JP7282450B2 - Package substrate processing method - Google Patents

Description

The present invention relates to a method of processing a package substrate by cutting the package substrate with a cutting blade, and a package substrate cut by the cutting blade.

A package substrate such as a QFN package (Quad For Non-Lead Package) substrate is formed by covering a plurality of device chips arranged on a base substrate with a resin sealing material (mold resin). By dividing the package substrate along the dividing lines (street), a plurality of package devices each including a device chip can be obtained.

A cutting device including, for example, a chuck table holding the package substrate and a cutting unit to which an annular cutting blade for cutting the package substrate is mounted is used for dividing the package substrate. The package substrate is cut by rotating the cutting blade to cut into the package substrate while the package substrate is held by the chuck table.

When dividing the package substrate, a method of cutting the package substrate in two stages may be used. Specifically, first, a cutting blade is cut into the package substrate to form a cutting groove whose depth is less than the thickness of the package substrate along the dividing line. Then, after performing a predetermined process on the package substrate on which the cut grooves are formed, the package substrate is cut for the second time by cutting the package substrate along the cut grooves with the cutting blade.

The details of the processing performed between the first cutting and the second cutting are determined according to the type of package substrate, processing conditions, and the like. Examples of this treatment include removal of burrs generated by the first cutting, plating of the inside of the cut groove, inspection of the device chip, and the like.

For example, electrodes connected to device chips may be formed on the division line of the package substrate. In this case, when the cutting blade is caused to cut along the dividing line, the electrode contacts the rotating cutting blade and is stretched, generating a whisker-like burr. The burr is desired to be removed because it causes a short circuit between electrodes and a bonding failure. Therefore, after the first cutting, a process of removing burrs by jetting water toward the cut area is sometimes performed (see, for example, Patent Document 1).

Further, Patent Document 2 discloses a technique of forming a cut groove in a package substrate and then forming a plating layer inside the cut groove using a metal material having solder wettability. Furthermore, Patent Document 3 discloses a method of inspecting a device chip by applying a probe to an electrode terminal formed by the first cutting, and then dividing the package substrate by the second cutting.

When cutting the package substrate with the cutting blade, it is necessary to detect the position of the dividing line to be cut with the cutting blade. Therefore, before the package substrate is cut, an image of the package substrate is picked up and alignment marks attached to the package substrate are detected to identify the coordinates of the planned division lines (see, for example, Patent Document 4). .

JP 2016-181569 A Japanese Patent Application Laid-Open No. 2008-112961 JP 2004-259936 A JP-A-2002-33295

Alignment marks are provided, for example, on the planned division lines of the package substrate, and are used as marks indicating the positions of the planned division lines. Here, when cutting the package substrate in two stages as described above, the alignment marks are detected during the first cutting and the second cutting, respectively, and the division line to be cut by the cutting blade is determined. Must be located.

However, when the cutting groove is formed along the line to be divided by the first cutting, the alignment mark is removed at the same time, and it is difficult to specify the position of the line to be divided by using the alignment mark as a reference during the second cutting. become unable. Moreover, even if the alignment mark is not completely removed and part of it remains, the shape of the remaining alignment mark is distorted by cutting. If this distorted alignment mark is used as a guide, the position of the line to be divided may not be specified accurately.

On the other hand, there is also a method of identifying the cutting area in the second cutting by using the cutting groove formed in the first cutting as a mark instead of the removed alignment mark. However, there are variations in the shape of the cut grooves formed by cutting with the cutting blade. Therefore, if the cutting groove is used as a mark, there is a possibility that the accuracy of detecting the position of the line to be divided may deteriorate.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to provide a package substrate processing method and a package substrate that enable highly accurate detection of the position of a region to be cut by a cutting blade.

According to one aspect of the present invention, there is provided a method for processing a package substrate for cutting, with a cutting blade, a package substrate partitioned into a plurality of regions by a plurality of division lines that intersect with each other, the method comprising: corresponding to the division lines; and preparing the package substrate provided with an alignment mark at a position that does not overlap a region to be cut by the first cutting blade when the package substrate is cut along the dividing line by the first cutting blade. a package substrate preparing step; a first detecting step of detecting the position of the dividing line to be cut by the first cutting blade based on the position of the alignment mark; and a position detected in the first detecting step. performing a first cutting step of cutting the package substrate with the first cutting blade along the planned division line to form a cutting groove having a depth less than the thickness of the package substrate; and the first cutting step. a processing step of subjecting the package substrate to a predetermined processing; and after performing the processing step, detecting the position of the cutting groove to be cut by the second cutting blade based on the position of the alignment mark. 2 detection step; and a second cutting step of cutting the package substrate by cutting the package substrate with the second cutting blade along the cutting groove whose position is detected in the second detection step. A method for processing a package substrate is provided. Preferably, the alignment marks are provided outside the plurality of regions.

In a method for processing a package substrate according to an aspect of the present invention, a package substrate is used that has an alignment mark that corresponds to the line to be divided and that is attached at a position that does not overlap the area to be cut by the cutting blade. Then, the package substrate is subjected to a first cutting step of forming cut grooves in the package substrate and a second cutting step of cutting the package substrate.

According to the above package substrate processing method, the alignment mark remains without being removed by cutting in the first cutting step. Then, in the second cutting step, the position of the region to be cut by the cutting blade can be detected with high accuracy using the remaining alignment marks.

1A is a plan view showing the package substrate, FIG. 1B is a bottom view showing the package substrate, and FIG. 1C is a front view showing the package substrate. It is a top view which expands and shows a part of package substrate. 4 is a plan view showing a package substrate supported by a frame; FIG. FIG. 4A is a front view showing the package substrate in the first detection step, and FIG. 4B is a diagram showing the first reference image. FIG. 5A is a front view showing the package substrate in the first cutting step, and FIG. 5B is a plan view showing an enlarged part of the package substrate after the first cutting step. It is a front view which shows a package substrate in a process step. FIG. 7A is a front view showing the package substrate in the second detection step, and FIG. 7B is a diagram showing a second reference image. FIG. 11 is a front view showing the package substrate in the second cutting step; FIG. 9A is a plan view showing a jig table, and FIG. 9B is a sectional view showing the jig table.

Hereinafter, this embodiment will be described with reference to the accompanying drawings. First, a configuration example of a package substrate according to this embodiment will be described. 1A is a plan view showing the package substrate 11, FIG. 1B is a bottom view showing the package substrate 11, and FIG. 1C is a front view showing the package substrate 11. FIG. The type, material, shape, structure, size, etc. of the package substrate 11 are not limited. For example, a CSP (Chip Size Package) substrate, a QFN package (Quad For Non-Lead Package) substrate, or the like can be used as the package substrate 11 .

The package substrate 11 includes a plate-like base substrate 13 having a front surface 13a and a rear surface 13b and formed in a rectangular shape in plan view. The base substrate 13 is made of metal such as 42 alloy (alloy of iron and nickel) or copper. The material, shape, structure, size, etc. of the base substrate 13 are not limited.

A plurality of device chips (not shown) including devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are arranged on the back surface 13b side of the base substrate 13 . There are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device chip. These device chips are covered and sealed with a resin layer (mold resin) 15 formed on the back surface 13 b side of the base substrate 13 .

As shown in FIG. 1A, the package substrate 11 is partitioned into a plurality of regions (device regions 11a) by a plurality of dividing lines (streets) 17 arranged in a grid pattern so as to cross each other. Each chip is arranged in this device region 11a. In addition, the package substrate 11 has an extra peripheral region 11b surrounding the plurality of device regions 11a.

By dividing the package substrate 11 along the dividing line 17, each device region 11a is separated to obtain a plurality of package devices each including a device chip sealed with resin. The division of the package substrate 11 is performed, for example, by cutting the package substrate 11 with an annular cutting blade.

A plurality of electrodes 19 made of metal such as copper are arranged along dividing lines 17 on the front surface 13 a side of the base substrate 13 . The electrode 19 is connected to a device chip arranged on the back surface 13b side of the base substrate 13 via a metal wire (not shown) or the like, and is exposed on the front surface 13a side of the base substrate 13 . After the package substrate 11 is divided into a plurality of package devices, the electrodes 19 function as connection electrodes when the package devices are mounted on another mounting substrate or the like.

A plurality of alignment marks 21 indicating the positions of the dividing lines 17 are provided on the front surface 13 a side of the base substrate 13 . This alignment mark 21 serves as a mark for alignment between the package substrate 11 and the cutting blade when cutting the package substrate 11 . FIG. 1A shows an example in which two pairs of alignment marks 21 are attached to each line to be divided 17 . Specifically, two alignment marks 21 are respectively attached to one end side and the other end side of one planned dividing line 17 .

The alignment mark 21 may be attached to the back surface 13b side of the base substrate 13, or may be attached to both the front surface 13a side and the back surface 13b side. Alternatively, the alignment marks 21 may be attached only to some of the planned division lines 17 . There is no limit to the number of alignment marks 21 attached to one dividing line 17 .

FIG. 2 is a plan view showing an enlarged part of the package substrate 11. As shown in FIG. FIG. 2 shows four sets of alignment marks 21 (21a, 21b, 21c, 21d) respectively corresponding to the four planned division lines 17 (17a, 17b, 17c, 17d). FIG. 2 also shows a region to be cut by the first cutting blade 14 (see FIG. 5A) when the package substrate 11 is cut along the dividing line 17 by the first cutting blade 14 (see FIG. 5A). The corresponding cutting area 11c is shown. A width W of the cutting area 11 c corresponds to the width of the first cutting blade 14 .

The pair of alignment marks 21 are provided at positions that sandwich the cutting region 11c in the width direction of the cutting region 11c and do not overlap the cutting region 11c. Therefore, even if the package substrate 11 is cut with the first cutting blade 14 in the first cutting step described later, the alignment mark 21 remains without being cut.

Device chips, wiring, and the like are arranged in the device region 11a, and if the alignment marks 21 are attached to the device region 11a, the characteristics of the device chip may be affected. Therefore, it is preferable that the alignment marks 21 are provided outside the plurality of device regions 11a. FIG. 1(A) shows an example in which a plurality of alignment marks 21 are respectively attached to outer peripheral surplus regions 11b positioned outside the plurality of device regions 11a.

In the method of processing a package substrate according to the present embodiment, first, the package substrate 11 with the alignment marks 21 is prepared (package substrate preparation step). There are no restrictions on the specific method of manufacturing the package substrate 11 or the method of attaching the alignment marks 21 . For example, when forming the electrodes 19, the same material as that of the electrodes 19 may be used to form an electrode pattern that becomes the alignment mark 21 in the outer peripheral surplus region 11b. Alternatively, the alignment mark 21 may be attached by coloring the peripheral surplus region 11b of the package substrate 11 .

Next, by cutting the package substrate 11 using a cutting machine, the package substrate 11 is divided into a plurality of package devices. When cutting the package substrate 11 with a cutting device, first, the package substrate 11 is supported by an annular frame. FIG. 3 is a plan view showing the package substrate 11 supported by the frame 25. FIG.

A circular tape 23 having a diameter capable of covering the entire package substrate 11 is adhered to the back side of the package substrate 11 (the side of the resin layer 15 (see FIG. 1B)). The tape 23 is a flexible film obtained by forming a rubber-based or acrylic-based adhesive layer (paste layer) on a resin base material such as polyolefin, polyvinyl chloride, or polyethylene terephthalate.

An annular frame 25 is attached to the outer periphery of the tape 23 . The frame 25 has a circular opening 25a with a diameter capable of accommodating the package substrate 11 therein. The package substrate 11 is supported by the frame 25 via the tape 23 while being arranged inside the opening 25a so that the surface side (surface 13a side of the base substrate 13) is exposed upward.

However, the tape 23 may be attached to the front surface side of the package substrate 11 (the front surface 13a side of the base substrate 13). In this case, the package substrate 11 is supported by the frame 25 with its rear surface side (resin layer 15 side) exposed upward. Also, a plurality of package substrates 11 may be attached to the tape 23 . In this case, a frame 25 having an opening 25a with a diameter capable of accommodating a plurality of package substrates 11 is used.

Note that the package substrate 11 does not necessarily have to be supported by the frame 25 . When the frame 25 is not used, for example, a rectangular tape having approximately the same size as the package substrate 11 is attached to the front side or the back side of the package substrate 11 . Also, when a jig table 30 (see FIGS. 9A and 9B), which will be described later, is used to hold the package substrate 11, the attachment of the tape to the package substrate 11 can be omitted.

The package substrate 11 supported by the frame 25 is transported to a cutting device and held by a chuck table provided in the cutting device. Then, the package substrate 11 is cut by a first cutting blade 14 (see FIG. 5A) and a second cutting blade 24 (see FIG. 8) to divide into a plurality of package devices.

When cutting the package substrate 11 with the first cutting blade 14, first, the position of the dividing line 17 to be cut with the first cutting blade 14 is detected based on the position of the alignment mark 21 (first detection step). . FIG. 4A is a front view showing the package substrate 11 in the first detection step.

The cutting device 2 shown in FIG. 4A includes a chuck table (holding table) 4 that holds the package substrate 11 . The chuck table 4 is connected to a rotation drive source (not shown) such as a motor, and this rotation drive source rotates the chuck table 4 around a rotation axis substantially parallel to the Z-axis direction (vertical direction, vertical direction). . Further, the chuck table 4 is connected to a moving mechanism (not shown), and this moving mechanism moves the chuck table 4 along the X-axis direction (first horizontal direction, processing feed direction).

The upper surface of the chuck table 4 is made of porous ceramics or the like, and constitutes a holding surface 4a for holding the package substrate 11 . The holding surface 4a is formed substantially parallel to the X-axis direction and the Y-axis direction (second horizontal direction, indexing feed direction), and through a suction path (not shown) provided inside the chuck table 4, etc. It is connected to a suction source (not shown) such as an ejector.

When the package substrate 11 is held by the chuck table 4, first, the package substrate 11 is placed on the chuck table 4 so that the back side (tape 23 side) of the package substrate 11 faces the holding surface 4a. A frame 25 (see FIG. 3) that supports the package substrate 11 is fixed by a plurality of clamps (not shown) provided around the chuck table 4 . When a negative pressure of a suction source is applied to the holding surface 4a in this state, the package substrate 11 is suction-held by the chuck table 4 via the tape 23. As shown in FIG.

An imaging unit (camera) 6 for imaging the package substrate 11 held by the chuck table 4 is provided above the chuck table 4 . The imaging unit 6 is connected to a control section 8 that controls the operation of each component of the cutting device 2 . The image of the package substrate 11 acquired by the imaging unit 6 is output to the control section 8, and the control section 8 performs predetermined image processing.

In the first detection step, first, the imaging unit 6 images the package substrate 11 held by the chuck table 4 . Based on the captured image, the position of the dividing line 17 to be cut by the first cutting blade 14 (see FIG. 5A) is detected in the first cutting step, which will be described later.

Specifically, part of the package substrate 11 is imaged by the imaging unit 6 , and an image (captured image) acquired by imaging is output to the control unit 8 . At this time, the image pickup unit 6 picks up an image of the package substrate 11, particularly in the vicinity of the region where the alignment mark 21 (see FIG. 1A and the like) is attached.

The control unit 8 also stores a first reference image (first template image) 10 having the same pattern as the region on which the alignment marks 21 are attached on the package substrate 11 . FIG. 4B is a diagram showing the first reference image 10. FIG. The first reference image 10 includes a pair of patterns 10a corresponding to a pair of alignment marks 21 (see FIG. 1A, etc.) provided on the package substrate 11. FIG.

The control unit 8 performs pattern matching between the captured image acquired by the imaging unit 6 and the first reference image 10 . Specifically, the captured image including the pair of alignment marks 21 and the first reference image 10 including the pair of patterns 10a are compared to determine whether or not they match.

When the captured image and the first reference image 10 match, the control unit 8 calculates the coordinates of the alignment mark 21 based on the positional relationship between the chuck table 4 and the imaging unit 6 when the captured image was obtained. do. Thereby, the position of the alignment mark 21 provided on the package substrate 11 is specified.

Information indicating the positional relationship between the alignment marks 21 and the planned division lines 17 is stored in advance in the control unit 8 . Specifically, the positions of the alignment marks 21 and the positions of the division lines 17 corresponding to the alignment marks 21 are stored in association with each other. When the position of the alignment mark 21 is obtained, the control unit 8 refers to the information and specifies the position of the planned division line 17 corresponding to the alignment mark 21 .

Thus, the position of the line to be divided 17 is detected based on the position of the alignment mark 21 . In addition, in the first detection step, the positions of all the planned division lines 17 may be detected, or only the positions of some of the planned division lines 17 may be detected.

For example, when using the package substrate 11 shown in FIG. 1A, only the positions of the planned division lines 17 closest to the four sides of the package substrate 11 may be detected. Further, for each of three blocks surrounded by the outer peripheral surplus region 11b (the region including the 4×4 device regions 11a in FIG. 1A), four planned division lines 17 closest to the four sides of each block are drawn. Only the position may be detected. In this case, the positions of the other planned division lines 17 are calculated by the control unit 8 based on the positions of the planned division lines 17 whose positions have been detected.

Next, the package substrate 11 is cut with the first cutting blade 14 along the dividing line 17 whose position is detected in the first detection step (first cutting step). FIG. 5A is a front view showing the package substrate 11 in the first cutting step.

A first cutting unit 12 to which a first cutting blade 14 is attached is arranged above the chuck table 4 . The first cutting unit 12 has a spindle (not shown) whose axis is substantially parallel to the holding surface 4a of the chuck table 4, and an annular first cutting blade 14 is attached to the tip of the spindle. be. The first cutting blade 14 is formed by fixing abrasive grains made of diamond or the like with a bond material. A metal bond, a resin bond, a vitrified bond, or the like is used as the bond material.

The spindle provided in the first cutting unit 12 is connected to a rotational drive source (not shown) such as a motor, and the first cutting blade 14 attached to the spindle is rotated by force transmitted from the rotational drive source. The first cutting unit 12 is also connected to a moving mechanism (not shown), which controls the position of the first cutting unit 12 in the Y-axis direction and the Z-axis direction.

In the first cutting step, first, the chuck table 4 is rotated to align the length direction of one scheduled division line 17 with the processing feed direction (X-axis direction) of the cutting device 2 . Further, the height of the first cutting unit 12 is adjusted so that the lower end of the first cutting blade 14 is arranged below the surface 13a of the base substrate 13 and above the lower surface of the resin layer 15 (the upper surface of the tape 23). adjust the depth. Further, the position of the first cutting unit 12 in the index feed direction (Y-axis direction) is adjusted so that the first cutting blade 14 is arranged on the extension line of the one planned dividing line 17 .

Thereafter, while rotating the first cutting blade 14, the chuck table 4 is moved in the processing feed direction (X-axis direction). As a result, the chuck table 4 and the first cutting unit 12 move relative to each other, and the first cutting blade 14 cuts into the package substrate 11 along the dividing line 17 . As a result, the cutting area 11 c (see FIG. 2) is cut by the first cutting blade 14 .

Here, the alignment between the chuck table 4 and the first cutting unit 12 is based on the position of the planned dividing line 17 detected in the first detection step, and the first cutting blade 14 is positioned at a desired position on the planned dividing line 17. It is done so as to cut into For example, the chuck table 4 and the first cutting unit 12 are arranged so that the center of the first cutting blade 14 in the width direction moves along the center of the line to be divided 17 in the width direction. As a result, the first cutting blade 14 cuts the package substrate 11 along the center of the dividing line 17 in the width direction.

Further, for example, the first cutting blade 14 cuts the package substrate 11 to a depth that cuts the base substrate 13 and does not cut the resin layer 15 . As a result, cut grooves 11 d (see FIG. 5B) whose depth is less than the thickness of the package substrate 11 are formed along the dividing lines 17 in the package substrate 11 .

After that, the same procedure is repeated to form cut grooves 11 d along other planned division lines 17 . As a result, a plurality of cut grooves 11d are formed in a grid pattern on the front surface side of the package substrate 11 (on the front surface 13a side of the base substrate 13). Hereinafter, the package substrate 11 in which the cut groove 11d is formed is also referred to as a half-cut package substrate 11. As shown in FIG.

FIG. 5B is a plan view showing an enlarged part of the package substrate 11 after the first cutting step. In the first cutting step, the cutting region 11c (see FIG. 2) is cut by the first cutting blade 14 to form the cutting groove 11d. Since the cut groove 11d is formed between the pair of alignment marks 21, the alignment mark 21 is not cut by the first cutting blade 14 and remains after the first cutting step.

Next, a predetermined process is performed on the package substrate on which the cut groove 11d is formed (processing step). The processing performed in the processing step is not limited as long as it is processing that should be performed on the package substrate 11 in a half-cut state. For example, in the processing step, processing is performed to remove burrs caused by performing the first cutting step.

In the first cutting step, when the package substrate 11 is cut along the dividing line 17 with the first cutting blade 14, the electrodes 19 arranged along the dividing line 17 come into contact with the rotating first cutting blade 14 and are pulled. It is elongated and may produce whisker-like burrs. Since this burr causes a short circuit between the electrodes 19 and a bonding failure, it is preferable to remove the burr. Therefore, a process for removing burrs remaining near the cut groove 11d is performed by injecting a fluid such as water toward the cut groove 11d.

FIG. 6 is a front view showing the package substrate 11 in the processing steps. A nozzle 16 is arranged above the chuck table 4 . The nozzle 16 is connected to a fluid supply source (not shown) and injects a fluid 18 such as water at a predetermined pressure toward the package substrate 11 held by the chuck table 4 . Further, the nozzle 16 is connected to a moving mechanism (not shown), and the position of the nozzle 16 is controlled by this moving mechanism.

By ejecting the fluid 18 from the nozzle 16 while relatively moving the chuck table 4 and the nozzle 16, the fluid 18 is ejected along the cutting groove 11d. As a result, the burrs remaining in the vicinity of the cutting groove 11d are blown away by the fluid 18 and removed.

Note that when the fluid 18 is sprayed onto the package substrate 11 after the package substrate 11 is divided into a plurality of individual pieces (package devices), the pressure of the fluid 18 scatters the individual pieces and causes exposure between adjacent pieces. Breakage of the tape 23 may occur. Therefore, it is preferable to spray the fluid 18 onto the half-cut package substrate 11 as shown in FIG.

As described above, when the cutting device 2 having the nozzle 16 is used to remove burrs, the processing step can be performed while the package substrate 11 is held by the chuck table 4 after the first cutting step. As a result, transportation of the package substrate 11 can be omitted, and the process can be simplified.

Note that the processing performed in the processing step is not limited to removing burrs. For example, in the processing step, the electrical characteristics of the device chip connected to the electrode 19 may be inspected by applying a probe to the electrode 19 (see FIG. 5B) divided by the first cutting step.

Further, in the processing step, the inside of the cut groove 11d may be plated. Electrodes 19 shown in FIG. 5B are formed of metal such as copper, and are connected to other terminals (connection terminals of a mounting substrate, etc.) via solder or the like in a later process. However, when the cut groove 11d is formed, the electrode 19 is exposed inside the cut groove 11d, and after a certain period of time has passed in this state, the electrode 19 is oxidized and the solder wettability is lowered. Therefore, in the treatment step, the electrode 19 may be plated and the surface of the electrode 19 may be covered with a metal thin film made of tin or the like. As a result, it is possible to suppress a decrease in the strength of the solder joint.

The depth of the cutting groove 11d formed in the first cutting step (cutting depth of the first cutting blade 14) is appropriately set according to the details of the processing performed in the processing step. For example, when burrs are removed by the fluid 18 in the processing step (see FIG. 6), the electrode 19 is cut and the strength of the package substrate 11 is above a certain level (the package substrate 11 is split due to the injection of the fluid 18). The depth of the cutting groove 11d is set so as to be maintained at the level of

In addition, although an example in which the cutting device 2 includes the components (the nozzle 16 in FIG. 6, etc.) used in the processing steps has been described above, the cutting device 2 may not include the components used in the processing steps. In this case, the processing steps are performed using a device separate from the cutting device 2 .

Next, the position of the cutting groove 11d to be cut by the second cutting blade 24 is detected based on the position of the alignment mark 21 (second detection step). FIG. 7A is a front view showing the package substrate 11 in the second detection step.

In the second detection step, first, the imaging unit 6 images the package substrate 11 held by the chuck table 4 . Then, the position of the cut groove 11d to be cut by the second cutting blade 24 (see FIG. 8) is detected based on the image obtained by imaging.

A method for detecting the position of the cutting groove 11d is the same as the method for detecting the position of the planned division line 17 in the first detection step. However, for detecting the position of the cut groove 11d, a second reference image (second template image) having the same pattern as the region on which the alignment mark 21 is attached in the package substrate 11 after the formation of the cut groove 11d. 20 is used.

FIG. 7B is a diagram showing the second reference image 20. As shown in FIG. The second reference image 20 is stored in the control section 8 . The second reference image 20 includes a pair of first patterns 20a corresponding to a pair of alignment marks 21 (see FIG. 5B, etc.) provided on the package substrate 11, and cutting grooves formed on the package substrate 11. A second pattern 20b corresponding to 11d is included.

The control unit 8 performs pattern matching between the captured image acquired by the imaging unit 6 and the second reference image 20 . Specifically, the captured image including the pair of alignment marks 21 sandwiching the cutting groove 11d is compared with the second reference image 20 including the pair of first patterns 20a sandwiching the second pattern 20b, and the two match. It is determined whether or not Then, when the captured image and the second reference image 20 match, the control unit 8 calculates the coordinates of the cutting groove 11d based on the positional relationship between the chuck table 4 and the imaging unit 6 when the captured image was obtained. identify.

Here, the alignment mark 21 is not cut by the first cutting blade 14 in the first cutting step (see FIG. 5B), and the shape of the alignment mark 21 is not distorted. By using this alignment mark 21, the position of the cutting groove 11d can be detected with high accuracy.

In addition, in the second detection step, the positions of all the cutting grooves 11d may be detected in the same manner as the detection of the dividing line 17 in the first detection step, or only the positions of some of the cutting grooves 11d may be detected. may When detecting only the positions of some of the cut grooves 11d, the positions of the other cut grooves 11d are calculated by the control unit 8 based on the positions of the cut grooves 11d whose positions have been detected.

Next, the package substrate 11 is cut with the second cutting blade 24 along the cutting groove 11d whose position has been detected in the second detection step, thereby cutting the package substrate 11 (second cutting step). FIG. 8 is a front view showing the package substrate 11 in the second cutting step.

A second cutting unit 22 to which a second cutting blade 24 is attached is arranged above the chuck table 4 . The structure, function, etc. of the second cutting unit 22 are the same as those of the first cutting unit 12 (see FIG. 5A). Also, the material and the like of the second cutting blade 24 are the same as those of the first cutting blade 14 .

In the second cutting step, first, the chuck table 4 is rotated to align the length direction of one cutting groove 11d with the feed direction of the cutting device 2 (X-axis direction). Further, the second cutting blade 24 is positioned below the lower surface of the resin layer 15 (the upper surface of the tape 23) and above the lower surface of the tape 23 (the holding surface 4a). Adjust the height of the unit 22. Further, the position of the second cutting unit 22 in the index feed direction (Y-axis direction) is adjusted so that the second cutting blade 24 is arranged on the extension line of the one cutting groove 11d.

After that, the chuck table 4 is moved in the processing feed direction (X-axis direction) while rotating the second cutting blade 24 . As a result, the chuck table 4 and the second cutting unit 22 move relative to each other, and the second cutting blade 24 cuts into the package substrate 11 along the cutting groove 11d. As a result, the package substrate 11 is cut along the cutting groove 11d.

Here, the alignment between the chuck table 4 and the second cutting unit 22 is performed so that the second cutting blade 24 cuts into the bottom of the cutting groove 11d based on the position of the cutting groove 11d detected in the second detection step. will be As a result, a cut (kerf) extending from the bottom of the cut groove 11d to the back surface of the package substrate (the bottom surface of the resin layer 15) is formed, and the package substrate 11 is divided.

In addition, in the second cutting step, a second cutting blade 24 having a width smaller than that of the first cutting blade 14 may be used. In this case, for example, the second cutting blade 24 is positioned so as to pass inside the cutting groove 11d. This avoids contact between the electrode 19 (see FIG. 5B, etc.) exposed inside the cutting groove 11d and the second cutting blade 24, and suppresses the occurrence of burrs. Moreover, even if a plating layer is formed on the surface of the electrode 19 in the treatment step, the plating layer is not removed because the second cutting blade 24 and the plating layer do not come into contact with each other.

After that, the same procedure is repeated to cut the package substrate 11 along another cut groove 11d. As a result, the package substrate 11 is cut along all the dividing lines 17 to divide into a plurality of package devices each having a device chip.

As described above, in the method for processing a package substrate according to the present embodiment, the package substrate 11 having the alignment mark 21 provided at a position corresponding to the dividing line 17 and not overlapping the area to be cut by the cutting blade. Used. Then, the package substrate 11 is subjected to a first cutting step of forming cut grooves in the package substrate 11 and a second cutting step of cutting the package substrate 11 .

According to the above package substrate processing method, the alignment mark 21 remains without being removed by cutting in the first cutting step. Then, in the second cutting step, using the remaining alignment marks 21, the position of the region to be cut by the cutting blade can be detected with high accuracy.

In the above description, the cutting device 2 includes two sets of cutting units (the first cutting unit 12 and the second cutting unit 22). good. In this case, after the first cutting blade 14 is attached to the cutting unit and the first cutting step is performed, the first cutting blade 14 is replaced with the second cutting blade 24 and the second cutting step is performed. However, if the second cutting blade 24 is identical to the first cutting blade 14, replacement is not required.

Moreover, although the example in which the package substrate 11 is held by the chuck table 4 via the tape 23 has been described above, the method for holding the package substrate 11 is not limited. For example, the jig table 30 can be used as holding means for holding the package substrate 11 . 9A is a plan view showing the jig table 30, and FIG. 9B is a sectional view showing the jig table 30. FIG.

The jig table 30 includes a jig base 32 that is rectangular in plan view. This jig base 32 is provided in the cutting device 2 in place of the chuck table 4 (see FIG. 4A, etc.). The jig base 32 is connected to a rotation drive source (not shown) such as a motor, and this rotation drive source rotates the jig base 32 around a rotation axis substantially parallel to the vertical direction. Further, the jig base 32 is connected to a moving mechanism (not shown), and this moving mechanism moves the jig base 32 along the processing feed direction.

A holding member 34 formed in a rectangular shape in plan view corresponding to the shape of the package substrate 11 is detachably attached to the upper surface 32 a of the jig base 32 . The upper surface of the holding member 34 constitutes a holding surface 34 a that holds the package substrate 11 .

A groove 34c corresponding to the dividing line 17 of the package substrate 11 is formed on the side of the holding surface 34a of the holding member 34, and the upper end of the groove 34c opens at the holding surface 34a. The grooves 34c divide the holding surface 34a into a plurality of regions corresponding to the device regions 11a of the package substrate 11 (see FIG. 1A).

A suction hole 34d penetrating vertically through the holding member 34 is formed in each region partitioned by the groove 34c. As shown in FIG. 9B, when the holding member 34 is arranged on the upper surface 32a of the jig base 32, each suction hole 34d is formed in the central portion of the jig base 32 on the upper surface 32a side. connected to

The first flow path 32b is connected to a suction source 38 via a valve 36a. When the package substrate 11 is placed on the holding surface 34a of the holding member 34 and the dividing line 17 of the package substrate 11 is superimposed on the groove 34c, the valve 36a is opened. be done.

A second flow path 32 c for mounting the holding member 34 on the jig base 32 is formed in the outer peripheral portion of the jig base 32 . This second flow path 32c is connected to a suction source 38 via a valve 36b. The holding member 34 is fixed to the upper surface 32a of the jig base 32 when the lower surface 34b of the holding member 34 is brought into contact with the upper surface 32a of the jig base 32 and the valve 36b is opened.

The method for processing a package substrate according to the present embodiment can also be performed while the package substrate 11 is held by the jig table 30 . When the package substrate 11 is held by the jig table 30 , the dividing lines 17 of the package substrate 11 are arranged at positions overlapping the grooves 34 c of the holding member 34 . Therefore, when cutting the package substrate 11 in the second cutting step, the lower end of the second cutting blade 24 is inserted into the groove 34c. Thereby, contact between the second cutting blade 24 and the holding member 34 is avoided, and damage to the second cutting blade 24 and the holding member 34 is prevented.

In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

REFERENCE SIGNS LIST 11 Package substrate 11a Device region 11b Surplus peripheral region 11c Cutting region 11d Cutting groove 13 Base substrate 13a Front surface 13b Back surface 15 Resin layer (mold resin)
17 Planned division line (street)
17a, 17b, 17c, 17d Line to be divided (street)
19 electrode 21 alignment mark 21a, 21b, 21c, 21d alignment mark 23 tape 25 frame 25a opening 2 cutting device 4 chuck table (holding table)
4a holding surface 6 imaging unit (camera)
8 control unit 10 first reference image (first template image)
10a pattern 12 first cutting unit 14 first cutting blade 16 nozzle 18 fluid 20 second reference image (second template image)
20a first pattern 20b second pattern 22 second cutting unit 24 second cutting blade 30 jig table 32 jig base 32a upper surface 32b first flow path 32c second flow path 34 holding member 34a holding surface 34b lower surface 34c groove 34d suction Holes 36a, 36b Valve 38 Suction source

Claims (2)

A package substrate processing method for cutting a package substrate divided into a plurality of regions by a plurality of dividing lines that intersect each other with a cutting blade,
An alignment mark provided at a position corresponding to the planned division line and not overlapping the area cut by the first cutting blade when the package substrate is cut along the planned division line by the first cutting blade. a package substrate preparation step of preparing the package substrate comprising
a first detection step of detecting the position of the planned dividing line to be cut by the first cutting blade based on the position of the alignment mark;
cutting the package substrate with the first cutting blade along the dividing line whose position is detected in the first detecting step to form a cutting groove having a depth less than the thickness of the package substrate; a cutting step;
a processing step of performing a predetermined processing on the package substrate after performing the first cutting step;
a second detection step of detecting the position of the cutting groove to be cut by the second cutting blade based on the position of the alignment mark after performing the processing step;
a second cutting step of cutting the package substrate by cutting the package substrate with the second cutting blade along the cutting groove whose position is detected in the second detection step. A method of processing a package substrate. 2. The method of processing a package substrate according to claim 1, wherein the alignment marks are provided outside the plurality of regions.

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