KR20190029453A - Method of manufacturing a light emitting element - Google Patents

Abstract

The present invention provides a light emitting element manufacturing method capable of improving production efficiency. A method of manufacturing a light emitting element includes: irradiating a substrate of a wafer having the substrate and a semiconductor structure with a laser beam to form a plurality of modified regions in the substrate; and subsequently, separating the wafer into a plurality of light emitting elements. The step of irradiating the substrate with a laser beam includes a first irradiation step of irradiating the laser beam along a plurality of first lines. The first lines extend in a first direction that is parallel to a first face and are aligned in a second direction that is parallel to the first face and intersects the first direction. The step of irradiating the substrate with a laser beam includes a second irradiation step of irradiating the laser beam along second lines that extend in the second direction, after the first irradiation step. In the first irradiation step, a plurality of positions along the first direction are irradiated with the laser beam, in which a first irradiation pitch of the plurality of positions is 2.5 μm or less and a pitch of the first lines in the second direction is at least 0.7 mm.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a light emitting device,

The present invention relates to a method of manufacturing a light emitting device.

In a method of manufacturing a light emitting device in which a compound semiconductor functioning as a light emitting layer is laminated on a substrate, there has been proposed a method of forming a device dividing line by laser irradiation of a substrate. In the method for manufacturing a light emitting device, improvement in productivity is required.

Japanese Patent No. 5119463

The present invention provides a method of manufacturing a light emitting device capable of improving productivity.

According to one aspect of the present invention, there is provided a method of manufacturing a light emitting device, comprising the steps of: irradiating laser light onto a substrate having a first surface and a second surface and a wafer including a semiconductor structure provided on the second surface; A laser light irradiation step of forming a plurality of modified regions in the substrate and a separation step of separating the wafer into a plurality of light emitting elements after the laser light irradiation step. The laser light irradiation step includes a first irradiation step of scanning the laser light along a plurality of first lines. The plurality of first lines extend in a first direction parallel to the first surface, and are arranged in a second direction parallel to the first surface and intersecting the first direction. The laser irradiation step includes a second irradiation step of scanning the laser beam along a second line extending in the second direction after the first irradiation step. Wherein the first irradiation step irradiates the laser light at a plurality of positions along the first direction, the first irradiation pitch of the plurality of positions along the first direction is not more than 2.5 mu m, The pitch of the first line in the second direction is 0.7 mm or more.

According to an aspect of the present invention, a method of manufacturing a light emitting device capable of improving productivity is provided.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flow chart illustrating a method of manufacturing a light emitting device according to an embodiment;
2 is a schematic diagram illustrating a wafer used in a method of manufacturing a light emitting device according to an embodiment.
3 is a schematic view illustrating a wafer used in a method of manufacturing a light emitting device according to an embodiment.
4 is a schematic view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.
5 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.
6 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.
7 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.
8 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.
9 is a schematic cross-sectional view illustrating a part of a method of manufacturing a light emitting device.
10 is a graph illustrating an experimental result of a method of manufacturing a light emitting device.
11 is a microphotograph image illustrating an experimental result on a manufacturing method of a light emitting device.
12 is a microphotograph image illustrating an experimental result on a manufacturing method of a light emitting device.
13 is a schematic diagram illustrating experimental results on a method of manufacturing a light emitting device.
14 is a schematic view illustrating a part of another manufacturing method of the light emitting device according to the embodiment.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

In addition, the drawings are schematic or conceptual, and the relationship between the thickness and the width of each portion, the ratio between the sizes of the portions, and the like are not necessarily the same as those in reality. Further, even when the same portions are shown, the dimensions and ratios of the portions may be different from each other depending on the drawings.

In the description of the present invention, the same elements as those described above in the drawings already described are denoted by the same reference numerals, and a detailed description thereof will be appropriately omitted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart illustrating a method of manufacturing a light emitting device according to an embodiment;

Fig. 2 and Fig. 3 are schematic views illustrating a wafer used in the method of manufacturing a light emitting device according to the embodiment. Fig. 2 is a sectional view taken along the line II-II in Fig. 3. Fig. 3 is a plan view seen from the arrow AR in Fig.

As shown in Fig. 1, the manufacturing method of a light emitting device according to the embodiment includes a laser light irradiation step (step S110) and a separation step (step S120). The laser light irradiation step includes a first irradiation step (step S111) and a second irradiation step (step S112). The separation step includes a first separation step (step S121) and a second separation step (step S122).

In the laser irradiation process, the wafer is irradiated with laser light. Hereinafter, an example of a wafer will be described.

As shown in Figs. 2 and 3, the wafer 50W includes a substrate 50 and a semiconductor structure 51. Fig. The substrate 50 has a first surface 50a and a second surface 50b. The second surface 50b is a surface opposite to the first surface 50a. The semiconductor structure 51 is provided, for example, on the second surface 50b.

The semiconductor structure 51 includes, for example, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer. An n-type semiconductor layer is located between the p-type semiconductor layer and the substrate 50. An active layer is located between the p-type semiconductor layer and the n-type semiconductor layer. The semiconductor structure 51 includes, for example, a nitride semiconductor such as In _x Al _y Ga _{1 -x- y} N (0? X, 0? Y, x + y <1) The peak wavelength of the light emitted by the active layer is, for example, 360 nm or more and 650 nm or less.

And the direction from the second surface 50b toward the first surface 50a is the Z-axis direction. One direction perpendicular to the Z-axis direction is the X-axis direction. And the direction perpendicular to the Z-axis direction and the X-axis direction is the Y-axis direction. The first surface 50a and the second surface 50b extend along the X-Y plane. The Z-axis direction corresponds to the thickness direction (for example, depth direction) of the substrate 50.

As shown in Fig. 3, the semiconductor structure 51 includes, for example, a plurality of regions 51r. Each of the plurality of regions 51r corresponds to one light emitting element. The plurality of regions 51r are arranged in the first direction D1 and the second direction D2.

The first direction D1 is one direction parallel to the first surface 50a. The second direction D2 is parallel to the first surface 50a and intersects the first direction D1. The second direction D2 is, for example, perpendicular to the first direction D1. In this example, the first direction D1 follows the X-axis direction. The second direction D2 follows the Y-axis direction.

The substrate 50 is made of, for example, sapphire. The substrate 50 is, for example, a sapphire substrate (for example, a c-plane sapphire substrate). In the substrate 50, the first surface 50a may be inclined with respect to the c-plane. In the case where the substrate 50 is a sapphire substrate, in one example, the first direction D1 follows the m axis of the sapphire substrate. At this time, the second direction D2 follows the a axis of the sapphire substrate.

The substrate 50 has an orientation flat 55. In this example, the extending direction of the orientation flat 55 is along the first direction D1 of the wafer 50W. In the embodiment, the relationship between the first direction D1 and the extending direction of the orientation flat 55 is arbitrary. The relationship between the second direction D2 and the extending direction of the orientation flat 55 is arbitrary.

Such a wafer 50W is irradiated with laser light. The wafer 50W is separated along the boundary of the plurality of regions 51r. A plurality of light emitting elements are obtained from the plurality of regions 51r.

4 is a schematic diagram illustrating a part of a manufacturing method of a light emitting device according to an embodiment.

Fig. 4 illustrates irradiation of laser light. As shown in Fig. 4, the substrate 50 of the wafer 50W is irradiated with a laser beam 61. Fig. In this example, the laser light 61 is incident on the substrate 50 from the first surface 50a.

The laser light 61 is emitted in a pulse-like fashion. As the laser light source, for example, an Nd: YAG laser, a titanium sapphire laser, an Nd: YVO ₄ laser, or an Nd: YLF laser is used. The wavelength of the laser light 61 is the wavelength of the light transmitted through the substrate 50. The laser light 61 is, for example, laser light having a peak wavelength in the range of 800 nm to 1200 nm.

The laser light 61 is scanned along a direction parallel to the X-Y plane. For example, the relative positions of the laser light 61 and the substrate 50 are changed along a direction parallel to the X-Y plane. The position along the Z axis direction of the light-converging point of the laser light 61 (the position with respect to the substrate 50) may be changed.

For example, along one direction along the first surface 50a of the substrate 50, the laser light 61 is irradiated discretely. The plurality of positions irradiated with the laser light 61 are apart from each other along one direction. The plurality of positions irradiated with the laser light 61 are arranged at one pitch (laser irradiation pitch Lp). The laser irradiation pitch Lp corresponds to the pitch between the shots of the laser light 61. [

A plurality of modified regions 53 are formed in the substrate 50 by the irradiation of the laser light 61. The laser beam 61 is condensed in the substrate 50. The energy by the laser beam 61 is concentrated at a position of a specific depth in the substrate 50. Thereby, a plurality of modified regions 53 are formed. The pitch of the light-converging points of the laser light 61 when forming the plurality of modified regions 53 corresponds to the laser irradiation pitch Lp. The modified region 53 is, for example, a region inside the substrate 50 which is brittle by laser irradiation.

From the plurality of modified regions 53, for example, cracks develop. The crack extends in the Z-axis direction of the substrate 50. The crack becomes the start position of separation of the substrate 50. For example, force (e.g., load, impact, etc.) is applied in the separation process described below. Thereby, based on the crack, the substrate 50 is separated.

As described above, in the laser light irradiation step (step S110), a plurality of modified regions 53 are formed in the substrate 50 by irradiating the substrate 50 with the laser light 61. [ Laser irradiation is performed along, for example, the first direction D1 and the second direction D2.

Then, in the separation step (step S120), the wafer 50W is separated into a plurality of light emitting elements after the laser light irradiation step. For example, by performing separation along two directions, the wafer 50W is separated into a plurality of light emitting elements.

Hereinafter, an example of the laser light irradiation step will be described.

5 is a schematic plan view illustrating a part of a manufacturing method of the light emitting device according to the embodiment.

Fig. 5 illustrates a first irradiation step (step S111). As shown in Fig. 5, in the first irradiation step, laser light 61 is scanned along a plurality of first lines L1.

The plurality of first lines L1 extend in the first direction D1 and are arranged in the second direction D2. As already described, the first direction D1 is parallel to the first surface 50a. The second direction D2 is parallel to the first surface 50a and intersects the first direction D1. A plurality of first lines L1 are arranged at a first pitch P1. The first pitch P1 is a distance along the second direction D2 between the two adjacent first lines L1 in the second direction D2. In the embodiment, the first pitch P1 is 0.7 mm or more, for example. The first pitch P1 is preferably 0.7 mm or more and 3 mm or less, more preferably 0.9 mm or more and 2.5 mm or less, and still more preferably 1 mm or more and 2 mm or less.

The plurality of first lines L1 follow the boundary between a plurality of regions 51r (see FIG. 3) arranged in, for example, the second direction D2.

As shown in Fig. 5, in the irradiation of the laser light 61 along one of the plurality of first lines L1, the laser light 61 is irradiated to the plurality of first positions 61a. The plurality of first positions 61a are arranged along the first direction D1. The pitch of the plurality of first positions 61a corresponds to the first irradiation pitch Lp1. In the first irradiation pitch Lp1, the two first positions 61a adjacent to each other in the first direction D1 are along the first direction D1.

The first irradiation pitch Lp1 is, for example, 2.5 占 퐉 or less, preferably 2.0 占 퐉 or less, and more preferably 1.5 占 퐉 or less.

6 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to the embodiment.

Fig. 6 illustrates a second irradiation step (step S112). As shown in Fig. 6, in the second irradiation step, laser light 61 is scanned along a plurality of second lines L2.

The plurality of second lines L2 extend in the second direction D2. The plurality of second lines L2 are arranged at the second pitch P2 in the first direction D1. The second pitch P2 is a distance along the first direction D1 between the two adjacent second lines L2 in the first direction D1.

The plurality of second lines L2 follow a boundary between a plurality of regions 51r (see FIG. 3) arranged in, for example, the first direction D1.

The laser light 61 is irradiated to the plurality of second positions 61b in irradiation of the laser light 61 along one of the plurality of second lines L2 in the second irradiation step. The plurality of second positions 61b are arranged along the second direction D2. The pitch of the plurality of second positions 61b corresponds to the second irradiation pitch Lp2. The second irradiation pitch Lp2 is such that the two second positions 61b adjacent to each other in the second direction D2 follow the second direction D2.

In one example, the first irradiation pitch Lp1 is smaller than the second irradiation pitch Lp2.

In one example, the first pitch P1 (see FIG. 5) is smaller than the second pitch P2 (see FIG. 6). The first pitch P1 may be larger than the second pitch P2 or the first pitch P1 and the second pitch P2 may be equal to each other.

Hereinafter, an example of the separation process will be described.

7 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to an embodiment.

Fig. 7 illustrates a first separation step. In the first separation step, the wafer 50W is separated into a plurality of bars 52 (bars) along a plurality of first lines L1. For example, by using a blade, the wafer 50W is separated into a plurality of bars 52 by applying a load to the wafer 50W along the first line L1. In the embodiment, one bar 52 is in a state in which a plurality of regions 51r are arranged in the first direction D1.

8 is a schematic plan view illustrating a part of a manufacturing method of a light emitting device according to the embodiment.

Fig. 8 illustrates a second separation step. The second separation step is performed after the first separation step. The second separation step separates the bar 52 into a plurality of light emitting elements 51e along the plurality of second lines L2 after the first separation step. For example, by using a blade, the bar 52 is separated into the plurality of light emitting elements 51e by applying the load to the bar 52 (wafer 50W) along the second direction D2.

The separation is performed by, for example, splitting.

As already described, in one example, the first pitch P1 is smaller than the second pitch P2. In one of the plurality of light emitting devices 51e obtained by the above manufacturing method, the length along the first direction D1 is longer than the length along the second direction D2. One of the plurality of light emitting elements 51e has a long side and a short side. The length of the long side substantially corresponds to the second pitch P2. The length of the short side corresponds to the first pitch P1.

As described above, in the laser light irradiation step, the first irradiation step (step S111) and the second irradiation step (step S112) are performed. It has been found that when the second irradiation step is performed after the first irradiation step, the laser beam 61 is irradiated onto the substrate 50 (wafer 50W) in a state where it is not desired. Hereinafter, this example will be described.

9 is a schematic cross-sectional view illustrating a part of a manufacturing method of a light emitting element.

Fig. 9 illustrates irradiation states of the substrate 50 and the laser beam 61 when the second irradiation step is performed after the first irradiation step. In this example, the first irradiation step was not performed under appropriate conditions.

As shown in Fig. 9, laser light 61 is irradiated along the first line L1 in the first irradiation step. As a result, a plurality of modified regions 53a are formed in the substrate 50. In Fig. 9, a cross section based on a plane including the second direction D2 and the Z-axis direction is shown. Therefore, one of the plurality of modified regions 53a is shown. The plurality of modified regions 53a are arranged along the first direction D1.

A plurality of modified regions 53a are formed on the substrate 50 and a crack CR is generated in the substrate 50 when the irradiation conditions of the laser light 61 are appropriate, For example, the first surface 50a) are continuous and one plane. That is, only by irradiating the laser beam 61, the substrate 50 is not separated from the crack CR as a starting point. The crack (CR) is generated starting from a plurality of modified regions (53).

On the other hand, when the irradiation conditions of the laser light 61 are inappropriate, a plurality of modified regions 53a are formed on the substrate 50, and a crack (CR) is generated in the substrate 50. [ The first surface 50a of the substrate 50 is separated by the crack CR with the first line L1 as a boundary. The two first faces 50a formed separately are not continuous. The two first surfaces 50a are inclined with respect to each other. In this manner, when the irradiation condition of the laser light 61 is inappropriate, unintentional &quot; cracking &quot; occurs in the substrate 50.

By this unintended &quot; cracking &quot;, the first surface 50a of the substrate 50 becomes uneven. By &quot; cracking &quot;, the first surface 50a is inclined. In this state, when the second irradiation step is carried out, the depth position of the light-converging point of the laser light 61 in the substrate 50 is not constant. Therefore, the depth positions of the plurality of modified regions 53b formed in the second irradiation step are not constant.

As shown in Fig. 9, for example, in the region close to the crack CR, the position of the modified region 53b is deep. On the other hand, in the region far from the crack CR, the position of the modified region 53b is shallow. For this reason, it is difficult to carry out the separation (second separation step) based on the second irradiation step in a desired state. For example, defects tend to occur, and product yield tends to be lowered, making it difficult to increase the productivity sufficiently. In the region close to the crack CR, the position where the laser beam 61 is condensed is close to the semiconductor structure 51. For this reason, damage by the laser beam 61 occurs in the semiconductor structure 51.

As described above, if the condition of the first irradiation step is inappropriate, unintended &quot; cracking &quot; occurs, and as a result, it has been found that it becomes difficult to carry out the second irradiation step under appropriate conditions.

In the embodiment, the conditions of the first irradiation step are made appropriate. Thus, for example, unintended &quot; cracking &quot; can be suppressed. Thereby, the second irradiation step can be carried out under appropriate conditions. It is possible to provide a method of manufacturing a light emitting device capable of improving productivity.

Hereinafter, experimental results concerning conditions of the first irradiation step will be described.

In the experiment, a sapphire substrate having a thickness of 200 탆 was used as the substrate 50. The plane shape of the sample is a square having a side length of 10.2 mm. A laser beam 61 whose irradiation condition was changed was irradiated to the center of the sample. The laser light 61 was irradiated along the m-axis of the sapphire substrate. After irradiation of the laser light 61, the breaking strength of the sample was measured. In measuring the breaking strength, the pressing speed of the head applied to the sample is 0.05 mm / sec.

In the sample SP11, the power of the laser beam 61 is 3.5 占 이며, and the laser irradiation pitch Lp is 1.5 占 퐉. In the sample SP11, the laser pulse width is 5.0 ps.

In the sample SP12, the power of the laser beam 61 is 3.5 占 이며, and the laser irradiation pitch Lp is 2.0 占 퐉. In the sample SP12, the laser pulse width is 5.0 ps.

In the sample SP13, the power of the laser beam 61 is 3.5 占,, and the laser irradiation pitch Lp is 2.5 占 퐉. In the sample SP13, the laser pulse width is 5.0 ps.

In the sample SP14, the power of the laser beam 61 is 3.5 占 이며, and the laser irradiation pitch Lp is 3.0 占 퐉. In the sample SP14, the laser pulse width is 5.0 ps.

Thus, in the samples SP11 to SP14, the power and the laser pulse width are the same among the irradiation conditions of the laser beam 61, and the value of the laser irradiation pitch is changed.

Fig. 10 is a graph showing an experimental result on a manufacturing method of a light-emitting element.

10 is the breaking strength N1 (Newton: N). Fig. 10 shows the breaking strength N1 of the samples SP11 to SP14. The fracture strength N1 of the samples SP11 to SP14 shown in Fig. 10 is measured three times for each of the samples SP11 to SP14, and is an average value of the values obtained by these measurements. The fracture strength N1 in the specimen SP11 was 3.8N. The fracture strength N1 in the sample SP12 was 2.3 N. The fracture strength N1 in the sample SP13 was 1.6N. The fracture strength N1 in the sample SP14 was 0.6N.

As can be seen from Fig. 10, the breaking strength N1 largely depends on the laser irradiation pitch Lp. By reducing the laser irradiation pitch Lp, a high breaking strength N1 can be obtained. In this experiment, the laser light 61 is irradiated along the m-axis of the sapphire substrate. For example, even when the laser beam 61 is irradiated along the a-axis of the sapphire substrate, the same result as in Fig. 10 can be obtained.

For example, when the fracture strength N1 is relatively small as in the sample SP14, unexpected "cracking" occurs in the substrate 50 after the first irradiation step. On the other hand, when the breaking strength N1 is high, it is possible to suppress the occurrence of unintended &quot; cracks &quot; in the substrate 50 after the first irradiation step.

By making the laser irradiation pitch Lp small, a high breaking strength N1 can be obtained. For example, when the laser irradiation pitch Lp is 1.5 탆 or less, a fracture strength N1 higher than 3.8 N can be obtained. It is possible to further suppress the occurrence of unintended &quot; cracks &quot; in the substrate 50 after the first irradiation step.

When the laser irradiation pitch Lp is set to be larger than the predetermined value, cracks formed are difficult to be connected, and the substrate 50 tends to be difficult to be divided. For this reason, the inventors of the present invention have thought that the substrate 50 is easily divided by narrowing the laser irradiation pitch Lp. However, as described above, in practice, it has been found that, by narrowing the laser irradiation pitch Lp, the fracture strength N1 is increased, and unintended &quot; cracking &quot; of the substrate 50 is suppressed. The reason why the unintended &quot; cracking &quot; is suppressed is that a plurality of modified regions 53 are densely formed inside the substrate 50 on the scanning line of the laser light 61, This is because it is difficult to divide.

In the embodiment, the laser irradiation pitch Lp (i.e., the first irradiation pitch Lp1) in the first irradiation step is made small. For example, the first irradiation pitch Lp1 is 2.5 mu m or less. Thereby, a high breaking strength N1 can be obtained, and unintended &quot; cracking &quot; can be suppressed. As a result, for example, the irradiation state (depth of the light-converging point) of the laser light 61 in the second irradiation step is stabilized.

In the embodiment, the first irradiation pitch Lp1 is 1.0 占 퐉 or more. Thus, for example, it is possible to suppress the damage to the semiconductor structure 51 by laser light in the laser light irradiation step. Further, the time required for the laser light irradiation step can be prevented from being prolonged, and the productivity can be improved.

In the embodiment, for example, the first irradiation pitch Lp1 is preferably smaller than the second irradiation pitch Lp2. Thereby, unintended &quot; cracking &quot; after the first irradiation step can be suppressed.

For example, the second irradiation pitch Lp2 is 5.0 m or more and 12.0 m or less, preferably 5.0 m or more and 7.0 m or less. If the second irradiation pitch Lp2 is 5.0 占 퐉 or more, for example, the line which is a starting point of separation tends to be linear when the substrate is separated. When the second irradiation pitch Lp2 is 12.0 占 퐉 or less, for example, the cracks CR from the modified region 53 are prevented from being connected with each other, and the substrate 50 is easily separated .

As described above, in the embodiment, the first pitch P1 (the pitch of the plurality of first lines L1 in the second direction D2) is 0.7 mm or more. The first pitch P1 is preferably 0.7 mm or more and 3 mm or less, more preferably 0.9 mm or more and 2.5 mm or less, and still more preferably 1 mm or more and 2 mm or less. If the first pitch P1 is 0.7 mm or more, a relatively large force is applied to a portion of the substrate 50 where the modified region 53 is formed, and unintended &quot; cracking &quot; tends to occur. This is because if the wafer 50W has a warp caused by stress and the first pitch P1 becomes larger, the amount of warpage between adjacent first lines D1 becomes relatively large, and the warp caused by the warpage . As a result, unintended &quot; cracking &quot; tends to occur in the portion where the modified region 53 is formed, after the first irradiation step or during the first irradiation step. In the present embodiment, the first irradiation pitch Lp1 is narrowed. As a result, the breaking strength N1 is increased, and unintended &quot; cracking &quot; can be suppressed even when the first pitch P1 is relatively large.

As described above, it is preferable that the first irradiation pitch Lp1 is smaller than the second irradiation pitch Lp2. At this time, in one example, the first line L1 (first direction D1) follows the m axis, and the second line L2 (second direction D2) follows the a axis. In another example, the first line L1 (first direction D1) is along the a axis, and the second line L2 (second direction D2) is along the m axis. In another example, the first line L1 (first direction D1) may be inclined with respect to the a-axis, and the second line L2 (second direction D2) may be inclined with respect to the a-axis.

In the embodiment, it is particularly preferable that the first direction D1 (first line L1) along the m axis and the second direction D2 (second line L2) follow the a axis. This is because even if the laser irradiation pitch Lp (the first irradiation pitch Lp1) is reduced by scanning the laser light 61 along the m-axis as described below, As described later) is liable to be linear.

Hereinafter, examples of experimental results when the laser light 61 is scanned along the a axis will be described.

Figs. 11 and 12 are microscopic photographs illustrating experimental results on a method of manufacturing a light-emitting device.

These drawings show microscope photographs of the sample (SP21), the sample (SP22) and the sample (SP23). In these samples, the laser irradiation pitches Lp of the laser light 61 are different from each other. In these samples, the laser light 61 is scanned along the Y-axis direction. In this experiment, the Y axis direction follows the a axis of the sapphire substrate. The X-axis direction follows the m-axis of the sapphire substrate.

The laser irradiation pitch Lp in the sample SP21 is 12 占 퐉. The laser irradiation pitch Lp in the sample SP22 is 10 占 퐉. The laser irradiation pitch Lp in the sample SP23 is 8 占 퐉. In Fig. 11, the focus of the photograph is located at the depth of the modified region 53. Fig. In Fig. 12, the focus of the photograph is located on the surface (the first surface 50a in this example) of the substrate 50 (sapphire substrate).

As can be seen from Fig. 11, in the sample SP21 having a large laser irradiation pitch Lp, a line 53L for linearly connecting the plurality of modified regions 53 is observed. It is considered that this line 53L corresponds to the crack CR (or the origin of the crack CR). A line 53L for linearly connecting the modified region 53 is observed in a part of the plurality of modified regions 53 even in the sample SP22 having the laser irradiation pitch Lp of intermediate. However, this line 53L is bent as compared with the sample SP21. In the sample SP23 with a small laser irradiation pitch Lp, the line 53L connecting the plurality of modified regions 53 linearly is not substantially observed. In the sample SP23, a curved line 53X passing around the plurality of modified regions 53 is observed.

12, in the sample SP21 having the large laser irradiation pitch Lp on the surface (the first surface 50a) of the sapphire substrate, a clear line (for example, 53L) are observed. It is considered that this line 53L corresponds to the crack CR (or the origin of the crack CR). In the sample SP22 having the laser irradiation pitch Lp of about the middle, the linearity of the line 53L is lowered and a part of the line 53L is inclined with respect to the first direction D1. In the sample SP23 with a small laser irradiation pitch Lp, the line 53L becomes more obscured, and a part of the line 53L is greatly inclined with respect to the first direction D1.

Fig. 13 is a schematic diagram illustrating experimental results on a method of manufacturing a light emitting device.

13 schematically shows lines 53L and lines 53X in the substrate 50 estimated from the micrographs of Figs. 11 and 12. Fig.

As shown in Fig. 13, in the sample SP21 having a large laser irradiation pitch Lp, a line 53L connecting the lattice points 54 of the sapphire crystal along the second direction D2 is generated. In the sample SP23 with a small laser irradiation pitch Lp, a line 53X extending in the inclined direction with respect to the second direction D2 beyond the lattice point 54 of the crystal of sapphire in addition to the line 53L ). It is considered that a state intermediate between the specimen SP21 and the specimen SP23 is generated in the specimen SP22 having the middle laser irradiation pitch Lp.

Thus, when the laser irradiation pitch Lp is large, a line 53L connecting the lattice points 54 of the sapphire crystal along the second direction D2 is formed. On the other hand, when the laser irradiation pitch Lp is small, a line 53X extending in an inclined direction with respect to the second direction D2 is apt to occur. The line 53X has a linear shape meandering. When the meandering line 53X is generated, for example, when the substrate 50 is separated, the cut surface may not be straight.

As described above, in the case of irradiating the laser light 61 along the a axis, when the laser irradiation pitch Lp is reduced, a meandering line 53X is apt to occur. This is considered to be a phenomenon peculiar to hexagonal crystal.

On the other hand, in the case of irradiating the laser beam 61 along the m-axis, even when the laser irradiation pitch Lp is made small, the meandering line 53X is unlikely to occur.

From the above, in the embodiment, in the first irradiation step in which the laser irradiation pitch Lp is small, it is preferable that the laser light 61 is scanned along the m-axis instead of the a-axis. At this time, in the second irradiation step, the laser light 61 is preferably scanned along the a axis. Thereby, the laser irradiation pitch Lp can be reduced, and unintended &quot; cracking &quot; can be suppressed. Furthermore, occurrence of the meandering line 53X can be suppressed. As a result, it is possible to provide a method of manufacturing a light emitting device capable of further improving productivity.

In the embodiment, the output of the laser beam 61 in the first irradiation step and the second irradiation step is preferably 100 mW or more and 300 mW or less, and more preferably 100 mW or more and 150 mW or less. If the output is higher than 300 mW, for example, the semiconductor structure 51 (for example, the light emitting element 51 e) may be damaged. If the output is lower than 100 mW, for example, the modified region 53 becomes difficult to form, or the crack from the modified region 53 becomes difficult to expand. This makes it difficult to separate the substrate 50. When the output is 100 mW or more and 300 mW or less, for example, the semiconductor structure 51 can be easily prevented from being damaged while suppressing the damage.

14 is a schematic diagram illustrating a part of another manufacturing method of the light emitting device according to the embodiment.

Fig. 14 illustrates the irradiation of the laser light 61. Fig. In this example, the light-converging point of the laser light 61 is located at a plurality of depth positions of the substrate 50. For example, the laser light 61 is scanned a plurality of times to irradiate the substrate 50. For example, in a plurality of scans, the depth position of the light-converging point of the laser light 61 is changed. Thus, for example, a group of a plurality of modified regions 53 and a group of a plurality of modified regions 53A are formed. The position of the plurality of modified regions 53 in the Z-axis direction is different from the position of the plurality of modified regions 53A in the Z-axis direction.

Thus, in the first irradiation step, the laser light 61 may be irradiated to a plurality of positions in the depth direction (Z-axis direction) from the first surface 50a to the second surface 50b. Thus, for example, generation of the meandering line 53X can be suppressed more stably.

According to the embodiments, it is possible to provide a method of manufacturing a light emitting device that can improve productivity.

In the present specification, the terms &quot; vertical &quot; and &quot; parallel &quot; are not limited to strict vertical and strict parallelism but include, for example, deviation in a manufacturing process, and may be substantially vertical and substantially parallel.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, as for the specific constitution of the wafer, the substrate, the semiconductor structure, the light emitting element, and the laser used in the manufacturing method of the light emitting element, the present invention is similarly carried out by appropriately selecting from the known range of those skilled in the art, Is included in the scope of the present invention as long as the effect of the present invention can be obtained.

It is also within the scope of the present invention to incorporate any two or more elements from the respective embodiments into a technically feasible range so long as the gist of the present invention is included.

In addition, all the light emitting device manufacturing methods that can be appropriately designed and carried out by those skilled in the art on the basis of the above-described manufacturing method of the light emitting device as the embodiment of the present invention, It belongs to the scope.

It should be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

50: substrate
50W: wafer
50a: first side
50b: second side
51: Semiconductor structure
51e: light emitting element
51r: area
52: bar
53, 53A: modified region
53L, 53X: line
53a and 53b:
54: grid point
55: Orientation Flat
61: laser light
61a, 61b: first and second positions
AR: Arrow
CR: Crack
D1, D2: first and second directions
L1, L2: first and second lines
Lp: laser irradiation pitch
Lp1, Lp2: First and second irradiation pitches
N1: Breaking Strength
P1, P2: first and second pitches
SP11 to SP14, SP21 to SP23:

Claims (6)

A method of manufacturing a light emitting device,
A laser light irradiation step of irradiating the substrate of the wafer including the semiconductor structure provided on the second surface with laser light to form a plurality of modified areas inside the substrate, ,
A separation step of separating the wafer into a plurality of light emitting elements after the laser light irradiation step
And,
In the laser light irradiation step,
A first irradiation step of scanning the laser light along a plurality of first lines, wherein the plurality of first lines extend in a first direction parallel to the first surface, parallel to the first surface, A first irradiation step arranged in a second direction intersecting with one direction,
A second irradiation step of scanning the laser beam along a second line extending in the second direction after the first irradiation step
/ RTI &gt;
In the first irradiation step,
Wherein the laser light is irradiated to a plurality of positions along the first direction, the first irradiation pitch of the plurality of positions along the first direction is 2.5 占 퐉 or less,
Wherein the pitch of the plurality of first lines in the second direction is 0.7 mm or more,
A method of manufacturing a light emitting device. The method according to claim 1,
Wherein the substrate is made of sapphire,
The first direction being along the m axis of the sapphire,
The second direction is along the a axis of the sapphire,
In the second irradiation step, the laser light is irradiated to a plurality of positions along the second direction, and the second irradiation pitch of the plurality of positions along the second direction is larger than the first irradiation pitch , A method of manufacturing a light emitting device. 3. The method of claim 2,
And the second surface is the c-plane of the sapphire. The method according to claim 2 or 3,
And the second irradiation pitch is 5.0 占 퐉 or more and 12.0 占 퐉 or less. 5. The method according to any one of claims 1 to 4,
Wherein the output of the laser light in the first irradiation step and the second irradiation step is 100 mW or more and 300 mW or less. 6. The method according to any one of claims 1 to 5,
Wherein the laser light is irradiated to a plurality of positions in a depth direction from the first surface to the second surface in the first irradiation step.

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