JP2021141270A5 - - Google Patents

Description

FIG. 1(a) is a perspective view showing a normal-field optical system, and FIG. 1(b) is a perspective view showing a wide-field optical system. FIG. 2(a) is a conceptual diagram of a wide-field optical system using a macro lens, and FIG. 2(b) is a conceptual diagram of a wide-field optical system using a telecentric lens. FIG. 3(a) is a diagram showing an image of the three-dimensional shape of the paste, and FIG. 3(b) is a diagram showing bright lines on the paste when the substrate is viewed in a wide area through a macro lens. FIG. 4(a) is a top view for explaining the multiple arrangement of the imaging device of the embodiment, and FIG. 4(b) is a side view when viewed from the direction of arrow A in FIG. 4(a). FIG. 5 is a diagram illustrating a lighting device used in the imaging device of the embodiment. FIG. 6 is a top view illustrating overlap of imaging fields of a plurality of imaging devices. 7 is a side view when viewed from the direction of arrow A in FIG. 6. FIG. FIG. 8 is a diagram for explaining the overlapping amount of imaging fields of view. FIG. 9 is a diagram for explaining image mosaicing and coordinate mapping. FIG. 10 is a schematic diagram for explaining image mosaicing and coordinate transformation using a calibration plate. FIG. 11 is a diagram for explaining distortion. FIG. 12 is a diagram showing transformation matrix equations for affine transformation and projective transformation. FIG. 13 is a diagram for explaining image mosaicing and coordinate transformation using a substrate target model. FIG. 14 is a diagram for explaining the influence of temporal displacement of the imaging device. FIG. 15 is a diagram for explaining spatial re-correction. FIG. 16 is a diagram explaining a method of changing the height of the calibration plate. FIG. 17 is a diagram for explaining markers provided on the chute. FIG. 18 is a perspective view for explaining multiple imaging devices in a modified example. FIG. 19 is a top view showing the outline of the die bonder in the embodiment. 20A and 20B are diagrams for explaining the operation of the pickup head and the bonding head when viewed from the direction of arrow A in FIG. 21 is a schematic cross-sectional view showing the main part of the die supply section of FIG. 19. FIG. 22 is a block diagram showing a schematic configuration of the control system of the die bonder of FIG. 19. FIG. FIG. 23 is a flow chart showing a method of manufacturing a semiconductor device.

Synthesis of a plurality of captured images will be described with reference to FIGS. 9 to 15. FIG. FIG. 9 is a diagram for explaining image mosaicing and coordinate mapping. FIG. 10 is a schematic diagram for explaining image mosaicing and coordinate transformation using a calibration plate. FIG. 11 is a diagram for explaining distortion. FIG. 12 is a diagram showing transformation matrix equations for affine transformation and projective transformation. FIG. 13 is a diagram for explaining image mosaicing and coordinate transformation using a substrate target model. FIG. 14 shows images of a state in which a paste adhesive is applied to tabs of a multiple lead frame, taken by a plurality of imaging devices, and FIG. (b) is a captured image when there is a time-lapse variation. 15A and 15B are diagrams for explaining spatial re-correction, FIG. 15A is a diagram showing a state before spatial re-correction, and FIG. 15B is a diagram showing a state after spatial re-correction.

The above (A) will be described with reference to FIGS. 9 to 12. FIG.
As shown in FIG. 9, the control unit CNT projects a coordinate marker CMRK, which is a scale covering all the imaging fields of the multiple imaging devices during adjustment of the die bonding apparatus, and a coordinate marker that falls within the range of the overlapping area OVL. A single image (composite image) is obtained by smoothly connecting the images of the imaging devices by subjecting the image to coordinate transformation such as projective transformation or affine transformation based on the same intersection point IP of the CMRK. Here, the coordinate marker CMRK is used by marking a calibration plate prepared as an adjustment jig and marking the plate, and the coordinate marker CMRK is, for example, a grid shape. During coordinate transformation, markers are required to guarantee the positional relationship of the entire space. If there is a coordinate marker CMRK that covers the entire synthetic field of view as shown in FIG. 9, the positional relationship in the entire space can be guaranteed during coordinate transformation such as projective transformation. Coordinate matching is possible.

First, the control unit CNT transforms the pixel coordinates of the image of the other imaging device based on one of the adjacent imaging devices by affine transformation or projective transformation. Here, as an example, the reference image is the image IV1, and the conversion image is the image IV2. Transformation calculates each parameter of a transformation matrix of affine transformation or projective transformation so that the coordinates (black point coordinates) of the intersection point IP in the images to be transformed match the coordinates (black point coordinates) of the intersection point IP in the corresponding reference image. Here, in general, the transformation matrix of affine transformation is shown in equation (1) of FIG. 12, and the determinant of projective transformation is shown in equation (2) of FIG. In general, it is sufficient to have the coordinates of three points to calculate the transformation matrix. It is preferable to convert to

Coordinates are aligned in the pixel coordinate system, so the coordinates of image IV2 after transformation are required to be integer values. , the converted coordinates may be intermediate values. In such a case, each coordinate of the image after conversion is subjected to gray value interpolation represented by the nearest neighbor method, bilinear method, bicubic method, etc. from the gray value of the adjacent coordinates after conversion.

When this displacement is detected, the control unit CNT recalculates the projective transformation matrix and the affine transformation matrix for synthesizing and transforming the image using the characteristic marker such as the positioning target mark TM on the substrate S. FIG. At this time, the obtained projective transformation matrix and affine transformation matrix can connect images, but as shown in FIG. 15(a), the image space and real space may not be matched. Therefore, the control unit CNT uses the marker SMRK on the chute SCT that was measured first, and performs retransformation based on the coordinates. As a result, a synthesized image as shown in FIG. 15(b) is obtained.

In order to deal with height displacement, the control unit CNT finely moves the calibration plate CP up and down to obtain a projective transformation matrix for each height. The control unit CNT calculates the expected height of the alignment pattern position and inspection field position from known substrate thickness, paste height, die thickness, etc., and automatically selects which projection transformation matrix to use for each height. do. The control unit CNT recognizes the same point on the substrate in the overlapping area between adjacent imaging devices and measures the height. The control unit CNT automatically selects the projective transformation matrix to be used from the measured values.

Claims (23)

a transport path for transporting the substrate;
a plurality of imaging devices fixedly arranged in a row above the transport path along the width direction of the substrate;
A plurality of attachment regions arranged in a row along the width direction and positioned on the substrate are imaged by the plurality of imaging devices to obtain a plurality of images, and a composite image is generated based on the plurality of the obtained images. a controller configured to recognize an imaging target in the attachment area based on the composite image;
with
The die bonding apparatus according to claim 1, wherein imaging fields of view of respective imaging devices overlap on the substrate, and the overlapping imaging fields of view are larger than the attachment area. The die bonding apparatus of claim 1,
The die bonding apparatus, wherein the controller is configured to generate the composite image based on coordinate markers located in the overlapping imaging fields. In the die bonding apparatus of claim 2,
the coordinate marker is a grid-like scale covering the field of view of all the imaging devices;
The control unit displays the coordinate markers, performs projective transformation on the image with reference to the same intersection of the coordinate markers in the overlapping imaging fields, and joins the images of the imaging devices to generate the composite image. A die bonding apparatus configured as follows. In the die bonding apparatus of claim 3,
the transport path has a plurality of reference markers outside both ends in the width direction of the substrate,
The substrate has a plurality of tabs arranged at predetermined intervals,
The die bonding apparatus, wherein the controller is configured to measure the interval between the tabs or the interval between the reference markers with the imaging device and detect the displacement between the imaging devices. In the die bonding apparatus of claim 4,
the substrate further comprises a characteristic marker;
The die bonding device, wherein the control unit is configured to recalculate a projective transformation matrix for synthesizing an image based on the characteristic marker when a displacement between the imaging devices is detected. In the die bonding apparatus of claim 5,
The control unit is configured to recalculate the projective transformation matrix based on the coordinates of the previously measured reference marker. In the die bonding apparatus of claim 6,
The control unit finely moves the substrate up and down to obtain a projective transformation matrix for each height,
Calculate the expected height of the alignment pattern position or the inspection field position from the thickness of the substrate, the paste height, or the die thickness, and based on the calculated expected height, any of the projection transformation matrices held for each height A die bonding apparatus configured to select between: In the die bonding apparatus of claim 7,
The control unit recognizes the same point on the substrate in an overlapping field of view between adjacent imaging devices, measures the height, and maintains each height based on the measured height. die bonding apparatus configured to select the projective transformation matrix. In the die bonding apparatus according to any one of claims 1 to 8,
Furthermore, comprising a plurality of lighting devices provided corresponding to each of the plurality of imaging devices,
The die bonding apparatus, wherein the controller is configured to independently dim the plurality of lighting devices. In the die bonding apparatus according to any one of claims 1 to 8,
The control unit is a die bonding apparatus configured to convey the substrate in the length direction of the substrate and image the plurality of attachment regions in the next row with the plurality of imaging devices. In the die bonding apparatus according to any one of claims 1 to 8,
A die bonding apparatus, wherein the object to be imaged is a paste adhesive applied to the substrate. The die bonding apparatus of claim 11, wherein
The die bonding apparatus, wherein the control unit is configured to perform a visual inspection of the paste adhesive applied to the substrate by the imaging device. In the die bonding apparatus according to any one of claims 1 to 8,
A die bonding apparatus, wherein the imaging object is a die bonded on the substrate or an already bonded die. Corresponding to each of a transport path for transporting a substrate having a plurality of attachment areas, a plurality of imaging devices fixedly arranged in a row above the transport path along the width direction of the substrate, and the plurality of imaging devices and a plurality of lighting devices provided as a die bonding device, wherein the imaging field of view of each imaging device overlaps on the substrate, and the overlapping imaging field of view is larger than the attachment area. a step of loading the substrate;
A row of the attachment regions located on the substrate along the width direction is imaged by the plurality of imaging devices to obtain a plurality of images, and a composite image is generated based on the obtained plurality of images. and recognizing an object to be imaged in the attachment area based on the synthesized image;
a step of conveying the substrate in the length direction of the substrate and imaging a plurality of attachment regions in the next row with the plurality of imaging devices;
A method of manufacturing a semiconductor device comprising: In the method of manufacturing a semiconductor device according to claim 14,
A method of manufacturing a semiconductor device, wherein the synthesized image is generated based on the coordinate markers located in the overlapping imaging fields. In the method of manufacturing a semiconductor device according to claim 15,
the coordinate marker is a grid-like scale covering the field of view of all the imaging devices;
A method of manufacturing a semiconductor device, in which the coordinate markers are projected, an image is projectively transformed with reference to the same intersection of the coordinate markers entering the overlapping imaging fields, and the images of the imaging devices are joined to generate the composite image. . In the method of manufacturing a semiconductor device according to claim 16,
the transport path has a plurality of reference markers outside both ends in the width direction of the substrate,
The substrate has a plurality of tabs arranged at predetermined intervals,
A method of manufacturing a semiconductor device, wherein the distance between the tabs or the distance between the reference markers is measured by the imaging device, and the displacement between the imaging devices is detected. In the method of manufacturing a semiconductor device according to claim 17,
the substrate further comprises a characteristic marker;
A method of manufacturing a semiconductor device, wherein when a displacement between the imaging devices is detected, a projective transformation matrix for synthesizing and transforming an image is recalculated based on the characteristic marker. In the method of manufacturing a semiconductor device according to claim 18,
A method of manufacturing a semiconductor device, wherein the projective transformation matrix is recalculated based on the coordinates of the previously measured reference marker. In the method of manufacturing a semiconductor device according to claim 19,
Finely move the substrate up and down to obtain a projective transformation matrix for each height,
Calculate the expected height of the alignment pattern position or the inspection field position from the thickness of the substrate, the paste height, or the die thickness, and based on the calculated expected height, any of the projection transformation matrices held for each height A manufacturing method of a semiconductor device to select. In the method of manufacturing a semiconductor device according to claim 20,
recognizing the same point on the substrate in an overlapping field of view between adjacent imaging devices, measuring the height, and maintaining the projective transformation matrix for each height based on the measured height; A method of manufacturing a semiconductor device that selects In the method for manufacturing a semiconductor device according to any one of claims 14 to 21,
Furthermore, it comprises a step of applying a paste adhesive to the substrate,
A method of manufacturing a semiconductor device, wherein the object to be imaged is the applied paste adhesive. In the method for manufacturing a semiconductor device according to any one of claims 14 to 21,
further comprising bonding a die onto the substrate or an already bonded die;
A method of manufacturing a semiconductor device, wherein the object to be imaged is the bonded die.