Cutting device and method for manufacturing cut article

Abstract

A cutting device (1) for forming a groove on a second surface (41b) of a lead frame (41) of an object (4) to be cut comprises: a cutting table (22); a light source (33) that emits light to the second surface (41b) of the object (4) to be cut placed on the cutting table (22); a blocking member (34) that blocks a part of the light emitted from the light source (33); an imaging mechanism (31) that acquires a captured image of the second surface (41b); a height-changing mechanism (32) that can change the height of the imaging mechanism (31); and a calculation unit (35) that can execute an analysis process on the captured image. The imaging mechanism (31) has a lens (31b) that condenses the light on the second surface (41b), and an imaging unit (31a) that can acquire the captured image of the second surface (41b). The imaging unit (31a) acquires captured images at a plurality of different heights, and the calculation unit (35) calculates the height position of the second surface (41b) on the basis of the focusing state of the blocking member (34) in the captured images.

Description

Cutting device and method for manufacturing cut products

[0001] The present disclosure relates to a cutting device and a method for producing a cut product.

[0002] Conventionally, a lead frame to which a semiconductor chip or the like is fixed is sealed with resin and then cut into individual pieces using a cutting device. This process produces multiple electronic components. The electronic components are electrically connected to external wiring via lead frames extending from the semiconductor chip. Depending on the type of electronic component, the lead frame may not be completely cut in the thickness direction, but may be cut approximately halfway down the lead frame thickness with a wide blade to form a groove, and then the lead frame may be completely cut with a narrower blade (see, for example, Patent Document 1). Cutting the lead frame in this manner results in a step at the end of the lead frame.

[0003] Patent Document 1 discloses a QFN (Quad Flat Non-leaded package) in which a step is provided in the lead frame (electrode in Patent Document 1). The step in the lead frame is formed by the above-mentioned method.

[0004] Japanese Patent Application Laid-Open No. 2019-036660

[0005] When manufacturing a wettable flank type QFN with a step in the lead frame as disclosed in Patent Document 1, it is necessary to avoid cutting the lead frame completely when cutting the lead frame to about half its thickness to form a groove. Therefore, it is necessary to measure the height position of the lead frame before forming the groove and set the amount of cutting of the lead frame based on the measurement results. However, Patent Document 1 does not disclose a method for measuring the height position of the lead frame, and there is room for improvement.

[0006] Therefore, there is a demand for a cutting device and a method for manufacturing cut products that are capable of measuring the height position of a lead frame.

[0007] One embodiment of a cutting device according to the present disclosure is a cutting device that forms a groove in a second surface of a cutting object, the second surface being opposite to the first surface of a plate-shaped lead frame, the cutting device including: a cutting table on which the cutting object can be placed; a light source that irradiates light onto the second surface side of the cutting object placed on the cutting table; a shielding member that is disposed midway along a path of the light that propagates from the light source to the cutting object and that shields a portion of the light emitted from the light source; an imaging mechanism that acquires an image of the second surface side of the cutting object; and a height changing mechanism that can change the height of the imaging mechanism. and a calculation unit capable of performing analysis processing of the captured image, wherein the imaging mechanism has a lens that is positioned on the side of the object to be cut closer to the shielding member in the light path and that focuses the light from the light source onto the second surface, and an imaging unit that is positioned on the opposite side of the object to the cutting table and that is capable of acquiring the captured image by receiving the light reflected by the object to be cut, wherein the imaging unit acquires the captured images at a plurality of different heights changed by the height change mechanism, and the calculation unit calculates the height position of the second surface based on the focus state of the shielding member in the plurality of captured images.

[0008] One embodiment of the method for manufacturing cut products according to the present disclosure includes a groove forming process for forming the groove in the cutting object using the cutting device described above, and a singulation process for cutting the cutting object with the groove formed therein into a plurality of cut products.

[0009] According to the embodiments of the present disclosure, it is possible to provide a cutting device capable of measuring the height position of a lead frame and a method for manufacturing a cut product.

[0010] FIG. 1 is a plan view of a package substrate; FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1; FIG. 3 is a plan view of a cutting device; FIG. 4 is a front view of the cutting device; FIG. 5 is a cross-sectional view of a package substrate using the cutting device; FIG. 6 is a cross-sectional view of a package substrate singulation process using the cutting device; FIG. 7 is a perspective view of an electronic component singulated by the cutting device; FIG. 8 is a schematic diagram of the configuration of a measurement unit when the shielding member is not focused; FIG. 9 is a partial plan view of a substrate on which a cross mark is formed; FIG. 10 is a diagram of a process of calculating a peak contrast value using the measurement unit; FIG. 11 is a graph of the peak contrast value versus the distance between the holding post and the second surface; FIG. 12 is a flowchart of a process of calculating the distance between the holding post and the second surface; FIG. 13 is a schematic diagram of the configuration of a measurement unit when the shielding member is focused.

[0011] Hereinafter, embodiments of the cutting device and the method for manufacturing cut pieces according to the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are examples for explaining the cutting device and the method for manufacturing cut pieces, and the cutting device and the method for manufacturing cut pieces are not limited to these embodiments. Therefore, the cutting device and the method for manufacturing cut pieces according to the present disclosure can be implemented in various forms without departing from the spirit thereof.

[0012] A substrate on which elements such as semiconductor chips are fixed is sealed with resin to form a package substrate, which is then cut into individual pieces to produce multiple electronic components. A dedicated cutting device is used to cut the resin-sealed package substrate.

[0013] Resin sealing of substrates is performed by placing the substrate in a molding die of a resin molding device and supplying liquid molten resin into the molding die. The molten resin may be a thermoplastic resin or a thermosetting resin. Thermosetting resin reduces in viscosity when heated, and when further heated, it polymerizes and hardens to become a hardened resin. When resin sealing a substrate on which elements such as semiconductor chips are fixed, it is desirable to use a thermosetting resin. The elements fixed to the substrate are protected by the sealing resin.

[0014] The cutting apparatus manufactures multiple electronic components by cutting package substrates. Here, the concept of the term "cutting" includes separating an object to be cut into multiple individual cut products and removing a portion of the object to be cut to form a groove in the thickness direction. Hereinafter, cutting that separates an object to be cut into multiple individual cut products will be referred to as a "full cut," and cutting that removes a portion of the object to be cut to form a groove in the thickness direction without separating the object to be cut will be referred to as a "half cut." Below, we will first explain package substrates, and then explain a cutting apparatus that cuts package substrates.

[0015] [Package Substrate Configuration] FIG. 1 is a plan view of a package substrate 4 (an example of an object to be cut) according to this embodiment, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 . The type of package substrate 4 targeted in this embodiment is not particularly limited. The package substrate 4 may be, for example, a wettable flank QFN (Quad Flat Non-leaded) package. As shown in FIGS. 1 and 2 , the package substrate 4 includes a rectangular plate-shaped substrate 41 (an example of a lead frame) made of a metal such as a copper plate, and a rectangular resin layer 42 that resin-seals one surface of the substrate 41. Hereinafter, the surface of the substrate 41 on which the resin layer 42 is formed is referred to as a first surface 41a, and the surface opposite the first surface 41a is referred to as a second surface 41b. A lead frame may be used as the substrate 41.

[0016] In this embodiment, a first surface 41a of the lead frame (substrate 41) has a plurality of semiconductor chip mounting portions (die pads, not shown) arranged in a matrix, and electronic elements 43, such as semiconductor chips, resistor elements, and capacitor elements, are fixed to each semiconductor chip mounting portion. In this embodiment, a total of 12 electronic elements 43 are fixed to the substrate 41, two in the short direction and six in the long direction. The substrate 41 is made of a metal such as copper (Cu) or 42 alloy (Fe—Ni) and is conductive. A lead-free metal plating layer or a lead-free solder plating layer (not shown) is often pre-formed on the surface of the substrate 41. Numerous leads are arranged around each die pad, serving as terminals for connection to the outside. These numerous leads are each connected to tie bars, which are metal frames arranged in a grid pattern on the substrate 41. In addition, a plurality of electrodes (not shown) provided on each electronic element 43 are electrically connected to the respective leads arranged around the die pad via bonding wires made of gold or copper wire.

[0017] The substrate 41 of this embodiment is composed of a rectangular used area 411 and a non-used area 412 surrounding the used area 411. The non-used area 412 includes the outer edge of the substrate 41. It is not used as a product and is removed after cutting. On the other hand, the used area 411 is used as a product and includes the die pad, leads, and tie bars of the lead frame described above. The resin layer 42 is molded in a rectangular shape to cover the used area 411 of the substrate 41 and a portion of the non-used area 412 outside the used area 411. In other words, the electronic element 43 and bonding wires arranged in the used area 411 are encapsulated by the resin layer 42. By forming such a resin layer 42, a step is formed between the first surface 41a of the substrate 41 and the end face of the resin layer 42 (the upper surface in FIG. 2 ) by the thickness of the resin layer 42. Note that the substrate 41 constituting the package substrate 4 is not limited to a lead frame.

[0018] 3 and 4 show the cutting device 1 according to this embodiment. The cutting device 1 mainly includes a cutting unit 10 (an example of a first cutting mechanism and a second cutting mechanism), a holding unit 20, a measuring unit 30, and a control unit 50. That is, in this cutting device 1, the package substrate 4 held by the holding unit 20 is cut by the cutting unit 10. Before cutting, the measuring unit 30 measures the height position of the second surface 41b of the substrate 41 for cutting the package substrate 4. The control unit 50 also controls the series of cutting processes.

[0019] The cutting apparatus 1 may include units other than those described above. For example, the cutting apparatus 1 may include a substrate supply unit that supplies package substrates 4, an inspection unit that inspects the package substrates 4 and / or electronic components 40 (an example of a cut product), a cleaning unit that cleans and / or dries the cut electronic components 40, a transport unit that transports the cut electronic components 40 to a storage section, and the like. The configurations of the cutting unit 10, the holding unit 20, the measuring unit 30, and the control unit 50 will be described in detail below. In this embodiment, as shown in FIGS. 3 and 4 , the direction perpendicular to the plate surface of the blade 11 (described later) is defined as the X-axis direction. The direction perpendicular to the X-axis direction and parallel to the mounting surface 22 a of the table 22 (an example of a cutting table) is defined as the Y-axis direction, and the direction perpendicular to the mounting surface 22 a, i.e., the direction perpendicular to the X-axis direction and the Y-axis direction, is defined as the Z-axis direction.

[0020] As shown in FIGS. 3 and 4 , the cutting unit 10 is disposed above the holding unit 20 and configured to cut the package substrate 4. The cutting unit 10 includes a blade 11, a spindle 13, and a spindle movement mechanism (not shown) that moves the spindle 13 to a desired position within the cutting device 1. The spindle 13 includes a shaft 13a that rotates the blade 11 (described below). The shaft 13a of the spindle 13 extends in the X-axis direction. That is, the shaft 13a and the blade 11 rotate around the X-axis. The spindle 13 is configured to be movable in the X-axis and Z-axis directions in FIGS. 3 and 4 by a spindle movement mechanism (not shown). The operation of the spindle movement mechanism, i.e., the movement of the spindle 13 and the position of the spindle 13 in the X-axis and Z-axis directions, is controlled by a control unit 50 (described below). Hereinafter, the Z-axis direction in FIGS. 3 and 4 may be referred to as the height direction of the spindle 13 or the blade 11. The control unit 50 can grasp the position of the spindle 13 in the X-axis direction and the Z-axis direction based on information from the spindle movement mechanism.

[0021] The blade 11 has a disk shape with a cutting edge formed on its outer periphery. The blade 11 is detachably attached to a shaft 13a of the spindle unit 13. The blade 11 is configured to be movable in the X-axis and Z-axis directions in Figures 3 and 4 together with the spindle unit 13 to which the blade 11 is attached.

[0022] The blade 11 attached to the shaft 13a of the spindle 13 is configured to rotate at high speed by transmitting rotation from the spindle 13 via the shaft 13a, causing the outer blade to perform half cuts and full cuts on the package substrate 4. Hereinafter, the half-cutting blade 11 will be referred to as the first blade 11a (an example of a blade), and the full-cutting blade 11 will be referred to as the second blade 11b. Blade 11 will collectively refer to the first blade 11a and the second blade 11b. The first blade 11a has a first thickness, and the second blade 11b has a second thickness that is smaller than the first thickness. In other words, the thickness of the second blade 11b is thinner than the thickness of the first blade 11a (see FIGS. 5A and 5B ). In this embodiment, either the first blade 11a or the second blade 11b is attached to the spindle 13 to perform cutting. The first blade 11a and the second blade 11b are detachable and replaceable from the spindle 13.

[0023] The holding unit 20 includes a table 22 and a table movement mechanism 24. The package substrate 4 is placed on the mounting surface 22a of the table 22 so that the resin layer 42 is in contact with the mounting surface 22a, and is held by a method such as air suction. The table movement mechanism 24 can move the table 22 along the Y-axis direction and rotate it 90 degrees around the Z-axis. With the package substrate 4 held by the holding unit 20, the table 22 moves relative to the blade 11 in the Y-axis direction and rotates around the Z-axis, thereby enabling the package substrate 4 to be cut along its longitudinal and lateral directions.

[0024] There is no problem as long as the spindle unit 13 is movable relative to the table 22. Therefore, instead of moving the spindle unit 13 in the X-axis direction, the table 22 may be moved in the X-axis direction. Also, instead of moving the spindle unit 13 in the Z-axis direction, the table 22 may be moved in the Z-axis direction. Furthermore, instead of moving the table 22 in the Y-axis direction, the spindle unit 13 may be moved in the Y-axis direction.

[0025] 5A to 5C , when cutting package substrate 4 to manufacture electronic components 40, package substrate 4 is cut in the order of half-cutting and full-cutting. That is, the method for manufacturing electronic components 40 includes a groove forming step in which cutting device 1 is used to half-cut substrate 41 of package substrate 4 to form half-cut grooves 44 (an example of a groove) of a desired depth, and a singulation step in which full-cutting is performed on package substrate 4 with the grooves formed therein to singulate package substrate 4 into a plurality of electronic components 40. Note that the cross sections of package substrate 4 shown in FIGS. 5A to 5C are cross sections along the longitudinal direction.

[0026] In the groove forming process shown in FIG. 5A , a first blade 11a is attached to the shaft 13a of the spindle portion 13. The package substrate 4 is placed on the table 22 so that the longitudinal direction of the package substrate 4 is parallel to the plate surface of the first blade 11a. With the package substrate 4 held on the table 22, the first blade 11a is positioned between adjacent electronic elements 43 (see FIG. 1 ) among the multiple electronic elements 43 fixed to the package substrate 4. The first blade 11a is then rotated in place while the table 22 is moved along the Y-axis direction, whereby the longitudinal direction of the package substrate 4 along the Y-axis direction is half-cut by the first blade 11a, forming one half-cut groove 44 (in one row) in the substrate 41 of the package substrate 4. Specifically, in the groove forming process, a portion of the substrate 41 in the thickness direction of the package substrate 4 (e.g., approximately half the plate thickness of the substrate 41 (lead frame)) is removed. After one half-cut groove 44 is formed, the first blade 11a is moved in the X direction to position the first blade 11a between another adjacent electronic element 43. Thereafter, the table 22 is moved again along the Y-axis direction to form a new half-cut groove 44 in the package substrate 4. This process is repeated to form a plurality of half-cut grooves 44 (for example, three in the longitudinal direction of the package substrate 4).

[0027] Next, while holding the package substrate 4, the table 22 is rotated 90 degrees around the Z axis so that the short-side direction of the package substrate 4 is parallel to the plate surface of the first blade 11a. Then, as described above, the table 22 is moved along the Y-axis direction while rotating the first blade 11a in place, and the first blade 11a forms half-cut grooves 44 in the short-side direction of the package substrate 4. This is repeated to form multiple half-cut grooves 44 (e.g., seven in the short-side direction of the package substrate 4). In this way, a lattice-shaped half-cut grooves 44 extending in the longitudinal and short-side directions of the package substrate 4 are formed, thereby completing the groove forming process.

[0028] In the singulation process shown in FIG. 5B , first, the first blade 11a is removed from the spindle portion 13, and the second blade 11b is attached. Then, a full cut is performed with the second blade 11b. Specifically, the second blade 11b cuts the remaining portion of the substrate 41 and the resin layer 42 along the half-cut groove 44 at approximately the center in the extension direction of the half-cut groove 44. The cutting procedure is the same as in the half-cut case, so a detailed description will be omitted. This separates the lattice-shaped half-cut grooves 44, and the package substrate 4 is singulated into a plurality of electronic components 40 (12 in this embodiment) as shown in FIG. 5C .

[0029] The measuring unit 30 measures the height position of the second surface 41b of the substrate 41 of the package substrate 4. By accurately measuring the height position of the second surface 41b, it is possible to form a half-cut groove 44 of a desired depth in the substrate 41 with the first blade 11a. As shown in FIG. 6 , the measuring unit 30 includes an imaging mechanism 31, a height changing mechanism 32, a light source 33, a shielding member 34, a calculation unit 35, a half mirror 36 (an example of a mirror), and a CCS (Contact Cutter Setup) block 37 (an example of a reference block).

[0030] The imaging mechanism 31 has the function of capturing an image of the second surface 41b of the substrate 41 of the package substrate 4 and includes a camera 31a (an example of an imaging unit), a lens 31b, and a rectangular cylindrical first tube 31c connecting the camera 31a and the lens 31b. The camera 31a captures an image 31d of the second surface 41b by forming an image on an imaging element (not shown), such as a CCD or CMOS, built in the camera 31a (see FIG. 8A). Therefore, the light receiving surface of the imaging element of the camera 31a is positioned to face the second surface 41b. The lens 31b collects light reflected by the second surface 41b, transmits it through (propagates) the inside of the first tube 31c, and forms an image on the imaging element of the camera 31a. Therefore, the lens 31b is positioned between the camera 31a and the second surface 41b. The camera 31a is attached to one end of the first cylinder 31c, and the lens 31b is attached to the other end of the first cylinder 31c. In other words, the imaging mechanism 31 is integrated.

[0031] The height changing mechanism 32 includes a main pillar 32a extending in the Z-axis direction and a holding pillar 32b extending from the main pillar 32a along the X-axis direction. The holding pillar 32b is configured to be movable along the Z-axis direction relative to the main pillar 32a. The holding pillar 32b holds the first tube 31c, and movement of the holding pillar 32b along the Z-axis direction causes the imaging mechanism 31 to move along the Z-axis direction. The movement of the holding pillar 32b is performed by, for example, a motor (not shown). The control unit 50 can determine the height position of the holding pillar 32b, i.e., the height position of the camera 31a, by determining the number of rotations of the motor when moving the holding pillar 32b up and down.

[0032] The light source 33 illuminates the second surface 41b of the substrate 41 of the package substrate 4 and is composed of an LED or the like. The light source 33 is attached to one end of a square cylindrical second tube 33a, and light emitted from the light source 33 travels inside the second tube 33a. The other end of the second tube 33a is connected to the side surface of the first tube 31c, and the light from the light source 33 enters the internal space of the first tube 31c. That is, a hole is formed in the side surface of the first tube 31c, and the hole is blocked by the second tube 33a. The second tube 33a extends along the X-axis direction.

[0033] A half mirror 36 is disposed inside the first barrel 31c. The half mirror 36 reflects light that has passed through the second barrel 33a along the X-axis direction and propagates it toward the second surface 41b along the Z-axis direction. The half mirror 36 transmits light that has been reflected by the second surface 41b and then collected by the lens 31b, allowing it to enter the imaging element of the camera 31a. That is, light emitted from the light source 33 passes through the inside of the second barrel 33a, enters the first barrel 31c, is reflected by the half mirror 36, and travels toward the second surface 41b. After being reflected by the second surface 41b, the light passes through the lens 31b and the half mirror 36 and enters the camera 31a. This allows the imaging element of the camera 31a to capture an image 31d of the second surface 41b.

[0034] A shielding member 34 is disposed inside the second tube 33a. The shielding member 34 is a frame body with a rectangular outer shape. The inside (center) of the shielding member 34 has an opening 34a with a shape similar to the outer shape (i.e., rectangular). When light is emitted from the light source 33 into the second tube 33a, the light passes through the central region of the second tube 33a and enters a location adjacent to the shielding member 34, i.e., the opening 34a provided inside the shielding member 34. The light then passes through (propagates) the opening 34a and travels inside the second tube 33a toward the first tube 31c. On the other hand, light that enters the shielding member 34 through the outer edge region of the second tube 33a cannot pass through the shielding member 34 and is reflected or absorbed. In other words, the shielding member 34 blocks light that enters from the light source 33 through the outer edge region. The outer edge region is the region of the surface of the second tube 33a closest to the inner surface. The shielding member 34 is attached to a sliding cylinder 34c that is slidably disposed inside the second cylinder 33a, so that the shielding member 34 is movable along the X-axis direction by movement of the sliding cylinder 34c along the X-axis direction.

[0035] In this way, the imaging mechanism 31, the light source 33, the second cylinder 33a, the shielding member 34, and the half mirror 36 are integrated into one unit. All of these are held by the holding column 32b of the height changing mechanism 32, and move along the Z-axis direction as the holding column 32b moves along the Z-axis direction.

[0036] The calculation unit 35 is included in the control unit 50. The control unit 50 includes a processor such as a CPU (Central Processing Unit) and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The calculation unit 35 is a processor. The control unit 50 controls the operation of the cutting unit 10, the holding unit 20, and the measuring unit 30 of the cutting device 1 by executing a control program stored in the storage device using the processor. The operation of the cutting device 1 is performed based on operation commands from the control unit 50, unless otherwise specified. In the following description, explanation of the operation commands from the control unit 50 will generally be omitted, and the operation commands from the control unit 50 will be explained as necessary. The control unit 50 may be configured integrally with each unit or separately from each unit.

[0037] The calculation unit 35 calculates the height position (absolute position and / or relative position) of the second surface 41b of the substrate 41 of the package substrate 4 measured by the measurement unit 30. In this embodiment, the height position of the second surface 41b of the substrate 41 refers to the height from a reference position (hereinafter referred to as reference height P) in the height direction to the second surface 41b when an arbitrary point is set as the reference position. In this embodiment, the reference height P is between the upper surface 37a of the CCS block 37 and the upper surface of the table moving mechanism 24.

[0038] The CCS block 37 is attached to the side of the table 22 and can move together with the table 22 .

[0039] 6 to 11 , a method for measuring the height position of the second surface 41b of the substrate 41 of the package substrate 4 will be described. Before starting the measurement, the positions of the shielding member 34, the half mirror 36, and the lens 31b are adjusted so that when the second surface 41b of the substrate 41 is imaged with the camera 31a, a confocal image 31d is obtained in which both the second surface 41b and the shielding member 34 are in focus. Note that FIG. 6 shows a state in which the shielding member 34 is not focused on the second surface 41b of the substrate 41, and FIG. 11 shows a state in which the shielding member 34 is focused on the second surface 41b of the substrate 41.

[0040] First, the package substrate 4 is placed on the table 22 and held there by a method such as air suction. Then, the height changing mechanism 32 moves the imaging mechanism 31 including the camera 31a above the package substrate 4 and moves it along the Z-axis direction to a predetermined height position (hereinafter simply referred to as the predetermined height position) (step S1). The predetermined height position may be, for example, a height position where the lens 31b is close enough to the substrate 41 without contacting it. Alternatively, the lens 31b may be separated from the substrate 41 to the maximum height position at which the camera 31a can capture an image of the second surface 41b and measure the height position.

[0041] The height position of the camera 31a is configured to be grasped as a height from a reference height P. This height position of the camera 31a is input to the calculation unit 35. In addition, the focal length L of the camera 31a in the imaging mechanism 31 is stored in advance in a storage device.

[0042] Light from the light source 33 is irradiated onto the second surface 41b of the substrate 41 of the package substrate 4, and the second surface 41b is imaged with the camera 31a (step S2). At this time, it is preferable to image a cross mark 41c (an example of a cutting mark) formed on the second surface 41b, as shown in FIG. 7 . The cross mark 41c is formed on the edge of the second surface 41b and indicates the cutting locations for half-cutting and full-cutting the substrate 41, i.e., the locations where the blade 11 cuts the package substrate 4. The cross mark 41c is formed by printing or other methods along at least two adjacent sides of the second surface 41b of the rectangular substrate 41. The location imaged by the camera 31a to measure the height position of the second surface 41b of the substrate 41 may be any location on the second surface 41b. However, it is preferable to capture an image 31d by capturing an image of the cross marks 41c that are the cutting locations of the half cut and full cut of the substrate 41, because this makes it possible to measure the height position of the cutting location on the second surface 41b of the substrate 41 and to grasp the cutting location of the package substrate 4. This makes it possible to form half-cut grooves 44 of a desired depth at the desired cutting location of the substrate 41.

[0043] The imaging element of the camera 31a acquires a captured image 31d as shown in FIG. 8(a). In this embodiment, a shielding member 34 is disposed between the light source 33 and the second surface 41b of the substrate 41, so that light incident on the shielding member 34 is blocked and does not reach the second surface 41b. Therefore, in the captured image 31d acquired by the camera 31a, the edge 31e (area shielded by the shielding member 34) appears black (dark) and the center 31f (area where light is transmitted by the opening 34a adjacent to the shielding member 34) appears bright, revealing the cross mark 41c. In other words, in the captured image 31d, the edge 31e is a dark area and the center 31f is a bright area. Data on the captured image 31d acquired by the camera 31a capturing an image of the second surface 41b and the distance D (see FIG. 6) between the camera 31a and the reference height P are output to the control unit 50.

[0044] In the control unit 50, the calculation unit 35 sums the pixel values ​​(brightness values) of each pixel constituting each of multiple columns (vertical rows of multiple pixels in FIG. 8 ) near the boundary between the edge portion 31 e and the central portion 31 f of the input captured image 31 d data, as shown in FIG. 8( b), to calculate a total pixel value for each column. Because FIG. 8( b) shows a state in which the shielding member 34 is focused, the total pixel value has two values, as shown in FIG. 8( c). Next, the calculation unit 35 generates an approximation curve for the total pixel value, as shown in FIG. 8( d), and further differentiates the approximation curve to generate a differential curve as shown by the solid line in FIG. 8( e). In the differential curve, the differential value is the amount of change in pixel value, and therefore represents the contrast value, which is the contrast ratio between the edge portion 31 e and the central portion 31 f of the captured image 31 d. In other words, generating a differential curve is synonymous with calculating a contrast value. The location where the calculated contrast value (differential value) is maximum is the location where the change in pixel value is greatest, and therefore the location where the contrast value is maximum is the boundary between the edge portion 31e (dark portion) and the center portion 31f (bright portion) of the captured image 31d. Hereinafter, the maximum contrast value may be referred to as the peak contrast value. Next, the calculation unit 35 extracts the peak contrast value from the contrast values ​​and stores it in the storage device (step S3). Note that the imaging of the second surface 41b of the substrate 41 by the camera 31a at a predetermined height, the calculation of the contrast value by the calculation unit 35, and the extraction and storage of the peak contrast value may be performed for one cross mark 41c or for multiple cross marks 41c. If the imaging is performed for multiple cross marks 41c, the calculation unit 35 stores the average of the multiple peak contrast values ​​in the storage device.

[0045] After the camera 31a captures the image of the second surface 41b of the substrate 41 at a predetermined height, the calculator 35 calculates the contrast value, and the peak contrast value is extracted and stored, the camera 31a (holding column 32b) is moved a predetermined distance (No in step S4, step S6), and the camera 31a captures the image of the second surface 41b at the new height and extracts the peak contrast value (steps S2 and S3). This process is performed a predetermined number of times or for a predetermined range of heights in the Z-axis direction, and the measurement is stopped after completion of the process (Yes in step S4).

[0046] FIG. 8 shows a state in which the shielding member 34 is in focus, so the differential curve shown by the solid line in FIG. 8(e) rises sharply toward the peak contrast value, and the peak contrast value itself is large. That is, dark and bright areas are clearly separated. However, when the shielding member 34 is out of focus (not shown), the area near the boundary between the edge portion 31e and the center portion 31f in the image 31d captured by the camera 31a appears gray, and the boundary between the edge portion 31e (dark area) and the center portion 31f (bright area) cannot be clearly separated. Therefore, the sum of pixel values ​​for each column parallel to the boundary between the edge portion 31e and the center portion 31f gradually increases from the dark area to the bright area. In such a case, as shown by the dashed line in FIG. 8(e), the differential curve rises more gradually toward the peak contrast value, and the peak contrast value itself is smaller, compared to the solid line (when the shielding member 34 is in focus). FIG. 9 shows the relationship between the distance D between the camera 31a and the second surface 41b of the substrate 41 and the peak contrast value.

[0047] 9, the peak contrast value changes as the distance D changes, and the distance D1 at which the peak contrast value is maximized, i.e., the contrast ratio is highest, is the distance at which the shielding member 34 is focused. As shown in FIG. 11, the distance D1 is the distance D from the reference height P to the camera 31a when the shielding member 34 is focused on the second surface 41b of the substrate 41 (step S5). At this time, the distance between the camera 31a and the second surface 41b of the substrate 41 is equal to the focal length L. Therefore, the distance D2 from the reference height P to the second surface 41b (the height position of the second surface 41b) is calculated by subtracting the focal length L from the distance D1 (D2 = D1 - L).

[0048] Next, the calculation unit 35 irradiates the upper surface 37a of the CCS block 37 with light from the light source 33 to obtain a captured image of the upper surface 37a (not shown; an example of a block captured image). Then, using a method similar to that used to calculate the distance D2 (height position of the second surface 41b) described above, the calculation unit 35 calculates the distance D3 from the reference height P to the upper surface 37a of the CCS block 37. The calculation unit 35 then calculates the distance D4 from the upper surface 37a of the CCS block 37 to the second surface 41b of the substrate 41 based on the difference between the distances D2 and D3 (D4 = D2 - D3).

[0049] Such measurements and calculations of distance D4 are performed at multiple locations on the package substrate 4, for example, at the four corners (four locations) of the rectangular substrate, or at the four corners and the center of the long side of the rectangular substrate (six locations in total). If the values ​​of distance D4 at multiple locations vary due to warping of the package substrate 4 or other reasons, distance D4 is set so that the depth of the half-cut groove 44 falls within the allowable tolerance regardless of the location at which the cut is made. If a single distance D4 does not allow the depth of the half-cut groove 44 to fall within the allowable tolerance at any of the cut locations, two or more different distances D4 are set so that the depth of the half-cut groove 44 falls within the allowable tolerance at all cut locations.

[0050] Next, the spindle 13 is moved by a spindle moving mechanism (not shown) to bring the first blade 11a into contact with the upper surface 37a of the CCS block 37. Contact between the first blade 11a and the CCS block 37 may be detected by any method, such as detecting electrical continuity between the first blade 11a and the CCS block 37. Specifically, the method for detecting electrical continuity between the first blade 11a and the CCS block 37 is as follows. The CCS block 37 and the spindle 13 are made of a conductive material such as metal. For example, the CCS block 37 and the spindle 13 are electrically connected in advance. Furthermore, because the spindle 13, shaft 13a, and first blade 11a are all made of metal, electrical continuity exists between the spindle 13 and the first blade 11a. This causes the spindle 13 to move in the Z-axis direction by the spindle moving mechanism, bringing the first blade 11a closer to the upper surface 37a of the CCS block 37. When the CCS block 37 and the first blade 11a are not in contact with each other, no electrical continuity occurs among the CCS block 37, the spindle 13, and the first blade 11a. However, the moment the CCS block 37 and the first blade 11a come into contact with each other, electrical continuity occurs among the CCS block 37, the spindle 13, and the first blade 11a. This electrical continuity is detected by a known method. The detection of electrical continuity means that the lowest point of the first blade 11a is located on the upper surface 37a of the CCS block 37.

[0051] From a state in which the first blade 11a contacts the upper surface 37a of the CCS block 37, the spindle 13 is raised by a distance D4 using the spindle movement mechanism. This brings the first blade 11a and the second surface 41b of the substrate 41 to the same height. Specifically, the height position of the first blade 11a is the height position of the lowest point of the first blade 11a, i.e., the height position of the contact point of the first blade 11a with the upper surface 37a of the CCS block 37. Finally, the spindle 13 is lowered by the depth of the half-cut groove 44, and at that height position, the first blade 11a is rotated in place and the table 22 is moved along the Y-axis. This allows the half-cut groove 44 to be formed in the substrate 41 to the desired depth. Alternatively, the spindle 13 may be directly moved from a state in which the first blade 11a contacts the upper surface 37a of the CCS block 37 to a height at which the half-cut groove 44 is formed in the substrate 41.

[0052] In this way, by changing the height of the camera 31a (the height of the holding posts 32b of the height changing mechanism 32) to capture an image of the second surface 41b of the substrate 41, calculating the contrast value of the differential curve, and extracting the peak contrast value, it is possible to calculate the height position of the second surface 41b of the substrate 41 (lead frame) from the reference height P and align the height positions of the first blade 11a and the second surface 41b of the substrate 41, without using an expensive device such as a laser sensor. This makes it possible to perform a half-cut on the substrate 41 of the package substrate 4 using the cutting device 1 and form a half-cut groove 44 of a desired depth.

[0053] Since the first blade 11a is somewhat worn when the half-cut groove 44 is formed, it is preferable to bring the first blade 11a into contact with the upper surface 37a of the CCS block 37 each time a half-cut groove 44 is formed, and adjust the height difference between the second surface 41b of the substrate 41 and the lowest point of the first blade 11a to a value obtained by subtracting the depth of the half-cut groove 44 from the distance D4 before performing the half-cut.

[0054] Furthermore, the height position of the first blade 11a does not have to be calculated using the upper surface 37a of the CCS block 37 as the reference height. For example, the reference height may be the height of the axis of the shaft 13a of the spindle 13 when the first blade 11a is moved to its lowest point by the spindle movement mechanism. Furthermore, the reference height of the first blade 11a does not have to coincide with the reference height positions of the camera 31a and the substrate 41.

[0055] Another embodiment of the present invention will be described below, in which the same components as those in the above embodiment will be described using the same terms and symbols to facilitate understanding.

[0056] (1) In the above embodiment, the first blade 11a and the second blade 11b are used interchangeably with one spindle portion 13. However, the spindle portion 13 for the first blade 11a and the spindle portion 13 for the second blade 11b may be separate.

[0057] (2) In the above embodiment, the imaging of the second surface 41b and the extraction of the peak contrast value are performed a predetermined number of times or within a predetermined range, but this is not limiting. For example, the measurement may be stopped when the peak contrast value changes from increasing to decreasing. In this way, the distance D1 at which the peak contrast value is maximized can be obtained.

[0058] (3) In the above embodiment, the sliding cylinder 34c is disposed inside the second cylinder 33a. However, the second cylinder 33a may be divided into two parts, and the sliding cylinder 34c may be disposed between the two parts so as to be slidable therebetween.

[0059] (4) In the above embodiment, the shielding member 34 is a rectangular frame, but this is not limited to this. The shielding member 34 can have any shape as long as one of the boundaries between the portion that blocks light from the light source 33 and the portion that transmits light is linear.

[0060] (5) In the above embodiment, the sum of pixel values ​​for each of a plurality of columns near the boundary between the edge portion 31 e and the central portion 31 f of the shielding member 34 is calculated in a vertical arrangement, but this is not limited to this. For example, if the upper center of the left and right sides in FIG. 8A is selected as the vicinity of the boundary between the edge portion 31 e and the central portion 31 f, the sum of pixel values ​​for each of the columns may be calculated in a horizontal arrangement.

[0061] (6) In the above embodiment, the camera 31a captures the image of the cross mark 41c. However, the camera 31a may capture an image of something other than the cross mark 41c.

[0062] (7) In the above embodiment, the cross marks 41c are formed as cutting points for half-cutting and full-cutting the substrate 41. However, any mark other than the cross marks 41c may be used.

[0063] (8) In the above embodiment, the lens 31b is disposed between the half mirror 36 and the substrate 41. However, the lens 31b may be disposed not only in this location but also between the half mirror 36 and the camera 31a.

[0064] [Outline of the above embodiment] The cutting method, the method for manufacturing the cut product, and the cutting device 1 described in the above embodiment will be outlined below.

[0065] <1> A cutting device (1) for forming a groove (44) on a second surface (41b) opposite to the first surface (41a) of a cutting object (4) having a resin layer (42) molded on a first surface (41a) of a plate-shaped lead frame (41), the cutting device (1) including: a cutting table (22) on which the cutting object (4) can be placed; a light source (33) for irradiating light onto the second surface (41b) side of the cutting object (4) placed on the cutting table (22); a shielding member (34) disposed midway along the path of light propagating from the light source (33) to the cutting object (4) and for shielding a portion of the light emitted from the light source (33); an imaging mechanism (31) for acquiring an image (31d) of the second surface (41b) side of the cutting object (4); and a height changing mechanism for changing the height of the imaging mechanism (31). (32) and a calculation unit (35) capable of performing analysis processing of the captured image (31d), wherein the imaging mechanism (31) is arranged closer to the object to be cut (4) than the shielding member (34) in the light path and has a lens (31b) that focuses light from the light source (33) on the second surface (41b), and an imaging unit (31a) that is arranged on the opposite side of the cutting table (22) with respect to the object to be cut (4) and is capable of acquiring the captured image (31d) by receiving light reflected by the object to be cut (4), wherein the imaging unit (31a) acquires the captured image (31d) at a plurality of different heights changed by the height change mechanism (32), and the calculation unit (35) calculates the height position of the second surface (41b) based on the focusing state of the shielding member (34) in the plurality of captured images (31d).

[0066] In this embodiment, the height position of the second surface (41 b) is calculated based on the in-focus state of the shielding member (34) in the captured image (31 d), so that the height position of the second surface (41 b) can be accurately grasped. This makes it possible to obtain a cutting device (1) that can form a groove (44) of a desired depth on the second surface (41 b) of the workpiece (4) based on the calculated height position.

[0067] <2> In the cutting device (1) described above in <1>, the shielding member (34) may be a frame that shields an outer edge region of the light emitted from the light source (33).

[0068] In this embodiment, a captured image (31d) with a high contrast ratio can be obtained by blocking a portion of the light emitted from the light source (33) with the shielding member (34), thereby obtaining a captured image (31d) in which the shielding member (34) is accurately focused.

[0069] <3> In the cutting device (1) described in <1> or <2> above, the calculation unit (35) may calculate a contrast ratio between the shielding member (34) and a location adjacent to the shielding member (34) in each of the multiple captured images (31d), and calculate the height position of the second surface (41b) based on the height of the imaging unit (31a) when the captured image (31d) with the highest contrast ratio among the multiple calculated contrast ratios was acquired.

[0070] When the contrast ratio of the captured image (31d) increases, the boundary between the bright and dark areas becomes clearer, and the shielding member (34) approaches a focused state. In this embodiment, the height position of the second surface (41b) is calculated based on the height of the imaging unit (31a) when the captured image (31d) with the highest contrast ratio is acquired, so that the captured image (31d) in which the shielding member (34) is accurately focused can be obtained.

[0071] <4> In the cutting device (1) described in any one of <1> to <3> above, the shielding member (34) may be arranged to be movable between the light source (33) and the object to be cut (4).

[0072] In this embodiment, it is possible to easily obtain a confocal image (31d) in which both the second surface (41b) and the shielding member (34) are in focus.

[0073] <5> In the cutting device (1) described in any one of <1> to <4> above, the height of the light source (33) and the shielding member (34) may be changed in conjunction with a change in the height of the imaging unit (31 a) by the height change mechanism (32).

[0074] In this embodiment, a captured image (31d) of the second surface (41b) can be obtained simply by changing the height of the imaging section (31a).

[0075] <6> The cutting device (1) described in any one of <1> to <5> above further includes a mirror (36) that is arranged between the shielding member (34) and the lens (31b) in the light path and reflects the light toward the second surface (41b), and the height of the mirror (36) may be changed in conjunction with a change in the height of the imaging unit (31a) by the height change mechanism (32).

[0076] In this embodiment, a captured image (31d) of the second surface (41b) can be obtained simply by changing the height of the imaging section (31a).

[0077] <7> In the cutting device (1) described in any one of <1> to <6> above, the imaging unit (31a) may acquire an image (31d) of a cutting mark (41c) used when cutting the object to be cut (4) into individual pieces.

[0078] In this embodiment, the imaging unit (31a) captures an image (31d) of the cutting mark (41c) used when cutting the object (4), thereby making it possible to accurately measure the height position of the cutting point on the second surface (41b) of the object (4). This makes it possible to form a groove (44) of a desired depth.

[0079] <8> In the cutting device (1) described in any one of <1> to <7> above, the imaging unit (31a) may acquire a block imaging image of a reference block (37) that serves as a reference height for calculating the height position of the second surface (41b).

[0080] In this embodiment, the height position of the cutting point on the second surface (41b) of the cutting object (4) can be measured as a relative value using the block captured image of the reference block (37) as a reference.

[0081] <9> The cutting device (1) described in any one of <1> to <8> above may further include a blade (11a) that forms a groove (44) on the second surface (41b) of the object (4) to be cut, and a spindle unit (13) that rotates the blade (11a). After adjusting the height of the blade (11a) based on the height position of the second surface (41b) calculated by the calculation unit (35), the blade (11a) may form the groove (44) on the second surface (41b).

[0082] In this embodiment, the height of the blade (11a) is adjusted based on the height position of the second surface (41b) calculated by the calculation unit (35), and then the blade (11a) forms a groove (44) on the second surface (41b), so that a groove (44) of a desired depth can be formed on the second surface (41b) of the object to be cut (4).

[0083] <10> A method for manufacturing a cut product (40) includes a groove forming step of forming a groove (44) in an object to be cut (4) using a cutting device (1) described in any one of <1> to <9> above, and a singulation step of cutting the object to be cut (4) with the groove (44) formed therein into a plurality of cut products (40).

[0084] According to this embodiment, it is possible to reliably manufacture a cut product (40) having a wettable flank type substrate (41).

[0085] The present invention can be used in a cutting device and a method for manufacturing a cut product.

[0086] 1: Cutting device 4: Package substrate (object to be cut) 11a: First blade (blade) 13: Spindle portion 22: Table (cutting table) 31: Imaging mechanism 31a: Camera (imaging portion) 31b: Lens 31d: Captured image 32: Height changing mechanism 33: Light source 34: Shielding member 35: Calculation portion 36: Half mirror (mirror) 37: CCS block (reference block) 40: Electronic component (cut product) 41: Substrate (d) 41a: First surface 41b: Second surface 41c: Cross mark (cutting mark) 42: Resin layer 44: Half-cut groove (groove)

Claims

1. A cutting device for forming grooves in a second surface of an object to be cut, the second surface being opposite to the first surface of a plate-shaped lead frame, the cutting device comprising: a cutting table on which the object to be cut can be placed; a light source for irradiating light onto the second surface side of the object to be cut placed on the cutting table; a shielding member disposed midway through the path of the light propagating from the light source to the object to be cut and for blocking part of the light emitted from the light source; an imaging mechanism for acquiring an image of the second surface side of the object to be cut; a height changing mechanism for changing the height of the imaging mechanism; and a calculation unit for performing analysis processing of the acquired image, wherein the imaging mechanism has: a lens disposed on the light path closer to the object to be cut than the shielding member and for focusing the light from the light source onto the second surface; and an imaging unit disposed on the opposite side of the object to the cutting table and capable of acquiring the image by receiving the light reflected by the object to be cut, the imaging unit acquiring the image at a plurality of different heights changed by the height changing mechanism, The calculation unit calculates the height position of the second surface based on a focus state of the shielding member in the plurality of captured images.

2. The cutting device according to claim 1, wherein the shielding member is a frame that shields the outer edge region of the light emitted from the light source.

3. The cutting device according to claim 1 or 2, wherein the calculation unit calculates a contrast ratio between the shielding member and a location adjacent to the shielding member in each of the plurality of captured images, and calculates the height position of the second surface based on the height of the imaging unit when the captured image with the highest contrast ratio among the plurality of calculated contrast ratios was acquired.

4. A cutting device according to any one of claims 1 to 3, wherein the shielding member is arranged movably between the light source and the object to be cut.

5. A cutting device according to any one of claims 1 to 4, wherein the heights of the light source and the shielding member are changed in conjunction with a change in the height of the imaging unit by the height change mechanism.

6. A cutting device as described in any one of claims 1 to 5, further comprising a mirror arranged between the shielding member and the lens in the path of the light, which reflects the light toward the second surface, wherein the height of the mirror is changed in conjunction with the change in height of the imaging unit by the height change mechanism.

7. A cutting device according to any one of claims 1 to 6, wherein the imaging unit acquires the captured image of a cutting mark used when cutting the object to be cut into individual pieces.

8. A cutting device according to any one of claims 1 to 7, wherein the imaging unit acquires a block image of a reference block that serves as a reference height for calculating the height position of the second surface.

9. A cutting device as described in any one of claims 1 to 8, further comprising a blade that forms the groove on the second surface of the object to be cut, and a spindle unit that rotates the blade, wherein the blade forms the groove on the second surface after adjusting the height of the blade based on the height position of the second surface calculated by the calculation unit.

10. A method for manufacturing cut products, comprising: a groove forming step of forming the groove in the cutting object using the cutting device described in any one of claims 1 to 9; and a singulation step of cutting the cutting object with the groove formed therein into a plurality of cut products.

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