Abstract:
An inspection method is provided herein. The inspection method is adapted for an inspection device. The inspection method includes: optically scanning an examining target for generating a scanned image; reconstructing the scanned image for a reconstructed volume; adjusting a slicing direction associated with the examining target for slicing the reconstructed volume into a sliced image; inspecting the sliced image for analyzing one or more features of the examining target; and outputting an inspection result of the examining target.

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 62/195,314, filed Jul. 22, 2015, which is herein incorporated by reference. 
    
    
     BACKGROUND 
     Field of Invention 
     The present invention relates to inspection technique. More particularly, the present invention relates to method and device for inspection. 
     Description of Related Art 
     Conventional inline 3D AXI (Advanced eXtensible Interface) equipments usually use horizontally sliced images in the inspection algorithm. A scanned image of examining target may be captured for inspection. 
     In operation, if the examining target has no significant feature in the horizontal slice, it could lead to poor efficiency of inspection algorithm, and therefore the inspection result may be difficult to be reviewed in a repair station. 
     SUMMARY 
     In one aspect, the present disclosure is related to an inspection method including the following steps: optically scanning an examining target for generating a scanned image; reconstructing the scanned image for a reconstructed volume; adjusting a slicing direction associated with the examining target for slicing the reconstructed volume into a sliced image, wherein the slicing direction comprises a non-horizontal slicing direction; inspecting the sliced image for analyzing one or more features of the examining target; and outputting an inspection result of the examining target. 
     In another aspect, the present disclosure is related to an inspection device. The inspection device includes a scanning device and a computing device. The scanning device is configured to optically scan an examining target for generating a scanned image. The computing device is connected with the scanning device and comprises a processing unit and a storage unit. The processing unit is configured to execute the following instructions: reconstructing the scanned image for a reconstructed volume; adjusting a slicing direction associated with the examining target for slicing the reconstructed volume into a sliced image, wherein the slicing direction comprises a non-horizontal slicing direction; inspecting the sliced image for analyzing one or more features of the examining target; and outputting an inspection result of the examining target to an output device in which the storage unit is configured to store the scanned image, the reconstructed volume and the sliced image. 
     By applying the techniques disclosed in the present disclosure, a non-horizontal slice of an examining target can provide some characteristics and significant features of the examining target. Therefore, the inspection performance may be improved and the inspection result may be more easily reviewed in repair station. 
     These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
         FIG. 1  is a schematic diagram illustrating an inspection device according to one embodiment of the present disclosure; 
         FIG. 2A  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure; 
         FIG. 2B  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure; 
         FIG. 3  is a schematic diagram illustrating sliced images according to one embodiment of the present disclosure; 
         FIG. 4A  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure; 
         FIG. 4B  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure; 
         FIG. 5  is a schematic diagram illustrating a reconstructed volume and corresponding sliced images according to one embodiment of the present disclosure; 
         FIG. 6  is a schematic diagram illustrating a reconstructed volume and corresponding sliced images according to one embodiment of the present disclosure; and 
         FIG. 7  is a flow chart of an inspection method according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
       FIG. 1  is a schematic diagram illustrating an inspection device  100  according to one embodiment of the present disclosure. The inspection device  100  comprises a scanning device  120 , a computing device  140 , an input device  160  and an output device  180 . The scanning device  120  further includes an X-ray generator  122 , a substrate holding unit  124  and an X-ray detector  126 . The computing device  140  comprises a processing unit  142  and a storage unit  144 . 
     The substrate holding unit  124  holds an examining target  128  to be inspected. The X-ray generator  122  generates X-ray. The X-ray is controlled by, for example, an X-ray source control mechanism, and irradiates the examining target  128 . The examining target  128  is moved by the substrate holding unit  124 , and is arranged between the radiation ray generator  122  and the X-ray detector  126 . 
     The X-ray detector  126  is for detecting the X-ray outputted from the X-ray generator  122  and transmitted through the examining target  128 . The X-rays passing through the examining target  128  are photographed as an image by the X-ray detector  126 . Hence, a “scanned image” of the examining target  128  is generated by the X-ray detector  126 . In some embodiments, the X-ray detector  126  may be an image intensifier tube or a FPD (flat panel detector), but not limited thereto. The scanned image is sent to the computing device  140  and stored in the storage unit  144 . 
     The computing device  140  includes the processing unit  142  and the storage unit  144 . The processing unit  142  further includes a reconstruction portion  152 , a slicing portion  154  and an inspection portion  156 . 
     In order to efficiently inspect the examining target  128 , the inspection device  100  extracts some features from the examining target  128 . The processing unit  142  controls the reconstruction portion  152  to receive the scanned image outputted from the X-ray detector  126  and generates a “reconstructed volume” including, for example, a three-dimensional shape of the examining target  128 . In some applications, the reconstructed volume is also referred as “3D image”. In some embodiments, the method of reconstructing the scanned image for the reconstructed volume comprises shift-and-add or CT (computed tomography), but not limited thereto. 
     In addition, the processing unit  142  further controls the slicing portion  154  to slice the reconstructed volume into a “sliced image”. In some embodiments, the sliced image is a horizontal, vertical or arbitrary cross-section cut out from the reconstructed volume. The slicing direction of the sliced image is determined according to characteristics of the examining target  128 , which will be described later. The processing unit  142  then controls the inspection portion  156  to inspect the sliced image for analyzing one or more features of the examining target  128  so as to output the inspection results of the examining target  128  to the output device  180 . 
     The input device  160  is capable of accepting instructions and the like from user. The output device  180  is capable of outputting inspection results, scanned image, reconstructed volume, sliced image and the like to outside of the inspection device  100 . In some embodiments, the input device  160  is a keyboard, and the output device  180  is a monitor. 
     In some embodiments, the computing device  140  is a PC (Personal Computer). The storage unit  144  is configured to store the scanned image, reconstructed volume, sliced image, inspection result and the like. The storage unit  144  merely needs to be able to store data, and is configured by a storage device such as RAM (Random Access Memory) and HDD (Hard Disc Drive), but not limited thereto. 
     In some embodiments, the inspection portion  156  inspects the symmetry of the slice image and outputs an abnormal result when the symmetry of the sliced image is under a predetermined threshold value. 
       FIG. 2A  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  220  corresponds to a solder ball with head-in-pillow (HIP) defect, and reconstructed volume  240  corresponds to a solder ball without HIP defect. In addition, sliced image  222  is the horizontal slice of the reconstructed volume  220 , and sliced image  242  is the horizontal slice of the reconstructed volume  240 . As shown in  FIG. 2A , it is hardly to distinguish HIP defect from a normal solder ball by the horizontal slices, since there is no clue in the horizontal slice. 
       FIG. 2B  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  220  corresponds to a solder ball with head-in-pillow (HIP) defect, and reconstructed volume  240  corresponds to a solder ball without HIP defect. In addition, sliced image  224  is the vertical slice of the reconstructed volume  220 , and sliced image  244  is the vertical slice of the reconstructed volume  240 . 
     Since the sliced image  224  and the sliced image  244  contain some vertical characteristics or information, so as to make HIP defect becomes more apparently. In other words, when the inspection device  100  inspects HIP defect of the examining target  128 , the processing unit  142  may control the slicing portion  154  to cut a vertical slice of the reconstructed volume so as to speed up the determination of HIP defect. 
       FIG. 3  is a schematic diagram illustrating sliced images according to one embodiment of the present disclosure. In this embodiment, sliced image  320  corresponds to a connector with insufficient insertion defect, and sliced image  340  corresponds to a normal connector. It is noteworthy that both of the sliced image  320  and the slice image  340  are vertically sliced. As shown in  FIG. 3 , press-fit pins  322 ,  342  are pressed into the PCB through-holes  324 ,  344  by applying mechanical force, and it is not easy to measure the insertion depth unless measuring the pin length in vertical slice. 
     In other words, when the inspection device  100  inspects insufficient insertion defect of the examining target  128 , the processing unit  142  may control the slicing portion  154  to cut a vertical slice of the reconstructed volume so as to speed up the determination of insufficient insertion defect. 
     In some embodiments, the inspection portion  156  may use multiple vertical slices to evaluate solder quality of package component. For example, vertical slices represent solder thickness profile, and therefore the inspection portion  156  may use the thickness profile to extract proper features, such as gradient, curvature, shape descriptor, geometric characteristics and the like. With the features of the solder, it is possible to create some inspection rules for quality determination, so as to speed up the determination of solder quality. Hence, in one embodiment, the inspection portion  156  may output the inspection result to the output device  180 , such as in sufficient solder, open defect, excessive solder, good solder or NG solder. In another embodiment, the sliced images are displayed on the output device  180  for visual determination of solder quality by examiner. 
       FIG. 4A  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  420  corresponds to a component with open defect, and reconstructed volume  440  corresponds to a component without open defect. In addition, sliced image  422  is the horizontal slice of the reconstructed volume  420 , and sliced image  442  is the horizontal slice of the reconstructed volume  440 . 
     As shown in  FIG. 4A , it is hardly to detect open defect from normal examining target by only using the horizontal slice, such as the sliced image  422  and the sliced image  442 , since there is no clue in the horizontal slice. 
       FIG. 4B  is a schematic diagram illustrating reconstructed volumes and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  420  corresponds to a component with open defect, and reconstructed volume  440  corresponds to a component without open defect. In addition, sliced image  424  is the vertical slice of the reconstructed volume  420 , and sliced image  444  is the vertical slice of the reconstructed volume  440 . 
     For example, the inspection portion  156  may inspect open defect according to the shape of profile. As shown in  FIG. 4B , if the shape is climbing from ground to the top like a hill, such as the edge of the sliced image  444 , it means that the solder connects with the component well, and the open defect does not exist. 
       FIG. 5  is a schematic diagram illustrating a reconstructed volume and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  520  corresponds to a component with non-wetting open defect. In addition, sliced images  522 A- 522 C are the horizontal slices of the reconstructed volume  520 , and sliced image  524  is the vertical slice of the reconstructed volume  520 . 
     As shown in  FIG. 5 , there is no significant feature in the horizontal slices  522 A- 522 C. Therefore, it is hard for the inspection portion  156  to determine non-wetting open defect according to the horizontal slices  522 A- 522 C. 
     However, as shown in the sliced image  524 , when non-wetting open defect occurs in the examining target  128 , there are two blobs of solder on vertical cross section. Therefore, the inspection portion  156  may detect non-wetting open defect with solder connectivity feature by using the vertical slice. In other words, when the inspection device  100  inspects non-wetting open defect of the examining target  128 , the processing unit  142  may control the slicing portion  154  to cut a vertical slice of the reconstructed volume so as to speed up the determination of non-wetting open defect. 
       FIG. 6  is a schematic diagram illustrating a reconstructed volume and corresponding sliced images according to one embodiment of the present disclosure. In this embodiment, reconstructed volume  620  corresponds to a component with short defect. As shown in  FIG. 6 , solder ball  622  and solder ball  624  are shorted by redundant solder  626 . In addition, sliced image  640  is the horizontal slice of the reconstructed volume  620 , and sliced image  660  is the vertical slice of the reconstructed volume  620 . 
     It is difficult to inspect the short defect by using horizontal slice, especially when the redundant solder  626  is not located in the same height with the solder ball  622  and the solder ball  624 . However, vertical slice may directly reflect some significant features of short defect, so as to let the inspection portion  156  detect short defect successfully. 
     In some embodiments, the inspection device  100  further includes a drive mechanism  130  to transfer the examining target  128 . Hence, the inspection portion  156  inspects the sliced image so as to detect whether the examining target  128  is abnormal in real time during the examining target  128  on drive mechanism  130 . 
     Reference is now made to  FIG. 7 .  FIG. 7  is a flow chart of an inspection method in accordance with one embodiment of the present disclosure. The inspection method may be implemented by the inspection device  100  illustrated in  FIG. 1 , but is not limited in this regard. For convenience and clarity, it is assumed that the inspection method is implemented by the inspection device  100  illustrated in  FIG. 1 . 
     In step  702 , the scanning device  120  scans the examining target  128  so as to generate the scanned image. In step  704 , the processing unit  142  controls the reconstruction portion  152  so as to reconstruct the reconstructed volume from the scanned image. In step  706 , the processing unit  142  adjusts the slicing direction of the slicing portion  154  according to features of the examining target  128 , so as to slice the reconstructed volume into the sliced image. 
     In step  708 , the inspection portion  156  inspects the sliced image according to one or more features of the examining target  128  stored in the storage unit  144 , so as to generate the inspection result of the examining target  128 . In step  710 , the computing device  140  outputs the inspection result of the examining target  128  to the output device  180 . 
     By applying the techniques disclosed in the present disclosure, a non-horizontal slice of an examining target can provide some characteristics and significant features of the examining target. Therefore, the inspection performance may be improved and the inspection result may be more easily reviewed in repair station. 
     Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.