Chip mounting device and method for manufacturing semiconductor device

Abstract

The present invention relates to a chip mounting device and a method for manufacturing a semiconductor device, and provides a technology capable of distinguishing and identifying cracks and scratches. The chip mounting device includes: a camera that photographs a bare chip; an illumination device that irradiates light to the bare chip at an angle inclined at a predetermined angle relative to the optical axis of the camera; and a control unit that controls the camera and the illumination device. The control unit is configured to change the irradiation direction of the illumination light from the illumination device in the horizontal direction, photograph a plurality of the bare chips through the camera, and identify whether it is a crack or a scratch based on the brightness change of the flaw formed on the bare chip in the photographed image.

Description

Technical Field

[0001] The present invention relates to a die mounting device and can be applied to, for example, a die mounting device that performs surface inspection of a bare chip. Background Art

[0002] As part of the manufacturing process of semiconductor devices, there is a process of mounting a semiconductor chip (hereinafter referred to as a bare chip) on a wiring substrate or a lead frame (hereinafter referred to as a substrate) and assembling a package; as part of the assembly and packaging process, there is a process of dividing a bare chip from a semiconductor wafer (hereinafter referred to as a wafer) (a dicing process) and a mounting process of mounting the divided bare chip on a substrate. The semiconductor manufacturing device used in the mounting process is a chip mounting device such as a chip mounter.

[0003] Sometimes scratches are produced on the bare chip in the process before the mounting process, such as the cutting process. For example, Japanese Patent Gazette No. 2020-13841 (Patent Document 1) discloses the following technology: When an abnormality on the surface of the bare chip is detected by camera-based shooting through a dark field method (oblique light illumination is performed to make the object appear brighter), the captured image is used to determine whether the abnormality is a scratch or caused by a foreign object. The scars on the surface of the bare chip include scratches (scratches) only on the surface of the protective film layer formed by polyimide resins, etc., and scars that penetrate the protective film layer and reach the silicon layer. In this specification, the former is referred to as a scratch and the latter is referred to as a crack.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-13841 Summary of the invention

[0007] Since the crack reaches the circuit area of ​​the bare chip, the component with the crack should be considered as unqualified. On the other hand, in the case of scratches that only protect the surface of the film layer without damaging the circuit area, it is sometimes desirable to consider the component with only the scratch as a qualified product depending on the type of semiconductor product. However, in the case of small scratches that can only be observed with a microscope instead of a shape-destructive scratch that can be easily visually observed, when the scratch on the surface of the bare chip is detected by camera-based shooting using the technology shown in Patent Document 1, it is difficult to use the captured image to determine whether the scratch is a crack or caused by a scratch.

[0008] The object of the present invention is to provide a technique capable of distinguishing and identifying cracks and scratches. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0009] The representative contents of the present invention are briefly described below.

[0010] That is, the chip mounting device includes: an imaging device that images a bare chip; an illumination device that irradiates light to the bare chip at an angle inclined at a predetermined angle relative to the optical axis of the imaging device; and a control unit that controls the imaging device and the illumination device. The control unit is configured to change the irradiation direction of the illumination light from the illumination device in the horizontal direction, and to image a plurality of bare chips by the imaging device, and to identify whether the flaw formed on the bare chip in the captured image is a crack or a scratch based on the brightness change of the flaw.

[0011] Effects of the Invention

[0012] According to the present invention, cracks and scratches can be distinguished and identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic plan view showing a configuration example of a die mounter in the embodiment.

[0014] Figure 2 It is explained in Figure 1 A diagram of the schematic structure when viewed from the direction of arrow A.

[0015] Figure 3 Yes means Figure 1 A schematic cross-sectional view of a main portion of a bare chip supply unit is shown.

[0016] Figure 4 Yes means Figure 1 A block diagram showing a schematic configuration of a control system for a chip mounter is shown.

[0017] Figure 5 Yes Description Figure 1 Flow chart of the die attach process in the die attach machine shown.

[0018] Figure 6 This is a diagram showing the configuration of the lighting device of the substrate recognition camera.

[0019] Figure 7 Yes Description Figure 6 Schematic diagram of the movement of the lighting device shown.

[0020] Figure 8 This is a conceptual diagram illustrating scratches and cracks.

[0021] Fig. 9 (a) is a diagram showing a state where illumination light is irradiated from the upper right side with respect to a scratch. Fig. 9 (b) is a diagram showing a situation where illumination light is irradiated obliquely from above the front side relative to the scratch.

[0022] Fig.10 (a) is a diagram showing a case where illumination light is irradiated from a direction perpendicular to the crack direction and from the upper right side. Fig.10 (b) is a diagram showing a case where illumination light is irradiated from a direction parallel to the cracking direction of the crack and obliquely upward on the front side.

[0023] Fig.11 This is a diagram showing the irradiation direction of illumination light and the brightness of the scratch when a bare chip has a scratch.

[0024] Fig.12 This is a diagram showing the irradiation direction of illumination light and the brightness of the flaw when there is a crack on a bare chip.

[0025] Fig.13 It is a diagram for explaining the lighting device in the first modified example.

[0026] Fig.14 It is a diagram for explaining the lighting device in the second modified example.

[0027] Fig.15 It is a diagram for explaining the lighting device in the third modified example.

[0028] Description of Reference Numerals

[0029] 10: Chip mounter (chip mount device)

[0030] 44: Substrate recognition camera (photographing device)

[0031] 45: Lighting device

[0032] 8: Control Department

[0033] D: Bare chip

[0034] K: Scars

[0035] Kc: Crack

[0036] Ks: Scratches DETAILED DESCRIPTION

[0037] The following is an explanation of the embodiments and modifications using the accompanying drawings. However, in the following description, the same components are sometimes marked with the same reference numerals and repeated descriptions are omitted. In addition, in order to make the description clearer, the drawings sometimes schematically show the width, thickness, shape, etc. of each part compared to the actual form, but this is only an example and does not limit the interpretation of the present invention.

[0038] Figure 1 It is a schematic plan view showing the structure of the die mounter in the embodiment. Figure 2 It is explained in Figure 1A diagram of the schematic structure when viewed from the direction of arrow A.

[0039] The chip mounter 10 generally comprises a bare chip supply unit 1, a pickup unit 2, an intermediate stage unit 3, a mounting unit 4, a conveying unit 5, a substrate supply unit 6, a substrate unloading unit 7, and a control unit 8 for monitoring and controlling the operation of each unit. The Y-axis direction is the front-to-back direction of the chip mounter 10, and the X-axis direction is the left-to-right direction. The bare chip supply unit 1 is arranged at the near front side of the chip mounter 10, and the mounting unit 4 is arranged at the back side. Here, one or more product areas (hereinafter referred to as package areas P) that will eventually become a package are printed on the substrate S.

[0040] The bare chip supply unit 1 has a wafer holding table 12 for holding a wafer 11, and a lifting unit 13 indicated by a dotted line for lifting a bare chip D from the wafer 11. The bare chip supply unit 1 moves in the XY direction by a driving mechanism (not shown) to move the bare chip D to be picked up to the position of the lifting unit 13.

[0041] The pickup unit 2 includes: a pickup head 21 for picking up a bare chip D; a Y driving unit 23 of the pickup head for moving the pickup head 21 in the Y direction; various driving units (not shown) for lifting, rotating, and moving the collet 22 in the X direction; and a wafer recognition camera 24. The pickup head 21 includes a collet 22 for adsorbing and holding the lifted bare chip D at the top end, picking up the bare chip D from the bare chip supply unit 1 and placing it on the intermediate stage 31. The pickup head 21 includes various driving units (not shown) for lifting, rotating, and moving the collet 22 in the X direction.

[0042] The intermediate stage unit 3 includes an intermediate stage 31 on which the bare chip D is temporarily placed, and a stage recognition camera 32 for recognizing the bare chip D on the intermediate stage 31 .

[0043] The mounting section 4 has a mounting head 41, a Y drive section 43, and a substrate recognition camera 44. The mounting head 41 is provided with a collet 42 that adsorbs and holds the bare chip D at the top, similarly to the pickup head 21. The Y drive section 43 moves the mounting head 41 in the Y-axis direction. The substrate recognition camera 44 captures the position recognition mark (not shown) of the packaging area P of the substrate S to recognize the mounting position. The mounting section 4 picks up the bare chip D from the intermediate stage 31, and mounts it on the packaging area P of the conveyed substrate S, or mounts it in the form of stacking on the bare chip already mounted on the packaging area P of the substrate S. According to this structure, the mounting head 41 corrects the picking position / posture based on the shooting data of the stage recognition camera 32, and picks up the bare chip D from the intermediate stage 31. Moreover, the mounting head 41 mounts the bare chip D on the packaging area P of the substrate, or in the form of stacking on the bare chip already mounted on the packaging area P of the substrate S, based on the shooting data of the substrate recognition camera 44.

[0044] The conveying section 5 includes a substrate conveying claw 51 for gripping and conveying the substrate S, and a conveying passage 52 for moving the substrate S. The substrate S is moved by driving a nut (not shown) of the substrate conveying claw 51 provided on the conveying passage 52 using a ball screw (not shown) provided along the conveying passage 52. According to this structure, the substrate S moves from the substrate supply section 6 along the conveying passage 52 to the mounting position, and moves to the substrate unloading section 7 after mounting, and the substrate S is delivered to the substrate unloading section 7.

[0045] The control unit 8 includes a memory storing a program (software) for monitoring and controlling the operation of each part of the die mounter 10 and a central processing unit (CPU) for executing the program stored in the memory.

[0046] Next, use Figure 3 The structure of the bare chip supply unit 1 will be described. Figure 3 Yes means Figure 1 A schematic cross-sectional view of a main portion of a bare chip supply unit is shown.

[0047] The bare chip supply unit 1 includes a wafer holding table 12 that moves in the horizontal direction (XY direction) and a lifting unit 13 that moves in the vertical direction. The wafer holding table 12 includes an expansion ring 15 that holds a wafer ring 14 and a support ring 17 that horizontally positions a dicing tape 16 that is held on the wafer ring 14 and to which a plurality of bare chips D are bonded. The lifting unit 13 is disposed inside the support ring 17.

[0048] The bare chip supply unit 1 lowers the expansion ring 15 holding the wafer ring 14 when lifting the bare chip D. As a result, the dicing tape 16 held by the wafer ring 14 is stretched, causing the interval between the bare chips D to expand, and the bare chip D is lifted from below the bare chip D by the lifting unit 13, thereby improving the pick-up performance of the bare chip D. In addition, as the thinning is reduced, the adhesive that adheres the bare chip to the substrate changes from liquid to film, and a film-like adhesive material called a die-adhesive film (DAF) 18 is attached between the wafer 11 and the dicing tape 16. In the wafer 11 having the die-adhesive film 18, cutting is performed on the wafer 11 and the die-adhesive film 18. Therefore, in the peeling process, the wafer 11 and the die-adhesive film 18 are peeled off from the dicing tape 16.

[0049] The chip mounter 10 has: a wafer recognition camera 24 that recognizes the posture of the bare chip D on the wafer 11; a stage recognition camera 32 that recognizes the posture of the bare chip D mounted on the intermediate stage 31; and a substrate recognition camera 44 that recognizes the mounting position on the mounting stage BS. The posture deviation between the recognition cameras must be corrected for the stage recognition camera 32 that participates in the picking up by the mounting head 41 and the substrate recognition camera 44 that participates in the mounting to the mounting position by the mounting head 41. In this embodiment, the surface inspection of the bare chip D is performed using the lighting device described later and the wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44.

[0050] Next, use Figure 4 The control unit 8 will be described. Figure 4 Yes means Figure 1 The block diagram of the schematic structure of the control system of the chip mounter shown in FIG. 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 generally includes a control / calculation device 81 mainly composed of a CPU, a storage device 82, an input / output device 83, a bus 84, and a power supply unit 85. The storage device 82 includes a main storage device 82a composed of a RAM storing a processing program, etc., and an auxiliary storage device 82b composed of a HDD or SSD storing control data and image data required for control. The input / output device 83 includes: a monitor 83a for displaying device status and information, etc.; a touch panel 83b for inputting instructions from an operator; a mouse 83c for operating the monitor; and an image acquisition device 83d for acquiring (taking in) image data from the optical system 88. In addition, the input / output device 83 includes: a motor control device 83e, which controls the driving unit 86 such as the XY table (not shown) of the bare chip supply unit 1 and the ZY drive axis of the mounting head table; and an I / O signal control device 83f, which obtains or controls various sensor signals and signals from the signal unit 87 such as switches of the lighting device. The optical system 88 includes a wafer recognition camera 24, a stage recognition camera 32, and a substrate recognition camera 44. The control / calculation device 81 obtains the required data via the bus 84, performs calculations, and sends information to the control of the pickup head 21 and the monitor 83a.

[0051] The control unit 8 stores the image data captured by the wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44 in the storage device 82 via the image acquisition device 83d. The control / computing device 81 is used to perform positioning of the bare chip D and the packaging area P of the substrate S, and surface inspection of the bare chip D and the substrate S, through the software programmed based on the stored image data. Based on the position of the bare chip D and the packaging area P of the substrate S calculated by the control / computing device 81, the driving unit 86 is operated through the motor control device 83e through the software. Through this process, the bare chip on the wafer is positioned, and the driving unit of the pickup unit 2 and the mounting unit 4 is operated to mount the bare chip D on the packaging area P of the substrate S. The wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44 used are cameras such as grayscale cameras or color cameras, which digitize the light intensity. The wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44 are also called shooting devices.

[0052] Next, use Figure 5 A die attach process which is one process of a method for manufacturing a semiconductor device will be described. Figure 5 Yes Description Figure 1 Flow chart of the die attach process in the die attach machine shown.

[0053] (Wafer loading: process P1)

[0054] In the chip mounting process of the embodiment, first, the control unit 8 takes out the wafer ring 14 holding the wafer 11 from the wafer box and places it on the wafer holding table 12, and moves the wafer holding table 12 to the reference position for picking up the bare chip D. Then, the control unit 8 performs fine adjustment based on the image obtained by the wafer recognition camera 24 so that the configuration position of the wafer 11 accurately matches the reference position.

[0055] (Bare chip transportation: Process P2)

[0056] Next, the control unit 8 moves the wafer holding table 12 carrying the wafer 11 at a predetermined pitch and keeps it horizontal, thereby arranging the bare chip D to be picked up first to the picking position. With respect to the wafer 11, each bare chip is inspected in advance by an inspection device such as a detector, and mapping data indicating qualified or unqualified is generated for each bare chip, and the mapping data is stored in the storage device 82 of the control unit 8. Based on the mapping data, it is determined whether the bare chip D to be picked up is a qualified product or a defective product. If the bare chip D is a defective product, the control unit 8 moves the wafer holding table 12 carrying the wafer 11 at a predetermined pitch, arranges the bare chip D to be picked up next to the picking position, and skips the bare chip D that is a defective product.

[0057] (Bare chip positioning: process P3)

[0058] The control unit 8 captures the main surface (upper surface) of the bare chip D to be picked up through the wafer recognition camera 24, and calculates the positional offset of the bare chip D to be picked up relative to the above-mentioned picking position based on the acquired image. The control unit 8 moves the wafer holding table 12 on which the wafer 11 is placed based on the positional offset, and accurately arranges the bare chip D to be picked up at the picking position.

[0059] (Bare chip surface inspection: process P4)

[0060] Next, the control unit 8 performs a surface inspection of the bare chip D based on the image acquired by the wafer recognition camera 24. Here, the control unit 8 enters the next process (process P9 described later) when it is determined that there is no problem with the surface of the bare chip D, but skips the process or stops the process by error when it is determined that there is a problem. Skipping the process means skipping the process after process P9 of the bare chip D, moving the wafer holding table 12 carrying the wafer 11 at a predetermined pitch, and arranging the bare chip D to be picked up next to the pick-up position.

[0061] (Substrate loading: process P5, substrate transport: process P6)

[0062] The control unit 8 causes the substrate supply unit 6 to place the substrate S on the transport path 52. The control unit 8 causes the substrate transport claws 51 that grip and transport the substrate S to move to the mounting position.

[0063] (Substrate positioning: process P7)

[0064] The control unit 8 images the substrate S using the substrate recognition camera 44 and positions the substrate S based on the captured image.

[0065] (Substrate surface inspection: process P8)

[0066] Next, the control unit 8 performs a surface inspection of the packaging area P of the substrate S based on the image acquired by the substrate recognition camera 44. Here, the control unit 8 determines whether there is a problem in the surface inspection, and proceeds to the next process (process P9 described later) when it is determined that there is no problem with the surface of the packaging area P of the substrate S. When the control unit 8 determines that there is a problem in the surface inspection, the surface image is visually confirmed, or a higher sensitivity inspection and / or an inspection with changed lighting conditions is performed. If there is a problem, the process is skipped, and if there is no problem, the process is performed to the next process. Skipping refers to skipping the process after process P10 for the corresponding tab of the packaging area P of the substrate S, and registering the unqualified in the substrate processing information.

[0067] (Pick up: step P9, place on intermediate stage: step P10)

[0068] After the bare chip supply unit 1 accurately arranges the bare chip D to be picked up at the pickup position, the control unit 8 picks up the bare chip D from the dicing tape 16 using the pickup head 21 including the collet 22 and places it on the intermediate stage 31 .

[0069] (Bare chip position inspection: process P11)

[0070] The control unit 8 detects the posture deviation (rotation deviation) of the bare chip mounted on the intermediate stage 31 by taking pictures with the stage recognition camera 32. If there is a posture deviation, the control unit 8 rotates the intermediate stage 31 in a plane parallel to the mounting surface having the mounting position by means of a rotation drive device (not shown) provided on the intermediate stage 31 to correct the posture deviation.

[0071] (Bare chip surface inspection: process P12)

[0072] The control unit 8 performs a surface inspection of the bare chip D based on the image acquired by the stage recognition camera 32. Here, the control unit 8 enters the next process (process P13 described later) when it is determined that there is no problem with the surface of the bare chip D, but skips the process or stops the process by error when it is determined that there is a problem. Skipping the process means placing the bare chip on a defective product tray (not shown), etc., skipping the process after process P13 of the bare chip D, moving the wafer holding table 12 carrying the wafer 11 at a predetermined pitch, and arranging the bare chip D to be picked up next to the pick-up position.

[0073] (Chip mounting: process P13)

[0074] The control unit 8 picks up the bare chip D from the intermediate stage 31 using the mounting head 41 including the collet 42 , and performs die mounting on the packaging region P of the substrate S or on the bare chip mounted on the packaging region P of the substrate S.

[0075] (Inspection of relative position of bare chip and substrate: process P14)

[0076] After mounting the bare chip D, the control unit 8 checks whether the mounting position is correct by photographing the bare chip D and the substrate S through the substrate recognition camera 44. At this time, the center of the bare chip and the center of the contact are obtained to check whether the relative positions are correct.

[0077] (Surface inspection of bare chips and substrates: process P15)

[0078] Next, the control unit 8 performs surface inspection of the bare chip D and the substrate S based on the image acquired by the substrate recognition camera 44. Here, the control unit 8 proceeds to the next process (process P9 described later) when it is determined that there is no problem with the surface of the bare chip D, but skips the process or stops the process in error when it is determined that there is a problem. In the skipping process, a failure is registered in the substrate processing information.

[0079] (Substrate transport: process P16, substrate unloading: process P17)

[0080] Thereafter, the bare chips D are mounted one by one in the same procedure to the package region P of the substrate S. When mounting of one substrate is completed, the substrate S is moved to the substrate unloading section 7 by the substrate transport claws 51 and delivered to the substrate unloading section 7 .

[0081] (Wafer unloading: process P18)

[0082] After that, the bare chips D are peeled off from the dicing tape 16 one by one in the same procedure (step P9). When all bare chips D except defective ones are picked up, the dicing tape 16 and wafer ring 14 that have held the bare chips D in the shape of the wafer 11 are unloaded into the wafer cassette.

[0083] The surface inspection of cracks can be performed at least in one of the bare chip supply section 1, the intermediate stage section 3, and the mounting section 4, where the bare chip position identification is performed, but it is more preferably performed in all locations. If performed in the bare chip supply section 1, cracks can be detected as early as possible. If performed in the intermediate stage section 3, cracks that cannot be detected in the bare chip supply section 1 or cracks generated after the picking process (cracks that have not yet surfaced before the mounting process) can be detected before mounting. In addition, if performed in the mounting section 4, cracks that cannot be detected in the bare chip supply section 1 and the intermediate stage section 3 (cracks that have not yet surfaced before the mounting process) or cracks generated after the mounting process can be detected before the next bare chip is stacked or before the substrate is discharged.

[0084] Next, use Figure 6 and Figure 7 The lighting for surface inspection is explained. Figure 6 This is a diagram showing the configuration of the lighting device of the substrate recognition camera. Figure 7 Yes Description Figure 6 Schematic diagram of the movement of the lighting device.

[0085] like Figure 6As shown, the substrate recognition camera 44 is arranged perpendicular to the surface of the bare chip D. That is, the optical axis is perpendicular to the surface of the bare chip D. The lighting device 45 is an oblique light illumination, which illuminates the bare chip D at a predetermined angle (incident angle (θ)) relative to the optical axis. The incident angle (θ) of the illumination light IL is preferably less than 45 degrees, and more preferably 5 to 15 degrees. In addition, as shown in FIG. Figure 7 As shown, the lighting device 45 can rotate and move in a horizontal plane with the optical axis as the center axis. Figure 7 A scar K is shown on the surface of the bare chip D in FIG.

[0086] Here, use Figure 8 Explain scratches and cracks. Figure 8 This is a conceptual diagram illustrating scratches and cracks.

[0087] The scratch Ks is generated by some collision object CLL scratching the surface. Although it depends on the collision pressure at this time, it can be considered that the collision object CLL moves on the surface of the bare chip D in the area close to the surface of the bare chip D and collides while slightly bouncing. The crack Kc is generated, for example, by applying pressure PRS from the bottom of the bare chip D and growing in accordance with the stacking structure of the bare chip D or the crystal direction of silicon, and is easily formed in a direction close to the direction along the edge of the bare chip D.

[0088] In other words, the scratch Ks is a dotted line-shaped scratch (scratch) with a relatively shallow depth. The scratch Ks is generated near the surface layer such as a protective film layer formed by a polyimide resin or the like in the scratch K located on the surface of the bare chip D. On the other hand, the crack Kc is a continuous linear scratch and is deeper than the scratch Ks. The crack Kc penetrates the protective film layer and reaches the silicon layer. In addition, the scratch Ks is generated on the wafer surface in a specific process such as the back grinding process.

[0089] Next, use Fig. 9 (a) Fig. 9 (b) Fig.10 (a) and Fig.10 (b) explains the mechanism by which the visualization of the scratch Ks and the crack Kc differs depending on the illumination irradiation direction. Fig. 9 (a) is a diagram showing a state where illumination light is irradiated from the upper right side with respect to a scratch. Fig. 9 (b) is a diagram showing a situation where illumination light is irradiated obliquely from above the front side relative to the scratch. Fig.10 (a) is a diagram showing a case where illumination light is irradiated from a direction perpendicular to the crack direction and from the upper right side. Fig.10 (b) is a diagram showing a case where illumination light is irradiated from a direction parallel to the cracking direction of the crack and obliquely upward on the front side.

[0090] In the case of observation by dark field method in which the flaws are photographed brightly by irradiating the illumination light IL, the flaws are visualized by the reflection of light on the side (inside) of the fine flaws. Since the side of the scratch Ks is discontinuous, the side of each flaw is independent and faces all directions (multi-directional). Therefore, each flaw is visualized almost independently of the irradiation direction of the illumination light, and can be seen regardless of the direction from which the illumination light is irradiated.

[0091] On the other hand, since the crack Kc has a continuous and linear scratch, the side surface is also continuous, and the visualization of the scratch depends more on the irradiation direction of the illumination light than the scratch Ks. Therefore, in the horizontal direction, the side surface is illuminated by irradiating the illumination light from a direction different from the extension direction of the crack Kc. When the illumination light is irradiated from a direction nearly perpendicular to the extension direction of the crack Kc, the light can be efficiently reflected. On the other hand, when the light is irradiated in the horizontal direction parallel to the crack direction of the crack Kc, the side surface is not efficiently irradiated with light, and as a result, the crack Kc is not clearly visible.

[0092] Next, use Fig.11 and Fig.12 A method for distinguishing between scratches Ks and cracks Kc will be described. Fig.11 This is a diagram showing the brightness of a scratch when the irradiation direction of illumination light with respect to the scratch is changed. Fig.12 This is a diagram showing the brightness of a flaw when the irradiation direction of illumination light relative to the crack is changed.

[0093] like Figure 7 As shown, the control unit 8 rotates the illumination light IL in the horizontal direction by rotating the illumination device 45. Furthermore, the control unit 8 uses the substrate recognition camera 44 to capture the bare chip D at each specified angle or at any angle interval in the horizontal direction of the illumination device 45 and obtain a plurality of captured images. Fig.11 and Fig.12 As shown, the brightness of the scratch Ks and crack Kc in the captured image changes, but the brightness change at the crack Kc is greater than the brightness change at the scratch Ks. The threshold (Bth) is determined by the ratio relative to the maximum brightness, and the control unit 8 determines that the case below the threshold (Bth) or less than the threshold (Bth) is a crack Kc, and the case exceeding the threshold (Bth) or above the threshold (Bth) is a scratch Ks. As described above, since the crack Kc is easily formed in a direction close to the direction along the edge of the bare chip D, the irradiation direction is as follows. Figure 7As shown by the straight arrows, it is sufficient as long as there are at least two directions, a direction approximately perpendicular to one side of the bare chip D and a direction approximately perpendicular to the direction. Even if the crack Kc is formed in a direction different from the direction along the side of the bare chip D, the brightness difference of the crack caused by the irradiation from the above two directions is greater than the brightness difference of the scratch Ks, so it can be judged.

[0094] According to the present embodiment, since the difference in reflection characteristics caused by the shapes of the scratch Ks and the crack Kc is utilized, the scratch Ks and the crack Kc can be distinguished. Thus, the distinguishing ability of the inspection function in the chip mounter can be improved. In addition, based on the judgment result, the crack Kc can be regarded as a defective product and the scratch Ks can be regarded as a qualified product. Thus, the yield rate of the product assembled by the chip mounter can be improved. In addition, when it is a scratch Ks, the production operation of the device will not be stopped due to an erroneous call, etc., and production can be continued, thereby increasing the production volume.

[0095] The lighting device of the wafer recognition camera 24 and the stage recognition camera 32 in the surface inspection has the same structure as the lighting device 45. In addition, as the lighting device of the wafer recognition camera 24, the stage recognition camera 32 and the substrate recognition camera 44 in the positioning and position inspection, for example, coaxial lighting is used.

[0096] <Modification>

[0097] Several representative variations of the embodiments are illustrated below. In the following description of the variations, for parts having the same structure and function as those described in the above embodiments, the same reference numerals as those in the above embodiments can be used. Moreover, with respect to the description of the parts, the description in the above embodiments can be appropriately cited within the scope of technical non-contradiction. In addition, a part of the above embodiments and all or part of the multiple variations can be appropriately combined and applied within the scope of technical non-contradiction.

[0098] (First Modification)

[0099] use Fig.13 A lighting device according to a first modified example will be described. Fig.13 It is a diagram for explaining the lighting device in the first modified example.

[0100] The lighting device 45 may not rotate as in the embodiment. The lighting device 45 in the first modification is composed of an annular oblique light illumination, and is divided into a plurality of areas 45a to 45h and configured to be able to be independently turned on / off. The brightness of the scar can be observed by changing the lighting position of the lighting device 45 and thus changing the irradiation direction of the illumination light. Fig.13The example of dividing the annular oblique light illumination into eight regions is shown in FIG, but it is not limited to this. The illumination light irradiation direction in the horizontal direction only needs to have at least two directions, a direction substantially perpendicular to one side of the bare chip D and a direction substantially perpendicular to the direction, and the number of divisions can also be four.

[0101] (Second Modification)

[0102] use Fig.14 A lighting device according to a second modification example will be described. Fig.14 It is a diagram for explaining the lighting device in the second modified example.

[0103] The lighting device 45 may not be in the shape of a rotating track or a circle. As shown in the figure, the lighting device 45 in the second variant may also be composed of two-directional strip lighting 45j and 45k, and the strip lighting 45j and 45k are respectively lit to observe the brightness change of the scar when lit. The illumination light is irradiated in the horizontal direction in two directions: a direction roughly perpendicular to one side of the bare chip D and a direction roughly perpendicular to the direction. In the second variant, the two-directional strip lighting is used as an example, but it can also be four-directional strip lighting.

[0104] (Third Modification)

[0105] use Fig.15 A lighting device according to a third modified example will be described. Fig.15 It is a diagram for explaining the lighting device in the third modified example.

[0106] In the lighting device 45 in the third variant, regarding the incident direction of light relative to the bare chip D, the incident angle θ is kept constant and the horizontal direction is changed. In addition, the incident angle (θ) can also be appropriately changed according to the scratch Ks and the crack Kc. As described above, since the incident angle (θ) is preferably less than 45 degrees, more preferably 5 to 15 degrees, the incident angle (θ) is changed within this range. The changed incident angle (θ) is fixed and the incident direction in the horizontal direction is changed. For example, first, the incident angle (θ) is fixed to a first angle (θ1) (θ=θ1), and the lighting device 45 is rotated in a horizontal plane to change the incident direction in the horizontal direction, and the brightness change of the scar is observed. Secondly, the incident angle (θ) is fixed to a second angle (θ2) (θ=θ2), and the lighting device 45 is rotated in a horizontal plane to change the incident direction in the horizontal direction, and the brightness change of the scar is observed. Here, θ1<θ2. As a result, the brightness difference of the crack Kc can be increased compared with the embodiment.

[0107] (Fourth Modification)

[0108] The lighting device 45 in the fourth variant can also change the wavelength of light relative to the bare chip D. The wavelength of light is preferably shorter than the green wavelength having an absorption region in the surface protection film (e.g., polyimide film), and can be in the ultraviolet region. Thus, for the amount of light reaching, the crack Kc under the protection film and the scratch Ks on the upper surface can be given a greater difference through the absorption of the surface protection film (e.g., polyimide film), so that the brightness difference of the reflected light from the crack Kc and the scratch Ks is further increased.

[0109] In this case, the incident angle (θ) of the light may be larger than 45 degrees. This is to increase the path of the light reaching the protective film, to make a greater difference in the amount of light reaching the crack Kc under the protective film and the scratch Ks on the surface, and to make a greater difference in the brightness of the respective reflected lights.

[0110] In addition, the bare chip D may be photographed at each predetermined angle in the horizontal direction or at any angle intervals for the illumination device 45 and a plurality of photographed images may be acquired by using normal white visible light at an angle less than 45 degrees and using a wavelength shorter than green having an absorption region in a surface protection film (e.g., polyimide film) at an angle greater than 45 degrees among the incident angles (θ) of the two or more lights. In this way, the scratch Ks and the crack Kc can be distinguished without further reducing the detection rate of the crack Kc.

[0111] As mentioned above, the invention completed by the inventors of this application has been specifically described based on the embodiment and the modified example. However, the present invention is not limited to the above-mentioned embodiment and the modified example, and various modifications can be made.

[0112] For example, in the embodiment, the bare chip appearance inspection and recognition is performed after the bare chip position identification, but the bare chip position identification may also be performed after the bare chip appearance inspection and recognition.

[0113] In addition, in the embodiment, DAF is attached to the back surface of the wafer, but DAF does not need to be attached.

[0114] In addition, in the embodiment, there are one pick-up head and one placement head, but there may be two or more. In addition, in the embodiment, there is an intermediate stage, but there may not be an intermediate stage. In this case, the pick-up head and the placement head may also be used concurrently.

[0115] In addition, in the embodiment, the surface of the bare chip is facing upward for mounting, but after picking up the bare chip, the front and back of the bare chip can be turned over and the back of the bare chip can be facing upward for mounting. In this case, the intermediate stage can also be omitted. This device is called a flip chip bonder.

Claims

1. A chip mounting device, characterized in that: have: A photographing device having an optical axis perpendicular to a surface of the bare chip and photographing the bare chip held parallel to a horizontal direction; an illumination device for irradiating light to the bare chip at an angle inclined at a predetermined angle relative to an optical axis of the imaging device; and a control unit, which controls the photographing device and the lighting device, The control unit is configured to change the irradiation direction of the illumination light from the illumination device in the horizontal direction, photograph the plurality of bare chips through the photographing device, and identify whether the flaw formed on the bare chip in the photographed image is a crack or a scratch based on the brightness change of the flaw.

2. The chip mounting device according to claim 1, characterized in that: The control unit is configured to recognize, as a crack, a case where an image has a brightness of a flaw formed on the bare chip that is equal to or smaller than a predetermined value.

3. The chip mounting device according to claim 2, characterized in that: The control unit is configured to recognize that a flaw formed on the bare chip has an image with a brightness equal to or greater than a predetermined value as a scratch.

4. The chip mounting device according to claim 1, characterized in that: The control unit is configured to change the irradiation direction of the illumination light in the horizontal direction by rotating the illumination device in the horizontal direction.

5. The chip mounting device according to claim 1, characterized in that: The lighting device is composed of a ring lighting device, which is formed by a plurality of areas that can be lit and extinguished independently, The control unit is configured to change the irradiation direction of the illumination light in the horizontal direction by lighting a specific area among the plurality of areas.

6. The chip mounting device according to claim 1, characterized in that: The lighting device is composed of a plurality of long lighting devices that can be independently lit and extinguished. The control unit is configured to change the irradiation direction of the illumination light in the horizontal direction by lighting a specific strip lighting device among the plurality of strip lighting devices.

7. The chip mounting device according to claim 4, characterized in that: The control unit is configured to change the irradiation direction of the illumination light in the vertical direction and the horizontal direction by changing the incident angle of the illumination device and rotating the illumination device in the horizontal direction.

8. The chip mounting device according to claim 1, characterized in that: The invention further comprises a bare chip supply unit having a wafer ring holder for holding a dicing tape to which the bare chip is attached. The control unit uses the imaging device and the lighting device to image the bare chip attached to the dicing tape.

9. The chip mounting device according to claim 1, characterized in that: A mounting head is also provided, and the mounting head mounts the bare chip onto a substrate or an already mounted bare chip. The control unit uses the imaging device and the lighting device to image the bare chip mounted on the substrate or the bare chip.

10. The chip mounting device according to claim 1, characterized in that: Also available: a pick-up head that picks up the bare chip; and The intermediate stage carries the picked-up bare chip. The control unit uses the imaging device and the lighting device to image the bare chip placed on the intermediate stage.

11. A method for manufacturing a semiconductor device, characterized in that: include: A substrate carrying step of carrying a substrate into a chip mounting device, the chip mounting device comprising a camera having an optical axis perpendicular to a surface of a bare chip and photographing the bare chip held in parallel with a horizontal direction, a lighting device irradiating light to the bare chip at an angle inclined at a predetermined angle with respect to the optical axis of the camera, and a control unit controlling the camera and the lighting device, the control unit being configured to: change the irradiation direction of the illumination light from the lighting device in the horizontal direction and photograph a plurality of the bare chips by the camera, and identify whether the flaw formed on the bare chip in the photographed image is a crack or a scratch based on a change in brightness of the flaw; The wafer loading process is to load the wafer ring holder that holds the dicing tape with the bare chip attached thereto; A picking process of picking up the bare chip; and The mounting process mounts the picked-up bare chip onto the substrate or onto the bare chip already mounted on the substrate.

12. The method for manufacturing a semiconductor device according to claim 11, wherein: In the picking process, the picked-up bare chip is placed on an intermediate stage, In the mounting step, the bare chip placed on the intermediate stage is picked up.

13. The method for manufacturing a semiconductor device according to claim 11, wherein: Before the picking up step, the method further includes a step of inspecting the surface of the bare chip using the imaging device and the lighting device.

14. The method for manufacturing a semiconductor device according to claim 11, wherein: After the mounting step, the method further includes a step of inspecting the surface of the bare chip using the imaging device and the lighting device.

15. The method for manufacturing a semiconductor device according to claim 12, wherein: After the picking up step and before the mounting step, the method further includes a step of inspecting the surface of the bare chip using the imaging device and the lighting device.

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