KR100901446B1 - Package structure of optical connection module and its manufacturing method - Google Patents

Abstract

The present invention relates to a package structure of the optical connection module and a method of manufacturing the same. A driving IC, an electrode pattern suitable for the shape of the light emitting device, a through-hole array for transmitting an optical signal to the outside, and connecting an external power source. An LTCC base substrate having a power pad and a ground pad formed thereon, and a first space for mounting the driver IC and a second space for mounting the light emitting device, respectively, stacked on one surface of the LTCC base substrate and separately formed on the LTCC base substrate. A through-hole is formed to connect to the outside in the LTCC block having a plurality of contact pads at a predetermined position of the upper surface, the inside of the first space is sealed with a liquid polymer material that is cured by ultraviolet or heat Packaged as an element with an LTCC substrate, mass production is possible through surface mounting on the substrate It is good.

Fiber Optic Module, LTCC, Package, Via Hole, Contact Pad, Surface Mount, Mounting Space

Description

Package structure for optical connection module and manufacturing method thereof {Package structure for transmitting / receiving module and manufacturing method}

1 is a three-dimensional perspective view of an optical connection module package structure according to an embodiment of the present invention.

FIG. 2 is a plan view of the optical connection module package structure shown in FIG.

3A to 3E are schematic perspective views showing a manufacturing process of a package structure of an optical connection module according to an embodiment of the present invention.

4 is a bridge-type connection example using an optical fiber to an optical connection module according to an embodiment of the present invention.

         <Explanation of symbols for the main parts of the drawings>

10: LTCC base substrate 12: electrode pattern

14 ground pad 15 through hole

16: power pad 20: LTCC block

22: first space 23: via hole

24: second space 25: contact pad

30: driving chip 40: light emitting device or light receiving device

100: optical transmission module 200: optical reception module

300: optical fiber

The present invention relates to a package structure of an optical connection module and a method of manufacturing the same. More particularly, a low temperature co-fired ceramic (LTCC) substrate is applied to a module constituting an optical transmitter or an optical receiver that emits and receives an optical signal. The present invention relates to a package structure of an optical connection module and a method for manufacturing the same, which allow mass production through surface mounting on a substrate by packaging as one device.

In general, in low-speed electronic systems, the connection between circuit boards and circuit boards, chips and chips or systems is made through electrical metal wiring, but in next-generation information and communication systems consisting of large parallel computers or ATM switching systems of 1 Tb / s or more As the information is increased in volume and the transmission speed is improved, electrical problems such as skew, electromagnetic interference (EMI), etc. are generated when the metal wiring is used, and thus the operation efficiency of the system is reduced and system integration becomes difficult.

In recent years, with the development of mobile communication, it is expected that digital TV can be watched or recorded in future mobile phones and PDAs such as 3G and 4G, and the data demand is expected to increase.

In addition, in accordance with higher transmission requirements in the future, flexible PCBs for electric transmission using existing polyimides connecting the main board and the display will reach the limit of transmission.

On the other hand, recently, a technology for making an optical connection by using an optical transmission / reception module has been developed. In the optical coupling method inside the optical transmission / reception module, a ribbon optical fiber multichannel optical connector having a reflector positioned at an inclination angle of 45 ° is provided. Direct coupling of the optical transceiver to the polymer optical waveguide with a polymer optical waveguide having a reflector positioned at an inclination angle of 45 °, and connecting the polymer optical waveguide to the multichannel optical connector. And a method of vertically coupling an optical transmission / reception element fixed to a plastic package to a multi-channel optical connector.

The technique of vertically connecting light in the light source and coupling the light waveguide is known as an "optical module" or an "optical connection module".

However, although the optical module or the optical connection module is composed of an optical transmitter or optical receiver and includes a semiconductor device such as a driving IC and a light emitting element or a light receiving element, it is difficult to form on the same wafer in the manufacturing process.

Therefore, the devices are mounted on a substrate in the form of flip chips and are mainly connected through wire bonding.

However, the manufacturing process has a problem that it is very difficult to apply the surface mounting technology (SMT, which is applied to the current mass production.

The present invention provides a substrate by packaging a module constituting the optical transmitter or optical receiver that emits and receives an optical signal as one element applying a low temperature co-fired ceramic (LTCC) substrate in order to solve the conventional problems as described above. The present invention provides a package structure of an optical connection module and a method of manufacturing the same, which enable mass production through surface mounting.

Another object of the present invention is to provide a package structure of an optical connection module and a method of manufacturing the same, which easily connect a flat waveguide or an optical fiber in the form of a bridge by placing a light source unit of a light transmitting unit or a light receiving unit of a light receiving unit opposite to an electrode pad.

The package structure of the optical connection module according to the present invention for solving the above-mentioned conventional problems and to achieve the above object, the driving pattern, the electrode pattern to match the shape of the driving IC, the light emitting device at the position where the light emitting device is mounted And a through-hole array for transmitting the optical signal emitted from the light emitting device to the outside, a low temperature co-fired ceramic (LTCC) base substrate having a power pad and a ground pad for connecting an external power source, and the LTCC base substrate. The first space for mounting the driver IC and the second space for mounting the light emitting device are separately formed on one surface, and the electrode pattern, the power pad, or the ground pad for connecting to the outside from the LTCC base substrate. An LTCC block having a plurality of contact pads formed at predetermined positions on an upper surface thereof is formed by connecting vertical through holes. The driving IC is connected by wire bonding in contact with the electrode pattern of the LTCC base substrate in the first space of the LTCC block, and the light emitting device is mounted in contact with the electrode pattern in the second space. And the inside of the first space is sealed with a liquid polymer material which is cured by ultraviolet rays or heat.

In addition, the package structure of the optical connection module according to another embodiment of the present invention, the driving IC, the electrode pattern matching the shape of the driving IC, the light receiving element at the position where the light receiving element is mounted and the optical signal received by the light receiving element Through-hole array for receiving the light from the outside, a low temperature co-fired ceramic (LTCC) base substrate on which a power pad and a ground pad for connecting an external power source are formed, and stacked on one surface of the LTCC base substrate to mount the driving IC The first space and the second space for mounting the light receiving element are separately formed, and a vertically penetrated via hole connected to the electrode pattern, the power pad, or the ground pad for connecting to the outside from the LTCC base substrate is formed. An LTCC block having a plurality of contact pads at a predetermined position on an upper surface thereof, the LTCC block being disposed in the first space of the LTCC block; The driving IC is connected by wire bonding in contact with the electrode pattern of the LTCC base substrate, the liquid crystal device is mounted in contact with the electrode pattern in the second space, and the inside of the first space is cured by ultraviolet rays or heat. It is characterized by being sealed with a polymeric material of.

In addition, in the package structure of the optical connection module according to the present invention, a metal film is coated on the inner surface of the through hole of the through hole array.

 In addition, in the package structure of the optical connection module according to the present invention, the metal film coated on the inner surface of the through hole is characterized in that it is selected from Au, Ag, Cu, Al, Pt.

In addition, in the package structure of the optical connection module according to the present invention, the light emitting device is characterized in that it comprises a surface emitting laser (VCSEL) array.

In addition, in the package structure of the optical connection module according to the present invention, the light receiving element is characterized in that it comprises a photodiode array.

On the other hand, the manufacturing method of the package structure of the optical connection module according to the present invention comprises the steps of forming an electrode pattern, ground pad, power pad in accordance with the shape of the driving IC and the light emitting element on the LTCC base substrate, and the light emitting element of the LTCC base substrate Forming a through hole that is a passage for transmitting an optical signal to the outside in alignment with the mounting position, and mounting the first space and the light emitting device to mount the driving IC on one surface of the LTCC base substrate. Stacking an LTCC block having a second space for separation, and forming a via hole vertically penetrating a predetermined portion of the LTCC block corresponding to an electrode pattern, a power pad, and a ground pad of the LTCC base substrate; And forming a contact pad on an upper surface of the LTCC block in which the via hole is formed, and the LTCC bay inside the first space. Connecting a driving IC by wire bonding in contact with the electrode pattern of the substrate, and mounting a light emitting device in contact with the electrode pattern in the second space in the second space, and in the first space Filling the liquid polymer material and curing with ultraviolet or heat to seal.

In addition, the manufacturing method of the package structure of the optical connection module according to another embodiment of the present invention comprises the steps of forming an electrode pattern, ground pad, power pad to match the shape of the driving IC and the light receiving element on the LTCC base substrate, and the LTCC base Forming a through hole that is a passage for receiving an optical signal from the outside in alignment with the position where the light receiving element of the substrate is mounted; a first space for mounting the driving IC on one surface of the LTCC base substrate, and the light receiving Stacking an LTCC block having a second space for mounting the device, and forming a via hole penetrating perpendicularly to a predetermined portion of the LTCC block corresponding to an electrode pattern, a power pad, and a ground pad of the LTCC base substrate; Forming a contact pad on an upper surface of the LTCC block in which the via hole is formed; Connecting the driving IC by wire bonding in contact with the electrode pattern of the LTCC base substrate, and mounting a light receiving element in contact with the electrode pattern in the second space within the second space; and Filling the inside of the liquid polymer material in one space and curing by sealing with ultraviolet or heat.

In addition, the manufacturing method of the package structure of the optical connection module according to the present invention, characterized in that it further comprises the step of forming a metal reflective surface on the inner surface of the through-hole formed in the LTCC base substrate.

In the method of manufacturing a package structure of an optical connection module according to the present invention, in the step of forming a power pad on the LTCC base substrate, a capacitor is formed under the power pad as a passive element and embedded therein and connected to a ground pad. It is characterized in that it further comprises.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a three-dimensional perspective view of an optical connection module package structure according to an embodiment of the present invention, Figure 2 is a plan view of the optical connection module package structure shown in FIG.

1 and 2, an optical connection module package structure according to an embodiment of the present invention includes a low temperature co-fired ceramic (LTCC) base substrate 10, a first space 22 for mounting a driving IC, and the light emission. And an LTCC block 20 which separately forms the second spaces 24 for device mounting.

Here, the low temperature co-fired ceramic (LTCC) is to form a substrate using a simultaneous firing method of ceramic and metal at a low temperature of about 800 ~ 1000 ℃, glass and ceramics having a low melting point is mixed to have an appropriate dielectric constant A green sheet is formed, and a conductive paste of silver or copper is printed and laminated thereon to form a substrate, and then passive elements such as capacitors, resistors, and inductors are embedded in the substrate. High integration, light and small, high reliability can be achieved.

In addition, LTCC packages made of ceramic and silver have very good electrical and thermal properties, making them well suited for packaging components that operate beyond several GHz, such as optical interconnect modules.

In the LTCC base substrate 10, an electrode pattern 12 and the light emitting device that match the shape of the driving IC 30 and the light emitting device 40 are mounted at a position where the driving IC 30 and the light emitting device 40 are mounted. An array of through holes 15 for transmitting the optical signal emitted from the 40 to the outside, a power pad 16 and a ground pad 14 for connecting an external power source are formed.

In addition, the LTCC block 20 is stacked on one surface of the LTCC base substrate 10 and independently separates the first space 22 for mounting the driver IC and the second space 24 for mounting the light emitting device. Form.

1 and 2, at the peripheral edge of the LTCC block 20, the electrode pattern 12, the power pad 16, or the ground pad (not shown) for connecting from the LTCC base substrate to the outside. A vertical through hole (Via hole) 23 connected to 14 is formed.

The via hole is also exposed at a predetermined position on the upper surface of the LTCC block 20 to form a plurality of contact pad portions 25.

In this case, the contact pad part 25 formed on the upper surface of the LTCC block 20 through which the via hole 23 is exposed is for an external interface as in the case of making electrical contact with another external substrate.

1 and 2, the LTCC base substrate 10 for forming an electrode pattern suitable for the shape of the driving IC 30 and the light emitting element 40 is preferably as thin as 300 μm or less. It is to minimize the loss in the process of entering and exiting light through the through hole (15).

Here, it is also possible to form the RLC passive element inside the LTCC base substrate 10 by using the advantages of the LTCC process.

If the capacitor is formed under the power pad 16 as the built-in passive device and connected to the ground pad 14, power noise introduced from an external power source may be reduced.

 In the optical transmission module, a vertical cavity surface emitting laser (VCSEL) array is mounted as the light emitting device 40 mounted in the second space 24, and a metal half is provided in the through hole array 20 for transmitting an optical signal from the VCSEL array. A slope is formed.

Here, the metal to be plated on the inner wall of the through-hole array 15 formed in the LTCC base substrate 10 may be selected from Au, Ag, Cu, Al, Pt.

In addition, the driving IC 30 is connected to the electrode pattern 12 of the LTCC base substrate 10 in the first space 22 of the LTCC block 20 by wire bonding. The light emitting device 40 is mounted in the two spaces 24 in contact with the electrode pattern 12.

In this case, the inside of the first space 22 is wire bonded after the mounting of the driving IC, the wire bonding is very sensitive to external impact, so to increase the reliability of the device inside the first space 22 is ultraviolet ( UV) or heat filled with a liquid polymer material that is cured and sealed.

The first space 22 and the second space 24 are separated by a wall, which is formed when the inside of the first space 22 is filled with a polymer material before the liquid polymer material is cured. It flows into the second space 24 and flows into the through hole 15 at the bottom of the second space 24 by capillary action, thereby preventing contamination of the light passage.

Therefore, in order to package the driving IC 30 and the light emitting device 40, as shown in FIG. 1, the tubular structure is very efficient.

 When the polymer material filling the first space 22 is cured, the above device can be used without a special process of blocking the upper surface of the LTCC block 20.

At this time, the height of the LTCC block 20 should be higher than the height of the bonding wire when wire bonding after mounting the driving chip 30 in the first space (22).

The package structure shown in FIGS. 1 and 2 can be equally applied to an optical receiving module.

Accordingly, the LTCC base substrate 10 of the package structure of the optical connection module according to another embodiment of the present invention has an electrode pattern suitable for the shape of the driving IC and the light receiving element 40 at the position where the driving IC and the light receiving element are mounted. 12 and an array of through holes 15 for receiving the optical signal received by the light receiving element from the outside, a power pad 16 and a ground pad 14 for connecting an external power source are formed.

In addition, an LTCC block 20 is stacked on one surface of the LTCC base substrate 10 to separately form the first space 22 for mounting the driver IC and the second space 24 for mounting the light receiving element, respectively. A vertically penetrated via hole 23 connected to the electrode pattern 12, the power pad 16, or the ground pad 14 for connecting to the outside from the LTCC base substrate 10 is formed to provide a predetermined upper surface. A plurality of contact pad portions 25 are provided in position.

In this case, the driving IC 30 is connected by wire bonding in contact with the electrode pattern 12 of the LTCC base substrate 10 in the first space 22 of the LTCC block 20. The light receiving element 40 is mounted in contact with the electrode pattern 12 in the second space 24, and the first space 22 is sealed with a liquid polymer material that is cured by ultraviolet rays or heat.

Here, a photo diode array is used as the light receiving element 40 in the light receiving module.

The circuit pattern 12 formed on the LTCC substrate 10 is for transmitting an electrical signal to a connector for connection with an optical transmitter or a light receiver and a driving chip 30 for driving the light emitting device or the light receiving device 40. .

The reason for plating the inner surface of the through hole 15 with metal is that the optical signal emitted from the light emitting element or received from the light receiving element is totally reflected by the plated metal, thereby reducing the coupling loss between the optical waveguides of the light emitting element. This is because the coupling loss between the optical waveguide and the light receiving element can be reduced.

3A to 3E are schematic perspective views showing a manufacturing process of a package structure of an optical connection module according to an embodiment of the present invention.

First, in order to fabricate the package structure of the optical connection module, as shown in FIG. 3A, the electrode pattern 12, the ground pad 14, The power pad 16 is formed.

In this case, in the step of forming the power pad 16 on the LTCC base substrate 10, the method may further include a process of embedding a capacitor under the power pad 16 as a passive element and connecting the ground pad 14 to the ground pad 14. .

In addition, an array of through holes 15, which serve as a passage for transmitting optical signals to the outside, is formed through a mechanical drill or laser processing in alignment with the positions where the light emitting devices 40 of the LTCC base substrate 10 are mounted (FIG. 3a).

Next, a first space 22 for mounting the driver IC 30 and a second space 24 for mounting the light emitting device 40 are separately provided on one surface of the LTCC base substrate 10. The LTCC blocks 20 are stacked to form a tubular structure (FIG. 3B).

 Next, the via hole 23 vertically penetrates the wall surface of the LTCC block 20 corresponding to the electrode pattern 12, the power pad 16, and the ground pad 14 of the LTCC base substrate 10. Form (Fig. 3c).

Next, a contact pad 25 is formed on the upper surface of the LTCC block 20 in which the via hole 23 is formed (FIG. 3D).

Finally, the driving IC 30 is connected by wire bonding in contact with the electrode pattern 12 of the LTCC base substrate 10 in the first space 22, and inside the second space 24. The light emitting device 40 is mounted in contact with the electrode pattern 12 (FIG. 3E).

At this time, the first polymer 22 is filled with a liquid polymer material and cured with ultraviolet rays or heat to seal the inside of the first space 22.

In the manufacturing process of the package structure of the optical connection module, in the case of the optical receiving module, if the manufacturing method is applied to the receiving device instead of the light emitting device, the package structure of the optical receiving module is manufactured.

Figure 4 shows the optical connection module according to an embodiment of the present invention connected in the form of a bridge using an optical fiber.

In FIG. 4, the light transmitting module 100 and the light receiving module 200 are respectively connected to each other by the optical fiber 300 at positions opposite to the electrode pad 12.

In addition, in the package structure of the optical connection module, the contact pad 25 formed on the upper surface of the LTCC block 20 is faced down and the contact pad is in electrical contact with a terminal portion of another substrate.

As described above, according to the package structure of the optical connection module and the manufacturing method thereof according to the present invention, by mass-packing the surface of the substrate by packaging the module constituting the optical transmitter or the optical receiver as a device applying the LTCC substrate There is an advantage to being possible.

In addition, there is an effect that it is easy to connect the flat waveguide or the optical fiber in the form of a bridge by placing the light source portion of the light transmitting portion or the light receiving portion of the light receiving portion opposite to the electrode pad.

Although the invention has been described in detail only with respect to the specific embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and modifications belong to the appended claims. will be.

Claims (10)

A driving IC, an electrode pattern suitable for the shape of the driving IC, the light emitting device, a through-hole array for transmitting the optical signal emitted from the light emitting device to the outside, and a power pad for connecting an external power source A low temperature co-fired ceramic (LTCC) base substrate having a ground pad formed thereon; And The electrode pattern and the power pad, which are stacked on one surface of the LTCC base substrate and separately form the first space for mounting the driving IC and the second space for mounting the light emitting device, and are connected to the outside from the LTCC base substrate. Or a LTCC block having a plurality of vertically penetrated via holes connected to the ground pads and having a plurality of contact pads at predetermined positions on an upper surface thereof. The driving IC is connected by wire bonding in contact with the electrode pattern of the LTCC base substrate in the first space of the LTCC block, and the light emitting device is mounted in contact with the electrode pattern in the second space, and the light emitting device is mounted. 1 The inside of the space is sealed with a liquid polymer material that is cured by ultraviolet rays or heat, the package structure of the optical connection module, characterized in that the metal reflective surface is coated on the inner surface of the through hole of the through hole array formed on the LTCC substrate. A driving IC, an electrode pattern suitable for the shape of the light receiving element, a through-hole array for receiving an optical signal received by the light receiving element from an external location, and a power pad for connecting an external power source at a position where the light receiving element is mounted A low temperature co-fired ceramic (LTCC) base substrate having a ground pad formed thereon; And The electrode pattern and the power pad stacked on one surface of the LTCC base substrate and separately forming the first space for mounting the driving IC and the second space for mounting the light receiving element, respectively, for connecting to the outside from the LTCC base substrate. Or a LTCC block having a plurality of vertically penetrated via holes connected to the ground pads and having a plurality of contact pads at predetermined positions on an upper surface thereof. A driving IC is connected by wire bonding in contact with the electrode pattern of the LTCC base substrate in the first space of the LTCC block, and a light receiving element is mounted in contact with the electrode pattern in the second space and the first circuit is mounted. 1 The inside of the space is sealed with a liquid polymer material that is cured by ultraviolet rays or heat, the package structure of the optical connection module, characterized in that the metal reflective surface is coated on the inner surface of the through hole of the through hole array formed on the LTCC substrate. delete The method according to claim 1 or 2,  The metal coated on the inner surface of the through hole is a package structure of the optical connection module, characterized in that selected from Au, Ag, Cu, Al or Pt. The method of claim 1, The light emitting device package structure of the optical connection module, characterized in that it comprises a surface emitting laser (VCSEL) array. The method of claim 2, The light receiving device has a package structure of an optical connection module, characterized in that it comprises a photodiode array. Forming an electrode pattern, a ground pad, and a power pad on the LTCC base substrate in accordance with the shape of the driving IC and the light emitting device; Forming a through hole serving as a passage for transmitting an optical signal to the outside in alignment with a position where the light emitting device of the LTCC base substrate is mounted; Forming a metal reflective surface on an inner surface of a through hole formed in the LTCC base substrate; Stacking an LTCC block having a first space for mounting the driving IC and a second space for mounting the light emitting device on one surface of the LTCC base substrate;  Forming a via hole vertically penetrating a predetermined portion of the LTCC block corresponding to an electrode pattern, a power pad, and a ground pad of the LTCC base substrate; Forming a contact pad on an upper surface of the LTCC block in which the via hole is formed; Connecting a driving IC by wire bonding in contact with the electrode pattern of the LTCC base substrate in the first space, and mounting a light emitting device in contact with the electrode pattern in the second space; And The method of manufacturing a package structure of an optical connection module comprising the step of filling a liquid polymer material in the first space and curing it with ultraviolet rays or heat. Forming an electrode pattern, a ground pad, and a power pad corresponding to the shape of the driving IC and the light receiving element on the LTCC base substrate; Forming a through hole that is a passage for receiving an optical signal from the outside by aligning the light receiving element of the LTCC base substrate to a mounting position; Forming a metal reflective surface on an inner surface of a through hole formed in the LTCC base substrate; Stacking an LTCC block having a first space for mounting the driver IC and a second space for mounting the light receiving device on one surface of the LTCC base substrate;  Forming a via hole vertically penetrating a predetermined portion of the LTCC block corresponding to an electrode pattern, a power pad, and a ground pad of the LTCC base substrate; Forming a contact pad on an upper surface of the LTCC block in which the via hole is formed; Connecting a driving IC by wire bonding in contact with the electrode pattern of the LTCC base substrate in the first space, and mounting a light receiving element in contact with the electrode pattern in the second space; And The method of manufacturing a package structure of an optical connection module comprising the step of filling a liquid polymer material in the first space and curing it with ultraviolet rays or heat. delete The method according to claim 7 or 8, And forming a capacitor under the power pad as a passive element in the step of forming a power pad on the LTCC base substrate and connecting the ground pad to a ground pad.

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