JP2008198892A - Optical coupling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical coupling apparatus which can be miniaturized while securing reliability. <P>SOLUTION: The optical coupling apparatus includes: a first substrate provided with a recessed part on a first main surface; a first wiring pattern, a second wiring pattern, a third wiring pattern and a fourth wiring pattern provided on the first main surface of the first substrate; a second substrate bonded to the first main surface; a first light emitting element provided in an internal space formed by bonding the first main surface and the second substrate and electrically connected with the first and second wiring patterns, for emitting the light of a wavelength to be light-shielded by the first and second substrates; and a light receiving element provided in the internal space and electrically connected with the third and fourth wiring patterns, for receiving the light emitted from the first light emitting element. At least a part of the light emitted from the first light emitting element is reflected by the second substrate and is made incident on the light receiving element. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical coupling device.

  The optical coupling device includes a light emitting element and a light receiving element in a light shielding package, and converts an optical signal from the light emitting element driven by an electric input signal into an electric output signal again by the light receiving element. For this reason, signal transmission is possible in an electrically insulated state, and it is widely used in electronic devices including switching power supplies, FA controllers, and the like. In recent years, as the demand for higher functionality and miniaturization of electronic devices has increased, it has become increasingly necessary to reduce the size of optical coupling devices.

  In this optical coupling device, for example, a light-emitting element and a light-receiving element are mounted on a lead frame, a light-transmitting resin formed between the light-emitting element and the light-receiving element, and a light-shielding resin formed so as to be wrapped outside the light-transmitting resin It is set as the structure containing these.

However, there is a limit to downsizing while securing characteristics and reliability in a resin molding structure of a lead frame on which a light emitting element and a light receiving element are mounted.
There is a technology disclosure example regarding a photocoupler that can be reduced in size by preventing cracks due to springback of the lead frame (Patent Document 1).
JP 2001-358361 A

  The present invention provides an optical coupling device that can be reduced in size while ensuring reliability.

  According to one aspect of the present invention, a first substrate having a recess on a first main surface, a first wiring pattern provided on the first main surface of the first substrate, The second wiring pattern, the third wiring pattern, the fourth wiring pattern, the second substrate bonded to the first main surface, and the first main surface and the second substrate are bonded. A first light-emitting element that emits light having a wavelength that is provided in an internal space formed and is electrically connected to the first and second wiring patterns and is shielded by the first and second substrates; A light receiving element provided in the internal space, electrically connected to the third and fourth wiring patterns and receiving the light emitted from the first light emitting element, and the first light emitting element At least a part of the light emitted from the second substrate is reflected by the second substrate to receive the light Optical coupling apparatus is provided, characterized in that entering the child.

  According to another aspect of the present invention, a first substrate having a recess provided on a first main surface, and a first substrate provided on the first main surface of the first substrate. A wiring pattern, a second wiring pattern, a third wiring pattern, and a fourth wiring pattern; a second substrate bonded to the first main surface; the first main surface; A first light-emitting element which is provided in an internal space formed by bonding with a substrate and emits light having a wavelength shielded by the first and second substrates; and the first light-emitting element in the internal space A light receiving element that receives the light emitted from the first light emitting element, and a fifth wiring that is provided on the surface of the second substrate and is connected to the third wiring pattern And a sixth pattern provided on the surface of the second substrate and connected to the fourth wiring pattern. A wiring pattern, wherein one of the first light emitting element and the light receiving element is mounted on the first substrate, connected to the first and second wiring patterns, and the first light emitting element. One of the element and the light receiving element is mounted on the second substrate, and is connected to the fifth and sixth wiring patterns. An optical coupling device is provided.

  According to another aspect of the present invention, a first substrate having a recess provided on a first main surface, and a first substrate provided on the first main surface of the first substrate. A wiring pattern, a second wiring pattern, a third wiring pattern, a fourth wiring pattern, and a light-receiving element made of a semi-insulating semiconductor and formed on the surface, and bonded to the first main surface Mounted on the first substrate so as to face the light receiving element in an internal space formed by joining the second substrate, the first main surface, and the second substrate. And a first light emitting element that emits light having a wavelength that is electrically connected to the second wiring pattern and is shielded by the first and second substrates, and the light receiving device provided on the surface of the second substrate. A fifth wiring pattern for connecting an element and the third wiring pattern; and Optical coupling device characterized by comprising: the sixth wiring pattern for connecting the light receiving element provided on a surface and the fourth wiring patterns, is provided.

  The present invention provides an optical coupling device that can be reduced in size while ensuring reliability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A and 1B show an optical coupling device according to a first embodiment of the present invention, in which FIG. 1A is a schematic perspective view, FIG. 1B is a schematic cross-sectional view along the line AA, and FIG. c) is a schematic perspective view of the inside. The first substrate 10 including a semi-insulating semiconductor has a recess 12, and a light emitting element 30 and a light receiving element 32 are mounted on the bottom surface inside the recess 12. Wiring patterns 42, 44, 46, 48 for connecting the electrodes of the light emitting element 30 and the light receiving element 32 with bonding wires 34, 35, 36 are provided from the inner surface of the recess 12 provided in the first main surface 40. 1 to the main surface 40.

  One electrode of the light emitting element 30 is connected to the wiring pattern 46, and the other electrode is connected to the wiring pattern 48. In FIG. 1, the light emitting element 30 is mounted on a wiring pattern 46, and one electrode (not shown) is connected to the wiring pattern 46 from the back surface of the chip of the light emitting element 30. The other electrode (not shown) is connected to the wiring pattern 48 by wire bonding 36. The electrodes (not shown) of the light receiving element 32 are connected to the wiring patterns 44 and 42 by bonding wires 34 and 35, respectively.

  Further, the second substrate 60 bonded to the first main surface 40 of the first substrate 10 has a light reflecting surface 62 in a region facing the recess 12 of the first substrate 10. That is, this embodiment is a reflective optical coupling device. The light reflecting surface 62 can be formed of metal, dielectric, resin, and the like, and the shape thereof is not limited to the concave curved surface, and may be a convex curved surface or a flat surface.

  The light emitting element 30 emits light by an input electric signal applied to the light emitting element 30 via the wiring patterns 46 and 48, and the reflected light from the light reflecting surface 62 enters the light receiving element 32. The signal converted by the light receiving element 32 becomes an output electric signal and is taken out through the wiring patterns 42 and 44. For this reason, the input side and the output side can transmit signals while maintaining electrical insulation.

  The material of the first substrate 10 is, for example, a semi-insulating semiconductor, for example, Si. The light emitting element 30 is an infrared light emitting element using, for example, GaAlAs or GaAs material. The light receiving element 32 is, for example, a photodiode or phototransistor using Si. The substrate is Si, and malfunction of the light receiving element 32 due to external light is suppressed.

The material of the second substrate 60 having the light reflecting surface 62 and bonded to the first substrate 10 is a semi-insulating semiconductor or a resin molded body. When semiconductors are used for the first and second substrates 10 and 60, the materials may be the same or different. The second substrate 60 also has a light shielding property so as to suppress malfunction of the light receiving element 32 due to external light. That is, the first and second plates 10 and 60 are made of an insulating material or a semi-insulating material having a light shielding property.
Note that the internal space formed by bonding the first substrate 10 and the second substrate 60 is desirably a vacuum or a reduced pressure in order to prevent an increase in internal pressure due to heating.

  In the first embodiment, if the material of the first substrate 10 is a semiconductor, a semiconductor microfabrication process can be used to form the recess 12 and the wiring patterns 42, 44, 46, 48. FIG. 2 is a process cross-sectional view illustrating a manufacturing process of the optical coupling device according to the present embodiment. First, as shown in FIG. 2A, the recess 12 and the non-through opening 14 are formed on the first main surface 40 of the first substrate 10 by the RIE method or the like.

  Subsequently, as shown in FIG. 2B, wiring patterns 42 and 44 are formed by a lithography method along the first main surface 40, the inner surface of the recess 12, and the non-through opening 14. The wiring patterns 42 and 44 are metal layers or ion implantation layers. In this case, an ion implantation layer can be used in addition to the chip mounting region and the wire bonding region.

  Subsequently, as shown in FIG. 2C, the vicinity of the non-penetrating opening 14 is removed from the second main surface 41 side which is the back surface of the first substrate 10 by the RIE method or the like to provide the back surface opening 16, and the wiring pattern 42, 44 is exposed. Subsequently, as shown in FIG. 2D, external wiring patterns 52 and 54 are formed in the vicinity of the back surface opening 16 and connected to the wiring patterns 42 and 44, respectively. Further, the light emitting element 30 and the light receiving element 32 are bonded in the recess 12 and connected by wire bonding or the like.

  Subsequently, as shown in FIG. 2E, the second and first substrates 60 and 10 are bonded with, for example, an adhesive so that the light reflecting surface 62 faces the recess 12. Further, the chip is separated by a dicing method or the like to obtain the structure of FIG. In this way, the electrodes of the light emitting element 30 and the light receiving element 32 are connected to the external wiring pattern through the non-through opening 14 and the back surface opening 16.

  In the first embodiment shown in FIG. 1, a recess 12 is formed in a first substrate 10 including a semiconductor by a microfabrication process, and is formed between a light reflecting surface 62 provided on a second substrate 60. By making optical coupling in the inner space, the package can be made smaller than a lead frame and a resin package. In this case, since the strength of the package is maintained by the substrate, it is not necessary to make the lead frame thick and thick.

Further, since the terminals of the optical coupling device are not leads but external wiring patterns provided on the first substrate 10, the width can be reduced, the thickness can be reduced, and lead bending is not required. For this reason, downsizing is further facilitated than the lead frame structure, and a CSP (Chip Scale Package) structure is also possible. The wiring pattern formed on the first main surface 40 may be only provided on the second main surface 41 of the first substrate 10 without providing the external wiring pattern. It is preferable to form the pattern on the second main surface 41 side of the first substrate 10. FIG. 3 shows a modification of the manufacturing process, and the first and second substrates 10 and 60 are bonded together under vacuum or reduced pressure. It is process sectional drawing in the case of doing. First, as shown in FIG. 3A, the recess 12 and the non-through opening 14 are formed on the first main surface 40 of the first substrate 10 by the RIE method or the like.

  Subsequently, as shown in FIG. 3B, wiring patterns 42 and 44 are formed by a lithography method along the first main surface 40, the inner surface of the recess 12, and the non-through opening 14. The wiring patterns 42 and 44 are metal layers or ion implantation layers. In this case, the region other than the chip mounting region and the wire bonding region can be an ion implantation layer. The light emitting element 30 and the light receiving element 32 are mounted with silver paste or AuSn solder, and connected to the wiring pattern by wire bonding or the like.

  The first main surface 40 of the first substrate 10 is bonded to a second substrate 60 having a light reflecting surface 62 containing metal, dielectric, resin, etc. under vacuum or reduced pressure. If the second substrate 60 is also a semiconductor, the process is performed by wafer bonding. In this case, the semiconductor materials do not have to be the same, but it is preferable to have a light shielding property against the emitted light from the light emitting element 30. In the structure in which the semiconductor wafers are bonded together, the substrate can be bonded more reliably and easily.

  Subsequently, as shown in FIG. 3C, the vicinity of the non-through opening 14 is removed from the second main surface 41 side which is the back surface of the first substrate 10 by the RIE method or the like to expose the wiring patterns 42 and 44. Further, as shown in FIG. 3D, external wiring patterns 52 and 54 are formed from the second main surface 41 side and connected to the wiring patterns 42 and 44, respectively.

  Subsequently, the chip is separated by dicing or the like to obtain the structure of FIG. In this way, the electrodes of the light emitting element 30 and the light receiving element 32 are connected to the external wiring pattern through the non-penetrating opening 14 and the back surface opening 16, respectively.

  In FIG. 1, when the light receiving element 32 is made of Si, the mounting process including the mounting can be simplified by making the light receiving element 32 on the substrate, and the miniaturization can be facilitated because the wire bonding region is not necessary. If two light emitting elements 30 are connected in reverse parallel between the wiring patterns 46 and 48, an AC input optical coupling device can be obtained.

  FIG. 4 is a schematic perspective view of the optical coupling device according to the second embodiment of the present invention. In the present embodiment, the transparent resin 20 (represented by dots) is provided so as to cover the light emitting element 30 and the light receiving element 32 in the recess 12, and the light emitting element 30 and the light receiving element 32 are protected. An opening 18 that is spaced from the corner of the recess 12 is formed in the first main surface 40 via the groove 19. In this way, when bonded to the second substrate 60, a part of the opening 18 and the groove 19 becomes a non-formation region of the transparent resin 20, and the expanded transparent resin 20 enters the opening 18 and the groove 19. It is more preferable because it can escape along.

That is, the linear expansion coefficient of the transparent resin is about 3 × 10 ⁻⁴ / ° C., which is about one digit larger than that of Si, the lead frame, and the mold resin. For this reason, adhesiveness is insufficient between the substrate and the transparent resin, and between the mold resin and the transparent resin, and the transparent resin may be peeled off due to a difference in expansion and contraction due to a temperature change. This peeling changes the light coupling efficiency. Further, cracks may occur in the mold resin due to the expansion of the transparent resin.

On the other hand, in this embodiment, even if the transparent resin 20 expands and contracts, an internal space (a part or the whole of the groove portion 19 and the opening portion 18) that serves as a escape place for the transparent resin 20 is provided. Peeling of the resin 20 and cracking of the mold resin can be suppressed. Therefore, fluctuations in optical coupling efficiency can be suppressed, and characteristics and reliability can be easily ensured.
Note that the groove 19 and the opening 18 may be provided on the second substrate 60, or may be provided on both the first substrate 10 and the second substrate 60.

  In addition, the first substrate 10 is a semi-insulating semiconductor, and the second substrate 60 is a semi-insulating substrate or resin, both of which are light-shielding. 1 and 4, the reflection type optical coupling device in which the light emitting element 30 and the light receiving element 32 are arranged in the recess 12 provided in the first substrate 10 has been described. However, the present invention is not limited to this, and may be a counter-type optical coupling device in which one is disposed on the second substrate 60.

  5A and 5B show a counter-type optical coupling device according to a third embodiment of the present invention. FIG. 5A is a schematic perspective view of a second substrate, FIG. 5B is a schematic cross-sectional view, and FIG. (C) is a schematic perspective view of a 1st board | substrate. In the present embodiment, the light emitting element 30 is mounted on the first substrate 10, and the light receiving element 32 is mounted on the second substrate 60. In this case, the first and second substrates 10 and 60 are bonded together to form an internal space including two concave portions. The wiring patterns 66 and 68 of the second substrate 60 are connected to the wiring patterns 42 and 44 of the first substrate 10 respectively, and all external wiring patterns are provided on the second main surface 41 of the first substrate 10. . In the present embodiment, it is easy to increase the distance between the light emitting element 30 and the light receiving element 32 and improve the withstand voltage. In contrast to the one shown in FIG. 5, the light emitting element 30 may be mounted on the second substrate 60 and the light receiving element 32 may be cloaked on the first substrate 10.

  Further, instead of mounting the chip-shaped light receiving element 32 on the second substrate 60, the light receiving element 32 can be formed on the second substrate 60. That is, the light receiving element 32 can be formed by performing diffusion or patterning on the surface of the second substrate 60 made of Si. If it does in this way, a mounting process can be simplified and size reduction will become easier. Further, in the optical output device of logic output or MOSFET output, the integrated circuit 69 in which the light receiving element 32 and other elements are incorporated, and when this is built in the second substrate 60, is an opposed type and stable and high. An optical coupling device that can be miniaturized while having coupling efficiency becomes possible. That is, also in this case, the integrated circuit 69 can be formed by performing a process such as diffusion or patterning on the surface of the second substrate 60 made of Si.

  Further, for example, two or more light-emitting elements that are electrically independent can be arranged, and a signal can be output from one light-receiving element 32. 6A and 6B show an optical coupling device according to a fourth embodiment of the present invention. FIG. 6A is a schematic perspective view of a second substrate, FIG. 6B is a schematic cross-sectional view, and FIG. FIG. 3 is a schematic perspective view of a first substrate. In the present embodiment, two light emitting elements 30 and 31 are mounted on the first substrate 10, and independent wiring patterns 46, 47, 48 and 49 are respectively provided. By arranging a plurality of pairs of such light emitting elements 30, 31 and light receiving elements 32, a small multi-channel optical coupling device can be realized.

On the other hand, the light receiving element 32 may be disposed on the first substrate 10, and the two light emitting elements 30 and 31 may be mounted on the second substrate 60. In this case, four wiring patterns connected to the light emitting elements 30 and 31 are provided on the second substrate 60. The first substrate 10 is provided with two wiring patterns connected to the light receiving element 32 and four wiring patterns respectively connected to the four wiring patterns provided on the second substrate 60.
That is, the seventh and eighth wiring patterns provided on the first main surface, the ninth wiring pattern provided on the surface of the second substrate and connected to the seventh wiring pattern, A tenth wiring pattern provided on a surface of the second substrate and connected to the eighth wiring pattern; provided in the internal space; and electrically connected to the ninth and tenth. And a second light emitting element that emits light having a wavelength that is shielded by the second substrate, wherein the light receiving element receives the light emitted from the second light emitting element, and 3. The optical coupling device according to claim 2, wherein the second light emitting element is mounted on the second substrate, and the light receiving element is disposed on the first substrate.

  As described above, in the first to fourth embodiments, a transparent resin that covers the light emitting element and the light receiving element in the internal space is further provided, and at least one of the first and second substrates has a structure having a groove portion that communicates with the internal space. can do.

  Furthermore, in the first to fourth embodiments, the wiring patterns of the light emitting elements 30, 31 and the light receiving element 32 are non-parallel and easy to make vertical, and reduce the floating capacitance between input and output. be able to. In the conventional structure, since the input / output leads are parallel and the lead area is large, the floating capacitance is large. For example, even if an attempt is made to shorten the switching time at turn-on and turn-off by a MOSFET integrated with a light receiving element, there is a limit to shortening the switching time due to the floating capacitance. On the other hand, in this embodiment, it is easy to shorten the switching time.

  As described above, in the embodiment of the present invention, an optical coupling device that can transmit a signal in a state where the input and the output are insulated and can be easily downsized while ensuring reliability is provided. This optical coupling device can be used in a wide range of switching power supplies, FA controllers, medical electronic devices, and the like.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments. For example, even if a person skilled in the art has changed the design regarding the shape, material, size, arrangement, etc. of the light-emitting element, light-receiving element, integrated circuit, substrate, transparent resin, mold resin, etc. constituting the optical coupling device It is included in the scope of the present invention without departing from the gist of the invention.

The schematic diagram of the optical coupling device concerning 1st Embodiment. Process sectional drawing showing the manufacturing process of 1st Embodiment. Process sectional drawing showing the modification of the manufacturing process of 1st Embodiment. The schematic diagram of the optical coupling device concerning 2nd Embodiment. The schematic diagram of the optical coupling device concerning 3rd Embodiment. It is a schematic diagram of the optical coupling device concerning 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st board | substrate, 12 recessed part, 20 transparent resin, 30, 31 light emitting element, 32 light receiving element, 40 1st main surface, 42, 44, 46, 47, 48, 49 wiring pattern, 52, 58 external wiring pattern , 60 Second substrate, 62 Light reflecting surface, 66, 68 Wiring pattern

Claims (5)

A first substrate provided with a recess in the first main surface;
A first wiring pattern, a second wiring pattern, a third wiring pattern, and a fourth wiring pattern provided on the first main surface of the first substrate;
A second substrate bonded to the first main surface;
Provided in an internal space formed by bonding the first main surface and the second substrate, and electrically connected to the first and second wiring patterns, by the first and second substrates. A first light emitting element that emits light of a wavelength to be blocked;
A light receiving element that is provided in the internal space and that is electrically connected to the third and fourth wiring patterns and receives the light emitted from the first light emitting element;
With
At least a part of the light emitted from the first light emitting element is reflected by the second substrate and enters the light receiving element. A first substrate provided with a recess in the first main surface;
A first wiring pattern, a second wiring pattern, a third wiring pattern, and a fourth wiring pattern provided on the first main surface of the first substrate;
A second substrate bonded to the first main surface;
A first light-emitting element that is provided in an internal space formed by bonding the first main surface and the second substrate and that emits light having a wavelength that is blocked by the first and second substrates; ,
A light receiving element that is provided opposite to the first light emitting element in the internal space and receives the light emitted from the first light emitting element;
A fifth wiring pattern provided on the surface of the second substrate and connected to the third wiring pattern;
A sixth wiring pattern provided on the surface of the second substrate and connected to the fourth wiring pattern;
With
Either one of the first light emitting element and the light receiving element is mounted on the first substrate and connected to the first and second wiring patterns,
One of the first light emitting element and the light receiving element is mounted on the second substrate, and is connected to the fifth and sixth wiring patterns. A first substrate provided with a recess in the first main surface;
A first wiring pattern, a second wiring pattern, a third wiring pattern, and a fourth wiring pattern provided on the first main surface of the first substrate;
A second substrate made of a semi-insulating semiconductor, having a light receiving element formed on the surface, and joined to the first main surface;
The first main surface and the second substrate are mounted on the first substrate so as to face the light receiving element in an internal space formed by bonding, and the first and second wiring patterns are electrically connected to the first substrate. A first light-emitting element that emits light having a wavelength that is connected to each other and shielded by the first and second substrates;
A fifth wiring pattern provided on the surface of the second substrate and connecting the light receiving element and the third wiring pattern;
A sixth wiring pattern provided on the surface of the second substrate and connecting the light receiving element and the fourth wiring pattern;
An optical coupling device comprising: Seventh and eighth wiring patterns provided on the first main surface;
A second light emitting element that emits light having a wavelength that is provided in the internal space and is electrically connected to the seventh and eighth wiring patterns and shielded by the first and second substrates;
Further comprising
The optical coupling device according to claim 1, wherein the light receiving element receives the light emitted from the second light emitting element. Seventh and eighth wiring patterns provided on the first main surface;
A second light emitting element that emits light having a wavelength that is provided in the internal space and is electrically connected to the seventh and eighth wiring patterns and shielded by the first and second substrates;
Further comprising
The light receiving element receives the light emitted from the first and second light emitting elements;
The first and second light emitting elements are mounted on the first substrate;
4. The optical coupling device according to claim 2, wherein the light receiving element is disposed on the second substrate.

Images