JP5032747B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device.

  Today, light emitting elements with high luminance and high output and small and favorable semiconductor devices have been developed and used in various fields. Such a semiconductor device is used for, for example, an optical printer head light source, a liquid crystal backlight light source, various meter light sources, various reading sensors, and the like by taking advantage of features such as small size, low power consumption, and light weight.

A semiconductor device (hereinafter also referred to as an LED) is small, efficient, and capable of emitting bright colors. In addition, since it is a light emitting element, it has the characteristics that it has no ball breakage, excellent initial drive characteristics and earthquake resistance, and is strong against repeated ON / OFF lighting. The liquid crystal backlight light source for mobile phones and the liquid crystal backlight light source for PDA are becoming thinner, and problems associated with the reduction in thickness are occurring.

JP 2003-57622 A

Since the package member is made of resin and the lead electrode is made of metal, adhesion and adhesion are poor. Therefore, there may be a gap at the interface formed by the package member and the lead electrode . As a result, the mold member leaks from the gap. If the distance of the 2nd site | part covered with a package member is short, the probability that the mold member will leak to the 3rd site | part projected from the outer wall surface of a package member will become high. The leaked mold member causes various problems such as generation of burrs at the time of cutting and forming and adhesion to a third portion protruding from the outer wall surface of the package member, such as poor solder mountability.

Among the semiconductor devices, the type in which the light emitting surface is perpendicular to the mounting surface (hereinafter also referred to as a side view type) is required to be thin, and the distance of the second part covered by the package member tends to be short. Problems are likely to occur. In particular, in the case of a type having a plurality of light emitting elements, the number of lead electrodes also increases, so the degree of freedom for increasing the distance of the second part covered by the package member is reduced.

  Further, when the mold member contains a fluorescent material that converts the wavelength of light from the light emitting element, the fluorescent material also leaks together with the mold member, resulting in a shift from the target chromaticity.

Therefore, an object of the present invention is to provide a semiconductor device that can prevent a mold member from leaking from a package member .

In order to achieve the above object, a semiconductor device according to claim 1 of the present invention includes a light emitting element and a recess in which the light emitting element is disposed, and an outer lead electrode electrically connected to the light emitting element. In a semiconductor device having a package member made of an inserted resin and a mold resin covering the light emitting element in the recess, the outer lead electrode is partially exposed in the extension in the extending direction. A second portion of the outer lead electrode, and a second portion covered by the package member, and a third portion protruding from the outer wall surface of the package member. It may have a groove portion serving as a barrier mold member leaking from the interface between the package member and the outer lead electrodes to the outer wall surface direction of the package member, wherein the mold member is stored in the groove It is characterized by comprising. This configuration, the mold member leaking from the package member and the outer lead electrode interface is prevented from leaking to the thus damming is outside of the package to at least one or more grooves perpendicular to the extending direction of the outer lead electrodes Is possible.

  A groove part means a streak-like recessed part. Further, the protruding portion refers to a line-like convex portion.

In addition, the semiconductor device of the present invention is preferably a type in which the light emitting surface is perpendicular to the mounting surface, that is, a side view type. Semiconductor devices can be broadly divided into a top view type and a side view type. However, comparing the two, the side view type was originally developed for thinning, and there is a demand for further thinning. Great effect. That is, as the thickness is reduced, the wall forming the recess of the package member becomes thinner and the second part of the lead electrode, which is the leakage path of the mold member, becomes shorter. This is due to the prominent leakage problem.

  Further, in the case where the emission color is white light, in principle, the configuration of only one light emitting element is not sufficient to make the emission color white, and an additional configuration is required. The more complicated the configuration, the closer the problem and the greater the effect of the present invention.

  Furthermore, the mold member contains a fluorescent material that converts the wavelength of light from the light emitting element. In order to obtain an arbitrary emission color, the amount of the fluorescent material is adjusted and contained, but when the mold member leaks, the fluorescent material also leaks together with the mold member. By using the invention, it is possible to prevent chromaticity deviation.

Furthermore, in the semiconductor device of the present invention , the mold member is preferably a silicone resin or an epoxy resin .

Furthermore, in the semiconductor device according to a fourth aspect of the present invention, in addition to the feature according to any one of the first to third aspects, the outer lead electrodes have different widths, and the groove portion is formed only in the larger width. having. In some cases, the width of the outer lead electrode is varied from the viewpoint of heat dissipation and mountability of the light emitting element. Naturally, as the width of the outer lead electrode is increased, the gap formed at the interface between the package member and the outer lead electrode is increased, and the mold member is likely to leak. Therefore, by providing the groove only on the wide outer lead electrode, it is possible to prevent leakage of the mold member.

Further, the method for forming a semiconductor device of the present invention includes a light emitting element, a package member having a recess in which the light emitting element is mounted, and a lead electrode electrically connected to the light emitting element, and the recess. In a method for forming a semiconductor device having a mold member for covering the light emitting element therein, a first step of forming a groove or a protrusion on a part of a lead frame for punching a metal flat plate, and a resin material A second step of forming a package member having a recess in the lead frame so as to cover at least the groove or protrusion, and a light emitting element is disposed in the recess, and the light emitting element and the lead The method includes a third step of electrically connecting the frame and a fourth step of injecting a mold material into the recess and curing it to form a mold member.

The semiconductor device of the present invention is preferably a plurality of light emitting elements having different emission colors. Since light emitting elements having different emission colors necessarily have different operating voltages, an extra lead electrode is required as compared with the case of one chip. If it becomes so, the structure which lengthens the distance of the 2nd site | part coat | covered with a package member will become difficult, and the effect of this invention can be anticipated more.

Furthermore, the semiconductor device of the present invention, the lead electrodes have different respective widths, it is preferable to have a groove or protrusion only those larger the width. In some cases, the widths of the lead electrodes are made different from the viewpoint of heat dissipation and mountability of the light emitting element. Naturally, as the width of the lead electrode becomes wider, the gap formed at the interface between the package member and the lead electrode becomes larger, and the mold member is more likely to leak. Therefore, by providing the groove or protrusion only on the wide lead electrode, it is possible to prevent the mold member from leaking.

Furthermore, in the semiconductor device of the present invention , the package member is preferably a polyamide-based synthetic polymer. Polyamide-based synthetic polymer moldability, while suitably used as a package member in view of durability, because unfavorable adhesion, adhesion between the lead electrodes, gaps are likely to occur at the interface between the lead electrode. Therefore, a great effect can be expected by applying the present invention.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the modes shown below exemplify a semiconductor device for embodying the technical idea of the present invention, and the present invention does not limit the semiconductor device to the following. Further, the size and positional relationship of the members shown in the drawings are exaggerated for clarity of explanation.

  Embodiments according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a surface mount type (SMD type) semiconductor device . (A) is a front view common to the present invention and the prior art, (b) is a sectional view according to the present invention, (c) is a view of only the lead electrode of (b), and (d) is another view of the present invention. Sectional drawing which concerns on embodiment, (e) is the figure which extracted only the lead electrode of (d), (f) is sectional drawing which concerns on a prior art, (g) is the figure which extracted only the lead electrode of (f). is there.

  Since the characteristic part of the present invention is covered with the package member, when the package member is made of an opaque material, it is apparently the same as the prior art.

The semiconductor device requires at least the following configuration. At least one light emitting element, a package member, a plurality of lead electrodes , and a mold member. In some cases, a fluorescent material or an inner lead electrode is required.

  The constituent members will be briefly described below.

( Lead electrode )
The lead electrode 1 includes a first part 1 ′ partially exposed in the recess of the package member, a second part 1 ″ covered by the package member, and a first part protruding from the outer wall surface of the package member. It consists of three parts of three parts 1 ′ ″.

The first part partially exposed in the recess of the package member refers to a lead electrode portion located in the recess formed by the package member.

The 2nd site | part coat | covered with a package member means the lead electrode part covered with the package member.

The third portion protruding from the outer wall surface of the package member refers to a lead electrode portion that is not covered by the package member.

Grooves and protrusions, which are characteristic portions of the present invention, are formed in the second portion covered by the package member. The direction of forming the groove and the protrusion extends in the direction perpendicular to the extending direction of the lead electrode as can be seen from FIGS. 1B, 1C, 1D, and 1E.

When the groove is provided, the mold member leaking from the interface between the lead electrode and the package member from the recess can be stored in the groove, so that the mold member can be prevented from leaking outside the package member.

When the protrusion is provided, the mold member leaking from the interface between the lead electrode and the package member from the recess can be blocked by the protrusion, so that the mold member can be prevented from leaking outside the package member. I can do it.

Further, regardless of which structure is adopted, the bonding area between the lead electrode and the package member increases, so that the bonding strength is improved and the gap at the interface is reduced. When the gap at the interface is reduced, the mold member is less likely to leak out.

  These synergistic effects solve the problem of mold member leakage.

  The method of forming the groove and the protrusion is formed by punching (pressing) or etching.

The material of the lead electrode may be any material as long as it has conductivity, and any metal can be used, but it is an alloy based on Cu from the viewpoint of conductivity, heat dissipation, mechanical strength, light reflection, etc. A surface treated with Ag is preferred.

(Package material)
Since it is constituted by injection molding, all resins used for injection molding can be used, but a polyamide-based synthetic polymer is preferably used from the viewpoint of heat resistance and moldability. The package member forms a recess for mounting the light emitting element.
The concave portion refers to a concave portion where the light emitting element is mounted and the mold member is sealed.

(Mold member)
The property required for the mold member is to be translucent. In order to increase the light extraction efficiency, a material having a refractive index smaller than that of the light emitting element is preferable. When light emitted from the semiconductor device emits a mixed color instead of a single color, a light diffusing agent may be mixed to improve color mixing. The light diffusing agent needs to have a refractive index difference from the mold member and be translucent. The material of the light diffusing member is not particularly limited, and various materials such as barium titanate, barium sulfate, titanium oxide, aluminum oxide, silicon oxide, light calcium carbonate, and heavy calcium carbonate can be used. As a material of the mold member, an epoxy resin, an acrylic resin, a urethane resin, a difuryl phthalate resin, a silicone resin, a low melting point glass, or the like is preferably used.

(Light emitting element)
In the light emitting element, a semiconductor such as GaAs, InP, GaAlAs, AlInGaP, InN, AlN, GaN, InGaN, or AlInGaN is formed as a light emitting layer on a substrate by MOCVD or the like. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, and a PN junction, a heterostructure, and a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and its crystallinity.

  When a gallium nitride compound semiconductor is used, a material such as sapphire, spinel, SiC, Si, ZnO, or GaN is preferably used for the semiconductor substrate. The gallium nitride compound semiconductor exhibits n-type conductivity when not doped with impurities. In order to make it more n-type, n-type dopants such as Si, Ge, Se, Te, and C are appropriately introduced. On the other hand, when a p-type gallium nitride semiconductor is formed, a p-type dopant such as Zn, Mg, Be, Ca, Sr, Ba, or the like is doped.

  Since a gallium nitride compound semiconductor is difficult to become p-type only by doping with a p-type dopant, it is made more p-type by annealing.

  When an insulating substrate such as a sapphire substrate is used, n-type and p-type layers with different polarities are exposed on the same surface side by an etching process or the like to form electrodes. When a conductive substrate such as a SiC substrate is used, electrodes can be formed on the substrate side and the gallium nitride layer growth surface side, respectively.

  A light emitting element can be obtained by mechanically chipping the semiconductor wafer obtained as described above.

(Inner lead electrode)
In order to electrically connect the light emitting element to the lead electrode, a wire bond electrode is used as the inner lead electrode. The diameter of the wire is preferably 25 μm to 35 μm. As a material, Au, Cu, Pt, Au or the like is preferably used.

(Fluorescent substance)
A fluorescent material that converts light from the light emitting element into a longer wavelength is good in luminous efficiency. The mixed color light whose wavelength is converted by the light emitting element and the fluorescent material is preferably white.

  The fluorescent material preferably has a center particle size in the range of 6 μm to 50 μm, more preferably 15 μm to 30 μm, and the fluorescent material having such a particle size has high light absorption and conversion efficiency, and Wide excitation wavelength range. Fluorescent materials smaller than 6 μm are relatively easy to form aggregates and are densely settled in the liquid resin, reducing the light transmittance and reducing the light absorptivity and conversion efficiency. The excitation wavelength is also narrow.

(Yttrium / aluminum oxide phosphor)
The fluorescent material used in this embodiment is excited by light emitted from a light emitting element having a nitride semiconductor as a light emitting layer, emits light, and is activated by cerium (Ce) or praseodymium (Pr). A phosphor based on an aluminum oxide phosphor (YAG phosphor) can be obtained. Specific examples of the yttrium / aluminum oxide fluorescent material include YAlO ₃ : Ce, Y ₃ Al ₅ O ₁₂ : Ce (YAG: Ce), Y ₄ Al ₂ O ₉ : Ce, and mixtures thereof. It is done. The yttrium / aluminum oxide fluorescent material may contain at least one of Ba, Sr, Mg, Ca, and Zn. Further, by containing Si, the crystal growth reaction can be suppressed and the fluorescent substance particles can be aligned. More specifically, the general formula _{(Y z Gd 1-z)} 3 Al 5 O 12: Ce ( where, 0 <Z ≦ 1) photoluminescence phosphor and the general formula represented by _{(Re 1-a Sm a)} 3 Re ' ₅ O ₁₂ : Ce (where 0 ≦ a <1, 0 ≦ b ≦ 1, Re is at least one selected from Y, Gd, La, and Sc, and Re ′ is selected from Al, Ga, and In At least one kind of photoluminescent phosphor. Further, in addition to Ce, Tb, Cu, Ag, Au, Fe, Cr, Nd, Dy, Co, Ni, Ti, Eu and the like can be contained as desired.

In the package member of the present invention, such a photoluminescent phosphor may be a mixture of yttrium / aluminum / garnet phosphors activated with two or more kinds of cerium and other phosphors. By mixing two types of yttrium / aluminum / garnet phosphors with different amounts of substitution from Y to Gd, light having a desired color tone can be easily realized.

Example 1
The external dimensions of the semiconductor device in Example 1 of the present invention are the x-direction: 4.7 mm, the y-direction: 1.2 mm, and the z-direction 1.5 mm, and the shape is the side view type shown in FIG. Is. Three light emitting elements are mounted, and the light emission colors are different from each other. Blue, Red, and Green, which are the three primary colors of light, are used. Gallium nitride compound semiconductors were used for Blue and Green, and AlInGaP compound semiconductors were used for Red. The brightness was adjusted to be white light when Blue was set to 200 mcd, Green was set to 900 mcd, and Red was set to 290 mcd.

As the lead electrode , a Cu alloy whose surface was treated with Ag was used, and a groove having a thickness of 0.025 mm was formed with respect to a thickness of 0.125 mm.

A polyamide-based synthetic polymer was used as the package member, a silicone resin was used as the mold member , and Au was used as the wire bond electrode material of the inner lead electrode. In the semiconductor device obtained by the above configuration, the mold member did not leak out of the package member.

(Example 2)
All the light-emitting elements shown in FIG. 1 are made of blue gallium nitride compound semiconductor, YAG is used as a fluorescent material, and white is obtained as mixed color light. Except for forming a 0.025 mm protrusion on the lead electrode , the structure was the same as in Example 1. In the semiconductor device obtained by the above configuration, the mold member did not leak out of the package member .

  INDUSTRIAL APPLICABILITY The present invention can be used for a liquid crystal backlight that is remarkably required to be thin and light.

FIG. 1A is a front view of a semiconductor device according to an embodiment of the present invention and the related art. FIG. 1B is a cross-sectional view taken along line AA of the semiconductor device according to the embodiment of the present invention. FIG. 1C shows only the lead electrode shown in FIG. FIG. 1D is a cross-sectional view taken along line AA of the semiconductor device according to another embodiment of the present invention. FIG. 1E shows only the lead electrode shown in FIG. FIG. 1F is a cross-sectional view taken along line AA of the semiconductor device according to the embodiment of the prior art. FIG. 1G shows only the lead electrode shown in FIG. It is a perspective view of a semiconductor device of an embodiment concerning the present invention and a prior art. FIG. 3 is a perspective view of the semiconductor device according to the embodiment of the present invention and the prior art from an angle different from that in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lead electrode 1 '... 1st site | part 1''partially exposed in a recessed part ... 2nd site | part 1''' ... package covered with a package member 3rd part 3 projected from the outer wall surface of a member ... Light emitting element 5 ... Recessed part 7 ... Package member 9 ... Mold member 11 ... Groove part 13 ... Projection part 17 ... Inner lead electrode 100... Semiconductor device

Claims (8)

A light emitting element, a package member made of a resin having a recess in which the light emitting element is arranged, and an outer lead electrode electrically connected to the light emitting element, and the light emitting element covered in the recess In a semiconductor device having a mold resin to be
The outer lead electrode protrudes from the outer wall surface of the package member, a first portion that is partially exposed in the recess, a second portion that is covered by the package member, and an outer wall surface of the package member. A third part in order,
Second part of the outer lead electrodes may have a groove portion serving as a barrier mold member leaking from the interface between the package member and the outer lead electrodes to the outer wall surface direction of the package member, the mold member groove A semiconductor device that is stored in a semiconductor device. The semiconductor device according to claim 1, wherein the semiconductor device is a type in which a light emitting surface is perpendicular to a mounting surface. The semiconductor device according to claim 1, wherein the light emitting elements are a plurality of light emitting elements having different emission colors. The outer lead electrodes are different each width, the semiconductor device of claims 1 to 3, wherein a groove portion only in larger of said width. The semiconductor device according to claim 1, wherein the package member is a polyamide-based synthetic polymer. The semiconductor device according to claim 1, wherein the outer lead member is a Cu alloy and the surface thereof is Ag-plated. The semiconductor device according to claim 1, wherein the mold member is silicone. The semiconductor device according to claim 1, wherein when the light emitting element has a wire bond electrode that is an inner lead electrode from the same surface side, the height of the wire is different between the p electrode side and the n electrode side.

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