JP3534647B2 - Method for manufacturing semiconductor light emitting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor light emitting device which separates a semiconductor wafer by mechanical cutting and takes out light emission output from one of the cut surfaces.

[0002]

2. Description of the Related Art Conventionally, a light emitting diode (hereinafter referred to as "LE
Semiconductor light emitting devices such as D) are formed on a semiconductor wafer at the same time, electrodes are formed on both sides of the wafer, and then individual semiconductor light emitting devices are formed by mechanical cutting processing such as dicing or scribing. It is manufactured by dividing the chip. The divided semiconductor light emitting elements are roughly classified into a vertical mounting type in which only one surface of the wafer is in contact with the electrical wiring board and a horizontal mounting type in which both surfaces of the wafer are in contact with the electrical wiring board, depending on the mounting method on the electrical wiring board or the like. .

FIG. 7 shows a mounting state of the vertical type shown as FIG. 1 of Japanese Patent Publication No. 56-44591. Conductor 3 connected to external lead 2 on the main surface of electrically insulating base 1
Are formed in a predetermined pattern. Semiconductor light emitting element 4
The electrode 5 formed on the surface of the conductor 3 and the brazing layer 6
It is electrically joined by. The electrode 5 is also provided on the side facing the electrode 5 joined to the conductor 3 with the brazing layer 6,
The thin wire 7 is electrically connected to the conductor 3 by wire bonding.

In the vertical type semiconductor light emitting device 4 as shown in FIG. 7, in order to improve the reliability of wire bonding by the thin wire 7, the thin wire 7 connects the electrode 5 and the conductor 3 linearly. Rather, they need to be connected to form a loop. Therefore, a height for forming a loop is required, which is an obstacle to thinning.

FIG. 8 shows an outline of a horizontal mounting type. A conductive pattern 12 is formed on the surface mount substrate 11,
Electrical connection is made while fixing the semiconductor light emitting element 14 with the conductive paste 13. In the semiconductor light emitting device 14, electrodes 15 and 16 are formed on the front and back surfaces in a wafer state, and the electrodes 15 and 16 are joined to the conductive pattern 12 and the conductive paste 13. The PN junction surface 17 formed in parallel with the surface in the wafer state is mounted in a state perpendicular to the surface of the surface mount board 11. Semiconductor light emitting device 14
Is mounted by the surface mounting method, so that wire bonding is not necessary and the entire structure can be thinned.

According to Japanese Patent Publication No. 56-44591 mentioned above, in the vertical type semiconductor light emitting device 4 as shown in FIG. 7, since the fine line 7 is provided on the surface, as a measure for reducing the external efficiency of light emission,
A horizontal type similar to that of FIG. 8 is proposed. Furthermore, in Japanese Patent Laid-Open No. 54-22186 and Japanese Patent Laid-Open No. 6-177435,
There is disclosed a prior art in which a vertical type is changed to a horizontal type to eliminate wire bonds and improve productivity. The applicant of the present application discloses, in Japanese Unexamined Patent Publication No. 10-242533, a prior art in which an electrically insulating film is formed on at least the bottom surface of a horizontal LED chip to prevent the crystal plane of the semiconductor element from contacting other portions. .

[0007]

Compared to the vertical type as shown in FIG. 7, the horizontal type as shown in FIG. 8 adopts the surface mounting method, which eliminates the need for wire bonding and reduces the thickness. Can be planned. In the mounted state as shown in FIG. 8, the semiconductor light emitting element 14 emits light at the PN junction surface 17. The emitted light 18 emitted from the PN junction surface 17 is emitted from the chip top surface 19 to the outside. In order to keep the device height when the semiconductor light emitting device 14 is mounted low, at least the chip top surface 19 and the chip bottom surface 20 are used in dicing for wafer division.
It is necessary to set the dicing pitch, which determines the height between the and, as small as possible. Further, if one side of the semiconductor light emitting element 14 is shortened, in order to prevent the chip of the semiconductor light emitting element 14 from being peeled from the adhesive sheet fixing the wafer by the force received from the dicing blade during dicing,
The other side needs to have a certain length so that a sufficient area for the chip of the semiconductor light emitting element 14 to adhere to the adhesive sheet can be secured. That is, in order to reduce the thickness of the semiconductor light emitting device 14, the chip top surface 1
9 and one side of the chip bottom surface 20 which is perpendicular to the paper surface, it is necessary to secure a sufficient area for the chip of the semiconductor light emitting element 14 to adhere to the adhesive sheet.

Even after the length is adjusted in this way, the surface of the chip to be cut in the dicing step, which comes into contact with the dicing blade lastly, is fixed to the chip of the semiconductor light-emitting element 14 to cut the other surface. Since this is insufficient as compared with the case, this surface becomes rougher than other end surfaces due to vibration and the like. For this reason, the chip of the semiconductor light emitting element 14 having a minimum bonding area required to prevent the chip of the semiconductor light emitting element 4 from being peeled off from the adhesive sheet by the force received from the dicing blade during dicing is cut by the dicing device. In this case, only the last cut surface has a cut surface different from the other end surfaces.

The cut surface at the time of dicing has a large crystal damage, and electrical leakage and optical absorption increase as it is, and the damage is usually removed by etching or the like to flatten the surface. However, even if the damage and the like are sufficiently removed, the unevenness of the four cut surfaces does not become the same. If etching is attempted for a sufficiently long time, the electrodes that have already been formed or the film that protects the electrodes during etching will be damaged, or the anisotropy of the etching rate peculiar to the crystal orientation will become apparent. It becomes impossible to make two faces the same state.

An object of the present invention is to provide a method for manufacturing a semiconductor light emitting device, which can improve the light emission efficiency by utilizing the fact that the roughness of the surface to be cut last during dicing increases.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

SUMMARY OF THE INVENTION The present invention is a method for manufacturing a semiconductor light emitting device in which a plurality of semiconductor light emitting devices simultaneously formed on a wafer-shaped semiconductor material are cut and separated. It is a method for manufacturing a semiconductor light emitting device, characterized in that the cutting is performed last on the surface from which the light emission output is taken out.

According to the present invention, when the semiconductor light emitting element is cut and separated from the wafer-shaped semiconductor material, each semiconductor light emitting element is cut so that the surface from which the light emission output is taken is the last cut. Therefore, when the surface from which the light emission output is taken out is cut, the holding force of the suction sheet or the like becomes weak, and the roughness of the cut surface becomes large as compared with other cut surfaces. Since the light emission output is taken out from the cut surface having a large roughness, the light emission output can be taken out to the outside with a small attenuation inside the semiconductor light emitting element, and the light emission efficiency can be improved.

Further, in the present invention, the semiconductor light emitting element has a rectangular parallelepiped shape, and with respect to the wafer-shaped semiconductor material,
The cutting in the direction perpendicular to the surface from which the light emission output is taken out is performed first, and the cutting in the direction parallel to the surface from which the light emission output is taken out is taken out for each semiconductor light emitting element. It is characterized in that the surface opposite to the surface is cut first.

According to the present invention, when a plurality of semiconductor light emitting elements are cut and separated from a wafer-shaped semiconductor material, the light emission output is taken out by cutting in the direction parallel to the plane from which the light emission output is taken out. It is performed after cutting in the direction perpendicular to the surface, and for each semiconductor light emitting element, the cutting is performed so that the surface from which the light emission output is extracted becomes the last, so that semiconductor light emission in which the light emission efficiency is increased in order from the wafer-shaped semiconductor material. An element can be obtained.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a mounted state of an optical semiconductor element according to an embodiment of the present invention. In this embodiment, the conductive pattern 23 on the surface-mounting substrate 21 is applied to the conductive paste 23.
Then, the lateral semiconductor light emitting device 24 is mounted. The semiconductor light emitting element 24 is, for example, an LED, and a large number of semiconductor light emitting elements 24 are simultaneously formed on a wafer-shaped semiconductor material, and are mechanically cut and separated in a dicing process.

The semiconductor light emitting device 24 has electrodes 25 and 26 on the front and back sides in the wafer state, respectively. The PN junction surface 27 that emits light is parallel to the surface of the wafer, and is perpendicular to the surface of the surface mounting substrate 21 in the horizontal mounting state. The emitted light 28 is generated from the PN junction surface 27 and taken out from the chip top surface 29. The top surface 29 of the chip has a higher surface roughness than the bottom surface 30 of the chip and other side surfaces. In FIG. 1, the high roughness of the chip top surface 29 is exaggerated. Since the semiconductor light emitting device 24 is formed by using a crystal having a large refractive index of about 3.5, such as gallium phosphide (GaP) or gallium arsenide phosphide (GaAsP), the emitted light 28 is emitted from the semiconductor light emitting device 24. In order to come out of the chip, it is necessary to enter the crystal interface at a substantially right angle. For a refractive index of 3.5, an angle of incidence within about 17 ° is required. Since the top surface 29 of the chip is rough, even if the emitted light 28 is repeatedly totally reflected on the top surface 29 of the chip, the path from the total reflection to the total reflection should come out in a short state. You can For this reason, the probability that light can be emitted in a state where the degree of advancement inside the semiconductor light emitting element 24 is small becomes high, and therefore the chip luminous intensity can be improved.

As shown in FIG. 7, when the chip top surface 19 of the optical semiconductor element 14 is flattened, the emitted light 18 repeats total reflection inside the semiconductor light emitting element 14, and the semiconductor light emitting element 1
While being absorbed in the chip of No. 4, it is attenuated until it enters the chip surface of the semiconductor light emitting device 14 at an angle at which it can be emitted. In the present embodiment, as shown in an enlarged view in FIG. 2, the fine unevenness of the chip top surface 29 can be used to efficiently take out the emitted light 28 to the outside.

FIG. 3 shows an installation state when the semiconductor light emitting element 24 is assembled by the surface mounting method. The semiconductor light emitting element 24 is a bottom surface 30 of the chip, and the surface mounting substrate 21 shown in FIG.
To contact. The chip top surface 29, the chip bottom surface 30, and the side surfaces 31 and 32 at the time of assembly are cut surfaces from the wafer-shaped semiconductor material. The electrodes 25 and 26 are formed on both sides of the wafer surface. The wafer surface is extremely flat.

FIG. 4 shows a divided state when the semiconductor light emitting device 24 of the present embodiment is cut out from the semiconductor material wafer 40. The dicing line 41 which is cut first is cut corresponding to the side surfaces 31 and 32 of FIG. The dicing line 42 to be cut later cuts corresponding to the chip bottom surface 30 and the chip top surface 29 of FIG. Cutting order 43
For each semiconductor light emitting element 24, the chip bottom surface 30 side is cut first, and the chip top surface 29 side is cut last.

FIG. 5 shows an optical semiconductor device 2 according to this embodiment.
An outline of the manufacturing process of No. 4 will be shown. The manufacturing process starts from step s1, and in step s2, a plurality of semiconductor light emitting elements 24 are simultaneously formed on the wafer 40 by a wafer process.
Start the dicing process from step s3, and then step s
At 3, an adhesive sheet is attached to the back surface of the wafer 40. In step s4, the dicing line 41 for cutting shown in FIG. 4 is cut. Next, in step s5, the dicing line 42 to be cut later is cut. The order at this time is
The cutting order 43 of FIG. 4 is followed. In step s6, the respective semiconductor light emitting elements 24 are separated from the adhesive sheet and, for example, aligned and attached to a carrier tape or the like. Further, a performance test and the like are also performed, and the procedure ends in step s7.

FIG. 6 shows a state in which the dicing line 42 to be cut later in FIG. 4 is cut. The wafer 40 is attached to the adhesive sheet 44 and cut by the dicing blade 45. Regarding the dicing line 42 to be cut later, the semiconductor light emitting element 24a on the rear side of the cutting sequence 43
Is the last disconnect. Since the chip bottom surface 30 side has already been cut, the force received from the dicing blade 45 must be received only by the semiconductor light emitting element 24a. Therefore, the chip top surface 29 has a large roughness. On the other hand, for the semiconductor light emitting element 24b to be cut later in the cutting order 43, the dicing blade 45
Dicing line 42 for cutting after cutting
Cuts the bottom surface 30 of the chip. At this point, the chip top surface 29 is not separated from the chip bottom surface 30 of the semiconductor light emitting element that will be further cut, and the force from the dicing blade 45 can be received in a large area. The roughness of the bottom surface 30 of the chip can be made smaller than that of the top surface 29 of the semiconductor light emitting element 24a.

Although FIG. 6 describes full dicing in which all of the dicing lines are cut by the dicing blade 45, the entire dicing line is not cut, and scribing is performed in step s6 in FIG. Even in the case of bending and cutting, the roughness of the surface to be cut last is higher than that of the other cut surfaces, so that the present invention can be similarly applied. Further, the surface from which the emitted light is extracted is not the chip top surface 29 but the side surfaces 31 and 3.
Even if it becomes 2, etc., such side surfaces 31, 3
The present invention can be similarly applied if the cutting of 2 is performed last. Further, the present invention can be similarly applied even in the case of adopting a horizontal type for simply performing surface mounting without the purpose of thinning.

According to the present invention, the appearance and variations in optical characteristics due to the roughness of the cut surface, which have been a problem in the past, can be eliminated, and the luminous efficiency can be improved by improving the extraction efficiency.

[0030]

[0031]

[0032]

[0033]

According to the present invention, when the individual semiconductor light emitting elements are separated from the wafer-shaped semiconductor material, the cutting order is such that the surface from which the light emission output is taken out is the last. It is possible to manufacture a good semiconductor light emitting device.

Further, according to the present invention, it is possible to efficiently manufacture a plurality of semiconductor light emitting devices from a wafer-shaped semiconductor material in a state where the luminous efficiency is good.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view showing a mounted state of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a reflection state of emitted light 28 at a chip top surface 29 portion of FIG.

3 is a perspective view showing an assembled state of the semiconductor light emitting device 24 of the embodiment of FIG. 1. FIG.

4 is a simplified plan view showing dicing lines 41 and 42 for separating the semiconductor light emitting device 24 of FIG. 1 from a wafer 40. FIG.

5 is a flowchart showing a process of manufacturing the semiconductor light emitting device 24 of the embodiment of FIG. 1. FIG.

FIG. 6 is a partial cross-sectional view showing a state in which a dicing line 42 for cutting after FIG. 2 is cut.

FIG. 7 is a simplified cross-sectional view showing a mounted state of a conventional vertical semiconductor light emitting device.

FIG. 8 is a simplified cross-sectional view showing a mounting state of a conventional horizontal semiconductor light emitting device.

[Explanation of symbols]

21 Surface mount board 22 Conductive pattern 23 Conductive paste 24, 24a, 24b Semiconductor light emitting device 25,26 electrodes 27 PN junction surface 28 emitted light 29 chip top surface 30 chip bottom 40 wafers 41 Dicing line for cutting first 42 Dicing line for cutting after 43 cutting order 44 Adhesive sheet 45 dicing blade

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 33/00

Claims (2)

(57) [Claims] 1. A method of manufacturing a semiconductor light-emitting device, comprising cutting a plurality of semiconductor light-emitting devices simultaneously formed on a wafer-shaped semiconductor material to separate the semiconductor light-emitting devices from each other. A method for manufacturing a semiconductor light emitting device, characterized in that cutting is performed last. 2. The semiconductor light emitting element has a rectangular parallelepiped shape, and the wafer-shaped semiconductor material is first cut in a direction perpendicular to a surface from which the light emission output is taken out, and the light emission output is 3. The cutting in the direction parallel to the extraction surface is performed so that, for each semiconductor light emitting element, the surface opposite to the surface from which the emission output is extracted is cut first. Manufacturing method of semiconductor light emitting device of.