JP7225337B2 - Semiconductor manufacturing equipment and semiconductor device manufacturing method - Google Patents

Description

The present disclosure relates to semiconductor manufacturing equipment and is applicable, for example, to a die bonder equipped with a camera for recognizing dies.

When semiconductor chips are manufactured by dicing a disk-shaped wafer in advance, cracks extending inward from the cut surface may occur in the semiconductor chips due to cutting resistance during dicing. After singulation, the semiconductor chips are inspected for the presence of cracks, etc., and are judged to be good or bad as products (for example, Japanese Unexamined Patent Application Publication No. 2008-98348).

JP-A-2008-98348 JP 2008-66452 A

If anomaly detection on the surface of a semiconductor chip (die) is performed by binarizing a captured image or using an image difference method with a non-defective product, a crack with a width of less than one pixel cannot be found.
An object of the present disclosure is to provide a technique capable of improving crack recognition accuracy.
Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

A brief outline of a representative one of the present disclosure is as follows.
That is, a semiconductor manufacturing apparatus includes an imaging device that images a die, a lighting device arranged on a line connecting the die and the imaging device, and a control device that controls the imaging device and the lighting device. The control device illuminates a portion 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. do.

According to the above semiconductor manufacturing apparatus, it is possible to improve the recognition accuracy of cracks.

Schematic top view showing a configuration example of a die bonder A diagram for explaining a schematic configuration when viewed from the direction of arrow A in FIG. Appearance perspective view showing the configuration of the die supply unit in FIG. Schematic cross-sectional view showing the main part of the die supply part of FIG. Block diagram showing a schematic configuration 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 the scanning operation A diagram showing an example of a unique part (selection area) Diagram showing examples of registered images and similar images Flowchart for explaining continuous construction start operation Diagram showing image of die with cracks A diagram showing an image obtained by binarizing the image of FIG. A diagram showing an image of a good die A diagram showing the difference between the image in FIG. 11 and the image in FIG. Diagram showing the image when the crack is thick Diagram showing the image when the crack is thin A diagram showing an image for explaining an indirect crack detection method. A diagram for explaining the optical system of the wafer supply unit. Diagram for explaining the light source of coaxial illumination Diagram for explaining the indirect crack detection method A diagram showing an image for explaining an indirect crack detection method. A diagram showing an image for explaining an indirect crack detection method. A diagram for explaining the light emitting surface and the shielding surface of the lighting. Diagram for explaining the lighting section Diagram for explaining surface emitting lighting Captured image of crack

As part of the manufacturing process of a semiconductor device, there is a process of mounting a semiconductor chip (hereinafter simply referred to as a die) on a wiring board, lead frame, etc. (hereinafter simply referred to as a substrate) and assembling a package. Part of the process includes a process of dividing a semiconductor wafer (hereinafter simply referred to as a wafer) into dies and a bonding process of mounting the divided dies on a substrate. A semiconductor manufacturing apparatus used in the bonding process is a die bonder.

A die bonder is a device that bonds (mounts and bonds) 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, a suction nozzle called a collet is used to pick up the die by suction from the wafer, convey it onto the substrate, apply a pressing force, and heat the bonding material. By doing so, the operation (work) of performing bonding is performed repeatedly. The collet is a holder that has a suction hole, sucks air, and holds the die by suction, and has approximately the same size as the die.

<Embodiment>
A semiconductor manufacturing apparatus according to an embodiment will be described below. In addition, the code|symbol in a parenthesis is an example, and is not limited to this.
A semiconductor manufacturing apparatus (10) includes an imaging device (ID) for imaging a die (D), a lighting device (LD) arranged on a line connecting the die (D) and the imaging device (ID), and an imaging device ( ID) and a controller (8) for controlling the lighting device (LD). A control device (8) illuminates a portion of the die (D) with a lighting device (LD) and provides light (B), dark (S) and a gradation between light (B) and dark (S). A part (M) is formed on a die (D), and an imaging device (ID) images the die (D).
As a result, it is possible to detect cracks with a width of less than one pixel that cannot be detected by binarization or the image difference method with non-defective products on the surface of the die, and improve the accuracy of crack recognition. be.

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 descriptions may be omitted. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is only an example, and the interpretation of the present invention is not intended. It is not limited.

FIG. 1 is a top view showing an outline of a die bonder according to an embodiment. 2A and 2B are diagrams 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 can be broadly divided into a supply unit 1 that supplies dies D to be mounted on a substrate 9 on which one or more product areas (hereinafter referred to as package areas P) that will become one final package (hereinafter referred to as package area P) are printed; It has an intermediate stage section 3, a bonding section 4, a transfer section 5, a substrate supply section 6, a substrate unloading section 7, and a control section 8 that monitors and controls the operation of each section. The Y-axis direction is the front-back direction of the die bonder 10, and the X-axis direction is the left-right direction. The die supply unit 1 is arranged on the front side of the die bonder 10, and the bonding unit 4 is arranged 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 has a wafer holder 12 that holds the wafer 11 and a push-up unit 13 that pushes up the die D from the wafer 11 as indicated by a dotted line. The die supply unit 1 is moved in the XY directions by driving means (not shown) to move the die D to be picked up 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 driving unit 23 of the pickup head that moves the pickup head 21 in the Y direction, and each driving unit (not shown) that moves the collet 22 up and down, rotates, and moves in the X direction. , have The pick-up head 21 has a collet 22 (see also FIG. 2) that sucks and holds the pushed-up die D at its tip. The pickup head 21 has respective drive units (not shown) that move the collet 22 up and down, rotate it, and move it in the X direction.

The intermediate stage section 3 has 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 it onto the package area P of the substrate 9 that is conveyed, or stacks it on the die already bonded onto the package area P of the substrate 9. Bonding in shape. The bonding unit 4 includes a bonding head 41 having a collet 42 (see also FIG. 2) that sucks and holds the die D at its tip, as in the pickup head 21, a Y driving unit 43 that moves the bonding head 41 in the Y direction, and a substrate. 9, and a substrate recognition camera 44 for capturing an image of a position recognition mark (not shown) of the package area P and recognizing the bonding position.
With such a configuration, the bonding head 41 corrects the pick-up position/orientation based on the imaging data of the stage recognition camera 32, picks up the die D from the intermediate stage 31, and picks up the substrate based on the imaging data of the substrate recognition camera 44. Bond die D to

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

The control unit 8 includes a memory that stores a program (software) for monitoring and controlling 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 section 1 will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 is a diagram showing an external perspective view of a die supply section. FIG. 4 is a schematic cross-sectional view showing the main part of the die supply section.

The die supply unit 1 includes a wafer holding table 12 that moves horizontally (XY directions) and a push-up unit 13 that moves vertically. The wafer holder 12 has an expand ring 15 that holds the wafer ring 14, and a support ring 17 that horizontally positions the dicing tape 16 held by the wafer ring 14 and having the plurality of dies D adhered thereto. The thrusting unit 13 is arranged 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 by the wafer ring 14 is stretched to widen the distance between the dies D, and the dies D are pushed up from below by the push-up unit 13, thereby improving pick-up performance of the dies D. As the thickness of the die is reduced, the adhesive that bonds the die to the substrate changes from a liquid to a film. there is For wafer 11 with die attach film 18 , dicing is performed on wafer 11 and die attach film 18 . Therefore, in the peeling process, the wafer 11 and the die attach film 18 are peeled off from the dicing tape 16 . Note that the following description ignores the presence of the die attach film 18 .

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

The control unit 8 will be described with reference to FIG. 5 . FIG. 5 is a block diagram showing a schematic configuration of the control system. The control system 80 includes a control section 8 , a drive section 86 , a signal section 87 and an optical system 88 . The control unit 8 is roughly divided into a control/arithmetic unit 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 source unit 85 . The storage device 82 includes a main storage device 82a comprising a RAM storing processing programs and the like, and an auxiliary storage device 82b comprising an HDD storing control data and image data required for control. and The input/output device 83 includes a monitor 83a for displaying device status, information, etc., a touch panel 83b for inputting operator's instructions, a mouse 83c for operating the monitor, and an image capturing device 83d for capturing image data from the optical system 88. and have The input/output device 83 includes a motor control device 83e for controlling a drive unit 86 such as an XY table (not shown) of the die supply unit 1 and ZY drive shafts of the bonding head table, various sensor signals, an illumination device, and the like. and an I/O signal control device 83f for taking in or controlling a signal from a signal section 87 such as a switch. Optical system 88 includes wafer recognition camera 24 , stage recognition camera 32 , and substrate recognition camera 44 . The control/arithmetic unit 81 takes in necessary data through a bus line 84, performs arithmetic operations, controls the pickup head 21 and the like, and sends information to the monitor 83a and the like.

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 capturing device 83d. The control/arithmetic unit 81 is used to position the package area P of the die D and the substrate 9 and to inspect the surfaces of the die D and the substrate 9 using software programmed based on the stored image data. Based on the positions of the die D and the package area P of the substrate 9 calculated by the control/arithmetic unit 81, the software drives the drive unit 86 via the motor control unit 83e. By this process, the die is positioned on the wafer, and the pickup section 2 and the driving section of the bonding section 4 are operated to bond the die D onto the package area P of the substrate 9 . The wafer recognition camera 24, the stage recognition camera 32, and the substrate recognition camera 44 used are grayscale, color, etc., and quantify the light intensity.

FIG. 6 is a flow chart for explaining the 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 ready for pickup of the die D. The wafer is transported to a reference position (wafer loading (process P1)). Next, the control unit 8 finely adjusts the arrangement position of the wafer 11 from the image acquired by the wafer recognition camera 24 so that it 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 horizontally holds it, thereby placing the die D to be picked up first at the pick-up position (die transfer). (Step P2)). The wafer 11 is inspected for each die in advance by an inspection device such as a prober, and map data indicating good or bad for each die is generated and stored in the storage device 82 of the control unit 8 . The map data is used to determine whether the die D to be picked up is a good product or a defective product. If the die D is defective, the control unit 8 moves the wafer holding table 12 on which the wafer 11 is mounted at a predetermined pitch, arranges the die D to be picked up next, at the pickup position, and determines that the die D is defective. Skip die D of .

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

Next, the control unit 8 inspects the surface of the die D from the image acquired by the wafer recognition camera 24 (process P4). The 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, and when it is determined that there is no problem with the surface of the die D, the process proceeds to the next step (process P9 described later), but it is determined that there is a problem. In this case, the surface image is visually checked, and if there is a problem, skip processing is performed, and if there is no problem, the next step is performed. The skip processing skips the process P9 and subsequent steps for the die D, moves the wafer holding table 12 on which the wafer 11 is placed, at a predetermined pitch, and places the die D to be picked up next 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 conveying claws 51 that grasp and convey the substrate 9 to the bonding position (substrate conveying (process P6)).

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

Next, the control unit 8 inspects the surface of the package area P of the board 9 from the image acquired by the board recognition camera 44 (process P8). The details of the board 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 with the surface of the package area P of the substrate 9, it proceeds to the next step (step P9 described later). When it is determined that there is a problem, the surface image is visually checked, and if there is a problem, skip processing is performed. The skip processing skips the step P10 and subsequent steps to the corresponding tab in the package area P of the board 9, and registers the defect in the board processing start information.

After accurately placing the die D to be picked up at the pickup position, the control unit 8 picks up the die D from the dicing tape 16 with the pickup head 21 including the collet 22 (die handling (process P9)), and transfers it to the intermediate stage 31. Place the die ((process P10). The control unit 8 detects the posture deviation (rotational deviation) of the die placed on the intermediate stage 31 by imaging the die with the stage recognition camera 32 (process P11). If there is a posture deviation, the intermediate stage 31 is rotated in 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 inspects the surface of the die D from the image acquired by the stage recognition camera 32 (process P12). The 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, and when it is determined that there is no problem with the surface of the die D, the process proceeds to the next step (step P13 described later), but it is determined that there is a problem. In this case, the surface image is visually checked, and if there is a problem, skip processing is performed, and if there is no problem, the next step is performed. The skip process skips the die D step P13 and thereafter, moves the wafer holding table 12 on which the wafer 11 is placed, at a predetermined pitch, and places the die D to be picked up next at the pick-up 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 (die attach) to the package area P of the substrate 9 or a die already bonded to the package area P of the substrate 9. ((Step P13)).

After bonding the die D, the control unit 8 inspects whether the bonding position is accurate (inspection of the relative position of the die and the substrate (process P14)). At this time, the center of the die and the center of the tab are determined in the same manner as the alignment of the die, which will be described later, and it is inspected whether the relative positions are correct.

Next, the control unit 8 inspects the surface 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 if it is determined that there is no problem with the surface of the bonded die D, it proceeds to the next step (step P9 to be described later), but there is a problem. If it is determined as such, the surface image is visually checked, and if there is a problem, skip processing is performed, and if there is no problem, the processing of the next step is performed. In the skip process, a defect is registered in the board processing start information.

Thereafter, the dies D are bonded one by one to the package area P of the substrate 9 according to the same procedure. When the bonding of one substrate is completed, the substrate conveying claw 51 moves the substrate 9 to the substrate unloading section 7 (substrate transportation (process P16)), and the substrate 9 is transferred to the substrate unloading section 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 (process P9). After picking up all the dies D except the defective ones, the dicing tape 16 and the wafer ring 14 holding the dies D in the shape of the wafer 11 are unloaded from the wafer cassette (step P18).

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

The die positioning algorithm mainly uses template matching and is operated by a generally known normalized correlation formula. The result is defined as the match rate. Template matching includes reference learning copying motion and continuous starting motion.

First, the copying operation will be explained. The control unit 8 transports the reference sample to the pickup position (step S1). The control unit 8 acquires the image PCr of the reference sample 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 within the image through the human interface (touch panel 83b or mouse 83c) (step S3). The control unit 8 stores the positional relationship (coordinates) between the selected unique portion (selection area) UA and the reference sample in the storage device 82 (step S4). The control unit 8 stores the image (template image) PT of the selected area in the storage device 82 (step S5). A reference workpiece image and its coordinates are stored in a storage device.

Next, continuous operation will be described. The control unit 8 transports the members (product wafers) to the pick-up position for starting continuous processing (step S11). The control unit 8 acquires the image PCn of the product die with the wafer recognition camera VSW (step S2). As shown in FIG. 9, the control unit 8 compares the template image PT saved 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 portion (step S13). . The coordinates are compared with the coordinates measured by the reference sample, and the position of the product die (the offset between the image PTn and the template image PT) is calculated (step S14).
Die visual inspection and recognition (detection of abnormalities such as cracks and foreign matter) will be described with reference to FIGS. FIG. 11 is a diagram showing an image of a die with cracks. FIG. 12 is a diagram showing an image obtained by binarizing the image of FIG. FIG. 13 is a diagram showing an image of a non-defective die. FIG. 14 is a diagram showing the difference between the image in FIG. 11 and the image in FIG.

Methods such as binarization and image difference method are used to detect anomalies on the die surface. An image PC2 (FIG. 12) is generated by binarizing the image PCa (FIG. 11) of the die having the crack CR, and the abnormal portion (crack CR) is detected. An image PCa-n is generated by taking the difference between the image PCa (FIG. 11) of the die with the crack CR and the image PCn (FIG. 13) of the non-defective die to detect the crack CR.

Problems of the above method will be described with reference to FIGS. 15 and 16. 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 observed, and as shown in FIG. 15, if the crack CR1 of the image PCa1 is thick, it can be detected, but as shown in FIG. Otherwise, it is difficult to detect. That is, the above method has the following problems.
(1) A crack with a width of less than 1 pixel cannot be detected If the crack width is less than 1 pixel and the crack is imaged, the image will fade and become unrecognizable. Considering the crack direction and the like, it cannot be reliably detected unless the width is substantially three pixels or more.
(2) Susceptibility to die surface pattern When the die surface has a complicated pattern, it becomes difficult to distinguish it from cracks running on the surface.
(3) It is difficult to control the brightness of cracks It is difficult to photograph only cracks brightly or darkly.

The above issues are caused by directly observing cracks in the same way as when recognizing die positioning. A detection method was devised.

FIG. 17 is an image for explaining the indirect crack detection method. The indirect detection method for cracks is a method that captures changes that occur in the surroundings when cracks are present. For example, as shown in FIG. 17, if the brightness of the die image PC changes with the crack CR as the boundary, the crack can be captured 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. Specific means of the crack indirect detection method will be described below.

First, the board recognition camera will be described with reference to FIG. FIG. 18 is a diagram for explaining the optical system of the bonding section, and shows the arrangement of the substrate recognition camera and the illumination section for irradiating the die with light for photographing an image.
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, through which the image of the main surface of the die D is captured. It is configured to
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 having a surface emitting illumination (light source) SL and a half mirror (half-transmissive mirror) HM inside is arranged. ing. Irradiation light from the surface emitting illumination SL is reflected by the half mirror HM on the same optical axis as the imaging unit ID, and the die D is irradiated with the light. The scattered light irradiated to the die D on the same optical axis as the imaging unit ID is reflected by the die D, and the specularly reflected light thereof is transmitted through the half mirror HM and reaches the imaging unit ID to form an image of the die D. 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 section LD have been described, the same applies to the stage recognition camera 32 and its illumination section, and the wafer recognition camera 24 and its illumination section.

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

If the light source is placed as it is, the coaxial illumination blocks the optical path between the die and the camera. Therefore, as shown in FIG. 19, a half mirror HM is placed to place the light source SL at a position away from the optical path. However, from the viewpoint of the die D, it can also be considered that the light source (virtual light source) VSL exists at a virtual position between the die and the camera due to the half mirror HM. However, the virtual light source VSL has a lower luminous intensity than the actual light source SL. Hereinafter, the position of the light source for coaxial illumination is denoted by a virtual light source VSL.

This embodiment takes advantage of the smaller angular differences that naturally occur in through cracks. Since the angle difference is small, it becomes difficult to detect, so an illumination method and a method for detecting it are used to highlight a slight step of the crack portion penetrating the die.

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

As shown in FIG. 20, part of the light emitting surface of the virtual light source VSL is shielded by, for example, a shielding plate SHL. As shown in FIGS. 20 and 21, a shaded area S is generated by the shielded area, and an intermediate area M with a gradation is generated at the boundary between the shaded area B and the non-shaded area B. As shown in FIGS. If a crack occurs in this intermediate region M, a clear difference in brightness tends to appear at the boundary surface of the crack CR as shown in FIG. 22(A). The image of the crack CR is captured by a slight step.

An image obtained by this method (FIG. 22A) is processed with an existing pattern as shown in FIG. The crack portion can be separated from the gradation area.

The image after separation (Fig. 22(C)) is subjected to differential processing with the image (Fig. 22(D)) which is processed in the same way with a crack-free (non-defective) die. can be separated. This can be detected by confirming the gradation of the difference-processed image (difference image) because the images of the die with cracks and the image of the non-defective die are not the same. Thereby, the position and length of the crack portion can be detected. In addition to the difference image, edge detection (including the use of spatial filters such as Sobel filters and differential filters) to detect unintended edges in the image, and brightness data to detect changes in the average brightness and histogram of the specified area. may be used.

23A and 23B are diagrams for explaining the light emitting surface and the shielding surface of the illumination, FIG. 23A is a diagram showing a preferable example, and FIG. 23B is a diagram showing an unpreferable example.

In FIG. 23A, the boundary plane 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 uniform. 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 there is no lightness on the boundary surface and that there is no unevenness on the light emitting surface and the shielding surface.

The indirect crack 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 a contrast to the brightness on both sides of the boundary surface, and detects a minute width crack. make it easier. Normally (for example, direct detection type die positioning recognition), coaxial illumination with sufficient light emitting surface area is provided to see the full view of the die. The light emitting 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 switch between 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 between light-emitting area and light-shielding area by partially turning on/off LEDs arrayed in a plane (d) Movement of illumination that irradiates the die (e) Movement of camera that captures cracks (f) Discontinuous irradiation The die is moved with respect to the boundary surface of the area using, for example, an intermediate stage.
etc. In the following, the control of the light emitting surface will be explained by taking (c) partial ON/OFF of the planarly arranged LEDs as an example. FIG. 24 is a perspective view of the lighting section. FIG. 25 is a cross-sectional view of a surface emitting illumination. FIG. 26 is a diagram showing a captured image of cracks.

The surface-emitting illumination SL in the illumination unit LD is a surface-emitting type LED light source, and includes an LED substrate SL1 having LEDs arranged in a plane, a diffusion plate SL2 provided facing the LED substrate SL1, and the LED substrate SL1 and the 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 area SL1A and a lower second area 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 LEDs in the first region SL1A are turned on, the LEDs in the second region SL1B are turned off, and the light emitting surface area is reduced to form the light emitting surface and the shielding surface. Thereby, the same as in FIG. 20 can be achieved.

As described above, if a shielding plate is inserted inside the surface 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 reflective surface boundaries of the revealed illumination can be visualized. At this time, it is preferable that the boundary of the light-emitting surface of the surface of the diffusion plate for diffusing light is well established.

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 to change the regions of 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 transmissive/non-transmissive region of the liquid crystal panel.

Visual inspection of cracks is performed in at least one of the die supply section, the intermediate stage, and the bonding stage where the die position is recognized. It is more preferable to carry out in place. If performed in the intermediate stage, cracks that could not be detected in 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 the bonding stage is performed, cracks that could not be detected in the die supply unit and the intermediate stage (cracks that did not become apparent before the bonding process) or cracks that occurred after the bonding process can be removed by bonding the next die. It can be detected before or before substrate ejection.

The invention made by the present inventors has been specifically described above based on the embodiments and examples, but it should be noted that the present invention is not limited to the above-described embodiments and examples, and can be modified in various ways. Not even.

For example, in the embodiments, the coaxial illumination is of the type arranged between the objective lens and the die, but it may be of the type inserted into the lens.
Further, in the embodiment, the die visual inspection recognition is performed after the die position recognition, but the die position recognition may be performed after the die visual inspection recognition.
Also, although the DAF is attached to the back surface of the wafer in the embodiment, the DAF may be omitted.
Also, although one pickup head and one bonding head are provided in the embodiment, two or more of each may be provided. Also, although the embodiment includes an intermediate stage, the intermediate stage may be omitted. In this case, the pickup head and the bonding head may be used together.
Also, in the embodiment, the die is bonded with the surface facing up, but after the die is picked up, the die may be turned over and bonded with the back surface of the die facing up. In this case, no intermediate stage may be provided. This device is called a flip chip bonder.
Moreover, although the bonding head is provided in the embodiment, the bonding head may be omitted. In this case, the picked-up die is placed on a container or the like. This device is called a pickup device.

Further, readjustment and reinspection of the light-emitting area and light-shielding area may be performed in accordance with the direction of the previously detected crack. Thereby, the detection rate can be improved.

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

Claims (12)

an imaging device that images the die;
surface-emitting lighting that emits scattered light;
a shielding plate disposed above the die and causing a change in brightness on the surface of the die;
a control device that controls the imaging device;
with
The semiconductor manufacturing apparatus, wherein the control device is configured to change a bright portion, a dark portion, and a gradation portion between the bright portion and the dark portion on the surface of the die, and to image the die with the imaging device. In the semiconductor manufacturing apparatus of claim 1,
The semiconductor manufacturing apparatus, wherein the control device is configured to image the die with the imaging device and determine whether or not there is a crack based on the image of the gradation portion. In the semiconductor manufacturing apparatus of claim 2,
The semiconductor manufacturing apparatus, wherein the control device is configured to change a bright portion, a dark portion, and a gradation portion between the bright portion and the dark portion on the surface of the die by moving the shielding plate. In the semiconductor manufacturing apparatus of claim 3,
A semiconductor manufacturing apparatus comprising a lighting device having a light-emitting surface and a shielding surface formed by shielding the light-emitting surface with the shielding plate. The semiconductor manufacturing apparatus according to claim 4, further comprising:
A die supply unit having a wafer ring holder that holds a dicing tape to which the die is attached,
A semiconductor manufacturing apparatus, wherein the control device is configured to capture an image of the die attached to the dicing tape using the imaging device and the illumination device. The semiconductor manufacturing apparatus according to claim 4, further comprising:
a bonding head for bonding the die onto a substrate or an already bonded die;
A semiconductor manufacturing apparatus, wherein the controller is configured to image a die bonded on the substrate or die using the imaging device and the illumination device. The semiconductor manufacturing apparatus according to claim 4, further comprising:
a pickup head for picking up the die;
an intermediate stage on which the picked-up die is placed;
with
A semiconductor manufacturing apparatus, wherein the control device is configured to image the die placed on the intermediate stage using the imaging device and the illumination device. (a) a step of preparing the semiconductor manufacturing apparatus according to any one of claims 1 to 4;
(b) picking up the die;
(c) bonding the picked die onto a substrate or a die already bonded to the substrate;
A method of manufacturing a semiconductor device comprising: In the method of manufacturing a semiconductor device according to claim 8,
The step (b) places the picked-up die on an intermediate stage,
The step (c) is a method of manufacturing a semiconductor device in which the die placed on the intermediate stage is picked up. In the method of manufacturing a semiconductor device according to claim 8,
Further, (d) the method of manufacturing a semiconductor device includes, before the step (b), inspecting the appearance of the die using the illumination device having the shielding plate and the imaging device. In the method of manufacturing a semiconductor device according to claim 8,
Further, (e) the method of manufacturing a semiconductor device includes, after the step (c), the step of inspecting the appearance of the die using the illumination device having the shielding plate and the imaging device. In the method of manufacturing a semiconductor device according to claim 9,
(f) a semiconductor device including, after the step (b) and before the step (c), inspecting the appearance of the die using the illumination device having the shielding plate and the imaging device; manufacturing method.

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