JP2018195735A - Semiconductor manufacturing apparatus and manufacturing method of semiconductor device - Google Patents

Abstract

When an abnormality on the surface of a semiconductor chip (die) is detected by binarization or an image difference method with a non-defective product, a crack having a width of less than one pixel cannot be found. A semiconductor manufacturing apparatus includes: an imaging device configured to image a die; an illumination device arranged on a line connecting the die and the imaging device; and a control device configured to control the imaging device and the illumination device. Prepare. The control device illuminates a part of the die with the lighting device, forms a bright portion, a dark portion, and a gradation portion between the bright portion and the dark portion on the die, and images the die with the imaging device. I do. [Selection diagram] FIG.

Description

  The present disclosure relates to a semiconductor manufacturing apparatus, and can be applied to, for example, a die bonder including a camera that recognizes a die.

  When a semiconductor chip is manufactured by dicing a disk-shaped wafer in advance, cracks extending from the cut surface to the inside may occur due to cutting resistance during dicing. The separated semiconductor chip is inspected for the presence or absence of cracks, and the quality of the product is determined (for example, Japanese Patent Application Laid-Open No. 2008-98348).

JP 2008-98348 A JP 2008-66452 A

If abnormality detection on the surface of a semiconductor chip (die) is performed by a method of binarizing a captured image or an image difference method with a non-defective product, a crack with a width of less than one pixel cannot be found.
The subject of this indication is providing the technique which can improve the recognition accuracy of a crack.
Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

An outline of typical ones of the present disclosure will be briefly described as follows.
That is, the semiconductor manufacturing apparatus includes an imaging device that images a die, an illumination device that is disposed on a line connecting the die and the imaging device, and a control device that controls the imaging device and the illumination device. The control device illuminates a part of the die with the illumination device, forms a bright part, a dark part, and a gradation part between the bright part and the dark part on the die, and images the die with the imaging device To do.

  According to the semiconductor manufacturing apparatus, the crack recognition accuracy can be improved.

Schematic top view showing a configuration example of a die bonder The figure explaining schematic structure when it sees from the arrow A direction in FIG. FIG. 1 is an external perspective view showing the configuration of the die supply unit of FIG. Schematic sectional view showing the main part of the die supply unit of FIG. The block diagram which shows schematic structure of the control system of the die bonder of FIG. Flowchart explaining the die bonding process in the die bonder of FIG. Flowchart for explaining copying operation Diagram showing an example of a unique part (selected area) Diagram showing examples of registered images and similar images Flow chart for explaining the continuous construction operation Diagram showing an image of a die with cracks The figure which shows the image which binarized the image of FIG. Diagram showing a good die image The figure which shows the difference of the image of FIG. 11 and the image of FIG. Diagram showing an image when the crack is thick Diagram showing an image when the crack is thin The figure which shows the image for demonstrating the indirect detection system of a crack The figure for demonstrating the optical system of a wafer supply part The figure for explaining the light source of the coaxial illumination Diagram for explaining crack indirect detection method The figure which shows the image for demonstrating the indirect detection system of a crack The figure which shows the image for demonstrating the indirect detection system of a crack The figure for demonstrating the light emission surface and shielding surface of illumination The figure for demonstrating an illumination part Diagram for explaining surface-emitting illumination Captured image of crack

  As part of the manufacturing process of a semiconductor device, there is a process of assembling a package by mounting a semiconductor chip (hereinafter simply referred to as a die) on a wiring board, a lead frame or the like (hereinafter simply referred to as a substrate). In part, there are a step of dividing a die from a semiconductor wafer (hereinafter simply referred to as a wafer) and a bonding step of mounting the divided die on a substrate. A semiconductor manufacturing apparatus used in the bonding process is a die bonder.

  The die bonder is an apparatus for bonding (mounting and bonding) a die onto a substrate or an already bonded die using solder, gold plating, or resin as a bonding material. For example, in a die bonder that bonds a die to the surface of a substrate, the die is adsorbed from the wafer using a suction nozzle called a collet, picked up, transported onto the substrate, imparts pressing force, and heats the bonding material. By doing so, the operation (work) of performing bonding is repeated. The collet is a holder that has suction holes, sucks air, and sucks and holds the die, and has the same size as the die.

<Embodiment>
The semiconductor manufacturing apparatus according to the embodiment will be described below. In addition, the code | symbol in parenthesis is an illustration, Comprising: It is not limited to this.
The semiconductor manufacturing apparatus (10) includes an imaging device (ID) that images the die (D), an illumination device (LD) that is disposed on a line connecting the die (D) and the imaging device (ID), and an imaging device ( ID) and a control device (8) for controlling the illumination device (LD). The control device (8) illuminates a part of the die (D) with the illumination device (LD), and gradation between the bright part (B), the dark part (S), and the bright part (B) and the dark part (S). The part (M) is formed on the die (D), and the die (D) is imaged by the imaging device (ID).
As a result, it is possible to find cracks with a width of less than one pixel that cannot be detected by binarization or the image difference method with a non-defective product on the die surface, and the crack recognition accuracy can be improved. is there.

  Examples will be described below with reference to the drawings. However, in the following description, the same components may be denoted by the same reference numerals and repeated description may be omitted. In order to clarify the description, the drawings may be schematically represented with respect to the width, thickness, shape, etc. of each part as compared to the actual embodiment, but are merely examples, and the interpretation of the present invention is not limited to them. It is not limited.

  FIG. 1 is a top view schematically illustrating a die bonder according to an embodiment. FIG. 2 is a diagram for explaining the operation of the pickup head and the bonding head when viewed from the direction of arrow A in FIG.

  The die bonder 10 is roughly divided into a supply unit 1 for supplying a die D to be mounted on a substrate 9 on which a product area (hereinafter referred to as a package area P) to be one or a plurality of final packages is printed, a pickup unit 2, The intermediate stage unit 3, the bonding unit 4, the transport unit 5, the substrate supply unit 6, the substrate carry-out unit 7, and a control unit 8 that monitors and controls the operation 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.

  First, the die supply unit 1 supplies a die D to be mounted on the package area P of the substrate 9. The die supply unit 1 includes a wafer holding table 12 that holds the wafer 11 and a push-up unit 13 indicated by a dotted line that pushes up the die D from the wafer 11. The die supply unit 1 is moved in the XY directions by a driving means (not shown), and the die D to be picked up is moved to the position of the push-up unit 13.

  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 direction, and drive units (not shown) that move the collet 22 up and down, rotate, and move in the X direction. Have. The pickup head 21 has a collet 22 (see also FIG. 2) that holds the pushed-up die D at the 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 driving units (not shown) that move the collet 22 up and down, rotate, and move in the X direction.

  The intermediate stage unit 3 includes an intermediate stage 31 on which the die D is temporarily placed and a stage recognition camera 32 for recognizing the die D on the intermediate stage 31.

The bonding unit 4 picks up the die D from the intermediate stage 31 and bonds the die D on the package area P of the substrate 9 being conveyed, or stacks the die D on the die already bonded on the package area P of the substrate 9. Bond in shape. The bonding unit 4 includes a bonding head 41 having a collet 42 (see also FIG. 2) for attracting and holding the die D at the tip like the pickup head 21, a Y driving unit 43 for moving the bonding head 41 in the Y direction, and a substrate. 9 has a substrate recognition camera 44 that picks up an image of a position recognition mark (not shown) of the package area P and recognizes the bonding position.
With such a configuration, the bonding head 41 corrects the pickup position / orientation based on the imaging data of the stage recognition camera 32, picks up the die D from the intermediate stage 31, and the substrate based on the imaging data of the substrate recognition camera 44. The die D is bonded to the substrate.

The transport unit 5 includes a substrate transport claw 51 that grips and transports the substrate 9 and a transport lane 52 in which the substrate 9 moves. The substrate 9 is moved by driving a nut (not shown) of the substrate transfer claw 51 provided on the transfer lane 52 with a ball screw (not shown) provided along the transfer lane 52.
With such a configuration, the substrate 9 moves from the substrate supply unit 6 to the bonding position along the transfer lane 52, moves to the substrate unloading unit 7 after bonding, and passes the substrate 9 to the substrate unloading unit 7.

  The control unit 8 includes a memory that stores a program (software) that monitors and controls the operation of each unit of the die bonder 10, and a central processing unit (CPU) that executes the program stored in the memory.

  Next, the configuration of the die supply unit 1 will be described with reference to FIGS. 3 and 4. FIG. 3 is an external perspective view of the die supply unit. FIG. 4 is a schematic cross-sectional view showing the main part of the die supply unit.

  The die supply unit 1 includes a wafer holding table 12 that moves in the horizontal direction (XY direction) and a push-up unit 13 that moves in the vertical direction. The wafer holder 12 includes an expand ring 15 that holds the wafer ring 14 and a support ring 17 that horizontally positions the dicing tape 16 that is held by the wafer ring 14 and to which a plurality of dies D are bonded. The push-up unit 13 is disposed inside the support ring 17.

  The die supply unit 1 lowers the expand ring 15 holding the wafer ring 14 when the die D is pushed up. As a result, the dicing tape 16 held on the wafer ring 14 is stretched to widen the distance between the dies D, and the die D is pushed up from below the die D by the push-up unit 13 to improve the pick-up property of the die D. Note that the adhesive that bonds the die to the substrate in accordance with the reduction in thickness is changed from a liquid to a film, and a film-like adhesive material called a die attach film (DAF) 18 is attached between the wafer 11 and the dicing tape 16. Yes. In the wafer 11 having the die attach film 18, dicing is performed on the wafer 11 and the die attach film 18. Therefore, in the peeling process, the wafer 11 and the die attach film 18 are peeled from the dicing tape 16. In the following description, the presence of the die attach film 18 is ignored.

  The die bonder 10 includes a wafer recognition camera 24 that recognizes the posture of the die D on the wafer 11, a stage recognition camera 32 that recognizes the posture of the die D placed on the intermediate stage 31, and a mounting position on the bonding stage BS. And a substrate recognition camera 44 for recognition. It is the stage recognition camera 32 that is involved in the pickup by the bonding head 41 and the substrate recognition camera 44 that is involved in the bonding to the mounting position by the bonding head 41 that must correct the posture deviation between the recognition cameras. In this embodiment, the wafer recognition camera 24 is used to detect cracks in the die D.

  The control unit 8 will be described with reference to FIG. FIG. 5 is a block diagram showing a schematic configuration of the control system. 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 broadly includes a control / arithmetic apparatus 81 mainly composed of a CPU (Central Processor 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 configured by a RAM that stores processing programs and the like, and an auxiliary storage device 82b configured by an HDD that stores control data and image data necessary for control. And have. The input / output device 83 includes a monitor 83a for displaying device status and information, a touch panel 83b for inputting operator instructions, a mouse 83c for operating the monitor, and an image capturing device 83d for capturing image data from the optical system 88. And having. The input / output device 83 includes a motor control device 83e that controls a drive unit 86 such as an XY table (not shown) of the die supply unit 1 and a ZY drive shaft of the bonding head table, and various sensor signals and illumination devices. And an I / O signal control device 83f that takes in or controls a signal from a signal unit 87 such as a switch. The optical system 88 includes a wafer recognition camera 24, a stage recognition camera 32, and a substrate recognition camera 44. The control / arithmetic unit 81 takes in necessary data via the bus line 84, calculates the data, and sends information to the control of the pickup head 21 and the like, the monitor 83a and the like.

  The control unit 8 stores 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 capturing device 83d. With the software programmed based on the stored image data, positioning of the package area P of the die D and the substrate 9 and surface inspection of the die D and the substrate 9 are performed using the control / arithmetic unit 81. Based on the position of the die D and the package area P of the substrate 9 calculated by the control / arithmetic unit 81, the drive unit 86 is moved by the software via the motor control unit 83e. The die is positioned on the wafer by this process, and the die D is bonded onto the package area P of the substrate 9 by operating the pickup unit 2 and the driving unit of the bonding unit 4. The wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44 to be used are gray scale, color, etc., and digitize the light intensity.

FIG. 6 is a flowchart for explaining a die bonding process in the die bonder of FIG.
In the die bonding process of the embodiment, first, the control unit 8 takes out the wafer ring 14 holding the wafer 11 from the wafer cassette and places it on the wafer holding table 12, and the wafer holding table 12 is picked up by the die D. The wafer is transported to a reference position to be performed (wafer loading (process P1)). Next, the control unit 8 performs fine adjustment from the image acquired by the wafer recognition camera 24 so that the arrangement position of the wafer 11 exactly matches the reference position.

  Next, the control unit 8 moves the wafer holding table 12 on which the wafer 11 is placed at a predetermined pitch and holds it horizontally to place the die D to be picked up first at the pickup position (die transfer). (Process P2)). The wafer 11 is inspected in advance for each die by an inspection device such as a prober, and map data indicating good or defective is generated for each die and stored in the storage device 82 of the control unit 8. Whether the die D to be picked up is a non-defective product or a defective product is determined based on the map data. When the die D is defective, the control unit 8 moves the wafer holding table 12 on which the wafer 11 is placed at a predetermined pitch, and arranges the die D to be picked up next at the pickup position. Die D is skipped.

  The control unit 8 images the main surface (upper surface) of the die D to be picked up by the wafer recognition camera 24, and calculates the amount of positional deviation from the pickup position of the die D to be picked up from the acquired image. The control unit 8 moves the wafer holding table 12 on which the wafer 11 is placed based on the positional deviation amount, and accurately places the die D to be picked up at the pick-up position (die positioning (process P3)).

  Next, the controller 8 performs a surface inspection of the die D from the image acquired by the wafer recognition camera 24 (process P4). Details of the die surface inspection (appearance inspection) will be described later. Here, the control unit 8 determines whether or not there is a problem in the surface inspection. When it is determined that there is no problem on the surface of the die D, the control unit 8 proceeds to the next process (process P9 described later), but determines that there is a problem. In such a case, the surface image is visually checked, and if there is a problem, skip processing is performed, and if there is no problem, processing in the next step is performed. In the skip processing, the process after P9 of the die D is skipped, the wafer holding table 12 on which the wafer 11 is placed is moved by a predetermined pitch, and the die D to be picked up next is arranged at the pickup position.

  The control unit 8 places the substrate 9 on the transport lane 52 by the substrate supply unit 6 (substrate loading (process P5)). The control unit 8 moves the substrate transport claw 51 that grips and transports the substrate 9 to the bonding position (substrate transport (process P6)).

  The substrate is imaged and positioned by the substrate recognition camera 44 (substrate positioning (process P7)).

  Next, the control unit 8 performs surface inspection of the package area P of the substrate 9 from the image acquired by the substrate recognition camera 44 (process P8). Details of the substrate surface inspection will be described later. Here, the control unit 8 determines whether or not there is a problem in the surface inspection, and if it is determined that there is no problem on the surface of the package area P of the substrate 9, the process proceeds to the next step (step P9 described later). If it is determined that there is a problem, the surface image is visually confirmed. If there is a problem, a skip process is performed. If there is no problem, the next process is performed. In the skip processing, the process P10 and subsequent steps to the corresponding tab in the package area P of the substrate 9 are skipped, and defect registration is performed in the substrate start information.

  The control unit 8 accurately arranges the die D to be picked up at the pick-up position, and then picks up the die D from the dicing tape 16 by the pick-up head 21 including the collet 22 (die handling (process P9)). (Step P10) The control unit 8 detects the posture deviation (rotational deviation) of the die placed on the intermediate stage 31 by imaging with the stage recognition camera 32 (step P11). If there is a posture deviation, the middle stage 31 is swung on a plane parallel to the mounting surface having the mounting position by a turning drive device (not shown) provided on the intermediate stage 31 to correct the posture deviation.

  The control unit 8 performs surface inspection of the die D from the image acquired by the stage recognition camera 32 (process P12). Details of the die surface inspection (appearance inspection) will be described later. Here, the control unit 8 determines whether or not there is a problem in the surface inspection. When it is determined that there is no problem on the surface of the die D, the control unit 8 proceeds to the next process (process P13 described later), but determines that there is a problem. In such a case, the surface image is visually checked, and if there is a problem, skip processing is performed, and if there is no problem, processing in the next step is performed. In the skip process, the process after the process P13 of the die D is skipped, the wafer holding table 12 on which the wafer 11 is placed is moved by a predetermined pitch, and the die D to be picked up next is arranged at the pickup position.

  The control unit 8 picks up the die D from the intermediate stage 31 by the bonding head 41 including the collet 42, and performs die bonding to the package area P of the substrate 9 or the die already bonded to the package area P of the substrate 9 (die attach). ((Step P13)).

  After bonding the die D, the control unit 8 inspects whether or not the bonding position is accurately performed (inspection of the relative position between the die and the substrate (process P14)). At this time, the center of the die and the center of the tab are obtained in the same manner as the die alignment described later, and it is inspected whether the relative position is correct.

  Next, the control unit 8 performs surface inspection of the die D and the substrate 9 from the image acquired by the substrate recognition camera 44 (process P15). Details of the surface inspection of the die D and the substrate 9 will be described later. Here, the control unit 8 determines whether or not there is a problem in the surface inspection, and when it is determined that there is no problem on the surface of the bonded die D, the process proceeds to the next step (step P9 described later), but there is a problem. If it is determined, the surface image is visually confirmed. If there is a problem, the skip process is performed. If there is no problem, the next process is performed. In the skip processing, defect registration is performed in the substrate start information.

  Thereafter, the die D is bonded to the package area P of the substrate 9 one by one according to the same procedure. When bonding of one substrate is completed, the substrate transfer claw 51 moves the substrate 9 to the substrate unloading unit 7 (substrate transfer (process P16)), and passes the substrate 9 to the substrate unloading unit 7 (substrate unloading (process P17). )).

  Thereafter, the dies D are peeled off from the dicing tape 16 one by one according to the same procedure (step P9). When the pick-up of all the dies D excluding defective products is completed, the dicing tape 16 and the wafer ring 14 holding the dies D with the outer shape of the wafer 11 are unloaded to the wafer cassette (process P18).

  A die positioning method will be described with reference to FIGS. FIG. 7 is a flowchart for explaining the copying operation. FIG. 8 is a diagram showing an example of a unique portion (selected region). FIG. 9 is a diagram showing examples of registered images and similar images. FIG. 10 is a flowchart for explaining the continuous construction operation.

  The die positioning algorithm mainly uses template matching, and uses a generally known normalized correlation equation. The result is taken as the coincidence rate. Template matching includes a reference learning copying operation and a continuous construction operation.

  First, the copying operation will be described. The controller 8 transports the reference sample to the pickup position (Step S1). The control unit 8 acquires the reference sample image PCr with the wafer recognition camera VSW (step S2). The operator of the die bonder selects a unique portion UA as shown in FIG. 8 from the image by using a human interface (touch panel 83b or mouse 83c) (step S3). The control unit 8 stores the positional relationship (coordinates) between the selected unique portion (selected region) UA and the reference sample in the storage device 82 (step S4). The controller 8 stores the image (template image) PT of the selected area in the storage device 82 (step S5). The reference work image and its coordinates are stored in the storage device.

Next, the continuous operation will be described. The control unit 8 conveys the member (product wafer) to the pickup position for continuous construction (step S11). The controller 8 acquires the product die image PCn with the wafer recognition camera VSW (step S2). As shown in FIG. 9, the control unit 8 compares the template image PT stored in the copying operation with the acquired image PCn of the product die, and calculates the coordinates of the image PTn of the most similar part (step S13). . The coordinates and the coordinates measured with the reference sample are compared, and the position of the product die (the offset between the image PTn and the template image PT) is calculated (step S14).
Die appearance inspection recognition (detection of abnormalities such as cracks and foreign matter) will be described with reference to FIGS. FIG. 11 shows an image of a die with cracks. FIG. 12 is a view showing an image obtained by binarizing the image of FIG. FIG. 13 shows an image of a good die. FIG. 14 is a diagram showing the difference between the image of FIG. 11 and the image of FIG.

  Anomaly detection on the die surface uses a technique such as binarization or an image difference method. An image PC2 (FIG. 12) obtained by binarizing the die image PCa (FIG. 11) having the crack CR is generated, and an abnormal portion (crack CR) is detected. An image PCa-n is generated by taking the difference between the die image PCa with the crack CR (FIG. 11) and the good die image PCn (FIG. 13), and the crack CR is detected.

The subject of said method is demonstrated using FIG. FIG. 15 is an image when the crack is thick. FIG. 16 is an image when the crack is thin. In the above method, the crack is directly seen, and it can be detected when the crack CR1 of the image PCa1 is thick as shown in FIG. 15, but the crack CR2 of the image PCa2 becomes thin or light in color as shown in FIG. Once detected, it is difficult to detect. That is, the above method has the following problems.
(1) A crack with a width of less than one pixel cannot be found. If the crack width is less than one pixel and an attempt is made to copy the crack with an image, the image becomes faint and cannot be recognized. In consideration of the direction of the crack, etc., it cannot be reliably detected unless there is substantially a width of 3 pixels or more.
(2) Easily affected by the surface pattern of the die When there is a complex pattern on the die surface, it is difficult to distinguish it from cracks running on the surface.
(3) It is difficult to control the brightness of cracks. It is difficult to project only cracks brightly or darkly.

  Since the above problem is a problem caused by direct observation of cracks as in die positioning recognition, and product defects can be determined by the presence or absence of cracks, and the width does not need to be considered. A detection method was devised.

  FIG. 17 is an image for explaining an indirect crack detection method. The indirect detection method for cracks is a method for detecting changes occurring in the surroundings when there is a crack. For example, as shown in FIG. 17, if the brightness of the die image PC changes with the crack CR as a boundary, the crack can be caught regardless of the width of the crack CR. In FIG. 17, the image on the right side of the crack CR is dark and the image on the left side is bright. Hereinafter, specific means of the crack indirect detection method will be described.

First, the substrate recognition camera will be described with reference to FIG. FIG. 18 is a diagram for explaining the optical system of the bonding unit, and shows the arrangement of the substrate recognition camera and the illumination unit that irradiates the die with light for image capturing.
The imaging unit ID of the substrate recognition camera 44 is connected to one end of the lens barrel BT, and an objective lens (not shown) is attached to the other end of the lens barrel BT, and an image of the main surface of the die D is taken through this objective lens. It is the composition to do.
Between the lens barrel BT and the die D on the line connecting the imaging unit ID and the die D, an illumination unit LD including a surface emitting illumination (light source) SL and a half mirror (semi-transmissive mirror) HM is disposed. ing. The irradiation light from the surface emitting illumination SL is reflected by the half mirror HM on the same optical axis as that of the imaging unit ID and is applied to the die D. The scattered light irradiated to the die D with the same optical axis as the image pickup unit ID is reflected by the die D, and the regular reflection light of the light passes through the half mirror HM and reaches the image pickup unit ID to form an image of the die D. To do. That is, the illumination unit LD has a function of coaxial epi-illumination (coaxial illumination).

  Although the substrate recognition camera 44 and its illumination unit LD have been described, the stage recognition camera 32 and its illumination unit, the wafer recognition camera 24 and its illumination unit are the same.

  The mechanism of coaxial illumination will be described with reference to FIG. FIG. 19 is a diagram for explaining a light source for coaxial illumination.

  In the coaxial illumination, if the light source is arranged as it is, the optical path between the die and the camera is blocked. Therefore, as shown in FIG. 19, the half mirror HM is placed and the light source SL is arranged at a position off the optical path. However, from the viewpoint of the die D, it can be considered that the light source (virtual light source) VSL exists at the virtual position between the die and the camera by the half mirror HM. However, the light intensity of the virtual light source VSL is lower than that of the actual light source SL. Hereinafter, the position of the light source of the coaxial illumination is indicated by a virtual light source VSL of light.

  In this embodiment, a smaller angle difference that occurs naturally in the through crack is used. Since the angle difference is small, it becomes difficult to detect, and therefore, an illumination method and a method for detecting the same are used to raise a slight level difference in the crack portion penetrating the die.

  FIG. 20 is a diagram for explaining a crack indirect detection method. FIG. 21 is a diagram showing an image for explaining the crack indirect detection method. FIG. 21A shows a case where there are few shadow areas, FIG. 21B shows a case where the shadow area is medium, FIG. 21C shows a case where there are many shadow areas. FIG. 22 is a diagram showing an image for explaining the crack indirect detection method, FIG. 22A is an image with a crack when the edge extraction filter is not used, and FIG. 22B is when the edge extraction filter is not used. 22C shows an image with a crack when using the edge extraction filter, and FIG. 22D shows an image without a crack when using the edge extraction filter.

  As shown in FIG. 20, a part of the light emitting surface of the virtual light source VSL is shielded by a shielding plate SHL, for example. As shown in FIGS. 20 and 21, a shadow area S is generated by the shielding area, and an intermediate area M with gradation is generated at the boundary between the shadow and the non-shadow area B. When a crack occurs in the intermediate region M, a light-dark difference tends to appear clearly at the boundary surface of the crack CR as shown in FIG. The crack CR is imaged by a slight step.

  By using an edge extraction filter such as a Sobel filter, a Laplacian filter, a Roberts filter, or a pre-witt filter, the image obtained by this method (FIG. 22A) can be converted into an existing pattern as shown in FIG. The crack portion can be separated from the gradation region.

  The separated image (FIG. 22C) is subjected to a difference process with an image (FIG. 22D) subjected to the same processing with a crack-free (non-defective) die, so that the crack portion and the existing pattern are represented. Can be separated. This can be detected by checking the density of the differentially processed image (difference image) since the image of the die having a crack and the non-defective die are not the same. Thereby, the position and length of a crack part are detectable. In addition to difference images, edge detection (including the use of spatial filters such as Sobel filters and differential filters) that detects whether there are unintended edges in the image, and luminance data that detects changes in the average luminance and histogram of the specified area May be used.

  FIG. 23 is a diagram for explaining a light emitting surface and a shielding surface of illumination. FIG. 23A is a diagram illustrating a preferred example, and FIG. 23B is a diagram illustrating an unfavorable example.

  In FIG. 23A, the boundary surface A1 between the light emitting surface EA and the shielding surface SA is clear, and the light emitting surface EA and the shielding surface SA are not uneven. In FIG. 23B, there is an intermediate region B1 between the light emitting surface EA and the shielding surface SA, the boundary surface is not clear, and the light emitting surface EA and the shielding surface SA are uneven. It is preferable that the boundary surface is not light and the light emitting surface and the shielding surface are not uneven.

  The crack indirect detection method of the embodiment uses the discontinuity of the crack as a plane of the boundary surface and the boundary surface of the illumination irradiation area, gives contrast to the brightness on both sides of the boundary surface, and detects a minute width crack. Make it easier to do. Normally (for example, direct detection type die positioning recognition), a coaxial illumination having a sufficient light emitting surface area is prepared for viewing the entire view of the die. The light emitting surface area of the virtual light source VSL is made sufficiently larger than the area of the die D.

On the other hand, in the indirect detection method, means for reducing the light emitting surface area (or irradiation area) is provided to form the light emitting surface and the shielding surface. However, in order to be able to switch between both the direct detection method and the indirect detection method, means for increasing or decreasing the light emitting surface area (means for controlling the light emitting surface) is provided. The means for controlling the light emitting surface is:
(A) Movement of shielding plate (shielding plate SHL in FIG. 20) (b) ON / OFF of liquid crystal
(C) Switching of light emitting area and light shielding area by partial ON / OFF of planarly arranged LEDs (d) Movement of illumination for illuminating die (e) Movement of camera for imaging crack (f) Irradiation of discontinuity The die is moved with respect to the boundary surface of the area using, for example, an intermediate stage.
This is realized by such a method. Hereinafter, the control of the light emitting surface will be described by taking the partial ON / OFF of the planarly arranged LEDs in (c) as an example. FIG. 24 is a perspective view of the illumination unit. FIG. 25 is a cross-sectional view of surface emitting illumination. FIG. 26 is a diagram illustrating a captured image of a crack.

  The surface-emitting illumination SL in the illumination unit LD is a surface-emitting LED light source, and includes an LED substrate SL1 having planarly arranged LEDs, a diffusion plate SL2 provided to face the LED substrate SL1, an LED substrate SL1, and a diffusion plate. And a shielding plate SL3 provided between SL2. A region where the LED is turned on (ON) and a region where the LED is turned off (OFF) are provided with the shielding plate SL3 as a boundary. For example, the LED substrate SL1 is divided into an upper first region SL1A and a lower second region SL1B. In the direct detection method, the LEDs in both the first region SL1A and the second region SL1B are turned on to increase the light emitting surface area. In the indirect detection method, for example, the LED in the first region SL1A is turned on and the LED in the second region SL1B is turned off to reduce the light emitting surface area and form the light emitting surface and the shielding surface. This can be the same as in FIG.

  As described above, when a shielding plate is inserted inside the surface light emitting type LED light source and light emission is controlled for each boundary, cracks can be visualized in the crack detectable area CDA as shown in FIG. Cracks near the boundary of the reflecting surface of the illumination that has appeared can be visualized. At this time, it is preferable that the light emitting surface boundary of the surface of the diffusion plate that diffuses light is firmly formed.

  By switching between the light emitting surface and the shielding surface, the detectable area can be expanded. Further, the detectable area can be expanded by moving the shielding plate SL3 or by providing a plurality of shielding plates SL3 and changing the area between the light emitting surface and the shielding surface.

  A liquid crystal panel may be used instead of the diffusion plate SL2. In this case, the shielding plate SL3 is unnecessary, and the inspectable area can be expanded by controlling the transmission / non-transmission area of the liquid crystal panel.

  The appearance inspection of the crack is performed at at least one of the die supply unit, the intermediate stage, and the bonding stage, which is a place where the die position is recognized. It is more preferable to carry out at a location. By going to the intermediate stage, cracks that could not be detected by the die supply unit or cracks that occurred after the pick-up process (cracks that did not appear before the bonding process) can be detected before bonding. In addition, if it goes to the bonding stage, a crack that could not be detected by the die supply unit and the intermediate stage (a crack that did not appear before the bonding process) or a crack that occurred after the bonding process is laminated to the next die. It can be detected before or before substrate discharge.

  Although the invention made by the present inventor has been specifically described based on the embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made. Not too long.

For example, in the embodiment, the coaxial illumination has been described as being disposed between the objective lens and the die, but it may be an in-lens insertion type.
In the embodiment, the die appearance inspection recognition is performed after the die position recognition. However, the die position recognition may be performed after the die appearance inspection recognition.
In the embodiment, DAF is affixed to the back surface of the wafer, but DAF is not necessary.
In the embodiment, one pickup head and one bonding head are provided, but two or more may be provided. Moreover, although the intermediate stage is provided in the embodiment, the intermediate stage may not be provided. In this case, the pickup head and the bonding head may be combined.
Further, in the embodiment, the bonding is performed with the die surface facing up, but after picking up the die, the front and back surfaces of the die may be reversed and the bonding may be performed with the back surface of the die facing up. In this case, the intermediate stage may not be provided. This device is called a flip chip bonder.
In the embodiment, the bonding head is provided, but the bonding head may not be provided. In this case, the picked up die is placed on a container or the like. This device is called a pickup device.

  Further, the light emitting area shading area may be readjusted and reinspected in accordance with the direction of the previously detected crack. Thereby, a detection rate can be improved.

DESCRIPTION OF SYMBOLS 10 ... Die bonder 1 ... Die supply part 13 ... Push-up unit 2 ... Pick-up part 24 ... Wafer recognition camera 3 ... Alignment part 31 ... Intermediate stage 32 ... Stage recognition Camera 4 ... Bonding unit 41 ... Bonding head 42 ... Collet 44 ... Substrate recognition camera 5 ... Transport unit 51 ... Substrate transport claw 8 ... Control unit 9 ... Substrate BS ... Bonding stage D ... Die P ... Package area LD ... Illumination part HM ... Half mirror SL ... Light source SL1 ... LED substrate SL1A ... First area SL1B ... Second region SL2 ... diffusion plate SL3 ... shielding plate

Claims (19)

An imaging device for imaging the die;
A lighting device disposed on a line connecting the die and the imaging device;
A control device for controlling the imaging device and the illumination device;
With
The control device illuminates a part of the die with the illumination device, forms a bright part, a dark part, and a gradation part between the bright part and the dark part on the die, and images the die with the imaging device Semiconductor manufacturing equipment. In claim 1,
The control device performs a difference process between an image obtained by processing an image of the die using an edge extraction filter and an image obtained by performing a process using the edge extraction filter on a die having no crack. apparatus. In claim 1,
The lighting device has a light emitting surface and a shielding surface. In claim 3,
The said illuminating device is coaxial illumination provided with the half mirror arrange | positioned on the centerline of the said imaging device, and the light emission source arrange | positioned beside the said half mirror. Semiconductor manufacturing apparatus. In claim 4,
The light emitting source is a surface light emitting source, has a first region and a second region, and can be individually controlled to turn on and off the first region and the second region. In claim 5,
The first region is the light emitting surface, and the second region is the shielding surface. In claim 6,
The light emitting source includes an LED substrate having LEDs arranged in a plane, a diffusion plate provided to face the LED substrate, and a shielding plate provided between the LED substrate and the diffusion plate. ,
The said shielding board is arrange | positioned in the boundary of the said 1st area | region and the said 2nd area | region. Semiconductor manufacturing apparatus. In claim 6,
The light emitting source includes an LED substrate having LEDs arranged in a plane, and a liquid crystal panel provided to face the LED substrate,
The liquid crystal panel forms the first region and the second region. A semiconductor manufacturing apparatus. In claim 1,
The control device moves the imaging device, illuminates a part of the die, forms a bright portion, a dark portion, and a gradation portion between the bright portion and the dark portion on the die, and the imaging device Semiconductor manufacturing equipment that captures images of dies. In claim 1,
The control device moves the die, illuminates a part of the die, forms a bright part, a dark part, and a gradation part between the bright part and the dark part on the die. Semiconductor manufacturing equipment that captures images. In any one of Claims 5 thru | or 8,
And a mechanism for moving the light source.
The control device moves the light emitting source to form the first region and the second region. A semiconductor manufacturing device. The claim 1, further comprising:
A die supply unit having a wafer ring holder for holding a dicing tape to which the die is attached;
The said control apparatus images the die | dye stuck on the said dicing tape using the said imaging device and the said illuminating device. Semiconductor manufacturing apparatus. The claim 1, further comprising:
A bonding head for bonding the die onto a substrate or an already bonded die;
The said control apparatus images the die | dye bonded on the said board | substrate or die | dye using the said imaging device and the said illuminating device. Semiconductor manufacturing apparatus. The claim 1, further comprising:
A pickup head for picking up the die;
An intermediate stage on which the picked-up die is placed;
With
The said control apparatus images the die | dye mounted on the said intermediate | middle stage using the said imaging device and the said illuminating device. Semiconductor manufacturing apparatus. (A) preparing the semiconductor manufacturing apparatus according to any one of claims 1 to 10;
(B) carrying in a wafer ring holder for holding a dicing tape with a die attached thereto;
(C) carrying in the substrate;
(D) picking up the die;
(E) bonding the picked-up die onto the substrate or a die already bonded to the substrate;
A method for manufacturing a semiconductor device. In claim 15,
In the step (d), the picked-up die is placed on an intermediate stage,
The step (e) is a method of manufacturing a semiconductor device that picks up a die placed on the intermediate stage. The method of manufacturing a semiconductor device according to claim 15, further comprising: (g) inspecting an appearance of the die using the imaging device and the illumination device before the step (d). The method of manufacturing a semiconductor device according to claim 15, further comprising: (h) after the step (e), inspecting an appearance of the die using the imaging device and the illumination device. The semiconductor device according to claim 16, further comprising: (i) a step of inspecting an appearance of the die using the imaging device and the illumination device after the step (d) and before the step (e). Manufacturing method.

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