JP4677651B2 - Optical wiring layer manufacturing method, optical / electrical wiring substrate, manufacturing method thereof, and mounting substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical / electrical wiring board in which optical wiring and electrical wiring are mixed, a method for manufacturing the same, and a mounting board in which optical components and electrical components are mounted on the substrate.
[0002]
[Prior art]
The number of CPU clocks has been increasing year by year in order to make computers that can perform computations faster, and now only about GHz is emerging. As a result, there is a part where high-frequency signals flow in the electrical wiring of copper on the printed circuit board in the computer, so that malfunctions occur due to the generation of noise, and electromagnetic waves are generated and the surroundings are affected. It will be.
In addition, it has been attempted to replace a part of the electrical wiring made of copper on the printed circuit board with an optical wiring made of an optical fiber or an optical waveguide, and to use an optical signal instead of an electrical signal. Techniques for efficient insertion without shifting were difficult and generally could not be matched without relying on skilled workers.
[0003]
In order to solve such a problem, light emitted from a light source is condensed using a lens and conducted in a waveguide. However, also in this case, it is difficult to align the optical axis between the module and the optical waveguide, and mounting the optical component on the optical / electrical wiring board has a drawback that it is very expensive.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the drawbacks of the related art, and an optical wiring layer in which the optical axis between the module and the optical waveguide can be easily aligned, a manufacturing method thereof, high-density mounting or downsizing, and optical It is an object of the present invention to provide an optical / electrical wiring board, a method for manufacturing the same, and a mounting board in which components can be mounted by a simpler method.
[0005]
In order to achieve the above object in the present invention, the invention of claim 1 is an optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer, and the optical wiring The layer changes its propagation direction to 90 ° by using a core that propagates light parallel to the layer, a cladding in which the core is buried, and a dicing saw having a cutting edge of 90 ° with respect to the core. A mirror that is formed to cross each other with an inclination and attached with a metal thin film by vapor deposition, and the light that is located on the clad and collected by the mirror is reflected by the mirror and passes through the core An optical component selected from either a light emitting element or a light receiving element is soldered around a lens that has a lens and the lens is the same member as the clad and is on the opposite side of the substrate having electrical wiring. Pads for optical components provided for And a via hole penetrating the optical wiring layer and the adhesive layer. The optical / electrical wiring board comprising: an optical component pad; and an electrical wiring of a substrate having an electrical wiring; is there.
The invention according to claim 2 is an optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer, and the optical wiring layer emits light parallel to the layer. The core to propagate,
The clad in which the core is buried and a dicing saw having a cutting edge of 90 ° with respect to the core are formed so as to intersect with an inclination that changes the propagation direction to 90 °. A mirror with a thin film, and a lens that is positioned on the cladding and that reflects the light collected by the mirror and reflects the light through the core, and the lens is the same member as the cladding. An optical component pad provided for soldering an optical component selected from either a light emitting element or a light receiving element around the lens on the opposite side of the substrate having the electric wiring; and an electric wiring An electrical component pad provided for soldering an electrical component on the surface of the optical wiring layer on the opposite side of the substrate, and the electrical wiring of the substrate having the optical component or the electrical component pad and the electrical wiring are electrically connected. Connect and light An optical / electrical wiring board comprising a wiring layer and a via hole penetrating the adhesive layer .
The invention according to claim 3 is an optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer, and the optical wiring layer emits light parallel to the layer. The core to be propagated, the clad in which the core is buried, and a dicing saw having a cutting edge of 90 ° with respect to the core are formed so as to intersect with an inclination that changes the propagation direction to 90 °, A mirror on which a metal thin film is attached by vapor deposition; and a lens that is positioned on the cladding and that reflects the light collected by the mirror to be reflected by the mirror and passes through the core. An optical component pad provided for soldering an optical component selected from either a light emitting element or a light receiving element around a lens on the opposite side of the substrate having the electrical wiring, which is the same member; Light on the other side of the substrate with electrical wiring An electrical component pad provided for soldering an electrical component on the surface of the wiring layer is electrically connected to an optical component or an electrical component pad and an electrical wiring of a substrate having electrical wiring, and the optical wiring layer And an electrical wiring provided on the surface of the optical wiring layer on the opposite side of the substrate having electrical wiring, and an optical / electrical wiring board.
According to a fourth aspect of the present invention, the optical wiring layer intersects the core that propagates light in parallel with the layer, the cladding in which the core is buried, and the core with an inclination. a mirror which is formed, said cladding positioned on the light is focused on the mirror is reflected by the mirror has a lens to pass through the said core, Ru said lens said cladding same members der light A method of manufacturing an electrical wiring board, in which a recess is embedded on a support body that has been processed with a recess serving as a lens mold, and then a clad is formed on the support to have a predetermined thickness, and then a core And then forming a clad so as to embed the core, thereby forming an optical wiring layer provided with a lens, and using a dicing saw having a cutting edge of 90 ° with respect to the optical wiring layer , With a slope that changes the propagation direction to 90 ° Forming a cutting plane intersecting with the metal thin film on the cut surface, and forming a mirror surface, a step of peeling the optical wiring layer from the support, the optical wiring layer, having an electrical wiring and adhering via an adhesive layer on the electrical wiring side of the substrate, by a laser from the side with the lens of the optical wiring layer side, small-diameter hole for via hole penetrating the said adhesive layer and the optical wiring layer And at least a via hole penetrating the optical wiring layer and the adhesive layer, an optical component pad, and a metal layer electrically connecting the via hole and the optical component pad are formed by a semi-additive method. A process for producing an optical / electrical wiring board.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
1. Optical Wiring Layer FIG. 1 shows a cross-sectional view of a waveguide layer having a mirror and a lens in the optical / electrical wiring board of the present invention. The core 1 is an optical waveguide that is buried in the clad 2 and propagates laser light. Further, in the lens 3, the portion reflected by the mirror 4 is a distance close to the focal point. In other words, even when a horizontal misalignment occurs in a module such as a laser, light always passes through the waveguide, and the alignment becomes simple. Further, since the lens and the clad or the lens and the core are the same member and formed simultaneously, the alignment between the lens and the clad or the core is substantially unnecessary.
[0007]
The resin forming the clad preferably has a high glass transition temperature Tg, a high insulation resistance, and a low coefficient of thermal expansion. Examples of the film forming method include thermosetting and photocuring. For example, a polyimide resin or an epoxy resin is suitable.
[0008]
As for the properties of the resin forming the core, the glass transition temperature Tg is high, the insulation resistance is high, and the coefficient of thermal expansion is low, as is the case with the resin of the cladding layer. In addition, the refractive index of the cladding layer of the optical waveguide is larger. You need to choose one.
[0009]
2. Manufacturing Method of Optical Wiring Layer When the lens 3 in FIG. 1 is the same member as the cladding, a release film 6 is formed on a support 5 such as Si that has been processed into a lens mold in advance as shown in FIG. After that, a clad 7 is formed as shown in FIG. Next, after the core 8 is formed, it is processed into a core pattern by sputtering, photolithography or the like, and then the clad 9 is formed (FIG. 2 (c)). Subsequently, a mirror surface 11 is formed using a machine capable of fine processing such as a dicing saw 10 (FIG. 2 (d)). Finally, an optical wiring layer is obtained by peeling from a support such as Si (FIG. 2 (e)).
[0010]
When the lens 3 of FIG. 1 is the same member as the core, a release film 13 is formed on a support 12 such as Si that has been processed into a lens mold in advance as shown in FIG. A film is formed (FIG. 3 (b)). Next, only the cladding of the lens forming portion is pierced by an etching method such as RIE (FIG. 3 (c)). Thereafter, the core 15 is formed as shown in FIG. 3D, and the inside of the hole is filled with the core material. Then, after processing into a core pattern using sputtering or photolithography, a clad 16 is formed (FIG. 3 (e)). Subsequently, the mirror surface 17 is formed using a machine capable of fine processing such as a dicing saw having a 90 ° blade edge (FIG. 3 (f)). Finally, an optical wiring layer is obtained by peeling off from a support such as Si (FIG. 3 (g)).
[0011]
In the optical / electrical substrate of the present invention, in order to accurately align the light emission and light receiving portion of an optical element such as a laser or a photodiode on a lens, a substrate or a waveguide layer having electrical wiring using photolithography or the like It is also possible to attach a marker to the optical element, attach a marker to one optical element, and move both optical markers to a predetermined position by image recognition to fix both markers, or form bumps on the pads. A flip chip method may be used.
[0012]
The mirror may be left in a cut state, but a metal thin film may be attached by vapor deposition or the like in order to reduce the light that goes straight on the mirror portion that causes light loss. In order to maintain the mechanical strength, a space generated during processing may be filled with an appropriate resin.
[0013]
As a method for producing the concave portion of the support serving as the lens mold, for example, after forming a circular pattern by photolithography, it can be produced by using isotropic etching. Or it can also produce by cutting on a metal support body. As shown in FIG. 4, the concave shape of the support is shown in FIG. 4B or FIG. 4 (FIG. 4B) designed so that the convex portion of the lens is lower than the upper clad of the waveguide in order to protect the lens in the product. The shape of c) may be used. In these cases, the mask is first applied only to the lens on the support and the other parts are etched, and then the mask is applied to the part other than the concave part so that the lens part becomes a concave surface part. Isotropic etching may be performed.
[0014]
3. Optical / Electrical Wiring Board FIG. 5 (a) shows a cross-sectional view of the optical / electrical wiring board of the present invention passing through the center of the pad 27 and longitudinally cutting the core portion of the optical waveguide, and FIG. Shown in 5 (b).
[0015]
As shown in FIG. 5, the optical / electrical wiring board of the present invention has a structure in which an optical wiring layer (core 22, clad 20) is laminated on a substrate 18 having an electrical wiring 23 via an adhesive layer 19. . The substrate 18 may be a single-layer insulating substrate or a multilayer wiring substrate in which electrical wiring and insulating layers are alternately stacked. The constituent material may be an insulating substrate in which a glass cloth is impregnated with a resin, a polyimide film, a ceramic substrate, or a multilayer wiring substrate based on them.
[0016]
The optical wiring layer shown in FIG. 5 is formed with a lens 25 for increasing the positional deviation allowable range of the optical component and a mirror 26 that reflects the laser light as the optical signal and changes the propagation direction to 90 °.
[0017]
A pad 27 on which optical components such as a laser light emitting element and a light receiving element are mounted is disposed around the lens 25. This pad is formed on the optical wiring layer. Further, the optical component can be soldered to the optical / electrical wiring board of the present invention through a reflow furnace.
[0018]
The electrical component pads 27 are connected to the electrical wiring 23 via the electrical wiring 21 and the via holes 24 on the optical wiring.
[0019]
FIG. 6 is a cross-sectional view when the lead 30 of the laser light emitting element 29 such as a semiconductor laser is soldered on the pad 28. The laser beam 32 emitted from the laser emitting surface 31 of the laser emitting element 29 is reflected by the mirror 33 and propagates through the core 34. Even if the mounting position of the laser is shifted in the horizontal direction, the laser beam is focused on the core.
[0020]
FIG. 7 is a cross-sectional view when the lead 37 of the light receiving element 36 such as a photodiode is soldered on the pad 35. The laser beam 39 propagating through the core 38 is reflected by the mirror 40 and enters the light receiving surface 41 of the light receiving element 36. The spread of the laser beam is suppressed by the lens and guided to the receiving surface.
[0021]
A pad for soldering optical components may be provided on the optical wiring layer of the optical / electrical wiring board, or an electrical wiring may be provided. The pad for the electrical component may be electrically connected to the wiring on the substrate having the electrical wiring through the via hole in the same manner as the pad for the optical component.
[0022]
When the electrical wiring is provided on the optical wiring layer, the pad may be electrically connected only to the electrical wiring on the optical wiring layer and not to the electrical wiring on the substrate having the electrical wiring. May be. In this case, of course, there is no via hole for electrically connecting the pad and the electric wiring on the substrate.
[0023]
4). Manufacturing Method of Optical / Electrical Wiring Substrate The manufacturing method of the optical / electrical wiring substrate of the present invention is basically as follows. First, apart from a substrate having electrical wiring, an optical wiring layer is formed on a support. Next, it adheres to the substrate. Further, a via hole for electrically connecting the pad and the electric wiring on the substrate having the electric wiring is formed.
[0024]
Hereinafter, one embodiment will be described according to the flow of FIGS. 8A to 8D, focusing on the pads for optical components that are electrically connected to the electrical wiring on the substrate by via holes.
[0025]
The optical wiring layer 44 of the present invention is produced (FIG. 8 (a)). Next, as shown in FIG. 8B, an adhesive 43 is applied on the substrate 42 having the electrical wiring, and is adhered to the side having the mirror of the optical wiring layer 44. The optical wiring layer at this time may be bonded to a substrate having electrical wiring after being formed into a film, or may be peeled off from the support after being bonded to a substrate having electrical wiring in a state with a support (see FIG. Not shown).
[0026]
As shown in FIG. 8C, a small-diameter hole 45 for a via hole is opened by a laser. In this case, the electrical wiring 46 serves as a stopper during laser processing.
[0027]
By the semi-additive method, a metal layer is formed in the via hole 47 and in a portion connecting the pad 48 and the via hole, and the optical / electrical wiring board of the present invention is obtained as shown in FIG. If necessary, pads for electrical components (not shown), via holes (not shown) for electrically connecting the electrical pads and electrical wiring (not shown), or electrical wiring (not shown) can be formed at the same time.
[0028]
5. An optical component (laser, photodiode) and an electrical component are mounted on a mounting substrate optical / electrical wiring substrate. Solder and reflow techniques are preferably used for mounting. By using optical wiring for the high-speed signal portion and electrical wiring for the other portions, it is possible to construct a circuit that operates at high speed and suppresses the generation of electromagnetic waves.
[0029]
【The invention's effect】
The present invention has the following effects.
[0030]
First, since the lens is provided, the optical axis alignment between the light emitting element and the optical wiring layer is simple. Further, since the lens and the core, or the lens and the clad are the same member, their alignment is substantially unnecessary.
[0031]
Secondly, since the support is peeled off after processing, a support made of Si or the like having a lens shape once manufactured can be used repeatedly, and a product can be manufactured at a lower cost than in the past.
[0032]
Third, since the optical wiring layer is provided on the substrate having the electric wiring, there is an effect that high-density mounting or miniaturization is possible.
[0033]
Fourth, an optical wiring layer is formed on a support separately from a substrate having electrical wiring, and the optical wiring layer is bonded to the substrate having electrical wiring. Compared with the case where the optical wiring layer is directly installed on the substrate, the influence of the unevenness of the electric wiring on the substrate having the electric wiring can be reduced. Accordingly, there is an effect that the propagation loss of the optical signal in the optical wiring layer can be reduced.
[0034]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an optical wiring layer of the present invention.
FIG. 2 is a cross-sectional view showing an example of a method for manufacturing an optical wiring according to the present invention.
FIG. 3 is a cross-sectional view showing another example of the method for producing an optical wiring layer of the present invention.
FIG. 4 is an explanatory diagram showing the shape of a support that serves as a matrix for producing a lens.
FIGS. 5A and 5B are a cross-sectional view (a) and a plan view (b) in which an optical wiring layer is vertically cut in a portion where an optical component is mounted on an optical / electrical wiring board of the present invention.
FIG. 6 is a cross-sectional view of the propagation of laser light on an optical / electrical mounting board in which a laser light emitting element is mounted on the optical / electrical wiring board of the present invention.
FIG. 7 is a cross-sectional view of the propagation of laser light on an optical / electrical mounting board in which a light receiving element is mounted on the optical / electrical wiring board of the present invention.
FIG. 8 is a cross-sectional view showing an example of a method for manufacturing an optical / electrical wiring board according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Core 2 ... Cladding 3 ... Lens 4 ... Mirror 5 ... Support body 6 ... Release film 7 ... Cladding 8 ... Core 9 ... Cladding 10 ... Dicing saw 11 ... Mirror surface 12 ... Supporting body 13 ... Release film 14 ... Cladding 15 ... Core 16 ... Clad 17 ... Mirror surface 18 ... Substrate 19 ... Adhesive layer 20 ... Clad 21 ... Electric wiring 22 on optical wiring ... Core 23 ... Electric wiring 24 ... Via hole 25 ... Lens 26 ... Mirror 27 ... Pad 28 ... Pad 29 ... Laser light emitting element 30 ... Lead 31 ... Laser light emitting surface 32 ... Laser light 33 ... Mirror 34 ... Core 35 ... Pad 36 ... Light receiving element 37 ... Lead 38 ... Core 39 ... Laser light 40 ... Mirror 41 ... Light receiving surface 42 ... Electric wiring Substrate 43 having adhesive 44 Optical wiring layer 45 Small hole 46 for via hole Electric wiring 47 Via hole 48 Pad

Claims (5)

An optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer ,
The optical wiring layer includes a core for propagating light parallel to the layer,
A cladding in which the core is buried;
Using a dicing saw having a cutting edge of 90 ° relative to the core, a mirror formed to intersect with an inclination that changes the propagation direction to 90 °, and attached with a metal thin film using vapor deposition,
A lens located on the cladding and reflected by the mirror and reflected by the mirror to pass through the core; and the lens is the same member as the cladding,
An optical component pad provided for soldering an optical component selected from either a light emitting element or a light receiving element around a lens on the opposite side of the substrate having electrical wiring;
Electrically connecting the optical component pads and the electrical wiring of the substrate having electrical wiring, and via holes penetrating the optical wiring layer and the adhesive layer ;
An optical / electrical wiring board comprising: An optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer ,
The optical wiring layer includes a core for propagating light parallel to the layer,
A cladding in which the core is buried;
Using a dicing saw having a cutting edge of 90 ° relative to the core, a mirror formed to intersect with an inclination that changes the propagation direction to 90 °, and attached with a metal thin film using vapor deposition,
A lens located on the cladding and reflected by the mirror and reflected by the mirror to pass through the core; and the lens is the same member as the cladding,
An optical component pad provided for soldering an optical component selected from either a light emitting element or a light receiving element around a lens on the opposite side of the substrate having electrical wiring;
On the surface of the optical wiring layer on the opposite side of the substrate having electrical wiring, pads for electrical components provided for soldering electrical components;
A via hole penetrating the optical wiring layer and the adhesive layer, electrically connecting an optical component or electrical component pad and an electrical wiring of a substrate having an electrical wiring;
An optical / electrical wiring board comprising: An optical / electrical wiring board in which an optical wiring layer is bonded to a substrate having electric wiring via an adhesive layer ,
The optical wiring layer includes a core for propagating light parallel to the layer,
A cladding in which the core is buried;
Using a dicing saw having a cutting edge of 90 ° relative to the core, a mirror formed to intersect with an inclination that changes the propagation direction to 90 °, and attached with a metal thin film using vapor deposition,
A lens located on the cladding and reflected by the mirror and reflected by the mirror to pass through the core; and the lens is the same member as the cladding,
An optical component pad provided for soldering an optical component selected from either a light emitting element or a light receiving element around a lens on the opposite side of the substrate having electrical wiring;
On the surface of the optical wiring layer on the opposite side of the substrate having electrical wiring, pads for electrical components provided for soldering electrical components;
A via hole penetrating the optical wiring layer and the adhesive layer, electrically connecting an optical component or electrical component pad and an electrical wiring of a substrate having an electrical wiring;
Electrical wiring provided on the surface of the optical wiring layer on the opposite side of the substrate having electrical wiring;
An optical / electrical wiring board comprising: An optical wiring layer includes a core for propagating light parallel to the layer, a cladding in which the core is buried, a mirror formed so as to intersect with the core at an inclination, and on the cladding position and light is focused on the mirror is reflected by the mirror to have a lens that pass through within the core, there said lens in said cladding the same members der Ru optical-electrical wiring board manufacturing method of And
On a support subjected to mold and processing of the recesses consisting of a lens, the formed cladding to have a predetermined thickness on the embedding further support recess, then to form a core and then to fill the core Forming an optical wiring layer having a lens by forming a cladding; and
A dicing saw having a cutting edge of 90 ° with respect to the optical wiring layer is used to form an intersecting cut surface having an inclination that changes the propagation direction to 90 °, and a metal thin film is attached to the cut surface, and a mirror Forming a surface ;
A step of peeling the optical wiring layer from the support,
Bonding the optical wiring layer to the electric wiring side of the substrate having electric wiring via an adhesive layer ;
Forming a small-diameter hole for a via hole penetrating the optical wiring layer and the adhesive layer with a laser from a surface side including the lens on the optical wiring layer side ;
Forming at least a via hole penetrating the optical wiring layer and the adhesive layer, an optical component pad, and a metal layer electrically connecting the via hole and the optical component pad by a semi-additive method. A method of manufacturing an optical / electrical wiring board.   A mounting board comprising an optical component and / or an electrical component mounted on the optical / electrical wiring board according to claim 1.

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