JP3148482B2 - Method for manufacturing light emitting element used for optical coupling element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a light emitting element used in the optical coupling element which light emission element is covered with the precoat resin.

[0002]

2. Description of the Related Art The structure of a conventional optical coupling device will be described with reference to FIG. 6 or FIG. FIG. 6 is a side sectional view showing a conventional example. FIG. 7 is a diagram showing another conventional example.
(A) is a side sectional view, and (b) is an enlarged plan view of a light emitting unit.

FIG. 6 shows an optical coupling element called a double transfer mold type, which is a light emitting element (LED).
The chip 1 and the light receiving element chip 2 are bonded and fixed (die-bonded) on a pair of lead frames 3, 3 'made of 42alloy, Cu, or the like with an Ag paste (not shown) or the like, and the gold wires 4, 4', etc. The light emitting / receiving element chips 1 and 2 are electrically connected (wire-bonded) to the lead frames 3 and 3 'using a transparent resin (precoat resin) 5 such as silicone for protecting the chip. After arranging the light receiving and emitting element chips 1 and 2 at opposing positions, the light emitting element chip 1 and the light receiving element chip 2 are molded with a translucent resin 6 mainly made of epoxy resin or the like, and It is molded with a light-shielding resin 7 mainly made of an epoxy resin or the like.

FIG. 7 shows an optical coupling element called an AC input type, and only different points from the optical coupling element shown in FIG. 6 will be described.

In the conventional optical coupling device, as shown in FIG. 7B, two light emitting device chips 1, 1 are die-bonded to respective light emitting side lead frames 3, 3 with an Ag paste or the like. Each of the light emitting element chips 1, 1 is covered with a precoat resin 5 by wire bonding to different poles by gold wires 4, 4 ', respectively.

[0006]

FIG. 8 is an enlarged view showing a light emitting portion of the optical coupling element shown in FIG. 6, (a) is a plan view, and (b) is BB of (a). FIG.

As shown in the figure, the header of the lead frame 3 is provided with a recess 8 previously formed by punching with a die, and the light emitting element chip 1 is die-bonded to the recess 8. This is to make the height from the upper surface of the frame to the upper surface of the chip as low as possible when the light emitting element chip 1 is precoated with the precoat resin. For example, as shown in FIG. 8B, if the length of the base L is constant,
This is because the light emitting element chip 1 can be more reliably covered with the precoat resin 5 when the chip height H is lower, and the light emitting element chip 1 can be protected from residual stress such as a mold. Here, if the header is planar,
It was very difficult to reliably cover with the precoat resin 5. This is because the corner of the upper end of the light emitting element chip 1 is exposed to exceed the surface tension of the resin.

However, as described above, when the recess 8 formed by punching with a die is provided in the header of the lead frame 3, as shown in FIG. A), the flatness of the swelling header is lost, and as a result, in the die bonding or wire bonding process, there are problems such as a tilt of the light emitting element chip 1, a deviation in position accuracy, a variation in wire bonding accuracy, and a variation in bonding strength.

In addition, the AC input type optical coupling device shown in FIG. 7 requires two headers as shown in FIG. 7B, so that two headers are added to one header portion of the above-mentioned conventional example. And one header size had to be very small. Therefore, unlike the above-described conventional example, a recess cannot be provided in the header. Therefore, as shown in FIG. 9A, the header is die-bonded, wire-bonded, and pre-coated without the recess.

However, when the viscosity of the pre-coat resin 5 decreases due to the variation in the amount of the pre-coat resin 5 applied during pre-coating or the temperature during curing, the corner of the upper end of the light emitting element chip 1 has a surface tension of the pre-coat resin 5. There was a problem that the exposure exceeded the limit. When the precoat resin 5 is applied in a large amount, as shown in FIG. 9B, the precoat resin 5 wraps around the back surface of the header when the viscosity decreases, and the translucent resin 6 after resin molding with the translucent resin 6 is used. There was a problem that the precoat resin 5 was more exposed.

As a method of solving this problem, there has been a method of adjusting the additives and the like of the precoat resin 5 to adjust the viscosity and the flowability, but it is difficult to adjust the viscosity and the flowability in a narrow range. There was a problem in consideration of the manufacturing variation of the resin 5 and the like.

[0012] The present invention has been made in view of the above problems, it is possible to prevent the exposure of the corners of the top surface edge of the light emitting device chip, the manufacturing method of the light emitting element used in the optical coupling element which can be reduced in the coating amount of the precoat resin It is intended to be provided.

[0013]

This onset bright [Means for solving problems], die-bonded to the light emitting element and a light receiving element are each separate lead frame,
Wire bonded, the light emitting element is covered with precoat resin, the light emitting element and the light receiving element is arranged to optically couple, Ri Na sealed with resin, the upper surface of the light emitting element
This is a method for manufacturing a light emitting element used for an optical coupling element formed in a pyramid shape having a stepped step, in which dicing is performed by sequentially increasing the width and decreasing the depth with dicing blades having different widths. Later, the light-emitting element is divided into individual light-emitting elements, thereby manufacturing a light-emitting element having an upper surface formed in a pyramid shape with a step-like step.

[0014]

[Action] of the configuration optocoupler has a constitution in which the upper surface of the light emitting element is formed in a pyramid shape of the graded step without surface tension of the precoat resin is impaired, the more reliably the light emitting element It is possible to prevent the corner of the upper surface end of the light emitting element from being exposed exceeding the surface tension of the precoat resin as in the related art. Therefore, failure of the light emitting element due to residual stress of a mold or the like can be prevented.

Further, since the light emitting element can be precoated with a smaller amount of resin, there is an advantage in cost. According to the method for manufacturing a light emitting device of the present invention, a light emitting device used for such an optical coupling device can be easily manufactured.

[0016]

FIG. 1 is an enlarged sectional view of a main part showing a reference example. In the present reference example, only differences from the conventional example shown in FIG. 6 or 7 will be described.

[0017] As FIG. 1, the optical coupling device of the present embodiment is for the upper surface of the light-emitting element chip 1 mounted on the lead frame 3 is formed in a hemispherical shape, the light emitting element chip 1 precoating It is covered with the precoat resin 5 using the surface tension of the resin 5.

Hereinafter, an example of a method of manufacturing the light emitting element chip 1 will be described with reference to FIG.

First, as shown in FIG. 2A, P-type and N-type layers are sequentially formed on a GaAs substrate to form a P-type layer forming a light emitting portion.
An N junction is formed. Next, about 5 mm from the surface of the GaAs substrate
So-called half dicing is performed to a depth leaving 0 to 200 microns. Thereafter, a resist 11 is selectively applied to a portion to be a bonding pad, and all other portions are exposed. Next, etching is performed after application of the resist 11, and as shown in FIG. 2B, it is necessary to control the etching time so that the etching is performed. Here, if the etching time is too long, FIG.
Care must be taken because the overetching is performed as shown in (1). This is over-etched,
This is because corners are formed on the upper surface of the light emitting element chip. After that, it is divided individually at the dicing line and
The light emitting element chip 1 shown in FIG.

FIG. 3 is an enlarged sectional view of a main part showing an embodiment of the present invention . In the present embodiment, only the points different from the above-mentioned reference example will be described.

As shown in FIG. 3, the optical coupling device according to the present embodiment has a stepped step so that the upper surface of the light emitting element chip 1 has a pyramid shape.

Hereinafter, an example of a method for manufacturing the light emitting element chip 1 will be described with reference to FIG.

First, in the same manner as described above, P-type and N-type layers are sequentially formed on a GaAs substrate to form a PN junction forming a light emitting portion, and when dicing is performed from the surface side, as shown in FIG. As described above, while the width of the dicing blade 12 is gradually increased, the dicing depth is gradually reduced,
A stepped step is provided on the surface, and then the light emitting element chip 1 as shown in FIG.

In the above manufacturing process, the width of the dicing blade 12 is desirably increased by several μm, and the dicing depth is desirably decreased by μm. This is because if each of them exceeds 10 μm, the angle of each step may exceed the surface tension of the resin and may be exposed.

In this embodiment, the corners of the steps are removed by etching or the like, so that pre-coating can be performed more effectively.

The optical coupling element of the present invention is not limited to the above embodiment, and for example, the upper surface of the light emitting element chip may have a polygonal shape not exceeding the surface tension of the precoat resin.

As described above, since the upper surface of the light emitting element chip 1 is formed in a pyramid shape having a step , the optical coupling element of the present invention can be used without impairing the surface tension of the precoat resin 5. As a result, the light emitting element can be more reliably covered, and the corner of the upper end of the light emitting element can be prevented from being exposed beyond the surface tension of the precoat resin as in the related art. Therefore, failure of the light emitting element chip 1 due to residual stress of a mold or the like can be prevented.

Further, since the light emitting element chip 1 can be precoated with a smaller amount of resin, there is a merit in cost.

Further, in the double transfer mold type optical coupling element, since the precoating with the precoating resin 5 can be performed stably, there is no need to provide a recess in the header of the lead frame, and the parallelism of the back surface of the header is stabilized. , Die bonding, wire bonding, and the like can be performed stably, and a high quality optical coupling device with good productivity can be obtained.

Further, in the AC coupling type optical coupling device, as shown in FIG. 5, for example, as shown in FIG. The pre-coated resin is not exposed from the translucent resin after the resin molding according to (1), and stable resin molding can be performed. Therefore, a high-quality optical coupling device with good productivity can be obtained.

[0031]

As described above, according to the production method of the present invention ,
According to the optical coupling element using the manufactured light emitting element, since the upper surface of the light emitting element is formed in a pyramid shape having a stepped step, the light is more reliably emitted without impairing the surface tension of the precoat resin. The element can be covered. Therefore, failure of the light emitting element due to residual stress of a mold or the like can be prevented.

Further, since the light emitting element can be pre-coated with a smaller amount of resin, the cost is reduced.

Thus, a high-quality optical coupling device with good productivity can be obtained. According to the method for manufacturing a light emitting device of the present invention,
A light emitting element used for such an optical coupling element can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing a reference example.

FIG. 2 is a diagram for explaining an example of a method for manufacturing the light emitting device shown in FIG.

FIG. 3 is an enlarged sectional view of a main part showing one embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of a method for manufacturing the light emitting device shown in FIG.

FIG. 5 is an enlarged sectional view of a main part showing an AC input type optical coupling element according to the present invention.

FIG. 6 is a side sectional view showing a conventional example.

7A and 7B are diagrams showing another conventional example, in which FIG. 7A is a side sectional view, and FIG. 7B is an enlarged plan view of a light emitting portion.

8 is an enlarged view showing a light emitting portion of the optical coupling element shown in FIG. 6, (a) is a plan view, and (b) is BB of (a).
FIG.

9 is a cross-sectional view for explaining a pre-coated state of the optical coupling device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light receiving element 3, 3 'Lead frame 4, 4' Gold wire 5 Precoat resin 6 Translucent resin 7 Light shielding resin

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-232378 (JP, A) JP-A-4-356976 (JP, A) JP-A-55-48984 (JP, A) JP-A-50- 81477 (JP, A) JP-A-62-139365 (JP, A) JP-A-64-5079 (JP, A) JP-A-60-113654 (JP, U) JP-A-4-23152 (JP, U) Japanese Utility Model Application Sho 61-4307 (JP, U) Japanese Utility Model Application Hei 4-59166 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 31/12 H01L 33/00

Claims (1)

(57) [Claims] 1. A light-emitting element and a light-receiving element are die-bonded and wire-bonded to respective lead frames, the light-emitting element is covered with a precoat resin, and the light-emitting element and the light-receiving element are arranged so as to be optically coupled. , Ri Na <br/> resin encapsulation, the upper surface of the light emitting element of the phased step pyramid
Light- emitting element used for optical coupling element formed in shape
Manufacturing method, when the width is sequentially increased with dicing blades having different widths,
After dicing with shallow depth, light emitting element
Is divided into individual parts, so that the upper surface
Manufacture of a light emitting element formed in a lamid shape
A method for manufacturing a light-emitting element, comprising: