JP2004335596A - Mounting structure and method of optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element mounting structure which is capable of driving an optical element at a high speed and less selective for its component members. <P>SOLUTION: The optical element mounting structure 100 comprises a mounting board 10 and the optical element 20 mounted on the mounting board 10. A first electrode connector 21 is provided to the optical element 20, Furthermore, a wiring layer 22 is provided on the mounting board 10 extending from the first electrode connector 21 to the mounting board 10 via the side wall 20a of the optical element 20. The region of the side wall 20a where the wiring layer 22 is formed is tapered forward. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mounting structure of an optical element and a mounting method thereof.
[0002]
[Background Art]
As a method for connecting a wiring pattern on a mounting board and an electrode connection portion of an optical element (light emitting element or light receiving element or the like), wire bonding is generally used. However, when this bonding method is applied, the wire serves as an inductive component, which hinders high-speed driving of the optical element.
[0003]
On the other hand, there is also a method of electrically connecting a wiring pattern on a mounting board to an electrode connection portion of an optical element without using a wire as in flip-chip mounting. However, when this mounting method is applied, both the exit surface (or the entrance surface) of the optical element and the electrode connection portion of the optical element may face the mounting substrate. In this case, light emitted from the optical element (or light incident on the optical element) needs to pass through the mounting substrate. Therefore, in this case, it is necessary to make the material of the mounting substrate permeable to the light. For this reason, as a result of narrowing the selection range of the mounting substrate, there is a limitation on the mounting form of the mounting substrate and the optical element.
[0004]
On the other hand, in this case, when the mounting substrate to be used is made of a material that cannot transmit light emitted from the optical element (or light incident on the optical element), processing such as making a through hole in the substrate is necessary. (For example, see Patent Document 1). However, in order to obtain such a structure, a complicated process is required, and in addition, the mounting form may be greatly restricted.
[0005]
[Patent Document 1]
JP 2000-349307 A
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a mounting structure of an optical element that can drive an optical element at high speed and has a wide selection of constituent members.
[0007]
Another object of the present invention is to provide a method for mounting an optical element that can be manufactured by a simple method.
[0008]
[Means for Solving the Problems]
(1) The mounting structure of the optical element of the present invention is as follows.
A mounting board,
An optical element provided above the mounting substrate,
A first electrode connection portion is provided on the optical element;
Further, a wiring layer is provided extending from above the first electrode connection portion, above the side wall of the optical element, to above the mounting substrate,
At least a region of the side wall where the wiring layer is formed is formed in a forward tapered shape.
[0009]
Here, "the side wall has a forward tapered shape" means that an angle between a surface of the side wall including at least a region where the wiring layer is formed and an upper surface of the mounting substrate is an acute angle. The “upper surface of the mounting substrate” refers to a surface of the mounting substrate on which the optical element is installed.
[0010]
(2) The mounting structure of the optical element of the present invention is as follows.
A mounting board,
An optical element provided above the mounting substrate,
A first electrode connection portion is provided on the optical element;
Side walls of the optical element are covered with an insulating layer,
The thickness of the insulating layer decreases as the distance from the side wall increases,
A wiring layer is provided that extends from above the first electrode connection portion to above the mounting substrate via the insulating layer.
[0011]
(3) The mounting structure of the optical element of the present invention is as follows.
A mounting substrate provided with a concave portion,
An optical element provided in the recess,
A first electrode connection portion is provided on the optical element;
A wiring layer extending from above the first electrode connection portion to above the mounting substrate is provided.
[0012]
In this case, the first electrode connection portion is provided on a surface of the optical element,
The upper surface of the first electrode connection portion and the upper surface of the mounting substrate may be provided at substantially the same height.
[0013]
In this case, a gap can be provided between the concave portion and the optical element.
[0014]
According to the optical element mounting structures (1) to (3), the optical element can be driven at a high speed and the selectivity of the members constituting the mounting structure can be widened. Details will be described in the section of the present embodiment.
[0015]
(4) In the mounting structure of the optical element, the wiring layer may be formed by discharging a droplet to form a wiring layer precursor and solidifying the precursor.
[0016]
Here, the “wiring layer precursor” has a wiring shape formed of a liquid material and refers to a material that becomes a wiring layer when solidified (described later). In addition, the precursor may include not only the discharged material itself but also, for example, a material in the course of solidification.
[0017]
The term “discharge a droplet to form a wiring layer precursor” refers to forming a wiring layer precursor having a predetermined pattern by discharging a droplet. ) Is sometimes called. However, in this case, the droplet to be ejected is not a so-called ink used for printed matter, but a liquid material containing a material constituting the wiring layer, and this material can function as a conductive material constituting the wiring layer. It contains substances. Further, "discharging a droplet" is not limited to the case where the droplet is sprayed at the time of discharging, but also includes a case where each droplet of a liquid material is continuously applied.
[0018]
Further, “solidifying the precursor” means that the liquid material contained in the wiring layer precursor is decomposed or evaporated to remove the liquid material, and the conductive component contained in the wiring layer precursor is solidified. Examples of the case include a case where a resin precursor containing a conductive component is cured by light or heat.
[0019]
(5) The mounting structure of the optical element further includes a circuit section for driving the optical element, and the wiring layer can further extend from above the mounting substrate to the circuit section.
[0020]
Here, the circuit portion is provided on the mounting substrate, the circuit portion is provided with a second electrode connection portion, and the wiring layer extends from above the first electrode connection portion to above the second electrode connection portion. Can be.
[0021]
(6) In the mounting structure of the optical element, the wiring layer may further include a heat sink, and the wiring layer may further extend from above the mounting substrate to the heat sink.
[0022]
(7) In the mounting structure of the optical element, the optical surface of the optical element and the wiring layer may be provided above the same surface of the mounting substrate.
[0023]
In the present application, the “optical surface” refers to a light emitting surface or a light incident surface. For example, when the optical element is a light emitting element, the optical surface is a light emitting surface. Alternatively, when the optical element is a light receiving element, the optical surface is a light incident surface.
[0024]
(8) The mounting method of the optical element of the present invention is as follows.
A first electrode connection portion is provided, and an optical element having a forward tapered side wall is provided above the mounting substrate;
Discharging a droplet from above the first electrode connection portion to above the mounting substrate through above the side wall of the optical element to form a wiring layer precursor;
Solidifying the precursor to form a wiring layer extending from above the first electrode connection portion, above the side wall, and above the mounting substrate.
[0025]
(9) The mounting method of the optical element of the present invention comprises:
Placing the optical element provided with the first electrode connection portion above the mounting substrate,
Covering the side wall of the optical element with an insulating layer, forming the insulating layer such that the film thickness decreases as the distance from the side wall increases;
Discharging a droplet from above the first electrode connection portion to above the mounting substrate via the insulating layer to form a wiring layer precursor;
Solidifying the precursor to form a wiring layer extending from above the first electrode connection portion to above the mounting substrate via the insulating layer.
[0026]
(10) The mounting method of the optical element of the present invention is as follows.
Provide a recess in the mounting board,
Placing the optical element provided with the first electrode connection portion in the recess,
Discharging a droplet from above the first electrode connection portion to above the mounting substrate to form a wiring layer precursor;
Solidifying the precursor to form a wiring layer extending from above the first electrode connection to above the mounting substrate.
[0027]
According to the mounting methods of the optical elements (8) to (10), it is possible to obtain a mounting structure of the optical element in which the optical element can be driven at a high speed and the selectivity of the constituent members is wide by a simple method. it can.
[0028]
(11) In the mounting method of the optical element, the discharge of the droplet can be performed by an inkjet method. According to this method, it is possible to finely adjust the discharge amount of the droplet, so that the droplet having a predetermined size can be landed.
[0029]
(12) In the method for mounting an optical element, the wiring layer precursor is further formed by discharging droplets from above the mounting substrate to a circuit section for driving the optical element. Can be formed to extend from above the mounting board to the circuit portion.
[0030]
Here, the circuit portion is provided on the mounting substrate, the circuit portion is provided with a second electrode connection portion, and the wiring layer precursor is provided from the first electrode connection portion via the side wall of the optical element. Drops are formed on the second electrode connection portion by discharging and the wiring layer precursor is cured so that the wiring layer extends from above the first electrode connection portion to above the second electrode connection portion. Can be formed.
[0031]
(13) In the method for mounting an optical element, the wiring layer precursor is further formed by discharging droplets from above the mounting substrate to a heat sink, and curing the wiring layer precursor, thereby forming the wiring layer precursor. The layer may be formed to extend from above the mounting substrate to the heat sink.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0033]
1. Optical element mounting structure
FIG. 1 is a cross-sectional view schematically showing a mounting structure of the optical element according to the present embodiment. FIG. 2 is a plan view schematically showing a mounting structure of the optical element shown in FIG. FIG. 3 is an enlarged schematic view near the optical element shown in FIG. FIG. 1 is a diagram schematically showing a cross section taken along line AA of FIG.
[0034]
As shown in FIG. 1, the structure (mounting structure of an optical element) 100 of the present embodiment includes a mounting substrate 10 and an optical element 20 provided above the mounting substrate 10. Further, the structure 100 includes a circuit unit 30. In this embodiment, the case where the circuit unit 30 is formed on the mounting substrate 10 will be described. However, the circuit unit 30 may be provided on the mounting substrate 10 instead.
[0035]
Although the material of the mounting substrate 10 is not particularly limited, for example, a plastic substrate such as a silicon substrate, a glass substrate, or an epoxy substrate can be used. In the present embodiment, a case where the mounting substrate 10 is a silicon substrate will be described. In this case, the circuit section 30 can be directly formed on the mounting board 10 as shown in FIGS.
[0036]
The optical element 20 is a light emitting element or a light receiving element. This optical element 20 has an optical surface (not shown). This optical surface is provided on the upper surface 20 b of the optical element 20. Examples of the light emitting element include a light emitting diode, a surface emitting laser, and an EL device. Examples of the light receiving element include a photodiode and a solid-state imaging device. The optical element 20 can be fixed to the mounting substrate 10 by, for example, an adhesive (not shown).
[0037]
The optical element 20 is electrically connected to the circuit section 30 by the wiring layer 22. Specifically, the optical element 20 is provided with a first electrode connection portion 21, and a wiring layer 22 is formed on the first electrode connection portion 21. That is, the first electrode connection layer 21 of the optical element 20 is electrically connected to the second electrode connection layer 31 of the circuit unit 30 via the wiring layer 22. The first electrode connection part 21 is provided on the surface of the optical element 20. In the present embodiment, an example is shown in which the first electrode connection portion 21 is provided on the upper surface 20b of the optical element 20.
[0038]
Note that the first and second electrode connection portions 21 and 31 can take various forms. For example, in the present embodiment, a case is shown in which the first and second electrode connection portions 21 and 31 are electrode pads. 1 to 3 show one first electrode connection portion 21 provided on one optical element 20, but a plurality of first electrode connection portions 21 are provided on one optical element 20. Alternatively, one circuit section 30 may be provided with a plurality of second electrode connection sections 31. In this case, each first electrode connection part 21 can be connected to another wiring layer 22. In this case, the first and second electrode connection portions 21 and 31 may be formed of different materials. The above points are similarly applied to other embodiments described later.
[0039]
Further, the optical element 20 may be an optical element array including a plurality of optical elements. This is the same in other embodiments described later. Further, a projection (not shown) may be provided on the upper part of the optical element 20. According to this configuration, a step is formed above the optical element 20. In this case, the first electrode connecting portion 21 may be provided on the upper surface of the convex portion, or may be provided on the surface of the optical element 20 other than the convex portion.
[0040]
The wiring layer 22 is provided on the first electrode connecting portion 21 and above the side wall 20 a of the optical element 20. Further, in the present embodiment, the wiring layer 22 extends from above the first electrode connection section 21 of the optical element 20 to above the second electrode connection section 31 of the circuit section 30. Specifically, as shown in FIG. 3, the wiring layer 22 extends from above the first electrode connecting portion 21 of the optical element 20, above the side wall 20 a and above the mounting substrate 10 (on the upper surface 10 a), and 30 extends to above the second electrode connection portion 31. If necessary, an insulating material (not shown) may be formed on the upper surface 10a of the mounting board 10, and the wiring layer 22 may be provided on the insulating material. For example, when the mounting substrate 10 is a silicon substrate, by providing the wiring layer 22 on the upper surface 10a with the insulating material interposed therebetween, the circuit (for example, the circuit unit 30) in which the wiring layer 22 is provided in the mounting substrate 10 is provided. Can be reduced.
[0041]
The wiring layer 22 discharges droplets 22b from the first electrode connecting portion 21 to the second electrode connecting portion 31 to form a wiring pattern precursor 22a having a predetermined pattern, and solidifies the wiring pattern precursor 22a. It is formed by this.
[0042]
The circuit unit 30 is a circuit for driving the optical element 20. Here, the case where the circuit unit 30 is directly formed on the mounting substrate 10 is shown, but the circuit unit 30 can be separately installed on the mounting substrate 10 instead.
[0043]
Both the wiring layer 22 and the optical surface of the optical element 20 are provided above the same surface (upper surface 10 a) of the mounting substrate 10.
[0044]
As shown in FIGS. 1 to 3, the side wall 20 a of the optical element 20 has a forward tapered shape. That is, as shown in FIG. 3, the angle θ formed between the side wall 20a and the upper surface 10a of the mounting substrate 10 is an acute angle.
[0045]
The side wall 20a is preferably covered with an insulating material (not shown). This insulating material insulates the optical element 20 from the wiring layer 22 on the side wall 20a. In the present embodiment, a case is shown in which the side walls 20a of the optical element 20 are all forward-tapered.
[0046]
In the present embodiment, an example in which the wiring layer 22 extends from above the first electrode connecting portion 21 of the optical element 20 to above the second electrode connecting portion 31 of the circuit portion 30 has been described. The connection destination is not limited to the circuit portion 30, and the wiring layer 22 extends from above the first electrode connection portion 21 of the optical element 20 to above the side wall 20 a and above the mounting board 10 to the heat sink (not shown). May be. This can be similarly applied to other embodiments described later. In this case, the heat dissipation of the optical element 20 can be enhanced by the heat sink.
[0047]
2. Optical element mounting method
Next, a method for mounting the optical element according to the present embodiment will be described with reference to FIGS. FIG. 4 is a cross-sectional view schematically showing one step of the mounting method of the optical element of the present embodiment.
[0048]
(1) Installation of the optical element 20
First, the side wall 20a of the optical element 20 is formed in a forward tapered shape. As a method of forming the side wall 20a in a forward tapered shape, for example, there are a method using dry etching and a method using wet etching. If the optical device 20 is not affected on other parts of the mounting substrate 10 such as the mounting substrate 10 and the circuit portion 30, the side wall 20a of the optical element 20 is tapered after the optical element 20 is set on the mounting substrate 10. It may be processed into a shape. Alternatively, when the optical element 20 is cut out from a substrate (not shown) used for manufacturing the element, the side wall 20a of the optical element 20 may be processed to have a forward tapered shape using, for example, a dither or the like.
[0049]
Next, as shown in FIG. 4, the optical element 20 is set above the mounting substrate 10. For example, the optical element 20 can be fixed to the mounting substrate 10 with an adhesive (not shown). In addition, if necessary, an insulating material (not shown) is formed on the side wall 20 a of the optical element 20.
[0050]
(2) Formation of wiring layer 22
The formation of the wiring layer 22 mainly includes a step of discharging the droplet 22b and a step of solidifying the components of the wiring layer in the droplet 22b. Specifically, in the discharging step, as shown in FIG. 4, the droplet 22b is discharged from the first electrode connecting portion 21 to the second electrode connecting portion 31 of the circuit portion 30 via the side wall 20a and the mounting substrate 10. I do. The droplet 22b is discharged from the droplet discharge unit 120 of the droplet discharge head. Thus, a wiring layer precursor 22a having a predetermined pattern is formed. Next, in the solidification step, the wiring layer precursor 22a is solidified to form the wiring layer 22 (see FIGS. 1 to 3).
[0051]
In FIG. 4, for easy understanding, the droplet discharge unit 120 is described in the form of a nozzle, but need not necessarily be a nozzle. For example, the droplet discharge unit 120 may have a hole shape.
[0052]
Hereinafter, the discharge step and the solidification step will be described more specifically. The pattern of the wiring layer 22 is not limited to those shown in FIGS.
[0053]
(Discharge process)
In this embodiment mode, a liquid material (a droplet 22b) containing a conductive component is discharged by a droplet discharge method. Thereby, the wiring layer precursor 22a is formed (see FIG. 4).
[0054]
The droplet 22b is formed of a liquid in which a conductive component is dispersed in a dispersion medium. The conductive component used here is not only metal fine particles containing any of gold, silver, copper, palladium, and nickel, but also fine particles of a conductive polymer or a superconductor.
[0055]
The conductive component may be used by coating the surface with an organic substance or the like in order to improve dispersibility. Examples of the coating material for coating the surface of the conductive component include a polymer material such as gelatin and polyvinyl alcohol, and citric acid.
[0056]
The dispersion medium to be used is not particularly limited as long as it can disperse the above-mentioned conductive components, does not cause aggregation, and does not adversely affect the optical element and the mounting substrate. For example, in addition to a general solvent, a thermosetting resin or a photocurable resin (for example, a phenol resin or an epoxy resin) can be used as the dispersion medium.
[0057]
(Solidification process)
Next, the wiring layer 22 is formed by solidifying the wiring layer precursor 22a. Specifically, the conductive component contained in the wiring layer precursor 22a is solidified. Thus, a wiring layer 22 containing a conductive component is formed. According to this method, the wiring layer 22 can be formed by a simple method.
[0058]
Examples of the solidification method include heat treatment and / or light irradiation. Hereinafter, the methods of heat treatment and light irradiation will be described respectively.
[0059]
{Heat treatment}
By the heat treatment, for example, the liquid substance contained in the wiring layer precursor 22a can be removed by evaporation and / or decomposition. Thus, the wiring layer 22 made of the conductive component is formed.
[0060]
Further, for example, when the wiring layer precursor 22a is made of a liquid material in which the conductive component is dispersed in a thermosetting phenol resin or an epoxy resin, the wiring is formed by curing the resin by heat treatment. You. In this case, when the wiring layer precursor 22a contains a solvent, the solvent can be removed by evaporation and / or decomposition by heat treatment. Thus, the wiring layer 22 is made of a resin in which the conductive component is dispersed.
[0061]
The heat treatment can be performed by lamp annealing, for example, in addition to a normal hot plate heating the substrate or an electric furnace. The light source of the light used for the lamp annealing is not particularly limited, but an infrared lamp, a xenon lamp, a YAG laser, an argon laser, a carbon dioxide laser, an excimer laser such as XeF, XeCl, XeBr, KrF, KrCl, ArF, ArCl, etc. Can be used as
[0062]
｛Light irradiation｝
For example, when the wiring layer precursor 22a is made of a liquid material in which the conductive component is dispersed in a photocurable phenol resin or an epoxy resin, the resin is cured by light irradiation. Thereby, the wiring layer 22 made of the resin in which the conductive component is dispersed can be formed.
[0063]
Note that the solidification step can be performed simultaneously with the discharge step of the wiring layer precursor 22a. For example, the droplet 22b is discharged onto the mounting substrate 10 that has been heated in advance, or the inkjet head (not shown) including the droplet discharge unit 120 (see FIG. 4) is cooled to disperse the dispersion medium having a low boiling point. By using, for example, the solidification can be advanced immediately after the droplet 22b lands on the mounting substrate 10.
[0064]
In addition, the droplets 22b are ejected at intervals without being adjacent to each other to be semi-cured, and the droplets 22b are ejected again in the gaps. The wiring layer 22 may be formed by forming the body 22a and then completely curing the obtained wiring layer precursor 22a.
[0065]
3. Action effect
(1) First, the range of choice of the material of the mounting substrate 10 can be expanded. For example, when the mounting substrate 10 is formed of a plastic substrate such as an epoxy substrate, the optical element 20 is provided above the mounting substrate 10, a conductive layer is formed on the mounting substrate 10, and the conductive layer is patterned to form a wiring. Forming a layer may cause the etching conditions or etchants used in patterning to remove or dissolve the plastic substrate. Therefore, in this case, the range of selection of the material of the mounting substrate 10 is narrowed.
[0066]
On the other hand, according to the present embodiment, a wiring layer precursor 22a having a predetermined pattern is formed by discharging the droplet 22b, and the wiring layer precursor 22a is solidified to form the wiring layer 22. Thus, a wiring layer having a predetermined pattern can be formed without using an etching step. Thereby, the wiring layer 22 having a predetermined pattern can be obtained without affecting the mounting substrate 10. As a result, the range of selection of the material of the mounting substrate 10 can be expanded.
[0067]
(2) Second, the first electrode connection part 21 of the optical element 20 is electrically connected to the second electrode connection part 31 of the circuit part 30 via the wiring layer 22. This eliminates the need for connection by wire bonding or the like. As a result, since there is no inductive component such as a wire, the speed of the optical element 20 can be increased.
[0068]
(3) Third, the side wall 20a of the optical element 20 is formed in a forward tapered shape. Thereby, the wiring layer 22 can be reliably formed. The reason will be described below.
[0069]
The wiring layer 22 is formed by discharging a droplet 22b to form a wiring layer precursor 22a having a predetermined pattern, and solidifying the wiring layer precursor 22a. In the present embodiment, if the difference between the film thickness of the optical element 20 and the film thickness of the wiring layer 22 is large, unless the side wall 20 a of the optical element 20 is in a forward tapered shape, It is difficult to land 22b on the side wall 20a of the optical element 20. That is, in this case, it is difficult to form the wiring layer 22 on the side wall 20a.
[0070]
On the other hand, according to the present embodiment, at least the region where the wiring layer 22 is formed in the side wall 20a of the optical element 20 is formed in a forward tapered shape. Thus, the droplet 22b can be easily landed above the side wall 20a. Thereby, the wiring layer 22 can be reliably formed from the first electrode connection portion 21 to above the side wall 20a.
[0071]
[Second embodiment]
1. Optical element mounting structure
FIG. 5 is a cross-sectional view schematically illustrating a mounting structure of the optical element according to the present embodiment. FIG. 6 is a plan view schematically showing a mounting structure of the optical element shown in FIG. FIG. 7 is an enlarged schematic view near the optical element shown in FIG. FIG. 6 is a diagram schematically showing a cross section taken along line AA of FIG.
[0072]
The structure (mounting structure of an optical element) 200 of the present embodiment has a point that an optical element 220 is provided above a mounting substrate 10 as shown in FIGS. Are covered with the insulating layer 24 and a part of the wiring layer 22 is formed on the insulating layer 24, and thus have a different configuration from the structure 100 of the first embodiment. Except for the points described above, the structure 100 has substantially the same configuration as the structure 100 of the first embodiment. Therefore, in principle, the same components as those of the structure 100 of the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
[0073]
The optical element 220 includes an optical surface (not shown), like the optical element 20 according to the first embodiment. In the present embodiment, both the wiring layer 22 and the optical surface of the optical element 220 are provided above the same surface (the upper surface 10a) of the mounting substrate 10.
[0074]
Further, in the optical element 220, similarly to the optical element 20 of the first embodiment, a first electrode connection portion 21 is provided on the surface (upper surface 220b) of the optical element 220, and the first electrode connection portion 21 is provided. The wiring layer 22 is formed on the portion 21.
[0075]
The types of the optical element 220 applicable in this embodiment are the same as those of the optical element 20 of the first embodiment. Further, the shape and size of the optical element 220 are not limited to those described in the present embodiment. In the present embodiment, as shown in FIG. 2, a case where the planar shape of the optical element 220 is a quadrangle is shown, but the planar shape of the optical element 220 is not particularly limited. It may be trapezoidal.
[0076]
The wiring layer 22 extends from above the first electrode connecting portion 21 of the optical element 20 to above the second electrode connecting portion 31 of the circuit portion 30 via the insulating layer 24 and above the mounting substrate 10 (on the upper surface 10a). ing.
[0077]
2. Optical element mounting method
Next, a method for mounting the optical element according to the present embodiment will be described with reference to FIGS. FIG. 7 is a cross-sectional view schematically showing one step of the method for mounting the optical element of the present embodiment.
[0078]
(1) Installation of the optical element 220
First, the optical element 220 is installed above the mounting board 10 in the same manner as in the case where the optical element 20 is installed above the mounting board 10 in the first embodiment.
[0079]
(2) Formation of insulating layer 24
Next, the side wall 220 a of the optical element 220 is covered with the insulating layer 24. As shown in FIGS. 5 and 7, the insulating layer 24 is formed such that its thickness decreases as the distance from the side wall 220a increases. The insulating layer 24 is made of, for example, a resin.
[0080]
An example of a method for forming the insulating layer 24 will be described. First, after forming a protective layer (not shown) on the upper surface 220b of the optical element 220, droplets (not shown) made of a resin precursor are discharged onto the upper surface of the protective layer. As a precursor of this resin, for example, a precursor of a thermosetting resin or a photocurable resin can be used. After the resin precursor lands on the upper surface of the protective layer, a part thereof flows from the upper surface of the protective layer onto the mounting substrate 10 through the side wall 220a of the optical element 220, and It spreads to a predetermined position on the upper surface 10a. Accordingly, the precursor has a shape in which the thickness decreases as the distance from the side wall 220a increases.
[0081]
Before discharging the resin precursor, a surface treatment is performed on the side wall 220a of the optical element 220 and a portion of the upper surface 10a of the mounting substrate 10 where the insulating layer 24 is formed, so that the resin 220 is wetted by the resin precursor. May be improved. In addition, droplets composed of the resin precursor can be ejected using, for example, a dispenser method or an inkjet method.
[0082]
Next, after the resin precursor is cured by heat or light to obtain a resin, the insulating layer 24 can be formed by removing the protective layer and the resin formed on the protective layer. .
[0083]
(3) Formation of wiring layer 22
Next, as shown in FIGS. 5 to 7, the wiring layer 22 is formed from the first electrode connection part 21 of the optical element 220 to the circuit part 30. The method of forming the wiring layer 22 is the same as the method of forming the wiring layer 22 of the first embodiment, and a detailed description thereof will be omitted.
[0084]
3. Action effect
The mounting structure and the mounting method of the optical element according to the present embodiment have the same operational effects as the mounting structure and the mounting method of the optical element according to the first embodiment.
[0085]
Further, according to the present embodiment, the insulating layer 24 is formed on the side wall 220 a of the optical element 220. Thereby, the wiring layer 22 can be reliably formed. The reason will be described below.
[0086]
In the present embodiment, the wiring layer 22 is formed by discharging droplets (not shown) to form a wiring layer precursor (not shown) having a predetermined pattern, and solidifying the wiring layer precursor. Is done. In this embodiment, if the difference between the thickness of the optical element 220 and the thickness of the wiring layer 22 is large without forming the insulating layer 24, it is difficult to land the droplet on the side wall 220a of the optical element 220. . Therefore, it is difficult to form the wiring layer 22 on the side wall 220a.
[0087]
On the other hand, according to the present embodiment, the insulating layer 24 is formed such that the film thickness decreases as the distance from the side wall 220a increases. This makes it possible to discharge the droplet from above the mounting substrate 10 and easily land the droplet on the insulating layer 24. Accordingly, the wiring layer 22 can be reliably formed from above the first electrode connection portion 21 of the optical element 220 to above the second electrode connection portion 31 of the circuit portion 30 via the insulating layer 24.
[0088]
[Third Embodiment]
1. Optical element mounting structure
FIG. 8 is a cross-sectional view schematically illustrating a mounting structure of the optical element according to the present embodiment. FIG. 9 is a plan view schematically showing a mounting structure of the optical element shown in FIG. FIG. 10 is an enlarged schematic view near the optical element shown in FIG. FIG. 8 is a diagram schematically showing a cross section taken along line AA of FIG.
[0089]
The structure (optical element mounting structure) 300 of the present embodiment is different from the structure in which the concave portion 26 is provided in the mounting substrate 10 as shown in FIGS. This is different from the structure 200 of the second embodiment in that the wiring layer 22 is provided on the optical element 220 and above the mounting substrate 10 without using an insulating layer. Except for the above points, the structure 200 has substantially the same configuration as the structure 200 of the second embodiment. Therefore, in principle, the same components as those of the structure 200 of the second embodiment are denoted by the same reference numerals, and detailed description is omitted.
[0090]
The optical element 220 is provided in the concave portion 26 provided on the mounting substrate 10. The concave portion 26 is formed to have a size at which the optical element 220 can be provided at least. As in the case of the optical element 20 of the first embodiment, a first electrode connection portion 21 is provided on the surface (upper surface 220b) of the optical element 220. Here, it is preferable that the upper surface of the first electrode connection portion 21 and the upper surface 10a of the mounting substrate 10 be set to be substantially the same height.
[0091]
In FIG. 10, the film thickness of the first and second electrode connection portions 21 and 31 is described as being relatively large, but actually, the film thickness of the first and second electrode connection portions 21 and 31 is changed to the thickness of the optical element 220. It can be formed much thinner than the height (similarly in other embodiments). In this case, as shown in FIG. 10, the upper surface 220b of the optical element 220 and the upper surface 10a of the mounting substrate 10 can be set so as to have substantially the same height. Thus, in the same manner as in the first embodiment, when the wiring layer 22 is formed by discharging and solidifying droplets (not shown), the liquid is continuously placed on a surface having substantially the same height. Drops can be landed. Therefore, the droplet can be landed more reliably and stably, so that the wiring layer 22 having a predetermined pattern can be formed more reliably.
[0092]
The wiring layer 22 extends from above the first electrode connecting portion 21 to above the mounting substrate 10 (on the upper surface 10 a) to above the second electrode connecting portion 31 of the circuit portion 30.
[0093]
2. Optical element mounting method
Next, a method of mounting the optical element according to the present embodiment will be described with reference to FIGS. FIG. 11 and FIG. 12 are cross-sectional views schematically showing one step of the mounting method of the optical element of the present embodiment.
[0094]
(1) Formation of recess 26
First, as shown in FIG. 11, a concave portion 26 is formed in the mounting substrate 10. Here, the concave portion 26 is formed to have a depth such that the upper surface of the first electrode connection portion 21 and the upper surface 10a of the mounting substrate 10 become substantially the same height when the optical element 220 is installed in the concave portion 26. Is preferred.
[0095]
The method of forming the concave portion 26 is not particularly limited, and can be appropriately determined according to the type and thickness of the mounting substrate 10. Here, the case where the mounting substrate 10 is a silicon substrate and the concave portion 26 is formed in the mounting substrate 10 by dry etching will be described.
[0096]
A resist layer R1 having a predetermined pattern is formed on the mounting substrate 10 by using a known photolithography process. Next, using the resist layer R1 as a mask, the mounting substrate 10 is etched using, for example, a dry etching method. Thereby, the concave portion 26 is formed at the position where the optical element 20 is formed on the mounting substrate 10. After that, the resist layer R1 is removed.
[0097]
(2) Installation of the optical element 220
Next, as shown in FIG. 12, the optical element 220 is formed in the concave portion 26. The method for installing the optical element 220 can be the same as the method for installing the optical element 20 on the mounting substrate 10 in the first embodiment.
[0098]
(3) Formation of wiring layer 22
Next, as shown in FIGS. 8 to 10, the wiring layer 22 is formed from above the first electrode connection portion 21 of the optical element 220 to above the second electrode connection portion 31 of the circuit portion 30. The method of forming the wiring layer 22 is the same as the method of forming the wiring layer 22 of the first embodiment.
[0099]
In the present embodiment, as shown in FIG. 12, the optical element 220 is provided in the concave portion 26. Here, when the concave portion 26 is formed such that the cross-sectional area of the concave portion 26 is larger than the cross-sectional area of the optical element 220, a gap 28 is generated between the concave portion 26 and the optical element 220. Therefore, in the step of forming the wiring layer 22, it is necessary to prevent conduction between the side wall 220 a of the optical element 220 and the wiring layer 22 as a result of the droplet 22 c entering the gap 28.
[0100]
Here, as shown in FIG. 12, the gap 28 (s in FIG. 12) is made smaller than the diameter (d) of the landed droplet 22c. According to this configuration, it is possible to prevent the landed droplet 22c from dropping into the gap 28 due to the surface tension of the droplet 22c.
[0101]
For example, when the gap 28 (s) is several μm, by setting the diameter (d) of the landed droplet 22c (see FIG. 12) to be more than ten μm, the landed droplet 22c can be Can be effectively prevented from falling.
[0102]
At this time, if the side wall of the concave portion 26 is preliminarily subjected to a process for increasing the liquid repellency, it is possible to more effectively prevent the landed droplet 22c from falling into the gap 28.
[0103]
As described above, even when the gap 28 is formed between the optical element 220 and the concave portion 26, the droplet is ejected to form a wiring layer precursor having a predetermined pattern, and the precursor is cured. The wiring layer 22 can be formed.
[0104]
3. Action effect
The mounting structure and the mounting method of the optical element according to the present embodiment have the same functions and effects as the mounting structure and the mounting method of the optical element according to the first and second embodiments.
[0105]
Furthermore, according to the present embodiment, the step between the optical element 220 and the wiring layer 22 can be eliminated by providing the optical element 220 in the concave portion 26 of the mounting substrate 10. This makes it easier to pattern the wiring layer 22 by discharging droplets.
[0106]
The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the invention includes configurations substantially the same as the configurations described in the embodiments (for example, a configuration having the same function, method, and result, or a configuration having the same object and result). Further, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. Further, the invention includes a configuration having the same operation and effect as the configuration described in the embodiment, or a configuration capable of achieving the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically illustrating a mounting structure of an optical element according to a first embodiment.
FIG. 2 is a plan view schematically showing a mounting structure of the optical element shown in FIG.
FIG. 3 is an enlarged schematic diagram of the vicinity of the optical element shown in FIG.
FIG. 4 is a cross-sectional view schematically showing one manufacturing process of the mounting method of the optical element according to the first embodiment.
FIG. 5 is a cross-sectional view schematically illustrating a mounting structure of an optical element according to a second embodiment.
FIG. 6 is a plan view schematically showing a mounting structure of the optical element shown in FIG.
FIG. 7 is a cross-sectional view schematically showing one manufacturing process of the mounting method of the optical element according to the second embodiment.
FIG. 8 is a cross-sectional view schematically illustrating a mounting structure of an optical element according to a third embodiment.
FIG. 9 is a plan view schematically showing a mounting structure of the optical element shown in FIG.
FIG. 10 is an enlarged schematic view near the optical element shown in FIG.
FIG. 11 is a cross-sectional view schematically showing one manufacturing step of the method for mounting an optical element according to the third embodiment.
FIG. 12 is a cross-sectional view schematically showing one manufacturing process of the method for mounting an optical element according to the third embodiment.
[Explanation of symbols]
Reference Signs List 10 mounting substrate, 10a upper surface of mounting substrate, 20, 220 optical element, 20a, 220a side wall of optical element, 20b, 220b upper surface of optical element, 21 first electrode connection portion, 22 wiring layer, 22a wiring layer precursor, 22b , 22c droplet, 24 insulating layer, 26 concave portion, 28 gap, 30 circuit portion, 31 second electrode connection portion, 100, 200, 300 structure (mounting structure of optical element), 120 droplet discharge portion, R1 resist layer D diameter of droplet 22c s width of gap 28

Claims (17)

A mounting board,
An optical element provided above the mounting substrate,
A first electrode connection portion is provided on the optical element;
Further, a wiring layer is provided extending from above the first electrode connection portion, above the side wall of the optical element, to above the mounting substrate,
An optical element mounting structure, wherein at least a region of the side wall where the wiring layer is formed is formed in a forward tapered shape. A mounting board,
An optical element provided above the mounting substrate,
A first electrode connection portion is provided on the optical element;
Side walls of the optical element are covered with an insulating layer,
The thickness of the insulating layer decreases as the distance from the side wall increases,
A mounting structure for an optical element, wherein a wiring layer extending from above the first electrode connection portion to above the mounting substrate via the insulating layer is provided. A mounting substrate provided with a concave portion,
An optical element provided in the recess,
A first electrode connection portion is provided on the optical element;
An optical element mounting structure, wherein a wiring layer extending from above the first electrode connection portion to above the mounting substrate is provided. In claim 3,
The first electrode connection portion is provided on a surface of the optical element,
An optical element mounting structure, wherein an upper surface of the first electrode connection portion and an upper surface of the mounting substrate are provided at substantially the same height. In claim 3 or 4,
An optical element mounting structure, wherein a gap is provided between the concave portion and the optical element. In any one of claims 1 to 5,
The mounting structure of an optical element, wherein the wiring layer is formed by discharging droplets by an inkjet method to form a wiring layer precursor, and solidifying the precursor. In any one of claims 1 to 6,
Further, a circuit unit for driving the optical element,
The optical element mounting structure, wherein the wiring layer further extends from above the mounting substrate to the circuit portion. In claim 7,
The circuit unit is provided on the mounting board,
A second electrode connection portion is provided in the circuit portion;
The mounting structure of an optical element, wherein the wiring layer extends from over the first electrode connection to over the second electrode connection. In any one of claims 1 to 8,
In addition, including a heat sink,
The optical element mounting structure, wherein the wiring layer further extends from above the mounting substrate to the heat sink. In any one of claims 1 to 9,
An optical element mounting structure, wherein the optical surface of the optical element and the wiring layer are provided above the same surface of the mounting substrate. A first electrode connection portion is provided, and an optical element having a forward tapered side wall is provided above the mounting substrate;
From above the first electrode connection portion, above the side wall of the optical element, to above the mounting substrate, discharge droplets to form a wiring layer precursor,
Solidifying the precursor to form a wiring layer extending from above the first electrode connection portion, above the side wall, to above the mounting substrate,
An optical element mounting method, comprising: Placing the optical element provided with the first electrode connection portion above the mounting substrate,
Covering the side wall of the optical element with an insulating layer, forming the insulating layer such that the film thickness decreases as the distance from the side wall increases;
A droplet is discharged from the first electrode connection portion to the upper side of the mounting substrate via the insulating layer to form a wiring layer precursor,
Solidifying the precursor to form a wiring layer extending from above the first electrode connection portion to above the mounting substrate via the insulating layer;
An optical element mounting method, comprising: Provide a recess in the mounting board,
Placing the optical element provided with the first electrode connection portion in the recess,
From above the first electrode connection part to above the mounting substrate, a droplet is discharged to form a wiring layer precursor,
Solidifying the precursor to form a wiring layer extending from above the first electrode connection portion to above the mounting substrate;
An optical element mounting method, comprising: In any one of claims 11 to 13,
The method of mounting an optical element, wherein the discharging of the droplet is performed by an inkjet method. In any one of claims 11 to 14,
The wiring layer precursor is further formed by discharging droplets from above the mounting substrate to a circuit portion for driving the optical element,
An optical element mounting method, wherein the wiring layer is formed so as to extend from above the mounting substrate to the circuit portion. In claim 15,
The circuit unit is provided on the mounting board,
A second electrode connection portion is provided in the circuit portion;
Forming the wiring layer precursor by discharging droplets from the first electrode connection to the second electrode connection through the side wall of the optical element;
An optical element mounting method, wherein the wiring layer precursor is cured to form the wiring layer so as to extend from above the first electrode connection to above the second electrode connection. In any one of claims 11 to 16,
The wiring layer precursor is further formed by discharging droplets from above the mounting substrate to a heat sink,
A method for mounting an optical element, wherein the wiring layer is formed so as to extend from above the mounting substrate to a heat sink by curing the wiring layer precursor.

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