Mounting method, mounting device, and mounting program

Abstract

This mounting method includes: a first imaging step for obtaining a first image by imaging a die main surface including an alignment mark provided on a semiconductor die, which is an object to be mounted, via an NCF which is a covering member that covers the alignment mark; a first extraction step for extracting the alignment mark from the first image; a standby step for waiting until a predetermined time elapses in case of a failure to extract the alignment mark as the result of the first extraction step; a second imaging step for obtaining a second image by imaging the die main surface again after the standby step; and a second extraction step for extracting the alignment mark from the second image.

Description

Mounting method, mounting device, and mounting program

[0001] The present invention relates to a mounting method, a mounting device, and a mounting program.

[0002] Bonding, one of the processes for manufacturing semiconductor devices, involves mounting a semiconductor die, which has been diced to a predetermined size, onto a substrate, which is a target object. Bonding includes the operations of detachably holding the semiconductor die, transporting the held semiconductor die to a predetermined position, and fixing the transported semiconductor die to the substrate.

[0003] Patent Document 1 discloses a technique for fixing a semiconductor die to a substrate, in which the position of a semiconductor die held by a mounting tool is accurately adjusted relative to the substrate to which the semiconductor die is to be bonded.

[0004] A semiconductor die may be bonded to a substrate with the bonding surface of the semiconductor die, on which electrodes are provided, facing the bonding surface of the substrate, on which electrodes are provided. This type of bonding is also called flip-chip bonding. In flip-chip bonding, the electrodes of the semiconductor die are bonded to the electrodes of the substrate by soldering. Patent Documents 2 and 3 disclose techniques for applying a flux for solder bonding to the bonding surface of the mounting object.

[0005] JP 2017-157682 A International Publication No. 2023-002557 International Publication No. 2023-017620

[0006] When fixing an object to be mounted to a target object, it is important to accurately grasp the position of the object relative to the target object. The object to be mounted has alignment marks to define the position of the object to be mounted. The area including the alignment marks is imaged by a camera. The position of the object to be mounted is grasped using the image obtained by imaging.

[0007] However, even if an alignment mark is captured in an image obtained by imaging, it may not be possible to extract the alignment mark from the image. If the alignment mark extraction fails, it becomes impossible to accurately determine the position of the mounting object relative to the target object. Therefore, a mounting object from which the alignment mark cannot be extracted may be treated as a defective product. In other words, a mounting object that is a good product may be treated as a defective product.

[0008] The present invention provides a mounting method, a mounting device, and a mounting program that reduce the number of mounting objects that are treated as defective products.

[0009] An implementation method that is one form of the present invention includes a first imaging step of obtaining a first image by imaging a main surface of an object including an alignment mark provided on the object through a covering member that covers the alignment mark; a first extraction step of extracting the alignment mark from the first image; a waiting step of waiting until a predetermined time has elapsed if extraction of the alignment mark fails as a result of the first extraction step; a second imaging step of obtaining a second image by imaging the main surface of the object again after the waiting step; and a second extraction step of extracting the alignment mark from the second image.

[0010] According to this mounting method, if the alignment mark fails to be extracted from the first image acquired in the first imaging step, the method waits for a predetermined time to elapse, and then acquires an image again and extracts the alignment mark from the image. Some factors that hinder alignment mark extraction may be resolved over time. Therefore, even if the alignment mark fails to be extracted as a result of the first extraction step, the alignment mark may still be successfully extracted as a result of the second extraction step. This makes it possible to differentiate between objects that are deemed defective based on the results of the first extraction step and objects that are deemed good based on the results of the second extraction step. As a result, the number of objects that are deemed defective despite being good can be reduced.

[0011] In the above mounting method, the target object may be a semiconductor die. The waiting step may include applying heat to the semiconductor die. This step can further increase the likelihood of eliminating factors that inhibit extraction of the alignment marks.

[0012] In the above mounting method, the object may be provided to a next manufacturing process if the alignment mark has been successfully extracted as a result of the first extraction step. According to this step, the object from which the alignment mark has been successfully extracted can be provided to the next manufacturing process.

[0013] In the above mounting method, if the second extraction step results in successful extraction of the alignment mark, the object may be provided to the next manufacturing process, and if the second extraction step results in unsuccessful extraction of the alignment mark, the object may not be provided to the next manufacturing process. This step makes it possible to obtain an object that can be provided to the next manufacturing process from the object for which the first extraction step failed to extract the alignment mark.

[0014] In the mounting method, the object may be a substrate. In the waiting step, a time may be set during which the influence of the flux applied to the substrate on the second image is reduced. This step can reduce the number of substrates determined to be defective.

[0015] According to another aspect of the present invention, a mounting apparatus includes a bonding head that detachably holds a semiconductor die having a die alignment mark thereon, a camera that images the die main surface on which the die alignment mark is formed or the substrate main surface of the substrate on which the substrate alignment mark is formed through a covering member that covers the die alignment mark or the substrate alignment mark, and a controller that controls the camera and the bonding head. The controller executes a first imaging operation of imaging the die main surface or the substrate main surface to obtain a first image, a first extraction operation of extracting the die alignment mark or the substrate alignment mark from the first image, a standby operation of waiting until a predetermined time has elapsed if the first extraction operation fails to extract the diamond alignment mark or the substrate alignment mark, a second imaging operation of imaging the die main surface or the substrate main surface again to obtain a second image, and a second extraction operation of extracting the diamond alignment mark or the substrate alignment mark from the second image.

[0016]

[0013] In another aspect of the present invention, there is provided a mounting program for a mounting apparatus including a bonding head that detachably holds a semiconductor die provided with a die alignment mark, and a camera that images the die main surface on which the die alignment mark is formed or the substrate main surface of the substrate on which the substrate alignment mark is formed, through a covering member that covers the die alignment mark or the substrate alignment mark. The mounting program causes a computer to function as a first imaging function unit that obtains a first image by imaging the die main surface or the substrate main surface, a first extraction function unit that extracts the diamond alignment mark or the substrate alignment mark from the first image, a waiting function unit that waits until a predetermined time has elapsed if the operation of the first extraction function unit fails to extract the diamond alignment mark or the substrate alignment mark, a second imaging function unit that obtains a second image by re-imaging the die main surface or the substrate main surface after the operation of the waiting function unit, and a second extraction function unit that extracts the diamond alignment mark or the substrate alignment mark from the second image.

[0017] As with the mounting method, the mounting device and the mounting program can also reduce the number of objects that are treated as defective despite being non-defective.

[0018] According to the mounting method, mounting device, and mounting program of the present invention, the number of objects that are treated as defective can be reduced.

[0019] FIG. 1 is a simplified diagram showing the configuration of a mounting apparatus to which a mounting method and a mounting program according to this embodiment are applied. FIG. 2 is an enlarged cross-sectional view of a semiconductor die. FIG. 3(a) is an example of a reference alignment mark. FIG. 3(b) is an example of an image in which an alignment mark has been successfully extracted. FIG. 3(c) is an example of an image in which an alignment mark has not been extracted. FIG. 4 is a flowchart showing the main steps of the mounting method according to this embodiment. FIG. 5(a) is a cross-sectional view of a semiconductor die in which no foreign matter that would prevent the alignment mark from being extracted is present. FIG. 5(b) is a cross-sectional view of a semiconductor die in which a foreign matter that would prevent the alignment mark from being extracted is present. FIG. 6 is a diagram showing the physical configuration of a controller. FIG. 7 is a functional block diagram of the controller. FIG. 8(a) is a cross-sectional view illustrating a case in which an alignment mark fails to be extracted due to flux. FIG. 8(b) is a cross-sectional view illustrating a case in which an alignment mark is successfully extracted. FIG. 9 is a flowchart showing the main steps of a modified mounting method.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0021] As shown in Fig. 1, a mounting apparatus 1 attaches a semiconductor die 2 (object) to a substrate 3. The mounting apparatus 1 includes a pickup unit 11, a bonding unit 12, and a controller 13. The pickup unit 11 picks up the semiconductor die 2 from a pickup stage 11S. The pickup unit 11 then passes the semiconductor die 2 to the bonding unit 12. The bonding unit 12 mounts the received semiconductor die 2 on a substrate 3 on a bonding stage 12S. The controller 13 controls the operation of the pickup unit 11 and the bonding unit 12 described above.

[0022] The pickup unit 11 includes a guide rail 11G, a pickup stage 11S, a pickup head 11H, and a camera 11C. The guide rail 11G is a base for moving the pickup head 11H back and forth in a predetermined direction. The guide rail 11G extends, for example, from the pickup area to the bonding unit 12.

[0023] The pickup stage 11S has a plurality of semiconductor dies 2 placed thereon as targets. The pickup stage 11S may additionally have desired functions required for the pickup head 11H to pick up the semiconductor dies 2. For example, the pickup stage 11S may have a function of pushing up the semiconductor dies 2 that are targets of the pickup operation.

[0024] The pickup head 11H is connected to the guide rail 11G. The pickup head 11H moves back and forth along the guide rail 11G. The pickup head 11H has a function of detachably holding the semiconductor die 2. The function of detachably holding the semiconductor die 2 may be realized by a known structure.

[0025] The camera 11C captures an image of a predetermined area of ​​the semiconductor die 2 selected as the pick-up target. The image obtained by capturing the image is output to the controller 13, for example.

[0026] The bonding unit 12 includes a guide rail 12G, a bonding stage 12S, a bonding head 12H, and a camera 12C.

[0027] The guide rail 12G is a base for reciprocating the bonding head 12H in a predetermined direction. The guide rail 12G extends, for example, from the pickup unit 11 to the bonding stage 12S where the bonding operation is performed.

[0028] The bonding stage 12S is configured to hold the substrate 3 on which the semiconductor die 2 is mounted. The bonding stage 12S may additionally have desired functions required for mounting. For example, the bonding stage 12S may have a function to hold the position of the substrate 3.

[0029] The bonding head 12H is connected to a guide rail 12G. The bonding head 12H moves back and forth along the guide rail 12G. The bonding head 12H also has a function of detachably holding the semiconductor die 2. The function of detachably holding the semiconductor die 2 may be achieved by a known structure. For example, the bonding head 12H has a vacuum suction mechanism as an attachment / detachment mechanism. Furthermore, the bonding head 12H has a function of pressing the semiconductor die 2 against the substrate 3 with a predetermined force. The bonding head 12H may also have a built-in heater 121 and have a function of providing heat to the semiconductor die 2.

[0030] The camera 12C captures an image of a predetermined area of ​​the semiconductor die 2 held by the bonding head 12H. The image obtained by this capture may be used to obtain relative position information between the semiconductor die 2 and the substrate 3.

[0031] The controller 13 controls the operations of the bonding unit 12 and the pick-up unit 11. Details of the controller 13 will be explained in detail in a later paragraph.

[0032] Here, attention is focused on the semiconductor die 2. The die main surface 2a (main surface of the object) and the die back surface 2b of the semiconductor die 2 are reversed between the time when the semiconductor die 2 is picked up from the pickup stage 11S and the time when the semiconductor die 2 is mounted on the substrate 3. It is assumed that the die main surface 2a has the function of being electrically connected to the substrate 3. In other words, when the semiconductor die 2 is attached to the substrate 3, the die main surface 2a faces the substrate main surface 3a. Therefore, the die back surface 2b can be defined as the surface that does not face the substrate main surface 3a when the semiconductor die 2 is attached to the substrate 3.

[0033] The semiconductor dies 2 lined up on the pickup stage 11S have their die main surfaces 2a facing upward and their die back surfaces 2b facing the stage main surface. Therefore, the pickup unit 11 holds the die main surfaces 2a. Next, the pickup unit 11 rotates 180 degrees. As a result, the die back surfaces 2b face upward. Next, the bonding unit 12 holds the die back surfaces 2b. Then, the pickup unit 11 releases the die main surfaces 2a. As a result, the semiconductor die 2 is in a state where the die main surfaces 2a face downward. Then, the bonding unit 12 mounts the die main surfaces 2a of the semiconductor die 2 at a predetermined position on the substrate 3. This series of mounting operations is called a flip-chip process or flip-chip bonding.

[0034] As described above, the flip chip process includes operations such as picking up the semiconductor die 2, mounting the semiconductor die 2, and transferring the semiconductor die 2. These operations require position information of the semiconductor die 2. For example, in the mounting operation of the semiconductor die 2, relative position information of the semiconductor die 2 with respect to the substrate 3 is used to accurately mount the semiconductor die 2 at a predetermined position on the substrate 3.

[0035] Position information of the semiconductor die 2 is obtained using an alignment mark 2M (diamond alignment mark) provided on the semiconductor die 2. Specifically, an image of an area including the alignment mark 2M is captured by the camera 12C. The controller 13 processes the captured image to obtain position information of the semiconductor die 2.

[0036] 2 is an enlarged cross-sectional view showing the mounting operation of the semiconductor die 2. A plurality of bump electrodes 21 are provided on the die main surface 2a of the semiconductor die 2. Alignment marks 2M are also provided on the die main surface 2a. A non-conductive film called an NCF (Non Conductive Film) (hereinafter referred to as "NCF 22") is also provided on the die main surface 2a. The NCF 22 (covering member) is attached to the entire die main surface 2a. Therefore, the bump electrodes 21 and alignment marks 2M are covered by the NCF 22.

[0037] Then, when an image is taken using the camera 12C, the alignment mark 2M is visible through the NCF 22. Ideally, no foreign matter exists between the film main surface 22a of the NCF 22 and the die main surface 2a of the semiconductor die 2. When no foreign matter exists, the edge of the alignment mark 2M that appears in the image is the exact outer shape of the alignment mark 2M.

[0038] However, foreign matter may exist between the film main surface 22 a of the NCF 22 and the die main surface 2 a of the semiconductor die 2. Examples of foreign matter include air bubbles and fine dust. For example, if an air bubble 2B exists on the edge of the alignment mark 2M, the edge of the alignment mark 2M that appears in the image will differ from the outer shape of the alignment mark 2M itself.

[0039] For example, the shape shown in FIG. 3A is defined as the reference alignment mark 2D. Then, in the process of obtaining position information, a region having the same shape as the reference alignment mark 2D is searched for in the image. A region having the same shape as the reference alignment mark 2D can be extracted from image D1 shown in FIG. 3B. However, it is possible that a region having the same shape as the reference alignment mark 2D cannot be extracted from image D1 shown in FIG. 3C. If a region having the same shape as the reference alignment mark 2D cannot be extracted, position information of the semiconductor die 2 cannot be obtained, and the semiconductor die 2 cannot be accurately mounted in a predetermined region on the substrate 3. As a result, if a region having the same shape as the reference alignment mark 2D cannot be extracted, the semiconductor die 2 is treated as a defective product.

[0040] The mounting method, mounting apparatus, and mounting program of this embodiment prevent a non-defective semiconductor die 2 from being treated as a defective product because the alignment mark 2M cannot be extracted from the image. The mounting method, mounting apparatus, and mounting program of this embodiment can be applied to any process in which an image of the alignment mark 2M is captured via the NCF 22 in the process of manufacturing a semiconductor device.

[0041] <Mounting Method> The mounting method of this embodiment will be described with reference to Fig. 4. The mounting method is executed by the controller 13. Specifically, the mounting method includes controlling the camera 12C by the controller 13, processing image data provided from the camera 12C, and controlling the pickup unit 11 or the bonding unit 12 based on the processing results.

[0042] First, the controller 13 controls the camera 12C to capture an image of the die main surface 2a (S11). As a result of executing step S11, the controller 13 receives a first image D1 from the camera 12C.

[0043] Next, the controller 13 extracts the alignment mark 2M from the first image D1 (S12). The result of executing step S12 is either "successful in extracting the alignment mark 2M" or "failed in extracting the alignment mark 2M." Any method may be used for image processing to extract the alignment mark 2M. For example, as shown in FIG. 5A, if there are no bubbles or dust particles between the semiconductor die 2 and the NCF 22 that would straddle the edge of the alignment mark 2M, the controller 13 may be successful in extracting the alignment mark 2M from the first image D1. On the other hand, as shown in FIG. 5B, if there are bubbles or dust particles between the semiconductor die 2 and the NCF 22 that would straddle the edge of the alignment mark 2M, the controller 13 may fail to extract the alignment mark 2M from the first image D1.

[0044] Next, the controller 13 determines whether extraction of the alignment mark 2M was successful (S13). If the result of executing step S13 is that "extraction of the alignment mark 2M was successful" (S13: YES), the controller 13 passes the semiconductor die 2 to the next step (S14). For example, if this mounting method is executed in the step of mounting the semiconductor die 2 on the substrate 3 by the bonding unit 12, the next step of bonding the semiconductor die 2 to the substrate 3 may be executed. On the other hand, if the result of executing step S13 is that "extraction of the alignment mark 2M failed" (S13: NO), the controller 13 executes the next step S15.

[0045] Next, the controller 13 waits until a predetermined time has elapsed (S15). As described in the explanation of step S12, if there is an air bubble or dust that straddles the edge of the alignment mark 2M, extraction of the alignment mark 2M from the first image D1 may fail. Some foreign matter that hinders extraction of the alignment mark 2M may disappear over time. Specifically, if there is an air bubble 2B between the semiconductor die 2 and the NCF 22 that straddles the edge of the alignment mark 2M, the air bubble 2B may disappear over time.

[0046] Therefore, if the controller 13 fails to extract the alignment mark 2M, it waits for a predetermined time (S15). During this waiting period, the controller 13 does not output a command to move the bonding unit 12 or a command to move the field of view of the camera 12C. In other words, the controller 13 maintains the state of the field of view of the camera 12C in the imaging operation of step S11. If the foreign matter is a bubble 2B, it may disappear after this waiting period has elapsed. If the foreign matter is dust, it will not disappear even after this waiting period has elapsed. As a result, among the alignment marks 2M for which extraction failed in step S12, there may be some for which extraction of the alignment mark 2M is successful when imaging and extraction are performed again.

[0047] In step S15, additional operations may be performed while waiting for the passage of a predetermined time. For example, an operation of applying heat to the semiconductor die 2 may be performed as needed (S151). More specifically, heat is applied to the NCF 22 via the semiconductor die 2 using a heater 121 built into the bonding head 12H. This heat may also promote the disappearance of the bubbles 2B.

[0048] Next, the controller 13 again captures an image of the die main surface 2a after a predetermined time has elapsed. In step S16, the state of the field of view of the camera 12C is maintained during the predetermined time period. Therefore, when the die main surface 2a is again captured in step S16, a second image D2 having the same field of view as the image captured in step S11 is obtained. Note that the "same field of view" described here does not require that the areas of the die main surface 2a and areas that are not the die main surface 2a included in the image strictly match between the first image and the second image. In other words, the "same field of view" described here means that the alignment mark 2M included in the first image and the alignment mark 2M included in the second image are the same.

[0049] Next, the controller 13 extracts the alignment mark 2M from the second image D2 (S17). This step S17 is the same as step S12, except that the data used for extraction is different. Therefore, the result of executing this step S17 is either "Extraction of the alignment mark 2M was successful" or "Extraction of the alignment mark 2M failed."

[0050] The controller 13 then determines whether extraction of the alignment mark 2M was successful (S18). If the result of executing step S18 is that "extraction of the alignment mark 2M was successful" (S18: YES), the controller 13 passes the semiconductor die 2 to the next process (S14). In this case, the first imaging and extraction process failed to extract the alignment mark 2M, and the die determined to be defective is provided to the next manufacturing process as a non-defective product. On the other hand, if the result of executing step S18 is that "extraction of the alignment mark 2M failed" (S18: NO), the controller 13 does not pass the semiconductor die 2 to the next process (S19). For example, the controller 13 may discard the semiconductor die 2 held by the bonding head 12H as a defective product in a designated box or the like without bonding it to the substrate 3.

[0051] <Controller and Program> Next, a description will be given of the controller 13 and the mounting program P that execute the mounting method. The controller 13 executes the mounting program P to execute the mounting method shown in the flow of FIG.

[0052] The hardware configuration of the controller 13 will be described with reference to Fig. 6. The controller 13 is configured by a computer 50. The computer 50 has a processor 51, which is a CPU (Central Processing Unit), a main memory unit 52, an auxiliary memory unit 53, an external communication unit 54, an input unit 55, and an output unit 56. The controller 13 is configured by one or more computers 50, which are configured by this hardware and software such as programs.

[0053] When the controller 13 is configured by a plurality of computers 50, these computers 50 may be connected locally or via a communication network such as the Internet or an intranet. This connection logically constitutes one controller 13.

[0054] The processor 51 executes an operating system, application programs, etc. The main memory 52 is composed of a ROM (Read Only Memory) and a RAM (Random Access Memory). The auxiliary memory 53 is a storage medium composed of a hard disk, flash memory, etc. The auxiliary memory 53 generally stores a larger amount of data than the main memory 52. ​​The input unit 55 is composed of a keyboard, a mouse, a touch panel, a microphone for voice input, etc.

[0055] The auxiliary storage unit 53 stores in advance an implementation program P and data necessary for processing. The implementation program P causes the computer 50 to execute each functional element of the controller 13. For example, the implementation program P is read by the processor 51 or the main storage unit 52, and causes at least one of the processor 51, the main storage unit 52, the auxiliary storage unit 53, the external communication unit 54, the input unit 55, and the output unit 56 to operate. For example, the implementation program P reads and writes data from and to the main storage unit 52 and the auxiliary storage unit 53.

[0056] The implementation program P may be provided in the form of being recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, a semiconductor memory, etc. The implementation program P may also be provided as a data signal via a communication network.

[0057] 7, the controller 13 operates as a plurality of functional components by the processor 51 sequentially processing the implementation program P and data deployed in the memory 52M, which is the main storage unit 52. The controller 13 has, as functional components, a head control unit 131, a camera control unit 132, an alignment mark extraction unit 133, an extraction result determination unit 134, and a wait time setting unit 135.

[0058] The head control unit 131 outputs a head command C131 that controls the operation of the pickup unit 11 and the bonding unit 12. The head command C131 may include a command related to the movement of the pickup head 11H or the bonding head 12H in a predetermined direction, a command related to the operation of picking up the semiconductor die 2 by the pickup head 11H, a command related to the operation of transferring the semiconductor die 2 from the pickup head 11H to the bonding head 12H, and a command related to the operation of bonding the semiconductor die 2 to the substrate 3 by the bonding head 12H.

[0059] The head control unit 131 may also generate and output a head command C131 using the output of the extraction result determination unit 134. For example, if the extraction result determination unit 134 determines that "extraction of the alignment mark 2M was successful," the head control unit 131 may output a head command C131 that causes the next operation to be executed. In other words, the head control unit 131 executes step S14 in the mounting method.

[0060] The camera control unit 132 outputs a camera command C132 that controls the operation of the camera 12 C. The camera command C132 may include a command related to the operation of moving, enlarging, or reducing the field of view of the camera 12 C, and a command related to the image capturing operation by the camera 12 C. In other words, the camera control unit 132 executes steps S11 and S16 in the implementation method.

[0061] The camera control unit 132 may also generate and output a camera command C132 using the output of the extraction result determination unit 134. For example, if the extraction result determination unit 134 determines that "extraction of the alignment mark 2M has failed," the camera control unit 132 may output a camera command C132 to cause the camera 12C to perform an image capturing operation again after a predetermined time has elapsed.

[0062] The alignment mark extraction unit 133 reads the first image D1 or the second image D2 from the memory 52M and executes a process of extracting the alignment mark 2M from the read first image D1 or the second image D2. That is, the alignment mark extraction unit 133 executes steps S12 and S17 in the mounting method. Then, the alignment mark extraction unit 133 may add additional information indicating "extraction of the alignment mark 2M succeeded" or "extraction of the alignment mark 2M failed" to the first image D1 or the second image D2 and output the result to the memory 52M. Furthermore, if the alignment mark extraction unit 133 determines that "extraction of the alignment mark 2M succeeded," it may further execute a process of obtaining position information of the semiconductor die 2 and output the position information to the memory 52M.

[0063] The extraction result determination unit 134 reads the first image D1 or the second image D2 with the additional information from the memory 52M and determines whether the content of the additional information indicates "successful extraction of the alignment mark 2M" or "failed extraction of the alignment mark 2M." That is, the extraction result determination unit 134 executes steps S13 and S18 in the mounting method. If the content of the additional information indicates "successful extraction of the alignment mark 2M," the extraction result determination unit 134 outputs information permitting execution of the next manufacturing process. This information is read into the head control unit 131 via the memory 52M. If the content of the additional information indicates "failed extraction of the alignment mark 2M," the extraction result determination unit 134 outputs information prohibiting execution of the next manufacturing process. This information is read into the wait time setting unit 135 via the memory 52M.

[0064] Based on the information stored in memory 52M that prohibits the execution of the next manufacturing process, waiting time setting unit 135 maintains the states of camera 12C, pickup unit 11, and bonding unit 12. In other words, waiting time setting unit 135 executes step S15 in the mounting method.

[0065] <Effects> The mounting method includes a first imaging step (S11) of obtaining a first image D1 by imaging the die main surface 2a including the alignment mark 2M provided on the semiconductor die 2, which is the target object, through the NCF 22, which is a covering member that covers the alignment mark 2M; a first extraction step (S12) of extracting the alignment mark 2M from the first image D1; a waiting step (S15) of waiting until a predetermined time has elapsed if extraction of the alignment mark 2M has failed as a result of the first extraction step (S12); a second imaging step (S16) of obtaining a second image D2 by imaging the die main surface 2a again after the waiting step (S15); and a second extraction step (S17) of extracting the alignment mark 2M from the second image D2.

[0066] The mounting apparatus 1 includes a bonding head 12H that detachably holds a semiconductor die 2 on which an alignment mark 2M is provided, a camera 12C that images the die main surface 2a on which the alignment mark 2M is formed through an NCF 22 that is a covering member that covers the alignment mark 2M, and a controller 13 that controls the camera 12C and the bonding head 12H. The controller 13 executes a first imaging operation that obtains a first image D1 by imaging the die main surface 2a, a first extraction operation that extracts the alignment mark 2M from the first image D1, a standby operation that waits until a predetermined time has elapsed if extraction of the alignment mark 2M fails as a result of the first extraction operation, a second imaging operation that obtains a second image D2 by imaging the die main surface 2a again after the standby operation, and a second extraction operation that extracts the alignment mark 2M from the second image D2.

[0067] The mounting program P is for a mounting apparatus 1 that includes a bonding head 12H that detachably holds a semiconductor die 2 on which alignment marks 2M are provided, and a camera 12C that images the die main surface 2a on which the alignment marks 2M are formed through a covering member that covers the alignment marks 2M. The mounting program P causes a computer to function as a first imaging function unit that obtains a first image D1 by imaging the die main surface 2a, a first extraction function unit that extracts the alignment marks 2M from the first image D1, a standby function unit that waits until a predetermined time has elapsed if the operation of the first extraction function unit fails to extract the alignment marks 2M, a second imaging function unit that obtains a second image D2 by re-imaging the die main surface 2a after the operation of the standby function unit, and a second extraction function unit that extracts the alignment marks 2M from the second image D2.

[0068] According to the mounting method, mounting apparatus 1, and mounting program P, if extraction of the alignment mark 2M from the first image D1 obtained in the first imaging step (S11) fails, the system waits for a predetermined time to elapse, and then re-acquires an image and extracts the alignment mark 2M from the image. Air bubbles 2B, which are an example of a factor that inhibits extraction of the alignment mark 2M, may disappear over time. Therefore, even if extraction of the alignment mark 2M fails as a result of the first extraction step (S12), extraction of the alignment mark 2M may be successful as a result of the second extraction step (S17). This allows for the selection of a semiconductor die 2 that is determined to be a non-defective product based on the results of the second extraction step (S17) from a semiconductor die 2 that is determined to be a defective product based on the results of the first extraction step (S12). As a result, the number of non-defective semiconductor dies 2 that are treated as defective can be reduced.

[0069] In the waiting step (S15), heat is applied to the semiconductor die 2. The step (S151) of applying heat to the semiconductor die 2 can further increase the possibility that the air bubbles 2B, which are a factor that inhibits extraction of the alignment marks 2M, will disappear.

[0070] If the extraction of the alignment mark 2M is successful as a result of the first extraction step (S12), the semiconductor die 2, which is the target, is provided to the next manufacturing process. According to this step (S12), the semiconductor die 2 from which the extraction of the alignment mark 2M has been successful can be provided to the next manufacturing process.

[0071] As a result of the second extraction step (S17), if the extraction of the alignment mark 2M is successful, the semiconductor die 2, which is the target, is provided to the next manufacturing process. If the extraction of the alignment mark 2M is unsuccessful, the semiconductor die 2 is not provided to the next manufacturing process. This step (S17) makes it possible to obtain a die that can be provided to the next manufacturing process from those for which the extraction of the alignment mark 2M failed in the first extraction step (S12).

[0072] <Modifications> Examples of the mounting method, mounting device, and mounting program have been described above. The mounting method, mounting device, and mounting program are not limited to the above examples and may be implemented in various forms.

[0073] In the embodiment, a case where the alignment mark 2M cannot be extracted from an image captured through the NCF 22 is illustrated. The mounting method, mounting device, and mounting program can also be applied to other situations in the process of manufacturing a semiconductor device. Flux 3F may be applied to the board electrodes 31 provided on the main surface 3a of the substrate 3 and the surrounding areas of the board electrodes 31 to bond the board electrodes 31 to the bump electrodes 21 of the semiconductor die 2. The flux 3F has a relatively high viscosity. Therefore, as shown in FIG. 8( a), although the flux 3F covers the entire surface of the alignment mark 2N (substrate alignment mark) immediately after application, the surface of the flux 3F becomes curved due to the surface tension of the flux 3F. In this case, the thickness of the flux 3F on the alignment mark 2N may vary partially. The substrate 3 is an example of an object.

[0074] If the alignment mark 2N is imaged by the camera 12C in this state, extraction of the alignment mark 2N may fail. This is because differences in the thickness of the flux 3F on the alignment mark 2N may cause differences in the refractive index, which may ultimately cause distortion in the image of the alignment mark 2N formed on the camera 12C.

[0075] Therefore, as shown in the flowchart of FIG. 9 , if extraction of the alignment mark 2N from the image obtained in step S11A fails in step S12 ( S13: NO), the process waits until a predetermined time has elapsed ( S15 ). As this time passes, the flux 3F gradually flows over the substrate main surface 3a and eventually converges to a state in which it covers the entire alignment mark 2N with a generally uniform thickness (see FIG. 8B ). The image obtained by capturing the substrate main surface 3a in step S16A is likely to contain an undistorted alignment mark 2N. Performing the process of extracting the alignment mark 2N using such an image ( S17 ) may result in successful extraction of the alignment mark 2N. The predetermined time set in step S15 may be set by experimentally determining the effect of the flux 3F on the captured image of the substrate main surface 3a, or it may be set during production operations.

[0076] Even with this modification, among those for which extraction of the alignment mark 2N failed in the first imaging and extraction, there may be some for which extraction of the alignment mark 2N succeeds in the second imaging and extraction, which results in a reduction in the number of substrates 3 that are determined to be defective.

[0077] 1...mounting device, 2...semiconductor die (object), 2a...die main surface (object main surface), 2M...alignment mark (die alignment mark), 2N...alignment mark (substrate alignment mark), 3...substrate, 3a...substrate main surface, 11C, 12C...camera, 12H...bonding head, 13...controller, 22...NCF (covering member), 50...computer, D1...first image, D2...second image, P...mounting program.

Claims

1. A first imaging step of obtaining a first image by imaging a main surface of an object including an alignment mark provided on the object through a covering member covering the alignment mark; a first extraction step of extracting the alignment mark from the first image; a waiting step of waiting until a predetermined time elapses when the extraction of the alignment mark fails as a result of the first extraction step; a second imaging step of obtaining a second image by imaging the main surface of the object again after the waiting step; and a second extraction step of extracting the alignment mark from the second image. A mounting method.

2. The object is a semiconductor die, and in the waiting step, heat is applied to the semiconductor die. The mounting method according to claim 1.

3. The mounting method according to claim 1, wherein when the extraction of the alignment mark is successful as a result of the first extraction step, the object is provided to the next manufacturing process.

4. The mounting method according to claim 1, wherein when the extraction of the alignment mark is successful as a result of the second extraction step, the object is provided to the next manufacturing process, and when the extraction of the alignment mark fails, the object is not provided to the next manufacturing process.

5. The object is a substrate, and in the waiting step, a time is set during which the influence of the flux applied to the substrate on the second image is reduced. The mounting method according to claim 1.

6. A mounting apparatus comprising: a bonding head that removably holds a semiconductor die provided with a die alignment mark; a camera that images a main surface of the die on which the die alignment mark is formed or a main surface of a substrate on which a substrate alignment mark is formed, via a covering member that covers the die alignment mark or the substrate alignment mark; and a controller that controls the camera and the bonding head, wherein the controller executes: a first imaging operation of obtaining a first image by imaging the main surface of the die or the main surface of the substrate; a first extraction operation of extracting the die alignment mark or the substrate alignment mark from the first image; a standby operation of waiting until a predetermined time elapses when the extraction of the die alignment mark or the substrate alignment mark fails as a result of the first extraction operation; a second imaging operation of obtaining a second image by imaging the main surface of the die or the main surface of the substrate again after the standby operation; and a second extraction operation of extracting the die alignment mark or the substrate alignment mark from the second image.

7. A mounting program for a mounting apparatus comprising: a bonding head that removably holds a semiconductor die provided with a die alignment mark; and a camera that images a main surface of the die on which the die alignment mark is formed or a main surface of a substrate on which a substrate alignment mark is formed, via a covering member that covers the die alignment mark or the substrate alignment mark, the mounting program causing a computer to function as: a first imaging functional unit that obtains a first image by imaging the main surface of the die or the main surface of the substrate; a first extraction functional unit that extracts the die alignment mark or the substrate alignment mark from the first image; a standby functional unit that waits until a predetermined time elapses when the extraction of the die alignment mark or the substrate alignment mark fails as a result of the operation of the first extraction functional unit; a second imaging functional unit that obtains a second image by imaging the main surface of the die or the main surface of the substrate again after the operation of the standby functional unit; and a second extraction functional unit that extracts the die alignment mark or the substrate alignment mark from the second image.

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