JP2007273765A - Manufacturing method of semiconductor light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor light-emitting device having proper transferability. <P>SOLUTION: After fixing a light emitter 10 to a fixture 124, mixed solution 20B is poured to a plentiful degree into the inside of a mold. Then, in a state of applying pressure higher than the atmospheric pressure to the interface of the mixed solution 20B inside the mold, the mixed solution 20B inside the mold is heated and cured so that a sealing part 20 is obtained from the mixed solution 20B. Consequently, for as long as the mixed solution 20B is carrying out contraction curing in the mold, the mixed solution 20B can be pressed against the mold inner wall. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor light emitting device provided with a sealing portion that also serves as a lens.

  A semiconductor light emitting device such as a light emitting diode (LED) can take various configurations depending on its application. For example, the semiconductor light emitting device includes a semiconductor light emitting element with a lead and a sealing portion that covers a semiconductor chip. There is something. This semiconductor light emitting device is mainly applied to a lighting device, and the sealing portion not only protects the semiconductor chip from the external environment but also serves as a lens (Patent Document 1).

JP-A-57-202701

  As described above, when the sealing portion is also used as a lens, as a material of the sealing portion, for example, a thermosetting resin (refractive index having a high refractive index as described in Patent Literature 1 to Patent Literature 4). (Rate n2 = 1.6 to 1.8) may be used. However, since this thermosetting resin has a property of shrinking and curing by heating, for example, as shown in FIGS. 10 (A) to 10 (C), the thermosetting as described above is performed by a casting mold. The resin 100 is poured into the mother mold 110, and then the semiconductor light emitting device 120 with the lead frame attached to the semiconductor chip is immersed in the thermosetting resin 100 in the mother mold 110, and the thermosetting resin 100 is cured by heating and sealed. When the stop portion 130 is formed, shrinkage deformation called “sink” occurs in the sealing portion 130, and transferability from the mother die to the sealing portion 130 deteriorates.

  Here, comparing the ideal shape of the sealing portion 130 formed by the mother die with the shape of the sealing portion 130 obtained by molding, the amount of displacement at the largest displacement portion is determined as the sealing portion 130. If the value divided by the distance from the center of gravity is defined as the amount of deviation due to “sinking”, the amount of deviation is theoretically about 0.1% to 5%. Therefore, in applications that require accurate light distribution control of light output from the semiconductor light emitting device 120, shrinkage deformation due to “sink” may not be allowed.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a method for manufacturing a semiconductor light-emitting device with good transferability.

The manufacturing method of the semiconductor light-emitting device of the present invention is shown below after preparing a mother die having a transmission path for transmitting pressure inside and a fixing part for fixing the semiconductor light-emitting element inside ( Steps A) to (D) are performed.
(A) The step of fixing the semiconductor light emitting element to the fixing part (B) The step of injecting a transparent thermosetting resin into the mother mold (C) The semiconductor light emitting element is fixed to the fixing part and the thermosetting inside the mother mold A step of applying a pressure higher than the atmospheric pressure to the inside of the mother mold through the transmission path in a state where the functional resin is injected (D) a thermosetting inside the mother mold in a state of applying a pressure higher than the atmospheric pressure Heating and curing the functional resin

  In the method of manufacturing a semiconductor light emitting device according to the present invention, the thermosetting resin is shrink-cured in a state where a pressure higher than the atmospheric pressure is applied to the inside of the mother die, so that the inner wall of the mother die is thermally cured. The functional resin is pressed.

  According to the method for manufacturing a semiconductor light emitting device of the present invention, the thermosetting resin is shrink-cured in a state where a pressure higher than the atmospheric pressure is applied to the thermosetting resin inside the mother die. The thermosetting resin can be pressed against the inner wall. As a result, there is no possibility of “sinking” occurring, so that the transfer property from the mother die to the sealing portion is extremely improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional structure of a light-emitting diode 1 (semiconductor light-emitting device) according to an embodiment of the present invention. Note that FIG. 1 is a schematic representation and is different from actual dimensions and shapes. The light-emitting diode 1 includes a sealing unit 20 on a light-emitting unit 10 (semiconductor light-emitting element). Here, the light emitting unit 10 is configured by placing a semiconductor chip 12 on a lead frame 11.

  The lead frame 11 is a metal frame for mounting the semiconductor chip 12. For example, a die pad portion (not shown) for mounting and fixing the semiconductor chip 12, an n-side electrode of the semiconductor chip 12, and It has an internal terminal portion (not shown) connected to a p-side electrode (described later), and an external terminal portion 11A that protrudes from the surface opposite to the semiconductor chip 12 and is connected to the internal terminal portion. The inner terminal portion of the lead frame 11 and the electrode of the semiconductor chip 12 are electrically connected by, for example, a wire (not shown).

  The semiconductor chip 12 includes, for example, an n-type semiconductor layer (not shown), an active layer (not shown) including a light emitting region, and a p-type semiconductor layer (not shown) on a substrate 12A (see FIG. 2). It is constructed by stacking in order. The semiconductor chip 12 also includes an n-side electrode (not shown) electrically connected to the n-type semiconductor layer and a p-side electrode (not shown) electrically connected to the p-type semiconductor layer. Is provided. Here, the substrate 12A is provided on the opposite side of the semiconductor chip 12 from the lead frame 11, and is made of a material that can transmit light from the light emitting region, for example, sapphire. That is, the semiconductor chip 12 is a top emission type light emitting element capable of outputting light from the light emitting region from the substrate 12A side (upper surface side). Each of the n-type semiconductor layer, the active layer, and the p-type semiconductor layer is made of, for example, a GaN-based or InGaN-based semiconductor material. The p-side electrode has a structure in which, for example, titanium (Ti), platinum (Pt), and gold (Au) are stacked in this order, and the n-side electrode is, for example, an alloy of Au and germanium (Ge), It has a structure in which nickel (Ni) and Au are laminated in this order.

  The sealing unit 20 is provided on the light emitting unit 10 on the semiconductor chip 12 side, and is, for example, a polyhedron having an obtuse angle or a solid body having a rotationally symmetric axis and a curved surface shape represented by a general aspheric type. . The semiconductor chip 12, the die pad portion and inner terminal portion of the lead frame 11, and the wire are embedded in the central portion on the flat side of the hemisphere, and the external terminal portion 11 A protrudes from the sealing portion 20. Thereby, the sealing unit 20 not only protects the semiconductor chip 12 and the like from the external environment, but also functions as a lens.

  The sealing unit 20 is made of a thermosetting resin having a high refractive index (refractive index n2 = 1.6 to 1.8). Examples of such a high refractive index thermosetting resin include epoxy resins containing sulfur and cyclic hydrocarbon groups, silicon resins, acrylic resins, urethane resins, and polythiourethane resins. This thermosetting resin is obtained by curing a mixed solution 20B (see FIG. 4B) of a monomer thermosetting resin and a polymerization catalyst by a polymerization reaction. Thus, the surface of the semiconductor chip 12 on the light emission side (the surface of the substrate 12A) is higher than a refractive index (refractive index n3 = 1.5) such as epoxy resin or silicon resin, for example, sapphire (refractive index n1 = 1.76) (see FIG. 2), light is sealed from the substrate 12A side as compared with the case where a low refractive index material such as epoxy resin or silicon resin is used as the material of the sealing portion 20. When proceeding to the portion 20 side, the critical angle at the interface 12B between the substrate 12A and the sealing portion 20 becomes extremely large. When the surface of the substrate 12A is made of a material having a refractive index lower than that of the sealing portion 20, when the light travels from the substrate 12A side to the sealing portion 20 side, it is not totally reflected at the interface 12B.

  By the way, in order to function as a lens for controlling the light distribution of all the light output from the semiconductor chip 12, the sealing portion 20 is molded into a lens shape as a whole with a mother die as will be described later. Is. In order to perform light distribution control, it is necessary that the sealing portion 20 is formed with a predetermined accuracy. For example, in an application in which a deviation amount of about several percent is not acceptable, the mother die is accurate. Even if it is well formed, “sinks” that occur during molding can be a problem. This “sink” is caused by shrinkage hardening of the mixed solution 20B. Since the hardening of the mixed solution 20B usually proceeds from the portion in contact with the matrix, the whole is hardened through a state where the outer side is hard and the inner side is soft. Thus, when solidifying from the outside to the inside, “sinking” occurs due to the effect of curing shrinkage. Here, in the case of the mother mold as shown in FIG. 10, since the mixed solution is pressed against the inner wall of the mother mold by the action of gravity, the influence of “sink” is relatively small. For example, as in this embodiment In addition, when using a separation type mother mold in which the upper surface side mother mold 110 and the lower surface side mother mold 120 (see FIGS. 3A and 3B) are overlapped with each other and the entire outer shape is molded into a lens shape, The “sink” is prominently generated in the upper part of the mother die which is hardly affected by gravity. Therefore, in the present embodiment, a pressure higher than the atmospheric pressure is applied to the mixed solution 20B injected into the mother die, and the entire mixed solution 20B is pressed against the inner wall of the mother die. The details will be described in the following manufacturing process.

  Next, an example of the manufacturing method of the light emitting diode 1 of this Embodiment is demonstrated with reference to FIG. 3 (A), (B)-FIG. 3A shows a cross-sectional configuration of a mold or the like in the manufacturing process (a cross-sectional configuration in the direction of arrows AA in FIG. 3B), and FIG. 3B is a cross-sectional view of FIG. It is a top view. 4A and 4B to FIG. 5A and FIG. 5B show cross-sectional configurations of a mold and the like for explaining each manufacturing process. FIG. 6 is a flowchart of the method for manufacturing the light-emitting diode 1.

  Since the light emitting unit 10 can be manufactured by a known manufacturing method, description of the manufacturing method is omitted, and an example of a process of providing the sealing unit 20 in the light emitting unit 10 will be described below. .

  Now, when the sealing portion 20 is provided in the light emitting portion 10, a separation type matrix as shown in FIGS. 3A and 3B is used. This mother die includes an upper surface side mother die 110 and a lower surface side mother die 120. Here, the upper surface side mold 110 is provided with a molding recess 111 at the center and a sealing ring 112 at the outer edge. The sealing ring 112 is for preventing the mixed solution 20B from leaking out from the inside of the matrix, and is, for example, an elastomer seal or a metal O-ring. On the other hand, the lower surface side master die 120 has a molding recess 121 corresponding to the recess 111 of the upper surface side master die 110, and the sealing ring 112 corresponding to the seal ring 112 of the upper surface side master die 110. Recesses 122 for engaging each other are provided. Instead of the recess 122, a flat flange such as a general JIS flange may be provided. The lower surface side mold 120 is also provided with a notch 123 (transmission path) at the outer edge and a fixing portion 124 at the bottom of the recess 122. The notch 123 serves as a passage for electrically connecting the inside and the outside of the mother die when the upper surface side mother die 110 and the lower surface side mother die 120 are overlapped with each other to form a container. Therefore, the notch 123 is used to inject the mixed solution 20B from the outside of the mother die into the inside thereof, or to apply pressure to the mixed solution 20B injected into the inside of the mother die (see FIG. 5A). ) Can be inserted and has a diameter and shape (for example, a semi-cylindrical shape). The fixing portion 124 is for fixing the light emitting portion 10 inside the mother die, and includes, for example, a hole having a diameter capable of fixing the external terminal portion 11A of the light emitting portion 10 by fitting. In order to prevent the mixed solution 20B from flowing into the fixing portion 124, for example, a sealing ring (not shown) may be provided at the entrance of the hole. Although not shown in the figure, this matrix is disposed in the chamber. A heating / cooling device (not shown) for heating / cooling is provided in the chamber, and the mixed solution 20B in the mother mold can be heated / cooled using the heating / cooling device.

  First, after fixing the light emitting part 10 to the fixing part 124 of the lower surface side mold 120, the upper surface side mold 110 and the lower surface side mold 120 are overlapped with each other to make the inside of the mother mold airtight (step S1, FIG. 4). (A)). Subsequently, the mixed solution 20B is discharged from the resin injector 130 and injected into the mold through the notch 123 (step S2, FIG. 4B). At this time, the amount of shrinkage due to heating of the mixed solution 20B is estimated, and a large amount is injected. That is, the mixed solution 20B in an amount exceeding the volume excluding the notch 123 is injected into the mother die. In addition, since the mixed solution 20B injected into the mother mold is defoamed in advance, there is no possibility that the mixed solution 20B contains bubbles before being injected into the mother mold.

  Next, the pressure pin 141 of the pressure device 140 is inserted into the notch 123, and a pressure higher than the atmospheric pressure is applied to the interface of the mixed solution 20B in the mold (step S3, FIG. 5A). . As a result, the entire mixed solution 20B is pressed against the inner wall of the matrix and the surface of the light emitting unit 10. Subsequently, in this state, the mixed solution 20B is heated and polymerized and cured for a predetermined period while performing appropriate temperature control in the temperature range from about 40 ° C. to about 150 ° C. using a heating / cooling device (step S4). ). After that, the mother die is opened and the light emitting diode 1 is taken out (FIG. 5B). In this way, the light emitting diode 1 of the present embodiment is manufactured.

  Next, operations and effects of the light-emitting diode 1 of the present embodiment will be described. In the light emitting diode 1, when a predetermined voltage is applied between the p-side electrode and the n-side electrode, electrons are injected from the n-side electrode and holes are injected from the p-side electrode into the active layer. Then, electrons and holes injected into the active layer are recombined to generate photons from the active layer, and as a result, emitted light is emitted from the back surface of the substrate 12A through the sealing portion 20 to the outside. .

  Here, if a material with a low refractive index (n3 = about 1.5) such as an epoxy resin or a silicon resin is used as the material of the sealing portion 20, the refractive index n1 is, for example, as the substrate 12A of the semiconductor chip 12. When sapphire of about 1.76 is used, as shown in FIG. 2A, the refractive index difference at the interface 12B increases. Therefore, when the light travels from the substrate 12A side to the sealing portion 20 side, the critical angle at the interface 12B decreases, so that the ratio of total reflection or Fresnel reflection at the interface 12B increases. As a result, most of the reflected light is absorbed by the active layer or the like in the semiconductor chip 12, so that the light extraction efficiency is low when such a configuration is adopted.

  On the other hand, in the present embodiment, since the thermosetting resin having a high refractive index (having a refractive index n2 of about 1.6 or more and 1.8 or less) is used as the material of the sealing portion 20, the semiconductor chip 12 is used. When a material having a higher refractive index (refractive index n3 = about 1.5) such as epoxy resin or silicon resin, for example, sapphire having a refractive index n1 of about 1.76, is used as the substrate 12A. Compared with the case where a low refractive index material such as epoxy resin or silicon resin is used as the material, the critical angle at the interface 12B is made extremely large when light travels from the semiconductor chip 12 side to the sealing portion 20 side. Can do. Therefore, the ratio of the light traveling from the substrate 12A side to the sealing portion 20 side being totally reflected or causing Fresnel reflection at the interface 12B can be extremely reduced, so that the light extraction efficiency can be improved. When a material having a refractive index lower than that of the sealing portion 20 is used as the substrate 12A of the semiconductor chip 12, the light is totally reflected at the interface 12B when the light travels from the substrate 12A side to the sealing portion 20 side. Since this is not the case, the reduction in the extraction efficiency is small as compared with the case where the refractive index of the substrate 12A is higher than that of the sealing portion 20.

  Note that the above operations and effects are based on the premise that the substrate 12A and the sealing portion 20 are in contact with each other without a gap, as shown in FIG. That is, if there is a gap even between submicrons between the substrate 12A and the sealing portion 20, the critical angle is defined by the relationship between the substrate 12A and the gap. Even if a high thermosetting resin is used, the light extraction efficiency cannot be improved. On the other hand, in the present embodiment, the light emitting unit 10 is placed in the mixed solution 20B, and the mixed solution 20B is shrink-hardened in a state where a pressure higher than the atmospheric pressure is applied to the interface of the mixed solution 20B in the mold. Since it did in this way, there is no possibility that a space | gap may arise between board | substrate 12A and the sealing part 20. FIG. Therefore, the light extraction efficiency can be improved with certainty.

  In the present embodiment, the mixed solution 20B is contracted and cured in a state where a pressure higher than the atmospheric pressure is applied to the interface of the mixed solution 20B in the mold. The mixed solution 20B can be pressed against the inner wall of the mother mold throughout the shrinkage hardening. As a result, there is no possibility of “sinking”, and the transferability from the mother die to the sealing portion 20 is extremely improved. As a result, the light output from the light emitting unit 10 can be accurately controlled.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the above embodiment, the pressure pin 141 of the pressurizer 140 is inserted into the notch 123 to apply pressure to the interface of the mixed solution 20B, but other methods, for example, FIG. As shown in FIG. 6, pressure is applied to the interface of the mixed solution 20B by injecting into the notch 123 a gas that does not inhibit the hardening of the mixed solution 20B, such as nitrogen gas or argon gas, from the gas injector 150. May be.

  Moreover, in the said embodiment, although the shape of the sealing part 20 was made into the polyhedron which consists of an obtuse angle, of course, it can be set as another shape. For example, as shown in FIG. 8, the shape of the sealing portion 20 may be a polyhedron having an aspherical surface and a flat surface. However, in this case, as shown in FIG. 9, a mold having an aspheric surface is required. However, if there is an acute-angled area inside the mold, “sinking” is likely to occur in that area. . However, as in the above embodiment, when the mixed solution 20B is shrink-cured with a pressure higher than the atmospheric pressure applied to the interface of the mixed solution 20B in the mold, “sinking” occurs. There is no fear, and transferability from the mother die to the sealing portion 20 can be extremely improved.

  In the above embodiment, the case where the present invention is applied to the light-emitting diode 1 having a semiconductor chip on the lead frame has been described. However, other types of light-emitting diodes, for example, a semiconductor on an intermediate board or a printed board. Of course, the present invention can also be applied to a light-emitting diode configured by flip-chip connecting chips.

  In the above embodiment, the case where the present invention is applied to a light-emitting diode has been described. However, the present invention is not limited to this, and can be applied to other semiconductor light-emitting devices.

It is a section lineblock diagram of a light emitting diode concerning one embodiment of the present invention. It is a distribution map of the refractive index in the interface of a board | substrate and a sealing part, and its vicinity. FIG. 2 is a cross-sectional configuration diagram for explaining a manufacturing process of the light emitting diode of FIG. 1. FIG. 4 is a cross-sectional configuration diagram for explaining a manufacturing process continued from FIG. 3. FIG. 5 is a cross-sectional configuration diagram for explaining a manufacturing process continued from FIG. 4. It is a flowchart for demonstrating the manufacturing process of the light emitting diode of FIG. It is a cross-sectional block diagram for demonstrating the other manufacturing method of a light emitting diode. It is a cross-sectional block diagram of the light emitting diode which concerns on one modification. FIG. 8 is a cross-sectional configuration diagram for explaining a manufacturing process of the light-emitting diode of FIG. 7. It is a cross-sectional block diagram for demonstrating the manufacturing method of the conventional light emitting diode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light emitting diode, 10 ... Light emission part, 11 ... Lead frame, 11A ... External terminal part, 12 ... Semiconductor chip, 12A ... Substrate, 12B ... Interface, 20 ... Sealing part, 20B ... Mixed solution, 110 ... Upper surface side mother Die, 111 ... depression, 112 ... ring, 120 ... lower surface side mold, 121, 122 ... depression, 123 ... notch, 124 ... fixing part, 130 ... resin injector, 140 ... pressurizer, 141 ... pressurization pin, 150: Gas injector.

Claims (4)

A step of fixing the semiconductor light emitting element to the fixing portion of the mother die having a transmission path for transmitting pressure inside and a fixing portion for fixing the semiconductor light emitting element inside;
Injecting a transparent thermosetting resin into the matrix;
A pressure higher than atmospheric pressure is applied to the inside of the mother mold through the transmission path in a state where the semiconductor light emitting element is fixed to the fixing portion and a thermosetting resin is injected into the mother mold. Steps,
And heating and curing the thermosetting resin inside the matrix while applying a pressure higher than the atmospheric pressure. A method for manufacturing a semiconductor light emitting device, comprising: The thermosetting resin in an amount exceeding the volume excluding the introduction path and the transmission path inside the mother mold is injected into the mother mold to which the semiconductor light emitting element is fixed. A method for manufacturing a semiconductor light emitting device according to claim 1. 2. The semiconductor light emitting device according to claim 1, wherein a pressure higher than an atmospheric pressure is applied to the thermosetting resin injected into the matrix by inserting a pressure pin into the transmission path. Production method. 2. The semiconductor light emitting device according to claim 1, wherein a pressure higher than an atmospheric pressure is applied to the thermosetting resin injected into the matrix by injecting an inert gas into the transmission path. Production method.

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