TW201628776A - Grinding method of package substrate - Google Patents

Abstract

An objective of the present invention is to provide a grinding method of a package substrate that can thinning the seal resin layer of the package substrate to the desired thickness by utilizing a cutting device even without the grinding device. The grinding method of a package substrate is to utilize a cutting device including the first cutting method having the first flat grinding stone that is a disc shape and the second cutting method having the second flat grinding stone to grind the seal resin layer of the package substrate, which seals the back sides of the plurality of elements with resin, to the desired thickness. The property of the method comprises: a protection component adhesion step, adhering the surface side of the package substrate on the protecting element that is integrated with the ring frame; a hold step, attracting and holding the surface side of package substrate, where the protecting element is adhered; a first grinding step, making the first flat grinding stone contact with the seal resin layer at the back side of the package substrate, and making the first flat grinding stone and the package substrate relatively move in the grinding progress direction to grind the seal resin layer of the package substrate to the first thickness after implementing the hold step; and the second grinding step, making the second flat grinding stone contact with the seal resin layer at the back side of the package substrate, and making the second flat grinding stone and the package substrate relatively move in the grinding progress direction to fine grind the seal resin layer of the package substrate to the desired thickness after implementing the first grinding step.

Description

Grinding method of package substrate Field of invention

The present invention relates to a method of grinding a package substrate which can grind a sealing resin layer of a package substrate to a desired thickness.

Background of the invention

The surface of each of the plurality of elements having the plurality of electrodes is disposed opposite to the electrode substrate (lead frame) and disposed at a predetermined interval, and the back surface of the element disposed on the electrode substrate is sealed with a resin (Chip Size) A package substrate such as a package or a QFN (Quad Flat Non-leaded Package) is divided into individual package components by a cutting device, and the package components that are divided are widely used in various electronic devices such as mobile phones and personal computers.

In recent years, with the miniaturization and weight reduction of electronic devices such as mobile phones and personal computers, individual package components have also become smaller and lighter. As a technique for achieving miniaturization and weight reduction, a technique is known in which a sealing resin on a back surface of a package substrate is ground to a desired thickness before the package substrate is divided into individual package elements, and then divided into a cutting device by a cutting device. Each of the packaged components (see, for example, Japanese Patent Laid-Open No. 2011-181641 and Japanese Patent Laid-Open No. Hei No. 2014-015490).

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2011-181641

Patent Document 2: Japanese Patent Laid-Open Publication No. 2014-015490

Summary of invention

However, in the methods disclosed in Patent Document 1 and Patent Document 2, since a grinding device for grinding the back surface of the package substrate before dividing the package substrate into individual package members is required, there is a problem that it is not economical.

The present invention has been made in view of the above, and its main object is to provide a grinding method for thinning a sealing resin layer of a package substrate to a desired thickness by using one cutting device without a grinding device. .

According to the present invention, there is provided a method of grinding a package substrate, which comprises using a first cutting means having a disk-shaped first flat grinding stone attached to a tip end of a first rotating shaft, and having a front end mounted on a second rotating shaft In the cutting device of the second cutting means of the disk-shaped second flat grinding stone, the sealing resin layer of the package substrate is ground to a desired thickness, and the package substrate is a plurality of elements having a plurality of electrodes. The surface faces the electrode substrate, and the plurality of elements are disposed on the electrode substrate at a predetermined interval, and has a sealing resin layer that is resin-sealed to the back surface of the plurality of elements of the electrode substrate, the seal The method for grinding a substrate comprises: a step of adhering a protective member, attaching a surface side of the package substrate to a protective member integrally mounted on the annular frame; and maintaining a step of attracting and adhering with a working clamp of the cutting device a surface of the package substrate having the protective member; and in the first grinding step, the first flat grinding stone is brought into contact with the sealing resin layer on the back side of the package substrate, and the a flat grinding stone and the package substrate are relatively moved in a grinding feed direction to grind the sealing resin layer of the package substrate to a first thickness; and a second grinding step is performed to perform the first grinding After the step, the second flat grinding stone is brought into contact with the sealing resin layer on the back side of the package substrate, and the second flat grinding stone and the package substrate are relatively moved in the grinding feed direction, and The sealing resin layer of the package substrate is ground to a desired thickness.

Preferably, the disk-shaped first flat grinding stone and the disk-shaped second flat grinding stone are made of a disc-shaped wheel base and a nickel-plated method for fixing the abrasive grains to The plated stone layer on the outer surface of the wheel base is formed.

Preferably, the average abrasive grain diameter of the disk-shaped second flat grinding stone is equal to or less than the average abrasive grain diameter of the disk-shaped first flat grinding stone.

In the present invention, the first flat grinding stone and the disk-shaped second flat grinding stone are configured to be mounted on the rotating shaft of the cutting device of the dual spindle, respectively. 1 flat grinding stone will seal the tree The grease layer is roughly ground to the first thickness, and the sealing resin layer is ground to a desired thickness by the second flat grinding stone, so that even without the grinding device, the cutting device can be efficiently ground by a cutting device A sealing resin layer of the package board.

2‧‧‧Cutting device

4‧‧‧Base

6‧‧‧Working table

7‧‧‧ fixture

8‧‧‧Bee belly

10‧‧‧Facsimile Holder

11‧‧‧Package substrate

11a‧‧‧ Surface of the package substrate

11b‧‧‧The back of the package substrate

12‧‧‧wafer box

13‧‧‧Electrode substrate (lead frame)

14‧‧‧1st column

15‧‧‧ remaining area of the periphery

15a‧‧‧Non-component area

16A‧‧‧1st cutting unit

16B‧‧‧2nd cutting unit

17a, 17b, 17c‧‧‧ component areas

19‧‧‧ round hole

21a‧‧‧1st dividing line

21b‧‧‧2nd dividing line

23‧‧‧Component Formation Department

25‧‧‧Electrode

27‧‧‧ components

29‧‧‧ sealing resin layer

34‧‧‧Shaft housing

35‧‧‧DAF (Die Attach Fi1m)

36, 36B‧‧‧ shaft

38‧‧‧ bracket flange

40‧‧‧ Nuts

42‧‧‧Fixed nuts

44‧‧‧1st flat grinding stone

44B‧‧‧2nd flat grinding stone

F‧‧‧Ring frame

T‧‧‧ cutting tape

T1‧‧‧ final processing thickness

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a cutting apparatus suitable for use in practicing the grinding method of the present invention.

Fig. 2 is an exploded perspective view of the first cutting unit.

Fig. 3 is a schematic side view of the first and second cutting units.

4 is a plan view of a package substrate.

Fig. 5 is a side view of the package substrate.

Fig. 6 is a perspective view showing a step of attaching a holding member.

Fig. 7 is a cross-sectional view for explaining a rough grinding step.

Figure 8 is a cross-sectional view for explaining the fine grinding step.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to Figure 1, a perspective view of a cutting apparatus 2 suitable for use in practicing the method of grinding a package substrate of the present invention is shown. 4 is a base of the cutting device 2, and the working chuck 6 is disposed to be movable back and forth in the X-axis direction through a cutting feed mechanism (not shown) and rotatably disposed on the base 4. 8 is a cover cutting feed mechanism Snake belly.

The mounting table 10 is placed on the susceptor 4 so as to be vertically movable in the vertical direction (Z-axis direction) by a hoisting machine (elevating means) (not shown). The crucible 12 on which the workpiece is stored is placed on the crucible mounting table 10.

The first column portion 14 having a gate shape is erected rearward of the susceptor 4, and the first cutting unit 16A and the second cutting unit 16B are movably attached to the first column portion in the Y-axis direction and the Z-axis direction. 14. The first and second cutting units 16A and 16B include disc-shaped flat grinding stones 44 and 44B that are attached to the tip end of the rotating shaft that is rotationally driven.

As shown in FIG. 2, the first cutting unit 16A includes a rotating shaft 36 rotatably housed in the rotating shaft housing 34, and a mounting flange 38 is attached to the front end of the rotating shaft 36, and is fixed by a nut 40. Further, a disc-shaped flat grinding grindstone 44 is attached to the bracket flange 38 and fixed by a fixing nut 42.

As shown in the schematic side view of Fig. 3, the front end portion of the rotating shaft 36 of the first cutting unit 16A is provided with a disk-shaped first flat grinding stone 44, and the front end portion of the rotating shaft 36B of the second cutting unit 16B is provided. The disc-shaped second flat grinding stone 44B. The cutting device 2 of the present embodiment is a counter-rotating device in which the first flat grinding stone 44 and the second flat grinding stone 44B are opposed to each other.

Here, the first flat grinding stone 44 and the second flat grinding stone 44B are both formed by electroplating diamond abrasive grains on the outer peripheral surface of the wheel base by nickel plating. Preferably, the average abrasive grain diameter of the diamond abrasive grains of the second flat grinding stone 44B is equal to or less than the average abrasive grain diameter of the diamond abrasive grains of the first flat grinding stone 44. Further, the widths of the first and second flat grinding stones 44 and 44B of the present embodiment are 15 mm.

Referring to Figure 4, a plan view of the package substrate 11 is shown. The package substrate 11 has, for example, a rectangular electrode substrate (lead frame) 13, and three element regions 17a, 17b of the illustrated example are present in a region surrounded by the outer peripheral region 15 and the non-element region 15a of the electrode substrate 13. , 17c.

In each of the element regions 17a, 17b, and 17c, a plurality of element forming portions 23 partitioned by the first and second dividing lines 21a and 21b which are vertically and horizontally arranged perpendicularly and horizontally are formed, and the element forming portions are formed one by one. 23 is formed with a plurality of electrodes 25.

Each of the electrodes 25 is insulated by a resin molded on the electrode substrate 13. By cutting the first dividing line 21a and the second dividing line 21b, the electrodes 25 of the respective elements appear on both sides.

As shown in FIG. 5, the element 27 is adhered to the back surface of each of the element forming portions 23 of the element regions 17a, 17b, and 17c via a DAF (Die Attach Film) 35, and the electrodes provided on the respective elements 27 are connected to the electrode 25.

Further, each of the elements 27 of the element regions 17a, 17b, and 17c is sealed with a resin, and a sealing resin layer 29 is formed on the back surface of each of the element regions 17a, 17b, and 17c. As shown in FIG. 2, the four corners of the electrode substrate 13 are formed with a circular hole 19.

A grinding method of the package substrate of the present invention using the cutting device 2 configured as described above will be described. In the method of grinding a package substrate of the present invention, first, a step of adhering the surface of the package substrate 11 to the protective member of the protective member integrally formed on the annular frame F is performed.

That is, as shown in Fig. 6, the dicing tape T which is a protective member attached to the annular frame F as the outer peripheral portion is adhered to the surface 11a side of the package substrate 11. Thereby, the sealing resin layer 29 of the package substrate 11 is exposed.

After the protective member pasting step is performed, the dicing tape 6 is used to attract and hold the dicing tape T as a protective member through the dicing tape T. The surface 11a side of the substrate 11 is sandwiched and fixed by the clamp frame 7.

Next, as shown in FIG. 7, a rough grinding step (first grinding step) is performed: a first flat grinding in a disk shape that is mounted on the rotating shaft 36 of the first cutting unit 16A and rotated at a high speed (for example, 20,000 rpm) The grindstone 44 contacts the sealing resin layer 29 on the back surface 11b side of the package substrate 11, and causes the first flat grinding grindstone 44 and the package substrate 11 held on the working chuck 6 to be fed at a predetermined processing feed rate. The sealing resin layer 29 of the package substrate 11 is ground to the first thickness by the first flat grinding stone 44 in the direction (X-axis direction). Here, the first thickness means a thickness which is thicker than a final processing thickness t1 of the package substrate 11 by a predetermined amount.

The grinding processing conditions of the rough grinding step can be set, for example, as follows.

Number of rotations of the shaft 36: 20000 rpm

Processing feed rate (grinding feed rate): 50mm/s

The measurement of the flat grinding stone 44: 7mm (the overlap is 8mm)

After performing the rough grinding step (first grinding step), as shown in FIG. 8, a fine grinding step (second grinding step) is performed: the rotating shaft 36B attached to the second cutting unit 16B is rotated at a high speed (for example) The disk-shaped second flat grinding stone 44B of 20000 rpm) contacts the sealing resin layer 29 of the package substrate 11 on which the rough grinding step has been performed, and the flat grinding stone 44B and the package held in the working chuck 6 The substrate 11 is relatively moved in the grinding feed direction (X-axis direction) at a predetermined processing feed speed, and the sealing resin layer 29 of the package substrate 11 is ground to a final processed thickness t1.

The processing conditions of the fine grinding step can be set, for example, as follows.

Rotary shaft rotation number: 20000rpm

Processing feed rate (grinding feed rate): 50mm/s

The measurement of the flat grinding stone 44B: 7mm (the overlap is 8mm)

Furthermore, in the present embodiment, both the rough grinding step and the fine grinding step are to fix the flat grinding stone 44, 44B in the X-axis direction, and then the working clamping table 6 is along the X at a predetermined machining feed speed. It is implemented by machining in the axial direction.

Since the first flat grinding stone 44 having a large average abrasive grain diameter is coarsely ground to a final working thickness t1, the second flat grinding stone 44B having a fine average abrasive diameter is used to refine the residual thickness. Grinding to the final processing thickness t1, the sealing resin layer 29 can be efficiently ground, and the ground surface can be processed neatly.

11a‧‧‧ Surface of the package substrate

11b‧‧‧The back of the package substrate

13‧‧‧Electrode substrate (lead frame)

16B‧‧‧2nd cutting unit

27‧‧‧ components

29‧‧‧ sealing resin layer

35‧‧‧DAF (Die Attach Film)

36B‧‧‧ shaft

44B‧‧‧2nd flat grinding stone

T‧‧‧ cutting tape

T1‧‧‧ final processing thickness

Claims (3)

A method for grinding a package substrate is to use a first cutting means having a disk-shaped first flat grinding stone attached to a tip end of a first rotating shaft, and a disk shape provided at a tip end of the second rotating shaft In the second cutting device for grinding the second grinding tool, the sealing resin layer of the package substrate is ground to a desired thickness, and the package substrate is such that the surface of the element having the plurality of electrodes faces the electrode substrate. And a plurality of elements are disposed on the electrode substrate at predetermined intervals, and have a sealing resin layer that is resin-sealed to a back surface of a plurality of elements of the electrode substrate, and the grinding method of the package substrate includes: a protective member a bonding step of adhering the surface side of the package substrate to a protective member integrally attached to the annular frame; and maintaining a step of sucking and holding the surface side of the package substrate to which the protective member is adhered by the working chuck of the cutting device; 1 grinding step, after performing the holding step, the first flat grinding stone is brought into contact with the sealing resin layer on the back side of the package substrate, and the first flat grinding stone and the first flat grinding stone are The package substrate is relatively moved in the grinding feed direction to grind the sealing resin layer of the package substrate to the first thickness; and the second grinding step is performed after the first grinding step is performed The flat grinding stone contacts the sealing resin layer on the back side of the package substrate, and the second flat grinding stone and the package substrate are relatively moved in the grinding feed direction, and the sealing resin of the package substrate Layer grinding to hope The thickness is up. The method for grinding a package substrate according to claim 1, wherein the disk-shaped first flat grinding stone and the disk-shaped second flat grinding stone are a disk-shaped wheel base, and The abrasive grain is fixed by a nickel plating method to an electroplated grindstone layer on the outer peripheral surface of the wheel base. The method for grinding a package substrate according to claim 1 or 2, wherein the average abrasive grain diameter of the disk-shaped second flat grinding stone is the average abrasive grain of the first flat grinding stone of the disk shape Below the diameter.