KR0138846B1 - Fabrication method of packaging ultra-high speed laser diode transmission module and package structure - Google Patents

Abstract

The present invention uses a transmission line considering impedance matching in fabricating a transmission module by assembling an ultrafast laser diode, improves high frequency characteristics by reducing wire bonding points, and improves thermal characteristics using a diamond substrate. The present invention relates to a structure and a manufacturing method of a reliable ultra-fast laser diode transmission module, which is easy to manufacture due to the simplification of the assembly process by reducing the bonding point, and is formed to be a transmission line by manufacturing a pure gold thin film wire on a substrate such as planar aluminum oxide. And forming a thin film resistor at the end of the transmission line to achieve impedance matching, and attaching a diamond substrate on which all six surfaces are metallized to the final end of the transmission line to achieve effective heat transfer. N side and front of laser diode And so coupled to, and also to form a closed circuit in the electrical connection by having the p-side of the laser diode to the ground plane by a bonding wire to a large area of the ground plate.

As described above, by using a transmission line considering impedance matching according to the structure and manufacturing method of the ultra-fast transmission laser diode module according to the present invention, using a diamond substrate to improve thermal characteristics, and attaching a laser diode directly on the transmission line, Compared to the ultra-high speed laser diode module, the structure is simpler, so it is easier to manufacture, and the adaptability to the ultra-high frequency signal is excellent.

Description

Fabrication Method of Packaging Ultra High Speed Laser Dicde Transmission Module and Package Structure produced by the Method

Figure 1a is a plan view of a laser diode with the p- side on top.

1B is a side view of the laser diode.

2A is a plan view of a diamond substrate in which a portion of the entire upper surface of the metallization is coated with Au—Sn solder.

2b is a side view of the diamond substrate.

3A is a plan view of a transmission line that simultaneously performs the role of a laser diode substrate and the role of a transmission line.

3B is a side view of the transmission line.

4A is a plan view of a transmission line to which a diamond substrate and a laser diode are attached.

4B is a side view of the transmission line to which the diamond substrate and the laser diode are attached.

5A is a plan view of a mount for monitor photodiode.

5B is a side view of a mount for monitor photodiode.

5C is a rear view of the mount for monitor photodiode.

6A is a plan view of a mount of a photodiode with a monitor photodiode attached.

6B is a side view of the photodiode mount with the monitor photodiode attached.

6C is a rear view of the photodiode mount to which the monitor photodiode is attached.

FIG. 7A is a plan view of the photodiode with a monitor photodiode assembled on a transmission line with a laser diode.

7B is a side view of a state in which the photodiode with the monitor photodiode is assembled on the transmission line with the laser diode.

8A is a plan view of the dummyster mount.

8B is a side view of the dummyster mount.

9A is a plan view of a dummy mount to which a dummy is attached.

9B is a side view of the dummy mount to which the dummy is attached.

Figure 10a is a plan view of the ground plate is assembled.

Figure 10b is a plan view of the ground plate is assembled.

* Description of the symbols for the main parts of the drawings *

2: laser diode

5: diode substrate

7: side metallization of diamond substrate

9: transmission line

10: Thin Film Resistance for Impedance Matching

13: Monitor photodiode mount

16: Monitor photodiode 18: the mist mount

21: the mist 23: ground plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for packing and manufacturing a semiconductor device, and more particularly, to a package structure and a manufacturing method for die-bonding ultrafast transmission laser diodes directly on a transmission line including a transmission line.

Conventional ultra-fast transmission laser diodes have a structure that does not include a transmission line, and also has a structure where double wire bonding is performed by die bonding the laser diode on another substrate even if the transmission line is included.

The ultra-fast transmission laser diode module is not suitable as a high-speed transmission module because the inductive resistance component increases as a whole when wire bonding to a plurality of parts due to the inductance component by the bonding wire.

In particular, in order to transfer more than 10Gbps transmission speed, the inductive resistance by wire bonding should be adjusted below 0.8nH.

However, since the induction resistance of the gold wire bonding wire of 25.4 μm in diameter, which is generally used at 1 GHz or more, represents 0.7 nH per 1 mm, there is a problem in that the wire bonding portion is minimized.

Therefore, the present invention uses a transmission line in consideration of impedance matching in fabricating an ultrafast laser die assembly, and at the same time improves high frequency characteristics by reducing the location of wire bonding, and uses a diode substrate. It is therefore an object of the present invention to provide a method of manufacturing a reliable ultra-fast laser diode transmission module that is easy to manufacture by simplifying an assembly process by improving thermal characteristics and reducing wire bonding points.

In order to achieve the above object, the present invention provides the diamond substrate 5 after mounting the p-side upper laser diode 2 to the diamond substrate 5 in order to reduce the inductive resistance of the bonding wire for improving the small signal modulation bandwidth. ) Is attached to the transmission line (9); Attaching a monitor photodiode (16) to the monitor photodiode mount (13) and then attaching it to the transmission line (9); Mounting a dummyster (21) on the dummy mount (18) for detecting a temperature rise of the laser diode (2); Attaching the transfer island (9) and the dummyster mount (18) to which the grounded metal plate (23) is assembled; And wire bonding the p-side electrode of the laser diode 2 to the post 24 of the ground metal plate 22 to form a closed circuit of the laser diode 2. The structure formed by the method is characterized by the above-mentioned.

In addition, in the present invention for achieving the above object, using a conventional laser diode of the p-side up structure (p-side up structure) as it is, using a diamond substrate in the lower portion of the laser diode for effective heat dissipation In addition, since all six surfaces of the diamond substrate are metallized, the diamond substrate is electrically connected to the n-side of the laser diode to allow direct electrical connection with the transmission line.

The p-side, which is electrically grounded, is wire bonded with the bottom metallization of the transmission line to form an electrically closed circuit.

In the structure of the ultra-high-speed transmission laser diode module package according to the present invention, the inductive resistance by wire bonding can support about 0.7 nH, and thus, the ultra-high-speed transmission laser diode module can be configured.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1a and 1b show a plan view and a side view of a laser diode 2 with a p-side on the top, in the context of the invention the p-side 1 being metalized with pure gold so that it can be connected to ground. The n-side 4 is also metalized with pure gold so that it can be connected to the signal side.

The metallization thickness is about 3000 microns and the lower metal side of the laser diode is deposited Ti (1500) / Pt (3000) / Au (500).

2A and 2B show a diamond substrate 5 in which the entire upper surface is metallized and a portion is covered with Au-Su solder. In connection with the present invention, all six faces of the diamond are made of pure gold. After about 3000 deposition, the Au-Sn (6) is deposited on the upper surface.

The diamond substrate is grown by chemical vapor deposition (Chemical Vapor Deposition) is used.

The thermal conductivity of the diamond substrate 6 is 13W / cm 占 폚, which is three times higher than 3.9W / cm 占 폚 of copper.

Therefore, the heat generated from the laser diode can be effectively released.

In addition to the diamond substrate 5, a silicon carbide (SiC) substrate may be used.

3A and 3B show a transmission line 9 which serves as a substrate of the laser diode 2 and at the same time serves as a transmission line. An aluminum oxide or aluminum nitride substrate having a thickness of 0.635 mm in accordance with the present invention. In the case of 25 mW and 50 mW respectively, the substrate metal 11 is formed to have a width of 0.381 mm and 1.194 mm.

The reason for forming as above is that the input impedance of the laser diode transmission module may be 25 kHz or 50 kHz depending on the transmission system.

As described above, when the internal resistance of the laser diode is 7 kW during the process of forming the substrate metal, the thin film resistor 10 is formed to be 18 kW or 43 kW for impedance matching.

Since the thermal conductivity of aluminum oxide is about 0.2 times higher than 0.2W / cm ° C., aluminum nitride should be used to improve thermal characteristics.

The substrate back side of the microstrip line plated pure gold over the entire substrate.

4A and 4B show the transmission line 9 to which the diamond substrate 5 and the laser diode 2 are attached. The diamond substrate 5 and the laser diode 2 are related to the present invention. The process temperature at the time of attaching the to the transmission line 9 is 305 ± 5 ℃.

In order to attach the diamond substrate 5 and the transmission line 9, the diamond substrate 5 is attached with an epoxy containing silver (H20E between Epo Tek).

At this time, the curing temperature is 150 ℃, curing time is 5 minutes.

The monitor photodiode mount 13 for attaching the monitor photodiode in FIGS. 5A to 5B is shown, in the context of the present invention in which the material is aluminum oxide and on the transmission line 9 of FIG. The portion 14 and the monitor photodiode on which the monitor porter diode is to be mounted to measure the intensity of the laser beam coming out of the rear of the laser diode 2 will be assembled into a shape. The n-side and the portion 15 to be wire bonded are formed, and the electrodes on the p and n-sides extend to the top (FIG. 5a).

In order to prevent the light emitted from the laser diode 2 from being reflected back from the photodiode 16 and returning to the laser diode, it is manufactured with an inclination of 10-15 °.

6A to 6C show the monitor photodiode mount 13 to which the monitor photodiode 16 is attached, and in accordance with the present invention the photodiode 16 is mounted to the mount 13 of the monitor photodiode. In the step of attaching Au) to the n-side electrode of the photodiode 16 and the connecting electrode 15 of the mount 13 by wire bonding (17). do.

The electrodes 14 and 15 of the mount become electrodes on the p and n sides of the monitor photodiode, respectively.

7A and 7B show a state in which the completed photodiode mount 13 is assembled on the transmission line 9, and in the process of assembling as described above, silver (Ag) Curing was carried out at 150 ° C. for 1 minute using an epoxy-free (353ND from Epo-Tek).

8A and 8B illustrate a dummyster mount 18 for attaching a dummyster, and in connection with the present invention, the dummyster mount 18 for detecting a temperature rise of the laser diode 2 is shown. In the manufacturing process, the dummyster 21 is treated with pure gold on one side and soldered to allow soldering on the other side, so that the pattern of the portion to which the dummyster 21 is attached and wire bonded to the outside is It manufactures as (19) of said 8a and 8b.

In order to attach the dummyster mount 18 itself to the ground metal plate, all parts of the bottom surface are purely processed 20.

9A and 9B illustrate the state in which the dummyster 21 is attached to the dummyster mount 18. In accordance with the present invention, the dummyster 21 is connected to the dummy mound 18. FIG. ) In the step of attaching it), it is carried out at about 210 ℃ using general soldering.

10A and 10B illustrate a ground metal plate having the transmission line 9, the laser diode 2, the monitor photodiode 16, and the dummy 21 completed in FIGS. 7 and 9. As shown in Fig. 23, the transmission line 9 is attached with an epoxy 25 containing silver and the dummyster mount 18 is made of an epoxy 25 containing no silver. Attach.

In the deposition process as described above, the process temperature is performed at 150 and 120 ° C. for 5 minutes for 1 minute, and the laser diode 2 wire-bonds the p-side electrode 1 to the post 24 of the ground metal plate. The diode 2 makes it possible to electrically close the circuit.

As such, FIG. 10 shows the completeness of the ultra-high speed laser diode module considering the improved impedance and thermal characteristics.

As described above, the present invention produces a pure gold thin film lead on a substrate such as planar aluminum oxide so as to be a transmission line, and forms a thin film resistor at the end of the transmission line to achieve impedance matching, and a six-sided all-metalized diamond substrate. Adhere to achieve effective heat transfer and are electrically connected to the n side of the laser diode bonded to the substrate.

In addition, by connecting the p side of the laser diode to the ground plane of a large area by wire bonding to form a closed circuit, and the direction of the laser diode to match the transmission line so that the laser beam is emitted from the front of the module, The high frequency signal is composed of the structure which is introduced to the back of the module. It uses a transmission line substrate considering impedance matching and uses a diamond substrate to improve the thermal characteristics and attaches a laser diode directly on the transmission line. Compared with a simple structure, it is designed to be easy to manufacture and adaptable to ultra-high frequency signals, so that it can be applied to the manufacture of ultra-fast laser diode modules of 10Gbps or more, thereby improving productivity and improving performance.

Claims (6)

In the ultra-fast transmission laser diode module for improving impedance matching and characteristic improvement, With a wide ground metal plate (23): A dummy mount (18) attached to the ground metal plate (23); A dummyster 21 mounted on the dummyster mount 18; A transmission line 9 having a thin film resistor 10 attached to the ground metal plate 23; A diamond substrate 5 attached on the transmission line 9; A p-side upper laser diode (2) mounted on the diamond substrate (5); A monitor photodiode mount (13) attached on the transmission line (9); A monitor porter diode (16) mounted on the monitor photodiode mount (13); And Ultra-fast transmission laser, characterized in that the post-24 is formed by electrically bonding the p-side electrode of the laser diode 2 to the ground metal plate 23 so that the laser diode 2 is electrically closed. Diode module structure. The method of claim 1, The monitor photodiode mount (13), which is mounted on the monitor photodiode (16) and can pass on the transmission line (9), is characterized in that the c-shaped structure. The method of claim 1, In order to reduce the induction resistance caused by the bonding tire, the diamond substrate 5 on which the laser diode 2 is mounted is directly bonded on the transmission line 9 so that the location of the bonding wire is reduced. Laser diode module structure for In manufacturing a ultra-fast transmission laser diode module for improving impedance matching and improving thermal characteristics, attaching the p-side upper laser diode (2) to the diamond substrate (5) and then attaching the diamond substrate (5) on the transmission line (9); Attaching a monitor photodiode (16) to the monitor photodiode mount (13) and then attaching it to the transmission line (9); Mounting a dummyster (21) on the dummyster mount (18) for detecting a temperature rise of the laser diode (2); And And a step of attaching the assembled transmission line (9) and the dummy mount (18) to a wide ground metal plate (23). In Figure 4, In order to reduce the induction resistance caused by the bonding wire, the diamond substrate 5 on which the laser diode 2 is mounted is directly bonded to the transmission line 9 to reduce the location of the bonding wire. Method of manufacturing a laser diode module. The method of claim 4, wherein Ultra-fast transmission, comprising a step of wire bonding the p-side electrode of the laser diode 2 to the post 24 of the ground metal plate 23 to form a closed circuit of the laser diode 2. Method of manufacturing a laser diode module.