Optoelectronic component comprising a bonding layer and method for producing a bonding layer in an optoelectronic component

Abstract

An optoelectronic component and a method for manufacturing an optoelectronic component are provided. In an embodiment, the optoelectronic component includes a layer sequence having an active layer configured to emit electromagnetic primary radiation, a converter lamina disposed in a beam path of the electromagnetic primary radiation and a bonding layer disposed between the layer sequence and the converter lamina, wherein the bonding layer comprises an inorganic-organic hybrid material having Si—O—Al bonds and/or Si—O—Zr bonds.

Claims

1. A method for producing a bonding layer comprising an inorganic-organic hybrid material between a layer sequence having an active layer and a converter lamina in an optoelectronic component, the method comprising: providing the layer sequence having the active layer and the converter lamina; producing an adhesive; applying the adhesive to the layer sequence or to the converter lamina; positioning the converter lamina atop the layer sequence or positioning the layer sequence atop the converter lamina; and curing the adhesive to form the bonding layer, wherein producing the adhesive comprises: providing a first reaction mixture comprising at least one compound of the formula III or at least one compound of the formula III and a compound of the formula IV: ##STR00018## wherein, in formula III: R′ is hydrogen and/or an organic radical, and R″ is an organic radical having an epoxy group or an organic radical having an isocyanate group, and wherein, in formula IV: M′=Si or Zr, m′=0, 1, 2, 3, 4 or 5, R′″ is hydrogen and/or an organic radical, adding a solution comprising a compound of the formula I and a compound of the formula II dropwise to the first reaction mixture to form a second reaction mixture: ##STR00019## wherein, in formula I: M=Al or Zr, R is hydrogen and/or an organic radical, and x=3 or 4, and wherein, in formula II: R.sup.1 and R.sup.2 may be chosen identically or differently and are each hydrogen and/or an organic radical.

2. The method according to claim 1, wherein the compound of the formula I and the at least one compound of the formula III are used in a molar ratio of 1:1 to 1:10.

3. The method according to claim 1, further comprising adding an acid to the second reaction mixture to form a third reaction mixture after adding the solution.

4. The method according to claim 1, wherein the following applies to the at least one compound of the formula III: R′ is selected from a group comprising hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl and phenyl radicals and combinations thereof.

5. The method according to claim 1, wherein the at least one compound of the formula III has the following formula IIIa: ##STR00020## wherein m=0, 1, 2, 3, 4 or 5.

6. The method according to claim 1, wherein, while providing the first reaction mixture, the first reaction mixture comprises a first compound and a second compound of the formula III or a first compound and a second compound of the formula III and a compound of the formula IV, and wherein the following applies to the first compound of the formula III: R″ is an organic radical having an epoxy group, and the following applies to the second compound of the formula III: R″ is an organic radical having an isocyanate group.

7. The method according to claim 6, wherein the first compound of the formula III has the following formula IIIa and the second compound of the formula III has the following formula IIId: ##STR00021## wherein R′ is independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl and phenyl radicals and combinations thereof, n=1, 2, 3, 4 or 5, and m=0, 1, 2, 3, 4 or 5.

8. The method according to claim 1, wherein the compound of the formula I has the following formula Ia or Ib:
Al(OR).sub.3  Formula Ia
Zr(OR).sub.4  Formula Ib, wherein R is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl and phenyl radicals and combinations thereof.

9. The method according to claim 1, wherein the following applies to the compound of the formula I: M=Al, x=.sub.3, and R is selected from a group comprising hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl and phenyl radicals and combinations thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments and developments of the invention are apparent from the working examples described hereinafter in conjunction with the figures.

(2) FIGS. 1 and 2 show schematic side views of various embodiments of optoelectronic components,

(3) FIG. 3 shows the thermal conductivity of each of two silicon wafers bonded with a bonding layer.

(4) In the working examples and figures, constituents that are identical or have the same effect are each given the same reference numerals. The elements shown and their ratios of size with respect to one another should not be regarded as being to scale; instead, individual elements, especially layer thicknesses, may be shown in an exaggerated size for better understanding.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(5) The optoelectronic component 1 according to FIG. 1 shows a carrier 5 with a leadframe 6. Disposed atop the carrier 5 is a layer sequence 4 electrically connected to the leadframe 6 via bonding wires 7. Disposed above the layer sequence 4 is a converter lamina 3. The converter lamina 3 comprises converter particles and an inorganic-organic hybrid material or converter particles and a silicate glass, with the converter particles distributed homogeneously, for example, within the inorganic-organic hybrid material or within the silicate glass. The converter lamina 3 is disposed in the beam path of the electromagnetic primary radiation which is emitted by an active layer (not shown here) in the layer sequence 4. Disposed between the layer sequence 4 and the converter lamina 3 is a bonding layer 2. The bonding layer 2 comprises an inorganic-organic hybrid material having Si—O—Si, Si—O—Al and Al—O—Al bonds or Si—O—Si, Si—O—Zr and Zr—O—Zr bonds. The bonding layer 2 can be produced as follows:

(6) A) providing a layer sequence (4) having an active layer and a converter lamina (3),

(7) B) producing an adhesive,

(8) C) applying the adhesive to the layer sequence (4) or to the converter lamina (3),

(9) D) positioning the converter lamina (3) atop the layer sequence (4) or positioning the layer sequence (4) atop the converter lamina (3),

(10) E) curing the adhesive to form the bonding layer (2),

(11) where process step B) comprises the following process steps:

(12) B1) providing a first reaction mixture comprising a compound of the formula IIIa

(13) ##STR00012##

(14) where R′ is selected from a group comprising hydrogen, methyl, ethyl, propyl and isopropyl radicals and combinations thereof and m=0, 1, 2, 3, 4 or 5,

(15) B2) adding a solution comprising a compound of the formula I and a compound of the formula II dropwise to the first reaction mixture

(16) ##STR00013##

(17) where, in formula I:

(18) M=Al or Zr,

(19) R is selected from a group comprising hydrogen, methyl, ethyl, propyl, isopropyl and sec-butyl radicals and combinations thereof,

(20) and x=3 when M=Al or x=4 when M=Zr;

(21) and where, in formula II:

(22) R.sup.1 is selected from a group comprising hydrogen, methyl, ethyl, propyl and isopropyl radicals and combinations thereof. R.sup.2 is selected from a group comprising methoxy, ethoxy, propoxy and isopropoxy radicals and combinations thereof.

(23) Preferably, the optoelectronic component 1 is an LED, wherein the radiation in the figure is coupled out in the upward direction through a transparent layer sequence 4, the transparent bonding layer 2 and the transparent converter lamina 3.

(24) The optoelectronic component 1 according to FIG. 2 exhibits a carrier 5 with a leadframe 6 and a housing 8. The housing 8 has, in the middle, a recess with the layer sequence 4 electrically connected to the leadframe 6 disposed therein. The recess is filled with a potting material 9. The standard materials for the potting material 9 are known to those skilled in the art; one example is an epoxy resin. Disposed between the layer sequence 4 and the converter lamina 3 is a bonding layer 2. The bonding layer 2 comprises an inorganic-organic hybrid material having Si—O—Si, Si—O—Al and Al—O—Al bonds or Si—O—Si, Si—O—Zr and Zr—O—Zr bonds. The bonding layer can be produced as follows:

(25) A) providing a layer sequence (4) having an active layer and a converter lamina (3),

(26) B) producing an adhesive,

(27) C) applying the adhesive to the layer sequence (4) or to the converter lamina (3),

(28) D) positioning the converter lamina (3) atop the layer sequence (4) or positioning the layer sequence (4) atop the converter lamina (3),

(29) E) curing the adhesive to form the bonding layer (2),

(30) where process step B) comprises the following process steps:

(31) B1) providing a first reaction mixture comprising a first compound (formula IIIa) and a second compound (formula IIId) of the formula III:

(32) ##STR00014##

(33) where each R′ is independently selected from a group comprising hydrogen, methyl, ethyl, propyl and isopropyl radicals and combinations thereof,

(34) m=0, 1, 2, 3, 4 or 5, and

(35) n=1, 2, 3, 4 or 5,

(36) B2) adding a solution comprising a compound of the formula I and a compound of the formula II dropwise to the first reaction mixture to form a second reaction mixture

(37) ##STR00015##

(38) where, in formula I:

(39) M=Al or Zr,

(40) R is selected from a group comprising hydrogen, methyl, ethyl, propyl, isopropyl and sec-butyl radicals and combinations thereof,

(41) and x=3 when M=Al or x=4 when M=Zr;

(42) and where, in formula II:

(43) R.sup.1 is selected from a group comprising hydrogen, methyl, ethyl, propyl and isopropyl radicals and combinations thereof. R.sup.2 is selected from a group comprising methoxy, ethoxy, propoxy and isopropoxy radicals and combinations thereof.

(44) Preferably, the optoelectronic component 1 is an LED, wherein the radiation is coupled out in the upward direction through a transparent layer sequence 4, a transparent bonding layer and a transparent potting material 9.

(45) FIG. 3 shows two thermal conductivities of each of two silicon wafers bonded with a bonding layer. Each bonding layer has a thickness of 25 μm. Each composite composed of two silicon wafers and a bonding layer disposed in between has a thickness of 0.6 mm. The silicon wafers each have an area of 1 cm×1 cm. Plotted on the y axis is the thermal conductivity in W/mK, and plotted on the x axis is the temperature T in ° C. The thermal conductivity of a composite of two silicon wafers bonded with a silicone bonding layer is assigned the thermal conductivity given the reference numeral I. The thermal conductivity of a composite of two silicon wafers bonded with an inventive bonding layer is assigned the thermal conductivity given the reference numeral II. The bonding layer of the invention is produced as follows:

(46) B1) providing a first reaction mixture with 0.15 mol of glycidoxypropyltrimethoxysilane (formula IIIa″) and 0.012 mol of aminopropyltrimethoxysilane (formula IVa′)

(47) ##STR00016##

(48) B1a) cooling the first reaction mixture to a temperature between 1° C. and 15° C., leaving the first reaction mixture to stir for 20 minutes,

(49) B2) adding a solution consisting of aluminum sec-butoxide (formula Ia′) and ethyl acetoacetate (formula IIa) in a molar ratio of 5:1 to 1:1 dropwise to the first reaction mixture to form a second reaction mixture

(50) ##STR00017##

(51) stirring the second reaction mixture for 60 minutes,

(52) B3) adding HCl having a pH between 1 and 4 to the second reaction mixture to form a third reaction mixture,

(53) leaving the third reaction mixture to stir for 2 h,

(54) stirring the third reaction mixture for several hours to form the adhesive,

(55) C) applying the adhesive to a silicon wafer,

(56) D) positioning a further silicon wafer,

(57) E) curing the adhesive to form the bonding layer, comprising the process steps of:

(58) E1) preliminary curing of the adhesive at room temperature for 30 to 60 minutes,

(59) E2) thermal post-curing of the adhesive in an oven with a heating rate of 1-10 K/min up to a temperature of 130° C. for 0.5 to 2 h.

(60) It is found that the composite having the bonding layer of the invention, as compared with the composite having the silicone bonding layer, over a temperature range from 25° C. to 150° C., has 3 to 3.5 times as high a thermal conductivity. Moreover, the thermal conductivity II of the composite having the bonding layer of the invention is virtually stable over the temperature range from 25° C. to 150° C. shown.

(61) The invention is not restricted by the description with reference to the working examples. Instead, the invention encompasses every novel feature and every combination of features, which especially includes every combination of features in the claims, even if this feature or this combination itself is not explicitly specified in the claims or working examples.