JP2016004831A - Package substrate cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cutting a package substrate, having improved certainty of cutting and suppressed abrasion of a cut blade.SOLUTION: The method includes: a tape adhesion step which adheres a dicing tape (31) on the metal frame body (13) side which comes to a rear face of a package substrate (11); a retention step which holds the package substrate having an adhered dicing tape with a retention surface (4a) of a chuck table (4) through the dicing tape; and a cutting step which positions a cut blade (8) at a height at which the dicing tape is to be cut, and causes relative movement between the chuck table for holding the package substrate and the cut blade, to cut and divide the package with the cut blade. In the cutting step, the cut blade for cutting the package substrate is configured to cut into the package substrate while rotating from the rear face of the package substrate to the surface thereof.

Description

  The present invention relates to a cutting method in which a package substrate in which a plurality of device chips are arranged on a metal frame and sealed with a resin or the like is cut with a cutting blade.

  A semiconductor package such as a QFN (Quad Flat Non-leaded Package) is, for example, a device in which a plurality of device chips are arranged on a metal frame and sealed with a resin or the like, and the formed package substrate is cut with a cutting blade. It is obtained by dividing each chip (for example, see Patent Document 1).

  However, even if a cutting blade that is rotated is cut into the package substrate, the ductile metal frame is plastically stretched and the package substrate cannot be cut appropriately. This tendency is particularly remarkable when a region where the metal frame is exposed is cut.

  Therefore, a cutting blade (for example, a resin-based cutting blade) that is easy to wear out and exposes abrasive grains is used to suppress clogging by metal, and the cutting feed rate is reduced to increase cutting reliability. A method is being considered. In this cutting method, the cutting blade is rotated and cut in the direction from the front surface to the back surface of the package substrate (down cut).

JP 2006-261525 A

  However, the above-described cutting method has a problem that it takes a long time to complete the cutting and the amount of wear of the cutting blade is large. In addition, since the elongated metal protrusion (burr) is likely to extend toward the dicing tape, the cutting blade is likely to be clogged as if the protrusion is involved, and reliable cutting becomes difficult. . In this case, cooling may be insufficient and the cutting blade may be abnormally worn.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method for cutting a package substrate that increases the certainty of cutting and suppresses wear of a cutting blade.

  According to the present invention, a metal frame including a device region in which devices are arranged in a plurality of regions divided by a plurality of intersecting scheduled lines, and an outer peripheral surplus region surrounding the device region, and the metal A package substrate comprising: a plurality of devices disposed in the device region on the surface of the frame; and a resin sealing portion in which the device is sealed with a resin on the surface of the metal frame excluding the outer peripheral surplus region A cutting method of a package substrate that is divided by cutting a tape, a tape attaching step of attaching a dicing tape to the metal frame side that is the back surface of the package substrate, and a package substrate on which the dicing tape is attached, A holding step for holding the holding surface of the chuck table via the dicing tape, and positioning the cutting blade at a height for cutting into the dicing tape. A cutting step of cutting and dividing the package substrate with the cutting blade by relatively moving the chuck table holding the package substrate and the cutting blade, and the cutting blade for cutting the package substrate in the cutting step However, there is provided a method for cutting a package substrate, wherein the package substrate is cut into the package substrate while rotating from the back surface to the front surface of the package substrate.

  In the present invention, the metal frame is preferably composed of 42 alloy or copper.

  In the cutting method of the package substrate according to the present invention, in the cutting step of cutting the package substrate having the dicing tape attached to the metal frame body side, the cutting blade rotated in the direction from the back surface to the front surface of the package substrate is used as the package substrate. Therefore, the metal protrusion (burr) does not extend toward the dicing tape. Thereby, the package substrate can be reliably cut.

  Further, since heat generation due to the cutting blade clogged with the generated protrusions is suppressed, cooling of the cutting blade is not hindered. That is, abnormal wear of the cutting blade due to insufficient cooling can be suppressed. As described above, according to the present invention, it is possible to provide a method for cutting a package substrate that increases the certainty of cutting and suppresses wear of the cutting blade.

1A is a plan view schematically showing the package substrate, FIG. 1B is a bottom view schematically showing the package substrate, and FIG. 1C is a schematic view of the package substrate. FIG. It is a partial cross section side view which shows a holding step and a cutting step typically.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The package substrate cutting method according to the present embodiment includes a tape attaching step, a holding step (see FIG. 2), and a cutting step (see FIG. 2).

  In the tape attaching step, a dicing tape is attached to the back side of the package substrate. In the holding step, the back side of the package substrate to which the dicing tape is attached is held by the chuck table.

  In the cutting step, a cutting blade rotated in a direction from the back surface to the front surface of the package substrate is cut into the package substrate and cut. Hereinafter, the cutting method of the package substrate according to the present embodiment will be described in detail.

  FIG. 1A is a plan view schematically showing a package substrate cut by the cutting method of the present embodiment, and FIG. 1B is a bottom view schematically showing the package substrate. (C) is a side view schematically showing a package substrate. As shown in FIGS. 1A and 1B, the package substrate 11 includes a metal frame 13 formed in a substantially rectangular shape in plan view.

  The metal frame 13 is made of, for example, a metal such as 42 alloy (an alloy of iron and nickel) or copper, and includes a plurality of device regions 15 (here, three device regions 15) and each device region. 15 and an outer peripheral surplus area 17 surrounding 15.

  As shown in FIG. 1A, each device region 15 is further divided into a plurality of regions (here, 16 regions) by a plurality of division planned lines (streets) 19 intersecting with each other. Are provided with a device (device chip) 21 such as an IC or LED.

  Further, on the surface 13a side of the metal frame 13, a resin sealing portion 23 is formed by sealing a plurality of devices 21 with resin. As shown in FIG. 1C, the resin sealing portion 23 is formed with a predetermined thickness and protrudes from the surface 13 a of the metal frame 13. The resin sealing portion 23 covers the entire device region 15.

  As shown in FIG. 1B, a plurality of stages 25 corresponding to each device 21 are provided on the back surface 13 b side of the metal frame 13. A plurality of electrode pads 27 are formed around each stage 25.

  For example, the package substrate 11 is formed by placing the device 21 on each stage 25 from the surface 13a side of the metal frame 13, connecting the electrode of the device 19 and the electrode pad 27 with a metal wire (not shown), etc. It is formed by providing the sealing portion 23.

  In the package substrate cutting method according to this embodiment, first, a tape adhering step of adhering a dicing tape to the back side of the package substrate 11 described above is performed. In this tape sticking step, the back surface 13b of the metal frame 13 corresponding to the back surface of the package substrate 11 is brought into close contact with the bonding surface of the dicing tape 31 having a larger diameter than the package substrate 11 (see FIG. 2).

  Thereby, the dicing tape 31 is attached to the back side of the package substrate 11. An annular frame 33 is fixed to the outer peripheral portion of the dicing tape 31. Thus, the package substrate 11 is supported by the annular frame 33 via the dicing tape 31. However, the shapes of the dicing tape 31 and the frame 33 are not particularly limited.

  After the tape attaching step, a holding step for holding the back side of the package substrate 11 to which the dicing tape 31 is attached with a chuck table is performed. FIG. 2 is a partial cross-sectional side view schematically showing a holding step and a cutting step performed after the holding step.

  The holding step and the cutting step are performed by, for example, the cutting device 2 shown in FIG. The cutting device 2 includes a chuck table 4 that holds the package substrate 11 by suction. The chuck table 4 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis extending in the vertical direction. A machining feed mechanism (not shown) is provided below the chuck table 4, and the chuck table 4 is moved in the machining feed direction by the machining feed mechanism.

  The upper surface of the chuck table 4 is a holding surface 4 a that holds the package substrate 11 by suction. A negative pressure of a suction source acts on the holding surface 4a through a flow path formed inside the chuck table 4, and a suction force for sucking the package substrate 11 is generated. Around the chuck table 4, a plurality of clamps 6 for holding the annular frame 33 are provided.

  A circular cutting blade 8 for cutting the package substrate 11 is disposed above the chuck table 4. The cutting blade 8 is mounted on one end side of a spindle (not shown) that rotates about an axis extending in the horizontal direction. A motor (not shown) is connected to the other end side of the spindle, and the cutting blade 8 mounted on the spindle rotates with the rotational force of this motor.

  The cutting blade 8 and the spindle are supported by an elevating mechanism (not shown) and move (elevate) in the vertical direction. Further, an index feed mechanism (not shown) is provided below the elevating mechanism, and the cutting blade 8 and the spindle are moved in the index feed direction by the index feed mechanism.

  In the holding step, the dicing tape 31 adhered to the back surface side of the package substrate 11 is brought into contact with the holding surface 4a of the chuck table 4 to apply a negative pressure of the suction source. As a result, the package substrate 11 is sucked and held on the chuck table 4 via the dicing tape 31. The annular frame 33 is fixed with a plurality of clamps 6.

  After the holding step, a cutting step of cutting the package substrate 11 by cutting the rotated cutting blade 8 is performed. In the cutting step, first, the chuck table 4 is moved and rotated, and the cutting blade 8 is positioned at the cutting start position of an arbitrary division planned line 19. In the present embodiment, the cutting blade 8 is positioned at a cutting start position set in an area outside the package substrate 11.

  Next, the lower end of the rotated cutting blade 8 is positioned lower than the interface between the package substrate 11 and the dicing tape 31, and the chuck table 4 is moved in a direction parallel to the division line 19 to be processed (processing feed). ) The cutting blade 8 is rotated in the direction from the back surface 13b to the front surface 13a of the metal frame 13 (the direction from the back surface to the front surface of the package substrate 11) (upcut).

  That is, the cutting blade 8 is rotated in the direction from the back surface 13b of the metal frame 13 toward the front surface 13a, and the chuck table 4 and the cutting blade 8 are relatively moved to cut the cutting blade 8 into the package substrate 11. .

  As described above, the lower end of the cutting blade 8 is positioned lower than the interface between the package substrate 11 and the dicing tape 31. Thereby, the cutting blade 8 is cut to the dicing tape 31, and the package substrate 11 can be completely cut along the division planned line 19 to be processed (full cut).

  In the cutting step of the present embodiment, the cutting blade 8 is rotated in the direction from the back surface 13b to the front surface 13a of the metal frame 13, so that the metal protrusions extended from the metal frame 13 (Burr) does not extend toward the dicing tape 31. Thereby, the package substrate 11 can be cut reliably.

  Furthermore, in the cutting step of the present embodiment, heat generation due to the cutting blade clogged with the generated projections is suppressed, so that cooling of the cutting blade 8 is not hindered. That is, abnormal wear of the cutting blade 8 due to insufficient cooling can be suppressed. When the above operation is repeated and the package substrate 11 is divided along all the division lines 19, the cutting step ends.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above-described embodiment, the package substrate 11 including the metal frame 13 made of a metal such as 42 alloy or copper is cut. However, when the present invention is used to cut another package substrate, a metal plate, or the like. You may use for.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 11 Package board 13 Metal frame 13a Front surface 13b Back surface 15 Device area | region 17 Peripheral surplus area | region 19 Line to be divided (street)
21 devices (device chips)
DESCRIPTION OF SYMBOLS 23 Resin sealing part 25 Stage 27 Electrode pad 31 Dicing tape 33 Frame 2 Cutting device 4 Chuck table 4a Holding surface 6 Clamp 8 Cutting blade

Claims (2)

A metal frame including a device region in which devices are arranged in a plurality of regions partitioned by a plurality of intersecting scheduled lines, and an outer peripheral surplus region surrounding the device region, and the surface of the metal frame A package substrate comprising a plurality of devices arranged in a device region and a resin sealing portion in which the device is sealed with resin on the surface of the metal frame excluding the outer peripheral surplus region is cut and divided. A method of cutting a package substrate,
A tape adhering step for adhering a dicing tape to the metal frame side to be the back surface of the package substrate;
A holding step of holding the package substrate to which the dicing tape is attached on the holding surface of the chuck table via the dicing tape;
A cutting step in which the cutting blade is positioned at a height at which the cutting blade is cut into the dicing tape, and the chuck table for holding the package substrate and the cutting blade are moved relative to each other to cut and divide the package substrate with the cutting blade. ,
In the cutting step, the cutting blade for cutting the package substrate cuts into the package substrate while rotating from the back surface to the front surface of the package substrate.   2. The package substrate cutting method according to claim 1, wherein the metal frame is made of 42 alloy or copper.