Die Bonding Apparatus and Method for Manufacturing a Semiconductor Device

Abstract

To provide a technique capable of improving the uniformity of imaging conditions of a plurality of imaging objects.SOLUTION: A die bonding device comprises: a plurality of imaging devices which are stationarily arranged in one row along the width direction of a base plate on a stage that supports the base plate from below; a plurality of reference marks which are provided on the stage or in the vicinity of the outer side of the stage in the plan view; and a control unit which is configured to make the plurality of imaging devices to image a plurality of imaging objects located in one row along the width direction on the substrate. The control unit is configured to acquire an image by imaging the plurality of reference marks respectively by the plurality of imaging devices, perform image conversion such that the acquired image becomes a prescribed image, and store a parameter when the image conversion is performed.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present disclosure relates to a die bonding apparatus, and is applicable, for example, to a die bonder that images an attachment area with a plurality of recognition cameras.

Background Art

[0002] A die bonder as a die bonding apparatus bonds (places and adheres) a semiconductor chip (hereinafter simply referred to as a die) onto a substrate such as a wiring board or a lead frame or an already bonded die using a resin paste, solder, gold plating, etc. as a bonding material. For example, in a die bonder that bonds a die to the surface of a substrate, the die is sucked and picked up from a wafer using a suction nozzle called a collet attached to the tip of a bonding head, placed at a predetermined position on the substrate, a pressing force is applied, and bonding is performed by heating the bonding material. Such an operation (work) is repeatedly performed.

[0003] For example, when using a resin as a bonding material, resin pastes such as silver (Ag) epoxy and acrylic are used as adhesives (hereinafter referred to as paste adhesives). The paste adhesive for bonding the die to the substrate is enclosed in a syringe, and this syringe moves up and down with respect to the substrate to inject and apply the paste adhesive. That is, the paste adhesive is applied in a predetermined amount at a predetermined position by a syringe containing the paste adhesive, and the die is pressure-bonded and baked on the paste adhesive to be adhered. A recognition camera (preform camera) is attached near the syringe, and this recognition camera confirms the position where the paste adhesive is applied for positioning and also confirms whether the applied paste adhesive is applied in a predetermined shape and in a predetermined amount at a predetermined position.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] When imaging a plurality of imaging objects with a single imaging device, an imaging object that is far from directly below the imaging device may be imaged obliquely, resulting in a decrease in the accuracy of positioning or appearance inspection.

[0006] An object of the present disclosure is to provide a technology capable of improving the uniformity of imaging conditions for a plurality of imaging objects. Other problems and novel features will become apparent from the description of this specification and the accompanying drawings.

MEANS FOR SOLVING THE PROBLEMS

[0007] The outline of a typical example of the present disclosure is briefly described as follows. That is, a die bonding apparatus includes a plurality of imaging devices fixedly arranged in a row along the width direction of a substrate above a stage that supports the substrate from below, a plurality of reference marks provided on the stage itself or in the vicinity outside the stage in a plan view, and a control unit configured to image a plurality of imaging objects located in a row along the width direction on the substrate with the plurality of imaging devices. The control unit is configured to image the plurality of reference marks with each of the plurality of imaging devices to obtain an image, perform image conversion so that the obtained image becomes a predetermined image, and save parameters when the image conversion is performed.

EFFECTS OF THE INVENTION

[0008] According to the die bonding apparatus, it is possible to improve the uniformity of imaging conditions for a plurality of imaging objects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]

Figure 1

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Figure 14

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. However, in the following description, the same reference numerals may be given to the same components and repeated descriptions may be omitted. Note that the drawings may schematically show the widths, thicknesses, shapes, etc. of each part compared to the actual aspects for clearer explanation, but this is only an example and does not limit the interpretation of the present disclosure.

[0011] The configuration of the die bonder in the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a top view showing the outline of the die bonder in the embodiment. FIG. 2 is a diagram for explaining the operations of the pickup head and the bonding head when viewed from the direction of arrow A in FIG. 1.

[0012] The die bonder 10 generally includes a die supply unit 1 that supplies a die D to be mounted on a substrate S, a pickup unit 2, an intermediate stage unit 3, a preform unit 9, a bonding unit 4, a transfer unit 5, a substrate supply unit 6, a substrate discharge unit 7, and a control unit 8 that monitors and controls the operations of each unit. The Y-axis direction is the front-rear direction of the die bonder 10, and the X-axis direction is the left-right direction. The die supply unit 1 is disposed on the front side of the die bonder 10, and the bonding unit 4 is disposed on the back side. Here, a plurality of product areas (hereinafter referred to as attachment areas P) that will become the final package are formed on the substrate S. For example, when the substrate S is a lead frame, the attachment area P has tabs on which the die D is placed.

[0013] First, the die supply unit 1 supplies the die D to be mounted on the attachment area P of the substrate S. The die supply unit 1 includes a wafer holding stage 12 that holds a wafer 11 and a peeling unit 13 shown by a dotted line that pushes up the die D from the wafer 11. The die supply unit 1 is moved in the XY-axis directions by a driving means (not shown) and moves the die D to be picked up to the position of the peeling unit 13.

[0014] The pickup unit 2 includes a pickup head 21 that picks up the die D, a Y drive unit 23 of the pickup head that moves the pickup head 21 in the Y-axis direction, drive units (not shown) that move the collet 22 up and down, rotate it, and move it in the X-axis direction, and a wafer recognition camera 24 that grasps the pickup position of the die D picked up from the wafer 11. The pickup head 21 has a collet 22 that sucks and holds the pushed-up die D at its tip, picks up the die D from the die supply unit 1, and places it on the intermediate stage 31. The pickup head 21 has drive units (not shown) that move the collet 22 up and down, rotate it, and move it in the X-axis direction.

[0015] The intermediate stage portion 3 includes an intermediate stage 31 for temporarily placing the die D thereon, and a stage recognition camera 32 for recognizing the die D on the intermediate stage 31.

[0016] The preform portion 9 includes a syringe 91, a drive unit 93 for moving the syringe 91 in the Y-axis direction and the vertical direction, a preform camera 94 as an imaging device for grasping the application position and the like of the syringe 91, and a preform stage 130. The preform stage 130 is raised when applying the paste-like adhesive to the substrate S and supports the substrate S from below. The preform stage 130 has suction holes (not shown) for vacuum-sucking the substrate S and can fix the substrate S. Details of the preform camera 94 will be described later. The syringe 91 is transported to the substrate S transported to the preform stage 130 by the transport unit 5 and applies a paste-like adhesive such as an epoxy resin to the substrate S. The syringe 91 has the paste-like adhesive sealed therein and is configured such that the paste-like adhesive is extruded from the nozzle tip and applied to the substrate S by air pressure. When the substrate S is, for example, a multi-connected lead frame in which a plurality of unit lead frames are arranged in a horizontal row and continuously connected in series, the syringe 91 applies the paste-like adhesive to each tab of the unit lead frame.

[0017] The bonding portion 4 includes a bonding head 41 provided with a collet 42 for sucking and holding the die D at its tip, similar to the pickup head 21, a Y drive unit 43 for moving the bonding head 41 in the Y-axis direction, and a substrate recognition camera 44 for imaging a position recognition mark (not shown) of the attachment region P of the substrate S and recognizing the bonding position. With such a configuration, the bonding head 41 corrects the pickup position and posture based on the imaging data of the stage recognition camera 32, picks up the die D from the intermediate stage 31, and bonds the die D onto the attachment region P where the paste-like adhesive of the substrate S being transported is applied based on the imaging data of the substrate recognition camera 44.

[0018] The transfer unit 5 has a substrate transfer claw 51 that grips and transfers the substrate S, and a transfer lane (shoot) 52 as a transfer path along which the substrate S moves. The substrate S is moved, for example, by driving a nut (not shown) of the substrate transfer claw 51 provided in the transfer lane 52 with a ball screw (not shown) provided along the transfer lane 52. With such a configuration, the substrate S moves from the substrate supply unit 6 along the transfer lane 52 to the bonding position, and after bonding, moves to the substrate discharge unit 7 and delivers the substrate S to the substrate discharge unit 7.

[0019] Next, the configuration of the die supply unit 1 will be described with reference to FIG. 3. FIG. 3 is a schematic cross-sectional view showing the main part of the die supply unit shown in FIG. 1.

[0020] The die supply unit 1 includes a wafer holding stage 12 that moves in the horizontal direction (within the XY plane) and a peeling unit 13 that moves in the vertical direction. The wafer holding stage 12 has an expand ring 15 that holds the wafer ring 14 and a support ring 17 that horizontally positions the dicing tape 16 fixed to the wafer ring 14. The dice D diced in a mesh pattern on the wafer 11 are adhesively fixed to the dicing tape 16. The peeling unit 13 is disposed inside the support ring 17.

[0021] When pushing up the die D, the die supply unit 1 lowers the expand ring 15 that holds the wafer ring 14. As a result, the dicing tape 16 held by the wafer ring 14 is stretched, the interval between the dice D is widened, and the peeling unit 13 pushes up or horizontally moves the dicing tape 16 from below the dice D, improving the pick-up property of the dice D.

[0022] The control system of the die bonder 10 will be described with reference to FIG. 4. FIG. 4 is a block diagram showing the schematic configuration of the control system of the die bonder shown in FIG. 1.

[0023] As shown in FIG. 4, the control system 80 includes a control unit 8, a drive unit 86, a signal unit 87, and an optical system 88. The control unit 8 mainly includes a control and arithmetic unit 81 mainly composed of a CPU (Central Processing Unit), a storage device 82, an input / output device 83, a bus line 84, and a power supply unit 85. The storage device 82 includes a main storage device 82a composed of a RAM (Random Access Memory) or the like that stores processing programs and the like, and an auxiliary storage device 82b composed of an HDD (Hard Disk Drive) or the like that stores control data, image data, and the like necessary for control. The input / output device 83 includes a monitor 83a that displays the device state, information, etc., a touch panel 83b for inputting the operator's instructions, a mouse 83c for operating the monitor, and an image capture device 83d for capturing image data from the optical system 88. Further, the input / output device 83 includes a motor control device 83e that controls the drive unit 86 such as the XY table (not shown) of the die supply unit 1 and the ZY drive axis of the bonding head table, and an I / O signal control device 83f that captures or controls signals from the signal unit 87 such as various sensor signals and switches such as lighting devices. The optical system 88 includes the wafer recognition camera 24, the preform camera 94, the stage recognition camera 32, and the substrate recognition camera 44 shown in FIG. 1 or FIG. 2. The control and arithmetic unit 81 fetches and calculates necessary data via the bus line 84, and controls the bonding head 41 and the like, and sends information to the monitor 83a and the like.

[0024] The control unit 8 stores the image data captured by the optical system 88 via the image capture device 83d in the storage device 82. Based on the stored image data, software programmed using the control and arithmetic unit 81 is used to position the die D and the substrate S, inspect the coating pattern of the paste-like adhesive, and inspect the surfaces of the die D and the substrate S. Based on the positions of the die D and the substrate S calculated by the control and arithmetic unit 81, the driving unit 86 is moved via the motor control device 83e by software. Through this process, the die D on the wafer 11 is positioned, and the die D is bonded onto the substrate S by operating the driving units of the die supply unit 1 and the die bonding unit 4. The recognition camera used in the optical system 88 is a grayscale camera, a color camera, etc., and quantifies the brightness (light intensity).

[0025] Next, a method for manufacturing a semiconductor device using the die bonder according to the embodiment will be described with reference to FIG. 5. FIG. 5 is a flowchart showing the method for manufacturing a semiconductor device using the die bonder shown in FIG. 1.

[0026] (Step S51: Wafer / Substrate Loading Process) The wafer ring 14 holding the dicing tape 16 to which the die D divided from the wafer 11 is attached is stored in a wafer cassette (not shown) and carried into the die bonder 10. The control unit 8 supplies the wafer ring 14 from the wafer cassette filled with the wafer ring 14 to the die supply unit 1. Also, the substrate S is prepared and carried into the die bonder 10. The control unit 8 attaches the substrate S to the substrate transfer claw 51 at the substrate supply unit 6.

[0027] (Step S52: Pickup Process) The control unit 8 moves the wafer ring 14 so that the desired die D can be picked up from the wafer ring 14 by the wafer holding stage 12, and performs positioning and surface inspection based on the data imaged by the wafer recognition camera 24. The control unit 8 peels the positioned die D from the dicing tape 16 by the peeling unit 13. In parallel with this, the control unit 8 lowers the pickup head 21 directly above the die D to be picked up, and vacuum-sucks the die D peeled from the dicing tape 16 by the collet 22 of the pickup head 21. Then, the control unit 8 performs an ascending operation, a parallel movement operation, and a descending operation of the pickup head 21 to place the die D at a predetermined position on the intermediate stage 31. At this time, the control unit 8 sucks the die D by suction holes (not shown) of the intermediate stage 31 and separates it from the pickup head 21. In this way, the die D peeled from the dicing tape 16 is adsorbed and held by the collet 22, transported to the intermediate stage 31, and placed thereon.

[0028] The control unit 8 images the die D on the intermediate stage 31 by the stage recognition camera 32, performs positioning of the die D, and performs a surface inspection. The control unit 8 calculates the amount of deviation (in the X, Y, and θ directions) of the die D on the intermediate stage 31 from the die position reference point of the die bonder by image processing. The die position reference point is held in advance as a predetermined position of the intermediate stage 31 in the initial setting of the apparatus. Then, the control unit 8 performs a surface inspection of the die D by image processing.

[0029] Then, the control unit 8 returns the pickup head 21 that has transported the die D to the intermediate stage 31 to the die supply unit 1. According to the above-described procedure, the next die D is peeled from the dicing tape 16, and thereafter, the die Ds are peeled one by one from the dicing tape 16 according to the same procedure.

[0030] (Step S53: Bonding process) The control unit 8 conveys the substrate S to the preform stage 130 by the conveyance unit 5. The control unit 8 acquires an image of the surface of the substrate S before coating by the preform camera 94 and confirms the surface on which the paste adhesive is to be applied. If there is no problem with the surface to be coated, the control unit 8 applies the paste adhesive from the syringe 91 to the substrate S supported by the preform stage 130. When the substrate S is a multi-strip lead frame, the paste adhesive is applied to all tabs. The control unit 8 re-checks with the preform camera 94 whether the paste adhesive has been accurately applied after coating and inspects the applied paste adhesive.

[0031] If there is no problem with the coating, the control unit 8 conveys the substrate S to the bonding stage BS by the conveyance unit 5. Then, the control unit 8 images the substrate S supported by the bonding stage BS with the substrate recognition camera 44. The control unit 8 calculates the amount of deviation (in the X, Y, and θ directions) of the substrate S from the substrate position reference point of the die bonder by image processing. The substrate position reference point is held in advance as a predetermined position of the substrate check unit in the initial setting of the apparatus.

[0032] The control unit 8 corrects the adsorption position of the bonding head 41 from the amount of deviation of the die D calculated in step S52 and adsorbs the die D by the collet 42. The bonding head 41 that has adsorbed the die D from the intermediate stage 31 is raised, translated, and lowered to attach the die D to a predetermined location of the substrate S supported by the bonding stage BS. Then, the control unit 8 performs inspections such as whether the die D has been bonded to the desired position based on the image data imaged by the substrate recognition camera 44.

[0033] (Step S54: Substrate unloading process) The control unit 8 conveys the substrate S to which the die D has been bonded to the substrate unloading unit 7. The control unit 8 takes out the substrate S to which the die D has been bonded from the substrate conveyance claws 51 in the substrate unloading unit 7. The substrate S is unloaded from the die bonder 10.

[0034] As described above, die D is mounted on substrate S and carried out from the die bonder. Thereafter, it is electrically connected to the electrodes of substrate S via Au wires or the like in the wire bonding process. Thereafter, substrate S is conveyed to the molding process, and the die D and the Au wires are sealed with a molding resin (not shown), thereby completing the package.

[0035] In the present embodiment, the preform camera 94 is used for appearance inspection of the paste-like adhesive or the like. First, problems of cameras such as the preform camera 94 will be described in order to make the present embodiment clearer.

[0036] Generally, when the number of pixels of a camera is constant, if the field of view size is increased by a lens, the pixel resolution increases. Therefore, when the size of substrate S increases and the field of view size is increased accordingly, the pixel resolution of the camera increases, and the resolution is insufficient for appearance inspection.

[0037] Also, when the field of view size is increased (to a wide field of view) by a macro lens which is a non-telecentric lens, when the subject (imaging object) is a three-dimensional object such as a paste-like adhesive, the area of the imaging object differs between the object directly under the camera (lens) and the object at the edge of the field of view, or the side surface of the object at the edge of the field of view can be seen. Since a telecentric lens condenses parallel light, the side surface cannot be seen in all imaging objects. However, it is necessary to increase the size of the lens, and the focal length also becomes longer accordingly. Mounting such a large lens on a die bonding apparatus is not preferable from the viewpoint of efficiency.

[0038] By dividing the field of view covering the entire width direction of substrate S and viewing it with a plurality of cameras (lenses), the lens magnification per unit can be increased, and the pixel resolution can be improved. By installing the camera (lens) directly above the application position of the paste-like adhesive, the appearance can be made more uniform even with a macro lens.

[0039] Therefore, in order to improve pixel resolution, image the paste-like adhesive as a three-dimensional object directly above it, and reduce the measurement area error, it was considered to configure the preform camera 94 in this embodiment by arranging a plurality of cameras side by side (multi-camera configuration). Here, for the sake of simplicity, it is assumed that the applied paste-like adhesive as the imaging object has a rectangular shape.

[0040] The multi-camera configuration will be described with reference to FIG. 6. FIG. 6 is a diagram showing an ideal case of a plurality of cameras in the multi-camera configuration. FIG. 6(a) is a perspective view showing the cameras and the imaging object, FIG. 6(b) is a diagram showing the imaging images of each camera, and FIG. 6(c) is a diagram showing a composite image obtained by simply connecting the images in FIG. 6(b).

[0041] For example, as shown in FIG. 6(a), a plurality of cameras 101 to 103 are fixedly arranged in a row in the width direction (Y-axis direction) of the substrate S above the substrate S. These cameras 101 to 103 are at the same height and are spaced apart by a predetermined interval in the horizontal direction, and the optical axes of each of the cameras 101 to 103 are parallel to each other and perpendicular to the substrate S. Lenses 111 to 113 are attached to each of the cameras 101 to 103. The imaging fields of adjacent cameras overlap. Here, the substrate S is, for example, rectangular and flat, and a large number of attachment regions are provided vertically and horizontally. In FIG. 6(a), an example in which three attachment regions are provided in a row of the substrate S is shown, and three imaging objects OB1, OB2, and OB3 are shown. Note that one coaxial illumination (not shown) is provided below the cameras 101 to 103 (lenses 111 to 113).

[0042] Each of the cameras 101 to 103 simultaneously (in parallel) images the imaging objects OB1, OB2, and OB3, respectively. Further, by transporting the substrate S in the transport direction (X-axis direction) by the transport lane 52, the imaging objects in the remaining rows are sequentially imaged. By using the multi-camera configuration, imaging can be performed almost directly above the imaging object, and inspection can be performed with improved uniformity. In addition, by using the multi-camera configuration, there is no need to move the camera, and the same processing efficiency as that of a wide-field optical system can be obtained.

[0043] In a multi-camera system, the images output from each of the cameras 101 to 103 shown in Fig. 6(b) are combined into a single large image and treated in the same coordinate system as shown in Fig. 6(c).

[0044] However, there are the following problems with multi-camera systems. (A) When multiple cameras have respective mounting errors (X, Y, Z, θ, orientation), simply connecting the images will result in distortion in the composite image. (B) When there are differences in camera sensitivity and individual differences in lenses, differences in brightness will occur between the output images even when the same object is imaged. Since appearance inspections such as for paste-like adhesives are performed based on the brightness of the images, errors will occur with different cameras and lenses with individual differences, and high-precision images cannot be obtained.

[0045] The problem in (A) above will be explained with reference to Fig. 7. Fig. 7 is a diagram showing a case where multiple cameras are not ideal in a multi-camera system. Fig. 7(a) is a perspective view showing the cameras and the imaging target, Fig. 7(b) is a diagram showing the imaging images of each camera, and Fig. 7(c) is a diagram showing a composite image obtained by simply connecting the images in Fig. 7(b).

[0046] For example, in Fig. 7(a), camera 101 has mounting errors in the position in the X-axis direction (X position), the position in the Y-axis direction (Y position), the position in the Z-axis direction (Z position), and the position in the θ direction (rotation), camera 102 has a mounting error in which the orientation (optical axis) is tilted, and camera 103 is ideal and has no mounting error. As a result, as shown in Fig. 7(b), the image of camera 101 is shifted to the upper left and rotated to the left, the image of camera 102 is shifted to the right and becomes a trapezoidal image, and the image of camera 103 becomes an image similar to Fig. 6. Simply connecting these images results in a composite image as shown in Fig. 7(c), which is different from the composite image shown in Fig. 6(c).

[0047] Therefore, in the present embodiment, in order to solve the above-described problem (A), correction data is acquired using reference marks provided on a stage such as the preform stage 130 at the time of shipment or adjustment (imitation operation) of the die bonder 10. By using this correction data, it is possible to more easily improve the accuracy of image synthesis of images captured by a plurality of cameras as an imaging device.

[0048] First, a method for correcting the mounting error of the camera (mounting error correction process) will be described with reference to FIGS. 8 to 10. FIG. 8 is a top view showing a preform stage having reference marks. FIG. 9 is a side view showing the camera and the preform stage. FIG. 10 is a diagram for explaining the mounting error correction process, FIG. 10(a) is a diagram showing the field of view of each camera and the preform stage, FIG. 10(b) is a diagram showing an image captured by each camera, FIG. 10(c) is a diagram showing a converted image, and FIG. 10(d) is a diagram showing a synthesized image.

[0049] As shown in FIG. 8, the preform stage 130 is rectangular in plan view. Reference marks MK are provided by precisely engraving or drilling holes at the peripheral portion of the preform stage 130. The reference marks MK enter four points each into the fields of view IA1 to IA3 of the cameras 101 to 103, and since the fields of view of adjacent cameras overlap, the reference marks MK are formed on the preform stage 130 so that two reference marks MK enter each overlapping portion of the fields of view of adjacent cameras. When there are three cameras, eight reference marks MK are formed on the preform stage 130. The reference marks MK serve as a reference for the input coordinates necessary for the projective transformation of the images output from the respective cameras 101 to 103. The preform stage 130 having the reference marks functions as a jig for mounting error correction.

[0050] As shown in Fig. 9, the control unit 8 images the preform stage 130 at positions where four reference marks MK enter each of the fields of view IA1 to IA3 of the cameras 101 to 103. Here, as shown in Fig. 10(a), there are mounting errors in the cameras 101 and 102. The camera 101 is mounted shifted to the left in the X-axis direction, and the camera 102 is mounted rotated to the right (clockwise) when viewed from above. There is no mounting error in the camera 103. As a result, the images P110, P120, and P130 of the preform stage 130 captured by the cameras 101 to 103 become the images shown in Fig. 10(b). For example, the image P110 is an image in which the preform stage 130 is imaged shifted to the right in the X-axis direction with respect to the field of view IA1 of the camera 101.

[0051] The control unit 8 detects the positions of the respective reference marks MK in each of the images P110, P120, and P130 shown in Fig. 10(b) by image processing such as labeling or pattern matching. The control unit 8 performs image conversion so as to move the coordinates of the reference mark MK imaged by projective transformation to the coordinates of the four corners of the image (reference coordinates). Thereby, three images P111, P121, and P131 shown in Fig. 10(c) are obtained. Here, projective transformation can perform image conversion from a trapezoid to a rectangle, in addition to translation, rotation, enlargement / reduction, and shear, using a 3x3 matrix. In this embodiment, image conversion is performed from the coordinates of four points of the input image to the coordinates of four points of the output image, and an image taken obliquely can be converted to an image seen from directly above (vertical correction).

[0052] The control unit 8 synthesizes the individual images P111 to P113 shown in Fig. 10(c) to obtain a synthesized image P100 shown in Fig. 10(d). This synthesized image P100 is the same image as the above-described reference image. The control unit 8 calculates and stores the parameters of the image conversion (conversion matrix) in the images of the preform stage 130 captured by the cameras 101 to 103.

[0053] Note that the reference mark MK may not be provided on the preform stage 130, but may be provided in the vicinity outside the preform stage 130 in a plan view. This will be described with reference to FIG. 11. FIG. 11 is a top view showing the preform stage and the reference mark.

[0054] A total of four reference marks MK are provided at two points each on a pair of transfer lanes 52. Further, a total of four reference marks MK are provided at two points each in the vicinity of two sides extending along the Y-axis direction of the preform stage 130. Here, it is preferable to align the heights of the respective reference marks MK. The reference marks MK provided in the vicinity of the two sides of the preform stage 130 preferably have variable heights. This eliminates the need to remove the reference marks as it does not interfere with substrate transfer. The reference marks MK enter four at a time into the respective visual fields IA1 to IA3 of the cameras 101 to 103, and since the visual fields of adjacent cameras overlap, the reference marks MK are arranged such that two reference marks MK enter into the overlapping portion of the visual fields of adjacent cameras.

[0055] Also, in the present embodiment, in order to solve the problem (B) described above, correction data is acquired using the preform stage 130 at the time of shipment or adjustment (imitation operation) of the die bonder 10. By using this correction data, it is possible to more easily improve the accuracy of image synthesis of images captured by a plurality of cameras.

[0056] Next, a method of adjusting sensitivity (sensitivity error correction process) by correcting the gain of the camera will be described with reference to FIG. 12. FIG. 12 is a conceptual diagram for explaining the sensitivity error correction process of the camera, FIG. 12(a) is a composite image before correcting the gain value of the camera, and FIG. 12(b) is a composite image after correcting the gain value of the camera.

[0057] The surface of the preform stage 130 is processed to have a uniform reflectance and is used to correct brightness. As a process for making the reflectance uniform, for example, the surface of the preform stage 130 is colored. This color is preferably the same as the irradiation light color of the lighting device during correction (imitation operation). It is preferable to change the irradiation light color during the imitation operation and the irradiation light color during the production operation. However, the color of the surface of the preform stage 130 is preferably other than metallic color and white and different from the irradiation light color during the production operation. This is because when the color of the surface of the preform stage 130 is metallic color or white, etc., it is difficult to distinguish the outline of the lead frame when the substrate is a lead frame. For this reason, the color of the surface of the preform stage 130 is a color other than metallic color and white, and light of a color different from that color is irradiated during the production operation. In this case, the preform stage 130 becomes black, and the lead frame is recognized as the same color as the irradiation light color. Thereby, even if the substrate is a lead frame, its outline can be recognized. Note that since the surface of the preform stage deteriorates during production, for example, due to sliding, recoloring may be performed during production.

[0058] The preform stage 130 functions as a jig for sensitivity error correction that serves as a reference for adjusting the output levels of the cameras 101 to 103. The control unit 8 simultaneously images the preform stage 130 with the cameras 101 to 103. Then, the control unit 8 calculates the average output from the output values indicating the brightness of a plurality of pixels in the central portion of each image output from the cameras 101 to 103. Here, the central portion is, for example, a region where the fields of view of adjacent cameras do not overlap, that is, a region where the reference mark MK is not provided on the preform stage 130 and is not a peripheral region. When the preform stage FS has suction holes for vacuum-sucking the substrate S in the central portion, image processing is performed to eliminate the influence of the reflectance due to the suction holes. The control unit 8 identifies the camera with the highest output value (the brightest camera) based on the average output level. The control unit 8 calculates and sets (adjusts) the gain value of the cameras other than the brightest camera so that they have the same output level as the brightest camera. There are two types of gain: analog gain and digital gain. The former means amplifying the charge in the process of converting the light exposed by the image sensor into charge, and the latter means increasing the value obtained by software calculation. Either gain adjustment may be used.

[0059] For example, in FIG. 12(a), the image P32 captured by the camera 102 appears darker than the images P31 and P33 captured by the cameras 101 and 103. Also, the image P31 captured by the camera 101 appears darker than the image P33 captured by the camera 103. Therefore, by adjusting the gain values of the cameras 101 and 102 so that they have the same luminance value as the image P33 captured by the camera 103, a composite image as shown in FIG. 12(b) can be obtained. Here, the correction target is only the camera or lens factor.

[0060] Next, the image synthesis during the production operation of the die bonder 10 will be described with reference to FIGS. 13 and 14. FIG. 13 is a side view showing the camera and the substrate. FIG. 14 is a diagram for explaining the image synthesis method. FIG. 14(a) is a diagram showing the field of view of each camera and the imaging object, FIG. 14(b) is a diagram showing the images captured by each camera, FIG. 14(c) is a diagram showing the converted images, and FIG. 14(d) is a diagram showing the synthesized image.

[0061] The control unit 8 conveys the substrate S by the conveyance unit 5 and places it on the preform stage 130 so as to enter the fields of view of the cameras 101 to 103 as shown in FIG. 13. Then, the control unit 8 images the imaging objects OB1 to OB3 by the cameras 101 to 103. Here, the gains of the cameras 101 to 103 are adjusted by the sensitivity error correction process described above. As shown in FIG. 14(a), similar to FIG. 10(a), there are mounting errors in the cameras 101 and 102. The camera 101 is mounted shifted to the left in the X-axis direction, and the camera 102 is mounted rotated clockwise when viewed from above. As a result, the images P210, P220, and P230 of the imaging objects OB1 to OB3 captured by the cameras 101 to 103 become the images shown in FIG. 14(b).

[0062] Then, the control unit 8 performs image conversion by perspective transformation using the stored image conversion parameters described above, and obtains the images P211, P221, and P231 shown in FIG. 14(c). Thereby, the mounting error of the camera can be canceled. Then, the control unit 8 joins the converted images together to obtain one image (synthesized image P200) shown in FIG. 14(d), and performs subsequent processing (positioning, appearance inspection) on the synthesized image P200.

[0063] According to the present embodiment, it has one or more of the following effects.

[0064] (1) Images captured by a plurality of cameras can be managed at the same magnification and the same coordinates with a simpler device configuration (reference marks provided on a stage or the like as a jig for correcting mounting errors).

[0065] (2) Images captured by multiple cameras can be managed at the same level of brightness with a simpler device configuration (a stage as a jig for sensitivity error correction).

[0066] (3) By splitting and viewing with multiple cameras (lenses), the lens magnification per camera can be increased, and the pixel resolution can be improved.

[0067] (4) A three-dimensional object can be projected almost directly below the camera (lens), and the side surface of the three-dimensional object can be prevented from being projected.

[0068] (5) The positioning accuracy of the imaging object can be stabilized, and the appearance inspection can also be stabilized.

[0069] As described above, the invention made by the present inventors has been specifically described based on the embodiments. However, it goes without saying that the present disclosure is not limited to the above embodiments and can be variously modified.

[0070] For example, in the embodiment, the number of reference marks MK within the field of view of each camera was described with four examples, but it may be five or more.

[0071] Also, in the embodiment, an example of providing the reference mark MK was described, but instead of the reference mark MK, a line extending along the four sides within the field of view of each camera may be used.

[0072] Also, in the embodiment, an example of projective transformation as image conversion was described, but affine transformation may be used.

[0073] Also, in the embodiment, the surface of the preform stage is colored. Although an example of making the color the same as the irradiation light color during the imitation operation and changing the irradiation light color during the imitation operation and the production operation has been described, a phosphor may be applied to the surface of the preform stage, and UV (ultraviolet) light may be used as the irradiation light during the imitation operation and the production operation. As a result, since the phosphor on the surface of the preform stage irradiated with UV light is excited and emits light, it becomes possible to adjust the camera. Also, during the production operation, the silhouette of the lead frame can be confirmed among the emission colors of the phosphor. Note that since the surface of the preform stage deteriorates during production, for example, due to sliding, re-application may be performed during production.

[0074] Also, in the embodiment, an example of applying a paste-like adhesive to the substrate at the preform section has been described, but the adhesive for bonding the die to the substrate may be a film-like adhesive material called a die attach film (DAF) that is pasted between the wafer 11 and the dicing tape 16 instead of the paste-like adhesive applied by the syringe 91. The DAF is suitable for a stacked package in which a plurality of dies are placed on a die on the substrate S. In this case, the substrate recognition camera is made multi-row in the same manner as the preform camera, and correction is performed using a reference mark provided on a bonding stage or the like as a jig for correcting mounting errors and a bonding stage as a jig for correcting sensitivity errors. Also, in this case, the substrate or the die placed on the substrate may be washed in the preform section.

[0075] Also, in the embodiment, an intermediate stage section 3 is provided between the die supply section 1 and the bonding section 4, and the die D picked up from the die supply section 1 by the pickup head 21 is placed on the intermediate stage 31, and the die D is picked up again from the intermediate stage 31 by the bonding head 41 and bonded to the conveyed substrate S. However, the die D picked up from the die supply section 1 by the bonding head 41 may be bonded to the substrate S.

Explanation of Reference Numerals

[0076] 8 ··· Control unit 10 ··· Die bonder (die bonding apparatus) 101~103 ··· Camera (imaging device) 130 ··· Preform stage (stage) OB1~OB3 ··· Objects to be imaged S ··· Substrate

Claims

1. A stage that supports a substrate from below, a plurality of reference marks provided on the stage itself or in the vicinity of the outside of the stage in a plan view, a plurality of imaging devices fixedly arranged in a row along the width direction of the substrate above the stage, a control unit configured to image a plurality of imaging objects located in a row along the width direction on the substrate with the plurality of imaging devices, comprising: the control unit, images the plurality of reference marks with each of the plurality of imaging devices to obtain an image, performs image conversion so that the obtained image becomes a predetermined image, saves the parameters when performing the image conversion, the control unit further, detects the position of the imaged reference mark by image processing, moves the coordinates of the reference mark imaged by projective transformation to reference coordinates located at the four corners of the image, A die bonding apparatus configured to save the parameters of the transformation matrix used for the projective transformation.

2. In the die bonding apparatus according to Claim 1, the plurality of reference marks enter four points into each of the fields of view of the plurality of imaging devices, and are formed on the stage so that two points enter each in a portion where the fields of view of adjacent imaging devices overlap. A die bonding apparatus.

3. In the die bonding apparatus according to Claim 1, the control unit is further configured to bond a die to the substrate by a bond head. A die bonding apparatus.

4. In the die bonding apparatus according to Claim 1, the control unit, performs projective transformation on each of the obtained images of the plurality of imaging objects with the parameters, A die bonding apparatus configured to splice the projective-transformed images together to generate a composite image.

5. In the die bonding apparatus according to Claim 1, the control unit, images the stage with each of the imaging devices to obtain an image, A die bonding apparatus configured to adjust the gain value of the imaging device based on the obtained image.

6. In the die bonding apparatus according to Claim 5, the control unit, calculates the brightness of the imaging device based on the average value of the brightness at the center of each image obtained by imaging the stage, identifies the brightest imaging device based on the calculated brightness, and adjusts the gain values of other imaging devices so that they have the same brightness as the identified imaging device. A die bonding apparatus.

7. In the die bonding apparatus according to claim 1, the plurality of reference marks enter four points into each of the fields of view of the plurality of imaging devices, and are provided near the stage so as to enter two points each into a portion where the fields of view of adjacent imaging devices overlap. A die bonding apparatus.

8. In the die bonding apparatus according to any one of claims 1 to 7, the control unit is configured to convey the substrate in the length direction of the substrate and image a plurality of attachment regions in the next row with the plurality of imaging devices. A die bonding apparatus.

9. In the die bonding apparatus according to any one of claims 1 to 7, the imaging object is a paste-like adhesive applied to the substrate. A die bonding apparatus.

10. In the die bonding apparatus according to claim 9, the control unit is configured to perform an appearance inspection of the paste-like adhesive applied to the substrate by the imaging device. A die bonding apparatus.

11. A stage that supports the substrate from below, a plurality of reference marks provided on the stage itself or provided in the vicinity outside the stage in a plan view, and a plurality of imaging devices fixedly arranged in a row along the width direction of the substrate above the substrate, and imaging the stage by each of the imaging devices to obtain an image, adjusting the gain value of the imaging device based on the obtained image, imaging the plurality of reference marks by each of the plurality of imaging devices with the adjusted gain value to obtain an image, performing image conversion so that the obtained image becomes a predetermined image, and a control unit configured to store parameters when performing the image conversion, and a step of loading a substrate into the die bonding apparatus, imaging an imaging object of a plurality of attachment regions in a row along the width direction located on the substrate with the plurality of imaging devices to obtain a plurality of images, generating a composite image based on the obtained plurality of images, and recognizing the imaging object based on the composite image; conveying the substrate in the length direction of the substrate and imaging a plurality of attachment regions in the next row with the plurality of imaging devices; detecting the position of the imaged reference mark by image processing, moving the coordinates of the reference mark imaged by projective transformation to reference coordinates located at the four corners of the image, and storing parameters of the transformation matrix used for the projective transformation; A method for manufacturing a semiconductor device comprising:

12. In the method of manufacturing a semiconductor device according to claim 11, Furthermore, a method of manufacturing a semiconductor device comprising a step of bonding a die to the substrate.

13. In the method of manufacturing a semiconductor device according to claim 11, Furthermore, a method of manufacturing a semiconductor device comprising a step of performing projective transformation on each of the acquired images of the plurality of imaging objects by the parameters, and generating a composite image by connecting the projectively transformed images.

14. In the method of manufacturing a semiconductor device according to claim 11, Furthermore, a method of manufacturing a semiconductor device comprising a step of calculating the brightness of the imaging device based on the average value of the brightness of the central portion of each image obtained by imaging the stage, identifying the brightest imaging device based on the calculated brightness, and adjusting the gain value of other imaging devices so as to have the same brightness as the identified imaging device.

15. In the method of manufacturing a semiconductor device according to any one of claims 11 to 14, Furthermore, a step of applying a paste-like adhesive to the substrate is provided, wherein the imaging object is the applied paste-like adhesive.

Images