Patent ID: 12236570

DETAILED DESCRIPTION

Embodiments provide an appearance inspection system and an appearance inspection method capable of detecting defective thermocompression bonding of taping packaging.

In general, according to one embodiment, an inspection system includes an infrared imaging device for acquiring an image of a thermocompression-bonded tape package with infrared light. The tape package has a first tape covering a second tape, which has a pocket for an electronic component. A controller is provided. The controller is configured to receive the image of the thermocompression-bonded tape package and detect a state of thermocompression bonding in a predetermined region of the tape package based on the received image.

Hereinafter, an appearance inspection system and an appearance inspection method according to certain example embodiment of the present disclosure will be described with reference to the drawings. Embodiments illustrated below are non-limiting examples, and the present disclosure is not limited to these example embodiments. In the drawings, the components, elements, or aspects which are the same or have substantially similar functions may be designated by the same reference symbols, and descriptions of repeated components, elements, or aspects may be omitted from the description of subsequently described drawings and/or embodiments. Furthermore, the drawings are conceptual and/or schematic, thus for the sake of convenience of description, the depicted dimensions, scales, dimensional ratios of different components, elements or aspects may differ drawing to drawing and from an actual embodiment. Likewise, parts of a configuration may be omitted from a drawing to provide representational clarity with respect to the particular aspects being described.

One Example Embodiment

FIG.1illustrates a configuration example of an appearance inspection system1according to an embodiment. The appearance inspection system1can detect a defect in thermocompression bonding of taping packaging (tape packaging) by inspection using infrared light or the like.

That is, the appearance inspection system1includes an appearance inspection device100, a control device200, and a display device300. The appearance inspection device100can thermocompression-bond a cover tape3to an embossed tape2and can also perform infrared imaging of the thermocompression-bonded embossed tape2. The embossed tape2may be referred to as a second tape, and the cover tape3may be referred to as a first tape. The thermocompression bonding of the cover tape3to the embossed tape2is referred to as taping packaging.

The embossed tape2will be described with reference toFIGS.2A to2C.FIG.2Ais a view of the thermocompression-bonded embossed tape2wound on a take-up reel7.FIG.2Bis a plan view of the thermocompression-bonded embossed tape2.FIG.2Cis a cross-sectional view taken along line A-A ofFIG.2B.

As illustrated inFIGS.2A to2C, in the embossed tape2, pockets5for accommodating electronic components4are continuously formed along the X direction (tape feeding direction) at regular intervals. The pockets5initially have an open upper surface to permit electronic components4to be placed inside the pockets5. The embossed tape2is made of a material with a higher absorption of infrared light than the cover tape3. The embossed tape2is made of, for example, a black material with a high absorbance of infrared light.

More specifically, the embossed tape2constitutes, for example, a carbon fiber reinforced plastic or a general-purpose plastic resin. The plastic resin is, for example, polystyrene resin (PS) such as general-purpose polystyrene resin (GPPS) or impact-resistant polystyrene resin (HIPS) to which rubber is added, polyethylencaterephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), acrylic resin (PMMA), acrylonitrile butadiene styrene (ABS), or the like. Then, guide holes6are continuously formed at one edge of the embossed tape2at regular intervals.

The cover tape3is, for example, a transparent or semi-transparent tape. The cover tape3is made of vinyl, polyethylene terephthalate (PET), polystyrene resin (PS), or the like. In this context, the term “transparent” or “semi-transparent”means that an interaction with infrared light is lower than for the embossed tape2, such that what is on a lower surface side of the cover tape3can be seen by infrared light passing through the cover tape3. The embossed tape2has a higher light absorption of infrared light than the cover tape3, and is composed of a colored material or a material through which infrared light does not transmit substantially.

A width (a length in the Y direction) of the cover tape3is smaller than a width of the embossed tape2so as not to cover the guide holes6. Therefore, when the cover tape3is properly overlapped on the embossed tape2so as to cover upper surface openings of the pockets5of the embossed tape2in which the electronic components4are accommodated, the cover tape3does not close (block) the guide holes6. The electronic component4is a semiconductor device such as an integrated circuit (IC) chip or the like. As described above, the electronic component4being accommodated in the embossed tape2and then the cover tape3being overlapped on the embossed tape2and thermocompression-bonded is sometimes referred to as taping packaging or tape packaging. The present embodiment is not limited to accommodating just an electronic component4in the pocket5. In other examples, something other than an electronic component4may be accommodated in a pocket5either instead of or along with an electronic component4.

Referring back toFIG.1, the appearance inspection device100includes reels7and11, a sprocket8, a roll12, a rotary pulley13, a thermocompression bonding device15, an infrared imaging device20, and an infrared light source22.

The control device200controls the entirety of the appearance inspection system1. That is, the control device200can control the appearance inspection device100and can determine a state of thermocompression bonding of the embossed tape2. Details of the control device200will be described below. Thermocompression bonding may also be referred to as heat welding.

The display device300is, for example, a monitor. The display device300can display an infrared image of the embossed tape2, and a determination of pass/failure of the embossed tape2.

An input device400is composed of, for example, a keyboard, a mouse, and the like. The input device400can be used to set a feed pitch of the embossed tape2or the like.

The reel7includes, for example, a drive motor. Thereby, the reel7(wind-up reel) can wind thereon the embossed tape2to which the cover tape3has been thermocompression-bonded in synchronization with the rotation of sprocket8under the control of the control device200.

The sprocket8includes tooth tips that engage with the guide holes6. Then, the sprocket8rotates under the control of the control device200. Thereby, the embossed tape2is intermittently fed at a predetermined pitch by rotational drive of the sprocket8.

The embossed tape2is initial wound on the reel11(feed reel). The cover tape3is initially wound on the roll12(cover tape feed reel).

The thermocompression bonding device15operates under the control of the control device200and includes a pedestal15aand a welding head15b.FIG.3is a view illustrating a configuration example of the welding head15bof the thermocompression bonding device15.

As illustrated inFIG.3, the welding head15bincludes a heating unit150band a thermocompression bonding head152b. The heating unit150bincludes a built-in heater154b. The thermocompression bonding head152bincludes a pair of leg portions156bprojecting from a lower surface and extending in a band shape along the X direction (a tape feeding direction). The lower surfaces of the leg portions156bare heated to, for example, 160 degrees by the heating unit150band thus function as a pair of welding surfaces.

FIG.4is a plan view illustrating a state in which the cover tape3is overlapped on the embossed tape2. Regions78aand80aare welding regions where the pair of welding surfaces of the leg portions156bcontact the cover tape3. That is, the regions78aand80aare regions where the cover tape3is overlapped on the embossed tape2. Each time the regions78aand80aare intermittently fed to the region A5directly below the welding head15b, the welding head15bdescends toward the pedestal15a, and the pair of welding surfaces of the leg portions156bthermocompression-bond the regions78aand80a.

A length of intermittent feeding is, for example, about 1 to ⅓ of a length of the welding surface of the thermocompression bonding device15in the X direction. Thereby, thermocompression bonding is performed, for example, 1 to 3 times on the regions78aand80awhere the embossed tape2and the cover tape3having the same length as the pair of welding surfaces of the leg portion156boverlap each other.

FIG.5is a plan view illustrating the cover tape3thermocompression-bonded to the embossed tape2. Left and right regions78band80bof the cover tape3are thermocompression-bonded regions. In the regions78band80b, materials of the embossed tape2and the cover tape3have been heat-welded to be integrated (joined or fused together). A region A10indicates an imaging range of the infrared imaging device20.

Referring back toFIG.1, the infrared imaging device20operates under the control of the control device200, and is composed of, for example, a Bayer-arranged CCD including R (red), G (green), and B (blue) pixels. A color filter of each of the R, G, and B pixels transmits light in an infrared region therethrough.

FIG.6is a diagram illustrating sensitivity characteristics of the infrared imaging device20. A vertical axis indicates sensitivity (arbitrary unit) of the R, G, and B pixels, and a horizontal axis indicates a wavelength detected. As illustrated inFIG.6, the infrared imaging device20has, for example, a wavelength of 850 nanometers in an infrared region and has sensitivity in a wavelength range of 750 to 900 nanometers. As described above, it is desirable that a wavelength range of infrared light at which the infrared imaging device20exhibits effective sensitivity includes 750 to 900 nanometers.

Referring back toFIG.1, the infrared light source22operates under the control of the control device200.FIG.7is a diagram illustrating wavelength characteristics of the infrared light source22. A vertical axis illustrates light emission intensity (arbitrary unit), and a horizontal axis illustrates a wavelength. As illustrated inFIG.7, light emission intensity of the infrared light source22has a peak at 850 nanometers in an infrared region.

Referring back toFIG.1, the infrared imaging device20captures an image in the region A10illuminated by the infrared light source22under the control of the control device200whenever the thermocompression-bonded embossed tape2and the cover tape3are fed to the region A10(seeFIG.5). The infrared imaging device20stores the captured image in a memory unit202of the control device200.

FIG.8is a block diagram illustrating a configuration of the control device200. The control device200can be, for example, a microcontroller including a central processing unit (CPU), a memory unit202, and the like. The control device200performs control according to a program stored in the memory unit202. That is, the control device200is configured with a rotation control unit204, an imaging control unit206, a compression bonding control unit208, a determination unit210, and a display control unit212according to the execution of the program stored in the memory unit202. In other examples, the rotation control unit204, the imaging control unit206, the compression bonding control unit208, the determination unit210, and/or the display control unit212may be configured as an electronic circuit or a separate processing unit.

A memory unit202and stores various types of information for the appearance inspection system1. The memory unit202stores information of, for example, a rotation speed and a rotation position of the reel7, a rotation speed and a rotation position of the sprocket8, a vertical position of the thermocompression bonding device15, image data from the infrared imaging device20, and the like.

The rotation control unit204performs control to rotate the reel7and the sprocket8in synchronization with each other according to a feed pitch of the embossed tape2set by the input device400. Further, positions of the regions78band80binfrared-imaged in the region A10(seeFIG.5) based on the rotation information of the reel7and the sprocket8are stored in the memory unit202in association with positions of the guide holes6. Further, the rotation control unit204according to the present embodiment assigns numbers from the first guide hole6to the last guide hole6of the embossed tape2and tracks the position of the embossed tape2based on the assigned numbers.

The imaging control unit206controls the infrared imaging device20to image the regions78band80bin the region A10(seeFIG.5) in synchronization with intermittent feeding of the embossed tape2. The imaging control unit206also controls light emission of the infrared light source22. The imaging control unit206stores the image data captured by the infrared imaging device20in the memory unit202in association with the positions (numbers) of the guide holes6of the embossed tape2according to information of the rotation control unit204.

The compression bonding control unit208controls a vertical movement of the welding head15bof the thermocompression bonding device15in synchronization with the intermittent feeding of the embossed tape2.

The determination unit210detects the states of the regions78band80b(seeFIG.5) by using an infrared image captured by the infrared imaging device20. Further, the determination unit210also inspects a position, an appearance, and the like of the electronic component4in the pocket5by using the infrared image captured by the infrared imaging device20and detects a position state of the electronic component4inside the pocket5.

The display control unit212causes the display device300to display a determination result from the determination unit210together with the infrared image captured by the infrared imaging device20. For example, the display control unit212causes the display device300to display the infrared image and determination information when an abnormality is detected by the determination unit210.

FIG.9is a view illustrating an example of an infrared pickup image in the region A10(seeFIG.5) when the detected state is “good”. A cross-section image190is a view schematically illustrating what a cross-section corresponding to the analysis image at a cross section line B-B would be expected to look like. When the regions78band80bare in a good state of thermocompression bonding, an upper surface of the embossed tape2and a lower surface of the cover tape3are fused to form an integrated fusion region f7a. When performing infrared imaging, the fusion region f7ais imaged as black (appears black). That is, an absorption of the fusion region f7awith respect to infrared light emitted from the infrared light source22is higher than the other regions.

Regions76aand76bindicate determination regions of lead positions of the electronic component4. Regions76cand76dindicate determination regions of a main body portion of the electronic component4. In the example ofFIG.9, head regions at both ends of a lead are appropriately placed in the regions76aand76b. Further, the example ofFIG.9is an example in which diagonally positioned regions of a main body (e.g., opposite corners) are appropriately placed in the regions76cand76d.

In broadband visible imaging, visible light does not substantially penetrate the cover tape3, and it is difficult to perform an internal inspection of the electronic component4in the pocket in a state where the cover tape3is already overlapped on the embossed tape2. In contrast to this, the appearance inspection device100includes the infrared imaging device20, and thus, the inside of the pocket5can be imaged even with the cover tape3already overlapped on the embossed tape2. Thereby, the appearance inspection device100can perform an internal inspection with the cover tape3overlapped on the embossed tape2.

FIG.10is a view illustrating an example of an infrared pickup image in the region A10(seeFIG.5) when a determination state is “not good”. A cross section image192is a view schematically what a cross-section corresponding to the analysis image at a cross section line C-C would be expected to look like. When thermocompression bonding states of regions78band80bare not good, fusion regions f7band f7cin which an upper surface of the embossed tape2and a lower surface of the cover tape3are fused and integrated are formed in only parts of the regions78band80b. In other words, when the thermocompression bonding states of the regions78band80bare not good, the upper surface of the embossed tape2and the lower surface of the cover tape3have regions that are not fused together and not integrated. When performing infrared imaging, the fusion regions f7band f7cappear as black regions. Regions where the fusion regions f7band f7care not formed appear as white regions f7dand f7e.

That is, absorption of the fusion regions f7band f7cwith respect to infrared light emitted from the infrared light source22is higher than absorption of the other regions. Where the fusion regions f7band f7care not formed, the absorption of infrared light is lower than the fusion regions f7band f7c. Reflectance of infrared light from the regions where the fusion regions f7band f7care not formed can be higher than the infrared reflectance of the fusion regions f7band f7c.

In the example ofFIG.10, the electronic component4is also tilted (askew). Therefore, head regions at both ends of a lead are not appropriately placed inside the regions76aand76b. Likewise, diagonal regions of a main body are not appropriately placed inside the regions76cand76d.

FIG.11is a view schematically illustrating a blackening phenomenon. As illustrated inFIG.11, infrared light L11and L13incident on the fusion regions f7band f7care absorbed into the fusion regions f7band f7cand reflection thereof is prevented. The infrared light L12incident outside the fusion regions f7band f7cis reflected from an upper surface of the embossed tape2or an upper surface of the electronic component4and is imaged. Details of such a phenomenon are being analyzed, but it is considered that a black color of the embossed tape2is fused with the cover tape3and a black region approaches an upper surface side of the cover tape3to increase an absorption of infrared light and reduce the reflected light.

FIG.12is a block diagram illustrating a configuration example of the determination unit210. As illustrated inFIG.12, the determination unit210includes a binarization processing unit210a, a labeling processing unit210b, an outer shape extraction processing unit210c, and a determination processing unit210d.

The binarization processing unit210aextracts images corresponding to the regions78band80bfrom the images in the region A10(seeFIG.5). Then, the binarization processing unit210abinarizes the image extracted experimentally according to a predetermined threshold value.

The labeling processing unit210blabels black regions corresponding to the fusion regions f7a, f7b, and f7c(seeFIGS.9and10) from the image region binarized by the binarization processing unit210a. Then, the labeling processing unit210bcounts the number of pixels in the labeled black regions.

The outer shape extraction processing unit210cextracts a circumscribed contour line of the image region inside compression bonding regions78band80b. Such a circumscribed contour line can be processed by general image processing.

The determination processing unit210ddetermines compression bonding states of the regions78band80bbased on the number of pixels counted by the labeling processing unit210b. The determination processing unit210ddetermines, for example, that thermocompression bonding of the predetermined regions78band80bis in a failed state (“not good”) when a ratio of black regions occupying the predetermined regions78band80bis less than or equal to some predetermined value. More specifically, the determination processing unit210ddetermines that compression bonding is in a good state when the number of pixels counted by the labeling processing unit210bis greater than a first threshold value. If the number of counted pixels is smaller than a second threshold value, which is a value smaller than the first threshold value, the determination processing unit210ddetermines that compression bonding is in a failed state. Setting of a threshold value is not particularly limited, and, for example, the first threshold value and the second threshold value may be set to the same value, or additional threshold values may be set according to additional states to be detected or the like. By increasing the number of threshold values, determination of the compression bonding state can be further subdivided beyond a good/bad determination.

Further, the determination processing unit210ddetermines that a position of the electronic component4is in a good state when right-angled contour lines along a predetermined direction are respectively placed in the regions76a,76b,76c, and76d, based on the circumscribed contour lines extracted by the outer shape extraction processing unit210c. The determination processing unit210ddetermines that the position of the electronic component4is in a failed state when the right-angled contour lines in a predetermined direction are not respectively placed in the regions76a,76b,76c, and76d.

The above description is made for a configuration of the appearance inspection system1. A control example of the control device200will be described below with reference toFIGS.13to15.FIG.13is a flowchart illustrating a control example of the control device200.FIG.14is a view illustrating an example of a display image of the display device300when the determination unit210determines to be abnormal.FIG.15is a flowchart illustrating a detailed processing example of step S30ofFIG.13.

As illustrated inFIG.13, the rotation control unit204of the control device200rotates the reel7and the sprocket8in synchronization with each other according to a feed pitch of the embossed tape2. Thereby, when the embossed tape2and the cover tape3are intermittently fed and are located in the lower region A5(seeFIG.4) of the welding head15b, the tape feeding is interrupted. Then, a pair of welding surfaces of the leg portions156bheated to a constant temperature, for example, 160 degrees, are moved by the heating unit150bto press and weld an overlapped portion overlapped with the embossed tape2in the left and right regions78aand80aof the cover tape3. That is, the welding surfaces are thermocompression-bonded, and an upper surface opening of the pocket5of the embossed tape2is sealed with the cover tape3(step S10). In this way, the electronic component4is taping packaging by sealing the upper surface opening of the pocket5of the embossed tape2with the cover tape3.

After pressing and welding, when the welding head15bascends to be separated from the cover tape3, the embossed tape2is fed from the reel11under the welding head15bby driving of the sprocket8, and the cover tape3is fed from the roll12by folding back the rotary pulley13. Thereby, the cover tape3is put on the embossed tape2, and the welding head in a heated state descends again to press and weld the embossed tape2and the cover tape3. That is, the welding surfaces thermocompression-bond the embossed tape2and the cover tape3. Ascending and descending of the welding head15band feeding of the embossed tape2and the cover tape3are repeated, and thereby, the thermocompression-bonded embossed tape2and the cover tape3are sequentially wound on to the reel7.

The imaging control unit206causes the infrared light source22to emit light and the infrared imaging device20to image the embossed tape2fed to the imaging region A10after the intermittent feeding of the embossed tape2and the cover tape3is repeated. Then, the imaging control unit206stores the captured infrared image in the memory unit202in association with positions of the guide holes6(step S20).

The determination unit210determines states of the thermocompression-bonded regions78band80b(seeFIG.5) by using the infrared image captured by the infrared imaging device20. Further, the determination unit210detects a position state of the electronic component4by using the infrared image (step S30). Then, the display control unit212causes the display device300to display the infrared image and determination information (seeFIG.14) when the determination unit210detects an abnormality.

As illustrated inFIG.14, an infrared image M12(determined to be abnormal) and the determination information M14are displayed in a display image M10of the display device300. The determination information M14displays the location information for the guide holes6and a reason for abnormality (abnormality type).

A more detailed processing example of step S30will be described with reference toFIG.15. Initially, the binarization processing unit210aextracts images of the compression bonding regions78band80bfrom the infrared image and binarizes the images (step S100).

Next, the labeling processing unit210blabels black portion regions as binarized by the binarization processing unit210a. Then, the labeling processing unit210bcounts the number of pixels in the labeled black portion regions (step S102).

Next, the outer shape extraction processing unit210cextracts circumscribed contour lines of image regions inside the compression bonding regions78band80b(step S104).

Then, the determination processing unit210ddetermines whether the processing appears normal (step S106). That is, when the number of pixels counted by the labeling processing unit210bis greater than a first threshold value, the determination processing unit210ddetermines that thermocompression bonding is in a good state (normal), and when right-angled contour lines in a predetermined direction are placed in the regions76a,76b,76c, and76d, the determination processing unit210ddetermines that a position of the electronic component4is in a good state (normal) (Y in step S106). Then, the determination processing unit210dends the determination processing.

If the number of counted pixels is smaller than a second threshold value, the determination processing unit210ddetermines that the compression bonding is in a failed state, and when the right-angled contour lines in a predetermined direction are not respectively placed in the regions76a,76b,76c, and76d, the determination processing unit210ddetermines that a position of the electronic component4is in a failed state. When the thermocompression bonding is in a failed state or the position of the electronic component4is in a failed state, the determination processing unit210ddetermines that processing is not normal (N in step S106).

Further, the determination processing unit210dstores the position information of the guide holes6and a reason for abnormality in the memory unit202in association with each other (step S108). Then, the display control unit212causes the infrared image M12that has been determined to be abnormal and the corresponding determination information M14(seeFIG.14) to be displayed in the display image M10of the display device300(step S110). Then, the determination processing unit210dends the determination processing.

As described above, according to the present embodiment, the infrared imaging device20images, with infrared light, the predetermined regions78band80bin the embossed tape2in which the electronic component4can be inserted and the overlapped cover tape3is thermocompression-bonded in the predetermined regions78band80b, and the determination unit210determines a state of thermocompression bonding of the predetermined regions78band80bby using the infrared image captured by the infrared imaging device20by including at least a part of the predetermined regions78band80b. Thereby, it is possible to determine a state of thermocompression bonding of the predetermined regions78band80bbased on information of the predetermined regions78band80bin an infrared image.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.