KR100857790B1 - LED lighting device and package and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a light emitting diode lighting apparatus, a package, and a method for manufacturing the same. The present invention provides an electrode for flip chip bonding after forming a through hole on a silicon sub-mount, and forming an electrode connected to the LED electrode on the front surface. Forming on the rear side, the electrodes are connected to each other through the through-hole, so that the sub-mount in which the LED is placed can be bonded to the stem in which the electrode wiring for the LED power supply is formed by flip chip bonding, thereby reducing the process time and cost and The reliability can be greatly increased, and since the stem and the LED electrode are directly connected through the electrode passing through the through hole, the heat dissipation effect is greatly increased, thereby improving the lifespan and characteristics of the device.

Light emitting diodes, submounts, electrodes, through holes, LEDs.

Description

LIGHT EMITTING DIODE LIGHTING APPARATUS AND PACKAGE THEREFOR AND MANUFACTURING METHOD FOR MAKING THE SAME}

1 is a cross-sectional view showing a backlight structure of a thin film transistor LCD.

2 is a cross-sectional view of a general light emitting diode.

3A to 3G are cross-sectional views illustrating a process of manufacturing a light emitting diode package according to an embodiment of the present invention.

Figures 4a to 4c is a perspective view showing a manufacturing process of the lighting device of an embodiment of the present invention.

5A to 5C are cross-sectional views illustrating a process of manufacturing a light emitting diode package according to another embodiment of the present invention.

6 is a cross-sectional view of a lighting device including the package manufactured through FIGS. 5A-5C.

7a to 7d is a cross-sectional view showing a manufacturing process of a light emitting diode package according to another embodiment of the present invention.

8 is a cross-sectional view of a lighting device including the package manufactured through FIGS. 7A-7D.

9A to 9C are cross-sectional views illustrating a process of manufacturing a light emitting diode package according to another embodiment of the present invention.

10 is a cross-sectional view of a lighting device including the package manufactured through FIGS. 9A-9C.

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

20: light emitting diode 30: package

31 substrate 32 mask layer

33: insulating layer 34: first electrode

35 solder layer 36 second electrode

40: stem 41: stem insulating layer

42: electrode wiring layer 43: stem solder layer

The present invention relates to a light emitting diode lighting device and a package and a method of manufacturing the same, and more particularly, to a light emitting diode lighting device and a package and a method of manufacturing the same that can be formed by aligning the package in which the light emitting diode is arranged.

In general, the light emitting device has been used as a display device using simple light emission, but recently, the possibility of a light source having various wavelengths and energy has been studied. Currently, active light emitting devices are classified into laser diodes (LDs) and light emitting diodes (LEDs). LDs are widely used as light sources in the optical communication field. In addition, the application area is gradually becoming diverse, such as being applied to backlight devices of lighting devices or LCD displays.

In particular, LEDs can operate at a relatively low voltage, but have a low heat generation and a long lifespan due to high energy efficiency.As a result, technologies that can provide white light with high brightness, which have been difficult to implement in the past, have been developed one after another. Is expected to be the dream technology to replace the lighting device.

Research is being actively conducted to arrange such LEDs in an array and use them as backlights of display devices that are difficult to emit light. In particular, it is expected to be a backlight light source that can replace the cold cathode tube (CCFL) used in thin film transistor (TFT) LCD, which is rapidly increasing in use.

TFT LCD is a device that realizes color by changing the transmittance of light by changing the direction of liquid crystal according to the voltage applied between a pair of transparent electrodes facing in parallel. Large area is possible, and it is gradually replacing CRT (Chathod Ray Tube). However, since the TFT LCD does not emit light by itself unlike a plasma display panel, an electroluminescent display device, or a CRT, a backlight unit for supplying light to a display device is required. The backlight unit is a surface light source generator that allows the light emitted from the light emitting unit to be spread evenly throughout the panel.

1 is a cross-sectional view showing a structure of a general backlight unit 10, and is made of a multi-layer as shown in the drawing, the light is uniformly spread by receiving the light of the light source 8 to emit light from the side of the backlight unit Is supplied to the LCD panel 1 above the backlight unit 10.

The backlight unit 10 is formed on one side of the light guide plate 6 and the light guide plate 6 that receives the light provided from the light source 8 and scatters the light received by the glass material formed therein to reflect the light. The reflective plate 7, the diffuser plate 5 positioned at the other side of the light guide plate 6 to scatter the light provided from the light guide plate 6, and the light diffused through the diffuser plate 7 can be spread evenly. It consists of a vertical / horizontal prism 4,3 arranged at right angles and a protective layer 2 disposed on the vertical / horizontal prism 4,3.

The light source 8 generally uses a cold cathode tube (CCFL) that generates a small amount of heat and provides even light emission. However, due to a high driving voltage and high power consumption, LEDs, which are point light sources, are arranged in a line, like a line light source. Also used. By arranging LEDs as a line light source, manufacturing cost, driving power, and power control unit size are greatly reduced, and the brightness of the display unit is also comparable to that of the CCFL light source due to the provision of increasingly high brightness LEDs.

FIG. 2 is a cross-sectional view illustrating a structure of a general LED used as a backlight light source, and a buffer layer 22 and an n-contact layer are sequentially formed on a substrate 21 such as sapphire or n-GaAs, as shown. (23), the active layer 24 and the p-contact layer 25 are continuously deposited by chemical vapor deposition, and patterned to expose the n-contact layer 23 by a photolithography process and a wet / dry etching method. . Thereafter, the insulating layer 26 is deposited on the formed structure and patterned to expose the p-contact layer 25 on the structure and a portion of the n-contact layer 23 exposed in the above process for electrical connection. Then, a metal is formed on the exposed p-contact layer 25 and n-contact layer 23 after patterning to form a p-electrode 27 and an n-electrode 28.

The light emitting diode configured as described above emits light by applying a voltage between the p-electrode 27 and the n-electrode 28, and when a voltage is applied, holes are formed into the p-electrode 27 and the n-electrode 28. And electrons are injected and holes and electrons are recombined in the active layer 24 to emit light to the outside.

The LED formed in the chip state may be directly applied on a substrate, and may be attached to various packages (epoxy molding, can-type package). However, when formed in the epoxy molding type, the light efficiency is lowered by the epoxy, it is difficult to obtain an even light emission effect, and it is difficult to dissipate the generated heat to the outside. And because of its large size, compact placement is difficult. When used in a can-type package (TO-can), the size of the package is large, which makes it difficult and dense to form a line light source. Therefore, a method of forming an electrode pattern on a printed circuit board and directly attaching an LED chip to the pattern, and then connecting the electrode by wire bonding is mainly used. It takes a long process time, generates bad defects, and has low reliability. The technique powers the LEDs, resulting in lower yields and higher costs. In addition, since the printed circuit board has low heat transfer efficiency, it is difficult to effectively dissipate heat generated when the LED device is driven, thereby lowering the lifespan and changing characteristics of the device.                         

Therefore, in recent years, after the LED sub-mount is formed using a semiconductor process, LEDs are connected to the sub-mounts, and packages with LEDs are arranged and used on stems having high heat transfer efficiency. However, a general package forms an electrode layer connected to an LED electrode on a silicon substrate to arrange an LED on the electrode layer, and connects the electrode wiring for external power supply and a wire bonding technique using the extended electrode layer as a wire bonding pad. To do that. In this case, the heat generated from the LED is dissipated to the stem via the silicon sub-mount, so the heat dissipation efficiency is higher than that of the direct bonding on a general printed circuit board, and a wide wire bonding pad can be used to facilitate the process.

However, even in the case of using a conventional package, a low yield wire bonding must be used for connection with an external power source, resulting in a high defect rate, a long process time, and a low overall reliability. In addition, since the heat generated during driving of the device is transferred to the stem via the silicon substrate forming the sub-mount, smooth heat dissipation is difficult to expect, which may reduce the lifespan and change of characteristics of the device due to heat generation.

As described above, when the LEDs are arranged and used as a lighting device such as a backlight, it is difficult to implement the lighting device as a packaged LED due to size, light uniformity, and cost, and a printed circuit board in the form of a chip. In the case of using directly attached to the phase, a precise wire bonding process is required, and thus there is a problem that the yield and reliability deteriorate.
In addition, even when the LED is attached to the stem after the recently proposed silicon sub-mount, the wire bonding process is essential for external power supply, so the yield and reliability are low, and the heat dissipation through the silicon is low and the efficiency is sufficient. There was a difficult heat dissipation.

In view of the above problems, the present invention improves process time, cost and reliability by eliminating low-yielding, low-cost and high-cost wire bonding, and provides a heat dissipation effect as the stem and the LED electrode are directly connected to the electrode passing through the through hole. It is an object of the present invention to provide a light emitting diode lighting apparatus and a package and a method of manufacturing the same.

The present invention for achieving the above object is a light emitting diode lighting apparatus in which a plurality of light emitting diodes are arranged to act as a line light source or a surface light source, the stem and the power wiring for supplying power to the light emitting diode and ; The first electrode formed on the front surface of the substrate to be connected to the light emitting diode electrode and the second electrode formed on the back surface of the substrate for flip chip bonding are connected through a through hole on the substrate. A flip chip bondable sub-mount; It characterized in that it comprises a light emitting diode bonded on the first electrode of the front portion of each sub-mount.

The present invention also provides a method for forming a through hole for each region of a silicon substrate to be used as a submount; Forming an insulating layer on the entire surface of the formed structure, and then forming a first electrode including a region where an electrode of the light emitting diode is to be located and at least a portion of the through hole; Flipping the structure and extending from a portion for flip chip bonding to form a second electrode in contact with at least a portion of the through-holes in which the first electrode is formed; Cutting the structure by sub-mounts, and then bonding a light emitting diode to the first electrode; And aligning and flip-chip bonding the sub-mount on which the light-emitting diode is formed to a stem on which electrode wiring for providing light-emitting diode power is formed.

The forming of the through hole may include forming a groove in which a light emitting diode may be disposed by bulk etching a portion of the silicon substrate, and applying a photoresist pattern to the back surface of the substrate structure and dry etching to form a vertical through hole. It characterized in that it further comprises.

The forming of the through hole and the first electrode may include forming a first electrode on the substrate first, and then etching the through hole in a bulk etching manner so as to expose the first electrode.

The forming of the through hole may include forming a through hole by firstly etching a portion of the upper part or the lower part by a bulk etching method and then secondly etching the opposite side by a bulk etching method.                     

DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiments of the present invention implemented as described above will be described in detail with reference to the accompanying drawings.

3A to 3G are cross-sectional views illustrating a manufacturing process of a package used in an embodiment of the present invention. As shown in FIG. 3A to 3G, a groove is formed on a portion where a light emitting diode (LED) 20 is to be formed. A through hole is formed in the structure in which the first electrode 34 and the second electrode 36 are connected.

First, as shown in FIG. 3A, a mask layer is formed on the silicon substrate 31 or a mask pattern necessary for bulk etching the LED mounting region is formed using the silicon substrate 31 on which the mask layer is already formed.

Next, as shown in FIG. 3B, a portion of the silicon substrate 31 is bulk etched (bulk micromachining) using the mask pattern. In the present embodiment, through the bulk etching process, grooves having a predetermined angle are formed for each region where the LED is to be disposed, and the depth thereof is deeper than the height of the LED to be mounted thereafter, so as to minimize the light leaking out to the side. . In some cases, the light emitting efficiency can be improved by sequentially forming a reflective layer and an insulating layer on the substrate.

Next, as shown in FIG. 3C, a first photoresist PR1 for protection is formed on the structure, and the structure is turned over to form a second photoresist pattern PR2. The first photoresist PR1 is intended to prevent the substrate from being damaged by the dry etching gas when the etching is completed.

Next, as illustrated in FIG. 3D, the silicon substrate 31 is dry-etched using the second photoresist pattern PR2, and an insulating layer 33 for electrical insulation is formed on the entire surface of the structure. The dry etching forms a vertical through hole by a deep reactive ion etching process, and the insulating layer 33 may use a general insulating film such as a silicon oxide film or a silicon nitride film.

Next, as shown in FIG. 3E, a first electrode 34 for connecting to the LED electrode to be bonded later is formed on the structure, and a solder layer 35 is formed thereon. The first electrode 34 is formed by performing one of various metal processes on a part to be connected to the LED electrode, a through hole part, and a part requiring electrical connection, and the first electrode 34 is formed on at least a part of the through hole. Should be.

Next, as shown in FIG. 3F, the structure is turned over to form a second electrode 36 including a portion for flip chip bonding and a through hole portion in which the first electrode 34 is formed, as one of various metal processes. . As a result, since the first electrode 34 and the second electrode 36 are connected to each other, power can be provided to the LED electrode through flip chip bonding.

Next, as shown in FIG. 3G, the structure is cut in the unit of the package 30 and then the LEDs are formed on the solder layer 35 formed on the first electrode 34 of each sub-mount 30. 20) is placed and heat treated to bond.

4A to 4C illustrate a process of bonding the LED package 30 to the stem 40 on which the electrode wiring 42 for supplying LED power according to an embodiment of the present invention is formed.

First, as shown in FIG. 4A, the stem insulating layer 41, such as a ceramic thin film, is formed on the conductive stem 40, and the electrode wiring layer 42 for supplying LED power is formed on the conductive stem 40. It is prepared through a separate process. In this embodiment, the wirings for driving all the LEDs in parallel are formed, but the wirings for driving the individual LEDs or the LEDs in a predetermined combination may be formed. In addition, if the stem 40 is an insulator, the stem insulating layer 41 may not be formed.

Next, as shown in FIG. 4B, a stem solder layer 43 for bonding is formed on the sub-mount connection portion on the electrode wiring layer 42.

Next, as shown in FIG. 4C, the package 30 on which the LED is mounted is aligned on the stem solder layer 43, and then heat-treated to perform bonding.

According to the shape of the electrode wiring layer 42 can be attached to the package 30 to which the LED is bonded in a variety of alignment manner can form a lighting device for a variety of uses.

In particular, since the present embodiment has a package structure capable of eliminating optical interference with adjacent LEDs while improving the luminous efficiency of the LED, excellent light quality can be obtained, and since the flip chip bonding structure according to the present invention is provided, it is simple and collectively. The package can be mounted on the stem in a reliable and reliable manner. In addition, since the connected second electrode for flip chip bonding is directly connected to the LED electrode, heat generated when the LED is driven can be quickly transferred to the stem 40, thereby providing excellent heat dissipation effect.

As described above, the present invention may be applied to various structures using through-holes to form a package to enable flip chip bonding in an illumination device formed of an LED array.

5A to 5C are cross-sectional views illustrating a manufacturing process of another embodiment of the present invention, in which a first electrode layer 34 is first formed on a silicon substrate 31 on which an insulating layer 33 is formed, as shown in FIG. 5A. Subsequently, as shown in FIG. 5B, the silicon substrate 31 is micro-machined from the rear side to form through holes, thereby exposing the first electrode 34 and flip chip bonding to the back side of the silicon substrate 31. The second electrode 36 is formed to at least a part of the formed through hole to electrically connect the first electrode 34 and the second electrode 36. In this way, the through hole is formed by the bulk micromachining technique, which facilitates the process and reduces the cost.

Through the above structure, the first electrode 34 and the LED electrode to be mounted can be basically connected, which is joined to the electrode wiring formed on the stem by the second electrode 36 connected to the first electrode 34. The voltage applied through the electrode wiring can be transferred to the LED electrode.

Next, as shown in FIG. 5C, solder layers 35 for bonding are formed on the electrodes 34 and 36. Although not shown, after cutting the structure for each package, the LED is disposed on the solder layer 35 on the first electrode 34 and then heat-treated to perform bonding.

FIG. 6 shows the package formed in FIGS. 5A to 5C mounted on the stem 40 on which the electrode wiring 42 is formed. Through this, it is possible to form a lighting device for various uses.

7A to 7D are cross-sectional views illustrating a manufacturing process of another embodiment of the present invention. As shown in FIG. 7A, a lower portion of the silicon substrate 31 on which the insulating layer 33 is formed is removed through a bulk micromachining process. To form grooves.

Next, as shown in FIG. 7B, a portion of the groove is dry-etched to form a vertical through hole.

Next, as shown in FIG. 7C, a first electrode 34 including a portion where the LED electrode is to be formed and a part of the through hole is formed.

As shown in FIG. 7D, the second electrode 36 is formed in an area including the portion for flip chip bonding and a through hole in which the first electrode is formed by flipping the substrate, and then LED and flip chip bonding occur. The solder layer 36 is formed in the part. It can be manufactured through a process similar to the method of forming the package 30 according to the first embodiment of the present invention (FIGS. 3A-3G).

FIG. 8 shows the package 30 formed in FIGS. 7A to 7D mounted on the stem 40 on which the electrode wiring 42 is formed. Fast and reliable external power junctions can be achieved using flip chip bonding. By arranging the LED package 30 in a variety of structures in the same way as described above it can form a lighting device for a variety of uses.

9A to 9C are cross-sectional views illustrating a manufacturing process of still another embodiment of the present invention. As shown in FIG. 9A, a part of a lower part or an upper part of a silicon substrate 31 having an insulating layer 33 is formed by a bulk micromachining process. As a result, the silicon substrate 31 is removed from the surface of the silicon substrate 31 on the other side of the silicon substrate 31 through a machining process to form a through hole using only the bulk micro machining process.

Next, as shown in FIG. 9B, a first electrode 34 is formed on at least a portion of the upper portion and the through hole of the substrate.

Then, as shown in FIG. 9C, the structure is inverted to form a second electrode 36 connected to at least a portion of the first electrode layer 34 and providing a pad for flip chip bonding with external electrode wiring. The solder layer 35 is formed on the first electrode 34 and the second electrode 36.

FIG. 10 shows the package 30 formed in FIGS. 9A to 9C mounted on the stem 40 on which the electrode wiring 42 is formed. Fast and reliable external power junctions can be achieved using flip chip bonding. By arranging the LED package 30 in a variety of structures in the same way as described above it can form a lighting device for a variety of uses.

In order to implement various kinds of lighting devices by aligning the package in which the LEDs are arranged, as described above, the upper and lower electrodes of the sub-mount are extended through the through holes to enable flip chip bonding, thereby improving process time and reliability. It is possible to effectively dissipate the generated heat. Therefore, the configurations of the present invention can be effectively utilized in various applications such as a backlight for a display device, a simple light, a traffic light, a display light of a vehicle, and the like.

As described above, the LED lighting apparatus and the manufacturing method thereof according to the present invention form a through hole on a silicon sub-mount, form an electrode connected to the LED electrode on the front side, and form an electrode for flip chip bonding on the back side. The electrodes are interconnected through a through hole so that a package in which an LED is placed can be bonded to a stem having electrode wiring for providing LED power, thereby greatly increasing process time, cost, and reliability. Since it is directly connected through the electrode passing through the through-hole, the heat dissipation effect is greatly increased, thereby improving the lifespan and characteristics of the device.

Claims (15)

In the light emitting diode illumination device is arranged a plurality of light emitting diodes, A stem comprising an insulating layer, an electrode wiring layer on the insulating layer for supplying power to a plurality of light emitting diodes on the same plane, and a solder layer on the electrode wiring layer; It is formed of a silicon substrate, the groove is located in the light emitting diode mounting portion, the first electrode formed on the front surface of the substrate and the second electrode formed on the back of the substrate through the through hole located in the groove to be connected to the light emitting diode electrode A sub-mount connected to each other and connected to a power line on the stem by using the second electrode; And a light emitting diode bonded to the first electrode of the sub-mount. delete The light emitting diode lighting apparatus of claim 1, further comprising a reflective layer in the groove of the sub-mount. The light emitting diode illuminating device according to claim 1, wherein a groove is located on a lower side of the silicon sub-mount. 5. The LED lighting apparatus of claim 4, wherein the second electrode is positioned on the groove. The light emitting diode lighting apparatus according to claim 1, wherein the through hole has an inclined surface that is not vertical. Forming an insulating layer on the silicon substrate; Forming a groove on a lower side of the silicon substrate; Forming at least one through hole penetrating the front and rear surfaces of the substrate; Forming a first electrode connected to an electrode of a light emitting diode on an insulating layer on the front surface of the substrate; Forming a second electrode on a rear surface of the substrate through the first electrode and the through hole; And cutting a separation region of the substrate. The method of claim 7, wherein the forming of the grooves comprises using a bulk micromachining process. delete In the method of manufacturing a light emitting diode package, Forming an insulating layer on the silicon substrate; Forming through-holes inclined by etching on both sides of a portion on which the light emitting diode is mounted; Forming a first electrode connected to an electrode of a light emitting diode on an insulating layer on the front surface of the substrate; Forming a second electrode on a rear surface of the substrate through the first electrode and the through hole; And cutting a separation region of the substrate. delete The method of claim 10, further comprising forming a groove in a portion where the light emitting diode is to be mounted before forming the insulating layer on the silicon substrate. In the light emitting diode package, A groove on which the light emitting diode is mounted is formed, the substrate comprising silicon; A through hole formed through the substrate inside the groove and having an inclined surface at least in part; An insulating layer formed on at least one surface of an outer surface of the substrate; And a pair of electrodes formed by connecting an upper surface and a lower surface of the substrate through the through hole. The light emitting diode package of claim 13, wherein the electrode is formed on the insulating layer. delete

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