The present invention relates to a wire shape measurement device for measuring a shape of a wire that connects an electrode of a semiconductor element mounted on a substrate and an electrode of the substrate, a method for generating a three-dimensional image of the wire, and a wire shape measurement method for measuring a wire shape.
A loop shape of a bonding wire (hereinafter referred to as wire) that connects a pad of a semiconductor chip and a lead of a substrate is measured. A method of detecting XY coordinates of the wire at a focusing height of an optical system to measure a three-dimensional shape of the entire wire has been proposed as a method for measuring the loop shape of the wire (see, for example, Patent Document 1).
This method illuminates the wire with a ring-shaped illuminator, captures wire images while changing the focusing height using the optical system with a shallow depth of focus, and detects a dark part that appears in the center of each wire image, so as to detect the XY coordinates of the wire at each focusing height and detect the three-dimensional shape of the entire wire from the data.
[Patent Document 1] Specification of Japanese Patent No. 3235009
In recent years, there has been a demand for measuring the shapes of all the wires connecting the electrode of the semiconductor chip and the electrode of the substrate. However, according to the wire shape measurement method described in Patent Document 1, it is necessary to capture a plurality of images by changing the focusing height of the optical system, and therefore the time required for the inspection is long.
Further, it is also required to improve the accuracy of wire shape measurement. When the wire is illuminated with a ring-shaped illuminator as in the conventional technology described in Patent Document 1, in the portion where the wire extends in the substantially horizontal direction in the image, the vicinity of the center line of the wire at the focal point is dark and the edges at both ends of the wire in the width direction are bright, but in the portion where the wire is inclined, the vicinity of the center line of the wire may be bright and the edges at both ends of the wire in the width direction may be dark. Therefore, in the conventional technology described in Patent Document 1, the detection accuracy of the three-dimensional shape of the entire wire may decrease for a wire having an inclined portion.
The present invention is to provide a wire shape measurement device that is capable of measuring a shape of a wire with high accuracy in a short time.
A wire shape measurement device according to the present invention is for a semiconductor device, which includes: a substrate; a semiconductor element mounted on the substrate; and a wire connecting an electrode of the semiconductor element and an electrode of the substrate, or connecting one electrode of the semiconductor element and another electrode of the semiconductor element. The wire shape measurement device includes: a plurality of cameras capturing two-dimensional images of the semiconductor device; and a control unit measuring a shape of the wire based on the two-dimensional images of the semiconductor device acquired by the cameras. The control unit: generates a three-dimensional image of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by pattern matching using connection position information of a position where the wire is connected to the substrate or the semiconductor element and thickness information of the wire, and measures the shape of the wire based on the three-dimensional image of the wire generated.
Since the three-dimensional image of the wire is generated from the two-dimensional images of the semiconductor device acquired by the cameras by pattern matching using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire, the three-dimensional image can be generated accurately in a short time. Thereby, the wire shape measurement device capable of measuring the shape of the wire with high accuracy in a short time can be provided.
In the wire shape measurement device according to the present invention, the control unit may respectively extract two-dimensional coordinates of each point in each two-dimensional image corresponding to one portion of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire, calculate three-dimensional coordinates of one portion of the wire by using the two-dimensional coordinates extracted, and generate a three-dimensional image of the wire based on the three-dimensional coordinates calculated.
Further, in the wire shape measurement device according to the present invention, the control unit may repeatedly respectively extract two-dimensional coordinates of each point in each two-dimensional image corresponding to one portion of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire from a start end to a terminal end of the wire, to extract the two-dimensional coordinates of each point in each two-dimensional image respectively corresponding to a plurality of portions of the wire, calculate three-dimensional coordinates of the plurality of portions of the wire by using the two-dimensional coordinates in each two-dimensional image respectively corresponding to the plurality of portions of the wire extracted, and generate a three-dimensional image from the start end to the terminal end of the wire based on the three-dimensional coordinates of the plurality of portions of the wire calculated.
Since the image of the wire is specified from the two-dimensional images of the entire semiconductor device captured by the cameras using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire, and the two-dimensional coordinates of the point on the wire image are extracted, the two-dimensional coordinates of the point on the image of the wire can be extracted from the two-dimensional images of the entire semiconductor device in a short time. Thereby, the wire shape measurement device capable of measuring the shape of the wire with high accuracy in a short time can be provided.
In the wire shape measurement device according to the present invention, the cameras may be respectively arranged on both sides of the wire so that optical axes of the cameras intersect a direction in which the wire extends.
By arranging the cameras in this way, the difference in the two-dimensional coordinates of each point in each two-dimensional image corresponding to one portion of the wire captured by each camera becomes large, the three-dimensional coordinates of one portion of the wire can be calculated with high accuracy, and the accuracy of measuring the shape of the wire can be improved.
In the wire shape measurement device according to the present invention, the control unit may inspect the shape of the wire based on the three-dimensional image of the wire generated, the control unit may inspect the shape of the wire by comparing the three-dimensional image of the wire generated with a reference shape of the wire, and the control unit may extract a shape parameter of the wire from the three-dimensional image of the wire generated, and inspect the shape of the wire by comparing the shape parameter extracted with a reference value of the shape parameter.
Thereby, it is possible to perform various shape measurements and shape inspections on the wire.
A wire three-dimensional image generation method according to the present invention is for a semiconductor device, which includes: a substrate; a semiconductor element mounted on the substrate; and a wire connecting an electrode of the semiconductor element and an electrode of the substrate, or connecting one electrode of the semiconductor element and another electrode of the semiconductor element. The wire three-dimensional image generation method includes: an image capturing step of respectively capturing two-dimensional images of the semiconductor device with a plurality of cameras; and a three-dimensional image generation step of generating a three-dimensional image of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by pattern matching using connection position information of a position where the wire is connected to the substrate or the semiconductor element and thickness information of the wire.
Since the three-dimensional image of the wire is generated from the two-dimensional images of the semiconductor device acquired by the cameras by pattern matching using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire, the three-dimensional image can be generated accurately in a short time.
In the wire three-dimensional image generation method according to the present invention, the three-dimensional image generation step may include: a two-dimensional coordinate extraction step of respectively extracting two-dimensional coordinates of each point in each two-dimensional image corresponding to one portion of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire; a three-dimensional coordinate calculation step of calculating three-dimensional coordinates of one portion of the wire by using the two-dimensional coordinates extracted; and an image generation step of generating a three-dimensional image of the wire based on the three-dimensional coordinates calculated.
Further, in the wire three-dimensional image generation method according to the present invention, the two-dimensional coordinate extraction step may repeatedly respectively extract two-dimensional coordinates of each point in each two-dimensional image corresponding to one portion of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire from a start end to a terminal end of the wire, to extract the two-dimensional coordinates of each point in each two-dimensional image respectively corresponding to a plurality of portions of the wire. The three-dimensional coordinate calculation step may calculate three-dimensional coordinates of the plurality of portions of the wire by using the two-dimensional coordinates in each two-dimensional image respectively corresponding to the plurality of portions of the wire extracted. The image generation step may generate a three-dimensional image from the start end to the terminal end of the wire based on the three-dimensional coordinates of the plurality of portions of the wire calculated.
Since the image of the wire is specified from the two-dimensional images of the entire semiconductor device captured by the cameras using the connection position information of the position where the wire is connected to the substrate or the semiconductor element and the thickness information of the wire, and the two-dimensional coordinates of the point on the wire image are extracted, the two-dimensional coordinates of the point on the image of the wire can be extracted from the two-dimensional images of the entire semiconductor device in a short time.
A wire shape measurement method according to the present invention is for a semiconductor device, which includes: a substrate; a semiconductor element mounted on the substrate; and a wire connecting an electrode of the semiconductor element and an electrode of the substrate, or connecting one electrode of the semiconductor element and another electrode of the semiconductor element. The wire shape measurement method includes: an image capturing step of respectively capturing two-dimensional images of the semiconductor device with a plurality of cameras; a three-dimensional image generation step of generating a three-dimensional image of the wire from the two-dimensional images of the semiconductor device acquired by the cameras by pattern matching using connection position information of a position where the wire is connected to the substrate or the semiconductor element and thickness information of the wire; and a measurement step of measuring a shape of the wire based on the three-dimensional image of the wire generated.
Further, the wire shape measurement method according to the present invention may include an inspection step of inspecting the shape of the wire based on the three-dimensional image of the wire generated, and the inspection step may inspect the shape of the wire by comparing the three-dimensional image of the wire generated with a reference shape of the wire. In addition, the inspection step may extract a shape parameter of the wire from the three-dimensional image of the wire generated, and inspect the shape of the wire by comparing the shape parameter extracted with a reference value of the shape parameter.
Thereby, it is possible to perform various shape measurements and shape inspections on the wire.
The present invention can provide a wire shape measurement device that is capable of measuring a shape of a wire with high accuracy in a short time.
Hereinafter, a wire shape measurement device 100 according to an embodiment will be described with reference to the drawings. As shown in
As shown in
Next, an operation of the wire shape measurement device 100 according to the embodiment will be described with reference to
As shown in step S101 of
Next, as shown in step S102 of
When the wire 30 is imaged by the camera 43 arranged on the Y-direction plus side of the semiconductor device 10, as shown in
Next, as shown in step S104 of
Similarly, as shown in
Since the two-dimensional coordinates (x31, y31) acquired from the image of the camera 43 and the two-dimensional coordinates (x41, y41) acquired from the image of the camera 44 in step S105 of
Therefore, in step S107 of
Then, in step S108 of
In step S109 of
In addition, the control unit 50 may also measure the shape parameters of the wire 30 from the generated three-dimensional image of the wire 30, for example, the shape dimensions such as the loop height which is the height from the start end 31 of the wire 30, the thickness of the crimp ball formed at the start end 31, the diameter of the crimp ball, etc., and compare each measured shape dimension with a reference value to perform the inspection.
As described above, since the wire shape measurement device 100 can generate the three-dimensional image of the wire 30 from the two-dimensional images of the semiconductor device 10 acquired by the cameras 43 and 44 by pattern matching using the two-dimensional coordinates (xs, ys) and (xe, ye) of the start end 31 and the terminal end 32 of the wire 30 and the diameter of the wire 30, the three-dimensional image can be generated accurately in a short time. Thus, it is possible to perform shape measurement and shape inspection on the wire 30 with high accuracy in a short time.
After inspection of the shape of the wire 30 extending in the Y direction, shape measurement and shape inspection are performed by performing the same processing based on the two-dimensional images captured by the cameras 41 and 42.
Furthermore, the two-dimensional images acquired by the four cameras 41 to 44, instead of the two cameras 41 and 42 or the two cameras 43 and 44, may be processed to generate the three-dimensional image of the wire 30. In addition, the two-dimensional images of four or more cameras may be processed to generate the three-dimensional image of the wire 30.
The above-described embodiment illustrates that the wire 30 for shape measurement or shape inspection connects the electrode 25 of the semiconductor element 20 and the electrode 12 of the substrate 11, but the present invention is not limited thereto. For example, the present invention can also be applied to the inspection of the shape of the wire 30 that continuously connects the electrode 25 of the semiconductor element 20 of each layer, the electrode 25 of the semiconductor element 20 of the lowermost layer, and the electrode 12 of the substrate 11 in the semiconductor device 10 which laminates a plurality of semiconductor elements 20 on the substrate 11. In such a case, the wire 30 connects one electrode 25 of the semiconductor element 20 of one layer and another electrode 25 of the semiconductor element 20 of another layer, and connects the electrode 25 of the semiconductor element 20 of the lowermost layer and the electrode 12 of the substrate 11.
Further, when a wire shape measurement method is executed using the wire shape measurement device 100 according to the embodiment, capturing the two-dimensional images of the semiconductor device 10 with the cameras and storing them in the memory 52, as shown in steps S102 and S103 shown in
Further, the step of extracting the two-dimensional coordinates, as in steps S104 to S106 of
Further, when a wire three-dimensional image generation method is executed using the wire shape measurement device 100 according to the embodiment, capturing the two-dimensional images of the semiconductor device 10 with the cameras and storing them in the memory 52, as shown in steps S102 and S103 of
10 semiconductor device; 11 substrate; 12, 25 electrode; 20 semiconductor element; 30 wire; 31 start end; 32 terminal end; 41 to 44 camera; 41a to 44a optical axis; 50 control unit; 51 CPU; 52 memory; 60 two-dimensional coordinate detection region; 100 wire shape measurement device.
Number | Date | Country | Kind |
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2019-081252 | Apr 2019 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2020/015653 | 4/7/2020 | WO | 00 |