the side end surface 13 </ b> C of the wafer 13 may be pressed against the opposing acoustic sensor 15 via the elastic material 12 and supported between the opposing acoustic sensors 15. In the press-contact support structure shown in FIG. 12, instead of supporting the wafer 13 with the opposing acoustic sensor 15, for example, the three acoustic sensors 15 hold the elastic material 12 at three points around the side end surface 13 </ b> C of the wafer 13. The wafer 13 may be supported by pressure contact.

  In the holding structure (support structure) in FIG. 12, the end of the acoustic sensor 15 is formed flat, and the wafer 13 is pressed and supported by the flat elastic material 12 provided on the flat portion. As shown in FIG. 12, the end of the acoustic sensor 15 is formed in a recess capable of receiving the side end of the wafer 13, and the elastic layer of the elastic material 12 provided in the recess can support the wafer 13 in pressure contact as in FIG. good. Further, as shown in FIG. 14, the acoustic sensor 15 has an end portion formed on a step portion so that the periphery and the side end of the back surface 13B of the wafer 13 can be contacted and supported. The acoustic sensor 15 may press and support the wafer 13 in the same manner as in FIG. 12 by an L-shaped elastic layer of the elastic material 12 provided inside.

  In the description of the holding structure (supporting structure) shown in FIGS. 12 to 14, the explanation about the vibration is omitted, but if it is vibrated from below as already explained with reference to FIG. 10, it has already been explained. Similarly, acoustic vibration is detected by the acoustic sensor 15 and the presence or absence of cracks in the wafer 13 is detected.

  In the holding structure (support structure) shown in FIGS. 12 to 14, the wafer 13 is held by at least one acoustic sensor 15 and the support portion 11 in place of the acoustic sensor 15, and the acoustic vibration is detected by one acoustic sensor 15. Then, the presence or absence of cracks in the wafer 13 may be detected. Here, in the wafer 13 having a disc shape as shown in FIG. 9 and having a cutout portion 13D partially cut out linearly, at least one linear end portion of the cutout portion 13D is provided. The acoustic sensor 15 is preferably contacted for acoustic vibration detection. Further, in the holding structure (support structure) shown in FIGS. 12 to 14, the wafer 13 is held by the support portion 11 in place of all the acoustic sensors 15, and the acoustic sensor 15 for separately detecting the vibration of the wafer 13 is shown in FIG. Alternatively, the presence or absence of cracks in the wafer 13 may be detected by detecting acoustic vibration by the acoustic sensor 15 that is arranged in the same manner as in FIG.

  10 to 14, it is assumed that the surface 13A side of the wafer 13 is directed upward, but the back surface 13B side of the wafer 13 is directed upward to form a circuit element. The surface 13A side of the wafer 13 may be directed downward. Then, the wafer 13 may be vibrated by the vibration unit 19 from the back surface 13B side (the upper side of the wafer 13) of the wafer 13 and the acoustic vibration may be detected from the acoustic sensor 15 provided at the side edge of the wafer 13. .

  Further, as shown in FIG. 15, the side edge of the wafer 13 is supported at three points by three support members 41 as an example, and the wafer 13 is vibrated from the back surface 13B side (the upper side of the wafer 13) of the wafer 13. The acoustic vibration may be detected. When the wafer 13 is vibrated from the back surface 13B side (the upper side of the wafer 13) of the wafer 13, the vibration unit 19 is dropped to vibrate the wafer 13 as described with reference to FIG. be able to.

  As another embodiment, as shown in FIGS. 16A and 16B, a support material 31 may be added to the upper portion of the acoustic sensor 15, and the wafer 13 may be placed on the support material 31. In the holding structure shown in FIG. 16, the support member 31 has a ring-shaped holding contact portion 31 </ b> A as an example, and this ring-shaped holding contact portion 31 </ b> A is supported by the support column portion 31 </ b> B and fixed to the upper portion of the acoustic sensor 15. ing. The wafer 13 is vibrated from the back surface 13B side of the wafer 13 with the back surface 13B of the wafer 13 in contact with the holding contact portion 31A. It is preferable that the excitation pressure is adjusted so that the wafer 13 does not move from above the holding contact portion 31 </ b> A, and the excitation pressure is applied to the wafer 13 from the excitation portion 19 (not shown). The acoustic vibration generated in the wafer 13 by this vibration is transmitted to the acoustic sensor 15 via the support member 31, and the acoustic vibration is detected by the acoustic sensor 15. The holding contact portion 31A of the support member 31 shown in FIGS. 16A and 16B is not limited to a ring shape, and may have another shape, for example, a rectangular shape or a concave shape. 31 A of contact parts are not provided, but the extended end of the some support material 31 may be formed in a free end, and the wafer 13 may be mounted on this some free end. When the support material 11 is thin, the wafer 13 can be supported by the free ends of the three support materials 31 by preparing at least three support materials 31. The support material 31 is not limited to three for supporting the wafer 13 at three points, and can support the wafer 13 stably as long as it is three or more.

  In the description of FIGS. 1 to 16, the example in which the elastic materials 12 and 22 are provided between the support member 11 or the acoustic sensor 15 and the wafer 13 has been described. However, the back surface 13B side of the wafer 13 or the peripheral region 13-2 portion. The elastic materials 12 and 22 may be omitted if there is no problem even if some scratches are generated. If the acoustic sensor 15 and the wafer 13 are both sufficiently flat and are in close contact with each other with almost no air layer, the acoustic signal generated on the wafer 13 is transmitted to the acoustic sensor 15 with sufficient efficiency. Therefore, vibration can be efficiently converted into a voltage signal.

  Therefore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the effect of the invention can be obtained. In such a case, a configuration in which this configuration requirement is deleted can be extracted as an invention.

  DESCRIPTION OF SYMBOLS 10 ... Base, 11 ... Supporting member, 12, 22 ... Elastic material, 13 ... Wafer, 14 ... Positioning pin, 15, 151, 152 ... Acoustic sensor, 17 ... Support arm, 18 ... Moving mechanism, 19 ... Excitation part, DESCRIPTION OF SYMBOLS 20 ... Support arm, 21 ... Moving mechanism, 23 ... Amplifying part, 24 ... Signal processing part, 25 ... Determination part, 26 ... Vacuum suction pad.

Claims (28)

An acoustic sensor that is in contact with the wafer and detects a vibration waveform transmitted to the wafer;
Wafer holding means including the acoustic sensor;
A vibration means provided with a vibration unit for at least one surface of the wafer;
Signal processing means for extracting a frequency indicating that the wafer has a crack from a vibration waveform detected by the acoustic sensor in a state where the vibration unit of the vibration means vibrates at least one surface of the wafer; ,
Determination means for detecting the presence or absence of cracks in the wafer based on the extraction information of the signal processing means;
A crack detection apparatus for a wafer, comprising:   2. The wafer holding means including the acoustic sensor abuts only on a surface of the wafer where the semiconductor is not formed and / or a portion where the semiconductor around the wafer is not formed normally. The crack detection apparatus of the wafer as described.   3. The crack detection of a wafer according to claim 1, wherein an elastic material is interposed between at least one of the wafer holding means including the acoustic sensor and the wafer, and between the excitation unit and the wafer. apparatus.   3. The wafer crack detection device according to claim 1, further comprising wafer positioning means for positioning in contact with the periphery of the wafer at a crack determination position of the wafer.   3. The wafer crack detection apparatus according to claim 1, wherein at least a part of the wafer holding means including the acoustic sensor is provided so as to be movable up and down with respect to at least one surface of the wafer.   6. The wafer crack detection device according to claim 1, wherein the vibration means is provided so as to be movable and adjustable in a direction orthogonal to a vibration direction of the vibration unit.   7. The wafer crack detection apparatus according to claim 1, wherein the wafer holding means including the acoustic sensor is disposed at a central portion of the wafer.   8. The wafer according to claim 7, wherein the vibration unit of the vibration unit vibrates an end side of at least one surface of the wafer with respect to a contact position of the wafer holding unit including the acoustic sensor. Crack detection device.   9. The wafer crack detection apparatus according to claim 1, wherein the elastic material is silicon rubber.   10. The wafer crack detection apparatus according to claim 1, wherein the acoustic sensor is an AE sensor.   11. The wafer crack detection apparatus according to claim 10, wherein the AE sensor has a resonance frequency set corresponding to a frequency indicating a crack.   12. The wafer crack detection apparatus according to claim 1, wherein the determination means determines the number of times that the time waveform exceeds a threshold value within a predetermined time. A wafer holding step of holding the wafer by a wafer holding means including an acoustic sensor;
An excitation step of exciting the at least one surface of the wafer by an excitation unit;
In this vibration step, with the vibration applied to the wafer, the acoustic sensor detects a vibration waveform transmitted to the wafer, extracts a frequency indicating that the wafer has a crack from the vibration waveform, and extracts the information. A determination step for detecting the presence or absence of cracks in the wafer based on:
A method for detecting cracks in a wafer, comprising:   In the wafer holding step, the wafer holding means including the acoustic sensor contacts only a surface of the wafer where the semiconductor is not formed and / or a portion where the semiconductor around the wafer is not formed normally. A method for detecting cracks in a wafer according to claim 13.   The crack detection of a wafer according to claim 13 or 14, wherein an elastic material is interposed between at least one of the wafer holding means including the acoustic sensor and the wafer, and between the excitation unit and the wafer. Method.   15. The method for detecting cracks in a wafer according to claim 13, wherein in the wafer holding step, a surface direction of the wafer is positioned at a holding position.   15. The wafer according to claim 13, wherein in the wafer holding step, at least a part of the wafer holding means including the acoustic sensor is moved up and down relative to at least one surface of the wafer. Crack detection method.   18. The wafer crack detection method according to claim 13, wherein in the vibration step, the vibration part is moved and adjusted in a direction orthogonal to the vibration direction.   19. The wafer crack detection method according to claim 13, wherein the measurement position of the acoustic sensor is a central portion of the wafer.   20. The method for detecting a crack in a wafer according to claim 19, wherein the vibration position in the vibration step is on an end side of the contact position of the acoustic sensor on at least one surface of the wafer.   21. The method for detecting cracks in a wafer according to claim 13, wherein the elastic material is silicon rubber.   22. The method for detecting cracks in a wafer according to claim 13, wherein the acoustic sensor is an AE sensor.   23. The wafer crack detection method according to claim 22, wherein the AE sensor has a resonance frequency set corresponding to a frequency indicating a crack.   24. The method for detecting cracks in a wafer according to any one of claims 13 to 23, wherein in the determination step, the determination is made by the number of times that the time waveform exceeds a threshold value within a predetermined time.   An apparatus for producing a solar cell or a semiconductor element by producing a semiconductor on a wafer, comprising the detection of a crack by the crack detection apparatus for a wafer according to claim 1 to 12, wherein the apparatus for producing a solar cell or a semiconductor element is provided. .   A method for producing a solar cell or a semiconductor element by producing a semiconductor on a wafer, comprising the detection of a crack by the crack detection method for a wafer according to any one of claims 13 to 24. .   A solar cell or a semiconductor element manufactured by producing a semiconductor on a wafer, wherein the crack detection by the wafer crack detection device according to claim 1 is performed during a manufacturing process. element.   25. A solar cell or a semiconductor element manufactured by producing a semiconductor on a wafer, wherein the crack detection by the method for detecting a crack of a wafer according to claim 13 to 24 is performed during the manufacturing process. element.

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