TWI673783B - Processing method of package substrate - Google Patents

Abstract

Effortlessly arrange elements on the thermal diffusion substrate without burrs Division of a package substrate formed by resin sealing.

Perform the following steps: Cut The groove formation step cuts the resin into the depth of the thermal diffusion substrate and cuts along the predetermined division line to leave the resin. The resin cutting step irradiates the resin with a wavelength that is absorbent to the resin along the cutting groove. Infrared laser light to cut the remaining resin; and a dividing step of radiating laser light having a wavelength absorptive to the exposed thermal diffusion substrate, cutting the thermal diffusion substrate along a predetermined division line, and dividing into individual package elements In this way, the time required for cutting the resin and the thermal diffusion substrate can be shortened, respectively, and the time required for dividing the entire package substrate can be shortened.

Description

Processing method of package substrate Field of invention

The present invention relates to a method for dividing a package substrate into individual package elements.

Background of the invention

A package substrate in which a plurality of elements are arranged on a heat diffusion substrate and the elements are sealed with epoxy resin or silicone resin is cut by cutting or the like between adjacent elements and divided into individual elements. Packaged components as a unit. Due to factors such as high heat dissipation and low price, metals such as stainless steel and copper are used for the heat diffusion substrate (see, for example, Patent Document 1).

In the division of the package substrate, a method in which only the resin is cut by a cutter, and the thermal diffusion substrate is cut by laser processing (Japanese Patent Application No. 2013-168794), or by laser processing may be considered. Method for breaking both resin and thermal diffusion substrate (Japanese Patent Application No. 2014-153646).

Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2009-224683

Summary of invention

However, when the rotating cutter cuts into the package substrate and cuts it, the cut portion of the metal thermal diffusion substrate is liable to generate burrs. If only the resin is cut by a cutter and the thermal diffusion substrate is cut by laser processing, although burrs can be prevented, the cutting resistance of the cutting blade will increase because the tip of the cutter contacts the thermal diffusion substrate when cutting the resin. Unable to increase cutting speed. On the other hand, when cutting the resin by laser processing, in order to prevent the cut surface from scorching, it is necessary to suppress the output of the pulsed laser light and ablate it several times to cut it, and it takes a lot of time when cutting. Problems in productivity. This problem becomes more significant as the resin is thicker.

The present invention has been made in view of such problems, and an object thereof is to efficiently divide a package substrate configured by arranging elements on a heat diffusion substrate and sealing them with resin without generating burrs.

The present invention is a processing method of a packaging substrate, which is a processing method of packaging substrates that are divided into packaging substrates by dividing the packaging substrate along predetermined division lines formed in a grid shape on the surface of the thermal diffusion substrate. Components are arranged in a plurality of areas divided by the predetermined dividing line, and the plurality of components are covered with resin to form a resin layer. The processing method of the aforementioned package substrate includes a cutting groove forming step to maintain a mechanism to hold the package. Position the cutting blade on the thermal diffusion substrate side of the substrate, cut the resin to the depth of the thermal diffusion substrate after cutting at a predetermined division line, and then cut along the predetermined division line to make the resin remain and form a cutting groove along the predetermined division line. ; The resin cutting step irradiates infrared laser light having a wavelength absorptive to the resin along a cutting groove to cut off the remaining resin. The cutting groove is provided along the cutting groove forming step and the thermal diffusion substrate side is held by a holding mechanism. Forming a package substrate with a division line; and a division step, irradiating laser light having a wavelength absorptive to the exposed thermal diffusion substrate along the division line, cutting the thermal diffusion substrate along the division line, and dividing For each package element, the aforementioned planned division line is a planned division line along the package substrate on which the heat diffusion substrate side is held by the holding mechanism by the resin cutting step.

Ideally, the infrared laser light used in the resin cutting step is a CO ₂ laser with a pulse width of 10 ns to 10 μs .

Since the present invention does not use a cutter to cut the thermal diffusion substrate, it is possible to prevent the occurrence of burrs and prevent a reduction in cutting speed. Also, since the cutting of the resin is performed by cutting and laser processing, it is possible to shorten the resin cutting time. Accordingly, the time required for cutting the resin and the heat diffusion substrate can be shortened, respectively, and the time required for dividing the package substrate can be shortened as a whole. In addition, since the resin is cut by cutting and laser processing, even if the substrate is thick, the time required for cutting does not increase, and the productivity does not decrease.

1‧‧‧Processing Equipment

2‧‧‧ holding agency

20‧‧‧ keep face

21‧‧‧ trench

22‧‧‧ suction hole

23‧‧‧Rotating mechanism

3‧‧‧ cutting mechanism

30‧‧‧ shaft

31‧‧‧shell

32‧‧‧Cutter

4‧‧‧The first laser processing mechanism

40‧‧‧The first irradiation head

41、51‧‧‧Auxiliary gas introduction department

42, 52‧‧‧ condenser lens

5‧‧‧The second laser processing mechanism

50‧‧‧ 2nd irradiation head

6‧‧‧ processing feed mechanism

60, 70, 80, 90‧‧‧ ball screw

61, 71, 81, 91‧‧‧ rails

62, 72, 82, 92‧‧‧ Motors

63, 73‧‧‧ mobile board

7‧‧‧ index feed mechanism

8‧‧‧cut into the feed mechanism

83, 93‧‧‧ Lifting plate

9‧‧‧ Lifting means

94‧‧‧ support

10‧‧‧ package substrate

11‧‧‧ thermal diffusion substrate

110‧‧‧ surface

12‧‧‧ Components

13‧‧‧resin layer

14‧‧‧ divided scheduled line

15‧‧‧ cutting groove

16‧‧‧Resin Residual Department

17‧‧‧ resin cut trench

18‧‧‧ substrate cutting groove

LB1, LB2 ‧‧‧ laser light

X, Y, Z‧‧‧ directions

FIG. 1 is a perspective view showing an example of a processing apparatus.

FIG. 2 is an enlarged sectional view showing an example of a package substrate.

FIG. 3 is an enlarged sectional view showing a cutting groove forming step.

FIG. 4 is an enlarged cross-sectional view showing a package substrate on which a cutting groove is formed.

Fig. 5 is an enlarged sectional view showing a resin cutting step.

FIG. 6 is an enlarged cross-sectional view showing a division step.

Forms used to implement the invention

The processing device 1 shown in FIG. 1 includes a holding mechanism 2 that holds a workpiece, a cutting mechanism 3 that performs a cutting process on a workpiece that is held by the holding mechanism 2, and a mine that performs a mine on the workpiece that is held by the holding mechanism 2. A first laser processing mechanism 4 and a second laser processing mechanism 5 for laser processing.

The holding mechanism 2 includes a holding surface 20 formed in a flat shape, grooves 21 formed vertically and horizontally at positions corresponding to the planned division lines for cutting the workpiece, and areas respectively provided in the areas divided by the grooves 21.中 的 孔 孔 22。 In the suction hole 22. A rotation mechanism 23 that rotates the holding mechanism 2 is disposed below the holding mechanism 2.

The cutting mechanism 3 includes a rotation shaft 30 having an axis center in the Y-axis direction, a housing 31 rotatably supporting the rotation shaft 30, and a cutting blade 32 mounted on a front end of the rotation shaft 30.

The first laser processing mechanism 4 includes a first irradiation head 40 and an auxiliary gas introduction section 41 that allows an auxiliary gas to flow into the first irradiation head 40. In addition, the second laser processing mechanism 5 includes a second irradiation head 50 and an auxiliary gas introduction portion 51 that allows an auxiliary gas to flow into the second irradiation head 50.

The holding mechanism 2 is processed and fed in the X-axis direction by a processing feed mechanism 6. The processing feed mechanism 6 includes a ball screw 60 having an axial center in the X-axis direction, a pair of guide rails 61 arranged in parallel with the ball screw 60, and a ball screw. A motor 62 that rotates the lever 60, and a moving plate 63 having a nut screwed into the ball screw 60 inside and a bottom portion slidingly connected to the guide rail 61, and the ball screw 60 is rotated by the motor 62 to receive the moving plate 63. The guide rail 61 is configured to move in the X-axis direction. When the moving plate 63 moves in the X-axis direction, the rotation mechanism 23 and the holding mechanism 2 supported by the moving plate 63 also move in the X-axis direction.

The machining feed mechanism 6 and the holding mechanism 2 are indexed in the Y-axis direction (a direction orthogonal to the X-axis direction) by the index feed mechanism 7. The indexing feed mechanism 7 includes a ball screw 70 having an axis center in the Y-axis direction, a pair of guide rails 71 arranged in parallel with the ball screw 70, a motor 72 for rotating the ball screw 70, and a ball screw screwed inside the ball screw 70. The bottom of the nut 70 is slidably connected to the moving plate 73 of the guide rail 71, and the ball screw 70 is rotated by the motor 72, and the moving plate 73 is guided by the guide rail 71 and moves in the Y-axis direction. A processing feed mechanism 6 is disposed on the upper surface of the moving plate 73. When the moving plate 73 moves in the Y-axis direction, the processing feed mechanism 6 and the holding mechanism 2 also move in the Y-axis direction.

The cutting mechanism 3 performs a cutting feed in the Z-axis direction (a direction orthogonal to the X-axis direction and the Y-axis direction) by the cutting feed mechanism 8. The plunging and feeding mechanism 8 includes a ball screw 80 having an axial center in the Z-axis direction, a pair of guide rails 81 arranged in parallel with the ball screw 80, a motor 82 for rotating the ball screw 80, and a ball screw 80 screwed into the ball screw 80 inside. The side of the nut is slidably connected to the lifting plate 83 of the guide rail 81, and the ball screw 80 is rotated by the motor 82. The lifting plate 83 is guided by the guide rail 81 and moves up and down in the Z-axis direction. The cutting mechanism 3 is fixed to the side of the lifting plate 83, and the lifting plate 83 moves up and down in the Z-axis direction. The cutting mechanism 3 also moves up and down in the Z-axis direction.

The first laser processing mechanism 4 and the second laser processing mechanism 5 are supported by a lifting mechanism 9 so as to be movable up and down. The elevating mechanism 9 includes a ball screw 90 having an axial center in the Z-axis direction, a pair of guide rails 91 arranged in parallel with the ball screw 90, a motor 92 for rotating the ball screw 90, and a screw screwed into the ball screw 90 inside The cap and the side are slidably connected to the lifting plate 93 of the guide rail 91, and the ball screw 90 is rotated by the motor 92, and the lifting plate 93 is guided by the guide rail 91 to move up and down in the Z-axis direction. The first laser processing mechanism 4 and the second laser processing mechanism 5 are fixed to the side of the lifting plate 93 by a support table 94, and are raised and lowered in the Z-axis direction by the lifting plate 93. The first laser processing mechanism 4 and the second laser processing mechanism 5 The laser processing mechanism 5 also moves in the Z-axis direction.

A method of processing the package substrate 10 shown in FIG. 2 will be described below using the processing device 1 configured as described above. The package substrate 10 includes a thermal diffusion substrate 11, a plurality of elements 12 arranged on a surface 110 of the thermal diffusion substrate 11, and a resin layer (coating layer) 13 that covers the plurality of elements 12 with a resin. The thermal diffusion substrate 11 is made of, for example, stainless steel, copper, or the like, and has a metal substrate or an alumina ceramic substrate that has high heat dissipation and is inexpensive. On the other hand, the resin constituting the resin layer 13 is, for example, epoxy resin, silicone resin, or the like, and its thickness is, for example, about 1 mm.

Each element 12 is disposed in a region divided by a predetermined division line 14 formed on the surface 110 of the heat diffusion substrate 11 in a grid pattern. The package substrate 10 is divided along package division lines 14 to be divided into package elements each having a single element 12 as a unit.

(1) Cutting groove formation step

As shown in FIGS. 2 and 3, the heat diffusion substrate 11 side of the package substrate 10 is held on the holding surface 20 of the holding mechanism 2, and the upper surface of the resin layer 13 is exposed. Further, as shown in FIG. 3, the cutting blade 32 constituting the cutting mechanism 3 shown in FIG. 1 is rotated at a high speed and positioned above the planned division line 14, the cutting blade 32 is cut into the resin layer 13, and the cutting blade 32 is lowered to The lower end of the cutting blade 32 does not reach the depth of the heat diffusion substrate 11, and the feed holding mechanism 2 is processed in the X-axis direction by the processing feed mechanism 6 shown in FIG. 1. In this way, as shown in FIG. 4, the cutting groove 15 is formed along the planned division line 14. By cutting the cutting blade 32 to a depth not reaching the heat diffusion substrate 11, the resin layer 13 is formed below the cutting groove 15 as a portion that is not cut by the cutting blade 32, that is, the resin residual portion 16. This step is performed under the following processing conditions, for example.

Cutting tool thickness: 200 [ μ m]

Cutter diameter: 52 [mm]

Rotating speed of cutter: 20000 [rpm]

Processing feed rate: 100 [mm / s]

With the indexing feed mechanism 7 shown in FIG. 1, the cutting mechanism 3 is indexed and fed in the Y-axis direction at intervals between the adjacent predetermined division lines 14 and along all the same directions. After cutting the division line 14 in this way, the holding mechanism 2 is rotated 90 degrees and then the same cutting is performed, thereby forming cutting grooves 15 along all the division lines 14.

In the cutting groove forming step, the cutting blade 32 is cut to a depth not reaching the thermal diffusion substrate 11, so that the cutting blade does not cut into the thermal diffusion substrate 11. Therefore, it is possible to prevent a reduction in cutting speed due to an increase in cutting resistance.

(2) Resin cutting step

Next, as shown in FIG. 5, the first laser irradiation head constituting the first laser processing mechanism 4 is held in a state where the heat diffusion substrate 11 side of the package substrate 10 subjected to the cutting groove formation step is held by the holding mechanism 2. 40 is positioned above the planned division line 14. Then, the condenser lens 42 is irradiated with the laser light LB1 having a wavelength which is absorptive to the resin constituting the resin layer 13 along the cutting groove 15 formed on the predetermined division line 14. When the laser beam LB1 is irradiated, the auxiliary gas is introduced from the auxiliary gas introduction section 41 and is ejected from the first irradiation head 40. This step is performed under the following processing conditions, for example.

Laser light wavelength: CO ₂ laser (9.2 ~ 10.6 [ μ m])

Repetition frequency: 100 [kHz]

Pulse width: 10 [ns] ~ 10 [ μ s]

Average output: 40 [W]

Condensing spot diameter: φ 100 [ μ m]

Processing feed rate: 600 [mm / s]

Auxiliary gas: 1 [MPa]

The laser light LB1 is focused on the resin remaining portion 16 of the resin layer 13. Further, the processing feed holding mechanism 2 is processed in the X-axis direction by the processing feed mechanism 6 shown in FIG. 1. In this way, the ablation process is performed along the planned division line 14 to form a resin cutting groove 17. Since the laser light LB1 is absorbent to the resin and absorbs less than the thermal diffusion substrate 11, it is possible to form the resin cutting groove 17 and the resin layer 13 by processing only the resin remaining portion 16 without cutting the resin layer 13. Perform ablation processing. When the resin layer 13 is cut, the surface 110 of the thermal diffusion substrate 11 is exposed from this portion.

By the indexing feed mechanism 7 shown in FIG. 1, in the Y-axis direction After cutting the feed mechanism 3 at intervals between adjacent division lines 14 and performing laser processing along all the division lines 14 in the same direction, the holding mechanism 2 is rotated 90 degrees. The same cutting is performed again to form the resin cutting grooves 17 along all the division lines 14.

From the viewpoint of preventing the both sides of the resin cutting groove 17 from being burnt in the resin cutting step, since the output of laser light cannot be improved, the holding mechanism 2 must also be moved back and forth several times to perform the laser light. Irradiation of LB1, but the resin layer 13 has been cut in advance in the cutting groove forming step, so the time required to cut the resin can be shortened compared to the case where the resin is cut by laser processing without the cutting groove forming step. .

(3) Segmentation steps

Next, as shown in FIG. 6, the second laser head 50 constituting the second laser processing mechanism 5 will be held in a state where the heat diffusion substrate 11 side of the package substrate 10 subjected to the resin cutting step is held by the holding mechanism 2. It is positioned above the planned division line 14. Then, the condenser lens 52 radiates laser light LB2 having a wavelength absorptive to the thermal diffusion substrate 11 along the resin cutting groove 17 formed on the planned division line 14, and cuts the thermal diffusion along the planned division line 14. Substrate 11. When the laser beam LB2 is irradiated, the auxiliary gas is introduced from the auxiliary gas introduction portion 51 and is ejected from the second irradiation head 50. This step is performed under the following processing conditions, for example.

Laser light wavelength: YAG laser or fiber laser (1.06 [ μ m])

Repetition frequency: 20 [kHz]

Pulse width: variable

Average output: 150 ~ 500 [W]

Condensing spot diameter: φ 50 [ μ m]

Processing feed speed: 160 [mm / s]

Auxiliary gas: 1 [MPa]

The average output and pulse width of the laser light are changed depending on the material or thickness of the thermal diffusion substrate 11. For example, when the thermal diffusion substrate 11 is made of copper that is easy to transfer heat, in order to suppress the heat conduction caused by the output energy of the laser light, the pulse width can be shortened, or the average output can be increased. In addition, the thickness of the thermal diffusion substrate 11 is 100 to 300 μm . As long as the thickness is increased, the average output or the pulse width can be increased for processing.

The laser light LB2 is focused on the heat diffusion substrate 11 below the resin cut groove 17. Then, the processing feed holding mechanism 2 is processed in the X-axis direction by the processing feed mechanism 6 shown in FIG. 1. In this way, the substrate cutting groove 18 can be formed along the planned division line 14. At this time, since the slag generated by the laser processing falls to the groove 21, it does not adhere to the side surface of the substrate cutting groove 18 or the like.

By the indexing feed mechanism 7 shown in FIG. 1, the feed holding mechanism 2 is indexed one by one in the Y-axis direction at intervals of adjacent predetermined division lines 14 and extends along the X-axis direction. After all of the division lines 14 are laser-processed as described above, when the substrate cutting grooves 18 are formed along all the division lines 14 by performing the same laser processing after rotating the holding mechanism 2 by 90 degrees, The package substrate 10 is divided into package elements with each element 12 as a unit.

In the dividing step, since the thermal diffusion substrate 11 is cut by laser processing without using a cutter, it is possible to prevent the substrate from cutting both sides of the groove 18 Burrs occur on the face. Further, in the division step, the output of the laser beam LB2 can be increased, so that the substrate cutting groove 18 can be formed in one processing feed.

Claims (2)

A processing method of a packaging substrate is a processing method of packaging substrates that are divided into individual packaging substrates by dividing the packaging substrates along predetermined division lines formed in a grid shape on the surface of the heat diffusion substrate. Components are arranged in a plurality of areas divided by a predetermined line, and the plurality of components are covered with resin to form a resin substrate package substrate. The processing method of the package substrate includes a cutting groove forming step to hold the holding mechanism. The thermal diffusion substrate side of the packaging substrate is positioned at a cutting line and cuts the resin to a depth not exceeding the thermal diffusion substrate, and then cuts along the predetermined dividing line, so that the resin remains and is formed. The resin remaining part forms a cutting groove along the predetermined division line; the resin cutting step irradiates the resin along the cutting groove with infrared laser light having an absorptive wavelength to the resin, cuts the resin remaining part, and the cutting groove It is the pre-segmenting step along which the cutting groove forming step is performed and the package substrate on the heat diffusion substrate side is held by a holding mechanism. And dividing step, irradiating laser light having a wavelength absorptive to the exposed thermal diffusion substrate along the predetermined division line, cutting the thermal diffusion substrate along the predetermined division line, and dividing into one For the individual package elements, the aforementioned planned division line is a planned division line for carrying out the resin cutting step and holding the package substrate on the heat diffusion substrate side by a holding mechanism. For example, the method for processing a package substrate according to claim 1, wherein the infrared laser light used in the resin cutting step is a CO ₂ laser, and the pulse width is 10 ns to 10 μs.