Method for producing optoelectronic semiconductor components and optoelectronic semiconductor component

Abstract

A method for producing optoelectronic semiconductor components and an optoelectronic semiconductor component are disclosed. In an embodiment the method includes: A) creating a blank by pultrusion from a glass melt, B) shaping the blank into a billet-shaped optical element with a longitudinal axis, the optical element having a mounting side and a light outlet side, C) producing conductor tracks on the mounting side, D) mounting a plurality of optoelectronic semiconductor chips on the mounting side of the optical element and connecting them to the conductor tracks and E) separating the optical element into the optoelectronic semiconductor components, wherein each optoelectronic semiconductor component comprises at least two of the semiconductor chips, and wherein at least steps A) to D) are performed in the stated sequence.

Claims

1. A method for producing optoelectronic semiconductor components, the method comprising: A) creating a blank by pultrusion from a glass melt; B) shaping the blank into a billet-shaped optical element with a longitudinal axis, the optical element having a mounting side and a light outlet side; C) producing conductor tracks on the mounting side; D) mounting a plurality of optoelectronic semiconductor chips on the mounting side of the optical element and connecting them to the conductor tracks; and E) separating the optical element into the optoelectronic semiconductor components, wherein each optoelectronic semiconductor component comprises at least two of the semiconductor chips, wherein at least steps A) to D) are performed in the stated sequence, and wherein at least steps B) and C) take place during cooling at a temperature of at least 110 C.

2. The method according to claim 1, wherein the temperature is at least 140 C.

3. The method according to claim 1, wherein the blank is homogeneous with regard to its material composition after step A) such that no fluctuations in material composition occur.

4. The method according to claim 1, wherein producing the conductor tracks comprises: printing the conductor tracks on the mounting side with an ink containing silver particles; and sintering the conductor tracks using the temperature of the optical element, wherein no additional heat is introduced.

5. The method according to claim 1, further comprising applying at least one luminescent material to the mounting side at least in places between steps B) and C), wherein the luminescent material sinks at least partly into the blank.

6. The method according to claim 5, wherein applying at least one luminescent material comprises performing applying the at least one luminescent material at a temperature of between 400 C. and 600 C. inclusive.

7. The method according to claim 5, wherein the luminescent material or at least one of the luminescent materials is or comprises a nitride or an oxynitride, and wherein at least the luminescent material is present in form of particles with an average diameter of between 3 m and 25 m inclusive.

8. The method according to claim 1, wherein the mounting side is planar or has a radius of curvature of at least 25 mm.

9. The method according to claim 1, further comprising forming a plurality of blind holes in the mounting side, wherein, in step D), each semiconductor chip is introduced into one of the blind holes.

10. The method according to claim 1, wherein, in step B), the blank is shaped with structured forming rollers such that along the longitudinal axis a cross-section of the optical element, perpendicular to the longitudinal axis, varies periodically.

11. The method according to claim 10, wherein the optical element comprises respectively concavely and convexly curved regions of the light outlet side both in a cross-section parallel to the longitudinal axis and in a cross-section perpendicular to the longitudinal axis.

12. The method according to claim 1, further comprising applying a mirror layer to the mounting side at least in regions which are not covered by the semiconductor chips.

13. The method according to claim 1, wherein red-emitting semiconductor chips and blue-emitting semiconductor chips are arranged alternately along the longitudinal axis, wherein a scattering medium for light scattering is located in each case between the red-emitting semiconductor chips and the light outlet side and at least one luminescent material is located in each case between the blue-emitting semiconductor chips and the light outlet side, and wherein protective devices to protect against damage from electrostatic discharges and plug connectors for connection of the semiconductor components are mounted on the mounting side in or after step D).

14. The method according to claim 1, wherein step E) takes place directly after or in step B), and wherein end faces of the optical element are provided with a convex curvature.

15. The method according to claim 1, wherein the optical element is a mechanically load-bearing part of the semiconductor components.

16. An optoelectronic semiconductor component, wherein a semiconductor component is produced by the method according to claim 1, wherein the semiconductor component comprises at least two of the semiconductor chips, wherein the semiconductor chips are arranged along the longitudinal axis of the optical element, wherein a length and width of the optical element are equal to a length and width of the semiconductor component, when viewed in plan view onto the mounting side, wherein the length exceeds the width by at least a factor of 8, and wherein the optical element is the only mechanically load-bearing part of the semiconductor component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A method described here and an optoelectronic semiconductor component described here will be explained in greater detail below with reference to the drawings and with the aid of exemplary embodiments. Elements which are the same in the individual figures are indicated with the same reference numerals. The relationships between the elements are not shown to scale however, unless otherwise indicated, but rather individual elements may be shown exaggeratedly large to assist in understanding.

(2) In the figures:

(3) FIG. 1, which includes FIGS. 1A-1G, shows an exemplary embodiment of a production method for semiconductor components described here,

(4) FIG. 2 shows a perspective representation of an exemplary embodiment of the semiconductor component,

(5) FIG. 3, which includes Figures 3A-3B, shows sectional representations of an exemplary embodiment of the semiconductor component,

(6) FIG. 4 shows a perspective representation of a further exemplary embodiment of the semiconductor component,

(7) FIG. 5 shows a perspective representation of another exemplary embodiment of the semiconductor component,

(8) FIG. 6 shows a schematic representations of yet another exemplary embodiments of optoelectronic semiconductor component,

(9) FIG. 7 shows a schematic plan view onto an arrangement with optoelectronic semiconductor components described here, and

(10) FIG. 8, which includes FIGS. 8A-8C, shows schematic representations of optical elements for optoelectronic semiconductor components described here.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

(11) FIG. 1 shows schematic perspective representations illustrating a method for producing optoelectronic semiconductor components 1.

(12) FIGS. 1A and 1B show that a blank 21 for an optical element 2 is shaped from a melt by pultrusion. The blank 21, which for example is drawn from a melt and which is in particular formed homogeneously from a glass, is brought into the desired shape by forming rollers 26.

(13) The optical element 2 comprises a mounting side 23, which is planar or substantially planar in form. Opposite the mounting side 23 is a light outlet side 22, which is curved. Beam shaping is performed by the optical element 2 by way of the light outlet side 22. Perpendicular to a longitudinal axis A of the optical element 2 when viewed in cross-section, said element is for example semicircular in shape.

(14) It is optionally possible for the optical element 2 to be split and cut to length during shaping. In this case, end faces 28 may be purposefully provided with optically active rounding or an optically active shape.

(15) Pultrusion from the melt and shaping with the forming rollers 26, of which there are for example two, is in particular a continuous process, with which a blank and an optical element 2 may be produced with as far as possible freely selectable lengths. The step of drawing the viscous material for the blank 21 from a melt, in particular from a melter, proceeds for example at a temperature of roughly 950 C. Shaping of the blank 21 with the forming rollers 26 to yield the optical element 2 proceeds for example at a temperature of roughly 650 C. Due to use of the forming rollers 26, the optical element 2 may be produced without lateral seams and gates, unlike for example when compression molding or injection molding are used.

(16) FIG. 1C shows that after shaping the optical element 2 is diverted, cooled further and preferably conveyed on in the same production line. Transfer to another production facility is preferably not necessary.

(17) During the cooling phase of the optical element, the latter may be constantly drawn on further along a cooling section and the further process steps may be performed along this cooling section. The temperature prevailing at the respective processing site may thus be utilized. For example, according to the optional method step shown in FIG. 1D, particles of a luminescent material 5 are sprayed onto the mounting side 23 with a nozzle 50. In this process step the optical element 2 preferably has a temperature of between 500 C. and 600 C. inclusive, for example of roughly 550 C. This makes it possible for the particles of the luminescent material 5 to sink purposefully into the optical element 2.

(18) It is optionally possible for further rolling of the optical element 2 to take place, after the step in FIG. 1D, to make it easier for the particles of the luminescent material 5 to sink in or to smooth the mounting side 23. Alternatively, it is furthermore possible for the luminescent material 5 to be applied as early as in or prior to the step according to FIG. 1B.

(19) In the method step according to FIG. 1E, structured conductor tracks 4 are applied to the mounting side 23 using a printing nozzle 40. This method step preferably takes place at a temperature of roughly 150 C. In this way, sinter-bonding and/or curing of an ink for the conductor tracks 4 is possible during continued cooling of the optical element 2.

(20) In the method step according to FIG. 1F, optoelectronic semiconductor chips 3, in particular light-emitting diode chips, are applied to the mounting side 23 and to the luminescent material 5. Application of the semiconductor chips 3 proceeds for example by means of soldering or by means of electrically conductive adhesion.

(21) The semiconductor chips 3 in this case comprise a main emission direction towards the mounting side 23. Both electrical contacts of the semiconductor chips 3 are preferably located on a side of the semiconductor chips 3 facing the mounting side 23. The semiconductor chips 3 are preferably unpackaged chips. The semiconductor chips 3 may be interconnected with the conductor tracks 4 to yield one or more series circuits and/or also to yield one or more parallel circuits.

(22) As preferably also in all other exemplary embodiments, the optical element 2 comprises a comparatively long length L along the longitudinal axis A and a comparatively small width B in the direction perpendicular to the longitudinal axis A. The length L exceeds the width B for example by at least a factor of 8 or 12 or 20. It is possible for the length L to be at least 6 cm or 10 cm or 15 cm and/or at most 2 m or 60 cm or 30 cm. The width B and/or an average diameter of the optical element 2 is/are in particular at least 2 mm or 5 mm and/or at most 30 mm or 10 mm.

(23) FIG. 1G shows connection of the semiconductor component 1. Via electrical lines 44 at both end faces of the optical element 2, the semiconductor component 1 is connected to driving electronics 45, for example to an electrical ballast. The driving electronics 45 make the semiconductor component 1 electrically drivable and operable.

(24) FIG. 2 is a perspective representation of a further exemplary embodiment of the semiconductor component 1. The mounting side 23 is provided, as is also possible in all the other exemplary embodiments, with a metallic or dielectric mirror layer 6. The mirror layer 6 may completely cover the mounting side 23, with the exception of regions on which the semiconductor chips 3 are located.

(25) According to FIG. 2, the mounting side 23 is free of any luminescent material 5. Such a luminescent material may already be integrated into the semiconductor chips 3. Alternatively, it is possible for the semiconductor chips 3 to emit in three different colors. For example, red light-, green light- and blue light-emitting semiconductor chips 3 are used.

(26) FIGS. 3A and 3B show sectional representations of an exemplary embodiment of the semiconductor component 1. Between the semiconductor chips 3 and the optical element 2 is located a filling medium 29, which is formed for example from a silicone. This results in better optical coupling of the semiconductor chip 3 to the optical element 2. Such a filling medium 29 may also be present in all the other exemplary embodiments.

(27) FIG. 3B shows that the light outlet side 22 of the optical element 2 comprises a concavely curved and a convexly curved region. This enables beam expansion in a direction perpendicular to the longitudinal axis A. The progress of radiation R out of the semiconductor chip 3 is shown schematically in FIG. 3B by arrowed lines.

(28) In the exemplary embodiment of the semiconductor component 1 as shown in perspective representation in FIG. 4, the conductor tracks 4 are guided such that electrical connection is possible via a plug connector 9 on the mounting side 23 in the region of just one of the end faces 28. Such plug connectors 9 may also be present in all other exemplary embodiments. The plug connector 9 makes it possible to bring about external electrical and also mechanical fastening of the semiconductor components 1. Unlike in the representation, it is also possible for the plug connector 9 to be mounted directly on one of the end faces 28 or on both end faces 28, in order to allow a plurality of semiconductor components 1 to be plugged together along the longitudinal axis A.

(29) Furthermore, a protective device 8 is optionally additionally mounted on the mounting side 23 to protect against damage from electrostatic discharges. As an alternative or in addition to the protective device 8, other electrical components such as control chips may also be mounted. Likewise unlike in the representation, it is possible for the semiconductor chips 3 to be electrically individually drivable or to be connected into individually electrically drivable groups. In this way, a color location emitted by the semiconductor component 1 when in operation may for example be purposefully adjusted.

(30) In the exemplary embodiment according to FIG. 5, the luminescent material 5 is applied only in regions on the mounting side 23 in which the semiconductor chips 3 are located. Remaining regions of the mounting side 23 may be optionally covered with the mirror layer 6.

(31) The semiconductor component 1 as shown in FIG. 6 comprises red light-emitting semiconductor chips 3r and blue light-emitting semiconductor chips 3b. The semiconductor chips 3b, 3r are mounted alternately in the longitudinal direction A. Between the blue-emitting semiconductor chips 3b and the optical element 2 there is in each case located at least one luminescent material 5, for example YAG:Ce.

(32) Between the red-emitting semiconductor chips 3r and the optical element 2, a scattering medium 7 is applied in each case in places. Such a scattering medium 7 may also be present in all other exemplary embodiments. Unlike in the Figure, it is possible, as also in all other exemplary embodiments, for the scattering medium 7 to completely cover the mounting side 23. Alternatively or in addition, the scattering medium 7 may be applied in places or over the entire surface of the light outlet side 22, in particular for the purpose of glare suppression.

(33) FIG. 7 shows an arrangement 10 with a plurality of semiconductor components 1. To simplify the representation, conductor tracks respectively between the individual semiconductor components 1 are not shown in FIG. 7. The semiconductor components 1 are mounted on a common carrier 11. Also optionally located on the carrier 11 is the driving electronics 45. The arrangement 10 is, for example, a replacement for a fluorescent tube. The spatial dimensions of the arrangement 10 are however preferably smaller than the dimensions of a conventional fluorescent tube, in particular in a direction perpendicular to longitudinal axis A.

(34) FIGS. 8A to 8C are sectional representations and plan views of exemplary embodiments of the optical element 2. The optical elements 2 each comprise concavely and convexly curved regions along cross-sections perpendicular to the longitudinal direction A and also parallel to the longitudinal direction A, said regions alternating in particular periodically along the longitudinal direction.

(35) The left-hand parts of FIGS. 8A to 8C in each case show a sectional representation perpendicular to the longitudinal axis A. The representations at the top right in FIGS. 8A to 8C are sectional representations along the longitudinal axis A. At bottom right FIGS. 8A and 8B represent plan views of the optical elements 2 and FIG. 8C represents views from below.

(36) FIGS. 8A and 8B show that the optical element 2, when viewed in plan view onto the light outlet side 22, in each case comprises peaks and troughs. An indentation is preferably formed in the peak portions, which is surrounded by embankments formed of a material of the optical element 2.

(37) Blind holes 25 may be formed in the mounting sides 23, see FIG. 8C. The blind holes 25 are configured to receive the semiconductor chips, not shown in FIGS. 8A to 8C. Preferably precisely one blind hole 25 for one of the semiconductor chips is provided per periodic length of the optical element 2 along the longitudinal axis A. Such blind holes 25 may also be present in all other exemplary embodiments.

(38) In the sectional representations perpendicular to the longitudinal axis A in FIGS. 8A to 8C, possible dimensions for the optical element 2 are indicated in each case by way of example. The representations in FIGS. 8A to 8C should be understood in this respect as being to scale. The stated dimensions apply for example in each case with a tolerance of at most a factor of 3 or 2 or 1.5 or 1.25. The dimensional ratios relative to one another in each case preferably apply with a tolerance of at most a factor of 2 or 1.5 or 1.15.

(39) The following advantages are achieved in particular by a production method described here and by the semiconductor components 1 described here:

(40) In various embodiments no printed circuit board, or PCB, is needed to interconnect the semiconductor chips.

(41) In various other embodiments production proceeds with only little processing effort and is flexibly configurable, in particular optical elements of different lengths can be produced without major changes to the process.

(42) The entire process can be performed during the cooling phase and glass rod production for the optical element, i.e. an on the fly process can be achieved.

(43) In various embodiments the production sites have only a small space requirement and no additional transport effort has to be undertaken between production processes.

(44) In yet other embodiments different geometries of the optical element 2 can be simply produced using different forming rollers. This allows different emission patterns of the semiconductor components 1 to be simply produced and adjusted for different applications.

(45) In some embodiments the dimensions of the semiconductor components described here are significantly smaller than the dimensions of conventional systems, in particular smaller than the dimensions of normal fluorescent tubes.

(46) The invention described here is not restricted by the description given with reference to the exemplary embodiments. Rather, the invention encompasses any novel feature and any combination of features, including in particular any combination of features in the claims, even if this feature or this combination is not itself explicitly indicated in the claims or exemplary embodiments.