JP2011227371A - Semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor package which comprises: a semiconductor element chip; multiple photoelectric conversion modules; external light connecting parts, the number of which is smaller than that of the multiple photoelectric conversion modules; and multiple optical waveguides formed between the multiple photoelectric conversion modules and the external light connecting parts, the semiconductor package being able to decrease an absolute value of optical losses at the multiple optical waveguides, reduce the variation of optical losses at the multiple optical waveguides, and make the multiple optical waveguides be disposed in a small area.SOLUTION: Multiple optical waveguides 5 are bundled and connected to external light connecting parts, the number of which is smaller than that of the multiple photoelectric conversion modules 3, and each optical waveguide 5 comprises, viewed from the side of the external light connecting parts: a first straight line part 14; a curved line part 15 having no inflection points; and a second straight line part 16 whose linear direction is different from the linear direction of the first straight line part 14.

Description

  The present invention relates to a semiconductor package with an optical interface including at least one semiconductor element chip and a plurality of photoelectric conversion modules capable of mutual conversion between an electric signal and an optical signal.

  Along with the spread of the Internet, the amount of information handled by communication devices such as servers and routers has increased rapidly, and exchanged between multiple semiconductor elements such as LSI (large-scale integrated circuit) mounted on these communication devices. It is predicted that the transmission capacity of the transmitted signals will increase further. From such a background, high speed and large capacity of signal transmission between a plurality of semiconductor elements such as LSIs are important issues.

Conventionally, a plurality of semiconductor elements such as LSIs are connected to each other by electrical wiring to transmit an electrical signal. However, electrical signal transmission has the following problems.
First, in electrical wiring, the higher the signal transmission rate, the more the signal waveform deteriorates due to loss, reflection, crosstalk, etc., and the probability of transmission errors increases. By using a waveform shaping circuit or the like, a deteriorated signal waveform can be repaired to some extent. However, as the signal transmission rate increases, the waveform shaping circuit becomes more complicated and larger in scale, and the power consumption increases.
Secondly, in order to reduce crosstalk between electrical wirings, it is necessary to devise measures such as widening the wiring interval or providing a shield between the wirings, so that it is difficult to mount the wirings at a high density, and the entire device is downsized. Is difficult.
Third, since electrical wiring is affected by electromagnetic noise, a shield or the like is necessary to reduce the influence of electromagnetic noise, and it is difficult to mount wiring at high density, and it is difficult to reduce the size of the entire device.

Since electric wiring has the above-described problems, there is an increasing expectation for “optical interconnection technology” in which a plurality of semiconductor elements such as LSIs are connected by optical wiring to transmit an optical signal. Optical wiring has the following advantages over electrical wiring.
First, in optical wiring, the influence of high-frequency loss and reflection is so small that it can be ignored and there is no crosstalk, so signal degradation is very small. Therefore, a waveform shaping circuit is not required and power consumption is small.
Second, since optical wiring has no crosstalk, it is not necessary to devise measures such as increasing the wiring interval or providing a shield between the wirings, enabling high-density mounting of the wiring, and reducing the size of the entire device. It is.
Third, since optical wiring is not affected by electromagnetic noise, shielding against electromagnetic noise or the like is unnecessary, high-density mounting of wiring is possible, and the entire device can be downsized.
Since optical wiring has the above advantages, high-speed and large-capacity signal transmission between multiple semiconductor elements such as LSI can be realized with high density and low power by using optical interconnection technology. It is expected to be possible.

In optical interconnection, an optical interface that performs mutual conversion between electrical signals and optical signals is required.
The optical interface is generally composed of an optical element composed of a light emitting element such as a laser diode or a light receiving element such as a photodiode, and an electric circuit electrically connected thereto. Non-Patent Document 1 proposes a semiconductor package with a built-in optical interface in which an LSI chip and an optical interface are mounted on the same substrate. The optical interface is usually a module of a photoelectric conversion module in which an optical element chip including at least one optical element composed of a light emitting element or a light receiving element and an electric element chip including an electric circuit are mounted on a substrate. It is mounted with. By mounting a plurality of photoelectric conversion modules having different types of optical elements or mounting at least one photoelectric conversion module having a plurality of different types of optical elements, a semiconductor package capable of optical input / output can be realized. If a plurality of photoelectric conversion modules are mounted on one semiconductor package, it is possible to transmit signals through a plurality of channels, which is preferable.

Considering the simplicity of external wiring, a single or a plurality of external optical wirings connectable to one connector are connected to a semiconductor package with a built-in optical interface of a plurality of channels, and a plurality of external optical wirings are connected via the external optical wiring. It is preferable that an optical signal is output from the photoelectric conversion module and an optical signal is input to the plurality of photoelectric conversion modules.
In the present specification, the “external optical wiring” includes a cable in which a plurality of single core optical fiber wirings are bundled. As the external optical wiring, one or a plurality of multi-core optical fiber wirings can also be used.

A polymer optical waveguide having a laminated structure of a lower cladding layer, a core layer, and an upper cladding layer is preferable as the plurality of internal optical wirings connecting the plurality of photoelectric conversion modules and the external optical wiring.
When a plurality of optical fibers are used as the plurality of internal optical wirings, it takes time and labor to install a plurality of channels of optical fibers and to process these extra lengths. In addition, since the external optical wirings must be connected to the individual photoelectric conversion modules using different optical connectors, the same number of optical connectors and external optical wiring units as the photoelectric conversion modules are required.
On the other hand, in the case of an optical waveguide, multiple channels of optical wiring of an arbitrary shape can be collectively formed by polymer coating film formation, lithography technology, etc., and the assembly cost of a semiconductor package can be reduced compared to the case of using an optical fiber. . It is possible to bundle a plurality of optical waveguides and connect them to external optical wiring via one optical connector.
By optically connecting multiple photoelectric conversion modules and external optical wiring using multiple optical waveguides, the assembly cost of the semiconductor package can be reduced, the number of expensive optical connectors can be reduced, and the external wiring structure can be simplified. .

In order to reduce the size of a semiconductor package with a built-in optical interface, it is an important issue to bend a plurality of optical waveguides with a radius of curvature as small as possible and aggregate them in a narrow range with high density.
As a collective pattern of the plurality of optical waveguides when the plurality of optical waveguides are bundled and connected to the external optical wiring, a pattern indicated by reference numeral 5 in FIG.

  A configuration of a conventional semiconductor package with a built-in optical interface will be described with reference to the drawings. 16 is an overall top view of a board on which a conventional semiconductor package is mounted, and FIGS. 17 and 18 are partially enlarged views (perspective views) of FIG. These figures correspond to FIGS. 1 to 3 of a semiconductor package according to an embodiment of the present invention which will be described later. The cross-sectional structure is the same as that of the semiconductor package of one embodiment according to the present invention to be described later, so please refer to that.

In the conventional semiconductor package 1000, one LSI chip (semiconductor element chip) 102 is provided on the upper surface of the package substrate 101, and four photoelectric conversion modules 103 connected to the LSI chip 102 via electrical wiring 104. And are installed.
On the package substrate 101, a mirror 110 (see FIG. 17) is provided below each photoelectric conversion module 103, and a polymer optical waveguide 105 is formed so as to be connected thereto. A plurality of optical waveguides 105 provided corresponding to the plurality of photoelectric conversion modules 103 are bundled and connected to the external optical fiber wiring 107 via one optical connector 106.
The semiconductor package 1000 and the external optical fiber wiring 107 are mounted on the board 111, and electrical signals are exchanged between the board 111 and the package 1000 via the electrical wiring 112, power feeding, GND (ground) connection, and the like. It is like that.

  As shown in an enlarged view in FIG. 18, each photoelectric conversion module 103 is obtained by mounting one optical element chip 132 and one electric element chip 133 including an electric circuit on a substrate 131. In this example, four optical elements 134 are mounted on one optical element chip 132 in a straight line.

The aggregate pattern of the plurality of optical waveguides 105 in the semiconductor package 1000 is shown by reference numeral 5 in FIG.
That is, as shown in an enlarged view in FIG. 17, each optical waveguide 105 has a first straight portion 114 parallel to the center line 113 of the package 1000 and an inflection point when viewed from the external optical fiber wiring 107 side. It has a curved pattern having a curved portion 115 and a second straight portion 116 parallel to the center line 113 of the package. The curved portion 115 having an inflection point is formed between the first straight portion 114 and the inflection point, the first curved portion 115A convexly curved toward the center line 113 of the package, the inflection point and the first inflection point. The second curved portion 115B is formed between the two straight portions 116 and is concavely curved toward the center line 113 of the package. In this pattern, the distance from the center line 113 of the package increases the length of the curved portion 115 of the optical waveguide 105 and the entire length of the optical waveguide 105.

  As shown in an enlarged view in FIG. 18, in each photoelectric conversion module 103, the optical element chip 132 and the electric element chip 133 are both substantially rectangular, and these are the sides of the optical element chip 132 and the electric element. Each side of the chip 133 is arranged in parallel to each other. In the optical element chip 132, the plurality of optical elements 134 are arranged in a direction substantially orthogonal to the second straight portion 116 of the optical waveguide 105.

JP 2000-294809 JP Japanese Patent No.4214862

Hiyama et al. "High-speed optical interconnection using system LSI module with built-in optical I / O" Proceedings of Society Conference of IEICE 2004.

  In the optical waveguide pattern shown in FIG. 17, the length of the curved portion 115 of the optical waveguide 105 and the entire length of the optical waveguide 105 increase as the distance from the center line 113 of the package increases. Therefore, the optical waveguide 105 has a large variation in optical loss, and the output power of the photoelectric conversion module must be adjusted for each channel.

  In general, in an optical waveguide, the optical loss in a curved portion is larger than the optical loss in a straight portion. Further, the optical loss tends to increase as the radius of curvature of the curved portion decreases. In particular, these tendencies are remarkable in a polymer optical waveguide that can be directly formed on a package substrate.

  In the actual measurement example of the epoxy polymer optical waveguide by the inventor, the loss of the linear waveguide was 0.06 dB / cm, but the loss of the arc-shaped curved waveguide having a radius of curvature of 5 mm and an inner angle of 90 ° was 0. It was 53 dB / cm. Since the length of this arc is 0.79 cm, the optical loss is about 9 times that of a straight waveguide having the same length.

  In the pattern shown in FIG. 17, the present inventor has drawn the curved portion 105 of the optical waveguide 105 with a radius of curvature of 5 mm and the size of the photoelectric conversion module 103 as 4 mm square. In this example, the length of the curved portion 115 is 4 between the longest polymer optical waveguide (the waveguide farthest from the package centerline 113) and the shortest polymer optical waveguide (the waveguide closest to the package centerline 113). .9mm is also different.

  Based on the optical loss data obtained from the actual measurement by the inventor, the loss of the straight line portion is set to 0.06 dB / cm, and the loss of the arc-shaped curved portion having a curvature radius of 5 mm is calculated to be 0.53 dB / cm. As a result, the optical loss of the longest polymer optical waveguide was 0.62 dB, the optical loss of the shortest polymer optical waveguide was 0.38 dB, and the difference between the optical losses of the longest and shortest polymer optical waveguides was 0.24 dB. This difference is a level that cannot be ignored.

  In general, at the optical connector 106 that is the output end of the semiconductor package 1000 with a built-in optical interface, it is necessary to make the powers of the optical signals of all channels substantially the same. In order to do so, the output power of each photoelectric conversion module must be adjusted so that the output power of the photoelectric conversion module gradually increases as the distance from the center line 113 of the package increases.

  In the pattern of FIG. 17, the photoelectric conversion module 103 farthest from the center line 113 of the package must output 0.24 dB larger power than the photoelectric conversion module 103 closest to the center line 113 of the package. In terms of percentage, the photoelectric conversion module 103 farthest from the package center line 113 must output about 5% larger power than the photoelectric conversion module 103 closest to the package center line 113.

If the curvature radius of the curved portion 115 of the polymer optical waveguide 105 is increased, the optical loss in the curved portion 115 can be reduced and the loss difference between channels can be reduced. In this case, the size of the semiconductor package 1000 is increased, and the package Cannot be downsized.
Even if the radius of curvature of the curved portion 115 of the curved portion 105 is doubled to 10 mm, the loss of the curved optical waveguide is still 3.7 times the loss of the straight waveguide, so that the variation in loss between channels is different. Is not resolved.

As an aggregate pattern of a plurality of optical waveguides, a pattern shown in FIG. 1 of Patent Document 2 has been proposed.
The pattern of the optical waveguide described in Patent Document 2 is shown in FIG. In this pattern, a plurality of straight portions 122, 125, 128 parallel to the package center line 113, a plurality of curved portions 123, 126 convexly curved toward the package center line 113, and the package center line 113 are directed. And a plurality of curved portions 124 and 127 that are concavely curved. In this pattern, the lengths of the straight portions of all the optical waveguides 105 can be made equal, and the radius of curvature and the length of the curved portions can be made equal, so that the optical loss difference between channels can be eliminated.

  However, in the pattern shown in FIG. 19, the length and overall length of the curved portion of the optical waveguide are longer than the curved portion of the pattern shown in FIG. 17, and the absolute value of the optical loss is increased. In this case, the output power of the photoelectric conversion module 103 must be increased, and the power consumption of the photoelectric conversion module 103 increases. Further, since the entire length of the optical waveguide is longer than the pattern shown in FIG. 17, the size of the semiconductor package 1000 is increased, and the package cannot be reduced in size.

The present invention has been made in view of the above circumstances, and includes at least one semiconductor element chip, a plurality of photoelectric conversion modules, a smaller number of external optical connection portions than the plurality of photoelectric conversion modules, and a plurality of photoelectric conversion modules. And a plurality of optical waveguides formed between the external optical connection portion,
A semiconductor package that can reduce the absolute value of optical loss in a plurality of optical waveguides, can reduce variations in optical loss between the plurality of optical waveguides, can be arranged in a small area, and can reduce the overall size of the package Is intended to provide.

The semiconductor package of the present invention is
On the mounting board,
At least one semiconductor element chip;
An optical element chip including at least one optical element composed of a light emitting element or a light receiving element and an electric element chip including an electric circuit connected to the optical element are mounted and electrically connected to the electric element chip. And a plurality of photoelectric conversion modules optically connected to the external optical wiring,
An external optical connection to which the external optical wiring is connected;
A semiconductor package comprising a plurality of optical waveguides formed between the plurality of photoelectric conversion modules and the external optical connection portion,
A plurality of the optical waveguides are bundled and connected to a smaller number of the external optical connection portions than the photoelectric conversion module,
Each of the optical waveguides includes a first linear portion, a curved portion having no inflection point, and a second linear direction different from that of the first linear portion as viewed from the external optical connection portion side. It consists of a straight part.

  According to the present invention, the absolute value of optical loss in a plurality of optical waveguides can be reduced, variation in optical loss between the plurality of optical waveguides can be reduced, the plurality of optical waveguides can be arranged in a small area, and the entire package can be reduced in size. It is possible to provide a semiconductor package with a built-in optical interface.

1 is an overall top view of a board on which a semiconductor package with a built-in optical interface according to an embodiment of the present invention is mounted. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG. It is whole sectional drawing of FIG. It is the elements on larger scale of FIG. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is a figure which shows the example of a design change. It is the whole board top view carrying the conventional semiconductor package with a built-in optical interface. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG. It is a figure which shows another prior art.

"Semiconductor package with built-in optical interface"
With reference to the drawings, a configuration of a semiconductor package with a built-in optical interface according to an embodiment of the present invention will be described. The semiconductor package 100 of this embodiment can be used for optical interconnection of electronic devices such as servers, routers, and computers.
FIG. 1 is an overall top view of a board on which the semiconductor package of this embodiment is mounted, and FIGS. 2 and 3 are partially enlarged views (perspective views) of FIG. 4 is a cross-sectional view taken along the line AB of FIG. 1, and FIG. 5 is a partially enlarged view of FIG. In order to facilitate visual recognition, the scale of each component is appropriately different from the actual one.

  As shown in FIGS. 1 and 4, in the semiconductor package 100 of the present embodiment, one large-scale integrated circuit (LSI) chip (semiconductor element chip) 2 is formed on the upper surface of a package substrate (mounting substrate) 1. A plurality of photoelectric conversion modules 3 connected to the LSI chip 2 via electrical wiring 4 are mounted using solder balls 8.

As shown in FIG. 5, in each photoelectric conversion module 3, one optical element chip 32 and one electric element chip 33 including an electric circuit are flip-chip mounted on a substrate 31 using solder balls 35. It is a thing. The optical element chip 32 and the electric element chip 33 are electrically connected via an electric wiring 36. As shown in FIG. 3, in this embodiment, a plurality of optical elements 34 are mounted on a single optical element chip 32 in a straight line.
The mounting method of the optical element chip 32 and the electric element chip 33 in the photoelectric conversion module 3 is not limited to the above-described mode, and may be mounting using wire bonding, TAB, or the like.
The number of optical element chips 32 and electric element chips 33 mounted on each photoelectric conversion module 3 can be designed as appropriate, and the number of optical element chips 32 and / or electric element chips 33 may be plural.

  Each optical element 34 mounted on the optical element chip 32 is a light emitting element such as a laser diode or a light receiving element such as a photodiode. An electric circuit for driving the light emitting element is mounted on the electric element chip 33 mounted on the photoelectric conversion module 3 including the light emitting element as the optical element 34. An electric circuit for amplifying an electric signal from the light receiving element is mounted on the electric element chip 33 mounted on the photoelectric conversion module 3 including the light receiving element as the optical element 34.

  The electric element chip 33 is subjected to an arbitrary process other than an electric circuit for driving the light emitting element 34 of the optical element chip 32 or an electric circuit for amplifying the electric signal output from the light receiving element 34 of the optical element chip 32. A circuit may be included. The optical element chip 32 may be formed not only with the optical element 34 but also with any electronic device or electric circuit, for example, a drive circuit for driving the optical element 34.

  The photoelectric conversion module 3 including the light emitting element and the electric circuit that drives the light emitting module is an optical transmission module that transmits an optical signal. The photoelectric conversion module 3 including the light receiving element and the electric circuit that amplifies the electric signal from the light receiving element is optical. It becomes an optical receiving module that receives a signal.

In the photoelectric conversion module 3 (optical transmission module) including a light emitting element and an electric circuit for driving the light emitting element, when an electric signal is input to the photoelectric conversion module 3, the electric circuit of the electric element chip 33 is converted to the optical element chip 32. The light emitting element is driven to emit light, and an optical signal is output from the photoelectric conversion module 3.
In the photoelectric conversion module 3 (light receiving module) including a light receiving element and an electric circuit for amplifying an electric signal from the light receiving element, when the optical signal is input to the photoelectric conversion module 3, the light receiving element of the optical element chip 32 Converts the optical signal into an electric signal, the electric signal of the electric element chip 33 is amplified by the electric signal, and the electric signal is output from the photoelectric conversion module 3.

On the package substrate 1, a mirror 10 is formed below each optical element chip 32, and a plurality of optical waveguides 5 are formed in connection with the mirror 10. Each optical waveguide 5 is provided corresponding to each optical element 34.
In the present embodiment, the mirror 10 is a slope formed on the substrate 31 by dicing or laser processing. A reflective film may be formed on this slope by metal vapor deposition or the like.
In this embodiment, the optical waveguide 5 is a polymer optical waveguide formed in a lump by polymer coating film formation, lithography technology, or the like. The optical waveguide 5 has a laminated structure of a lower cladding layer 5A, a core layer 5B, and an upper cladding layer 5C.
As the material of the optical waveguide 5, a polymer having a refractive index larger than that of the base of the optical waveguide 5 is used.
Examples of the combination of the materials of the substrate 1 / optical waveguide 5 include a polymer such as a silicon substrate having a surface silicon oxide film / a fluorinated polyimide having a higher refractive index than SiO ₂ .
The mirror 10 is formed obliquely so as to face the end faces of the optical element 34 and the optical waveguide 5 on the optical element 34 side.

In the present embodiment, one LSI chip 2 and four photoelectric conversion modules 3 are mounted on the package substrate 1, and four optical elements 34 are mounted on the optical element chips 32 of the individual photoelectric conversion modules 3. Sixteen optical waveguides 5 are formed, and 16-channel signal transmission is possible.
In the semiconductor package 100, two of the four photoelectric conversion modules 3 are optical transmission modules, and the remaining two are optical reception modules, and are configured to allow optical input / output.
However, the present invention is not limited to the above embodiment, and the type and number of semiconductor element chips 2, the number of photoelectric conversion modules 3, the number of optical elements 34 mounted on each optical element chip, and the number of optical waveguides 5 are appropriately designed. It can be changed.

The semiconductor package 100 is provided with one optical connector (external optical connection portion) 6 to which one external optical fiber wiring (external optical wiring) 7 is connected. The plurality of optical waveguides 5 are bundled and connected to one optical connector 6.
In the present embodiment, the external optical fiber wiring 7 is an optical fiber cable formed by bundling a plurality of single core optical fiber wirings. As the external optical fiber wiring 7, one multi-core optical fiber wiring or an optical fiber cable formed by bundling a plurality of multi-core optical fiber wirings can also be used.
The semiconductor package 100 and the external optical fiber wiring 7 are disposed on the board 11. Electrical wiring 12 is formed on the upper surface of the board 11, and the semiconductor package 100 is electrically connected to the electrical wiring 12 of the board 11 through the socket 9. Via the socket 9 and the electrical wiring 12, exchange of electrical signals between the board 11 and the package 100, power feeding, GND (ground) connection, and the like are performed.
The package substrate 1 and the on-board electrical wiring 12 are not limited to the connection mode using the socket 9 and may be connected using a solder ball or the like.

In the semiconductor package 100, the electrical signal output from the LSI chip 2 is input to the photoelectric conversion module 3 via the electrical wiring 4 of the package substrate 1 and converted into an optical signal. The optical signal output from the photoelectric conversion module 3 is converted in the optical path by the mirror 10, enters the optical waveguide 5, propagates in the optical waveguide 5, and is output to the external optical fiber wiring 7.
The optical signal input from the external optical fiber wiring 7 propagates in the optical waveguide 5, undergoes optical path conversion by the mirror 10, is input to the photoelectric conversion module 3, and is converted into an electrical signal. The electrical signal output from the photoelectric conversion module 3 is input to the LSI chip 2 via the electrical wiring 4 of the package substrate 1.
By using a plurality of semiconductor packages 100, high-speed and large-capacity optical signal exchange can be realized via the external optical fiber wiring 7.

  In this embodiment, as shown in an enlarged view in FIG. 2, the 16 (4 × 4) channel optical waveguides 5 are arranged in line symmetry with respect to the center line 13 of the package. When viewed from the optical connector 6 side (external optical fiber wiring 7 side), a first straight portion 14 parallel to the package center line 13 and a curve having no inflection point that is convex toward the package center line 13 It is comprised from the part 15, the 1st linear part 14, and the 2nd linear part 16 from which a line direction differs.

In the present embodiment, the radius of curvature and the length of the curved portion 15 of the optical waveguide 5 of all 16 channels are designed to be substantially equal. Further, in the present embodiment, the inclination angles of the second straight portions 16 of the optical waveguides 5 of all 16 channels with respect to the first straight portion 14 (the package center line 13) are all substantially equal.
In this specification, “substantially equal” is defined as variation within 10% of a standard value (average value).

  In the conventional example shown in FIG. 17, the second straight portion of the optical waveguide is parallel to the center line of the package. However, in this embodiment, the second straight portion 16 of the optical waveguide 5 is in relation to the center line of the package. And slanted.

As shown in an enlarged view in FIG. 3, in the present embodiment, the optical element chip 32 and the electric element chip 33 mounted on each photoelectric conversion module 3 are both substantially rectangular chips.
In this specification, the “substantially rectangular shape” includes a square shape, a rectangular shape, a shape in which corners of these shapes are chamfered, and the like.
In this embodiment, the optical element chip 32 has a plurality of optical elements 34 mounted on a single straight line substantially parallel to one side 32S of the optical element chip 32.

In the present embodiment, the optical element chip 32, the electric element chip 33, and the optical waveguide 5 are such that the sides of the optical element chip 32 and the sides of the electric element chip 33 are not parallel to each other, and the light in the optical element chip 32 The arrangement direction of the element 34 and the second straight part 16 of the optical waveguide 5 are arranged in a non-parallel positional relationship.
In the present embodiment, the angle formed between the side 32S of the optical element chip 32 and the side 33S of the electrical element chip 33 facing each other is approximately 45 °, and the arrangement direction of the optical element 34 in the optical element chip 32 and the optical waveguide 5 The second straight portion 16 is substantially orthogonal.
In this specification, “substantially parallel” or “substantially orthogonal” is defined as a deviation angle of 0.8 ° or less from completely parallel or completely orthogonal.

In general, there is a standard for the pitch of the optical element in the optical element chip, and a pitch of 250 μm is common in a commercially available optical element chip. In the present embodiment, the optical elements 34 of the optical element chip 32 are arranged at a general 250 μm pitch.
In the present embodiment, four photoelectric conversion modules 3 are mounted on the package substrate 1. Four optical waveguides 5 extend from the individual photoelectric conversion modules 3 corresponding to the number of optical elements 34. The pitch of the four optical waveguides 5 extending from one photoelectric conversion module 3 is set to 250 μm, which is the same as the pitch of the optical element 34, and this pitch does not change from the photoelectric conversion module 3 side to the optical connector 6.
In the present embodiment, the pitch of the four photoelectric conversion modules 3 is set to 250 μm.
However, the pitch of the optical element 34, the pitch of the optical waveguide 5, and the pitch of the photoelectric conversion module 3 in the optical element chip 32 are not limited to the above, and are appropriately designed. The pitch on the optical connector 6 side of the optical waveguide 5 may not be set to be the same as the pitch of the optical elements 34. The pitch on the optical connector 6 side of the optical waveguide 5 may be narrower or wider than the pitch of the optical elements 34.

In the present embodiment, each optical waveguide 5 is viewed from the optical connector 6 side (external optical fiber wiring 7 side), the first straight portion 14, the curved portion 15 having no inflection point, and the first Since the straight portion 14 and the second straight portion 16 having different linear directions are used, the number of curved portions can be reduced as compared with the conventional examples shown in FIGS. Can be significantly shortened.
In FIG. 2, similarly to the conventional example of FIG. 17, the radius of curvature of the curved portion 15 of the optical waveguide 5 is 5 mm, and the size of the photoelectric conversion module 3 is 4 mm square. In this case, the length of the curved portion 15 of the longest optical waveguide 5 in the semiconductor package 100 of this embodiment is significantly reduced to 0.35 times the curved portion of the conventional example of FIG.

  In general, an optical waveguide has a large optical loss at a curved portion. Therefore, in this embodiment, the absolute value of the optical loss of the optical waveguide 5 can be reduced as compared with a conventional optical waveguide pattern having many curved portions. As an example, when a calculation comparison is made with a polymer optical waveguide made of the same material as that of the conventional example of FIG. 17, the optical loss of the longest polymer optical waveguide is 0.62 dB in the conventional example of FIG. In the configuration according to, the optical loss of the longest polymer optical waveguide is 0.26 dB. Therefore, according to the present invention, the optical loss of the longest optical waveguide 5 is reduced by 0.36 dB compared to the conventional example. Converted as a percentage, an optical loss of 0.36 dB corresponds to 8% of the signal. In this embodiment, since the absolute value of the optical loss in the optical waveguide 5 can be reduced, the output power of the photoelectric conversion module 3 can be reduced, and the power consumption of the photoelectric conversion module 3 can be reduced.

In general, since an optical loss greatly occurs in a curved portion, when viewing each optical waveguide 5 from the optical connector 6 side, a first straight portion 14, a curved portion 15 having no inflection point, and a first straight portion. 14 and the second straight line portion 16 having different linear directions, the number of curved portions is smaller than that of the conventional example, and the difference in optical loss between the 16-channel optical waveguides 5 can be reduced.
In this embodiment, the radius of curvature and the length of the curved portion 15 of the optical waveguide 5 of all 16 channels are designed to be substantially equal, but the radius of curvature and the length of the curved portion 15 of the optical waveguide 5 of all 16 channels are designed. Even if none of them is made substantially equal, the above-described effect that the difference in optical loss between the plurality of optical waveguides 5 can be reduced can be obtained.

In general, the optical loss greatly occurs in the curved portion, so even if there is a difference in the lengths of the straight portions of the plurality of optical waveguides 5, the difference in the optical loss is not significantly affected. If the curvature radii and lengths of the curved portions 15 of the optical waveguides 5 of all 16 channels are designed to be substantially equal, the optical loss difference between the optical waveguides 5 of all 16 channels can be made substantially zero.
As an example, when a calculation comparison is made with a polymer optical waveguide of the same material as the conventional example of FIG. 17, in the configuration of the present embodiment, the length of the straight portion is about 1.8 mm in the longest optical waveguide and the shortest optical waveguide. There is a difference. However, since the loss of the linear portion of the optical waveguide is as very small as 0.06 dB / cm, even if there is a difference of 1.8 mm in the length of the linear portion, the optical loss difference is 0.01 dB, which can be ignored in practical use. It is. In the configuration of the present embodiment, since the radius of curvature and the length of the curved portion of the longest optical waveguide and the shortest optical waveguide are both substantially equal, the optical loss of the curved portion of the longest optical waveguide and the shortest optical waveguide is the same. There is no difference. Therefore, in this embodiment, the optical loss of the longest optical waveguide is 0.26 dB, the optical loss of the shortest optical waveguide is 0.25 dB, and the optical loss difference between the longest and shortest optical waveguide is 0.01 dB. This is a practically negligible level. As a result, the output power of all the photoelectric conversion modules 3 may be set to be substantially the same, and adjustment of the output power of the photoelectric conversion module for each channel as in the conventional example becomes unnecessary.

The above calculation is merely an example, and the optical loss value naturally varies depending on the design specifications, the material of the optical waveguide 5, and the like.
In this embodiment, in the plurality of optical waveguides 5, attention is paid to the fact that the optical loss of the curved portion is dominant, and the difference in the loss of the straight portion is practically negligible for the difference in length on the order of mm. And the pattern is designed.

In the present embodiment, the curvature radii and lengths of the curved portions 15 of the optical waveguides 5 of all 16 channels are both designed to be substantially equal, and the first linear portions of the second linear portions 16 of the optical waveguides 5 of all 16 channels are designed. Since the inclination angles with respect to 14 (package center line 13) are designed to be substantially equal, the layout design of the multi-channel optical waveguide 5 is simple, and the time required for the design can be shortened. Even if the number of channels of the optical waveguide 5 is increased, it is sufficient to design with the same specifications, and it is possible to easily cope with the increase in number of channels.
In the present embodiment, since the number of curved portions is small, the overall length of the optical waveguide 5 can be made shorter than that of the conventional example. Therefore, the plurality of optical waveguides 5 can be disposed with a small area, and the entire package 100 can be downsized.

  As described above, according to the present embodiment, the absolute value of the optical loss in the plurality of optical waveguides 5 can be reduced, the variation in the optical loss between the plurality of optical waveguides 5 can be reduced, and the plurality of optical waveguides 5 can be reduced. It is possible to provide a semiconductor package 100 with a built-in optical interface that can be arranged in an area and can be downsized.

(Design changes)
In each photoelectric conversion module 3, the design of the arrangement pattern of the optical elements 34 in the optical element chip 32 and the positional relationship between the optical element chip 32, the electric element chip 33, and the second linear portion of the optical waveguide 5 can be appropriately changed. is there.

Examples of design changes are shown in FIGS. 6 to 9 correspond to FIG. 3 of the above embodiment.
In the design change example shown in FIG.
The optical element chip 32 and the electric element chip 33 are both substantially rectangular chips.
The optical element chip 32 has a plurality of optical elements 34 mounted on a single straight line that is not parallel to the side of the optical element chip 32.
The optical element chip 32, the electric element chip 33, and the optical waveguide 5 are such that the side of the optical element chip 32 and the side of the electric element chip 33 are substantially parallel to each other, and the side of the optical element chip 32 and the optical waveguide 5 The second linear portions 16 are arranged in a positional relationship that is not parallel to each other.
In this example, the side 32 </ b> S of the optical element chip 32 and the side 33 </ b> S of the electrical element chip 33 that face each other are substantially parallel, and the optical element chip 32 includes four optical elements 34 on the diagonal line of the optical element chip 32. Is arranged, and the arrangement direction (diagonal direction) of the optical element 34 in the optical element chip 32 and the second linear portion 16 of the optical waveguide 5 are substantially orthogonal to each other.

In the design change example shown in FIG. 7 and FIG.
The optical element chip 32 and the electric element chip 33 are both substantially rectangular chips.
The optical element chip 32 includes a plurality of optical elements 34 mounted on a plurality of straight lines substantially parallel to the sides of the optical element chip 32.
The optical element chip 32, the electric element chip 33, and the optical waveguide 5 are such that the side of the optical element chip 32 and the side of the electric element chip 33 are substantially parallel to each other, and the side of the optical element chip 32 and the optical waveguide 5 The second linear portions 16 are arranged in a positional relationship that is not parallel to each other.
In these examples, the side 32S of the optical element chip 32 and the side 33S of the electric element chip 33 facing each other are substantially parallel, and in the optical element chip 32, two substantially parallel to the side 32S of the optical element chip 32 are provided. Two optical elements 34 are mounted on the straight line.

In the design change example shown in FIG.
The optical element chip 32 and the electric element chip 33 are both substantially rectangular chips.
The optical element chip 32 has a plurality of optical elements 34 mounted on a single straight line substantially parallel to the side of the optical element chip 32.
The optical element chip 32, the electric element chip 33, and the optical waveguide 5 are such that the side of the optical element chip 32 and the side of the electric element chip 33 are substantially parallel to each other, and the side of the optical element chip 32 and the optical waveguide 5 The second linear portions 16 are arranged in a positional relationship that is not parallel to each other.
In this example, the side 32S of the optical element chip 32 and the side 33S of the electric element chip 33 facing each other are substantially parallel,
In the optical element chip 32, four optical elements 34 are mounted on one straight line substantially parallel to the side 32 </ b> S of the optical element chip 32.

  Even in the design change shown in FIGS. 6 to 9, the same effect as the above embodiment can be obtained. In the design changes shown in FIGS. 6 to 9, the optical element chip 32 does not have to be mounted obliquely with respect to the electric element chip 33, so that the mounting can be made easier than in the above embodiment.

(Other design changes)
In the above embodiment, the case where the optical element chip 32 and the electric element chip 33 are mounted side by side on the substrate 31 in the photoelectric conversion module 3 has been described.
As shown in FIG. 10, in the photoelectric conversion module 3, the optical element chip 32 and the electric element chip 33 are three-dimensionally stacked in the height direction, so that the photoelectric conversion module 3 is downsized and the semiconductor package 100 is downsized. Can be

In the example shown in FIG. 10, the optical element chip 32 is mounted on the lower surface of the substrate 31, and the electric element chip 33 is mounted on the upper surface of the substrate 31. FIG. 10 is a diagram corresponding to FIG. 5 of the above embodiment.
The embodiment of FIG. 10 in which the optical element chip 32 and the electric element chip 33 are three-dimensionally stacked in the height direction is applicable to any of the patterns in FIGS. 3 and 6 to 9.
FIG. 11 to FIG. 15 show an application of the embodiment of FIG. 10 in which the optical element chip 32 and the electric element chip 33 are three-dimensionally stacked in the height direction applied to the patterns of FIGS. 3 and 6 to 9.

(Other design changes)
The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope not departing from the gist of the present invention.
In the above embodiment, only one light emitting element or only a light receiving element is formed as one optical element chip 32 in one optical element chip 32. However, one light element chip 32 includes a light emitting element and a light receiving element. Both of them may be formed.
In the above embodiment, the photoelectric conversion module 3 and the optical waveguide 5 are optically coupled using only the mirror 10. However, for the purpose of improving the coupling efficiency, the photoelectric conversion module 3 and the optical waveguide 5 are combined with a lens, a connector, or the like. These optical members may be used or a combination of these and a mirror may be used for optical coupling. The material of the optical waveguide 5 may be other than a polymer.
In the above embodiment, the optical waveguide 5 is formed on the upper surface of the package substrate 1, but the optical waveguide 5 may be formed inside the package substrate 1.
In the above embodiment, the number of the optical connectors 6 and the external optical fiber wirings 7 is one, but the present invention can be applied if the number is smaller than that of the photoelectric conversion module 3.

100 Semiconductor package with built-in optical interface 1 Package substrate (mounting substrate)
2 LSI chip (semiconductor element chip)
3 Photoelectric conversion module 5 Optical waveguide 6 Optical connector (external optical connection part)
7 External optical fiber wiring (external optical wiring)
14 First linear portion 15 of optical waveguide 15 Curved portion 16 of optical waveguide Second linear portion 32 of optical waveguide Optical element chip 32S Optical element chip side 33 Electrical element chip 33S Electrical element chip side 34 Optical element

Claims (7)

On the mounting board,
At least one semiconductor element chip;
An optical element chip including at least one optical element composed of a light emitting element or a light receiving element and an electric element chip including an electric circuit connected to the optical element are mounted and electrically connected to the semiconductor element chip. And a plurality of photoelectric conversion modules optically connected to the external optical wiring,
An external optical connection to which the external optical wiring is connected;
A semiconductor package comprising a plurality of optical waveguides formed between the plurality of photoelectric conversion modules and the external optical connection portion,
A plurality of the optical waveguides are bundled and connected to a smaller number of the external optical connection portions than the photoelectric conversion module,
Each of the optical waveguides includes a first linear portion, a curved portion having no inflection point, and a second linear direction different from that of the first linear portion as viewed from the external optical connection portion side. A semiconductor package consisting of a straight section.   The semiconductor package according to claim 1, wherein the curvature radius and the length of the curved portion of the plurality of optical waveguides are substantially equal.   3. The semiconductor package according to claim 1, wherein the inclination angles of the second linear portions of the plurality of optical waveguides with respect to the first linear portion are substantially equal. Both the optical element chip and the electrical element chip are substantially rectangular chips,
The optical element chip has a plurality of optical elements mounted on at least one straight line substantially parallel to one side of the optical element chip.
The optical element chip, the electric element chip, and the optical waveguide are such that a side of the optical element chip and a side of the electric element chip are not parallel to each other, and the arrangement direction of the optical element in the optical element chip The semiconductor package according to claim 1, wherein the second linear portion of the optical waveguide is disposed in a positional relationship that is not parallel to each other. Both the optical element chip and the electrical element chip are substantially rectangular chips,
The optical element chip has a plurality of optical elements mounted on at least one straight line that is non-parallel to the side of the optical element chip.
The optical element chip, the electrical element chip, and the optical waveguide are such that the side of the optical element chip and the side of the electrical element chip are substantially parallel to each other, and the side of the optical element chip and the side of the optical waveguide The semiconductor package according to any one of claims 1 to 3, wherein the second linear portion is disposed in a positional relationship that is not parallel to each other. Both the optical element chip and the electrical element chip are substantially rectangular chips,
The optical element chip has a plurality of optical elements mounted on at least one straight line substantially parallel to the side of the optical element chip.
The optical element chip, the electrical element chip, and the optical waveguide are such that the side of the optical element chip and the side of the electrical element chip are substantially parallel to each other, and the side of the optical element chip and the side of the optical waveguide The semiconductor package according to any one of claims 1 to 3, wherein the second linear portion is disposed in a positional relationship that is not parallel to each other.   The semiconductor package according to claim 1, wherein the photoelectric conversion module is a module in which the optical element chip and the electric element chip are three-dimensionally mounted so as to overlap in a height direction.

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