JP4166887B2 - Optical semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical semiconductor device, and more particularly to an optical semiconductor device having a lens.
[0002]
[Prior art]
A conventional optical semiconductor device is disclosed in, for example, Japanese Patent Publication No. 7-16017. The optical semiconductor device described in this publication has an optical semiconductor chip electrically connected to a lead portion, and the optical semiconductor chip and a part of the lead portion are sealed with a light-transmitting mold resin such as epoxy resin. The optical semiconductor element is configured to be stopped, and a hemispherical lens portion is integrally provided on the optical semiconductor element. Such an optical semiconductor device is molded by, for example, a transfer molding method or the like, and molds such as a lead portion, a lens portion, and an optical semiconductor element are used as molds used in this molding method. In addition, a light shielding case having a condenser lens is attached to the optical semiconductor device with the lens portion, and an air layer exists between the lens portion and the condenser lens. On the other hand, the optical semiconductor element can also be formed by a casting method.
[0003]
[Problems to be solved by the invention]
However, in the conventional optical semiconductor device described above, since the lens portion and the optical semiconductor element are integrally formed by a transfer molding method, the positional accuracy of the optical semiconductor chip with respect to the lens portion is improved, but the mold shape is complicated. Therefore, the mold is required to have extremely high accuracy, becomes very expensive, and it becomes difficult to manufacture an optical semiconductor device that does not require mass production. On the other hand, in the case of molding by the casting method, it is possible to manufacture at a low cost, but there is a problem in the position accuracy with respect to the lens portion.
[0004]
Further, in the optical semiconductor device, the lens portion and the optical semiconductor element are integrally formed of an epoxy resin because of the necessity of increasing the positional accuracy of the optical semiconductor chip with respect to the lens portion. However, in the optical semiconductor device, an epoxy resin is used as the lens portion. A material having higher transparency is required, and improvement of its optical characteristics is required.
[0005]
Further, since an air layer exists between the lens unit and the condenser lens, when light enters the condenser lens, the boundary surface between the air layer and the lens unit, and the air layer and the condenser lens There is a possibility that reflection loss occurs at the boundary surface of the optical semiconductor device and the optical characteristics of the optical semiconductor device as a whole deteriorate.
[0006]
The present invention has been made in view of the above-described problems, and provides an optical semiconductor device that can be manufactured at low cost while maintaining good positional accuracy of an optical semiconductor chip and that has improved optical characteristics. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention is configured by sealing an optical semiconductor chip with a light-transmitting mold resin and having a flat joint surface on the light receiving surface or light projecting surface side of the optical semiconductor chip. A lens body including a semiconductor element and an alignment portion corresponding to the shape of the optical semiconductor element including a flat bottom surface facing the bonding surface of the optical semiconductor element, and formed from a light-transmitting lens molding resin different from the molding resin And a translucent adhesive that is interposed between the bottom surface and the bonding surface of the alignment portion in a state where the optical semiconductor chip is aligned on the optical axis of the lens body, and bonds the optical semiconductor element and the lens body; The chamfered portion is formed at the corner portion of the joint surface, and the region surrounded by the alignment portion and the chamfered portion is widened toward the bottom surface side .
[0008]
According to this optical semiconductor device, the optical semiconductor element is made of mold resin, the lens body is made of lens molding resin, and the mold resin and lens molding resin are made different from each other. It becomes possible to select a suitable resin. Further, when the optical semiconductor device is assembled, the optical semiconductor element is easily aligned with the lens body by bonding the bonding surface and the bottom surface of the alignment portion of the lens body. In use, since the lens body and the adhesive material are both translucent when light enters the light receiving surface or the light projecting surface of the optical semiconductor chip from the outside, the interface between the lens body and the adhesive material The reflection of incident light can be suppressed. Moreover, since this chamfered portion is formed at the corner portion of the joint surface, when joining the lens body and the optical semiconductor element via the adhesive, the liquid adhesive is dropped onto the alignment portion, When this liquid adhesive is pressed against the joint surface of the optical semiconductor element, air in the adhesive can be released.
[0009]
The mold resin preferably contains an epoxy resin, and the lens molding resin preferably contains an acrylic resin, and more preferably contains polymethyl methacrylate as the acrylic resin. In this case, since the transparency of the acrylic resin is higher than that of the epoxy resin, the optical characteristics of the lens body are improved. In particular, when the acrylic resin is polymethyl methacrylate, the optical properties of the lens body are further improved due to the high transparency of polymethyl methacrylate.
[0010]
Moreover, it is preferable that mold resin consists of resin which selectively permeate | transmits the light of a specific wavelength range. According to this optical semiconductor device, when light is incident on the optical semiconductor element through the lens body, light in a specific wavelength region is selectively transmitted and incident on the optical semiconductor chip.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of an optical semiconductor device according to the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is an exploded perspective view of an optical semiconductor device. As shown in the figure, the optical semiconductor device 1 includes a thick flat plate-shaped optical semiconductor element 6. This optical semiconductor element 6 has two lead portions 2 and 3, and one lead portion 2 is provided with a flat tip portion 2 a, and a flat plate-like optical semiconductor is provided on the tip portion 2 a. A chip 4 (for example, a light receiving element) is fixed. The optical semiconductor chip 4 is connected to the other lead portion 3 through an Au thin wire 5. The optical semiconductor chip 4 and part of the lead portions 2 and 3 are sealed with a translucent mold resin (for example, epoxy resin) by a transfer molding method or the like. In addition, a flat rectangular bonding surface 6a is formed in the mold resin at a position facing the light receiving surface 4a of the optical semiconductor chip 4, and the bonding surface 6a and the light receiving surface 4a of the optical semiconductor chip 4 are parallel to each other. It has become. And the junction part 6b is provided along the four sides of this junction surface 6a. Here, the optical semiconductor element 6 is made with an accuracy that is within ± 0.03 even if the outer dimensions thereof include variations.
[0013]
On the other hand, the optical semiconductor device 1 has a bullet-shaped lens body 10 made of a lens molding resin different from that of the optical semiconductor element 6. The lens body 10 is integrally provided with an alignment frame portion 8 as an alignment portion, and the alignment frame portion 8 has a shape corresponding to the optical semiconductor element 6. That is, the alignment frame portion 8 includes a rectangular flat plate-like flat portion 16 and a guide portion 17 along three sides of the flat portion 16, and the bottom surface 16 a of the flat portion 16 is bonded to the optical semiconductor element 6. It is joined to the surface 6 a, and the joint portion 6 b of the optical semiconductor element 6 is joined to the guide portion 17. The lens body 10 is provided on the flat portion 16.
[0014]
As the lens molding resin constituting the lens body 10, acrylic resin is used because it is more transparent than epoxy resin. Here, it is preferable to use polymethyl methacrylate (PMMA) as the acrylic resin. The reason why polymethyl methacrylate is used is that polymethyl methacrylate has a very high transparency and is suitable as the lens body 10. Further, polymethyl methacrylate itself is inexpensive and has good moldability. In the case where the lens body 10 is molded with such an acrylic resin, the lens body 10 is molded by, for example, an automatic mass molding method such as an injection molding method. Therefore, the lens body 10 is molded with almost the same accuracy as the optical semiconductor element 6. Further, when the lens body 10 is required to have heat resistance, polycarbonate (PC) can be used as the acrylic resin.
[0015]
FIG. 2 is a front view showing the optical semiconductor device 1. As shown in the figure, the lens body 10 and the optical semiconductor element 6 are joined with a translucent adhesive 9 interposed between the alignment frame portion 8 and the joining surface 6a of the optical semiconductor element 6, In this bonded state, the optical semiconductor chip 4 is arranged in a state of being aligned on the optical axis C of the lens body 10. Here, for example, a thermosetting resin is used as the adhesive 9, and it is particularly preferable to use an epoxy resin, a silicone resin, an acrylic resin, or the like. This is because these thermosetting resins have values close to the refractive indexes of the mold resin and the lens molding resin.
[0016]
A chamfered portion 11 for venting air is formed at the corner portion of the joint surface 6 a of the optical semiconductor element 6. When the lens body 10 and the optical semiconductor element 6 are bonded via the adhesive 9, the chamfered portion 11 drops the liquid adhesive 9 onto the alignment frame 8, and this liquid adhesive This is to allow air in the adhesive 9 to escape when 9 is pressed by the joining surface 6a of the optical semiconductor element 6.
[0017]
Thus, according to the optical semiconductor device 1 described above, since the lens body 10 is made of an acrylic resin different from the epoxy resin of the optical semiconductor element 6, it is possible to improve the optical characteristics of the lens body 10. It becomes. In particular, when polymethyl methacrylate is used as the acrylic resin constituting the lens body 10, the optical properties of the lens body 10 are further improved because the polymethyl methacrylate has a particularly high transparency. In addition, when light enters the light receiving surface 4a of the optical semiconductor chip 4 through the lens body 10, the refractive index of the adhesive 9 has a value close to the refractive index of the lens molding resin and the molding resin. And the adhesive 9 and the interface between the adhesive 9 and the optical semiconductor element 6 can suppress the reflection of incident light.
[0018]
In addition, since the lens body 10 and the optical semiconductor element 6 are formed of different resins when the optical semiconductor device 1 is manufactured, the lead portions 2 and 3 and the optical semiconductor element 6 and the like are formed when the lens body 10 is molded. It is no longer necessary to form the mold in a mold used for molding, and the shape of the mold does not become complicated. On the other hand, since the lens body 10 is molded by an automatic mass molding method of an injection molding method using an acrylic resin, a mold used for molding can be made smaller than in the transfer molding method. For this reason, it is possible to reduce the price of the mold itself, and consequently, the price of the optical semiconductor element 6 can be reduced. Specifically, the price of the mold can be reduced to about 1/10 of the conventional product. Therefore, it is possible to cope with the production of small quantities and many varieties that do not require mass production. Further, when the lens body 10 is molded, the shape of the mold used for molding the lens body 10 does not become complicated, so that bubbles are less likely to accumulate in the lens body 10 and molding defects are less likely to occur than in the case of the transfer molding method. This improves the product yield.
[0019]
Further, when the optical semiconductor device 1 is assembled, the optical semiconductor element 6 is reliably aligned with the lens body 10 by bonding the bonding surface 6 a to the bottom surface 16 a of the alignment frame portion 8 of the lens body 10. Is done. At this time, since the optical semiconductor element 6 and the alignment frame portion 8 of the lens body 10 are made with the same high dimensional accuracy, the positional deviation of the optical semiconductor chip 4 with respect to the lens body 10 becomes extremely small, and the lens The lens effect of the body 10 can be sufficiently exhibited.
[0020]
Since the lens body 10 and the optical semiconductor element 6 are made of different resins, it is of course possible to use a commercially available product only for the optical semiconductor element 6 and manufacture the lens body 10 according to this shape. .
[0021]
Next, a second embodiment of the optical semiconductor device according to the present invention will be described. In the figure, the same reference numerals are assigned to the same or equivalent components as those in the first embodiment.
[0022]
As shown in FIG. 3, in the optical semiconductor device 20, the lens body 10 is larger than the optical semiconductor element 6, and an alignment recess serving as an alignment portion is provided in a cylindrical base portion 12 provided in the lens body 10. 13 is different from the optical semiconductor device 1 of the first embodiment in that 13 is formed. The alignment recess 13 is formed to a depth at which the optical semiconductor element 6 is buried by reaching the lens body 10 from the lower surface side of the base portion 12. The shape of the recess 13 is a shape corresponding to the upper shape of the optical semiconductor element 6, that is, a shape in which the upper part of the optical semiconductor element 6 can be filled. And the bottom face 13a of this recessed part 13 is a flat surface, and is mirror-finished. The base portion 12 is formed with guide grooves 14 and 15 extending from the recess 13 to the outer peripheral surface 12 a of the base portion 12, and the guide grooves 14 and 15 project the two grooves protruding from the mold resin of the optical semiconductor element 6. Lead portions 2 and 3 (see FIG. 5) are guided.
[0023]
According to this optical semiconductor device 20, the optical semiconductor element 6 is buried in the recess 13, so that the alignment becomes easier than when the optical semiconductor element 1 is assembled. Further, since the bottom surface 13a of the recess 13 is mirror-finished, reflection when light enters the bottom surface 13a is suppressed. In this type of optical semiconductor device 20, the lens body 10 is larger than the optical semiconductor element 6, and its manufacture is difficult by the conventional transfer molding method. This type of optical semiconductor device 20 can also be manufactured.
[0024]
In addition, this invention is not limited to embodiment mentioned above. For example, in addition to the optical semiconductor devices 1 and 20 of the above-described embodiments, various types of optical semiconductor devices can be manufactured. For example, an optical semiconductor device 30 as shown in FIGS. 6 and 7 can be manufactured. That is, the lens body 10 of the optical semiconductor device 30 has a bell-shaped outer shape, and the alignment recess 13 as the alignment portion is directly formed in the lens body 10. This is different from the optical semiconductor device 20 according to the second embodiment in which the alignment recess 13 is formed in the base portion 12 of the lens body 10. The recess 13 has a shape that matches the outer dimension of the upper portion of the optical semiconductor element 6.
[0025]
Further, as another example of the lens body 10, a shape as shown in FIGS. That is, the lens body 10 has a cylindrical portion 10b and a truncated cone portion 10c, and a truncated conical recess 10d is formed in the truncated cone portion 10c. On the other hand, an alignment recess 13 as an alignment portion is formed on the flat surface portion 10a of the cylindrical portion 10b.
[0026]
The lens body 10 is not limited to the shape shown in FIGS. 1 to 6, and may have any shape as long as the shape is suitable as a lens body.
[0027]
It is also possible to configure only the mold resin with a resin that selectively allows light in a specific wavelength range to pass therethrough so that the mold resin has a filter effect. For example, when the mold resin is black, when the light from outside enters the light receiving surface 4a of the optical semiconductor chip 4 through the lens body 10, only the light in the visible region and the ultraviolet region is cut by the mold resin. Only the light in the infrared region is selectively guided to the light receiving surface 4 a of the optical semiconductor chip 4. The resin that selects light in a specific wavelength range is appropriately selected according to the wavelength to be selected.
[0028]
Furthermore, in the above-described embodiment, the light receiving element is used as the optical semiconductor chip 4, but a light emitting element may be used. In this case, the lens body 10 has a function of diverging light emitted from the light projecting surface of the optical semiconductor chip 4.
[0029]
【The invention's effect】
As described above, the optical semiconductor device according to the present invention is configured by sealing an optical semiconductor chip with a light-transmitting mold resin, and has a flat joint surface on the light receiving surface or light projecting surface side of the optical semiconductor chip. A lens body including a semiconductor element and an alignment portion corresponding to the shape of the optical semiconductor element including a flat bottom surface facing the bonding surface of the optical semiconductor element, and formed from a light-transmitting lens molding resin different from the molding resin And the optical semiconductor element and the lens body are joined by interposing between the bottom surface of the alignment portion and the joint surface in a state where the optical semiconductor chip is aligned on the optical axis of the lens body. The optical semiconductor chip can be manufactured at low cost while maintaining the positional accuracy of the optical semiconductor chip with respect to the lens body, and the optical characteristics can be improved.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a first embodiment of an optical semiconductor device of the present invention.
2 is a front view showing the optical semiconductor device of FIG. 1. FIG.
FIG. 3 is a front view showing a second embodiment of the optical semiconductor device of the present invention.
4 is a plan view of the optical semiconductor device of FIG. 3. FIG.
5 is a plan view of the optical semiconductor element of FIG. 3. FIG.
FIG. 6 is a perspective view showing a third embodiment of the optical semiconductor device of the invention.
7 is a longitudinal front view of the optical semiconductor device of FIG. 6. FIG.
FIG. 8 is a perspective view showing a fourth embodiment of the optical semiconductor device of the present invention.
9 is a longitudinal front view of the optical semiconductor device of FIG. 8. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,20,30 ... Optical semiconductor device, 4 ... Optical semiconductor chip, 4a ... Light-receiving surface, 6 ... Optical semiconductor element, 6a ... Joining surface, 8 ... Positioning frame part (positioning part), 9 ... Adhesive material, 10 ... Lens body, 13 ... Positioning recess (positioning part).

Claims (4)

An optical semiconductor element that is configured by sealing an optical semiconductor chip with a translucent mold resin, and has a flat bonding surface on the light receiving surface or the light projecting surface side of the optical semiconductor chip;
A lens body including a flat bottom surface facing the bonding surface of the optical semiconductor element and having an alignment portion corresponding to the shape of the optical semiconductor element, and formed from a light-transmitting lens molding resin different from the molding resin When,
Translucent light that is interposed between the bottom surface of the alignment portion and the bonding surface in a state in which the optical semiconductor chip is aligned on the optical axis of the lens body, and bonds the optical semiconductor element and the lens body. Adhesive material, and
A chamfered portion is formed at the corner of the joint surface ,
The joining structure characterized by the area | region enclosed by the said alignment part and the said chamfering part spreading toward the said bottom face side . The joining structure according to claim 1, wherein the mold resin includes an epoxy resin, and the lens molding resin includes an acrylic resin. The joining structure according to claim 2, wherein the acrylic resin contains polymethyl methacrylate. The joining structure according to claim 1, wherein the mold resin is made of a resin that selectively transmits light in a specific wavelength region.

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