JP2005268823A - Defect inspection method and its unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a real time inspection to check foreign matters of a wafer in the middle of transport concerning the inspection method for foreign matters of the wafer, and to prevent a large quantity of failures in the volume production line of a semiconductor production process before it happens, thereby maintaining the same yield level. <P>SOLUTION: In the volume production line of a semiconductor production process, the physical size of a foreign matter inspection unit is reduced and the unit is located in the transport system between the input/output ports or processing units of the semiconductor production line. Also, a unit is provided to repeatedly detect foreign matters on the pattern parts on a wafer 111 by means of a lens array 153 of a refractive index variation type, spatial filter 154, and pattern information removal circuit, which makes it possible to inspect foreign matters on the wafer 111 in the middle of transport. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention detects a foreign matter generated in a mass production line of a semiconductor manufacturing process and detects a foreign matter generated in a mass production line, analyzes and measures the foreign matter occurrence state in a semiconductor manufacturing process, and inspects the foreign matter on a semiconductor substrate. The present invention relates to a foreign substance inspection apparatus.

  In the conventional semiconductor manufacturing process, if foreign matter exists on the semiconductor substrate (wafer), it may cause defects such as wiring insulation failure or short circuit, and when the semiconductor element is miniaturized and minute foreign matter exists in the semiconductor substrate, The foreign matter may cause damage to the capacitor insulating film and gate oxide film. These foreign substances are caused by various causes such as those generated from the operating part of the transfer device, those generated from the human body, those generated by reaction in the processing apparatus by the process gas, and those mixed in chemicals or materials. Are mixed in various states.

As one of the conventional techniques for detecting foreign matter on this type of semiconductor substrate, as described in Japanese Patent Application Laid-Open No. 62-89336 (Patent Document 1), a semiconductor is irradiated with a laser to irradiate a semiconductor. By detecting scattered light from foreign matter generated when foreign matter is attached to the substrate and comparing it with the inspection result of the same type semiconductor substrate inspected immediately before, there is no false information due to the pattern, and high sensitivity and high reliability As for what makes a foreign matter inspection possible, as disclosed in Japanese Patent Application Laid-Open No. 63-135848 (Patent Document 2), the semiconductor substrate is irradiated with a laser so that the foreign matter adheres to the semiconductor substrate. In some cases, scattered light from a foreign material generated in the case of detection is detected, and the detected foreign material is analyzed by an analysis technique such as laser photoluminescence or secondary X-ray analysis (XMR).
JP-A-62-89336 JP-A 63-135848

  The above-mentioned conventional technology does not distinguish between the mass production line and the mass production line in the semiconductor manufacturing process, and the inspection equipment used in the mass production line is applied to the mass production line as it is. However, the conventional inspection apparatus is a stand-alone type, and a semiconductor substrate processed on the production line is brought into the inspection apparatus to inspect foreign matter. Therefore, since it takes time to transport the semiconductor substrate and to inspect the foreign matter, it is difficult to increase the frequency of the inspection to a sufficient value.

  This is because the conventional apparatus has a large scale and takes a long inspection time, and in order to realize a real-time monitor using these conventional apparatuses, it is necessary to arrange a large number of apparatuses, which is practically difficult. there were. In reality, it has been a limit to inspect one semiconductor substrate every one lot, several lots or every day. In such a foreign matter inspection, it cannot be said that the occurrence of foreign matter is detected sufficiently early. In other words, it was far from ideal real-time sampling for mass production lines. Furthermore, in order to reduce the number of processes and equipment of the mass production line, there is a problem that necessary and sufficient monitors need to be installed at necessary and sufficient locations.

  One of the major tasks in the start-up of mass production of LSI is to investigate the cause of these foreign substances and take countermeasures. The cause of this is the detection of the generated foreign substances and analysis of the element type, etc. It becomes a big clue of search. On the other hand, in the mass production line, it is necessary to quickly detect the occurrence of these foreign substances and take countermeasures. When time elapses from the generation of a foreign object to the detection of the generation of a foreign object, the number of occurrences of defects increases and the yield decreases. Therefore, in order to maintain a high yield, it is indispensable to shorten the elapsed time from the occurrence of a foreign object to its detection. In other words, in order to maximize the effect of foreign matter inspection, it is necessary to shorten the sampling time of the monitor, and ideally, real-time sampling is desirable for the mass production line.

  An object of the present invention is to provide a mass production line that is installed at an inlet of a processing apparatus, an outlet of the processing apparatus, or a transfer system between a plurality of processing apparatuses, and can detect the occurrence of foreign matter on a semiconductor substrate in real time. An object of the present invention is to provide a foreign matter occurrence state analysis method and apparatus in a semiconductor manufacturing process.

The foreign matter inspection apparatus in the mass production line of the present invention realizes the above-described real-time sampling, reduces the size of the foreign matter monitoring apparatus, and is placed in the input / output port of the processing apparatus of the semiconductor manufacturing line or in the transport system between the processing apparatuses. Configured to be possible. That is, the present invention relates to an imaging optical system composed of an oblique illumination system composed of an illumination array and a lens array or a microlens group in a mass production semiconductor manufacturing line equipped with a plurality of processing apparatuses, and a flow of the imaging optical system. A foreign matter monitoring device that includes a spatial filter disposed on a surface conversion surface and a detector disposed at an imaging position of the imaging optical system to detect the occurrence of foreign matter on a semiconductor substrate. An apparatus for analyzing the occurrence of foreign matter in a semiconductor manufacturing process, wherein the apparatus is installed in an entrance, an outlet, or a transfer system between a plurality of processing apparatuses to detect the state of occurrence of foreign substances on a semiconductor substrate by the processing apparatus. is there.

  According to another aspect of the present invention, there is provided an apparatus for inspecting a foreign substance on a semiconductor substrate. The illumination system illuminates the semiconductor substrate in a linear shape with a plane wave at a substantially short wavelength, and the semiconductor substrate illuminated by the illumination system. An imaging optical system for forming a reflected light image, a spatial filter installed so as to shield diffracted light from a repetitive pattern on a semiconductor substrate in the middle of the imaging optical system, and an optical image formed Detecting detector, erasing means for erasing signals repeatedly generated on the semiconductor substrate among signals detected by the detector, and detecting foreign matter on the semiconductor substrate based on the signals not erased by the erasing means A foreign matter inspection apparatus comprising: Further, the present invention is characterized in that, in the foreign matter inspection apparatus, the imaging optical system is constituted by a refractive index change type lens array.

  At the start of mass production of semiconductor manufacturing processes, each process, equipment, etc. is evaluated using expensive and high-performance evaluation equipment to evaluate and improve (debug) materials, processes, equipment, and designs. Reduce the number and facilities as much as possible, especially reduce the number of inspection and evaluation items to reduce the cost of equipment and the time required for inspection and evaluation. For this purpose, the foreign matter detection and analysis system that devised the sampling semiconductor substrate was used to investigate the cause of foreign matters so that the evaluation at the time of mass production start-up can proceed smoothly and quickly. Measures are taken for dust sources, and the results are fed back to each material, process, equipment, etc., and the specifications of processes that are prone to dusting are made into design specifications for elements that are resistant to dusting. A foreign substance monitor on a semiconductor substrate is installed as needed in a place where foreign substances are likely to be used for making evaluation specifications, or a specification for monitoring only the increase or decrease of specific foreign substances at a specific place.

  By separating the mass production line from the mass production line as described above, foreign matter detection, analysis, and evaluation equipment can be efficiently operated at the time of mass production lineup, enabling rapid start-up of the mass production line. The mass production line can be reduced in weight by making the foreign matter inspection and evaluation equipment used as simple as possible.

  Further, in the monitoring device for the mass production line of the present invention, attention was paid to the following method in order to solve the inspection device having the same function as a conventional large-sized device at high speed and small size. First, we focused on the repeatability of the memory. Conventionally, a method for removing a repeated pattern and detecting a defect is known. This method can reliably ensure detection performance. However, it is not mentioned that this method is advantageous in realizing the above monitoring device. Furthermore, the monitor in this case does not need to monitor every point on the semiconductor substrate, and only needs to monitor the semiconductor substrate at a specific ratio. We paid attention to the fact that just monitoring only the effect.

  In a repetitive pattern, light is emitted only in a specific direction when it is irradiated with coherent light. That is, in the case of a memory, light emitted from a repetitive portion in a specific direction can be shielded by a spatial filter, and foreign matter that does not occur repeatedly can be detected with high sensitivity. At this time, if a liquid crystal is used as the spatial filter, the shape of the spatial filter can be arbitrarily changed by turning on and off the liquid crystal, so that it is possible to automatically inspect an arbitrary repeated pattern.

  The above-described means improves the yield during semiconductor manufacturing for the following reasons. Through a rigorous detection experiment of the number of foreign objects on a semiconductor substrate, it was newly found that the number of foreign objects does not increase or decrease gradually but increases or decreases suddenly. Conventionally, since the number of foreign matters was considered to gradually increase or decrease, as described above, foreign matter inspection was performed at a frequency of one to one per lot, as described above. However, at this inspection frequency, a sudden increase in foreign matter is overlooked or detected after a while while increasing, resulting in a considerable number of defects. That is, in the mass production line, it is necessary to quickly detect the occurrence of foreign matter and take countermeasures. When time elapses from the occurrence of foreign matter to the detection of foreign matter, the number of defectives increases and the yield decreases. Therefore, a high yield can be maintained by shortening the elapsed time from the occurrence of a foreign object to its detection. In other words, it is possible to maximize the effect of foreign matter inspection by shortening the sampling time of the monitor, ideally, by sampling in real time.

  Further, in the conventional apparatus, the semiconductor substrate is extracted and inspected, and at this time, a new foreign substance adheres to the semiconductor substrate, which also reduces the yield. Since the foreign matter inspection apparatus according to the present invention can inspect without removing the semiconductor substrate, it is possible to eliminate the yield reduction due to the foreign matter adhering to the semiconductor substrate.

  According to the present invention, by introducing a foreign substance inspection apparatus into a line, all wafers passing through the line can be inspected, and an increase in foreign substances can be detected in real time. Thereby, the production of a large number of defective products due to the generation of foreign matter can be prevented in advance, and the yield can be improved.

  In addition, according to the present invention, the foreign matter is monitored by only a simple monitoring device in the mass production line of the semiconductor manufacturing process, so that the production line can be reduced in weight and the manufacturing cost can be reduced. Furthermore, since the monitoring device can perform the foreign substance inspection in real time, it can minimize the creation of defects and can greatly contribute to the improvement of product yield.

  FIG. 1 shows an example of a configuration block diagram of a mass production start-up and mass production line foreign matter inspection method and apparatus thereof in a semiconductor manufacturing process.

In FIG. 1, a mass production start-up and mass production line foreign matter inspection apparatus in this semiconductor manufacturing process is a semiconductor manufacturing system comprising an exposure apparatus 11, an etching apparatus 12, a cleaning apparatus 13, an ion implantation apparatus 14, a sputtering apparatus 15, a CVD apparatus 16, and the like. The sensing unit 20 and its sensing unit control system 25, the gas supply unit 31, and the water supply unit 32 including the device group 10, the temperature sensor 21, the foreign substance monitor 22 in the transport system, the pressure sensor 23, and the foreign substance monitor 24 in the processing apparatus. A sampling unit 40 including a utility group 30, a water quality sampling wafer 41, a gas sampling wafer 42, an in-device sampling wafer 43, a device wafer 44 and an atmosphere sampling wafer 45, a wafer foreign matter detection unit 51, and a pattern defect detection unit 52. And a scanning electron microscope Mirror (SEM) and secondary ion mass spectrometer (SIMS) 6
2, a scanning tunneling microscope / spectrometer (STM / STS) 63, an analysis unit 60 including an infrared spectroscopic analyzer 64, a foreign matter lethality determination system 71, a minute foreign matter cause investigation system 72, and a contamination source countermeasure system 73. And a corresponding system 70. These components are divided into a line-compatible online foreign matter inspection system 81 and a mass production start-up line foreign matter inspection system 82, which together constitute a mass production start-up and mass production line foreign matter inspection system 80 in the semiconductor manufacturing process. Make it.

  Therefore, as shown in the figure, separating mass production lines from mass production lines enables efficient operation of foreign matter detection, analysis, and evaluation equipment at mass production start-ups, enabling rapid start-up of mass production. The mass production line can be reduced in weight by making the inspection and evaluation equipment for foreign substances used in the mass production line as simple as possible.

Next, an embodiment of the foreign matter monitor 22 in the transport system and the foreign matter monitor 24 in the processing apparatus which are online monitors of the online foreign matter inspection system 81 will be described. FIG. 2 shows an example in which the foreign matter monitor 101, which is an online monitor, is applied to the transport system of the single wafer CVD apparatus 16 that has a large number of defects in the semiconductor manufacturing apparatus group 10. It comprises a loader 102 having a foreign matter monitor 101, a preliminary chamber 103, a reaction chamber 104, a heating unit 105, a gas system 106, a controller 107, and a host CPU 108. The product wafer 111 is transferred from the loader cassette 109 placed in the loader unit 102 to the spare chamber 103, the gate valve 112 is closed, and the spare chamber 103 is exhausted. Next, the gate valve 113 is opened, the product wafers 111 in the preliminary chamber 103 and the reaction chamber 104 are exchanged, the gate valve 113 is closed, and film formation is started in the reaction chamber 104. During film formation, the preparatory chamber 103 is returned to atmospheric pressure, the gate valve 112 is opened, the product wafer 111 is collected, and the foreign matter on the product wafer 111 is measured by the foreign matter monitor 101 while being transported to the unloader cassette 110. A foreign matter monitor 101 may be provided immediately before the gate valve 112 to compare foreign matter before and after film formation.

  Next, the configuration of the foreign object monitor 101 will be described with reference to FIG. First, the orientation direction of the product wafer 111 is detected by the wafer rotation direction detector 121 provided on the foreign matter inspection start side of the foreign matter monitor 101 to detect the rotation direction of the product wafer 111. Thereafter, foreign matter inspection on the product wafer 111 is performed on the entire surface by the foreign matter detection optical system 122. Next, the foreign matter information obtained from the foreign matter monitor 101 is processed by the foreign matter information processing system 123, and if there is a foreign matter abnormality, it can be notified by an alarm or the like, or the device main body 125 can be stopped by the device stop function 124. In addition, foreign matter is displayed by the keyboard 126 and the CRT 127. Furthermore, it is linked with the foreign substance analysis system 128 and can exchange data. For example, the data 128 can be obtained from the foreign matter information processing system 123 by sending a command for the desired data such as the name, location, and sampling of the product wafer 111 from the system 128. Here, in the foreign matter monitor 101, the foreign matter detection optical system 122 is separate from the foreign matter information processing system 123. Further, the foreign matter detection optical system 122 does not have a stage system and uses a transport system of the processing apparatus. It is made up. However, of course, a configuration having a stage system is also possible. Accordingly, the external dimensions of the foreign matter monitor 101 are such that the width W, the depth L, and the height H are each within 1 m, or the width W of the foreign matter monitor 101 is shorter than the width Ww of the wafer, thereby enabling miniaturization. Further, the foreign matter monitor 101 has an automatic calibration function, and the reflectance of the product wafer surface varies between manufacturing apparatuses and between processes. Therefore, the reflectance is automatically measured and fed back to the illumination light amount of the foreign matter detection optical system. This can be dealt with and does not require tedious calibration. Furthermore, the depth of focus d of the detection lens of the foreign object detection optical system 122 is calculated from the following equation and is as deep as 0.1 to 0.5 mm, so that automatic focusing is not required.

  Here, λ is the wavelength of light, and NA is the numerical aperture of the detection lens. Furthermore, since it is small in size, it is possible to replace the unit, and it has a structure that can be easily mounted and set in the device, so that maintenance is easy.

  The detection method of the wafer rotation direction detector 121 will be described with reference to FIG. The product wafer 111 passes under the illumination system having several light emitting points 131 along the wafer moving direction 133 and moves from the position 132 to the position 134. The locus 135 on the product wafer 111 of the illumination light emitted from the light emitting point of the illumination system of the wafer rotation direction detector 21 is shown in FIG. In the case of the light emission point A, the time As when the illumination light hits the product wafer 111 and the time Ae from which the illumination light deviates from the product wafer 111 are measured, and this is performed for the other light emission points B to G. The orientation of the orientation flat of the product wafer 111 is obtained from the above data and the moving time of the product wafer 111, and the rotation direction of the product wafer 111 is calculated. As a method for detecting the rotation direction of the product wafer 111, there are special mark detection such as scribe area detection, chip detection, and alignment mark detection.

  Therefore, the foreign matter monitor 101 is in contact with the rotation direction of the product wafer 111 obtained by the wafer rotation direction detector 121, and the orientation flat X axis of the orientation flat as shown in FIG. Information on the position of the detected foreign matter on the product wafer 111 is obtained based on orientation flat reference coordinates with the virtual origin 141 as the intersection of the Y axes or circuit pattern 142 reference coordinates with the intersection of the extension lines of the circuit pattern 142 as the virtual origin 143. Foreign matter coordinate management that can be obtained is possible.

  Further, as shown in FIG. 6, even if the rotation direction of each product wafer 111 is conveyed in various directions 142, 143, 144, and 145 as shown in FIG. It also has an apparatus-based foreign matter coordinate management that does not depend on the rotation direction of the product wafer 111, which is composed of the x-axis where the direction 150 and the outer periphery of the product wafer 111 are in contact with each other and the y-axis which is orthogonal to the direction 150. If dust is generated in the apparatus, a regular foreign matter distribution is shown as in 146.

  Further, since the wafer rotation direction detector 121 of the foreign object monitor 101 can detect the rotation direction of the product wafer 111 and simultaneously obtain the transfer speed of the product wafer 111, the detector is synchronized with the transfer speed of the product wafer 111. For example, the scanning speed of the CCD linear sensor can be changed. Therefore, stable detection performance can be obtained regardless of the conveyance speed of the product wafer 111.

  FIG. 7 shows an example of a configuration diagram of a foreign matter detection optical system 122 using a spatial filter having a high-speed foreign matter inspection on the product wafer 111 and a small structure. It comprises an oblique illumination optical system 151 and a detection optical system 152. The oblique illumination optical system 151 is composed of one or more illumination arrays as shown in the figure. The detection optical system 152 includes a lens array 153 as a detection lens, a spatial filter 154 on the Fourier transform plane of the lens array, and a detector 155 at the imaging position of the lens array.

FIG. 8 shows a configuration diagram of the oblique illumination optical system 151. Here, oblique illumination means illumination from a direction 164 inclined by θ from the normal 163 of the product wafer 111. A small and high-power semiconductor laser 161 is used as an illumination light source, and high-intensity coherent light illumination is enabled by an anamorphic prism 162. This is because the product wafer 111 is illuminated with coherent light to obtain a sharp Fourier transform image of the pattern of the product wafer 111 on the Fourier transform plane of the detection lens 153. Furthermore, the anamorphic prism 162 enables wide area illumination that is not affected by adjacent illumination components of the illumination array. If there is an influence of the adjacent illumination light, the Fourier transform image of the pattern by the adjacent illumination is shifted on the Fourier transform plane of the detection lens 153, the area of the overlapping Fourier transform image is increased, and the area of the filter portion of the spatial filter is also increased. This is because the amount of scattered light from the foreign matter passing through the spatial filter is reduced and the foreign matter detection performance is degraded.

  FIG. 9 shows the detection width of the detection optical system 152. The detection width 170 of the detection optical system 152 is the same as the width of the product wafer 111, and the entire surface of the product wafer 111 can be inspected at once by only one scan 156 of the feed 156 of the product wafer 111, which enables high-speed inspection. Become.

  FIG. 10 shows a case where a CCD linear sensor is used as the detector 155. In order to collectively detect the width of the product wafer 111, the CCD linear sensors 171 are arranged in a staggered manner as shown in the figure. In addition, the column B is deleted and the data in the column A is validated for the sensor overlapping portion 172.

  FIG. 11 shows a configuration diagram of the spatial filter 154. Each spatial filter 182 corresponds to each lens element 181 of the lens array 153.

  FIG. 12 shows a detailed view of the spatial filter 154. The diffracted light 191 from the regular repeating pattern on the product wafer 111 becomes a regular image 192 at the position of the spatial filter 154 on the Fourier transform plane of the lens array 153. Therefore, the regular repetitive pattern of the product wafer 111 can be shielded by the spatial filter 154 as shown in the figure, and is not captured by the CCD linear sensor 155 as a detector.

As the spatial filter 154, a dry plate type spatial filter is used that is created by baking a Fourier transform image of a repetitive pattern of the product wafer 111 on a dry plate. Therefore, the light from the regular repeating pattern of the product wafer 111 does not pass through the burned portion of the spatial filter 154. Alternatively, there is a liquid crystal type spatial filter using liquid crystal. First, a regular image 192 of the diffracted light 191 from the regular repeating pattern of the product wafer 111 at the position of the spatial filter 154 on the Fourier transform plane of the lens array 153 is detected by a TV monitor or the like, and corresponds to the image 192. The position of the liquid crystal element is stored. Next, by applying a voltage to the stored liquid crystal element portion, it is possible to shield light hitting that portion. Accordingly, by storing and formatting the driving liquid crystal elements corresponding to the image for each product wafer in each process, it is possible to perform a spatial filter by turning on and off the liquid crystal for each product wafer in each process.

  FIG. 13 shows a spatial filter group 1001 by a dry plate method corresponding to the product wafer 111 in each process. Spatial filters corresponding to the product wafer 111 in each process are created by a dry plate method, exchanged by a moving mechanism such as a linear guide stage as shown in the figure, and positioned with respect to the detection lens 153, so that product wafers in all processes 111 can be supported.

  FIG. 14 shows an AND space filter 221 using a dry plate method. By taking AND of the spatial filter of several kinds of processes, the number of spatial filters can be reduced, and light from the repetitive pattern of the product wafer 111 of several kinds of processes can be shielded by one AND spatial filter 222, 223. it can. Therefore, by using the AND spatial filter 221, the number of spatial filters can be reduced even when there are many processes, and the apparatus configuration can be simplified. In addition, this method can be used for a liquid crystal type spatial filter and can reduce the number of formats to be stored. However, the AND of the spatial filter in all steps can be taken and a single AND spatial filter is also possible, but the amount of scattered light from the foreign matter passing through the AND spatial filter is reduced, and the foreign matter detection performance is deteriorated.

  Next, FIG. 15 shows an embodiment of a configuration diagram of the foreign matter detection optical system 122 by partial inspection. A microlens group 231 is used as a detection lens, a spatial filter 232 is arranged on the Fourier transform plane of each microlens 231, and a CCD linear sensor 233 is arranged as a detector. Therefore, by using the microlens 231 having a high resolution, it is possible to detect even smaller foreign objects than using the lens array 153. However, in this method, inspection can be performed even when a conventional lens is used instead of the microlens 231 as a detection lens. As an example of the partial inspection, the inspection area can be validated by adjusting the pitch of the microlens group 231 to the chip interval of the product wafer 111.

  However, as shown by the hatched portion in FIG. 16, only one row of the microlens group 231 performs a partial inspection on the product wafer 111 and can perform a foreign substance monitoring function, but the entire surface of the product wafer 111 cannot be inspected. Here, reference numeral 236 denotes a detection width of one microlens 231. However, the entire surface of the product wafer 111 can be inspected by scanning the product wafer 111 several times. Alternatively, as shown in FIG. 17, by arranging the microlenses 241 in two or several rows in a staggered manner, the entire surface inspection can be performed with only one scan 156 of the product wafer 111. A spatial filter 242 is disposed on the Fourier transform surface of the microlens 241 and a CCD linear sensor 243 is disposed as a detector.

  In FIG. 15, as another embodiment, the oblique illumination system 151 is illuminated with a pulsed laser on the product wafer 111 with a wide area and high illuminance. Furthermore, if a two-dimensional CCD sensor or a TV camera 233 is used as a detector, detection can be performed over a wide area. Here, in the oblique illumination system 151, when pulse light emission is performed, the detector also detects in synchronization therewith.

  In the above, when the spatial filter is used, if the rotation direction of each product wafer 111 is transported at a constant value, for example, an orientation flat alignment mechanism is installed in the middle of the transport system of the apparatus, and the product wafer is directed in the direction of the spatial filter. By matching the direction of 111, spatial filter detection becomes possible. However, when the rotation direction of each product wafer 111 is conveyed in various directions, the direction of the repetitive pattern of the product wafer 111 also changes. Therefore, it is necessary to rotate the spatial filter in accordance with the rotation direction of the product wafer 111. When the microlenses shown in FIGS. 15 and 17 are used, the adjacent spatial filters are independent, and therefore each spatial filter may be rotated in accordance with the rotation direction of the product wafer 111. However, when a lens array is used, adjacent spatial filters are connected, so that the foreign object detection optical system 122 (253) is set to 254 in accordance with the rotation direction (rotation position of the orientation flat) 251 of the product wafer 111 as shown in FIG. It is necessary to rotate in the direction of 252. Of course, even when a microlens is used, the foreign matter detection optical system 122 may be rotated in accordance with the rotation direction 251 of the product wafer 111. Here, the direction of 251 and the direction of 252 are the same. The rotation angle is 45 ° at the maximum. In the case of FIG. 18, the detection width is increased by the amount of rotation.

  In addition, when a spatial filter is used, regular repeated pattern portions on the product wafer 111 can be inspected, but other portions cannot be inspected. Therefore, the data other than the regular repetitive pattern portion on the product wafer 111 is set as invalid data or a detection prohibited area by software or the like. However, in this case, all the points on the product wafer 111 are not monitored for foreign substances, but the product wafer 111 is monitored at a specific ratio. Even monitoring only the repetitive part is very effective.

  Next, FIG. 19 shows an example of a configuration diagram of the foreign object detection optical system 122 using white light illumination. The oblique illumination system 261 using white light and the detection optical system 262 include a lens array 153 and a detector 155. When this method is used, the foreign substance detection performance is lowered as compared with the spatial filter method. However, as shown in FIG. 20, the white light illumination detection 271 has a higher detection performance than the laser illumination detection 272 that does not use a spatial filter, and is not limited to a regular repetitive pattern portion on the product wafer 111. Can be inspected. Here, the detection output from the foreign matter uses the peak value of all patterns on the product wafer 111 as the reference 273.

Next, FIG. 21 shows an example of a configuration diagram of a foreign matter detection optical system by wafer comparison inspection. It comprises an oblique illumination optical system 151 and a detection optical system 152. The oblique illumination optical system 151 is composed of one or more illumination arrays as shown in the figure. The detection optical system 152 is a lens array 153 or a microlens group as a detection lens, a spatial filter 154 on the Fourier transform plane of the detection lens 153, a detector 155 at the imaging position of the detection lens 153, and a detection signal from the detector. It comprises an image processing system 280 for processing. First, the first product wafer 111 is detected and stored in the memory 282 as an image. Next, the detection image 281 obtained by detecting the second product wafer 111 and the first stored image 282 are compared by the comparison circuit 283 so as to reveal the foreign matter. The third and subsequent product wafer 111 detection images 281 are compared with the first or immediately preceding second stored image 282. In this embodiment, the spatial filter 154 is used to reduce pattern information. Therefore, an orientation flat alignment mechanism or the like is installed before detection by the foreign object detection optical system, and the rotation direction of all product wafers 111 is adjusted to the rotation direction of the spatial filter.

  FIG. 22 shows a system diagram of a semiconductor FA (Factory Automation) using the foreign object monitor 101. It consists of an integrated processing station 291 capable of processing the product wafer 111, various job stations 292 corresponding to various special processes, an inspection station 293, and an analysis station 294, and these stations are connected by a transport system in a clean tunnel. Yes. In the integrated processing station 291 and the various job stations 292, a foreign matter monitor 101 is mounted on a CVD device or an etching device that is particularly likely to have a large number of defects to monitor the foreign matter in the device. In addition, the foreign object monitor 101 is mounted on the transfer system at the entrance / exit of the station as in 296 and 297 to monitor the foreign object in the entire station.

  Of course, the present invention is effective for monitoring a mass production line even when mass production is started.

  Next, another specific embodiment of the small foreign matter monitor according to the present invention will be described with reference to FIGS.

  Hereinafter, the configuration of the present embodiment will be described with reference to FIG. In this embodiment, an illumination optical system 1110 including a semiconductor laser 1111, a collimator lens 1112, an x diffuser lens 1113, a condenser lens 1114, a y diffuser lens 1115, and a mirror 1116, an imaging lens 1211, 1221, and a spatial filter 1212 are used. 1222, polarizing plates 1213 and 1223, a detection optical system 1210 including a one-dimensional detector 1214 and 1224, and a stage system 1300 including a wafer transfer unit 1301, an automatic focus detector 1312, and an automatic focus positioning mechanism 1313. , An A / D converter 1411, a threshold circuit 1412, a two-dimensional image cutout circuit 1413, a pattern foreign matter determination circuit 1414, pattern information memories 1418 and 1416, foreign matter information memories 1417 and 1415, and an FFT circuit 1511 Repeating unit removal circuit 1512, a data memory 1513, a microcomputer 1515, the data display system 1516 composed of a configured data processing system 1501 from the abnormality display alarm 1517.

  In the illumination optical system 1110, the light emitted from the semiconductor laser 1111 becomes a plane wave by the collimator lens 1112 and is spread only in the x direction by the x diffusion lens 1113. The light emitted from the x diffusing lens 1113 is collected by the condenser lens 1114 into a light beam parallel to the x direction, that is, a plane wave, and condensed in the y direction. Thereafter, the light is diffused by the y diffusion lens 1115 only in the y direction to a parallel light beam. As a result, the x- and y-directions are parallel light beams, that is, plane waves and become linear beams that are long in the y-direction, and illuminate the wafer (semiconductor substrate) 1001.

  FIG. 24 shows the configuration of the illumination optical system 1110 viewed from the x direction, and FIG. 25 shows the configuration viewed from the y direction. In the y direction, the illumination area on the wafer (semiconductor substrate) 1001 is widened as much as possible, and is narrowed down to have sufficient illuminance in the x direction. However, the illumination is a plane wave, that is, a light beam parallel to both the x direction and the y direction.

  Here, in the present embodiment, illumination is performed using a parallel light beam, that is, a plane wave in both the x and y directions. However, any optical system that approximates a plane wave may be used. Further, here, the linearly polarized light is irradiated so that the magnetic field vector is perpendicular to the incident plane of illumination. This has the effect of improving the scattered light from the foreign material relative to the scattered light from the pattern. However, s-polarized light is not necessarily required, and other linearly polarized light, elliptical light, or circularly polarized light may be used to achieve the object of the present invention.

  In the detection optical system 1210, the light beam emitted from the inspection position 1002 on the wafer 1001 is imaged on the one-dimensional detectors 1214 and 1224 through the spatial filters 1212 and 1222 and the polarizing plates 1213 and 1223 by the imaging lenses 1211 and 1221. To do. The polarizing plates 1213 and 1223 block light (S-polarized light) whose magnetic field vector is perpendicular to the illumination incident surface. This polarizing plate has an effect of improving the scattered light from the foreign matter relative to the scattered light from the pattern. However, this is not always necessary and may be omitted to achieve the object of the present invention.

  Further, the imaging lens 1211 of the detection optical system may be a normal lens as shown in FIG. 26, or a refractive index change type lens array as shown in FIG. In any case, when an optical system capable of illuminating a plane wave as shown in FIGS. 24 and 25 is used as the illumination optical system 1110, there is no structural difference including the spatial filters 1212 and 1222.

FIG. 28 is a plan view of the illumination optical system and the detection optical system. A plurality of detection optical systems 1210, 1220, 1230, 1240, 1250, 1260 and one-dimensional detectors 1214, 1224, 1234, 1244, 1264 are arranged to cover the entire diameter L of the wafer. The illumination optical systems 1110, 1120, 1130, 1140, 1150, and 1160 are arranged so as to illuminate the detection areas of the one-dimensional detectors 1214 to 1264, respectively. With this configuration, the entire wafer can be illuminated with a parallel light beam, that is, a plane wave. In this configuration, one inspection area is illuminated from one illumination direction. With this configuration, the effect of the spatial filter is sufficiently exhibited. If one illumination region is illuminated from a plurality of directions, the diffraction patterns of these illuminations overlap on the spatial filter, so that it is necessary to enlarge the light shielding region by the spatial filter. When the light shielding area is enlarged as described above, the light signal to be detected is also shielded by the light shielding area. This can be prevented by illuminating from one direction.

  In stage system 1300, after wafer 1001 is placed on wafer transfer means 1301, wafer transfer means 1301 moves in the x direction. Here, the wafer transfer means 1301 is a transfer system of another processing apparatus, specifically, a semiconductor manufacturing inspection apparatus such as a film forming apparatus, an etching apparatus, and an exposure apparatus. Of course, the foreign matter inspection apparatus of the present invention may have this conveying means. Further, the distance between the wafer 1001 and the apparatus according to the present invention is measured by the automatic focus detection system 1312. Based on the result, control is performed so that the distance between the wafer 1001 and the apparatus according to the present invention is optimized by the automatic focus control system 1313. Is done. Although it is sufficient that this control is performed only once before the start of the inspection, depending on the accuracy of the wafer transfer means 1301, it may be necessary to control in real time during the inspection.

  In the signal processing system 1410, the detection signal from the one-dimensional detector 1214 passes through the A / D converter 1411 and the threshold circuit 1412, and the binarized 1-bit signal is a 5 × 5 two-dimensional image cutout circuit 1413. The pattern and foreign matter are determined by the pattern foreign matter determination circuit 1414 based on the logical expression shown in FIG. That is, assuming that the logical value of the central point is P (0, 0), when the following equation (Equation 2) holds, the signal of p (0, 0) is determined as a foreign object, and the following equation (Equation 3) When is established, it is determined as a pattern.

  The determined result is stored in the pattern memory 1415 and the foreign matter memory 1416 by a coordinate signal obtained from the basic clock of the one-dimensional detector 1214. Here, a plurality of circuits such as three systems from the threshold circuit 1412 to the foreign matter memory 1416 are prepared, and the threshold value of the threshold circuit 1412 is changed stepwise. Such a circuit configuration has the effect of reducing the circuit scale while having necessary and sufficient functions. Here, since this signal processing system processes the signals of the detection optical systems 1210 to 1260, signal processing systems 1410 to 1460 are provided.

In the data processing system 1501, the foreign matter map data is Fourier-transformed from the data in the foreign matter memory 1416 by the FFT circuit 1511, and the repeated portion between the chips is removed by the repeated portion removing circuit 1512. Coordinates and threshold values are stored in the foreign matter memory 1513 for the foreign matter data obtained in this way, and an alarm signal is output from the alarm 1517 when the number of foreign matters is larger than the allowable range. When this alarm signal is issued, the operator stops the operation of the line, pursues the cause of the occurrence of foreign matter, and takes countermeasures. Further, by giving a command from the microcomputer 515, foreign matter map data, coordinate data, and the like are output to the display system 1516. In the present invention, pattern data is also stored in the memory 1416. This data means that foreign matter inspection is not performed in this pattern portion. Therefore, the ratio of the pattern data to the entire area means the inspection area ratio. If this inspection area ratio is smaller than a predetermined value, there may be an error in the inspection apparatus or an error in the wafer process. Accordingly, also in this case, an alarm is issued from the alarm 1517.

  FIG. 51 shows a foreign matter pattern determination system that also functions as a signal processing system 1410 and a data processing system 1501. In the data processing system 1501, the non-repeated pattern around the chip is identified and removed using the repeatability of the chip in the wafer. This function is also achieved by the circuit shown in FIG.

  In this embodiment, an image clipping circuit 1420 is provided instead of the two-dimensional image clipping circuit 1413. The image cutout circuit 1420 includes cutout units 1421 and 1422 and a determination target unit 1423. The cutout parts 1421 and 1422 are arranged so as to cut out an image at a position apart from the chip pitch p on the sample with respect to the determined part 1423. Here, since the wafer has a chip error error Δp due to a rotation error Δα, a chip transfer error, an imaging magnification error, a binarization error, and the like, the image clipping units 1421 and 1422 are compared with the determination target 1423. In general, there is a margin of ± Δα and ± Δp. This value may be designed experimentally or based on the manufacturing accuracy of the apparatus. In this embodiment, the pixel size is 7 μm, Δp is 1.5 pixels, and Δα is 0.5 degrees. The pitch is about 10 mm and Δw (= Δα · p) is 12.5 pixels. The signal cut out from the image cutout circuit 1420 is processed according to the signal processing system shown in FIG. In the two-dimensional cut-out circuit 1413, a logical product is taken over the entire area of the cut-out parts 1421 and 1422, while the square peripheral part of the cut-out square is ANDed into a square shape according to the equation (1). That is, the two-dimensional clipping circuit 1413 uses P (i, j) as the peripheral portion of the cut-out square, whereas the cutting-out portions 1421 and 1422 use P (i, j) as the entire cut-out region. The pattern judgment is expressed by Equation 1 and the foreign matter judgment is expressed by Equation 2 only in the shape of P (i, j).

  In this configuration, the FFT circuit 1511 and the repetitive part removal circuit 1512 can be omitted.

  The operation will be described below with reference to FIGS.

  In the present invention, attention is paid to the repeatability of a pattern in order to inspect foreign matter on a VLSI with an ultrafine pattern formed with a high-speed, high-precision and small-sized apparatus. In the conventional apparatus, a large, high-performance apparatus has been used in order to inspect the entire area of the wafer with high speed and high accuracy. However, in order to improve the yield of semiconductor production, it turns out that it is better to carry out the whole wafer inspection at the expense of the whole area inspection rather than the foreign matter inspection for the entire area. did. As long as the conventional apparatus is used, the wafer can only be sampled and inspected at an appropriate frequency. With this inspection method, there is a possibility that a large number of defects will be created once a defect has occurred. When such an entire wafer inspection is performed, defects such as apparatus dust generation and process dust generation can be found without inspecting the entire area of the wafer.

  Therefore, attention was paid to the fact that a large number of repeated patterns exist in LSIs represented by memory. For DRAM, SRAM, etc., 80% or more, and for microcomputers, custom LSIs, etc., in many cases, 30% or more. With such a ratio, it is sufficient to inspect only this repeated portion. In the inspection of the defect and foreign matter in the repeated portion, the non-repeated portion enhancement detection technique using optical filtering is effective. Therefore, this technique was suitable. In this method, a method of creating a spatial filter is a problem.

  When the repetitive pattern of the basic pattern 1010 as shown in FIG. 29 is illuminated by the apparatus shown in FIG. 23, a regular diffraction pattern 1011 as shown in FIG. 30 is observed by the spatial filters 1212 and 1222. . This diffraction pattern 1011 is due to diffraction from the pattern shown in FIG. Here, when the foreign material 1012 exists on FIG. 29, the diffracted light from the foreign material 1012 has an irregular shape different from the regular diffraction pattern 1011. For example, as shown by a pattern 1013 in FIG. Observed. Therefore, if a filter that blocks the diffraction pattern 1011 is provided on the spatial filters 1212 and 1222, the information on the pattern 1014 is deleted, and only the information on the foreign matter 1012 is displayed on the one-dimensional detectors 1214 and 1224 in FIG. Observed as follows. That is, according to the present invention, only the foreign material 1012 is selectively detected.

  Here, the relationship between the pitch p of the pattern 1014 and the pitch θ of the diffraction pattern 1011 (indicated by the angle of the diffraction pattern incident on the imaging lenses 1211 and 1221 from the observation point 2) is the emission of the illumination optical system 1110. The wavelength λ of the light to be transmitted is expressed by the following equation (Equation 4).

  Therefore, as p decreases, θ increases. That is, there is an advantage that as the LSI becomes finer and p becomes smaller, θ of the diffraction pattern increases and the diffraction pattern incident on the imaging lens 211 decreases and the shape of the spatial filter becomes simple.

  In the case of the same product, even if the shape of the basic pattern 1010 changes, the position pitch does not change, so the basic shape of the diffraction pattern does not change. That is, as long as the same product is inspected, the shape of the diffraction pattern is not substantially changed, and therefore the shape of the spatial filter that shields the diffraction pattern is not substantially changed. Using this feature, even if a spatial filter that measures the shape of the diffraction pattern of each process for each product and shields all the diffraction patterns is created, the filter blocks all the apertures of the imaging lens. We focused on the fact that there was no such thing. In this way, by using a filter that shields all the diffraction patterns for each process, the replacement of the spatial filter can be omitted. In particular, the memory production line is effective because the number of products is small and the number of product changes is small.

  Here, in the present invention, if a refractive index change type lens array is used for the imaging lenses 1212 and 1222, the apparatus can be further reduced in size. The refractive index change type lens array is used in facsimiles, electronic copying machines, and the like because a small optical system can be formed. In order to achieve the objective of reducing the size of the optical system, this refractive index change type lens array is effective. However, in the present invention, it is necessary to use a spatial filter. Conventionally, attention has not been paid to the fact that a refractive index change type lens array also has a Fourier transform surface and a spatial filter can be used. In the present invention, focusing on the fact that a spatial filter can be used for this refractive index change type lens array, a small foreign matter monitor using the refractive index change type lens array has been realized. The configuration and operation of the spatial filter are the same as those described above, and the above-described spatial filter may be installed for each lens. Further, the position of the spatial filter of this refractive index change type lens array is the end face on the exit side of the lens as shown in FIG.

  FIG. 32 shows the shape of the spatial filter. In particular, the straight line shown in FIG. 32A is preferable in order to produce the effect most easily and for an arbitrary pattern. Further, in order to obtain the discrimination performance from the pattern by the spatial filter on the straight line, a shape as shown in FIG. 32B is required. Furthermore, FIG. 32C shows an example of a shape that can be used in all the steps in the product.

  FIG. 33 shows an example of foreign object detection.

  Here, in realizing a high-speed and small-sized foreign substance inspection apparatus, the method using this spatial filter is more suitable than the polarization detection method shown in the prior art (Japanese Patent Publication No. 62-89336). The reason for this will be described with reference to FIGS.

  In the method of illuminating the sample and detecting the scattered light from the foreign matter, the scattered light from the pattern formed on the sample surface becomes noise. As shown in FIG. 34C, this noise increases as the pixel size (the minimum unit detected as one signal) of the detector 2006 increases. Since the noise source pattern is formed on almost the entire surface of the sample, the noise increases in proportion to the pixel size.

  On the other hand, since the inspection time increases as the number of pixels increases, it is necessary to increase the pixel size in order to realize high-speed inspection. Therefore, it is necessary to increase the pixel size and reduce the noise level. As a method of reducing this noise level, Koizumi et al., “Analysis of reflected light from LSI wafer pattern”, Transactions of the Society of Instrument and Control Engineers, 17-2, 77/82 (1981), analyzed the method using polarized light. Has been. According to this, the scattered light (noise) from the pattern can be attenuated by using polarized light. However, the decay rate of scattered light by this method depends on the direction of the detector, as analyzed in the above paper. For this reason, when collecting the light emitted in various directions as in the case of using the imaging optical system, the attenuation rate is about 0.1% to 0.01% when the attenuation rates are integrated.

  On the other hand, in the method using the spatial filter of the present application, the attenuation rate can be changed from 0.001% to 0.0001%. The reason for this will be described with reference to FIGS. The wafer 2001 on which the repetitive pattern is formed is illuminated with illumination light 2002, and the illuminated area is imaged on the detector 2006 using lens systems 2003 and 2005. Here, the intensity distribution of the emitted light from the pattern on the Fourier transform plane on which the spatial filter 2004 is placed is shown in FIG. Light emitted from the repetitive pattern is concentrated at a position corresponding to the pitch of the pattern. As an example of calculating the concentration ratio, the diffracted light intensity distribution in the case of a double slit is explained by Hiroshi Kubota, “Applied Optics” (Iwanami). According to this, the concentration ratio increases as the number of slits (in the present application, the number of repetitive patterns illuminated simultaneously) increases. This ratio can also be calculated using the Fourier transform F []. If the shape of the illuminated pattern is a (x, y), the light intensity distribution at the position of the spatial filter is F [a (x, y)]. When the shape of the spatial filter is p (u, v), p (u, v) * F [a (x, y)] is the light that passes through the spatial filter. If the shape of a figure complementary to the spatial filter is ￣p (u, v), ￣p (u, v) * F [a (x, y)] is a light component shielded by the spatial filter. . The ratio of these two components is the previous attenuation factor. The attenuation factor when the number of pattern repetitions is 3 is about 0.001%. When the number of repetitions is 5, it becomes about 0.0001%, and when the number of repetitions is further increased, the attenuation rate decreases. Therefore, the attenuation rate can be made lower than that using polarized light, and pattern noise can be reduced.

  The above calculation is an ideal case where the pattern shape and other conditions are ideal, and may not necessarily match the actual experimental result. However, an experimental result has been obtained that the attenuation factor is reduced by one to three digits compared to the polarization method, and the pattern noise can be reduced.

  Next, another embodiment of the small foreign matter monitor of the present invention will be described with reference to FIGS. FIG. 34 shows the relationship between the detection pixel size of the foreign object detector and the noise level. A problem with small foreign matter monitors is high speed and downsizing. FIG. 1A shows a foreign matter detection optical system. Scattered light from the pattern and foreign matter on the wafer 2001 is detected by the detector 2006 through the detection lens 2003. A detection signal from the detector 2006 is output for each pixel of the detector 2006. FIG. 2B shows a case where the size on the wafer corresponding to one pixel of the detector 2006 is a small pixel and a case where the size is a large pixel. The detection time T is expressed by the following equation (Equation 5) as the area S of the wafer, the data acquisition time t of the detector, the pixel size w of the detector, and the number of pixels n of the detector.

  From Equation (5), in order to achieve high speed and small size, it is most effective to increase w and increase n to perform parallel processing. However, as shown in FIG. 5C, when w is increased, the noise level from the pattern on the wafer 2001 increases in proportion to w. Therefore, in order to increase w and maintain the foreign object detection performance, it is necessary to reduce the noise level from the pattern.

  Then, next, the effect of noise reduction by the spatial filter method will be described in order to reduce the noise level from the pattern. FIG. 35 shows a configuration diagram of a foreign matter detection optical system using a spatial filter. A spatial filter 2004 is installed on the Fourier transform plane of the detection lens 2003. Diffracted light 2007 from a repetitive memory pattern on the wafer 2001, which is noise, passes through the detection lens 2003 and is then shielded by the spatial filter 2004. Scattered light 2008 from the foreign matter on the wafer 2001 passes through the detection lens 2003, the spatial filter 2004, and the imaging lens 2005 and is detected by the detector 2006.

Here, the light intensity distribution in the x direction of the pattern diffracted light 2007 on the surface of the spatial filter 2004 in FIG. 35 is shown in FIG. In the figure, the ratio of the light intensity of the pattern diffracted light 2007 corresponding to the transmission part (A) and the light shielding part (B) of the spatial filter 2004, that is, A: B is 1:10 ⁵ , and the spatial filter 2004 is installed. Thus, the pattern noise can be reduced to 1/10 ⁵ . In the polarization filter method used in the conventional foreign matter inspection apparatus, the pattern noise reduction is 1/10 ^2. Therefore, if the pixel size of the detector is the same, the noise reduction level is improved by 10 ³ and the foreign matter detection sensitivity is also improved. improves. Therefore, by setting the target setting of the foreign matter detection sensitivity below the performance of the conventional foreign matter inspection apparatus, the pixel size of the detector can be increased, and the foreign matter detection optical system can be increased in speed and size. .

  The pattern that can be shielded by the spatial filter is a repetitive memory pattern, and the data other than the memory pattern portion is set as invalid data or a detection prohibited area by software or the like.

  FIG. 37 shows the discrimination ratio in the foreign matter detection optical system when the spatial filter method is applied. Here, since the detection lens 2003 in the foreign matter detection system optical system also serves as an imaging lens, no imaging lens is required. From the detection signal distribution from the detector 2006, if the detection signal of foreign matter is S and the pattern noise is N, the discrimination ratio is represented by S / N. Next, FIG. 38 shows the relationship between the pixel size of the detector and the discrimination ratio. Here, an example of 2 μm standard particles is shown as the foreign matter. A discrimination ratio of 1 or more is required in order to discriminate foreign substances stably from the pattern. Therefore, it can be seen from the figure that the pixel size of the detector should be 20 μm or less in order to discriminate and detect 2 μm standard particles from the pattern.

  Next, FIG. 39 shows an illumination area and a detection area. The inspection time T is expressed by the following equation (Equation 6) as the inspection widths Lx and Ly, the pixel size w of the detector, and the reading clock frequency f of the detector.

The effective illumination light intensity P is expressed by the following equation (Equation 7) as illumination power P ₀ , illumination widths Wx, and Wy.

  Here, since Wx≈Lx, Expression (Expression 7) is expressed by Expression (Expression 8).

  The total illumination light amount Pt is expressed by the equation (Equation 9) from the equation (Equation 6) and the equation (Equation 8).

Accordingly, the detection signal intensity I is expressed by the equation (Equation 10) from the foreign substance signal coefficient K ₂ and the equation (Equation 9).

  From Equation (10), I is a function of w · f.

  Based on the above results, FIG. 40 shows a performance diagram for determining the device specifications. The apparatus specifications are determined based on the relationship between the pixel size and the inspection time, the relationship between the pixel size and the discrimination ratio, and the relationship between the pixel size / detector clock frequency and the detection signal. For example, in order to realize an inspection time of 20 seconds, if the clock frequency of the detector is set to 2 MHz from the relationship between the pixel size and the inspection time, the pixel size of the detector may be 13 μm. At that time, from the relationship between the pixel size and the discrimination ratio, the discrimination ratio from the pattern of 2 μm foreign matter is 2, and can be discriminated from the pattern. Finally, from the relationship between the pixel size / detector clock frequency and the detection signal, the 2 μm foreign object detection signal is determined by the pixel size / clock frequency and is 60 mV, and can be detected by the detector. As described above, the specifications of the detected foreign matter size and inspection time of the apparatus can be arbitrarily determined from the three performance diagrams.

FIG. 41 is a diagram showing a device configuration of a foreign matter detection optical system using a spatial filter method. The foreign matter detection optical system is configured such that the entire surface of the product wafer 2001 can be inspected by uniaxial scanning 2010 of the product wafer 2001. Therefore, the foreign matter detection optical system is divided into an illumination optical system 2011 and a detection optical system 2013, and each has a unit configuration. A case where the inspection target wafer is φ200 mm will be described below. For example, in order to inspect the entire width of the wafer 2001 with 8 units, the illumination area and detection area 2012 of 1 unit may be set to 25 mm. Therefore, when the inspection target wafer is φ150 mm, 6 units out of 8 units may be used. One unit of the detection optical system 2013 includes a detection lens 2014, a spatial filter 2015 installed on the Fourier transform plane of the detection lens 2014, and a linear sensor 2016 as a detector. When the outer dimension of the detection lens 2014 is larger than the detection width, the entire width of the wafer 2001 can be ensured by arranging in a staggered manner as shown in FIG. Further, when the outer dimension of the detection lens 2014 is equal to or smaller than the detection width, or in the case of inspection limiting the wafer, that is, partial inspection, it can be arranged in a straight line. The spatial filter 2015 used here uses two sets of four unit configurations when the detection optical system 2013 is staggered, and uses one set of eight unit configurations when the detection optical system 2013 is linear. The detection signal from the linear sensor 2016 is processed by a foreign object detection process (separate) 2017 and is output as foreign object data.

  When the detection optical system 2013 is staggered, it is necessary to replace two sets of spatial filters 2015 between two types of wafers 2001 when the detection optical system 2013 is a straight line. There is almost no dependence, and one kind of wafer can be handled by one kind of spatial filter 2015.

Next, an example of the specification in the present embodiment will be shown. The illumination optical system uses a semiconductor laser having a wavelength of 780 nm and an output of 200 mW as an illumination light source, and illuminates a 26 × 1 mm ² region on the wafer at an illumination light incident angle of 60 ° from above. The detection optical system uses a projection lens (50 mm F2.8 as a detection lens) and detects with a detection magnification of 1 (detection NA = 0.1). The detector has a pixel size of 13 μm, a pixel count of 2048, and a drive frequency of 4 MHz CCD. A linear sensor or a CCD linear sensor with a pixel size of 7 μm, a pixel count of 4096, and a driving frequency of 4 MHz with high foreign substance discrimination performance is used.

  Next, FIG. 42 is an example showing the influence of pattern noise light due to the wafer rotation angle. When the wafer 2001 rotates, the diffracted light from the pattern of the wafer 2001 also rotates according to the wafer 2001. Therefore, when the wafer 2001 is rotated with respect to the foreign matter detection optical system 2021, diffracted light from the pattern of the wafer 2001 leaks from the light shielding portion of the spatial filter of the foreign matter detection optical system 2021. Therefore, the leakage light of the diffracted light from the pattern, that is, the pattern noise light is a function of the light shielding width of the spatial filter and the rotation angle of the wafer. Here, the rotation angle θ of the wafer represents the angle between the center line 2020 of the foreign matter detection optical system 2021 and the center line 2000 of the wafer 2001. However, if the light shielding width of the spatial filter is increased, the scattered light from the foreign matter is also reduced, so it is necessary to obtain an optimum width. Therefore, with the conventional pre-alignment device, the rotation angle of the wafer can be suppressed within ± 2 °, so that the foreign matter detection performance, for example, the light shielding width of the spatial filter that can detect and detect 2 μm foreign matter from the pattern is the optimum width. An example of the change in pattern noise light due to the rotation of the wafer is shown in FIG.

  In order to have a function as a monitor for foreign object inspection, a foreign object detection system having a focal depth as deep as possible is necessary.

  The depth of focus can be larger than the depth of focus calculated from the NA of the detection lens depending on the size of the detected pixel size.

  If the detection pixel size is sufficiently smaller than the detection foreign matter size, the focal depth d depends on the numerical aperture of the detection lens, and is expressed by the following equation (Equation 11) as the light wavelength λ and the numerical aperture NA of the detection lens.

  In the equation (Equation 11), for example, when λ = 780 nm and NA = 0.1, d = 39 μm. If the detected pixel size is sufficiently larger than the detected foreign substance size, the depth of focus depends on the detected pixel size. In this case, if the detected pixel size is the equivalent resolution a ′, the relationship with the equivalent numerical aperture NA ′ is expressed by the following equation (Equation 12).

  Furthermore, when NA ′ in the equation (Equation 12) is substituted into the NA in the equation (Equation 11), the actual depth of focus d is obtained. For example, if a ′ = 13 μm, NA ′ = 0.037 and d = 285 μm.

  Therefore, there is an effect of increasing the depth of focus of the foreign object detection system by increasing the number of pixels of the detector.

  FIG. 43 is an example showing a change in the foreign matter detection output depending on the height of the wafer stage. This shows a change in detection output of a 5 μm foreign matter when λ = 780 nm, NA = 0.1, and a detection pixel size of 13 μm. From the figure, the depth of focus is ± 70 μm. This value is a value between the value (39 μm) obtained from the numerical aperture of the detection lens and the value (285 μm) obtained from the detection pixel size. Accordingly, the detection pixel size of 13 μm is not sufficiently large for a foreign substance of 5 μm, but the depth of focus is increased.

  As described above, by reducing the numerical aperture of the detection lens and increasing the detection pixel size, the depth of focus can be increased and the position control in the height direction of the wafer transfer system can be made rough. Is possible.

  Next, the configuration of one unit of the illumination optical system used in the small foreign matter monitoring apparatus will be described. One side of the wafer is widened so that the inspection area can be sufficiently illuminated, and one side is narrowed down to have sufficient illuminance so that linear illumination is possible. If the illumination light source is a point light source, a plane wave, that is, a parallel light beam is generated on both sides. Here, when the illumination light is parallel light, the image of the spatial filter position of the detection optical system can be sharpened, the light shielding performance of the pattern by the spatial filter can be enhanced, and the foreign matter detection performance can be enhanced. However, for example, when a small semiconductor laser is used as the illumination light source, the length of one side of the light emitting point becomes longer as the output becomes higher. Therefore, one side cannot produce a plane wave, that is, a parallel light beam. Accordingly, two examples of illumination optical systems corresponding thereto are shown. However, in the linear illumination on the wafer, the long direction of the beam is the y direction, and the short direction of the beam is the x direction.

  The configuration of the first method is shown in FIG. 44, the configuration viewed from the x direction is shown in FIG. 4A, and the configuration viewed from the y direction is shown in FIG. Here, the long direction of the light emitting point 2100 of the semiconductor laser 2101 is the x direction, and the short direction of the light emitting point 2100 (close to the point light source) is the y direction. However, a λ / 2 plate is inserted so as to be S-polarized illumination if it is P-polarized illumination on the wafer.

In the x direction of FIG. 6A, the light emitted from the semiconductor laser 2101 illuminates the wafer 2001 by using the lens 2102 to the lens 2106 and narrowing the light beam. In the y direction of FIG. 5B, the light emitted from the semiconductor laser 2101 uses the lens 2102 to the lens 2106 to spread the light beam into parallel light. Since this method can easily narrow the light flux in the x direction, it is possible to increase the illumination intensity. In this method, since the light beam in the x direction is narrowed at a certain angle instead of parallel light, the diffraction pattern in the x direction on the spatial filter surface of the detection optical system becomes long. However, a linear spatial filter as shown in FIG. 32 is used. Therefore, the diffracted light from the pattern can be shielded. FIG. 45 shows an example of a plan view of the diffraction pattern on the wafer on the spatial filter surface of the detection / detection optical system when the illumination optical system of FIG. 44 is used. The size of one point of the diffraction pattern from the pattern on the wafer is y1 = several mm depending on the numerical aperture of the illumination in the x direction and y1 = several μm because the y direction is parallel light, and only the y direction is sharp. Light. When the pitch py in the y direction is shorter than the pitch px in the x direction, as shown in FIG. 5A, the light shielding rate of the spatial filter increases and the detection output from the foreign matter also decreases. Therefore, by rotating the wafer by 90 °, the diffraction pattern from the pattern on the wafer becomes as shown in FIG. 5B, and the pitch in the y direction is the same as px in FIG. The light shielding performance can be improved. As described above, the detection output from the foreign matter can be further improved by setting the orientation of the wafer in advance so that the longer diffraction pattern pitch is in the y direction. The optimum orientation of the wafer can be input in advance as data. Further, once the direction of the diffraction pattern is observed, the optimum direction of the wafer is detected, and thereafter, the upper part of the optimum direction is used.

  The configuration of the second system is shown in FIG. 46, FIG. 46A shows the configuration viewed from the x direction, and FIG. 46B shows the configuration viewed from the y direction. Here, the short direction (close to the point light source) of the light emitting point 2100 of the semiconductor laser 2101 is the x direction, and the long direction of the light emitting point 2100 is the y direction. However, a λ / 2 plate is inserted so as to be S-polarized illumination if it is P-polarized illumination on the wafer.

  In the x direction of FIG. 6A, the light emitted from the semiconductor laser 2101 uses the lenses 2202 to 2207 to squeeze the light beam into parallel light. In the y direction of FIG. 6B, the light emitted from the semiconductor laser 2101 uses the lenses 2202 to 2207 to spread the light and illuminate the wafer 2001. However, since the light emitting point 2100 in the x direction is as long as several tens of micrometers, it cannot be made parallel light. Here, the light source 2100 forms an image at the position of the spatial filter 2015 through the lens 2202 to the lens 2207 and the imaging lens 2014. The total imaging magnification is optimally about several tens of μm or less because of the light shielding performance of the spatial filter.

  FIG. 47 shows an example of a plan view of a diffraction pattern from a pattern on the wafer on the spatial filter surface of the detection / detection optical system when the illumination optical system of FIG. 46 is used. The size of one point of the diffraction pattern from the pattern on the wafer on the spatial filter surface is about x2 = 100 μm because the x direction is parallel light, and y2 is several tens of μm because the y direction is proportional to the size of the illumination light source. Thus, regardless of the orientation of the wafer, relatively sharp light can be obtained in both the x and y directions, and the light shielding performance of the spatial filter can be enhanced.

  Next, another embodiment of the foreign matter detection optical system according to the polarization detection method of the small foreign matter monitor of the present invention will be described with reference to FIGS.

  The polarization detection method is not limited to memory patterns, and can detect and detect foreign substances from all patterns on the entire wafer surface.

FIG. 48 shows a configuration diagram of a foreign object detection optical system using a refractive index change type lens array as a detection lens. It consists of an oblique illumination optical system 3002 and a detection optical system 3003. The oblique illumination optical system 3002 is composed of one or more illumination arrays as shown in the figure. The detection optical system 3003 includes a refractive index variable lens array 3004 as a detection lens, a polarizing plate 3005 as a polarizing element, and a detector 3006 at the imaging position of the refractive index variable lens array 3004. Linear illumination is performed to illuminate the entire width of the wafer by the illumination array, and the entire width of the wafer is detected. Therefore, the entire surface of the wafer 3001 can be inspected by the uniaxial scanning 3010 of the wafer 3001. The illumination angle of the illumination array 3002 is several degrees above the horizontal direction, and the wafer 3001 is irradiated with linearly polarized light (S-polarized light) such that the magnetic field vector is perpendicular to the illumination incident surface. Further, the scattered light from the pattern and foreign matter on the wafer 3001 passes through the refractive index change type lens array 3004, and then is only P-polarized light (linearly polarized light whose magnetic field vector is parallel to the illumination incident surface) by the polarizing plate 3005. , The scattered light from the pattern is reduced, and the scattered light from the foreign matter is emphasized and detected by the detector 3006.

FIG. 49 shows an apparatus configuration diagram of a foreign object detection optical system using a normal lens as a detection lens. The foreign matter detection optical system has a configuration in which the entire surface of the product wafer 3001 can be inspected by the uniaxial scanning 3110 of the product wafer 3001. Therefore, the foreign matter detection optical system is divided into an illumination optical system 3111 and a detection optical system 3113, and each has a unit configuration. A case where the inspection target wafer is φ200 mm will be described below. For example, in order to inspect the entire width of the wafer 3001 with 8 units, the illumination area and detection area 3112 of 1 unit may be 25 mm. Therefore, when the inspection target wafer has a diameter of 150 mm, 6 units out of 8 units may be used. One unit of the detection optical system 3113 includes a detection lens 3114, a polarizing plate 3115, and a linear sensor 3116 as a detector. When the outer dimension of the detection lens 3114 is larger than the detection width, the entire width of the wafer 3001 can be ensured by arranging them in a staggered manner as shown in FIG. Further, when the outer dimension of the detection lens 3114 is equal to or smaller than the detection width, or in the case of inspection limiting the wafer, that is, partial inspection, the detection lens 3114 can be arranged in a straight line. The illumination angle of the illumination unit 3111 is several degrees above the horizontal direction, and the wafer 3001 is irradiated with linearly polarized light (S-polarized light) such that the magnetic field vector is perpendicular to the illumination incident surface. The scattered light from the pattern and foreign matter on the wafer 3001 passes through the detection lens 3114, and then passes only P-polarized light (linearly polarized light having a magnetic field vector component parallel to the incident plane of illumination) through the polarizing plate 3115. The linear sensor 3116 detects the light scattered from the foreign matter while enhancing the scattered light from the foreign matter. A detection signal from the linear sensor 3116 is processed by a foreign object detection process (separate) 3117 and is output as foreign object data.

  FIG. 50 shows the positioning and function of the present invention. One of the main tasks in the mass production start-up of LSI is to investigate the cause of foreign matter generation and take countermeasures, and to detect the generated foreign matter and analyze the element type, etc. A big clue. On the other hand, in the mass production line, it is necessary to quickly detect these foreign substances and take countermeasures. When the time from the occurrence of a foreign object to its detection elapses, the number of occurrences of defects increases and the yield decreases. Therefore, in order to maintain a high yield, it is indispensable to shorten the elapsed time from the occurrence of a foreign object to its detection. Further, it has been newly found out that the number of foreign matters does not increase or decrease gradually, but suddenly increases or decreases by a rigorous detection experiment of the number of foreign matters on the wafer. FIG. 2A shows a time transition of the number of foreign matters on a product wafer generated in a processing apparatus such as CVD. The conventional system is shown in FIG. The conventional apparatus is a stand-alone type, which is a sampling inspection in which a wafer processed in a mass production line is brought into a place of an inspection apparatus to inspect foreign matter. Therefore, since time is required for wafer conveyance and foreign matter inspection, the inspection frequency, that is, sampling is one lot, one lot, or one lot per day, as shown in FIG. There was a limit. In such sampling, a sudden increase in foreign matter is overlooked, or it is detected after a while while increasing, and a considerable number of defects (poor defects) occur. That is, in such sampling, it cannot be said that the occurrence of a foreign substance is detected sufficiently early. Therefore, as shown in FIG. 5C, a small foreign matter monitor having a compact foreign matter monitoring device is placed in the input / output port of the processing device or in the transport system between the processing devices, and the foreign matter data from the small foreign matter monitor is received. By taking in the foreign matter management system, the foreign matter can be managed on a single sheet. Therefore, by using this small foreign matter monitor, as shown in FIG. 5A, the monitor sampling time can be shortened, the real time sampling of the single wafer can be performed, and the effect of the foreign matter inspection can be maximized. it can.

  The function of the present invention includes the following five items. Size that can be attached to the processing system's transfer system, that is, small size, high-speed inspection that enables single wafer inspection of wafers, and low cost that can be an option for processing equipment so that foreign matter can be managed for each processing equipment It is a reasonable price. The monitor is easy to set up and maintenance free.

  Hereinafter, embodiments of the spatial filter will be described with reference to FIGS. 52 to 55. This spatial filter may be configured using a liquid crystal display element, but in the case of a liquid crystal element, only light having a specific polarization direction can be used. In addition, since the light attenuation factor is small, there is a problem that the diffracted light from the pattern cannot be sufficiently shielded. Therefore, it is preferable to mechanically configure the spatial filter using a metal plate or the like.

  The spatial filter is composed of a set of linear patterns as described with reference to FIGS. (Of course, the spatial filter is preferably a set of points that are slightly larger so as to shield the set of points as shown in FIG. 45 (a), but a set of straight lines as shown here is sufficient. The function is fulfilled and the structure is simple.) The pitch and phase of the linear pattern may be matched. FIG. 52 shows an embodiment of the variable pitch spatial filter 1270 using this metal plate.

  This embodiment is the same as the embodiment shown in FIG. 23 in that it includes an illumination optical system 1110, a detection optical system 1210, a stage system 1300, and a signal processing system 1401 and a data processing system 1501.

  Here, when the emission port 1021 of the semiconductor laser 1111 is arranged vertically as shown in FIG. 52, when the illumination system of FIG. 44 is used, the linear direction of the spatial filter is the incidence of the illumination light beam as shown in FIG. Parallel to the surface. In this case, as the alignment of the spatial filter, it is only necessary to adjust the pitch of the linear pattern with reference to the linear pattern at the center of the spatial filter. In this case, the pitch variable mechanism of the spatial filter can be simply configured.

  The configuration of the variable pitch spatial filter 1270 of FIG. 52 is shown in FIG. The pitch variable spatial filter 1270 is composed of a plurality of linear patterns 1271, a spring-like support 1272, a support 1273, a fixing means 1274, a screw 1275, a screw, which are made of a material having a high light shielding rate such as metal, metal oxide, or plastic. The driving unit 1276 is configured. Here, the screw 1235 is formed with a right screw at 1277 part and a left screw at 1278 part. Here, the pitch between the linear patterns 1271 can be changed by rotating the screw 1275 by the screw driving means 1276. The driving of the screw driving means 1276 is controlled in accordance with the value calculated for the pitch between the linear patterns 1271 by receiving the cell pitch d in the chip simultaneously with the chip pitch p on the wafer when the wafer is loaded. Here, the spring-like support 1272 may be rubber.

  Here, it is difficult to change the pitch of the spatial filter 1270 with a wide dynamic range. For example, when the pitch is 1/10, the screw 1275 needs to be ten times as long as the space filter. Therefore, when a plurality of spatial filters 1270 are installed in a stacked manner and the pitch is changed to be small, it is changed by the previous variable mechanism while being superposed, and when the pitch is greatly changed, it is reduced by shifting each of the stacked spatial filters. The pitch can be realized. Of course, it can be shifted simultaneously with the variable mechanism if necessary.

  Here, the linear pattern 1279 at the center of the spatial filter 1270 is preferably configured to be thicker than the other linear patterns. This is because the diffracted light at the center, that is, the 0th-order diffracted light has a high light intensity and the width of the intensity distribution of the diffracted light is wide, so that a wide linear pattern is necessary to sufficiently shield the diffracted light. is there.

  In addition, although one embodiment of the drive mechanism is shown here, it is not necessary to be the embodiment shown here in practicing the present invention, and any configuration that drives the linear pattern 1271 having a high light shielding property can be used. Other drive mechanisms may be used. Specifically, the configuration shown in FIG. 54 may be used. In this embodiment, the linear pattern 1271 is supported by a link 1291, and the pitch is changed by changing the inclination of the link 1291 by the link driving mechanism 1292.

  Further, it is better to set the orientation of the wafer in the direction in which the pitch of the spatial filter can be increased, that is, in the direction in which the pitch d of the pattern on the wafer is small. As shown in FIGS. 55 and 56, when the optical system shown in FIG. 45 is used as the illumination optical system 1110, a slightly larger linear spatial filter 1279 is arranged in the center of the spatial filter in parallel with the incident plane of illumination. However, it is necessary to arrange a linear pattern perpendicular thereto. In this case, it is necessary to adjust the pitch and phase as alignment of the spatial filter. If the incident angle of illumination is α, the exit angle of the linear diffraction pattern is θn, the wavelength of the illumination light is λ, and the basic pitch of the pattern on the wafer is d, the following equation is established.

  Therefore, it is necessary to configure a variable mechanism that satisfies this equation (Equation 13). Specifically, the pitch variable spatial filter 1270 shown in FIG. 55 is arranged in a direction rotated by 90 degrees, and in addition to adjusting the pitch, the entire pitch variable spatial filter 1270 is moved in a direction perpendicular to the linear pattern 1271. To adjust the phase. This phase adjustment is performed by the phase adjustment means 1281. In this configuration, a light shielding plate about 1 to 3 times as large as the linear pattern may be disposed at the center position of the spatial filter and slightly thicker parallel to the illumination incident surface.

  The thickness of the linear pattern is preferably obtained experimentally, but should be set to 10 to 20% of the size of the image on the spatial filter of the light source 1111 of the illumination system in terms of design. . However, when considering the accuracy of the adjustment mechanism of the spatial filter, it is necessary to provide a larger margin.

  Further, although the configuration of FIG. 23 is described with 6 channels in parallel, it may not be 6 channels and is determined by specifications such as the size of the wafer and the inspection time.

  Here, the spatial filter mechanism in the case where the illumination optical system is configured by the optical system shown in FIGS. 44 and 45 has been described. However, even if another illumination system not described here is used, a mechanical space is used. Since the light shielding rate can be improved by using the filter, the diffracted light from the pattern can be efficiently shielded, and the foreign matter detection sensitivity can be improved.

  In addition, when it is desired to further reduce the pitch and width of the spatial filter, the mechanical configuration shown here is insufficient in accuracy. In this case, a variable spatial filter can be made using the method introduced as “micromechanism”.

  The above configuration has the effect of eliminating the trouble of exchanging the spatial filter for each product because the pitch of the spatial filter can be automatically changed by receiving data such as the inter-chip pitch and cell pitch of the product.

  A spatial filter may be created for each product, and the spatial filter may be automatically replaced. An example is shown in FIG. In this method, the three filters of the detectors 1254, 1234, and 1214 shown in FIG. 28 are installed on one substrate and replaced.

1 is a configuration block diagram of a mass production start-up and mass production line foreign matter inspection method and apparatus for a semiconductor manufacturing process according to an embodiment of the present invention. It is a top view of the single wafer type CVD apparatus carrying the foreign material monitor which shows one Example of this invention. It is a block diagram of a foreign material monitor. It is a figure which shows the detection method of a wafer rotation direction detector. It is a figure which shows the coordinate of the product wafer reference | standard for foreign material coordinate management. It is a figure which shows the coordinate of the apparatus reference | standard for foreign material coordinate management. It is a block diagram of a foreign material detection optical system. It is a block diagram of an oblique illumination optical system. It is a figure which shows the detection width of a detection optical system. It is a block diagram of a detector. It is a block diagram of a spatial filter. It is detail drawing of a spatial filter. It is a block diagram of the spatial filter group by the dry plate system corresponding to the product wafer of each process. It is a block diagram of the AND space filter by a dry plate system. It is a block diagram of the foreign material detection optical system by a partial test | inspection. It is a figure which shows the detection area of the foreign material detection optical system by a partial test | inspection. It is a block diagram of the foreign material detection optical system by the micro lens system arrange | positioned at 2 rows. It is a figure which shows the spatial filter detection method by wafer rotation at the time of using a lens array. It is a block diagram of the foreign material detection optical system by white light illumination. It is a figure which shows the foreign material detection performance by white light illumination. It is a block diagram of the foreign material detection optical system by a wafer comparative inspection. It is a system diagram of semiconductor FA using a foreign matter monitor. It is a block diagram which shows one Example of the foreign material inspection apparatus which concerns on this invention. FIG. 24 is a side view of the illumination optical system viewed from the x direction in FIG. 23. It is a side view of the illumination optical system seen from the y direction in FIG. It is a figure which shows one Example of the imaging lens in FIG. It is a figure which shows one Example of the imaging lens in FIG. It is a top view which shows the arrangement | sequence of the optical system shown in FIG. It is a top view which shows a pattern on a wafer. It is a top view which shows a diffraction pattern. It is a figure which shows a refractive index change type | mold lens. It is a top view which shows a spatial filter. It is a figure which shows the example of a foreign material detection. It is a figure which shows the relationship between a detection pixel size and a noise level. It is a block diagram of the foreign material detection optical system using a spatial filter. It is a figure which shows the light intensity distribution in a spatial filter surface. It is a figure which shows the discrimination ratio in a foreign material case optical system. It is a figure which shows the relationship between detection pixel size and a discrimination ratio. It is a figure which shows an illumination area | region and a detection area. It is a performance figure for determining an apparatus specification. It is a figure which shows the apparatus structure of a foreign material detection optical system. It is an example figure which shows the influence by the wafer rotation angle of pattern noise light. It is an example figure which shows the change of the foreign material detection output by wafer stage height. It is a side view of a lighting unit. It is a top view of the diffraction pattern in a spatial filter surface. It is a side view of a lighting unit. It is a top view of the diffraction pattern in a spatial filter surface. It is a block diagram of the foreign material detection optical system by polarization detection. It is an apparatus block diagram of the foreign material detection optical system by polarization detection. It is a figure which shows the positioning and function of this invention. It is a block diagram which shows the Example of a signal processing system. It is a block diagram which shows one Example of this invention using a variable spatial filter. It is a specific block diagram of the variable spatial filter in the case shown in FIG. FIG. 53 is another specific configuration diagram of the variable spatial filter in the case shown in FIG. 52. It is a block diagram which shows another Example of this invention using a variable spatial filter. It is a specific block diagram of the variable spatial filter in the case shown in FIG.

Explanation of symbols

  10 ... Semiconductor manufacturing equipment group, 20 ... Sensing part, 24 ... Vacuum foreign matter monitor, 30 ... Utility group, 40 ... Sampling part, 50 ... Detection part, 60 ... Analysis part, 63 ... STM / STS, 70 ... Corresponding system, 80 ... Mass production start-up of semiconductor manufacturing process and mass production line foreign matter inspection system, 81 ... Online foreign matter inspection system, 82 ... Offline foreign matter inspection system, 101 ... Foreign matter monitor, 111 ... Product wafer, 121 ... Wafer rotation direction detector, 122 ... Foreign matter detection optical system, 123 ... Foreign matter information processing system, 124 ... Device stop function, 128 ... Foreign matter analysis system, 151 ... Oblique illumination optical system, 152 ... Detection optical system, 153 ... Lens array, 154 ... Spatial filter, 155 ... detector, 201 ... spatial filter group, 221 ... and spatial filter, 231 ... micro lens group, 280 ... image processing system, 1110 ... illumination optical system, 1210 ... detection optical system, 1410 ... signal processing system, 1211,1221 ... Imaging lens, 1212,1222 ... space filter

Claims (8)

  In a semiconductor production method in which a substrate is introduced into a semiconductor production line composed of a plurality of semiconductor production processes and a semiconductor element is formed on the substrate, the processing is performed in a predetermined process among the plurality of semiconductor production processes of the semiconductor production line. A plurality of detectors are used to inspect a plurality of regions of the substrate to detect foreign matter generated on the substrate in real time, and the semiconductor manufacturing line is based on information on the foreign matter detected in real time. A method for manufacturing a semiconductor device, characterized in that:   2. The method of manufacturing a semiconductor device according to claim 1, wherein a plurality of regions on the substrate are simultaneously inspected by the plurality of detectors.   A substrate is processed in a predetermined step among a plurality of processing steps of a semiconductor manufacturing line, and a plurality of regions of the processed substrate are irradiated with light, and reflected light from the substrate due to the irradiation is irradiated with the plurality of Detecting using a plurality of detectors corresponding to each of the regions, processing the signals obtained by detecting the reflected light with the plurality of detectors in parallel, the foreign matter generated on the substrate in real time A method of manufacturing a semiconductor device, comprising: inspecting and monitoring the semiconductor manufacturing line based on information on foreign matters inspected in real time.   In a semiconductor production method in which a substrate is introduced into a semiconductor production line composed of a plurality of semiconductor production steps and a semiconductor element is formed on the substrate, the processing is performed in a first step among the plurality of semiconductor production steps of the semiconductor production line. Inspecting the applied substrate to detect foreign matter generated on the substrate, processing the inspected substrate in a second step, inspecting the substrate processed in the second step, and And the information obtained by inspecting the substrate processed in the second step and the information obtained by inspecting the substrate processed in the second step. A method for manufacturing a semiconductor device, comprising: monitoring a semiconductor manufacturing line.   In a semiconductor production method in which a substrate is introduced into a semiconductor production line composed of a plurality of semiconductor production processes and a semiconductor element is formed on the substrate, the processing is performed in a predetermined process among the plurality of semiconductor production processes of the semiconductor production line. Then, light is emitted to the substrate on which the pattern portion having a partly repeated pattern is formed on almost the entire surface, and reflected light from the repeated pattern portion by the irradiated light is detected on almost the entire surface of the substrate, and the detection is performed. By processing the signal thus obtained, the foreign matter generated in the region where the repetitive pattern is formed on the substrate is inspected in real time, and the semiconductor manufacturing is performed based on the information of the foreign matter obtained by the real time inspection. A method of manufacturing a semiconductor device, comprising monitoring a line.   In a semiconductor production method in which a substrate is introduced into a semiconductor production line composed of a plurality of semiconductor production processes and a semiconductor element is formed on the substrate, the processing is performed in a predetermined process among the plurality of semiconductor production processes of the semiconductor production line. A region on which the repetitive pattern is formed on the substrate by irradiating the substrate on which at least a part of the repetitive pattern is formed with light and detecting the reflected light from the substrate through the spatial filter. A method for manufacturing a semiconductor device comprising: detecting foreign matter generated in real time in real time, and monitoring the semiconductor production line based on information on the foreign matter generated in a region where the repetitive pattern detected in real time is formed .   2. The apparatus according to claim 1, wherein the semiconductor manufacturing line is monitored to detect the occurrence of foreign matter abnormality, and an alarm or the like is notified, or the main body of the processing apparatus causing the foreign matter abnormality is stopped. A method for manufacturing a semiconductor device according to any one of claims 6 to 10.   Detecting light having a plurality of pixels reflected from the substrate by irradiating light onto a substrate on which a pattern is formed by processing in a predetermined process among a plurality of semiconductor manufacturing processes of a semiconductor manufacturing line A method of monitoring the semiconductor manufacturing line by detecting a defect on the substrate in real time by detecting with a detector, the information on the size of the defect to be detected on the substrate, the defect and the pattern A method of manufacturing a semiconductor device, wherein a defect is detected by switching a pixel size corresponding to a size of an area in which the substrate is imaged in each pixel of the detector according to information on the discrimination ratio.

Images