JP4946793B2 - Electronic device including optical wiring and optical wiring thereof - Google Patents

Description

  The present invention relates to an electronic device including an optical wiring and an optical wiring thereof, and more particularly to an electronic device including an optical wiring having a high wiring density and a small crosstalk and the optical wiring thereof.

  The signal processing speed of a semiconductor device such as an LSI is remarkably improved. As a result, the signal processing speed of the semiconductor device itself exceeds the signal transmission speed of the electrical wiring connecting the semiconductor devices (for example, between the CPU and the memory).

  For this reason, the signal processing speed of an electronic device in which a plurality of semiconductor devices are connected by electrical wiring is controlled by the transmission speed of electrical wiring that connects the semiconductor devices.

Optical wiring (optical interconnection) has attracted attention as a technology that exceeds the limit of the signal processing speed of such an electronic device (Patent Document 1).
JP-A-11-264912 Tetsuhiko Ikegami, Haruhiko Tsuchiya, Osamu Mikami: Semiconductor Photonics Engineering, Corona (1995), p.55.

(1) Electronic Device with Optical Wiring FIG. 14 is a plan view of an electronic device 6 with an optical wiring 4 that transmits a signal exchanged between the semiconductor devices 2 using an optical signal 10. FIG. 15 is a cross-sectional view of the electronic device 6 taken along the line AA ′ when viewed from the direction of the arrow.

  FIG. 16A is a plan view of the optical wiring 4 constituting the electronic device 6 shown in FIG. FIG. 16B is a cross-sectional view of the optical wiring 4 taken along the line AA ′ when viewed from the direction of the arrow.

  As shown in FIGS. 14 and 15, the electronic device 6 includes a substrate 8, a plurality of semiconductor devices 2 that are formed on the substrate 8 and process electrical signals, and a plurality of semiconductor devices 2 that are formed on the substrate 8. An optical wiring 4 constituted by the optical waveguide 12 is provided. Here, the optical waveguide 12 functions as a channel for transmitting an optical signal 10 obtained by converting a signal exchanged between the semiconductor devices 2 from electricity to light.

  Although the optical signal 10 propagates through all the optical waveguides 12 constituting the optical wiring 4, only the optical signal 10 propagating through one optical waveguide 12 is shown in FIG. 14 so as not to complicate the drawing. Described as representative. The same applies to the following drawings. As is well known, an optical waveguide is composed of a core and a clad. In the optical wiring 4, one clad is shared by the plurality of optical waveguides 12. Therefore, in FIGS. 14 to 16, reference numerals representing the respective optical waveguides are attached to the cores. The same applies to the drawings described below.

  In the optical wiring 4, as shown in FIG. 16A, the optical waveguides 12 are formed in parallel to each other. Further, as shown in FIG. 16B, the core of the optical waveguide 12 has a rectangular cross section. Furthermore, the optical waveguide 12 is formed so that the refractive indexes of the core and the clad are equal.

  However, the optical wiring 4 does not necessarily have to have the optical waveguides 12 formed in parallel with each other in all regions. For example, in order to facilitate wiring between the semiconductor devices, there may be a region where the respective optical waveguides 12 are partially bent as appropriate and become non-parallel.

  Further, the electronic device 6 includes a light emitting element 14 made of, for example, a surface emitting laser, a surface light receiving element 16, and a 45 ° mirror 18. The light emitting element 14 and the light receiving element 16 are each driven by the semiconductor device 2.

  Here, the light emitting element 14 and the light receiving element 16 are mounted together with the semiconductor device 2 on the substrate 20 on which electrical wiring is provided. The substrate 20 has a via hole (not shown) through which the optical signal 10 passes.

  Further, the substrate 20 to which the electrical wiring is applied is held by the support 21 and the optical wiring 4 and is fixed with a gap between the substrate 20 and the substrate 8. A 45 ° mirror 18 is disposed in the gap, and optically couples the light emitting element 14 or the light receiving element 16 and the optical waveguide 12.

  Signal transmission between the semiconductor devices 2 is performed as follows.

  First, an electrical signal generated by one semiconductor device 2 is converted into an optical signal 10 by the light emitting element 14. The optical signal 10 converted into light by the light emitting element 14 is radiated toward the substrate 8, and its traveling direction is changed by the 45 ° mirror 18 and enters the optical waveguide 12. The traveling direction of the optical signal 10 propagated through the optical waveguide 12 is changed by the 45 ° mirror 18 in the direction perpendicular to the substrate 8 and is incident on the planar light receiving element 16. The optical signal 10 incident on the light receiving element 16 is converted into an electric signal and received by the other semiconductor device 2.

In this way, in an electronic device provided with optical wiring, signal transmission between semiconductor devices is performed.
(2) Speeding up of an electronic device provided with optical wiring and its problem (in an electronic device provided with optical wiring) Improvement of transmission speed between semiconductor devices is the number of optical waveguides 12 constituting the optical wiring 4. It becomes possible by increasing.

  In long-distance optical transmission, wavelength multiplexing technology that transmits a large number of optical signals having different wavelengths through a single optical fiber has been effective in improving the transmission speed.

  However, it is difficult to apply this optical multiplexing technology to the optical wiring technology. The optical wiring 4 is formed on a substrate 8 whose height and width are about 20 to 30 cm at most. On such a small substrate, it is difficult to arrange optical components (multiplexer, demultiplexer, etc.) for wavelength multiplexing for each semiconductor device.

  For this reason, in the optical wiring technology, for example, as shown in FIG. 14, an optical wiring 4 provided with a large number of optical waveguides 12 is used to spatially multiplex optical signals to improve the transmission speed.

  Therefore, in order to improve the signal transmission speed between semiconductor devices, it is necessary to increase the number of transmission channels by narrowing the interval between the optical waveguides 12. For example, in the most general optical wiring 4, the interval between the optical waveguides 12 is 250 μm.

  However, if the interval between the optical waveguides is further narrowed, first, the crosstalk is remarkably increased between the adjacent optical waveguides. When the distance between the optical waveguides is further reduced, the optical signal 10 is finally transferred to the adjacent optical waveguide as shown in FIG.

  Under such circumstances, it is no longer possible to transmit optical signals between semiconductor devices. For this reason, it is difficult to greatly reduce the distance between the optical waveguides 12 in the optical wiring from the current 250 μm. As described above, the conventional method of simply reducing the distance between the optical waveguides to improve the transmission speed with the structure of the optical wiring has reached the limit.

  Accordingly, an object of the present invention is to make it possible to increase the density of optical wiring by constructing an optical waveguide structure in which the crosstalk between adjacent optical waveguides does not increase even if the interval between the optical waveguides 12 is narrowed. It is to improve the signal processing speed of an electronic device that performs signal transmission between semiconductor devices.

(First side)
In order to achieve the above object, according to a first aspect of the present invention, there is provided a substrate, a plurality of semiconductor devices formed on the substrate for processing electrical signals, and signals exchanged between the semiconductor devices. Includes an optical wiring composed of a plurality of optical waveguides formed on the substrate for transmitting an optical signal converted from electricity to light, and the optical wiring is formed in parallel with each other. In the electronic device including the region, the core of the optical waveguide is formed in a rectangular cross section in the region, and the first and second optical waveguides composed of the adjacent optical waveguides are refracted by the core and the clad. The ratio is equal, and one or both of the width and thickness of the cross section is different between the first and second optical waveguides.

  According to the first aspect, since one or both of the width and thickness of the adjacent optical waveguides are different, the propagation constants between the optical waveguides are different. Therefore, according to the first aspect, since the crosstalk between adjacent optical waveguides can be reduced even if the interval between the optical waveguides constituting the optical wiring is reduced, the density of the optical wiring can be increased. The signal processing speed of an electronic device that performs signal transmission between semiconductor devices by optical wiring can be dramatically improved.

(Second aspect)
In order to achieve the above object, according to a second aspect of the present invention, in the first aspect, either one or both of the width and the thickness is made different, whereby the first and second light guides are used. The crosstalk between the waveguides is -30 dB or less.

(Third aspect)
In order to achieve the above object, according to a third aspect of the present invention, there is provided a substrate, first and second semiconductor devices formed on the substrate for processing electrical signals, and the first and second semiconductor devices. An optical wiring configured by a plurality of optical waveguides formed on the substrate for transmitting an optical signal obtained by converting a signal exchanged between two semiconductor devices from electricity to light, the optical wiring comprising: In the electronic device including a region in which the optical waveguides are formed in parallel to each other, a cross section of the core of the optical waveguide is formed in a rectangular shape in the region, and the optical wiring has a refractive index of the core and the cladding. First and second optical waveguides consisting of the optical waveguides that are equal and adjacent to each other are alternately arranged, and either one of the width and thickness of the cross section between the first and second optical waveguides or Both are configured differently, A first optical waveguide transmits the optical signal transmitted from the first semiconductor device to the second semiconductor device, and the second optical waveguide transmits the first optical device from the second semiconductor device. The optical signal transmitted to the semiconductor device is transmitted.

According to the third aspect, since the optical signal propagating in the same direction propagates through the optical waveguide having the same core width and thickness, the skew generated in the optical wiring related to the first side (between the optical waveguides). The difference in the arrival time of the optical signal in (1) can be eliminated.
(Fourth aspect)
In order to achieve the above object, according to a fourth aspect of the present invention, there is provided a substrate, a plurality of semiconductor devices formed on the substrate for processing electrical signals, and signals exchanged between the semiconductor devices. Includes an optical wiring composed of a plurality of optical waveguides formed on the substrate for transmitting an optical signal converted from electricity to light, and the optical wiring is formed in parallel with each other. In the electronic device including the region, the core of the optical waveguide is formed in a rectangular cross section in the region, and the first and second optical waveguides composed of the adjacent optical waveguides are refracted by the core and the clad. A plurality of short optical waveguides having the same ratio and different in one or both of the width and thickness of the cross section are connected in cascade, and the first and second optical waveguides are respectively configured and mutually connected. Adjacent short light Waveguides, either or both of the width and thickness of the cross section are different from each other.

  According to the fourth aspect, since the optical waveguide is formed by cascading short optical waveguides having different one or both of the width and thickness of the core cross section, the optical waveguide density of the optical wiring composed of the optical waveguide is reduced. At the same time, it is easy to construct an optical wiring without skew (difference in arrival time of optical signals between optical waveguides). Therefore, according to the fourth aspect, the signal processing speed of the electronic device that performs signal transmission between the semiconductor devices by the optical wiring is dramatically improved, and at the same time, the signal processing without skew is realized in the electronic device. It becomes easy.

(5th side)
In order to achieve the above object, according to a fifth aspect of the present invention, there is provided the short optical waveguide according to the fourth aspect, wherein the short optical waveguide differs in any one or both of the width and thickness of the cross section. A value obtained by summing the lengths of is equal between the first and second optical waveguides.

  According to the fifth aspect, it is possible to realize an electronic device including an optical wiring that has a remarkably high signal processing speed and has no skew (difference in arrival time of optical signals between optical waveguides). .

  In the present invention, either or both of the width and the thickness of the core cross section of the adjacent optical waveguides are made different so that the propagation constants of the adjacent optical waveguides are made different so that they are adjacent even if the interval between the optical waveguides is narrowed. Prevent crosstalk between optical waveguides from becoming large. For this reason, according to this invention, the density of the optical waveguide which comprises an optical wiring can be made high.

  Therefore, according to the present invention, it is possible to dramatically improve the signal processing speed of an electronic device that performs signal transmission between semiconductor devices through an optical wiring.

  In the present invention, the optical waveguide is configured by cascading short optical waveguides having different one or both of the width and thickness of the core cross section. For this reason, the optical waveguide density of the optical wiring composed of the optical waveguide can be increased, and at the same time, the optical wiring without skew (difference in arrival time of the optical signal between the optical waveguides) can be configured. .

  Therefore, according to the present invention, it is possible to dramatically improve the signal processing speed of an electronic device that performs signal transmission between semiconductor devices using an optical wiring, and to perform signal transmission between semiconductor devices without skew. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof. Note that even if the drawings are different, corresponding parts are denoted by the same reference numerals, and description thereof is omitted.

(Embodiment 1)
In the present embodiment, the optical wiring in which the crosstalk does not increase even if the interval between the optical waveguides is narrowed by making either one or both of the width and the thickness of the core cross section of the adjacent optical waveguide different. The present invention relates to an electronic device provided.

(1) Device Configuration The configuration of the electronic device according to the present embodiment is almost the same as that of the electronic device (related technology) shown in FIGS.

  However, as shown in FIG. 6, the optical wiring 24 constituting the electronic device according to the present embodiment has a width W1, W2 and a thickness D1, D2 of the cross section of the core between the adjacent optical waveguides 26, 28. 14 differs from the electronic device 6 shown in FIG. 14 and FIG. 15 in that either one or both are different (in FIG. 6, the widths W1 and W2 of the cross section of the core are different). 6A is a plan view of the optical wiring 24, and FIG. 6B is a cross-sectional view taken along the line AA ′ of FIG. 6A viewed from the direction of the arrow. .

  Here, the configuration of the cores of the first and second optical waveguides 26 and 28 is such that either one or both of the width and thickness of the cross section of the cores of the first and second optical waveguides 26 and 28 are different. Therefore, it is preferable that the crosstalk between the first and second optical waveguides 26 and 28 is set to −30 dB or less.

  In addition, the configuration of the cores of the first and second optical waveguides 26 and 28 is made by changing either one or both of the width and thickness of the cross section of the cores of the first and second optical waveguides 26 and 28. More preferably, the crosstalk between the first and second optical waveguides 26 and 28 is set to -50 dB or less. Furthermore, the configuration of the cores of the first and second optical waveguides 26 and 28 is such that either one or both of the width and thickness of the cross section of the cores of the first and second optical waveguides 26 and 28 are different. Therefore, it is most preferable that the crosstalk between the first and second optical waveguides 26 and 28 is −70 dB or less.

  However, if the crosstalk is made too small, the cross-sectional asymmetry of the cores of the first and second optical waveguides 26 and 28 is increased, and the characteristics (for example, transmission speed) of the first and second optical waveguides 26 and 28 are increased. Therefore, it is not preferable to make the crosstalk smaller than necessary. From such a viewpoint, the lower limit of crosstalk is preferably −120 dB or more, more preferably −100 dB or more, still more preferably −80 dB or more, and most preferably −40 dB or more.

(2) Principle First, the reason why crosstalk increases when the distance between the optical waveguides becomes narrow when the width and thickness of the core sections of adjacent optical waveguides are equal. In the following description, it is assumed that the relative refractive index difference between the core and the clad of the adjacent optical waveguides is the same, and propagates through two optical waveguides 30 and 32 arranged in parallel and close as shown in FIG. The optical signal propagates while reciprocating alternately between these adjacent optical waveguides.

Here, when the power of the optical signal in the optical waveguide 30 on which the optical signal 10 is incident is P ₁ (z) and the power of the signal light in the other optical waveguide 32 is P ₂ (z), the optical waveguide 30, When the propagation constants of 32 are equal, the optical signal powers P ₁ (z) and P ₂ (z) alternately increase as shown in FIG. 2 with respect to the position coordinate z in the propagation direction. Here, the vertical axis in FIG. 2 represents the power of the standardized optical signal. The horizontal axis is the position coordinate z in the light propagation direction.

When the width and thickness of the core cross-sections of the adjacent optical waveguides are equal, the propagation constants β ₁ and β ₂ of both optical waveguides are equal. In this case, as shown in FIG. 2, the optical signal (P ₁ (z)) propagating through one optical waveguide gradually changes to the other optical waveguide (P ₂ (z)), and the entire optical signal eventually becomes the other optical waveguide. Propagates through the optical waveguide. The optical signal completely transferred to the other side is gradually transferred to the original optical waveguide, and the entire optical signal is propagated again through the original optical waveguide (for example, Non-Patent Document 1).

  The optical signal 10 repeats such a reciprocating motion between the two optical waveguides 30 and 32 that are close to each other.

  The half of the period of this reciprocation, that is, the distance at which power is completely transferred from one optical waveguide to the other optical waveguide is called a coupling length L (see FIG. 2). This coupling length becomes shorter as the two optical waveguides are closer to each other.

  As an example, in an optical waveguide in which the relative refractive index difference between the core and the clad is 0.5% and the width of one core is 3 μm and the thickness is 3 μm, when the interval is 100 μm to 200 μm, the coupling length is 1 km or more. Long range. Therefore, in an optical wiring having a length of 20 to 30 cm at most, the transition of the optical power between the optical waveguides, that is, the crosstalk becomes less serious by separating the adjacent optical waveguides 12 by 100 μm to 200 μm.

  However, when the distance between the optical waveguides is narrowed to 100 μm or less, the coupling length approaches the length of the optical waveguides constituting the optical wiring. As a result, the shift of optical power from the optical waveguide (one optical waveguide 30) into which the signal light has entered (that is, the crosstalk) to the other optical waveguide 32 becomes large and cannot be ignored.

  Further, when the interval between the optical waveguides is reduced to about 20 to 30 μm, the coupling length is reduced to about 30 cm. Under such a situation, the optical signal moves between the adjacent optical waveguides 30 and 32, and the optical wiring can no longer perform its function.

On the other hand, in the present embodiment, one or both of the width W1, W2 and the thickness D1, D2 of the core cross section are made different between the adjacent optical waveguides 26, 28. FIG. 6 shows an example in which the core widths W1 and W2 are different between the adjacent optical waveguides 26 and 28. FIG. In this case, the propagation constants β ₁ and β ₂ of both optical waveguides 26 and 28 have different values.

  If the propagation constants are different between adjacent optical waveguides, the optical power transfer between the optical waveguides is incomplete.

  FIG. 3 is a diagram for explaining a change in power of light propagating through the optical waveguides 30 and 32 when the propagation constants of adjacent optical waveguides are different. The vertical axis represents the power of the standardized optical signal. The horizontal axis is the position coordinate z in the light propagation direction.

As shown in FIG. 3, when the propagation constants of the adjacent optical waveguides 30 and 32 are different, the power of the optical signal propagating through the optical waveguide into which the signal light is incident (one optical waveguide 30, see FIG. 1) is represented by P ₁ ( z) does not become zero even at the coupling length L. On the other hand, the power of the signal light transferred to the (other) optical waveguide 32 is P ₂ (z), which is the optical signal light intensity when the signal light 10 is first incident on the optical waveguide 30 even in the coupling length L ( = 1) does not increase (P ₂ <1).

Even if the coupling length becomes the same as or shorter than the length of the optical waveguide as a result of increasing the density of the optical waveguide, the core between the adjacent optical waveguides 26 and 28, for example, as shown in FIG. It has been shown that if one or both of the width and thickness of the cross section are made different, the transition of the optical power between the adjacent optical waveguides 26 and 28 can be reduced. The crosstalk in this case is at most only the optical power (P ₂ (z)) transferred to the other optical waveguide 32 in the coupling length L.

  Therefore, even if the optical wiring 4 is densified, the crosstalk between the optical waveguides is reduced by making either or both of the width and the thickness of the core cross section between the adjacent optical waveguides 26 and 28 different. It becomes possible.

  In the example shown in FIG. 3, since the asymmetry of the width or thickness of the core cross section is not so large, the optical power transferred to the adjacent optical waveguide is still large. However, if the asymmetry of the width or thickness of the core cross section is appropriately increased, the value of optical power transferred to the adjacent optical waveguide, that is, the value of crosstalk can be reduced to a level that can be ignored in practice.

  For example, if the relative refractive index difference between the core and the clad is 0.5%, the width of one core is 3 μm and the thickness is 3 μm, and the width of the other core is 2 μm and the thickness is 3 μm, the distance between the optical waveguides The crosstalk between adjacent optical waveguides becomes -30 dB or less even when the value approaches 20 μm.

As described above, according to the present embodiment, even if the distance between the optical waveguides 26 and 28 constituting the optical wiring 4 is reduced, the crosstalk between adjacent optical waveguides can be reduced. Densification is possible, and the signal processing speed of an electronic device that performs signal transmission between semiconductor devices by optical wiring can be dramatically improved.
(Embodiment 2)
The electronic device according to the present embodiment is an electronic device in which the skew (difference in arrival time of optical signals between optical waveguides) that is a problem in the electronic device 22 according to the first embodiment is eliminated.

  FIG. 7 is a plan view for explaining the electronic device 34 in the present embodiment.

  The configuration of the electronic device 34 according to the present embodiment is almost the same as the electronic device shown in the first embodiment. That is, in the electronic apparatus 34 according to the present embodiment, as shown in FIG. 7, the first and second optical waveguides 26 and 28 having the same refractive index of the core and the clad and made of adjacent optical waveguides are alternately arranged. The first and second optical waveguides 26 and 28 are configured such that one or both of the width and thickness of the cross section are different.

  However, in the electronic device 34 according to the present embodiment, the first optical waveguide 26 is transmitted from the first semiconductor device 36 to the second semiconductor device 38 (via the light emitting element 14 and the light receiving element 16). The optical signal 40 is transmitted, and the second optical waveguide 28 transmits the optical signal 42 transmitted from the second semiconductor device 38 to the first semiconductor device 36 (via the light emitting element 14 and the light receiving element 16). Features a point.

  In the first embodiment described above, either or both of the cross-sectional width and thickness of the adjacent optical waveguides 26 and 28 are made different so that their propagation constants do not match. In such a case, a difference occurs in the speed of the signal light propagating through the adjacent optical waveguides 26 and 28. Further, as shown in FIG. 4, the electronic device 22 according to the first embodiment is configured such that adjacent optical waveguides transmit optical signals in the same direction except for the optical waveguides 86 and 88 adjacent in the center. Yes. FIG. 4 is a plan view for explaining the configuration of the electronic device 22 according to the first embodiment.

  For this reason, in the electronic device 22 according to the first embodiment, a skew occurs in which the time for the optical signal to reach the second semiconductor device 38 from the first semiconductor device 36 differs between the optical waveguides.

  In contrast, in the present embodiment, as described above, the first optical waveguide 26 that transmits the optical signal 40 from the first semiconductor device 36 to the second semiconductor device 38 is, for example, as shown in FIG. In addition, they are all constituted by wide optical waveguides. On the other hand, the second optical waveguide 28 that transmits the optical signal 42 from the second semiconductor device 38 to the first semiconductor device 36 is constituted by a narrow optical waveguide 42 as shown in FIG. 7, for example. .

  Thus, if the core shapes of the optical waveguides that transmit optical signals from one semiconductor device to the other semiconductor device are the same, the propagation constants of these optical waveguides become equal, and no skew occurs. On the other hand, since the core shapes are different between adjacent optical waveguides, the crosstalk is reduced, and the optical wiring can be densified.

  Therefore, according to the present embodiment, the skew (difference in arrival time of the optical signal between the optical waveguides) generated in the optical wiring according to the first embodiment can be eliminated.

(Embodiment 3)
As in the first embodiment, the electronic device according to the present embodiment relates to an electronic device including an optical wiring that prevents crosstalk from increasing even if the interval between the optical waveguides is reduced.

  The electronic device according to this embodiment is different from the electronic device shown in Embodiment 1 in the configuration of the optical wiring. The other points are the same as those of the electronic device 22 according to the first embodiment. By adopting such an optical wiring, it is possible to easily solve the skew even if the light transmission direction is not reversed between the adjacent optical waveguides as in the second embodiment. However, this point will be described in detail in Embodiment 4 below.

  FIG. 8 is a diagram for explaining an example of the optical wiring 44 according to the present embodiment. FIG. 8A is a plan view. FIG. 8B is a cross-sectional view of the cross section taken along the line AA ′ shown in FIG.

  As shown in FIG. 8B, also in this embodiment, the cores of the optical waveguides 46 and 48 have a rectangular cross section.

  Here, in the electronic device 44 according to the present embodiment, as shown in FIG. 8A, the first and second optical waveguides 46 and 48 composed of adjacent optical waveguides have the same refractive indexes of the core and the clad. In addition, a plurality of optical waveguides 50 and 52 (hereinafter, referred to as “core widths W1 and W2 in the example of FIG. 8) having different one or both of the width W1 and W2 and the thicknesses D1 and D2 of the cross section of the core. A short optical waveguide) is connected in cascade. Here, the cascade connection means that the optical waveguides are connected in the light propagation direction.

  Further, in the electronic device of the present embodiment, the short optical waveguides 50 and 52 that constitute the first and second optical waveguides 46 and 48, respectively, are adjacent to each other in the width W1, W2 and thickness of the core cross section. One or both of D1 and D2 (in the example of FIG. 8, the core widths W1 and W2) are different.

  By configuring in this way, the short optical waveguides 50 and 52 constituting the first and second optical waveguides 46 and 48 and adjacent to each other are either or both of the width and thickness of the cross section of the core (FIG. 8). In this example, the core widths W1 and W2) are different. Accordingly, since the propagation constants of the adjacent short optical waveguides 50 and 52 have different values, the light transition between the adjacent short optical waveguides 50 and 52 is caused by the length of the short optical waveguides 50 and 52. Even a bond length or more is negligible. For this reason, the signal light 10 is only slightly transferred between the first and second optical waveguides 46 and 48 in which the short optical waveguides 50 and 52 are connected in cascade.

  For example, the relative refractive index difference between the core and the clad of the short optical waveguides 50 and 52 is 0.5%, the core width of the short optical waveguide 50 is 3 μm, the thickness is 3 μm, and the core width of the short optical waveguide 52 is When the thickness is 3 μm, the crosstalk of the short optical waveguides 50 and 52 is −30 dB or less even when the distance between the first and second optical waveguides 50 and 52 approaches 20 μm.

  Therefore, according to the present embodiment, even if the distance between the optical waveguides 46 and 48 constituting the optical wiring 44 is reduced, the crosstalk between the adjacent optical waveguides can be reduced. Therefore, the signal processing speed of an electronic device that performs signal transmission between semiconductor devices through optical wiring can be dramatically improved.

(Embodiment 4)
The electronic device according to the present embodiment is an electronic device in which the skew (difference in arrival time of optical signals between optical waveguides) in the electronic device according to the third embodiment is eliminated.

  The configuration of the electronic device according to the present embodiment is substantially the same as that of the electronic device according to the third embodiment.

  However, the optical wiring 44 of the electronic device according to the present embodiment has short optical waveguides 50 and 52 in which one or both of the widths W1 and W2 and the thicknesses D1 and D2 of the core sections of the optical waveguides 46 and 48 are different. The value obtained by taking the sum of the lengths of the short optical waveguides is equal between the first and second optical waveguides 46 and 48.

  For example, in the electronic device including the optical wiring 44 shown in FIG. 8, the value L1 obtained by summing the lengths of the wide short optical waveguides 50 in the first optical waveguide 46 is the second optical waveguide 48. The sum of the lengths of the short optical waveguides 52 having the same width is equal to the value L2 obtained by taking the sum of the lengths of the short optical waveguides 50 having the wider width (L1 = L2). The obtained value M1 is equal to the value M2 obtained by taking the sum of the lengths of the narrow short optical waveguides 52 in the second optical waveguide 48 (M1 = M2).

The time T ₁ required for the optical signal 10 to propagate from end to end of the first optical waveguide 46 is required for the optical signal 10 to propagate through all the short optical waveguides 50 constituting the first optical waveguide 46. and the time _{t 11,} the optical signal 10 is a sum of the time _{t 12} required to propagate all the short optical waveguides 52 constituting the first optical waveguide 46 _{(i.e., T 1 = t 11 + t} 12). The time required for the optical signal 10 to propagate through the transition region 54 between the short optical waveguides 50 and 52 is considered to be sufficiently shorter than the time required for the optical signal 10 to propagate through the short optical waveguides 50 and 52. I ignored it.

On the other hand, the time T ₂ required for the optical signal 10 to propagate from end to end of the second optical waveguide 48 is such that the optical signal 10 propagates through all the short optical waveguides 50 constituting the second optical waveguide 48. to the time required _{t 21,} the optical signal 10 is a sum of the time _{t 22} required to propagate all the short optical waveguides 52 constituting the second optical waveguide 48 _{(i.e., T 2 = t 21 + t} 22 ).

By the way, the time t ₁₁ required for the optical signal 10 to propagate through all the short optical waveguides 50 having a large core width constituting the first optical waveguide 46 is short optical light having a wide width in the first optical waveguide 46. It is determined by a value L1 obtained by summing the lengths of the waveguides 50 and a propagation constant β1 of the short optical waveguide 50.

That is, when the angular frequency of the signal light 10 is ω, t ₁₁ = L1 × β1 / ω.

Similarly, the time t ₁₂ required for the optical signal 10 to propagate through all the short optical waveguides 52 having a large core width constituting the first optical waveguide 46 is t ₁₂ = M1 × β2 / ω.

Accordingly, the time T ₁ required for the optical signal 10 to propagate from end to end of the first optical waveguide 46 is T ₁ = t ₁₁ + t ₁₂ = L1 × β1 / ω + M1 × β2 / ω.

Similarly, the time T ₂ required for the optical signal 10 to propagate from end to end of the second optical waveguide 48 is T ₂ = t ₂₁ + t ₂₂ = L2 × β1 / ω + M2 × β2 / ω. .

  Here, as described above, since L1 = L2 and M1 = M2, T1 = T2.

That is, the time T ₁ required for the optical signal 10 to propagate from end to end of the first optical waveguide 46 is the time T ₂ required for the optical signal 10 to propagate from end to end of the first optical waveguide 48. Is equal to

  Therefore, according to the present embodiment, it is possible to eliminate the skew (difference in arrival time of the optical signal between the optical waveguides) that occurs in the optical wiring according to the first embodiment.

  This embodiment includes an optical wiring in which crosstalk does not increase even if the interval between the optical waveguides is narrowed by making either one or both of the width and the thickness of the core cross section of the adjacent optical waveguide different. This relates to an electronic device.

(1) Device Configuration FIG. 4 is a plan view of an electronic device 22 provided with an optical wiring 24 that transmits signals exchanged between the semiconductor devices 2 using light 10. FIG. 5 is a cross-sectional view taken along the line AA ′ of FIG. 4 as viewed from the direction of the arrow.

  FIG. 6A is a plan view of the optical wiring 24. FIG. 6B is a cross-sectional view of the cross section taken along the line AA ′ in FIG.

  4 and 5, the electronic device 22 includes, for example, a substrate 8 made of any one of quartz, glass, silicon, ceramic, and resin, and a CPU or memory formed on the substrate 8, for example. And a plurality of semiconductor devices 2 for processing electrical signals, and an optical wiring 24 composed of a plurality of optical waveguides 26 and 28 formed on the substrate 8. Here, the optical waveguides 26 and 28 function as a channel for transmitting an optical signal 10 obtained by converting a signal exchanged between the semiconductor devices 2 from electricity to light.

  The optical waveguides 26 and 28 in the present embodiment are formed of polyimide resin (Hitachi Chemical Industry, trade name OPI). However, the material for forming the optical waveguides 26 and 28 is not limited to a specific material, and may be any of quartz, glass, silicon, and resin (epoxy resin, acrylic resin, polyimide resin, etc.), for example. May be.

  In the optical wiring 24, as shown in FIG. 6A, first and second optical waveguides 26 and 28 are formed in parallel to each other. The interval between the optical waveguides 26 and 28 is 20 μm.

  Further, as shown in FIG. 6B, the cross sections of the cores of the first and second optical waveguides 26 and 28 are formed in a rectangular shape. Here, the width W1 of the core of the first optical waveguide 26 is 3 μm, and the thickness D1 thereof is 3 μm. Further, the width W2 of the core of the second optical waveguide 28 is 2 μm, and the thickness D2 thereof is 3 μm. The first and second optical waveguides 26 and 28 have the same refractive index of the core and the clad, and the relative refractive index difference between the core and the clad is 0.5%.

  The electronic device 22 further includes a light emitting element 14 made of a surface emitting laser, a surface light receiving element 16, and a 45 ° mirror 18 (see FIGS. 4 and 5). The semiconductor device 2 includes a drive circuit for the light emitting element 14 and the light receiving element 16.

  The light emitting element 14 and the light receiving element 16 are mounted together with the semiconductor device 2 on a silicon substrate 20 on which electrical wiring is provided. A via hole (not shown) through which the optical signal 10 emitted from the light emitting element 14 passes or the optical signal 10 incident on the light receiving element 16 passes is opened in the silicon substrate 20.

  Moreover, the board | substrate 20 to which electric wiring was given is hold | maintained by the support body 21 and the optical wiring 4, and is fixed in the state which opened the clearance gap between the board | substrates 8, as shown in FIG. A 45 ° mirror 18 is disposed in the gap, and the 45 ° mirror 18 optically couples the light emitting element 14 or the light receiving element 16 and the optical waveguide 12.

  In the electronic device 22 configured as described above, the crosstalk of the optical wiring 24 is −30 dB or less.

  That is, in the electronic device 22 of this embodiment, the distance between the optical waveguides 26 and 28 constituting the optical wiring 24 is 20 μm, which is an order of magnitude narrower than the optical waveguide spacing 100 to 200 μm of the conventional optical wiring. The crosstalk between 26 and 28 is as low as −30 dB or less so that there is no practical problem.

(2) Operation The electronic device 24 in this embodiment operates as follows.

  First, an electrical signal generated by one semiconductor device 2 is converted into an optical signal 10 by the light emitting element 14. As shown in FIG. 5, the optical signal 10 photoelectrically converted by the light emitting element 14 is radiated toward the substrate 8, the traveling direction thereof is changed by the 45 ° mirror 18, and the light signal 10 enters the optical waveguides 26 and 28. The optical signal 10 propagates through the optical waveguides 26, 28, the traveling direction is changed in a direction perpendicular to the substrate 8 by the 45 ° mirror 18, and enters the planar light receiving element 16. The optical signal 10 incident on the light receiving element 16 is converted into an electric signal and received by the other semiconductor device 2.

  Here, since the optical waveguides 26 and 28 have different core widths of 2 μm and 3 μm, almost no power transfer occurs between the optical waveguides 26 and 28, and the crosstalk is −30 dB. It is only a small value that does not cause any practical problems.

  The electronic apparatus according to the present embodiment is an electronic apparatus that eliminates a skew (difference in arrival time of an optical signal between optical waveguides) that is a problem in the electronic apparatus 22 according to the first embodiment.

  FIG. 7 is a plan view illustrating the configuration of the electronic device 34 according to the present embodiment.

  The configuration of the electronic device 34 according to the present embodiment is almost the same as the electronic device shown in the first embodiment.

  However, in the electronic device 34 according to the present embodiment, the first optical waveguides 26 arranged alternately are arranged from the first semiconductor device 36 to the second semiconductor device 38 (via the light emitting element 14 and the light receiving element 16). The second optical waveguides 42 that transmit the optical signals 40 transmitted to and alternately arranged from the second semiconductor device 38 to the first semiconductor device 36 (via the light emitting element 14 and the light receiving element 16). It is characterized in that the transmitted optical signal 42 is transmitted.

  In the electronic device 22 according to the first embodiment illustrated in FIG. 4, the light emitting element 14 and the light receiving element 16 are not mixed with each other and are disposed on the right half or the left half of the substrate 20 on which the semiconductor device 2 is mounted. . Therefore, for example, a signal generated by the upper semiconductor device 2 is converted into the optical signal 10 and propagates through both the optical waveguide 26 having a large core width and the optical waveguide 28 having a narrow core width, and the lower semiconductor device. 2 is transmitted.

  The first and second optical waveguides 24 and 26 have different core widths. For this reason, the propagation constants of the first and second optical waveguides 26 and 28 are different. Therefore, there is a difference between the arrival time of the optical signal propagating through the first optical waveguide 26 and going from the upper side to the lower side, and the arrival time of the optical signal propagating through the second optical waveguide 28 and going from the upper side to the lower side. End up. That is, skew occurs.

On the other hand, in the electronic apparatus 34 of this embodiment shown in FIG. 7, the light emitting elements 14 and the light receiving elements 16 are alternately arranged on the substrate 20 on which the semiconductor devices 36 and 38 are mounted. Therefore, for example, an optical signal 1 obtained by photoelectrically converting a signal generated by the upper semiconductor device 36.
All of the signals 40 propagate through the optical waveguide 26 having a wide core and are transmitted toward the lower semiconductor device 38.

  Accordingly, the optical signal 40 traveling from the upper side to the lower side of the electronic device 34 propagates through the wide optical waveguide 26 having the same propagation constant. Similarly, the optical signal 42 directed from the lower side to the upper side of the electronic device 34 propagates through the narrow optical waveguide 28 having the same propagation constant.

  For this reason, in the electronic device 34 of the present embodiment, the skew in which the time that the optical signal reaches differs between the optical waveguides does not occur. Further, since the core shapes are different between adjacent optical waveguides, the crosstalk does not increase even if the interval between the optical waveguides is reduced. Therefore, the optical wiring can be densified.

  As in the first embodiment, the electronic device according to the present embodiment relates to an electronic device including an optical wiring that prevents crosstalk from increasing even if the interval between the optical waveguides is narrowed.

However, according to the electronic apparatus of this embodiment, even if the light transmission direction is not reversed between adjacent optical waveguides as in the second embodiment, the difference in arrival time of optical signals between the optical waveguides, that is, the skew. (1) Configuration The electronic device according to the present embodiment is different from the electronic device shown in the first embodiment in the configuration of the optical wiring. The other points are the same as those of the electronic device 22 according to the first embodiment.

  FIG. 8 is a diagram illustrating the configuration of the optical wiring 44 according to the present embodiment. FIG. 8A is a plan view. FIG. 8B is a cross-sectional view of the cross section taken along the line AA ′ of FIG.

  As shown in FIG. 8B, also in this embodiment, the cores of the optical waveguides 46 and 48 are formed in a rectangular cross section.

  The optical waveguides 46 and 48 in the present embodiment are also formed of polyimide resin (Hitachi Chemical Industries, trade name OPI), similarly to the optical wiring 24 according to the first embodiment. However, the material for forming the optical waveguides 26 and 28 is not limited to a specific material, and may be any one of, for example, quartz, glass, silicon, and resin (epoxy resin, acrylic resin, polyimide resin). Also good.

  Here, as shown in FIG. 8A, the electronic device of the present embodiment has the first and second optical waveguides 46 and 48 formed of adjacent optical waveguides having the same refractive index of the core and the cladding, and A plurality of optical waveguides 50 and 52 (hereinafter referred to as short optical waveguides) having different cross-sectional widths W1 and W2 of a core formed in a rectangular shape are connected in cascade.

  The first short optical waveguide 50 has a width of 3 μm and a thickness of 3 μm. On the other hand, the second short optical waveguide 52 has a width of 2 μm and a thickness of 3 μm. The distance between adjacent first and second optical waveguides 46 and 48 is 20 μm. The relative refractive index difference between the first and second optical waveguides 46 and 48 is 0.5%.

  Further, in the electronic device of the present embodiment, the short optical waveguides 50 and 52 constituting the first and second optical waveguides 46 and 48 and adjacent to each other are either one of the width and thickness of the cross section of the core, or Both are different (in the example of FIG. 8, the core widths w 1 and w 2) are different.

  As described above, the short optical waveguides 50 and 52 constituting the first and second optical waveguides 46 and 48 and adjacent to each other have different core cross-sectional widths. For this reason, the propagation constants β1 and β2 of the adjacent short optical waveguides 50 and 52 have different values.

  Accordingly, the transition of light between the adjacent short optical waveguides 50 and 52 does not become a large value even if the length of the short waveguides 50 and 52 is equal to or longer than the coupling length. For example, the crosstalk between the short optical waveguides 46 and 48 in this embodiment is −30 dB or less.

  For this reason, there is very little transfer of signal light between the first and second optical waveguides 46 and 48 in which a plurality of short optical waveguides 50 and 52 are connected in cascade.

  Therefore, according to this embodiment, even if the interval between the optical waveguides 46 and 48 constituting the optical wiring 44 is narrowed, the crosstalk between the adjacent optical waveguides 46 and 48 can be reduced. The density can be increased, and the signal processing speed of an electronic device that performs signal transmission between semiconductor devices by optical wiring can be improved.

  Furthermore, in the present embodiment, the sum of the optical waveguide lengths of the two short optical waveguides 50 constituting the first optical waveguide 46 (l1 + l3) and the width constituting the second optical waveguide 48 are increased. The sum of the optical waveguide lengths of the two wide short optical waveguides 50 (l6 + l8) is equal (for l1, l3, l6, and l8, see FIG. 8 (a)). In addition, the sum of the optical waveguide lengths of the two short optical waveguides 52 that form the first optical waveguide 46 (l 2 +14) and the two short optical waveguides that form the second optical waveguide 48. The sum of the optical waveguide lengths (l5 + l7) of the optical waveguide 52 is equal (see FIG. 8A for l2, l4, l5, and l7).

  Since the short optical waveguides 50 and 52 have different core widths, their propagation constants are different. Therefore, the propagation speed of light in each short optical waveguide is different. However, as described above, the sum of the optical waveguide lengths of the short optical waveguide 50 having a large core width constituting the first optical waveguide 46 (l1 + l3) is the wide core width configuring the second optical waveguide 48. It is equal to the sum of the optical waveguide lengths of the short optical waveguide 50 (l6 + 18). In addition, the sum of the optical waveguide lengths of the short optical waveguide 52 having the narrow core width constituting the first optical waveguide 46 (l2 + 14) is the sum of the short optical waveguide 52 having the narrow core width configuring the second optical waveguide 48. It is equal to the sum of the optical waveguide lengths l5 + l7).

  For this reason, the time required for the signal light to propagate through the first optical waveguide is equal to the time required for the signal light to propagate through the second optical waveguide. That is, no skew occurs in the electronic apparatus according to the present embodiment. Since the transition region 54 of the short optical waveguide 50 and the short optical waveguide 52 is shorter than the short optical waveguides 50 and 52, the time of light propagating through the transition region 54 is ignored in the above description.

(2) Operation The operation of the electronic apparatus according to the present embodiment is basically the same as that of the electronic apparatus according to the first embodiment.

  However, the difference is that the signal light alternately propagates through the short optical waveguides 50 and 52 having different core widths.

  The electronic device according to this embodiment relates to an electronic device provided with an optical wiring in which optical waveguides are formed in multiple layers. The electronic device according to the present embodiment is an example in which the thickness of the core, not the width of the core of the optical waveguide, may be different between adjacent optical waveguides.

  The electronic device according to the present embodiment is different from the electronic device according to the first or second embodiment in the cross-sectional structure of the optical wiring. Other points are the same as those of the electronic device according to the first or second embodiment. Therefore, only the structure of the optical wiring will be described, and other description will be omitted.

  FIG. 9 is a diagram illustrating the configuration of the optical wiring 56 provided in the electronic device according to the present embodiment.

  FIG. 9A is a plan view of the optical wiring 56. FIG. 9B is a cross-sectional view of the cross section taken along the line AA ′ of FIG.

  As shown in FIG. 9B, in the optical wiring 56, the second optical waveguide layer 68 is laminated on the first optical waveguide layer 66.

  The first optical waveguide layer 66 includes a first optical waveguide 62 having a core width of 3 μm and a thickness of 2 μm, and a second optical waveguide 64 having a core width of 2 μm and a thickness of 2 μm alternately. Arranged and configured. Here, the distance between the optical waveguide 62 and the optical waveguide 64 is 20 μm.

  The second optical waveguide layer 68 includes a third optical waveguide 58 having a core width of 3 μm and a thickness of 3 μm, and a fourth optical waveguide 60 having a core width of 2 μm and a thickness of 3 μm alternately. Arranged and configured. Here, the distance between the optical waveguide 58 and the optical waveguide 60 is 20 μm.

  The distance between the first optical waveguides 62 and 64 constituting the first optical waveguide layer 66 and the first optical waveguides 58 and 60 constituting the second optical waveguide layer 68 is also 20 μm.

  That is, in the same optical waveguide layer, optical waveguides having different core widths, such as the first optical waveguide 62 and the second optical waveguide 64, are adjacent to each other. On the other hand, between the different optical waveguide layers 66 and 68, optical waveguides having different core thicknesses, such as the first optical waveguide 62 and the third optical waveguide 58, are adjacent to each other.

  Therefore, in the optical wiring 56 in the present embodiment, either the width or thickness of the cross section of the core is different between adjacent optical waveguides.

  Therefore, in the electronic device according to the present embodiment, the signal light hardly transfers between the optical waveguides. Further, since the optical waveguides are laminated, optical wiring with higher density than the electronic devices of the first to third embodiments is possible.

  In the example of FIG. 9, either the width or the thickness of the core cross section of the optical waveguides 58, 60, 62, 64 is different. However, the laminated structure of the optical waveguide layers is not limited to such a configuration. For example, as shown in FIG. 10, optical waveguide layers 66 and 68 that are different from each other and adjacent to each other (optical waveguide 60 and optical waveguide 62, Both the thickness and width of the cores of the optical waveguide 58 and the optical waveguide 64) may be different.

  Further, the planar structure of the laminated optical waveguide layers 66 and 68 is not limited to the structure in which stripe-shaped optical waveguides having different widths are alternately arranged as shown in FIG. 9A. For example, FIG. The optical waveguides 46 and 48 in which the short optical waveguides 50 and 52 having different widths are connected in cascade as shown in FIG. 6 are opposed to the short optical waveguides (the short optical waveguide 50 and the short optical waveguide 52) having different widths. The structure may be arranged as described above.

  The present embodiment relates to a method of manufacturing an optical wiring constituting the electronic device according to the first to fourth embodiments.

  11 to 13 are cross-sectional process diagrams illustrating a method for manufacturing the optical wirings 22, 24, and 44 according to the first to third embodiments. The optical wiring 56 according to the fourth embodiment is different from the following manufacturing process in that the optical waveguide layer is formed and laminated twice, but is common in other points.

  First, for example, a polyimide resin solution for clad formation (Hitachi Kasei, trade name: OPI-N3205) is applied on a flat substrate 8 made of any one of quartz, glass, silicon, ceramic, and resin by spin coating. And cured by heating at 350 ° C. The cured polyimide resin solution forms a lower clad 70 made of polyimide (FIG. 11A).

  Next, a polyimide resin solution for core formation (Hitachi Chemical Co., Ltd., trade name: OPI-N3305 or OPI-N3405) is applied onto the lower clad 70 by spin coating, and is cured by heating at 350 ° C. The cured polyimide resin solution forms a core resin layer 72 made of polyimide (FIG. 11B).

  Next, a metal thin film 74 is deposited on the core resin layer 72 by sputtering or vapor deposition (FIG. 11C).

  Next, a photoresist film is applied on the metal thin film 74 to form a resist pattern 76 corresponding to the core shape of the optical wiring to be formed (FIG. 12D).

  Next, using the resist pattern 76 as a mask, the metal thin film 74 is wet etched to form a metal thin film pattern 78 (FIG. 12E).

  Next, using the metal thin film pattern 78 as a mask, the core resin 72 is dry-etched to form a core (FIG. 12F).

  Next, the metal thin film pattern 78 is removed, and a polyimide resin solution for clad formation (Hitachi Chemical Co., Ltd., trade name: OPI-N3205) is applied again by spin coating, and cured by heating at 350 ° C. The cured polyimide resin solution forms an upper clad 82 made of polyimide (FIG. 13).

  Through the above steps, an optical wiring having a predetermined core shape is formed on the substrate 8 with the clads 70 and 82 made of polyimide and the core 80.

  In the above example, the width and thickness of the core of the optical waveguide constituting the optical wiring are 2 μm or 3 μm. Therefore, these optical waveguides are single mode optical waveguides. However, the optical waveguide constituting the optical wiring is not necessarily a single mode optical waveguide, and may be a multimode optical waveguide.

  In the above example, the light-emitting element 14 that converts the electrical signal transmitted by the semiconductor device 2 into an optical signal and the light-receiving element 16 that converts the optical signal into an electrical signal and supplies the electrical signal to the semiconductor device 2 are each a surface-type light emission. It was an element (surface emitting laser) and a surface light receiver.

  However, the light emitting element 14 or the light receiving element 16 is not limited to a surface type optical element, and may be a waveguide type optical element. For example, the light emitting element 14 may be a Fabry-Perot laser, for example. The light receiving element 16 may be a waveguide type photodiode. In this case, the light emitting element 14 and the light receiving element 16 can be optically coupled directly to the optical waveguide constituting the optical wiring without using the 45 ° mirror 18.

  Furthermore, in the above-described example, the optical wiring according to the present invention is used for optical signal transmission (signal transmission by light) between semiconductor devices (in-board optical wiring). However, the application range of the optical wiring according to the present invention is not limited to the optical signal transmission between the semiconductor devices, but the signal transmission between the electronic devices composed of a plurality of semiconductor devices (inter-board optical wiring) or in the semiconductor device. It is also applicable to signal transmission (in-chip optical wiring).

  The present invention can be used in an electronic device manufacturing industry or a semiconductor device manufacturing industry comprising a plurality of semiconductor devices.

FIG. 3 is a diagram (part 1) for explaining the principle of the first embodiment; FIG. 2 is a diagram (part 2) for explaining the principle of the first embodiment; FIG. 4 is a third diagram illustrating the principle of the first embodiment; 1 is a plan view illustrating a configuration of an electronic device in Example 1. FIG. 1 is a cross-sectional view illustrating a configuration of an electronic device in Example 1. FIG. It is a figure explaining the structure of the optical wiring in Embodiment 1 and Example 1. FIG. 6 is a plan view illustrating a configuration of an electronic device according to Embodiment 2 and Example 2. FIG. It is a figure explaining the structure of the optical wiring which concerns on this Embodiment 3 and Example 3. FIG. It is a figure explaining the structure of the optical wiring which concerns on Example 4 (the 1). It is a figure explaining the structure of the optical wiring which concerns on Example 4 (the 2). It is sectional drawing explaining the manufacturing method of the optical wiring concerning Example 5 (the 1). It is sectional drawing explaining the manufacturing method of the optical wiring concerning Example 5 (the 2). It is sectional drawing explaining the manufacturing method of the optical wiring concerning Example 5 (the 3). It is a top view explaining the electronic device provided with the optical wiring which transmits the signal exchanged between semiconductor devices with light (related art). It is sectional drawing explaining the electronic device provided with the optical wiring (related technique). It is a figure explaining the structure of the optical wiring which comprises an electronic device (related technique).

Explanation of symbols

2 ... Semiconductor device 4 ... Optical wiring 6 ... Electronic device (related technology)
DESCRIPTION OF SYMBOLS 8 ... Substrate 10 ... Optical signal 12 ... Optical waveguide 14 ... Light emitting element 16 ... Light receiving element 18 ... 45 degree mirror
20 ... Substrate with electrical wiring 22 ... Electronic device (Embodiment 1)
DESCRIPTION OF SYMBOLS 21 ... Support 24 ... Optical wiring (Embodiment 1) 26 ... 1st optical waveguide (Embodiment 1)
28: Second optical waveguide (Embodiment 1)
30, 32... Optical waveguides 34 arranged close to each other in parallel... Electronic device (Embodiment 2) 36... First semiconductor device 38.
40... Optical signal transmitted from the first semiconductor device to the second semiconductor device 42... Optical signal transmitted from the second semiconductor device to the first semiconductor device 44. Form 3) 46, 48 ... Optical waveguide (Embodiment 3)
50, 52 ... Short optical waveguide 54 ... Transition region 56 ... Optical wiring (Example 4)
58, 60, 62, 64 ... Optical waveguide (Example 4)
66 ... First waveguide layer 68 ... Second waveguide layer 70 ... Lower cladding 72 ... Core resin layer 74 ... Metal thin film 76 ... Resist pattern 78 ... Metal thin film pattern 80 ... Core 82 ... Upper clad
84, 86 ... Optical waveguides adjacent in the center

Claims (2)

A substrate,
A plurality of semiconductor devices formed on the substrate for processing electrical signals;
An optical wiring composed of a plurality of optical waveguides formed on the substrate, which transmits an optical signal obtained by converting a signal exchanged between the semiconductor devices from electricity to light,
In the electronic device in which the optical wiring includes a region in which the optical waveguides are formed in parallel to each other,
In the area,
A cross section of the core of the optical waveguide is formed in a rectangular shape,
The first and second optical waveguides composed of the adjacent optical waveguides are:
A plurality of short optical waveguides in which the refractive indexes of the core and the clad are equal, and either one or both of the width and thickness of the cross section are different are connected in cascade.
Said first and said second optical waveguide each constructed and adjacent short optical waveguide, cross-talk between the first and second optical waveguide so that less -30 dB, the pre-Symbol section One or both of the width and the thickness are different from each other. The electronic device according to claim 1 ,
A value obtained by summing up the lengths of the short optical waveguides is the same between the first and second optical waveguides for each of the short optical waveguides having different one or both of the width and thickness of the cross section. An electronic device characterized by that.

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