JP2005201937A - Optical waveguide array and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide array which has such a structure that the size of cross-section of a light guide, for example, a core in a light incident end surface and a pitch between the light incident end surfaces adjacent to each other is not limited by a pitch between light waveguides and permits the high density integration based on the narrow-pitch formation between the light waveguides, and to provide a manufacturing method capable of mass-production of the optical waveguide array at a high yield and at a low cost. <P>SOLUTION: In the optical waveguide array 10A, a plurality of optical waveguides 2 are juxtaposed, the light incident end surface 3 and a light outgoing end surface 4 are formed on both ends of the optical waveguides 2 as 45° inclined reflective surfaces and a light emitting element 5 and a light receiving element 7 are respectively arranged oppositely to them. Therein, both ends of respective optical waveguides 2 are shifted and arranged in the length direction, the optical guides 2a, 2b of which the waveguiding directions of light are reverse to each other are alternately arranged and, by utilizing a space resultantly formed, the width of the light waveguides (light guide) 2 of a light incident part 9 is enlarged toward the light incident end surface 3. The optical waveguide array is manufactured by injection molding etc. using a die. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical information processing apparatus, for example, an optical waveguide array used for optical wiring between semiconductor chips, and a manufacturing method thereof.

  Conventionally, all signal transmission between semiconductor chips such as LSI (Large Scale Integrated Circuit) has been performed by electric signals via substrate wiring. However, with the recent increase in functionality of MPU (Microprocessor Unit), the amount of data exchanged between chips has increased remarkably, making it necessary to increase the speed of signals and increase the density of signal wiring. As a result, various high frequency problems have emerged. Typical of these are EMC / EMI (Electro-Magnetic Compatibility / Interference) such as signal delay due to wiring resistance and capacitance, impedance mismatch, or noise and crosstalk. For example, compatibility with the electromagnetic environment). In order to solve such problems, various methods such as optimization of wiring arrangement and development of new materials have been developed.

  However, the effects of optimizing the wiring layout and developing new materials are also hampered by physical limitations, and a mounting board that assumes the mounting of a simple semiconductor chip is necessary to achieve higher system functionality. It is necessary to review the structure itself. Therefore, in order to solve these problems, for example, fine wiring bonding by making a multichip module (MCM), electric wiring bonding by sealing and integrating various two-dimensional semiconductor chips using polyimide resin, etc. Developments such as three-dimensional bonding of semiconductor chips by combination have been made.

  Fine wiring bonding by MCM realizes fine wiring bonding that cannot be formed on a conventional mother board (multilayer printed circuit board) by mounting a high-performance chip on a precision mounting board such as ceramic or silicon. As a result, the pitch of the wiring can be reduced, and the amount of data exchange can be dramatically increased by widening the bus width.

  For electrical wiring coupling by chip sealing / integration, various semiconductor chips and the like are two-dimensionally sealed / integrated using polyimide resin or the like, and fine wiring coupling is performed on the integrated substrate. As a result, the pitch of the wiring can be reduced, and the amount of data exchange can be dramatically increased by widening the bus width.

  The three-dimensional bonding of the semiconductor chips by bonding the substrates is a laminated structure in which through electrodes are provided in various chips and bonded to each other. This shortens the connection between different chips and avoids problems such as signal delay. However, new problems such as an increase in the amount of heat generated due to lamination and thermal stress between chips arise.

  Furthermore, as a technique for realizing fundamentally high speed and large capacity of signal transmission / reception, an optical signal transmission coupling technique using optical wiring as shown in FIG. 21 has been developed (for example, see Non-Patent Document 1 described later). .) This technology converts an electrical signal into an optical signal and greatly improves the transmission speed between chips. In addition, the optical signal does not require any countermeasure for electromagnetic waves, and a relatively free wiring design is possible. However, since new problems such as time loss and optical element cost due to conversion arise, this countermeasure becomes important. Hereinafter, in the present specification, when the light emitting element and the light receiving element are not distinguished, they may be referred to as optical elements.

  Various optical wiring techniques corresponding to signal transmission between chips have been proposed, for example, an active interposer system (see Non-Patent Document 1, p. 125, described later, FIG. 7), free space transmission. System (see p.123 of Non-Patent Document 1 described later, see FIG. 5), optical connector connection system (see p.122 of Non-Patent Document 1 described later, see FIG. 4), optical waveguide embedding method (non-patent document described later) P.124 of Document 1, see FIG. 6), and an optical waveguide surface mounting method (see Non-Patent Document 2 described later).

  In the active interposer system, an optical waveguide is mounted on a board, optical fiber connectors are attached to the incident side end and the emission side end of the optical waveguide, and transmission between the boards is performed by an optical fiber. The optical element is mounted on the back surface of the transceiver module and precisely positioned with respect to the 45 ° total reflection mirror of the waveguide.

  The advantage of this method is that it can be deployed on an existing board system, and because it uses an optical fiber, it can be widely applied both inside and outside the board. However, because the structure is large, the cost is high, it is difficult to align the optical axis, the electrical transmission path is difficult to shorten, and it is not suitable for high-frequency transmission, and an optical fiber is used as the transmission medium. The problem is that there is a limit to the number of buses.

  In the free space transmission system, an optical wiring board (quartz) is mounted on the back surface of the board as an optical transmission path, and light is reflected in a zigzag manner in the optical wiring board to propagate signals. In order to facilitate alignment of the optical axis, a hybrid optical system in which several lenses are combined is configured.

  The advantage of this method is that, in principle, multi-channels (multiplex transmission) of several thousand levels are possible by optical element array and free space transmission, and the optical axis alignment is possible because of the hybrid optical system. It is easy. However, there are problems that the optical wiring board (quartz) is expensive and that the signal propagation due to reflection tends to disturb the waveform and increase the propagation loss. In addition, since many newly developed technologies are incorporated, there is also a problem that there is almost no track record regarding reliability.

  In the optical connector connection method, a small optical fiber connector is attached around an LSI chip, transmission between LSI chips is performed by an optical fiber, and an optical transmission module system in which an optical path can be freely set after LSI mounting is configured.

  The advantage of this method is that the optical connector and the optical path are guaranteed to be coupled with an optical connector, which eliminates the need for a costly optical axis alignment process and uses an optical fiber. Transmission is possible, and it can be deployed on an existing board system. However, there is a limit to miniaturization of the optical connector module, and it is difficult to shorten the electrical wiring between the LSI chip and the optical connector. Therefore, it is not suitable for high-frequency transmission, and an optical fiber is used as a transmission medium. Since it is adopted, there are problems in that there is a limit to the number of buses and that there are many components and it is difficult to reduce the cost per bus.

  The optical waveguide embedding method is a method in which an optical element is directly attached to the back surface of an LSI, an optical waveguide is embedded in a printed board, and optical wiring is provided while maintaining the form of an existing board system. Further, by adopting a microlens for coupling the optical element and the optical path, the allowable amount of optical axis deviation is relaxed to the general mounting accuracy level.

  The advantage of this method is that the optical element is directly mounted on the back surface (electrode formation surface) of the LSI chip, so that the electrical wiring path between the LSI chip and the optical element can be shortened to the limit, and collimated optical coupling is generally used. The optical axis can be aligned with mounting accuracy. However, since the optical wiring is provided in the printed circuit board, it is difficult to manufacture and reduce the cost of the board, the heat dissipation measures for the optical elements are unknown, and the printed circuit board is fragile. The problem is that the optical coupling loss between the two may vary.

  In the optical waveguide surface mounting method, the optical element is fixed to the back surface of the LSI chip as in the optical wiring system based on the first embodiment of the present invention shown in FIGS. Is mounted on the surface of a printed circuit board, and optical wiring is provided side by side while maintaining the existing board structure as it is. Further, by adopting a microlens for coupling the optical element and the optical path, the allowable amount of optical axis deviation is relaxed to the general mounting accuracy level.

  The advantage of this method is that the optical element is directly mounted on the back surface (electrode formation surface) of the LSI chip, so that the electrical wiring path between the LSI chip and the optical element can be shortened to the limit, and collimated optical coupling is generally used. The optical axis can be aligned with mounting accuracy. In addition, since the structure is simple, the cost can be reduced and there is an advantage that it can be deployed on an existing board system. However, there are some concerns, such as the fact that the optical element is directly attached to the LSI chip, it is necessary to develop a dedicated LSI, and the optical element may be deteriorated due to the heat of the high-temperature LSI chip.

  Regarding optical transmission between LSI chips, the surface mounting method described last is considered to be the most appropriate method among the above five methods. There are five reasons for this.

  First, the existing board system can be used as it is. If the board structure cultivated so far is changed, inconveniences that require enormous efforts for confirming performance, reliability and high frequency performance occur. Therefore, a structure in which an existing board cannot be used, such as an optical waveguide embedded board, is not desirable.

  Secondly, the existing mounting process can be used as it is. That is, materials and components that take into consideration high-temperature processes after mounting optical elements such as solder reflow and underfill resin sealing should be adopted.

  Third, it is a structure that eliminates a large-scale structure as much as possible. This is because the board rigidity is generally low, and if a large part is provided, the optical path structure is deformed by an external stress, and an optical axis shift is likely to occur. Therefore, the method of providing the transceiver module shown in FIG. 21 with a metal post structure should be avoided.

  Fourth, it is an optical wiring structure that can be densified. That is, when specializing in inter-chip optical wiring on a board, it is considered that an optical fiber that cannot be densified should not be adopted. The optical connector connection method using an optical fiber should be considered as a system suitable for inter-board communication.

  Fifth, the wiring length between the LSI chip and the optical element can be shortened. That is, in the structure in which the electrical wiring between the LSI chip and the optical element cannot be shortened, the high-frequency electrical signal deteriorates before reaching the optical element, and the effect of converting the electrical signal into an optical signal is lost. Therefore, it is necessary to adopt a method that can shorten the electric wiring distance.

  FIG. 22 shows a general configuration when the first semiconductor chip 31 and the second semiconductor chip 32 are coupled by optical wiring using the optical waveguide array 10E in the optical waveguide surface mounting method shown in FIG. Is shown. 22A is a plan view seen from the printed wiring board 33 side, and FIG. 22B is a cross-sectional view taken along the line EE shown in FIG. FIG. 4B is a plan view showing the positional relationship between the light emitting element array 6E and the light receiving element array 8E and the positions of the light emitting element 5 and the light receiving element 7 on the substrate of these arrays. In FIG. 22 (b), the top and bottom of FIG. 22 (a) are inverted in accordance with the orientation of FIG. In FIG. 22A, an optical waveguide array corresponding to input / output of 6 channels is shown, but this number is for the convenience of drawing and the number of channels is not particularly limited.

  In the optical waveguide array 10E, as shown in FIG. 22 (a), a plurality of optical waveguides 2 are juxtaposed in the width direction, and as shown in FIG. 22 (b), each optical waveguide 2 has light incident end faces at both ends. 3 and the light emitting end face 4 are formed as 45-degree inclined reflection surfaces, and a light emitting element 5 and a light receiving element 7 are respectively arranged to face these inclined reflection surfaces.

  The operation will be described as follows. The electrical signal output from the first semiconductor chip 31 is converted into an optical signal by an attached circuit (not shown) and the light emitting element 5. The optical signal from the light emitting element 5 is incident on the 45-degree inclined reflection surface of the light incident end face 3, is totally reflected here, proceeds in the optical waveguide 2 a to the light emission end face side, and the 45-degree inclined reflection of the light emission end face 4. The light is totally reflected again by the surface and is received by the light receiving element 7 provided facing the surface. The optical signal is converted into an electric signal by the light receiving element 7 and transmitted to the second semiconductor chip as an electric signal. In this way, one light emitting element 5, one optical waveguide 2, and one light receiving element 7 form one set to form one signal transmission path.

  In the optical waveguide array 10E, a plurality of (in the figure, 12) optical waveguides 2 are juxtaposed in the width direction to form a signal transmission path array. At that time, both end faces of all the optical waveguides 2 are arranged in a straight line. As a result, on the semiconductor chips 31 and 32, all the light emitting elements 5 and the light receiving elements 7 are arranged in a straight line. Is done.

  Furthermore, as shown in FIG. 22 (c), the light emitting element 5 and the light receiving element 7 are respectively provided with a light emitting element array 6E in which the light emitting elements 5 are provided adjacent to each other, and a light receiving element 7 in the adjacent directions. The light receiving element array 8E is arranged. As a result, the optical waveguide array is also divided into two regions. In the upper half region of the figure, an optical signal is transmitted from the first semiconductor chip 31 toward the second semiconductor chip 32. Only the optical waveguide 2a is disposed, and only the second optical waveguide 2b in which an optical signal is transmitted from the second semiconductor chip 32 toward the first semiconductor chip 31 is disposed in the lower half region.

  The above structure inevitably arises from the necessity in the manufacturing process of the optical waveguide array and the necessity in the manufacturing process of the light emitting element and the light receiving element that are installed opposite to the light incident part and the light emitting part. This is the structure, which currently makes it difficult to integrate optical waveguides with high density. Hereinafter, the reason why the above structure is formed and the resulting disadvantages will be described.

  In the manufacturing process of the optical waveguide array, after forming the optical waveguide array, a 45-degree inclined reflective surface is formed at the end as the light incident end surface and the light output end surface. As shown in FIG. 23A, the 45-degree inclined reflecting surface is usually formed by mechanical processing such as cutting with a disc blade saw having a V-shaped blade (see Non-Patent Document 3 described later). . In this mechanical processing, adjacent optical waveguides are continuously processed without being distinguished from each other, so that the 45-degree inclined reflecting surfaces of these optical waveguides are formed at adjacent positions. Usually, as shown in FIG. 23 (b), since the processing is performed while moving the disc blade saw in the direction orthogonal to the length direction of the optical waveguide, the 45-degree inclined reflection surface is one orthogonal to the optical waveguide. The distance between the 45-degree inclined reflecting surfaces coincides with the pitch between the optical waveguides.

  As described above with reference to FIG. 22B, the light-emitting element 5 that sends light to the optical waveguide 2 and the light-receiving element 7 that receives light from the optical waveguide 2 are respectively the light incident end face 3 and the light emitting end face 4. It is necessary to arrange it close to the position opposite to. Therefore, when the inclined reflecting surfaces are formed in a line on a straight line, the light emitting elements and the light receiving elements must also be arranged in a line at the same pitch as the distance between the inclined reflecting surfaces.

  On the other hand, according to the current semiconductor manufacturing technology, it is not preferable to mix the light emitting element 5 and the light receiving element 7 having different characteristics on the same substrate. Therefore, as a method of arranging a large number of the light emitting elements 5 and the light receiving elements 7 on a semiconductor chip or the like, a light emitting element array 6E in which the light emitting elements 5 are arranged in a line is formed on one substrate, and light receiving is also performed. It is preferable to form a light receiving element array 8E in which the elements 7 are arranged in a row on another substrate and fix these substrates so that the light emitting elements 5 and the light receiving elements 7 are arranged in a row.

  At this time, since these substrates are also processed into a straight line by mechanical processing such as dicing, a structure in which two types of substrates need to be intermingled, for example, light emitting elements and light receiving elements are alternately arranged on a straight line. A structure cannot be formed. It can be formed only in a structure in which several light emitting element arrays 6E and light receiving element arrays 8E are arranged in a line. The simplest example is the structure shown in FIG.

  In this way, the inclined reflecting surfaces are formed in a straight line, and accordingly, the light emitting elements 5 are arranged in a state of the light emitting element array 6E in which the light emitting elements 5 are adjacent to each other and formed in a line. 22A and 22C is inevitably formed by using the inclined reflecting surfaces arranged in a straight line so as to face each other as the light incident end surface 3. By taking this structure, the following inconvenience occurs.

  First, the light incident end face 3 is desired to be devised in size, shape, etc. in order to efficiently and stably capture an optical signal from the light emitting element 5, but the light incident end faces 3 are adjacent to each other. When arranged in a line in the width direction of the optical waveguide, there is no room for such a space, and the width of the light incident end face 3 is limited to less than the size of the pitch between the optical waveguides. is there. For this reason, in order to ensure the width of the light incident end face 3, the pitch between the optical waveguides is limited, which limits the high density integration of the optical waveguide array.

  Second, the light emitting element 5 limits the high density integration of the optical waveguide array. The optical waveguide itself can be formed with a pitch of 10 μm, for example, with a width of 5 μm, and there is no great technical difficulty in forming a narrow pitch. On the other hand, when the light emitting element 5 uses, for example, a VCSEL (Vertical Cavity Surface-Emitting Laser), the light interference between adjacent light emitting elements 5 and the adverse effect of crosstalk due to element heat generation are avoided. Therefore, the distance between the light emitting elements 5 cannot be made smaller than 100 μm. Here, the optical interference means that the light travels with a spread of about 10 °, so that it interferes with the adjacent optical signal transmission line, and the crosstalk due to the element heat generation means the heat generated by the element. It is transmitted to an adjacent element, and the characteristic of the adjacent element changes due to this heat.

  In the structure described above, since the light emitting elements 5 are arranged in a line in the width direction of the optical waveguide, the arrangement pitch of the light emitting elements 5 is directly the arrangement pitch between the optical waveguides. For this reason, in order to ensure 100 μm as the arrangement pitch of the light emitting elements 5, it becomes impossible to arrange the optical waveguides at a pitch of 100 μm or less to form a high-density array. As a result, at present, the number of optical transmission channels between semiconductor chips by the optical waveguide surface mounting method is only tens of channels, which is insufficient.

  Thirdly, an electrical wiring distance for connecting the input / output pads of the semiconductor chip to the light emitting element 5 and the light receiving element 7 becomes long, and it becomes difficult to take measures against high frequency.

  As shown in FIG. 22 (c), for example, in a terminal arrangement of a semiconductor chip such as the semiconductor chip 31, in general, the input pad 37 and the output pad 38 connected to a specific circuit are often arranged close to each other. . On the other hand, the arrangement of the optical elements is largely divided into two regions of the light emitting element array 6E and the light receiving element array 8E, and the light emitting element 5 and the light receiving element 7 connected to a specific circuit are arranged far apart. In FIG. 22C, since several tens to several hundreds of optical elements are actually arranged, the light emitting element 5 and the light receiving element 7 connected to a specific circuit are arranged far apart. Become). Therefore, inevitably, one or both of the electric wiring 39E connecting the input pad and the light receiving element 7 and / or the electric wiring 40E connecting the output pad and the light emitting element 5 become long, and it is difficult to take measures against high frequency.

  A method of selectively forming the inclined reflection surface of the optical waveguide array for each optical waveguide by means of isotropic etching or the like has also been studied, but accuracy and certainty are insufficient, and isotropic etching is currently performed. For example, it is considered that forming an inclined reflecting surface for each optical waveguide by mass production is impossible.

Nikkei Electronics, “Encounter with Optical Wiring”, December 3, 2001, p.122-125, Fig.4-7 Yasuhiro Ando, “Trends in Optical Interconnection Technology and Next-Generation Device Mounting Technology”, NTT R & D, Vol.48, No.3, p.271-280 (1999) IEICE Transactions C, Vol.J84-C, No.9, p.745-755, September 2001

  The present invention has been made in view of such a situation, and an object of the present invention is to determine the size of the cross section of the light guide path (for example, the core) at the light incident end face and the distance between the adjacent light incident end faces between the optical waveguides. To provide an optical waveguide array having a structure that is not limited by the pitch and enabling high-density integration by narrowing the pitch of the optical waveguide array, and a manufacturing method capable of mass-producing the optical waveguide array with a high yield and low cost. is there.

The present invention relates to an optical waveguide array in which a plurality of optical waveguides having a light guide that guides light from a light incident part to a light emitting part are juxtaposed.
On one side, the light incident portions of the optical waveguides adjacent to each other among the plurality of optical waveguides, or the light incident portion and the light emitting portion are arranged at positions shifted from each other,
In at least one of the light incident portions of these optical waveguides, a cross section of the light guide path is enlarged toward the light incident end face, and the present invention relates to an optical waveguide array.

  In addition, the method for manufacturing the optical waveguide array includes: a step of manufacturing a mold having a shape corresponding to the light guide path; and a step of forming the light guide path using the mold. It is also related to the method.

  In general, when a plurality of elongated linear or rod-like objects having the same length, such as an optical waveguide, are gathered with their ends aligned and without a gap, an aggregate in which the objects are gathered most closely is obtained. Also in the optical waveguide array, it is desirable to make an assembly having such a structure in order to increase the mounting density of the optical waveguide. For example, a surface in which a large number of optical waveguides are juxtaposed in the width direction as shown in FIG. An optical waveguide array or the like is used.

  However, if both ends are completely aligned, there is no gap, that is, a region not occupied by the optical waveguide, or in other words, there is no space region that can be used for any purpose. It becomes impossible to enlarge the width of the light guide. This is as described above with reference to FIG.

  On the contrary, when a slight shift is provided in the arrangement of the optical waveguides in the optical waveguide array, a gap region, that is, a space area that is not occupied by the optical waveguide and that can be used for some purpose is generated. For example, if the optical waveguide is slightly shifted in the length direction, a gap can be formed only at both ends of the optical waveguide array, and the light incident portion is transmitted to the optical signal without reducing the mounting density of the optical waveguide array. It is possible to create a space area that can be used to efficiently and reliably capture the shape.

  The present invention is based on the above general consideration, and according to the optical waveguide array of the present invention, on one side, the light incident portions of the optical waveguides adjacent to each other among the plurality of optical waveguides, or the light incident Since the part and the light emitting part are arranged at positions shifted from each other, there is a space region around the light incident part where the adjacent optical waveguide or the light incident part or the light emitting part is not arranged, Using this region, the light incident part is formed so that a cross section of the light guide path is enlarged toward the light incident end face in the light incident part. Since the cross section of the light guide path at the light incident end surface is enlarged, the efficiency and certainty that light from a light source is taken into the light guide path can be increased. In addition, the amount of light loss due to the deviation of the optical axis is reduced, and the tolerance of positioning error between the light source and the light incident portion is increased. Therefore, the alignment between the light source and the optical waveguide array is facilitated, and reliability is improved. In addition, the yield and mass productivity can be improved and the cost can be reduced.

  Also, as shown in FIG. 22, when the light incident part is formed at a position aligned with the light incident part of the adjacent optical waveguide, the distance between these light incident end faces is the same as the pitch between the optical waveguides. However, in the optical waveguide array of the present invention, these light incident portions are formed at positions shifted from each other. By increasing the amount of the shift, the distance between the light incident end faces is limited to the pitch between the optical waveguides. It can be enlarged without being. Thereby, the distance between the light emitting elements installed facing these light incident end faces can be increased, and light interference and crosstalk between the light emitting elements can be suppressed.

  As described above, in the optical waveguide array of the present invention, the size of the cross section of the light guide path (for example, the core) at the light incident end face and the distance between adjacent light incident end faces are limited by the pitch between the optical waveguides. Therefore, it is possible to proceed with the high density integration of the optical waveguide array by reducing the pitch of the optical waveguide array without worrying about the influence on them.

  According to the method for manufacturing an optical waveguide array of the present invention, since the method includes a step of producing a mold having a shape corresponding to the light guide and a step of forming the light guide using the die, the process is complicated. The optical waveguide array having the end shape can be mass-produced with a high yield, and the manufacturing cost can be reduced.

  The light incident on the optical waveguide array of the present invention is not particularly limited, and examples thereof include laser light from a semiconductor laser element or the like.

  In the optical waveguide array of the present invention, it is preferable that the cross section is enlarged by increasing the width of the light guide path. As a method of enlarging the cross section, the height of the light guide path may be increased. However, it is easier in manufacturing to increase the width of the cross section. At this time, the method of increasing the width is not particularly limited. However, if the width is linearly enlarged, the inclination of the side surface of the light guide is constant with respect to the light traveling direction. It is preferable because loss is hardly caused.

  In addition, in the length direction of the adjacent optical waveguides, it is preferable that the positions of the light incident portions or the positions of the light incident portion and the light emitting portion are shifted. As described above, when the optical waveguide is slightly shifted in the length direction, a gap can be formed only at both ends of the optical waveguide array without reducing the mounting density of the optical waveguide array, and the light incident portion Can be used.

  Furthermore, by increasing the displacement in the length direction, the distance between the light incident end faces can be increased without being limited by the pitch between the optical waveguides. Thereby, the distance between the light emitting elements installed facing these light incident end faces can be increased, and light interference and crosstalk between the light emitting elements can be suppressed.

  The adjacent optical waveguides may guide light in the opposite direction. In this way, at the end of the optical waveguide array, the light incident portions and the light output portions are alternately arranged in the width direction of the optical waveguide. As a result, there is an advantage that the distance between the light incident portions is increased and the space near the light emitting portion can be used. When the alternate arrangement of the light incident part and the light emitting part is adopted as in this example, the space available for the light incident part becomes larger than when only the light incident parts are arranged adjacent to each other. .

  In addition, the light incident end surface has an inclined reflection surface, and the incident light from the light source is reflected by the inclined reflection surface and then travels through the light guide path toward the light emitting portion. Is good. In this way, the light source can be arranged at a position facing the bottom surface rather than in the length direction of the optical waveguide array, and the light from the light source is directed to the light incident end surface of the adjacent optical waveguide. The light can enter the inclined reflecting surface without being obstructed.

  The cross-sectional shape of the light guide path may be a trapezoid. Accordingly, even if the light guide having a relatively large aspect ratio is formed by injection molding or stamping molding using the mold, the mold can be easily released, and the light guide is ejected. It can be produced by molding or stamping. Thereby, the manufacturing cost of the optical waveguide array can be reduced.

  Further, it is preferable that the optical waveguide is a joined body of a core and a clad. In this case, the core corresponds to the light guide path. The clad may be provided independently for each of the cores, or may be provided integrally with a plurality of the cores. Further, a part or all of the cladding may be omitted and replaced with an air layer or a substrate.

  The optical waveguide array may be made of a polymer material. This is because the use of a polymer material as the material of the optical waveguide makes it possible to produce the light guide, for example, the core, by injection molding or stamping, and the optical waveguide is compared with the case where a conventional quartz optical waveguide is used. This is because the manufacturing process of the waveguide array can be simplified. Thus, it becomes possible to produce an optical waveguide with an inexpensive equipment investment and a low manufacturing cost, which is advantageous as a cladding material.

The method of manufacturing the optical waveguide array of the present invention includes:
Forming a photosensitive resin layer on the substrate;
Exposing the photosensitive resin layer with synchrotron radiation using a mask having a predetermined pattern;
A developing step for removing the exposed portion of the photosensitive resin layer;
Depositing metal on the removed portion of the photosensitive resin layer;
Removing a non-photosensitive portion of the photosensitive resin layer to form a master mold which is a light guide mold;
Transferring a concavo-convex shape from the master mold to form a mother mold corresponding to the master mold;
Transferring the concavo-convex shape from the mother mold, and forming the constituent material of the light guide into the shape of the light guide array,
The method of exposing the photosensitive resin layer using the mask includes a step of exposing the photosensitive resin layer by irradiating the synchrotron radiation at an angle inclined with respect to the photosensitive resin layer. It is good to be.

  According to the method for manufacturing an optical waveguide array of the present invention, the constituent material of the light guide is formed into the shape of the light guide array using the mold. In the manufacturing method described above, the photosensitive resin layer is exposed to synchrotron radiation and developed to produce a prototype of the mold. At this time, since the inclined reflection surface is produced by irradiating the synchrotron radiation from an oblique direction using the mask, the inclined reflection surface is changed for each waveguide by changing the position of the end of the mask opening. The process of providing the desired position at a desired position can be performed by batch processing, which is efficient. Such processing is impossible with conventional machining.

  The synchrotron radiation is light having a higher energy than, for example, laser light, can completely expose the photosensitive resin layer having a thickness of about 10 μm, and has an inclined surface corresponding to the inclined reflection surface. The opening can be formed in the photosensitive resin layer with high accuracy. In addition, when it exposes using another light source, the said photosensitive resin layer with a thickness of 10 micrometers cannot penetrate and it cannot expose completely.

  Next, a preferred embodiment of the present invention will be described specifically and in detail with reference to the drawings.

Embodiment 1
FIG. 3 shows a first case where the first semiconductor chip 31 and the second semiconductor chip 32 are coupled by the optical wiring using the optical waveguide array 10A according to the first embodiment by the optical waveguide surface mounting method. 2 is a perspective view showing a mounting state in the vicinity of a semiconductor chip 31. FIG. As shown in FIG. 3, the first semiconductor chip 31 is, for example, a wafer level CSP (Chip Scale Package), and a back surface (electrode formation surface) of a mounting substrate 33 such as a printed wiring board via a solder bump 35 or the like. Implemented above. The back surface (electrode forming surface) of the semiconductor chip 31 and the mounting substrate 33 are sealed with a mold resin 36.

  The light emitting element array 6 </ b> A and the light receiving element array 8 </ b> A are fixed to the back surface of the first semiconductor chip 31. Further, the optical waveguide array 10A is fixed on the mounting substrate 33 so that the light incident portion and the light emitting portion of the optical waveguide array 10A face these optical elements, and the board structure of the existing electric wiring is maintained as it is. However, an optical wiring is also provided.

  FIG. 4 is a plan view of the main part of the optical wiring system as viewed from the back side of the first semiconductor chip 31. Although FIG. 4 shows an optical waveguide array corresponding to 15 channels of input / output, this number is for the convenience of drawing and the number of channels is not particularly limited.

  FIG. 1 shows the configuration of the main part of the optical wiring system in more detail. FIG. 1 (a) is a plan view seen from the back side of the first semiconductor chip 31, and FIG. FIG. 1C is a cross-sectional view taken along line AA shown in FIG. 1A, and FIG. 1C shows the arrangement relationship between the light emitting element array 6A and the light receiving element array 8A, and the light emitting elements 5 on these array substrates. 4 is a plan view showing the positional relationship between the light receiving element 7 and the light receiving element 7. FIG. In FIG. 1 (b), it is shown upside down from FIG. 1 (a) in accordance with the orientation of FIG. 3 described above. Further, FIG. 1A shows an optical waveguide array corresponding to input / output of 6 channels. Like FIG. 4, this number is for the convenience of drawing, and the number of channels is particularly limited. is not.

  Further, the optical waveguide shown in FIG. 1A is composed of a joined body of a core (the light guide path) and a clad, and a part or all of the clad is omitted and is replaced with an air layer or a substrate. It doesn't matter. Therefore, in FIG. 1A, only the light guide (core) is shown as the optical waveguide, and the cladding is not shown. Therefore, for example, 2a in the figure should be strictly called "first optical waveguide (core)", but is usually called "first optical waveguide" from the viewpoint of its function. Only when it is desired to show the light guide (core) itself, it will be referred to as “the light guide (core) of the first optical waveguide”. The use of this term is the same for FIG. 1B, and the same applies to Embodiments 2 to 4 described later.

  In the optical waveguide array 10A, as shown in FIG. 1A, a plurality of optical waveguides 2 are juxtaposed in the width direction, and as shown in FIG. 1B, each optical waveguide 2 has light incident end faces at both ends. 3 and the light emitting end face 4 are formed as 45-degree inclined reflection surfaces, and a light emitting element 5 and a light receiving element 7 are respectively arranged to face these inclined reflection surfaces.

  The operation will be described as follows. The electrical signal output from the first semiconductor chip 31 is converted into an optical signal by an attached circuit (not shown) and the light emitting element 5. The optical signal from the light emitting element 5 is incident on the 45-degree inclined reflection surface of the light incident end face 3, is totally reflected here, proceeds in the optical waveguide 2 a to the light emission end face side, and the 45-degree inclined reflection of the light emission end face 4. The light is totally reflected again by the surface and is received by the light receiving element 7 provided facing the surface. The optical signal is converted into an electric signal by the light receiving element 7 and transmitted to the second semiconductor chip as an electric signal. In this way, one light emitting element 5, one optical waveguide 2, and one light receiving element 7 form one set to form one signal transmission path.

  As described above, the basic configuration and function of each signal transmission path are the same as those of the conventional example shown in FIG. The greatest feature of the optical waveguide array 10A that is different from the conventional optical waveguide array 10E shown in FIG. 22A is that the both ends of each optical waveguide 2 are not aligned. Second, the optical waveguides 2a and 2b in which the directions in which light is guided are opposite to each other are alternately arranged, and third, the first and first The width of the optical waveguide (light guide path) 2 of the light incident portion 9 is enlarged by utilizing the space near the light incident portion 9 generated by the feature 2. Hereinafter, the reason why this structure has become possible and the advantages produced by this structure will be described.

  In the optical waveguide array manufacturing method according to the present embodiment, as will be described later, the constituent material of the light guide is formed into a light guide array using the mold, and the prototype of this mold is synchronized with the photosensitive resin layer. It is produced by exposing to tron radiation and developing. At this time, since the inclined reflecting surface is produced by irradiating synchrotron radiation from an oblique direction using a mask, the angle of the 45 ° inclined reflecting surface is changed for each waveguide by changing the position of the end of the mask opening. Can be provided at a desired position. This is a fundamental difference from the conventional method.

  As a result, as shown in FIG. 1A, both ends of each optical waveguide 2, particularly the light incident end face 3, are formed to be shifted from each other, and a space region can be created in the vicinity of the light incident end face 3.

  Furthermore, two optical waveguides 2a and 2b having opposite directions in which light is guided can be alternately arranged. As described above, in the conventional optical waveguide array 10E in which the 45-degree inclined reflection surfaces of the respective optical waveguides are formed in a straight line as described above, the light-emitting element 5 and the light-receiving element 7 face the 45-degree inclined reflection surface. And cannot be alternately arranged on a straight line, so that the structure is impossible. According to the present embodiment, since the 45-degree inclined reflection surface is formed by shifting, it is not necessary to arrange the light emitting element 5 and the light receiving element 7 on a straight line, and this structure becomes possible.

  More specifically, the optical waveguide 2 is divided into two groups. For example, the odd-numbered groups counted from the top of the figure are shifted to the left in the figure so that the optical signal is transmitted from the first semiconductor chip 31 to the second group. The first optical waveguide 2a is transmitted to the semiconductor chip 32, and even-numbered groups are shifted to the right in the figure, so that the optical signal is directed from the second semiconductor chip 32 toward the first semiconductor chip 31. It is assumed that the second optical waveguide 2b is transmitted. In this way, for example, on the first semiconductor chip 31 side, the light incident end face 3 is shifted to the left and the light emitting end face 4 is shifted to the right. Therefore, as shown in FIG. If the substrate on which 6A is formed is arranged on the left side and the substrate on which the light receiving element array 8A is formed is arranged on the right side, the light emitting element 5 is opposed to the light incident end face 3, and the light receiving element 7 is opposed to the light emitting end face 4. Can be made. Similarly, on the second semiconductor chip 32 side, if the substrate on which the light receiving element array 8A is formed is disposed on the left side and the substrate on which the light emitting element array 6A is formed is disposed on the right side,

  As shown in FIG. 1A, when the light incident end faces 3 and the light exit end faces 4 are alternately arranged, the light exit end faces 4 do not need to be enlarged. It can be used to widen the width of the light guide (core) 2 at the incident end face 3.

  FIG. 2 shows the shape of the light guide (core) 2 schematically shown in FIG. 1 closer to the actual shape, and FIG. 2 (a) shows four light guides (cores). ) Are juxtaposed, FIG. 2B is a cross-sectional view taken along line XX shown in FIG. 2A, and FIG. 2C is FIG. It is sectional drawing in the YY line shown to). However, FIG.2 (c) is expanding and showing 4 times compared with FIG.2 (a) and FIG.2 (b).

  The light guide (core) 2 has, for example, a very elongated shape having a length of 40 mm, a width of 5 μm, and a height of 15 μm. The shape of the cross section is a trapezoid whose side wall is inclined by about 5 ° from the vertical direction, which is suitable for improving the releasability when releasing from the mold after forming by injection molding or stamper molding. .

  The constituent material of the light guide (core) 2 is not particularly limited, but may be a polymer material such as PMMA (polymethyl methacrylate). By using a polymer-based material as the material of the light guide (core) 2, it becomes possible to manufacture by injection molding or stamping molding, and the manufacturing process of the optical waveguide array 10A is made as compared with the case of using a conventional quartz optical waveguide. Simplification and cost reduction can be achieved.

  The pitch between the light guide paths (cores) 2 is 10 μm, and the interval between the adjacent light guide paths (cores) 2 is 5 μm. The distance between the two closest light incident end faces 3 needs to be 100 μm or more in order to suppress optical interference and crosstalk between the light emitting elements 5. As is clear from FIG. 2A, the distance between the light incident end face 3 of one optical waveguide and the light incident end face 3 of one adjacent optical waveguide is the length direction of the light guide (core) 2. By increasing the deviation between the light incident end faces 3 in FIG. 1, the gap can be increased without being limited by the arrangement pitch of the light guide paths (cores) 2.

  Both end faces of the light guide path (core) 2 are inclined reflection surfaces of 45 degrees, and the projection size of the light emitting end face 4 (projection size on the electrode forming surface of the semiconductor chip to which the light emitting element 5 or the light receiving element 7 is fixed). The same applies hereinafter.) Is 15 μm × 5 μm. On the other hand, in the light incident part 9, the width of the light guide path (core) 2 increases linearly three times toward the light incident end face 3 using a nearby space. The projected size of the end face 3 is enlarged to 15 μm × 15 μm.

  The inclination of the side wall of the region where the cross section of the light guide path (core) is enlarged in the light incident portion 9 is not reflected by the side wall (boundary surface with the clad) but is transmitted to the clad, resulting in loss of light amount or stray light. It is necessary to make it sufficiently small so that leakage light that causes interference can be suppressed. Even in this case, the length of the region where the cross section of the light guide (core) is enlarged is at most several hundred μm, which is only a part of the entire length of the light guide (core).

  As shown in FIG. 2C, the projected pattern of the light incident end face 3 includes the light emitting element 5 having a diameter of about 10 μm with a margin. Therefore, if the light from the light emitting element 5 is a parallel light flux, the light incident end face 3 not only completely covers the light incident area, but also has some spread of light and optical axis deviation. Is less susceptible to that effect. On the other hand, when the light guide path is not enlarged, the projection size of the light incident end face 3 is 15 μm × 5 μm, and not only can the light from the light emitting element 5 having a diameter of about 10 μm be completely captured, It is easily affected by the displacement of the light source.

  FIG. 5 shows a tolerance for the deviation of the optical axis due to the displacement of the mounting position or the deformation of the board when the light emitting element 5 and the light incident end face 3 of the optical waveguide 2 are coupled by a collimating optical system using a convex lens having a diameter of 100 μm. Is further increased to ± 10 μm. The constituent material of the substrate 1 and the convex lens is not particularly limited as long as it transmits light to be used, but a glass substrate or a plastic substrate is usually preferable.

  In this way, according to the present embodiment, the efficiency and certainty that light from the light emitting element 5 is taken into the light guide path 2 can be improved. The amount of light loss due to the deviation of the optical axis is reduced, and the tolerance of positioning error between the light emitting element 5 and the light incident end face 3 is increased. Therefore, alignment between the light emitting element 5 and the optical waveguide array 10A is facilitated, and a large number of Collective passive alignment between the optical element and the optical waveguide array becomes possible, and mass productivity and yield are improved.

  The optical waveguide array 10A according to the present embodiment also has the following features.

  As mentioned in FIG. 2, the light incident end face 3 of one optical waveguide and the light incident end face 3 of one adjacent optical waveguide are formed at positions shifted in the length direction of the optical waveguide. Therefore, by increasing this deviation amount, the distance between the light incident end faces 3 can be increased without being limited by the pitch between the optical waveguides. If this operation is performed for n optical waveguides (three in FIG. 1A) and the first waveguide is sufficiently wide in the width direction, the position of the light incident end face 3 in the length direction is set to the first optical waveguide. Return to the same position. After that, only the same operation is repeated with n as a repeating unit.

  As a result, as can be seen from a comparison between FIG. 1C and FIG. 22C, the distance d between the light emitting elements 5 installed facing these light incident end faces 3 can be made sufficiently large. In addition, light interference and crosstalk between the light emitting elements can be suppressed. In addition, the optical waveguide array 10A can be integrated at a high density by reducing the pitch of the optical waveguide array without degrading the performance of the light emitting element.

  In addition, the distance between the electric wirings for connecting the input / output pads of the semiconductor chip to the light emitting element 5 and the light receiving element 7 can be shortened, and the countermeasure against high frequency becomes easy. This is because, as shown in FIG. 1A, in the optical waveguide array 10A, the optical waveguides 2a and 2b in which the light is guided in opposite directions are alternately arranged. As shown in FIG. 1C, the light emitting element 5 and the light receiving element 7 corresponding to the input and output connected to a specific circuit can be arranged close to each other. As a result, both the electric wiring 39A connecting the input pad 37 and the light receiving element 7 and the electric wiring 40A connecting the output pad 38 and the light emitting element 5 can be shortened, and high-frequency countermeasures are facilitated.

  Next, a method for manufacturing the optical waveguide array 10A will be described with reference to FIGS. 6 to 9 are cross-sectional views corresponding to the position of the line AA in FIG.

  First, the master mold 13 for manufacturing the optical waveguide array 10A is manufactured by the steps shown in FIGS. 6A to 8H.

  First, as shown in FIG. 6A, the photosensitive resin layer 11 is formed on the substrate 21. As the photosensitive resin constituting the photosensitive resin layer 11, for example, PMMA (polymethyl methacrylate) can be used. The film thickness of the photosensitive resin layer 11 corresponds to the height of the optical waveguide 2 to be formed, for example, about 15 μm.

  Next, as shown in FIG. 6B, a mask 22 that opens in the pattern of each optical waveguide 2 is installed in the vicinity of the photosensitive resin layer 11. The length of the mask opening is the length of the optical waveguide 2 excluding the end portion where the inclined reflecting surface is formed.

  Next, as shown in FIG. 6C, the photosensitive resin layer 11 is exposed by irradiating synchrotron radiation 23 perpendicularly to the surface of the photosensitive resin layer 11 using a mask 22. As a result, an exposed region 11 a of the photosensitive resin layer 11 is formed below the opening, and an unexposed region 11 d is left below the mask 22. The exposure region 11a corresponds to the optical waveguide 2 excluding the end portion where the inclined reflection surface is formed.

  Next, as shown in FIG. 7D, exposure is performed to form an inclined reflecting surface at one end. That is, the direction of irradiating the synchrotron radiation 23 is inclined by about 45 ° from the direction perpendicular to the surface of the photosensitive resin layer 11 to the length of the optical waveguide, and the mask 22 is used to irradiate the synchrotron radiation 23. Then, the photosensitive resin layer 11 is exposed. As an actual operation, instead of changing the direction of the synchrotron radiation 23, it is preferable to irradiate the substrate 21 with the direction of the substrate 21 inclined by about 45 ° in the opposite direction.

  As a result, the synchrotron radiation 23 is irradiated to the photosensitive resin layer 11 corresponding to the end portion that forms the inclined reflection surface of the optical waveguide below the mask 22, and a new exposure region 11b is formed. The boundary surface between the exposed region 11 b and the remaining unexposed region 11 e is formed at an angle of 45 ° with respect to the surface of the photosensitive resin layer 11, and this corresponds to an inclined reflecting surface.

  Next, as shown in FIG. 7E, exposure is performed to form the inclined reflection surface at the other end. That is, the direction of irradiating the synchrotron radiation 23 is inclined by about 45 ° from the direction perpendicular to the surface of the photosensitive resin layer 11 in the direction opposite to that shown in FIG. The synchrotron radiation 23 is irradiated to expose the photosensitive resin layer 11. As an actual operation, instead of changing the direction of the synchrotron radiation 23, it is preferable to irradiate the substrate 21 with the substrate 21 tilted in the opposite direction by 45 °.

  As a result, the synchrotron radiation 23 is irradiated to the photosensitive resin layer 11 corresponding to the end portion that forms the other inclined reflection surface of the optical waveguide below the mask 22, and a new exposure region 11c is formed. . The boundary surface between the exposed region 11c and the remaining unexposed region 11f is formed at an angle of 45 ° with respect to the surface of the photosensitive resin layer 11, and this corresponds to the other inclined reflecting surface.

  Next, as shown in FIG. 7F, development processing with a predetermined developer is performed, and the exposed regions (exposed region 11a, exposed region 11b, and exposed region 11c) of the photosensitive resin layer 11 are removed. As a result, only the unexposed regions 11e and 11f are left, and the opening 24 is formed in the portion where the exposed region of the photosensitive resin layer 11 is removed.

  Next, as shown in FIG. 8G, after depositing a metal such as nickel in the opening 24 by, for example, nickel electroforming plating, the surface is flattened to form the metal layer 12.

  Next, as shown in FIG. 8H, the unexposed areas 11e and 11f of the photosensitive resin layer 11 are dissolved and removed. As a result, a master mold 13 for manufacturing an optical waveguide array in which a plurality of metal layers 12 having the same shape as the optical waveguide 2 are formed on the substrate 21 is obtained. In the master mold 13, the surface to be a 45-degree inclined reflecting surface of each optical waveguide 2 is an exposed region 11 b and an unexposed region that are formed when the synchrotron radiation 23 is tilted by about 45 ° and exposed from an oblique direction. The boundary surface with 11e and the boundary surface between the exposed region 11c and the unexposed region 11f are surfaces formed by being transferred.

  Next, the optical waveguide array 10A is manufactured from the master mold 13 by the steps shown in FIGS. 8 (i) to 9 (m).

  First, as shown in FIG. 8I, the mother die 14 is formed on the substrate 21 and the master die 13 by, for example, nickel electroforming plating. On the surface of the mother mold 14, the convex portions of the master mold 13 are transferred to form concave portions.

  Next, as shown in FIG. 8J, the master mold 13 and the substrate 21 are released from the mother mold 14. At this time, by forming an oxide film or the like in advance at the interface between the mother mold 14 and the master mold 13, peeling at the interface between the two can be facilitated.

  Next, as shown in FIG. 9 (k), a clad (or a composite of a substrate and a clad formed thereon) 15 is brought into close contact with the mother mold.

  Next, as shown in FIG. 9 (l), the mother mold 14 and the cladding 15 are fixed in an injection molding cavity, and an organic material such as molten PMMA is injected into the cavity. Then, the optical waveguide array 10A composed of a plurality of light guide paths (cores) 2 to which the concave portions of the mother mold 14 are transferred is formed.

  Next, as shown in FIG. 9 (m), the optical waveguide array 10 </ b> A is released from the mother die 14. The optical waveguide array 10A is configured as shown in FIGS. 1A and 1B. A plurality of optical waveguides 2 are formed, and light incident end surfaces 3 each having a 45-degree inclined reflecting surface at both ends of each optical waveguide 2 are formed. And the light emission end surface 4 is provided.

  In each optical waveguide 2, the light incident end surface 3 and the light emitting end surface 4 made of a 45 ° inclined reflection surface are exposed on the photosensitive resin layer 11 when the synchrotron radiation 23 is irradiated obliquely at 45 °. This is a surface formed by transferring the interface between the region 11b and the unexposed region 11e and between the exposed region 11c and the unexposed region 11f. In the present embodiment, the exposure method for forming the inclined reflection surface on the undercut side in FIG. 7 has been described, but conversely, the exposure method for forming the inclined reflection surface on the non-undercut side may be used.

  Synchrotron radiation 23 used in the method of manufacturing an optical waveguide array according to the present embodiment is emitted from infrared to ultraviolet and X-rays emitted when an electron trajectory moving at a speed close to the speed of light is bent by a magnetic field. It is an electromagnetic wave with a wide wavelength distribution. The synchrotron radiation light source can be used from a large device having a diameter of several kilometers to a small device having several meters.

  The synchrotron radiation light 23 is light having a low intensity but high energy compared to, for example, laser light, and can completely expose the photosensitive resin layer 11 having a thickness of about 10 μm to a position reaching the substrate 21. The opening 24 having an inclined surface corresponding to the 45 ° inclined reflecting surface can be formed in the photosensitive resin layer 11 with high accuracy.

  When exposed using a semiconductor laser or other ordinary light source instead of the synchrotron radiation 23, the photosensitive resin layer 11 cannot be completely exposed to the position reaching the substrate 21 due to the thickness of about 10 μm. .

  As described above, according to the method of manufacturing an optical waveguide array according to the present embodiment, it is difficult to use a conventional method of forming a 45-degree inclined reflective surface by mechanical processing using a disk blade saw or the like. It is possible to easily and efficiently form a fine and complex optical waveguide array 10A in which the light incident portion or the light emitting portion is shifted in the length direction of the waveguide by batch processing. As a result, it is possible to contribute to the high-density integration of the optical waveguide 10A described above.

  In addition, in the method for manufacturing an optical waveguide array according to the present embodiment, a mechanical processing step using an expensive disk blade saw or the like is unnecessary, and the manufacturing cost can be reduced.

Embodiment 2
Also in the present embodiment, the first semiconductor chip 31 and the second semiconductor chip 32 are coupled by optical wiring using an optical waveguide array by the optical waveguide surface mounting method shown in FIG.

  FIG. 10 shows in detail the configuration of the main part of the optical wiring system using the optical waveguide array 10B based on the second embodiment. FIG. 10 (a) is viewed from the back side of the first semiconductor chip 31. FIG. 10B is a cross-sectional view taken along the line BB shown in FIG. 10A, and FIG. 10C is an arrangement relationship between the light emitting element array 6B and the light receiving element array 8B. FIG. 4 is a plan view showing the positional relationship between the light emitting element 5 and the light receiving element 7 on the array substrate. In FIG. 10 (b), corresponding to FIG. 3, FIG. 10 (a) is shown upside down.

  In the optical waveguide array 10B, as shown in FIG. 10 (a), a plurality of optical waveguides 2 are juxtaposed in the width direction, and as shown in FIG. 10 (b), each optical waveguide 2 has light incident end faces at both ends. 3 and the light emitting end face 4 are formed as 45-degree inclined reflection surfaces, and a light emitting element 5 and a light receiving element 7 are respectively arranged to face these inclined reflection surfaces.

  As shown in FIG. 10 (b), one light emitting element 5, one optical waveguide 2, and one light receiving element 7 form a set to form one signal transmission path. The basic configuration and function of the transmission line are the same as those in the first embodiment. In addition, since the constituent material and manufacturing method of the optical waveguide 2 are the same, only the differences will be noted and described below.

  When the optical waveguide array 10B is compared with the optical waveguide array 10A shown in FIG. 1A, the optical waveguides 2a and 2b whose light guiding directions are opposite to each other are arranged alternately. The incident end face 3 and the light exit end face 4 are arranged at positions shifted in the length direction of the optical waveguide, and the space region in the vicinity of the light incident part 9 generated thereby makes it possible to Although it is common that the width of the optical waveguide (light guide path) is enlarged, the difference is that the positions of the light incident portions are aligned in the length direction of the optical waveguide.

  Therefore, although the optical waveguide array 10B has the same effect as the optical waveguide array 10A described in the first embodiment, it is inferior in the following two points.

  Like the optical waveguide arrays 10A and 10B, the optical waveguide 2b is disposed on both sides of the optical waveguide 2a, and the light emitting end face 4 of the optical waveguide 2b is longer in the length direction than the light incident end face 3 of the optical waveguide 2a. When formed so as to be shifted to the center side (right direction in the figure), a space region is formed on the extension line of the light emitting end face 4 (left direction in the figure). Therefore, using this space region, the optical waveguide 2a The width of the light guide path (core) in the light incident end face 3 can be widened.

  As an example, as shown in FIG. 2, a case is considered in which optical waveguides (light guides) having a width of 5 μm are arranged with an interval of 5 μm (pitch is 10 μm) between adjacent optical waveguides (light guides). The optical waveguide (light guide path) that widens in the region can also be widened until the distance from the adjacent optical waveguide (light guide path) becomes 5 μm. In this case, in the structure of the optical waveguide array 10A, when the adjacent optical waveguide (light guide path) 2a is approached to the limit, it can be widened to a maximum of 25 μm (5 times). On the other hand, in the structure of the optical waveguide array 10B, the widened optical waveguides (light guides) collide with each other as shown in FIG. 10A, so that the width of the light guides that can be widened is 15 μm (three times). It is limited to.

  Therefore, also in this embodiment, the efficiency and certainty that the light from the light emitting element 5 is taken into the light guide path 2 can be improved, and the light loss due to the deviation of the optical axis is reduced. Since the tolerance of the positioning error between the light incident end face 3 and the light incident end face 3 is increased, the alignment between the light emitting element 5 and the optical waveguide array 10B is facilitated, but the effect is small as compared with the first embodiment.

  Further, the distance between the light incident end faces 3 is set to be twice the pitch between the optical waveguides by alternately arranging the optical waveguides 2a and 2b in which the light is guided in the opposite direction. However, it is the same as the prior art in that it is determined by the pitch between the optical waveguides. For example, in the case of the above numerical example, the distance between the light incident end faces 3 is 20 μm, which is necessary for suppressing light interference and thermal crosstalk between the light emitting elements 5 installed facing them. It is not enough for 100μm. Therefore, when the optical interference and thermal crosstalk between the light emitting elements 5 cannot be sufficiently suppressed, and when it is necessary to sufficiently suppress the optical interference and thermal crosstalk between the light emitting elements 5, between the optical waveguides. The only way to deal with this is to increase the pitch, and the optical waveguide mounting density is limited by light interference and thermal crosstalk between the light emitting elements 5.

  Even if there is such a problem, the advantage of the optical waveguide array 10B is that the effect can be obtained with the simple structure shown in FIG.

  Further, in the optical waveguide array 10B, as in the optical waveguide array 10A, the optical waveguides 2a and 2b whose directions of light are opposite to each other are alternately arranged, so that one set of these is input and output. And the corresponding light emitting element 5 and light receiving element 7 can be arranged close to each other. As a result, either the electric wiring 39B connecting the input pad 37 and the light receiving element 7 or the electric wiring 40B connecting the output pad 38 and the light emitting element 5 can be shortened, and high frequency countermeasures are facilitated.

  Further, since the optical waveguide array 10B is manufactured by injection molding using the mold as in the optical waveguide array 10A, a mechanical processing step using an expensive disk blade saw or the like is unnecessary, and the manufacturing cost is reduced. Can be reduced. Further, the mold can be easily and efficiently formed by batch processing with synchrotron radiation.

Embodiment 3
Also in the present embodiment, the first semiconductor chip 31 and the second semiconductor chip 32 are coupled by optical wiring using an optical waveguide array by the optical waveguide surface mounting method shown in FIG.

  FIG. 11 shows in detail the configuration of the main part of the optical wiring system using the optical waveguide array 10C based on the third embodiment. FIG. 11A is viewed from the back side of the first semiconductor chip 31. 11B is a cross-sectional view taken along the line CC shown in FIG. 11A, and FIG. 11C is an arrangement relationship between the light emitting element array 6C and the light receiving element array 8C. FIG. 4 is a plan view showing the positional relationship between the light emitting element 5 and the light receiving element 7 on the array substrate. In FIG. 11B, corresponding to FIG. 3, FIG. 11A is shown upside down.

  In the optical waveguide array 10C, as shown in FIG. 11 (a), a plurality of optical waveguides 2 are juxtaposed in the width direction, and as shown in FIG. 11 (b), each optical waveguide 2 has light incident end faces at both ends. 3 and the light emitting end face 4 are formed as 45-degree inclined reflection surfaces, and a light emitting element 5 and a light receiving element 7 are respectively arranged to face these inclined reflection surfaces.

  As shown in FIG. 11 (b), one light emitting element 5, one optical waveguide 2, and one light receiving element 7 form a set to form one signal transmission path. The basic configuration and function of the transmission line are the same as those in the first embodiment. In addition, since the constituent material and manufacturing method of the optical waveguide 2 are the same, only the differences will be noted and described below.

  In the optical waveguide array 10 </ b> A shown in FIG. 1A, optical waveguides 2 a and 2 b in which directions in which light is guided are opposite to each other are alternately arranged. On the other hand, in the optical waveguide array 10C shown in FIG. 11A, two optical waveguides 2a (generally n) are combined into one set, and two optical waveguides 2b3 (generally n). ) In a set can be regarded as being alternately arranged.

  As shown in FIG. 11A, when the optical waveguide 2a is juxtaposed, one side surface of the optical waveguide 2a (the upper side surface in FIG. 11A) is blocked by the other optical waveguide 2a and cannot be used. Therefore, only the side wall on the other side (the lower side surface in FIG. 11A) of the light guide path (core) in the light incident portion 9 of the optical waveguide 2a is inclined and widened. In this case, it is important that the light incident portions 9 of the three optical waveguides 2a shown in the figure are all formed in the space region formed on the extension line (left side of the drawing) of the light emitting end face 4 of the three optical waveguides 2b. By using this space area, the width of the light guide path (core) at the light incident end face 3 can be widened, and by increasing the number of n (in principle), the width of the light guide path can be increased as much as possible. It is possible to form a space area.

As described above, according to the present embodiment, the width of the light guide path (core) in the light incident end face 3 can be increased, and the efficiency and certainty that the light from the light emitting element 5 is taken into the light guide path 2 can be improved. . The amount of light loss due to the deviation of the optical axis is reduced, and the tolerance of positioning error between the light emitting element 5 and the light incident end face 3 is increased. Therefore, alignment between the light emitting element 5 and the optical waveguide array 10A is facilitated, and a large number of Collective passive alignment between the optical element and the optical waveguide array becomes possible, and mass productivity and yield are improved. At this time, the light emitting element 5 and the light incident end face 3 of the optical waveguide 2 are preferably coupled with each other by a collimating optical system using the convex lens shown in FIG.
This embodiment

  The optical waveguide array 10C according to the present embodiment also has the following characteristics.

  As described in FIG. 2, the light incident end face 3 of one optical waveguide and the light incident end face 3 of the adjacent optical waveguide are formed at positions shifted in the length direction of the optical waveguide. By increasing the amount, the distance between the light incident end faces 3 can be increased without being limited by the pitch between the optical waveguides. As a result, as can be seen by comparing FIG. 11 (c) and FIG. 22 (c), the distance d between the light emitting elements 5 installed facing these light incident end faces 3 can be made sufficiently large. In addition, light interference and crosstalk between the light emitting elements can be suppressed. In addition, the optical waveguide array 10A can be integrated at a high density by reducing the pitch of the optical waveguide array without degrading the performance of the light emitting element.

  In addition, the distance between the electric wirings for connecting the input / output pads of the semiconductor chip to the light emitting element 5 and the light receiving element 7 can be shortened, and the countermeasure against high frequency becomes easy. This is because, as shown in FIG. 11A, in the optical waveguide array 10C, the optical waveguides 2a and 2b whose light directions are opposite to each other are separated by only three optical waveguides. One set can be assigned to an input and an output to be connected to a specific circuit, and the corresponding light emitting element 5 and light receiving element 7 can be arranged close to each other as shown in FIG. As a result, both the electric wiring 39A connecting the input pad 37 and the light receiving element 7 and the electric wiring 40A connecting the output pad 38 and the light emitting element 5 can be shortened, and high-frequency countermeasures are facilitated.

  Further, since the optical waveguide array 10C is manufactured by injection molding using the mold as in the optical waveguide array 10A, a mechanical processing step using an expensive disk blade saw or the like is unnecessary, and the manufacturing cost is reduced. Can be reduced. Further, the mold can be easily and efficiently formed by batch processing with synchrotron radiation.

Embodiment 4
An optical waveguide array according to the present invention efficiently captures light from a signal source and emits it to a screen such as a head mounted display, for example, R (red), G (green) and B (blue). The present invention can also be applied to a full-color display that displays three primary color lights.

  FIG. 12 shows the configuration of the main part of such an optical information processing apparatus. FIG. 1A is a plan view seen from the back side of the semiconductor chip 41, and FIG. It is sectional drawing in the DD line shown to 41 (a). In FIG. 41 (b), it is shown upside down from FIG. 41 (a). FIG. 41 (a) shows an optical waveguide array corresponding to the output of RGB 4 channels, but this number is for the convenience of drawing and the number of channels is not particularly limited.

  In the optical waveguide array 10D shown in FIG. 12A, optical waveguides 2R and 2G that guide red light, green light, and blue light corresponding to R (red), G (green), and B (blue). And 2B are arranged so as to form one set, the light emitting elements 5R, 5G, and 5B are arranged to face the light incident end faces 3R, 3G, and 3B, respectively, and the light emitting end faces 4R, 4G are arranged. The signal light of each RGB color is emitted from 4B to the screen 42 to form unit pixels.

  At this time, since the directions of light guided by the optical waveguides 2R, 2G, and 2B are the same, an optical waveguide that cannot increase the width of the light guide path at the light incident end faces 3R, 3G, and 3B is generated. In such a case, among the light emitting elements 5R, 5G, and 5B, the light emitting element having the strongest emission intensity may be assigned to the optical waveguide in which the width of the light guide path cannot be increased.

  It should be pointed out that there is an optimum range for the inclination of the side wall in the region where the cross section of the light guide path (core) is enlarged in the light incident portion 9 described in the first to fourth embodiments.

FIG. 13 shows a result obtained by simulating the relationship between the length L of the light guide and the loss of light when light is guided in an optical waveguide having an inclined side wall in an optical waveguide made of oxetane resin. It is a graph which shows. In Figure 13, W _in denotes the width of the light incident end face was changed by 100μm from 200μm to 600 .mu.m. W _out is the width of the light emitting end face, and is constant at 50 μm.

As can be seen from the graph of FIG. 13, when any W be a value of _in too small a length L of the core, it can be seen that the rapid loss increases. In addition, the length L at which this sudden increase in loss occurs is approximately proportional to W _in (exactly W _in −W _out ). This is because the inclination of the side surface of the light guide becomes tight, and if the angle (α shown in FIG. 13) formed by the side surface of the light guide and the width direction center line of the light guide becomes too large, the light enters the wall at a deep angle. This is thought to be because light that leaks into the cladding without being totally reflected increases. According to the simulation, in the optical waveguide made of oxetane resin, α is preferably 3.5 ° or less in order to suppress the light loss within 2 dB.

  On the other hand, if the inclination is too small, the light incident part and the light emitting element array become unnecessarily large, causing a problem. Therefore, it is necessary to select an appropriate inclination according to the material of the optical waveguide and the allowable loss of light.

Embodiment 5
In place of the surface mounting method of fixing the optical waveguide array to the mounting substrate shown in FIG. 3, the optical waveguide array 10A to 10C has positioning means and an installation portion for positioning and installing the optical waveguide array 10A. A socket in which at least one of a light emitting element 5 for performing incidence and a light receiving element 7 for receiving light emitted from the optical waveguide 2 is disposed corresponding to the optical waveguide 2 is used, and the optical waveguide is between a pair of sockets. An example of forming an optical interconnection system by forming a photoelectric composite device that spans an array will be described below.

  FIG. 14 is a schematic perspective view of the socket. 14A is a schematic perspective view of the socket as viewed from the surface side on which the optical waveguide 2 is installed, and FIG. 14B is a schematic perspective view of the socket as viewed from the opposite surface side of FIG. It is.

  Assuming that the optical waveguide array 10A is used as the optical waveguide array, as shown in FIG. 14, the socket 51 is provided with positioning means having a concavo-convex structure for positioning and fixing the optical waveguide array 10A. . Specifically, the concavo-convex structure has a recess 52 for fitting the optical waveguide array 10A and positioning the width direction thereof, and a protrusion 53 for positioning the length direction of the optical waveguide array 10A. Yes. Further, the depth of the recess 52 is larger than the thickness of the optical waveguide array 10A.

  Further, on the convex surface 54 of the concavo-convex structure of the socket 51, a conduction means, for example, a terminal pin 55, for conducting the front and back surfaces of the socket 51 is provided. Then, an interposer on which the light emitting element 5 and / or the light receiving element 7 is mounted is fixed on the convex surface 54 of the concavo-convex structure, as will be described later.

  As the material of the socket 51, a conventionally known material can be used as long as it is an insulating resin. Examples thereof include glass-filled PES (polyethylene sulfide) resin and glass-filled PET (polyethylene terephthalate) resin. Such a socket 51 material already has a lot of data on its type, insulation, reliability, etc., and there are many manufacturers. Therefore, it is a structure that is easy to accept in all of its functions, costs, reliability, etc., and can be easily integrated with the existing printed wiring board mounting process.

  Although the manufacturing method of the socket 51 is not specifically limited, For example, it can manufacture easily by shaping | molding using the metal mold | die which has the said uneven structure.

  FIG. 15 is a schematic perspective view (a) of the photoelectric composite device 56 using the socket 51 and an exploded view (b) of FIG.

  As shown in FIG. 15, the photoelectric composite device 56 includes a pair of sockets 51 and an optical waveguide array 10 </ b> A installed in the socket 51, and the optical waveguide array 10 </ b> A is bridged between the pair of sockets 51. ing. Although not shown here, the optical waveguide array 10A includes a plurality of optical waveguides 2 arranged in parallel as shown in FIG. At this time, since the optical waveguide array 10A is not in contact with a printed wiring board to be described later, it is possible to effectively prevent the optical waveguide array 10A from being destroyed by heat dissipation of the semiconductor integrated circuit chip. .

  Further, an interposer 70 in which semiconductor integrated circuit chips 71 a and 71 b, a light emitting element (not shown) (for example, a laser) and / or a light receiving element (not shown) are mounted on the convex surface 54 of the uneven structure of the socket 51. It is fixed.

  In the interposer 70, for example, as shown in FIG. 16, a semiconductor integrated circuit chip 71 is mounted on one surface side (FIG. 16A), and light is incident on the optical waveguide array 10A on the other surface side. A light-emitting element array 6A for performing light emission and / or a light-receiving element array 8A for receiving light emitted from the optical waveguide array 10A are mounted, and a rewiring electrode 72 is provided in the periphery (FIG. 16B). )). The light emitting element array 6A and the light receiving element array 8A each include a plurality of light emitting elements 5 and light receiving elements 7 disposed at positions corresponding to the light incident / exit portions of the respective optical waveguides 2 (not shown). In the gaps between the light emitting elements 5 and the light receiving elements 7, penetrating electrodes for electrical connection between the light emitting elements and the light receiving elements and the semiconductor integrated circuit chip are arranged (not shown).

  When the pair of sockets 51 in which the optical waveguide array 10A is installed in the recess 52 and the interposer 70 are fixed, the side of the interposer 70 on which the light emitting element array 6A and / or the light receiving element array 8A are mounted. Is fixed so that the terminal pin 55 of the socket 51 and the rewiring electrode 72 of the interposer 70 are electrically connected.

  Further, as described above, by forming the depth of the recess 52 of the socket 51 to be larger than the thickness of the optical waveguide array 10A, as shown in FIG. 15A, one surface 73 of the optical waveguide array 10A. A space can be formed between the side and the surface side of the interposer 70 on which the light emitting element array 6A and / or the light receiving element array 8A are mounted.

  As described above, the semiconductor integrated circuit chip 71 is mounted on the socket 51 via the interposer 70, the one surface 73 side of the optical waveguide array 10A, the light emitting element array 6A and / or the light receiving element of the interposer 70. By forming a space 75 between the surface on which the array 8A is mounted, even if the semiconductor integrated circuit chip 71 generates heat when the photoelectric composite device 56 is used, the optical waveguide array 10A is destroyed by this heat. Can be effectively prevented.

  This operation mechanism is as follows. An electrical signal transmitted from one semiconductor chip 71a is converted into an optical signal by the light emitting element 5 (not shown) corresponding to this output of the light emitting element array 6A, and is emitted as an optical signal by laser light, for example. The emitted optical signal enters a light incident portion of a corresponding optical waveguide 2 (not shown) of the optical waveguide array 10A, propagates through the optical waveguide 2, and is emitted from the light emitting portion of the optical waveguide 2. . The optical signal emitted from the optical waveguide 2 is received by the light receiving element 7 (not shown) corresponding to this output of the light receiving element array 8A, converted into an electric signal, and transmitted to the other semiconductor chip 71b as an electric signal. Is done.

  The photoelectric composite device 56 can constitute an optical wiring system in which the optical waveguide 2 is used as an optical wiring. That is, the photoelectric composite device 56 is fixed while being electrically connected to the printed wiring board.

  According to the photoelectric composite device 56, the optical waveguide array 10A can be electrically connected to the printed wiring board in a state where the optical waveguide array 10A is installed in the recess 52 of the socket 51. Therefore, the existing mounting structure of the printed wiring board can be used as it is. Structure. Therefore, if a region where the socket 51 can be installed is provided on the printed wiring board, other general electric wiring can be formed by a conventional process.

  Moreover, even if the optical waveguide 2 is vulnerable to a high temperature process, for example, after fixing the socket 51 to the printed wiring board, and after completing all the mounting processes including the high temperature process such as solder reflow and underfill resin sealing, Since the optical waveguide array 10A can be installed in the recess 52 of the socket 51, the optical waveguide 2 can be mounted without suffering damage due to high temperature.

  Further, since the socket 51 can be made of a resin having higher rigidity than that of the printed wiring board, the light coupling between the light emitting element 5 and / or the light receiving element 7 and the optical waveguide 2 can be performed on the socket 51. The mounting accuracy required for optical coupling can be easily secured. For example, the assembly accuracy of the order of several μm can be secured by the current mold technology. Therefore, it is possible to increase the density of the optical bus.

  Further, since the semiconductor integrated circuit chip 71 and the light emitting element array 6A and / or the light receiving element array 8A can be installed close to the upper and lower surfaces via the interposer 70, the semiconductor integrated circuit chip 71, The wiring length between the light emitting element 5 and / or the light receiving element 7 can be shortened. Therefore, countermeasures against noise and crosstalk in the electric signal are facilitated, and the light modulation speed can be improved.

  Further, in the electrical wiring structure according to the conventional example, since the optical waveguide is directly provided on the printed wiring board, the number of pins and wirings drawn from the semiconductor integrated circuit chip 71 increases as the function of the semiconductor integrated circuit chip 71 increases. The optical waveguide 2 hinders the degree of freedom in designing the printed wiring board. As a result, it has become difficult to increase the functionality of the printed wiring board, and as a result, it has become a situation that relies on SOC (system on chip) to store all functions in one chip. On the other hand, according to the photoelectric composite device 56, the optical waveguide array 10A can be electrically connected to the printed wiring board in a state where it is installed in the recess 52 of the socket 51. The optical wiring system can be developed on a printed wiring board at a low cost and with a high degree of freedom while ensuring the degree of freedom of the design, high-speed distributed processing on the printed wiring board, high functionality in total electronic equipment, In addition, it can be expected to shorten the development around TAT (turn around time).

  Next, an example of a method for manufacturing the photoelectric composite device 56 will be described with reference to FIGS. 17 and 18 are cross-sectional views of the photoelectric composite device 56 shown in FIG. 15A at a position corresponding to the ZZ line.

  First, as shown in FIGS. 17A and 17B, a pair of sockets 51 are mounted on a printed wiring board 61. At this time, an electrode (not shown) on the printed wiring board 64 and the terminal pin 55 of the socket 51 are aligned so that the electrode and the socket 51 are electrically connected.

  Next, although not shown, other electronic components and the like are mounted on the printed wiring board 64 and electrical wiring is formed.

  Next, as shown in FIG. 17C, the optical waveguide array 10 </ b> A is installed in the recess 52 of the socket 51, and the optical waveguide array 10 </ b> A is bridged between the pair of sockets 51. At this time, positioning in the length direction of the optical waveguide array 10A can be easily performed by the protrusions 53 as the uneven structure provided in the socket 51, and positioning in the width direction of the optical waveguide array 10A is performed by the recess 52. It can be done easily. Since the optical waveguide array 10A is installed in the recess 52 of the socket 51, the optical waveguide array 10A and the printed wiring board 64 are not in contact with each other.

  The means for fixing the optical waveguide array 10A to the socket 51 is not particularly limited, and for example, an adhesive resin can be used. Specifically, first, as shown in FIG. 19A, a groove 66 is formed in an arbitrary shape on the bottom surface of the recess 52 of the socket 51. At this time, the groove is formed so that the end of the groove is located up to the periphery of the protrusion 53 of the socket 51. Next, as illustrated in FIG. 19B, the optical waveguide array 10 </ b> A in which a plurality of optical waveguides 67 are arranged side by side is installed in the recess 52 of the socket 51. As described above, the positioning in the length direction and the width direction of the optical waveguide array 10 </ b> A can be easily performed by the protrusion 53 and the recess 52 provided in the socket 51. Here, since the groove 66 is formed so as to be located up to the peripheral portion of the protrusion 53, a part of the groove 66 is not covered with the optical waveguide array 10A. Next, as shown in FIG. 19 (c), the adhesive resin is injected from a part of the groove 66 not covered with the optical waveguide array 10 </ b> A by using a dispenser 68 or the like and hardened, whereby the concave portion of the socket 51 is formed. The optical waveguide array 10 </ b> A can be bonded and fixed to 52.

  After the optical waveguide array 9 is installed in the socket 51 as described above, for example, MPU 71a or DRAM (Dynamic Random Access) as the semiconductor integrated circuit chip is formed on the convex surface 54 of the socket 51 as shown in FIG. Memory) 71b and the interposer 70 on which the light emitting element array 6A and / or the light receiving element array 8A are mounted are fixed. At this time, the surface side of the interposer 70 on which the light emitting element array 6A and / or the light receiving element array 8A is mounted is configured to be in contact with the convex surface 54 of the socket 51, and terminal pins (not shown) exposed on the convex surface 54 of the socket 51 are illustrated. And the rewiring electrode 72 of the interposer 70 are fixed so as to be electrically connected.

  Next, as shown in FIG. 18E, aluminum fins 65 are installed on the MPU 71a and the DRAM 71b, respectively.

  As described above, an optical wiring system in which the optical waveguide 67 is used as an optical wiring can be configured using the photoelectric composite device 56.

  Here, FIG. 20 is a schematic diagram illustrating an example in which the photoelectric composite device 56 is developed on the printed wiring board 64. For example, by standardizing the optical waveguide module, it can be freely deployed in four directions.

  According to the present embodiment, the optical waveguide array 10A can be electrically connected to the printed wiring board 64 in a state where the optical waveguide array 10A is installed in the recess 52 of the socket 51, so that the mounting structure of the existing printed wiring board 14 is maintained as it is. Can be used. Therefore, if a region where the socket 51 can be installed is provided on the printed wiring board 64, other general electric wiring can be formed by a conventional process.

  Even if the optical waveguide array 10A is vulnerable to a high temperature process, as described above, all the mounting processes including the high temperature process such as fixing the socket 51 to the printed wiring board 64 and further solder reflow and underfill resin sealing. After completing the above, the optical waveguide array 10A is installed in the recess 52 of the socket 51, so that the optical waveguide can be mounted without suffering damage due to high temperature.

  In addition, since the socket 51 can be made of a resin having higher rigidity than the printed wiring board 64, the light emitting element and / or the light receiving element and the optical waveguide can be optically coupled on the socket 51. The mounting accuracy required for optical coupling can be easily secured. For example, the assembly accuracy of the order of several μm can be secured by the current mold technology. Therefore, it is possible to increase the density of the optical bus.

  Further, since the semiconductor integrated circuit chips 71a and 71b and the light emitting element array 6A and / or the light receiving element array 8A can be installed close to the upper and lower surfaces via the interposer 70, the semiconductor integrated circuit chip 71a. , 71b and the wiring length between the light emitting element and / or the light receiving element can be shortened. Therefore, countermeasures against noise and crosstalk in the electric signal are facilitated, and the light modulation speed can be improved.

  In addition, since the optical waveguide array 10A can be electrically connected to the printed wiring board 64 in a state where it is installed in the concave portion 2 of the socket 51, the high density wiring of the printed wiring board 64 and the degree of design freedom are ensured. However, optical wiring systems can be deployed on printed wiring boards at a low cost and with a high degree of freedom. High-speed distributed processing on printed wiring boards, high functionality in total electronic equipment, and short development of TAT (turn around time) etc. can be expected.

  Further, the semiconductor integrated circuit chips 71a and 71b are mounted on the socket 51 via the interposer 70, the one surface 73 side of the optical waveguide array 10A, and the light emitting element array 6A and / or the light receiving element of the interposer 70. By forming a space 75 between the surface on which the array 8A is mounted, even if the semiconductor integrated circuit chip 71 generates heat when the photoelectric composite device 56 is used, the optical waveguide array 10A is destroyed by this heat. Can be effectively prevented.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  As long as the light incident portion of the optical waveguide is displaced from the light incident portion or the light emitting portion of the adjacent optical waveguide, various other forms can be adopted as the shape, configuration, and the like of the optical waveguide array. For example, a plurality of optical waveguides may be gathered radially, or planar aggregates juxtaposed in the width direction may be further stacked.

  Further, optical materials other than those exemplified can be used as the optical material constituting the optical waveguide array. Furthermore, the manufacturing method of the optical waveguide array mentioned above is an example for manufacturing the optical waveguide array of the said structure, It is not limited to this. In addition, various modifications can be made without departing from the scope of the present invention.

  The optical waveguide array of the present invention is the backbone of an optical information processing apparatus that can be applied to various places such as between electronic devices, between boards in an electronic device, particularly between semiconductor chips in the board, for example, an optical wiring system. It is suitably used as an optical waveguide array or the like that forms a signal transmission path, and can contribute to the construction of a high-speed, high-density, low-cost optical transmission / optical communication system. In addition to this, the present invention can be applied to a display or the like by selecting a light source or the like.

The top view (a) of the optical wiring system main part using the optical waveguide array based on Embodiment 1 of this invention, sectional drawing (b) in the AA line of the top view, the light emitting element 5, and the light receiving element 7 It is a top view (c) which shows the positional relationship of these. The top view (a) and sectional drawing (b, c) which show the structure of an optical waveguide are the same. It is a perspective view which shows the mounting state of the optical wiring system by an optical waveguide surface mounting system similarly. It is a top view which shows the main system structures of the optical wiring system by the same optical waveguide surface mounting system. FIG. 4 is an explanatory diagram showing a configuration of a collimating optical system provided between the light emitting element and the light incident end face 3 of the optical waveguide array. It is sectional drawing which shows the manufacturing process of an optical waveguide array similarly. It is sectional drawing which shows the manufacturing process of an optical waveguide array similarly. It is sectional drawing which shows the manufacturing process of an optical waveguide array similarly. It is sectional drawing which shows the manufacturing process of an optical waveguide array similarly. The top view (a) of the optical wiring system main part using the optical waveguide array based on Embodiment 2 of this invention, sectional drawing (b) in the BB line of the top view, the light emitting element 5, and the light receiving element 7 It is a top view (c) which shows the positional relationship of these. The top view (a) of the optical wiring system main part using the optical waveguide array based on Embodiment 3 of this invention, sectional drawing (b) in CC line of the top view, the light emitting element 5, and the light receiving element 7 It is a top view (c) which shows the positional relationship of these. The top view (a) of the optical wiring system main part using the optical waveguide array based on Embodiment 4 of this invention, sectional drawing (b) in the DD line of the top view, the light emitting element 5, and the light receiving element 7 It is a top view (c) which shows the positional relationship of these. It is a graph which shows the relationship between the length of a core, and the loss of light at the time of guiding light using the optical waveguide with an inclined side wall. It is a schematic perspective view of the socket based on Embodiment 5 of this invention. 2 is a schematic perspective view of the photoelectric composite device. FIG. It is a schematic perspective view of an interposer. It is a schematic sectional drawing which shows an example of the manufacturing method of a photoelectric composite apparatus in order of a process. It is a schematic sectional drawing which shows an example of the manufacturing method of a photoelectric composite apparatus in order of a process. It is a schematic plan view of a partial process of the manufacturing method of the photoelectric composite device. It is a schematic plan view of an example of the mounting structure of the photoelectric composite device. It is explanatory drawing which shows an example of the optical signal transmission coupling | bonding technique by optical wiring. Plan view (a) of a main part of an optical wiring system using a conventional optical waveguide array, a cross-sectional view (b) taken along the line EE of the plan view, and a plan view showing the positional relationship between the light emitting element 5 and the light receiving element 7 (C). It is sectional drawing (a) and a top view (b) explaining the formation method of the conventional inclined reflective surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Optical waveguide (light guide), 2R, 2G, 2B ... Optical waveguide,
2a ... 1st optical waveguide, 2b ... 2nd optical waveguide, 3 ... Light incident end surface,
3R, 3G, 3B ... light incident end face, 4 ... light exit end face, 4R, 4G, 4B ... light exit end face,
5 ... Light emitting element, 5R, 5G, 5B ... Light emitting element, 6A-6E ... Light emitting element array,
7: Light receiving element, 8A to 8E ... Light receiving element array, 9 ... Light incident part,
10A to 10E: Optical waveguide array, 11: Photosensitive resin,
11a, 11b, 11c ... exposed area, 11d, 11e, 11f ... unexposed area,
12 ... Metal layer, 13 ... Master mold, 14 ... Mother mold, 15 ... Clad, 21 ... Substrate,
22 ... Mask, 23 ... Synchrotron radiation, 31 ... First semiconductor chip,
32 ... second semiconductor chip, 33 ... mounting substrate (printed wiring board), 34 ... metal post, 35 ... solder bump, 36 ... mold resin, 37 ... input pad, 38 ... output pad,
39A to 39E, 40A to 40E ... electric wiring, 41 ... semiconductor chip, 42 ... screen, 51 ... socket, 52 ... concave, 53 ... projection, 54 ... convex surface, 55 ... terminal pin,
56 ... Photoelectric composite device, 64 ... Printed wiring board, 65 ... Fin, 66 ... Groove,
68 ... Dispenser, 69 ... Interposer positioning mechanism,
70 ... Interposer, 71 ... Semiconductor integrated circuit chip, 72 ... Redistribution electrode, 75 ... Space

Claims (11)

In the optical waveguide array in which a plurality of optical waveguides having a light guide for guiding light from the light incident part to the light emitting part are juxtaposed,
On one side, the light incident portions of the optical waveguides adjacent to each other among the plurality of optical waveguides, or the light incident portion and the light emitting portion are arranged at positions shifted from each other,
An optical waveguide array, wherein a cross section of the light guide path is enlarged toward a light incident end face in at least one of the light incident portions of the optical waveguides.   The optical waveguide array according to claim 1, wherein the cross section is enlarged by increasing the width of the light guide.   The optical waveguide array according to claim 2, wherein the width is linearly expanded.   2. The optical waveguide array according to claim 1, wherein positions of the light incident parts or positions of the light incident part and the light emitting part are shifted in a length direction of the adjacent optical waveguides.   The optical waveguide array according to claim 1, wherein the adjacent optical waveguides guide light in directions opposite to each other.   The light incident end surface has an inclined reflection surface, and is configured such that incident light from a light source is reflected by the inclined reflection surface and then travels through the light guide path toward the light emitting portion. The optical waveguide array described in 1.   The optical waveguide array according to claim 1, wherein a cross-sectional shape of the light guide path is a trapezoid.   The optical waveguide array according to claim 1, wherein the optical waveguide is composed of a joined body of a core and a clad.   The optical waveguide array according to claim 1, wherein the optical waveguide is formed of a polymer material.   It is a manufacturing method of the optical waveguide array given in any 1 paragraph of Claims 1-8, Comprising: The process of producing the type | mold which has a shape corresponding to the said light guide path, The said light guide path is shape | molded using the said type | mold. A method of manufacturing an optical waveguide array. Forming a photosensitive resin layer on the substrate;
Exposing the photosensitive resin layer with synchrotron radiation using a mask having a predetermined pattern;
A developing step for removing the exposed portion of the photosensitive resin layer;
Depositing metal on the removed portion of the photosensitive resin layer;
Removing a non-photosensitive portion of the photosensitive resin layer to form a master mold which is a light guide mold;
Transferring a concavo-convex shape from the master mold to form a mother mold corresponding to the master mold;
Transferring the concavo-convex shape from the mother mold, and forming the constituent material of the light guide into the shape of the light guide array,
The step of exposing the photosensitive resin layer using the mask includes the step of exposing the photosensitive resin layer by irradiating the synchrotron radiation at an angle inclined with respect to the photosensitive resin layer. Item 11. A method for manufacturing an optical waveguide array according to Item 10.

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