KR20030046778A - Package structure of optical device and method of manufacturing thereof - Google Patents

Abstract

PURPOSE: An optical semiconductor device package structure and a fabricating method therefor are provided to improve the radiative performance of an optical semiconductor device by using a base plate having thermal conductive holes and a plurality of thermal conductive layers. CONSTITUTION: An optical semiconductor device package structure(30) includes a substrate(31), a sidewall portion formed on an edge of the substrate, and a conductive pad(36) for connecting an optical semiconductor device with the outside. The substrate includes a base plate(32) including alumina as the chief ingredient and plural thermal conductive holes and one or more thermal conductive layers. The thermal conductive layers are formed on an upper portion or a lower portion of the base plate. The thermal conductive layers are formed with the first thermal conductive layer(41a41b,41c), the second thermal conductive layer(42a,42b), and the third thermal conductive layer(43a,43b).

Description

Package structure of optical device and method of manufacturing

The present invention relates to an optical semiconductor device package structure and a method for manufacturing the same, and more particularly, to an optical semiconductor device package structure having a heat dissipation structure capable of providing thermal stability of an optical semiconductor device embedded in a ceramic package mainly composed of alumina, and It relates to a manufacturing method.

Electrical devices that electrically process signals are gradually increasing the use of optical semiconductor devices as communication devices due to the weakness of signal transmission and processing speed and weak noise compared to optical signals.

Optical semiconductor devices include various known devices such as semiconductor laser diodes, semiconductor optical amplifiers (SOAs), and optical switch devices.

The optical semiconductor device component packages a chip manufactured through a conventional semiconductor device manufacturing process for manufacturing a semiconductor device through a packaging process.

1 is a schematic exploded perspective view showing a separate packaged general laser diode device.

Referring to the drawings, the laser diode element 20 is embedded in the package structure 10.

The package structure 10 includes a substrate 11 on which the laser diode element 20 is mounted, a sidewall 13 and a cap 17 formed at a predetermined height from an edge of the substrate 11.

Reference numeral 16 is a conductive pad wire-bonded with the laser diode element 20, reference numeral 18 is a lead frame 18 coupled to the conductive pad from the outside, and reference numeral 19 is light emitted from the laser diode element 20. It is a light exit tube for emitting light to the outside.

In the light emitting tube 19, a collimating lens (not shown) may be installed to focus the light emitted from the laser diode element 20 into a parallel beam.

The conventional package structure 10 for embedding the laser diode device 20 is made of alumina material, that is, ceramic material, which is inexpensive and has insulation.

That is, referring to FIG. 2, which shows a cross-sectional view of a package structure shown in a cut state along the line II-II ′ of FIG. 1, the package structure 10 includes a laser diode device 20. The board | substrate 11 to be mounted and the side wall part 13 formed in the predetermined height from the board | substrate 11 were formed from the ceramic material which has alumina as a main component.

In general, when the operating temperature of the laser diode device 20 increases by 10 degrees (° C.) above the rated operating temperature, the life is shortened to half or less. In particular, the recent optical communication system is applying a transmission rate of more than 10Gbps (Giga bite per second) per channel, in the case of the optical communication laser diode applied to the heating frequency is further increased with the increase in the switching frequency, it is appropriate to increase the heat generation Adoption of a heat dissipation structure is required.

In addition, the allowable oscillation wavelength of the laser diode in the ultrafast optical communication system is more strictly limited. Therefore, in consideration of factors such as temperature dependence of the oscillation wavelength of an optical semiconductor device such as a laser diode and an increase in the amount of heat generated by high-speed switching, a package of a high efficiency heat dissipation structure capable of providing a rated operating temperature is required.

However, the ceramic material used as the conventional substrate 11 has a thermal conductivity of about 12 (W / m ° k), which is lower than that of general metals. Therefore, when used as a package material of an optical semiconductor device such as a laser diode having a high temperature dependence of the oscillation wavelength, there is a disadvantage in that the output of the optical semiconductor device that can be mounted is limited within a certain range because of low heat dissipation characteristics.

In order to improve this, the size of the substrate 11 of the package may be expanded to appropriately dissipate heat generated when the optical semiconductor device is driven to the outside, or the entire substrate 11 may be replaced with a metal material having high thermal conductivity. There is this.

However, the method of expanding the size of the substrate 11 is counteract to the miniaturization of components, and there is a burden on the price increase to replace the metal material having high thermal conductivity. Particularly, when the entire substrate 11 is replaced with a metal material, defects may occur when the metal substrate and the sidewall portion of the alumina material are bonded to each other, and such defects may decrease the joint strength and weaken durability. There is a problem that can lead to a decrease in yield.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide an optical semiconductor device package structure and a method of manufacturing the same, which can alleviate the increase in heat dissipation capability and the increase in durability and manufacturing cost.

1 is a schematic exploded perspective view showing a separated typical laser diode device packaged,

FIG. 2 is a cross-sectional view of a conventional package structure shown along the line II-II ′ of FIG. 1 with respect to the packaged structure of FIG. 1, FIG.

3 is a cross-sectional view of an optical semiconductor device package structure according to a preferred embodiment of the present invention,

4 is a flowchart illustrating a process of manufacturing an optical semiconductor device package according to a preferred embodiment of the present invention.

FIG. 5 is an exploded perspective view illustrating separated elements stacked by the lamination process of FIG. 4;

6A through 6D are cross-sectional views illustrating a package structure that has been partially processed to explain the manufacturing process of FIG. 4.

<Description of the reference numerals for the main parts of the drawings>

30: package structure 31: substrate

32: base plate 32a: heat conduction hole

33: side wall portion 36: conductive pad

39: cap 41: first thermal conductive layer

42: second thermal conductive layer 43: third thermal conductive layer

60: optical semiconductor device

In order to achieve the above object, an optical semiconductor device package structure according to the present invention comprises a substrate, a side wall portion formed at a predetermined height at the edge of the substrate to form an inner space for seating the optical semiconductor device and the optical semiconductor device; An optical semiconductor device package structure having conductive pads penetrating into and out of the sidewall portion for connection to an external device, the substrate comprising: a base plate formed of alumina as a main component and having a plurality of heat conductive holes; And a material having a higher thermal conductivity than the alumina material, and at least one thermal conductive layer formed in a predetermined thickness on the upper and lower portions of the base plate through the thermal conductive holes.

Preferably, the thermally conductive layer comprises: a first thermally conductive layer filling the thermally conductive hole with at least one of tungsten and molybdenum / manganese, and formed up to and below the base plate; Second heat conductive layers formed of nickel on upper and lower portions of the first heat conductive layer; And a third heat conductive layer formed of a gold material on the upper and lower portions of the second heat conductive layer.

The side wall portion is preferably formed of the same material as the base plate.

In addition, in order to achieve the above object, a method of manufacturing an optical semiconductor device package structure according to the present invention includes a base plate made of alumina and a heat conduction hole formed through the base plate to fill the upper and lower portions of the base plate. Forming a primary structure having a first thermal conductive layer formed on the sidewall and sidewalls formed at a predetermined height to form an inner space in which the optical semiconductor device may be embedded; Forming a second heat conductive layer on the top and bottom of the first heat conductive layer with a nickel material; And forming a third heat conductive layer of a gold material on the top and bottom of the second heat conductive layer.

Preferably, the primary structure comprises the steps of forming a predetermined number of thermally conductive holes in at least one green sheet to be applied to the base plate; Forming a first thermal conductive layer of a predetermined material having a higher thermal conductivity than the alumina material in the upper and lower portions of the base plate to fill the thermal conductive holes; Stacking a green sheet for the side wall portion having a conductive pad formed on the base plate; Firing the laminated green sheet structure.

In addition, the first thermal conductive layer is formed of at least one material of tungsten, molybdenum / manganese.

Hereinafter, an optical semiconductor device package structure and a manufacturing method thereof according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of an optical semiconductor device package structure according to a preferred embodiment of the present invention.

Referring to the drawings, the optical semiconductor device package structure 30 includes a substrate 31 and sidewalls 33.

The substrate 31 includes a base plate 32, a first heat conductive layer 41, a second heat conductive layer 42, and a third heat conductive layer 43.

The base plate 32 is formed of a ceramic material with alumina (Al ₂ O ₃ ) as a thickness to ensure sufficient supporting force. As an example, the base plate 32 is formed to a thickness of about 0.5 to 1mm. The base plate 32 has a plurality of heat conduction holes 32a formed therethrough.

First and second conductive layers 41 are formed in the upper and lower portions of the base plate 32 so as to penetrate the thermal conductive holes 32a. That is, the first heat conductive layer 41 is divided into an upper first heat conductive layer 41a, a through first heat conductive layer 41c, and a lower first heat conductive layer 41b.

The first thermal conductive layer 41 has a thermal conductivity of several to tens of times higher than that of the alumina material, and is inexpensive compared to other metal materials, and has a good bonding force with the alumina material (W) (178 (W / m ° K)). , Molybdenum / manganese (Mo / Mn) is preferably formed of at least one material. The upper first thermal conductive layer 41a and the lower first thermal conductive layer 41b are each formed to an appropriate thickness, for example, a thickness of about 5 to 40 μm.

The second thermal conductive layer 42 is formed on the lower portion of the upper and lower first thermal conductive layers 41b of the upper first thermal conductive layer 41a formed to extend to the upper and lower portions of the base plate 32 through the thermal conductive holes 32a. Each is formed. The second thermal conductive layer 42 may suppress diffusion into other layers of the material of the third thermal conductive layer 43 and the first thermal conductive layer 41 and the third thermal conductive layer 43 during plating of the third thermal conductive layer 43, which will be described later. It is formed of a material having an appropriate bonding force for each of the layers 41 and 43 so as to mediate the bonding. Preferably, the second thermal conductive layer 42 is formed of nickel (Ni) (90 (W / m ° K)) material.

The upper and lower second thermal conductive layers 42a and 42b are each formed to have a predetermined thickness, for example, about 1.27 to 10 μm.

The second thermal conductive layer 42 may be formed only on the upper first thermal conductive layer 41a.

The third thermal conductive layer 43 is formed on the upper portion of the upper second thermal conductive layer 42a and the lower portion of the lower second thermal conductive layer 42b, respectively, and is a die bonding material of a generally used optical semiconductor element. It is formed of a gold material having a good bonding force with a phosphorus / tin (Au / Sn) alloy.

The upper and lower third thermal conductive layers 43a and 43b are each formed to have a predetermined thickness, for example, about 0.1 to 2 μm thick.

The third thermal conductive layer 43 may also be formed only on the upper second thermal conductive layer 42a.

The optical semiconductor element is bonded to the upper surface of the upper third thermal conductive layer 43a by a bonding material through a soldering process. As the soldering bonding material, an epoxy material may be applied in addition to the material described above, that is, a gold / tin alloy.

The side wall portion 33 is formed at a predetermined height upward from the edge of the base plate 32. An internal mounting space for mounting the optical semiconductor element is formed by the base plate 32 and the side wall portion 33.

The side wall portion 33 is preferably formed of the same material as the base plate 32, that is, a ceramic material mainly composed of alumina.

The side wall portion 33 is stepped so that a predetermined height portion from the base plate 32 may be seated through the inside and outside of the side wall portion 33 for the conductive pad 36 for connecting the lead frame and the optical semiconductor elements to each other. have. That is, the side wall portion 33 has a cross-sectional area greater than that of the first portion 33a so that the first portion 33a formed above the predetermined height from the base plate 32 and a portion of the upper surface of the first portion 33a are exposed. The second surface 33 is formed to be narrow but has an outer side surface formed to be parallel to the first portion 33a.

The stepped exposed surface 33c serving as an interface between the first portion 33a and the second portion 33b is formed such that the conductive pad 38 penetrates inside and outside the sidewall portion 33.

The conductive pad 36 is connected by wire bonding with a corresponding electrode of the optical semiconductor device mounted on the third thermal conductive layer 43. The conductive pad 36 is preferably formed of tungsten or molybdenum / manganese (Mo / Mn) alloy.

After bonding and wiring of the optical semiconductor device are performed, the upper surface of the sidewall part 33 is sealed. For example, a KOVAR plate or a nickel-iron alloy (Ni-Fe) plate plated with gold (Ni + Au) on a gold or nickel layer, or a ceramic cap ( Cap Seal with Sealing or Soldering using Ceramic Cap.

The package structure 30 appropriately determines the diameter and number of the thermally conductive holes 32a and the stacking thickness of each of the thermally conductive layers 41 to 43 to suit the heat generation characteristics of the optical semiconductor device to which the optical semiconductor device is applied. It is possible to provide an optimal heat dissipation structure for.

A preferred manufacturing process of such a package structure will be described in more detail with reference to FIGS. 4 to 6.

First, a thermally conductive hole is formed in at least one green sheet to be applied as the base plate (step 100).

Here, the green sheet refers to a flexible thin sheet-shaped alumina plate composed of more than 90% by weight of alumina. The green sheet is generally used to manufacture a multilayer ceramic substrate for a known integrated circuit, and the base is hardened through a post-process firing process. It becomes the plate 32. Methods of making such green sheets are known. For example, the green sheet refers to a sheet produced by sheet casting the alumina slurry subjected to the vibration defoaming process to have a target viscosity. The alumina slurry is mixed with an alumina (Al2O3) powder by adding an aqueous solvent, a plasticizer, a humectant, and a peptizing agent to a sintering aid composed of impurities such as SiO2, MgO, and CaO, and then adding and mixing a binder and an antifoaming agent with a predetermined capacity. Is generated. Typically, the aqueous solvent is water, the plasticizer is polyethylene glycol and butyl benzyl phthalate, the wetting agent is a nonionic oxyl phenolic ethynol, the peptizing agent is yl sulfonic acid, the binder is an acrylic resin emulsion, the antifoam agent is a wax emulsion. do.

Next, the metallization pattern of the green sheet processed to correspond to the package structure is applied to the green sheet selected as the object to be printed with the corresponding metal paste (step 110).

Preferably, the first thermal conductive layer 41 and the conductive pad 36 are applied to the corresponding green sheet with a metal paste of the material.

Thereafter, the green sheets subjected to the hole processing and the metal paste coating process are sequentially stacked to correspond to the shape of the target structure (step 120). Referring to FIG. 5, which shows an example of the stacked structure, the green sheet group for the base plate 32 on which the plurality of green sheets having the heat conduction holes 32 a are formed is stacked, and the uppermost green sheet group of the green sheet group for the base plate. For the first portion 33a of the sidewall portion 33 on which the first thermal conductive layers 41a and 41b and the conductive pad 36 layer are formed, which are applied to the lower portion of the lowermost green sheet through the thermally conductive holes 32a in some regions. The green sheet group and the green sheet group for the second portion 33b are sequentially stacked. In the green sheet group for the second portion 33a, a hole for forming a light exit tube is formed.

The laminated structure thus laminated is calcined by heating and pressing under known conditions such that the sheets and metal pastes can be bonded and sintered together (step 130). Through certain processes, the green sheets are sintered with each other by a thermoplastic binder to form a basic structure having hard hardness.

Through this firing process, a basic structure as shown in FIG. 6A is primarily formed.

Thereafter, a second thermal conductive layer 42 is formed (step 140). The second thermal conductive layer 42 is formed by plating a predetermined thickness on the upper portion of the upper first thermal conductive layer 41a and the lower portion of the lower first thermal conductive layer 41b using the materials described above.

After the formation of the second thermal conductive layer 42, the lead frame 38 is attached to the conductive pad 36 by the bonding material 52 through a soldering process (see FIG. 6B). The process of attaching the lead frame 38 may be performed during subsequent steps.

Then, a third thickness of the third heat conductive layer 43 is formed of a gold material (see FIG. 6C) (step 150).

The optical semiconductor device 60 is attached to the upper third thermal conductive layer 43a of the structure formed up to the third thermal conductive layer 43 by a bonding material 53 such as a gold / tin alloy or an epoxy material through a soldering process. (See FIG. 6C) (step 160).

Subsequently, the conductive pads 36 corresponding to the electrodes of the optical semiconductor element 60 mounted on the third thermal conductive layer 43 are bonded by wires 70 (step 170) and correspond to the base plates 32. A cap 39 having an area to be attached is attached to the upper surface of the side wall portion 33 using a sealing paste 54 such as a sealing agent 54 made of gold / tin (see FIG. 6E) (step 180).

In the above description, the process in which the conductive pad 36 is bonded to the green sheet structure laminated before the firing process has been described. However, before the firing process, only the conductive pad penetrating holes penetrating into and out of the sidewall are formed, and then the conductive pad is formed after the firing process. Of course, the 36 can be attached through the through hole.

In addition, although the processing is somewhat difficult, after forming the thermally conductive holes 32a after the firing process, the first to third thermally conductive layers 41 to 43 may be sequentially formed.

As described so far, according to the optical semiconductor device package structure according to the present invention and a method for manufacturing the same, formed of a material having a higher thermal conductivity than the alumina material above and below the base plate so as to pass through the heat conductive holes formed in the base plate of the alumina material. It is possible to improve the heat dissipation ability of the optical semiconductor device embedded through the thermal conductive layer. In addition, the supporting structure and the basic structure of the package is formed of alumina material, but the diameter and number of the heat conduction holes and the thickness of the heat conduction layer can be appropriately adjusted according to the heat generation characteristics of the applied optical semiconductor device, so that each of the optical semiconductor devices of various outputs is provided. It is possible to provide an optimal heat dissipation structure for. In addition, the heat conduction layer is formed by being supported to be supported on the upper and lower portions of the base structure through heat conduction holes formed in the base structure made of alumina material, thereby improving durability.

In addition, the cost of the thermal conductive layer material relative to the alumina material is relatively small, there is an advantage that the increase in manufacturing cost of the package structure is not large.

Claims (5)

A sidewall portion formed at a predetermined height at an edge of the substrate to form an inner space for seating the optical semiconductor element, and a conductive pad formed penetrating the inside and the sidewall portion for connection between the optical semiconductor element and the outside; In the optical semiconductor device package structure provided, The substrate is A base plate formed of alumina as a main component and having a plurality of heat conductive holes; And a material having a higher thermal conductivity than the alumina material, and at least one thermally conductive layer formed on the upper and lower portions of the base plate through the thermally conductive holes to have a predetermined thickness. The method of claim 1, wherein the thermally conductive layer is filled with at least one material of the tungsten, molybdenum / manganese, the first thermal conductive layer formed to the upper and lower portions of the base plate; Second heat conductive layers formed of nickel material on upper and lower portions of the first heat conductive layer; And And a third thermal conductive layer formed of a gold material on the upper and lower portions of the second thermal conductive layer. In the manufacturing method of the optical semiconductor device package structure, The optical semiconductor device may be embedded in an alumina-based base plate, a first heat conductive layer formed on the upper and lower portions of the base plate, and an upper portion of the base plate to fill the heat conduction holes formed through the base plate. Forming a base structure having sidewall portions formed to a predetermined height to form an internal space; Forming a second thermal conductive layer of nickel material on the upper and lower portions of the first thermal conductive layer of the basic structure; And forming a third thermal conductive layer of gold on upper and lower portions of the second thermal conductive layer. The method of claim 3, wherein the basic structure Forming a predetermined number of thermally conductive holes in at least one green sheet to be applied to the base plate; Forming a first thermal conductive layer of a predetermined material having a higher thermal conductivity than the alumina material in the upper and lower portions of the base plate to fill the thermal conductive holes; Stacking a green sheet for the side wall portion having a conductive pad formed on the base plate; Firing the laminated green sheet structure; manufacturing method of an optical semiconductor device packaging structure comprising a. The method of claim 4, wherein the first thermal conductive layer is formed of at least one of tungsten and molybdenum / manganese. 6.