JP2014226682A - Laser processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent burning damage or flaw damage in a surface of a transparent resin lens body 40 for sealing an optical semiconductor element installed in respective sections of a substrate surface, in laser processing for cutting a substrate 10.SOLUTION: A laser processing method includes a forward passage cutting process of cutting by irradiating a laser beam L up to its central position C from a starting end side position 30a of a first row section 31 along a cutting expected line 20 of the substrate 10, stopping irradiation of the laser beam L up to the starting end side position 30a of a second row section 32 from the central position C of the first row section 31 and also cutting the respective sections 60 up to its central position C from the starting end side position 30a of the respective row sections by repeating irradiation and stopping of the laser beam L up to the final row section, and a backward passage cutting process of cutting by irradiating the laser beam L up to its central position C from a tail end side position 30b in the final row section of the cutting expected line 20 via this forward passage cutting process and also cutting the respective sections 70 up to its central position C from the tail end side position 30b of the respective row sections by repeating the irradiation of the laser beam L up to the first row section 31.

Description

  The present invention relates to a laser processing method for cutting and separating an optical semiconductor element mounted in each section set on a substrate surface using a laser processing means, and in particular, processing scattered matter (debris: generated during laser processing). The present invention relates to an improvement in a laser processing method that can efficiently prevent burning or damage of a transparent resin lens body that seals an optical semiconductor element.

By the way, it is known that scattered workpieces are generated at the time of laser processing in which the surface of a workpiece is irradiated with laser light to cut the workpiece by so-called thermal processing.
In addition, if this work scattering matter adheres to the periphery of the processing part, there is a problem that it is not possible to obtain processing quality and accuracy, so when the laser beam is irradiated to the work piece, the assist gas is blown to the surrounding area, It is known that the assist gas and the processing scattered matter are sucked to the outside and discharged (for example, see Patent Document 1).
In addition, this type of laser processing head has a laser beam irradiation and assist gas spraying work efficiency on the surface of the work, and an operation efficiency of sucking and discharging the assist gas and work scattered matter from the periphery of the processing part to the outside. In consideration, the distance between the bottom surface of the laser processing head and the surface of the workpiece is usually close.
Therefore, when laser processing is performed with the distance between the bottom surface of the laser processing head and the surface of the workpiece close, there is an advantage that each of the above-described work efficiencies can be improved.

However, for example, a workpiece formed as a shape in which a large number of concavo-convex portions are arranged on the surface of a substrate so that a large number of transparent resin lens bodies for sealing an optical semiconductor element are projected on the surface of the substrate. In order to prevent contact between the bottom surface of the laser processing head and each transparent resin lens body at the time of laser processing, the bottom surface of the laser processing head is positioned higher than the height position of each transparent resin lens body. It is necessary to set so that
Therefore, in this case, since the distance between the bottom surface of the laser processing head and the surface of the substrate that becomes the processing portion where the cutting line is set is inevitably widened (separated), the distance between the two cannot be made closer. For this reason, there is a problem that the above-described work efficiency is lowered.

Further, in the case of laser processing a workpiece formed as a shape in which a large number of uneven portions are arranged on the laser light irradiation surface, there are the following problems.
A workpiece W shown in FIG. 7 has a large number of transparent resin lens bodies 4 for sealing an optical semiconductor element in a large number of sections 3 provided by setting a grid-like cutting line 2 on the surface of the substrate 1. It is formed as a shape in which a large number of irregularities are arranged on the surface of the substrate 1.
Such workpiece W can also be subjected to laser processing for cutting and separating each section 3 by irradiating laser beam L along the planned cutting line 2.
In this case, the laser beam L is irradiated linearly and continuously from the start end portion 1a to the end portion 1b of the substrate 1 along the planned cutting line 2 set on the surface of the substrate 1.

In the laser processing of the workpiece W shown in FIG. 7, since the distance between the bottom surface of the laser processing head and the substrate surface on which the planned cutting line 2 is set is widened, the laser beam L is irradiated onto the planned cutting line 2. The working efficiency of discharging the assist gas sprayed at the time and the processing scattered matter to the outside of the substrate surface is deteriorated.
Moreover, since the transparent resin lens body 4 (convex part) protrudes on both sides of the planned cutting line 2 on the substrate surface, the flow of the assist gas sprayed on the planned cutting line 2 changes.
That is, as shown in FIG. 7 (2), the laser beam L applied to the planned cutting line 2 on the substrate surface and the assist gas sprayed to the planned cutting line 2 are projected along the planned cutting line 2 (in the example shown in the figure). In the section 6 from the position 3a on the start end side to the center position C in each section 3, the assist gas and the processing scattered matter 8 trapped by this are in the scanning direction of the laser light L. Flows in the opposite direction (upward in the example).
In the section 7 that passes through the center position C of each section 3 and reaches the terminal position 3b, contrary to the above, the assist gas and the processing scattered matter 8 trapped therein are laser light. It flows in the same direction as the scanning direction of L (downward in the example).
Due to the fluid action of the assist gas and the processed scattered matter 8, when the processed scattered matter collides with or adheres to the surface of the transparent resin lens body 4, the surface of the transparent resin lens body 4 burns and burns out. Or the bad effect that this is damaged and quality is reduced arises.
Furthermore, the collision action of the processing scattered matter 8 with respect to the transparent resin lens body 4 in each section 3 or the adhesion action of the processing scattered matter 8 is the section 6 from the position 3a on the start end side to the center position C in each section 3. However, it tends to increase in the section 7 that passes through the center position C of each section 3 and reaches the terminal position 3b.
Therefore, as a result, there is a problem that a portion 9 that easily burns its surface is generated in the section 7 that passes through the center position C of each section 3 and reaches the position 3b on the end side.

  If a large number of irregularities are arranged on the surface of the workpiece W irradiated with laser light, the so-called CW laser processing by so-called CW oscillation (continuous oscillation) or pulse laser processing by pulse oscillation can be used. There is a tendency that the processed scattered matter remains and adheres to the laser light irradiation surface side. This is because the distance between the bottom surface of the laser processing head and the laser light irradiation surface (substrate surface) is widened, so that processing scattered matter is likely to be generated on the laser light irradiation surface, and the assist gas and processing scattered matter are further transferred to the substrate. This is thought to be due to the poor work efficiency of discharging to the outside of the surface.

Moreover, although it is guessed, when the laser beam L irradiated to the cutting line 2 on the substrate surface and the assist gas sprayed on the cutting line 2 are scanned along the cutting line 2, one side in the section 3 When the first half (section 6) is cut, it is estimated that the flow of the assist gas including the processed scattered matter 8 is reflected by the transparent resin lens body 4 (convex portion) and flows in the direction opposite to the scanning direction. (Upward in Fig. 7 (2)). At this time, it is estimated that the flow of the assist gas including the processing scattered matter 8 flowing between the two convex portions 4 in the vicinity of the center position C of the section 3 is small.
Moreover, although it is guessed, when cutting the second half (section 7) of one side in the section 3, the flow of the assist gas is reflected by the transparent resin lens body 4 (convex portion) and flows in the same direction as the scanning direction. Is estimated to increase (downward in Fig. 7 (2)). That is, since the assist gas including the processing scattered matter 8 spreads from the center position C of the section 3 along the shape of the convex portion 4, it is estimated that a portion 9 that easily burns the substrate surface is generated.

JP-A-9-192870 (paragraph [0009] on the second page, paragraph [0029] on the fourth page, FIG. 1 etc.)

  In the present invention, laser processing is performed on a workpiece formed as a shape in which convex portions (transparent resin lens bodies for sealing an optical semiconductor element) are arranged in a large number of sections provided in a lattice shape on the surface of a substrate. An object of the present invention is to provide a laser processing method capable of preventing the projections from being burned or damaged by suppressing the collision or adhesion of the processing scattered matter to the projections.

In the laser processing method according to the present invention for achieving the above-described object, the semiconductor device is mounted and sealed in a number of sections 30 in which the grid-like cutting lines 20 are set on the surface of the substrate 10, By irradiating the workpiece W having a height difference between the height of the surface of the substrate 10 and the height of the semiconductor device sealing body (40) along the planned cutting line 20, the substrate 10 Is a laser processing method for cutting and separating each section 30,
The laser beam L is irradiated from the starting end position 30a in the section 31 of the first row to the center position C along the planned cutting line 20 of the substrate 10 to cut the section 60 of the planned cutting line 20, and The irradiation of the laser beam L is stopped from the center position C in the section 31 of the first row to the position 30a on the start end side in the section 32 of the second row so as not to cut the section 70 of the planned cutting line 20, By repeatedly irradiating and stopping the laser beam L on the planned cutting line 20 until reaching the section of the last row, the center thereof from the position 30a on the start end side in the section 30 of each row along the planned cutting line 20 is obtained. An outward cutting step of cutting each section 60 of the planned cutting line 20 by irradiating the laser beam L to the position C;
The laser beam L is irradiated from the position 30b on the end side in the section 30 of the last row of the planned cutting line 20 that has undergone the above-described cutting process to the center position C in the section 31 of the first row, and uncut portions ( A return path cutting process for cutting each section 70 of the planned cutting line 20 that is not cut in the forward path cutting process;
Assist gas that blows and supplies the assist gas 90 to the portion of the planned cutting line 20 (coaxial with the laser light L) at least when the laser beam L is irradiated onto the planned cutting line 20 of the substrate 10 in the forward path cutting process and the backward path cutting process. Spraying process,
Further, the forward path cutting process is performed along each planned cutting line 20 of the substrate 10, and then each of the sections 30 on the substrate 10 is performed by performing the backward path cutting process of the planned cutting line 20 that has undergone the forward path cutting process. It is characterized by being cut and separated separately.

  The laser processing method according to the present invention is characterized in that the semiconductor device is formed by sealing an optical semiconductor element into a sealing body (40) made of a transparent resin lens body.

  Further, in the laser processing method according to the present invention, the assist gas 90 sprayed on the site of the planned cutting line 20 and the processing scattered matter 80 generated from the site of the planned cutting line 20 are sucked to the outside during the assist gas spraying process. A suction / discharge process of discharging is performed.

Further, in the laser processing method according to the present invention, air is forcibly discharged from the laser beam irradiation side to the opposite side in the forward path cutting portion 60a formed along the planned cutting line 20 in the forward path cutting step. By performing the step of discharging the work gas 80 generated from the assist gas sprayed to the site of the planned cutting line 20 and the site of the planned cutting line 20,
The step of forcibly discharging air from the laser beam irradiation side to the opposite side is performed in the return path cutting portion 70a formed along the planned cutting line 20 in the return path cutting step.

  According to the method of the present invention, at the time of laser processing on a workpiece W formed as a shape in which convex portions (transparent resin lens bodies 40) are arranged in a large number of sections 30 provided in a lattice pattern on the surface of the substrate 10. In addition, since the collision or adhesion of the processing scattered matter 80 to each convex portion can be efficiently prevented or suppressed, it is possible to prevent the respective convex portions from being burned or damaged.

  Further, according to the method of the present invention, the adhesion of the processed scattered matter 80 to each convex portion can be efficiently prevented or suppressed, and the laser processing quality is improved. The cleaning process can be labor-saving or simplified.

It is explanatory drawing of the laser processing method which concerns on this invention, Comprising: It is a partially notched front view which shows the structure outline of a laser processing apparatus. FIG. 2 is a partially cutaway enlarged front view showing a main part of the laser processing apparatus corresponding to FIG. 1. FIG. 3 (1) is a plan view showing a main part of a workpiece, and FIG. 3 (2) is an enlarged plan view of the main part. FIG. 4 is an enlarged plan view of a main part of the workpiece corresponding to FIG. 3, showing a state after an outward cutting process. FIG. 5 (1) is a plan view showing a main part of a workpiece, and FIG. 5 (2) is an enlarged plan view of the main part. FIG. 6 is an enlarged plan view of a main part of the workpiece corresponding to FIG. 5, showing a state after a return path cutting step. FIG. 7 (1) is an explanatory view of a technical problem when laser processing is performed on a workpiece having a large number of irregularities on the substrate surface using a conventional laser processing method. FIG. 7B is a plan view showing the main part, and FIG. 7B is an enlarged plan view of the main part.

  Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows a laser processing unit 50 in the laser processing apparatus.
The laser processing unit 50 includes a suction table 51 that sucks and holds the substrate 10 (workpiece W) via a suction pad 51a.
The laser processing unit 50 includes a laser beam irradiation means 52 for irradiating a laser beam L to a processing unit (scheduled cutting line 20) in the workpiece W held on the suction table 51, and an assist such as argon. Assist gas supply means 53 for spraying and supplying the gas 90 is provided.
It should be noted that the processing scattered matter discharging means 54 for sucking and discharging the processing scattered matter 80 scattered from the processing portion on the flow of the assist gas 90 to the outside of the substrate surface can be provided.

Further, FIG. 1 shows a portion of a laser processing head 55 that is disposed to face the surface of the workpiece W.
As shown in FIG. 2, the laser processing head 55 is provided with an opening 55 a that doubles as an irradiation port for the laser light L and a blowing port for the assist gas 90.
Further, the laser processing apparatus is provided with an imaging means for the workpiece W held on the suction table 51 and its control means (not shown), and the suction table 51 and the imaging means are relatively moved. Then, a processing part (scheduled cutting line 20) set on the surface of the substrate 10 (workpiece W) is detected, and an alignment (positioning of the cutting part) step for determining a laser processing part in the processing part is performed. It is provided so that it can.
The laser processing head 55 is provided with an assist gas 90 opened around the outside of the opening 55a and a suction / discharge port 55b for processing scattered matter 80 (see FIG. 2).

Further, the workpiece W described above is configured as follows.
That is, as shown in FIG. 3, the workpiece W has a large number of transparent resins for sealing the optical semiconductor elements in a large number of sections 30 provided by setting grid-like cutting lines 20 on the surface of the substrate 10. A lens body 40 (semiconductor device sealing body) is projected. Accordingly, the surface of the substrate 10 is formed in a shape in which a large number of uneven portions are arranged by the surface of the substrate 10 and the transparent resin lens body 40 (see FIG. 1).

Further, the method of laser processing the workpiece W held on the suction table 51 using the laser processing apparatus is basically the same as the conventional method.
That is, first, the processing part (scheduled cutting line 20) of the workpiece W is detected by the above-described alignment process, and the laser processing part in the processing part is determined.
Next, the laser beam L of the workpiece W is irradiated with the laser beam L condensed by the condenser lens 52a via the laser beam irradiation means 52.
Further, at the time of irradiation of the laser beam L to the laser processing site, the assist gas 90 is blown and supplied to the laser processing site of the workpiece W through the assist gas supply means 53.
At this time, while performing the laser processing by the irradiation of the laser beam L and the spraying of the assist gas 90, the processing scattered matter 80 scattered from the processing portion is removed from the processing portion via the processing scattered matter discharging means 54. It is possible to put it on the flow and suck it out of the substrate surface to be discharged (see FIG. 2).

Hereinafter, detailed description will be given of preventing the transparent resin lens body 40 from being burned or damaged by suppressing the collision or adhesion of the processed resin 80 to the transparent resin lens body 40.
That is, as shown in FIG. 3, first, the laser beam L is irradiated from the starting end side position 30a of the section 31 in the first row to the center position C along the planned cutting line 20 of the substrate 10 to be cut. Cut section 60 of line 20.
Then, by stopping the irradiation of the laser beam L from the center position C in the section 31 of the first row to the position 30a on the start end side in the section 32 of the second row, the section 70 of the planned cutting line 20 is not cut. .
Further, by repeating (intermittently) irradiating and stopping the laser beam L on the planned cutting line 20 until reaching the final column, the sections 30 of each column along the planned cutting line 20 are obtained. The forward cutting process of cutting only each section 60 of the planned cutting line 20 by irradiating the laser beam L from the position 30a on the starting end side to the center position C is performed.

In addition, an assist gas spraying step of spraying the assist gas 90 on the portion of the planned cutting line 20 (coaxial with the laser light L) is performed at least when the laser beam L is applied to the planned cutting line 20 of the substrate 10 in the forward path cutting step. .
In this forward cutting process, when the laser beam L irradiated to the cutting line 20 on the substrate surface and the assist gas sprayed to the cutting line 20 are scanned along the cutting line 20, In the section 60 from the position 30a to the center position C, as shown in FIG. 3 (2), the assist gas and the scattered scattered matter 80 trapped by the assist gas are in the direction opposite to the scanning direction of the laser beam L (see FIG. In the example, it flows upward).
In the forward cutting process, the colliding action of the processing scattered matter 80 against the transparent resin lens body 40 in each section 3 or the attaching action of the processing scattered matter 80 is the position 30a on the start end side in each section 30 as in the conventional example. Is less in the section 60 from the center position C to the center position C.

Further, as shown in FIG. 4, in the above-described outbound cutting step, the outbound path cutting portion 60 a is formed on the substrate 10. The forward path cutting portion 60a is a long and narrow hole (through hole) having a length from a position 30a on the start end side along the planned cutting line 20 to its center position C and having a required width.
As will be described later, in the backward path cutting step, the assist gas including the processing scattered matter 8 flows into the forward path cutting portion 60a and escapes from the front side to the back side of the substrate.

Next, the laser beam L is irradiated from the terminal-side position 30b in the section 30 of the last row of the planned cutting line 20 that has undergone the above-described cutting process to the center position C in the section 31 of the first row. A return path cutting process is performed for cutting each section 70 of the planned cutting line 20 that has not been cut.
In addition, the assist gas that blows the assist gas 90 onto the portion of the planned cutting line 20 (coaxial with the laser light L) at least when the laser beam L is irradiated onto the planned cutting line 20 of the substrate 10 in the forward path cutting process and the backward path cutting process. A spraying process can be performed.
In addition, at least when the laser beam L is applied to the planned cutting line 20 of the substrate 10 and when the assist gas 90 is supplied in the above-described forward path cutting process and backward path cutting process, the processing dust discharge means 54 sucks and discharges the processing dust 80. Can be performed.
At this time, the processing scattered matter discharging means 54 can suck and discharge the processing scattered matter 80 from the suction discharge port 55b.

  That is, according to the present invention, the forward path cutting process is performed along all the planned cutting lines 20 set on the substrate 10, and then the return path is performed along all the planned cutting lines 20 that have undergone the forward path cutting process. By performing the cutting step, each section 30 in the substrate 10 can be cut and separated separately.

Further, as described above, when the laser beam L is irradiated from the laser processing head 55 to the laser processing site of the workpiece W, the assist gas 90 can be sprayed and supplied to the laser processing site of the workpiece W. . At this time, in the forward path cutting step, the assist gas and the laser beam are allowed to escape together through the forward path cutting portion 60a (long hole) whose length is being extended by laser cutting.
At this time, since the assist gas flows from the laser processing head 55 at a narrow interval (near the center position C) between the sealing bodies 40 on the workpiece W (substrate 10) first, It becomes difficult for the assist gas including the processing scattered matter 80 generated by the laser cutting to pass through the narrow space between the sealing bodies 40 and easily flows to the opposite side to the laser cutting direction [(2) in FIG. The assist gas including the processed scattered matter 80 passes through the forward path cutting portion 60a. For this reason, the effective range (space part) of the assist gas is formed in the vicinity of the upper position of the forward cutting section 60a in the section 60 of the workpiece W (substrate) (in the vicinity of the lower position of the laser processing head 55). Become.
Also, in the above-described return path cutting step, the assist gas and the laser beam are combined together in the return path cutting portion 70a (long hole) whose length has been extended by laser cutting, as in the forward path cutting process. It will come out.
At this time, the assist gas bounces off when hitting the sealing body 40, and the bounced assist gas flows to the opposite side to the laser cutting direction and passes through the return path cutting portion 70a. For this reason, the effect range (space part) of the assist gas is formed in the vicinity of the upper position of the return cutting section 70a in the section 70 of the workpiece W (substrate) (in the vicinity of the lower position of the laser processing head 55). Become.

Further, according to the present invention, as shown in FIG. 3, first, when laser processing is performed in the section 60 from the position 30a on the start end side to the center position C in each section 30 in the forward path cutting step, the assist gas 90 is obtained. And the processing scattered matter 80 captured thereby flows in the direction opposite to the scanning direction of the laser beam L (upward in the figure) (see FIG. 3 (2)).
Accordingly, the assist gas 90 and the scattered work 80 captured by the assist gas 90 flow in a direction away from the transparent resin lens body 40 projecting on both sides of the planned cutting line 20 (in the direction of the upper start side position 30a). Therefore, it is possible to prevent or suppress the action of these colliding or adhering to the transparent resin lens body 40.
As shown in FIG. 4, the substrate 10 that has undergone the forward cutting step is formed with the forward cutting portions 60a in the respective sections 60.

Next, as shown in FIG. 5, in the above-described return path cutting step, the laser beam L extends from a position 30b on the end side in the section 30 of the final row of the planned cutting line 20 to its center position C in the section 31 of the first row. When the laser beam machining is performed on each section 70 of the cutting line 20 that is not cut during this period, the assist gas 90 and the processing scattered matter 80 captured thereby are opposite to the scanning direction of the laser beam L ( In the figure, it flows downward) (see Fig. 5 (2)).
Therefore, basically, the assist gas 90 and the scattered work 80 captured by the assist gas 90 are away from the transparent resin lens body 40 projecting on both sides of the planned cutting line 20 (the direction of the lower starting end side position 30a). ) To prevent or suppress the action of collision or adhesion to the transparent resin lens body 40.
Further, as shown in FIG. 6, the substrate 10 that has undergone the return path cutting step is formed with a return path cutting portion 70a in each section 70 thereof.
That is, the substrate 10 can be cut along the planned cutting line 20 by performing the forward path cutting process at the planned cutting line 20 and the return path cutting process at the planned cutting line 20.

Further, in the above-described return path cutting step, although it is estimated, the assist gas including the processing scattered material 8 flows into the forward path cutting section 60a at the front position (section 60) of the section 70 of the planned cutting line 20 in the laser scanning direction. It is estimated that the substrate can be removed from the front side to the back side.
For this reason, in the above-described return path cutting step, the discharge of the processed scattered matter 80 to the outside of the substrate surface causes the assist gas 90 including the processed scattered matter 80 to flow in the direction opposite to the scanning direction of the laser light L. In addition, it is possible to use in combination with the action of causing the assist gas 90 including the processing scattered matter 80 to flow into the forward path cutting portion 60a.

As described above, the laser beam L irradiation in the forward path cutting process and the backward path cutting process does not continuously perform all sections (each section 60 and each section 70) of the planned cutting line 20.
That is, the laser light L irradiation is performed intermittently only in the sections 60 and 70 in the planned cutting line 20, and the laser light L irradiation in the sections is performed up to the center position C of each section 30. The operation is not performed beyond the center position C.
Therefore, as in the case of conventional laser light irradiation that continuously irradiates the entire section of the planned cutting line, a large amount of processing scattered matter (80) is present at the position that has passed the center position (C) of each section (30). By colliding or adhering, it is possible to efficiently prevent the occurrence of a portion (see reference numeral 9 in FIG. 7) where the surface easily burns or is damaged.

The laser beam L irradiation in the forward path cutting process and the backward path cutting process described above does not continuously perform all sections (each section 60 and each section 70) of the planned cutting line 20, but the laser beam in the backward path cutting process For L irradiation, this may be performed continuously.
As described above, in each section 60 of the planned cutting line 20, in the forward path cutting step, the forward path cutting portion 60a has already been formed and has been cut. Therefore, in the return path cutting step, it is only necessary to perform laser beam L irradiation only on each section 70 of the planned cutting line 20 that has not yet been cut to form the return path cutting portions 70a.
That is, in the return path cutting step, it is only necessary to perform intermittent laser processing on each section 70 that is not cut. For example, the position on the terminal side in the section 30 of the last row of the planned cutting line 20 You may make it irradiate continuously the laser beam L with respect to all the sections from 30b to the starting end side position 30a in the section 31 of the 1st row (refer to Drawing 2 (2)).
In this case, since each section 60 of the planned cutting line 20 has already been cut, only the respective sections 70 of the planned cutting line 20 are laser processed.
Further, even if the laser beam L irradiation is continuously performed in the return path cutting step, the laser processing of each section 60 in the planned cutting line 20 is not performed. Therefore, the laser processing is not performed beyond the center position C of each section 30.
For this reason, a part where a large amount of processed scattered matter 80 collides or adheres to the position passing through the center position C of each section 30 as described above and the surface thereof is easily burnt or damaged (see reference numeral 9 in FIG. 7). Will not occur.

  In addition, each of the sections 30 in the substrate 10 can be cut and separated separately by performing the above-described forward cutting step and the backward cutting step along each grid-like cutting line 20 set on the surface of the substrate 10. Can do.

  In addition, at least when the laser beam L is irradiated and when the assist gas 90 is supplied in the above-described forward path cutting process and the backward path cutting process, the processing scattered from the portion of the planned cutting line 20 (laser processing portion) via the processing scattered matter discharging means The scattered matter 80 is put on the flow of the assist gas 90 and sucked outside to be discharged, so that the processed scattered matter 80 collides with or adheres to the transparent resin lens body 40 and burns or damages the transparent resin lens body 40. The action can be prevented more efficiently.

FIG. 2 schematically shows a state in which a dissolved material remains on the back surface of the substrate 10 during the thermal processing by the laser.
The molten residue (dross) 81 adhering to the back surface of the substrate is prevented from adhering to the back surface of the substrate by adjusting the flow rate or pressure of the assist gas 90 (see FIG. 1) flowing coaxially with the laser beam L. It is possible.

The present invention is not limited to the above-described embodiments, and can be arbitrarily changed and selected as necessary within a range not departing from the gist of the present invention.
For example, in laser processing, so-called CW laser processing by CW oscillation (continuous oscillation) or pulse laser processing by pulse oscillation may be employed.

In the present invention, although not shown in the drawing, air is forcibly sucked and discharged to the suction table 51 side which is the lower surface of the workpiece W (substrate) (non-lens body forming surface of the substrate). A suction discharge means can be provided in an auxiliary manner.
That is, the inside of the forward cut section 60a (long hole) in the section 60 formed in the workpiece W (substrate) by laser cutting processing or the inside of the backward cut section 70a (long hole) in the section 70 is transferred to the substrate 10. From the upper surface side (the semiconductor device sealing body forming surface side of the substrate or the laser light irradiation side) to the lower surface side of the substrate (the non-semiconductor device sealing body forming surface side of the substrate or the side opposite to the laser light irradiation side) The air can be forcibly sucked and discharged. For this reason, the assist gas 90 including the work scattering object 80 is generated from the forward cutting part 60a of the workpiece W (substrate) or from the backward cutting part 70a of the workpiece W (substrate) by the forced suction discharge means. It can be discharged from the surface of the substrate to the outside.

10 Board
10a Processing scattered matter
20 Scheduled cutting line
30 compartments
30a Start end position
30b Terminal position
31 First row compartment
32 Second row compartment
40 Transparent resin lens body
50 Laser processing section
51 Suction table
51a Suction pad
52 Laser beam irradiation means
53 Assist gas supply means
54 Means for discharging processed waste
55 Laser processing head
55a opening
55b Suction outlet
60 segments
60a Outward cutting section
70 segments
70a Return cut section
80 Processing scattered matter
81 Molten residue
90 Assist gas C Center position L Laser beam S Interval W Workpiece

Claims (4)

By mounting and sealing a semiconductor device in a number of sections in which grid-like cutting lines are set on the surface of the substrate, there is a difference in height between the height of the substrate surface and the height of the semiconductor device sealing body. A laser processing method for cutting and separating the substrate for each of the sections by irradiating the workpiece with laser light along the planned cutting line,
The laser beam is irradiated from the position on the start end side to the center position of the first row section along the planned cutting line of the substrate to cut the section of the planned cutting line, and the first row section The irradiation of the laser beam is stopped from the center position in the second row section to the position on the start end side so as not to cut the section of the planned cutting line, and further to the last row section as described above. By repeatedly irradiating and stopping the laser beam on the planned cutting line, each of the planned cutting lines is irradiated with laser light from the position on the start end side in the section of each row along the planned cutting line to the center position thereof. An outward cutting process for cutting the section;
The cutting schedule which is an uncut portion in the meantime by irradiating a laser beam from the position on the terminal side of the final row section of the planned cutting line that has undergone the forward cutting process to the center position of the first row section A return path cutting step for cutting each section of the line;
An assist gas spraying step of spraying and supplying an assist gas to a portion of the planned cutting line at the time of laser beam irradiation to at least the planned cutting line of the substrate in the forward path cutting step and the backward path cutting step;
Further, the forward cutting step is performed along each planned cutting line of the substrate, and then each of the sections on the substrate is separately performed by performing the backward cutting process of the planned cutting line that has undergone the forward cutting process. A laser processing method characterized by cutting and separating.   The laser processing method according to claim 1, wherein the semiconductor device is formed by sealing an optical semiconductor element into a sealing body made of a transparent resin lens body.   In the assist gas spraying step, the suction gas discharging step of sucking and discharging the assist gas sprayed to the site of the planned cutting line and the processing scattered matter generated from the site of the planned cutting line is performed. Item 2. The laser processing method according to Item 1. Assist gas sprayed on the portion of the planned cutting line by forcibly discharging air from the laser beam irradiation side to the opposite side in the forward cutting section formed along the planned cutting line in the forward cutting step And a step of discharging the processing scattered matter generated from the part of the planned cutting line,
2. The step of forcibly discharging air from the laser beam irradiation side to the opposite side is performed in the return path cutting portion formed along the planned cutting line in the return path cutting step. Laser processing method.

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