JP2009206217A - Manufacturing method of light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a light emitting device that can efficiently converges part of light emitted from a light emitting element on an optical detecting element and also has a higher manufacturing yield. <P>SOLUTION: After a through-hole 32 is formed on a silicon substrate 30a for forming a substrate 30 for light distribution, an insulating film (silicon oxide film) 33 is formed, a recess 31a is formed through anisotropic etching using an alkali-based solution, and a silicon oxide film 33b is formed on an inner surface and an inner bottom surface of the recess 31a. Through hole wiring 34 is formed and a mirror film 39 is formed on the silicon oxide film 33b; and a conductor pattern (second metal layer for connection) 35 is formed on the other surface side of the silicon substrate 30a, and a metal layer 37a on which a conductor pattern (first metal layer for connection) 37 is based is formed on one surface side. The other surface side of the silicon substrate 30a other than a part corresponding to an opening window 31 is covered with a resist mask 135, and etching is carried out from the other surface side to form an opening window 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light emitting device using a light emitting element such as a light emitting diode chip (LED chip).

  Conventionally, as shown in FIG. 12, a light-emitting element 1 made of an LED chip and a storage recess 2a that is formed using three silicon substrates 20a, 30a, and 40a and stores the light-emitting element 1 are formed on one surface. And a photodetecting element 4 made of a photodiode for detecting light emitted from the light emitting element 1 is provided on a projecting portion 2c projecting inwardly from the peripheral portion of the housing recess 2a. A formed light emitting device has been proposed (see Patent Document 1).

  Here, the mounting substrate 2 described above is formed using the silicon substrate 20a, the base substrate 20 on which the light emitting element 1 is mounted on one surface side, and the one surface side of the base substrate 20 formed using the silicon substrate 40a. Between the base substrate 20 and the photodetecting element forming substrate 40 formed by using the silicon substrate 30a and the photodetecting element forming substrate 40 on which the photoextracting window 41 and the photodetecting element 4 are formed. An aperture window 31 that is interposed therebetween and communicates with the light extraction window 41 is formed, and the inner surface of the aperture window 31 serves as a mirror surface 2 d that guides a part of the light emitted from the light emitting element 1 to the light detection element 4. The through-hole wirings 24 and 34 that are electrically connected to the photodetecting element 4 are formed in the base substrate 20 and the light distribution substrate 30, respectively. Element 1 and electrically connected to the through-hole wiring (not shown) is formed.

  Further, the light distribution substrate 30 has a conductor pattern (hereinafter referred to as a first connection metal layer) 37 electrically connected to the through-hole wiring 34 on one surface side which is the light detection element formation substrate 40 side. A conductor pattern (hereinafter referred to as a second connection metal layer) 35 electrically connected to the through-hole wiring 34 is formed on the other surface side that is the base substrate 20 side. The connecting metal layer 37 is joined and electrically connected to a conductor pattern (hereinafter referred to as a third connecting metal layer) 47 electrically connected to the light detecting element 4 in the light detecting element forming substrate 40. The second connection metal layer 35 is joined and electrically connected to a conductor pattern (hereinafter referred to as a fourth connection metal layer) 25b electrically connected to the through-hole wiring 24 in the base substrate 20. ing. In addition, the light distribution substrate 30 and the light detection element formation substrate 40 are bonded together with bonding metal layers (not shown), and the light distribution substrate 30 and the base substrate 20 are bonded together with bonding metal layers 36 and 29. Has been.

Further, in the above-mentioned Patent Document 1, in the manufacture of the light emitting device described above, after performing a first bonding step of bonding the silicon substrate 40a on which the light detection element 4 is formed and the light distribution substrate 30, a silicon substrate is formed. A polishing process for polishing 40a to a desired thickness is performed, followed by a light extraction window forming process for forming a light extraction window 41 on the silicon substrate 40a, and then the base substrate 20 on which the light emitting element 1 is mounted and the light distribution. The second bonding step for bonding the substrate 30 to each other, and in the first bonding step and the second bonding step, the bonding surfaces are brought into contact with each other after the bonding surfaces are activated before bonding. And normal temperature bonding.
JP 2007-294834 A

  By the way, in the manufacture of the light emitting device described above, in forming the light distribution substrate 30, after the through holes 32 for the through hole wirings 34 are formed in the silicon substrate 30a by the dry etching technique, the insulating film 33 made of a silicon oxide film is formed. Then, after forming the through-hole wiring 34 using an electroplating method, after forming each connection metal layer 37, 35, a metal mask is formed and an alkaline solution (TMAH aqueous solution, KOH aqueous solution) is formed. Etc.), the mirror surface 2d is formed by forming the opening window 31 by anisotropic etching, and then the metal mask is removed by etching. Then, the bonding surfaces of the connecting metal layers 37, 35, etc. As a result, the yield of room-temperature bonding decreases, resulting in a decrease in manufacturing yield. Although a resist mask may be used instead of the metal mask, since the etching time for anisotropic etching using an alkaline solution is long (for example, 6 to 7 hours), the resistance as a mask is poor. This is sufficient, and the connecting metal layers 37 and 35 are eroded.

  In addition, the step of forming the opening window 31 in the silicon substrate 30a may be performed by dry etching using a fluorine-based gas. However, since unevenness called “scallop” is generated on the inner surface of the opening window 31, a mirror is formed. The surface roughness of the surface 2d increases, the light condensing efficiency to the light detection element 4 by the mirror surface 2d decreases, and the S / N ratio of the output of the light detection element 4 decreases. Here, it is conceivable to form a mirror film made of a material (for example, Al) having a high reflectance with respect to the light from the light emitting element 1 on the inner surface of the opening window 31 of the silicon substrate 30a. The surface roughness of the mirror film increases due to the surface roughness of the inner surface of the opening window 31.

  Further, in forming the light distribution substrate 30, if the through hole 32 and the opening window 31 for the through hole wiring 34 are formed in the silicon substrate 30a, the inner surface of the through hole 32 having an inner diameter of several tens of μm is formed by electroplating. It was difficult to form the through-hole wiring 34.

  The present invention has been made in view of the above-described reasons, and an object thereof is light emission capable of efficiently condensing a part of the light emitted from the light emitting element to the light detecting element and improving the production yield. It is to provide a method for manufacturing an apparatus.

  The invention according to claim 1 includes a light emitting element and a package formed of a mounting substrate in which at least a storage recess for storing the light emitting element is formed on one surface, and the mounting substrate is inward from a peripheral portion of the storage recess. And a light detection element for detecting the light emitted from the light emitting element. The mounting substrate is a base on which the light emitting element is mounted on one surface side. A substrate, a photodetection element forming substrate on which the light extraction window is formed while being opposed to the one surface side of the base substrate and a photodetection element is formed, and a base substrate and a photodetection formed by using a silicon substrate An opening window that is interposed between the element formation substrate and communicates with the light extraction window is formed, and a mirror film that reflects a part of the light emitted from the light emitting element to the light detection element side is formed on the inner surface of the opening window. Consists of a light distribution board and light distribution The substrate has a through-hole wiring formed thereon, a first connection metal layer electrically connected to the through-hole wiring is formed on one surface side which is the photodetecting element forming substrate side, and the base substrate side A second connection metal layer electrically connected to the through-hole wiring is formed on the other surface side, and the first connection metal layer is electrically connected to the light detection element in the light detection element formation substrate. The third connecting metal layer is joined and electrically connected, and the second connecting metal layer is joined and electrically connected to the fourth connecting metal layer formed on the base substrate. In the method of manufacturing a light emitting device, the through hole wiring is formed in the silicon substrate when forming the light distribution substrate before the bonding step of bonding the light distribution substrate and the base substrate on which the light emitting element is mounted. After forming the hole, apply a silicon oxide film on the inner surface of the through hole. A recess corresponding to a mirror surface on the inner surface is formed by anisotropically etching a portion corresponding to the opening window from one surface side with an alkaline solution, and then a silicon oxide film is formed on the inner surface and the inner bottom surface of the recess. A through-hole wiring forming process for forming a through-hole wiring inside the through-hole of the silicon substrate by using an electroplating method, and a through-hole wiring forming process after the previous-stage process A mirror film forming step of forming a mirror film on the silicon oxide film on the inner side surface of the recess of the silicon substrate, and forming a first connecting metal layer on the one surface side of the silicon substrate after the mirror film forming step And a metal layer forming step of forming a second connecting metal layer on the other surface side, and a portion other than the portion corresponding to the opening window on the other surface side of the silicon substrate after the metal layer forming step is covered with a resist mask. Then, an etching process for forming the opening window is performed by etching the portion corresponding to the opening window so as to reach the recess from the other surface side, and the resist mask is formed after the etching process for completing the opening window. And a mask removing process to be removed.

  According to the present invention, a through-hole for through-hole wiring is formed in a silicon substrate, a silicon oxide film is formed on the inner surface of the through-hole, and a portion corresponding to the opening window is anisotropically formed from one surface side with an alkaline solution. By forming a recess whose inner surface becomes a mirror surface by reactive etching and then performing a pre-process to form a silicon oxide film on the inner surface and the inner bottom surface of the recess, the inner surface is reduced by a mirror surface with a small surface roughness. In the previous step, since the recess is formed without forming an opening window penetrating in the thickness direction of the silicon substrate, in the through hole wiring forming step Through-hole wiring can be formed using electroplating, and since the silicon oxide film is formed on the inner surface and inner bottom surface of the recess before the through-hole wiring forming step, the through-hole wiring Formation process In this case, it is possible to prevent the plating precipitation portion from being formed on the inner surface of the recess and increase the surface roughness of the inner surface of the recess, and the inner surface of the recess after the through-hole wiring forming process in the mirror film forming process. Since the mirror film is formed on the silicon oxide film on the side surface, the surface roughness of the mirror film can be reduced, and the first connection metal layer and the second connection metal layer after the mirror film formation step. A metal layer forming step is performed, and then a portion other than the portion corresponding to the opening window on the other surface side of the silicon substrate is covered with a resist mask, and then the portion corresponding to the opening window is changed from the other surface side to the recess. Since the etching process is performed to complete the opening window to form the opening window by etching, and then the mask removal process to remove the resist mask is performed, the surface of the mirror film and each connection metal layer is roughened. As a result, it is possible to provide a light emitting device capable of efficiently condensing a part of the light emitted from the light emitting element onto the light detecting element and improving the manufacturing yield. it can.

  According to a second aspect of the present invention, in the first aspect of the invention, in the metal layer forming step, a metal layer serving as a basis of the first connection metal layer is formed on the one surface side of the silicon substrate. In the etching process for completing the opening window, the stacked film of the silicon oxide film and the metal layer formed on the inner bottom surface of the recess is used as an etching stopper layer. The silicon substrate is dry-etched from the other surface side to a depth reaching the laminated film, and then the silicon oxide film at a portion facing the opening window is removed by etching, and then the metal layer is patterned by wet etching. Thus, the first connecting metal layer is formed and the opening window is formed.

  According to the present invention, in the etching process for completing the opening window, the silicon substrate is used as an etching stopper layer by using the stacked film of the silicon oxide film and the metal layer formed on the inner bottom surface of the recess. The first connecting metal layer is formed by performing dry etching from the front surface side, and thereafter etching away the silicon oxide film at a portion facing the opening window, and then patterning the metal layer by wet etching. In addition, since the opening window is formed, the surface of the mirror film is prevented from being roughened in the etching process for completing the opening window as compared with the case where the silicon substrate is dry-etched from the other surface side without an etching stopper layer. In addition, etching can be performed when dry etching the silicon substrate from the other surface side. As compared with the case of utilizing a single layer film of a silicon oxide film as a stopper layer, it is possible to prevent the etching stopper layer may be broken by the pressure differential across the thickness direction of the etching stopper layer.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or claim 2, in the joining step, the joining surfaces are activated before joining, and the joining surfaces are brought into contact with each other to perform room temperature joining. To do.

  According to the present invention, in the bonding step of bonding the light distribution substrate and the base substrate on which the light emitting element is mounted, the bonding surfaces are brought into contact with each other after the bonding surfaces are activated before bonding. Since it joins, it can prevent that the characteristic of the said light emitting element deteriorates in the said joining process.

  According to the first aspect of the present invention, there is an effect that it is possible to provide a light emitting device capable of efficiently condensing a part of the light emitted from the light emitting element onto the light detecting element and improving the manufacturing yield.

  Hereinafter, after describing the light-emitting device of this embodiment based on FIGS. 3 to 11, the manufacturing method will be described based on FIGS. 1 and 2.

  As shown in FIG. 3, the light-emitting device of this embodiment includes a light-emitting element 1 made of an LED chip and a storage recess 2a for storing the light-emitting element 1, formed on one surface, and a light-emitting element on the inner bottom surface of the storage recess 2a. 1 is mounted, a translucent member 3 fixed to the mounting substrate 2 so as to close the housing recess 2a on the one surface side of the mounting substrate 2, and a light emitting element provided on the mounting substrate 2 1 from a light detecting element 4 for detecting light emitted from 1 and a translucent material (for example, silicone resin, acrylic resin, epoxy resin, polycarbonate resin, glass, etc.) filled in the housing recess 2a of the mounting substrate 2 The light emitting element 1 and the sealing part 5 which sealed the bonding wire 14 (refer FIG. 4) connected to the said light emitting element 1 are provided. Here, the mounting substrate 2 has a hook-like protrusion 2c protruding inward from the peripheral portion of the housing recess 2a on the one surface side, and the light detection element 4 is provided on the protrusion 2c. ing. In the present embodiment, the package is constituted by the mounting substrate 2 and the translucent member 3, but the translucent member 3 is not necessarily provided, and may be appropriately provided as necessary.

  As shown in FIGS. 3 to 5, the mounting substrate 2 has a rectangular plate-like base substrate 20 on which the light emitting element 1 is mounted on one surface side, and a circular shape that is disposed to face the one surface side of the base substrate 20. A light detection element forming substrate 40 on which the light extraction window 41 is formed and the light detection element 4 is formed, and a rectangular shape that is interposed between the base substrate 20 and the light detection element formation substrate 40 and communicates with the light extraction window 41. And a space surrounded by the base substrate 20, the light distribution substrate 30, and the light detection element formation substrate 40 constitutes the housing recess 2a. is doing. Here, the outer peripheral shapes of the base substrate 20, the light distribution substrate 30, and the light detection element formation substrate 40 are rectangular, and the light distribution substrate 30 and the light detection element formation substrate 40 are formed to have the same outer dimensions as the base substrate 20. Has been. Further, the thickness dimension of the light detection element forming substrate 40 is set smaller than the thickness dimension of the base substrate 20 and the light distribution substrate 30. In the present embodiment, the portion of the light detection element forming substrate 40 that protrudes above the opening window 31 of the light distribution substrate 30 constitutes the protruding portion 2c described above.

  The base substrate 20, the light distribution substrate 30, and the light detection element formation substrate 40 described above are formed using silicon substrates 20a, 30a, and 40a each having an n-type conductivity and a (100) plane main surface. The inner side surface of the opening window 31 of the light distribution substrate 30 is constituted by a mirror surface having a (111) surface formed by anisotropic etching using an alkaline solution (for example, TMAH solution, KOH solution, etc.). (That is, in the light distribution substrate 30, the opening area of the opening window 31 gradually increases with distance from the base substrate 20), and a silicon oxide film 33 b is laminated on the inner surface of the opening window 31, and the silicon A mirror film 39 that reflects part of the light emitted from the light emitting element 1 toward the light detecting element 4 is laminated on the oxide film 33b. Here, the mirror film 39 includes a reflective film made of a material (for example, Al) having a high reflectance with respect to light emitted from the light emitting element 1 and a protective film made of a silicon oxide film stacked on the reflective film. It is configured.

  As shown in FIGS. 6 and 7, the base substrate 20 includes two electrodes electrically connected to both electrodes of the light-emitting element 1 on one surface side (the left surface side in FIG. 6C) of the silicon substrate 20 a. Conductor patterns 25 a and 25 a are formed, and two conductor patterns 25 b electrically connected to the light detection element 4 through two through-hole wirings 34 and 34 described later formed on the light distribution substrate 30. 25b is formed, and the four external connection electrodes 27a, 27a, 27b formed on each conductor pattern 25a, 25a, 25b, 25b and the other surface side of the silicon substrate 20a (the right side in FIG. 6C). 27b are electrically connected to each other through the through-hole wiring 24. The base substrate 20 is also formed with a bonding metal layer 29 for bonding to the light distribution substrate 30 on the one surface side of the silicon substrate 20a.

  The light-emitting element 1 in this embodiment is a visible light LED chip in which a conductive substrate is used as a crystal growth substrate and electrodes (not shown) are formed on both surfaces in the thickness direction. Therefore, the base substrate 20 has one of the two conductor patterns 25a and 25a to which the light emitting element 1 is electrically connected, a rectangular die pad portion 25aa to which the light emitting element 1 is die-bonded, and The lead-out wiring part 25ab is formed integrally with the die pad part 25aa and is a connection part with the through-hole wiring 24. In short, the light emitting element 1 is die-bonded to the die pad portion 25aa of the one conductor pattern 25a, the electrode on the die pad portion 25aa side is joined and electrically connected to the die pad portion 25aa, and the electrode on the light extraction surface side. Is electrically connected to the other conductor pattern 25 a via the bonding wire 14.

  The base substrate 20 has a rectangular heat radiation pad portion 28 made of a metal material having a higher thermal conductivity than the silicon substrate 20a on the other surface side of the silicon substrate 20a. The pad portion 28 is thermally coupled to a plurality of (in this embodiment, nine) cylindrical thermal vias 26 made of a metal material (for example, Cu) having a higher thermal conductivity than the silicon substrate 20a. The heat generated in the light emitting element 1 is dissipated through the thermal vias 26 and the heat dissipating pads 28.

  By the way, the base substrate 20 is formed on the silicon substrate 20a with four through-holes 22a in which the above-described four through-hole wirings 24 are formed inside and nine above-mentioned nine thermal vias 26 in the inside. A through hole 22b is provided in the thickness direction, and an insulating film 23 made of a thermal oxide film (silicon oxide film) is formed across the one surface and the other surface of the silicon substrate 20a and the inner surfaces of the through holes 22a and 22b. The conductive patterns 25a, 25a, 25b, 25b, the bonding metal layer 29, the external connection electrodes 27a, 27a, 27b, 27b, the heat radiation pad 28, the through-hole wirings 24, and the thermal vias are formed. 26 is electrically insulated from the silicon substrate 20a.

  Here, each conductor pattern 25a, 25a, 25b, 25b, bonding metal layer 29, each external connection electrode 27a, 27a, 27b, 27b, and heat radiation pad portion 28 are formed on the insulating film 23. And the Au film formed on the Ti film, the conductor patterns 25a, 25a, 25b, 25b on the one surface side of the silicon substrate 20a and the bonding metal layer 29 are simultaneously formed. The external connection electrodes 27a, 27a, 27b, 27b on the other surface side of the silicon substrate 20a and the heat dissipation pad portion 28 are formed at the same time. In this embodiment, the thickness of the Ti film on the insulating film 23 is set to 15 to 50 nm, and the thickness of the Au film on the Ti film is set to 500 nm. However, these numerical values are only examples and are particularly limited. Not what you want. Further, the material of each Au film is not limited to pure gold, and may be one added with impurities. In addition, although a Ti film is interposed as an adhesion layer for improving adhesion between each Au film and the insulating film 23, the material of the adhesion layer is not limited to Ti, for example, Cr, Nb, Zr, TiN, TaN or the like may be used. Further, although Cu is adopted as the material of the through-hole wiring 24 and the thermal via 26, it is not limited to Cu, and for example, Ni, Al, etc. may be adopted.

  As shown in FIGS. 8 and 9, the light distribution substrate 30 is formed on one surface side of the silicon substrate 30a (on the left side in FIG. 8C) via conductor patterns 35, 35 via through-hole wirings 34, 34. Conductive patterns 37 and 37 electrically connected to each other are formed, and a metal layer for bonding 38 for bonding to the light detection element forming substrate 40 is formed, and the other surface side of the silicon substrate 30a (FIG. 8). On the right side in (c), two conductor patterns 35 and 35 that are joined to and electrically connected to the two conductor patterns 27b and 27b of the base substrate 20 are formed, and the joining metal of the base substrate 20 is formed. A bonding metal layer 36 to be bonded to the layer 29 is formed.

  Further, the light distribution substrate 30 has two through-holes 32 in which the above-described two through-hole wirings 34 are respectively formed in the thickness direction of the silicon substrate 30a. An insulating film 33 made of a thermal oxide film (silicon oxide film) is formed across the other surface and the inner surface of each through hole 32, and each conductor pattern 35, 35, 37, 37 and each bonding metal layer 36, 38 is electrically insulated from the silicon substrate 30a. Here, each of the conductor patterns 35, 35, 37, 37 and each of the bonding metal layers 36, 38 is a laminated film of a Ti film formed on the insulating film 33 and an Au film formed on the Ti film. The conductor patterns 35 and 35 on the one surface side of the silicon substrate 30a and the bonding metal layer 36 are formed at the same time, and the conductor patterns 37 and 37 and the bonding metal layer 38 on the other surface side of the silicon substrate 30a. Are formed at the same time. In this embodiment, the thickness of the Ti film on the insulating film 33 is set to 15 to 50 nm, and the thickness of the Au film on the Ti film is set to 500 nm. However, these numerical values are only examples and are particularly limited. Not what you want. Here, the material of each Au film is not limited to pure gold, and may be added with impurities. Further, although a Ti film is interposed as an adhesion improving layer for adhesion between each Au film and the insulating film 33, the material of the adhesion layer is not limited to Ti, for example, Cr, Nb, Zr, TiN, TaN or the like may be used. Further, although Cu is adopted as the material of the through-hole wiring 34, it is not limited to Cu, and for example, Ni, Al or the like may be adopted.

  As shown in FIGS. 10 and 11, the photodetecting element forming substrate 40 has two conductor patterns 37, 37 of the light distribution substrate 30 on one surface side (right side in FIG. 10C) of the silicon substrate 40a. The two conductive patterns 47a and 47b that are joined together and electrically connected are formed, and the joining metal layer 48 joined to the joining metal layer 38 of the light distribution substrate 30 is formed. Here, the photodetecting element 4 is configured by a photodiode, and one of the two conductor patterns 47a and 47b formed on the photodetecting element forming substrate 40 (upper conductor pattern 47a in FIG. 11). Is electrically connected to the p-type region 4a of the photodiode constituting the photodetecting element 4, and the other conductor pattern 47b (lower conductor pattern 47b in FIG. 11) is connected to the n-type region 4b of the photodiode. It is electrically connected to the silicon substrate 40a that constitutes it.

  Further, in the photodetecting element forming substrate 40, an insulating film 43 made of a silicon oxide film is formed on the one surface side of the silicon substrate 40a, and the insulating film 43 also serves as an antireflection film of the photodiode. Further, in the light detection element forming substrate 40, the one conductor pattern 47a is electrically connected to the p-type region 4a through the contact hole 43a formed in the insulating film 43, and the other conductor pattern 47b is connected to the insulating film 43. The n-type region 4b is electrically connected through the formed contact hole 43b. Here, each of the conductor patterns 47a and 47b and the bonding metal layer 48 is composed of a laminated film of a Ti film formed on the insulating film 43 and an Au film formed on the Ti film, and is formed at the same time. It is. In this embodiment, the thickness of the Ti film on the insulating film 43 is set to 15 to 50 nm, and the thickness of the Au film on the Ti film is set to 500 nm. However, these numerical values are only examples and are particularly limited. Not what you want. Here, the material of each Au film is not limited to pure gold, and may be added with impurities. Further, although a Ti film is interposed as an adhesion improving layer for adhesion between each Au film and the insulating film 43, the material of the adhesion layer is not limited to Ti, for example, Cr, Nb, Zr, TiN, TaN or the like may be used.

  In the formation of the mounting substrate 2 described above, for example, as shown in FIG. 2, the silicon substrate 40a on which the light detecting element 4, the insulating film 43, the conductor patterns 47a and 47b, and the bonding metal layer 48 are formed, and the light distribution. After performing a first bonding step for bonding the substrate 30 to the substrate 30 by a room temperature bonding method capable of direct bonding at a low temperature, a polishing step for polishing the silicon substrate 40a to a desired thickness is performed, and then inductively coupled plasma is performed. After the light detection element forming substrate 40 is completed by performing a light extraction window forming step of forming the light extraction window 41 on the silicon substrate 40a using an (ICP) type dry etching apparatus or the like, the light emitting element 1 is mounted. The second bonding step of bonding the base substrate 20 and the light distribution substrate 30 by a room temperature bonding method or the like may be performed. In the normal temperature bonding method, the bonding surfaces are contacted with each other after the bonding surfaces are cleaned and activated by irradiating the bonding surfaces with argon plasma, ion beam or atomic beam in vacuum before bonding. And bond directly at room temperature.

  In the first bonding step, the bonding metal layer 48 of the silicon substrate 40a and the bonding metal layer 38 of the light distribution substrate 30 are bonded, and the conductor patterns 47a and 47b of the silicon substrate 40a and the light distribution layer are bonded. The conductor patterns 37 and 37 of the substrate 30 are joined and electrically connected. Here, since the joint portions of the conductor patterns 47a and 47b and the conductor patterns 37 and 37 are shifted from the region overlapping the through-hole wiring 34, the joint surfaces of the conductor patterns 47a and 47b and the conductor patterns 37 and 37 are mutually connected. The flatness of the substrate can be increased, the junction yield can be increased, and the junction reliability can be increased. In the second bonding step, the bonding metal layer 29 of the base substrate 20 and the bonding metal layer 36 of the light distribution substrate 30 are bonded, and the conductor patterns 25b and 25b of the base substrate 20 and the light distribution layer are combined. The conductor patterns 35 and 35 of the substrate 30 are joined and electrically connected. Here, since the joint portions of the conductor patterns 25b and 25b and the conductor patterns 35 and 35 are shifted from the region overlapping the through-hole wiring 24 and the region overlapping the through-hole wiring 34, the conductor patterns 25b and 25b and the conductor pattern 35 are arranged. , 35, the flatness of the mutual joint surfaces can be increased, the joint yield can be increased, and the joint reliability can be enhanced. In the present embodiment, in the light distribution substrate 30, each of the conductor patterns 37, 37 on the one surface side constitutes a first connecting metal layer, and each of the conductor patterns 35, 35 on the other surface side is the first. 2 connecting metal layers. Further, each of the conductor patterns 47a and 47b formed on the photodetecting element forming substrate 40 constitutes a third connection metal layer, and each of the conductor patterns 25b and 25b formed on the base substrate 20 is a fourth connection. Constitutes a metal layer.

  Further, the above-described translucent member 3 is formed using a translucent substrate made of a translucent material (for example, silicone resin, acrylic resin, epoxy resin, polycarbonate resin, glass, or the like). Here, the translucent member 3 is formed in a rectangular plate shape having the same outer peripheral shape as the mounting substrate 2, and all of the light emitted from the light emitting element 1 is formed on the light extraction surface opposite to the mounting substrate 2 side. A fine concavo-convex structure that suppresses reflection is formed. Here, the fine concavo-convex structure formed on the light extraction surface of the translucent member 3 is formed such that many fine concave portions have a two-dimensional periodic structure. The fine concavo-convex structure described above may be formed using, for example, a laser processing technique, an etching technique, an imprint lithography technique, or the like. Further, the period of the fine concavo-convex structure may be appropriately set within a range of about ¼ to 100 times the emission peak wavelength of the light emitting element 1.

  In manufacturing the light emitting device of the present embodiment described above, a silicon wafer capable of forming a large number of the base substrate 20, the light distribution substrate 30, and the light detection element forming substrate 40 as the silicon substrates 20a, 30a, and 40a described above. And using the wafer-like thing (translucent wafer) on which a large number of translucent members 3 can be formed as the above-described translucent substrate, the above-described first bonding step, polishing step, and light extraction window forming step Mounting after the second bonding step, the sealing portion forming step of forming the sealing portion 5 by filling the housing recess 2a of the mounting substrate 2 with a translucent material for sealing, and forming the sealing portion 5 The wafer level package structure is formed by performing each process such as a third bonding process for bonding the substrate 2 and the translucent member 3 at the wafer level, and then divided into the size of the mounting substrate 2 by the dicing process. ing. Therefore, the base substrate 20, the light distribution substrate 30, the light detection element formation substrate 40, and the translucent member 3 have the same outer size, so that a small package can be realized and manufacturing is facilitated. Further, the relative positional accuracy between the mirror film 39 on the light distribution substrate 30 and the light detection element 4 on the light detection element formation substrate 40 can be increased, and the light emitted from the light emitting element 1 to the side is mirror film. The light is reflected by 39 and guided to the light detection element 4.

  Hereinafter, a method for forming the light distribution substrate 30 for forming the light distribution substrate 30 before the second bonding step for bonding the light emitting element 1 to the base substrate 20 will be described with reference to FIG.

  First, a mask for forming silicon oxide films 41a and 41b on the one surface side (the upper surface side in FIG. 1A) and the other surface side (the lower surface side in FIG. 1A) of the silicon substrate 30a by thermal oxidation. The structure shown in FIG. 1A is obtained by performing the oxide film forming step.

  Thereafter, in order to form a mask for forming the above-described through-hole 32 in the silicon substrate 30a, the silicon oxide film 41b on the other surface side of the silicon substrate 30a is patterned using photolithography technology and etching technology, Using the patterned silicon oxide film 41b as a mask, the silicon substrate 30a reaches the silicon oxide film 41a on the one surface side from the other surface side (that is, the silicon oxide film 41b on the other surface side of the silicon substrate 30a is masked). The silicon oxide film 41a on the one surface side is used as an etching stopper layer to penetrate through the silicon substrate 30a), and a through hole forming process for forming a through hole 32 is performed, followed by silicon oxide films 41a and 41b. Is removed by etching, and then the silicon substrate 30a is By performing an insulating film forming step of forming an insulating film 23 made of a silicon oxide film on the surface side, the other surface side, and the inner surface (inner peripheral surface) of the through-hole 32 by a thermal oxidation method, FIG. Get the structure. Here, as an etching apparatus in the through-hole forming step, for example, an inductively coupled plasma (ICP) type dry etching apparatus is used, and the thickness of the silicon substrate 30a is set to about 200 μm to 500 μm by appropriately setting the etching conditions. However, the aspect ratio of the through hole 32 can be set to a high aspect ratio of 20 to 50.

  Thereafter, a photolithography technique and an etching technique are used to form a mask for forming a recess 31a whose inner surface is a mirror surface having a (111) plane at a portion corresponding to the opening window 31 on the one surface of the silicon substrate 30a. Then, the insulating film 33 on the one surface side of the silicon substrate 30a is patterned, and the recess 31a is etched by etching the silicon substrate 30a from the one surface side to a predetermined depth using the patterned insulating film 33 as a mask. The structure shown in FIG.1 (c) is obtained by performing the recess formation process to form. Here, in the recess forming step, the recess 31a is formed by anisotropic etching using an alkaline solution (for example, KOH aqueous solution, TMAH aqueous solution, etc.).

  After the above-described recess forming step, an oxide film forming step for forming a silicon oxide film 33b on the inner surface and the inner bottom surface of the recess 30a of the silicon substrate 30a is performed, thereby obtaining the structure shown in FIG. In the present embodiment, the through-hole 32 for through-hole wiring is formed in the silicon substrate 30a by the above-described through-hole forming step, insulating film forming step, recess forming step, and oxide film forming step. A recess 31a whose inner surface becomes a mirror surface is formed by forming an insulating film 33 as a silicon oxide film on the inner surface of the through-hole 32 and anisotropically etching a portion corresponding to the opening window 31 from one surface side with an alkaline solution. After the step is formed, a pre-stage process for forming the silicon oxide film 33b on the inner side surface and the inner bottom surface of the recess 31a is configured. In the previous step, the through hole wiring formation process, the insulating film formation process, the recess formation process, and the oxide film formation process are performed in this order, but the recess formation process, the oxide film formation process, the through hole formation process, and the insulation are performed. You may make it perform in order of a film formation process.

  Through-hole wiring formation in which a through-hole wiring 34 made of a metal material (for example, Cu, Ni, Al, etc.) is formed inside the through-hole 32 of the silicon substrate 30a using the electroplating method after the above-mentioned pre-stage process. By performing the process, the structure shown in FIG. When the through-hole wiring 34 is formed by using electroplating, the metal portion that forms the basis of the through-hole wiring 34 is bottom-up grown after the other surface side of the silicon substrate 30a is closed with a metal thin film or the like. After that, the unnecessary portion of the metal portion is removed by CMP or the like to form the through hole wiring 34.

  After the above-described through-hole wiring forming process, a mirror film forming process for forming a mirror film 39 on the silicon oxide film 33b on the inner surface of the recess 30a of the silicon substrate 30a is performed, as shown in FIG. Get the structure. In the mirror film forming step, an Al film serving as the base of the reflective film is formed on the one surface side of the silicon substrate 30a by sputtering or the like, and subsequently, a silicon oxide film serving as the base of the protective film is formed by CVD. After forming the film by the method or the like, the mirror film 39 is formed by patterning the laminated film of the Al film and the silicon oxide film.

  After the above-described mirror film forming step, the back side metal layer is formed to form the conductor patterns (second connecting metal layers) 35 and 35 and the bonding metal layer 36 on the other surface side (back side) of the silicon substrate 30a. By performing the process, the structure shown in FIG. In the backside metal layer forming step, a laminated film of a Ti film and an Au film is formed on the other surface side of the silicon substrate 30a by a sputtering method or the like, and then the laminated film is used by a photolithography technique and an etching technique. Then, the conductive patterns 35 and 35 and the bonding metal layer 36 (see FIG. 8C) are formed by patterning.

  After the above-described back side metal layer forming step, the front side metal layer for forming the metal layer 37a serving as the basis of the conductor patterns 37, 37 (first connecting metal layer) on the entire surface of the one surface side of the silicon substrate 30a. By performing the formation process, the structure shown in FIG. Here, in the surface side metal layer forming step, a metal layer 37a made of a laminated film of a Ti film and an Au film is formed on the entire surface of the silicon substrate 30a on the one surface side by a sputtering method or the like. In this embodiment, the first metal layer for connection is formed on the one surface side of the silicon substrate 30a and the second surface side is formed on the other surface side in the back surface side metal layer forming step and the surface side metal layer forming step. The metal layer formation process which forms the metal layer for a connection is comprised.

  After the above-described metal layer forming step, a resist mask 135 is formed on the other surface side of the silicon substrate 30a to cover a portion other than the portion corresponding to the opening window 31, and the conductor patterns 37 and 37 on the one surface side of the silicon substrate 30a and The structure shown in FIG. 1I is obtained by performing a resist mask forming process for forming a resist mask 136 that covers a portion corresponding to the bonding metal layer 38. Note that in the resist mask formation step, the resist mask 135 and the resist mask 136 may be formed in either order.

  After the resist mask forming step, the silicon substrate 30a is formed from the other surface side of the laminated film of the silicon oxide film 33b formed on the inner bottom surface of the recess 31a and the metal layer 37a as an etching stopper layer. The structure shown in FIG. 1 (j) is obtained by performing a back surface side etching step in which dry etching is performed to a depth reaching the depth. Here, in the back side etching process, vertical processing is performed using an ICP type dry etching apparatus, but the dry etching apparatus is not particularly limited.

  After the above-described back side etching step, the silicon oxide film at the portion facing the opening window 31 is removed by etching, and then the metal layer 37a is patterned by wet etching to form a conductor pattern (first connecting metal layer) 37. , 37 and the wet etching process for forming the opening window 31 are performed to obtain the structure shown in FIG. Here, the Ti film of the metal layer 37a is wet etched with hydrogen peroxide, and the Au film is wet etched with iodine. In the present embodiment, the resist mask 135 covers portions other than the portion corresponding to the opening window 31 on the other surface side of the silicon substrate 30a in the resist mask forming step, the back surface side etching step, and the wet etching step, and then the opening window. An etching process for completing the opening window 31 is formed by etching the part corresponding to 31 so as to reach the recess 31a from the other surface side.

  After the above-described etching process for completing the opening window, the light distribution substrate 30 having the structure shown in FIG. 1 (l) is performed by performing a mask removing process for removing the resist masks 135 and 156 with an organic solvent (for example, acetone). Get. In forming the light distribution substrate 30, all the above steps are performed at the wafer level.

  According to the method of manufacturing the light emitting device of the present embodiment described above, the through hole 32 for the through hole wiring 34 is formed in the silicon substrate 30a, and then the insulating film 33 made of a silicon oxide film is formed on the inner surface of the through hole 32. At the same time, a portion corresponding to the opening window 31 is anisotropically etched from the one surface side with an alkaline solution to form a recess 31a having a mirror surface on the inner surface, and then formed on the inner surface and the inner bottom surface of the recess 31a. By performing the pre-stage process for forming the silicon oxide film 33b, the recess 31a whose inner surface is formed by a mirror surface with a small surface roughness can be formed. In the pre-stage process, the thickness of the silicon substrate 30a is formed. Since the recess 31a is formed without forming the opening window 31 penetrating in the direction, the through-hole wiring 34 is formed using electroplating in the through-hole wiring forming process. Can. Here, the depth dimension of the recess 31a formed in the above-described recess forming step is such that the thickness dimension of the diaphragm portion between the other surface of the silicon substrate 30a and the inner bottom surface of the recess 31a is mounted on the base substrate 20. It may be set so as to be smaller than the thickness dimension of the light emitting element 1, but if the thickness dimension of the diaphragm portion becomes too thin, the diaphragm portion is likely to be damaged in the step after the recess forming step, It can be considered that the yield is significantly reduced or the manufacturing apparatus is contaminated or broken due to broken pieces. In particular, when performing CMP in the above-described through-hole wiring forming process, it is desirable that the thickness of the diaphragm portion is 10 μm or more. Therefore, the depth of the recess 31a is set so that the thickness of the diaphragm portion is 10 μm or more. It is desirable to set the size.

  In addition, according to the method for manufacturing the light emitting device described above, the silicon oxide film 33b is formed on the inner side surface and the inner bottom surface of the recess 31 prior to the through hole wiring forming step. It is possible to prevent the plating precipitation part (metal part) from being formed on the inner side surface of the location 31a and to increase the surface roughness of the inner side surface of the recess 31a, and the concave portion after the through-hole wiring formation step in the mirror film formation step. Since the mirror film 39 is formed on the silicon oxide film 33b on the inner surface of the location 31a, the surface roughness of the mirror film 39 can be reduced, and the first connecting metal layer and A metal layer forming step for forming a second connection metal layer is performed, and thereafter, the portion other than the portion corresponding to the opening window 31 on the other surface side of the silicon substrate 30a is covered with the resist mask 135 and then the opening window is formed. The portion corresponding to 1 is etched from the other surface side so as to reach the recess 31a, so that an opening window completion etching step for forming the opening window 31 is performed, followed by a mask removal step for removing the resist mask 135. Therefore, it is possible to prevent the surface of the mirror film 39 from being roughened, and as a result, a part of the light emitted from the light emitting element 1 can be efficiently condensed on the light detecting element 4, and the conductor It is possible to prevent the surfaces of the patterns (first connection metal layer) 37, 37, the conductor patterns 35, 35 (second connection metal layer), and the bonding metal layers 38, 36 from being roughened. The yield of each joining process by room temperature joining can be improved and the manufacturing yield can be improved. The inventors of the present application have examined the film thickness of the Au film and the surface roughness of the bonding surface in order to improve the yield when bonding at room temperature with a combination of Au film and Au film (Au—Au). Has been obtained from the experimental results that it is desirable that the RMS roughness of the bonding surface in the Au film is 1.83 nm or less. According to the above manufacturing method, The RMS roughness of the bonding surface of each Au before bonding can be reduced to 1.83 nm or less.

  Further, according to the manufacturing method of the light emitting device described above, in the metal layer forming step, the metal layer 37a serving as the basis of the first connecting metal layer is formed on the one surface side of the silicon substrate 30a. In the etching process for completing the opening window, the silicon substrate 30a is formed using the laminated film of the silicon oxide film 33b and the metal layer 37a formed on the inner bottom surface of the recess 31a as an etching stopper layer. Is dry-etched from the other surface side to a depth reaching the laminated film, and then the silicon oxide film 33b at the portion facing the opening window 31 is removed by etching, and then the metal layer 37a is patterned by wet etching. Since the pattern (first connecting metal layer) 37, 37 and the opening window 31 are formed, the opening window completion etching is performed. Compared with the case where the silicon substrate 30a is dry-etched from the other surface side without the etching stopper layer in the etching process, the surface of the mirror film 39 can be prevented from being roughened, and the chamber and wafer holder of the dry etching apparatus are adversely affected. In addition, when the silicon substrate 30a is dry-etched from the other surface side, the etching stopper layer is compared with the case where a single layer film of the silicon oxide film 33b is used as an etching stopper layer. It is possible to prevent the etching stopper layer from being damaged by the pressure difference between both sides in the thickness direction. When only the metal layer 37a is used as the etching stopper layer, the metal layer 37a serving as the etching stopper layer is ductile and will not be damaged. However, since the surface of the metal layer 37a is sputtered, the sputtered metal May adhere to the inner wall of the chamber of the dry etching apparatus or reattach to the other surface side of the silicon substrate 30a, which may cause a problem of adverse effects. In this embodiment, the silicon oxide film 33b and the metal layer Since the laminated film with 37a is used as an etching stopper layer and dry etching is performed from the other surface side of the silicon substrate 30a, such a problem does not occur.

  Moreover, according to the manufacturing method of the light-emitting device described above, in the bonding step of bonding the light distribution substrate 30 and the base substrate 20 on which the light-emitting element 1 is mounted, the bonding surfaces are activated before bonding. Since the bonding surfaces are brought into contact with each other at room temperature, the junction temperature of the light-emitting element 1 can be prevented from exceeding the maximum junction temperature in the bonding step, and the characteristics of the light-emitting element 1 can be prevented from deteriorating. .

  By the way, in the above-mentioned embodiment, although the visible light LED chip is used as the light emitting element 1, the light emitting element 1 is laminated | stacked on not only a visible light LED chip but an ultraviolet light LED chip, LED chip, and the said LED chip. It may be composed of a phosphor layer formed of a phosphor that is excited by at least light emitted from the LED chip and emits light having a longer wavelength than the LED chip, or an organic EL element. In addition, as the light emitting element 1, for example, after a light emitting portion or the like is epitaxially grown on the main surface side of the crystal growth substrate, a conductive substrate (for example, a Si substrate) that supports the light emitting portion is fixed to the light emitting portion. You may use what removed the board | substrate for crystal growth. The base substrate 20 is not limited to the silicon substrate 20a, and may be formed using, for example, a metal plate. By forming the base substrate 20 using a metal plate, the heat generated in the light emitting element 1 can be radiated more efficiently. It becomes possible.

  The light detection element 4 is not limited to a photodiode, and may be, for example, a color sensor that combines a photodiode and a color filter, or a combination of a photodiode and a wavelength selection filter.

  Moreover, in the said embodiment, although the one light emitting element 1 is mounted in the inner bottom face of the storage recess 2a of the mounting board | substrate 2, the number of the light emitting elements 1 is not specifically limited, A several luminescent color is the same. The light emitting element 1 may be mounted on the inner bottom surface of the storage recess 2a.

It is principal process sectional drawing for demonstrating the formation method of the substrate for light distribution in the light-emitting device of embodiment. It is explanatory drawing of the formation method of the mounting substrate in the light-emitting device same as the above. It is a schematic sectional drawing of a light-emitting device same as the above. It is a general | schematic disassembled perspective view of a light-emitting device same as the above. The mounting board | substrate is shown, (a) is a schematic plan view, (b) is A-A 'schematic sectional drawing of (a), (c) is B-B' schematic sectional drawing of (a). The base board | substrate in the same as the above is shown, (a) is a schematic plan view, (b) is an A-A 'schematic sectional view of (a), and (c) is a B-B' schematic sectional view of (a). It is a schematic bottom view of the base substrate in the same as the above. The light distribution board | substrate in the same as the above is shown, (a) is a schematic plan view, (b) is a schematic cross-sectional view along AA 'in (a), and (c) is a schematic cross-sectional view along BB' in (a). . It is a schematic bottom view of the substrate for light distribution in the same as the above. The optical detection element formation board in the same as above is shown, (a) is a schematic plan view, (b) is an AA 'schematic sectional view of (a), (c) is a BB' schematic sectional view of (a). is there. It is a schematic bottom view of the optical detection element formation board | substrate in the same as the above. It is a schematic sectional drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Mounting board | substrate 2a Storage recess 2c Protrusion part 4 Photodetection element 20 Base board 24 Through-hole wiring 25a Conductor pattern 25b Conductor pattern (4th connection metal layer)
26 Thermal vias 27a, 27b Electrodes for external connection 29 Metal layer for bonding 30 Light distribution substrate 30a Silicon substrate 31 Open window 31a Recess 32 Through hole 33 Insulating film (silicon oxide film)
33b Silicon oxide film 34 Through-hole wiring 35 Conductor pattern (second connecting metal layer)
36 Metal layer for joining 37 Conductor pattern (first metal layer for connection)
37a Metal layer 38 Joining metal layer 39 Mirror film 40 Photodetecting element forming substrate 41 Light extraction window 47a, 47b Conductor pattern (third connecting metal layer)
48 Metal layer for bonding 135 Resist mask 136 Resist mask

Claims (3)

  A light emitting element and a package formed of a mounting substrate having at least one housing recess for housing the light emitting element, the mounting substrate having a protrusion protruding inward from the periphery of the housing recess. And a light detection element that detects light emitted from the light emitting element is provided on the projecting portion. The mounting substrate includes a base substrate on which the light emitting element is mounted on one surface side, and the base substrate. A light detection element forming substrate on which a light extraction window is formed oppositely on one surface side and a light detection element is formed, and a base substrate and a light detection element formation substrate formed using a silicon substrate. It is composed of a light distribution substrate in which an opening window that is interposed and communicated with the light extraction window is formed, and a mirror film that reflects a part of the light emitted from the light emitting element to the light detection element side is formed on the inner side surface of the opening window The light distribution board has through-hole distribution. And a first connecting metal layer electrically connected to the through-hole wiring is formed on one surface side that is the light detection element forming substrate side, and on the other surface side that is the base substrate side A second connection metal layer electrically connected to the through-hole wiring is formed, and the first connection metal layer is electrically connected to the light detection element on the light detection element formation substrate. Manufacturing of a light-emitting device in which the second connecting metal layer is bonded and electrically connected to the fourth connecting metal layer formed on the base substrate by being bonded and electrically connected to the connecting metal layer. In the method, when forming the light distribution substrate before the bonding step of bonding the light distribution substrate and the base substrate on which the light emitting element is mounted, the through holes for the through hole wiring are formed in the silicon substrate. A silicon oxide film is formed on the inner surface of the through hole and opened. Before forming a silicon oxide film on the inner side surface and the inner bottom surface of the recess by forming anisotropically the inner surface as a mirror surface by anisotropically etching the portion corresponding to the window from one surface side with an alkaline solution A through-hole wiring forming step of forming a through-hole wiring inside the through-hole of the silicon substrate using an electroplating method after the step of the previous step, and a recess of the silicon substrate after the through-hole wiring forming step. A mirror film forming step of forming a mirror film on the silicon oxide film on the inner side surface of the substrate; a first connecting metal layer on the one surface side of the silicon substrate after the mirror film forming step; A metal layer forming step of forming a second connecting metal layer on the front surface side, and after the metal layer forming step, a portion other than the portion corresponding to the open window on the other surface side of the silicon substrate is covered with a resist mask, and then the open window Vs. An etching process for completing an opening window by etching a corresponding part so as to reach the recess from the other surface side, and a mask removing process for removing the resist mask after the etching process for completing the opening window; A method for manufacturing a light-emitting device.   In the metal layer forming step, a metal layer serving as a basis of the first connection metal layer is formed on the entire surface of the silicon substrate on the one surface side of the silicon substrate, and the opening In the etching process for window completion, the silicon substrate reaches the laminated film from the other surface side using the laminated film of the silicon oxide film and the metal layer formed on the inner bottom surface of the recess as an etching stopper layer. The first connecting metal layer is formed by performing dry etching to a depth, and then etching away the silicon oxide film at a portion facing the opening window and then patterning the metal layer by wet etching. The method for manufacturing a light emitting device according to claim 1, wherein the opening window is formed.   3. The method for manufacturing a light emitting device according to claim 1, wherein in the bonding step, the bonding surfaces are activated before bonding, and then the bonding surfaces are brought into contact with each other to perform room temperature bonding.

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