Housing for an optoelectronic device, and method for producing same, and lid for a housing

Abstract

The invention relates to a housing for an optoelectronic device and to a method for producing such a housing. For producing a lid for the housing, an infrared-transparent material is used, into which at least one glass window is integrated.

Claims

1. A housing for at least one electronic device, the housing including a base part, wherein the base part includes a first mounting area for the at least one electronic device, the housing further including a lid made of a material that is transparent to infrared radiation, wherein the lid made of material that is transparent to infrared radiation has at least one glass window integrated therein, wherein the lid is connected to the base part so as to hermetically seal the housing, wherein the material that is transparent to infrared radiation has an average transmittance of more than 40% across an entire wavelength range between 1.5 μm to 5 μm.

2. The housing as claimed in claim 1, wherein the at least one glass window is transparent to at least one of UV radiation and visible light.

3. The housing as claimed in claim 1, wherein the lid made of an infrared radiation transparent material is made of silicon, aluminum oxide, in particular sapphire, or germanium.

4. The housing as claimed in claim 1, wherein the at least one glass window is made of a glass having a coefficient of mean linear thermal expansion (α) at 20 to 300° C. of 2 to 5 ppm/K.

5. The housing as claimed in claim 1, wherein the at least one glass window, at 20° C., is under a stress ranging between −100 MPa of compressive stress and +30 MPa of tensile stress.

6. The housing as claimed in claim 1, wherein the at least one glass window is made of a glass having a coefficient of mean linear thermal expansion (α) at 20 to 300° C. of 3 to 5 ppm/K and a glass transition temperature (Tg) between 300 and 600° C.

7. The housing as claimed in claim 1, wherein the at least one glass window has been integrated into the lid by fusing.

8. The housing as claimed in claim 1, wherein the first mounting area is arranged under a portion of the lid made of material that is transparent to infrared radiation and the housing further includes a second mounting area arranged under the at least one glass window.

9. The housing as claimed in claim 1, wherein the at least one glass window is made of borosilicate glass.

10. A housing for at least one electronic device, the housing including a base part, wherein the base part includes a mounting area for the at least one electronic device, the housing further including a lid made of a material that is transparent to infrared radiation, wherein the lid made of material that is transparent to infrared radiation has at least one glass window integrated therein, wherein the lid is connected to the base part so as to hermetically seal the housing, wherein the lid is made of an infrared radiation transparent material selected from a group consisting of silicon, aluminum oxide, sapphire, germanium, and mixtures thereof, wherein the at least one glass window is transparent to at least one of UV radiation or visible light.

11. A housing for at least one electronic device, the housing including a base part, wherein the base part includes a mounting area for the at least one electronic device, the housing further including a lid, wherein the lid has a plurality of windows integrated therein that are made of a material transparent to a first range of wavelengths of light and the lid is transparent to a second range of wavelengths of light that differs from the first range of wavelengths of light, wherein the lid is connected to the base part so as to hermetically seal the housing, wherein the lid is made of an infrared radiation transparent material selected from a group consisting of silicon, aluminum oxide, sapphire, germanium, and mixtures thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of (an) embodiment(s) of the invention taken in conjunction with the accompanying drawing(s), wherein:

(2) FIGS. 1a and 1b are schematic sectional views intended to explain the configuration of a generic housing for optoelectronic devices as it is known from prior art.

(3) FIGS. 2a to 2d are intended to illustrate an exemplary embodiment of a method according to the invention in which the glass windows are integrated into the lid by fusing.

(4) FIGS. 3a to 3d show an exemplary embodiment in which the glass windows are connected to the lid substrate by means of a solder.

(5) FIGS. 4a to 4d show a method in which a structured glass wafer is applied to the substrate and connected thereto by welding or anionic bonding.

(6) FIGS. 5a and 5b are schematic sectional views of the components of an exemplary embodiment of a housing according to the invention including optoelectronic devices.

(7) FIGS. 6a and 6b show further schematic sectional views of an alternative embodiment of a housing including optoelectronic devices.

(8) FIGS. 7a to 7c are schematic sectional views intended to illustrate how a plurality of optoelectronic devices provided in a wafer assembly are equipped with a lid and are subsequently diced.

(9) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

(10) FIGS. 1a and 1b show, by way of a sectional view, how a housing 11 for optoelectronic devices 16a, 16b is produced according to the prior art.

(11) As illustrated in the sectional view of FIG. 1a, housing 11 consists of a lower part 12, onto which at least one lid 1 is applied.

(12) The lower part 12 has recesses, each one defining a mounting area 15a, 15b for an optoelectronic device 16a, 16b.

(13) In order to close the mounting areas 15a, 15b with a hermetically sealed lid 1, two windows 14a, 14b are applied directly onto the lower part 12 which forms a frame for the windows 14a and 14b. Thus, the lid 1 is formed by windows 14a and 14b.

(14) As shown in FIG. 1b, windows 14a, 14b are connected to the lower part 12 by attaching them to the lower part 12 in hermetically sealing manner by means of a solder, for example.

(15) Window 14a may, for example, be transparent to infrared radiation so that, accordingly, the optoelectronic device 16a is for instance an infrared sensor. Window 14b, by contrast, may be transparent to ultra violet (“UV”) radiation or visible light, for example, so that the optoelectronic device 16b is for instance implemented as an light-emitting diode (“LED”) or a photocell.

(16) The attachment of the windows 14a and 14b is complicated because they have to be applied, as individual windows, on a frame which is provided as part of the lower part 12 of the housing 11 in this embodiment.

(17) The invention therefore proposes to provide a single lid in which the material of the lid itself provides the window that is transparent to infrared radiation, and the lid has a glass window which is transparent in another wavelength range.

(18) FIGS. 2a to 2d show the method steps for integrating the glass windows into such a lid 1 according to the first embodiment of the invention.

(19) For providing a lid 1, first a substrate 2 is provided, in particular in the form of a silicon wafer, (see FIG. 2 a).

(20) Then, as shown in FIG. 2b, openings 3 are introduced into the substrate 2, for example by etching or mechanical processing.

(21) Then, as shown in FIG. 2c, glass inserts 4a, 4b are introduced into the openings 3.

(22) As illustrated in FIG. 2d, the lid 1 is then heated to a temperature above the glass transition temperature T.sub.g.

(23) The glass of the glass inserts 4a and 4b softens and bonds to the lateral surface of the opening 3 of the substrate 2 to form a hermetic seal. In this way, windows 5a, 5b are being formed from the fused glass inserts 4a, 4b.

(24) Depending on the glass that is used, its volume and its surface tension, and depending on the atmosphere under which the heating is performed, a lens may form, as illustrated by window 5b.

(25) Now, an IR-transparent window exists below an area 6 of the lid 1, which window is defined by the lid 1. In the area 7, by contrast, a window 5a is provided which is transparent to UV and/or to visible light.

(26) Thus, mounting areas for different optoelectronic devices can be arranged below areas 6 and 7.

(27) Once the glass windows 5a, 5b have been introduced, lid 1 is preferably connected to a base part 12, as illustrated in FIGS. 5a and 6a in particular to a wafer on which the electronic devices are arranged.

(28) Then the wafer is ready to be diced into individual dies.

(29) According to one embodiment of the invention it is suggested that the dicing, that is to say the separating of the wafer, is effected in a portion of the lid 1.

(30) It is in particular also suggested according to the invention that diced components are provided which do not have a glass window, but only a lid that is transparent to infrared radiation.

(31) In the wafer assembly, the invention offers significant cost advantages also for such embodiments.

(32) Referring to FIGS. 3a to 3d, a further embodiment of the method according to the invention will be explained.

(33) As illustrated in FIGS. 3a and 3b, first, openings 3 are introduced into the substrate 2 of the lid 1, like in the method described above with reference to FIGS. 2a to 2d.

(34) Then, as shown in FIG. 3c and in contrast to the method described with reference to FIGS. 2a to 2d, glass windows 5a, 5b are provided which are not connected to the substrate 2 by softening the glass of the glass windows 5a, 5b itself, but rather by using a solder, in particular a solder glass 10a, 10b.

(35) Windows 5a, 5b may be plate-shaped windows, or else optical components, for example in the form of a lens, as symbolized by the round shape of glass window 5b.

(36) By heating the glass solder 10a, 10b, glass windows 5a, 5b are bonded to the substrate 2, and in the present embodiment, the windows 5a, 5b protrude from the substrate and the glass solder 10a, 10b is disposed around the protruding portion.

(37) According to a further embodiment of the invention, it is likewise possible for the glass solder 10a, 10b, for example, to be introduced into the opening 3 in the form of a sleeve so as to connect the lateral surfaces of the glass windows 5a, 5a to the lateral surfaces of the opening 3 (not shown).

(38) FIGS. 4a to 4b schematically show a further embodiment of the invention, in which a substrate 2 is provided, in particular in the form of a silicon wafer, into which, again, openings 3 are introduced.

(39) Furthermore, a glass substrate 8 is provided, in particular a glass wafer, which is structured as illustrated in FIG. 4b, thereby producing open areas 9 and closed areas forming the later glass windows 5a, 5b.

(40) As illustrated in FIG. 4c, the glass substrate 8 is placed onto the substrate 2 of the lid 1 such that the glass windows 5a, 5b cover the openings 3.

(41) Then, glass windows 5a, 5b are connected to the substrate 2.

(42) This can be done by welding, in particular using laser radiation. In particular, the glass substrate 8 and the substrate 2 of the lid may be pressed together, and a focused laser may be used to heat the material of both the substrate 2 and the glass window 5 at the edges of openings 3 so that welding occurs.

(43) According to a further embodiment, the connecting step illustrated in FIG. 4d may be effected by anionic bonding. In this case, a voltage is applied between the two halves of a tool which clamps the assembly consisting of glass substrate 8 and substrate 2 of the lid, at a high temperature, typically above 350° C. In particular an alkali-containing glass can be used in this case. Due to charge zones because of ion migration at the interfaces, silicon oxygen bridges are being formed which result in a bond between glass substrate 8 and substrate 2.

(44) As in the other embodiments, a portion of the substrate 2 of lid 1 itself provides an area 6 that is transparent to infrared radiation, whereas a glass window 5a defines a mounting area over which the lid 1 is transparent in another wavelength range.

(45) Referring to the schematic sectional views of FIGS. 5a and 5b, it will be explained how a housing 11 with a lid 1 according to the invention is formed.

(46) As shown in FIG. 5a, the housing 11 consists of a base part or lower part 12 and the lid 1 in this embodiment.

(47) Lid 1 preferably has a plate-like shape and comprises a substrate made of a material that is transparent to infrared radiation, as described above.

(48) Furthermore, lid 1 comprises a window 5a preferably integrated by fusing, which is transparent in another range of wavelengths.

(49) The lower part 12 has recesses 15a, 15b in this embodiment, each of which defines a mounting area 13a, 13b for at least one optoelectronic device 16a, 16b.

(50) The lower part 12 may comprise feedthroughs and/or circuit traces (not shown) for the optoelectronic devices 16a, 16b.

(51) The lower part 12 may be made of silicon or ceramics, for example.

(52) In this exemplary embodiment, the lower part 12 has at least one web 17 separating the mounting areas 13a and 13b from each other.

(53) Web 17 also serves as a support surface for the lid 1.

(54) Mounting areas 13a, 13b preferably have an surface area from 4 mm.sup.2 to 10 cm.sup.2, in plan view.

(55) As illustrated in FIG. 5b, lid 1 is connected to the base part 12 so as to form a hermetically sealed mounting area 13a, 13b.

(56) This can be achieved by using a glass solder or metal solder, for example.

(57) Window 5a is preferably integrated into the substrate of lid 1 before lid 1 is connected to the lower part 12.

(58) The material of the lid 1 itself is transparent to infrared radiation, so that the area 6 provides a window for entry or exit of infrared radiation for the optoelectronic device 16a.

(59) Window 5a, by contrast, provides an area 7 which defines a window for UV radiation or visible light, for example. Accordingly, the optoelectronic device 16b will either receive and/or emit UV radiation and/or radiation in the visible wavelength range.

(60) FIGS. 6a and 6b show an alternative embodiment of the invention, in which in contrast to the embodiment according to FIGS. 5a and 5b, the window 5b which provides an area 7 that is transparent to UV radiation or visible light, has the form of a lens.

(61) Such a window 5b in the form of a lens may be provided, as already described with reference to FIGS. 2a to 2d, by integrating a glass insert by fusing, which forms a lens due to its surface tension.

(62) Referring to FIGS. 7a to 7c, the manufacturing of a plurality of housings 11 will be described, which is achieved in a wafer assembly according to an embodiment of the invention.

(63) As illustrated in FIG. 7a, a wafer 18 is used for this purpose, in particular a silicon wafer or a ceramic wafer having a multiplicity of recesses each one defining a mounting area, 13a and 13b, respectively.

(64) Prior to the application of lid 1, an optoelectronic device 16a, 16b is introduced into each of these recesses and is electrically connected, for example, via feedthroughs of the wafer 18 (not shown herein).

(65) Lid 1 has a plurality of windows 5a which are transparent to a different range of wavelengths than the material of the lid 1 itself, as already mentioned above.

(66) Lid 1 has a size large enough to cover the surface area of a plurality of housings 11. Preferably, a single lid 1 is used for a single wafer 18.

(67) As illustrated in FIG. 7b, the wafer 18 which simultaneously forms the lower part of housing 11, is connected to the lid 1.

(68) Then, the wafer 18 is diced into a plurality of housings 11 by being cut along the walls 19, as shown in FIG. 7c.

(69) Then, in this embodiment, each housing 11 has a lid 1 which includes an area 6 that is transparent to infrared radiation, and a further area 7 that is formed by the window 5a and is transparent to a different wavelength.

(70) Due to the fabrication in the wafer assembly, as intended according to one embodiment of the invention, it is possible to provide, in a simple manner, housings with optoelectronic devices, which include a mounting area for a UV-selective optoelectronic device and/or for an optoelectronic device selective in another wavelength range.

(71) According to a further, second embodiment of the invention, the lid 1 consists of glass, and the window 5a/5b is made of a material that is transparent to infrared radiation. Otherwise, with the exception of the design of the windows in the form of fused lenses, the housing 11, in particular the lid 1, can be formed and/or manufactured as described above.

(72) In this embodiment of the invention, the lid 1 preferably consists of a borosilicate glass and is connected to the base part/lower part 12 and to the window 5a/5b by anionic bonding.

(73) The invention furthermore permits to provide, in simplified manner, a hermetically sealed housing having both an area that is transparent to infrared radiation and a glass window which transmits electromagnetic radiation in a different wavelength range.

(74) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

LIST OF REFERENCE NUMERALS

(75) 1 Lid 2 Substrate 3 Opening 4a, 4b Glass insert 5a, 5b Window 6 Window transparent to infrared radiation 7 Windows for UV radiation and/or visible light 8 Glass substrate 9 Open area 10a, 10b Solder glass 11 Housing 12 Base part/lower part 13a, 13b Mounting area 14a, 14b Windows 15a, 15b Recess 16a, 16b Optoelectronic device 17 Web 18 Wafer 19 Wall