Image inspection system

Abstract

Improve detection accuracy. [Solution] The image inspection system according to the embodiment includes: an illumination condition determination unit that determines illumination conditions, including the wavelength spectrum and irradiation angle of the light to be irradiated onto the object to be inspected, according to the object to be inspected; an optical system configured to irradiate the object to be inspected with light having a wavelength spectrum corresponding to the illumination conditions at an angle corresponding to the illumination conditions; and a determination unit that determines whether the shape of the object to be inspected is good or bad based on imaging data of the object to be inspected captured by the light irradiated from the optical system.

Description

Technical Field

[0001] The embodiment relates to an image inspection system.

Background Art

[0002] In the manufacturing process of semiconductor products, an image inspection system for inspecting whether the appearance of a semiconductor product being assembled has a prescribed shape is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] Improve detection accuracy.

Means for Solving the Problems

[0005] The image inspection system according to the embodiment includes an illumination condition determination unit, an optical system, and a determination unit. The illumination condition determination unit determines illumination conditions including the wavelength spectrum and irradiation angle of light irradiated onto the inspection target according to the inspection target. The optical system is configured to irradiate the inspection target with light having a wavelength spectrum corresponding to the illumination conditions at an angle corresponding to the illumination conditions. The determination unit determines whether the shape of the inspection target is good or bad based on the imaging data of the inspection target imaged with the light irradiated from the optical system. [Brief explanation of the drawing]

[0006] [Figure 1] A diagram showing an example of the configuration of a semiconductor device assembly facility equipped with an image inspection system according to the embodiment. [Figure 2] A diagram showing an example of the configuration of a lead frame that is brought into the image inspection system according to this embodiment. [Figure 3] A diagram showing an example of the configuration of the element portion of a lead frame that is brought into the image inspection system according to this embodiment. [Figure 4] A diagram showing an example of the configuration of an image inspection system according to the embodiment. [Figure 5] A diagram showing an example of the arrangement of oblique light illumination in an image inspection system according to the embodiment. [Figure 6] A block diagram showing an example of the hardware configuration of a lighting condition control device included in an image inspection system according to an embodiment. [Figure 7] A block diagram showing an example of the functional configuration of a lighting condition control device included in an image inspection system according to an embodiment. [Figure 8] A diagram showing an example of the data structure of the inspection target information according to the embodiment. [Figure 9] A diagram showing an example of the data structure of a lighting condition database according to an embodiment. [Figure 10] A block diagram showing an example of the hardware configuration of a shape determination device included in an image inspection system according to this embodiment. [Figure 11] A block diagram showing an example of the functional configuration of a shape determination device included in an image inspection system according to this embodiment. [Figure 12] A figure showing a first example of imaging data acquired by the image inspection system according to the embodiment. [Figure 13] This figure shows a second example of imaging data acquired by the image inspection system according to the embodiment. [Figure 14] A flowchart showing an example of lighting condition control processing in an image inspection system according to an embodiment. [Figure 15]A flowchart showing an example of shape determination processing in an image inspection system according to an embodiment. [Modes for carrying out the invention]

[0007] Embodiments will be described below with reference to the drawings. In the following description, components having the same function and configuration will be denoted by the same reference numerals.

[0008] 1. Structure 1.1 Semiconductor Equipment Assembly Facilities Figure 1 shows an example of the configuration of a semiconductor device assembly facility equipped with an image inspection system according to an embodiment.

[0009] The semiconductor device assembly equipment 1 is equipment for automatically assembling semiconductor devices. As shown in Figure 1, the semiconductor device assembly equipment 1 includes an image inspection system 2 and a transport path 3. More specifically, for example, the semiconductor device assembly equipment 1 applies a die attachment paste material 5 onto the bed portion BD of the lead frame 4, performs shape measurement with the image inspection system 2, and mounts individual semiconductor chips onto those judged to be good products. After the bed portion BD of the lead frame 4 with the semiconductor chip mounted is removed from the semiconductor device assembly equipment 1, the following steps are performed: connecting the pad portion of the semiconductor chip to the lead portion LD of the lead frame 4 with a wire, sealing the semiconductor chip, and separating the sealed semiconductor chip from the lead frame 4.

[0010] The image inspection system 2 is a system configured to inspect the shape of the die attach paste material 5 that adheres between the lead frame 4 and the semiconductor chip in the process of placing the above-described semiconductor chip on the lead frame 4. In the image inspection system 2, for example, the lead frame 4 before the die attach paste material 5 is provided on the upper surface and the semiconductor chip is placed is carried into the conveyance path 3 as the inspection target TG. The image inspection system 2 determines whether a die attach paste material 5 having a prescribed shape (such as area and size) is provided on the lead frame 4. When the die attach paste material 5 has the prescribed shape, the image inspection system 2 determines that the die attach paste material 5 has passed the inspection. When the die attach paste material 5 does not have the preset shape, the image inspection system 2 determines that the die attach paste material 5 has failed the inspection. The die attach paste material 5 that has passed the inspection is used for the adhesion between the lead frame 4 and the semiconductor chip in the subsequent process. On the other hand, the die attach paste material 5 that has failed the inspection is not used for the adhesion between the lead frame 4 and the semiconductor chip in the subsequent process.

[0011] FIG. 2 is a diagram showing an example of the configuration of a lead frame carried into the image inspection system according to the embodiment. FIG. 3 is a diagram showing an example of the configuration of an element portion of a lead frame carried into the image inspection system according to the embodiment. FIG. 3 corresponds to an enlarged view of one element portion CP in FIG. 2.

[0012] As shown in FIGS. 2 and, the lead frame 4 is, for example, a metal member in which a plurality of element portions CP corresponding to one semiconductor chip are arranged in a strip shape of m rows and n columns. In FIG. 2, as an example, an example in which 20 element portions CP of 5 rows × 4 columns form one lead frame 4 is shown.

[0013] The element portion CP includes a bed portion BD and a lead portion LD. The bed portion BD is the region electrically connected to the semiconductor chip via a die attachment paste material 5. The lead portion LD is the region bonded to the semiconductor chip via bonding wires. Parts of the bed portion BD and the lead portion LD are covered with a sealing resin that seals the semiconductor chip in subsequent processing. Parts of the bed portion BD and the lead portion LD (hatched regions in Figure 3) may be subjected to a roughening plating treatment to improve adhesion between the surface of the lead frame 4 and the sealing resin. Roughening plating is a treatment that significantly roughens the surface roughness when coating the surface of the lead portion LD with metal, for example. The roughened plated lead portion LD has the property of diffusely reflecting incident light. The surface of the roughened plated lead portion LD includes, for example, at least one metal selected from nickel, palladium, gold, and silver. Furthermore, the reflectance, absorptive rate, and transmittance of the roughened plated lead portion LD may vary depending on the surface roughness of the lead portion LD and the proportion of metal contained in the lead portion LD (i.e., shape and material). The shape and material of the roughened plated lead portion LD may vary depending on the type of lead frame 4, the roughening plate method, etc.

[0014] The die attachment paste material 5 is an adhesive used to fix a semiconductor chip onto the bed portion BD of the lead frame 4. The die attachment paste material 5 includes, for example, an epoxy-based silver paste. The die attachment paste material 5 has a surface shape with a certain curvature. As described above, the die attachment paste material 5 has a relatively high reflectivity because it contains silver as its main component, but it also has the property of scattering light. The reflectivity, absorptive rate, and transmittance of the die attachment paste material 5 can vary depending on the shape and material of the die attachment paste material 5. Furthermore, the shape and material of the die attachment paste material 5 can vary depending on the type of die attachment paste material 5, etc.

[0015] As described above, a single lead frame 4 is provided with multiple die attachment paste materials 5 corresponding to each of the bed sections BD for multiple elements. In Figure 1 and the subsequent Figure 4, for the sake of explanation, a bed section BD for one element and one of the multiple die attachment paste materials 5 provided on the bed section BD are shown.

[0016] 1.2 Image Inspection System Figure 4 shows an example of the configuration of the image inspection system according to the embodiment. Figure 4 is a cross-sectional view of the image inspection system 2 cut in a plane perpendicular to the transport path 3.

[0017] As shown in Figure 4, the image inspection system 2 includes an optical system 10, an illumination condition control device 20, and a shape determination device 40. The optical system 10 includes a housing 11, a half mirror 12, a coaxial incident illumination 13, an oblique illumination 14, a lens 15, and an image sensor 16.

[0018] The housing 11 is positioned between the transport path 3 and the lens 15 and image sensor 16 set. The housing 11 covers the lead frame 4 and die attachment paste material 5, which are the TG to be inspected, as well as the upper part of the transport path 3. The housing 11 incorporates a half mirror 12, coaxial incident illumination 13, and oblique illumination 14 used for imaging the TG to be inspected.

[0019] The portion of the housing 11 that houses the half-mirror 12 and the coaxial incident illumination 13 has, for example, a box shape. The portion of the housing 11 that houses the half-mirror 12 and the coaxial incident illumination 13 is positioned closer to the lens 15 and image sensor 16 than the portion that houses the oblique light illumination 14. An opening H is provided on the surface of the portion of the housing 11 that houses the half-mirror 12 and the coaxial incident illumination 13 that faces the lens 15.

[0020] The half mirror 12 is positioned at a predetermined angle (for example, 45°) with respect to the surface facing the lens 15 (i.e., the surface parallel to the aperture H). The half mirror 12 reflects light that is approximately horizontal to the surface facing the lens 15 into the interior of the housing 11. The half mirror 12 transmits light that is incident perpendicular to the lens 15 to the outside of the housing 11.

[0021] The coaxial incident illumination 13 is a light source positioned parallel to the half mirror 12 in a direction approximately horizontal to the surface opposite the lens 15. That is, the light Le1 emitted from the coaxial incident illumination 13 is reflected by the half mirror 12 in a direction approximately perpendicular to the surface opposite the lens 15 (coaxial direction) and illuminates the object TG to be inspected.

[0022] The coaxial incident illumination 13 has multiple lamp elements 13L. Each of the multiple lamp elements 13L includes, for example, a white light source, a red light source, a green light source, and a blue light source. The red light source, green light source, and blue light source are red, green, and blue LED elements, respectively. The white light source is a combination of an ultraviolet LED element and a phosphor. These four LED elements and phosphor are built into one lamp element 13L. Each of the multiple lamp elements 13L is configured to allow arbitrary dimming of the color (wavelength spectrum) of the light Le1 irradiated from the coaxial incident illumination 13, at least in the visible light region, by independently controlling the output of the four LED elements. The visible light region includes, for example, the range from 400 nm to 800 nm. Although the wavelength spectrum in the visible light region can also be achieved with three elements: a red light source, a green light source, and a blue light source, each of the multiple lamp elements 13L incorporates a white light source that equally covers the entire wavelength region in order to increase output.

[0023] The portion of the housing 11 that houses multiple oblique light illuminators 14 has, for example, a dome shape and is connected at its zenith to a portion that houses a half mirror 12 and coaxial incident light illuminator 13.

[0024] The oblique light illumination 14 is a light source positioned in the dome-shaped portion of the housing 11. The oblique light illumination 14 has multiple lamp elements 14L, and these multiple lamp elements 14L are comprehensively arranged in the dome-shaped portion of the housing 11. In Figure 4, a portion of the multiple lamp elements 14L arranged in a semi-circular arc shape in a certain cross-section of the housing 11 is shown, but the arrangement positions of the multiple lamp elements 14L are not limited to this.

[0025] Figure 5 is a diagram showing an example of the arrangement of oblique lighting in the image inspection system according to the embodiment. Figure 5 is a plan view showing the arrangement of multiple lamp elements 14L when the image inspection system 2 is viewed from the image sensor 16 side to the transport path 3 side.

[0026] Multiple lamp elements 14L are arranged circumferentially on the inner surface of the dome-shaped housing 11 at the same level (height from the transport path 3). The multiple lamp elements 14L are configured to switch between the on state and the off state independently of each other.

[0027] In the examples shown in Figures 4 and 5, two diagonally opposite lamp elements 14L are selectively turned on from among a plurality of lamp elements 14L arranged circumferentially at a certain height from the transport path 3. In this way, the light Le2 emitted from the oblique light illumination 14 is irradiated onto the inspection target TG at an arbitrary angle above the transport path 3. Here, the angle refers to the pair of elevation angle α and azimuth angle β centered on the inspection target TG.

[0028] Each of the multiple lamp elements 14L includes, for example, a white light source, a red light source, a green light source, and a blue light source. The red light source, green light source, and blue light source are red, green, and blue LED elements, respectively. The white light source is a combination of an ultraviolet LED element and a phosphor. These four LED elements and phosphor are built into one lamp element 14L. Each of the multiple lamp elements 14L is configured to allow arbitrary dimming of the color (wavelength spectrum) of the light Le2 emitted from each of the multiple lamp elements 14L, at least in the visible light region, by independently controlling the output of the four LED elements. Although the wavelength spectrum in the visible light region can also be achieved with three elements (red, green, and blue light sources), each of the multiple lamp elements 14L incorporates a white light source that equally covers the entire wavelength range, from the viewpoint of increasing output.

[0029] Of the light Le1 and Le2 irradiated onto the inspection target TG, the light Ld reflected in the coaxial direction passes through the half mirror 12 and enters the lens 15. The lens 15 focuses the incident light Ld and guides it to the image sensor 16.

[0030] The image sensor 16 is, for example, a CCD (charge coupled device) image sensor. The image sensor 16 images the object to be inspected TG based on the light Ld from the housing 11. The image sensor 16 inputs the data obtained by imaging (image data) to the shape determination device 40.

[0031] The lighting condition control device 20 is, for example, an information processing device such as a PC (personal computer). The lighting condition control device 20 independently controls the on and off states of the coaxial incident illumination 13 and the oblique illumination 14. The lighting condition control device 20 also independently controls the on and off states of each of the multiple lamp elements 14L that make up the oblique illumination 14. The lighting condition control device 20 independently controls the intensity of the white light source, red light source, green light source, and blue light source contained in each of the lamp elements 13L and 14L that are set to the on state. As a result, the lighting condition control device 20 can adjust the lighting conditions of the light irradiated onto the inspection target TG. Here, the lighting conditions include the irradiation angle (position) and the wavelength spectrum of the irradiated light.

[0032] The shape determination device 40 is, for example, an information processing device such as a PC. Based on the imaging data input from the image sensor 16, the shape determination device 40 detects the die attachment paste material 5 provided on the lead frame 4. The shape determination device 40 determines whether the detected die attachment paste material 5 has a specified shape or not.

[0033] With the above configuration, the image inspection system 2 can determine the quality of the die attachment paste material 5 from the perspective of placing the semiconductor chip on the lead frame 4.

[0034] 1.3 Lighting Condition Control Device Figure 6 is a block diagram showing an example of the hardware configuration of a lighting condition control device included in an image inspection system according to an embodiment.

[0035] As shown in Figure 6, the lighting condition control device 20 includes, for example, a control circuit 21, storage 22, a communication module 23, an interface 24, a drive 25, and a storage medium 26.

[0036] The control circuit 21 is a circuit that controls all components of the lighting condition control device 20 as a whole. The control circuit 21 includes a CPU (central processing unit), RAM (random access memory), and ROM (read-only memory), etc. The CPU of the control circuit 21 controls the entire lighting condition control device 20 according to the program stored in the ROM of the control circuit 21. The RAM of the control circuit 21 has a work area for the CPU of the control circuit 21. The ROM of the control circuit 21 stores programs and other information used by the lighting condition control device 20.

[0037] The storage 22 includes, for example, an HDD (hard disk drive) or an SSD (solid state drive). The storage 22 stores information used by the lighting condition control device 20 for controlling the lighting conditions of the coaxial incident illumination 13 and the multiple oblique illuminations 14.

[0038] The communication module 23 is a circuit used for sending and receiving data between the lighting condition control device 20 and the outside. The communication module 23 may be configured to connect the lighting condition control device 20 to a network (not shown).

[0039] Interface 24 is an interface that manages communication with the user. Interface 24 includes input devices and output devices. Input devices include, for example, a keyboard, a touch panel, and operation buttons. Output devices include, for example, an LCD (liquid crystal display) or EL (electroluminescence) display, a printer, etc. The output device may, for example, display lighting conditions on the display.

[0040] Drive 25 is a device for reading software stored on the storage medium 26. Drive 25 includes, for example, a CD (compact disk) drive or a DVD (digital versatile disk) drive.

[0041] The storage medium 26 is a medium for storing software. The storage medium 26 may also store programs used by the lighting condition control device 20.

[0042] Figure 7 is a block diagram showing an example of the functional configuration of a lighting condition control device included in an image inspection system according to an embodiment.

[0043] As shown in Figure 7, the control circuit 21 of the lighting condition control device 20 functions as a computer comprising an input unit 31, a lighting condition determination unit 32, and an output unit 33. The storage 22 of the lighting condition control device 20 stores the lighting condition DB 34.

[0044] The input unit 31 receives the input of the inspection target information 35. The input unit 31 sends the ID included in the input inspection target information 35 to the lighting condition determination unit 32 as information for determining the lighting conditions to be applied to the inspection target TG.

[0045] The inspection target information 35 is information used to determine the illumination conditions of the light irradiated onto the inspection target TG that is brought into the image inspection system 2. Figure 8 is a diagram showing an example of the data structure of the inspection target information according to the embodiment. As shown in Figure 8, the inspection target information 35 is information in which information such as ID, lead frame type, die attachment paste material type, and plating treatment method are related to each other.

[0046] The ID is an identifier used to identify the TG (Total Gauge) being inspected in relation to the lighting conditions. Specifically, TGs being inspected under common lighting conditions are assigned a common ID. Conversely, TGs being inspected under different lighting conditions are assigned different IDs.

[0047] The lead frame type and the die attachment paste material type include, for example, information on the material of the lead frame and the material of the die attachment paste material.

[0048] The plating method includes information on the plating method applied to the lead frame. Examples of plating types include planar plating and roughening plating. Furthermore, roughening plating may include multiple types, such as methods for applying a roughened plating or methods for roughening a planar plating by applying a chemical treatment.

[0049] When the lighting condition determination unit 32 receives an ID included in the inspection target information 35, it refers to the lighting condition DB 34 and determines the lighting condition corresponding to the ID. Based on the determined lighting condition, the lighting condition determination unit 32 generates control information 36 for the coaxial incident illumination 13 and the multiple oblique illuminations 14. The lighting condition determination unit 32 sends the generated control information 36 to the output unit 33.

[0050] The illumination condition DB34 is a database that stores illumination conditions for detecting the die attachment paste material 5 on the lead frame 4 in the shape determination device 40. The illumination condition DB34 contains illumination conditions that have been previously confirmed to enable detection of the die attachment paste material 5 through experiments, etc., and these are associated with each ID in the database. Figure 9 is a diagram showing an example of the data structure of the illumination condition DB according to the embodiment. As shown in Figure 9, the illumination condition DB34 stores multiple entries, each containing a pair of ID and illumination conditions. Specifically, the illumination conditions include information on the wavelength spectrum and irradiation angle.

[0051] The illumination angle information specifies the (elevation angle, azimuth angle) = (α, β) of the lamp element 14L to be turned on. The number of illumination angles that can be specified may be one or multiple.

[0052] The wavelength spectrum information specifies, for example, the spectrum of light intensity in the visible light region. That is, the wavelength spectrum information is the intensity distribution for each wavelength in the visible light region of the light emitted from the lamp element 14L that is turned on (light from a combination of white, red, green, and blue light sources). The number of wavelength spectra specified in association with a single ID may be one or multiple. The number of wavelength spectra specified in association with a single ID may be specified according to the number of irradiation angles specified in association with that ID.

[0053] The lighting condition determination unit 32 determines which lamp element 14L to turn on based on the irradiation angle information. Then, based on the wavelength spectrum information, the lighting condition determination unit 32 determines the intensity of each of the white light source, red light source, green light source, and blue light source within the lamp element 14L to be turned on. The lighting condition determination unit 32 generates control information 36, which includes the determined information, and sends it to the output unit 33. In the above example, the case in which the intensity distribution of light due to the combination of various light sources irradiated from the lamp element 14L is stored in the lighting condition DB 34 as wavelength spectrum information has been described, but this is not the only case. For example, the lighting condition DB 34 may store a set of information indicating the intensity of each of the various light sources irradiated from the lamp element 14L as wavelength spectrum information. In this case, the lighting condition determination unit 32 can include the wavelength spectrum information in the lighting condition DB 34 directly into the control information 36.

[0054] The output unit 33 outputs the control information 36 generated by the illumination condition determination unit 32 to the coaxial incident light 13 and the multiple oblique light 14. This allows the output unit 33 to selectively turn on the lights positioned at locations corresponding to the determined illumination conditions among the coaxial incident light 13 and the multiple oblique light 14. The output unit 33 can then emit light with a wavelength spectrum corresponding to the determined illumination conditions from the lights that have been turned on.

[0055] 1.4 Shape determination device Figure 10 is a block diagram showing an example of the hardware configuration of a shape determination device included in the image inspection system according to this embodiment.

[0056] As shown in Figure 10, the shape determination device 40 includes, for example, a control circuit 41, storage 42, a communication module 43, an interface 44, a drive 45, and a storage medium 46.

[0057] The control circuit 41 is a circuit that controls all components of the shape determination device 40 as a whole. The control circuit 41 includes a CPU, RAM, and ROM. The CPU of the control circuit 41 controls the entire shape determination device 40 according to the program stored in the ROM of the control circuit 41. The RAM of the control circuit 41 has a working area for the CPU of the control circuit 41. The ROM of the control circuit 41 stores programs and the like used by the shape determination device 40.

[0058] The storage 42 includes, for example, an HDD or an SSD. The storage 42 stores information used in the shape determination process of the die attachment paste material 5 by the shape determination device 40.

[0059] The communication module 43 is a circuit used for sending and receiving data between the shape determination device 40 and the outside. The communication module 43 may be configured to connect the shape determination device 40 to a network (not shown).

[0060] Interface 44 is an interface that manages communication with the user. Interface 44 includes input devices and output devices. Input devices include, for example, a keyboard, a touch panel, and operation buttons. Output devices include, for example, an LCD or EL display, a printer, etc. The output device may, for example, display the results of shape determination processing on the display.

[0061] Drive 45 is a device for reading software stored on the storage medium 46. Drive 45 includes, for example, a CD drive or a DVD drive.

[0062] The storage medium 46 is a medium for storing software. The storage medium 46 may also store a program used by the shape determination device 40.

[0063] Figure 11 is a block diagram showing an example of the functional configuration of a shape determination device included in an image inspection system according to this embodiment.

[0064] As shown in Figure 11, the control circuit 41 of the shape determination device 40 functions as a computer comprising an input unit 51, a detection unit 52, a determination unit 53, and an output unit 54. The storage 42 of the shape determination device 40 stores reference data 55.

[0065] The input unit 51 receives the image data 56 generated by the image sensor 16. The input unit 51 sends the received image data 56 to the detection unit 52.

[0066] The detection unit 52 detects the portion of the lead frame 4, as captured in the imaging data 56, where the die attachment paste material 5 is applied. The detection unit 52 detects the boundary between the lead frame 4 and the die attachment paste material 5 based, for example, on the contrast in the imaging data 56 (i.e., the difference in brightness between the lead frame 4 and the die attachment paste material 5). The detection unit 52 sends information regarding the detected boundary between the lead frame 4 and the die attachment paste material 5 to the determination unit 53.

[0067] Furthermore, from the viewpoint of high-precision detection, it is preferable that the contrast between the lead frame 4 and the die attachment paste material 5 be large.

[0068] Figure 12 shows a first example of imaging data acquired by the image inspection system according to the embodiment. Figure 13 shows a second example of imaging data acquired by the image inspection system according to the embodiment. Figures 12 and 13 correspond to the cases where the detection unit 52 successfully detects the boundary between the lead frame 4 and the die attachment paste material 5, and the cases where it fails, respectively.

[0069] As described above, the lead frame 4 and the die attachment paste material 5 have different materials and shapes, resulting in different characteristics such as reflectance, absorptiveness, and transmittance, as well as different degrees of diffuse reflection. Consequently, the brightness of the parts of the lead frame 4 and the die attachment paste material 5 corresponding to each in the imaging data 56 changes independently of each other in response to changes in illumination conditions. Therefore, as shown in Figure 12, if the illumination conditions are inappropriate, the brightness of the parts corresponding to the lead frame 4 and the brightness of the parts corresponding to the die attachment paste material 5 will either be low or high, making detection more likely to fail. On the other hand, as shown in Figure 13, if the illumination conditions can be set appropriately, it is possible to make either the brightness of the parts corresponding to the lead frame 4 or the brightness of the parts corresponding to the die attachment paste material 5 high and the brightness of the other low, making detection more likely to succeed.

[0070] The determination unit 53 determines whether the die attachment paste material 5 is provided in a specified shape based on information regarding the boundary between the lead frame 4 and the die attachment paste material 5. In making the determination, the determination unit 53 uses, for example, reference data 55 as a comparison target. The reference data 55 is information indicating the specified shape of the die attachment paste material 5. The determination unit 53 compares, for example, the reference data 55 with the detection result from the detection unit 52 and determines whether the difference in shape between the two is less than a threshold. The threshold may be an index such as the radius and area of ​​the die attachment paste material 5. If the difference in shape is less than the threshold, the determination unit 53 determines that the lead frame 4 and die attachment paste material 5 of the TG under inspection are good products (determination OK). If the difference in shape is greater than or equal to the threshold, the determination unit 53 determines that the lead frame 4 and die attachment paste material 5 of the TG under inspection are defective products (determination NG). The determination unit 53 sends the determination result 57 to the output unit 54.

[0071] The output unit 54 outputs the determination result 57 from the determination unit 53 to the outside. This allows the semiconductor equipment assembly equipment 1 to understand that if the determination is OK, it will perform the subsequent processing steps for the inspection target TG. If the determination is NG, the semiconductor equipment assembly equipment 1 will understand that it will not perform the subsequent processing steps for the inspection target TG.

[0072] 2. Operation Next, we will explain the operation of the image inspection system 2.

[0073] 2.1 Lighting Condition Control Processing Figure 14 is a flowchart showing an example of lighting condition control processing in an image inspection system according to an embodiment. Figure 14 shows a flowchart corresponding to lighting condition control processing for one inspection target TG.

[0074] When the TG to be inspected is brought into the enclosure 11 (start), the input unit 31 of the lighting condition control device 20 acquires inspection target information 35 to determine the lighting conditions of the TG to be inspected (S1). One method of acquiring the inspection target information 35 is to acquire the inspection target information 35 manually entered by an operator via the interface 24. Alternatively, the input unit 31 may acquire the inspection target information 35 contained in code information printed or engraved on the TG to be inspected by reading the code information. The inspection target information 35 includes, for example, information that identifies the material and shape of the lead frame 4 and the die attachment paste material 5. More specifically, for example, the inspection target information 35 includes information such as the product name and lot number of the semiconductor device assembled by the TG to be inspected, the material names of the lead frame 4 and the die attachment paste material 5, and the method of roughening plating applied to the lead frame 4.

[0075] The lighting condition determination unit 32 of the lighting condition control device 20 determines lighting conditions, including the irradiation angle and wavelength spectrum of light, based on the inspection target information 35 acquired in the processing of S1 (S2). More specifically, the lighting condition determination unit 32 refers to the lighting condition DB 34 and determines lighting conditions, including the irradiation angle and wavelength spectrum, that can increase the contrast of the parts of the coaxial incident illumination 13 and multiple oblique illuminations 14 that correspond to the lead frame 4 and die attachment paste material 5 in the imaging data 56. The lighting condition determination unit 32 generates control information 36 corresponding to the determined lighting conditions.

[0076] The output unit 33 of the lighting condition control device 20 irradiates the inspection target TG with light using at least one of the coaxial incident light 13 and the multiple oblique light 14, based on the lighting conditions determined in processing S2 (S3). Specifically, the output unit 33 controls the coaxial incident light 13 and the multiple oblique light 14 using control information 36 corresponding to the lighting conditions. As a result, the output unit 33 selectively turns on the light from among the coaxial incident light 13 and the multiple oblique light 14 that is positioned at an angle corresponding to the lighting conditions. The output unit 33 then irradiates the inspection target TG with light of the wavelength spectrum corresponding to the lighting conditions from the turned-on light.

[0077] Once the S3 process is complete, the lighting condition control process ends (end).

[0078] 2.2 Shape determination process Figure 15 is a flowchart showing an example of shape determination processing in an image inspection system according to an embodiment. Figure 15 shows a flowchart corresponding to the shape determination processing for one inspection target TG.

[0079] When light corresponding to the illumination conditions is irradiated onto the object to be inspected (start), the input unit 51 of the shape determination device 40 acquires imaging data 56 from the image sensor 16 (S11).

[0080] The detection unit 52 of the shape determination device 40 detects the portion of the lead frame 4, which is captured in the imaging data 56 obtained in the process of S11, where the die attachment paste material 5 is applied (S12).

[0081] The detection unit 52 of the shape determination device 40 determines whether the detection of the die attachment paste material 5 by the process in S12 was successful (S13).

[0082] If the detection of the die attachment paste material 5 is successful (S13; yes), the determination unit 53 of the shape determination device 40 determines whether the shape of the die attachment paste material 5 detected in the process of S13 is normal or not (S14).

[0083] If the shape of the die attachment paste material 5 is normal (S14; yes), the output unit 54 of the shape determination device 40 outputs information indicating that the determination is OK (S15).

[0084] If detection of the die attachment paste material 5 fails (S13; no), or if the shape of the die attachment paste material 5 is not normal (S14; no), the output unit 54 outputs information indicating a judgment failure (S16).

[0085] After processing in S15 or S16, the shape determination process ends (end). A semiconductor chip will be mounted on the bed portion BD where the die attachment paste material 5 is provided and determined to be OK in processing S15. A semiconductor chip will not be mounted on the bed portion BD where the die attachment paste material 5 is provided and determined to be NG in processing S15.

[0086] 3. Effects according to the embodiment According to the embodiment, the illumination condition determination unit 32 determines illumination conditions, including the wavelength spectrum and irradiation angle of the light to be irradiated onto the TG to be inspected, according to the TG to be inspected. The optical system 10 is configured to irradiate the TG to be inspected with light having a wavelength spectrum corresponding to the illumination conditions, at an angle corresponding to the illumination conditions. As a result, the determination unit 53 can determine the quality of the shape of the TG to be inspected based on the imaging data 56 captured under illumination conditions optimized to maximize the brightness difference between the lead frame 4 and the die attachment paste material 5 for each TG to be inspected. Therefore, the detection accuracy of the die attachment paste material 5 can be improved.

[0087] To elaborate, a lead frame plated to have a flat top surface will specularly reflect light from coaxial incident illumination, while the die attachment paste material will diffusely reflect light. Therefore, in imaging data obtained using coaxial incident illumination, the brightness of a lead frame without roughening plating and the die attachment paste material applied to that lead frame can easily be made to differ significantly. However, a lead frame with a roughening plating on its top surface will diffusely reflect light due to its uneven shape. Therefore, in imaging data obtained using coaxial incident illumination, both the roughening plating lead frame and the die attachment paste material applied to that lead frame will have lower brightness, potentially reducing detection accuracy. In addition, the degree of diffuse reflection and reflectance vary depending on the shape and material. Consequently, even with a roughening plating lead frame, the optimal illumination conditions may differ depending on the type of lead frame and the method of roughening plating.

[0088] According to this embodiment, the illumination condition determination unit 32 is configured to determine different illumination conditions for two inspection targets TG in which at least one of the following is different: the type of lead frame 4, the type of die attachment paste material 5, and the roughening plating method. As a result, if the lead frame is not roughened, the illumination condition determination unit 32 can determine illumination conditions that cause the optical system 10 to function as coaxial incident illumination. If the lead frame is roughened, the illumination condition determination unit 32 can determine illumination conditions that cause the optical system 10 to function as oblique illumination. Furthermore, even if the lead frame is roughened, the illumination condition determination unit 32 can select the optimal illumination conditions based on the inspection target information 35.

[0089] 4. Variations, etc. The above-described embodiments can be modified in various ways.

[0090] In the embodiments described above, the case in which coaxial incident illumination 13 and multiple oblique illuminations 14 are comprehensively arranged within the housing 11 was explained, but the invention is not limited to this. For example, one or more illuminations may be intermittently arranged within the housing 11. In this case, one or more illuminations arranged within the housing 11 may be configured to be movable to any position depending on the illumination conditions. This makes it possible to achieve optimal irradiation angle and wavelength spectrum for each inspection target TG, similar to the embodiments described above.

[0091] Furthermore, in the embodiment described above, the case in which the detection of the die attachment paste material 5 fails in the detection process of S13 (S13; no) and a judgment of NG is output was explained, but it is not limited to this. For example, if the detection of the die attachment paste material 5 fails in the process of S13 (S13; no), the image inspection system 2 may change the lighting conditions, acquire imaging data again, and perform the detection process again. Here, the new lighting conditions to be applied may be lighting conditions stored in the lighting condition DB34, or they may be lighting conditions that have been fine-tuned from the lighting conditions that failed the detection process.

[0092] Furthermore, although the above-described embodiment described a case where the lighting condition control device 20 and the shape determination device 40 are separate devices, the invention is not limited to this. For example, the lighting condition control device 20 and the shape determination device 40 may be implemented as a single device, or they may be formed integrally with the housing 11.

[0093] Furthermore, although the above-described embodiment explains the case in which the programs for performing the lighting condition control process and the shape determination process are executed by the lighting condition control device 20 and the shape determination device 40, respectively, it is not limited to this. For example, the programs for performing the lighting condition control process and the shape determination process may be executed on computing resources on a cloud configured in a network (not shown).

[0094] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0095] 1… Semiconductor equipment assembly facilities 2…Image inspection system 3…Conveyor path 4… Lead frame 5…Dia attachment paste material 10...Optical system 11…Cabinet 12… Half-mirror 13…Coaxial epi-illumination 14… Oblique lighting 15... Lens 16…Image sensor 20…Lighting condition control device 40...Shape determination device 21,41…control circuit 22,42... storage 23,43…Communication module 24,44… Interface 25,45... Drive 26,46…Storage medium 31, 51… Input section 32...Lighting condition determination unit 33, 54… Output section 34…Lighting condition DB 35…Information to be tested 36…Control Information 52...Detection unit 53…Judgment section 55…Reference data 56…Imaging data 57…Judgment result

Claims

1. A lighting condition determination unit determines lighting conditions, including the wavelength spectrum and irradiation angle of the light to be irradiated onto the object to be inspected, according to the object to be inspected. An optical system configured to irradiate the object to be inspected with light having a wavelength spectrum corresponding to the illumination conditions at an angle corresponding to the illumination conditions, A determination unit that determines whether the shape of the object to be inspected is good or bad based on the imaging data of the object to be inspected captured by light irradiated from the optical system, An image inspection system equipped with [specific features / equipment].

2. The subject of inspection includes the adhesive on the lead frame, The image inspection system according to claim 1.

3. The optical system is configured to function as oblique light illumination when the lead frame is subjected to roughening plating. The image inspection system according to claim 2.

4. The illumination condition determination unit is configured to determine different illumination conditions for two inspection targets in which at least one of the lead frame type, adhesive type, and roughening plating method is different from each other. The image inspection system according to claim 3.

5. The optical system is configured to function as coaxial incident illumination when the lead frame is not subjected to roughening plating. The image inspection system according to claim 4.

6. The determination unit is configured to detect the shape of the adhesive based on the brightness difference in the imaging data. The image inspection system according to claim 2.

7. Light having a wavelength spectrum corresponding to the aforementioned lighting conditions is dimmed using a set of white, red, green, and blue light sources. The image inspection system according to claim 1.

8. The illumination conditions include irradiating with light of a first wavelength spectrum at a first angle while irradiating with light of a second wavelength spectrum at a second angle. The image inspection system according to claim 1.

Images