Inspection substrate, its regeneration method, and substrate processing apparatus

Abstract

An inspection substrate comprises a plate-form substrate, an imaging element provided to at least part of the surface of the substrate, an optically transparent protective layer formed on the surface of the imaging element, and an output unit that outputs the output of the imaging element to outside of the inspection substrate. On the basis of the output of the imaging element, which varies due to light emitted from a light source being blocked by contaminants adhering to the protective layer, it is possible to detect the state of adherence of the contaminants to the protective layer.

Description

[Technical field]

[0001] The present disclosure relates to an inspection substrate, a regeneration method thereof, and a substrate processing apparatus. [Background technology]

[0002] In the manufacture of semiconductor devices, a substrate processing system including a transport unit and a processing unit is used to perform various processes, such as chemical processing, film formation processing, heat processing, and the like, on a substrate to be processed (e.g., a semiconductor wafer). Patent Document 1 discloses a coating and developing apparatus for coating a substrate with resist and performing development processing after exposure, as a substrate processing system. In this coating and developing apparatus, a substrate for temperature monitoring, called a wireless wafer, is used. The wireless wafer has a plurality of temperature sensors and a controller, and can transmit the temperature detected by the temperature sensor by wireless communication. When the wireless wafer is placed on the heating plate and when the wireless wafer is transported to the heating plate, which are performed before and after the placement, the change in the actual temperature of the wireless wafer over time is measured. The control parameters of the heating plate can be appropriately adjusted based on the measurement results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-08489 A Summary of the Invention

[0004] The present disclosure provides a technique capable of detecting the state of adhesion of contaminants to the surface of an inspection substrate, which is a substrate for inspection, during processing or transportation of the inspection substrate.

[0005] One embodiment of the inspection board comprises a plate-shaped base material, an imaging element provided on at least a portion of the surface of the base material, a light-transmitting protective layer formed on the surface of the imaging element, and an output section that outputs the output of the imaging element to the outside of the inspection board, and is capable of detecting the state of adhesion of the contaminants to the protective layer based on the output of the imaging element that changes when light irradiated from a light source is blocked by contaminants adhered to the protective layer.

[0006] According to the present disclosure, it is possible to detect the state of adhesion of contaminants to the surface of an inspection substrate during processing or transportation of the inspection substrate. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view of a substrate processing system according to an embodiment of the substrate processing apparatus. [Diagram 2] FIG. 2 is a schematic vertical cross-sectional view showing the structure of a doctor wafer according to one embodiment. [Diagram 3] FIG. 2 is a schematic plan view showing the arrangement of electrodes on a doctor wafer according to one embodiment. [Figure 4] 2 is a schematic vertical cross-sectional view showing an example of the configuration of a processing unit included in the substrate processing system. [Diagram 5] 11 is a schematic vertical sectional view showing another example of the configuration of a processing unit included in the substrate processing system. FIG. [Figure 6] 1 is a schematic vertical cross-sectional view showing an example of a configuration of a substrate transport device included in a substrate processing system. [Figure 7] 11 is a graph showing an example of the change over time in particle level from the start of treatment liquid from a nozzle. [Figure 8] 3 is a piping diagram showing an example of the configuration of a processing liquid supply system that supplies a processing liquid to a nozzle. FIG. [Figure 9] 13 is a flowchart illustrating a specific example 4 of the operation of the doctor wafer. [Figure 10] FIG. 13 is a diagram showing an example of particle distribution related to Example 5. [Figure 11]FIG. 13 is a diagram showing another example of particle distribution related to the fifth specific example. [Figure 12] FIG. 13 is a diagram showing yet another example of particle distribution related to the specific example 5. [Figure 13] FIG. 13 is a diagram showing an example of particle distribution related to Example 6. [Figure 14] 1 is a schematic cross-sectional view illustrating detection of particle size using a doctor wafer. [Figure 15] FIG. 11 is a distribution diagram for explaining detection of particle sizes using a doctor wafer. [Figure 16] 10A to 10C are schematic cross-sectional views illustrating a case where a scratch is formed on a doctor wafer. [Figure 17] FIG. 11 is a schematic cross-sectional view showing another configuration example of the doctor wafer. [Figure 18] FIG. 11 is a schematic cross-sectional view showing another configuration example of the doctor wafer. [Figure 19] FIG. 11 is a schematic cross-sectional view showing another configuration example of the doctor wafer. [Figure 20] FIG. 11 is a schematic cross-sectional view showing another configuration example of the doctor wafer. [Figure 21] FIG. 13 is a schematic plan view showing another configuration example of the doctor wafer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of a substrate processing apparatus will be described with reference to the accompanying drawings.

[0009] 1 is a diagram showing a schematic configuration of a substrate processing system according to the present embodiment. In the following, to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are defined, and the positive direction of the Z-axis is defined as the vertical upward direction.

[0010] 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0011] The carry-in / out station 2 includes a carrier placement section 11 and a transport section 12. On the carrier placement section 11, a plurality of carriers C are placed, each of which accommodates a plurality of substrates, in this embodiment, semiconductor wafers (hereinafter referred to as wafers W), in a horizontal state.

[0012] The transfer section 12 is provided adjacent to the carrier placement section 11, and includes therein a substrate transfer device 13 (transfer mechanism) and a delivery section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds a wafer W (substrate). The substrate transfer device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the carrier C and the delivery section 14 using the wafer holding mechanism.

[0013] The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15 and a plurality of processing units 16. The plurality of processing units 16 are provided side by side on both sides of the transport section 15.

[0014] The transfer section 15 includes a substrate transfer device 17 (transfer mechanism) therein. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 17 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the delivery section 14 and the processing unit 16 using the wafer holding mechanism.

[0015] The processing unit 16 performs a predetermined substrate processing on the wafer W transferred by the substrate transfer device 17 .

[0016] The substrate processing system 1 includes a notch aligner 90, i.e., a positioning device, that aligns the wafer in the circumferential direction. The notch aligner 90 can be provided, for example, in the transfer section 12 of the load / unload station 2 (for example, in the transfer space of the substrate transfer device 13 or in the delivery section 14). Instead of the notch aligner 90, a device that positions the wafer by detecting the orientation flat may be used as the positioning device.

[0017] The substrate processing system 1 may include a doctor wafer storage unit 92 for storing a doctor wafer (test substrate) DW, which will be described later. The doctor wafer storage unit 92 may be provided at any position in the substrate processing system 1 as long as the substrate transport device 13 or the substrate transport device 17 can access the doctor wafer storage unit 92.

[0018] The substrate processing system 1 also includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading out and executing the programs stored in the storage unit 19.

[0019] Such a program may be recorded in a computer-readable storage medium and installed from that storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0020] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 in the loading / unloading station 2 removes the wafer W from the carrier C placed on the carrier placement section 11, and places the removed wafer W on the transfer section 14. The wafer W placed on the transfer section 14 is then removed from the transfer section 14 by the substrate transfer device 17 in the processing station 3, and carried into the processing unit 16.

[0021] The wafer W carried into the processing unit 16 is processed by the processing unit 16, and then carried out of the processing unit 16 by the substrate transfer device 17 and placed on the transfer section 14. Then, the processed wafer W placed on the transfer section 14 is returned to the carrier C of the carrier placement section 11 by the substrate transfer device 13.

[0022] Contaminants, particularly particles, adhere to the wafer W at various locations in the above-mentioned substrate processing system 1. In order to analyze the cause of the particles adhering to the wafer W, the following doctor wafer DW (inspection substrate) is transported and processed in the substrate processing system 1.

[0023] As will be apparent from the following description, the doctor wafer DW can detect a wide variety of contaminants other than particles, such as water marks and surface defects such as scratches. In the following description, particles will be used as an example to explain the most typical detection target.

[0024] The configuration of the doctor wafer DW will be described below. One configuration example of the doctor wafer DW is shown in Figure 2. The doctor wafer DW includes a wiring layer 102, a light receiving layer 104, and a protective layer 106, which are sequentially stacked on a substrate 100 (disk-shaped base material) made of a semiconductor wafer.

[0025] The wiring layer 102 and the light receiving layer 104 can be formed using a known technique for forming an imaging element (e.g., a back-illuminated CMOS). The doctor wafer DW can also be said to be an imaging element of the same size as the wafer W. The wiring layer 102 and the light receiving layer 104 may be configured to correspond to a CCD imaging element.

[0026] The light receiving layer 104 has a large number (plurality) of photodiodes arranged in a matrix. Since there is no need to distinguish colors in the doctor wafer DW, no color filters are provided on the photodiodes. Therefore, the light receiving layer 104 of the doctor wafer DW has a detection resolution that corresponds exactly to the number of photodiodes (number of pixels). Each photodiode is hereinafter referred to as a pixel 105. In a non-limiting exemplary embodiment, the size of each pixel 105 is 5 nm.

[0027] The protective layer 106 is preferably formed from a material that has sufficient optical transparency, is not easily attacked by the processing fluid to which the doctor wafer DW is exposed, and has surface properties (e.g., hydrophobicity) similar to those of the wafer W (product wafer). In the illustrated embodiment, the protective layer 106 is formed from a pixel protection damper 106a provided on the light receiving layer 104 and transparent glass (SiOx) 106b. The surface properties (e.g., hydrophobicity) of the transparent glass are similar to those of the wafer W.

[0028] The material constituting the protective layer 106 (particularly its surface) can be changed depending on the processing fluid to which the doctor wafer DW is exposed. In order to make the surface characteristics (e.g., hydrophobicity) of the protective layer 106 closer to the surface characteristics of the substrate to be processed, a light-transmitting coating having desired characteristics (e.g., a thin transparent PFA or PTFA film) may be applied. In order to make the protective layer 106 resistant to various processing liquids, a light-transmitting coating may be provided on the outermost surface of the protective layer 106. As the light-transmitting coating, SiN, SiOx, etc. can be used when acid resistance is desired, SiOx, etc. when alkali resistance is desired, and SiOx, etc. can be used when oil resistance is desired.

[0029] 3, a plurality of electrodes 108 (power receiving parts) are provided on the periphery of the doctor wafer DW. The electrodes 108 function as power receiving electrodes for receiving power for operating the imaging elements (102+104), as input electrodes for receiving command signals from an external device (e.g., a signal processing device) that instruct the imaging elements to read pixel data, and as output electrodes for outputting pixel data output from the doctor wafer DW to an external device (e.g., a signal processing device).

[0030] Two or more different functions among the above functions may be assigned to the same electrode 108 (electrode member). Each electrode 108 (electrode member) may be assigned one different function. When the image sensor is a back-illuminated CMOS, the power for operating the image sensor is exemplified by a supply electrode to a pixel amplifier.

[0031] The electrode 108 is provided at a position where it can be in electrical contact with various components that come into contact with the wafer W in the substrate processing system 1, such as the gripping claws of a mechanical spin chuck (described later) and the holding claws of a transfer arm (described later). The electrode 108 can be provided so as to be exposed, for example, on the surface (peripheral side surface) of the apex of the doctor wafer DW, the bevel portion, or a flat portion in the vicinity thereof.

[0032] The electrodes 108 are electrically connected to the wiring layer 102. It is assumed that the gripping claws of the mechanical spin chuck are positioned so as to come into contact with the electrodes 108 shown in black in Fig. 3. It is assumed that the holding claws of the transport arm are not necessarily positioned so as to come into contact with the electrodes 108 shown in black, but are positioned so as to come into contact with the electrodes 108 shown in white, for example. In this case, a connection line 110 can be provided to connect the electrodes 108 that play the same role (for example, electrodes that transmit and receive power, command signals, and pixel data (image signals) to and from a specific area of ​​the doctor wafer DW).

[0033] When a particle adheres to the surface of the protective layer 106 of the doctor wafer DW, the illumination light irradiated to the doctor wafer DW is blocked by the particle. In other words, the output of the pixel 105 below the particle becomes smaller. By utilizing this, the distribution of particles on the doctor wafer DW can be detected.

[0034] In addition, by reading out images (pixel data) from the doctor wafer DW at a sufficiently high frame rate (e.g., hundreds to thousands of fps), it is also possible to grasp the movement of particles over time, for example, during liquid processing. In this case, since the amount of data becomes enormous, data may be obtained at short time intervals (corresponding to the above-mentioned high frame rate) only from pixels located on two mutually perpendicular straight lines (a straight line extending in the X direction and a straight line extending in the Y direction) extending along the diameter of the doctor wafer DW. The movement of particles over time may be grasped by forming a Signal-Time 3D map based on this data.

[0035] In order to detect particles on the doctor wafer DW, it is necessary to irradiate the doctor wafer DW with light. For this reason, lighting devices can be provided at various locations in the substrate processing system 1. The location of the lighting device is arbitrary, but it is preferable to provide it in a location where particles are particularly likely to be generated. Examples of locations where particles are likely to be generated include inside the processing unit 16 and near the delivery section 14 where the wafer W is delivered.

[0036] Next, a description will be given of the configuration of the processing unit 16 equipped with the illumination device. As shown in FIG. 4, the processing unit 16 includes a chamber 20, a spin chuck (substrate holding mechanism) 30, a processing fluid supply part 40, and a collection cup 50.

[0037] The chamber 20 accommodates the spin chuck 30, a processing fluid supply unit 40, and a collection cup 50. A fan filter unit (FFU) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a downflow within the chamber 20.

[0038] The spin chuck 30 is configured as a mechanical chuck. The spin chuck 30 has a substrate holding portion 31. The substrate holding portion 31 has a disk-shaped support plate 32 and a plurality of gripping claws 33 provided on the periphery of the support plate 32, preferably at equal intervals in the circumferential direction. At least one of the gripping claws 33 is movable. The spin chuck 30 holds the wafer W in a horizontal position by engaging the gripping claws 33 with the periphery of the wafer W. The support plate 32 is rotated by an electric motor (drive unit) 34, thereby rotating the wafer W around a vertical axis.

[0039] The gripping jaws 33 are provided with electrodes 35 that can be in electrical contact with the electrodes 108 of the doctor wafer DW. The notch N (see FIG. 3) of the doctor wafer DW has a predetermined positional relationship with the electrodes 108 of the doctor wafer DW. Since the doctor wafer DW is positioned in the circumferential direction by the notch aligner 90, each electrode 108 of the doctor wafer DW always comes into contact with a predetermined electrode 35 of the gripping jaws 33 when held by the spin chuck 30.

[0040] Connected to the electrode 35 are a power supply 36 that supplies the power necessary to operate the doctor wafer DW (e.g., power to operate a pixel amplifier), and a signal processing device (transmitter / receiver and calculation unit) 37 that outputs a command signal instructing the doctor wafer DW to read pixel data and processes the pixel data signal output from the doctor wafer DW.

[0041] The processing fluid supply unit 40 has one or more nozzles 41 that discharge processing fluid. The nozzle 41 is supported at the tip of a nozzle arm 42 that can rotate around a vertical axis, and can move at least between a position directly above the center of the wafer W and a position directly above the peripheral edge of the wafer W. A processing fluid supply mechanism 43 that supplies processing fluid (processing liquid, processing gas) to the nozzle 41 is connected to each nozzle 41. A plurality of types of processing fluid may be supplied from each nozzle 41, in which case a plurality of processing fluid supply mechanisms 43 are connected to one nozzle 41. The number of nozzles 41 and the number of nozzle arms 42 provided in one processing unit 16 are arbitrary.

[0042] The substrate holding portion 31 of the spin chuck 30 is surrounded by a collection cup 50. The collection cup 50 collects the processing liquid scattered from the wafer W. A drainage port 51 and an exhaust port 52 are formed at the bottom of the collection cup 50. The processing liquid is discharged from the drainage port 51 to the outside of the collection cup 50. The exhaust port 52 is constantly sucked during normal operation of the processing unit 16, so that the atmosphere in the space above the wafer W (e.g., clean air supplied from the FFU 21 into the chamber 20) is sucked into the collection cup 50. The airflow generated by this prevents the processing liquid scattered from the wafer W from adhering again to the wafer W.

[0043] An illumination device 45 is provided on the lower surface of the nozzle arm 42. The illumination device 45 is disposed on the nozzle arm 42 so that when the nozzle 41 is located directly above the center of the wafer W, the illumination device 45 can continuously (without interruption) illuminate the section from the center to the periphery of the surface of the wafer W. When the illumination device 45 is turned on when the nozzle 41 is located directly above the center of the doctor wafer DW, a linear or elongated strip-shaped illumination section is formed on the surface of the doctor wafer DW, which extends continuously in the radial direction from the center to the periphery.

[0044] FIG. 5 shows a modified example of the processing unit 16. In this modified example, an illumination device 46 is provided at the location where the FFU 21 was provided in the example of FIG. 4. The illumination device 46 can be configured from a disk-shaped member having a diameter at least larger than the diameter of the wafer W. The illumination device 46 can be configured to include a light emitting unit 46a and a polarizing filter 46b made of graphene or the like. In this case, the surface of the wafer W can be irradiated with parallel light (light that travels substantially only in a direction perpendicular to the surface of the wafer W), and the particle inspection accuracy can be improved even if the wafer W is irradiated with light from a relatively distant position. The illumination device 45 shown in FIG. 4 may have the same configuration as the illumination device 46. In the modified example of FIG. 5, an outlet of the side flow type FFU 21 can be provided on the side wall of the chamber 20. Other than the above-mentioned points, the configuration of the processing unit 16 in FIG. 5 may be the same as that of the processing unit in FIG. 4.

[0045] Next, the configuration of substrate transfer device 17 (particularly the configuration in the vicinity of the substrate holder) will be described with reference to Fig. 6. Substrate transfer device 17 has a moving base 171 that is capable of translational movement in the X direction (horizontal direction) and the Z direction (vertical direction) and is rotatable about a vertical axis. A fork 172 (substrate holder) that can advance and retreat horizontally is provided on moving base 171.

[0046] 6 illustrates the fork 172 in the retracted position. The fork 172 is located at the forward position when transferring the wafer W between a wafer holding structure such as the spin chuck 30 of the processing unit 16 and the stage of the transfer section 14, and is located at the retracted position when transferring the wafer W between the wafer holding structures.

[0047] The fork 172 is provided with a plurality of holding claws 173, at least one of which is movable. By moving the movable holding claw 173, the fork 172 can hold and release the wafer W (doctor wafer DW). The holding claw 173 is provided with an electrode 175 that can be electrically contacted with the electrode 108 of the doctor wafer DW. When the doctor wafer DW is properly positioned, each electrode 108 always comes into contact with the electrode 175 of a predetermined holding claw 173 when held by the fork 172.

[0048] The electrode 175 is connected to a power supply 177 that supplies the power necessary to operate the doctor wafer DW, and a signal processing device 179 (or the signal processing device 37 mentioned above) that outputs a command signal instructing the doctor wafer DW to read pixel data and processes the pixel data (image signal) output from the doctor wafer DW.

[0049] The movable base 171 is provided with an illumination device 174. The illumination device 174 is provided so as to irradiate the entire surface of the doctor wafer DW held by the forks 172 located at the retreated position with light. The configuration of the illumination device 174 may be similar to that of the illumination devices 45, 46 provided in the processing unit 16.

[0050] The lighting device 174 may be a strip-shaped device (preferably with a length equal to or greater than the diameter of the doctor wafer DW) extending in a direction perpendicular to the direction in which the forks 172 advance and retreat. In this case, it is sufficient that the entire area of ​​the doctor wafer DW crosses the strip-shaped irradiation area of ​​the lighting device 174 as the forks 172 advance and retreat.

[0051] 5, a wafer loading / unloading opening 22 with a shutter is provided on one of the side walls of the chamber 20 of the processing unit 16 (the same applies to the configuration in FIG. 4, but is not shown in FIG. 4). A rectangular lighting device 47 having a length equal to or greater than the diameter of the wafer W may be provided on the ceiling of the wafer loading / unloading opening 22. In this case, when the fork 172 holding the doctor wafer DW passes under the lighting device 47, the doctor wafer DW can be inspected.

[0052] Units / apparatus other than the processing unit 16 shown in Figures 4 and 5 and the substrate transport device 17 shown in Figure 6 can also be provided with electrodes that can be in electrical contact with the electrode 108 of the doctor wafer DW, as well as lighting devices that irradiate light onto the doctor wafer DW in such units / apparatus. In this case, too, the electrodes can be connected to a power source that supplies the power required to operate the doctor wafer DW, and a signal processing device that outputs a command signal to instruct the doctor wafer DW to read pixel data and processes the pixel data (image signal) output from the doctor wafer DW.

[0053] The lighting device may also be provided on the ceiling of a room forming the wafer transport space, on the ceiling of the delivery section 14, and the like.

[0054] Next, specific examples of investigating particle generation status and / or analyzing the cause of generation using the doctor wafer DW will be described. In each of the following specific examples, the amount of particles present on the surface of the doctor wafer DW is measured based on the signal output from each pixel 105 of the doctor wafer DW.

[0055] <Example 1> A carrier C containing a doctor wafer DW is placed on the carrier placement section 11 (Step 1). The forks (substrate holders) of the substrate transport device 13 in the loading / unloading station 2 enter the carrier C and remove the doctor wafer DW from the carrier C (Step 2). The forks of the substrate transport device 13 enter the delivery section 14 and place the doctor wafer DW on the delivery section 14 (Step 3).

[0056] If the notch aligner 90 is in the transport section 12, the doctor wafer DW is positioned between step 2 and step 3. By performing the positioning, the electrode 175 of the fork 172 of the substrate transport device 17 (13) and the electrode 35 of the spin chuck 30 can be reliably contacted with the electrode 108 of the doctor wafer DW. If the positioned doctor wafer DW is stored in the carrier C, the positioning operation can be omitted. If the doctor wafer storage section 92 is in the transport section 12, the series of steps may start with a step of transporting the positioned doctor wafer DW stored in the doctor wafer storage section 92 from the doctor wafer storage section 92 to the delivery section 14.

[0057] After step 3, the forks of the substrate transport device 17 of the processing station 3 enter the transfer section 14 and remove the doctor wafer DW from the transfer section 14 (step 4). The forks of the substrate transport device 17 enter the processing unit 16 and transfer the doctor wafer DW to the spin chuck 30 in the processing unit 16 (step 5). The doctor wafer DW is subjected to liquid processing in the processing unit 16 (step 6). After the liquid processing is completed, the forks of the substrate transport device 17 enter the processing unit 16 and remove the doctor wafer DW from the processing unit 16 (step 7). The forks of the substrate transport device 17 enter the transfer section 14 and place the doctor wafer DW on the transfer section 14 (step 8). The forks of the substrate transport device 13 enter the transfer section 14 and remove the doctor wafer DW from the transfer section 14 (step 9). The forks of the substrate transport device 13 enter the original carrier C and store the doctor wafer DW in the carrier C (step 10).

[0058] During the above steps 1 to 10, the change in the adhesion state of particles on the doctor wafer DW can be grasped based on the output signal of the doctor wafer DW. The doctor wafer DW can output a signal to the outside while the electrode 108 of the doctor wafer DW is in contact with an external electrode (for example, the electrode 35 of the gripping jaws 33 of the spin chuck 30 of the processing unit 16, or the electrode 175 of the holding jaws 173 of the fork 172 of the substrate transport device 17). If data when the electrode 108 of the doctor wafer DW is not in contact with such an external electrode is also required, a data buffer (memory unit) may be provided on the doctor wafer DW as described later, or a wireless output unit (antenna) may be provided on the doctor wafer DW (described later).

[0059] It is possible to identify steps where a large number of particles are generated by investigating the change in the amount of particles (here, for example, the total amount of particles) on the doctor wafer DW from step 1 to step 10. By focusing on taking measures against particles in these identified steps, it is possible to efficiently reduce particles.

[0060] When the wafer W is being processed without any problems, the doctor wafer DW may be used to periodically obtain data on the transition of the particle amount as described above. By comparing the data on the transition of the particle amount obtained at a certain time with the data on the transition of the particle amount obtained earlier, it is possible to predict the possibility of a problem related to particles occurring. For example, if the particle amount increases in steps 3, 4, 8, 9, etc., in which the doctor wafer DW is inserted into and removed from the transfer unit 14, it is estimated that a particle-causing substance is attached to the transfer unit 14. In this case, particle contamination of the wafer W can be prevented in advance by cleaning the transfer unit 14.

[0061] A series of steps excluding only step 6 (liquid processing) from step 1 to step 10 above may be performed (steps 5 and 7 related to loading / unloading to / from processing unit 16 may be performed) to detect particles generated during transfer. By identifying the coordinates of the location where particles have increased during transfer, it can be assumed that a component of the substrate processing system in the vicinity of the coordinates is causing the generation of particles, and measures against particles can be easily taken.

[0062] Steps 1 to 10 may be executed while changing only the processing unit 16 that is the target of steps 5 to 7. In this case, it is possible to identify the processing unit 16 that is likely to generate particles.

[0063] <Example 2> The above-mentioned step 6 can be further divided to investigate the transition of the particle amount. After the above-mentioned step 5 is completed (i.e., when the doctor wafer DW is held on the spin chuck 30), the doctor wafer DW is subjected to liquid processing in the processing unit 16 (step 6). Step 6 is composed of a plurality of steps (sub-steps). First, the spin chuck 30 is rotated to rotate the doctor wafer DW, and a pre-wet liquid (e.g., DIW) is supplied to the doctor wafer DW from the nozzle 41 (step 61). Next, the chemical liquid A is supplied to the doctor wafer DW (step 62), then the rinsing liquid is supplied to the doctor wafer DW (step 63), then the chemical liquid B is supplied to the doctor wafer DW (step 64), then the rinsing liquid is supplied to the doctor wafer DW (step 65), then IPA is supplied to the doctor wafer DW (step 66), and then the doctor wafer DW is shaken off and dried (step 67).

[0064] By investigating the change in the amount of particles (here, for example, the total amount of particles) on the doctor wafer DW from step 61 to step 67, it is possible to identify the step where a large number of particles are generated. By focusing on taking measures against particles in this identified step, it is possible to efficiently reduce particles. For example, if the amount of particles is not sufficiently low after step 65, it is presumed that there is some problem with the rinsing step. In this case, it is sufficient to check whether there is a problem with the conditions of the rinsing step and whether there is any contamination, etc., of the components of the processing unit 16 related to the rinsing step.

[0065] In this specific example 2, similarly to specific example 1, the doctor wafer DW may be used to periodically acquire data on the transition of the particle amount as described above while the wafer W is being processed without any problems. By comparing the data on the transition of the particle amount acquired at a certain time with the data on the transition of the particle amount acquired earlier, it is possible to predict the possibility of a problem related to particles occurring.

[0066] <Example 3> The contamination status of a certain nozzle 41 and the processing fluid supply mechanism 43 connected thereto can be detected by using the doctor wafer DW. In this case, the nozzle 41 supplies the processing liquid to the vicinity of the center of the doctor wafer DW rotated by the spin chuck, and the particle level detection by the doctor wafer DW is performed only near the center of the doctor wafer DW. As shown in the graph of Fig. 7, the change over time in the particle amount detection value by the doctor wafer DW (more specifically, the increase in the particle amount from before the start of processing) is detected from the point when the nozzle 41 starts to eject the processing liquid.

[0067] The configuration of one nozzle 41 and the processing fluid supply mechanism 43 connected thereto is shown generally in Fig. 8. Branch supply pipes 432 branch off from a main supply pipe 431 for the processing liquid (e.g., a circulation pipe connected to a processing liquid storage tank) toward each processing unit 16. In the branch supply pipe 432, a flow meter 433, a constant pressure valve 434 functioning as a flow control valve, and an on-off valve 435 are interposed in this order from the upstream side. The nozzle 41 is connected to the downstream end of the branch supply pipe 432.

[0068] 7, if the amount of particles is high immediately after the nozzle 41 starts to discharge the processing liquid and then decreases, it is highly likely that the vicinity of the discharge port of the nozzle 41 is contaminated. In such a case, a possible solution is to change the process recipe so that a dummy dispense of about 3 seconds is performed before the nozzle 41 starts to discharge the processing liquid.

[0069] Also, for example, as shown by the dashed line in the graph of Figure 7, suppose that the amount of particles is low immediately after the nozzle 41 starts to discharge the processing liquid, but increases at a point T (sec) after the start of discharge (approximately 5 sec in the graph) and then decreases. In this case, it can be seen that there is a high possibility that a piping system component located a distance D (cm) upstream from the tip of the nozzle 41 is contaminated. Let V (ml / sec) be the discharge flow rate of the processing liquid from the nozzle 41 and A (cm) be the cross-sectional area of ​​the piping. 2 ), L can be approximately calculated using the following formula: D=VT / A

[0070] For example, if the member located at a distance D from the tip of the nozzle 41 is the on-off valve 435, it is estimated that there is a high possibility that the on-off valve 435 is contaminated or that dust is being generated by the opening and closing operation of the on-off valve 435. In this case, the on-off valve 435 can be washed or replaced with a new one. If the on-off valve 435 is contaminated, it may be possible to remove contaminants from inside the branch supply pipe 432 (including the liquid-contacting surface of the on-off valve 435) by performing a dummy dispense from the nozzle 41, preferably at a relatively large flow rate and for a relatively long period of time.

[0071] If the distance D is greater than the distance from the tip of the nozzle 41 to the upstream end of the branch supply pipe 432, there is a high possibility that the processing liquid flowing through the main supply pipe 431 is contaminated. In this case, the processing in all the processing units 16 may be temporarily stopped, and the degree of contamination of the processing liquid flowing through the main supply pipe 431 may be confirmed.

[0072] <Example 4> Next, a determination as to whether or not a wafer W can be processed in the processing unit 16 and a corresponding action, which is performed, for example, periodically by using the doctor wafer DW, will be described with reference to the flowchart of FIG.

[0073] First, it is determined whether the surface of the doctor wafer DW (denoted as "DrW" in the flow chart of FIG. 9) is sufficiently clean to perform an inspection (step 201). This determination can be made, for example, by holding the doctor wafer DW by the substrate transfer device 17 or the spin chuck 30 of the processing unit 16 and reading out image data from the doctor wafer DW. The determination can be made, for example, by determining whether the particles present on the surface of the doctor wafer DW are equal to or less than a reference value for the total amount of particles determined for each particle size.

[0074] If the result of the judgment is negative (NG), that is, if it is judged that the surface of the doctor wafer DW is contaminated, the inspection is stopped for the time being (step 202). In this case, the surface of the contaminated doctor wafer DW can be subjected to two-fluid cleaning or scrub cleaning, or a regeneration process of the surface of the doctor wafer DW can be performed (described in detail later). The contaminated doctor wafer DW can be replaced with another clean doctor wafer DW, and the process can proceed to step 203.

[0075] If the result of the judgment is OK, that is, if it is judged that the surface of the doctor wafer DW is sufficiently clean, a series of processes are performed on the doctor wafer DW using the process recipe of the wafer W. After the processes are completed, the amount of particles on the surface of the doctor wafer DW is measured (step 203). This measurement can be performed, for example, while the doctor wafer DW continues to be held by the spin chuck 30 of the processing unit 16.

[0076] Then, the amount of particles before and after the liquid processing is compared (step 204), and if the increase in the amount of particles is equal to or less than a predetermined threshold, the result is OK, and processing of the wafer W by the processing unit 16 is permitted (step 205). With the above, the inspection is completed.

[0077] If the increase in the amount of particles exceeds a predetermined threshold, the judgment result is NG. Then, the flow proceeds to step 206. If the judgment is NG for the second time, processing of the wafer W by that processing unit 16 is prohibited (step 207) (described in detail later).

[0078] If it is determined in step 206 that the result is a first NG judgment, an alarm is generated by a user interface such as a display or an alarm generator, and processing of the wafer W by the processing unit 16 being inspected is temporarily prohibited (step 208). If the inspection using the doctor wafer DW is being performed in parallel with normal processing of the wafer W, the processing schedule may be changed to exclude that processing unit 16.

[0079] Next, the data of the change over time of the particles measured using the doctor wafer DW is compared with the processing log of the processing unit 16 to estimate the cause of the generation of the particles. The processing log is data showing the relationship between time and the executed procedure, and is a collection of data in a format such as "13:56:25: Open the opening / closing valve of the processing fluid supply mechanism 43 (start of discharging the chemical solution A from the nozzle 41)". Specifically, for example, the cause of the generation of the particles is estimated by making a judgment as described in the above-mentioned specific example 2 and specific example 3 (step 209).

[0080] Next, it is determined whether the cause of particle generation is (A) contamination of the processing fluid supply mechanism 43 (liquid supply system) or (B) something else (step 210). For an example of (A) contamination of the liquid supply system, see the above-mentioned specific example 2 and specific example 3.

[0081] When the cause of particle generation is (A) dirt in the piping (including valves, flowmeters, etc.) of the processing fluid supply mechanism 43 (liquid supply system), for example, cleaning (flushing) of the liquid supply system is performed. Specifically, for example, a dummy spray is performed from the nozzle 41 using the processing fluid supply mechanism 43 for a predetermined time to wash away dirt in the piping (step 211).

[0082] (B) Examples of other causes include dirt on the inner wall of the chamber 20 or dirt on the collection cup 50. In the case of dirt on the chamber 20 or the collection cup 50, particles tend to concentrate on the peripheral portion of the doctor wafer DW, and based on this, it can be determined that the cause is (B).

[0083] An example of determining whether the cause is (A) or (B) will be described below. If a large number of particles are detected at the location where the processing liquid discharged from the nozzle 41 lands on the doctor wafer DW (for example, the center of the doctor wafer DW) during processing, it can be determined that there is a high possibility that the cause of particle generation is within the processing fluid supply mechanism 43 (in the flow path of the processing liquid) (i.e., the cause is (A)). On the other hand, if the collection cup 50 is highly contaminated, the processing liquid scattered from the doctor wafer DW collides with the collection cup 50, scatters together with the contaminants, and reattaches to the peripheral portion of the doctor wafer DW. Therefore, if a large number of particles are detected on the peripheral portion of the doctor wafer DW during processing, it can be determined that there is a high possibility that the cause is (B). Note that if a large number of particles are detected on the peripheral portion of the doctor wafer DW during processing while the processing liquid is being applied to the center of the doctor wafer DW, it can be seen that there is a higher possibility that the cause is (B).

[0084] If it is determined that the amount of particles has increased due to dirt falling off of the chamber 20 or collection cup 50, cleaning liquid is sprayed from a cup inner wall cleaning nozzle or a chamber inner wall cleaning nozzle (not shown) to clean the inner walls of the cup and the chamber (step 212).

[0085] After step 211 or step 212 is executed, the flow returns to step 201. If the determination result in step 204 is then OK, processing of the wafer W in that processing unit 16 is permitted.

[0086] If the determination result in step 204 is NG again, the determination result in step 206 is YES (Y), and therefore the processing of wafers W in that processing unit 16 is prohibited. In this case, an alarm is generated by a user interface such as a display or an alarm generator, prompting an operator to clean or overhaul that processing unit 16.

[0087] In the above specific example, in steps 211 and 212, cleaning operations that can be performed automatically are performed, but the present invention is not limited to this. In steps 211 and 212, cleaning or overhaul of the processing unit 16 may be performed by an operator.

[0088] <Example 5> The cause of particle generation can be inferred from the distribution trend of particles on the doctor wafer DW. For example, if a particle distribution like that shown in Figure 10 is confirmed immediately after the fork of the substrate transfer device 13 removes the doctor wafer DW from the carrier C, it can be determined that the slot of the carrier C is contaminated. In Figure 10, particles are observed in the part of the doctor wafer DW that comes into contact with the slot of the carrier C.

[0089] 11 is confirmed immediately after the fork of the substrate transport device 17 removes the doctor wafer DW from the delivery part 14, it can be determined that the delivery part 14 is contaminated. In this case, it is considered that this is caused by particles that have fallen from the ceiling part of the delivery part 14 and are falling down.

[0090] 12 is confirmed immediately after (or at the beginning of) the processing of the doctor wafer DW by the processing unit 16, it can be determined that the three gripping jaws (arranged at equal intervals in the circumferential direction) of the spin chuck 30 are contaminated. If the gripping jaws are contaminated, the processing liquid attempting to splash outward from the doctor wafer DW collides with the gripping jaws, causing the particles adhering to the gripping jaws to fall off and contaminate the surface of the doctor wafer DW.

[0091] Also, although not shown, if particles are found near the part of the doctor wafer DW held by the forks 172 of the substrate transport device 17 (or 13) that comes into contact with the gripping jaws of the forks immediately after the doctor wafer DW is placed at the transport destination (e.g., the spin chuck of the processing unit 16), it can be determined that the holding jaws 173 of the forks 172 are contaminated.

[0092] <Example 6> 13A, 13B, and 13C show the relationship between the position of the nozzle 41 and the amount of particles when the processing liquid is supplied from the nozzle 41 to the rotating doctor wafer DW. The areas shaded in black are areas with a particularly large number of particles. In this case, there are many particles near the landing point of the processing liquid from the nozzle 41. In such a case, it is estimated that the processing liquid being discharged from the nozzle 41 contains a large number of particles.

[0093] When a liquid having a certain degree of light-shielding property is discharged from the nozzle 41 onto the doctor wafer DW, the landing point of the liquid on the doctor wafer DW can be confirmed based on pixel data acquired from the doctor wafer DW on the basis of data in the format shown in (A) to (C) of Figure 13. In other words, it can be confirmed whether the position control of the nozzle 41 is being performed appropriately.

[0094] 13D shows the state during shaking off and drying, where a ring-shaped area with many particles is formed on the periphery of the doctor wafer DW. In this case, it is considered that the drying conditions are inappropriate, or that the mist scattered from the doctor wafer DW is bounced off the collection cup and re-adheres to the doctor wafer DW.

[0095] <Detection of particle size using doctor wafer> Particle detection by the doctor wafer DW will be further described below. FIG. 14 is a schematic diagram showing a state in which a particle P larger than the pixel size exists above a plurality of pixels 105. As shown in FIG. 14, the thickness of the particle P is assumed to be thick at the center and thin at the periphery. In this case, most of the illumination light L irradiated to the center of the particle P is blocked by the particle P and does not reach the pixel 105. On the other hand, a part of the illumination light L irradiated to the periphery of the particle P passes through the particle. Also, the illumination light L may reach the pixel by going around the periphery of the particle P.

[0096] Fig. 15 is a schematic diagram showing the distribution of the amount of light received by each pixel 105 in the case shown in Fig. 14. One black dot corresponds to one pixel 105, and the larger the size of the black dot, the smaller the amount of light received.

[0097] Taking the above into consideration, the light intensity when the illumination light L reaches the pixel 105 as is (without being blocked by the particle P) may be set to 1, and if the intensity of the light reaching the pixel 105 is smaller than a predetermined threshold (for example, less than 0.8), it may be determined that a particle is present directly above the pixel 105. The threshold may be determined experimentally by comparing data obtained by a proven conventional method (for example, a method using laser reflection / diffraction) with data obtained using a doctor wafer DW.

[0098] When the intensity of light received by one pixel 105 is greater than a threshold value and the intensity of light received by the other pixel 105 is less than the threshold value, it can be determined that a part of the outline of a particle P exists between these adjacent pixels 105. By detecting all other adjacent pixels 105 having such a relationship, the outline of the particle P can be identified.

[0099] The threshold may be changed according to the particle size (which can be determined by the number of consecutive pixels where the light intensity is less than, for example, 0.8). For example, when a particle smaller than the pixel size (for example, about 5 nm) is present on one pixel, the threshold may be set to, for example, less than 0.5.

[0100] As mentioned above, it is also possible to detect other defects such as watermarks and scratches using the doctor wafer DW, because these defects also prevent the illumination light from entering the pixels. Watermarks can be detected using the same detection principle as particles, except that their light transmittance is higher than that of general particles.

[0101] When a scratch S occurs on the surface of the protective layer 106 of the doctor wafer DW, the illumination light L is redirected by the scratch S as shown in Fig. 16, and hardly reaches the pixel 105 directly below the scratch S. The scratch S extends continuously in a line across a large number of pixels 105. For this reason, when pixels 105 with small light receiving amounts are connected in a line, it can be determined that there is a scratch above these pixels 105.

[0102] <Regeneration of doctor wafers> It is not preferable to perform an inspection on a doctor wafer DW that has scratches S on its surface or has particles firmly attached thereto that cannot be removed by cleaning. In order to regenerate such a doctor wafer DW, the following regeneration method may be performed.

[0103] If the particles are firmly attached or if shallow scratches S are formed, the doctor wafer DW can be reused by thinly scraping off at least the vicinity of the outermost surface of the protective layer 106 by chemical treatment or CMP treatment. If a hydrophobic thin film is formed on the outermost surface of the protective layer 106, the hydrophobic thin film can be formed again after the above treatment.

[0104] If the scratch S is deep and the protective layer 106 of the doctor wafer DW consists of a pixel protection damper 106a and transparent glass (SiOx) 106b, the transparent glass 106b may be completely removed leaving the pixel protection damper 106a, and then a layer of transparent glass 106b may be formed again.

[0105] <Modification of Doctor Wafer> As described above, the basic function of the doctor wafer DW is to output the electric charge output from each pixel 105 of the light receiving layer 104 to the outside via the wiring layer 102 (including logic circuits, amplifiers, etc.). In this basic configuration, data acquisition and data transmission can only be performed when the electrodes of the doctor wafer DW and external electrodes (for example, electrodes of the gripping jaws of the spin chuck, electrodes of the holding jaws of the forks of the substrate transport mechanism 13, etc.) are in contact with each other.

[0106] To solve the above problems, the doctor wafer DW can be added to the basic configuration by combining one or more of the following components. This allows for flexible operation of the doctor wafer DW. (a) A memory unit 107a for temporarily storing pixel data (b) A power storage unit 107b that stores power for operating the doctor wafer DW (c) An antenna section 107c for contactless power supply to the doctor wafer DW (power reception of the doctor wafer DW) or for wireless transmission of data between the doctor wafer DW and an external device (for example, reception of a command to read pixel data and transmission of pixel data to an external device).

[0107] The memory unit 107a can be composed of, for example, DRAM, RRAM, MRAM, NAND type flash memory, etc. The power storage unit 107b can be composed of a battery, a capacitor, etc. The antenna unit can be composed of an amorphous soft magnetic material.

[0108] Fig. 17 shows a doctor wafer DW having a memory section 107a in addition to the wiring layer 102, the light receiving layer 104, and the protective layer 106. Fig. 18 shows a doctor wafer DW having a memory section 107a and a power storage section 107b in addition to the wiring layer 102, the light receiving layer 104, and the protective layer 106. Fig. 19 shows a doctor wafer DW having a memory section 107a, a power storage section 107b, and an antenna section 107c in addition to the wiring layer 102, the light receiving layer 104, and the protective layer 106.

[0109] 20, a nanolens array may be incorporated into the protective layer 106. In this case, an individual nanolens 109 may be disposed directly above each pixel 105. In this case, too, the top surface of the protective layer 106 may be formed of transparent glass (SiOx) or the like.

[0110] Instead of providing the light receiving layer 104 on the entire surface of the doctor wafer DW, the light receiving layer 104 may be provided only on a part of the surface of the doctor wafer DW. For example, as shown in FIG. 21, the light receiving layer 104 may be provided only on a plurality of lines extending in the diameter direction of the doctor wafer DW. In this way, the amount of data to be handled is reduced, so that the burden of data transmission / reception and calculation processing is reduced. For example, when performing an inspection that only concerns the total amount of particles on the surface of the doctor wafer DW (not the distribution), the inspection efficiency is improved.

[0111] Each layer of the doctor wafer DW, such as the wiring layer 102 and the light receiving layer 104, can be formed on a semiconductor wafer using a semiconductor device manufacturing technique (film formation technique). However, the doctor wafer DW may be constructed by attaching a pre-formed imaging device onto a substrate.

[0112] In the above embodiment, the electrodes 35 are provided on the gripping jaws 34 of the mechanical chuck, but this is not limited to the above. When the spin chuck is a vacuum chuck, an electrode may be provided on the vacuum chuck and an electrode may be provided on the central portion of the rear surface of the doctor wafer DW that contacts the vacuum chuck.

[0113] According to the above embodiment, by using the doctor wafer DW, particle level inspection can be performed at various locations in the substrate processing system 1. By installing an illumination device that appropriately irradiates the doctor wafer DW with illumination light, particle level inspection can be performed even during processing or transportation of the doctor wafer DW. In addition, by providing the memory unit 107a, the power storage unit 107b, the antenna unit 107c, etc. on the doctor wafer DW, it is possible to perform particle level inspection at any timing. This makes it possible to easily and quickly identify the cause of particle generation.

[0114] In the conventional particle level inspection method using a stand-alone particle inspection device, it is only possible to compare particle levels before and after processing and before and after transport, and it is not possible to inspect particle levels during processing and transport. Of course, it is not possible to inspect a wafer in a wet state. Furthermore, in order to identify the cause of particle generation, it is necessary to process many wafers and compare the processing results. Furthermore, it takes a long time to inspect one wafer. Therefore, it takes a very long time to identify the cause of particle generation, and the cost is high. Furthermore, there is a possibility that the wafer will be contaminated while being transported to the stand-alone particle inspection device. The above embodiment can solve many of these problems.

[0115] The embodiments disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0116] DW Test Board 100 Base material 102+104 image sensor 106 Protective layer 108 Output section (electrode)

Claims

1. a processing unit for processing a substrate; a transfer section through which the substrate to be processed in the processing unit is transferred; a transport mechanism configured to transport the substrate between the loading / unloading section and the processing unit; an inspection board comprising a plate-shaped base material, an imaging element provided on at least a portion of a surface of the base material, a light-transmitting protective layer made of PFA or PTFA formed on the surface of the imaging element, and an output section that outputs an output of the imaging element to the outside of the inspection board; and an illumination device that irradiates the inspection board with illumination light for inspection in order to detect contaminants adhering to the inspection board when the inspection board is processed by the processing unit or transported by the transport mechanism; Equipped with A substrate processing apparatus, wherein the processing unit has a substrate holding part, a nozzle that supplies a processing fluid to the substrate held by the substrate holding part, and a nozzle arm that supports and moves the nozzle, and the lighting device is provided on the nozzle arm.

2. A processing unit for processing a substrate; a transfer section through which the substrate to be processed in the processing unit is transferred; a transport mechanism configured to transport the substrate between the loading / unloading section and the processing unit; an inspection board comprising a plate-shaped base material, an imaging element provided on at least a portion of a surface of the base material, a light-transmitting protective layer made of PFA or PTFA formed on the surface of the imaging element, and an output section that outputs an output of the imaging element to the outside of the inspection board; and an illumination device that irradiates the inspection board with illumination light for inspection in order to detect contaminants adhering to the inspection board when the inspection board is processed by the processing unit or transported by the transport mechanism; Equipped with The lighting device is provided on a ceiling of an entrance / exit of the processing unit above a path through which the transport mechanism passes when loading / unloading the substrate into / from the processing unit.

3. The substrate processing apparatus according to claim 1 , further comprising a device including a signal processing device for processing data output from an output section of said test substrate, or a power supply for supplying power for operating said test substrate.

Images